idnits 2.17.1 draft-zch-lsr-isis-network-slicing-05.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The abstract seems to contain references ([I-D.nsdt-teas-ns-framework]), which it shouldn't. Please replace those with straight textual mentions of the documents in question. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == Using lowercase 'not' together with uppercase 'MUST', 'SHALL', 'SHOULD', or 'RECOMMENDED' is not an accepted usage according to RFC 2119. Please use uppercase 'NOT' together with RFC 2119 keywords (if that is what you mean). Found 'MUST not' in this paragraph: Note that[I-D.ietf-lsr-flex-algo].also allows user to define other algorithm values, i.e., FA-id within [128, 255], for the purpose of constraint based path computation. However, an FA-id algorithm value MUST not be set in this field, the reason is that FA-id has not semantic local within AII. -- The document date (July 09, 2020) is 1358 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Looks like a reference, but probably isn't: '128' on line 276 -- Looks like a reference, but probably isn't: '255' on line 276 == Unused Reference: 'I-D.nsdt-teas-transport-slice-definition' is defined on line 481, but no explicit reference was found in the text == Unused Reference: 'RFC2119' is defined on line 487, but no explicit reference was found in the text == Outdated reference: A later version (-26) exists of draft-ietf-lsr-flex-algo-07 == Outdated reference: A later version (-05) exists of draft-nsdt-teas-ns-framework-03 ** Downref: Normative reference to an Informational draft: draft-nsdt-teas-ns-framework (ref. 'I-D.nsdt-teas-ns-framework') == Outdated reference: A later version (-04) exists of draft-nsdt-teas-transport-slice-definition-02 ** Downref: Normative reference to an Informational draft: draft-nsdt-teas-transport-slice-definition (ref. 'I-D.nsdt-teas-transport-slice-definition') ** Obsolete normative reference: RFC 5316 (Obsoleted by RFC 9346) == Outdated reference: A later version (-04) exists of draft-peng-teas-network-slicing-03 Summary: 4 errors (**), 0 flaws (~~), 8 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Networking Working Group Y. Zhu 3 Internet-Draft China Telecom 4 Intended status: Standards Track R. Chen 5 Expires: January 10, 2021 S. Peng 6 ZTE Corporation 7 F. Qin 8 China Mobile 9 July 09, 2020 11 IS-IS Extensions to Support Transport Network Slices using Segment 12 Routing 13 draft-zch-lsr-isis-network-slicing-05 15 Abstract 17 [I-D.nsdt-teas-ns-framework] provides a framework of transport 18 slices. 20 This draft describes the IS-IS extensions required to support 21 transport slices using Segment Routing. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at https://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on January 10, 2021. 40 Copyright Notice 42 Copyright (c) 2020 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (https://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 58 2. Conventions used in this document . . . . . . . . . . . . . . 3 59 3. Router Capabilities for TN-slice Identifier . . . . . . . . . 3 60 4. Advertising TN-slice Identifier as a new TE parameter of a 61 link . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 62 5. Advertising TN-slice Identifier for L2 Bundle Member . . . . 5 63 6. Advertising prefix-SID per TN-slice Identifier . . . . . . . 5 64 7. Advertising Adjacency-SID per TN-slice Identifier . . . . . . 7 65 8. Advertising Adjacency-SID per TN-slice Identifier in LANs . . 8 66 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 67 9.1. Router Capabilities for TN-slice Identifier . . . . . . . 9 68 9.2. TN-slice Identifier list sub-TLV . . . . . . . . . . . . 9 69 9.3. L2 Bundle Member TN-slice Identifier sub-TLV . . . . . . 9 70 9.4. Prefix-SID for TN-slice Identifier sub-TLV . . . . . . . 10 71 9.5. Adjacency-SID for TN-slice Identifier sub-TLV . . . . . . 10 72 9.6. LAN-Adj-SID for TN-slice Identifier sub-TLV . . . . . . . 10 73 10. Security Considerations . . . . . . . . . . . . . . . . . . . 10 74 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 75 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 76 12.1. Normative references . . . . . . . . . . . . . . . . . . 10 77 12.2. Informative references . . . . . . . . . . . . . . . . . 12 78 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 80 1. Introduction 82 [I-D.nsdt-teas-ns-framework] provides a framework for discussing 83 transport slices. 85 For a Transport Network, transport network slicing requires the 86 underlying network to support partitioning of the network resources 87 to provide the client with dedicated (private) networking, computing, 88 and storage resources drawn from a shared pool. 89 [I-D.peng-teas-network-slicing] defines a unified TN-slice identifier 90 to indicate the topology, computing, storage resources of the 91 dedicated virtual network for both intra-domain and inter-domain 92 network slicing scenarios, and how to compute SR-BE or SR-TE path 93 according to TN-slice Identifier combined with other creteria. 95 This draft describes the IS-IS extensions required to distribute TN- 96 slice Identifier(that is AII in this draft) information in an AS. 98 2. Conventions used in this document 100 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 101 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 102 document are to be interpreted as described in RFC2119. 104 3. Router Capabilities for TN-slice Identifier 106 Although a router can deduce which TN-slices it has participated in 107 according to the AII(administrative instance identifier) 108 configuration of all links, an ISIS instance can explicitly control 109 which TN-slices it wants to enable (or join), to explicitly control 110 which SPT (shortest path tree) for a specific AII to be created. It 111 is possible for a route process not to join any TN-slices (except the 112 default AII 0) in despite of any AII configuration of any links. 113 Especially, it is hard to deduce the participated TN-slice according 114 to the AII configuration of L2 Bundle Member. 116 This section defines AII Participation sub-TLV which is inserted into 117 the IS-IS Router Capability TLV-242 that is defined in [RFC7981], to 118 explicitly advertise which TN-slice a router wants to take part in. 120 The TN-slice identifier Participation sub-TLV has the following 121 format: 123 0 1 2 3 124 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 1 125 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 126 | Type=TBD1 | Length | Number | | 127 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 128 | AII for virtual networks 1 | 129 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 130 | ...... | 131 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 132 | AII for virtual networks N | 133 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 135 Figure 1 137 where: 139 Type: TBD1 (Suggested value to be assigned by IANA) 141 Length: variable. 143 Number:Number of virtual networks. 145 AII for VN: allocate different TN-slice identifier (AII) for 146 different virtual networks. AII is used to distinguish different 147 virtual network resources. 149 4. Advertising TN-slice Identifier as a new TE parameter of a link 151 [RFC5305] describes extensions to the Intermediate System to 152 Intermediate System (IS-IS) protocol to support Traffic Engineering 153 (TE). 155 TN-slice Identifier can be used to color links to partition underlay 156 resource. This document defines a new extension of the existing IGP- 157 TE mechanisms[RFC5305] to distribute TN-slice Identifier information 158 in an AS as a new TE parameter of a link. 160 The TN-slice Identifier list sub-TLV has the following format: 162 0 1 2 3 163 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 1 164 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 165 | Type=TBD2 | Length | Reserved | Number | 166 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 167 | AII for virtual networks 1 | 168 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 169 | ...... | 170 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 171 | AII for virtual networks N | 172 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 174 Figure 2 176 Type: TBD2 (Suggested value to be assigned by IANA) 178 Length: variable. 180 Number:Number of virtual networks. 182 AII for VN: allocate different TN-slice identifier (AII) for 183 different virtual networks. AII is used to distinguish different 184 virtual network resources. 186 This sub-TLV MAY be present in any of the following TLVs: 188 TLV-22 (Extended IS reachability) [RFC5305]. 190 TLV-222 (Multitopology IS)[RFC5120]. 192 TLV-23 (IS Neighbor Attribute)[RFC5311]. 194 TLV-223 (Multitopology IS Neighbor Attribute)[RFC5311]. 196 TLV-141 (inter-AS reachability information)[RFC5316]. 198 This sub-TLV SHOULD appear once at most in each TLV. Indicates that 199 a link MAY belong to multiple virtual networks. 201 Note that AII 0 does not require notification, and all links are 202 always in AII 0 at the same time. 204 5. Advertising TN-slice Identifier for L2 Bundle Member 206 [RFC8668] defines a sub-TLV of L2 Bundle Attribute Descriptors, and 207 the sub-TLV may define an attribute common to all of the bundle 208 members listed or a sub-TLV may define an attribute unique to each 209 bundle member. This document defines a new sub-TLV: L2 Bundle Member 210 TN-slice Identifier sub-TLV. 212 This sub-TLV is used to advertise TN-slice Identifier for L2 Bundle 213 Member associated with a parent L3 adjacency which is Point-to- 214 Point.The following format is defined for this sub-TLV: 216 Type: TBD3. 218 Length: variable 220 L2 Bundle Member TN-slice Identifier.There MUST be one TN-slice 221 Identifier(AII) for each of the L2 Bundle Members advertised under 222 the preceding L2 Bundle Member Attribute Descriptor. 224 This sub-TLV MAY be present in the following TLVs: 226 TLV-25 (L2 Bundle Member Attributes) [RFC8668]. 228 This sub-TLV SHOULD appear once at most in the TLV. Indicates that 229 the TN-slice Identifier for L2 Bundle Member. 231 6. Advertising prefix-SID per TN-slice Identifier 233 [RFC8667] defines a new IS-IS sub-TLV: the Prefix Segment Identifier 234 sub-TLV (Prefix-SID sub-TLV). The Prefix-SID sub-TLV carries the 235 Segment Routing IGP-Prefix-SID as defined in [RFC8402], and is 236 associated to a prefix advertised by a node. 238 To distinguish forwarding behavior of different virtual networks, 239 Prefix-SID need to be allocated per TN-slice Identifier and 240 advertised in the IGP domain. This document defines a new extension 241 of the existing Prefix-SID sub-TLV. 243 The Prefix-SID for TN-slice Identifier sub-TLV has the following 244 format: 246 0 1 2 3 247 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 1 248 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 249 | Type=TBD4 | Length | Flag | Algorithm | 250 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 251 | AII | 252 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 253 | SID/Index/Label(Variable) | 254 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 256 Figure 3 258 where: 260 Type:TBD4 (Suggested value to be assigned by IANA) 262 Length: Variable. Depending on the size of the SID. 264 The "Flags" and "SID/Index/Label" fields are the same as the Prefix- 265 SID sub-TLV [RFC8667] . 267 Algorithm: Accoridng to section "3.2. SR-Algorithm Sub-TLV" of 268 [RFC8667] , two values can be set in this field. 270 o 0: Shortest Path First (SPF) algorithm based on link metric. 272 o 1: Strict Shortest Path First (SPF) algorithm based on link 273 metric. 275 Note that[I-D.ietf-lsr-flex-algo].also allows user to define other 276 algorithm values, i.e., FA-id within [128, 255], for the purpose of 277 constraint based path computation. However, an FA-id algorithm value 278 MUST not be set in this field, the reason is that FA-id has not 279 semantic local within AII. 281 AII: Identifies the TN-slice (AII) information corresponding to the 282 Prefix-SID. 284 This sub-TLV MAY be present in any of the following TLVs: 286 TLV-135 (Extended IPv4 reachability) defined in [RFC5305]. 288 TLV-235 (Multitopology IPv4 Reachability) defined in [RFC5120]. 290 TLV-236 (IPv6 IP Reachability) defined in [RFC5308]. 292 TLV-237 (Multitopology IPv6 IP Reachability) defined in [RFC5120]. 294 This sub-TLV MAY appear multiple times in each TLV. 296 7. Advertising Adjacency-SID per TN-slice Identifier 298 [RFC8667] defines the IS-IS sub-TLV: the Adjacency Segment Identifier 299 sub-TLV (Adj-SID sub-TLV).The Adj-SID sub-TLV is an optional sub-TLV 300 carrying the Segment Routing IGP-Adjacency-SID as defined in 301 [RFC8402]. 303 To distinguish forwarding behavior of different virtual networks, 304 Adjacency-SID need to be allocated per TN-slice Identifier and 305 advertised in the IGP domain. This document defines a new extension 306 of the existing Adjacency-SID sub-TLV. 308 The Adjacency-SID for TN-slice Identifier sub-TLV has the following 309 format: 311 0 1 2 3 312 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 1 313 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 314 | Type=TBD5 | Length | Flag | Algorithm | 315 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 316 | AII | 317 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 318 | SID/Index/Label(Variable) | 319 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 321 Figure 4 323 where: 325 Type:TBD5(Suggested value to be assigned by IANA) 327 Length: Variable. Depending on the size of the SID. 329 The "Flags" and "SID/Index/Label" fields are the same as the 330 Adjacency-SID sub-TLV [RFC8667]. 332 AII: Identifies the TN-slice (AII) information corresponding to the 333 Adjacency-SID. 335 This sub-TLV MAY be present in any of the following TLVs: 337 TLV-22 (Extended IS reachability) [RFC5305]. 339 TLV-222 (Multitopology IS)[RFC5120]. 341 TLV-23 (IS Neighbor Attribute)[RFC5311]. 343 TLV-223 (Multitopology IS Neighbor Attribute)[RFC5311]. 345 TLV-141 (inter-AS reachability information)[RFC5316]. 347 Multiple Adj-SID sub-TLVs MAY be associated with a single IS- 348 neighbor. This sub-TLV MAY appear multiple times in each TLV. 350 8. Advertising Adjacency-SID per TN-slice Identifier in LANs 352 In LAN subnetworks,[RFC8667] defines the LAN-Adj-SID sub-TLV for a 353 router to advertise the Adj-SID of each of its neighbors. 355 To distinguish forwarding behavior of different virtual networks, 356 Adjacency-SID need to be allocated per TN-slice Identifier and 357 advertised in the IGP domain. This document defines a new extension 358 of the existing Adjacency-SID sub-TLV. 360 The LAN-Adj-SID for TN-slice Identifier sub-TLV has the following 361 format: 363 0 1 2 3 364 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 1 365 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 366 | Type=TBD6 | Length | Flags | Weight | 367 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 369 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 370 | Neighbor System-ID (ID length octets) | 371 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 372 | | 373 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 374 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 375 | AII | 376 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 377 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 378 | SID/Label/Index (variable) | 379 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 381 Figure 5 383 where: 385 Type:TBD6 (Suggested value to be assigned by IANA) 387 Length: Variable. Depending on the size of the SID. 389 The "Flags" and "SID/Index/Label" fields are the same as the 390 Adjacency-SID sub-TLV [RFC8667]. 392 AII: Identifies the TN-slice (AII) information corresponding to the 393 Adjacency-SID. 395 This sub-TLV MAY be present in any of the following TLVs: 397 TLV-22 (Extended IS reachability) [RFC5305]. 399 TLV-222 (Multitopology IS)[RFC5120]. 401 TLV-23 (IS Neighbor Attribute)[RFC5311]. 403 TLV-223 (Multitopology IS Neighbor Attribute)[RFC5311]. 405 Multiple Adj-SID sub-TLVs MAY be associated with a single IS- 406 neighbor. This sub-TLV MAY appear multiple times in each TLV. 408 9. IANA Considerations 410 This document requests allocation for the following Sub-TLVs. 412 9.1. Router Capabilities for TN-slice Identifier 414 This document requests IANA to assign a new code point in the "sub- 415 TLV for TLV 242" registry. 417 Type: TBD1 419 9.2. TN-slice Identifier list sub-TLV 421 This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 22, 422 222, 23,223 and 141 registry". 424 Type:TBD2(to be assigned by IANA). 426 9.3. L2 Bundle Member TN-slice Identifier sub-TLV 428 This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 22, 429 222, 23, 25, 223 and 141 registry. 431 Type:TBD3(to be assigned by IANA). 433 This sub-TLV is allowed in the following TLVs: 435 22 23 25 141 222 223 436 n n y n n n 438 9.4. Prefix-SID for TN-slice Identifier sub-TLV 440 This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 441 135,235,226 and 237 registry". 443 Type:TBD4(to be assigned by IANA). 445 9.5. Adjacency-SID for TN-slice Identifier sub-TLV 447 This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 22, 448 222, 23,223 and 141 registry". 450 Type:TBD5(to be assigned by IANA). 452 9.6. LAN-Adj-SID for TN-slice Identifier sub-TLV 454 This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 22, 455 222, 23, and 223registry". 457 Type:TBD6(to be assigned by IANA). 459 10. Security Considerations 461 TBD. 463 11. Acknowledgements 465 TBD. 467 12. References 469 12.1. Normative references 471 [I-D.ietf-lsr-flex-algo] 472 Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and 473 A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex- 474 algo-07 (work in progress), April 2020. 476 [I-D.nsdt-teas-ns-framework] 477 Gray, E. and J. Drake, "Framework for Transport Network 478 Slices", draft-nsdt-teas-ns-framework-03 (work in 479 progress), April 2020. 481 [I-D.nsdt-teas-transport-slice-definition] 482 Rokui, R., Homma, S., Makhijani, K., and L. Contreras, 483 "IETF Definition of Transport Slice", draft-nsdt-teas- 484 transport-slice-definition-02 (work in progress), April 485 2020. 487 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 488 Requirement Levels", BCP 14, RFC 2119, 489 DOI 10.17487/RFC2119, March 1997, 490 . 492 [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi 493 Topology (MT) Routing in Intermediate System to 494 Intermediate Systems (IS-ISs)", RFC 5120, 495 DOI 10.17487/RFC5120, February 2008, 496 . 498 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 499 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 500 2008, . 502 [RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308, 503 DOI 10.17487/RFC5308, October 2008, 504 . 506 [RFC5311] McPherson, D., Ed., Ginsberg, L., Previdi, S., and M. 507 Shand, "Simplified Extension of Link State PDU (LSP) Space 508 for IS-IS", RFC 5311, DOI 10.17487/RFC5311, February 2009, 509 . 511 [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in 512 Support of Inter-Autonomous System (AS) MPLS and GMPLS 513 Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316, 514 December 2008, . 516 [RFC7981] Ginsberg, L., Previdi, S., and M. Chen, "IS-IS Extensions 517 for Advertising Router Information", RFC 7981, 518 DOI 10.17487/RFC7981, October 2016, 519 . 521 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 522 Decraene, B., Litkowski, S., and R. Shakir, "Segment 523 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 524 July 2018, . 526 [RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C., 527 Bashandy, A., Gredler, H., and B. Decraene, "IS-IS 528 Extensions for Segment Routing", RFC 8667, 529 DOI 10.17487/RFC8667, December 2019, 530 . 532 [RFC8668] Ginsberg, L., Ed., Bashandy, A., Filsfils, C., Nanduri, 533 M., and E. Aries, "Advertising Layer 2 Bundle Member Link 534 Attributes in IS-IS", RFC 8668, DOI 10.17487/RFC8668, 535 December 2019, . 537 12.2. Informative references 539 [I-D.peng-teas-network-slicing] 540 Peng, S., Chen, R., Mirsky, G., and F. Qin, "Packet 541 Network Slicing using Segment Routing", draft-peng-teas- 542 network-slicing-03 (work in progress), February 2020. 544 Authors' Addresses 546 Yongqing Zhu 547 China Telecom 549 Email: zhuyq.gd@chinatelecom.cn 551 Ran Chen 552 ZTE Corporation 554 Email: chen.ran@zte.com.cn 556 Shaofu Peng 557 ZTE Corporation 559 Email: peng.shaofu@zte.com.cn 561 Fengwei Qin 562 China Mobile 564 Email: qinfengwei@chinamobile.com