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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Inter-Domain Routing S. Previdi, Ed. 3 Internet-Draft K. Talaulikar 4 Intended status: Standards Track C. Filsfils 5 Expires: October 13, 2018 Cisco Systems, Inc. 6 H. Gredler 7 RtBrick Inc. 8 M. Chen 9 Huawei Technologies 10 April 11, 2018 12 BGP Link-State extensions for Segment Routing 13 draft-ietf-idr-bgp-ls-segment-routing-ext-06 15 Abstract 17 Segment Routing (SR) allows for a flexible definition of end-to-end 18 paths by encoding paths as sequences of topological sub-paths, called 19 "segments". These segments are advertised by routing protocols e.g. 20 by the link state routing protocols (IS-IS, OSPFv2 and OSPFv3) within 21 IGP topologies. 23 This draft defines extensions to the BGP Link-state address-family in 24 order to carry segment routing information via BGP. 26 Requirements Language 28 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 29 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 30 document are to be interpreted as described in RFC 2119 [RFC2119]. 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 October 13, 2018. 49 Copyright Notice 51 Copyright (c) 2018 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 . . . . . . . . . . . . . . . . . . . . . . . . 3 67 2. BGP-LS Extensions for Segment Routing . . . . . . . . . . . . 5 68 2.1. Node Attributes TLVs . . . . . . . . . . . . . . . . . . 5 69 2.1.1. SID/Label Sub-TLV . . . . . . . . . . . . . . . . . . 5 70 2.1.2. SR-Capabilities TLV . . . . . . . . . . . . . . . . . 6 71 2.1.3. SR-Algorithm TLV . . . . . . . . . . . . . . . . . . 7 72 2.1.4. SR Local Block TLV . . . . . . . . . . . . . . . . . 8 73 2.1.5. SRMS Preference TLV . . . . . . . . . . . . . . . . . 9 74 2.2. Link Attribute TLVs . . . . . . . . . . . . . . . . . . . 9 75 2.2.1. Adjacency SID TLV . . . . . . . . . . . . . . . . . . 10 76 2.2.2. LAN Adjacency SID TLV . . . . . . . . . . . . . . . . 11 77 2.2.3. L2 Bundle Member . . . . . . . . . . . . . . . . . . 12 78 2.3. Prefix Attribute TLVs . . . . . . . . . . . . . . . . . . 13 79 2.3.1. Prefix-SID TLV . . . . . . . . . . . . . . . . . . . 14 80 2.3.2. Prefix Attribute Flags TLV . . . . . . . . . . . . . 15 81 2.3.3. Source Router Identifier (Source Router-ID) TLV . . . 16 82 2.3.4. Range TLV . . . . . . . . . . . . . . . . . . . . . . 16 83 2.4. Equivalent IS-IS Segment Routing TLVs/Sub-TLVs . . . . . 18 84 2.5. Equivalent OSPFv2/OSPFv3 Segment Routing TLVs/Sub-TLVs . 18 85 3. Implementation Status . . . . . . . . . . . . . . . . . . . . 19 86 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 87 4.1. TLV/Sub-TLV Code Points Summary . . . . . . . . . . . . . 20 88 5. Manageability Considerations . . . . . . . . . . . . . . . . 21 89 5.1. Operational Considerations . . . . . . . . . . . . . . . 21 90 5.1.1. Operations . . . . . . . . . . . . . . . . . . . . . 21 91 6. Security Considerations . . . . . . . . . . . . . . . . . . . 21 92 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 21 93 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 22 94 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 22 95 9.1. Normative References . . . . . . . . . . . . . . . . . . 22 96 9.2. Informative References . . . . . . . . . . . . . . . . . 23 97 9.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 24 98 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25 100 1. Introduction 102 Segment Routing (SR) allows for a flexible definition of end-to-end 103 paths by combining sub-paths called "segments". A segment can 104 represent any instruction, topological or service-based. A segment 105 can have a local semantic to an SR node or global within a domain. 106 Within IGP topologies an SR path is encoded as a sequence of 107 topological sub-paths, called "IGP segments". These segments are 108 advertised by the link-state routing protocols (IS-IS, OSPFv2 and 109 OSPFv3). 111 Two types of IGP segments are defined, Prefix segments and Adjacency 112 segments. Prefix segments, by default, represent an ECMP-aware 113 shortest-path to a prefix, as per the state of the IGP topology. 114 Adjacency segments represent a hop over a specific adjacency between 115 two nodes in the IGP. A prefix segment is typically a multi-hop path 116 while an adjacency segment, in most of the cases, is a one-hop path. 117 [I-D.ietf-spring-segment-routing]. 119 When Segment Routing is enabled in a IGP domain, segments are 120 advertised in the form of Segment Identifiers (SIDs). The IGP link- 121 state routing protocols have been extended to advertise SIDs and 122 other SR-related information. IGP extensions are described in: IS-IS 123 [I-D.ietf-isis-segment-routing-extensions], OSPFv2 124 [I-D.ietf-ospf-segment-routing-extensions] and OSPFv3 125 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. Using these 126 extensions, Segment Routing can be enabled within an IGP domain. 128 +------------+ 129 | Consumer | 130 +------------+ 131 ^ 132 | 133 v 134 +-------------------+ 135 | BGP Speaker | +-----------+ 136 | (Route-Reflector) | | Consumer | 137 +-------------------+ +-----------+ 138 ^ ^ ^ ^ 139 | | | | 140 +---------------+ | +-------------------+ | 141 | | | | 142 v v v v 143 +-----------+ +-----------+ +-----------+ 144 | BGP | | BGP | | BGP | 145 | Speaker | | Speaker | . . . | Speaker | 146 +-----------+ +-----------+ +-----------+ 147 ^ ^ ^ 148 | | | 149 IGP IGP IGP 151 Figure 1: Link State info collection 153 Segment Routing (SR) allows advertisement of single or multi-hop 154 paths. The flooding scope for the IGP extensions for Segment routing 155 is IGP area-wide. Consequently, the contents of a Link State 156 Database (LSDB) or a Traffic Engineering Database (TED) has the scope 157 of an IGP area and therefore, by using the IGP alone it is not enough 158 to construct segments across multiple IGP Area or AS boundaries. 160 In order to address the need for applications that require 161 topological visibility across IGP areas, or even across Autonomous 162 Systems (AS), the BGP-LS address-family/sub-address-family have been 163 defined to allow BGP to carry Link-State information. The BGP 164 Network Layer Reachability Information (NLRI) encoding format for 165 BGP-LS and a new BGP Path Attribute called the BGP-LS attribute are 166 defined in [RFC7752]. The identifying key of each Link-State object, 167 namely a node, link, or prefix, is encoded in the NLRI and the 168 properties of the object are encoded in the BGP-LS attribute. 169 Figure 1 describes a typical deployment scenario. In each IGP area, 170 one or more nodes are configured with BGP-LS. These BGP speakers 171 form an IBGP mesh by connecting to one or more route-reflectors. 172 This way, all BGP speakers (specifically the route-reflectors) obtain 173 Link-State information from all IGP areas (and from other ASes from 174 EBGP peers). An external component connects to the route-reflector 175 to obtain this information (perhaps moderated by a policy regarding 176 what information is or isn't advertised to the external component). 178 This document describes extensions to BGP-LS to advertise the SR 179 information. An external component (e.g., a controller) then can 180 collect SR information in the "northbound" direction across IGP areas 181 or ASes and construct the end-to-end path (with its associated SIDs) 182 that need to be applied to an incoming packet to achieve the desired 183 end-to-end forwarding. 185 2. BGP-LS Extensions for Segment Routing 187 This document defines SR extensions to BGP-LS and specifies the TLVs 188 and sub-TLVs for advertising SR information. Section 2.4 and 189 Section 2.5 illustrates the equivalent TLVs and sub-TLVs in IS-IS, 190 OSPFv2 and OSPFv3 protocols. 192 BGP-LS [RFC7752] defines the BGP-LS NLRI that can be a Node NLRI, a 193 Link NLRI or a Prefix NLRI. The corresponding BGP-LS attribute is a 194 Node Attribute, a Link Attribute or a Prefix Attribute. BGP-LS 195 [RFC7752] defines the TLVs that map link-state information to BGP-LS 196 NLRI and the BGP-LS attribute. This document adds additional BGP-LS 197 attribute TLVs in order to encode SR information. 199 2.1. Node Attributes TLVs 201 The following Node Attribute TLVs are defined: 203 +-----------------+----------+---------------+ 204 | Description | Length | Section | 205 +-----------------+----------+---------------+ 206 | SID/Label | variable | Section 2.1.1 | 207 | SR Capabilities | variable | Section 2.1.2 | 208 | SR Algorithm | variable | Section 2.1.3 | 209 | SR Local Block | variable | Section 2.1.4 | 210 | SRMS Preference | variable | Section 2.1.5 | 211 +-----------------+----------+---------------+ 213 Table 1: Node Attribute TLVs 215 These TLVs can ONLY be added to the Node Attribute associated with 216 the Node NLRI that originates the corresponding SR TLV. 218 2.1.1. SID/Label Sub-TLV 220 The SID/Label TLV is used as sub-TLV by the SR-Capabilities 221 (Section 2.1.2) and SRLB (Section 2.1.4) TLVs and has the following 222 format: 224 0 1 2 3 225 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 1 226 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 227 | Type | Length | 228 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 229 | SID/Label (variable) | 230 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 232 where: 234 Type: TBD, see Section 4. 236 Length: Variable, 3 or 4. 238 SID/Label: If length is set to 3, then the 20 rightmost bits 239 represent a label. If length is set to 4, then the value 240 represents a 32 bit SID. 242 The receiving router MUST ignore the SID/Label sub-TLV if the 243 length is other then 3 or 4. 245 2.1.2. SR-Capabilities TLV 247 The SR-Capabilities TLV is used in order to advertise the node's SR 248 Capabilities and its Segment Routing Global Base (SRGB) range(s). 249 This information is derived from the protocol specific 250 advertisements. 252 o IS-IS, as defined by the SR-Capabilities TLV in 253 [I-D.ietf-isis-segment-routing-extensions]. 255 o OSPFv2/OSPFv3, as defined by the SID/Label Range TLV in 256 [I-D.ietf-ospf-segment-routing-extensions] and 257 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 259 The SR Capabilities TLV has following format: 261 0 1 2 3 262 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 1 263 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 264 | Type | Length | 265 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 266 | Flags | Reserved | 267 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 269 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 270 | Range Size | 271 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 272 // SID/Label sub-TLV (variable) // 273 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 275 Type: TBD, see Section 4. 277 Length: Variable. 279 Flags: 1 octet of flags as defined in 280 [I-D.ietf-isis-segment-routing-extensions]. 282 Reserved: 1 octet that SHOULD be set to 0 and MUST be ignored on 283 receipt. 285 One or more entries, each of which have the following format: 287 Range Size: 3 octet value indicating the number of labels in 288 the range. 290 SID/Label sub-TLV (as defined in Section 2.1.1) which encodes 291 the first label in the range. 293 2.1.3. SR-Algorithm TLV 295 The SR-Algorithm TLV has the following format: 297 0 1 2 3 298 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 1 299 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 300 | Type | Length | 301 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 302 | Algorithm 1 | Algorithm... | Algorithm N | | 303 +- -+ 304 | | 305 + + 307 where: 309 Type: TBD, see Section 4. 311 Length: Variable. 313 Algorithm: 1 octet identifying the algorithm. 315 2.1.4. SR Local Block TLV 317 The SR Local Block (SRLB) TLV contains the range(s) of labels the 318 node has reserved for local SIDs. Local SIDs are used, e.g., in IGP 319 (IS-IS, OSPF) for Adjacency-SIDs, and may also be allocated by 320 components other than IGP protocols. As an example, an application 321 or a controller may instruct a node to allocate a specific local SID. 322 Therefore, in order for such applications or controllers to know the 323 range of local SIDs available, it is required that the node 324 advertises its SRLB. 326 The SRLB TLV has the following format: 328 0 1 2 3 329 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 1 330 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 331 | Type | Length | 332 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 333 | Flags | Reserved | 334 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 336 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 337 | Range Size | 338 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 339 // SID/Label sub-TLV (variable) // 340 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 342 Type: TBD, see Section 4. 344 Length: Variable. 346 Flags: 1 octet of flags. None are defined at this stage. 348 Reserved: 1 octet that SHOULD be set to 0 and MUST be ignored on 349 receipt. 351 One or more entries, each of which have the following format: 353 Range Size: 3 octet value indicating the number of labels in 354 the range. 356 SID/Label sub-TLV (as defined in Section 2.1.1) which encodes 357 the first label in the range. 359 2.1.5. SRMS Preference TLV 361 The Segment Routing Mapping Server (SRMS) Preference TLV is used in 362 order to associate a preference with SRMS advertisements from a 363 particular source. 365 The SRMS Preference TLV has following format: 367 0 1 2 3 368 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 1 369 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 370 | Type | Length | 371 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 372 | Preference | 373 +-+-+-+-+-+-+-+-+ 375 Type: TBD, see Section 4. 377 Length: 1. 379 Preference: 1 octet. Unsigned 8 bit SRMS preference. 381 The use of the SRMS Preference TLV is defined in 382 [I-D.ietf-isis-segment-routing-extensions], 383 [I-D.ietf-ospf-segment-routing-extensions] and 384 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 386 2.2. Link Attribute TLVs 388 The following Link Attribute TLVs are are defined: 390 +----------------------------------------+----------+---------------+ 391 | Description | Length | Section | 392 +----------------------------------------+----------+---------------+ 393 | Adjacency Segment Identifier (Adj-SID) | variable | Section 2.2.1 | 394 | TLV | | | 395 | LAN Adjacency Segment Identifier (Adj- | variable | Section 2.2.2 | 396 | SID) TLV | | | 397 | L2 Bundle Member TLV | variable | Section 2.2.3 | 398 +----------------------------------------+----------+---------------+ 400 Table 2: Link Attribute TLVs 402 These TLVs can ONLY be added to the Link Attribute associated with 403 the link whose local node originates the corresponding TLV. 405 For a LAN, normally a node only announces its adjacency to the IS-IS 406 pseudo-node (or the equivalent OSPF Designated and Backup Designated 407 Routers)[I-D.ietf-isis-segment-routing-extensions]. The LAN 408 Adjecency Segment TLV allows a node to announce adjacencies to all 409 other nodes attached to the LAN in a single instance of the BGP-LS 410 Link NLRI. Without this TLV, the corresponding BGP-LS link NLRI 411 would need to be originated for each additional adjacency in order to 412 advertise the SR TLVs for these neighbor adjacencies. 414 2.2.1. Adjacency SID TLV 416 The Adjacency SID (Adj-SID) TLV has the following format: 418 0 1 2 3 419 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 1 420 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 421 | Type | Length | 422 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 423 | Flags | Weight | Reserved | 424 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 425 | SID/Label/Index (variable) | 426 +---------------------------------------------------------------+ 428 where: 430 Type: TBD, see Section 4. 432 Length: Variable, 7 or 8 depending on Label or Index encoding of 433 the SID 435 Flags. 1 octet field of following flags as defined in 436 [I-D.ietf-isis-segment-routing-extensions], 437 [I-D.ietf-ospf-segment-routing-extensions] and 438 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 440 Weight: Weight used for load-balancing purposes. 442 Reserved: 2 octets that SHOULD be set to 0 and MUST be ignored on 443 receipt. 445 SID/Index/Label: Label or index value depending on the flags 446 setting as defined in [I-D.ietf-isis-segment-routing-extensions], 447 [I-D.ietf-ospf-segment-routing-extensions] and 448 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 450 2.2.2. LAN Adjacency SID TLV 452 The LAN Adjacency SID (LAN-Adj-SID-SID) TLV has the following format: 454 0 1 2 3 455 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 1 456 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 457 | Type | Length | 458 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 459 | Flags | Weight | Reserved | 460 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 462 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 463 | OSPF Neighbor ID / IS-IS System-ID | 464 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 465 | | 466 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 468 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 469 | SID/Label/Index (variable) | 470 +---------------------------------------------------------------+ 472 where: 474 Type: TBD, see Section 4. 476 Length: Variable. For ISIS it would be 13 or 14 depending on 477 Label or Index encoding of the SID. For OSPF it would be 11 or 12 478 depending on Label or Index encoding of the SID. 480 Flags. 1 octet field of following flags as defined in 481 [I-D.ietf-isis-segment-routing-extensions], 482 [I-D.ietf-ospf-segment-routing-extensions] and 483 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 485 Weight: Weight used for load-balancing purposes. 487 Reserved: 2 octets that SHOULD be set to 0 and MUST be ignored on 488 receipt. 490 SID/Index/Label: Label or index value depending on the flags 491 setting as defined in [I-D.ietf-isis-segment-routing-extensions], 492 [I-D.ietf-ospf-segment-routing-extensions] and 493 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 495 2.2.3. L2 Bundle Member 497 The L2 Bundle Member Attribute TLV identifies an L2 Bundle Member 498 link which in turn is associated with a parent L3 link. The L3 link 499 is described by the Link NLRI defined in [RFC7752] and the L2 Bundle 500 Member Attribute TLV is associated with the Link NLRI. The TLV MAY 501 include sub-TLVs which describe attributes associated with the bundle 502 member. The identified bundle member represents a unidirectional 503 path from the originating router to the neighbor specified in the 504 parent L3 Link. Multiple L2 Bundle Member Attribute TLVs MAY be 505 associated with a Link NLRI. 507 The L2 Bundle Member Attribute TLV has the following format: 509 0 1 2 3 510 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 1 511 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 512 | Type | Length | 513 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 515 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 516 | L2 Bundle Member Descriptor | 517 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 518 // Link attribute sub-TLVs(variable) // 519 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 521 where: 523 Type: TBD, see Section 4. 525 Length: Variable. 527 L2 Bundle Member Descriptor: A Link Local Identifier as defined in 528 [RFC4202]. 530 Link attributes for L2 Bundle Member Links are advertised as sub-TLVs 531 of the L2Bundle Member Attribute TLV. The sub-TLVs are identical to 532 existing BGP-LS TLVs as identified in the table below. 534 +-----------+----------------------------+--------------------------+ 535 | TLV Code | Description | Reference Document | 536 | Point | | | 537 +-----------+----------------------------+--------------------------+ 538 | 1088 | Administrative group | [RFC7752] | 539 | | (color) | | 540 | 1089 | Maximum link bandwidth | [RFC7752] | 541 | 1090 | Max. reservable link | [RFC7752] | 542 | | bandwidth | | 543 | 1091 | Unreserved bandwidth | [RFC7752] | 544 | 1092 | TE default metric | [RFC7752] | 545 | 1093 | Link protection type | [RFC7752] | 546 | 1099 | Adjacency Segment | Section 2.2.1 | 547 | | Identifier (Adj-SID) TLV | | 548 | 1100 | LAN Adjacency Segment | Section 2.2.2 | 549 | | Identifier (Adj-SID) TLV | | 550 | 1104 | Unidirectional link delay | [I-D.ietf-idr-te-pm-bgp] | 551 | 1105 | Min/Max Unidirectional | [I-D.ietf-idr-te-pm-bgp] | 552 | | link delay | | 553 | 1106 | Min/Max Unidirectional | [I-D.ietf-idr-te-pm-bgp] | 554 | | link delay | | 555 | 1107 | Unidirectional packet loss | [I-D.ietf-idr-te-pm-bgp] | 556 | 1108 | Unidirectional residual | [I-D.ietf-idr-te-pm-bgp] | 557 | | bandwidth | | 558 | 1109 | Unidirectional available | [I-D.ietf-idr-te-pm-bgp] | 559 | | bandwidth | | 560 | 1110 | Unidirectional bandwidth | [I-D.ietf-idr-te-pm-bgp] | 561 | | utilization | | 562 +-----------+----------------------------+--------------------------+ 564 Table 3: L2 Bundle Member Link Attribute TLVs 566 2.3. Prefix Attribute TLVs 568 The following Prefix Attribute TLVs are defined: 570 +------------------------+----------+---------------+ 571 | Description | Length | Section | 572 +------------------------+----------+---------------+ 573 | Prefix SID | variable | Section 2.3.1 | 574 | Range | variable | Section 2.3.4 | 575 | Prefix Attribute Flags | variable | Section 2.3.2 | 576 | Source Router-ID | variable | Section 2.3.3 | 577 +------------------------+----------+---------------+ 579 Table 4: Prefix Attribute TLVs 581 2.3.1. Prefix-SID TLV 583 The Prefix-SID TLV can ONLY be added to the Prefix Attribute whose 584 local node in the corresponding Prefix NLRI is the node that 585 originates the corresponding SR TLV. 587 The Prefix-SID TLV is used in order to advertise information related 588 to a Prefix-SID. This information is originated in: 590 o IS-IS, as defined by the Prefix-SID TLV in 591 [I-D.ietf-isis-segment-routing-extensions]. 593 o OSPFv2/OSPFv3, as defined by the Prefix-SID TLV in 594 [I-D.ietf-ospf-segment-routing-extensions] and 595 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 597 The Prefix-SID has the following format: 599 0 1 2 3 600 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 1 601 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 602 | Type | Length | 603 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 604 | Flags | Algorithm | Reserved | 605 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 606 | SID/Index/Label (variable) | 607 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 609 where: 611 Type: TBD, see Section 4. 613 Length: Variable, 7 or 8 depending on Label or Index encoding of 614 the SID 616 Algorithm: 1 octet value identify the algorithm. 618 Reserved: 2 octets that SHOULD be set to 0 and MUST be ignored on 619 receipt. 621 SID/Index/Label: 623 * IS-IS: Label or index value as defined in 624 [I-D.ietf-isis-segment-routing-extensions], 626 * OSPFv2: Label or index value as defined in 627 [I-D.ietf-ospf-segment-routing-extensions], 629 * OSPFv3: Label or index value as defined in 630 [I-D.ietf-ospf-ospfv3-segment-routing-extensions], 632 The Prefix-SID TLV includes a Flags field. In the context of BGP-LS, 633 the Flags field format and the semantic of each individual flag MUST 634 be taken from the corresponding source protocol (i.e.: the protocol 635 of origin of the Prefix-SID being advertised in BGP-LS). 637 IS-IS Prefix-SID flags are defined in 638 [I-D.ietf-isis-segment-routing-extensions] section 2.1. 640 OSPFv2 Prefix-SID flags are defined in 641 [I-D.ietf-ospf-segment-routing-extensions] section 5. 643 OSPFv3 Prefix-SID flags are defined in 644 [I-D.ietf-ospf-segment-routing-extensions] section 5. 646 2.3.2. Prefix Attribute Flags TLV 648 The Prefix Attribute Flags TLV carries IPv4/IPv6 prefix attribute 649 flags information. These flags are defined for OSPFv2 in [RFC7684], 650 for OSPFv3 in [RFC5340] and for ISIS in [RFC7794]. 652 The Prefix Attribute Flags TLV has the following format: 654 0 1 2 3 655 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 1 656 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 657 | Type | Length | 658 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 659 // Flags (variable) // 660 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 662 where: 664 Type: TBD, see Section 4. 666 Length: variable. 668 Flags: a variable length flag field (according to the length 669 field). Flags are routing protocol specific. OSPFv2 flags are 670 defined in [RFC7684], for OSPFv3 this maps to the Prefix Options 671 field defined in [RFC5340] and IS-IS flags are defined in 672 [RFC7794]. The receiver of the BGP-LS update, when inspecting the 673 Prefix Attribute Flags TLV, MUST check the Protocol-ID of the NLRI 674 and refer to the protocol specification in order to parse the 675 flags. 677 2.3.3. Source Router Identifier (Source Router-ID) TLV 679 The Source Router-ID TLV contains the IPv4 or IPv6 Router-ID of the 680 originator of the Prefix. For IS-IS protocol this is as defined in 681 [RFC7794]. The Source Router-ID TLV may be used to carry the OSPF 682 Router-ID of the prefix originator. 684 The Source Router-ID TLV has the following format: 686 0 1 2 3 687 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 1 688 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 689 | Type | Length | 690 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 691 // IPv4/IPv6 Address (Router-ID) // 692 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 694 where: 696 Type: TBD, see Section 4. 698 Length: 4 or 16. 700 IPv4/IPv6 Address: 4 octet IPv4 address or 16 octet IPv6 address. 702 The semantic of the Source Router-ID TLV is defined in [RFC7794]. 704 2.3.4. Range TLV 706 The Range TLV can ONLY be added to the Prefix Attribute whose local 707 node in the corresponding Prefix NLRI is the node that originates the 708 corresponding SR TLV. 710 When the range TLV is used in order to advertise a range of prefix- 711 to-SID mappings as defined in 712 [I-D.ietf-ospf-segment-routing-extensions], 713 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] and 714 [I-D.ietf-isis-segment-routing-extensions]. The Prefix-NLRI the 715 Range TLV is attached to MUST be advertised as a non-routing prefix 716 where no IGP metric TLV (TLV 1095) is attached. 718 The format of the Range TLV is as follows: 720 0 1 2 3 721 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 1 722 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 723 | Type | Length | 724 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 725 | Flags | Reserved | Range Size | 726 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 727 // sub-TLVs // 728 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 730 where: 732 Figure 2: Range TLV format 734 Type: TBD, see Section 4. 736 Length: variable 738 Flags: as defined in [I-D.ietf-ospf-segment-routing-extensions], 739 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] and 740 [I-D.ietf-isis-segment-routing-extensions]. 742 Reserved: 1 octet that SHOULD be set to 0 and MUST be ignored on 743 receipt. 745 Range Size: 2 octets as defined in 746 [I-D.ietf-ospf-segment-routing-extensions]. 748 Within the Range TLV, the prefix-to-SID mappings are advertised using 749 sub-TLVs as below: 751 2.3.4.1. Advertisement Procedure for OSPF 753 The OSPFv2/OSPFv3 Extended Prefix Range TLV is encoded in the Range 754 TLV. The flags of the Range TLV have the semantic mapped to the 755 definition in [I-D.ietf-ospf-segment-routing-extensions] section 4 or 756 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] section 4. The 757 Prefix-SID from the original OSPF Prefix SID sub-TLV is encoded using 758 the BGP-LS Prefix Attribute Prefix-SID as defined in Section 2.3.1 759 with the flags set according to the definition in 760 [I-D.ietf-ospf-segment-routing-extensions] section 5 or 761 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] section 5. 763 2.3.4.2. Advertisement Procedure for IS-IS 765 The advertisement of a range of IS-IS Mapping Server bindings 766 ([I-D.ietf-isis-segment-routing-extensions]) is encoded in the Range 767 TLV using the following TLV/sub-TLV structure: 769 Range TLV 770 Prefix-SID TLV (used as a sub-TLV in this context) 772 where: 774 o The Range TLV is defined in Section 2.3.4. 776 o The Prefix-SID TLV (used as sub-TLV in this context) is defined in 777 Section 2.3.1. 779 2.4. Equivalent IS-IS Segment Routing TLVs/Sub-TLVs 781 This section illustrate the IS-IS Segment Routing Extensions TLVs and 782 sub-TLVs mapped to the ones defined in this document. 784 The following table, illustrates for each BGP-LS TLV, its equivalence 785 in IS-IS. 787 +----------------------------------------+----------+---------------+ 788 | Description | Length | IS-IS TLV | 789 | | | /sub-TLV | 790 +----------------------------------------+----------+---------------+ 791 | SR Capabilities | variable | 2 [1] | 792 | SR Algorithm | variable | 19 [2] | 793 | Adjacency Segment Identifier (Adj-SID) | variable | 31 [3] | 794 | TLV | | | 795 | LAN Adjacency Segment Identifier (LAN- | variable | 32 [4] | 796 | Adj-SID) TLV | | | 797 | Prefix SID | variable | 3 [5] | 798 | SID/Label TLV | variable | 1 [6] | 799 | Prefix Attribute Flags | variable | 4 [7] | 800 | Source Router ID | variable | 11/12 [8] | 801 | L2 Bundle Member TLV | variable | 25 [9] | 802 +----------------------------------------+----------+---------------+ 804 Table 5: IS-IS Segment Routing Extensions TLVs/Sub-TLVs 806 2.5. Equivalent OSPFv2/OSPFv3 Segment Routing TLVs/Sub-TLVs 808 This section illustrate the OSPFv2 and OSPFv3 Segment Routing 809 Extensions TLVs and sub-TLVs mapped to the ones defined in this 810 document. 812 The following table, illustrates for each BGP-LS TLV, its equivalence 813 in OSPFv2 and OSPFv3. 815 +--------------------------------------+----------+-----------------+ 816 | Description | Length | OSPFv2 TLV/sub- | 817 | | | TLV | 818 +--------------------------------------+----------+-----------------+ 819 | SR Capabilities | variable | 9 [10] | 820 | SR Algorithm | variable | 8 [11] | 821 | Adjacency Segment Identifier (Adj- | variable | 2 [12] | 822 | SID) TLV | | | 823 | LAN Adjacency Segment Identifier | variable | 3 [13] | 824 | (Adj-SID) TLV | | | 825 | Prefix SID | variable | 2 [14] | 826 | SID/Label TLV | variable | 1 [15] | 827 | Prefix Attribute Flags | variable | 4 [16] | 828 +--------------------------------------+----------+-----------------+ 830 Table 6: OSPF Segment Routing Extensions TLVs/Sub-TLVs 832 +--------------------------------------+----------+-----------------+ 833 | Description | Length | OSPFv3 TLV/sub- | 834 | | | TLV | 835 +--------------------------------------+----------+-----------------+ 836 | SR Capabilities | variable | 9 [17] | 837 | SR Algorithm | variable | 8 [18] | 838 | Adjacency Segment Identifier (Adj- | variable | 5 [19] | 839 | SID) TLV | | | 840 | LAN Adjacency Segment Identifier | variable | 6 [20] | 841 | (Adj-SID) TLV | | | 842 | Prefix SID | variable | 4 [21] | 843 | SID/Label TLV | variable | 3 [22] | 844 | Prefix Attribute Flags | variable | 4 [23] | 845 +--------------------------------------+----------+-----------------+ 847 Table 7: OSPFv3 Segment Routing Extensions TLVs/Sub-TLVs 849 3. Implementation Status 851 Note to RFC Editor: Please remove this section prior to publication, 852 as well as the reference to RFC 7942. 854 This section records the status of known implementations of the 855 protocol defined by this specification at the time of posting of this 856 Internet-Draft, and is based on a proposal described in [RFC7942]. 857 The description of implementations in this section is intended to 858 assist the IETF in its decision processes in progressing drafts to 859 RFCs. Please note that the listing of any individual implementation 860 here does not imply endorsement by the IETF. Furthermore, no effort 861 has been spent to verify the information presented here that was 862 supplied by IETF contributors. This is not intended as, and must not 863 be construed to be, a catalog of available implementations or their 864 features. Readers are advised to note that other implementations may 865 exist. 867 According to [RFC7942], "this will allow reviewers and working groups 868 to assign due consideration to documents that have the benefit of 869 running code, which may serve as evidence of valuable experimentation 870 and feedback that have made the implemented protocols more mature. 871 It is up to the individual working groups to use this information as 872 they see fit". 874 Several early implementations exist and will be reported in detail in 875 a forthcoming version of this document. For purposes of early 876 interoperability testing, when no FCFS code point was available, 877 implementations have made use of the values described in Table 8. 879 It will ease implementation interoperability and deployment if the 880 value could be preserved also due to the large amount of codepoints 881 this draft requires. However, when IANA-assigned values are 882 available, implementations will be updated to use them. 884 4. IANA Considerations 886 This document requests assigning code-points from the registry "BGP- 887 LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute 888 TLVs" based on table Table 8. The column "IS-IS TLV/Sub-TLV" defined 889 in the registry does not require any value and should be left empty. 891 4.1. TLV/Sub-TLV Code Points Summary 893 This section contains the global table of all TLVs/sub-TLVs defined 894 in this document. 896 +-------------+-------------------------------------+---------------+ 897 | TLV Code | Description | Reference | 898 | Point | | | 899 +-------------+-------------------------------------+---------------+ 900 | 1034 | SR Capabilities | Section 2.1.2 | 901 | 1035 | SR Algorithm | Section 2.1.3 | 902 | 1036 | SR Local Block | Section 2.1.4 | 903 | 1037 | SRMS Preference | Section 2.1.5 | 904 | 1099 | Adjacency Segment Identifier (Adj- | Section 2.2.1 | 905 | | SID) TLV | | 906 | 1100 | LAN Adjacency Segment Identifier | Section 2.2.2 | 907 | | (Adj-SID) TLV | | 908 | 1158 | Prefix SID | Section 2.3.1 | 909 | 1159 | Range | Section 2.3.4 | 910 | 1161 | SID/Label TLV | Section 2.1.1 | 911 | 1170 | Prefix Attribute Flags | Section 2.3.2 | 912 | 1171 | Source Router-ID | Section 2.3.3 | 913 | 1172 | L2 Bundle Member TLV | Section 2.2.3 | 914 +-------------+-------------------------------------+---------------+ 916 Table 8: Summary Table of TLV/Sub-TLV Codepoints 918 5. Manageability Considerations 920 This section is structured as recommended in [RFC5706]. 922 5.1. Operational Considerations 924 5.1.1. Operations 926 Existing BGP and BGP-LS operational procedures apply. No additional 927 operation procedures are defined in this document. 929 6. Security Considerations 931 Procedures and protocol extensions defined in this document do not 932 affect the BGP security model. See the 'Security Considerations' 933 section of [RFC4271] for a discussion of BGP security. Also refer to 934 [RFC4272] and [RFC6952] for analysis of security issues for BGP. 936 7. Contributors 938 The following people have substantially contributed to the editing of 939 this document: 941 Peter Psenak 942 Cisco Systems 943 Email: ppsenak@cisco.com 944 Les Ginsberg 945 Cisco Systems 946 Email: ginsberg@cisco.com 948 Acee Lindem 949 Cisco Systems 950 Email: acee@cisco.com 952 Saikat Ray 953 Individual 954 Email: raysaikat@gmail.com 956 Jeff Tantsura 957 Nuage Networks 958 Email: jefftant.ietf@gmail.com 960 8. Acknowledgements 962 The authors would like to thank Jeffrey Haas and Aijun Wang for their 963 review of this document and their comments. 965 9. References 967 9.1. Normative References 969 [I-D.ietf-idr-te-pm-bgp] 970 Ginsberg, L., Previdi, S., Wu, Q., Tantsura, J., and C. 971 Filsfils, "BGP-LS Advertisement of IGP Traffic Engineering 972 Performance Metric Extensions", draft-ietf-idr-te-pm- 973 bgp-10 (work in progress), March 2018. 975 [I-D.ietf-isis-segment-routing-extensions] 976 Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A., 977 Gredler, H., Litkowski, S., Decraene, B., and J. Tantsura, 978 "IS-IS Extensions for Segment Routing", draft-ietf-isis- 979 segment-routing-extensions-15 (work in progress), December 980 2017. 982 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] 983 Psenak, P., Filsfils, C., Previdi, S., Gredler, H., 984 Shakir, R., Henderickx, W., and J. Tantsura, "OSPFv3 985 Extensions for Segment Routing", draft-ietf-ospf-ospfv3- 986 segment-routing-extensions-11 (work in progress), January 987 2018. 989 [I-D.ietf-ospf-segment-routing-extensions] 990 Psenak, P., Previdi, S., Filsfils, C., Gredler, H., 991 Shakir, R., Henderickx, W., and J. Tantsura, "OSPF 992 Extensions for Segment Routing", draft-ietf-ospf-segment- 993 routing-extensions-24 (work in progress), December 2017. 995 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 996 Requirement Levels", BCP 14, RFC 2119, 997 DOI 10.17487/RFC2119, March 1997, 998 . 1000 [RFC4202] Kompella, K., Ed. and Y. Rekhter, Ed., "Routing Extensions 1001 in Support of Generalized Multi-Protocol Label Switching 1002 (GMPLS)", RFC 4202, DOI 10.17487/RFC4202, October 2005, 1003 . 1005 [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A 1006 Border Gateway Protocol 4 (BGP-4)", RFC 4271, 1007 DOI 10.17487/RFC4271, January 2006, 1008 . 1010 [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF 1011 for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, 1012 . 1014 [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., 1015 Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute 1016 Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 1017 2015, . 1019 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 1020 S. Ray, "North-Bound Distribution of Link-State and 1021 Traffic Engineering (TE) Information Using BGP", RFC 7752, 1022 DOI 10.17487/RFC7752, March 2016, 1023 . 1025 [RFC7794] Ginsberg, L., Ed., Decraene, B., Previdi, S., Xu, X., and 1026 U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4 1027 and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794, 1028 March 2016, . 1030 9.2. Informative References 1032 [I-D.ietf-spring-segment-routing] 1033 Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B., 1034 Litkowski, S., and R. Shakir, "Segment Routing 1035 Architecture", draft-ietf-spring-segment-routing-15 (work 1036 in progress), January 2018. 1038 [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", 1039 RFC 4272, DOI 10.17487/RFC4272, January 2006, 1040 . 1042 [RFC5706] Harrington, D., "Guidelines for Considering Operations and 1043 Management of New Protocols and Protocol Extensions", 1044 RFC 5706, DOI 10.17487/RFC5706, November 2009, 1045 . 1047 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 1048 BGP, LDP, PCEP, and MSDP Issues According to the Keying 1049 and Authentication for Routing Protocols (KARP) Design 1050 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 1051 . 1053 [RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running 1054 Code: The Implementation Status Section", BCP 205, 1055 RFC 7942, DOI 10.17487/RFC7942, July 2016, 1056 . 1058 9.3. URIs 1060 [1] http://tools.ietf.org/html/draft-ietf-isis-segment-routing- 1061 extensions-05#section-3.1 1063 [2] http://tools.ietf.org/html/draft-ietf-isis-segment-routing- 1064 extensions-05#section-3.2 1066 [3] http://tools.ietf.org/html/draft-ietf-isis-segment-routing- 1067 extensions-05#section-2.2.1 1069 [4] http://tools.ietf.org/html/draft-ietf-isis-segment-routing- 1070 extensions-05#section-2.2.2 1072 [5] http://tools.ietf.org/html/draft-ietf-isis-segment-routing- 1073 extensions-05#section-2.1 1075 [6] http://tools.ietf.org/html/draft-ietf-isis-segment-routing- 1076 extensions-05#section-2.3 1078 [7] http://tools.ietf.org/html/RFC7794 1080 [8] http://tools.ietf.org/html/RFC7794 1082 [9] http://tools.ietf.org/html/draft-ietf-isis-l2bundles-05 1084 [10] http://tools.ietf.org/html/draft-ietf-ospf-segment-routing- 1085 extensions-05#section-3.2 1087 [11] http://tools.ietf.org/html/draft-ietf-ospf-segment-routing- 1088 extensions-05#section-3.1 1090 [12] http://tools.ietf.org/html/draft-ietf-ospf-segment-routing- 1091 extensions-05#section-7.1 1093 [13] http://tools.ietf.org/html/draft-ietf-ospf-segment-routing- 1094 extensions-05#section-7.2 1096 [14] http://tools.ietf.org/html/draft-ietf-ospf-segment-routing- 1097 extensions-05#section-5 1099 [15] http://tools.ietf.org/html/draft-ietf-ospf-segment-routing- 1100 extensions-05#section-2.1 1102 [16] http://tools.ietf.org/html/RFC7684#section-2.1 1104 [17] http://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment- 1105 routing-extensions-05#section-3.2 1107 [18] http://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment- 1108 routing-extensions-05#section-3.1 1110 [19] http://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment- 1111 routing-extensions-05#section-7.1 1113 [20] http://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment- 1114 routing-extensions-05#section-7.2 1116 [21] http://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment- 1117 routing-extensions-05#section-5 1119 [22] http://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment- 1120 routing-extensions-05#section-2.1 1122 [23] http://tools.ietf.org/html/RFC5340#section-A.4.1.1 1124 Authors' Addresses 1126 Stefano Previdi (editor) 1127 Cisco Systems, Inc. 1128 Via Del Serafico, 200 1129 Rome 00142 1130 Italy 1132 Email: stefano@previdi.net 1133 Ketan Talaulikar 1134 Cisco Systems, Inc. 1135 S.No. 154/6, Phase I, Hinjawadi 1136 Pune 411 057 1137 India 1139 Email: ketant@cisco.com 1141 Clarence Filsfils 1142 Cisco Systems, Inc. 1143 Brussels 1144 Belgium 1146 Email: cfilsfil@cisco.com 1148 Hannes Gredler 1149 RtBrick Inc. 1151 Email: hannes@rtbrick.com 1153 Mach(Guoyi) Chen 1154 Huawei Technologies 1155 Huawei Building, No. 156 Beiqing Rd. 1156 Beijing 100095 1157 China 1159 Email: mach.chen@huawei.com