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diff --git a/doc/rfc/rfc5213.txt b/doc/rfc/rfc5213.txt new file mode 100644 index 0000000..cafd88f --- /dev/null +++ b/doc/rfc/rfc5213.txt @@ -0,0 +1,5155 @@ + + + + + + +Network Working Group S. Gundavelli, Ed. +Request for Comments: 5213 K. Leung +Category: Standards Track Cisco + V. Devarapalli + Wichorus + K. Chowdhury + Starent Networks + B. Patil + Nokia + August 2008 + + + Proxy Mobile IPv6 + +Status of This Memo + + This document specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" (STD 1) for the standardization state + and status of this protocol. Distribution of this memo is unlimited. + +Abstract + + Network-based mobility management enables IP mobility for a host + without requiring its participation in any mobility-related + signaling. The network is responsible for managing IP mobility on + behalf of the host. The mobility entities in the network are + responsible for tracking the movements of the host and initiating the + required mobility signaling on its behalf. This specification + describes a network-based mobility management protocol and is + referred to as Proxy Mobile IPv6. + + + + + + + + + + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 1] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +Table of Contents + + 1. Introduction ................................................. 4 + 2. Conventions and Terminology ................................. 5 + 2.1. Conventions Used in This Document ....................... 5 + 2.2. Terminology ............................................. 5 + 3. Proxy Mobile IPv6 Protocol Overview ......................... 9 + 4. Proxy Mobile IPv6 Protocol Security ......................... 15 + 4.1. Peer Authorization Database (PAD) Example Entries ....... 16 + 4.2. Security Policy Database (SPD) Example Entries ........... 17 + 5. Local Mobility Anchor Operation ............................. 17 + 5.1. Extensions to Binding Cache Entry Data Structure ......... 18 + 5.2. Supported Home Network Prefix Models ..................... 19 + 5.3. Signaling Considerations ................................. 20 + 5.3.1. Processing Proxy Binding Updates ..................... 20 + 5.3.2. Initial Binding Registration (New Mobility Session) .. 22 + 5.3.3. Binding Lifetime Extension (No Handoff) ............. 23 + 5.3.4. Binding Lifetime Extension (After Handoff) ........... 24 + 5.3.5. Binding De-Registration ............................. 24 + 5.3.6. Constructing the Proxy Binding Acknowledgement + Message ............................................. 25 + 5.4. Multihoming Support ..................................... 27 + 5.4.1. Binding Cache Entry Lookup Considerations ........... 28 + 5.5. Timestamp Option for Message Ordering ................... 34 + 5.6. Routing Considerations ................................... 37 + 5.6.1. Bi-Directional Tunnel Management ..................... 37 + 5.6.2. Forwarding Considerations ........................... 38 + 5.6.3. Explicit Congestion Notification (ECN) + Considerations for Proxy Mobile IPv6 Tunnels ......... 39 + 5.7. Local Mobility Anchor Address Discovery ................. 40 + 5.8. Mobile Prefix Discovery Considerations ................... 40 + 5.9. Route Optimization Considerations ....................... 41 + 6. Mobile Access Gateway Operation ............................. 41 + 6.1. Extensions to Binding Update List Entry Data Structure ... 42 + 6.2. Mobile Node's Policy Profile ............................. 43 + 6.3. Supported Access Link Types ............................. 44 + 6.4. Supported Address Configuration Modes ................... 44 + 6.5. Access Authentication and Mobile Node Identification ..... 45 + 6.6. Acquiring Mobile Node's Identifier ....................... 45 + 6.7. Home Network Emulation ................................... 46 + 6.8. Link-local and Global Address Uniqueness ................. 46 + 6.9. Signaling Considerations ................................. 48 + 6.9.1. Binding Registrations ............................... 48 + 6.9.2. Router Solicitation Messages ......................... 56 + 6.9.3. Default-Router ....................................... 57 + 6.9.4. Retransmissions and Rate Limiting ................... 58 + 6.9.5. Path MTU Discovery ................................... 59 + 6.10. Routing Considerations ................................... 60 + + + +Gundavelli, et al. Standards Track [Page 2] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + 6.10.1. Transport Network ................................... 60 + 6.10.2. Tunneling and Encapsulation Modes ................... 61 + 6.10.3. Local Routing ....................................... 62 + 6.10.4. Tunnel Management ................................... 62 + 6.10.5. Forwarding Rules ..................................... 62 + 6.11. Supporting DHCP-Based Address Configuration on the + Access Link ............................................. 64 + 6.12. Home Network Prefix Renumbering ......................... 66 + 6.13. Mobile Node Detachment Detection and Resource Cleanup ... 66 + 6.14. Allowing Network Access to Other IPv6 Nodes ............. 67 + 7. Mobile Node Operation ....................................... 67 + 7.1. Moving into a Proxy Mobile IPv6 Domain ................... 67 + 7.2. Roaming in the Proxy Mobile IPv6 Domain ................. 69 + 8. Message Formats ............................................. 69 + 8.1. Proxy Binding Update Message ............................. 69 + 8.2. Proxy Binding Acknowledgement Message ................... 71 + 8.3. Home Network Prefix Option ............................... 72 + 8.4. Handoff Indicator Option ................................. 73 + 8.5. Access Technology Type Option ........................... 74 + 8.6. Mobile Node Link-layer Identifier Option ................. 76 + 8.7. Link-local Address Option ............................... 77 + 8.8. Timestamp Option ......................................... 77 + 8.9. Status Values ........................................... 78 + 9. Protocol Configuration Variables ............................. 80 + 9.1. Local Mobility Anchor - Configuration Variables ......... 80 + 9.2. Mobile Access Gateway - Configuration Variables ......... 81 + 9.3. Proxy Mobile IPv6 Domain - Configuration Variables ....... 82 + 10. IANA Considerations ......................................... 83 + 11. Security Considerations ..................................... 84 + 12. Acknowledgements ............................................. 85 + 13. References ................................................... 86 + 13.1. Normative References ..................................... 86 + 13.2. Informative References ................................... 87 + Appendix A. Proxy Mobile IPv6 Interactions with AAA + Infrastructure ..................................... 89 + Appendix B. Routing State ....................................... 89 + + + + + + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 3] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +1. Introduction + + IP mobility for IPv6 hosts is specified in Mobile IPv6 [RFC3775]. + Mobile IPv6 requires client functionality in the IPv6 stack of a + mobile node. Exchange of signaling messages between the mobile node + and home agent enables the creation and maintenance of a binding + between the mobile node's home address and its care-of address. + Mobility as specified in [RFC3775] requires the IP host to send IP + mobility management signaling messages to the home agent, which is + located in the network. + + Network-based mobility is another approach to solving the IP mobility + challenge. It is possible to support mobility for IPv6 nodes without + host involvement by extending Mobile IPv6 [RFC3775] signaling + messages between a network node and a home agent. This approach to + supporting mobility does not require the mobile node to be involved + in the exchange of signaling messages between itself and the home + agent. A proxy mobility agent in the network performs the signaling + with the home agent and does the mobility management on behalf of the + mobile node attached to the network. Because of the use and + extension of Mobile IPv6 signaling and home agent functionality, this + protocol is referred to as Proxy Mobile IPv6 (PMIPv6). + + Network deployments that are designed to support mobility would be + agnostic to the capability in the IPv6 stack of the nodes that it + serves. IP mobility for nodes that have mobile IP client + functionality in the IPv6 stack as well as those nodes that do not, + would be supported by enabling Proxy Mobile IPv6 protocol + functionality in the network. The advantages of developing a + network-based mobility protocol based on Mobile IPv6 are: + + o Reuse of home agent functionality and the messages/format used in + mobility signaling. Mobile IPv6 is a mature protocol with several + implementations that have undergone interoperability testing. + + o A common home agent would serve as the mobility agent for all + types of IPv6 nodes. + + The problem statement and the need for a network-based mobility + protocol solution has been documented in [RFC4830]. Proxy Mobile + IPv6 is a solution that addresses these issues and requirements. + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 4] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +2. Conventions and Terminology + +2.1. Conventions Used in This Document + + The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", + "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this + document are to be interpreted as described in RFC 2119 [RFC2119]. + +2.2. Terminology + + All the general mobility-related terms used in this document are to + be interpreted as defined in the Mobile IPv6 base specification + [RFC3775]. + + This document adopts the terms, Local Mobility Anchor (LMA) and + Mobile Access Gateway (MAG) from the NETLMM Goals document [RFC4831]. + This document also provides the following context-specific + explanation to the following terms used in this document. + + Proxy Mobile IPv6 Domain (PMIPv6-Domain) + + Proxy Mobile IPv6 domain refers to the network where the mobility + management of a mobile node is handled using the Proxy Mobile IPv6 + protocol as defined in this specification. The Proxy Mobile IPv6 + domain includes local mobility anchors and mobile access gateways + between which security associations can be set up and + authorization for sending Proxy Binding Updates on behalf of the + mobile nodes can be ensured. + + Local Mobility Anchor (LMA) + + Local Mobility Anchor is the home agent for the mobile node in a + Proxy Mobile IPv6 domain. It is the topological anchor point for + the mobile node's home network prefix(es) and is the entity that + manages the mobile node's binding state. The local mobility + anchor has the functional capabilities of a home agent as defined + in Mobile IPv6 base specification [RFC3775] with the additional + capabilities required for supporting Proxy Mobile IPv6 protocol as + defined in this specification. + + Mobile Access Gateway (MAG) + + Mobile Access Gateway is a function on an access router that + manages the mobility-related signaling for a mobile node that is + attached to its access link. It is responsible for tracking the + mobile node's movements to and from the access link and for + signaling the mobile node's local mobility anchor. + + + + +Gundavelli, et al. Standards Track [Page 5] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + Mobile Node (MN) + + Throughout this document, the term mobile node is used to refer to + an IP host or router whose mobility is managed by the network. + The mobile node may be an IPv4-only node, IPv6-only node, or a + dual-stack node and is not required to participate in any IP + mobility related signaling for achieving mobility for an IP + address that is obtained in that Proxy Mobile IPv6 domain. + + LMA Address (LMAA) + + The global address that is configured on the interface of the + local mobility anchor and is the transport endpoint of the bi- + directional tunnel established between the local mobility anchor + and the mobile access gateway. This is the address to which the + mobile access gateway sends the Proxy Binding Update messages. + When supporting IPv4 traversal, i.e., when the network between the + local mobility anchor and the mobile access gateway is an IPv4 + network, this address will be an IPv4 address and will be referred + to as IPv4-LMAA, as specified in [IPV4-PMIP6]. + + Proxy Care-of Address (Proxy-CoA) + + Proxy-CoA is the global address configured on the egress interface + of the mobile access gateway and is the transport endpoint of the + tunnel between the local mobility anchor and the mobile access + gateway. The local mobility anchor views this address as the + care-of address of the mobile node and registers it in the Binding + Cache entry for that mobile node. When the transport network + between the mobile access gateway and the local mobility anchor is + an IPv4 network and if the care-of address that is registered at + the local mobility anchor is an IPv4 address, the term, IPv4- + Proxy-CoA is used, as specified in [IPV4-PMIP6]. + + Mobile Node's Home Network Prefix (MN-HNP) + + The MN-HNP is a prefix assigned to the link between the mobile + node and the mobile access gateway. More than one prefix can be + assigned to the link between the mobile node and the mobile access + gateway, in which case, all of the assigned prefixes are managed + as a set associated with a mobility session. The mobile node + configures its interface with one or more addresses from its home + network prefix(es). If the mobile node connects to the Proxy + Mobile IPv6 domain through multiple interfaces, simultaneously, + each of the attached interfaces will be assigned a unique set of + home network prefixes, and all the prefixes assigned to a given + interface of a mobile node will be managed under one mobility + session. For example, home network prefixes P1 and P2 assigned to + + + +Gundavelli, et al. Standards Track [Page 6] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + interface I1 will be managed under one mobility session and + prefixes P3, P4, and P5 assigned to interface I2 of the mobile + node will be managed under a different mobility session. + Additionally, in some configurations the assigned prefix can be of + 128-bit prefix length. + + Mobile Node's Home Address (MN-HoA) + + MN-HoA is an address from a mobile node's home network prefix. + The mobile node will be able to use this address as long as it is + attached to the access network that is in the scope of that Proxy + Mobile IPv6 domain. If the mobile node uses more than one address + from its home network prefix(es), any one of these addresses is + referred to as mobile node's home address. Unlike in Mobile IPv6 + where the home agent is aware of the home address of the mobile + node, in Proxy Mobile IPv6, the mobility entities are only aware + of the mobile node's home network prefix(es) and are not always + aware of the exact address(es) that the mobile node configured on + its interface from its home network prefix(es). However, in some + configurations and based on the enabled address configuration + modes on the access link, the mobility entities in the network can + be certain about the exact address(es) configured by the mobile + node. + + Mobile Node's Home Link + + This is the link on which the mobile node obtained its layer-3 + address configuration for the attached interface after it moved + into that Proxy Mobile IPv6 domain. This is the link that + conceptually follows the mobile node. The network will ensure the + mobile node always sees this link with respect to the layer-3 + network configuration, on any access link that it attaches to in + that Proxy Mobile IPv6 domain. + + Multihomed Mobile Node + + A mobile node that connects to the same Proxy Mobile IPv6 domain + through more than one interface and uses these interfaces + simultaneously is referred to as a multihomed mobile node. + + Mobile Node Identifier (MN-Identifier) + + The identity of a mobile node in the Proxy Mobile IPv6 domain. + This is the stable identifier of a mobile node that the mobility + entities in a Proxy Mobile IPv6 domain can always acquire and use + for predictably identifying a mobile node. This is typically an + identifier such as a Network Access Identifier (NAI) [RFC4282] or + other identifier such as a Media Access Control (MAC) address. + + + +Gundavelli, et al. Standards Track [Page 7] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + Mobile Node Link-layer Identifier (MN-LL-Identifier) + + An identifier that identifies the attached interface of a mobile + node. For those interfaces that have a link-layer identifier, + this identifier can be based on that. The link-layer identifier, + in some cases, is generated by the mobile node and conveyed to the + mobile access gateway. This identifier of the attached interface + must be stable, as seen by any of the mobile access gateways in a + given Proxy Mobile IPv6 domain. In some other cases, there might + not be any link-layer identifier associated with the mobile node's + interface. An identifier value of ALL_ZERO is not considered a + valid identifier and cannot be used as an interface identifier. + + Policy Profile + + Policy Profile is an abstract term for referring to a set of + configuration parameters that are configured for a given mobile + node. The mobility entities in the Proxy Mobile IPv6 domain + require access to these parameters for providing the mobility + management to a given mobile node. The specific details on how + the network entities obtain this policy profile is outside the + scope of this document. + + Proxy Binding Update (PBU) + + A request message sent by a mobile access gateway to a mobile + node's local mobility anchor for establishing a binding between + the mobile node's home network prefix(es) assigned to a given + interface of a mobile node and its current care-of address (Proxy- + CoA). + + Proxy Binding Acknowledgement (PBA) + + A reply message sent by a local mobility anchor in response to a + Proxy Binding Update message that it received from a mobile access + gateway. + + Per-MN-Prefix and Shared-Prefix Models + + The term Per-MN-Prefix model is used to refer to an addressing + model where there is a unique network prefix or prefixes assigned + for each node. The term Shared-Prefix model is used to refer to + an addressing model where the prefix(es) are shared by more than + one node. This specification supports the Per-MN-Prefix model and + does not support the Shared-Prefix model. + + + + + + +Gundavelli, et al. Standards Track [Page 8] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + Mobility Session + + In the context of Proxy Mobile IPv6 specification, the term + mobility session refers to the creation or existence of state + associated with the mobile node's mobility binding on the local + mobility anchor and on the serving mobile access gateway. + + DHCP + + Throughout this document, the acronym DHCP refers to DHCP for + IPv6, as defined in [RFC3315]. + + ALL_ZERO and NON_ZERO + + Protocol message fields initialized with value 0 in each byte of + the field. For example, an 8-byte link-layer identifier field + with the value set to 0 in each of the 8 bytes, or an IPv6 address + with the value 0 in all of the 16 bytes. Conversely, the term + NON_ZERO is used to refer to any value other than an ALL_ZERO + value. + +3. Proxy Mobile IPv6 Protocol Overview + + This specification describes a network-based mobility management + protocol. It is called Proxy Mobile IPv6 and is based on Mobile IPv6 + [RFC3775]. + + Proxy Mobile IPv6 protocol is intended for providing network-based IP + mobility management support to a mobile node, without requiring the + participation of the mobile node in any IP mobility related + signaling. The mobility entities in the network will track the + mobile node's movements and will initiate the mobility signaling and + set up the required routing state. + + The core functional entities in the NETLMM infrastructure are the + Local Mobility Anchor (LMA) and the Mobile Access Gateway (MAG). The + local mobility anchor is responsible for maintaining the mobile + node's reachability state and is the topological anchor point for the + mobile node's home network prefix(es). The mobile access gateway is + the entity that performs the mobility management on behalf of a + mobile node, and it resides on the access link where the mobile node + is anchored. The mobile access gateway is responsible for detecting + the mobile node's movements to and from the access link and for + initiating binding registrations to the mobile node's local mobility + anchor. There can be multiple local mobility anchors in a Proxy + Mobile IPv6 domain each serving a different group of mobile nodes. + The architecture of a Proxy Mobile IPv6 domain is shown in Figure 1. + + + + +Gundavelli, et al. Standards Track [Page 9] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + +----+ +----+ + |LMA1| |LMA2| + +----+ +----+ + LMAA1 -> | | <-- LMAA2 + | | + \\ //\\ + \\ // \\ + \\ // \\ + +---\\------------- //------\\----+ + ( \\ IPv4/IPv6 // \\ ) + ( \\ Network // \\ ) + +------\\--------//------------\\-+ + \\ // \\ + \\ // \\ + \\ // \\ + Proxy-CoA1--> | | <-- Proxy-CoA2 + +----+ +----+ + |MAG1|-----{MN2} |MAG2| + +----+ | +----+ + | | | + MN-HNP1 --> | MN-HNP2 | <-- MN-HNP3, MN-HNP4 + {MN1} {MN3} + + Figure 1: Proxy Mobile IPv6 Domain + + When a mobile node enters a Proxy Mobile IPv6 domain and attaches to + an access link, the mobile access gateway on that access link, after + identifying the mobile node and acquiring its identity, will + determine if the mobile node is authorized for the network-based + mobility management service. + + If the network determines that the mobile node is authorized for + network-based mobility service, the network will ensure that the + mobile node using any of the address configuration mechanisms + permitted by the network will be able to obtain the address + configuration on the connected interface and move anywhere in that + Proxy Mobile IPv6 domain. The obtained address configuration + includes the address(es) from its home network prefix(es), the + default-router address on the link, and other related configuration + parameters. From the perspective of each mobile node, the entire + Proxy Mobile IPv6 domain appears as a single link, the network + ensures that the mobile node does not detect any change with respect + to its layer-3 attachment even after changing its point of attachment + in the network. + + + + + + + +Gundavelli, et al. Standards Track [Page 10] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + The mobile node may be an IPv4-only node, IPv6-only node, or a dual- + stack (IPv4/v6) node. Based on the policy profile information that + indicates the type of address or prefixes to be assigned for the + mobile node in the network, the mobile node will be able to obtain an + IPv4, IPv6, or dual IPv4/IPv6 address and move anywhere in that Proxy + Mobile IPv6 domain. However, this specification only supports IPv6 + address/prefix mobility with the transport network being IPv6. The + support for IPv4 addressing or an IPv4 transport network is specified + in the companion document [IPV4-PMIP6]. + + If the mobile node connects to the Proxy Mobile IPv6 domain through + multiple interfaces and over multiple access networks, the network + will allocate a unique set of home network prefixes for each of the + connected interfaces. The mobile node will be able to configure + address(es) on those interfaces from the respective home network + prefix(es). However, if the mobile node performs a handoff by moving + its address configuration from one interface to the other, and if the + local mobility anchor receives a handoff hint from the serving mobile + access gateway about the same, the local mobility anchor will assign + the same home network prefix(es) that it previously assigned prior to + the handoff. The mobile node will also be able to perform a handoff + by changing its point of attachment from one mobile access gateway to + a different mobile access gateway using the same interface and will + be able to retain the address configuration on the attached + interface. + + + + + + + + + + + + + + + + + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 11] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + +-----+ +-----+ +-----+ + | MN | | MAG | | LMA | + +-----+ +-----+ +-----+ + | | | + MN Attached | | + | | | + | MN Attached Event from MN/Network | + | (Acquire MN-Id and Profile) | + | | | + |--- Rtr Sol --------->| | + | | | + | |--- PBU ------------->| + | | | + | | Accept PBU + | | (Allocate MN-HNP(s), Setup BCE and Tunnel) + | | | + | |<------------- PBA ---| + | | | + | Accept PBA | + | (Set Up Tunnel and Routing) | + | | | + | |==== Bi-Dir Tunnel ===| + | | | + |<--------- Rtr Adv ---| | + | | | + IP Address | | + Configuration | | + | | | + + Figure 2: Mobile Node Attachment - Signaling Call Flow + + Figure 2 shows the signaling call flow when the mobile node enters + the Proxy Mobile IPv6 domain. The Router Solicitation message from + the mobile node may arrive at any time after the mobile node's + attachment and has no strict ordering relation with the other + messages in the call flow. + + For updating the local mobility anchor about the current location of + the mobile node, the mobile access gateway sends a Proxy Binding + Update message to the mobile node's local mobility anchor. Upon + accepting this Proxy Binding Update message, the local mobility + anchor sends a Proxy Binding Acknowledgement message including the + mobile node's home network prefix(es). It also creates the Binding + Cache entry and sets up its endpoint of the bi-directional tunnel to + the mobile access gateway. + + + + + + +Gundavelli, et al. Standards Track [Page 12] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + The mobile access gateway on receiving the Proxy Binding + Acknowledgement message sets up its endpoint of the bi-directional + tunnel to the local mobility anchor and also sets up the forwarding + for the mobile node's traffic. At this point, the mobile access + gateway has all the required information for emulating the mobile + node's home link. It sends Router Advertisement messages to the + mobile node on the access link advertising the mobile node's home + network prefix(es) as the hosted on-link prefix(es). + + The mobile node, on receiving these Router Advertisement messages on + the access link, attempts to configure its interface using either + stateful or stateless address configuration modes, based on the modes + that are permitted on that access link as indicated in Router + Advertisement messages. At the end of a successful address + configuration procedure, the mobile node has one or more addresses + from its home network prefix(es). + + After address configuration, the mobile node has one or more valid + addresses from its home network prefix(es) at the current point of + attachment. The serving mobile access gateway and the local mobility + anchor also have proper routing states for handling the traffic sent + to and from the mobile node using any one or more of the addresses + from its home network prefix(es). + + The local mobility anchor, being the topological anchor point for the + mobile node's home network prefix(es), receives any packets that are + sent to the mobile node by any node in or outside the Proxy Mobile + IPv6 domain. The local mobility anchor forwards these received + packets to the mobile access gateway through the bi-directional + tunnel. The mobile access gateway on other end of the tunnel, after + receiving the packet, removes the outer header and forwards the + packet on the access link to the mobile node. However, in some + cases, the traffic sent from a correspondent node that is locally + connected to the mobile access gateway may not be received by the + local mobility anchor and may be routed locally by the mobile access + gateway (refer to Section 6.10.3). + + The mobile access gateway acts as the default router on the point-to- + point link shared with the mobile node. Any packet that the mobile + node sends to any correspondent node will be received by the mobile + access gateway and will be sent to its local mobility anchor through + the bi-directional tunnel. The local mobility anchor on the other + end of the tunnel, after receiving the packet, removes the outer + header and routes the packet to the destination. However, in some + cases, the traffic sent to a correspondent node that is locally + connected to the mobile access gateway may be locally routed by the + mobile access gateway (refer to Section 6.10.3). + + + + +Gundavelli, et al. Standards Track [Page 13] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + +-----+ +-----+ +-----+ +-----+ + | MN | |p-MAG| | LMA | |n-MAG| + +-----+ +-----+ +-----+ +-----+ + | | | | + | |==Bi-Dir Tunnel=| | + MN Detached | | | + | MN Detached Event | | + | | | | + | |-- DeReg PBU -->| | + | | | | + | | Accept PBU | + | | (Start MinDelayBeforeBCEDelete Timer) + | | | | + | |<-------- PBA --| | + | | | | + MN Attached | | | + | | | MN Attached event received + | | | from MN or from network + | | | (Acquire MN-Id and Profile) + | | | | + |--- Rtr Sol ------------------------------------->| + .... + Registration steps as in Fig. 2. + .... + | | |==Bi-Dir Tunnel=| + | | | | + |<------------------------------------ Rtr Adv ----| + | | | | + MN retains HoA/HNP(s) + | | | | + + Figure 3: Mobile Node Handoff - Signaling Call Flow + + Figure 3 shows the signaling call flow for the mobile node's handoff + from the previously attached mobile access gateway (p-MAG) to the + newly attached mobile access gateway (n-MAG). This call flow only + reflects a specific message ordering, it is possible the registration + message from the n-MAG may arrive before the de-registration message + from the p-MAG arrives. + + After obtaining the initial address configuration in the Proxy Mobile + IPv6 domain, if the mobile node changes its point of attachment, the + mobile access gateway on the previous link will detect the mobile + node's detachment from the link. It will signal the local mobility + anchor and will remove the binding and routing state for that mobile + node. The local mobility anchor, upon receiving this request, will + identify the corresponding mobility session for which the request was + + + + +Gundavelli, et al. Standards Track [Page 14] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + received, and accepts the request after which it waits for a certain + amount of time to allow the mobile access gateway on the new link to + update the binding. However, if it does not receive any Proxy + Binding Update message within the given amount of time, it will + delete the binding cache entry. + + The mobile access gateway on the new access link, upon detecting the + mobile node on its access link, will signal the local mobility anchor + to update the binding state. After completion of the signaling, the + serving mobile access gateway will send the Router Advertisements + containing the mobile node's home network prefix(es), and this will + ensure the mobile node will not detect any change with respect to the + layer-3 attachment of its interface. + +4. Proxy Mobile IPv6 Protocol Security + + The signaling messages, Proxy Binding Update, and Proxy Binding + Acknowledgement, exchanged between the mobile access gateway and the + local mobility anchor, MUST be protected using end-to-end security + association(s) offering integrity and data origin authentication. + + The mobile access gateway and the local mobility anchor MUST + implement IPsec for protecting the Proxy Mobile IPv6 signaling + messages [RFC4301]. IPsec is a mandatory-to-implement security + mechanism. However, additional documents may specify alternative + mechanisms and the mobility entities can enable a specific mechanism + for securing Proxy Mobile IPv6 signaling messages, based on either a + static configuration or after a dynamic negotiation using any + standard security negotiation protocols. As in Mobile IPv6 + [RFC3775], the use of IPsec for protecting a mobile node's data + traffic is optional. + + IPsec Encapsulating Security Payload (ESP) [RFC4303] in transport + mode with mandatory integrity protection SHOULD be used for + protecting the signaling messages. Confidentiality protection of + these messages is not required. + + IPsec ESP [RFC4303] in tunnel mode MAY be used to protect the mobile + node's tunneled data traffic, if protection of data traffic is + required. + + Internet Key Exchange Protocol version 2 (IKEv2) [RFC4306] SHOULD be + used to set up security associations between the mobile access + gateway and the local mobility anchor to protect the Proxy Binding + Update and Proxy Binding Acknowledgement messages. The mobile access + gateway and the local mobility anchor can use any of the + authentication mechanisms, as specified in [RFC4306], for mutual + authentication. + + + +Gundavelli, et al. Standards Track [Page 15] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + The Mobile IPv6 specification [RFC3775] requires the home agent to + prevent a mobile node from creating security associations or creating + binding cache entries for another mobile node's home address. In the + protocol described in this document, the mobile node is not involved + in creating security associations for protecting the signaling + messages or sending binding updates. Therefore, the local mobility + anchor MUST restrict the creation and manipulation of proxy bindings + to specifically authorized mobile access gateways and prefixes. The + local mobility anchor MUST be locally configurable to authorize such + specific combinations. Additional mechanisms, such as a policy store + or Authentication, Authorization, and Accounting (AAA) may be + employed, but these are outside the scope of this specification. + + Unlike in Mobile IPv6 [RFC3775], these signaling messages do not + carry either the Home Address destination option or the Type 2 + Routing header, and hence the policy entries and security association + selectors stay the same and require no special IPsec related + considerations. + +4.1. Peer Authorization Database (PAD) Example Entries + + This section describes PAD entries [RFC4301] on the mobile access + gateway and the local mobility anchor. The PAD entries are only + example configurations. Note that the PAD is a logical concept and a + particular mobile access gateway or a local mobility anchor + implementation can implement the PAD in any implementation-specific + manner. The PAD state may also be distributed across various + databases in a specific implementation. + + In the example shown below, the identity of the local mobility anchor + is assumed to be lma_identity_1 and the identity of the mobile access + gateway is assumed to be mag_identity_1. + + mobile access gateway PAD: + - IF remote_identity = lma_identity_1 + Then authenticate (shared secret/certificate/EAP) + and authorize CHILD_SAs for remote address lma_address_1 + + local mobility anchor PAD: + - IF remote_identity = mag_identity_1 + Then authenticate (shared secret/certificate/EAP) + and authorize CHILD_SAs for remote address mag_address_1 + + Figure 4: PAD Entries + + + + + + + +Gundavelli, et al. Standards Track [Page 16] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + The list of authentication mechanisms in the above examples is not + exhaustive. There could be other credentials used for authentication + stored in the PAD. + +4.2. Security Policy Database (SPD) Example Entries + + This section describes the security policy entries [RFC4301] on the + mobile access gateway and the local mobility anchor required to + protect the Proxy Mobile IPv6 signaling messages. The SPD entries + are only example configurations. A particular mobile access gateway + or a local mobility anchor implementation could configure different + SPD entries as long as they provide the required security. + + In the example shown below, the identity of the mobile access gateway + is assumed to be mag_identity_1, the address of the mobile access + gateway is assumed to be mag_address_1, and the address of the local + mobility anchor is assumed to be lma_address_1. The acronym MH + represents the protocol number for the Mobility Header [RFC3775], + while the terms local_mh_type and remote_mh_type stand for local + mobility header type and remote mobility header type, respectively. + + mobile access gateway SPD-S: + - IF local_address = mag_address_1 & + remote_address = lma_address_1 & + proto = MH & (local_mh_type = BU | remote_mh_type = BA) + Then use SA ESP transport mode + Initiate using IDi = mag_identity_1 to address lma_address_1 + + local mobility anchor SPD-S: + - IF local_address = lma_address_1 & + remote_address = mag_address_1 & + proto = MH & (local_mh_type = BA | remote_mh_type = BU) + Then use SA ESP transport mode + + Figure 5: SPD Entries + +5. Local Mobility Anchor Operation + + The local mobility anchor MUST support the home agent function as + defined in [RFC3775] and the extensions defined in this + specification. A home agent with these modifications and enhanced + capabilities for supporting the Proxy Mobile IPv6 protocol is + referred to as a local mobility anchor. + + This section describes the operational details of the local mobility + anchor. + + + + + +Gundavelli, et al. Standards Track [Page 17] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +5.1. Extensions to Binding Cache Entry Data Structure + + Every local mobility anchor MUST maintain a Binding Cache entry for + each currently registered mobile node. A Binding Cache entry is a + conceptual data structure, described in Section 9.1 of [RFC3775]. + + For supporting this specification, the Binding Cache Entry data + structure needs to be extended with the following additional fields. + + o A flag indicating whether or not this Binding Cache entry is + created due to a proxy registration. This flag is set to value 1 + for Binding Cache entries that are proxy registrations and is set + to value 0 for all other entries. + + o The identifier of the registered mobile node, MN-Identifier. This + identifier is obtained from the Mobile Node Identifier Option + [RFC4283] present in the received Proxy Binding Update message. + + o The link-layer identifier of the mobile node's connected interface + on the access link. This identifier can be acquired from the + Mobile Node Link-layer Identifier option, present in the received + Proxy Binding Update message. If the option was not present in + the request, this variable length field MUST be set to two + (octets) and MUST be initialized to a value of ALL_ZERO. + + o The link-local address of the mobile access gateway on the point- + to-point link shared with the mobile node. This is generated by + the local mobility anchor after accepting the initial Proxy + Binding Update message. + + o A list of IPv6 home network prefixes assigned to the mobile node's + connected interface. The home network prefix(es) may have been + statically configured in the mobile node's policy profile, or, + they may have been dynamically allocated by the local mobility + anchor. Each one of these prefix entries will also include the + corresponding prefix length. + + o The tunnel interface identifier (tunnel-if-id) of the bi- + directional tunnel between the local mobility anchor and the + mobile access gateway where the mobile node is currently anchored. + This is internal to the local mobility anchor. The tunnel + interface identifier is acquired during the tunnel creation. + + o The access technology type, by which the mobile node is currently + attached. This is obtained from the Access Technology Type + option, present in the Proxy Binding Update message. + + + + + +Gundavelli, et al. Standards Track [Page 18] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + o The 64-bit timestamp value of the most recently accepted Proxy + Binding Update message sent for this mobile node. This is the + time of day on the local mobility anchor, when the message was + received. If the Timestamp option is not present in the Proxy + Binding Update message (i.e., when the sequence-number-based + scheme is in use), the value MUST be set to ALL_ZERO. + + Typically, any one of the mobile node's home network prefixes from + its mobility session may be used as a key for locating its Binding + Cache entry in all cases except when there has been a handoff of the + mobile node's session to a new mobile access gateway, and that mobile + access gateway is unaware of the home network prefix(es) assigned to + that mobility session. In such handoff cases, the Binding Cache + entry can be located under the considerations specified in Section + 5.4.1. + +5.2. Supported Home Network Prefix Models + + This specification supports the Per-MN-Prefix model and does not + support the Shared-Prefix model. According to the Per-MN-Prefix + model, home network prefix(es) assigned to a mobile node are for that + mobile node's exclusive use and no other node shares an address from + that prefix (other than the Subnet-Router anycast address [RFC4291] + that is used by the mobile access gateway hosting that prefix on that + link). + + There may be more than one prefix assigned to a given interface of + the mobile node; all of those assigned prefixes MUST be unique to + that mobile node, and all are part of exactly one mobility session. + If the mobile node simultaneously attaches to the Proxy Mobile IPv6 + domain through multiple interfaces, each of the attached interfaces + MUST be assigned one or more unique prefixes. Prefixes that are not + assigned to the same interface MUST NOT be managed under the same + mobility session. + + The mobile node's home network prefix(es) assigned to a given + interface of a mobile node (part of a mobility session) will be + hosted on the access link where the mobile node is attached (using + that interface). The local mobility anchor is not required to + perform any proxy Neighbor Discovery (ND) operations [RFC4861] for + defending the mobile node's home address(es), as the prefixes are not + locally hosted on the local mobility anchor. However, from the + routing perspective, the home network prefix(es) is topologically + anchored on the local mobility anchor. + + + + + + + +Gundavelli, et al. Standards Track [Page 19] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +5.3. Signaling Considerations + + This section provides the rules for processing the signaling + messages. The processing rules specified in this section and other + related sections are chained and are in a specific order. When + applying these considerations for processing the signaling messages, + the specified order MUST be maintained. + +5.3.1. Processing Proxy Binding Updates + + 1. The received Proxy Binding Update message (a Binding Update + message with the (P) flag set to value of 1, format specified in + Section 8.1) MUST be authenticated as described in Section 4. + When IPsec is used for message authentication, the Security + Parameter Index (SPI) in the IPsec header [RFC4306] of the + received packet is needed for locating the security association, + for authenticating the Proxy Binding Update message. + + 2. The local mobility anchor MUST observe the rules described in + Section 9.2 of [RFC3775] when processing the Mobility Header in + the received Proxy Binding Update message. + + 3. The local mobility anchor MUST ignore the check, specified in + Section 10.3.1 of [RFC3775], related to the presence of the Home + Address destination option in the Proxy Binding Update message. + + 4. The local mobility anchor MUST identify the mobile node from the + identifier present in the Mobile Node Identifier option + [RFC4283] of the Proxy Binding Update message. If the Mobile + Node Identifier option is not present in the Proxy Binding + Update message, the local mobility anchor MUST reject the + request and send a Proxy Binding Acknowledgement message with + Status field set to MISSING_MN_IDENTIFIER_OPTION (Missing Mobile + Node Identifier option) and the identifier in the Mobile Node + Identifier option carried in the message MUST be set to a zero + length identifier. + + 5. The local mobility anchor MUST apply the required policy checks, + as explained in Section 4, to verify that the sender is a + trusted mobile access gateway authorized to send Proxy Binding + Update messages on behalf of this mobile node. + + 6. If the local mobility anchor determines that the requesting node + is not authorized to send Proxy Binding Update messages for the + identified mobile node, it MUST reject the request and send a + Proxy Binding Acknowledgement message with the Status field set + to MAG_NOT_AUTHORIZED_FOR_PROXY_REG (not authorized to send + proxy binding updates). + + + +Gundavelli, et al. Standards Track [Page 20] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + 7. If the local mobility anchor cannot identify the mobile node + based on the identifier present in the Mobile Node Identifier + option [RFC4283] of the Proxy Binding Update message, it MUST + reject the request and send a Proxy Binding Acknowledgement + message with the Status field set to + NOT_LMA_FOR_THIS_MOBILE_NODE (Not a local mobility anchor for + this mobile node). + + 8. If the local mobility anchor determines that the mobile node is + not authorized for the network-based mobility management + service, it MUST reject the request and send a Proxy Binding + Acknowledgement message with the Status field set to + PROXY_REG_NOT_ENABLED (Proxy Registration not enabled). + + 9. The local mobility anchor MUST apply the considerations + specified in Section 5.5 for processing the Sequence Number + field and the Timestamp option (if present) in the Proxy Binding + Update message. + + 10. If there is no Home Network Prefix option(s) (with any value) + present in the Proxy Binding Update message, the local mobility + anchor MUST reject the request and send a Proxy Binding + Acknowledgement message with the Status field set to + MISSING_HOME_NETWORK_PREFIX_OPTION (Missing Home Network Prefix + option). + + 11. If the Handoff Indicator option is not present in the Proxy + Binding Update message, the local mobility anchor MUST reject + the request and send a Proxy Binding Acknowledgement message + with the Status field set to MISSING_HANDOFF_INDICATOR_OPTION + (Missing Handoff Indicator option). + + 12. If the Access Technology Type option is not present in the Proxy + Binding Update message, the local mobility anchor MUST reject + the request and send a Proxy Binding Acknowledgement message + with the Status field set to MISSING_ACCESS_TECH_TYPE_OPTION + (Missing Access Technology Type option). + + 13. Considerations specified in Section 5.4.1 MUST be applied for + performing the Binding Cache entry existence test. If those + checks specified in Section 5.4.1 result in associating the + received Proxy Binding Update message to a new mobility session + creation request, considerations from Section 5.3.2 (Initial + Binding Registration - New Mobility Session), MUST be applied. + If those checks result in associating the request to an existing + mobility session, the following checks determine the next set of + processing rules that need to be applied. + + + + +Gundavelli, et al. Standards Track [Page 21] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + * If the received Proxy Binding Update message has the lifetime + value of zero, considerations from Section 5.3.5 (Binding De- + Registration) MUST be applied. + + * If the Proxy-CoA in the Binding Cache entry matches the + source address of the request (or the address in the + Alternate Care-of Address option, if the option is present), + considerations from Section 5.3.3 (Binding LIfetime Extension + - No handoff) MUST be applied. + + * For all other cases, considerations from Section 5.3.4 + (Binding Lifetime Extension - After handoff) MUST be applied. + + 14. When sending the Proxy Binding Acknowledgement message with any + Status field value, the message MUST be constructed as specified + in Section 5.3.6. + +5.3.2. Initial Binding Registration (New Mobility Session) + + 1. If there is at least one instance of the Home Network Prefix + option present in the Proxy Binding Update message with the + prefix value set to ALL_ZERO, the local mobility anchor MUST + allocate one or more home network prefixes to the mobile node and + assign it to the new mobility session created for the mobile + node. The local mobility anchor MUST ensure the allocated + prefix(es) is not in use by any other node or mobility session. + The decision on how many prefixes to be allocated for the + attached interface can be based on a global policy or a policy + specific to that mobile node. However, when stateful address + autoconfiguration using DHCP is supported on the link, + considerations from Section 6.11 MUST be applied for the prefix + assignment. + + 2. If the local mobility anchor is unable to allocate any home + network prefix for the mobile node, it MUST reject the request + and send a Proxy Binding Acknowledgement message with the Status + field set to 130 (Insufficient resources). + + 3. If there are one or more Home Network Prefix options present in + the Proxy Binding Update message (with each of the prefixes set + to a NON_ZERO value), the local mobility anchor, before accepting + that request, MUST ensure each one of those prefixes is owned by + the local mobility anchor, and further that the mobile node is + authorized to use these prefixes. If the mobile node is not + authorized to use any one or more of those prefixes, the local + mobility anchor MUST reject the request and send a Proxy Binding + + + + + +Gundavelli, et al. Standards Track [Page 22] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + Acknowledgement message with the Status field set to + NOT_AUTHORIZED_FOR_HOME_NETWORK_PREFIX (mobile node not + authorized for one or more of the requesting home network + prefixes). + + 4. Upon accepting the request, the local mobility anchor MUST create + a Binding Cache entry for the mobile node. It must set the + fields in the Binding Cache entry to the accepted values for that + registration. + + 5. If there is no existing bi-directional tunnel to the mobile + access gateway that sent the request, the local mobility anchor + MUST establish a bi-directional tunnel to that mobile access + gateway. Considerations from Section 5.6.1 MUST be applied for + managing the dynamically created bi-directional tunnel. + + 6. The local mobility anchor MUST create a prefix route(s) over the + tunnel to the mobile access gateway for forwarding any traffic + received for the mobile node's home network prefix(es) associated + with this mobility session. The created tunnel and the routing + state MUST result in the forwarding behavior on the local + mobility anchor as specified in Section 5.6.2. + + 7. The local mobility anchor MUST send the Proxy Binding + Acknowledgement message with the Status field set to 0 (Proxy + Binding Update Accepted). The message MUST be constructed as + specified in Section 5.3.6. + +5.3.3. Binding Lifetime Extension (No Handoff) + + 1. Upon accepting the Proxy Binding Update message for extending the + binding lifetime, received from the same mobile access gateway + (if the Proxy-CoA in the Binding Cache entry is the same as the + Proxy-CoA in the request) that last updated the binding, the + local mobility anchor MUST update the Binding Cache entry with + the accepted registration values. + + 2. The local mobility anchor MUST send the Proxy Binding + Acknowledgement message with the Status field set to 0 (Proxy + Binding Update Accepted). The message MUST be constructed as + specified in Section 5.3.6. + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 23] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +5.3.4. Binding Lifetime Extension (After Handoff) + + 1. Upon accepting the Proxy Binding Update message for extending the + binding lifetime, received from a new mobile access gateway (if + the Proxy-CoA in the Binding Cache entry does not match the + Proxy-CoA in the request) where the mobile node's mobility + session is handed off, the local mobility anchor MUST update the + Binding Cache entry with the accepted registration values. + + 2. The local mobility anchor MUST remove the previously created + route(s) for the mobile node's home network prefix(es) associated + with this mobility session. Additionally, if there are no other + mobile nodes sharing the dynamically created bi-directional + tunnel to the previous mobile access gateway, the tunnel SHOULD + be deleted, applying considerations from section 5.6.1 (if the + tunnel is a dynamically created tunnel and not a fixed pre- + established tunnel). + + 3. If there is no existing bi-directional tunnel to the mobile + access gateway that sent the request, the local mobility anchor + MUST establish a bi-directional tunnel to that mobile access + gateway. Considerations from Section 5.6.1 MUST be applied for + managing the dynamically created bi-directional tunnel. + + 4. The local mobility anchor MUST create prefix route(s) over the + tunnel to the mobile access gateway for forwarding any traffic + received for the mobile node's home network prefix(es) associated + with that mobility session. The created tunnel and routing state + MUST result in the forwarding behavior on the local mobility + anchor as specified in Section 5.6.2. + + 5. The local mobility anchor MUST send the Proxy Binding + Acknowledgement message with the Status field set to 0 (Proxy + Binding Update Accepted). The message MUST be constructed as + specified in Section 5.3.6. + +5.3.5. Binding De-Registration + + 1. If the received Proxy Binding Update message with the lifetime + value of zero, has a Source Address in the IPv6 header (or the + address in the Alternate Care-of Address option, if the option is + present) different from what is present in the Proxy-CoA field in + the Binding Cache entry, the local mobility anchor MUST ignore + the request. + + 2. Upon accepting the Proxy Binding Update message, with the + lifetime value of zero, the local mobility anchor MUST wait for + MinDelayBeforeBCEDelete amount of time, before it deletes the + + + +Gundavelli, et al. Standards Track [Page 24] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + Binding Cache entry. However, it MUST send the Proxy Binding + Acknowledgement message with the Status field set to 0 (Proxy + Binding Update Accepted). The message MUST be constructed as + specified in Section 5.3.6. + + * During this wait period, the local mobility anchor SHOULD drop + the mobile node's data traffic. + + * During this wait period, if the local mobility anchor receives + a valid Proxy Binding Update message for the same mobility + session with the lifetime value of greater than zero, and if + that request is accepted, then the Binding Cache entry MUST + NOT be deleted, but must be updated with the newly accepted + registration values, and the wait period should be ended. + + * By the end of this wait period, if the local mobility anchor + did not receive any valid Proxy Binding Update messages for + this mobility session, then it MUST delete the Binding Cache + entry and remove the routing state created for that mobility + session. The local mobility anchor can potentially reassign + the prefix(es) associated with this mobility session to other + mobile nodes. + +5.3.6. Constructing the Proxy Binding Acknowledgement Message + + o The local mobility anchor, when sending the Proxy Binding + Acknowledgement message to the mobile access gateway, MUST + construct the message as specified below. + + IPv6 header (src=LMAA, dst=Proxy-CoA) + Mobility header + - BA /* P flag must be set to value of 1 */ + Mobility Options + - Mobile Node Identifier option (mandatory) + - Home Network Prefix option(s) (mandatory) + - Handoff Indicator option (mandatory) + - Access Technology Type option (mandatory) + - Timestamp option (optional) + - Mobile Node Link-layer Identifier option (optional) + - Link-local Address option (optional) + + Figure 6: Proxy Binding Acknowledgement Message Format + + o The Source Address field in the IPv6 header of the message MUST be + set to the destination address of the received Proxy Binding + Update message. + + + + + +Gundavelli, et al. Standards Track [Page 25] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + o The Destination Address field in the IPv6 header of the message + MUST be set to the source address of the received Proxy Binding + Update message. When there is no Alternate Care-of Address option + present in the request, the destination address is the same as the + Proxy-CoA; otherwise, the address may not be the same as the + Proxy-CoA. + + o The Mobile Node Identifier option [RFC4283] MUST be present. The + identifier field in the option MUST be copied from the Mobile Node + Identifier option in the received Proxy Binding Update message. + If the option was not present in the request, the identifier in + the option MUST be set to a zero length identifier. + + o At least one Home Network Prefix option MUST be present. + + * If the Status field is set to a value greater than or equal to + 128, i.e., if the Proxy Binding Update is rejected, all the + Home Network Prefix options that were present in the request + (along with their prefix values) MUST be present in the reply. + But, if there was no Home Network Prefix option present in the + request, then there MUST be only one Home Network Prefix option + with the value in the option set to ALL_ZERO. + + * For all other cases, there MUST be a Home Network Prefix option + for each of the assigned home network prefixes (for that + mobility session), and with the prefix value in the option set + to the allocated prefix value. + + o The Handoff Indicator option MUST be present. The handoff + indicator field in the option MUST be copied from the Handoff + Indicator option in the received Proxy Binding Update message. If + the option was not present in the request, the value in the option + MUST be set to zero. + + o The Access Technology Type option MUST be present. The access + technology type field in the option MUST be copied from the Access + Technology Type option in the received Proxy Binding Update + message. If the option was not present in the request, the value + in the option MUST be set to zero. + + o The Timestamp option MUST be present only if the same option was + present in the received Proxy Binding Update message and MUST NOT + be present otherwise. Considerations from Section 5.5 must be + applied for constructing the Timestamp option. + + o The Mobile Node Link-layer Identifier option MUST be present only + if the same option was present in the received Proxy Binding + Update message and MUST NOT be present otherwise. The link-layer + + + +Gundavelli, et al. Standards Track [Page 26] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + identifier value MUST be copied from the Mobile Node Link-layer + Identifier option present in the received Proxy Binding Update + message. + + o The Link-local Address option MUST be present only if the same + option was present in the received Proxy Binding Update message + and MUST NOT be present otherwise. If the Status field in the + reply is set to a value greater than or equal to 128, i.e., if the + Proxy Binding Update is rejected, then the link-local address from + the request MUST be copied to the Link-local Address option in the + reply, otherwise the following considerations apply. + + * If the received Proxy Binding Update message has the Link-local + Address option with ALL_ZERO value and if there is an existing + Binding Cache entry associated with this request, then the + link-local address from the Binding Cache entry MUST be copied + to the Link-local Address option in the reply. + + * If the received Proxy Binding Update message has the Link-local + Address option with ALL_ZERO value and if there is no existing + Binding Cache entry associated with this request, then the + local mobility anchor MUST generate the link-local address that + the mobile access gateway can use on the point-to-point link + shared with the mobile node. This generated address MUST be + copied to the Link-local Address option in the reply. The same + address MUST also be copied to the link-local address field of + Binding Cache entry created for this mobility session. + + * If the received Proxy Binding Update message has the Link-local + Address option with NON_ZERO value, then the link-local address + from the request MUST be copied to the Link-local Address + option in the reply. The same address MUST also be copied to + the link-local address field of the Binding Cache entry + associated with this request (after creating the Binding Cache + entry, if one does not exist). + + o If IPsec is used for protecting the signaling messages, the + message MUST be protected using the security association existing + between the local mobility anchor and the mobile access gateway. + + o Unlike in Mobile IPv6 [RFC3775], the Type 2 Routing header MUST + NOT be present in the IPv6 header of the packet. + +5.4. Multihoming Support + + This specification allows mobile nodes to connect to a Proxy Mobile + IPv6 domain through multiple interfaces for simultaneous access. The + following are the key aspects of this multihoming support. + + + +Gundavelli, et al. Standards Track [Page 27] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + o When a mobile node connects to a Proxy Mobile IPv6 domain through + multiple interfaces for simultaneous access, the local mobility + anchor MUST allocate a mobility session for each of the attached + interfaces. Each mobility session should be managed under a + separate Binding Cache entry and with its own lifetime. + + o The local mobility anchor MAY allocate more than one home network + prefix for a given interface of the mobile node. However, all the + prefixes associated with a given interface MUST be managed as part + of one mobility session, associated with that interface. + + o The local mobility anchor MUST allow for a handoff between two + different interfaces of a mobile node. In such a scenario, all + the home network prefixes associated with one interface (part of + one mobility session) will be associated with a different + interface of the mobile node. The decision on when to create a + new mobility session and when to update an existing mobility + session MUST be based on the Handover hint present in the Proxy + Binding Update message and under the considerations specified in + this section. + +5.4.1. Binding Cache Entry Lookup Considerations + + There can be multiple Binding Cache entries for a given mobile node. + When doing a lookup for a mobile node's Binding Cache entry for + processing a received Proxy Binding Update message, the local + mobility anchor MUST apply the following multihoming considerations + (in the below specified order, starting with Section 5.4.1.1). These + rules are chained with the processing rules specified in Section 5.3. + +5.4.1.1. Home Network Prefix Option (NON_ZERO Value) Present in the + Request + + +=====================================================================+ + | Registration/De-Registration Message | + +=====================================================================+ + | At least one HNP Option with NON_ZERO Value | + +=====================================================================+ + | ATT | + +=====================================================================+ + | MN-LL-Identifier Opt Present | MN-LL-Identifier Opt Not Present | + +=====================================================================+ + | HI | + +==================================+==================================+ + | BCE Lookup Key: Any of the Home Network Prefixes from the request | + +=====================================================================+ + + Figure 7: Binding Cache Entry (BCE) Lookup Using Home Network Prefix + + + +Gundavelli, et al. Standards Track [Page 28] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + If there is at least one Home Network Prefix option present in the + request with a NON_ZERO prefix value and irrespective of the presence + of the Mobile Node Link-layer Identifier option in the request, the + following considerations MUST be applied. If there is more than one + instance of the Home Network Prefix option, any one of the Home + Network Prefix options present in the request (with NON_ZERO prefix + value) can be used for locating the Binding Cache entry. + + 1. The local mobility anchor MUST verify if there is an existing + Binding Cache entry with one of its home network prefixes + matching the prefix value in one of the Home Network Prefix + options of the received Proxy Binding Update message. + + 2. If a Binding Cache entry does not exist (with one of its home + network prefixes in the Binding Cache entry matching the prefix + value in one of the Home Network Prefix options of the received + Proxy Binding Update message), the request MUST be considered as + a request for creating a new mobility session. + + 3. If there exists a Binding Cache entry (with one of its home + network prefixes in the Binding Cache entry matching the prefix + value in one of the Home Network Prefix options of the received + Proxy Binding Update message), but if the mobile node identifier + in the entry does not match the mobile node identifier in the + Mobile Node Identifier option of the received Proxy Binding + Update message, the local mobility anchor MUST reject the request + with the Status field value set to + NOT_AUTHORIZED_FOR_HOME_NETWORK_PREFIX (mobile node is not + authorized for one or more of the requesting home network + prefixes). + + 4. If there exists a Binding Cache entry (matching MN-Identifier and + one of its home network prefixes in the Binding Cache entry + matching the prefix value in one of the Home Network Prefix + options of the received Proxy Binding Update message), but if all + the prefixes in the request do not match all the prefixes in the + Binding Cache entry, or if they do not match in count, then the + local mobility anchor MUST reject the request with the Status + field value set to BCE_PBU_PREFIX_SET_DO_NOT_MATCH (all the home + network prefixes listed in the BCE do not match all the prefixes + in the received PBU). + + 5. If there exists a Binding Cache entry (matching MN-Identifier and + all the home network prefixes in the Binding Cache entry matching + all the home network prefixes in the received Proxy Binding + Update message) and if any one or more of these below stated + conditions are true, the request MUST be considered as a request + for updating that Binding Cache entry. + + + +Gundavelli, et al. Standards Track [Page 29] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + * If there is a Mobile Node Link-layer Identifier option present + in the request and if the link-layer identifier in the option + matches the link-layer identifier of the Binding Cache entry + and the access technology type in the Access Technology Type + option present in the request matches the access technology + type in the Binding Cache entry. + + * If the Handoff Indicator field in the Handoff Indicator option + present in the request is set to a value of 2 (Handoff between + two different interfaces of the mobile node). + + * If there is no Mobile Node Link-layer Identifier option + present in the request, the link-layer identifier value in the + Binding Cache entry is set to ALL_ZERO, the access technology + type field in the Access Technology Type option present in the + request matches the access technology type in the Binding + Cache entry, and if the Handoff Indicator field in the Handoff + Indicator option present in the request is set to a value of 3 + (Handoff between mobile access gateways for the same + interface). + + * If the Proxy-CoA in the Binding Cache entry matches the source + address of the request (or the address in the Alternate + Care-of Address option, if the option is present) and if the + access technology type field in the Access Technology Type + option present in the request matches the access technology + type in the Binding Cache entry. + + 6. For all other cases, the message MUST be considered as a request + for creating a new mobility session. However, if the received + Proxy Binding Update message has the lifetime value of zero and + if the request cannot be associated with any existing mobility + session, the message MUST be silently ignored. + + + + + + + + + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 30] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +5.4.1.2. Mobile Node Link-layer Identifier Option Present in the + Request + + +=====================================================================+ + | Registration/De-Registration Message | + +=====================================================================+ + | No HNP option with a NON_ZERO Value | + +=====================================================================+ + | ATT | + +=====================================================================+ + | MN-LL-Identifier Option Present (NON_ZERO Value) | + +=====================================================================+ + | HI | + +==================================+==================================+ + | BCE Lookup Keys: (MN-Identifier + ATT + MN-LL-Identifier) | + +=====================================================================+ + + Figure 8: BCE Lookup Using Link-layer Identifier + + If there is no Home Network Prefix option present in the request with + a NON_ZERO prefix value, but if there is a Mobile Node Link-layer + Identifier option present in the request, then the following + considerations MUST be applied for locating the Binding Cache entry. + + 1. The local mobility anchor MUST verify if there is an existing + Binding Cache entry, with the mobile node identifier matching the + identifier in the received Mobile Node Identifier option, access + technology type matching the value in the received Access + Technology Type option, and the link-layer identifier value + matching the identifier in the received Mobile Node Link-layer + Identifier option. + + 2. If there exists a Binding Cache entry (matching MN-Identifier, + Access Technology Type (ATT), and MN-LL-Identifier), the request + MUST be considered as a request for updating that Binding Cache + entry. + + 3. If there does not exist a Binding Cache entry (matching MN- + Identifier, ATT, and MN-LL-Identifier) and the Handoff Indicator + field in the Handoff Indicator option present in the request is + set to a value of 2 (Handoff between two different interfaces of + the mobile node). The local mobility anchor MUST apply the + following additional considerations. + + * The local mobility anchor MUST verify if there exists one and + only one Binding Cache entry with the mobile node identifier + matching the identifier in the Mobile Node Identifier option + present in the request and for any link-layer identifier + + + +Gundavelli, et al. Standards Track [Page 31] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + value. If there exists only one such entry (matching the MN- + Identifier), the request MUST be considered as a request for + updating that Binding Cache entry. + + 4. If there does not exist a Binding Cache entry (matching MN- + Identifier, ATT, and MN-LL-Identifier) and if the Handoff + Indicator field in the Handoff Indicator option present in the + request is set to a value of 4 (Handoff state unknown), the local + mobility anchor MUST apply the following additional + considerations. + + * The local mobility anchor MUST verify if there exists one and + only one Binding Cache entry with the mobile node identifier + matching the identifier in the Mobile Node Identifier option + present in the request and for any link-layer identifier + value. If there exists only one such entry (matching the MN- + Identifier), the local mobility anchor SHOULD wait until the + existing Binding Cache entry is de-registered by the + previously serving mobile access gateway, before the request + can be considered as a request for updating that Binding Cache + entry. However, if there is no de-registration message that + is received within MaxDelayBeforeNewBCEAssign amount of time, + the local mobility anchor, upon accepting the request, MUST + consider the request as a request for creating a new mobility + session. The local mobility anchor MAY also choose to create + a new mobility session without waiting for a de-registration + message, and this should be configurable on the local mobility + anchor. + + 5. For all other cases, the message MUST be considered as a request + for creating a new mobility session. However, if the received + Proxy Binding Update message has the lifetime value of zero and + if the request cannot be associated with any existing mobility + session, the message MUST be silently ignored. + + + + + + + + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 32] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +5.4.1.3. Mobile Node Link-layer Identifier Option Not Present in the + Request + + +=====================================================================+ + | Registration/De-Registration Message | + +=====================================================================+ + | No HNP option with a NON_ZERO Value | + +=====================================================================+ + | ATT | + +=====================================================================+ + | MN-LL-Identifier Option Not Present | + +=====================================================================+ + | HI | + +==================================+==================================+ + | BCE Lookup Key: (MN-Identifier) | + +=====================================================================+ + + Figure 9: BCE Lookup Using Mobile Node Identifier + + If there is no Home Network Prefix option present in the request with + a NON_ZERO prefix value and if there is also no Mobile Node Link- + layer Identifier option present in the request, then the following + considerations MUST be applied for locating the Binding Cache entry. + + 1. The local mobility anchor MUST verify if there exists one and + only one Binding Cache entry with the mobile node identifier + matching the identifier in the Mobile Node Identifier option + present in the request. + + 2. If there exists only one such entry (matching the MN-Identifier) + and the Handoff Indicator field in the Handoff Indicator option + present in the request is set to a value of 2 (Handoff between + two different interfaces of the mobile node) or set to a value of + 3 (Handoff between mobile access gateways for the same + interface), then the request MUST be considered as a request for + updating that Binding Cache entry. + + 3. If there exists only one such entry (matching the MN-Identifier) + and the Handoff Indicator field in the Handoff Indicator option + present in the request is set to a value of 4 (Handoff state + unknown), the local mobility anchor SHOULD wait until the + existing Binding Cache entry is de-registered by the previously + serving mobile access gateway before the request can be + considered as a request for updating that Binding Cache entry. + However, if there is no de-registration message that is received + within MaxDelayBeforeNewBCEAssign amount of time, the local + mobility anchor, upon accepting the request, MUST consider the + request as a request for creating a new mobility session. The + + + +Gundavelli, et al. Standards Track [Page 33] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + local mobility anchor MAY also choose to create a new mobility + session without waiting for a de-registration message, and this + should be configurable on the local mobility anchor. + + 4. For all other cases, the message MUST be considered as a request + for creating a new mobility session. However, if the received + Proxy Binding Update message has the lifetime value of zero and + if the request cannot be associated with any existing mobility + session, the message MUST be silently ignored. + +5.5. Timestamp Option for Message Ordering + + Mobile IPv6 [RFC3775] uses the Sequence Number field in binding + registration messages as a way for the home agent to process the + binding updates in the order they were sent by a mobile node. The + home agent and the mobile node are required to manage this counter + over the lifetime of a binding. However, in Proxy Mobile IPv6, as + the mobile node moves from one mobile access gateway to another and + in the absence of mechanisms such as context transfer between the + mobile access gateways, the serving mobile access gateway will be + unable to determine the sequence number that it needs to use in the + signaling messages. Hence, the sequence number scheme, as specified + in [RFC3775], will be insufficient for Proxy Mobile IPv6. + + If the local mobility anchor cannot determine the sending order of + the received Proxy Binding Update messages, it may potentially + process an older message sent by a mobile access gateway where the + mobile node was previously anchored, but delivered out of order, + resulting in incorrectly updating the mobile node's Binding Cache + entry and creating a routing state for tunneling the mobile node's + traffic to the previous mobile access gateway. + + For solving this problem, this specification adopts two alternative + solutions. One is based on timestamps and the other based on + sequence numbers, as defined in [RFC3775]. + + The basic principle behind the use of timestamps in binding + registration messages is that the node generating the message inserts + the current time of day, and the node receiving the message checks + that this timestamp is greater than all previously accepted + timestamps. The timestamp-based solution may be used when the + serving mobile access gateways in a Proxy Mobile IPv6 domain do not + have the ability to obtain the last sequence number that was sent in + a Proxy Binding Update message for updating a given mobile node's + binding. + + + + + + +Gundavelli, et al. Standards Track [Page 34] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + Clock drift reduces the effectiveness of the timestamp mechanism. + The time required for reconnection is the total of the time required + for the mobile node to roam between two mobile access gateways and + the time required for the serving mobile access gateway to detect the + mobile node on its access link and construct the Proxy Binding Update + message. If the clock skew on any one of these two neighboring + mobile access gateways (relative to the common time source used for + clock synchronization) is more than half this reconnection time, the + timestamp solution will not predictably work in all cases and hence + SHOULD NOT be used. + + As an alternative to the Timestamp-based approach, the specification + also allows the use of Sequence-Number-based scheme, as specified in + [RFC3775]. However, for this scheme to work, the serving mobile + access gateway in a Proxy Mobile IPv6 domain MUST have the ability to + obtain the last sequence number that was sent in a binding + registration message for that mobility session. The sequence number + MUST be maintained on a mobile node's per mobility session basis and + MUST be available to the serving mobile access gateway. This may be + achieved by using context transfer schemes or by maintaining the + sequence number in a policy store. However, the specific details on + how the mobile node's sequence number is made available to the + serving mobile access gateway prior to sending the Proxy Binding + Update message is outside the scope of this document. + + Using the Timestamp-Based Approach: + + 1. A local mobility anchor implementation MUST support the Timestamp + option. If the Timestamp option is present in the received Proxy + Binding Update message, then the local mobility anchor MUST + include a valid Timestamp option in the Proxy Binding + Acknowledgement message that it sends to the mobile access + gateway. + + 2. All the mobility entities in a Proxy Mobile IPv6 domain that are + exchanging binding registration messages using the Timestamp + option MUST have adequately synchronized time-of-day clocks. + This is the essential requirement for this solution to work. If + this requirement is not met, the solution will not predictably + work in all cases. + + 3. The mobility entities in a Proxy Mobile IPv6 domain SHOULD + synchronize their clocks to a common time source. For + synchronizing the clocks, the nodes MAY use the Network Time + Protocol [RFC4330]. Deployments MAY also adopt other approaches + suitable for that specific deployment. Alternatively, if there + is a mobile node generated timestamp that is increasing at every + attachment to the access link and if that timestamp is available + + + +Gundavelli, et al. Standards Track [Page 35] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + to the mobile access gateway (e.g., the Timestamp option in the + SEND [RFC3971] messages that the mobile node sends), the mobile + access gateway can use this timestamp or sequence number in the + Proxy Binding Update messages and does not have to depend on any + external clock source. However, the specific details on how this + is achieved are outside the scope of this document. + + 4. When generating the timestamp value for building the Timestamp + option, the mobility entities MUST ensure that the generated + timestamp is the elapsed time past the same reference epoch, as + specified in the format for the Timestamp option (Section 8.8). + + 5. If the Timestamp option is present in the received Proxy Binding + Update message, the local mobility anchor MUST ignore the + sequence number field in the message. However, it MUST copy the + sequence number from the received Proxy Binding Update message to + the Proxy Binding Acknowledgement message. + + 6. Upon receipt of a Proxy Binding Update message with the Timestamp + option, the local mobility anchor MUST check the timestamp field + for validity. In order for it to be considered valid, the + following MUST be true. + + * The timestamp value contained in the Timestamp option MUST be + close enough (within TimestampValidityWindow amount of time + difference) to the local mobility anchor's time-of-day clock. + However, if the flag MobileNodeGeneratedTimestampInUse is set + to a value of 1, the local mobility anchor MUST ignore this + check and perform only the following check. + + * The timestamp MUST be greater than all previously accepted + timestamps in the Proxy Binding Update messages sent for that + mobile node. + + 7. If the timestamp value in the received Proxy Binding Update is + valid (validity as specified in the above considerations) or if + the flag MobileNodeGeneratedTimestampInUse is set to value of 1, + the local mobility anchor MUST return the same timestamp value in + the Timestamp option included in the Proxy Binding + Acknowledgement message that it sends to the mobile access + gateway. + + 8. If the timestamp value in the received Proxy Binding Update is + lower than the previously accepted timestamp in the Proxy Binding + Update messages sent for that mobility binding, the local + mobility anchor MUST reject the Proxy Binding Update message and + send a Proxy Binding Acknowledgement message with the Status + field set to TIMESTAMP_LOWER_THAN_PREV_ACCEPTED (Timestamp lower + + + +Gundavelli, et al. Standards Track [Page 36] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + than previously accepted timestamp). The message MUST also + include the Timestamp option with the value set to the current + time of day on the local mobility anchor. + + 9. If the timestamp value in the received Proxy Binding Update is + not valid (validity as specified in the above considerations), + the local mobility anchor MUST reject the Proxy Binding Update + and send a Proxy Binding Acknowledgement message with the Status + field set to TIMESTAMP_MISMATCH (Timestamp mismatch). The + message MUST also include the Timestamp option with the value set + to the current time of day on the local mobility anchor. + + Using the Sequence-Number-Based Approach: + + 1. If the Timestamp option is not present in the received Proxy + Binding Update message, the local mobility anchor MUST fall back + to the Sequence-Number-based scheme. It MUST process the + sequence number field as specified in [RFC3775]. Also, it MUST + NOT include the Timestamp option in the Proxy Binding + Acknowledgement messages that it sends to the mobile access + gateway. + + 2. An implementation MUST support the Sequence-Number-based scheme, + as specified in [RFC3775]. + + 3. The Sequence-Number-based approach can be used only when there is + some mechanism (such as context transfer procedure between mobile + access gateways) that allows the serving mobile access gateway to + obtain the last sequence number that was sent in a Proxy Binding + Update message for updating a given mobile node's binding. + +5.6. Routing Considerations + +5.6.1. Bi-Directional Tunnel Management + + The bi-directional tunnel MUST be used for routing the mobile node's + data traffic between the mobile access gateway and the local mobility + anchor. A tunnel hides the topology and enables a mobile node to use + address(es) from its home network prefix(es) from any access link in + that Proxy Mobile IPv6 domain. A tunnel may be created dynamically + when needed and removed when not needed. However, implementations + MAY choose to use static pre-established tunnels instead of + dynamically creating and tearing them down on a need basis. The + following considerations MUST be applied when using dynamically + created tunnels. + + + + + + +Gundavelli, et al. Standards Track [Page 37] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + o A bi-directional tunnel MUST be established between the local + mobility anchor and the mobile access gateway and the local + mobility anchor with IPv6-in-IPv6 encapsulation, as described in + [RFC2473]. The tunnel endpoints are the Proxy-CoA and LMAA. + However, when using IPv4 transport, the endpoints of the tunnel + are IPv4-LMAA and IPv4-Proxy-CoA with the encapsulation mode as + specified in [IPV4-PMIP6]. + + o Implementations MAY use a software timer for managing the tunnel + lifetime and a counter for keeping a count of all the mobile nodes + that are sharing the tunnel. The timer value can be set to the + accepted binding lifetime and can be updated after each periodic + re-registration for extending the lifetime. If the tunnel is + shared for multiple mobile nodes, the tunnel lifetime must be set + to the highest binding lifetime that is granted to any one of + those mobile nodes sharing that tunnel. + + o The tunnel SHOULD be deleted when either the tunnel lifetime + expires or when there are no mobile nodes sharing the tunnel. + +5.6.2. Forwarding Considerations + + Intercepting Packets Sent to the Mobile Node's Home Network: + + o When the local mobility anchor is serving a mobile node, it MUST + be able to receive packets that are sent to the mobile node's home + network. In order for it to receive those packets, it MUST + advertise a connected route in to the Routing Infrastructure for + the mobile node's home network prefix(es) or for an aggregated + prefix with a larger scope. This essentially enables IPv6 routers + in that network to detect the local mobility anchor as the last- + hop router for the mobile node's home network prefix(es). + + Forwarding Packets to the Mobile Node: + + o On receiving a packet from a correspondent node with the + destination address matching a mobile node's home network + prefix(es), the local mobility anchor MUST forward the packet + through the bi-directional tunnel set up for that mobile node. + + o The format of the tunneled packet is shown below. Considerations + from [RFC2473] MUST be applied for IPv6 encapsulation. However, + when using IPv4 transport, the format of the packet is as + described in [IPV4-PMIP6]. + + + + + + + +Gundavelli, et al. Standards Track [Page 38] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + IPv6 header (src= LMAA, dst= Proxy-CoA /* Tunnel Header */ + IPv6 header (src= CN, dst= MN-HOA ) /* Packet Header */ + Upper layer protocols /* Packet Content*/ + + Figure 10: Tunneled Packet from LMA to MAG + + o The format of the tunneled packet is shown below, when payload + protection using IPsec is enabled for the mobile node's data + traffic. However, when using IPv4 transport, the format of the + packet is as described in [IPV4-PMIP6]. + + IPv6 header (src= LMAA, dst= Proxy-CoA /* Tunnel Header */ + ESP Header in tunnel mode /* ESP Header */ + IPv6 header (src= CN, dst= MN-HoA ) /* Packet Header */ + Upper layer protocols /* Packet Content*/ + + Figure 11: Tunneled Packet from LMA to MAG with Payload Protection + + Forwarding Packets Sent by the Mobile Node: + + o All the reverse tunneled packets that the local mobility anchor + received from the mobile access gateway, after removing the tunnel + header MUST be routed to the destination specified in the inner + packet header. These routed packets will have the Source Address + field set to the mobile node's home address. Considerations from + [RFC2473] MUST be applied for IPv6 decapsulation. + +5.6.3. Explicit Congestion Notification (ECN) Considerations for Proxy + Mobile IPv6 Tunnels + + This section describes how the ECN information needs to be handled by + the mobility agents at the tunnel entry and exit points. The ECN + considerations for IP tunnels are specified in [RFC3168], and the + same considerations apply to Proxy Mobile IPv6 tunnels (using IPv6- + in-IPv6 encapsulation mode). Specifically, the full-functionality + option MUST be supported. The relevant ECN considerations from + [RFC3168] are summarized here for convenience. + + Encapsulation Considerations: + + o If the Explicit Congestion Notification (ECN) field in the inner + header is set to ECT(0) or ECT(1), where ECT stands for ECN- + Capable Transport (ECT), the ECN field from the inner header MUST + be copied to the outer header. Additionally, when payload + protection using IPsec is enabled for the mobile node's data + traffic, the ECN considerations from [RFC4301] MUST be applied. + + + + + +Gundavelli, et al. Standards Track [Page 39] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + Decapsulation Considerations: + + o If the Explicit Congestion Notification (ECN) field in the inner + header is set to ECT(0) or ECT(1), and if the ECN field in the + outer header is set to Congestion Experienced (CE), then the ECN + field in the inner header MUST be set to CE. Otherwise, the ECN + field in the inner header MUST NOT be modified. Additionally, + when payload protection using IPsec is enabled for the mobile + node's data traffic, the ECN considerations from [RFC4301] MUST be + applied. + +5.7. Local Mobility Anchor Address Discovery + + Dynamic Home Agent Address Discovery (DHAAD), as explained in Section + 10.5 of [RFC3775], allows a mobile node to discover all the home + agents on its home link by sending an ICMP Home Agent Address + Discovery Request message to the Mobile IPv6 Home Agent's anycast + address, derived from its home network prefix. + + The DHAAD message in the current form cannot be used in Proxy Mobile + IPv6 for discovering the address of the mobile node's local mobility + anchor. In Proxy Mobile IPv6, the local mobility anchor will not be + able to receive any messages sent to the Mobile IPv6 Home Agent's + anycast address corresponding to the mobile node's home network + prefix(es), as the prefix(es) is not hosted on any of its interfaces. + Further, the mobile access gateway will not predictably be able to + locate the serving local mobility anchor that has the mobile node's + binding cache entry. Hence, this specification does not support + Dynamic Home Agent Address Discovery protocol. + + In Proxy Mobile IPv6, the address of the local mobility anchor + configured to serve a mobile node can be discovered by the mobility + access gateway entity via other means. The LMA to be assigned to a + mobile node may be a configured entry in the mobile node's policy + profile, or it may be obtained through mechanisms outside the scope + of this document. + +5.8. Mobile Prefix Discovery Considerations + + This specification does not support mobile prefix discovery. The + mobile prefix discovery mechanism as specified in [RFC3775] is not + applicable to Proxy Mobile IPv6. + + + + + + + + + +Gundavelli, et al. Standards Track [Page 40] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +5.9. Route Optimization Considerations + + The Route Optimization in Mobile IPv6, as defined in [RFC3775], + enables a mobile node to communicate with a correspondent node + directly using its care-of address and further the Return Routability + procedure enables the correspondent node to have reasonable trust + that the mobile node is reachable at both its home address and + care-of address. + + This specification does not support the Route Optimization specified + in Mobile IPv6 [RFC3775]. However, this specification does support + another form of route optimization, as specified in Section 6.10.3. + +6. Mobile Access Gateway Operation + + The Proxy Mobile IPv6 protocol described in this document introduces + a new functional entity, the mobile access gateway (MAG). The mobile + access gateway is the entity that is responsible for detecting the + mobile node's movements to and from the access link and sending the + Proxy Binding Update messages to the local mobility anchor. In + essence, the mobile access gateway performs mobility management on + behalf of a mobile node. + + The mobile access gateway is a function that typically runs on an + access router. However, implementations MAY choose to split this + function and run it across multiple systems. The specifics on how + that is achieved or the signaling interactions between those + functional entities are beyond the scope of this document. + + The mobile access gateway has the following key functional roles: + + o It is responsible for detecting the mobile node's movements on the + access link and for initiating the mobility signaling with the + mobile node's local mobility anchor. + + o Emulation of the mobile node's home link on the access link by + sending Router Advertisement messages containing the mobile node's + home network prefix(es), each prefix carried using the Prefix + Information option [RFC4861]. + + o Responsible for setting up the forwarding for enabling the mobile + node to configure one or more addresses from its home network + prefix(es) and use it from the attached access link. + + + + + + + + +Gundavelli, et al. Standards Track [Page 41] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +6.1. Extensions to Binding Update List Entry Data Structure + + Every mobile access gateway MUST maintain a Binding Update List. + Each entry in the Binding Update List represents a mobile node's + mobility binding with its local mobility anchor. The Binding Update + List is a conceptual data structure, described in Section 11.1 of + [RFC3775]. + + For supporting this specification, the conceptual Binding Update List + entry data structure needs be extended with the following additional + fields. + + o The identifier of the attached mobile node, MN-Identifier. This + identifier is acquired during the mobile node's attachment to the + access link through mechanisms outside the scope of this document. + + o The link-layer identifier of the mobile node's connected + interface. This can be acquired from the received Router + Solicitation messages from the mobile node or during the mobile + node's attachment to the access network. This is typically a + link-layer identifier conveyed by the mobile node; however, the + specific details on how that is conveyed is out of scope for this + specification. If this identifier is not available, this variable + length field MUST be set to two (octets) and MUST be initialized + to a value of ALL_ZERO. + + o A list of IPv6 home network prefixes assigned to the mobile node's + connected interface. The home network prefix(es) may have been + statically configured in the mobile node's policy profile, or, may + have been dynamically allocated by the local mobility anchor. + Each of these prefix entries will also include the corresponding + prefix length. + + o The Link-local address of the mobile access gateway on the access + link shared with the mobile node. + + o The IPv6 address of the local mobility anchor serving the attached + mobile node. This address is acquired from the mobile node's + policy profile or from other means. + + o The interface identifier (if-id) of the point-to-point link + between the mobile node and the mobile access gateway. This is + internal to the mobile access gateway and is used to associate the + Proxy Mobile IPv6 tunnel to the access link where the mobile node + is attached. + + + + + + +Gundavelli, et al. Standards Track [Page 42] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + o The tunnel interface identifier (tunnel-if-id) of the bi- + directional tunnel between the mobile node's local mobility anchor + and the mobile access gateway. This is internal to the mobile + access gateway. The tunnel interface identifier is acquired + during the tunnel creation. + +6.2. Mobile Node's Policy Profile + + A mobile node's policy profile contains the essential operational + parameters that are required by the network entities for managing the + mobile node's mobility service. These policy profiles are stored in + a local or a remote policy store. The mobile access gateway and the + local mobility anchor MUST be able to obtain a mobile node's policy + profile. The policy profile MAY also be handed over to a serving + mobile access gateway as part of a context transfer procedure during + a handoff or the serving mobile access gateway MAY be able to + dynamically generate this profile. The exact details on how this + achieved is outside the scope of this document. However, this + specification requires that a mobile access gateway serving a mobile + node MUST have access to its policy profile. + + The following are the mandatory fields of the policy profile: + + o The mobile node's identifier (MN-Identifier) + + o The IPv6 address of the local mobility anchor (LMAA) + + The following are the optional fields of the policy profile: + + o The mobile node's IPv6 home network prefix(es) assigned to the + mobile node's connected interface. These prefixes have to be + maintained on a per-interface basis. There can be multiple unique + entries for each interface of the mobile node. The specific + details on how the network maintains this association between the + prefix set and the interfaces, specially during the mobility + session handoff between interfaces, is outside the scope of this + document. + + o The mobile node's IPv6 home network Prefix lifetime. This + lifetime will be the same for all the hosted prefixes on the link, + as they all are part of one mobility session. This value can also + be the same for all the mobile node's mobility sessions. + + o Supported address configuration procedures (Stateful, Stateless, + or both) for the mobile node in the Proxy Mobile IPv6 domain + + + + + + +Gundavelli, et al. Standards Track [Page 43] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +6.3. Supported Access Link Types + + This specification supports only point-to-point access link types, + and thus, it assumes that the mobile node and the mobile access + gateway are the only two nodes on the access link. The link is + assumed to have multicast capability. + + This protocol may also be used on other link types, as long as the + link is configured in such a way that it emulates point-to-point + delivery between the mobile node and the mobile access gateway for + all the protocol traffic. + + It is also necessary to be able to identify mobile nodes attaching to + the link. Requirements relating to this are covered in Section 6.6. + + Finally, while this specification can operate without link-layer + indications of node attachment and detachment to the link, the + existence of such indications either on the network or mobile node + side improves the resulting performance. + +6.4. Supported Address Configuration Modes + + A mobile node in the Proxy Mobile IPv6 domain can configure one or + more global IPv6 addresses on its interface (using Stateless, + Stateful address autoconfiguration procedures or manual address + configuration) from the hosted prefix(es) on that link. The Router + Advertisement messages sent on the access link specify the address + configuration methods permitted on that access link for that mobile + node. However, the advertised flags, with respect to the address + configuration, will be consistent for a mobile node, on any of the + access links in that Proxy Mobile IPv6 domain. Typically, these + configuration settings will be based on the domain-wide policy or + based on a policy specific to each mobile node. + + When stateless address autoconfiguration is supported on the access + link, the mobile node can generate one or more IPv6 addresses from + the hosted prefix(es) by standard IPv6 mechanisms such as Stateless + Autoconfiguration [RFC4862] or Privacy extensions [RFC4941]. + + When stateful address autoconfiguration is supported on the link, the + mobile node can obtain the address configuration from the DHCP server + located in the Proxy Mobile IPv6 domain, by standard DHCP mechanisms, + as specified in [RFC3315]. The obtained address(es) will be from its + home network prefix(es). Section 6.11 specifies the details on how + this configuration can be achieved. + + + + + + +Gundavelli, et al. Standards Track [Page 44] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + Additionally, other address configuration mechanisms specific to the + access link between the mobile node and the mobile access gateway may + also be used for delivering the address configuration to the mobile + node. This specification does not modify the behavior of any of the + standard IPv6 address configuration mechanisms. + +6.5. Access Authentication and Mobile Node Identification + + When a mobile node attaches to an access link connected to the mobile + access gateway, the deployed access security protocols on that link + SHOULD ensure that the network-based mobility management service is + offered only after authenticating and authorizing the mobile node for + that service. The exact specifics on how this is achieved or the + interactions between the mobile access gateway and the access + security service are outside the scope of this document. This + specification goes with the stated assumption of having an + established trust between the mobile node and the mobile access + gateway before the protocol operation begins. + +6.6. Acquiring Mobile Node's Identifier + + All the network entities in a Proxy Mobile IPv6 domain MUST be able + to identify a mobile node, using its MN-Identifier. This identifier + MUST be stable and unique across the Proxy Mobile IPv6 domain. The + mobility entities in the Proxy Mobile IPv6 domain MUST be able to use + this identifier in the signaling messages and unambiguously identify + a given mobile node. The following are some of the considerations + related to this MN-Identifier. + + o The MN-Identifier is typically obtained as part of the access + authentication or from a notified network attachment event. In + cases where the user identifier authenticated during access + authentication uniquely identifies a mobile node, the MN- + Identifier MAY be the same as the user identifier. However, the + user identifier MUST NOT be used if it identifies a user account + that can be used from more than one mobile node operating in the + same Proxy Mobile IPv6 domain. + + o In some cases, the obtained identifier, as part of the access + authentication, can be a temporary identifier and further that + temporary identifier may be different at each re-authentication. + However, the mobile access gateway MUST be able to use this + temporary identifier and obtain the mobile node's stable + identifier from the policy store. For instance, in AAA-based + systems, the Remote Authentication Dial-In User Service (RADIUS) + attribute, Chargeable-User-Identifier [RFC4372] may be used, as + long as it uniquely identifies a mobile node, and not a user + account that can be used with multiple mobile nodes. + + + +Gundavelli, et al. Standards Track [Page 45] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + o In some cases and for privacy reasons, the MN-Identifier that the + policy store delivers to the mobile access gateway may not be the + true identifier of the mobile node. However, the mobility access + gateway MUST be able to use this identifier in the signaling + messages exchanged with the local mobility anchor. + + o The mobile access gateway MUST be able to identify the mobile node + by its MN-Identifier, and it MUST be able to associate this + identity to the point-to-point link shared with the mobile node. + +6.7. Home Network Emulation + + One of the key functions of a mobile access gateway is to emulate the + mobile node's home network on the access link. It must ensure the + mobile node does not detect any change with respect to its layer-3 + attachment even after it changes its point of attachment in that + Proxy Mobile IPv6 domain. + + For emulating the mobile node's home link on the access link, the + mobile access gateway must be able to send Router Advertisement + messages advertising the mobile node's home network prefix(es) + carried using the Prefix Information option(s) [RFC4861] and with + other address configuration parameters consistent with its home link + properties. Typically, these configuration settings will be based on + the domain-wide policy or based on a policy specific to each mobile + node. + + Typically, the mobile access gateway learns the mobile node's home + network prefix(es) details from the received Proxy Binding + Acknowledgement message, or it may obtain them from the mobile node's + policy profile. However, the mobile access gateway SHOULD send the + Router Advertisements advertising the mobile node's home network + prefix(es) only after successfully completing the binding + registration with the mobile node's local mobility anchor. + + When advertising the home network prefix(es) in the Router + Advertisement messages, the mobile access gateway MAY set the prefix + lifetime value for the advertised prefix(es) to any chosen value at + its own discretion. An implementation MAY choose to tie the prefix + lifetime to the mobile node's binding lifetime. The prefix lifetime + can also be an optional configuration parameter in the mobile node's + policy profile. + +6.8. Link-local and Global Address Uniqueness + + A mobile node in the Proxy Mobile IPv6 domain, as it moves from one + mobile access gateway to the other, will continue to detect its home + network and does not detect a change of layer-3 attachment. Every + + + +Gundavelli, et al. Standards Track [Page 46] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + time the mobile node attaches to a new link, the event related to the + interface state change will trigger the mobile node to perform + Duplicate Address Detection (DAD) operation on the link-local and + global address(es). However, if the mobile node is Detecting Network + Attachment in IPv6 (DNAv6) enabled, as specified in [DNAV6], it may + not detect the link change due to DNAv6 optimizations and may not + trigger the duplicate address detection (DAD) procedure for its + existing addresses, which may potentially lead to address collisions + after the mobile node's handoff to a new link. + + The issue of address collision is not relevant to the mobile node's + global address(es). Since the assigned home network prefix(es) are + for the mobile node's exclusive usage, no other node shares an + address (other than Subnet-Router anycast address that is configured + by the mobile access gateway) from the prefix(es), and so the + uniqueness for the mobile node's global address is assured on the + access link. + + The issue of address collision is however relevant to the mobile + node's link-local addresses since the mobile access gateway and the + mobile node will have link-local addresses configured from the same + link-local prefix (FE80::/64). This leaves a room for link-local + address collision between the two neighbors (i.e., the mobile node + and the mobile access gateway) on that access link. For solving this + problem, this specification requires that the link-local address that + the mobile access gateway configures on the point-to-point link + shared with a given mobile node be generated by the local mobility + anchor and be stored in the mobile node's Binding Cache entry. This + address will not change for the duration of that mobile node's + mobility session and can be provided to the serving mobile access + gateway at every mobile node's handoff, as part of the Proxy Mobile + IPv6 signaling messages. The specific method by which the local + mobility anchor generates the link-local address is out of scope for + this specification. + + It is highly desirable that the access link on the mobile access + gateway shared with the mobile node be provisioned in such a way that + before the mobile node completes the DAD operation [RFC4862] on its + link-local address, the mobile access gateway on that link is aware + of its own link-local address provided by the local mobility anchor + that it needs to use on that access link. This essentially requires + a successful completion of the Proxy Mobile IPv6 signaling by the + mobile access gateway before the mobile node completes the DAD + operation. This can be achieved by ensuring that link-layer + attachment does not complete until the Proxy Mobile IPv6 signaling is + + + + + + +Gundavelli, et al. Standards Track [Page 47] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + completed. Alternatively, network and local mobility anchor capacity + and signaling retransmission timers can be provisioned in such a way + that signaling is likely to complete during the default waiting + period associated with the DAD process. + + Optionally, implementations MAY choose to configure a fixed link- + local address across all the access links in a Proxy Mobile IPv6 + domain and without a need for carrying this address from the local + mobility anchor to the mobile access gateway in the Proxy Mobile IPv6 + signaling messages. The configuration variable + FixedMAGLinkLocalAddressOnAllAccessLinks determines the enabled mode + in that Proxy Mobile IPv6 domain. + +6.9. Signaling Considerations + +6.9.1. Binding Registrations + +6.9.1.1. Mobile Node Attachment and Initial Binding Registration + + 1. After detecting a new mobile node on its access link, the mobile + access gateway MUST identify the mobile node and acquire its MN- + Identifier. If it determines that the network-based mobility + management service needs to be offered to the mobile node, it + MUST send a Proxy Binding Update message to the local mobility + anchor. + + 2. The Proxy Binding Update message MUST include the Mobile Node + Identifier option [RFC4283], carrying the MN-Identifier for + identifying the mobile node. + + 3. The Home Network Prefix option(s) MUST be present in the Proxy + Binding Update message. If the mobile access gateway learns the + mobile node's home network prefix(es) either from its policy + store or from other means, the mobile access gateway MAY choose + to request the local mobility anchor to allocate the specific + prefix(es) by including a Home Network Prefix option for each of + those requested prefixes. The mobile access gateway MAY also + choose to include just one Home Network Prefix option with the + prefix value of ALL_ZERO, for requesting the local mobility + anchor to do the prefix assignment. However, when including a + Home Network Prefix option with the prefix value of ALL_ZERO, + there MUST be only one instance of the Home Network prefix + option in the request. + + 4. The Handoff Indicator option MUST be present in the Proxy + Binding Update message. The Handoff Indicator field in the + Handoff Indicator option MUST be set to a value indicating the + handoff hint. + + + +Gundavelli, et al. Standards Track [Page 48] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + * The Handoff Indicator field MUST be set to a value of 1 + (Attachment over a new interface) if the mobile access + gateway determines (under the Handoff Indicator + considerations specified in this section) that the mobile + node's current attachment to the network over this interface + is not as a result of a handoff of an existing mobility + session (over the same interface or through a different + interface), but as a result of an attachment over a new + interface. This essentially serves as a request to the local + mobility anchor to create a new mobility session and not + update any existing Binding Cache entry created for the same + mobile node connected to the Proxy Mobile IPv6 domain through + a different interface. + + * The Handoff Indicator field MUST be set to a value of 2 + (Handoff between two different interfaces of the mobile node) + if the mobile access gateway definitively knows the mobile + node's current attachment is due to a handoff of an existing + mobility session between two different interfaces of the + mobile node. + + * The Handoff Indicator field MUST be set to a value of 3 + (Handoff between mobile access gateways for the same + interface) if the mobile access gateway definitively knows + the mobile node's current attachment is due to a handoff of + an existing mobility session between two mobile access + gateways and for the same interface of the mobile node. + + * The Handoff Indicator field MUST be set to a value of 4 + (Handoff state unknown) if the mobile access gateway cannot + determine if the mobile node's current attachment is due to a + handoff of an existing mobility session. + + 5. The mobile access gateway MUST apply the below considerations + when choosing the value for the Handoff Indicator field. + + * The mobile access gateway can choose to use the value 2 + (Handoff between two different interfaces of the mobile + node), only when it knows that the mobile node has, on + purpose, switched from one interface to another, and the + previous interface is going to be disabled. It may know this + due to a number of factors. For instance, most cellular + networks have controlled handovers where the network knows + that the host is moving from one attachment to another. In + this situation, the link-layer mechanism can inform the + mobility functions that this is indeed a movement, not a new + attachment. + + + + +Gundavelli, et al. Standards Track [Page 49] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + * Some link layers have link-layer identifiers that can be used + to distinguish (a) the movement of a particular interface to + a new attachment from (b) the attachment of a new interface + from the same host. Option value 3 (Handoff between mobile + access gateways for the same interface) is appropriate in + case (a) and a value of 1 (Attachment over a new interface) + in case (b). + + * The mobile access gateway MUST NOT set the option value to 2 + (Handoff between two different interfaces of the mobile node) + or 3 (Handoff between mobile access gateways for the same + interface) if it cannot be determined that the mobile node + can move the address between the interfaces involved in the + handover or that it is the same interface that has moved. + Otherwise, Proxy Mobile IPv6-unaware hosts that have multiple + physical interfaces to the same domain may suffer unexpected + failures. + + * Where no support from the link layer exists, the host and the + network would need to inform each other about the intended + movement. The Proxy Mobile IPv6 protocol does not specify + this and simply requires that knowledge about movements can + be derived either from the link-layer or from somewhere else. + The method by which this is accomplished is outside the scope + of this specification. + + 6. Either the Timestamp option or a valid sequence number + maintained on a per mobile node's mobility session basis as + specified in [RFC3775] (if the Sequence-Number-based scheme is + in use) MUST be present. This can be determined based on the + value of the configuration flag TimestampBasedApproachInUse. + When Timestamp option is added to the message, the mobile access + gateway SHOULD also set the Sequence Number field to a value of + a monotonically increasing counter (maintained at each mobile + access gateway and not to be confused with the per mobile node + sequence number specified in [RFC3775]). The local mobility + anchor will ignore this field when there is a Timestamp option + present in the request, but will return the same value in the + Proxy Binding Acknowledgement message. This will be useful for + matching the reply to the request message. + + 7. The Mobile Node Link-layer Identifier option carrying the link- + layer identifier of the currently attached interface MUST be + present in the Proxy Binding Update message, if the mobile + access gateway is aware of the same. If the link-layer + identifier of the currently attached interface is not known or + if the identifier value is ALL_ZERO, this option MUST NOT be + present. + + + +Gundavelli, et al. Standards Track [Page 50] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + 8. The Access Technology Type option MUST be present in the Proxy + Binding Update message. The access technology type field in the + option SHOULD be set to the type of access technology by which + the mobile node is currently attached to the mobile access + gateway. + + 9. The Link-local Address option MUST be present in the Proxy + Binding Update message only if the value of the configuration + variable FixedMAGLinkLocalAddressOnAllAccessLinks is set to a + value of ALL_ZERO; otherwise, the Link-local Address option MUST + NOT be present in the request. Considerations from Section 6.8 + MUST be applied when using the Link-local Address option. + + * For querying the local mobility anchor to provide the link- + local address that it should use on the point-to-point link + shared with the mobile node, this option MUST be set to + ALL_ZERO value. This essentially serves as a request to the + local mobility anchor to provide the link-local address that + it can use on the access link shared with the mobile node. + + 10. The Proxy Binding Update message MUST be constructed as + specified in Section 6.9.1.5. + + 11. If there is no existing Binding Update List entry for that + mobile node, the mobile access gateway MUST create a Binding + Update List entry for the mobile node upon sending the Proxy + Binding Update message. + +6.9.1.2. Receiving Proxy Binding Acknowledgement + + On receiving a Proxy Binding Acknowledgement message (format + specified in Section 8.2) from the local mobility anchor, the mobile + access gateway MUST process the message as specified below. + + 1. The received Proxy Binding Acknowledgement message (a Binding + Acknowledgement message with the (P) flag set to value of 1) + MUST be authenticated as described in Section 4. When IPsec is + used for message authentication, the SPI in the IPsec header + [RFC4306] of the received packet is needed for locating the + security association, for authenticating the Proxy Binding + Acknowledgement message. + + 2. The mobile access gateway MUST observe the rules described in + Section 9.2 of [RFC3775] when processing Mobility Headers in the + received Proxy Binding Acknowledgement message. + + + + + + +Gundavelli, et al. Standards Track [Page 51] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + 3. The mobile access gateway MUST apply the considerations + specified in Section 5.5 for processing the Sequence Number + field and the Timestamp option (if present) in the message. + + 4. The mobile access gateway MUST ignore any checks, specified in + [RFC3775], related to the presence of a Type 2 Routing header in + the Proxy Binding Acknowledgement message. + + 5. The mobile access gateway MAY use the mobile node identifier + present in the Mobile Node Identifier option for matching the + response to the request messages that it sent recently. + However, if there is more than one request message in its + request queue for the same mobile node, the sequence number + field can be used for identifying the exact message from those + messages. There are other ways to achieve this and + implementations are free to adopt the best approach that suits + their implementation. Additionally, if the received Proxy + Binding Acknowledgement message does not match any of the Proxy + Binding Update messages that it sent recently, the message MUST + be ignored. + + 6. If the received Proxy Binding Acknowledgement message has any + one or more of the following options, Handoff Indicator option, + Access Technology Type option, Mobile Node Link-layer Identifier + option, Mobile Node Identifier option, carrying option values + that are different from the option values present in the + corresponding request (Proxy Binding Update) message, the + message MUST be ignored as the local mobility anchor is expected + to echo back all these listed options and with the same option + values in the reply message. In this case, the mobile access + gateway MUST NOT retransmit the Proxy Binding Update message + until an administrative action is taken. + + 7. If the received Proxy Binding Acknowledgement message has the + Status field value set to PROXY_REG_NOT_ENABLED (Proxy + registration not enabled for the mobile node), the mobile access + gateway SHOULD NOT send a Proxy Binding Update message again for + that mobile node until an administrative action is taken. It + MUST deny the mobility service to that mobile node. + + 8. If the received Proxy Binding Acknowledgement message has the + Status field value set to TIMESTAMP_LOWER_THAN_PREV_ACCEPTED + (Timestamp value lower than previously accepted value), the + mobile access gateway SHOULD try to register again to reassert + the mobile node's presence on its access link. The mobile + access gateway is not specifically required to synchronize its + clock upon receiving this error code. + + + + +Gundavelli, et al. Standards Track [Page 52] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + 9. If the received Proxy Binding Acknowledgement message has the + Status field value set to TIMESTAMP_MISMATCH (Invalid timestamp + value), the mobile access gateway SHOULD try to register again + only after it has synchronized its clock to a common time source + that is used by all the mobility entities in that domain for + their clock synchronization. The mobile access gateway SHOULD + NOT synchronize its clock to the local mobility anchor's system + clock, based on the timestamp present in the received message. + + 10. If the received Proxy Binding Acknowledgement message has the + Status field value set to NOT_AUTHORIZED_FOR_HOME_NETWORK_PREFIX + (The mobile node is not authorized for one or more of the + requesting home network prefixes), the mobile access gateway + SHOULD NOT request the same prefix(es) again, but MAY request + the local mobility anchor to do the assignment of prefix(es) by + including only one Home Network Prefix option with the prefix + value set to ALL_ZERO. + + 11. If the received Proxy Binding Acknowledgement message has the + Status field value set to any value greater than or equal to 128 + (i.e., if the binding is rejected), the mobile access gateway + MUST NOT advertise the mobile node's home network prefix(es) in + the Router Advertisement messages sent on that access link and + MUST deny the mobility service to the mobile node by not + forwarding any packets received from the mobile node using an + address from the home network prefix(es). It MAY also tear down + the point-to-point link shared with the mobile node. + + 12. If the received Proxy Binding Acknowledgement message has the + Status field value set to 0 (Proxy Binding Update accepted), the + mobile access gateway MUST establish a bi-directional tunnel to + the local mobility anchor (if there is no existing bi- + directional tunnel to that local mobility anchor). + Considerations from Section 5.6.1 MUST be applied for managing + the dynamically created bi-directional tunnel. + + 13. The mobile access gateway MUST set up the route for forwarding + the packets received from the mobile node using address(es) from + its home network prefix(es) through the bi-directional setup for + that mobile node. The created tunnel and the routing state MUST + result in the forwarding behavior on the mobile access gateway + as specified in Section 6.10.5. + + 14. The mobile access gateway MUST also update the Binding Update + List entry to reflect the accepted binding registration values. + It MUST also advertise the mobile node's home network prefix(es) + as the hosted on-link prefixes, by including them in the Router + Advertisement messages that it sends on that access link. + + + +Gundavelli, et al. Standards Track [Page 53] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + 15. If the received Proxy Binding Acknowledgement message has the + address in the Link-local Address option set to a NON_ZERO + value, the mobile access gateway SHOULD configure that link- + local address on that point-to-point link and SHOULD NOT + configure any other link-local address without performing a DAD + operation [RFC4862]. This will avoid any potential link-local + address collisions on that access link. However, if the link- + local address generated by the local mobility anchor happens to + be already in use by the mobile node on that link, the mobile + access gateway MUST NOT use that address, but SHOULD configure a + different link-local address. It SHOULD also upload this link- + local address to the local mobility anchor by immediately + sending a Proxy Binding Update message and by including this + address in the Link-local Address option. + +6.9.1.3. Extending Binding Lifetime + + 1. For extending the lifetime of a currently registered mobile node + (i.e., after a successful initial binding registration from the + same mobile access gateway), the mobile access gateway can send a + Proxy Binding Update message to the local mobility anchor with a + new lifetime value. This re-registration message MUST be + constructed with the same set of options as the initial Proxy + Binding Update message, under the considerations specified in + Section 6.9.1.1. However, the following exceptions apply. + + 2. There MUST be a Home Network Prefix option for each of the + assigned home network prefixes assigned for that mobility session + and with the prefix value in the option set to that respective + prefix value. + + 3. The Handoff Indicator field in the Handoff Indicator option MUST + be set to a value of 5 (Handoff state not changed - Re- + Registration). + +6.9.1.4. Mobile Node Detachment and Binding De-Registration + + 1. If at any point the mobile access gateway detects that the mobile + node has moved away from its access link, or if it decides to + terminate the mobile node's mobility session, it SHOULD send a + Proxy Binding Update message to the local mobility anchor with + the lifetime value set to zero. This de-registration message + MUST be constructed with the same set of options as the initial + Proxy Binding Update message, under the considerations specified + in Section 6.9.1.1. However, the following exceptions apply. + + + + + + +Gundavelli, et al. Standards Track [Page 54] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + 2. There MUST be a Home Network Prefix option for each of the + assigned home network prefixes assigned for that mobility session + and with the prefix value in the option set to the respective + prefix value. + + 3. The Handoff Indicator field in the Handoff Indicator option MUST + be set to a value of 4 (Handoff state unknown). + + Either upon receipt of a Proxy Binding Acknowledgement message from + the local mobility anchor with the Status field set to 0 (Proxy + Binding Update Accepted), or after INITIAL_BINDACK_TIMEOUT [RFC3775] + timeout waiting for the reply, the mobile access gateway MUST do the + following: + + 1. It MUST remove the Binding Update List entry for the mobile node + from its Binding Update List. + + 2. It MUST remove the created routing state for tunneling the mobile + node's traffic. + + 3. If there is a dynamically created tunnel to the mobile node's + local mobility anchor and if there are not other mobile nodes for + which the tunnel is being used, then the tunnel MUST be deleted. + + 4. It MUST tear down the point-to-point link shared with the mobile + node. This action will force the mobile node to remove any IPv6 + address configuration on the interface connected to this point- + to-point link. + +6.9.1.5. Constructing the Proxy Binding Update Message + + o The mobile access gateway, when sending the Proxy Binding Update + message to the local mobility anchor, MUST construct the message + as specified below. + + IPv6 header (src=Proxy-CoA, dst=LMAA) + Mobility header + - BU /* P & A flags MUST be set to value 1 */ + Mobility Options + - Mobile Node Identifier option (mandatory) + - Home Network Prefix option(s) (mandatory) + - Handoff Indicator option (mandatory) + - Access Technology Type option (mandatory) + - Timestamp option (optional) + - Mobile Node Link-layer Identifier option (optional) + - Link-local Address option (optional) + + Figure 12: Proxy Binding Update Message Format + + + +Gundavelli, et al. Standards Track [Page 55] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + o The Source Address field in the IPv6 header of the message MUST be + set to the global address configured on the egress interface of + the mobile access gateway. When there is no Alternate Care-of + Address option present in the request, this address will be + considered as the Proxy-CoA for this Proxy Binding Update message. + However, when there is an Alternate Care-of Address option present + in the request, this address will be not be considered as the + Proxy-CoA, but the address in the Alternate Care-of Address option + will be considered as the Proxy-CoA. + + o The Destination Address field in the IPv6 header of the message + MUST be set to the local mobility anchor address. + + o The Mobile Node Identifier option [RFC4283] MUST be present. + + o At least one Home Network Prefix option MUST be present. + + o The Handoff Indicator option MUST be present. + + o The Access Technology Type option MUST be present. + + o The Timestamp option MAY be present. + + o The Mobile Node Link-layer Identifier option MAY be present. + + o The Link-local Address option MAY be present. + + o If IPsec is used for protecting the signaling messages, the + message MUST be protected, using the security association existing + between the local mobility anchor and the mobile access gateway. + + o Unlike in Mobile IPv6 [RFC3775], the Home Address option [RFC3775] + MUST NOT be present in the IPv6 Destination Options extension + header of the Proxy Binding Update message. + +6.9.2. Router Solicitation Messages + + A mobile node may send a Router Solicitation message on the access + link shared with the mobile access gateway. The Router Solicitation + message that the mobile node sends is as specified in [RFC4861]. The + mobile access gateway, on receiving the Router Solicitation message + or before sending a Router Advertisement message, MUST apply the + following considerations. + + 1. The mobile access gateway, on receiving the Router Solicitation + message, SHOULD send a Router Advertisement message containing + the mobile node's home network prefix(es) as the on-link + prefix(es). However, before sending the Router Advertisement + + + +Gundavelli, et al. Standards Track [Page 56] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + message containing the mobile node's home network prefix(es), it + SHOULD complete the binding registration process with the mobile + node's local mobility anchor. + + 2. If the local mobility anchor rejects the Proxy Binding Update + message, or, if the mobile access gateway failed to complete the + binding registration process for whatever reason, the mobile + access gateway MUST NOT advertise the mobile node's home network + prefix(es) in the Router Advertisement messages that it sends on + the access link. However, it MAY choose to advertise a local + visited network prefix to enable the mobile node for regular IPv6 + access. + + 3. The mobile access gateway SHOULD add the MTU option, as specified + in [RFC4861], to the Router Advertisement messages that it sends + on the access link. This will ensure the mobile node on the link + uses the advertised MTU value. The MTU value SHOULD reflect the + tunnel MTU for the bi-directional tunnel between the mobile + access gateway and the local mobility anchor. Considerations + from Section 6.9.5 SHOULD be applied for determining the tunnel + MTU value. + +6.9.3. Default-Router + + In Proxy Mobile IPv6, the mobile access gateway is the IPv6 default- + router for the mobile node on the access link. However, as the + mobile node moves from one access link to another, the serving mobile + access gateway on those respective links will send the Router + Advertisement messages. If these Router Advertisements are sent + using a different link-local address or a different link-layer + address, the mobile node will always detect a new default-router + after every handoff. For solving this problem, this specification + requires all the mobile access gateways in the Proxy Mobile IPv6 + domain to use the same link-local and link-layer address on any of + the access links wherever the mobile node attaches. These addresses + can be fixed addresses across the entire Proxy Mobile IPv6 domain, + and all the mobile access gateways can use these globally fixed + address on any of the point-to-point links. The configuration + variables FixedMAGLinkLocalAddressOnAllAccessLinks and + FixedMAGLinkLayerAddressOnAllAccessLinks SHOULD be used for this + purpose. Additionally, this specification allows the local mobility + anchor to generate the link-local address and provide it to the + mobile access gateway as part of the signaling messages. + + However, both of these approaches (a link-local address generated by + the local mobility anchor or when using a globally fixed link-local + address) have implications on the deployment of SEcure Neighbor + Discovery (SEND) [RFC3971]. In SEND, routers have certificates and + + + +Gundavelli, et al. Standards Track [Page 57] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + public key pairs, and their Router Advertisements are signed with the + private keys of these key pairs. When a number of different routers + use the same addresses, the routers either all have to be able to + construct these signatures for the same key pair, or the used key + pair and the router's cryptographic identity must change after a + movement. Both approaches are problematic. Sharing of private key + information across multiple nodes in a PMIP6 domain is poor design + from a security perspective. And changing even the cryptographic + identity of the router goes against the general idea of the Proxy + Mobile IPv6 being as invisible to the hosts as possible. + + There is, however, ongoing work in the IETF to revise the SEND + specifications. It is suggested that these revisions also address + the above problem. Other revisions are needed to deal with other + problematic cases (such as Neighbor Discovery proxies) before wide- + spread deployment of SEND. + +6.9.4. Retransmissions and Rate Limiting + + The mobile access gateway is responsible for retransmissions and rate + limiting the Proxy Binding Update messages that it sends to the local + mobility anchor. The Retransmission and the Rate Limiting rules are + as specified in [RFC3775]. However, the following considerations + MUST be applied. + + 1. When the mobile access gateway sends a Proxy Binding Update + message, it should use the constant, INITIAL_BINDACK_TIMEOUT + [RFC3775], for configuring the retransmission timer, as specified + in Section 11.8 [RFC3775]. However, the mobile access gateway is + not required to use a longer retransmission interval of + InitialBindackTimeoutFirstReg, as specified in [RFC3775], for the + initial Proxy Binding Update message. + + 2. If the mobile access gateway fails to receive a valid matching + response for a registration or re-registration message within the + retransmission interval, it SHOULD retransmit the message until a + response is received. However, the mobile access gateway MUST + ensure the mobile node is still attached to the connected link + before retransmitting the message. + + 3. As specified in Section 11.8 of [RFC3775], the mobile access + gateway MUST use an exponential back-off process in which the + timeout period is doubled upon each retransmission, until either + the node receives a response or the timeout period reaches the + value MAX_BINDACK_TIMEOUT [RFC3775]. The mobile access gateway + MAY continue to send these messages at this slower rate + indefinitely. + + + + +Gundavelli, et al. Standards Track [Page 58] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + 4. If the Timestamp-based scheme is in use, the retransmitted Proxy + Binding Update messages MUST use the latest timestamp. If the + Sequence Number scheme is in use, the retransmitted Proxy Binding + Update messages MUST use a Sequence Number value greater than + that was used for the previous transmission of this Proxy Binding + Update message, just as specified in [RFC3775]. + +6.9.5. Path MTU Discovery + + It is important that mobile node, mobile access gateway, and local + mobility anchor have a correct understanding of MTUs. When the + mobile node uses the correct MTU, it can send packets that do not + exceed the local link MTU and do not cause the tunneled packets from + the mobile access gateway to be fragmented. This is important both + from the perspective of efficiency, as well as preventing hard-to- + diagnose MTU problems. The following are some of the considerations + related to Path MTU discovery. + + o The local mobility anchor and mobile access gateway MAY use the + Path MTU discovery mechanisms, as specified in [RFC1981] or in + [RFC4821], for determining the Path MTU (PMTU) for the (LMA-MAG) + paths. The specific discovery mechanism to be used in a given + deployment can be configurable. + + o The mobility entities MUST implement and SHOULD support ICMP-based + Path MTU discovery mechanism, as specified in [RFC1981]. However, + this mechanism may not work correctly if the Proxy Mobile IPv6 + network does not deliver or process ICMP Packet Too Big messages. + + o The mobility entities MAY implement Packetization Layer Path MTU + discovery mechanisms, as specified in [RFC4821], and use any + application traffic as a payload for the PMTU discovery. Neither + the Proxy Mobile IPv6 protocol or the tunnel between the mobile + access gateway and local mobility agent can easily be used for + this purpose. However, implementations SHOULD support at least + the use of an explicit ICMP Echo Request/Response for this + purpose. + + o The mobility entities MAY choose to perform Path MTU discovery for + all the (LMA-MAG) paths at the boot time and may repeat this + operation periodically to ensure the Path MTU values have not + changed for those paths. If the dynamic PMTU discovery mechanisms + fail to determine the Path MTU, an administratively configured + default value MUST be used. + + + + + + + +Gundavelli, et al. Standards Track [Page 59] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + o The IPv6 tunnel MTU for an established tunnel between the local + mobility anchor and the mobile access gateway MUST be computed + based on the determined Path MTU value for that specific path and + the computation should be as specified in Section 6.7 of + [RFC2473]. + + o The mobile access gateway SHOULD use the determined tunnel Path + MTU value (for the tunnel established with the mobile node's local + mobility anchor) as the MTU value in the MTU option that it sends + in the Router Advertisements on the access link shared with the + mobile node. But, if the MTU value of the access link shared with + the mobile node is lower than the determined Path MTU value, then + the MTU of the access link MUST be used in the MTU option. + + o If the mobile access gateway detects a change in the MTU value for + any of the paths (LMA-MAG) and at any point of time, the + corresponding tunnel MTU value MUST be updated to reflect the + change in Path MTU value. The adjusted tunnel MTU value (lower of + the Path MTU and the access link MTU) SHOULD be notified to the + impacted mobile nodes by sending additional Router Advertisement + messages. Additionally, the adjusted tunnel MTU value MUST be + used in all the subsequent Router Advertisement messages as well. + +6.10. Routing Considerations + + This section describes how the mobile access gateway handles the + traffic to/from the mobile node that is attached to one of its access + interfaces. + + Proxy-CoA LMAA + | | + +--+ +---+ +---+ +--+ + |MN|----------|MAG|======================|LMA|----------|CN| + +--+ +---+ +---+ +--+ + IPv6 Tunnel + + Figure 13: Proxy Mobile IPv6 Tunnel + +6.10.1. Transport Network + + As per this specification, the transport network between the local + mobility anchor and the mobile access gateway is an IPv6 network. + The document [IPV4-PMIP6] specifies the required extensions for + negotiating IPv4 transport and the corresponding encapsulation mode. + + + + + + + +Gundavelli, et al. Standards Track [Page 60] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +6.10.2. Tunneling and Encapsulation Modes + + An IPv6 address that a mobile node uses from its home network + prefix(es) is topologically anchored at the local mobility anchor. + For a mobile node to use this address from an access network attached + to a mobile access gateway, proper tunneling techniques have to be in + place. Tunneling hides the network topology and allows the mobile + node's IPv6 datagram to be encapsulated as a payload of another IPv6 + packet and to be routed between the local mobility anchor and the + mobile access gateway. The Mobile IPv6 base specification [RFC3775] + defines the use of IPv6-over-IPv6 tunneling [RFC2473] between the + home agent and the mobile node, and this specification extends the + use of the same tunneling mechanism for use between the local + mobility anchor and the mobile access gateway. + + On most operating systems, a tunnel is implemented as a virtual + point-to-point interface. The source and the destination address of + the two endpoints of this virtual interface along with the + encapsulation mode are specified for this virtual interface. Any + packet that is routed over this interface gets encapsulated with the + outer header as specified for that point-to-point tunnel interface. + + For creating a point-to-point tunnel to any local mobility anchor, + the mobile access gateway may implement a tunnel interface with the + Source Address field set to a global address on its egress interface + (Proxy-CoA) and the destination address field set to the global + address of the local mobility anchor (LMAA). + + The following is the supported packet encapsulation mode that can be + used by the mobile access gateway and the local mobility anchor for + routing mobile node's IPv6 datagrams. + + o IPv6-In-IPv6 - IPv6 datagram encapsulated in an IPv6 packet + [RFC2473]. + + The companion document [IPV4-PMIP6] specifies other encapsulation + modes for supporting IPv4 transport. + + o IPv6-In-IPv4 - IPv6 datagram encapsulation in an IPv4 packet. The + details on how this mode is negotiated are specified in + [IPV4-PMIP6]. + + o IPv6-In-IPv4-UDP - IPv6 datagram encapsulation in an IPv4 UDP + packet. This mode is specified in [IPV4-PMIP6]. + + o IPv6-In-IPv4-UDP-TLV - IPv6 datagram encapsulation in an IPv4 UDP + packet with a TLV header. This mode is specified in [IPV4-PMIP6]. + + + + +Gundavelli, et al. Standards Track [Page 61] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +6.10.3. Local Routing + + If there is data traffic between a visiting mobile node and a + correspondent node that is locally attached to an access link + connected to the mobile access gateway, the mobile access gateway MAY + optimize on the delivery efforts by locally routing the packets and + by not reverse tunneling them to the mobile node's local mobility + anchor. The flag EnableMAGLocalRouting MAY be used for controlling + this behavior. However, in some systems, this may have an + implication on the mobile node's accounting and policy enforcement as + the local mobility anchor is not in the path for that traffic and it + will not be able to apply any traffic policies or do any accounting + for those flows. + + This decision of path optimization SHOULD be based on the policy + configured on the mobile access gateway, but enforced by the mobile + node's local mobility anchor. The specific details on how this is + achieved are beyond of the scope of this document. + +6.10.4. Tunnel Management + + All the considerations mentioned in Section 5.6.1 for the tunnel + management on the local mobility anchor apply for the mobile access + gateway as well. + +6.10.5. Forwarding Rules + + Forwarding Packets Sent to the Mobile Node's Home Network: + + o On receiving a packet from the bi-directional tunnel established + with the mobile node's local mobility anchor, the mobile access + gateway MUST use the destination address of the inner packet for + forwarding it on the interface where the destination network + prefix is hosted. The mobile access gateway MUST remove the outer + header before forwarding the packet. Considerations from + [RFC2473] MUST be applied for IPv6 decapsulation. If the mobile + access gateway cannot find the connected interface for that + destination address, it MUST silently drop the packet. For + reporting an error in such a scenario, in the form of an ICMP + control message, the considerations from [RFC2473] MUST be + applied. + + o On receiving a packet from a correspondent node that is connected + to the mobile access gateway as a regular IPv6 host (see Section + 6.14) destined to a mobile node that is also locally attached, the + mobile access gateway MUST check the flag EnableMAGLocalRouting to + determine if the packet can be delivered directly to the mobile + node. If the mobile access gateway is not allowed to route the + + + +Gundavelli, et al. Standards Track [Page 62] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + packet directly, it MUST route the packet towards the local + mobility anchor where the destination address is topologically + anchored, else it can route the packet directly to the mobile + node. + + Forwarding Packets Sent by the Mobile Node: + + o On receiving a packet from a mobile node connected to its access + link, the mobile access gateway MUST ensure that there is an + established binding for that mobile node with its local mobility + anchor before forwarding the packet directly to the destination or + before tunneling the packet to the mobile node's local mobility + anchor. + + o On receiving a packet from a mobile node connected to its access + link for a destination that is locally connected, the mobile + access gateway MUST check the flag EnableMAGLocalRouting, to + ensure the mobile access gateway is allowed to route the packet + directly to the destination. If the mobile access gateway is not + allowed to route the packet directly, it MUST route the packet + through the bi-directional tunnel established between itself and + the mobile node's local mobility anchor. Otherwise, it MUST route + the packet directly to the destination. + + o On receiving a packet from a mobile node connected to its access + link, to a destination that is not directly connected, the packet + MUST be forwarded to the local mobility anchor through the bi- + directional tunnel established between itself and the mobile + node's local mobility anchor. However, the packets that are sent + with the link-local source address MUST NOT be forwarded. + + o The format of the tunneled packet is shown below. Considerations + from [RFC2473] MUST be applied for IPv6 encapsulation. However, + when using IPv4 transport, the format of the tunneled packet is as + described in [IPV4-PMIP6]. + + IPv6 header (src= Proxy-CoA, dst= LMAA /* Tunnel Header */ + IPv6 header (src= MN-HoA, dst= CN ) /* Packet Header */ + Upper layer protocols /* Packet Content*/ + + Figure 14: Tunneled Packet from MAG to LMA + + o The format of the tunneled packet is shown below, when payload + protection using IPsec is enabled for the mobile node's data + traffic. However, when using IPv4 transport, the format of the + packet is as described in [IPV4-PMIP6]. + + + + + +Gundavelli, et al. Standards Track [Page 63] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + IPv6 header (src= Proxy-CoA, dst= LMAA /* Tunnel Header */ + ESP Header in tunnel mode /* ESP Header */ + IPv6 header (src= MN-HoA, dst= CN ) /* Packet Header */ + Upper layer protocols /* Packet Content*/ + + Figure 15: Tunneled Packet from MAG to LMA with Payload Protection + +6.11. Supporting DHCP-Based Address Configuration on the Access Link + + This section explains how Stateful Address Configuration using DHCP + support can be enabled in a Proxy Mobile IPv6 domain. It also + identifies the required configuration in DHCP and mobility + infrastructures for supporting this address configuration mode and + also identifies the protocol interactions between these two systems. + + o For supporting Stateful Address Configuration using DHCP, the DHCP + relay agent [RFC3315] service MUST be supported on all the mobile + access gateways in the Proxy Mobile IPv6 domain. Further, as + specified in Section 20 of [RFC3315], the DHCP relay agent should + be configured to use a list of destination addresses, which MAY + include unicast addresses, the All_DHCP_Servers multicast address, + or other addresses as required in a given deployment. + + o The DHCP infrastructure needs to be configured to assign addresses + from each of the prefixes assigned to a link in that Proxy Mobile + IPv6 domain. The DHCP relay agent indicates the link to which the + mobile node is attached by including an IPv6 address from any of + the prefixes assigned to that link in the link-address field of + the Relay Forward message. Therefore, for each link in the Mobile + IPv6 domain, the DHCP infrastructure will: + + * be configured with a list of all of the prefixes associated + with that link; + + * identify the link to which the mobile node is attached by + looking up the prefix for the link-address field in the Relay + Forward message in the list of prefixes associated with each + link; + + * assign to the host an address from each prefix associated with + the link to which the mobile node is attached. + + This DHCP infrastructure configuration requirement is identical to + other IPv6 networks; other than receiving DHCP messages from a + mobile node through different relay agents (MAGs) over time, the + DHCP infrastructure will be unaware of the mobile node's + capability with respect to mobility support. + + + + +Gundavelli, et al. Standards Track [Page 64] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + o The local mobility anchor needs to have the same awareness with + respect to the links along with the associated prefixes in a Proxy + Mobile IPv6 domain. When a local mobility anchor assigns + prefix(es) to a mobile node, it MUST assign all the prefixes + associated with a given link and all of those assigned prefixes + will remain as the home network prefixes for that mobile node + throughout the life of that mobility session. The serving mobile + access gateway that hosts these prefixes is physically connected + to that link and can function as the DHCP relay agent. This + common understanding between DHCP and mobility entities about all + the links in the domain along with the associated prefixes + provides the required coordination for allowing mobility entities + to perform prefix assignment dynamically to a mobile node and + still allow the DHCP infrastructure to perform address assignment + for that mobile node only from its home network prefixes. + + o When a mobile node sends a DHCP request message, the DHCP relay + agent function on the mobile access gateway will set the link- + address field in the DHCP message to an address in the mobile + node's home network prefix (any one of the mobile node's home + network prefixes assigned to that mobile node's attached + interface). The mobile access gateway can generate an + autoconfiguration address from one of the mobile node's home + network prefixes [RFC4862] and can use this address link-address + option, so as to provide a hint to the DHCP Server for the link + identification. The DHCP server, on receiving the request from + the mobile node, will allocate addresses from all the prefixes + associated with that link (identified using the link-address field + of the request). + + o Once the mobile node obtains address(es), moves to a different + link, and sends a DHCP request (at any time) for extending the + DHCP lease, the DHCP relay agent on the new link will set the + link-address field in the DHCP Relay Forward message to one of the + mobile node's home network prefixes. The DHCP server will + identify the client from the Client-DUID option and will identify + the link from the link-address option present in the request and + will allocate the same address(es) as before. + + o For correct operation of the model of network-based mobility + management in which the host does not participate in any mobility + management, the mobile node MUST always be assigned an identical + set of IPv6 addresses regardless of the access link to which the + mobile node is attached. For example, the mobile access gateways + + + + + + + +Gundavelli, et al. Standards Track [Page 65] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + in the Proxy Mobile IPv6 domain should be configured so that DHCP + messages from a mobile node will always be handled by the same + DHCP server or by a server from the same group of coordinated DHCP + servers serving that domain. DHCP-based address configuration is + not recommended for deployments in which the local mobility anchor + and the mobile access gateway are located in different + administrative domains. + +6.12. Home Network Prefix Renumbering + + If the mobile node's home network prefix(es) gets renumbered or + becomes invalid during the middle of a mobility session, the mobile + access gateway MUST withdraw the prefix(es) by sending a Router + Advertisement message on the access link with zero prefix lifetime + for the prefix(es) that is being renumbered. Also, the local + mobility anchor and the mobile access gateway MUST delete the created + routing state for the renumbered prefix(es). However, the specific + details on how the local mobility anchor notifies the mobile access + gateway about the mobile node's home network prefix(es) renumbering + are outside the scope of this document. + +6.13. Mobile Node Detachment Detection and Resource Cleanup + + Before sending a Proxy Binding Update message to the local mobility + anchor for extending the lifetime of a currently existing binding of + a mobile node, the mobile access gateway MUST make sure the mobile + node is still attached to the connected link by using some reliable + method. If the mobile access gateway cannot predictably detect the + presence of the mobile node on the connected link, it MUST NOT + attempt to extend the registration lifetime of the mobile node. + Further, in such a scenario, the mobile access gateway SHOULD + terminate the binding of the mobile node by sending a Proxy Binding + Update message to the mobile node's local mobility anchor with + lifetime value set to 0. It MUST also remove any local state such as + the Binding Update List entry created for that mobile node. + + The specific detection mechanism of the loss of a visiting mobile + node on the connected link is specific to the access link between the + mobile node and the mobile access gateway and is outside the scope of + this document. Typically, there are various link-layer-specific + events specific to each access technology that the mobile access + gateway can depend on for detecting the node loss. In general, the + mobile access gateway can depend on one or more of the following + methods for the detection presence of the mobile node on the + connected link: + + + + + + +Gundavelli, et al. Standards Track [Page 66] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + o Link-layer event specific to the access technology + + o Session termination event on point-to-point link types + + o IPv6 Neighbor Unreachability Detection event from IPv6 stack + + o Notification event from the local mobility anchor + +6.14. Allowing Network Access to Other IPv6 Nodes + + In some Proxy Mobile IPv6 deployments, network operators may + provision the mobile access gateway to offer network-based mobility + management service only to some visiting mobile nodes and enable just + regular IP access to some other nodes. This requires the network to + have control on when to enable network-based mobility management + service to a mobile node and when to enable regular IPv6 access. + This specification does not disallow such configuration. + + Upon detecting a mobile node on its access link and after policy + considerations, the mobile access gateway MUST determine if network- + based mobility management service should be offered to that mobile + node. If the mobile node is entitled to network-based mobility + management service, then the mobile access gateway must ensure the + mobile node does not detect any change with respect to its layer-3 + attachment, as explained in various sections of this specification. + + If the mobile node is not entitled to the network-based mobility + management service, as determined from the policy considerations, the + mobile access gateway MAY choose to offer regular IPv6 access to the + mobile node, and in such a scenario, the normal IPv6 considerations + apply. If IPv6 access is enabled, the mobile node SHOULD be able to + obtain IPv6 address(es) using the normal IPv6 address configuration + procedures. The obtained address(es) must be from a local visitor + network prefix(es). This essentially ensures that the mobile access + gateway functions as a normal access router to a mobile node attached + to its access link and without impacting its host-based mobility + protocol operation. + +7. Mobile Node Operation + + This non-normative section explains the mobile node's operation in a + Proxy Mobile IPv6 domain. + +7.1. Moving into a Proxy Mobile IPv6 Domain + + When a mobile node enters a Proxy Mobile IPv6 domain and attaches to + an access network, the mobile access gateway on the access link + detects the attachment of the mobile node and completes the binding + + + +Gundavelli, et al. Standards Track [Page 67] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + registration with the mobile node's local mobility anchor. If the + binding update operation is successfully performed, the mobile access + gateway will create the required state and set up the forwarding for + the mobile node's data traffic. + + When a mobile node attaches to the access link, it will typically + send a Router Solicitation message [RFC4861]. The mobile access + gateway on the access link will respond to the Router Solicitation + message with a Router Advertisement message. The Router + Advertisement message will carry the mobile node's home network + prefix(es), default-router address, and other address configuration + parameters. + + If the mobile access gateway on the access link receives a Router + Solicitation message from the mobile node, before it completes the + signaling with the mobile node's local mobility anchor, the mobile + access gateway may not know the mobile node's home network prefix(es) + and may not be able to emulate the mobile node's home link on the + access link. In such a scenario, the mobile node may notice a delay + before it receives a Router Advertisement message. This will also + affect mobile nodes that would be capable of handling their own + mobility, or mobile nodes that do not need to maintain the same IP + address through movements. + + If the received Router Advertisement message has the Managed Address + Configuration flag set, the mobile node, as it would normally do, + will send a DHCP Request [RFC3315]. The DHCP relay service enabled + on that access link will ensure the mobile node can obtain one or + more addresses from its home network prefix(es). + + If the received Router Advertisement message does not have the + Managed Address Configuration flag set and if the mobile node is + allowed to use autoconfigured address(es), the mobile node will be + able to obtain IPv6 address(es) from each of its home network + prefixes using any of the standard IPv6 address configuration + mechanisms permitted for that mode. + + If the mobile node is IPv4-enabled and if the network permits, it + will be able to obtain the IPv4 address configuration, as specified + in the companion document [IPV4-PMIP6]. + + Once the address configuration is complete, the mobile node can + continue to use this address configuration as long as it is attached + to the network that is in the scope of that Proxy Mobile IPv6 domain. + + + + + + + +Gundavelli, et al. Standards Track [Page 68] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +7.2. Roaming in the Proxy Mobile IPv6 Domain + + After obtaining the address configuration in the Proxy Mobile IPv6 + domain, as the mobile node moves and changes its point of attachment + from one mobile access gateway to the other, it can still continue to + use the same address configuration. As long as the attached access + link is in the scope of that Proxy Mobile IPv6 domain, the mobile + node will always detect the same router advertising itself as a + default-router and advertising the mobile node's home network + prefix(es) on each connected link. If the mobile node has address + configuration that it obtained using DHCP, it will be able to retain + the address configuration and extend the lease lifetime. + +8. Message Formats + + This section defines extensions to the Mobile IPv6 [RFC3775] protocol + messages. + +8.1. Proxy Binding Update Message + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Sequence # | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |A|H|L|K|M|R|P| Reserved | Lifetime | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + . . + . Mobility options . + . . + + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + A Binding Update message that is sent by a mobile access gateway to a + local mobility anchor is referred to as the "Proxy Binding Update" + message. A new flag (P) is included in the Binding Update message. + The rest of the Binding Update message format remains the same as + defined in [RFC3775] and with the additional (R) and (M) flags, as + specified in [RFC3963] and [RFC4140], respectively. + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 69] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + Proxy Registration Flag (P) + + A new flag (P) is included in the Binding Update message to + indicate to the local mobility anchor that the Binding Update + message is a proxy registration. The flag MUST be set to the + value of 1 for proxy registrations and MUST be set to 0 for direct + registrations sent by a mobile node. + + Mobility Options + + Variable-length field of such length that the complete Mobility + Header is an integer multiple of 8 octets long. This field + contains zero or more TLV-encoded mobility options. The encoding + and format of defined options are described in Section 6.2 of + [RFC3775]. The local mobility anchor MUST ignore and skip any + options that it does not understand. + + As per this specification, the following mobility options are + valid in a Proxy Binding Update message. These options can be + present in the message in any order. There can be one or more + instances of the Home Network Prefix options present in the + message. However, there cannot be more than one instance of any + of the following options. + + Mobile Node Identifier option + + Home Network Prefix option + + Handoff Indicator option + + Access Technology Type option + + Timestamp option + + Mobile Node Link-layer Identifier option + + Link-local Address option + + Additionally, there can be one or more instances of the Vendor- + Specific Mobility option [RFC5094]. + + For descriptions of other fields present in this message, refer to + Section 6.1.7 of [RFC3775]. + + + + + + + + +Gundavelli, et al. Standards Track [Page 70] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +8.2. Proxy Binding Acknowledgement Message + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Status |K|R|P|Reserved | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Sequence # | Lifetime | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + . . + . Mobility options . + . . + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + A Binding Acknowledgement message that is sent by a local mobility + anchor to a mobile access gateway is referred to as the "Proxy + Binding Acknowledgement" message. A new flag (P) is included in the + Binding Acknowledgement message. The rest of the Binding + Acknowledgement message format remains the same as defined in + [RFC3775] and with the additional (R) flag as specified in [RFC3963]. + + Proxy Registration Flag (P) + + A new flag (P) is included in the Binding Acknowledgement message + to indicate that the local mobility anchor that processed the + corresponding Proxy Binding Update message supports proxy + registrations. The flag is set to a value of 1 only if the + corresponding Proxy Binding Update had the Proxy Registration Flag + (P) set to value of 1. + + Mobility Options + + A variable-length field of such length that the complete Mobility + Header is an integer multiple of 8 octets long. This field + contains zero or more TLV-encoded mobility options. The encoding + and format of defined options are described in Section 6.2 of + [RFC3775]. The mobile access gateway MUST ignore and skip any + options that it does not understand. + + As per this specification, the following mobility options are + valid in a Proxy Binding Acknowledgement message. These options + can be present in the message in any order. There can be one or + + + + + + + +Gundavelli, et al. Standards Track [Page 71] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + more instances of the Home Network Prefix options present in the + message. However, there cannot be more than one instance of any + of the following options. + + Mobile Node Identifier option + + Home Network Prefix option + + Handoff Indicator option + + Access Technology Type option + + Timestamp option + + Mobile Node Link-layer Identifier option + + Link-local Address option + + Additionally, there can be one or more instances of the Vendor- + Specific Mobility option [RFC5094]. + + Status + + An 8-bit unsigned integer indicating the disposition of the Proxy + Binding Update. Values of the Status field less than 128 indicate + that the Proxy Binding Update was accepted by the local mobility + anchor. Values greater than or equal to 128 indicate that the + Proxy Binding Update message was rejected by the local mobility + anchor. Section 8.9 defines the Status values that can used in + Proxy Binding Acknowledgement message. + + For descriptions of other fields present in this message, refer to + Section 6.1.8 of [RFC3775]. + +8.3. Home Network Prefix Option + + A new option, Home Network Prefix option is defined for use with the + Proxy Binding Update and Proxy Binding Acknowledgement messages + exchanged between a local mobility anchor and a mobile access + gateway. This option is used for exchanging the mobile node's home + network prefix information. There can be multiple Home Network + Prefix options present in the message. + + The Home Network Prefix Option has an alignment requirement of 8n+4. + Its format is as follows: + + + + + + +Gundavelli, et al. Standards Track [Page 72] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | Reserved | Prefix Length | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + + + + | | + + Home Network Prefix + + | | + + + + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Type + 22 + + Length + + 8-bit unsigned integer indicating the length of the option + in octets, excluding the type and length fields. This field + MUST be set to 18. + + Reserved (R) + + This 8-bit field is unused for now. The value MUST be + initialized to 0 by the sender and MUST be ignored by the + receiver. + + Prefix Length + + 8-bit unsigned integer indicating the prefix length of the + IPv6 prefix contained in the option. + + Home Network Prefix + + A sixteen-byte field containing the mobile node's IPv6 Home + Network Prefix. + + +8.4. Handoff Indicator Option + + A new option, Handoff Indicator option is defined for use with the + Proxy Binding Update and Proxy Binding Acknowledgement messages + exchanged between a local mobility anchor and a mobile access + gateway. This option is used for exchanging the mobile node's + handoff-related hints. + + + + +Gundavelli, et al. Standards Track [Page 73] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + The Handoff Indicator option has no alignment requirement. Its + format is as follows: + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | Reserved (R) | HI | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Type + 23 + + Length + + 8-bit unsigned integer indicating the length of the option + in octets, excluding the type and length fields. This field + MUST be set to 2. + + Reserved (R) + + This 8-bit field is unused for now. The value MUST be + initialized to 0 by the sender and MUST be ignored by the + receiver. + + Handoff Indicator (HI) + + An 8-bit field that specifies the type of handoff. The values + (0 - 255) will be allocated and managed by IANA. The following + values are currently defined. + + 0: Reserved + 1: Attachment over a new interface + 2: Handoff between two different interfaces of the mobile node + 3: Handoff between mobile access gateways for the same interface + 4: Handoff state unknown + 5: Handoff state not changed (Re-registration) + + +8.5. Access Technology Type Option + + A new option, Access Technology Type option is defined for use with + the Proxy Binding Update and Proxy Binding Acknowledgement messages + exchanged between a local mobility anchor and a mobile access + gateway. This option is used for exchanging the type of the access + technology by which the mobile node is currently attached to the + mobile access gateway. + + + + + +Gundavelli, et al. Standards Track [Page 74] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + The Access Technology Type Option has no alignment requirement. Its + format is as follows: + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | Reserved (R) | ATT | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Type + 24 + + Length + + 8-bit unsigned integer indicating the length of the option + in octets, excluding the type and length fields. This field + MUST be set to 2. + + Reserved (R) + + This 8-bit field is unused for now. The value MUST be + initialized to 0 by the sender and MUST be ignored by the + receiver. + + Access Technology Type (ATT) + + An 8-bit field that specifies the access technology through + which the mobile node is connected to the access link on the + mobile access gateway. + + The values (0 - 255) will be allocated and managed by IANA. The + following values are currently reserved for the below specified + access technology types. + + 0: Reserved ("Reserved") + 1: Virtual ("Logical Network Interface") + 2: PPP ("Point-to-Point Protocol") + 3: IEEE 802.3 ("Ethernet") + 4: IEEE 802.11a/b/g ("Wireless LAN") + 5: IEEE 802.16e ("WIMAX") + + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 75] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +8.6. Mobile Node Link-layer Identifier Option + + A new option, Mobile Node Link-layer Identifier option is defined for + use with the Proxy Binding Update and Proxy Binding Acknowledgement + messages exchanged between a local mobility anchor and a mobile + access gateway. This option is used for exchanging the mobile node's + link-layer identifier. + + The format of the Link-layer Identifier option is shown below. Based + on the size of the identifier, the option MUST be aligned + appropriately, as per mobility option alignment requirements + specified in [RFC3775]. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | Reserved | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + + Link-layer Identifier + + . ... . + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Type + 25 + + Length + 8-bit unsigned integer indicating the length of the option + in octets, excluding the type and length fields. + + Reserved + + This field is unused for now. The value MUST be initialized to + 0 by the sender and MUST be ignored by the receiver. + + Link-layer Identifier + + A variable length field containing the mobile node's link-layer + identifier. + + The content and format of this field (including byte and bit + ordering) is as specified in Section 4.6 of [RFC4861] for + carrying link-layer addresses. On certain access links, where + the link-layer address is not used or cannot be determined, + this option cannot be used. + + + + + +Gundavelli, et al. Standards Track [Page 76] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +8.7. Link-local Address Option + + A new option, Link-local Address option is defined for use with the + Proxy Binding Update and Proxy Binding Acknowledgement messages + exchanged between a local mobility anchor and a mobile access + gateway. This option is used for exchanging the link-local address + of the mobile access gateway. + + The Link-local Address option has an alignment requirement of 8n+6. + Its format is as follows: + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + + + + | | + + Link-local Address + + | | + + + + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Type + 26 + + Length + + 8-bit unsigned integer indicating the length of the option + in octets, excluding the type and length fields. This field + MUST be set to 16. + + Link-local Address + + A sixteen-byte field containing the link-local address. + +8.8. Timestamp Option + + A new option, Timestamp option is defined for use in the Proxy + Binding Update and Proxy Binding Acknowledgement messages. + + The Timestamp option has an alignment requirement of 8n+2. Its + format is as follows: + + + + + + +Gundavelli, et al. Standards Track [Page 77] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + + Timestamp + + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Type + 27 + + Length + + 8-bit unsigned integer indicating the length in octets of + the option, excluding the type and length fields. The value + for this field MUST be set to 8. + + Timestamp + + A 64-bit unsigned integer field containing a timestamp. The + value indicates the number of seconds since January 1, 1970, + 00:00 UTC, by using a fixed point format. In this format, the + integer number of seconds is contained in the first 48 bits of + the field, and the remaining 16 bits indicate the number of + 1/65536 fractions of a second. + +8.9. Status Values + + This document defines the following new Status values for use in + Proxy Binding Acknowledgement messages. These values are to be + allocated from the same number space, as defined in Section 6.1.8 of + [RFC3775]. + + Status values less than 128 indicate that the Proxy Binding Update + message was accepted by the local mobility anchor. Status values + greater than 128 indicate that the Proxy Binding Update was rejected + by the local mobility anchor. + + PROXY_REG_NOT_ENABLED: 152 + + Proxy registration not enabled for the mobile node + + + + + + + + +Gundavelli, et al. Standards Track [Page 78] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + NOT_LMA_FOR_THIS_MOBILE_NODE: 153 + + Not local mobility anchor for this mobile node + + MAG_NOT_AUTHORIZED_FOR_PROXY_REG: 154 + + The mobile access gateway is not authorized to send proxy binding + updates + + NOT_AUTHORIZED_FOR_HOME_NETWORK_PREFIX: 155 + + The mobile node is not authorized for one or more of the + requesting home network prefixes + + TIMESTAMP_MISMATCH: 156 + + Invalid timestamp value (the clocks are out of sync) + + TIMESTAMP_LOWER_THAN_PREV_ACCEPTED: 157 + + The timestamp value is lower than the previously accepted value + + MISSING_HOME_NETWORK_PREFIX_OPTION: 158 + + Missing home network prefix option + + BCE_PBU_PREFIX_SET_DO_NOT_MATCH: 159 + + All the home network prefixes listed in the BCE do not match all + the prefixes in the received PBU + + MISSING_MN_IDENTIFIER_OPTION: 160 + + Missing mobile node identifier option + + MISSING_HANDOFF_INDICATOR_OPTION: 161 + + Missing handoff indicator option + + MISSING_ACCESS_TECH_TYPE_OPTION: 162 + + Missing access technology type option + + + + + + + + + +Gundavelli, et al. Standards Track [Page 79] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + Additionally, the following Status values defined in [RFC3775] can + also be used in a Proxy Binding Acknowledgement message. + + 0 Proxy Binding Update accepted + + 128 Reason unspecified + + 129 Administratively prohibited + + 130 Insufficient resources + +9. Protocol Configuration Variables + +9.1. Local Mobility Anchor - Configuration Variables + + The local mobility anchor MUST allow the following variables to be + configured by the system management. The configured values for these + protocol variables MUST survive server reboots and service restarts. + + MinDelayBeforeBCEDelete + + This variable specifies the amount of time in milliseconds the + local mobility anchor MUST wait before it deletes a Binding Cache + entry of a mobile node, upon receiving a Proxy Binding Update + message from a mobile access gateway with a lifetime value of 0. + During this wait time, if the local mobility anchor receives a + Proxy Binding Update for the same mobility binding, with a + lifetime value greater than 0, then it must update the binding + cache entry with the accepted binding values. By the end of this + wait-time, if the local mobility anchor did not receive any valid + Proxy Binding Update message for that mobility binding, it MUST + delete the Binding Cache entry. This delay essentially ensures a + mobile node's Binding Cache entry is not deleted too quickly and + allows some time for the new mobile access gateway to complete the + signaling for the mobile node. + + The default value for this variable is 10000 milliseconds. + + + + + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 80] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + MaxDelayBeforeNewBCEAssign + + This variable specifies the amount of time in milliseconds the + local mobility anchor MUST wait for the de-registration message + for an existing mobility session before it decides to create a new + mobility session. + + The default value for this variable is 1500 milliseconds. + + Note that there is a dependency between this value and the values + used in the retransmission algorithm for Proxy Binding Updates. + The retransmissions need to happen before + MaxDelayBeforeNewBCEAssign runs out, as otherwise there are + situations where a de-registration from a previous mobile access + gateway may be lost, and the local mobility anchor creates, + needlessly, a new mobility session and new prefixes for the mobile + node. However, this affects situations where there is no + information from the lower layers about the type of a handoff or + other parameters that can be used for identifying the mobility + session. + + TimestampValidityWindow + + This variable specifies the maximum amount of time difference in + milliseconds between the timestamp in the received Proxy Binding + Update message and the current time of day on the local mobility + anchor, that is allowed by the local mobility anchor for the + received message to be considered valid. + + The default value for this variable is 300 milliseconds. This + variable must be adjusted to suit the deployments. + +9.2. Mobile Access Gateway - Configuration Variables + + The mobile access gateway MUST allow the following variables to be + configured by the system management. The configured values for these + protocol variables MUST survive server reboots and service restarts. + + EnableMAGLocalRouting + + This flag indicates whether or not the mobile access gateway is + allowed to enable local routing of the traffic exchanged between a + visiting mobile node and a correspondent node that is locally + connected to one of the interfaces of the mobile access gateway. + The correspondent node can be another visiting mobile node as + well, or a local fixed node. + + + + + +Gundavelli, et al. Standards Track [Page 81] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + The default value for this flag is set to a value of 0, indicating + that the mobile access gateway MUST reverse tunnel all the traffic + to the mobile node's local mobility anchor. + + When the value of this flag is set to a value of 1, the mobile + access gateway MUST route the traffic locally. + + This aspect of local routing MAY be defined as policy on a per + mobile basis and when present will take precedence over this flag. + +9.3. Proxy Mobile IPv6 Domain - Configuration Variables + + All the mobile entities (local mobility anchors and mobile access + gateways) in a Proxy Mobile IPv6 domain MUST allow the following + variables to be configured by the system management. The configured + values for these protocol variables MUST survive server reboots and + service restarts. These variables MUST be globally fixed for a given + Proxy Mobile IPv6 domain resulting in the same values being enforced + on all the mobility entities in that domain. + + TimestampBasedApproachInUse + + This flag indicates whether or not the timestamp-based approach + for message ordering is in use in that Proxy Mobile IPv6 domain. + When the value for this flag is set to 1, all the mobile access + gateways in that Proxy Mobile IPv6 domain MUST apply the + timestamp-based considerations listed in Section 5.5. When the + value of this flag is set to 0, sequence-number-based + considerations listed in Section 5.5 MUST be applied. The default + value for this flag is set to value of 1, indicating that the + timestamp-based mechanism is in use in that Proxy Mobile IPv6 + domain. + + MobileNodeGeneratedTimestampInUse + + This flag indicates whether or not the mobile-node-generated + timestamp approach is in use in that Proxy Mobile IPv6 domain. + When the value for this flag is set to 1, the local mobility + anchors and mobile access gateways in that Proxy Mobile IPv6 + domain MUST apply the mobile node generated timestamp + considerations as specified in Section 5.5. + + This flag is relevant only when timestamp-based approach is in + use. The value for this flag MUST NOT be set to value of 1, if + the value of the TimestampBasedApproachInUse flag is set to 0. + + + + + + +Gundavelli, et al. Standards Track [Page 82] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + The default value for this flag is set to value of 0, indicating + that the mobile node generated timestamp mechanism is not in use + in that Proxy Mobile IPv6 domain. + + FixedMAGLinkLocalAddressOnAllAccessLinks + + This variable indicates the link-local address value that all the + mobile access gateways SHOULD use on any of the access links + shared with any of the mobile nodes in that Proxy Mobile IPv6 + domain. If this variable is initialized to ALL_ZERO value, it + implies the use of fixed link-local address mode is not enabled + for that Proxy Mobile IPv6 domain. + + FixedMAGLinkLayerAddressOnAllAccessLinks + + This variable indicates the link-layer address value that all the + mobile access gateways SHOULD use on any of the access links + shared with any of the mobile nodes in that Proxy Mobile IPv6 + domain. For access technologies where there is no link-layer + address, this variable MUST be initialized to ALL_ZERO value. + +10. IANA Considerations + + This document defines six new Mobility Header options, the Home + Network Prefix Option, Handoff Indicator Option, Access Technology + Type Option, Mobile Node Link-layer Identifier Option, Link-local + Address Option, and Timestamp Option. These options are described in + Section 8. The Type value for these options has been assigned from + the same numbering space as allocated for the other mobility options, + as defined in [RFC3775]. + + The Handoff Indicator Option, defined in Section 8.4 of this + document, introduces a new Handoff Indicator (HI) numbering space, + where the values from 0 to 5 have been reserved by this document. + Approval of new Handoff Indicator type values are to be made through + IANA Expert Review. + + The Access Technology Type Option, defined in Section 8.5 of this + document, introduces a new Access Technology type (ATT) numbering + space, where the values from 0 to 5 have been reserved by this + document. Approval of new Access Technology type values are to be + made through IANA Expert Review. + + This document also defines new Binding Acknowledgement status values, + as described in Section 8.9. The status values MUST be assigned from + the same number space used for Binding Acknowledgement status values, + as defined in [RFC3775]. The allocated values for each of these + status values must be greater than 128. + + + +Gundavelli, et al. Standards Track [Page 83] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + This document creates a new registry for the flags in the Binding + Update message called the "Binding Update Flags". + + The following flags are reserved: + + (A) 0x8000 [RFC3775] + + (H) 0x4000 [RFC3775] + + (L) 0x2000 [RFC3775] + + (K) 0x1000 [RFC3775] + + (M) 0x0800 [RFC4140] + + (R) 0x0400 [RFC3963] + + This document reserves a new flag (P) as follows: + + (P) 0x0200 + + The rest of the values in the 16-bit field are reserved. New values + can be assigned by Standards Action or IESG approval. + + This document also creates a new registry for the flags in the + Binding Acknowledgment message called the "Binding Acknowledgment + Flags". The following values are reserved. + + (K) 0x80 [RFC3775] + + (R) 0x40 [RFC3963] + + This document reserves a new flag (P) as follows: + + (P) 0x20 + + The rest of the values in the 8-bit field are reserved. New values + can be assigned by Standards Action or IESG approval. + +11. Security Considerations + + The potential security threats against any network-based mobility + management protocol are described in [RFC4832]. This section + explains how Proxy Mobile IPv6 protocol defends itself against those + threats. + + + + + + +Gundavelli, et al. Standards Track [Page 84] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + Proxy Mobile IPv6 protocol recommends the signaling messages, Proxy + Binding Update and Proxy Binding Acknowledgement, exchanged between + the mobile access gateway and the local mobility anchor to be + protected using IPsec using the established security association + between them. This essentially eliminates the threats related to the + impersonation of the mobile access gateway or the local mobility + anchor. + + This specification allows a mobile access gateway to send binding + registration messages on behalf of a mobile node. If proper + authorization checks are not in place, a malicious node may be able + to hijack a mobile node's mobility session or may carry out a denial- + of-service attack. To prevent this attack, this specification + requires the local mobility anchor to allow only authorized mobile + access gateways that are part of that Proxy Mobile IPv6 domain to + send Proxy Binding Update messages on behalf of a mobile node. + + To eliminate the threats on the interface between the mobile access + gateway and the mobile node, this specification requires an + established trust between the mobile access gateway and the mobile + node and to authenticate and authorize the mobile node before it is + allowed to access the network. Further, the established + authentication mechanisms enabled on that access link will ensure + that there is a secure binding between the mobile node's identity and + its link-layer address. The mobile access gateway will definitively + identify the mobile node from the packets that it receives on that + access link. + + To address the threat related to a compromised mobile access gateway, + the local mobility anchor, before accepting a Proxy Binding Update + message for a given mobile node, may ensure that the mobile node is + attached to the mobile access gateway that sent the Proxy Binding + Update message. This may be accomplished by contacting a trusted + entity, which is able to track the mobile node's current point of + attachment. However, the specific details of the actual mechanisms + for achieving this is outside the scope of this document. + +12. Acknowledgements + + The authors would like to specially thank Jari Arkko, Julien + Laganier, Christian Vogt, Dave Thaler, Pasi Eronen, Pete McCann, + Brian Haley, Ahmad Muhanna, JinHyeock Choi, and Elwyn Davies for + their thorough reviews of this document. + + The authors would also like to thank Alex Petrescu, Alice Qinxia, + Alper Yegin, Ashutosh Dutta, Behcet Sarikaya, Charles Perkins, + Domagoj Premec, Fred Templin, Genadi Velev, George Tsirtsis, Gerardo + Giaretta, Henrik Levkowetz, Hesham Soliman, James Kempf, Jean-Michel + + + +Gundavelli, et al. Standards Track [Page 85] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + Combes, John Jason Brzozowski, Jun Awano, John Zhao, Jong-Hyouk Lee, + Jonne Soininen, Jouni Korhonen, Kalin Getov, Kilian Weniger, Lars + Eggert, Magnus Westerlund, Marco Liebsch, Mohamed Khalil, Nishida + Katsutoshi, Pierrick Seite, Phil Roberts, Ralph Droms, Ryuji + Wakikawa, Sangjin Jeong, Suresh Krishnan, Tero Kauppinen, Uri + Blumenthal, Ved Kafle, Vidya Narayanan, Youn-Hee Han, and many others + for their passionate discussions in the working group mailing list on + the topic of localized mobility management solutions. These + discussions stimulated much of the thinking and shaped the document + to the current form and we acknowledge that! + + The authors would also like to thank Ole Troan, Akiko Hattori, Parviz + Yegani, Mark Grayson, Michael Hammer, Vojislav Vucetic, Jay Iyer, Tim + Stammers, Bernie Volz, and Josh Littlefield for their input on this + document. + +13. References + +13.1. Normative References + + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. + + [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in + IPv6 Specification", RFC 2473, December 1998. + + [RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The + Addition of Explicit Congestion Notification (ECN) to + IP", RFC 3168, September 2001. + + [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., + and M. Carney, "Dynamic Host Configuration Protocol for + IPv6 (DHCPv6)", RFC 3315, July 2003. + + [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility + Support in IPv6", RFC 3775, June 2004. + + [RFC4282] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The + Network Access Identifier", RFC 4282, December 2005. + + [RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K. + Chowdhury, "Mobile Node Identifier Option for Mobile + IPv6 (MIPv6)", RFC 4283, November 2005. + + [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing + Architecture", RFC 4291, February 2006. + + + + + +Gundavelli, et al. Standards Track [Page 86] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + [RFC4301] Kent, S. and K. Seo, "Security Architecture for the + Internet Protocol", RFC 4301, December 2005. + + [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", + RFC 4303, December 2005. + + [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, + "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, + September 2007. + +13.2. Informative References + + [RFC1981] McCann, J., Deering, S., and J. Mogul, "Path MTU + Discovery for IP version 6", RFC 1981, August 1996. + + [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, + "Remote Authentication Dial In User Service (RADIUS)", + RFC 2865, June 2000. + + [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and + J. Arkko, "Diameter Base Protocol", RFC 3588, + September 2003. + + [RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P. + Thubert, "Network Mobility (NEMO) Basic Support + Protocol", RFC 3963, January 2005. + + [RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, + "SEcure Neighbor Discovery (SEND)", RFC 3971, + March 2005. + + [RFC4140] Soliman, H., Castelluccia, C., El Malki, K., and L. + Bellier, "Hierarchical Mobile IPv6 Mobility Management + (HMIPv6)", RFC 4140, August 2005. + + [RFC4306] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", + RFC 4306, December 2005. + + [RFC4330] Mills, D., "Simple Network Time Protocol (SNTP) Version + 4 for IPv4, IPv6 and OSI", RFC 4330, January 2006. + + [RFC4372] Adrangi, F., Lior, A., Korhonen, J., and J. Loughney, + "Chargeable User Identity", RFC 4372, January 2006. + + [RFC4821] Mathis, M. and J. Heffner, "Packetization Layer Path + MTU Discovery", RFC 4821, March 2007. + + + + + +Gundavelli, et al. Standards Track [Page 87] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + [RFC4830] Kempf, J., "Problem Statement for Network-Based + Localized Mobility Management (NETLMM)", RFC 4830, + April 2007. + + [RFC4831] Kempf, J., "Goals for Network-Based Localized Mobility + Management (NETLMM)", RFC 4831, April 2007. + + [RFC4832] Vogt, C. and J. Kempf, "Security Threats to Network- + Based Localized Mobility Management (NETLMM)", + RFC 4832, April 2007. + + [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless + Address Autoconfiguration", RFC 4862, September 2007. + + [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy + Extensions for Stateless Address Autoconfiguration in + IPv6", RFC 4941, September 2007. + + [RFC5094] Devarapalli, V., Patel, A., and K. Leung, "Mobile IPv6 + Vendor Specific Option", RFC 5094, December 2007. + + [IPV4-PMIP6] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy + Mobile IPv6", Work in Progress, May 2008. + + [DNAV6] Narayanan, S., Ed., "Detecting Network Attachment in + IPv6 Networks (DNAv6)", Work in Progress, + February 2008. + + + + + + + + + + + + + + + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 88] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +Appendix A. Proxy Mobile IPv6 Interactions with AAA Infrastructure + + Every mobile node that roams in a proxy Mobile IPv6 domain would + typically be identified by an identifier, MN-Identifier, and that + identifier will have an associated policy profile that identifies the + mobile node's home network prefix(es) on a per-interface basis, + permitted address configuration modes, roaming policy, and other + parameters that are essential for providing network-based mobility + management service. This information is typically configured in AAA. + In some cases, the home network prefix(es) may be dynamically + assigned to the mobile node's interface, after its initial attachment + to the Proxy Mobile IPv6 domain over that interface and may not be + configured in the mobile node's policy profile. + + The network entities in the proxy Mobile IPv6 domain, while serving a + mobile node, will have access to the mobile node's policy profile and + these entities can query this information using RADIUS [RFC2865] or + DIAMETER [RFC3588] protocols. + +Appendix B. Routing State + + The following section explains the routing state created for a mobile + node on the mobile access gateway. This routing state reflects only + one specific way of implementation, and one MAY choose to implement + it in other ways. The policy based route defined below acts as a + traffic selection rule for routing a mobile node's traffic through a + specific tunnel created between the mobile access gateway and that + mobile node's local mobility anchor and with the specific + encapsulation mode, as negotiated. + + The below example identifies the routing state for two visiting + mobile nodes, MN1 and MN2, with their respective local mobility + anchors, LMA1 and LMA2. + + For all traffic from the mobile node, identified by the mobile node's + MAC address, ingress interface or source prefix (MN-HNP) to + _ANY_DESTINATION_ route via interface tunnel0, next-hop LMAA. + + + + + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 89] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + + +==================================================================+ + | Packet Source | Destination Address | Destination Interface | + +==================================================================+ + | MAC_Address_MN1, | _ANY_DESTINATION_ | Tunnel0 | + | (IPv6 Prefix or |----------------------------------------------| + | Input Interface) | Locally Connected | Tunnel0 | + +------------------------------------------------------------------+ + | MAC_Address_MN2, | _ANY_DESTINATION_ | Tunnel1 | + + (IPv6 Prefix or -----------------------------------------------| + | Input Interface | Locally Connected | direct | + +------------------------------------------------------------------+ + + Example - Policy-Based Route Table + + + +==================================================================+ + | Interface | Source Address | Destination Address | Encapsulation | + +==================================================================+ + | Tunnel0 | Proxy-CoA | LMAA1 | IPv6-in-IPv6 | + +------------------------------------------------------------------+ + | Tunnel1 | Proxy-CoA | LMAA2 | IPv6-in-IPv6 | + +------------------------------------------------------------------+ + + Example - Tunnel Interface Table + + + + + + + + + + + + + + + + + + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 90] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +Authors' Addresses + + Sri Gundavelli (editor) + Cisco + 170 West Tasman Drive + San Jose, CA 95134 + USA + + EMail: sgundave@cisco.com + + + Kent Leung + Cisco + 170 West Tasman Drive + San Jose, CA 95134 + USA + + EMail: kleung@cisco.com + + + Vijay Devarapalli + Wichorus + 3590 North First Street + San Jose, CA 95134 + USA + + EMail: vijay@wichorus.com + + + Kuntal Chowdhury + Starent Networks + 30 International Place + Tewksbury, MA + + EMail: kchowdhury@starentnetworks.com + + + Basavaraj Patil + Nokia + 6000 Connection Drive + Irving, TX 75039 + USA + + EMail: basavaraj.patil@nokia.com + + + + + + + +Gundavelli, et al. Standards Track [Page 91] + +RFC 5213 Proxy Mobile IPv6 August 2008 + + +Full Copyright Statement + + Copyright (C) The IETF Trust (2008). + + This document is subject to the rights, licenses and restrictions + contained in BCP 78, and except as set forth therein, the authors + retain all their rights. + + This document and the information contained herein are provided on an + "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS + OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND + THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS + OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF + THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED + WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. + +Intellectual Property + + The IETF takes no position regarding the validity or scope of any + Intellectual Property Rights or other rights that might be claimed to + pertain to the implementation or use of the technology described in + this document or the extent to which any license under such rights + might or might not be available; nor does it represent that it has + made any independent effort to identify any such rights. Information + on the procedures with respect to rights in RFC documents can be + found in BCP 78 and BCP 79. + + Copies of IPR disclosures made to the IETF Secretariat and any + assurances of licenses to be made available, or the result of an + attempt made to obtain a general license or permission for the use of + such proprietary rights by implementers or users of this + specification can be obtained from the IETF on-line IPR repository at + http://www.ietf.org/ipr. + + The IETF invites any interested party to bring to its attention any + copyrights, patents or patent applications, or other proprietary + rights that may cover technology that may be required to implement + this standard. Please address the information to the IETF at + ietf-ipr@ietf.org. + + + + + + + + + + + + +Gundavelli, et al. Standards Track [Page 92] + |