diff options
| author | Thomas Voss <mail@thomasvoss.com> | 2024-11-27 20:54:24 +0100 |
|---|---|---|
| committer | Thomas Voss <mail@thomasvoss.com> | 2024-11-27 20:54:24 +0100 |
| commit | 4bfd864f10b68b71482b35c818559068ef8d5797 (patch) | |
| tree | e3989f47a7994642eb325063d46e8f08ffa681dc /doc/rfc/rfc6329.txt | |
| parent | ea76e11061bda059ae9f9ad130a9895cc85607db (diff) | |
doc: Add RFC documents
Diffstat (limited to 'doc/rfc/rfc6329.txt')
| -rw-r--r-- | doc/rfc/rfc6329.txt | 2075 |
1 files changed, 2075 insertions, 0 deletions
diff --git a/doc/rfc/rfc6329.txt b/doc/rfc/rfc6329.txt new file mode 100644 index 0000000..7fc4ba8 --- /dev/null +++ b/doc/rfc/rfc6329.txt @@ -0,0 +1,2075 @@ + + + + + + +Internet Engineering Task Force (IETF) D. Fedyk, Ed. +Request for Comments: 6329 Alcatel-Lucent +Category: Standards Track P. Ashwood-Smith, Ed. +ISSN: 2070-1721 Huawei + D. Allan + Ericsson + N. Bragg + Ciena Limited + P. Unbehagen + Avaya + April 2012 + + + IS-IS Extensions Supporting IEEE 802.1aq Shortest Path Bridging + +Abstract + + 802.1aq Shortest Path Bridging (SPB) has been standardized by the + IEEE as the next step in the evolution of the various spanning tree + and registration protocols. 802.1aq allows for true shortest path + forwarding in a mesh Ethernet network context utilizing multiple + equal cost paths. This permits it to support much larger Layer 2 + topologies, with faster convergence, and vastly improved use of the + mesh topology. Combined with this is single point provisioning for + logical connectivity membership, which includes point-to-point, + point-to-multipoint, and multipoint-to-multipoint variations. This + memo documents the IS-IS changes required to support this IEEE + protocol and provides some context and examples. + +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 5741. + + Information about the current status of this document, any errata, + and how to provide feedback on it may be obtained at + http://www.rfc-editor.org/info/rfc6329. + + + + + + + + + +Fedyk, et al. Standards Track [Page 1] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + +Copyright Notice + + Copyright (c) 2012 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 + (http://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. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Fedyk, et al. Standards Track [Page 2] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + +Table of Contents + + 1. Introduction ....................................................4 + 2. Terminology .....................................................4 + 3. Conventions Used in This Document ...............................5 + 4. 802.1aq Overview ................................................6 + 4.1. Multi-Topology Support .....................................8 + 4.2. Data Path SPBM - Unicast ...................................8 + 4.3. Data Path SPBM - Multicast (Head-End Replication) ..........9 + 4.4. Data Path SPBM - Multicast (Tandem Replication) ............9 + 4.5. Data Path SPBV Broadcast ..................................11 + 4.6. Data Path SPBV Unicast ....................................11 + 4.7. Data Path SPBV Multicast ..................................12 + 5. SPBM Example ...................................................12 + 6. SPBV Example ...................................................14 + 7. SPB Supported Adjacency types ..................................16 + 8. SPB IS-IS Adjacency Addressing .................................16 + 9. IS-IS Area Address and SYSID ...................................17 + 10. Level 1/2 Adjacency ...........................................17 + 11. Shortest Path Default Tie-Breaking ............................17 + 12. Shortest Path ECT .............................................18 + 13. Hello (IIH) Protocol Extensions ...............................19 + 13.1. SPB-MCID Sub-TLV .........................................20 + 13.2. SPB-Digest Sub-TLV .......................................21 + 13.3. SPB Base VLAN Identifiers (SPB-B-VID) Sub-TLV ............23 + 14. Node Information Extensions ...................................24 + 14.1. SPB Instance (SPB-Inst) Sub-TLV ..........................24 + 14.1.1. SPB Instance Opaque ECT-ALGORITHM + (SPB-I-OALG) Sub-TLV ..............................28 + 15. Adjacency Information Extensions ..............................29 + 15.1. SPB Link Metric (SPB-Metric) Sub-TLV .....................29 + 15.1.1. SPB Adjacency Opaque ECT-ALGORITHM + (SPB-A-OALG) Sub-TLV ..............................30 + 16. Service Information Extensions ................................30 + 16.1. SPBM Service Identifier and Unicast Address + (SPBM-SI) Sub-TLV ........................................30 + 16.2. SPBV MAC Address (SPBV-ADDR) Sub-TLV .....................32 + 17. Security Considerations .......................................34 + 18. IANA Considerations ...........................................34 + 19. References ....................................................35 + 19.1. Normative References .....................................35 + 19.2. Informative References ...................................36 + 20. Acknowledgments ...............................................36 + + + + + + + + +Fedyk, et al. Standards Track [Page 3] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + +1. Introduction + + 802.1aq Shortest Path Bridging (SPB) [802.1aq] has been standardized + by the IEEE as the next step in the evolution of the various spanning + tree and registration protocols. 802.1aq allows for true shortest + path forwarding in an Ethernet mesh network context utilizing + multiple equal cost paths. This permits SPB to support much larger + Layer 2 topologies, with faster convergence, and vastly improved use + of the mesh topology. Combined with this is single point + provisioning for logical connectivity membership, which includes + point-to-point (E-LINE), point-to-multipoint (E-TREE), and + multipoint-to-multipoint (E-LAN) variations. + + The control protocol for 802.1aq is IS-IS [IS-IS] augmented with a + small number of TLVs and sub-TLVs. This supports two Ethernet + encapsulating data paths, 802.1ad (Provider Bridges) [PB] and 802.1ah + (Provider Backbone Bridges) [PBB]. This memo documents those TLVs + while providing some overview. + + Note that 802.1aq requires no state machine or other substantive + changes to [IS-IS]. 802.1aq simply requires a new Network Layer + Protocol Identifier (NLPID) and set of TLVs. In the event of + confusion between this document and [IS-IS], [IS-IS] should be taken + as authoritative. + +2. Terminology + + In addition to well-understood IS-IS terms, this memo uses + terminology from IEEE 802.1 and introduces a few terms: + + 802.1ad Provider Bridges (PBs) - Q-in-Q encapsulation + 802.1ah Provider Backbone Bridges (PBBs), MAC-IN-MAC + encapsulation + 802.1aq Shortest Path Bridging (SPB) + Base VID VID used to identify a VLAN in management operations + B-DA Backbone Destination Address 802.1ah PBB + B-MAC Backbone MAC Address + B-SA Backbone Source Address in 802.1ah PBB header + B-VID Backbone VLAN ID in 802.1ah PBB header + B-VLAN Backbone Virtual LAN + BPDU Bridge PDU + BridgeID 64-bit quantity = (Bridge Priority:16)<<48 | SYSID:48 + BridgePriority 16-bit relative priority of a node for tie-breaking + C-MAC Customer MAC. Inner MAC in 802.1ah PBB header + C-VID Customer VLAN ID + ECT-ALGORITHM 32-bit unique ID of an SPF tie-breaking set of rules + ECT-MASK 64-bit mask XORed with BridgeID during tie-breaking + E-LAN Bidirectional Logical Connectivity between >2 UNIs + + + +Fedyk, et al. Standards Track [Page 4] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + E-LINE Bidirectional Logical Connectivity between two UNIs + E-TREE Asymmetric Logical Connectivity between UNIs + FDB Filtering Database: {DA/VID}->{next hops} + I-SID Ethernet Services Instance Identifier used for + Logical Grouping for E-LAN/LINE/TREE UNIs + LAN Local Area Network + LSDB Link State Database + LSP Link State PDU + MAC Media Access Control + MAC-IN-MAC Ethernet in Ethernet framing as per 802.1ah [PBB] + MDT Multicast Distribution Tree + MMRP Multiple MAC Registration Protocol 802.1ak [MMRP] + MT Multi-Topology. As used in [MT] + MT ID Multi-Topology Identifier (12 bits). As used in [MT] + NLPID Network Layer Protocol Identifier: IEEE 802.1aq= 0xC1 + NNI Network-Network Interface + Q-in-Q Additional S-VID after a C-VID (802.1ad) [PB] + PBB Provider Backbone Bridge - forwards using PBB + Ingress Check Source Forwarding Check - drops misdirected frames + (S,G) Source & Group - identity of a source-specific tree + (*,G) Any Source & Group - identity of a shared tree + S-VID Service VLAN ID + SA Source Address + SPB Shortest Path Bridging - generally all of 802.1aq + SPB Shortest Path Bridge - device implementing 802.1aq + SPB-instance Logical SPB instance correlated by MT ID + SPBM Device implementing SPB MAC mode + SPBV Device implementing SPB VID mode + SPSourceID 20-bit identifier of the source of multicast frames + SPT Shortest Path Tree computed by one ECT-ALGORITHM + SPT Region A set of SPBs with identical VID usage on their NNIs + SPVID Shortest Path VLAN ID: a C-VID or S-VID that + identifies the source + STP Spanning Tree Protocol + UNI User-Network Interface: customer-to-SPB attach point + VID VLAN ID: 12-bit logical identifier after MAC header + VLAN Virtual LAN: a logical network in the control plane + +3. Conventions Used in This Document + + The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", + "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this + document are to be interpreted as described in [RFC2119]. + + The lowercase forms with an initial capital "Must", "Must Not", + "Shall", "Shall Not", "Should", "Should Not", "May", and "Optional" + in this document are to be interpreted in the sense defined in + + + + +Fedyk, et al. Standards Track [Page 5] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + [RFC2119], but are used where the normative behavior is defined in + documents published by SDOs other than the IETF. + +4. 802.1aq Overview + + This section provides an overview of the behavior of [802.1aq] and is + not intended to be interpreted as normative text. For the definitive + behavior, the reader should consult [802.1aq]. Nonetheless, + lowercase forms with initial capitalization of the conventions in RFC + 2119 are used in this section to give the reader an indication of the + intended normative behaviors as above. + + 802.1aq utilizes 802.1Q-based Ethernet bridging. The filtering + database (FDB) is populated as a consequence of the topology computed + from the IS-IS database. For the reader unfamiliar with IEEE + terminology, the definition of Ethernet behavior is almost entirely + in terms of "filtering" (of broadcast traffic) rather than + "forwarding" (the explicit direction of unicast traffic). This + document uses the generic term "forwarding", and it has to be + understood that these two terms simply represent different ways of + expressing the same behaviors. + + 802.1aq supports multiple modes of operation depending on the type of + data plane and the desired behavior. For the initial two modes of + 802.1aq (SPBV and SPBM), routes are shortest path, are forward- and + reverse-path symmetric with respect to any source/destination pair + within the SPB domain, and are congruent with respect to unicast and + multicast. Hence, the shortest path tree (SPT) to a given node is + congruent with the multicast distribution tree (MDT) from a given + node. The MDT for a given VLAN is a pruned subset of the complete + MDT for a given node that is identical to its SPT. Symmetry and + congruency preserve packet ordering and proper fate sharing of + Operations, Administration, and Maintenance (OAM) flows by the + forwarding path. Such modes are fully supported by existing + [802.1ag] and [Y.1731] OAM mechanisms. + + VLANs provide a natural delineation of service instances. 802.1aq + supports two modes, SPB VID (SPBV) and SPB MAC (SPBM). In SPBV, + multiple VLANS can be used to distribute load on different shortest + path trees (each computed by a different tie-breaking rule) on a + service basis. In SPBM, service instances are delineated by I-SIDs + but VLANs again can be used to distribute load on different shortest + path trees. + + There are two encapsulation methods supported. SPBM can be used in a + PBB network implementing PBB (802.1ah [PBB]) encapsulation. SPBV can + be used in PB networks implementing VLANs, PB (802.1aq [PB]), or PBB + + + + +Fedyk, et al. Standards Track [Page 6] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + encapsulation. The two modes can co-exist simultaneously in an SPB + network. + + The practical design goals for SPBV and SPBM in the current 802.1aq + specification are networks of size 100 nodes and 1000 nodes + respectively. However, since SPBV can be sparsely used in an SPB + region it can simply span a large SPB region with a small number of + SPVIDs. + + In SPBM and SPBV each bridge has at least one unique "known" MAC + address which is advertised by IS-IS in the SYSID. + + In the forwarding plane, SPBM uses the combination of one or more + B-VIDs and "known" Backbone-MAC (B-MAC) addresses that have been + advertised in IS-IS. The term Backbone simply implies an + encapsulation that is often used in the backbone networks, but the + encapsulation is useful in other types of networks where hiding + C-MACs is useful. + + The SPBM filtering database (FDB) is computed and installed for + unicast and multicast MAC addresses, while the SPBV filtering + database is computed and installed for unidirectional VIDs (referred + to as SPVIDs), after which MAC reachability is learned (exactly as in + bridged Ethernet) for unicast MACs. + + Both SPBV and SPBM use source-specific multicast trees. If they + share the same ECT-ALGORITHM (32-bit worldwide unique definition of + the computation), the tree is the same SPT. For SPBV, (S,G) is + encoded by a source-specific VID (the SPVID) and a standard Group MAC + address. For SPBM, (S,G) is encoded in the destination B-MAC address + as the concatenation of a 20-bit SPB wide unique nodal nickname + (referred to as the SPSourceID) and the 24-bit I-SID together with + the B-VID that corresponds to the ECT-ALGORITHM network wide. + + 802.1aq supports membership attributes that are advertised with the + I-SID (SPBM) or Group Address (SPBV) that defines the group. + Individual members can be transmitters (T) and/or receivers (R) + within the group, and the multicast state is appropriately sized to + these requests. Multicast group membership is possible even without + transmit membership by performing head-end replication to the + receivers thereby eliminating transit multicast state entirely. + + Some highly connected mesh networks provide for path diversity by + offering multiple equal cost alternatives between nodes. Since + congruency and symmetry Must be honored, a single tree may leave some + links under-utilized. By using different deterministic tie-breakers, + up to 16 shortest paths of arbitrary diversity are possible between + any pair of nodes. This distributes the traffic on a VLAN basis. + + + +Fedyk, et al. Standards Track [Page 7] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + SPBV and SPBM May share a single SPT with a single ECT-ALGORITHM or + use any combination of the 16 ECT-ALGORITHMs. An extensible + framework permits additional or alternative algorithms with other + properties and parameters (e.g., ECMP, (*,G)) to also be supported + without any changes in this or the IEEE documents. + +4.1. Multi-Topology Support + + SPB incorporates the multi topology features of [MT] thereby allowing + multiple logical SPB instances within a single IS-IS instance. + + To accomplish this, all SPB-related information is either explicitly + or implicitly associated with a Multi-Topology Identifier (MT ID). + SPB information related to a given MT ID thus forms a single logical + SPB instance. + + Since SPB has its own adjacency metrics and those metrics are also + associated with an MT ID, it is possible to have different adjacency + metrics (or infinite metrics) for SPB adjacencies that are not only + distinct from IP or other NLPIDs riding in this IS-IS instance, but + also distinct from those used by other SPB instances in the same + IS-IS instance. + + Data plane traffic for a given MT ID is intrinsically isolated by the + VLANs assigned to the SPB instance in question. Therefore, VLANs + (represented by VIDs in TLVs and in the data plane) Must Not overlap + between SPB instances (regardless of how the control planes are + isolated). + + The [MT] mechanism when applied to SPB allows different routing + metrics and topology subsets for different classes of services. + + The use of [MT] other than the default MT ID #0 is completely + OPTIONAL. + + The use of [MT] to separate SPB from other NLPIDs is also OPTIONAL. + +4.2. Data Path SPBM - Unicast + + Unicast frames in SPBM are encapsulated as per 802.1ah [PBB]. A + Backbone Source Address (B-SA), Backbone Destination Address (B-DA), + Backbone VLAN ID (B-VID), and an I-Component Service Instance ID + (I-TAG) are used to encapsulate the Ethernet frame. The B-SA is a + B-MAC associated with the ingress 802.1aq bridge, usually the "known" + B-MAC of that entire bridge. The B-DA is one of the "known" B-MACs + associated with the egress 802.1aq bridge. The B-VID and I-TAG are + mapped based on the physical or logical UNI port (untagged, or tagged + either by S-TAG or C-TAG) being bridged. Normal learning and + + + +Fedyk, et al. Standards Track [Page 8] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + broadcast to unknown C-MACs is applied as per [PBB] at the + ingress/egress SPBs only. + + Unlike [PBB] on a (*,G) tree, the B-DA forwarding on tandem nodes + (NNI to NNI) is performed without learning. Instead, the output of + 802.1aq computations, based on the TLVs specified in this document, + is used to populate the filtering databases (FDBs). The FDB entries + map {B-DA, B-VID} to an outgoing interface and are only populated + from the IS-IS database and computations. + + The B-SA/B-VID is checked on tandem nodes against the ingress port. + If the B-SA/B-VID (as a destination) entry in the FDB does not point + to the port on which the packet arrived, the packet is discarded. + This is referred to as an ingress check and serves as a very powerful + loop mitigation mechanism. + +4.3. Data Path SPBM - Multicast (Head-End Replication) + + Head-end replication is supported for instances where there is a + sparse community of interest or a low likelihood of multicast + traffic. Head-end replication requires no multicast state in the + core. A UNI port wishing to use head-end replication Must Not + advertise its I-SID membership with the Transmit (T) bit set but + instead Must locally and dynamically construct the appropriate + unicast serial replication to all the other receivers (Receive (R) + bit set) of the same I-SID. + + When an unknown customer unicast or a multicast frame arrives at an + SPBM User-Network Interface (UNI) port that has been configured to + replicate only at the head end, the packet is replicated once for + each receiver, encapsulated, and sent as a unicast frame. The set of + receivers is determined by inspecting the IS-IS database for other + SPBs that have registered interest in the same I-SID with the R bit + set. This R bit / I-SID pair is found in the SPBM Service Identifier + and Unicast Address (SPBM-SI) sub-TLV. The packets are encapsulated + as per the SPBM unicast forwarding above. + +4.4. Data Path SPBM - Multicast (Tandem Replication) + + Tandem replication uses the shortest path tree to replicate frames + only where the tree forks and there is at least one receiver on each + branch. Tandem replication is bandwidth efficient but uses multicast + FDB entries (state) in core bridges, which might be unnecessary if + there is little multicast traffic demand. The head-end replication + mode is best suited for the case where there is little or no true + multicast traffic for an I-SID. Tandem replication is triggered on + transit nodes when the I-SID is advertised with the T bit set. + + + + +Fedyk, et al. Standards Track [Page 9] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + Broadcast, unknown unicast, or multicast frames arriving at an SPBM + UNI port are encapsulated with a B-DA multicast address that uniquely + identifies the encapsulating node (the root of the Multicast + Distribution Tree) and the I-SID scoping this multicast. + + This B-DA address is a well-formed multicast group address (as per + 802.1Q and 802.1ah) that concatenates the SPSourceID A' with the + I-SID M (written as DA=<A',M> and uniquely identifying the (S,G) + tree). This exact format is given in Figure 1 below: + + M L TYP + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |1|1|0|0|SPSrcMS| SPSrc [8:15] | SPSrc [0:7] | I-SID [16:23] | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | I-SID [8:15] | I-SID [0:7] | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Figure 1: SPBM Multicast Address Format + (SPSrcMS represents SPSrc [16:19]) + + Note: In Figure 1, the index numbering from less significant bit to + more significant bit within a byte or field within a byte gives + the wire order of the bits in the address consistent with the IETF + format in the rest of this document. (The IEEE convention for + number representation reverses the bits within an octet compared + with IETF practice.) + + o M is the multicast bit, always set to 1 for a multicast DA. (It + is the lowest bit in the most significant byte.) + + o L is the local bit, always set to 1 for an SPBM-constructed + multicast DA. + + o TYP is the SPSourceID type. 00 is the only type supported at this + time. + + o SPSrc (SPSourceID) is a 20-bit quantity that uniquely identifies a + SPBM node for all B-VIDs allocated to SPBM operation. This is + just the SPSourceID advertised in the SPB Instance (SPB-Inst) sub- + TLV. The value SPSourceID = 0 has special significance; it is + advertised by an SPBM node that has been configured to assign its + SPSourceID dynamically, which requires LSDB synchronization, but + where the SPSourceID assignment has not yet completed. + + o I-SID is the 24-bit I-Component Service ID advertised in the SPBM + Service Identifier TLV. It occupies the lower 24 bits of the SPBM + multicast DA. The I-SID value 0xfff is reserved for SPBM control + traffic (refer to the default I-SID in [802.1aq]). + + + +Fedyk, et al. Standards Track [Page 10] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + This multicast address format is used as the DA on frames when they + are first encapsulated at ingress to the SPBM network. The DA is + also installed into the FDBs on all SPBM nodes that are on the + corresponding SPT between the source and other nodes that have + registered receiver interest in the same I-SID. + + Just as with unicast forwarding, the B-SA/B-VID May be used to + perform an ingress check, but the SPSourceID encoded in the DA and + the "drop-on-unknown" functionality of the FDB in [PBB] achieve the + same effect. + + The I-Component at the egress SPBM device has completely standard + [PBB] behavior and therefore will: + + 1) learn the remote C-SA to B-SA relationship and + + 2) bridge the original customer frame to the set of local UNI ports + that are associated with the I-SID. + +4.5. Data Path SPBV Broadcast + + When a packet for an unknown DA arrives at an SPBV UNI port, VID + translation (or VID encapsulation for untagged Frames) with the + corresponding SPVID for this VLAN and ingress SPB is performed. + + SPVID forwarding is simply an SPT that follows normal VLAN forwarding + behavior, with the exception that the SPVID is unidirectional. As a + result, shared VLAN learning (SVL) is used between the forward- and + reverse-path SPVIDs associated with the same Base VID to allow SPBV + unicast forwarding to operate in the normal reverse learning fashion. + + Ingress check is done by simply verifying that the bridge to which + the SPVID has been assigned is indeed "shortest path" reachable over + the link over which the packet tagged with that SPVID arrived. This + is computed from the IS-IS database and is implied when the SPVID is + associated with a specific incoming port. + +4.6. Data Path SPBV Unicast + + When a packet for a known DA arrives at an SPBV UNI port, VID + translation (or VID encapsulation for untagged Frames) with the + corresponding SPVID for this VLAN and ingress bridge is performed. + + Since the SPVID will have been configured to follow a source-specific + SPT and the DA is known, the packet will follow the source-specific + path towards the destination C-MAC. + + Ingress check is as per the previous SPBV section. + + + +Fedyk, et al. Standards Track [Page 11] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + +4.7. Data Path SPBV Multicast + + C-DA multicast addresses May be advertised from SPBV UNI ports. + These may be configured or learned through the Multiple MAC + Registration Protocol (MMRP). MMRP is terminated at the edge of the + SPBV network and IS-IS carries the multicast addresses. Tandem SPBV + devices will check to see if they are on the SPF tree between SPBV + UNI ports advertising the same C-DA multicast address, and if so will + install multicast state to follow the SPBV SPF trees. + + Ingress check is as per the previous two SPBV sections. + +5. SPBM Example + + Consider the small example network shown in Figure 2. Nodes are + drawn in boxes with the last nibble of their B-MAC address :1..:7. + The rest of the B-MAC address nibbles are 4455-6677-00xx. Links are + drawn as "--" and "/", while the interface indexes are drawn as + numbers next to the links. UNI ports are shown as "<==>" with the + desired I-SID shown at the end of the UNI ports as "i1". + + +----+ +----+ + | :4 | 2 ------1 | :5 | <==> i1 + +----+ +----+ + 1 3 3 2 + / \ / \ + 1 4 3 2 + +----+ +----+ +----+ + i1 <==> | :1 | 2----1 | :2 | 2------1 | :3 | <==> i1 + +----+ +----+ +----+ + 3 6 5 3 + \ / \ / + 3 2 1 2 + +----+ +----+ + | :6 | 1-------3 | :7 | <==> i1 + +----+ +----+ + + Figure 2: SPBM Example 7-Node Network + + Using the default ECT-ALGORITHM (00-80-C2-01), which picks the equal + cost path with the lowest BridgeID, this ECT-ALGORITHM is assigned to + B-VID 100. When all links have the same cost, then the 1-hop + shortest paths are all direct and the 2-hop shortest paths (which are + of course symmetric) are as follows: + + { 1-2-3, 1-2-5, 1-2-7, 6-2-5, + 4-2-7, 4-1-6, 5-2-7, 6-2-3, 4-2-3 } + + + + +Fedyk, et al. Standards Track [Page 12] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + Node :1's unicast forwarding table therefore routes toward B-MACs :7, + :3, and :5 via interface/2, while its single-hop paths are all direct + as can be seen from its FDB given in Figure 3. + + Node :1 originates multicast since it is at the head of the MDT to + nodes :3, :5, and :7 and is a transmitter of I-SID 1, which nodes :3, + :5, and :7 all wish to receive. Node :1 therefore produces a + multicast forwarding entry whose DA contains its SPSourceID (which is + the last 20 bits of the B-MAC in the example) and the I-SID 1. Node + :1 thereafter sends packets matching this entry to interface if/2 + with B-VID=100. Node :1's full unicast (U) and multicast (M) table + is shown in Figure 3. Note that the IN/IF (incoming interface) field + is not specified for unicast traffic, and for multicast traffic has + to point back to the root of the tree, unless it is the head of the + tree -- in which case, we use the convention if/00. Since node :1 is + not transit for any multicast, it only has a single entry for the + root of its tree for I-SID=1. + + +-------+-------------------+------+-----------------+ + | IN/IF | DESTINATION ADDR | BVID | OUT/IF(s) | + +-------+-------------------+------+-----------------+ + U| if/** | 4455-6677-0002 | 0100 | {if/2 } + U| if/** | 4455-6677-0003 | 0100 | {if/2 } + U| if/** | 4455-6677-0004 | 0100 | {if/1 } + U| if/** | 4455-6677-0005 | 0100 | {if/2 } + U| if/** | 4455-6677-0006 | 0100 | {if/3 } + U| if/** | 4455-6677-0007 | 0100 | {if/2 } + M| if/00 | 7300-0100-0001 | 0100 | {if/2 } + + Figure 3: SPBM Node :1 FDB - Unicast (U) and Multicast (M) + + Node :2, being at the center of the network, has direct 1-hop paths + to all other nodes; therefore, its unicast FDB simply sends packets + with the given B-MAC/B-VID=100 to the interface directly to the + addressed node. This can be seen by looking at the unicast entries + (the first 6) shown in Figure 4. + + + + + + + + + + + + + + + +Fedyk, et al. Standards Track [Page 13] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + +-------+-------------------+------+-----------------+ + | IN/IF | DESTINATION ADDR | BVID | OUT/IF(s) | + +-------+-------------------+------+-----------------+ + U| if/** | 4455-6677-0001 | 0100 | {if/1 } + U| if/** | 4455-6677-0003 | 0100 | {if/2 } + U| if/** | 4455-6677-0004 | 0100 | {if/4 } + U| if/** | 4455-6677-0005 | 0100 | {if/3 } + U| if/** | 4455-6677-0006 | 0100 | {if/6 } + U| if/** | 4455-6677-0007 | 0100 | {if/5 } + M| if/01 | 7300-0100-0001 | 0100 | {if/2,if/3,if/5 } + M| if/02 | 7300-0300-0001 | 0100 | {if/1 } + M| if/03 | 7300-0500-0001 | 0100 | {if/1,if/5 } + M| if/05 | 7300-0700-0001 | 0100 | {if/1,if/3 } + + Figure 4: SPBM Node :2 FDB Unicast (U) and Multicast (M) + + Node :2's multicast is more complicated since it is a transit node + for the 4 members of I-SID=1; therefore, it requires 4 multicast FDB + entries depending on which member it is forwarding/replicating on + behalf of. For example, node :2 is on the shortest path between each + of nodes {:3, :5, :7} and :1. So it must replicate from node :1 + I-SID 1 out on interfaces { if/2, if/3 and if/5 } (to reach nodes :3, + :5, and :7). It therefore creates a multicast DA with the SPSourceID + of node :1 together with I-SID=1, which it expects to receive over + interface/1 and will replicate out interfaces { if/2, if/3 and if/5 + }. This can be seen in the first multicast entry in Figure 4. + + + Note that node :2 is not on the shortest path between nodes :3 and :5 + nor between nodes :3 and :7; however, it still has to forward packets + to node :1 from node :3 for this I-SID, which results in the second + multicast forwarding entry in Figure 4. Likewise, for packets + originating at nodes :5 or :7, node :2 only has to replicate twice, + which results in the last two multicast forwarding entries in Figure + 4. + +6. SPBV Example + + Using the same example network as Figure 2, we will look at the FDBs + produced for SPBV mode forwarding. Nodes :1, :5, :3, and :7 wish to + transmit and receive the same multicast MAC traffic using multicast + address 0300-0000-000f and at the same time require congruent and + symmetric unicast forwarding. In SPBV mode, the only encapsulation + is the C-TAG or S-TAG, and the MAC addresses SA and DA are reverse- + path learned, as in traditional bridging. + + + + + + +Fedyk, et al. Standards Track [Page 14] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + +----+ +----+ + | :4 | 2 ------1 | :5 | <==> MMAC ..:f + +----+ +----+ + 1 3 3 2 + / \ / \ + 1 4 3 2 + +----+ +----+ +----+ + MMAC<==> | :1 | 2----1 | :2 | 2------1 | :3 | <==> MMAC ..:f + ..:f +----+ +----+ +----+ + 3 6 5 3 + \ / \ / + 3 2 1 2 + +----+ +----+ + | :6 | 1-------3 | :7 | <==> MMAC ..:f + +----+ +----+ + + Figure 5: SPBV Example 7-Node Network + + Assuming the same ECT-ALGORITHM (00-80-C2-01), which picks the equal + cost path with the lowest BridgeID, this ECT-ALGORITHM is assigned to + Base VID 100, and for each node the SPVID = Base VID + Node ID (i.e., + 101, 102..107). When all links have the same cost, then the 1-hop + shortest paths are all direct, and the 2-hop shortest paths (which + are of course symmetric) are as previously given for Figure 2. + + Node :1's SPT for this ECT-ALGORITHM is therefore (described as a + sequence of unidirectional paths): + + { 1->4, 1->6, 1->2->3, 1->2->5, 1->2->7 } + + The FDBs therefore must have entries for the SPVID reserved for + packets originating from node :1, which in this case is VID=101. + + Node :2 therefore has an FDB that looks like Figure 6. In + particular, it takes packets from VID 101 on interface/01 and sends + to nodes :3, :5, and :7 via if/2, if/3, and if/5. It does not + replicate anywhere else because the other nodes (:4 and :6) are + reached by the SPT directly from node :1. The rest of the FDB + unicast entries follow a similar pattern; recall that the shortest + path between :4 and :6 is via node :1, which explains replication + onto only two interfaces from if/4 and if/6. Note that the + destination addresses are wild cards, and SVL exists between these + SPVIDs because they are all associated with Base VID = 100, which + defines the VLAN being bridged. + + + + + + + +Fedyk, et al. Standards Track [Page 15] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + +-------+-------------------+------+-----------------+ + | IN/IF | DESTINATION ADDR | VID | OUT/IF(s) | + +-------+-------------------+------+-----------------+ + U| if/01 | ************** | 0101 | {if/2,if/3,if/5 } + U| if/02 | ************** | 0103 | {if/1,if/4,if/6 } + U| if/04 | ************** | 0104 | {if/2,if/5 } + U| if/03 | ************** | 0105 | {if/1,if/5,if/6 } + U| if/06 | ************** | 0106 | {if/2,if/3 } + U| if/05 | ************** | 0107 | {if/1,if/3,if/4 } + + Figure 6: SPBV Node :2 FDB Unicast + + Now, since nodes :5, :3, :7 and :1 are advertising membership in the + same multicast group address :f, Node 2 requires additional entries + to replicate just to these specific nodes for the given multicast + group address. These additional multicast entries are given below in + Figure 7. + + +-------+-------------------+------+-----------------+ + | IN/IF | DESTINATION ADDR | VID | OUT/IF(s) | + +-------+-------------------+------+-----------------+ + M| if/01 | 0300-0000-000f | 0101 | {if/2,if/3,if/5 } + M| if/02 | 0300-0000-000f | 0103 | {if/1 } + M| if/03 | 0300-0000-000f | 0105 | {if/1,if/5 } + M| if/05 | 0300-0000-000f | 0107 | {if/1,if/3 } + + Figure 7: SPBV Node :2 FDB Multicast (M) + +7. SPB Supported Adjacency types + + IS-IS for SPB currently only supports peer-to-peer adjacencies. + Other link types are for future study. As a result, pseudonodes and + links to/from pseudonodes are not considered as part of the IS-IS SPF + computations and will be avoided if present in the physical topology. + Other NLPIDs MAY of course use them as per normal. + + IS-IS for SPB Must use the IS-IS three-way handshake for IS-IS point- + to-point adjacencies described in RFC 5303. + +8. SPB IS-IS Adjacency Addressing + + The default behavior of 802.1aq is to use the normal IS-IS Ethernet + multicast addresses for IS-IS. + + There are however additional Ethernet multicast addresses that have + been assigned for 802.1aq for special use cases. These do not in any + way change the state machinery or packet formats of IS-IS but simply + + + + +Fedyk, et al. Standards Track [Page 16] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + recommend and reserve different multicast addresses. Refer to + [802.1aq] for additional details. + +9. IS-IS Area Address and SYSID + + A stand-alone implementation (supporting ONLY the single NLPID=0xC1) + of SPB Must use an IS-IS area address value of 0, and the SYSID Must + be the well-known MAC address of the SPB device. + + Non-stand-alone implementations (supporting other NLPIDs) MUST use + the normal IS-IS rules for the establishment of a level 1 domain + (i.e., multiple area addresses are allowed only where immediate + adjacencies share a common area address). Level 2 operations of + course place no such restriction on adjacent area addresses. + +10. Level 1/2 Adjacency + + SPBV and SPBM will operate within either an IS-IS level 1 or level 2. + As a result, the TLVs specified here MAY propagate in either level 1 + or level 2 LSPs. IS-IS SPB implementations Must support level 1 and + May support level 2 operations. Hierarchical SPB is for further + study; therefore, these TLVs Should Not be leaked between level 1 and + level 2. + +11. Shortest Path Default Tie-Breaking + + The default algorithm is ECT-Algorithm = 00-80-c2-01. + + Two mechanisms are used to ensure symmetry and determinism in the + shortest path calculations. + + The first mechanism addresses the problem when different ends (nodes) + of an adjacency advertise different values for the SPB-LINK-METRIC. + To solve this, SPB shortest path calculations Must use the maximum + value of the two nodes' advertised SPB-LINK-METRICs when accumulating + and minimizing the (sub)path costs. + + The second mechanism addresses the problem when two equal sums of + link metrics (sub)paths are found. To solve this, the (sub)path with + the fewest hops between the fork/join points Must win the tie. + However, if both (sub)paths have the same number of hops between the + fork and join points, then the default tie-breaking Must pick the + path traversing the intermediate node with the lower BridgeID. The + BridgeID is an 8-byte quantity whose upper 2 bytes are the node's + BridgePriority and lower 6 bytes are the node's SYSID. + + + + + + +Fedyk, et al. Standards Track [Page 17] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + For example, consider the network in Figure 2 when a shortest path + computation is being done from node :1. Upon reaching node :7, two + competing sub-paths fork at node :1 and join at node :7, the first + via :2 and the second via :6. Assuming that all the nodes advertise + a Bridge Priority of 0, the default tie-breaking rule causes the path + traversing node :2 to be selected since it has a lower BridgeID + {0...:2} than node :6 {0...:6}. Note that the operator may cause the + tie-breaking logic to pick the alternate path by raising the Bridge + Priority of node :2 above that of node :6. + + The above algorithm guarantees symmetric and deterministic results in + addition to having the critical property of transitivity (shortest + path is made up of sub-shortest paths). + +12. Shortest Path ECT + + Standard ECT Algorithms initially have been proposed ranging from + 00-80-c2-01 to 00-80-c2-10. + + To create diversity in routing, SPB defines 16 variations on the + above default tie-breaking algorithm; these have worldwide unique + designations 00-80-C2-01 through 00-80-C2-10. These designations + consist of the IEEE 802.1 OUI (Organizationally Unique Identifier) + value 00-80-C2 concatenated with indexes 0X01..0X10. These + individual algorithms are implemented by selecting the (sub)path with + the lowest value of: + + XOR BYTE BY BYTE(ECT-MASK{ECT-ALGORITHM.index},BridgeID) + + Where: + + ECT-MASK{17} = { 0x00, 0x00, 0xFF, 0x88, + 0x77, 0x44, 0x33, 0xCC, + 0xBB, 0x22, 0x11, 0x66, + 0x55, 0xAA, 0x99, 0xDD, + 0xEE }; + + XOR BYTE BY BYTE - XORs BridgeID bytes with ECT-MASK + + ECT-MASK{1}, since it XORs with all zeros, yields the default + algorithm described above (00-80-C2-01); while ECT-MASK{2}, since it + XORs with a mask of all ones, will invert the BridgeID, essentially + picking the path traversing the largest Bridge ID. The other ECT- + MASKs produce diverse alternatives. In all cases, the + BridgePriority, since it is the most significant part of the + BridgeID, permits overriding the SYSID as the selection criteria and + gives the operator a degree of control on the chosen ECT paths. + + + + +Fedyk, et al. Standards Track [Page 18] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + To support many other tie-breaking mechanisms in the future, two + opaque ECT TLVs are defined, which may be used to provide parameters + to ECT-ALGORITHMs outside of the currently defined space. + + ECT-ALGORITHMs are mapped to VIDs, and then services can be assigned + to those VIDs. This permits a degree of traffic engineering since + service assignment to VID is consistent end to end through the + network. + +13. Hello (IIH) Protocol Extensions + + IEEE 802.1aq can run in parallel with other network layer protocols + such as IPv4 and IPv6; therefore, failure of two SPB nodes to + establish an adjacency MUST NOT cause rejection of an adjacency for + the purposes of other network layer protocols. + + IEEE 802.1aq has been assigned the NLPID value 0xC1 [RFC6328], which + MUST be used by Shortest Path Bridges (SPBs) to indicate their + ability to run 802.1aq. This is done by including this NLPID value + in the IS-IS IIH PDU Protocols Supported TLV (type 129). 802.1aq + frames MUST only flow on adjacencies that advertise this NLPID in + both directions of the IIH PDUs. 802.1aq computations MUST consider + an adjacency that has not advertised 0xC1 NLPID in both directions as + non-existent (infinite link metric) and MUST ignore any IIH SPB TLVs + they receive over such adjacencies. + + + IEEE 802.1aq augments the normal IIH PDU with three new TLVs, which + like all other SPB TLVs, travel within Multi-Topology [MT] TLVs, + therefore allowing multiple logical instances of SPB within a single + IS-IS protocol instance. + + Since SPB can use many VIDs and Must agree on which VIDs are used for + which purposes, the IIH PDUs carry a digest of all the used VIDs (on + the NNIs) referred to as the SPB-MCID TLV, which uses a common and + compact encoding reused from 802.1Q. + + SPB neighbors May support a mechanism to verify that the contents of + their topology databases are synchronized (for the purposes of loop + prevention). This is done by exchanging a digest of SPB topology + information (computed over all MT IDs) and taking specific actions on + forwarding entries when the digests indicate a mismatch in topology. + This digest is carried in the Optional SPB-Digest sub-TLV. + + Finally, SPB needs to know which SPT Sets (defined by ECT-ALGORITHMs) + are being used by which VIDs, and this is carried in the Base VLAN + Identifiers (SPB-B-VID) sub-TLV. + + + + +Fedyk, et al. Standards Track [Page 19] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + +13.1. SPB-MCID Sub-TLV + + This sub-TLV is added to an IIH PDU to indicate the digest for the + multiple spanning tree configuration a.k.a. MCID. This TLV is a + digest of local configuration of which VIDs are running which + protocols. (The information is not to the level of a specific + algorithm in the case of SPB.) This information Must be the same on + all bridges in the SPT Region controlled by an IS-IS instance. The + data used to generate the MCID is populated by configuration and is a + digest of the VIDs allocated to various protocols. Two MCIDs are + carried to allow non-disruptive transitions between configurations + when the changes are non-critical. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+ + |Type=SPB-MCID | = 4 + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | MCID (51 Bytes) | + | ............... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Aux MCID (51 Bytes) | + | ............... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: sub-TLV type 4. + + o Length: The size of the value defined below (102). + + o MCID (51 bytes): The complete MCID defined in IEEE 802.1Q, which + identifies an SPT Region on the basis of matching assignments of + VIDs to control regimes (xSTP, SPBV, SPBM, etc.). Briefly, the + MCID consists of a 1-byte format selector, a 32-byte configuration + name, a 2-byte revision level, and finally a 16-byte signature of + type HMAC-MD5 over an array of 4096 elements that contain + identifiers of the use of the corresponding VID. Refer to Section + 13.8 of [802.1aq] for the exact format and procedure. Note that + the use of the VID does not include specification of a specific + SPB ECT-ALGORITHM; rather, it is coarser grain. + + o Aux MCID (51 bytes): The complete MCID defined in IEEE 802.1Q, + which identifies an SPT Region. The aux MCID allows SPT Regions + to be migrated by the allocation of new VLAN to FDB Mappings + without interruption to existing traffic. + + + + + +Fedyk, et al. Standards Track [Page 20] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + The SPB-MCID sub-TLV is carried within the MT-Port-Cap TLV [RFC6165] + with the MT ID value of 0, which in turn is carried in an IIH PDU. + +13.2. SPB-Digest Sub-TLV + + This sub-TLV is Optionally added to an IIH PDU to indicate the + current SPB topology digest value. It is always carried in an + MT-Port-Cap TLV [RFC6165] with an MT ID value of 0. This information + should settle to be the same on all bridges in an unchanging + topology. Matching digests indicate (with extremely high + probability) that the topology view between two SPBs is synchronized; + this match (or lack of match) is used to control the updating of + forwarding information. The SPB Agreement Digest is computed based + on contributions derived from the current topologies of all SPB MT + instances and is designed to change when significant topology changes + occur within any SPB instance. + + During the propagation of LSPs, the Agreement Digest may vary between + neighbors until the key topology information in the LSPs is common. + The digest is therefore a summarized means of determining agreement + between nodes on database commonality, and hence of inferring + agreement on the distance to all multicast roots. When present, it + is used for loop prevention as follows: for each shortest path tree + where it has been determined the distance to the root has changed, + "unsafe" multicast forwarding is blocked until the exchanged + Agreement Digests match, while "safe" multicast forwarding is allowed + to continue despite the disagreement in digests and hence topology + views. Section 28.2 of [802.1aq] defines in detail what constitutes + "safe" vs. "unsafe". + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+ + |Type=SPB-Digest| = 5 + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-----+-+---+---+ + | Res |V| A | D | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Agreement Digest (Length - 1) | + | ............... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: sub-TLV type 5. + + o Length: The size of the value. + + o V bit: Agreed digest valid bit. See Section 28.2 of [802.1aq]. + + + +Fedyk, et al. Standards Track [Page 21] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + o A (2 bits): The Agreement Number 0-3, which aligns with the BPDU's + Agreement Number concept [802.1aq]. When the Agreement Digest for + this node changes, this number is incremented. The node then + checks for Agreement Digest match (as below). The new local + Agreement Number and the updated local Discarded Agreement Number + are then transmitted with the new Agreement Digest to the node's + neighbors in the Hello PDU. Once an Agreement Number has been + sent, it is considered outstanding until a matching or more recent + Discarded Agreement Number is received from the neighbor. + + o D (2 bits): The Discarded Agreement Number 0-3, which aligns with + BPDU's Agreement Number concept. When an Agreement Digest is + received from a neighbor, this number is set to the received + Agreement Number to signify that this node has received this new + agreement and discarded any previous ones. The node then checks + whether the local and received Agreement Digests match. If they + do, this node then sets: + + the local Discarded Agreement Number = received Agreement Number + + 1 + + If the Agreement Digests match, AND received Discarded Agreement + Number == + local Agreement Number + N (N = 0 || 1) + + then the node has a topology matched to its neighbor. + + Whenever the local Discarded Agreement Number relating to a + neighbor changes, the local Agreement Digest, Agreement Number, + and Discarded Agreement Number are transmitted. + + o Agreement Digest. This digest is used to determine when SPB is + synchronized between neighbors for all SPB instances. The + Agreement Digest is a hash computed over the set of all SPB + adjacencies in all SPB instances. In other words, the digest + includes all VIDs and all adjacencies for all MT instances of SPB + (but not other network layer protocols). This reflects the fact + that all SPB nodes in a region Must have identical VID allocations + (see Section 13.1), and so all SPB instances will contain the same + set of nodes. The exact procedure for computing the Agreement + Digest and its size are defined in Section 28.2 of [802.1aq]. + + The SPB-Digest sub-TLV is carried within the MT-Port-Cap TLV + [RFC6165] (with the MT ID value 0), which in turn is carried in an + IIH PDU. + + When supported, this sub-TLV MUST be carried on every IIH between SPB + neighbors, not just when a Digest changes. + + + +Fedyk, et al. Standards Track [Page 22] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + When one peer supports this TLV and the other does not, loop + prevention by Agreement Digest Must Not be done by either side. + +13.3. SPB Base VLAN Identifiers (SPB-B-VID) Sub-TLV + + This sub-TLV is added to an IIH PDU to indicate the mappings between + ECT algorithms and Base VIDs (and by implication the VID(s) used on + the forwarding path for each SPT Set for a VLAN identified by a Base + VID) that are in use. Under stable operational conditions, this + information should be the same on all bridges in the topology + identified by the MT-Port-Cap TLV [RFC6165] it is being carried + within. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+ + |Type= SPB-B-VID| = 68 + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-----------------------------------------------+ + | ECT-VID Tuple (1) (6 bytes) | + +---------------------------------+-----------------------------+ + | ... | ECT-VID Tuple(2) (6 bytes) | + +---------------------------------+-----------------------------+ + | ..... | + +---------------------------------------------------------------+ + | ..... | + | ..... | + +---------------------------------------------------------------+ + + o Type: sub-TLV type 6. + + o Length: The size of the value is ECT-VID Tuples*6 bytes. Each + 6-byte part of the ECT-VID tuple is formatted as follows: + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ECT-ALGORITHM (32 bits) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Base VID (12 bits) |U|M|RES| + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o ECT-ALGORITHM (4 bytes): The ECT-ALGORITHM is advertised when the + bridge supports a given ECT-ALGORITHM (by OUI/Index) on a given + Base VID. There are 17 predefined IEEE algorithms for SPB with + index values 0X00..0X10 occupying the low 8 bits and the IEEE + OUI=00-80-C2 occupying the top 24 bits of the ECT-ALGORITHM. + + + +Fedyk, et al. Standards Track [Page 23] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + o Base VID (12 bits): The Base VID that is associated with the SPT + Set. + + o Use-Flag (1 bit): The Use-Flag is set if this bridge, or any + bridge in the LSDB, is currently using this ECT-ALGORITHM and Base + VID. Remote usage is discovered by inspection of the U bit in the + SPB-Inst sub-TLV of other SPB bridges (see Section 14.1) + + o M bit (1 bit): The M bit indicates if this Base VID operates in + SPBM (M = 1) or SPBV (M = 0) mode. + + The SPB-B-VID sub-TLV is carried within the MT-Port-Cap TLV + [RFC6165], which in turn is carried in an IIH PDU. + +14. Node Information Extensions + + All SPB nodal information extensions travel within a new multi- + topology capability TLV MT-Capability (type 144). + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+ + |Type = MT-CAP | = 144 + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |O R R R| MT ID | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + (sub-TLVs ... ) + + The format of this TLV is identical in its first 2 bytes to all + current MT TLVs and carries the MT ID as defined in [MT]. + + The O (overload) bit carried in bit 16 has the same semantics as + specified in [MT], but in the context of SPB adjacencies only. + + There can be multiple MT-Capability TLVs present, depending on the + amount of information that needs to be carried. + +14.1. SPB Instance (SPB-Inst) Sub-TLV + + The SPB-Inst sub-TLV gives the SPSourceID for this node/topology + instance. This is the 20-bit value that is used in the formation of + multicast DAs for frames originating from this node/instance. The + SPSourceID occupies the upper 20 bits of the multicast DA together + with 4 other bits (see the SPBM 802.1ah multicast DA address format + section). This sub-TLV MUST be carried within the MT-Capability TLV + in the fragment ZERO LSP. If there is an additional SPB instance, it + + + +Fedyk, et al. Standards Track [Page 24] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + MUST be declared under a separate MT-Capability TLV and also carried + in the fragment ZERO LSP. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+ + |Type = SPB-Inst| = 1 + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | CIST Root Identifier (4 bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | CIST Root Identifier (cont) (4 bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | CIST External Root Path Cost (4 bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Bridge Priority | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |R R R R R R R R R R R|V| SPSourceID | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Num of Trees | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | VLAN-ID (1) Tuples (8 bytes) | + | ........................... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + ........................... + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | VLAN-ID (N) Tuples (8 bytes) | + | ........................... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + where VLAN-ID tuples have the format as: + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+ + |U|M|A| Res | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ECT-ALGORITHM (32 bits) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Base VID (12 bits) | SPVID (12 bits) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: sub-TLV type 1. + + o Length: Total number of bytes contained in the value field. + + + + + +Fedyk, et al. Standards Track [Page 25] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + o CIST Root Identifier (64 bits): The CIST Root Identifier is for + SPB interworking with Rapid STP (RSTP) and Multiple STP (MSTP) at + SPT Region boundaries. This is an imported value from a spanning + tree. + + o CIST External Root Path Cost (32 bits): The CIST External Root + Path Cost is the cost to root, derived from the spanning tree + algorithm. + + o Bridge Priority (16 bits): Bridge priority is the 16 bits that + together with the 6 bytes of the System ID form the Bridge + Identifier. This allows SPB to build a compatible spanning tree + using link state by combining the Bridge Priority and the System + ID to form the 8-byte Bridge Identifier. The 8-byte Bridge + Identifier is also the input to the 16 predefined ECT tie-breaker + algorithms. + + o V bit (1 bit): The V bit (SPBM) indicates this SPSourceID is auto- + allocated (Section 27.11 of [802.1aq]). If the V bit is clear, + the SPSourceID has been configured and Must be unique. Allocation + of SPSourceID is defined in IEEE [802.1aq]. Bridges running SPBM + will allocate an SPSourceID if they are not configured with an + explicit SPSourceID. The V bit allows neighbor bridges to + determine if the auto-allocation was enabled. In the rare chance + of a collision of SPsourceID allocation, the bridge with the + highest priority Bridge Identifier will win conflicts. The lower + priority bridge will be re-allocated; or, if the lower priority + bridge is configured, it will not be allowed to join the SPT + Region. + + o SPSourceID: a 20-bit value used to construct multicast DAs as + described below for multicast frames originating from the origin + (SPB node) of the Link State Packet (LSP) that contains this TLV. + More details are in IEEE [802.1aq]. + + o Number of Trees (8 bits): The Number of Trees is set to the number + of {ECT-ALGORITHM, Base VID plus flags} tuples that follow. Each + ECT-ALGORITHM has a Base VID, an SPVID, and flags described below. + This Must contain at least the one ECT-ALGORITHM (00-80-C2-01). + + Each VID Tuple consists of: + + o U bit (1 bit): The U bit is set if this bridge is currently using + this ECT-ALGORITHM for I-SIDs it sources or sinks. This is a + strictly local indication; the semantics differ from the Use-Flag + found in the Hello, which will set the Use-Flag if it sees other + nodal U bits are set OR it sources or sinks itself. + + + + +Fedyk, et al. Standards Track [Page 26] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + o M bit (1 bit): The M bit indicates if this is SPBM or SPBV mode. + When cleared, the mode is SPBV; when set, the mode is SPBM. + + o A bit (1 bit): The A bit (SPB), when set, declares this is an + SPVID with auto-allocation. The VID allocation logic details are + in IEEE [802.1aq]. Since SPVIDs are allocated from a small pool + of 12-bit resources, the chances of collision are high. To + minimize collisions during auto-allocation, LSPs are initially + advertised with the originating bridge setting the SPVID to 0. + Only after learning the other bridges' SPVID allocations does this + bridge re-advertise this sub-TLV with a non-zero SPVID. This will + minimize but not eliminate the chance of a clash. In the event of + a clash, the highest Bridge Identifier is used to select the + winner, while the loser(s) with lower Bridge Identifier(s) Must + withdraw their SPVID allocation(s) and select an alternative + candidate for another trial. SPVID May also be configured. When + the A bit is set to not specify auto-allocation and the SPVID is + set to 0, this SPBV bridge is used for transit only within the SPB + region. If a port is configured with the Base VID as a neighbor + using RSTP or MSTP, the bridge will act as an ingress filter for + that VID. + + o ECT-ALGORITHM (4 bytes): ECT-ALGORITHM is advertised when the + bridge supports a given ECT-ALGORITHM (by OUI/Index) on a given + VID. This declaration Must match the declaration in the Hello PDU + originating from the same bridge. The ECT-ALGORITHM and Base VID + Must match what is generated in the IIHs of the same node. The + ECT-ALGORITHM, Base VID tuples can come in any order, however. + There are currently 17 worldwide unique 802.1aq defined ECT- + ALGORITHMs given by values 00-80-C2-00 through 00-80-C2-10. + + o Base VID (12 bits): The Base VID that associated the SPT Set via + the ECT-ALGORITHM. + + o SPVID (12 bits): The SPVID is the Shortest Path VID assigned for + the Base VID to this node when using SPBV mode. It is not defined + for SPBM mode and Must be 0 for SPBM mode B-VIDs. + + + + + + + + + + + + + + +Fedyk, et al. Standards Track [Page 27] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + +14.1.1. SPB Instance Opaque ECT-ALGORITHM (SPB-I-OALG) Sub-TLV + + There are multiple ECT algorithms defined for SPB; however, for the + future, additional algorithms may be defined including but not + limited to ECMP- or hash-based behaviors and (*,G) multicast trees. + These algorithms will use this Optional TLV to define new algorithm + parametric data. For tie-breaking parameters, there are two broad + classes of algorithm, one that uses nodal data to break ties and one + that uses link data to break ties. This sub-TLV is used to associate + opaque tie-breaking data with a node. This sub-TLV, when present, + MUST be carried within the MT-Capability TLV (along with a valid SPB- + Inst sub-TLV). Multiple copies of this sub-TLV MAY be carried for + different ECT-ALGORITHMs relating to this node. + + There are of course many other uses of this opaque data that have yet + to be defined. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+ + |Type=SPB-I-OALG| = 2 + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Opaque ECT-ALGORITHM (4 bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Opaque ECT Information (variable) | + | ....................... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: sub-TLV type 2. + + o Length: Total number of bytes contained in the value field. + + o ECT-ALGORITHM: ECT-ALGORITHM is advertised when the bridge + supports a given ECT-ALGORITHM (by OUI/Index) on a given VID. + + o ECT Information: ECT-ALGORITHM Information of variable length + which SHOULD be in sub-TLV format with an IANA numbering space + where appropriate. + + + + + + + + + + + +Fedyk, et al. Standards Track [Page 28] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + +15. Adjacency Information Extensions + +15.1. SPB Link Metric (SPB-Metric) Sub-TLV + + The SPB-Metric sub-TLV (type 29) occurs within the Multi-Topology + Intermediate System Neighbor (MT-ISN) TLV (type 222) or within the + Extended IS Reachability TLV (type 22). If this sub-TLV is not + present for an IS-IS adjacency, then that adjacency Must not carry + SPB traffic for the given topology instance. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+ + |Type=SPB-Metric| = 29 + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | SPB-LINK-METRIC | (3 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Num of Ports | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Port Identifier | ( 2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: sub-TLV type 29. + + o Length: Total number of bytes contained in the value field. + + o SPB-LINK-METRIC: the administrative cost or weight of using this + link as a 24-bit unsigned number. This metric applies to the use + of this link for SPB traffic only. Smaller numbers indicate lower + weights and are more likely to carry SPB traffic. Only one metric + is allowed per SPB instance per link. If multiple metrics are + required, multiple SPB instances Must be used, either within IS-IS + or within several independent IS-IS instances. If this metric is + different at each end of a link, the maximum of the two values + Must be used in all SPB calculations for the weight of this link. + The maximum SPB-LINK-METRIC value 2^24 - 1 has a special + significance; this value indicates that although the IS-IS + adjacency has formed, incompatible values have been detected in + parameters configured within SPB itself (for example, different + regions), and the link Must Not be used for carrying SPB traffic. + Full details are found in [802.1aq]. + + o Num of Ports: the number of ports associated with this link. + + o Port Identifier: the standard IEEE port identifier used to build a + spanning tree associated with this link. + + + +Fedyk, et al. Standards Track [Page 29] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + +15.1.1. SPB Adjacency Opaque ECT-ALGORITHM (SPB-A-OALG) Sub-TLV + + There are multiple ECT algorithms defined for SPB; however, for the + future, additional algorithms may be defined. The SPB-A-OALG sub-TLV + occurs within the Multi-Topology Intermediate System TLV (type 222) + or the Extended IS Reachability TLV (type 22). Multiple copies of + this sub-TLV MAY be carried for different ECT-ALGORITHMs related to + this adjacency. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+ + |Type=SPB-A-OALG| = 30 + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Opaque ECT Algorithm (4 bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Opaque ECT Information (variable) | + | ......................... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: sub-TLV type 30. + + o Length: Total number of bytes contained in the value field. + + o ECT-ALGORITHM: ECT-ALGORITHM is advertised when the bridge + supports a given ECT-ALGORITHM (by OUI/Index) on a given VID. + + o ECT Information: ECT-ALGORITHM Information of variable length in + sub-TLV format using new IANA type values as appropriate. + +16. Service Information Extensions + +16.1. SPBM Service Identifier and Unicast Address (SPBM-SI) Sub-TLV + + The SPBM-SI sub-TLV (type 3) is used to introduce service group + membership on the originating node and/or to advertise an additional + B-MAC unicast address present on, or reachable by the node. + + + + + + + + + + + + +Fedyk, et al. Standards Track [Page 30] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+ + |Type = SPBM-SI | = 3 + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | B-MAC ADDRESS | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | B-MAC ADDRESS (6 bytes) | Res. | Base VID (12 bits) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |T|R| Reserved | I-SID #1 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |T|R| Reserved | I-SID #2 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + ................. + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |T|R| Reserved | I-SID #n | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: sub-TLV type 3. + + o Length: Total number of bytes contained in the value field. + + o B-MAC ADDRESS: a unicast address of this node. It may be the + single nodal address, or it may address a port or any other level + of granularity relative to the node. In the case where the node + only has one B-MAC address, this Should be the same as the SYSID + of the node. To add multiple B-MACs this TLV MUST be repeated per + additional B-MAC. + + o Base VID (12 bits): The Base VID associated with the B-BMAC allows + the linkage to the ECT-ALGORITHM and SPT Set defined in the SPB- + Inst sub-TLV. + + o I-SID #1 .. #n: 24-bit service group membership identifiers. If + two nodes have an I-SID in common, intermediate nodes on the + unique shortest path between them will create forwarding state for + the related B-MAC addresses and will also construct multicast + forwarding state using the I-SID and the node's SPSourceID to + construct a multicast DA as described in IEEE 802.1aq LSB. Each + I-SID has a Transmit (T) and Receive (R) bit that indicates if the + membership is as a transmitter, a receiver, or both (with both + bits set). In the case where the Transmit (T) and Receive (R) + bits are both zero, the I-SID instance is ignored for the purposes + of distributed multicast computation, but the unicast B-MAC + address Must be processed and installed at nodes providing transit + to that address. If more I-SIDs are associated with a particular + + + +Fedyk, et al. Standards Track [Page 31] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + B-MAC than can fit in a single sub-TLV, this sub-TLV can be + repeated with the same B-MAC but with different I-SID values. + + o Note: When the T bit is not set, an SPB May still multicast to all + the other receiving members of this I-SID (those advertising with + their R bits set), by configuring edge replication and serial + unicast to each member locally. + + The SPBM-SI sub-TLV, when present, MUST be carried within the + MT-Capability TLV and can occur multiple times in any LSP fragment. + +16.2. SPBV MAC Address (SPBV-ADDR) Sub-TLV + + The SPBV-ADDR sub-TLV is IS-IS sub-TLV type 4. It Should be used for + advertisement of Group MAC addresses in SPBV mode. Unicast MAC + addresses will normally be distributed by reverse-path learning, but + carrying them in this TLV is not precluded. It has the following + format: + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+ + | Type=SPBV-ADDR| = 4 (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |R|R| SR| SPVID | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+-+-+-+ + |T|R| Reserved | MAC 1 Address | (1+6 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+-+-+-+ + ... + +-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+-+-+-+ + |T|R| Reserved | MAC N Address | (1+6 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: sub-TLV type 4. + + o Length: Total number of bytes contained in the value field. The + number of MAC address associated with the SPVID is computed by + (Length - 2)/7. + + o SR bits (2 bits): The SR bits are the service requirement + parameter from MMRP. The service requirement parameters have the + value 0 (Forward all Groups) and 1 (Forward All Unregistered + Groups) defined. However, this attribute May also be missing. So + the SR bits are defined as 0 not declared, 1 Forward all Groups, + and 2 Forward All Unregistered Groups. The two 'R' reserved bits + + + + +Fedyk, et al. Standards Track [Page 32] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + immediately preceding these SR bits Shall be set to zero when + originating this sub-TLV and Shall be ignored on receipt. + + o SPVID (12 bits): The SPVID and by association Base VID and the + ECT-ALGORITHM and SPT Set that the MAC addresses defined below + will use. If the SPVID is not allocated the SPVID Value is 0. + Note that if the ECT-ALGORITHM in use is spanning tree algorithm + this value Must be populated with the Base VID and the MAC Must be + populated. + + o T bit (1 bit): This is the Transmit allowed bit for a following + group MAC address. This is an indication that the Group MAC + address in the context of the SPVID of the bridge advertising this + Group MAC Must be installed in the FDB of transit bridges, when + the bridge computing the trees is on the corresponding ECT- + ALGORITHM shortest path between the bridge advertising this MAC + with the T bit set and any receiver of this Group MAC address. A + bridge that does not advertise this bit set for a MAC address Must + Not cause multicast forwarding state to be installed on other + transit bridges in the network for traffic originating from that + bridge. + + o R bit (1 bit): This is the Receive allowed bit for the following + MAC address. This is an indication that MAC addresses as the + receiver Must be populated and installed when the bridge computing + the trees lies on the corresponding shortest path for this ECT- + ALGORITHM between this receiver and any transmitter to this MAC + address. An entry that does not have this bit set for a Group MAC + address is prevented from receiving on this Group MAC address + because transit bridges Must Not install multicast forwarding + state towards it in their FDBs. + + o MAC Address (48 bits): The MAC address declares this bridge as + part of the multicast interest for this destination MAC address. + Multicast trees can be efficiently constructed for destination by + populating FDB entries for the subset of the shortest path tree + that connects the bridges supporting the MAC address. This + replaces the function of MMRP for SPTs. The T and R bits above + have meaning as specified above. + + The SPBV-ADDR sub-TLV, when present, MUST be carried within the + MT-Capability TLV and can occur multiple times in any LSP fragment. + + + + + + + + + +Fedyk, et al. Standards Track [Page 33] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + +17. Security Considerations + + This document adds no additional security risks to IS-IS, nor does it + provide any additional security for IS-IS when used in a configured + environment or a single-operator domain such as a data center. + + However, this protocol may be used in a zero-configuration + environment. Zero configuration may apply to the automatic detection + and formation of an IS-IS adjacency (forming an NNI port). Likewise, + zero configuration may apply to the automatic detection of VLAN- + tagged traffic and the formation of a UNI port, with resultant I-SID + advertisements. + + If zero configuration methods are used to autoconfigure NNIs or UNIs, + there are intrinsic security concerns that should be mitigated with + authentication procedures for the above cases. Such procedures are + beyond the scope of this document and are yet to be defined. + + In addition, this protocol can create significant amounts of + multicast state when an I-SID is advertised with the T bit set. + Extra care should be taken to ensure that this cannot be used in a + denial-of-service attack [RFC4732] in a zero-configuration + environment. + +18. IANA Considerations + + Note that the NLPID value 0xC1 [RFC6328] used in the IIH PDUs has + already been assigned by IANA for the purpose of 802.1aq; therefore, + no further action is required for this code point. + + Since 802.1aq operates within the IS-IS Multi-Topology framework, + every sub-TLV MUST occur in the context of the proper MT TLV (with + the exception of the SPB-Metric sub-TLV, which MAY travel in TLV 22 + where its MT ID is unspecified but implied to be 0). IANA has + allocated sub-TLVs for three Multi-Topology TLVs per 802.1aq. These + are the MT-Port-Cap TLV [RFC6165] used in the IIH, the MT-Capability + TLV (new) used within the LSP, and finally the MT-ISN TLV [MT] used + to contain adjacency information within the LSP. + + This document creates the following TLVs and sub-TLVs within the IIH + and LSP PDUs MT TLVs as described below. The '*' indicates new IANA + assignments (per this document). Other entries are shown to provide + context only. + + The MT-Capability TLV is the only TLV that required a new sub- + registry. Type value 144 has been assigned, with a starting sub-TLV + value of 1, and managed by Expert Review. + + + + +Fedyk, et al. Standards Track [Page 34] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + + +-----+----+-----------------+--------+------+-------------+ + | PDU |TLV | SUB-TLV | TYPE | TYPE | #OCCURRENCE | + +-----+----+-----------------+--------+------+-------------+ + IIH + MT-Port-Cap 143 + * SPB-MCID 4 1 + * SPB-Digest 5 >=0 + * SPB-B-VID 6 1 + + LSP + * MT-Capability 144 >=1 + * SPB-Inst 1 1 + * SPB-I-OALG 2 >=0 + * SPBM-SI 3 >=0 + * SPBV-ADDR 4 >=0 + + MT-ISN 222 + or Extended IS Reachability 22 + * SPB-Metric 29 1 + * SPB-A-OALG 30 >=0 + +19. References + +19.1. Normative References + + [802.1aq] "Standard for Local and Metropolitan Area Networks: + Virtual Bridges and Virtual Bridged Local Area Networks - + Amendment 9: Shortest Path Bridging", IEEE P802.1aq, Draft + 4.6, 2012. + + [IS-IS] ISO/IEC 10589:2002, Second Edition, "Intermediate System + to Intermediate System Intra-Domain Routing Exchange + Protocol for use in Conjunction with the Protocol for + Providing the Connectionless-mode Network Service (ISO + 8473)", 2002. + + [MT] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi + Topology (MT) Routing in Intermediate System to + Intermediate Systems (IS-ISs)", RFC 5120, February 2008. + + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. + + [RFC6165] Banerjee, A. and D. Ward, "Extensions to IS-IS for Layer-2 + Systems", RFC 6165, April 2011. + + [RFC6328] Eastlake 3rd, D., "IANA Considerations for Network Layer + Protocol Identifiers", BCP 164, RFC 6328, July 2011. + + + +Fedyk, et al. Standards Track [Page 35] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + +19.2. Informative References + + [802.1ag] "Standard for Local and Metropolitan Area Networks / + Virtual Bridged Local Area Networks / Amendment 5: + Connectivity Fault Management", IEEE STD 802.1ag, 2007. + + [MMRP] "Standard for Local and Metropolitan Area Networks Virtual + Bridged Local Area Networks - Amendment 07: Multiple + Registration Protocol", IEEE STD 802.1ak, 2007. + + [PB] "Standard for Local and Metropolitan Area Networks / + Virtual Bridged Local Area Networks / Amendment 4: + Provider Bridges", IEEE STD 802.1ad, 2005. + + [PBB] "Standard for Local and Metropolitan Area Networks / + Virtual Bridged Local Area Networks / Amendment 7: + Provider Backbone Bridges", IEEE STD 802.1ah, 2008. + + [RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet + Denial-of-Service Considerations", RFC 4732, December + 2006. + + [Y.1731] ITU-T, "OAM Functions and Mechanisms for Ethernet based + networks", ITU-T Y.1731, 2006. + +20. Acknowledgments + + The authors would like to thank Ayan Banerjee, Mick Seaman, Janos + Farkas, Les Ginsberg, Stewart Bryant , Donald Eastlake, Matthew Bocci + and Mike Shand for contributions and/or detailed review. + + + + + + + + + + + + + + + + + + + + + +Fedyk, et al. Standards Track [Page 36] + +RFC 6329 IS-IS Support of IEEE 802.1aq April 2012 + + +Authors' Addresses + + Don Fedyk (editor) + Alcatel-Lucent + Groton, MA 01450 + USA + EMail: Donald.Fedyk@alcatel-lucent.com + + Peter Ashwood-Smith (editor) + Huawei Technologies Canada Ltd. + 303 Terry Fox Drive, Suite 400 + Kanata, Ontario, K2K 3J1 + CANADA + EMail: Peter.AshwoodSmith@huawei.com + + Dave Allan + Ericsson + 300 Holger Way + San Jose, CA 95134 + USA + EMail: david.i.allan@ericsson.com + + Nigel Bragg + Ciena Limited + Ciena House + 43-51 Worship Street + London EC2A 2DX + UK + EMail: nbragg@ciena.com + + Paul Unbehagen + Avaya + 8742 Lucent Boulevard + Highlands Ranch, CO 80129 + USA + EMail: unbehagen@avaya.com + + + + + + + + + + + + + + + +Fedyk, et al. Standards Track [Page 37] + |