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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 LSR Routing Working Group J. Dong 3 Internet-Draft Z. Hu 4 Intended status: Standards Track Huawei Technologies 5 Expires: August 24, 2021 February 20, 2021 7 Advertising SRv6 SIDs for Layer 2 Bundle Member Links in IGP 8 draft-dong-lsr-l2bundle-srv6-00 10 Abstract 12 There are deployments where the Layer-3 interface on which IGP 13 operates is a Layer-2 interface bundle. Existing IGP advertisements 14 only support advertising link attributes of the Layer-3 interface. 15 If entities external to IGP wish to control traffic flows on the 16 individual physical links that comprise the Layer-2 interface bundle, 17 link attribute information about the bundle members is advertised by 18 IGP extensions for Layer-2 (L2) bundle. 20 When Segment Routing over IPv6 (SRv6) is used with Layer-2 interface 21 bundle to control traffic flows on the individual member links, the 22 SRv6 SIDs which represent the Layer 2 member links of the L2 bundle 23 needs to be advertised in IGP. 25 This document proposes the IGP extensions to advertise the SRv6 SIDs 26 of the Layer 2 (L2) bundle member links. 28 Requirements Language 30 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 31 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 32 document are to be interpreted as described in RFC 2119 [RFC2119]. 34 Status of This Memo 36 This Internet-Draft is submitted in full conformance with the 37 provisions of BCP 78 and BCP 79. 39 Internet-Drafts are working documents of the Internet Engineering 40 Task Force (IETF). Note that other groups may also distribute 41 working documents as Internet-Drafts. The list of current Internet- 42 Drafts is at https://datatracker.ietf.org/drafts/current/. 44 Internet-Drafts are draft documents valid for a maximum of six months 45 and may be updated, replaced, or obsoleted by other documents at any 46 time. It is inappropriate to use Internet-Drafts as reference 47 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on August 24, 2021. 50 Copyright Notice 52 Copyright (c) 2021 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents 57 (https://trustee.ietf.org/license-info) in effect on the date of 58 publication of this document. Please review these documents 59 carefully, as they describe your rights and restrictions with respect 60 to this document. Code Components extracted from this document must 61 include Simplified BSD License text as described in Section 4.e of 62 the Trust Legal Provisions and are provided without warranty as 63 described in the Simplified BSD License. 65 Table of Contents 67 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 68 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 69 3. SRv6 Function for L2 Bundle Member Links . . . . . . . . . . 3 70 4. Advertising SRv6 SIDs for L2 Bundle Members . . . . . . . . . 3 71 4.1. SRv6 SIDs Encodings for IS-IS L2 Bundle . . . . . . . . . 3 72 4.1.1. L2 Bundle Member SRv6 End.XU SID Sub-TLV . . . . . . 4 73 4.1.2. L2 Bundle Member SRv6 LAN End.XU SID Sub-TLV . . . . 5 74 4.2. SRv6 SIDs Encodings for OSPF L2 Bundle . . . . . . . . . 6 75 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 76 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7 77 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 78 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 79 8.1. Normative References . . . . . . . . . . . . . . . . . . 7 80 8.2. Informative References . . . . . . . . . . . . . . . . . 8 81 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 83 1. Introduction 85 There are deployments where the Layer-3 interface on which an IGP 86 adjacency is established is a Layer-2 interface bundle, for instance, 87 a Link Aggregation Group (LAG) [IEEE802.1AX]. This reduces the 88 number of adjacencies that need to be maintained by the routing 89 protocol in cases where there are parallel links between the 90 neighbors. Entities external to IS-IS such as Path Computation 91 Elements (PCEs) [RFC4655] may wish to control traffic flows on 92 individual members of the underlying Layer-2 bundle. In order to do 93 so, link attribute information about individual bundle members is 94 required. 96 [RFC8668] and [I-D.ietf-lsr-ospf-l2bundles] specify the IGP 97 extensions to advertise link attribute information for each of the L2 98 Bundle members which comprise the Layer-3 interface, in which the 99 encoding and advertisement of SR-MPLS adjacency SIDs of each bundle 100 member link is defined. When SRv6 is used with Layer-2 interface 101 bundle, to control traffic flows on the individual member links, the 102 SRv6 SIDs which represent the Layer-2 member links of the L2 bundle 103 needs to be advertised. 105 This document proposes the IGP extensions to advertise the SRv6 SIDs 106 of the Layer-2 (L2) bundle member links. 108 2. Requirements Language 110 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 111 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 112 "OPTIONAL" in this document are to be interpreted as described in 113 BCP14 RFC 2119 [RFC2119] RFC 8174 [RFC8174] when, and only when, they 114 appear in all capitals, as shown here. 116 3. SRv6 Function for L2 Bundle Member Links 118 As defined in [I-D.ietf-spring-srv6-network-programming], the SRv6 119 End.X behavior means "Endpoint with cross-connect to an array of 120 layer-3 adjacencies". An SRv6 SID associated with a Layer 2 bundle 121 member link of an L3 adjacency is considered a variant of the End.X 122 behavior. In order to distinguish it from the SIDs associated with a 123 L3 adjacency, it is considered that a different type of SRv6 function 124 needs to be used. 126 [I-D.dong-spring-srv6-inter-layer-programming] defines a new End.XU 127 function which means "Endpoint with cross-connect to an underlay 128 interface", this function can be used for the L2 bundle member links. 130 4. Advertising SRv6 SIDs for L2 Bundle Members 132 4.1. SRv6 SIDs Encodings for IS-IS L2 Bundle 134 This section defines the IS-IS sub-TLVs to advertise SRv6 SIDs for L2 135 Bundle Members. Following the encoding mechanism used in [RFC8668] 136 for the advertisement of SR-MPLS adj-SIDs for L2 Bundle Members, this 137 allows the advertisement of a set of SRv6 SIDs (one per L2 Bundle 138 Member) in a single sub-TLV. 140 4.1.1. L2 Bundle Member SRv6 End.XU SID Sub-TLV 142 [I-D.ietf-lsr-isis-srv6-extensions] defines the SRv6 End.X SID sub- 143 TLV to advertise an SRv6 SID associated with a point to point 144 adjacency. This document defines a new sub-TLV of called "L2 Bundle 145 Member SRv6 End.XU SIDs" to advertise the SRv6 End.XU SIDs for the L2 146 Bundle Members. This sub-TLV is allowed to be carried in TLV 25 "L2 147 Bundle Member Attributes" only. The format of the sub-TLV is as 148 below: 150 0 1 2 3 151 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 1 152 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 153 | Type | Length | 154 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 155 | Flags | Algorithm | Weight | 156 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 157 | Endpoint Behavior | 158 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 159 | SID #1 (128 bits) | 160 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 161 | SID #2 (128 bits) | 162 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 163 | ... | 164 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 165 | SID #n (128 bits) | 166 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 167 |Sub-sub-tlv-len| Sub-sub-TLVs (variable) . . . | 168 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 170 Where: 172 o Type: TBA. 174 o Length: Variable. 176 o Flags: 1 octet. The format is the same as the Flags field in the 177 SRv6 End.X SID sub-TLV as defined in 178 [I-D.ietf-lsr-isis-srv6-extensions]. 180 o Algorithm: 1 octet. The algorithm values are defined in the IGP 181 Algorithm Type registry. 183 o Weight: 1 octet. The value represents the weight of the SID for 184 the purpose of load balancing. 186 o Endpoint Behavior: 2 octets. It SHOULD be set to the Endpoint 187 functions as defined in 188 [I-D.dong-spring-srv6-inter-layer-programming]. 190 o SIDs. One or multiple 16-octet SRv6 SIDs. The number of the SIDs 191 is determined by the "Number of L2 Bundle Member Descriptors" 192 field as defined in [RFC8668]. 194 o Sub-sub-tlv-length: 1 octet. Number of octets used by sub-sub- 195 TLVs. 197 4.1.2. L2 Bundle Member SRv6 LAN End.XU SID Sub-TLV 199 [I-D.ietf-lsr-isis-srv6-extensions] defines the SRv6 LAN End.X SID 200 sub-TLV to advertise an SRv6 SID associated with a LAN adjacency. 201 This document defines a new sub-TLV called "L2 Bundle Member SRv6 LAN 202 End.XU SIDs" to advertise the SRv6 LAN End.XU SIDs for the L2 Bundle 203 Members. The format of the sub-TLV is as below: 205 0 1 2 3 206 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 1 207 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 208 | Type | Length | | 209 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 210 | Neighbor System-ID (ID length octets) | 211 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 212 | Flags | Algorithm | Weight | 213 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 214 | Endpoint Behavior | 215 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 216 | SID #1 (128 bits) | 217 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 218 | SID #2 (128 bits) | 219 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 220 | ... | 221 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 222 | SID #n (128 bits) | 223 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 224 |Sub-sub-tlv-len| Sub-sub-TLVs (variable) . . . | 225 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 227 Where: 229 o Type: TBA. 231 o Length: Variable. 233 o Neighbor System-ID: IS-IS System-ID of length "ID Length" as 234 defined in [ISO10589]. 236 o Flags: 1 octet, the format is the same as the Flags field in the 237 SRv6 End.X SID sub-TLV as defined in 238 [I-D.ietf-lsr-isis-srv6-extensions]. 240 o Algorithm: 1 octet. The algorithm values are defined in the IGP 241 Algorithm Type registry. 243 o Weight: 1 octet. The value represents the weight of the End.X SID 244 for the purpose of load balancing. 246 o Endpoint Behavior: 2 octets. It SHOULD be set to the Endpoint 247 functions as defined in 248 [I-D.dong-spring-srv6-inter-layer-programming]. 250 o SIDs. One or multiple 16-octet SRv6 SIDs. The number of the SIDs 251 is determined by the "Number of L2 Bundle Member Descriptors" 252 field as defined in [RFC8668]. 254 o Sub-sub-tlv-length: 1 octet. Number of octets used by sub-sub- 255 TLVs. 257 4.2. SRv6 SIDs Encodings for OSPF L2 Bundle 259 This section defines the mechanism to advertise SRv6 SIDs for L2 260 Bundle Members. In [I-D.ietf-lsr-ospf-l2bundles], the SR-MPLS 261 Adjacency SID sub-TLVs for the L3 adjacency is reused for the 262 advertisement of Adjacency SIDs of L2 Bundle Members. For SRv6 data 263 plane , the SRv6 End.X SID sub-TLV and SRv6 LAN End.X SID Sub-TLV as 264 defined in [I-D.ietf-lsr-ospfv3-srv6-extensions] are reused for the 265 advertisement of SRv6 End.XU SIDs of L2 Bundle Members, the Endpoint 266 Behavior in the sub-TLV SHOULD be set to the Endpoint functions as 267 defined in [I-D.dong-spring-srv6-inter-layer-programming]. 269 5. IANA Considerations 271 IANA is requested to assign two new code points from the IS-IS "Sub- 272 TLVs for TLVs 22, 23, 25, 141, 222, and 223" registry. 274 +------+--------------------------+----+----+----+-----+-----+-----+ 275 | Type | Description | 22 | 23 | 25 | 141 | 222 | 223 | 276 +======+==========================+====+====+====+=====+=====+=====+ 277 | TBD | L2 Bundle Member SRv6 | n | n | y | n | n | n | 278 | | End.XU SID | | | | | | | 279 +------+--------------------------+----+----+----+-----+-----+-----+ 280 | TBD | L2 Bundle Member SRv6 | n | n | y | n | n | n | 281 | | LAN End.XU SID | | | | | | | 282 +------+--------------------------+----+----+----+-----+-----+-----+ 284 6. Security Considerations 286 The security considerations in [RFC8668] and 287 [I-D.ietf-lsr-ospf-l2bundles] apply. This document introduces no 288 additional security vulnerabilities to IS-IS and OSPF. 290 7. Acknowledgements 292 The authors would like to thank Zhenbin Li for the review and 293 discussion of this document. 295 8. References 297 8.1. Normative References 299 [I-D.ietf-lsr-isis-srv6-extensions] 300 Psenak, P., Filsfils, C., Bashandy, A., Decraene, B., and 301 Z. Hu, "IS-IS Extension to Support Segment Routing over 302 IPv6 Dataplane", draft-ietf-lsr-isis-srv6-extensions-11 303 (work in progress), October 2020. 305 [I-D.ietf-lsr-ospf-l2bundles] 306 Talaulikar, K. and P. Psenak, "Advertising L2 Bundle 307 Member Link Attributes in OSPF", draft-ietf-lsr-ospf- 308 l2bundles-00 (work in progress), October 2020. 310 [I-D.ietf-lsr-ospfv3-srv6-extensions] 311 Li, Z., Hu, Z., Cheng, D., Talaulikar, K., and P. Psenak, 312 "OSPFv3 Extensions for SRv6", draft-ietf-lsr- 313 ospfv3-srv6-extensions-01 (work in progress), August 2020. 315 [IEEE802.1AX] 316 IEEE, "IEEE Standard for Local and metropolitan area 317 networks -- Link Aggregation", 2016, 318 . 320 [ISO10589] 321 ISO, "Information technology -- Telecommunications and 322 information exchange between systems -- Intermediate 323 System to Intermediate System intra-domain routing 324 information exchange protocol for use in conjunction with 325 the protocol for providing the connectionless-mode network 326 service (ISO 8473)", November 2002, 327 . 329 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 330 Requirement Levels", BCP 14, RFC 2119, 331 DOI 10.17487/RFC2119, March 1997, 332 . 334 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 335 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 336 May 2017, . 338 [RFC8668] Ginsberg, L., Ed., Bashandy, A., Filsfils, C., Nanduri, 339 M., and E. Aries, "Advertising Layer 2 Bundle Member Link 340 Attributes in IS-IS", RFC 8668, DOI 10.17487/RFC8668, 341 December 2019, . 343 8.2. Informative References 345 [I-D.dong-spring-srv6-inter-layer-programming] 346 Dong, J. and Z. Du, "SRv6 for Inter-Layer Network 347 Programming", draft-dong-spring-srv6-inter-layer- 348 programming-01 (work in progress), October 2020. 350 [I-D.ietf-spring-srv6-network-programming] 351 Filsfils, C., Camarillo, P., Leddy, J., Voyer, D., 352 Matsushima, S., and Z. Li, "SRv6 Network Programming", 353 draft-ietf-spring-srv6-network-programming-28 (work in 354 progress), December 2020. 356 [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation 357 Element (PCE)-Based Architecture", RFC 4655, 358 DOI 10.17487/RFC4655, August 2006, 359 . 361 Authors' Addresses 362 Jie Dong 363 Huawei Technologies 364 Huawei Campus, No. 156 Beiqing Road 365 Beijing 100095 366 China 368 Email: jie.dong@huawei.com 370 Zhibo Hu 371 Huawei Technologies 372 Huawei Campus, No. 156 Beiqing Road 373 Beijing 100095 374 China 376 Email: huzhibo@huawei.com