diff options
Diffstat (limited to 'doc/rfc/rfc9127.txt')
| -rw-r--r-- | doc/rfc/rfc9127.txt | 3289 |
1 files changed, 3289 insertions, 0 deletions
diff --git a/doc/rfc/rfc9127.txt b/doc/rfc/rfc9127.txt new file mode 100644 index 0000000..3bf4dac --- /dev/null +++ b/doc/rfc/rfc9127.txt @@ -0,0 +1,3289 @@ + + + + +Internet Engineering Task Force (IETF) R. Rahman, Ed. +Request for Comments: 9127 +Category: Standards Track L. Zheng, Ed. +ISSN: 2070-1721 Huawei Technologies + M. Jethanandani, Ed. + Xoriant Corporation + S. Pallagatti + VMware + G. Mirsky + Ericsson + October 2021 + + + YANG Data Model for Bidirectional Forwarding Detection (BFD) + +Abstract + + This document defines a YANG data model that can be used to configure + and manage Bidirectional Forwarding Detection (BFD). + + The YANG modules in this document conform to the Network Management + Datastore Architecture (NMDA) (RFC 8342). + +Status of This Memo + + This is an Internet Standards Track document. + + This document is a product of the Internet Engineering Task Force + (IETF). It represents the consensus of the IETF community. It has + received public review and has been approved for publication by the + Internet Engineering Steering Group (IESG). Further information on + Internet Standards is available in Section 2 of RFC 7841. + + Information about the current status of this document, any errata, + and how to provide feedback on it may be obtained at + https://www.rfc-editor.org/info/rfc9127. + +Copyright Notice + + Copyright (c) 2021 IETF Trust and the persons identified as the + document authors. All rights reserved. + + This document is subject to BCP 78 and the IETF Trust's Legal + Provisions Relating to IETF Documents + (https://trustee.ietf.org/license-info) in effect on the date of + publication of this document. Please review these documents + carefully, as they describe your rights and restrictions with respect + to this document. Code Components extracted from this document must + include Simplified BSD License text as described in Section 4.e of + the Trust Legal Provisions and are provided without warranty as + described in the Simplified BSD License. + +Table of Contents + + 1. Introduction + 1.1. Tree Diagrams + 2. Design of the Data Model + 2.1. Design of the Configuration Model + 2.1.1. Common BFD Configuration Parameters + 2.1.2. Single-Hop IP + 2.1.3. Multihop IP + 2.1.4. MPLS Label Switched Paths + 2.1.5. Link Aggregation Groups + 2.2. Design of the Operational State Model + 2.3. Notifications + 2.4. RPC Operations + 2.5. BFD Top-Level Hierarchy + 2.6. BFD IP Single-Hop Hierarchy + 2.7. BFD IP Multihop Hierarchy + 2.8. BFD-over-LAG Hierarchy + 2.9. BFD-over-MPLS-LSPs Hierarchy + 2.10. Interaction with Other YANG Modules + 2.10.1. "ietf-interfaces" Module + 2.10.2. "ietf-ip" Module + 2.10.3. "ietf-mpls" Module + 2.11. IANA BFD YANG Module + 2.12. BFD Types YANG Module + 2.13. BFD Top-Level YANG Module + 2.14. BFD IP Single-Hop YANG Module + 2.15. BFD IP Multihop YANG Module + 2.16. BFD-over-LAG YANG Module + 2.17. BFD-over-MPLS YANG Module + 3. Data Model Examples + 3.1. IP Single-Hop + 3.2. IP Multihop + 3.3. LAG + 3.4. MPLS + 4. Security Considerations + 5. IANA Considerations + 5.1. IANA-Maintained "iana-bfd-types" Module + 6. References + 6.1. Normative References + 6.2. Informative References + Appendix A. Echo Function Configuration Example + A.1. Example YANG Module for BFD Echo Function Configuration + Acknowledgments + Authors' Addresses + +1. Introduction + + This document defines a YANG data model that can be used to configure + and manage Bidirectional Forwarding Detection (BFD) [RFC5880]. BFD + is a network protocol that is used for liveness detection of + arbitrary paths between systems. Some examples of different types of + paths over which we have BFD are as follows: + + 1. Two systems directly connected via IP. This is known as BFD over + single-hop IP, a.k.a. BFD for IPv4 and IPv6 [RFC5881]. + + 2. Two systems connected via multiple hops as described in + "Bidirectional Forwarding Detection (BFD) for Multihop Paths" + [RFC5883]. + + 3. Two systems connected via MPLS Label Switched Paths (LSPs) as + described in "Bidirectional Forwarding Detection (BFD) for MPLS + Label Switched Paths (LSPs)" [RFC5884]. + + 4. Two systems connected via a Link Aggregation Group (LAG) + interface as described in "Bidirectional Forwarding Detection + (BFD) on Link Aggregation Group (LAG) Interfaces" [RFC7130]. + + 5. Two systems connected via pseudowires (PWs). This is known as + Virtual Circuit Connectivity Verification (VCCV), as described in + "Bidirectional Forwarding Detection (BFD) for the Pseudowire + Virtual Circuit Connectivity Verification (VCCV)" [RFC5885]. + This scenario is not addressed in this document. + + BFD typically does not operate on its own. Various control + protocols, also known as BFD clients, use the services provided by + BFD for their own operation, as described in "Generic Application of + Bidirectional Forwarding Detection (BFD)" [RFC5882]. The obvious + candidates that use BFD are those that do not have "hellos" to detect + failures, e.g., static routes, and routing protocols whose "hellos" + do not support sub-second failure detection, e.g., OSPF and IS-IS. + + The YANG modules in this document conform to the Network Management + Datastore Architecture (NMDA) [RFC8342]. This means that the data + models do not have separate top-level or sibling containers for + configuration data and operational state data. + +1.1. Tree Diagrams + + This document uses the graphical representation of data models, as + defined in [RFC8340]. + +2. Design of the Data Model + + Since BFD is used for liveness detection of various forwarding paths, + there is no uniform key to identify a BFD session, and so the BFD + data model is split into multiple YANG modules where each module + corresponds to one type of forwarding path. For example, BFD for IP + single-hop is in one YANG module, and BFD for MPLS is in another YANG + module. The main difference between these modules is how a BFD + session is uniquely identified, i.e., the key for the list containing + the BFD sessions for that forwarding path. To avoid duplication of + BFD definitions, we have common types and groupings that are used by + all the modules. + + A new control-plane protocol, "bfdv1", is defined, and a "bfd" + container is created under "control-plane-protocol" as specified in + "A YANG Data Model for Routing Management (NMDA Version)" [RFC8349]. + This new "bfd" container is augmented by the following YANG modules + for their respective specific information: + + 1. The "ietf-bfd-ip-sh" module (Section 2.14) augments "/routing/ + control-plane-protocols/control-plane-protocol/bfd/" with the + "ip-sh" container for BFD sessions over IP single-hop. + + 2. The "ietf-bfd-ip-mh" module (Section 2.15) augments "/routing/ + control-plane-protocols/control-plane-protocol/bfd/" with the + "ip-mh" container for BFD sessions over IP multihop. + + 3. The "ietf-bfd-lag" module (Section 2.16) augments "/routing/ + control-plane-protocols/control-plane-protocol/bfd/" with the + "lag" container for BFD sessions over a LAG. + + 4. The "ietf-bfd-mpls" module (Section 2.17) augments "/routing/ + control-plane-protocols/control-plane-protocol/bfd/" with the + "mpls" container for BFD-over-MPLS LSPs. + + BFD can operate in the following contexts: + + 1. At the network device level. + + 2. In logical network elements (LNEs) as described in "YANG Model + for Logical Network Elements" [RFC8530]. + + 3. In network instances as described in "YANG Data Model for Network + Instances" [RFC8529]. + + When used at the network device level, the BFD YANG data model is + used "as is". When the BFD YANG data model is used in an LNE or + network instance, the BFD YANG data model augments the mounted + routing model for the LNE or network instance. + +2.1. Design of the Configuration Model + + The configuration model consists mainly of the parameters specified + in BFD [RFC5880] -- for example, desired minimum transmit interval, + required minimum receive interval, and detection multiplier. + + BFD clients are applications that use BFD for fast detection of + failures. Some implementations have BFD session configuration under + the BFD clients -- for example, BFD session configuration under + routing applications such as OSPF, IS-IS, or BGP. Other + implementations have BFD session configuration centralized under BFD, + i.e., outside the multiple BFD clients. + + The main BFD parameters of interest to a BFD client are those related + to the multiplier and interval(s), since those parameters impact the + convergence time of the BFD clients when a failure occurs. Other + parameters, such as BFD authentication, are not specific to the + requirements of the BFD client. Configuration of BFD for all clients + should be centralized. However, this is a problem for BFD clients + that auto-discover their peers. For example, IGPs do not have the + peer address configured; instead, the IGP is enabled on an interface, + and the IGP peers are auto-discovered. So, for an operator to + configure BFD to an IGP peer, the operator would first have to + determine the peer addresses. And when a new peer is discovered, BFD + configuration would need to be added. To avoid this issue, we define + the grouping "client-cfg-parms" in Section 2.12 for BFD clients to + configure BFD: this allows BFD clients, such as the IGPs, to have + configuration (multiplier and intervals) for the BFD sessions they + need. For example, when a new IGP peer is discovered, the IGP would + create a BFD session to the newly discovered peer; similarly, when an + IGP peer goes away, the IGP would remove the BFD session to that + peer. The mechanism for how the BFD sessions are created and removed + by the BFD clients is outside the scope of this document, but this + would typically be done by using an API implemented by the BFD module + on the system. In the case of BFD clients that create BFD sessions + via their own configuration, authentication parameters (if required) + are still specified in BFD. + +2.1.1. Common BFD Configuration Parameters + + The basic BFD configuration parameters are as follows: + + local-multiplier + This is the detection time multiplier as defined in BFD [RFC5880]. + + desired-min-tx-interval + This is the Desired Min TX Interval as defined in BFD [RFC5880]. + + required-min-rx-interval + This is the Required Min RX Interval as defined in BFD [RFC5880]. + + Although BFD [RFC5880] allows for different values for transmit and + receive intervals, some implementations allow users to specify just + one interval that is used for both transmit and receive intervals, or + separate values for transmit and receive intervals. The BFD YANG + data model supports this: there is a choice between "min-interval", + used for both transmit and receive intervals, and "desired-min-tx- + interval" and "required-min-rx-interval". This is supported via the + "base-cfg-parms" grouping (Section 2.12), which is used by the YANG + modules for the various forwarding paths. + + For BFD authentication, we have the following: + + key-chain + This is a reference to "key-chain" as defined in "YANG Data Model + for Key Chains" [RFC8177]. The keys, cryptographic algorithms, + key lifetime, etc. are all defined in the "key-chain" model. + + meticulous + This enables a meticulous mode as per BFD [RFC5880]. + +2.1.2. Single-Hop IP + + For single-hop IP, there is an augment of the "bfd" data node, as + described in Section 2. The "ip-sh" node contains a list of IP + single-hop sessions where each session is uniquely identified by the + interface and destination address pair. We use the configuration + parameters defined in Section 2.1.1. The "ip-sh" node also contains + a list of interfaces and is used to specify authentication parameters + for BFD sessions that are created by BFD clients. See Section 2.1. + + [RFC5880] and [RFC5881] do not specify whether the Echo function + operates continuously or on demand. Therefore, the mechanism used to + start and stop the Echo function is implementation specific and + should be done by augmentation: + + 1. Configuration. This is suitable for an Echo function that + operates continuously. An example is provided in Appendix A. + + 2. RPC. This is suitable for an Echo function that operates on + demand. + +2.1.3. Multihop IP + + For multihop IP, there is an augment of the "bfd" data node, as + described in Section 2. + + Because of multiple paths, there could be multiple multihop IP + sessions between a source and a destination address. We identify + this set of sessions as a "session-group". The key for each + "session-group" consists of the following: + + Source address + Address belonging to the local system as per "Bidirectional + Forwarding Detection (BFD) for Multihop Paths" [RFC5883]. + + Destination address + Address belonging to the remote system as per [RFC5883]. + + We use the configuration parameters defined in Section 2.1.1. + + This document also provides the following parameters: + + tx-ttl + TTL of outgoing BFD control packets. + + rx-ttl + Minimum TTL of incoming BFD control packets. + +2.1.4. MPLS Label Switched Paths + + Here, we address MPLS LSPs whose Forwarding Equivalence Class (FEC) + [RFC3031] is an IP address. The "bfd" node (Section 2) is augmented + with "mpls", which contains a list of sessions uniquely identified by + an IP prefix. Because of multiple paths, there could be multiple + MPLS sessions to an MPLS FEC. We identify this set of sessions as a + "session-group". + + Since these LSPs are unidirectional, there is no LSP configuration on + the egress node. + + The BFD parameters for the egress node are added under "mpls". + +2.1.5. Link Aggregation Groups + + Per "Bidirectional Forwarding Detection (BFD) on Link Aggregation + Group (LAG) Interfaces" [RFC7130], configuring BFD on a LAG consists + of having micro-BFD sessions on each LAG member link. Since the BFD + parameters are an attribute of the LAG, they should be under the LAG. + However, there is no LAG YANG data model that we can augment. So, a + "lag" data node is added to the "bfd" node; see Section 2. The + configuration is per LAG: we have a list of LAGs. The destination IP + address of the micro-BFD sessions is configured per LAG and per + address family (IPv4 and IPv6). + +2.2. Design of the Operational State Model + + The operational state model contains both the overall statistics for + the BFD sessions running on the device and the per-session + operational information. + + The overall statistics for the BFD sessions consist of the number of + BFD sessions, the number of BFD sessions that are up, etc. This + information is available globally (i.e., for all BFD sessions) under + the "bfd" node (Section 2) and also per type of forwarding path. + + For each BFD session, three main categories of operational state data + are shown. + + 1. The first category includes fundamental information regarding a + BFD session, such as the local discriminator, the remote + discriminator, and the ability to support Demand mode. + + 2. The second category includes BFD "session-running" information, + e.g., the remote BFD state and the diagnostic code received. + Another example is the actual transmit interval between the + control packets, which may be different from the configured + desired minimum transmit interval. Similar examples include the + actual receive interval between the control packets and the + actual transmit interval between the Echo packets. + + 3. The third category contains the detailed statistics for the + session, e.g., when the session transitioned up/down and how long + it has been in that state. + + For some path types, there may be more than one session on the + virtual path to the destination. For example, with IP multihop and + MPLS LSPs, there could be multiple BFD sessions from the source to + the same destination to test the various paths (ECMP) to the + destination. This is represented by having multiple "sessions" under + each "session-group". + +2.3. Notifications + + This YANG data model defines notifications to inform end users of + important events detected during the protocol operation. The local + discriminator identifies the corresponding BFD session on the local + system, and the remote discriminator identifies the BFD session on + the remote system. Notifications also give more important details + about BFD sessions, e.g., new state, time in previous state, network + instance, and the reason that the BFD session state changed. The + notifications are defined for each type of forwarding path but use + groupings for common information. + +2.4. RPC Operations + + None. + +2.5. BFD Top-Level Hierarchy + + At the "bfd" node under "control-plane-protocol", there is no + configuration data -- only operational state data. The operational + state data consists of overall BFD session statistics, i.e., for BFD + on all types of forwarding paths. + + module: ietf-bfd + augment /rt:routing/rt:control-plane-protocols + /rt:control-plane-protocol: + +--rw bfd + +--ro summary + +--ro number-of-sessions? yang:gauge32 + +--ro number-of-sessions-up? yang:gauge32 + +--ro number-of-sessions-down? yang:gauge32 + +--ro number-of-sessions-admin-down? yang:gauge32 + +2.6. BFD IP Single-Hop Hierarchy + + An "ip-sh" node is added under the "bfd" node in "control-plane- + protocol". The configuration data and operational state data for + each BFD IP single-hop session are under this "ip-sh" node. + + module: ietf-bfd-ip-sh + augment /rt:routing/rt:control-plane-protocols + /rt:control-plane-protocol/bfd:bfd: + +--rw ip-sh + +--ro summary + | +--ro number-of-sessions? yang:gauge32 + | +--ro number-of-sessions-up? yang:gauge32 + | +--ro number-of-sessions-down? yang:gauge32 + | +--ro number-of-sessions-admin-down? yang:gauge32 + +--rw sessions + | +--rw session* [interface dest-addr] + | +--rw interface if:interface-ref + | +--rw dest-addr inet:ip-address + | +--rw source-addr? inet:ip-address + | +--rw local-multiplier? multiplier + | +--rw (interval-config-type)? + | | +--:(tx-rx-intervals) + | | | +--rw desired-min-tx-interval? uint32 + | | | +--rw required-min-rx-interval? uint32 + | | +--:(single-interval) {single-minimum-interval}? + | | +--rw min-interval? uint32 + | +--rw demand-enabled? boolean + | | {demand-mode}? + | +--rw admin-down? boolean + | +--rw authentication! {authentication}? + | | +--rw key-chain? key-chain:key-chain-ref + | | +--rw meticulous? boolean + | +--ro path-type? identityref + | +--ro ip-encapsulation? boolean + | +--ro local-discriminator? discriminator + | +--ro remote-discriminator? discriminator + | +--ro remote-multiplier? multiplier + | +--ro demand-capability? boolean + | | {demand-mode}? + | +--ro source-port? inet:port-number + | +--ro dest-port? inet:port-number + | +--ro session-running + | | +--ro session-index? uint32 + | | +--ro local-state? state + | | +--ro remote-state? state + | | +--ro local-diagnostic? + | | | iana-bfd-types:diagnostic + | | +--ro remote-diagnostic? + | | | iana-bfd-types:diagnostic + | | +--ro remote-authenticated? boolean + | | +--ro remote-authentication-type? + | | | iana-bfd-types:auth-type {authentication}? + | | +--ro detection-mode? enumeration + | | +--ro negotiated-tx-interval? uint32 + | | +--ro negotiated-rx-interval? uint32 + | | +--ro detection-time? uint32 + | | +--ro echo-tx-interval-in-use? uint32 + | | {echo-mode}? + | +--ro session-statistics + | +--ro create-time? + | | yang:date-and-time + | +--ro last-down-time? + | | yang:date-and-time + | +--ro last-up-time? + | | yang:date-and-time + | +--ro down-count? yang:counter32 + | +--ro admin-down-count? yang:counter32 + | +--ro receive-packet-count? yang:counter64 + | +--ro send-packet-count? yang:counter64 + | +--ro receive-invalid-packet-count? yang:counter64 + | +--ro send-failed-packet-count? yang:counter64 + +--rw interfaces* [interface] + +--rw interface if:interface-ref + +--rw authentication! {authentication}? + +--rw key-chain? key-chain:key-chain-ref + +--rw meticulous? boolean + + notifications: + +---n singlehop-notification + +--ro local-discr? discriminator + +--ro remote-discr? discriminator + +--ro new-state? state + +--ro state-change-reason? iana-bfd-types:diagnostic + +--ro time-of-last-state-change? yang:date-and-time + +--ro dest-addr? inet:ip-address + +--ro source-addr? inet:ip-address + +--ro session-index? uint32 + +--ro path-type? identityref + +--ro interface? if:interface-ref + +--ro echo-enabled? boolean + +2.7. BFD IP Multihop Hierarchy + + An "ip-mh" node is added under the "bfd" node in "control-plane- + protocol". The configuration data and operational state data for + each BFD IP multihop session are under this "ip-mh" node. In the + operational state model, we support multiple BFD multihop sessions + per remote address (ECMP); the local discriminator is used as the + key. + + module: ietf-bfd-ip-mh + augment /rt:routing/rt:control-plane-protocols + /rt:control-plane-protocol/bfd:bfd: + +--rw ip-mh + +--ro summary + | +--ro number-of-sessions? yang:gauge32 + | +--ro number-of-sessions-up? yang:gauge32 + | +--ro number-of-sessions-down? yang:gauge32 + | +--ro number-of-sessions-admin-down? yang:gauge32 + +--rw session-groups + +--rw session-group* [source-addr dest-addr] + +--rw source-addr inet:ip-address + +--rw dest-addr inet:ip-address + +--rw local-multiplier? multiplier + +--rw (interval-config-type)? + | +--:(tx-rx-intervals) + | | +--rw desired-min-tx-interval? uint32 + | | +--rw required-min-rx-interval? uint32 + | +--:(single-interval) {single-minimum-interval}? + | +--rw min-interval? uint32 + +--rw demand-enabled? boolean + | {demand-mode}? + +--rw admin-down? boolean + +--rw authentication! {authentication}? + | +--rw key-chain? key-chain:key-chain-ref + | +--rw meticulous? boolean + +--rw tx-ttl? bfd-types:hops + +--rw rx-ttl bfd-types:hops + +--ro sessions* [] + +--ro path-type? identityref + +--ro ip-encapsulation? boolean + +--ro local-discriminator? discriminator + +--ro remote-discriminator? discriminator + +--ro remote-multiplier? multiplier + +--ro demand-capability? boolean {demand-mode}? + +--ro source-port? inet:port-number + +--ro dest-port? inet:port-number + +--ro session-running + | +--ro session-index? uint32 + | +--ro local-state? state + | +--ro remote-state? state + | +--ro local-diagnostic? + | | iana-bfd-types:diagnostic + | +--ro remote-diagnostic? + | | iana-bfd-types:diagnostic + | +--ro remote-authenticated? boolean + | +--ro remote-authentication-type? + | | iana-bfd-types:auth-type {authentication}? + | +--ro detection-mode? enumeration + | +--ro negotiated-tx-interval? uint32 + | +--ro negotiated-rx-interval? uint32 + | +--ro detection-time? uint32 + | +--ro echo-tx-interval-in-use? uint32 + | {echo-mode}? + +--ro session-statistics + +--ro create-time? + | yang:date-and-time + +--ro last-down-time? + | yang:date-and-time + +--ro last-up-time? + | yang:date-and-time + +--ro down-count? + | yang:counter32 + +--ro admin-down-count? + | yang:counter32 + +--ro receive-packet-count? + | yang:counter64 + +--ro send-packet-count? + | yang:counter64 + +--ro receive-invalid-packet-count? + | yang:counter64 + +--ro send-failed-packet-count? + yang:counter64 + + notifications: + +---n multihop-notification + +--ro local-discr? discriminator + +--ro remote-discr? discriminator + +--ro new-state? state + +--ro state-change-reason? iana-bfd-types:diagnostic + +--ro time-of-last-state-change? yang:date-and-time + +--ro dest-addr? inet:ip-address + +--ro source-addr? inet:ip-address + +--ro session-index? uint32 + +--ro path-type? identityref + +2.8. BFD-over-LAG Hierarchy + + A "lag" node is added under the "bfd" node in "control-plane- + protocol". The configuration data and operational state data for + each BFD LAG session are under this "lag" node. + + module: ietf-bfd-lag + augment /rt:routing/rt:control-plane-protocols + /rt:control-plane-protocol/bfd:bfd: + +--rw lag + +--rw micro-bfd-ipv4-session-statistics + | +--ro summary + | +--ro number-of-sessions? yang:gauge32 + | +--ro number-of-sessions-up? yang:gauge32 + | +--ro number-of-sessions-down? yang:gauge32 + | +--ro number-of-sessions-admin-down? yang:gauge32 + +--rw micro-bfd-ipv6-session-statistics + | +--ro summary + | +--ro number-of-sessions? yang:gauge32 + | +--ro number-of-sessions-up? yang:gauge32 + | +--ro number-of-sessions-down? yang:gauge32 + | +--ro number-of-sessions-admin-down? yang:gauge32 + +--rw sessions + +--rw session* [lag-name] + +--rw lag-name if:interface-ref + +--rw ipv4-dest-addr? + | inet:ipv4-address + +--rw ipv6-dest-addr? + | inet:ipv6-address + +--rw local-multiplier? multiplier + +--rw (interval-config-type)? + | +--:(tx-rx-intervals) + | | +--rw desired-min-tx-interval? uint32 + | | +--rw required-min-rx-interval? uint32 + | +--:(single-interval) {single-minimum-interval}? + | +--rw min-interval? uint32 + +--rw demand-enabled? boolean + | {demand-mode}? + +--rw admin-down? boolean + +--rw authentication! {authentication}? + | +--rw key-chain? key-chain:key-chain-ref + | +--rw meticulous? boolean + +--rw use-ipv4? boolean + +--rw use-ipv6? boolean + +--ro member-links* [member-link] + +--ro member-link if:interface-ref + +--ro micro-bfd-ipv4 + | +--ro path-type? identityref + | +--ro ip-encapsulation? boolean + | +--ro local-discriminator? discriminator + | +--ro remote-discriminator? discriminator + | +--ro remote-multiplier? multiplier + | +--ro demand-capability? boolean + | | {demand-mode}? + | +--ro source-port? inet:port-number + | +--ro dest-port? inet:port-number + | +--ro session-running + | | +--ro session-index? uint32 + | | +--ro local-state? state + | | +--ro remote-state? state + | | +--ro local-diagnostic? + | | | iana-bfd-types:diagnostic + | | +--ro remote-diagnostic? + | | | iana-bfd-types:diagnostic + | | +--ro remote-authenticated? boolean + | | +--ro remote-authentication-type? + | | | iana-bfd-types:auth-type + | | | {authentication}? + | | +--ro detection-mode? enumeration + | | +--ro negotiated-tx-interval? uint32 + | | +--ro negotiated-rx-interval? uint32 + | | +--ro detection-time? uint32 + | | +--ro echo-tx-interval-in-use? uint32 + | | {echo-mode}? + | +--ro session-statistics + | +--ro create-time? + | | yang:date-and-time + | +--ro last-down-time? + | | yang:date-and-time + | +--ro last-up-time? + | | yang:date-and-time + | +--ro down-count? + | | yang:counter32 + | +--ro admin-down-count? + | | yang:counter32 + | +--ro receive-packet-count? + | | yang:counter64 + | +--ro send-packet-count? + | | yang:counter64 + | +--ro receive-invalid-packet-count? + | | yang:counter64 + | +--ro send-failed-packet-count? + | yang:counter64 + +--ro micro-bfd-ipv6 + +--ro path-type? identityref + +--ro ip-encapsulation? boolean + +--ro local-discriminator? discriminator + +--ro remote-discriminator? discriminator + +--ro remote-multiplier? multiplier + +--ro demand-capability? boolean + | {demand-mode}? + +--ro source-port? inet:port-number + +--ro dest-port? inet:port-number + +--ro session-running + | +--ro session-index? uint32 + | +--ro local-state? state + | +--ro remote-state? state + | +--ro local-diagnostic? + | | iana-bfd-types:diagnostic + | +--ro remote-diagnostic? + | | iana-bfd-types:diagnostic + | +--ro remote-authenticated? boolean + | +--ro remote-authentication-type? + | | iana-bfd-types:auth-type + | | {authentication}? + | +--ro detection-mode? enumeration + | +--ro negotiated-tx-interval? uint32 + | +--ro negotiated-rx-interval? uint32 + | +--ro detection-time? uint32 + | +--ro echo-tx-interval-in-use? uint32 + | {echo-mode}? + +--ro session-statistics + +--ro create-time? + | yang:date-and-time + +--ro last-down-time? + | yang:date-and-time + +--ro last-up-time? + | yang:date-and-time + +--ro down-count? + | yang:counter32 + +--ro admin-down-count? + | yang:counter32 + +--ro receive-packet-count? + | yang:counter64 + +--ro send-packet-count? + | yang:counter64 + +--ro receive-invalid-packet-count? + | yang:counter64 + +--ro send-failed-packet-count? + yang:counter64 + + notifications: + +---n lag-notification + +--ro local-discr? discriminator + +--ro remote-discr? discriminator + +--ro new-state? state + +--ro state-change-reason? iana-bfd-types:diagnostic + +--ro time-of-last-state-change? yang:date-and-time + +--ro dest-addr? inet:ip-address + +--ro source-addr? inet:ip-address + +--ro session-index? uint32 + +--ro path-type? identityref + +--ro lag-name? if:interface-ref + +--ro member-link? if:interface-ref + +2.9. BFD-over-MPLS-LSPs Hierarchy + + An "mpls" node is added under the "bfd" node in "control-plane- + protocol". The configuration is per MPLS FEC under this "mpls" node. + In the operational state model, we support multiple BFD sessions per + MPLS FEC (ECMP); the local discriminator is used as the key. The + "mpls" node can be used in a network device (top level) or can be + mounted in an LNE or network instance. + + module: ietf-bfd-mpls + augment /rt:routing/rt:control-plane-protocols + /rt:control-plane-protocol/bfd:bfd: + +--rw mpls + +--ro summary + | +--ro number-of-sessions? yang:gauge32 + | +--ro number-of-sessions-up? yang:gauge32 + | +--ro number-of-sessions-down? yang:gauge32 + | +--ro number-of-sessions-admin-down? yang:gauge32 + +--rw egress + | +--rw enabled? boolean + | +--rw local-multiplier? multiplier + | +--rw (interval-config-type)? + | | +--:(tx-rx-intervals) + | | | +--rw desired-min-tx-interval? uint32 + | | | +--rw required-min-rx-interval? uint32 + | | +--:(single-interval) {single-minimum-interval}? + | | +--rw min-interval? uint32 + | +--rw authentication! {authentication}? + | +--rw key-chain? key-chain:key-chain-ref + | +--rw meticulous? boolean + +--rw session-groups + +--rw session-group* [mpls-fec] + +--rw mpls-fec inet:ip-prefix + +--rw local-multiplier? multiplier + +--rw (interval-config-type)? + | +--:(tx-rx-intervals) + | | +--rw desired-min-tx-interval? uint32 + | | +--rw required-min-rx-interval? uint32 + | +--:(single-interval) {single-minimum-interval}? + | +--rw min-interval? uint32 + +--rw demand-enabled? boolean + | {demand-mode}? + +--rw admin-down? boolean + +--rw authentication! {authentication}? + | +--rw key-chain? key-chain:key-chain-ref + | +--rw meticulous? boolean + +--ro sessions* [] + +--ro path-type? identityref + +--ro ip-encapsulation? boolean + +--ro local-discriminator? discriminator + +--ro remote-discriminator? discriminator + +--ro remote-multiplier? multiplier + +--ro demand-capability? boolean {demand-mode}? + +--ro source-port? inet:port-number + +--ro dest-port? inet:port-number + +--ro session-running + | +--ro session-index? uint32 + | +--ro local-state? state + | +--ro remote-state? state + | +--ro local-diagnostic? + | | iana-bfd-types:diagnostic + | +--ro remote-diagnostic? + | | iana-bfd-types:diagnostic + | +--ro remote-authenticated? boolean + | +--ro remote-authentication-type? + | | iana-bfd-types:auth-type {authentication}? + | +--ro detection-mode? enumeration + | +--ro negotiated-tx-interval? uint32 + | +--ro negotiated-rx-interval? uint32 + | +--ro detection-time? uint32 + | +--ro echo-tx-interval-in-use? uint32 + | {echo-mode}? + +--ro session-statistics + | +--ro create-time? + | | yang:date-and-time + | +--ro last-down-time? + | | yang:date-and-time + | +--ro last-up-time? + | | yang:date-and-time + | +--ro down-count? + | | yang:counter32 + | +--ro admin-down-count? + | | yang:counter32 + | +--ro receive-packet-count? + | | yang:counter64 + | +--ro send-packet-count? + | | yang:counter64 + | +--ro receive-invalid-packet-count? + | | yang:counter64 + | +--ro send-failed-packet-count? + | yang:counter64 + +--ro mpls-dest-address? inet:ip-address + + notifications: + +---n mpls-notification + +--ro local-discr? discriminator + +--ro remote-discr? discriminator + +--ro new-state? state + +--ro state-change-reason? iana-bfd-types:diagnostic + +--ro time-of-last-state-change? yang:date-and-time + +--ro dest-addr? inet:ip-address + +--ro source-addr? inet:ip-address + +--ro session-index? uint32 + +--ro path-type? identityref + +--ro mpls-dest-address? inet:ip-address + +2.10. Interaction with Other YANG Modules + + "Generic YANG Data Model for the Management of Operations, + Administration, and Maintenance (OAM) Protocols That Use + Connectionless Communications" [RFC8532] describes how the Layer- + Independent OAM Management in the Multi-Layer Environment (LIME) + connectionless OAM model could be extended to support BFD. + + Also, the operation of the BFD data model depends on configuration + parameters that are defined in other YANG modules. + +2.10.1. "ietf-interfaces" Module + + The following boolean configuration is defined in "A YANG Data Model + for Interface Management" [RFC8343]: + + /if:interfaces/if:interface/if:enabled + If this configuration is set to "false", no BFD packets can be + transmitted or received on that interface. + +2.10.2. "ietf-ip" Module + + The following boolean configuration is defined in "A YANG Data Model + for IP Management" [RFC8344]: + + /if:interfaces/if:interface/ip:ipv4/ip:enabled + If this configuration is set to "false", no BFD IPv4 packets can + be transmitted or received on that interface. + + /if:interfaces/if:interface/ip:ipv4/ip:forwarding + If this configuration is set to "false", no BFD IPv4 packets can + be transmitted or received on that interface. + + /if:interfaces/if:interface/ip:ipv6/ip:enabled + If this configuration is set to "false", no BFD IPv6 packets can + be transmitted or received on that interface. + + /if:interfaces/if:interface/ip:ipv6/ip:forwarding + If this configuration is set to "false", no BFD IPv6 packets can + be transmitted or received on that interface. + +2.10.3. "ietf-mpls" Module + + The following boolean configuration is defined in "A YANG Data Model + for MPLS Base" [RFC8960]: + + /rt:routing/mpls:mpls/mpls:interfaces/mpls:interface/ + mpls:mpls-enabled + If this configuration is set to "false", no BFD MPLS packets can + be transmitted or received on that interface. + +2.11. IANA BFD YANG Module + + This YANG module imports definitions from [RFC5880]. It references + [RFC5880] and [RFC6428]. + + <CODE BEGINS> file "iana-bfd-types@2021-10-21.yang" + module iana-bfd-types { + yang-version 1.1; + namespace "urn:ietf:params:xml:ns:yang:iana-bfd-types"; + prefix iana-bfd-types; + + organization + "IANA"; + contact + "Internet Assigned Numbers Authority + + Postal: ICANN + 12025 Waterfront Drive, Suite 300 + Los Angeles, CA 90094-2536 + United States of America + Tel: +1 310 301 5800 + <mailto:iana@iana.org>"; + description + "This module defines YANG data types for IANA-registered + BFD parameters. + + This YANG module is maintained by IANA and reflects the + 'BFD Diagnostic Codes' and 'BFD Authentication Types' + registries. + + Copyright (c) 2021 IETF Trust and the persons identified as + authors of the code. All rights reserved. + + Redistribution and use in source and binary forms, with or + without modification, is permitted pursuant to, and subject to + the license terms contained in, the Simplified BSD License set + forth in Section 4.c of the IETF Trust's Legal Provisions + Relating to IETF Documents + (https://trustee.ietf.org/license-info). + + This version of this YANG module is part of RFC 9127; see the + RFC itself for full legal notices."; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + + revision 2021-10-21 { + description + "Initial revision."; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + + /* + * Type definitions + */ + + typedef diagnostic { + type enumeration { + enum none { + value 0; + description + "No Diagnostic."; + } + enum control-expiry { + value 1; + description + "Control Detection Time Expired."; + } + enum echo-failed { + value 2; + description + "Echo Function Failed."; + } + enum neighbor-down { + value 3; + description + "Neighbor Signaled Session Down."; + } + enum forwarding-reset { + value 4; + description + "Forwarding Plane Reset."; + } + enum path-down { + value 5; + description + "Path Down."; + } + enum concatenated-path-down { + value 6; + description + "Concatenated Path Down."; + } + enum admin-down { + value 7; + description + "Administratively Down."; + } + enum reverse-concatenated-path-down { + value 8; + description + "Reverse Concatenated Path Down."; + } + enum mis-connectivity-defect { + value 9; + description + "Mis-connectivity defect."; + reference + "RFC 5880: Bidirectional Forwarding Detection (BFD) + RFC 6428: Proactive Connectivity Verification, Continuity + Check, and Remote Defect Indication for the MPLS Transport + Profile"; + } + } + description + "BFD diagnostic codes as defined in RFC 5880. Values are + maintained in the 'BFD Diagnostic Codes' IANA registry. + Range is 0 to 31."; + reference + "RFC 5880: Bidirectional Forwarding Detection (BFD)"; + } + + typedef auth-type { + type enumeration { + enum reserved { + value 0; + description + "Reserved."; + } + enum simple-password { + value 1; + description + "Simple Password."; + } + enum keyed-md5 { + value 2; + description + "Keyed MD5."; + } + enum meticulous-keyed-md5 { + value 3; + description + "Meticulous Keyed MD5."; + } + enum keyed-sha1 { + value 4; + description + "Keyed SHA1."; + } + enum meticulous-keyed-sha1 { + value 5; + description + "Meticulous Keyed SHA1."; + } + } + description + "BFD authentication type as defined in RFC 5880. Values are + maintained in the 'BFD Authentication Types' IANA registry. + Range is 0 to 255."; + reference + "RFC 5880: Bidirectional Forwarding Detection (BFD)"; + } + } + <CODE ENDS> + +2.12. BFD Types YANG Module + + This YANG module imports typedefs from [RFC6991] and [RFC8177]. It + also imports definitions from [RFC5880], [RFC5881], [RFC5883], + [RFC5884], and [RFC7130], as well as the "control-plane-protocol" + identity from [RFC8349]. + + <CODE BEGINS> file "ietf-bfd-types@2021-10-21.yang" + module ietf-bfd-types { + yang-version 1.1; + namespace "urn:ietf:params:xml:ns:yang:ietf-bfd-types"; + prefix bfd-types; + + import iana-bfd-types { + prefix iana-bfd-types; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + import ietf-inet-types { + prefix inet; + reference + "RFC 6991: Common YANG Data Types"; + } + import ietf-yang-types { + prefix yang; + reference + "RFC 6991: Common YANG Data Types"; + } + import ietf-routing { + prefix rt; + reference + "RFC 8349: A YANG Data Model for Routing Management + (NMDA Version)"; + } + import ietf-key-chain { + prefix key-chain; + reference + "RFC 8177: YANG Data Model for Key Chains"; + } + + organization + "IETF BFD Working Group"; + contact + "WG Web: <https://datatracker.ietf.org/wg/bfd/> + WG List: <mailto:rtg-bfd@ietf.org> + + Editor: Reshad Rahman + <mailto:reshad@yahoo.com> + + Editor: Lianshu Zheng + <mailto:veronique_cheng@hotmail.com> + + Editor: Mahesh Jethanandani + <mailto:mjethanandani@gmail.com>"; + description + "This module contains a collection of BFD-specific YANG data type + definitions, as per RFC 5880, and also groupings that are common + to other BFD YANG modules. + + Copyright (c) 2021 IETF Trust and the persons identified as + authors of the code. All rights reserved. + + Redistribution and use in source and binary forms, with or + without modification, is permitted pursuant to, and subject to + the license terms contained in, the Simplified BSD License set + forth in Section 4.c of the IETF Trust's Legal Provisions + Relating to IETF Documents + (https://trustee.ietf.org/license-info). + + This version of this YANG module is part of RFC 9127; see the + RFC itself for full legal notices."; + reference + "RFC 5880: Bidirectional Forwarding Detection (BFD) + RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + + revision 2021-10-21 { + description + "Initial revision."; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + + /* + * Feature definitions + */ + + feature single-minimum-interval { + description + "This feature indicates that the server supports configuration + of one minimum interval value that is used for both transmit + and receive minimum intervals."; + } + + feature authentication { + description + "This feature indicates that the server supports BFD + authentication."; + reference + "RFC 5880: Bidirectional Forwarding Detection (BFD), + Section 6.7"; + } + + feature demand-mode { + description + "This feature indicates that the server supports BFD Demand + mode."; + reference + "RFC 5880: Bidirectional Forwarding Detection (BFD), + Section 6.6"; + } + + feature echo-mode { + description + "This feature indicates that the server supports BFD Echo + mode."; + reference + "RFC 5880: Bidirectional Forwarding Detection (BFD), + Section 6.4"; + } + + /* + * Identity definitions + */ + + identity bfdv1 { + base rt:control-plane-protocol; + description + "BFD protocol version 1."; + reference + "RFC 5880: Bidirectional Forwarding Detection (BFD)"; + } + + identity path-type { + description + "Base identity for the BFD path type. The path type indicates + the type of path on which BFD is running."; + } + + identity path-ip-sh { + base path-type; + description + "BFD on IP single-hop."; + reference + "RFC 5881: Bidirectional Forwarding Detection (BFD) + for IPv4 and IPv6 (Single Hop)"; + } + + identity path-ip-mh { + base path-type; + description + "BFD on IP multihop paths."; + reference + "RFC 5883: Bidirectional Forwarding Detection (BFD) for + Multihop Paths"; + } + + identity path-mpls-te { + base path-type; + description + "BFD on MPLS Traffic Engineering."; + reference + "RFC 5884: Bidirectional Forwarding Detection (BFD) + for MPLS Label Switched Paths (LSPs)"; + } + + identity path-mpls-lsp { + base path-type; + description + "BFD on an MPLS Label Switched Path."; + reference + "RFC 5884: Bidirectional Forwarding Detection (BFD) + for MPLS Label Switched Paths (LSPs)"; + } + + identity path-lag { + base path-type; + description + "Micro-BFD on LAG member links."; + reference + "RFC 7130: Bidirectional Forwarding Detection (BFD) on + Link Aggregation Group (LAG) Interfaces"; + } + + identity encap-type { + description + "Base identity for BFD encapsulation type."; + } + + identity encap-ip { + base encap-type; + description + "BFD with IP encapsulation."; + } + + /* + * Type definitions + */ + + typedef discriminator { + type uint32; + description + "BFD Discriminator as described in RFC 5880."; + reference + "RFC 5880: Bidirectional Forwarding Detection (BFD)"; + } + + typedef state { + type enumeration { + enum adminDown { + value 0; + description + "'adminDown' state."; + } + enum down { + value 1; + description + "'Down' state."; + } + enum init { + value 2; + description + "'Init' state."; + } + enum up { + value 3; + description + "'Up' state."; + } + } + description + "BFD states as defined in RFC 5880."; + } + + typedef multiplier { + type uint8 { + range "1..255"; + } + description + "BFD multiplier as described in RFC 5880."; + } + + typedef hops { + type uint8 { + range "1..255"; + } + description + "This corresponds to Time To Live for IPv4 and corresponds to + the hop limit for IPv6."; + } + + /* + * Groupings + */ + + grouping auth-parms { + description + "Grouping for BFD authentication parameters + (see Section 6.7 of RFC 5880)."; + container authentication { + if-feature "authentication"; + presence "Enables BFD authentication (see Section 6.7 + of RFC 5880)."; + description + "Parameters for BFD authentication."; + reference + "RFC 5880: Bidirectional Forwarding Detection (BFD), + Section 6.7"; + leaf key-chain { + type key-chain:key-chain-ref; + description + "Name of the 'key-chain' as per RFC 8177."; + } + leaf meticulous { + type boolean; + description + "Enables a meticulous mode as per Section 6.7 of + RFC 5880."; + } + } + } + + grouping base-cfg-parms { + description + "BFD grouping for base configuration parameters."; + leaf local-multiplier { + type multiplier; + default "3"; + description + "Multiplier transmitted by the local system."; + } + choice interval-config-type { + default "tx-rx-intervals"; + description + "Two interval values or one value used for both transmit and + receive."; + case tx-rx-intervals { + leaf desired-min-tx-interval { + type uint32; + units "microseconds"; + default "1000000"; + description + "Desired minimum transmit interval of control packets."; + } + leaf required-min-rx-interval { + type uint32; + units "microseconds"; + default "1000000"; + description + "Required minimum receive interval of control packets."; + } + } + case single-interval { + if-feature "single-minimum-interval"; + leaf min-interval { + type uint32; + units "microseconds"; + default "1000000"; + description + "Desired minimum transmit interval and required + minimum receive interval of control packets."; + } + } + } + } + + grouping client-cfg-parms { + description + "BFD grouping for configuration parameters + used by BFD clients, e.g., IGP or MPLS."; + leaf enabled { + type boolean; + default "false"; + description + "Indicates whether BFD is enabled."; + } + uses base-cfg-parms; + } + + grouping common-cfg-parms { + description + "BFD grouping for common configuration parameters."; + uses base-cfg-parms; + leaf demand-enabled { + if-feature "demand-mode"; + type boolean; + default "false"; + description + "To enable Demand mode."; + } + leaf admin-down { + type boolean; + default "false"; + description + "Indicates whether the BFD session is administratively + down."; + } + uses auth-parms; + } + + grouping all-session { + description + "BFD session operational information."; + leaf path-type { + type identityref { + base path-type; + } + config false; + description + "BFD path type. This indicates the path type that BFD is + running on."; + } + leaf ip-encapsulation { + type boolean; + config false; + description + "Indicates whether BFD encapsulation uses IP."; + } + leaf local-discriminator { + type discriminator; + config false; + description + "Local discriminator."; + } + leaf remote-discriminator { + type discriminator; + config false; + description + "Remote discriminator."; + } + leaf remote-multiplier { + type multiplier; + config false; + description + "Remote multiplier."; + } + leaf demand-capability { + if-feature "demand-mode"; + type boolean; + config false; + description + "Local Demand mode capability."; + } + leaf source-port { + when "../ip-encapsulation = 'true'" { + description + "Source port valid only when IP encapsulation is used."; + } + type inet:port-number; + config false; + description + "Source UDP port."; + } + leaf dest-port { + when "../ip-encapsulation = 'true'" { + description + "Destination port valid only when IP encapsulation + is used."; + } + type inet:port-number; + config false; + description + "Destination UDP port."; + } + container session-running { + config false; + description + "BFD 'session-running' information."; + leaf session-index { + type uint32; + description + "An index used to uniquely identify BFD sessions."; + } + leaf local-state { + type state; + description + "Local state."; + } + leaf remote-state { + type state; + description + "Remote state."; + } + leaf local-diagnostic { + type iana-bfd-types:diagnostic; + description + "Local diagnostic."; + } + leaf remote-diagnostic { + type iana-bfd-types:diagnostic; + description + "Remote diagnostic."; + } + leaf remote-authenticated { + type boolean; + description + "Indicates whether incoming BFD control packets are + authenticated."; + } + leaf remote-authentication-type { + when "../remote-authenticated = 'true'" { + description + "Only valid when incoming BFD control packets are + authenticated."; + } + if-feature "authentication"; + type iana-bfd-types:auth-type; + description + "Authentication type of incoming BFD control packets."; + } + leaf detection-mode { + type enumeration { + enum async-with-echo { + value 1; + description + "Async with echo."; + } + enum async-without-echo { + value 2; + description + "Async without echo."; + } + enum demand-with-echo { + value 3; + description + "Demand with echo."; + } + enum demand-without-echo { + value 4; + description + "Demand without echo."; + } + } + description + "Detection mode."; + } + leaf negotiated-tx-interval { + type uint32; + units "microseconds"; + description + "Negotiated transmit interval."; + } + leaf negotiated-rx-interval { + type uint32; + units "microseconds"; + description + "Negotiated receive interval."; + } + leaf detection-time { + type uint32; + units "microseconds"; + description + "Detection time."; + } + leaf echo-tx-interval-in-use { + when "../../path-type = 'bfd-types:path-ip-sh'" { + description + "Echo is supported for IP single-hop only."; + } + if-feature "echo-mode"; + type uint32; + units "microseconds"; + description + "Echo transmit interval in use."; + } + } + container session-statistics { + config false; + description + "BFD per-session statistics."; + leaf create-time { + type yang:date-and-time; + description + "Time and date when this session was created."; + } + leaf last-down-time { + type yang:date-and-time; + description + "Time and date of the last time this session went down."; + } + leaf last-up-time { + type yang:date-and-time; + description + "Time and date of the last time this session went up."; + } + leaf down-count { + type yang:counter32; + description + "The number of times this session has transitioned to the + 'down' state."; + } + leaf admin-down-count { + type yang:counter32; + description + "The number of times this session has transitioned to the + 'admin-down' state."; + } + leaf receive-packet-count { + type yang:counter64; + description + "Count of received packets in this session. This includes + valid and invalid received packets."; + } + leaf send-packet-count { + type yang:counter64; + description + "Count of sent packets in this session."; + } + leaf receive-invalid-packet-count { + type yang:counter64; + description + "Count of invalid received packets in this session."; + } + leaf send-failed-packet-count { + type yang:counter64; + description + "Count of packets that failed to be sent in this session."; + } + } + } + + grouping session-statistics-summary { + description + "Grouping for session statistics summary."; + container summary { + config false; + description + "BFD session statistics summary."; + leaf number-of-sessions { + type yang:gauge32; + description + "Number of BFD sessions."; + } + leaf number-of-sessions-up { + type yang:gauge32; + description + "Number of BFD sessions currently in the 'Up' state + (as defined in RFC 5880)."; + } + leaf number-of-sessions-down { + type yang:gauge32; + description + "Number of BFD sessions currently in the 'Down' or 'Init' + state but not 'adminDown' (as defined in RFC 5880)."; + } + leaf number-of-sessions-admin-down { + type yang:gauge32; + description + "Number of BFD sessions currently in the 'adminDown' state + (as defined in RFC 5880)."; + } + } + } + + grouping notification-parms { + description + "This group describes common parameters that will be sent + as part of BFD notifications."; + leaf local-discr { + type discriminator; + description + "BFD local discriminator."; + } + leaf remote-discr { + type discriminator; + description + "BFD remote discriminator."; + } + leaf new-state { + type state; + description + "Current BFD state."; + } + leaf state-change-reason { + type iana-bfd-types:diagnostic; + description + "Reason for the BFD state change."; + } + leaf time-of-last-state-change { + type yang:date-and-time; + description + "Calendar time of the most recent previous state change."; + } + leaf dest-addr { + type inet:ip-address; + description + "BFD peer address."; + } + leaf source-addr { + type inet:ip-address; + description + "BFD local address."; + } + leaf session-index { + type uint32; + description + "An index used to uniquely identify BFD sessions."; + } + leaf path-type { + type identityref { + base path-type; + } + description + "BFD path type."; + } + } + } + <CODE ENDS> + +2.13. BFD Top-Level YANG Module + + This YANG module imports and augments "/routing/control-plane- + protocols/control-plane-protocol" from [RFC8349]. It also references + [RFC5880]. + + <CODE BEGINS> file "ietf-bfd@2021-10-21.yang" + module ietf-bfd { + yang-version 1.1; + namespace "urn:ietf:params:xml:ns:yang:ietf-bfd"; + prefix bfd; + + import ietf-bfd-types { + prefix bfd-types; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + import ietf-routing { + prefix rt; + reference + "RFC 8349: A YANG Data Model for Routing Management + (NMDA Version)"; + } + + organization + "IETF BFD Working Group"; + contact + "WG Web: <https://datatracker.ietf.org/wg/bfd/> + WG List: <mailto:rtg-bfd@ietf.org> + + Editor: Reshad Rahman + <mailto:reshad@yahoo.com> + + Editor: Lianshu Zheng + <mailto:veronique_cheng@hotmail.com> + + Editor: Mahesh Jethanandani + <mailto:mjethanandani@gmail.com>"; + description + "This module contains the YANG definition for BFD parameters as + per RFC 5880. + + Copyright (c) 2021 IETF Trust and the persons identified as + authors of the code. All rights reserved. + + Redistribution and use in source and binary forms, with or + without modification, is permitted pursuant to, and subject to + the license terms contained in, the Simplified BSD License set + forth in Section 4.c of the IETF Trust's Legal Provisions + Relating to IETF Documents + (https://trustee.ietf.org/license-info). + + This version of this YANG module is part of RFC 9127; see the + RFC itself for full legal notices."; + reference + "RFC 5880: Bidirectional Forwarding Detection (BFD) + RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + + revision 2021-10-21 { + description + "Initial revision."; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + + augment "/rt:routing/rt:control-plane-protocols/" + + "rt:control-plane-protocol" { + when "derived-from-or-self(rt:type, 'bfd-types:bfdv1')" { + description + "This augmentation is only valid for a control-plane protocol + instance of BFD (type 'bfdv1')."; + } + description + "BFD augmentation."; + container bfd { + description + "BFD top-level container."; + uses bfd-types:session-statistics-summary; + } + } + } + <CODE ENDS> + +2.14. BFD IP Single-Hop YANG Module + + This YANG module imports "interface-ref" from [RFC8343] and typedefs + from [RFC6991]. It also imports and augments "/routing/control- + plane-protocols/control-plane-protocol" from [RFC8349], and it + references [RFC5881]. + + <CODE BEGINS> file "ietf-bfd-ip-sh@2021-10-21.yang" + module ietf-bfd-ip-sh { + yang-version 1.1; + namespace "urn:ietf:params:xml:ns:yang:ietf-bfd-ip-sh"; + prefix bfd-ip-sh; + + import ietf-bfd-types { + prefix bfd-types; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + import ietf-bfd { + prefix bfd; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + import ietf-interfaces { + prefix if; + reference + "RFC 8343: A YANG Data Model for Interface Management"; + } + import ietf-inet-types { + prefix inet; + reference + "RFC 6991: Common YANG Data Types"; + } + import ietf-routing { + prefix rt; + reference + "RFC 8349: A YANG Data Model for Routing Management + (NMDA Version)"; + } + + organization + "IETF BFD Working Group"; + contact + "WG Web: <https://datatracker.ietf.org/wg/bfd/> + WG List: <mailto:rtg-bfd@ietf.org> + + Editor: Reshad Rahman + <mailto:reshad@yahoo.com> + + Editor: Lianshu Zheng + <mailto:veronique_cheng@hotmail.com> + + Editor: Mahesh Jethanandani + <mailto:mjethanandani@gmail.com>"; + description + "This module contains the YANG definition for BFD IP single-hop + as per RFC 5881. + + Copyright (c) 2021 IETF Trust and the persons identified as + authors of the code. All rights reserved. + + Redistribution and use in source and binary forms, with or + without modification, is permitted pursuant to, and subject to + the license terms contained in, the Simplified BSD License set + forth in Section 4.c of the IETF Trust's Legal Provisions + Relating to IETF Documents + (https://trustee.ietf.org/license-info). + + This version of this YANG module is part of RFC 9127; see the + RFC itself for full legal notices."; + reference + "RFC 5881: Bidirectional Forwarding Detection (BFD) + for IPv4 and IPv6 (Single Hop) + RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + + revision 2021-10-21 { + description + "Initial revision."; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + + /* + * Augments + */ + + augment "/rt:routing/rt:control-plane-protocols/" + + "rt:control-plane-protocol/bfd:bfd" { + description + "BFD augmentation for IP single-hop."; + container ip-sh { + description + "BFD IP single-hop top-level container."; + uses bfd-types:session-statistics-summary; + container sessions { + description + "BFD IP single-hop sessions."; + list session { + key "interface dest-addr"; + description + "List of IP single-hop sessions."; + leaf interface { + type if:interface-ref; + description + "Interface on which the BFD session is running."; + } + leaf dest-addr { + type inet:ip-address; + description + "IP address of the peer."; + } + leaf source-addr { + type inet:ip-address; + description + "Local IP address."; + } + uses bfd-types:common-cfg-parms; + uses bfd-types:all-session; + } + } + list interfaces { + key "interface"; + description + "List of interfaces."; + leaf interface { + type if:interface-ref; + description + "BFD information for this interface."; + } + uses bfd-types:auth-parms; + } + } + } + + /* + * Notifications + */ + + notification singlehop-notification { + description + "Notification for BFD single-hop session state change. An + implementation may rate-limit notifications, e.g., when a + session is continuously changing state."; + uses bfd-types:notification-parms; + leaf interface { + type if:interface-ref; + description + "Interface to which this BFD session belongs."; + } + leaf echo-enabled { + type boolean; + description + "Indicates whether Echo was enabled for BFD."; + } + } + } + <CODE ENDS> + +2.15. BFD IP Multihop YANG Module + + This YANG module imports typedefs from [RFC6991]. It also imports + and augments "/routing/control-plane-protocols/control-plane- + protocol" from [RFC8349], and it references [RFC5883]. + + <CODE BEGINS> file "ietf-bfd-ip-mh@2021-10-21.yang" + module ietf-bfd-ip-mh { + yang-version 1.1; + namespace "urn:ietf:params:xml:ns:yang:ietf-bfd-ip-mh"; + prefix bfd-ip-mh; + + import ietf-bfd-types { + prefix bfd-types; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + import ietf-bfd { + prefix bfd; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + import ietf-inet-types { + prefix inet; + reference + "RFC 6991: Common YANG Data Types"; + } + import ietf-routing { + prefix rt; + reference + "RFC 8349: A YANG Data Model for Routing Management + (NMDA Version)"; + } + + organization + "IETF BFD Working Group"; + contact + "WG Web: <https://datatracker.ietf.org/wg/bfd/> + WG List: <mailto:rtg-bfd@ietf.org> + + Editor: Reshad Rahman + <mailto:reshad@yahoo.com> + + Editor: Lianshu Zheng + <mailto:veronique_cheng@hotmail.com> + + Editor: Mahesh Jethanandani + <mailto:mjethanandani@gmail.com>"; + description + "This module contains the YANG definition for BFD IP multihop + as per RFC 5883. + + Copyright (c) 2021 IETF Trust and the persons identified as + authors of the code. All rights reserved. + + Redistribution and use in source and binary forms, with or + without modification, is permitted pursuant to, and subject to + the license terms contained in, the Simplified BSD License set + forth in Section 4.c of the IETF Trust's Legal Provisions + Relating to IETF Documents + (https://trustee.ietf.org/license-info). + + This version of this YANG module is part of RFC 9127; see the + RFC itself for full legal notices."; + reference + "RFC 5883: Bidirectional Forwarding Detection (BFD) for + Multihop Paths + RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + + revision 2021-10-21 { + description + "Initial revision."; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + + /* + * Augments + */ + + augment "/rt:routing/rt:control-plane-protocols/" + + "rt:control-plane-protocol/bfd:bfd" { + description + "BFD augmentation for IP multihop."; + container ip-mh { + description + "BFD IP multihop top-level container."; + uses bfd-types:session-statistics-summary; + container session-groups { + description + "BFD IP multihop session groups."; + list session-group { + key "source-addr dest-addr"; + description + "Group of BFD IP multihop sessions (for ECMP). A + group of sessions is between one source and one + destination. Each session has a different field + in the UDP/IP header for ECMP."; + leaf source-addr { + type inet:ip-address; + description + "Local IP address."; + } + leaf dest-addr { + type inet:ip-address; + description + "IP address of the peer."; + } + uses bfd-types:common-cfg-parms; + leaf tx-ttl { + type bfd-types:hops; + default "255"; + description + "Hop count of outgoing BFD control packets."; + } + leaf rx-ttl { + type bfd-types:hops; + mandatory true; + description + "Minimum allowed hop count value for incoming BFD + control packets. Control packets whose hop count is + lower than this value are dropped."; + } + list sessions { + config false; + description + "The multiple BFD sessions between a source and a + destination."; + uses bfd-types:all-session; + } + } + } + } + } + + /* + * Notifications + */ + + notification multihop-notification { + description + "Notification for BFD multihop session state change. An + implementation may rate-limit notifications, e.g., when a + session is continuously changing state."; + uses bfd-types:notification-parms; + } + } + <CODE ENDS> + +2.16. BFD-over-LAG YANG Module + + This YANG module imports "interface-ref" from [RFC8343] and typedefs + from [RFC6991]. It also imports and augments "/routing/control- + plane-protocols/control-plane-protocol" from [RFC8349]. + Additionally, it references [RFC7130]. + + <CODE BEGINS> file "ietf-bfd-lag@2021-10-21.yang" + module ietf-bfd-lag { + yang-version 1.1; + namespace "urn:ietf:params:xml:ns:yang:ietf-bfd-lag"; + prefix bfd-lag; + + import ietf-bfd-types { + prefix bfd-types; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + import ietf-bfd { + prefix bfd; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + import ietf-interfaces { + prefix if; + reference + "RFC 8343: A YANG Data Model for Interface Management"; + } + import ietf-inet-types { + prefix inet; + reference + "RFC 6991: Common YANG Data Types"; + } + import ietf-routing { + prefix rt; + reference + "RFC 8349: A YANG Data Model for Routing Management + (NMDA Version)"; + } + + organization + "IETF BFD Working Group"; + contact + "WG Web: <https://datatracker.ietf.org/wg/bfd/> + WG List: <mailto:rtg-bfd@ietf.org> + + Editor: Reshad Rahman + <mailto:reshad@yahoo.com> + + Editor: Lianshu Zheng + <mailto:veronique_cheng@hotmail.com> + + Editor: Mahesh Jethanandani + <mailto:mjethanandani@gmail.com>"; + description + "This module contains the YANG definition for BFD-over-LAG + interfaces as per RFC 7130. + + Copyright (c) 2021 IETF Trust and the persons identified as + authors of the code. All rights reserved. + + Redistribution and use in source and binary forms, with or + without modification, is permitted pursuant to, and subject to + the license terms contained in, the Simplified BSD License set + forth in Section 4.c of the IETF Trust's Legal Provisions + Relating to IETF Documents + (https://trustee.ietf.org/license-info). + + This version of this YANG module is part of RFC 9127; see the + RFC itself for full legal notices."; + reference + "RFC 7130: Bidirectional Forwarding Detection (BFD) on + Link Aggregation Group (LAG) Interfaces + RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + + revision 2021-10-21 { + description + "Initial revision."; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + + /* + * Augments + */ + + augment "/rt:routing/rt:control-plane-protocols/" + + "rt:control-plane-protocol/bfd:bfd" { + description + "BFD augmentation for a LAG."; + container lag { + description + "BFD-over-LAG top-level container."; + container micro-bfd-ipv4-session-statistics { + description + "Micro-BFD IPv4 session counters."; + uses bfd-types:session-statistics-summary; + } + container micro-bfd-ipv6-session-statistics { + description + "Micro-BFD IPv6 session counters."; + uses bfd-types:session-statistics-summary; + } + container sessions { + description + "BFD-over-LAG sessions."; + list session { + key "lag-name"; + description + "List of BFD-over-LAG sessions."; + leaf lag-name { + type if:interface-ref; + description + "Name of the LAG."; + } + leaf ipv4-dest-addr { + type inet:ipv4-address; + description + "IPv4 address of the peer, for IPv4 micro-BFD."; + } + leaf ipv6-dest-addr { + type inet:ipv6-address; + description + "IPv6 address of the peer, for IPv6 micro-BFD."; + } + uses bfd-types:common-cfg-parms; + leaf use-ipv4 { + type boolean; + description + "Using IPv4 micro-BFD."; + } + leaf use-ipv6 { + type boolean; + description + "Using IPv6 micro-BFD."; + } + list member-links { + key "member-link"; + config false; + description + "Micro-BFD over a LAG. This represents one + member link."; + leaf member-link { + type if:interface-ref; + description + "Member link on which micro-BFD is running."; + } + container micro-bfd-ipv4 { + when "../../use-ipv4 = 'true'" { + description + "Needed only if IPv4 is used."; + } + description + "Micro-BFD IPv4 session state on a member link."; + uses bfd-types:all-session; + } + container micro-bfd-ipv6 { + when "../../use-ipv6 = 'true'" { + description + "Needed only if IPv6 is used."; + } + description + "Micro-BFD IPv6 session state on a member link."; + uses bfd-types:all-session; + } + } + } + } + } + } + + /* + * Notifications + */ + + notification lag-notification { + description + "Notification for BFD-over-LAG session state change. + An implementation may rate-limit notifications, e.g., when a + session is continuously changing state."; + uses bfd-types:notification-parms; + leaf lag-name { + type if:interface-ref; + description + "LAG interface name."; + } + leaf member-link { + type if:interface-ref; + description + "Member link on which BFD is running."; + } + } + } + <CODE ENDS> + +2.17. BFD-over-MPLS YANG Module + + This YANG module imports typedefs from [RFC6991]. It also imports + and augments "/routing/control-plane-protocols/control-plane- + protocol" from [RFC8349]. Additionally, it references [RFC5586] and + [RFC5884]. + + <CODE BEGINS> file "ietf-bfd-mpls@2021-10-21.yang" + module ietf-bfd-mpls { + yang-version 1.1; + namespace "urn:ietf:params:xml:ns:yang:ietf-bfd-mpls"; + prefix bfd-mpls; + + import ietf-bfd-types { + prefix bfd-types; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + import ietf-bfd { + prefix bfd; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + import ietf-inet-types { + prefix inet; + reference + "RFC 6991: Common YANG Data Types"; + } + import ietf-routing { + prefix rt; + reference + "RFC 8349: A YANG Data Model for Routing Management + (NMDA Version)"; + } + + organization + "IETF BFD Working Group"; + contact + "WG Web: <https://datatracker.ietf.org/wg/bfd/> + WG List: <mailto:rtg-bfd@ietf.org> + + Editor: Reshad Rahman + <mailto:reshad@yahoo.com> + + Editor: Lianshu Zheng + <mailto:veronique_cheng@hotmail.com> + + Editor: Mahesh Jethanandani + <mailto:mjethanandani@gmail.com>"; + description + "This module contains the YANG definition for BFD parameters for + MPLS LSPs as per RFC 5884. + + Copyright (c) 2021 IETF Trust and the persons identified as + authors of the code. All rights reserved. + + Redistribution and use in source and binary forms, with or + without modification, is permitted pursuant to, and subject to + the license terms contained in, the Simplified BSD License set + forth in Section 4.c of the IETF Trust's Legal Provisions + Relating to IETF Documents + (https://trustee.ietf.org/license-info). + + This version of this YANG module is part of RFC 9127; see the + RFC itself for full legal notices."; + reference + "RFC 5884: Bidirectional Forwarding Detection (BFD) + for MPLS Label Switched Paths (LSPs) + RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + + revision 2021-10-21 { + description + "Initial revision."; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + + /* + * Identity definitions + */ + + identity encap-gach { + base bfd-types:encap-type; + description + "BFD with G-ACh encapsulation as per RFC 5586."; + reference + "RFC 5586: MPLS Generic Associated Channel"; + } + + identity encap-ip-gach { + base bfd-types:encap-type; + description + "BFD with IP and G-ACh encapsulation as per RFC 5586."; + } + + /* + * Groupings + */ + + grouping encap-cfg { + description + "Configuration for BFD encapsulation."; + leaf encap { + type identityref { + base bfd-types:encap-type; + } + default "bfd-types:encap-ip"; + description + "BFD encapsulation."; + } + } + + grouping mpls-dest-address { + description + "Destination address as per RFC 5884."; + reference + "RFC 5884: Bidirectional Forwarding Detection (BFD) + for MPLS Label Switched Paths (LSPs)"; + leaf mpls-dest-address { + type inet:ip-address; + config false; + description + "Destination address as per RFC 5884. + Needed if IP encapsulation is used."; + } + } + + /* + * Augments + */ + + augment "/rt:routing/rt:control-plane-protocols/" + + "rt:control-plane-protocol/bfd:bfd" { + description + "BFD augmentation for MPLS."; + container mpls { + description + "BFD MPLS top-level container."; + uses bfd-types:session-statistics-summary; + container egress { + description + "Egress configuration."; + uses bfd-types:client-cfg-parms; + uses bfd-types:auth-parms; + } + container session-groups { + description + "BFD-over-MPLS session groups."; + list session-group { + key "mpls-fec"; + description + "Group of BFD MPLS sessions (for ECMP). A group of + sessions is for one FEC. Each session has a different + field in the UDP/IP header for ECMP."; + leaf mpls-fec { + type inet:ip-prefix; + description + "MPLS FEC."; + } + uses bfd-types:common-cfg-parms; + list sessions { + config false; + description + "The BFD sessions for an MPLS FEC. The local + discriminator is unique for each session in the + group."; + uses bfd-types:all-session; + uses bfd-mpls:mpls-dest-address; + } + } + } + } + } + + /* + * Notifications + */ + + notification mpls-notification { + description + "Notification for BFD-over-MPLS FEC session state change. + An implementation may rate-limit notifications, e.g., when a + session is continuously changing state."; + uses bfd-types:notification-parms; + leaf mpls-dest-address { + type inet:ip-address; + description + "Destination address as per RFC 5884. + Needed if IP encapsulation is used."; + } + } + } + <CODE ENDS> + +3. Data Model Examples + + This section presents some simple and illustrative examples of how to + configure BFD. + + The examples are represented in XML [W3C.REC-xml-20081126]. + +3.1. IP Single-Hop + + The following is an example configuration for a BFD IP single-hop + session. The desired transmit interval and the required receive + interval are both set to 10 ms. + + <?xml version="1.0" encoding="UTF-8"?> + <config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> + <interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"> + <interface> + <name>eth0</name> + <type xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type"> + ianaift:ethernetCsmacd + </type> + </interface> + </interfaces> + <routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"> + <control-plane-protocols> + <control-plane-protocol> + <type xmlns:bfd-types= + "urn:ietf:params:xml:ns:yang:ietf-bfd-types"> + bfd-types:bfdv1 + </type> + <name>name:BFD</name> + <bfd xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd"> + <ip-sh xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd-ip-sh"> + <sessions> + <session> + <interface>eth0</interface> + <dest-addr>2001:db8:0:113::101</dest-addr> + <desired-min-tx-interval> + 10000 + </desired-min-tx-interval> + <required-min-rx-interval> + 10000 + </required-min-rx-interval> + </session> + </sessions> + </ip-sh> + </bfd> + </control-plane-protocol> + </control-plane-protocols> + </routing> + </config> + +3.2. IP Multihop + + The following is an example configuration for a BFD IP multihop + session group. The desired transmit interval and the required + receive interval are both set to 150 ms. + + <?xml version="1.0" encoding="UTF-8"?> + <config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> + <routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"> + <control-plane-protocols> + <control-plane-protocol> + <type xmlns:bfd-types= + "urn:ietf:params:xml:ns:yang:ietf-bfd-types"> + bfd-types:bfdv1 + </type> + <name>name:BFD</name> + <bfd xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd"> + <ip-mh xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd-ip-mh"> + <session-groups> + <session-group> + <source-addr>2001:db8:0:113::103</source-addr> + <dest-addr>2001:db8:0:114::100</dest-addr> + <desired-min-tx-interval> + 150000 + </desired-min-tx-interval> + <required-min-rx-interval> + 150000 + </required-min-rx-interval> + <rx-ttl>240</rx-ttl> + </session-group> + </session-groups> + </ip-mh> + </bfd> + </control-plane-protocol> + </control-plane-protocols> + </routing> + </config> + +3.3. LAG + + The following is an example of BFD configuration for a LAG session. + In this case, an interface named "Bundle-Ether1" of interface type + "ieee8023adLag" has a desired transmit interval and required receive + interval set to 10 ms. + + <?xml version="1.0" encoding="UTF-8"?> + <config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> + <interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"> + <interface> + <name>Bundle-Ether1</name> + <type xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type"> + ianaift:ieee8023adLag + </type> + </interface> + </interfaces> + <routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"> + <control-plane-protocols> + <control-plane-protocol> + <type xmlns:bfd-types= + "urn:ietf:params:xml:ns:yang:ietf-bfd-types"> + bfd-types:bfdv1 + </type> + <name>name:BFD</name> + <bfd xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd"> + <lag xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd-lag"> + <sessions> + <session> + <lag-name>Bundle-Ether1</lag-name> + <ipv6-dest-addr>2001:db8:112::16</ipv6-dest-addr> + <desired-min-tx-interval> + 100000 + </desired-min-tx-interval> + <required-min-rx-interval> + 100000 + </required-min-rx-interval> + <use-ipv6>true</use-ipv6> + </session> + </sessions> + </lag> + </bfd> + </control-plane-protocol> + </control-plane-protocols> + </routing> + </config> + +3.4. MPLS + + The following is an example of BFD configured for an MPLS LSP. In + this case, the desired transmit interval and required receive + interval are both set to 250 ms. + + <?xml version="1.0" encoding="UTF-8"?> + <config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> + <routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"> + <control-plane-protocols> + <control-plane-protocol> + <type xmlns:bfd-types= + "urn:ietf:params:xml:ns:yang:ietf-bfd-types"> + bfd-types:bfdv1 + </type> + <name>name:BFD</name> + <bfd xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd"> + <mpls xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd-mpls"> + <session-groups> + <session-group> + <mpls-fec>2001:db8:114::/116</mpls-fec> + <desired-min-tx-interval> + 250000 + </desired-min-tx-interval> + <required-min-rx-interval> + 250000 + </required-min-rx-interval> + </session-group> + </session-groups> + </mpls> + </bfd> + </control-plane-protocol> + </control-plane-protocols> + </routing> + </config> + +4. Security Considerations + + The YANG modules specified in this document define a schema for data + that is designed to be accessed via network management protocols such + as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer + is the secure transport layer, and the mandatory-to-implement secure + transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer + is HTTPS, and the mandatory-to-implement secure transport is TLS + [RFC8446]. + + The Network Configuration Access Control Model (NACM) [RFC8341] + provides the means to restrict access for particular NETCONF or + RESTCONF users to a preconfigured subset of all available NETCONF or + RESTCONF protocol operations and content. + + There are a number of data nodes defined in these YANG modules that + are writable/creatable/deletable (i.e., config true, which is the + default). These data nodes may be considered sensitive or vulnerable + in some network environments. Write operations (e.g., edit-config) + to these data nodes without proper protection can have a negative + effect on network operations. These are the subtrees and data nodes + and their sensitivity/vulnerability from a write access perspective: + + /routing/control-plane-protocols/control-plane-protocol/bfd/ip-sh/ + sessions: + This list specifies the IP single-hop BFD sessions. + + Data nodes "local-multiplier", "desired-min-tx-interval", + "required-min-rx-interval", and "min-interval" all impact the BFD + IP single-hop session. The "source-addr" and "dest-addr" data + nodes can be used to send BFD packets to unwitting recipients. + [RFC5880] describes how BFD mitigates such threats. + Authentication data nodes "key-chain" and "meticulous" impact the + security of the BFD IP single-hop session. + + /routing/control-plane-protocols/control-plane-protocol/bfd/ip-mh/ + session-group: + This list specifies the IP multihop BFD session groups. + + Data nodes "local-multiplier", "desired-min-tx-interval", + "required-min-rx-interval", and "min-interval" all impact the BFD + IP multihop session. The "source-addr" and "dest-addr" data nodes + can be used to send BFD packets to unwitting recipients. + [RFC5880] describes how BFD mitigates such threats. + Authentication data nodes "key-chain" and "meticulous" impact the + security of the BFD IP multihop session. + + /routing/control-plane-protocols/control-plane-protocol/bfd/lag/ + sessions: + This list specifies the BFD sessions over a LAG. + + Data nodes "local-multiplier", "desired-min-tx-interval", + "required-min-rx-interval", and "min-interval" all impact the BFD- + over-LAG session. The "ipv4-dest-addr" and "ipv6-dest-addr" data + nodes can be used to send BFD packets to unwitting recipients. + [RFC5880] describes how BFD mitigates such threats. + Authentication data nodes "key-chain" and "meticulous" impact the + security of the BFD-over-LAG session. + + /routing/control-plane-protocols/control-plane-protocol/bfd/mpls/ + session-group: + This list specifies the session groups for BFD over MPLS. + + Data nodes "local-multiplier", "desired-min-tx-interval", + "required-min-rx-interval", and "min-interval" all impact the BFD- + over-MPLS-LSPs session. Authentication data nodes "key-chain" and + "meticulous" impact the security of the BFD-over-MPLS-LSPs + session. + + /routing/control-plane-protocols/control-plane-protocol/bfd/mpls/ + egress: + Data nodes "local-multiplier", "desired-min-tx-interval", + "required-min-rx-interval", and "min-interval" all impact the BFD- + over-MPLS-LSPs sessions for which this device is an MPLS LSP + egress node. Authentication data nodes "key-chain" and + "meticulous" impact the security of the BFD-over-MPLS-LSPs + sessions for which this device is an MPLS LSP egress node. + + The YANG modules have writable data nodes that can be used for the + creation of BFD sessions and the modification of BFD session + parameters. The system should "police" the creation of BFD sessions + to prevent new sessions from causing existing BFD sessions to fail. + In the case of BFD session modification, the BFD protocol has + mechanisms in place that allow for in-service modification. + + When BFD clients are used to modify BFD configuration (as described + in Section 2.1), the BFD clients need to be included in an analysis + of the security properties of the system that uses BFD (e.g., when + considering the authentication and authorization of control actions). + In many cases, BFD is not the most vulnerable portion of such a + composite system, since BFD is limited to generating well-defined + traffic at a fixed rate on a given path; in the case of an IGP acting + as a BFD client, attacking the IGP could cause more broad-scale + disruption than would (de)configuring a BFD session. + + Some of the readable data nodes in these YANG modules may be + considered sensitive or vulnerable in some network environments. It + is thus important to control read access (e.g., via get, get-config, + or notification) to these data nodes. These are the subtrees and + data nodes and their sensitivity/vulnerability from a read access + perspective: + + /routing/control-plane-protocols/control-plane-protocol/bfd/ip-sh/ + summary: + Access to this information discloses the number of BFD IP single- + hop sessions that are in the "up", "down", or "admin-down" state. + The counters include BFD sessions for which the user does not have + read access. + + /routing/control-plane-protocols/control-plane-protocol/bfd/ip- + sh/sessions/session/: + Access to data nodes "local-discriminator" and "remote- + discriminator" (combined with the data nodes in the authentication + container) provides the ability to spoof BFD IP single-hop + packets. + + /routing/control-plane-protocols/control-plane-protocol/bfd/ip-mh/ + summary: + Access to this information discloses the number of BFD IP multihop + sessions that are in the "up", "down", or "admin-down" state. The + counters include BFD sessions for which the user does not have + read access. + + /routing/control-plane-protocols/control-plane-protocol/bfd/ip-mh/ + session-groups/session-group/sessions: + Access to data nodes "local-discriminator" and "remote- + discriminator" (combined with the data nodes in the session + group's authentication container) provides the ability to spoof + BFD IP multihop packets. + + /routing/control-plane-protocols/control-plane-protocol/bfd/lag/ + micro-bfd-ipv4-session-statistics/summary: + Access to this information discloses the number of micro-BFD IPv4 + LAG sessions that are in the "up", "down", or "admin-down" state. + The counters include BFD sessions for which the user does not have + read access. + + /routing/control-plane-protocols/control-plane- + protocol/bfd/lag/sessions/session/member-links/member-link/micro- + bfd-ipv4: + Access to data nodes "local-discriminator" and "remote- + discriminator" (combined with the data nodes in the session's + authentication container) provides the ability to spoof BFD IPv4 + LAG packets. + + /routing/control-plane-protocols/control-plane-protocol/bfd/lag/ + micro-bfd-ipv6-session-statistics/summary: + Access to this information discloses the number of micro-BFD IPv6 + LAG sessions that are in the "up", "down", or "admin-down" state. + The counters include BFD sessions for which the user does not have + read access. + + /routing/control-plane-protocols/control-plane- + protocol/bfd/lag/sessions/session/member-links/member-link/micro- + bfd-ipv6: + Access to data nodes "local-discriminator" and "remote- + discriminator" (combined with the data nodes in the session's + authentication container) provides the ability to spoof BFD IPv6 + LAG packets. + + /routing/control-plane-protocols/control-plane-protocol/bfd/mpls/ + summary: + Access to this information discloses the number of BFD sessions + over MPLS LSPs that are in the "up", "down", or "admin-down" + state. The counters include BFD sessions for which the user does + not have read access. + + /routing/control-plane-protocols/control-plane-protocol/bfd/mpls/ + session-groups/session-group/sessions: + Access to data nodes "local-discriminator" and "remote- + discriminator" (combined with the data nodes in the session + group's authentication container) provides the ability to spoof + BFD-over-MPLS-LSPs packets. + + This document does not define any RPC operations. + +5. IANA Considerations + + IANA has registered the following namespace URIs in the "IETF XML + Registry" [RFC3688]: + + URI: urn:ietf:params:xml:ns:yang:iana-bfd-types + Registrant Contact: The IESG. + XML: N/A; the requested URI is an XML namespace. + + URI: urn:ietf:params:xml:ns:yang:ietf-bfd-types + Registrant Contact: The IESG. + XML: N/A; the requested URI is an XML namespace. + + URI: urn:ietf:params:xml:ns:yang:ietf-bfd + Registrant Contact: The IESG. + XML: N/A; the requested URI is an XML namespace. + + URI: urn:ietf:params:xml:ns:yang:ietf-bfd-ip-sh + Registrant Contact: The IESG. + XML: N/A; the requested URI is an XML namespace. + + URI: urn:ietf:params:xml:ns:yang:ietf-bfd-ip-mh + Registrant Contact: The IESG. + XML: N/A; the requested URI is an XML namespace. + + URI: urn:ietf:params:xml:ns:yang:ietf-bfd-lag + Registrant Contact: The IESG. + XML: N/A; the requested URI is an XML namespace. + + URI: urn:ietf:params:xml:ns:yang:ietf-bfd-mpls + Registrant Contact: The IESG. + XML: N/A; the requested URI is an XML namespace. + + IANA has registered the following YANG modules in the "YANG Module + Names" registry [RFC6020]: + + Name: iana-bfd-types + Namespace: urn:ietf:params:xml:ns:yang:iana-bfd-types + Prefix: iana-bfd-types + Reference: RFC 9127 + + Name: ietf-bfd-types + Namespace: urn:ietf:params:xml:ns:yang:ietf-bfd-types + Prefix: bfd-types + Reference: RFC 9127 + + Name: ietf-bfd + Namespace: urn:ietf:params:xml:ns:yang:ietf-bfd + Prefix: bfd + Reference: RFC 9127 + + Name: ietf-bfd-ip-sh + Namespace: urn:ietf:params:xml:ns:yang:ietf-bfd-ip-sh + Prefix: bfd-ip-sh + Reference: RFC 9127 + + Name: ietf-bfd-ip-mh + Namespace: urn:ietf:params:xml:ns:yang:ietf-bfd-ip-mh + Prefix: bfd-ip-mh + Reference: RFC 9127 + + Name: ietf-bfd-lag + Namespace: urn:ietf:params:xml:ns:yang:ietf-bfd-lag + Prefix: bfd-lag + Reference: RFC 9127 + + Name: ietf-bfd-mpls + Namespace: urn:ietf:params:xml:ns:yang:ietf-bfd-mpls + Prefix: bfd-mpls + Reference: RFC 9127 + +5.1. IANA-Maintained "iana-bfd-types" Module + + This document defines the initial version of the IANA-maintained + "iana-bfd-types" YANG module. + + The "iana-bfd-types" YANG module mirrors the "BFD Diagnostic Codes" + and "BFD Authentication Types" registries at + <https://www.iana.org/assignments/bfd-parameters/>. Whenever these + registries change, IANA must update the "iana-bfd-types" YANG module. + +6. References + +6.1. Normative References + + [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, + DOI 10.17487/RFC3688, January 2004, + <https://www.rfc-editor.org/info/rfc3688>. + + [RFC5586] Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed., + "MPLS Generic Associated Channel", RFC 5586, + DOI 10.17487/RFC5586, June 2009, + <https://www.rfc-editor.org/info/rfc5586>. + + [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection + (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, + <https://www.rfc-editor.org/info/rfc5880>. + + [RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection + (BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881, + DOI 10.17487/RFC5881, June 2010, + <https://www.rfc-editor.org/info/rfc5881>. + + [RFC5882] Katz, D. and D. Ward, "Generic Application of + Bidirectional Forwarding Detection (BFD)", RFC 5882, + DOI 10.17487/RFC5882, June 2010, + <https://www.rfc-editor.org/info/rfc5882>. + + [RFC5883] Katz, D. and D. Ward, "Bidirectional Forwarding Detection + (BFD) for Multihop Paths", RFC 5883, DOI 10.17487/RFC5883, + June 2010, <https://www.rfc-editor.org/info/rfc5883>. + + [RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, + "Bidirectional Forwarding Detection (BFD) for MPLS Label + Switched Paths (LSPs)", RFC 5884, DOI 10.17487/RFC5884, + June 2010, <https://www.rfc-editor.org/info/rfc5884>. + + [RFC5885] Nadeau, T., Ed. and C. Pignataro, Ed., "Bidirectional + Forwarding Detection (BFD) for the Pseudowire Virtual + Circuit Connectivity Verification (VCCV)", RFC 5885, + DOI 10.17487/RFC5885, June 2010, + <https://www.rfc-editor.org/info/rfc5885>. + + [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for + the Network Configuration Protocol (NETCONF)", RFC 6020, + DOI 10.17487/RFC6020, October 2010, + <https://www.rfc-editor.org/info/rfc6020>. + + [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., + and A. Bierman, Ed., "Network Configuration Protocol + (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, + <https://www.rfc-editor.org/info/rfc6241>. + + [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure + Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, + <https://www.rfc-editor.org/info/rfc6242>. + + [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", + RFC 6991, DOI 10.17487/RFC6991, July 2013, + <https://www.rfc-editor.org/info/rfc6991>. + + [RFC7130] Bhatia, M., Ed., Chen, M., Ed., Boutros, S., Ed., + Binderberger, M., Ed., and J. Haas, Ed., "Bidirectional + Forwarding Detection (BFD) on Link Aggregation Group (LAG) + Interfaces", RFC 7130, DOI 10.17487/RFC7130, February + 2014, <https://www.rfc-editor.org/info/rfc7130>. + + [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF + Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, + <https://www.rfc-editor.org/info/rfc8040>. + + [RFC8177] Lindem, A., Ed., Qu, Y., Yeung, D., Chen, I., and J. + Zhang, "YANG Data Model for Key Chains", RFC 8177, + DOI 10.17487/RFC8177, June 2017, + <https://www.rfc-editor.org/info/rfc8177>. + + [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", + BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, + <https://www.rfc-editor.org/info/rfc8340>. + + [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration + Access Control Model", STD 91, RFC 8341, + DOI 10.17487/RFC8341, March 2018, + <https://www.rfc-editor.org/info/rfc8341>. + + [RFC8343] Bjorklund, M., "A YANG Data Model for Interface + Management", RFC 8343, DOI 10.17487/RFC8343, March 2018, + <https://www.rfc-editor.org/info/rfc8343>. + + [RFC8344] Bjorklund, M., "A YANG Data Model for IP Management", + RFC 8344, DOI 10.17487/RFC8344, March 2018, + <https://www.rfc-editor.org/info/rfc8344>. + + [RFC8349] Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for + Routing Management (NMDA Version)", RFC 8349, + DOI 10.17487/RFC8349, March 2018, + <https://www.rfc-editor.org/info/rfc8349>. + + [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol + Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, + <https://www.rfc-editor.org/info/rfc8446>. + + [RFC8960] Saad, T., Raza, K., Gandhi, R., Liu, X., and V. Beeram, "A + YANG Data Model for MPLS Base", RFC 8960, + DOI 10.17487/RFC8960, December 2020, + <https://www.rfc-editor.org/info/rfc8960>. + +6.2. Informative References + + [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol + Label Switching Architecture", RFC 3031, + DOI 10.17487/RFC3031, January 2001, + <https://www.rfc-editor.org/info/rfc3031>. + + [RFC6428] Allan, D., Ed., Swallow, G., Ed., and J. Drake, Ed., + "Proactive Connectivity Verification, Continuity Check, + and Remote Defect Indication for the MPLS Transport + Profile", RFC 6428, DOI 10.17487/RFC6428, November 2011, + <https://www.rfc-editor.org/info/rfc6428>. + + [RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., + and R. Wilton, "Network Management Datastore Architecture + (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018, + <https://www.rfc-editor.org/info/rfc8342>. + + [RFC8529] Berger, L., Hopps, C., Lindem, A., Bogdanovic, D., and X. + Liu, "YANG Data Model for Network Instances", RFC 8529, + DOI 10.17487/RFC8529, March 2019, + <https://www.rfc-editor.org/info/rfc8529>. + + [RFC8530] Berger, L., Hopps, C., Lindem, A., Bogdanovic, D., and X. + Liu, "YANG Model for Logical Network Elements", RFC 8530, + DOI 10.17487/RFC8530, March 2019, + <https://www.rfc-editor.org/info/rfc8530>. + + [RFC8532] Kumar, D., Wang, Z., Wu, Q., Ed., Rahman, R., and S. + Raghavan, "Generic YANG Data Model for the Management of + Operations, Administration, and Maintenance (OAM) + Protocols That Use Connectionless Communications", + RFC 8532, DOI 10.17487/RFC8532, April 2019, + <https://www.rfc-editor.org/info/rfc8532>. + + [W3C.REC-xml-20081126] + Bray, T., Paoli, J., Sperberg-McQueen, M., Maler, E., and + F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth + Edition)", World Wide Web Consortium Recommendation REC- + xml-20081126, November 2008, + <https://www.w3.org/TR/2008/REC-xml-20081126>. + +Appendix A. Echo Function Configuration Example + + As mentioned in Section 2.1.2, the mechanism to start and stop the + Echo function, as defined in [RFC5880] and discussed in [RFC5881], is + implementation specific. In this appendix, we provide an example of + how the Echo function can be implemented via configuration. + + module: example-bfd-echo + augment /rt:routing/rt:control-plane-protocols + /rt:control-plane-protocol/bfd:bfd/bfd-ip-sh:ip-sh + /bfd-ip-sh:sessions: + +--rw echo {bfd-types:echo-mode}? + +--rw desired-min-echo-tx-interval? uint32 + +--rw required-min-echo-rx-interval? uint32 + +A.1. Example YANG Module for BFD Echo Function Configuration + + This appendix provides an example YANG module for configuration of + the BFD Echo function. It imports and augments "/routing/control- + plane-protocols/control-plane-protocol" from [RFC8349], and it + references [RFC5880]. + + module example-bfd-echo { + namespace "tag:example.com,2021:example-bfd-echo"; + prefix example-bfd-echo; + + import ietf-bfd-types { + prefix bfd-types; + } + import ietf-bfd { + prefix bfd; + } + import ietf-bfd-ip-sh { + prefix bfd-ip-sh; + } + import ietf-routing { + prefix rt; + } + + organization + "IETF BFD Working Group"; + contact + "WG Web: <https://datatracker.ietf.org/wg/bfd/> + WG List: <mailto:rtg-bfd@ietf.org> + + Editor: Reshad Rahman + <mailto:reshad@yahoo.com> + + Editor: Lianshu Zheng + <mailto:veronique_cheng@hotmail.com> + + Editor: Mahesh Jethanandani + <mailto:mjethanandani@gmail.com>"; + description + "This module contains an example YANG augmentation for + configuration of the BFD Echo function. + + Copyright (c) 2021 IETF Trust and the persons identified as + authors of the code. All rights reserved. + + Redistribution and use in source and binary forms, with or + without modification, is permitted pursuant to, and subject to + the license terms contained in, the Simplified BSD License set + forth in Section 4.c of the IETF Trust's Legal Provisions + Relating to IETF Documents + (https://trustee.ietf.org/license-info). + + This version of this YANG module is part of RFC 9127; see the + RFC itself for full legal notices."; + + revision 2021-09-03 { + description + "Initial revision."; + reference + "RFC 9127: YANG Data Model for Bidirectional Forwarding + Detection (BFD)"; + } + + /* + * Groupings + */ + + grouping echo-cfg-parms { + description + "BFD grouping for Echo configuration parameters."; + leaf desired-min-echo-tx-interval { + type uint32; + units "microseconds"; + default "0"; + description + "This is the minimum interval that the local system would + like to use when transmitting BFD Echo packets. If 0, + the Echo function as defined in BFD (RFC 5880) is + disabled."; + } + leaf required-min-echo-rx-interval { + type uint32; + units "microseconds"; + default "0"; + description + "This is the Required Min Echo RX Interval as defined in BFD + (RFC 5880)."; + } + } + + augment "/rt:routing/rt:control-plane-protocols/" + + "rt:control-plane-protocol/bfd:bfd/bfd-ip-sh:ip-sh/" + + "bfd-ip-sh:sessions" { + description + "Augmentation for the BFD Echo function."; + container echo { + if-feature "bfd-types:echo-mode"; + description + "BFD Echo function container."; + uses echo-cfg-parms; + } + } + } + +Acknowledgments + + We would like to thank Nobo Akiya and Jeff Haas for their + encouragement on this work. We would also like to thank Tom Petch + for his comments on the document. We would also like to thank Acee + Lindem for his guidance. Thanks also to Jürgen Schönwälder, who was + instrumental in improving the YANG modules. + +Authors' Addresses + + Reshad Rahman (editor) + Canada + + Email: reshad@yahoo.com + + + Lianshu Zheng (editor) + Huawei Technologies + China + + Email: veronique_cheng@hotmail.com + + + Mahesh Jethanandani (editor) + Xoriant Corporation + 1248 Reamwood Ave + Sunnyvale, California 94089 + United States of America + + Email: mjethanandani@gmail.com + + + Santosh Pallagatti + VMware + India + + Email: santosh.pallagatti@gmail.com + + + Greg Mirsky + Ericsson + + Email: gregimirsky@gmail.com |