idnits 2.17.1 draft-ietf-idr-bgpls-inter-as-topology-ext-07.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 : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (September 30, 2019) is 1664 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) ** Obsolete normative reference: RFC 5316 (Obsoleted by RFC 9346) ** Obsolete normative reference: RFC 7752 (Obsoleted by RFC 9552) == Outdated reference: A later version (-12) exists of draft-ietf-teas-native-ip-scenarios-09 Summary: 2 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IDR Working Group A. Wang 3 Internet-Draft China Telecom 4 Intended status: Standards Track H. Chen 5 Expires: April 2, 2020 Futurewei 6 K. Talaulikar 7 Cisco Systems 8 S. Zhuang 9 Huawei Technologies 10 S. Ma 11 Mellanox Technologies 12 September 30, 2019 14 BGP-LS Extension for Inter-AS Topology Retrieval 15 draft-ietf-idr-bgpls-inter-as-topology-ext-07 17 Abstract 19 This document describes the process to build Border Gateway Protocol- 20 Link State (BGP-LS) key parameters in inter-domain scenario, defines 21 one new BGP-LS Network Layer Reachability Information (NLRI) type 22 (Stub Link NLRI) and some new inter Autonomous (inter-AS) Traffic 23 Engineering (TE) related Type-Length-Values (TLVs) for BGP-LS to let 24 Software Definition Network (SDN) controller retrieve the network 25 topology automatically under various inter-AS environments. 27 Such extension and process can enable the network operator to collect 28 the interconnect information between different domains and then 29 calculate the overall network topology automatically based on the 30 information provided by BGP-LS protocol. 32 Status of This Memo 34 This Internet-Draft is submitted in full conformance with the 35 provisions of BCP 78 and BCP 79. 37 Internet-Drafts are working documents of the Internet Engineering 38 Task Force (IETF). Note that other groups may also distribute 39 working documents as Internet-Drafts. The list of current Internet- 40 Drafts is at https://datatracker.ietf.org/drafts/current/. 42 Internet-Drafts are draft documents valid for a maximum of six months 43 and may be updated, replaced, or obsoleted by other documents at any 44 time. It is inappropriate to use Internet-Drafts as reference 45 material or to cite them other than as "work in progress." 47 This Internet-Draft will expire on April 2, 2020. 49 Copyright Notice 51 Copyright (c) 2019 IETF Trust and the persons identified as the 52 document authors. All rights reserved. 54 This document is subject to BCP 78 and the IETF Trust's Legal 55 Provisions Relating to IETF Documents 56 (https://trustee.ietf.org/license-info) in effect on the date of 57 publication of this document. Please review these documents 58 carefully, as they describe your rights and restrictions with respect 59 to this document. Code Components extracted from this document must 60 include Simplified BSD License text as described in Section 4.e of 61 the Trust Legal Provisions and are provided without warranty as 62 described in the Simplified BSD License. 64 Table of Contents 66 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 67 2. Conventions used in this document . . . . . . . . . . . . . . 3 68 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 69 4. Inter-AS Domain Scenarios. . . . . . . . . . . . . . . . . . 3 70 5. Stub Link NLRI . . . . . . . . . . . . . . . . . . . . . . . 4 71 5.1. Inter-AS Native IP Scenario . . . . . . . . . . . . . . . 5 72 5.2. Inter-AS TE Scenario . . . . . . . . . . . . . . . . . . 6 73 6. Inter-AS TE NLRI related TLVs . . . . . . . . . . . . . . . . 6 74 6.1. Remote AS Number TLV . . . . . . . . . . . . . . . . . . 7 75 6.2. IPv4 Remote ASBR ID . . . . . . . . . . . . . . . . . . . 7 76 6.3. IPv6 Remote ASBR ID . . . . . . . . . . . . . . . . . . . 8 77 7. Topology Reconstruction. . . . . . . . . . . . . . . . . . . 8 78 8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 79 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 80 9.1. New BGP-LS NLRI type . . . . . . . . . . . . . . . . . . 9 81 9.2. New Link Descriptors . . . . . . . . . . . . . . . . . . 10 82 10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 10 83 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 84 11.1. Normative References . . . . . . . . . . . . . . . . . . 10 85 11.2. Informative References . . . . . . . . . . . . . . . . . 11 86 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 88 1. Introduction 90 BGP-LS [RFC7752] describes the methodology that using BGP protocol to 91 transfer the Link-State information. Such method can enable SDN 92 controller to collect the underlay network topology automatically, 93 but normally it can only get the information within one Interior 94 Gateway Protocol (IGP) domain. If the operator has more than one IGP 95 domain, and these domains interconnect with each other, there is no 96 mechanic within current BGP- LS to transfer the interconnect topology 97 information. 99 Draft [I-D.ietf-idr-bgpls-segment-routing-epe] defines some 100 extensions for exporting BGP peering node topology information 101 (including its peers, interfaces and peering ASs) in a way that is 102 exploitable in order to compute efficient BGP Peering Engineering 103 policies and strategies. Such information can also be used to 104 calculate the interconnection topology among different IGP domains, 105 but it requires every border router to run BGP-LS protocol and report 106 the information to SDN controller. Considering there will be several 107 border routers on the network boundary, such solution restricts its 108 deployment flexibility. 110 This draft analysis the situations that the SDN controller needs to 111 get the interconnected topology information between different AS 112 domains, defines the new Stub Link NLRI and some new TLVs within the 113 BGP-LS protocol to transfer the key information related to them. 114 After that, the SDN controller can then deduce the multi-domain 115 topology automatically based on the information from BGP-LS protocol. 117 2. Conventions used in this document 119 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 120 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 121 document are to be interpreted as described in RFC 2119 [RFC2119] . 123 3. Terminology 125 The following terms are defined in this document: 127 o IDCs: Internet Data Centers 129 o MAN: Metrio-Area-Network 131 o SDN: Software Definition Network 133 4. Inter-AS Domain Scenarios. 135 Figure 1 illustrates the multi-domain scenarios that this draft 136 discusses. Normally, SDN Controller can get the topology of IGP A 137 and IGP B individually via the BGP-LS protocol, but it can't get the 138 topology connection information between these two IGP domains because 139 there is generally no IGP protocol run on the connected links. 141 +-----------------+ 142 +----+IP SDN Controller+----+ 143 | +-----------------+ | 144 | | 145 |BGP-LS |BGP-LS 146 | | 147 +---------------+-----+ +-----+--------------+ 148 | +--+ +-++ ++-+ +-++ +|-+ +--+| 149 | |S1+--------+S2+---+B1+-----------+B2+---+T1+--------+T2|| 150 | +-++ N1 +-++ ++-+ +-++ ++++ N2 +-++| 151 | | | | | || | | 152 | | | | | || | | 153 | +-++ +-++ ++-+ +-++ ++++ +-++| 154 | |S4+--------+S3+---+B3+-----------+B4+---+T3+--------+T4|| 155 | +--+ +--+ ++-+ +-++ ++-+ +--+| 156 | | | | 157 | | | | 158 | IGP A | | IGP B | 159 +---------------------+ +--------------------+ 161 Figure 1: Inter-AS Domain Scenarios 163 5. Stub Link NLRI 165 [RFC7752] defines four NLRI types(Node NLRI, Link NLRI, IPv4 Topology 166 Prefix NLRI, IPv6 Topology Prefix NLRI) to transfer the topology and 167 prefix information. For inter-as link, the two ends of the link 168 locates in different IGP domains, then it is not appropriate to 169 transfer their information within the current defined NLRI types. 171 This draft defines one new NLRI type, called Stub Link NLRI, which is 172 coded as the following format: 174 0 1 2 3 175 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 1 176 +-+-+-+-+-+-+-+-+ 177 | Protocol-ID | 178 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 179 | Identifier | 180 | (64 bits) | 181 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 182 // Local Node Descriptors (variable) // 183 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 184 // Stub Link Descriptors (variable) // 185 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 187 Figure 2: Stub Link NLRI Format 189 The "Protocol-ID" should be set to the value that indicates "Direct" 190 protocol. 192 The semantics of "Local Node Descriptors" and "Stub Link Descriptors" 193 are same as that defined in [RFC7752] for "Node Descriptors" and 194 "Link Descriptor". 196 This newly defined NLRI can be used to describe the link that has 197 only one end located within the IGP domain, as described in the 198 following sections. 200 5.1. Inter-AS Native IP Scenario 202 Draft [I-D.ietf-teas-native-ip-scenarios] describes the situation 203 that operator needs some traffic engineering solution for the inter- 204 as native IP environment. In such situation, different domain may 205 run different IGP protocol. The operator needs to know the inter-as 206 topology first to calculate the end to end optimal path centrally. 208 When IGP A or IGP B in Figure 1 runs native IS-IS/OSPF protocol, the 209 operator can use passive feature for the inter-domain links to let 210 the routers within the IGP domain know these links. Such stub links 211 information can then be carried within the Stub Link NLRI reported 212 via the BGP-LS protocol to the SDN controller. 214 For OSPF, when the interface is configured as passive, the "Linktype" 215 field in corresponding Router LSA will be set to 3, to indicate it 216 connects with stub network. Other routers in the IGP domain can 217 identify such interfaces via this characteristics, and report them 218 via the newly defined "Stub Link NLRI". 220 For ISIS, currently there is no such mechanism to distinguish the 221 passive interfaces from other normal interfaces. One viable way is 222 to judge the adjacency of interfaces. If the number of adjacency of 223 the interface is zero, then such interfaces can be reported via the 224 newly defined "Stub Link NLRI". 226 The "Local Node Descriptors" should describe the characteristics of 227 ASBRs that are connected these stub links. 229 When such information is reported via the BGP-LS protocol, the SDN 230 controller can construct the underlay inter-domain topology according 231 to procedure described in Section 7 233 5.2. Inter-AS TE Scenario 235 When IGP A or IGP B in Figure 1 runs IS-IS TE/OSPF-TE 236 protocol,[RFC5316] and [RFC5392] define IS-IS and OSPF extensions 237 respectively to deal with the situation for inter-AS traffic 238 engineering. Three new sub-TLVs(Remote AS Number、IPv4 Remote 239 ASBR ID、IPv6 Remote ASBR ID) which are associated with the 240 inter-AS TE link are defined. 242 These TLVs are flooded within the IGP domain automatically. They 243 should be carried within the newly defined Stub Link NLRI within the 244 BGP-LS protocol, as the descriptors for the inter-AS stub link. 246 The "Local Node Descriptors" should describe the the characteristics 247 of ASBRs that are connected these inter-AS TE links. 249 If the SDN controller knows these information via one of the interior 250 router that runs BGP-LS protocol, the SDN controller can rebuild the 251 inter-AS TE topology correctly according to the procedure described 252 in Section 7 254 6. Inter-AS TE NLRI related TLVs 256 This draft proposes to add three new TLVs that is included within the 257 Stub Link NLRI to transfer the information via BGP-LS, which are 258 required to build the inter-AS TE related topology by the SDN 259 controller. 261 The following Link Descriptor TLVs are added into the BGP-LS protocol 262 : 264 +-----------+---------------------+--------------+----------------+ 265 | TLV Code | Description |IS-IS/OSPF TLV| Reference | 266 | Point | | /Sub-TLV | (RFC/Section) | 267 +-----------+---------------------+--------------+----------------+ 268 | TBD |Remote AS Number | 24/21 | [RFC5316]/3.3.1| 269 | | | | [RFC5392]/3.3.1| 270 | TBD |IPv4 Remote ASBR ID | 25/22 | [RFC5316]/3.3.2| 271 | | | | [RFC5392]/3.3.2| 272 | TBD |IPv6 Remote ASBR ID | 26/24 | [RFC5316]/3.3.3| 273 | | | | [RFC5392]/3.3.3| 274 +-----------+---------------------+--------------+----------------+ 275 Figure 3: Link Descriptor TLVs 277 Detail encoding of these TLVs are synchronized with the corresponding 278 parts in [RFC5316] and [RFC5392], which keeps the BGP-LS protocol 279 agnostic to the underly protocol. 281 6.1. Remote AS Number TLV 283 A new TLV, the remote AS number TLV, is defined for inclusion in the 284 link descriptor when advertising inter-AS TE links. The remote AS 285 number TLV specifies the AS number of the neighboring AS to which the 286 advertised link connects. 288 The remote AS number TLV is TLV type TBD (seeSection 9 ) and is 4 289 octets in length. The format is as follows: 291 0 1 2 3 292 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 1 293 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 294 | Type | Length | 295 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 296 | Remote AS Number | 297 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 298 Figure 4: Remote AS Number TLV Format 300 The Remote AS number field has 4 octets. When only 2 octets are used 301 for the AS number, as in current deployments, the left (high-order) 2 302 octets MUST be set to 0. The remote AS number TLV MUST be included 303 when a router advertises an inter-AS TE link. 305 6.2. IPv4 Remote ASBR ID 307 A new TLV, which is referred to as the IPv4 remote ASBR ID TLV, is 308 defined for inclusion in the link descriptor when advertising inter- 309 AS TE links. The IPv4 remote ASBR ID TLV specifies the IPv4 310 identifier of the remote ASBR to which the advertised inter-AS link 311 connects. This could be any stable and routable IPv4 address of the 312 remote ASBR. Use of the TE Router ID as specified in the Traffic 313 Engineering router ID TLV [RFC5305] is RECOMMENDED. 315 The IPv4 remote ASBR ID TLV is TLV type TBD (see Section 9) and is 4 316 octets in length. The format of the IPv4 remote ASBR ID sub-TLV is 317 as follows: 319 0 1 2 3 320 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 1 321 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 322 | Type | Length | 323 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 324 | Remote ASBR ID | 325 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 326 Figure 5: IPv4 Remote ASBR ID TLV Format 328 The IPv4 remote ASBR ID TLV MUST be included if the neighboring ASBR 329 has an IPv4 address. If the neighboring ASBR does not have an IPv4 330 address (not even an IPv4 TE Router ID), the IPv6 remote ASBR ID TLV 331 MUST be included instead. An IPv4 remote ASBR ID TLV and IPv6 remote 332 ASBR ID TLV MAY both be present in an inter-AS TE link NLRI. 334 6.3. IPv6 Remote ASBR ID 336 A new TLV, which is referred to as the IPv6 remote ASBR ID TLV, is 337 defined for inclusion in the link descriptor when advertising inter- 338 AS links. The IPv6 remote ASBR ID TLV specifies the IPv6 identifier 339 of the remote ASBR to which the advertised inter-AS link connects. 340 This could be any stable and routable IPv6 address of the remote 341 ASBR. Use of the TE Router ID as specified in the IPv6 Traffic 342 Engineering router ID TLV [RFC6119] is RECOMMENDED. 344 The IPv6 remote ASBR ID TLV is TLV type TBD (see Section 9) and is 16 345 octets in length. The format of the IPv6 remote ASBR ID TLV is as 346 follows: 348 0 1 2 3 349 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 1 350 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 351 | Type | Length | 352 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 353 | Remote ASBR ID | 354 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 355 | Remote ASBR ID (continued) | 356 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 357 | Remote ASBR ID (continued) | 358 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 359 | Remote ASBR ID (continued) | 360 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 361 Figure 6: IPv6 Remote ASBR ID TLV Format 363 The IPv6 remote ASBR ID TLV MUST be included if the neighboring ASBR 364 has an IPv6 address. If the neighboring ASBR does not have an IPv6 365 address, the IPv4 remote ASBR ID TLV MUST be included instead. An 366 IPv4 remote ASBR ID TLV and IPv6 remote ASBR ID TLV MAY both be 367 present in an inter-AS TE link NLRI. 369 7. Topology Reconstruction. 371 When SDN controller gets such information from BGP-LS protocol, it 372 should compares the proximity of these stub links. If they are under 373 the same network scope and in different AS, then it should find the 374 corresponding associated router information, build the link between 375 these two border routers. 377 If the prefixes reported via the "Stub Link" NLRI are under the same 378 network scope, and in the same AS, the SDN controller can then 379 determine there is some IGP adjacency irregular. The usage of such 380 information is out of scope of this draft. 382 After iterating the above procedures for all of the stub links, the 383 SDN controller can then retrieve the connection topology between 384 different domains automatically. 386 8. Security Considerations 388 It is common for one operator to occupy several IGP domains that are 389 composited by its backbone network and several MAN(Metrio-Area- 390 Network)s/Internet Data Centers (IDCs). When they do traffic 391 engineering which spans MAN, Backbone and IDC, they need to know the 392 inter-as topology via the process described in this draft. Using the 393 passive interface features or configuring the Traffic Engineering 394 (TE) parameters on the interconnect links will not spread the 395 topology fluctuation across each other domain. 397 9. IANA Considerations 399 This document defines: 401 o A new BGP NLRI Type: Stub Link NLRI. The codepoint is from the 402 "BGP-LS NLRI Types" 404 o Three new Link Descriptors TLV: Remote AS Number TLV, IPv4 Remote 405 ASBR ID, IPv6 Remote ASBR ID. The codepoint are from "BGP-LS Node 406 Descriptor, Link Descriptor, Prefix Descriptor, and Attribute 407 TLVs" registry. 409 9.1. New BGP-LS NLRI type 411 This document defines a new value in the registry "BGP-LS NLRI 412 Types": 414 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 415 | Code Point | Description | Status | 416 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 417 | TBD | Stub Link NLRI | Allocation from IANA | 418 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 419 Figure 7: Stub Link NLRI Codepoint 421 9.2. New Link Descriptors 423 This document defines three new values in the registry "BGP-LS Node 424 Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs": 426 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 427 | Code Point | Description | Status | 428 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 429 | TBD | Remote AS Number | Allocation from IANA | 430 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 431 | TBD |IPv4 Remote ASBR ID| Allocation from IANA | 432 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 433 | TBD |IPv6 Remote ASBR ID| Allocation from IANA | 434 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 435 Figure 8: BGP-LS Link Descriptors TLV 437 10. Acknowledgement 439 The author would like to thank Acee Lindem, Jie Dong, Jeff Tantsura 440 and Dhruv Dhody for their valuable comments and suggestions. 442 11. References 444 11.1. Normative References 446 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 447 Requirement Levels", BCP 14, RFC 2119, 448 DOI 10.17487/RFC2119, March 1997, 449 . 451 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 452 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 453 2008, . 455 [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in 456 Support of Inter-Autonomous System (AS) MPLS and GMPLS 457 Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316, 458 December 2008, . 460 [RFC5392] Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in 461 Support of Inter-Autonomous System (AS) MPLS and GMPLS 462 Traffic Engineering", RFC 5392, DOI 10.17487/RFC5392, 463 January 2009, . 465 [RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic 466 Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119, 467 February 2011, . 469 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 470 S. Ray, "North-Bound Distribution of Link-State and 471 Traffic Engineering (TE) Information Using BGP", RFC 7752, 472 DOI 10.17487/RFC7752, March 2016, 473 . 475 11.2. Informative References 477 [I-D.ietf-idr-bgpls-segment-routing-epe] 478 Previdi, S., Talaulikar, K., Filsfils, C., Patel, K., Ray, 479 S., and J. Dong, "BGP-LS extensions for Segment Routing 480 BGP Egress Peer Engineering", draft-ietf-idr-bgpls- 481 segment-routing-epe-19 (work in progress), May 2019. 483 [I-D.ietf-teas-native-ip-scenarios] 484 Wang, A., Huang, X., Qou, C., Li, Z., and P. Mi, 485 "Scenarios and Simulation Results of PCE in Native IP 486 Network", draft-ietf-teas-native-ip-scenarios-09 (work in 487 progress), September 2019. 489 Authors' Addresses 491 Aijun Wang 492 China Telecom 493 Beiqijia Town, Changping District 494 Beijing, Beijing 102209 495 China 497 Email: wangaj3@chinatelecom.cn 499 Huaimo Chen 500 Futurewei 501 Boston, MA 502 USA 504 Email: hchen@futurewei.com 506 Ketan Talaulikar 507 Cisco Systems 509 Email: ketant@cisco.com 510 Shunwan Zhuang 511 Huawei Technologies 512 Huawei Building, No.156 Beiqing Rd. 513 Beijing 100095 514 China 516 Email: zhuangshunwan@huawei.com 518 Shaowen Ma 519 Mellanox Technologies 521 Email: mashaowen@gmail.com