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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: July 29, 2018 Cisco Systems, Inc. 6 H. Gredler 7 RtBrick Inc. 8 M. Chen 9 Huawei Technologies 10 January 25, 2018 12 BGP Link-State extensions for Segment Routing 13 draft-ietf-idr-bgp-ls-segment-routing-ext-04 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 July 29, 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 . . . . . . . . . . . . . . . . . 8 74 2.2. Link Attribute TLVs . . . . . . . . . . . . . . . . . . . 9 75 2.2.1. Adjacency SID TLV . . . . . . . . . . . . . . . . . . 10 76 2.2.2. LAN Adjacency SID TLV . . . . . . . . . . . . . . . . 10 77 2.2.3. L2 Bundle Member . . . . . . . . . . . . . . . . . . 11 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 . . . . . 17 84 2.5. Equivalent OSPFv2/OSPFv3 Segment Routing TLVs/Sub-TLVs . 18 85 3. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 19 86 3.1. Advertisement of an IS-IS Prefix SID TLV . . . . . . . . 19 87 3.2. Advertisement of an OSPFv2/OSPFv3 Prefix-SID TLV . . . . 19 88 3.3. Advertisement of a range of prefix-to-SID mappings in 89 OSPF . . . . . . . . . . . . . . . . . . . . . . . . . . 19 90 3.4. Advertisement of a range of IS-IS SR bindings . . . . . . 20 91 4. Implementation Status . . . . . . . . . . . . . . . . . . . . 20 92 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 93 5.1. TLV/Sub-TLV Code Points Summary . . . . . . . . . . . . . 21 94 6. Manageability Considerations . . . . . . . . . . . . . . . . 22 95 6.1. Operational Considerations . . . . . . . . . . . . . . . 22 96 6.1.1. Operations . . . . . . . . . . . . . . . . . . . . . 22 98 7. Security Considerations . . . . . . . . . . . . . . . . . . . 22 99 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 22 100 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 22 101 9.1. Normative References . . . . . . . . . . . . . . . . . . 23 102 9.2. Informative References . . . . . . . . . . . . . . . . . 24 103 9.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 25 104 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26 106 1. Introduction 108 Segment Routing (SR) allows for a flexible definition of end-to-end 109 paths by combining sub-paths called "segments". A segment can 110 represent any instruction, topological or service-based. A segment 111 can have a local semantic to an SR node or global within a domain. 112 Within IGP topologies an SR path is encoded as a sequence of 113 topological sub-paths, called "IGP segments". These segments are 114 advertised by the link-state routing protocols (IS-IS, OSPFv2 and 115 OSPFv3). 117 Two types of IGP segments are defined, Prefix segments and Adjacency 118 segments. Prefix segments, by default, represent an ECMP-aware 119 shortest-path to a prefix, as per the state of the IGP topology. 120 Adjacency segments represent a hop over a specific adjacency between 121 two nodes in the IGP. A prefix segment is typically a multi-hop path 122 while an adjacency segment, in most of the cases, is a one-hop path. 123 [I-D.ietf-spring-segment-routing]. 125 When Segment Routing is enabled in a IGP domain, segments are 126 advertised in the form of Segment Identifiers (SIDs). The IGP link- 127 state routing protocols have been extended to advertise SIDs and 128 other SR-related information. IGP extensions are described in: IS-IS 129 [I-D.ietf-isis-segment-routing-extensions], OSPFv2 130 [I-D.ietf-ospf-segment-routing-extensions] and OSPFv3 131 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. Using these 132 extensions, Segment Routing can be enabled within an IGP domain. 134 +------------+ 135 | Consumer | 136 +------------+ 137 ^ 138 | 139 v 140 +-------------------+ 141 | BGP Speaker | +-----------+ 142 | (Route-Reflector) | | Consumer | 143 +-------------------+ +-----------+ 144 ^ ^ ^ ^ 145 | | | | 146 +---------------+ | +-------------------+ | 147 | | | | 148 v v v v 149 +-----------+ +-----------+ +-----------+ 150 | BGP | | BGP | | BGP | 151 | Speaker | | Speaker | . . . | Speaker | 152 +-----------+ +-----------+ +-----------+ 153 ^ ^ ^ 154 | | | 155 IGP IGP IGP 157 Figure 1: Link State info collection 159 Segment Routing (SR) allows advertisement of single or multi-hop 160 paths. The flooding scope for the IGP extensions for Segment routing 161 is IGP area-wide. Consequently, the contents of a Link State 162 Database (LSDB) or a Traffic Engineering Database (TED) has the scope 163 of an IGP area and therefore, by using the IGP alone it is not enough 164 to construct segments across multiple IGP Area or AS boundaries. 166 In order to address the need for applications that require 167 topological visibility across IGP areas, or even across Autonomous 168 Systems (AS), the BGP-LS address-family/sub-address-family have been 169 defined to allow BGP to carry Link-State information. The BGP 170 Network Layer Reachability Information (NLRI) encoding format for 171 BGP-LS and a new BGP Path Attribute called the BGP-LS attribute are 172 defined in [RFC7752]. The identifying key of each Link-State object, 173 namely a node, link, or prefix, is encoded in the NLRI and the 174 properties of the object are encoded in the BGP-LS attribute. 175 Figure 1 describes a typical deployment scenario. In each IGP area, 176 one or more nodes are configured with BGP-LS. These BGP speakers 177 form an IBGP mesh by connecting to one or more route-reflectors. 178 This way, all BGP speakers (specifically the route-reflectors) obtain 179 Link-State information from all IGP areas (and from other ASes from 180 EBGP peers). An external component connects to the route-reflector 181 to obtain this information (perhaps moderated by a policy regarding 182 what information is or isn't advertised to the external component). 184 This document describes extensions to BGP-LS to advertise the SR 185 information. An external component (e.g., a controller) then can 186 collect SR information in the "northbound" direction across IGP areas 187 or ASes and construct the end-to-end path (with its associated SIDs) 188 that need to be applied to an incoming packet to achieve the desired 189 end-to-end forwarding. 191 2. BGP-LS Extensions for Segment Routing 193 This document defines SR extensions to BGP-LS and specifies the TLVs 194 and sub-TLVs for advertising SR information. Section 2.4 and 195 Section 2.5 illustrates the equivalent TLVs and sub-TLVs in IS-IS, 196 OSPFv2 and OSPFv3 protocols. 198 BGP-LS [RFC7752] defines the BGP-LS NLRI that can be a Node NLRI, a 199 Link NLRI or a Prefix NLRI. The corresponding BGP-LS attribute is a 200 Node Attribute, a Link Attribute or a Prefix Attribute. BGP-LS 201 [RFC7752] defines the TLVs that map link-state information to BGP-LS 202 NLRI and the BGP-LS attribute. This document adds additional BGP-LS 203 attribute TLVs in order to encode SR information. 205 2.1. Node Attributes TLVs 207 The following Node Attribute TLVs are defined: 209 +-----------------+----------+---------------+ 210 | Description | Length | Section | 211 +-----------------+----------+---------------+ 212 | SID/Label | variable | Section 2.1.1 | 213 | SR Capabilities | variable | Section 2.1.2 | 214 | SR Algorithm | variable | Section 2.1.3 | 215 | SR Local Block | variable | Section 2.1.4 | 216 | SRMS Preference | variable | Section 2.1.5 | 217 +-----------------+----------+---------------+ 219 Table 1: Node Attribute TLVs 221 These TLVs can ONLY be added to the Node Attribute associated with 222 the Node NLRI that originates the corresponding SR TLV. 224 2.1.1. SID/Label Sub-TLV 226 The SID/Label TLV is used as sub-TLV by the SR-Capabilities 227 (Section 2.1.2) and SRLB (Section 2.1.4) TLVs and has the following 228 format: 230 0 1 2 3 231 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 1 232 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 233 | Type | Length | 234 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 235 | SID/Label (variable) | 236 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 238 where: 240 Type: TBD, see Section 5. 242 Length: Variable, 3 or 4 bytes 244 SID/Label: If length is set to 3, then the 20 rightmost bits 245 represent a label. If length is set to 4, then the value 246 represents a 32 bit SID. 248 The receiving router MUST ignore the SID/Label sub-TLV if the 249 length is other then 3 or 4. 251 2.1.2. SR-Capabilities TLV 253 The SR-Capabilities TLV is used in order to advertise the node's SR 254 Capabilities and its Segment Routing Global Base (SRGB) range(s). 255 This information is derived from the protocol specific 256 advertisements. 258 o IS-IS, as defined by the SR-Capabilities TLV in 259 [I-D.ietf-isis-segment-routing-extensions]. 261 o OSPFv2/OSPFv3, as defined by the SID/Label Range TLV in 262 [I-D.ietf-ospf-segment-routing-extensions] and 263 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 265 The SR Capabilities TLV has following format: 267 0 1 2 3 268 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 1 269 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 270 | Type | Length | 271 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 272 | Flags | RESERVED | 273 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 275 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 276 | Range Size | 277 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 278 // SID/Label sub-TLV (variable) // 279 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 281 Type: TBD, see Section 5. 283 Length: Variable. 285 Flags: 1 octet of flags as defined in 286 [I-D.ietf-isis-segment-routing-extensions]. 288 One or more entries, each of which have the following format: 290 Range Size: 3 octet value indicating the number of labels in 291 the range. 293 SID/Label sub-TLV (as defined in Section 2.1.1). 295 2.1.3. SR-Algorithm TLV 297 The SR-Algorithm TLV has the following format: 299 0 1 2 3 300 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 1 301 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 302 | Type | Length | 303 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 304 | Algorithm 1 | Algorithm... | Algorithm N | | 305 +- -+ 306 | | 307 + + 309 where: 311 Type: TBD, see Section 5. 313 Length: Variable. 315 Algorithm: 1 octet identifying the algorithm. 317 2.1.4. SR Local Block TLV 319 The SR Local Block (SRLB) TLV contains the range(s) of labels the 320 node has reserved for local SIDs. Local SIDs are used, e.g., in IGP 321 (IS-IS, OSPF) for Adjacency-SIDs, and may also be allocated by 322 components other than IGP protocols. As an example, an application 323 or a controller may instruct a node to allocate a specific local SID. 324 Therefore, in order for such applications or controllers to know the 325 range of local SIDs available, it is required that the node 326 advertises its SRLB. 328 The SRLB TLV has the following format: 330 0 1 2 3 331 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 1 332 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 333 | Type | Length | 334 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 335 | Flags | RESERVED | 336 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 338 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 339 | Range Size | 340 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 341 // SID/Label sub-TLV (variable) // 342 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 344 Type: TBD, see Section 5. 346 Length: Variable. 348 Flags: 1 octet of flags. None are defined at this stage. 350 One or more entries, each of which have the following format: 352 Range Size: 3 octet value indicating the number of labels in 353 the range. 355 SID/Label sub-TLV (as defined in Section 2.1.1). 357 2.1.5. SRMS Preference TLV 359 The Segment Routing Mapping Server (SRMS) Preference TLV is used in 360 order to associate a preference with SRMS advertisements from a 361 particular source. 363 The SRMS Preference TLV has following format: 365 0 1 2 3 366 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 1 367 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 368 | Type | Length | 369 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 370 | Preference | 371 +-+-+-+-+-+-+-+-+ 373 Type: TBD, see Section 5. 375 Length: 1. 377 Preference: 1 octet. Unsigned 8 bit SRMS preference. 379 The use of the SRMS Preference TLV is defined in 380 [I-D.ietf-isis-segment-routing-extensions], 381 [I-D.ietf-ospf-segment-routing-extensions] and 382 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 384 2.2. Link Attribute TLVs 386 The following Link Attribute TLVs are are defined: 388 +----------------------------------------+----------+---------------+ 389 | Description | Length | Section | 390 +----------------------------------------+----------+---------------+ 391 | Adjacency Segment Identifier (Adj-SID) | variable | Section 2.2.1 | 392 | TLV | | | 393 | LAN Adjacency Segment Identifier (Adj- | variable | Section 2.2.2 | 394 | SID) TLV | | | 395 | L2 Bundle Member TLV | variable | Section 2.2.3 | 396 +----------------------------------------+----------+---------------+ 398 Table 2: Link Attribute TLVs 400 These TLVs can ONLY be added to the Link Attribute associated with 401 the link whose local node originates the corresponding TLV. 403 For a LAN, normally a node only announces its adjacency to the IS-IS 404 pseudo-node (or the equivalent OSPF Designated and Backup Designated 405 Routers)[I-D.ietf-isis-segment-routing-extensions]. The LAN 406 Adjecency Segment TLV allows a node to announce adjacencies to all 407 other nodes attached to the LAN in a single instance of the BGP-LS 408 Link NLRI. Without this TLV, the corresponding BGP-LS link NLRI 409 would need to be originated for each additional adjacency in order to 410 advertise the SR TLVs for these neighbor adjacencies. 412 2.2.1. Adjacency SID TLV 414 The Adjacency SID (Adj-SID) TLV has the following format: 416 0 1 2 3 417 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 1 418 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 419 | Type | Length | 420 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 421 | Flags | Weight | Reserved | 422 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 423 | SID/Label/Index (variable) | 424 +---------------------------------------------------------------+ 426 where: 428 Type: TBD, see Section 5. 430 Length: Variable. 432 Flags. 1 octet field of following flags as defined in 433 [I-D.ietf-isis-segment-routing-extensions], 434 [I-D.ietf-ospf-segment-routing-extensions] and 435 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 437 Weight: Weight used for load-balancing purposes. 439 SID/Index/Label: Label or index value depending on the flags 440 setting as defined in [I-D.ietf-isis-segment-routing-extensions], 441 [I-D.ietf-ospf-segment-routing-extensions] and 442 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 444 2.2.2. LAN Adjacency SID TLV 446 The LAN Adjacency SID (LAN-Adj-SID-SID) TLV has the following format: 448 0 1 2 3 449 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 1 450 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 451 | Type | Length | 452 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 453 | Flags | Weight | Reserved | 454 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 456 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 457 | OSPF Neighbor ID / IS-IS System-ID | 458 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 459 | | 460 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 462 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 463 | SID/Label/Index (variable) | 464 +---------------------------------------------------------------+ 466 where: 468 Type: TBD, see Section 5. 470 Length: Variable. 472 Flags. 1 octet field of following flags as defined in 473 [I-D.ietf-isis-segment-routing-extensions], 474 [I-D.ietf-ospf-segment-routing-extensions] and 475 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 477 Weight: Weight used for load-balancing purposes. 479 SID/Index/Label: Label or index value depending on the flags 480 setting as defined in [I-D.ietf-isis-segment-routing-extensions], 481 [I-D.ietf-ospf-segment-routing-extensions] and 482 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 484 2.2.3. L2 Bundle Member 486 The L2 Bundle Member Attribute TLV identifies an L2 Bundle Member 487 link which in turn is associated with a parent L3 link. The L3 link 488 is described by the Link NLRI defined in [RFC7752] and the L2 Bundle 489 Member Attribute TLV is associated with the Link NLRI. The TLV MAY 490 include sub-TLVs which describe attributes associated with the bundle 491 member. The identified bundle member represents a unidirectional 492 path from the originating router to the neighbor specified in the 493 parent L3 Link. Multiple L2 Bundle Member Attribute TLVs MAY be 494 associated with a Link NLRI. 496 The L2 Bundle Member Attribute TLV has the following format: 498 0 1 2 3 499 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 1 500 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 501 | Type | Length | 502 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 504 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 505 | L2 Bundle Member Descriptor | 506 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 507 // Link attribute sub-TLVs(variable) // 508 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 510 where: 512 Type: TBD, see Section 5. 514 Length: Variable. 516 L2 Bundle Member Descriptor: A Link Local Identifier as defined in 517 [RFC4202]. 519 Link attributes for L2 Bundle Member Links are advertised as sub-TLVs 520 of the L2Bundle Member Attribute TLV. The sub-TLVs are identical to 521 existing BGP-LS TLVs as identified in the table below. 523 +-----------+----------------------------+--------------------------+ 524 | TLV Code | Description | Reference Document | 525 | Point | | | 526 +-----------+----------------------------+--------------------------+ 527 | 1088 | Administrative group | [RFC7752] | 528 | | (color) | | 529 | 1089 | Maximum link bandwidth | [RFC7752] | 530 | 1090 | Max. reservable link | [RFC7752] | 531 | | bandwidth | | 532 | 1091 | Unreserved bandwidth | [RFC7752] | 533 | 1092 | TE default metric | [RFC7752] | 534 | 1093 | Link protection type | [RFC7752] | 535 | 1099 | Adjacency Segment | Section 2.2.1 | 536 | | Identifier (Adj-SID) TLV | | 537 | 1100 | LAN Adjacency Segment | Section 2.2.2 | 538 | | Identifier (Adj-SID) TLV | | 539 | 1104 | Unidirectional link delay | [I-D.ietf-idr-te-pm-bgp] | 540 | 1105 | Min/Max Unidirectional | [I-D.ietf-idr-te-pm-bgp] | 541 | | link delay | | 542 | 1106 | Min/Max Unidirectional | [I-D.ietf-idr-te-pm-bgp] | 543 | | link delay | | 544 | 1107 | Unidirectional packet loss | [I-D.ietf-idr-te-pm-bgp] | 545 | 1108 | Unidirectional residual | [I-D.ietf-idr-te-pm-bgp] | 546 | | bandwidth | | 547 | 1109 | Unidirectional available | [I-D.ietf-idr-te-pm-bgp] | 548 | | bandwidth | | 549 | 1110 | Unidirectional bandwidth | [I-D.ietf-idr-te-pm-bgp] | 550 | | utilization | | 551 +-----------+----------------------------+--------------------------+ 553 Table 3: L2 Bundle Member Link Attribute TLVs 555 2.3. Prefix Attribute TLVs 557 The following Prefix Attribute TLVs are defined: 559 +------------------------+----------+---------------+ 560 | Description | Length | Section | 561 +------------------------+----------+---------------+ 562 | Prefix SID | variable | Section 2.3.1 | 563 | Range | variable | Section 2.3.4 | 564 | Prefix Attribute Flags | variable | Section 2.3.2 | 565 | Source Router-ID | variable | Section 2.3.3 | 566 +------------------------+----------+---------------+ 568 Table 4: Prefix Attribute TLVs 570 2.3.1. Prefix-SID TLV 572 The Prefix-SID TLV can ONLY be added to the Prefix Attribute whose 573 local node in the corresponding Prefix NLRI is the node that 574 originates the corresponding SR TLV. 576 The Prefix-SID TLV is used in order to advertise information related 577 to a Prefix-SID. This information is originated in: 579 o IS-IS, as defined by the Prefix-SID TLV in 580 [I-D.ietf-isis-segment-routing-extensions]. 582 o OSPFv2/OSPFv3, as defined by the Prefix-SID TLV in 583 [I-D.ietf-ospf-segment-routing-extensions] and 584 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. 586 The Prefix-SID has the following format: 588 0 1 2 3 589 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 1 590 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 591 | Type | Length | 592 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 593 | Flags | Algorithm | Reserved | 594 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 595 | SID/Index/Label (variable) | 596 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 598 where: 600 Type: TBD, see Section 5. 602 Length: Variable 604 Algorithm: 1 octet value identify the algorithm. 606 SID/Index/Label: 608 * IS-IS: Label or index value as defined in 609 [I-D.ietf-isis-segment-routing-extensions], 611 * OSPFv2: Label or index value as defined in 612 [I-D.ietf-ospf-segment-routing-extensions], 614 * OSPFv3: Label or index value as defined in 615 [I-D.ietf-ospf-ospfv3-segment-routing-extensions], 617 The Prefix-SID TLV includes a Flags field. In the context of BGP-LS, 618 the Flags field format and the semantic of each individual flag MUST 619 be taken from the corresponding source protocol (i.e.: the protocol 620 of origin of the Prefix-SID being advertised in BGP-LS). 622 IS-IS Prefix-SID flags are defined in 623 [I-D.ietf-isis-segment-routing-extensions] section 2.1. 625 OSPFv2 Prefix-SID flags are defined in 626 [I-D.ietf-ospf-segment-routing-extensions] section 5. 628 OSPFv3 Prefix-SID flags are defined in 629 [I-D.ietf-ospf-segment-routing-extensions] section 5. 631 2.3.2. Prefix Attribute Flags TLV 633 The Prefix Attribute Flags TLV carries IPv4/IPv6 prefix attribute 634 flags information. These flags are defined for OSPFv2 in [RFC7684], 635 for OSPFv3 in [RFC5340] and for ISIS in [RFC7794]. 637 The Prefix Attribute Flags TLV has the following format: 639 0 1 2 3 640 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 1 641 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 642 | Type | Length | 643 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 644 // Flags (variable) // 645 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 647 where: 649 Type: TBD, see Section 5. 651 Length: variable. 653 Flags: a variable length flag field (according to the length 654 field). Flags are routing protocol specific. OSPFv2 flags are 655 defined in [RFC7684], for OSPFv3 this maps to the Prefix Options 656 field defined in [RFC5340] and IS-IS flags are defined in 657 [RFC7794]. The receiver of the BGP-LS update, when inspecting the 658 Prefix Attribute Flags TLV, MUST check the Protocol-ID of the NLRI 659 and refer to the protocol specification in order to parse the 660 flags. 662 2.3.3. Source Router Identifier (Source Router-ID) TLV 664 The Source Router-ID TLV contains the IPv4 or IPv6 Router-ID of the 665 originator of the Prefix. For IS-IS protocol this is as defined in 666 [RFC7794]. The Source Router-ID TLV may be used to carry the OSPF 667 Router-ID of the prefix originator. 669 The Source Router-ID TLV has the following format: 671 0 1 2 3 672 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 1 673 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 674 | Type | Length | 675 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 676 // IPv4/IPv6 Address (Router-ID) // 677 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 679 where: 681 Type: TBD, see Section 5. 683 Length: 4 or 16. 685 IPv4/IPv6 Address: 4 octet IPv4 address or 16 octet IPv6 address. 687 The semantic of the Source Router-ID TLV is defined in [RFC7794]. 689 2.3.4. Range TLV 691 The Range TLV can ONLY be added to the Prefix Attribute whose local 692 node in the corresponding Prefix NLRI is the node that originates the 693 corresponding SR TLV. 695 When the range TLV is used in order to advertise a range of prefix- 696 to-SID mappings as defined in 697 [I-D.ietf-ospf-segment-routing-extensions], 698 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]and 699 [I-D.ietf-isis-segment-routing-extensions]. The Prefix-NLRI the 700 Range TLV is attached to MUST be advertised as a non-routing prefix 701 where no IGP metric TLV (TLV 1095) is attached. 703 The format of the Range TLV is as follows: 705 0 1 2 3 706 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 1 707 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 708 | Type | Length | 709 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 710 | Flags | RESERVED | Range Size | 711 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 712 // sub-TLVs // 713 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 715 where: 717 Figure 2: Range TLV format 719 Type: TBD, see Section 5. 721 Length is 4. 723 Flags: as defined in [I-D.ietf-ospf-segment-routing-extensions], 724 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] and 725 [I-D.ietf-isis-segment-routing-extensions]. 727 Range Size: 2 octets as defined in 728 [I-D.ietf-ospf-segment-routing-extensions]. 730 Within the Range TLV, the Prefix-SID TLV (used as sub-TLV in this 731 context) MAY be present. 733 2.4. Equivalent IS-IS Segment Routing TLVs/Sub-TLVs 735 This section illustrate the IS-IS Segment Routing Extensions TLVs and 736 sub-TLVs mapped to the ones defined in this document. 738 The following table, illustrates for each BGP-LS TLV, its equivalence 739 in IS-IS. 741 +----------------------------------------+----------+---------------+ 742 | Description | Length | IS-IS TLV | 743 | | | /sub-TLV | 744 +----------------------------------------+----------+---------------+ 745 | SR Capabilities | variable | 2 [1] | 746 | SR Algorithm | variable | 19 [2] | 747 | Adjacency Segment Identifier (Adj-SID) | variable | 31 [3] | 748 | TLV | | | 749 | LAN Adjacency Segment Identifier (LAN- | variable | 32 [4] | 750 | Adj-SID) TLV | | | 751 | Prefix SID | variable | 3 [5] | 752 | SID/Label TLV | variable | 1 [6] | 753 | Prefix Attribute Flags | variable | 4 [7] | 754 | Source Router ID | variable | 11/12 [8] | 755 | L2 Bundle Member TLV | variable | 25 [9] | 756 +----------------------------------------+----------+---------------+ 758 Table 5: IS-IS Segment Routing Extensions TLVs/Sub-TLVs 760 2.5. Equivalent OSPFv2/OSPFv3 Segment Routing TLVs/Sub-TLVs 762 This section illustrate the OSPFv2 and OSPFv3 Segment Routing 763 Extensions TLVs and sub-TLVs mapped to the ones defined in this 764 document. 766 The following table, illustrates for each BGP-LS TLV, its equivalence 767 in OSPFv2 and OSPFv3. 769 +--------------------------------------+----------+-----------------+ 770 | Description | Length | OSPFv2 TLV/sub- | 771 | | | TLV | 772 +--------------------------------------+----------+-----------------+ 773 | SR Capabilities | variable | 9 [10] | 774 | SR Algorithm | variable | 8 [11] | 775 | Adjacency Segment Identifier (Adj- | variable | 2 [12] | 776 | SID) TLV | | | 777 | LAN Adjacency Segment Identifier | variable | 3 [13] | 778 | (Adj-SID) TLV | | | 779 | Prefix SID | variable | 2 [14] | 780 | SID/Label TLV | variable | 1 [15] | 781 | Prefix Attribute Flags | variable | 4 [16] | 782 +--------------------------------------+----------+-----------------+ 784 Table 6: OSPF Segment Routing Extensions TLVs/Sub-TLVs 786 +--------------------------------------+----------+-----------------+ 787 | Description | Length | OSPFv3 TLV/sub- | 788 | | | TLV | 789 +--------------------------------------+----------+-----------------+ 790 | SR Capabilities | variable | 9 [17] | 791 | SR Algorithm | variable | 8 [18] | 792 | Adjacency Segment Identifier (Adj- | variable | 5 [19] | 793 | SID) TLV | | | 794 | LAN Adjacency Segment Identifier | variable | 6 [20] | 795 | (Adj-SID) TLV | | | 796 | Prefix SID | variable | 4 [21] | 797 | SID/Label TLV | variable | 3 [22] | 798 | Prefix Attribute Flags | variable | 4 [23] | 799 +--------------------------------------+----------+-----------------+ 801 Table 7: OSPFv3 Segment Routing Extensions TLVs/Sub-TLVs 803 3. Procedures 805 The following sections describe the different operations for the 806 propagation of SR TLVs into BGP-LS from OSPFv2, OSPFv3 and ISIS 807 protocols. 809 3.1. Advertisement of an IS-IS Prefix SID TLV 811 The advertisement of an IS-IS Prefix SID TLV has following rules: 813 The IS-IS Prefix-SID is encoded in the BGP-LS Prefix Attribute 814 Prefix-SID as defined in Section 2.3.1. The flags in the Prefix- 815 SID TLV have the semantic defined in 816 [I-D.ietf-isis-segment-routing-extensions] section 2.1. 818 3.2. Advertisement of an OSPFv2/OSPFv3 Prefix-SID TLV 820 The advertisement of an OSPFv2/OSPFv3 Prefix-SID TLV has following 821 rules: 823 The OSPFv2/OSPFv3 Prefix-SID is encoded in the BGP-LS Prefix 824 Attribute Prefix-SID as defined in Section 2.3.1. The flags in 825 the Prefix-SID TLV have the semantic defined in 826 [I-D.ietf-ospf-segment-routing-extensions] section 5 or 827 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] section 5. 829 3.3. Advertisement of a range of prefix-to-SID mappings in OSPF 831 The advertisement of a range of prefix-to-SID mappings in OSPF has 832 following rules: 834 The OSPFv2/OSPFv3 Extended Prefix Range TLV is encoded in the BGP- 835 LS Prefix Attribute Range TLV as defined in Section 2.3.4. The 836 flags of the Range TLV have the semantic mapped to the definition 837 in [I-D.ietf-ospf-segment-routing-extensions] section 4 or 838 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] section 4. The 839 Prefix-SID from the original OSPF Prefix SID sub-TLV is encoded 840 using the BGP-LS Prefix Attribute Prefix-SID as defined in 841 Section 2.3.1 with the flags set according to the definition in 842 [I-D.ietf-ospf-segment-routing-extensions] section 5 or 843 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] section 5. 845 3.4. Advertisement of a range of IS-IS SR bindings 847 The advertisement of a range of IS-IS Mapping Server bindings 848 ([I-D.ietf-isis-segment-routing-extensions]) is encoded using the 849 following TLV/sub-TLV structure: 851 Range TLV 852 Prefix-SID TLV (used as a sub-TLV in this context) 854 where: 856 o The Range TLV is defined in Section 2.3.4. 858 o The Prefix-SID TLV (used as sub-TLV in this context) is defined in 859 Section 2.3.1. 861 4. Implementation Status 863 Note to RFC Editor: Please remove this section prior to publication, 864 as well as the reference to RFC 7942. 866 This section records the status of known implementations of the 867 protocol defined by this specification at the time of posting of this 868 Internet-Draft, and is based on a proposal described in [RFC7942]. 869 The description of implementations in this section is intended to 870 assist the IETF in its decision processes in progressing drafts to 871 RFCs. Please note that the listing of any individual implementation 872 here does not imply endorsement by the IETF. Furthermore, no effort 873 has been spent to verify the information presented here that was 874 supplied by IETF contributors. This is not intended as, and must not 875 be construed to be, a catalog of available implementations or their 876 features. Readers are advised to note that other implementations may 877 exist. 879 According to [RFC7942], "this will allow reviewers and working groups 880 to assign due consideration to documents that have the benefit of 881 running code, which may serve as evidence of valuable experimentation 882 and feedback that have made the implemented protocols more mature. 883 It is up to the individual working groups to use this information as 884 they see fit". 886 Several early implementations exist and will be reported in detail in 887 a forthcoming version of this document. For purposes of early 888 interoperability testing, when no FCFS code point was available, 889 implementations have made use of the values described in Table 8. 891 It will ease implementation interoperability and deployment if the 892 value could be preserved also due to the large amount of codepoints 893 this draft requires. However, when IANA-assigned values are 894 available, implementations will be updated to use them. 896 5. IANA Considerations 898 This document requests assigning code-points from the registry "BGP- 899 LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute 900 TLVs" based on table Table 8. The column "IS-IS TLV/Sub-TLV" defined 901 in the registry does not require any value and should be left empty. 903 5.1. TLV/Sub-TLV Code Points Summary 905 This section contains the global table of all TLVs/sub-TLVs defined 906 in this document. 908 +-------------+-------------------------------------+---------------+ 909 | TLV Code | Description | Reference | 910 | Point | | | 911 +-------------+-------------------------------------+---------------+ 912 | 1034 | SR Capabilities | Section 2.1.2 | 913 | 1035 | SR Algorithm | Section 2.1.3 | 914 | 1036 | SR Local Block | Section 2.1.4 | 915 | 1037 | SRMS Preference | Section 2.1.5 | 916 | 1099 | Adjacency Segment Identifier (Adj- | Section 2.2.1 | 917 | | SID) TLV | | 918 | 1100 | LAN Adjacency Segment Identifier | Section 2.2.2 | 919 | | (Adj-SID) TLV | | 920 | 1158 | Prefix SID | Section 2.3.1 | 921 | 1159 | Range | Section 2.3.4 | 922 | 1161 | SID/Label TLV | Section 2.1.1 | 923 | 1170 | Prefix Attribute Flags | Section 2.3.2 | 924 | 1171 | Source Router-ID | Section 2.3.3 | 925 | 1172 | L2 Bundle Member TLV | Section 2.2.3 | 926 +-------------+-------------------------------------+---------------+ 928 Table 8: Summary Table of TLV/Sub-TLV Codepoints 930 6. Manageability Considerations 932 This section is structured as recommended in [RFC5706]. 934 6.1. Operational Considerations 936 6.1.1. Operations 938 Existing BGP and BGP-LS operational procedures apply. No additional 939 operation procedures are defined in this document. 941 7. Security Considerations 943 Procedures and protocol extensions defined in this document do not 944 affect the BGP security model. See the 'Security Considerations' 945 section of [RFC4271] for a discussion of BGP security. Also refer to 946 [RFC4272] and [RFC6952] for analysis of security issues for BGP. 948 8. Contributors 950 The following people have substantially contributed to the editing of 951 this document: 953 Peter Psenak 954 Cisco Systems 955 Email: ppsenak@cisco.com 957 Les Ginsberg 958 Cisco Systems 959 Email: ginsberg@cisco.com 961 Acee Lindem 962 Cisco Systems 963 Email: acee@cisco.com 965 Saikat Ray 966 Individual 967 Email: raysaikat@gmail.com 969 Jeff Tantsura 970 Nuage Networks 971 Email: jefftant.ietf@gmail.com 973 9. References 974 9.1. Normative References 976 [I-D.ietf-idr-te-pm-bgp] 977 Ginsberg, L., Previdi, S., Wu, Q., Gredler, H., Ray, S., 978 Tantsura, J., and C. Filsfils, "BGP-LS Advertisement of 979 IGP Traffic Engineering Performance Metric Extensions", 980 draft-ietf-idr-te-pm-bgp-08 (work in progress), August 981 2017. 983 [I-D.ietf-isis-segment-routing-extensions] 984 Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A., 985 Gredler, H., Litkowski, S., Decraene, B., and J. Tantsura, 986 "IS-IS Extensions for Segment Routing", draft-ietf-isis- 987 segment-routing-extensions-15 (work in progress), December 988 2017. 990 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] 991 Psenak, P., Previdi, S., Filsfils, C., Gredler, H., 992 Shakir, R., Henderickx, W., and J. Tantsura, "OSPFv3 993 Extensions for Segment Routing", draft-ietf-ospf-ospfv3- 994 segment-routing-extensions-10 (work in progress), 995 September 2017. 997 [I-D.ietf-ospf-segment-routing-extensions] 998 Psenak, P., Previdi, S., Filsfils, C., Gredler, H., 999 Shakir, R., Henderickx, W., and J. Tantsura, "OSPF 1000 Extensions for Segment Routing", draft-ietf-ospf-segment- 1001 routing-extensions-24 (work in progress), December 2017. 1003 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1004 Requirement Levels", BCP 14, RFC 2119, 1005 DOI 10.17487/RFC2119, March 1997, 1006 . 1008 [RFC4202] Kompella, K., Ed. and Y. Rekhter, Ed., "Routing Extensions 1009 in Support of Generalized Multi-Protocol Label Switching 1010 (GMPLS)", RFC 4202, DOI 10.17487/RFC4202, October 2005, 1011 . 1013 [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A 1014 Border Gateway Protocol 4 (BGP-4)", RFC 4271, 1015 DOI 10.17487/RFC4271, January 2006, 1016 . 1018 [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF 1019 for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, 1020 . 1022 [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., 1023 Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute 1024 Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 1025 2015, . 1027 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 1028 S. Ray, "North-Bound Distribution of Link-State and 1029 Traffic Engineering (TE) Information Using BGP", RFC 7752, 1030 DOI 10.17487/RFC7752, March 2016, 1031 . 1033 [RFC7794] Ginsberg, L., Ed., Decraene, B., Previdi, S., Xu, X., and 1034 U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4 1035 and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794, 1036 March 2016, . 1038 9.2. Informative References 1040 [I-D.ietf-spring-segment-routing] 1041 Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B., 1042 Litkowski, S., and R. Shakir, "Segment Routing 1043 Architecture", draft-ietf-spring-segment-routing-15 (work 1044 in progress), January 2018. 1046 [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", 1047 RFC 4272, DOI 10.17487/RFC4272, January 2006, 1048 . 1050 [RFC5706] Harrington, D., "Guidelines for Considering Operations and 1051 Management of New Protocols and Protocol Extensions", 1052 RFC 5706, DOI 10.17487/RFC5706, November 2009, 1053 . 1055 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 1056 BGP, LDP, PCEP, and MSDP Issues According to the Keying 1057 and Authentication for Routing Protocols (KARP) Design 1058 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 1059 . 1061 [RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running 1062 Code: The Implementation Status Section", BCP 205, 1063 RFC 7942, DOI 10.17487/RFC7942, July 2016, 1064 . 1066 9.3. URIs 1068 [1] http://tools.ietf.org/html/draft-ietf-isis-segment-routing- 1069 extensions-05#section-3.1 1071 [2] http://tools.ietf.org/html/draft-ietf-isis-segment-routing- 1072 extensions-05#section-3.2 1074 [3] http://tools.ietf.org/html/draft-ietf-isis-segment-routing- 1075 extensions-05#section-2.2.1 1077 [4] http://tools.ietf.org/html/draft-ietf-isis-segment-routing- 1078 extensions-05#section-2.2.2 1080 [5] http://tools.ietf.org/html/draft-ietf-isis-segment-routing- 1081 extensions-05#section-2.1 1083 [6] http://tools.ietf.org/html/draft-ietf-isis-segment-routing- 1084 extensions-05#section-2.3 1086 [7] http://tools.ietf.org/html/RFC7794 1088 [8] http://tools.ietf.org/html/RFC7794 1090 [9] http://tools.ietf.org/html/draft-ietf-isis-l2bundles-05 1092 [10] http://tools.ietf.org/html/draft-ietf-ospf-segment-routing- 1093 extensions-05#section-3.2 1095 [11] http://tools.ietf.org/html/draft-ietf-ospf-segment-routing- 1096 extensions-05#section-3.1 1098 [12] http://tools.ietf.org/html/draft-ietf-ospf-segment-routing- 1099 extensions-05#section-7.1 1101 [13] http://tools.ietf.org/html/draft-ietf-ospf-segment-routing- 1102 extensions-05#section-7.2 1104 [14] http://tools.ietf.org/html/draft-ietf-ospf-segment-routing- 1105 extensions-05#section-5 1107 [15] http://tools.ietf.org/html/draft-ietf-ospf-segment-routing- 1108 extensions-05#section-2.1 1110 [16] http://tools.ietf.org/html/RFC7684#section-2.1 1112 [17] http://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment- 1113 routing-extensions-05#section-3.2 1115 [18] http://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment- 1116 routing-extensions-05#section-3.1 1118 [19] http://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment- 1119 routing-extensions-05#section-7.1 1121 [20] http://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment- 1122 routing-extensions-05#section-7.2 1124 [21] http://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment- 1125 routing-extensions-05#section-5 1127 [22] http://tools.ietf.org/html/draft-ietf-ospf-ospfv3-segment- 1128 routing-extensions-05#section-2.1 1130 [23] http://tools.ietf.org/html/RFC5340#section-A.4.1.1 1132 Authors' Addresses 1134 Stefano Previdi (editor) 1135 Cisco Systems, Inc. 1136 Via Del Serafico, 200 1137 Rome 00142 1138 Italy 1140 Email: stefano@previdi.net 1142 Ketan Talaulikar 1143 Cisco Systems, Inc. 1144 S.No. 154/6, Phase I, Hinjawadi 1145 Pune 411 057 1146 India 1148 Email: ketant@cisco.com 1150 Clarence Filsfils 1151 Cisco Systems, Inc. 1152 Brussels 1153 Belgium 1155 Email: cfilsfil@cisco.com 1156 Hannes Gredler 1157 RtBrick Inc. 1159 Email: hannes@rtbrick.com 1161 Mach(Guoyi) Chen 1162 Huawei Technologies 1163 Huawei Building, No. 156 Beiqing Rd. 1164 Beijing 100095 1165 China 1167 Email: mach.chen@huawei.com