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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Open Shortest Path First IGP P. Psenak, Ed. 3 Internet-Draft Cisco Systems, Inc. 4 Intended status: Standards Track S. Previdi, Ed. 5 Expires: May 9, 2019 Individual 6 November 5, 2018 8 OSPFv3 Extensions for Segment Routing 9 draft-ietf-ospf-ospfv3-segment-routing-extensions-17 11 Abstract 13 Segment Routing (SR) allows a flexible definition of end-to-end paths 14 within IGP topologies by encoding paths as sequences of topological 15 sub-paths, called "segments". These segments are advertised by the 16 link-state routing protocols (IS-IS and OSPF). 18 This draft describes the OSPFv3 extensions required for Segment 19 Routing with MPLS data plane. 21 Requirements Language 23 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 24 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 25 document are to be interpreted as described in [RFC2119]. 27 Status of This Memo 29 This Internet-Draft is submitted in full conformance with the 30 provisions of BCP 78 and BCP 79. 32 Internet-Drafts are working documents of the Internet Engineering 33 Task Force (IETF). Note that other groups may also distribute 34 working documents as Internet-Drafts. The list of current Internet- 35 Drafts is at https://datatracker.ietf.org/drafts/current/. 37 Internet-Drafts are draft documents valid for a maximum of six months 38 and may be updated, replaced, or obsoleted by other documents at any 39 time. It is inappropriate to use Internet-Drafts as reference 40 material or to cite them other than as "work in progress." 42 This Internet-Draft will expire on May 9, 2019. 44 Copyright Notice 46 Copyright (c) 2018 IETF Trust and the persons identified as the 47 document authors. All rights reserved. 49 This document is subject to BCP 78 and the IETF Trust's Legal 50 Provisions Relating to IETF Documents 51 (https://trustee.ietf.org/license-info) in effect on the date of 52 publication of this document. Please review these documents 53 carefully, as they describe your rights and restrictions with respect 54 to this document. Code Components extracted from this document must 55 include Simplified BSD License text as described in Section 4.e of 56 the Trust Legal Provisions and are provided without warranty as 57 described in the Simplified BSD License. 59 Table of Contents 61 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 62 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 63 3. Segment Routing Identifiers . . . . . . . . . . . . . . . . . 4 64 3.1. SID/Label Sub-TLV . . . . . . . . . . . . . . . . . . . . 4 65 4. Segment Routing Capabilities . . . . . . . . . . . . . . . . 5 66 4.1. SR-Algorithm TLV . . . . . . . . . . . . . . . . . . . . 5 67 4.2. SID/Label Range TLV . . . . . . . . . . . . . . . . . . . 6 68 4.3. SR Local Block TLV . . . . . . . . . . . . . . . . . . . 8 69 4.4. SRMS Preference TLV . . . . . . . . . . . . . . . . . . . 10 70 5. OSPFv3 Extended Prefix Range TLV . . . . . . . . . . . . . . 11 71 6. Prefix SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 14 72 7. Adjacency Segment Identifier (Adj-SID) . . . . . . . . . . . 17 73 7.1. Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 18 74 7.2. LAN Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . 19 75 8. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 20 76 8.1. Intra-area Segment routing in OSPFv3 . . . . . . . . . . 20 77 8.2. Inter-area Segment routing in OSPFv3 . . . . . . . . . . 21 78 8.3. Segment Routing for External Prefixes . . . . . . . . . . 22 79 8.4. Advertisement of Adj-SID . . . . . . . . . . . . . . . . 23 80 8.4.1. Advertisement of Adj-SID on Point-to-Point Links . . 23 81 8.4.2. Adjacency SID on Broadcast or NBMA Interfaces . . . . 23 82 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23 83 9.1. OSPFv3 Extended-LSA TLV Registry . . . . . . . . . . . . 23 84 9.2. OSPFv3 Extended-LSA Sub-TLV registry . . . . . . . . . . 24 85 10. Security Considerations . . . . . . . . . . . . . . . . . . . 24 86 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 24 87 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 25 88 12.1. Normative References . . . . . . . . . . . . . . . . . . 25 89 12.2. Informative References . . . . . . . . . . . . . . . . . 27 90 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27 92 1. Introduction 94 Segment Routing (SR) allows a flexible definition of end-to-end paths 95 within IGP topologies by encoding paths as sequences of topological 96 sub-paths, called "segments". These segments are advertised by the 97 link-state routing protocols (IS-IS and OSPF). Prefix segments 98 represent an ECMP-aware shortest-path to a prefix (or a node), as per 99 the state of the IGP topology. Adjacency segments represent a hop 100 over a specific adjacency between two nodes in the IGP. A prefix 101 segment is typically a multi-hop path while an adjacency segment, in 102 most cases, is a one-hop path. SR's control-plane can be applied to 103 both IPv6 and MPLS data-planes, and does not require any additional 104 signalling (other than IGP extensions). The IPv6 data plane is out 105 of the scope of this specification - OSPFv3 extension for SR with 106 IPv6 data plane will be specified in a separate document. When used 107 in MPLS networks, SR paths do not require any LDP or RSVP-TE 108 signalling. However, SR can interoperate in the presence of LSPs 109 established with RSVP or LDP. 111 There are additional segment types, e.g., Binding SID defined in 112 [RFC8402]. 114 This draft describes the OSPFv3 extensions required for Segment 115 Routing with MPLS data plane. 117 Segment Routing architecture is described in [RFC8402]. 119 Segment Routing use cases are described in [RFC7855]. 121 2. Terminology 123 This section lists some of the terminology used in this document: 125 ABR - Area Border Router 127 Adj-SID - Adjacency Segment Identifier 129 AS - Autonomous System 131 ASBR - Autonomous System Boundary Router 133 IS-IS - Intermediate System to Intermediate System 135 LDP - Label Distribution Protocol 137 LSP - Label Switched Path 139 MPLS - Multi Protocol Label Switching 141 OSPF - Open Shortest Path First 143 SPF - Shortest Path First 144 RSVP - Resource Reservation Protocol 146 SID - Segment Identifier 148 SR - Segment Routing 150 SRGB - Segment Routing Global Block 152 SRLB - Segment Routing Local Block 154 SRMS - Segment Routing Mapping Server 156 TLV - Type Length Value 158 3. Segment Routing Identifiers 160 Segment Routing defines various types of Segment Identifiers (SIDs): 161 Prefix-SID, Adjacency-SID, LAN Adjacency SID, and Binding SID. 163 3.1. SID/Label Sub-TLV 165 The SID/Label Sub-TLV appears in multiple TLVs or Sub-TLVs defined 166 later in this document. It is used to advertise the SID or label 167 associated with a prefix or adjacency. The SID/Label Sub-TLV has 168 following format: 170 0 1 2 3 171 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 1 172 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 173 | Type | Length | 174 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 175 | SID/Label (variable) | 176 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 178 where: 180 Type: 7 182 Length: Variable, 3 or 4 octets 184 SID/Label: If length is set to 3, then the 20 rightmost bits 185 represent a label. If length is set to 4, then the value 186 represents a 32-bit SID. 188 The receiving router MUST ignore the SID/Label Sub-TLV if the 189 length is other than 3 or 4. 191 4. Segment Routing Capabilities 193 Segment Routing requires some additional router capabilities to be 194 advertised to other routers in the area. 196 These SR capabilities are advertised in the OSPFv3 Router Information 197 Opaque LSA (defined in [RFC7770]). 199 4.1. SR-Algorithm TLV 201 The SR-Algorithm TLV is a top-level TLV of the OSPFv3 Router 202 Information Opaque LSA (defined in [RFC7770]). 204 The SR-Algorithm TLV is optional. It SHOULD only be advertised once 205 in the OSPFv3 Router Information Opaque LSA. If the SR-Algorithm TLV 206 is not advertised by the node, such node is considered as not being 207 segment routing capable. 209 An SR router can use various algorithms when calculating reachability 210 to OSPFv3 routers or prefixes in an OSPFv3 area. Examples of these 211 algorithms are metric-based Shortest Path First (SPF), various 212 flavors of Constrained SPF, etc. The SR-Algorithm TLV allows a 213 router to advertise the algorithms currently used by the router to 214 other routers in an OSPFv3 area. The SR-Algorithm TLV has following 215 format: 217 0 1 2 3 218 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 1 219 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 220 | Type | Length | 221 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 222 | Algorithm 1 | Algorithm... | Algorithm n | | 223 +- -+ 224 | | 225 + + 227 where: 229 Type: 8 as defined in [I-D.ietf-ospf-segment-routing-extensions] 230 and applicable to OSPFv3. 232 Length: Variable, in octets, dependent on number of algorithms 233 advertised. 235 Algorithm: Single octet identifying the algorithm. Algorithms are 236 defined in "IGP Algorithm Type" registry under "Interior Gateway 237 Protocol (IGP) Parameters" [ALGOREG], defined in 238 [I-D.ietf-ospf-segment-routing-extensions]. 240 When multiple SR-Algorithm TLVs are received from a given router, the 241 receiver MUST use the first occurrence of the TLV in the OSPFv3 242 Router Information Opaque LSA. If the SR-Algorithm TLV appears in 243 multiple OSPFv3 Router Information Opaque LSAs that have different 244 flooding scopes, the SR-Algorithm TLV in the OSPFv3 Router 245 Information Opaque LSA with the area-scoped flooding scope MUST be 246 used. If the SR-Algorithm TLV appears in multiple OSPFv3 Router 247 Information Opaque LSAs that have the same flooding scope, the SR- 248 Algorithm TLV in the OSPFv3 Router Information Opaque LSA with the 249 numerically smallest Instance ID MUST be used and subsequent 250 instances of the SR-Algorithm TLV MUST be ignored. 252 The OSPFv3 Router Information Opaque LSA can be advertised at any of 253 the defined opaque flooding scopes (link, area, or Autonomous System 254 (AS)). For the purpose of SR-Algorithm TLV advertisement, area- 255 scoped flooding is REQUIRED. 257 4.2. SID/Label Range TLV 259 Prefix SIDs MAY be advertised in a form of an index as described in 260 Section 6. Such index defines the offset in the SID/Label space 261 advertised by the router. The SID/Label Range TLV is used to 262 advertise such SID/Label space. 264 The SID/Label Range TLV is a top-level TLV of the OSPFv3 Router 265 Information Opaque LSA (defined in [RFC7770]). 267 The SID/Label Range TLV MAY appear multiple times and has the 268 following format: 270 0 1 2 3 271 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 1 272 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 273 | Type | Length | 274 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 275 | Range Size | Reserved | 276 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 277 | Sub-TLVs (variable) | 278 +- -+ 279 | | 280 + + 282 where: 284 Type: 9 as defined in [I-D.ietf-ospf-segment-routing-extensions] 285 and applicable to OSPFv3. 287 Length: Variable, in octets, dependent on Sub-TLVs. 289 Range Size: 3-octet SID/label range size (i.e., the number of SIDs 290 or labels in the range including the first SID/label). It MUST be 291 greater than 0. 293 Reserved: SHOULD be set to 0 on transmission and MUST be ignored 294 on reception. 296 Initially, the only supported Sub-TLV is the SID/Label Sub-TLV as 297 defined in Section 3.1. The SID/Label Sub-TLV MUST be included in 298 the SID/Label Range TLV. The SID/Label advertised in the SID/Label 299 Sub-TLV represents the first SID/Label in the advertised range. 301 Only a single SID/Label Sub-TLV MAY be advertised in SID/Label Range 302 TLV. If more than one SID/Label Sub-TLVs are present, the SID/Label 303 Range TLV MUST be ignored. 305 Multiple occurrences of the SID/Label Range TLV MAY be advertised, in 306 order to advertise multiple ranges. In such case: 308 o The originating router MUST encode each range into a different 309 SID/Label Range TLV. 311 o The originating router decides the order in which the set of SID/ 312 Label Range TLVs are advertised inside the Router Information 313 Opaque LSA. The originating router MUST ensure the order is the 314 same after a graceful restart (using checkpointing, non-volatile 315 storage, or any other mechanism) in order to assure the SID/label 316 range and SID index correspondence is preserved across graceful 317 restarts. 319 o The receiving router MUST adhere to the order in which the ranges 320 are advertised when calculating a SID/label from a SID index. 322 o The originating router MUST NOT advertise overlapping ranges. 324 o When a router receives multiple overlapping ranges, it MUST 325 conform to the procedures defined in section 2.3 of 326 [I-D.ietf-spring-segment-routing-mpls]. 328 The following example illustrates the advertisement of multiple 329 ranges: 331 The originating router advertises the following ranges: 333 Range 1: Range Size: 100 SID/Label Sub-TLV: 100 334 Range 1: Range Size: 100 SID/Label Sub-TLV: 1000 335 Range 1: Range Size: 100 SID/Label Sub-TLV: 500 337 The receiving routers concatenate the ranges and build the Segment 338 Routing Global Block (SRGB) as follows: 340 SRGB = [100, 199] 341 [1000, 1099] 342 [500, 599] 344 The indexes span multiple ranges: 346 index=0 means label 100 347 ... 348 index 99 means label 199 349 index 100 means label 1000 350 index 199 means label 1099 351 ... 352 index 200 means label 500 353 ... 355 The OSPFv3 Router Information Opaque LSA can be advertised at any of 356 the defined flooding scopes (link, area, or autonomous system (AS)). 357 For the purpose of SID/Label Range TLV advertisement, area-scoped 358 flooding is REQUIRED. 360 4.3. SR Local Block TLV 362 The SR Local Block TLV (SRLB TLV) contains the range of labels the 363 node has reserved for local SIDs. SIDs from the SRLB MAY be used for 364 Adjacency-SIDs, but also by components other than the OSPFv3 365 protocol. As an example, an application or a controller can instruct 366 the router to allocate a specific local SID. Some controllers or 367 applications can use the control plane to discover the available set 368 of local SIDs on a particular router. In such cases, the SRLB is 369 advertised in the control plane. The requirement to advertise the 370 SRLB is further described in [I-D.ietf-spring-segment-routing-mpls]. 371 The SRLB TLV is used to advertise the SRLB. 373 The SRLB TLV is a top-level TLV of the OSPFv3 Router Information 374 Opaque LSA (defined in [RFC7770]). 376 The SRLB TLV MAY appear multiple times in the OSPFv3 Router 377 Information Opaque LSA and has the following format: 379 0 1 2 3 380 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 1 381 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 382 | Type | Length | 383 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 384 | Range Size | Reserved | 385 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 386 | Sub-TLVs (variable) | 387 +- -+ 388 | | 389 + + 391 where: 393 Type: 14 as defined in [I-D.ietf-ospf-segment-routing-extensions] 394 and applicable to OSPFv3. 396 Length: Variable, in octets, dependent on Sub-TLVs. 398 Range Size: 3-octet SID/label range size (i.e., the number of SIDs 399 or labels in the range including the first SID/label). It MUST be 400 greater than 0. 402 Reserved: SHOULD be set to 0 on transmission and MUST be ignored 403 on reception. 405 Initially, the only supported Sub-TLV is the SID/Label Sub-TLV as 406 defined in Section 3.1. The SID/Label Sub-TLV MUST be included in 407 the SRLB TLV. The SID/Label advertised in the SID/Label Sub-TLV 408 represents the first SID/Label in the advertised range. 410 Only a single SID/Label Sub-TLV MAY be advertised in the SRLB TLV. 411 If more than one SID/Label Sub-TLVs are present, the SRLB TLV MUST be 412 ignored. 414 The originating router MUST NOT advertise overlapping ranges. 416 When a router receives multiple overlapping ranges, it MUST conform 417 to the procedures defined in section 2.3 of 418 [I-D.ietf-spring-segment-routing-mpls]. 420 Each time a SID from the SRLB is allocated, it SHOULD also be 421 reported to all components (e.g., controller or applications) in 422 order for these components to have an up-to-date view of the current 423 SRLB allocation. This is required to avoid collisions between 424 allocation instructions. 426 Within the context of OSPFv3, the reporting of local SIDs is done 427 through OSPFv3 Sub-TLVs such as the Adjacency-SID (Section 7). 428 However, the reporting of allocated local SIDs can also be done 429 through other means and protocols which are outside the scope of this 430 document. 432 A router advertising the SRLB TLV MAY also have other label ranges, 433 outside of the SRLB, used for its local allocation purposes which are 434 not advertised in the SRLB TLV. For example, it is possible that an 435 Adjacency-SID is allocated using a local label that is not part of 436 the SRLB. 438 The OSPFv3 Router Information Opaque LSA can be advertised at any of 439 the defined flooding scopes (link, area, or autonomous system (AS)). 440 For the purpose of SRLB TLV advertisement, area-scoped flooding is 441 REQUIRED. 443 4.4. SRMS Preference TLV 445 The Segment Routing Mapping Server Preference TLV (SRMS Preference 446 TLV) is used to advertise a preference associated with a node that 447 acts as an SR Mapping Server. The role of an SRMS is described in 448 [I-D.ietf-spring-segment-routing-ldp-interop]. SRMS preference is 449 defined in [I-D.ietf-spring-segment-routing-ldp-interop]. 451 The SRMS Preference TLV is a top-level TLV of the OSPFv3 Router 452 Information Opaque LSA (defined in [RFC7770]). 454 The SRMS Preference TLV MAY only be advertised once in the OSPFv3 455 Router Information Opaque LSA and has the following format: 457 0 1 2 3 458 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 1 459 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 460 | Type | Length | 461 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 462 | Preference | Reserved | 463 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 465 where: 467 Type: 15 as defined in [I-D.ietf-ospf-segment-routing-extensions] 468 and applicable to OSPFv3. 470 Length: 4 octets 472 Preference: 1 octet. SRMS preference value from 0 to 255. 474 Reserved: SHOULD be set to 0 on transmission and MUST be ignored 475 on reception. 477 When multiple SRMS Preference TLVs are received from a given router, 478 the receiver MUST use the first occurrence of the TLV in the OSPFv3 479 Router Information Opaque LSA. If the SRMS Preference TLV appears in 480 multiple OSPFv3 Router Information Opaque LSAs that have different 481 flooding scopes, the SRMS Preference TLV in the OSPFv3 Router 482 Information Opaque LSA with the narrowest flooding scope MUST be 483 used. If the SRMS Preference TLV appears in multiple OSPFv3 Router 484 Information Opaque LSAs that have the same flooding scope, the SRMS 485 Preference TLV in the OSPFv3 Router Information Opaque LSA with the 486 numerically smallest Instance ID MUST be used and subsequent 487 instances of the SRMS Preference TLV MUST be ignored. 489 The OSPFv3 Router Information Opaque LSA can be advertised at any of 490 the defined flooding scopes (link, area, or autonomous system (AS)). 491 For the purpose of the SRMS Preference TLV advertisement, AS-scoped 492 flooding SHOULD be used. This is because SRMS servers can be located 493 in different areas than consumers of the SRMS advertisements. If 494 SRMS advertisements from an SRMS server are only used inside the SRMS 495 server's area, area-scoped flooding MAY be used. 497 5. OSPFv3 Extended Prefix Range TLV 499 In some cases it is useful to advertise attributes for a range of 500 prefixes. The Segment Routing Mapping Server, which is described in 501 [I-D.ietf-spring-segment-routing-ldp-interop], is an example of where 502 we need a single advertisement to advertise SIDs for multiple 503 prefixes from a contiguous address range. 505 The OSPFv3 Extended Prefix Range TLV is defined for this purpose. 507 The OSPFv3 Extended Prefix Range TLV is a top-level TLV of the 508 following LSAs defined in [RFC8362]: 510 E-Intra-Area-Prefix-LSA 512 E-Inter-Area-Prefix-LSA 514 E-AS-External-LSA 516 E-Type-7-LSA 518 Multiple OSPFv3 Extended Prefix Range TLVs MAY be advertised in each 519 LSA mentioned above. The OSPFv3 Extended Prefix Range TLV has the 520 following format: 522 0 1 2 3 523 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 1 524 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 525 | Type | Length | 526 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 527 | Prefix Length | AF | Range Size | 528 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 529 | Flags | Reserved | 530 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 531 | Address Prefix (variable) | 532 | ... | 533 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 534 | Sub-TLVs (variable) | 535 +- -+ 536 | | 538 where: 540 Type: 9 542 Length: Variable, in octets, dependent on Sub-TLVs. 544 Prefix length: Length of prefix in bits. 546 AF: Address family for the prefix. 548 AF: 0 - IPv4 unicast 550 AF: 1 - IPv6 unicast 552 Range size: Represents the number of prefixes that are covered by 553 the advertisement. The Range Size MUST NOT exceed the number of 554 prefixes that could be satisfied by the prefix length without 555 including: 557 Addresses from the IPv4 multicast address range (224.0.0.0/3), 558 if the AF is IPv4 unicast 560 Addresses other than the IPv6 unicast addresses, if the AF is 561 IPv6 unicast 563 Flags: Single octet field. The following flags are defined: 565 0 1 2 3 4 5 6 7 566 +--+--+--+--+--+--+--+--+ 567 |IA| | | | | | | | 568 +--+--+--+--+--+--+--+--+ 570 where: 572 IA-Flag: Inter-Area flag. If set, advertisement is of inter- 573 area type. An Are Border Router (ABR) that is advertising the 574 OSPFv3 Extended Prefix Range TLV between areas MUST set this 575 bit. 577 This bit is used to prevent redundant flooding of Prefix Range 578 TLVs between areas as follows: 580 An ABR only propagates an inter-area Prefix Range 581 advertisement from the backbone area to connected non- 582 backbone areas if the advertisement is considered to be the 583 best one. The following rules are used to select the best 584 range from the set of advertisements for the same Prefix 585 Range: 587 An ABR always prefers intra-area Prefix Range 588 advertisements over inter-area advertisements. 590 An ABR does not consider inter-area Prefix Range 591 advertisements coming from non-backbone areas. 593 Other bits: Reserved. These MUST be zero when sent and are 594 ignored when received. 596 Reserved: SHOULD be set to 0 on transmission and MUST be ignored 597 on reception. 599 Address Prefix: 601 For the address family IPv4 unicast, the prefix itself is 602 encoded as a 32-bit value. The default route is represented by 603 a prefix of length 0. 605 For the address family IPv6 unicast, the prefix, encoded as an 606 even multiple of 32-bit words, padded with zeroed bits as 607 necessary. This encoding consumes ((PrefixLength + 31) / 32) 608 32-bit words. 610 Prefix encoding for other address families is beyond the scope 611 of this specification. 613 If the OSPFv3 Extended Prefix Range TLVs advertising the exact same 614 range appears in multiple LSAs of the same type, originated by the 615 same OSPFv3 router, the LSA with the numerically smallest Instance ID 616 MUST be used and subsequent instances of the OSPFv3 Extended Prefix 617 Range TLVs MUST be ignored. 619 6. Prefix SID Sub-TLV 621 The Prefix SID Sub-TLV is a Sub-TLV of the following OSPFv3 TLVs as 622 defined in [RFC8362] and in Section 5: 624 Intra-Area Prefix TLV 626 Inter-Area Prefix TLV 628 External Prefix TLV 630 OSPFv3 Extended Prefix Range TLV 632 It MAY appear more than once in the parent TLV and has the following 633 format: 635 0 1 2 3 636 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 1 637 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 638 | Type | Length | 639 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 640 | Flags | Algorithm | Reserved | 641 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 642 | SID/Index/Label (variable) | 643 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 644 where: 646 Type: 4 648 Length: 7 or 8 octets, dependent on the V-flag 650 Flags: Single octet field. The following flags are defined: 652 0 1 2 3 4 5 6 7 653 +--+--+--+--+--+--+--+--+ 654 | |NP|M |E |V |L | | | 655 +--+--+--+--+--+--+--+--+ 656 where: 658 NP-Flag: No-PHP flag. If set, then the penultimate hop MUST 659 NOT pop the Prefix-SID before delivering packets to the node 660 that advertised the Prefix-SID. 662 M-Flag: Mapping Server Flag. If set, the SID was advertised by 663 a Segment Routing Mapping Server as described in 664 [I-D.ietf-spring-segment-routing-ldp-interop]. 666 E-Flag: Explicit-Null Flag. If set, any upstream neighbor of 667 the Prefix-SID originator MUST replace the Prefix-SID with the 668 Explicit-NULL label (0 for IPv4, 2 for IPv6) before forwarding 669 the packet. 671 V-Flag: Value/Index Flag. If set, then the Prefix-SID carries 672 an absolute value. If not set, then the Prefix-SID carries an 673 index. 675 L-Flag: Local/Global Flag. If set, then the value/index 676 carried by the Prefix-SID has local significance. If not set, 677 then the value/index carried by this Sub-TLV has global 678 significance. 680 Other bits: Reserved. These MUST be zero when sent and are 681 ignored when received. 683 Reserved: SHOULD be set to 0 on transmission and MUST be ignored 684 on reception. 686 Algorithm: Single octet identifying the algorithm the Prefix-SID 687 is associated with as defined in Section 4.1. 689 A router receiving a Prefix-SID from a remote node and with an 690 algorithm value that such remote node has not advertised in the 691 SR-Algorithm Sub-TLV (Section 4.1) MUST ignore the Prefix-SID Sub- 692 TLV. 694 SID/Index/Label: According to the V and L flags, it contains 695 either: 697 A 32-bit index defining the offset in the SID/Label space 698 advertised by this router. 700 A 24-bit label where the 20 rightmost bits are used for 701 encoding the label value. 703 If an OSPFv3 router advertises multiple Prefix-SIDs for the same 704 prefix, topology, and algorithm, all of them MUST be ignored. 706 When calculating the outgoing label for the prefix, the router MUST 707 take into account, as described below, the E, NP, and M flags 708 advertised by the next-hop router if that router advertised the SID 709 for the prefix. This MUST be done regardless of whether the next-hop 710 router contributes to the best path to the prefix. 712 The NP-Flag (No-PHP) MUST be set and the E-flag MUST be clear for 713 Prefix-SIDs allocated to prefixes that are propagated between areas 714 by an ABR based on intra-area or inter-area reachability, unless the 715 advertised prefix is directly attached to such ABR. 717 The NP-Flag (No-PHP) MUST be set and the E-flag MUST be clear for 718 Prefix-SIDs allocated to redistributed prefixes, unless the 719 redistributed prefix is directly attached to the advertising 720 Autonomous System Boundary Router (ASBR). 722 If the NP-Flag is not set, then any upstream neighbor of the Prefix- 723 SID originator MUST pop the Prefix-SID. This is equivalent to the 724 penultimate hop popping mechanism used in the MPLS dataplane. If the 725 NP-flag is not set, then the received E-flag is ignored. 727 If the NP-flag is set then: 729 If the E-flag is not set, then any upstream neighbor of the 730 Prefix-SID originator MUST keep the Prefix-SID on top of the 731 stack. This is useful when the originator of the Prefix-SID needs 732 to stitch the incoming packet into a continuing MPLS LSP to the 733 final destination. This could occur at an Area Border Router 734 (prefix propagation from one area to another) or at an AS Boundary 735 Router (prefix propagation from one domain to another). 737 If the E-flag is set, then any upstream neighbor of the Prefix-SID 738 originator MUST replace the Prefix-SID with an Explicit-NULL 739 label. This is useful, e.g., when the originator of the Prefix- 740 SID is the final destination for the related prefix and the 741 originator wishes to receive the packet with the original EXP 742 bits. 744 When the M-Flag is set, the NP-flag and the E-flag MUST be ignored on 745 reception. 747 As the Mapping Server does not specify the originator of a prefix 748 advertisement, it is not possible to determine PHP behavior solely 749 based on the Mapping Server advertisement. However, PHP behavior 750 SHOULD be done in following cases: 752 The Prefix is intra-area type and the downstream neighbor is the 753 originator of the prefix. 755 The Prefix is inter-area type and the downstream neighbor is an 756 ABR, which is advertising prefix reachability and is setting the 757 LA-bit in the Prefix Options as described in [RFC8362]. 759 The Prefix is external type and the downstream neighbor is an 760 ASBR, which is advertising prefix reachability and is setting the 761 LA-bit in the Prefix Options as described in [RFC8362]. 763 When a Prefix-SID is advertised in the OSPFv3 Extended Prefix Range 764 TLV, then the value advertised in the Prefix SID Sub-TLV is 765 interpreted as a starting SID/Label value. 767 Example 1: If the following router addresses (loopback addresses) 768 need to be mapped into the corresponding Prefix SID indexes: 770 Router-A: 2001:DB8::1/128, Prefix-SID: Index 1 771 Router-B: 2001:DB8::2/128, Prefix-SID: Index 2 772 Router-C: 2001:DB8::3/128, Prefix-SID: Index 3 773 Router-D: 2001:DB8::4/128, Prefix-SID: Index 4 775 then the Address Prefix field in the OSPFv3 Extended Prefix Range TLV 776 would be set to 2001:DB8::1, the Prefix Length would be set to 128, 777 the Range Size would be set to 4, and the Index value in the Prefix- 778 SID Sub-TLV would be set to 1. 780 Example 2: If the following prefixes need to be mapped into the 781 corresponding Prefix-SID indexes: 783 2001:DB8:1::0/120, Prefix-SID: Index 51 784 2001:DB8:1::100/120, Prefix-SID: Index 52 785 2001:DB8:1::200/120, Prefix-SID: Index 53 786 2001:DB8:1::300/120, Prefix-SID: Index 54 787 2001:DB8:1::400/120, Prefix-SID: Index 55 788 2001:DB8:1::500/120, Prefix-SID: Index 56 789 2001:DB8:1::600/120, Prefix-SID: Index 57 791 then the Prefix field in the OSPFv3 Extended Prefix Range TLV would 792 be set to 2001:DB8:1::0, the Prefix Length would be set to 120, the 793 Range Size would be set to 7, and the Index value in the Prefix-SID 794 Sub-TLV would be set to 51. 796 7. Adjacency Segment Identifier (Adj-SID) 798 An Adjacency Segment Identifier (Adj-SID) represents a router 799 adjacency in Segment Routing. 801 7.1. Adj-SID Sub-TLV 803 The Adj-SID Sub-TLV is an optional Sub-TLV of the Router-Link TLV as 804 defined in [RFC8362]. It MAY appear multiple times in the Router- 805 Link TLV. The Adj-SID Sub-TLV has the following format: 807 0 1 2 3 808 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 1 809 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 810 | Type | Length | 811 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 812 | Flags | Weight | Reserved | 813 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 814 | SID/Label/Index (variable) | 815 +---------------------------------------------------------------+ 817 where: 819 Type: 5 821 Length: 7 or 8 octets, dependent on the V flag. 823 Flags: Single octet field containing the following flags: 825 0 1 2 3 4 5 6 7 826 +-+-+-+-+-+-+-+-+ 827 |B|V|L|G|P| | 828 +-+-+-+-+-+-+-+-+ 830 where: 832 B-Flag: Backup Flag. If set, the Adj-SID refers to an 833 adjacency that is eligible for protection (e.g., using IPFRR or 834 MPLS-FRR) as described in section 3.5 of [RFC8402]. 836 The V-Flag: Value/Index Flag. If set, then the Adj-SID carries 837 an absolute value. If not set, then the Adj-SID carries an 838 index. 840 The L-Flag: Local/Global Flag. If set, then the value/index 841 carried by the Adj-SID has local significance. If not set, 842 then the value/index carried by this Sub-TLV has global 843 significance. 845 The G-Flag: Group Flag. When set, the G-Flag indicates that 846 the Adj-SID refers to a group of adjacencies (and therefore MAY 847 be assigned to other adjacencies as well). 849 P-Flag. Persistent flag. When set, the P-Flag indicates that 850 the Adj-SID is persistently allocated, i.e., the Adj-SID value 851 remains the same across router restart and/or interface flap. 853 Other bits: Reserved. These MUST be zero when sent and are 854 ignored when received. 856 Reserved: SHOULD be set to 0 on transmission and MUST be ignored 857 on reception. 859 Weight: Weight used for load-balancing purposes. The use of the 860 weight is defined in [RFC8402]. 862 SID/Index/Label: According to the V and L flags, it contains 863 either: 865 A 32-bit index defining the offset in the SID/Label space 866 advertised by this router. 868 A 24-bit label where the 20 rightmost bits are used for 869 encoding the label value. 871 An SR-capable router MAY allocate an Adj-SID for each of its 872 adjacencies and set the B-Flag when the adjacency is eligible for 873 protection by an FRR mechanism (IP or MPLS) as described in 874 [RFC8402]. 876 An SR-capable router MAY allocate more than one Adj-SID to an 877 adjacency. 879 An SR-capable router MAY allocate the same Adj-SID to different 880 adjacencies. 882 When the P-flag is not set, the Adj-SID MAY be persistent. When the 883 P-flag is set, the Adj-SID MUST be persistent. 885 7.2. LAN Adj-SID Sub-TLV 887 The LAN Adj-SID Sub-TLV is an optional Sub-TLV of the Router-Link 888 TLV. It MAY appear multiple times in the Router-Link TLV. It is 889 used to advertise a SID/Label for an adjacency to a non-DR router on 890 a broadcast, NBMA, or hybrid [RFC6845] network. 892 0 1 2 3 893 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 1 894 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 895 | Type | Length | 896 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 897 | Flags | Weight | Reserved | 898 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 899 | Neighbor ID | 900 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 901 | SID/Label/Index (variable) | 902 +---------------------------------------------------------------+ 904 where: 906 Type: 6 908 Length: 11 or 12 octets, dependent on V-flag. 910 Flags: same as in Section 7.1 912 Weight: Weight used for load-balancing purposes. The use of the 913 weight is defined in [RFC8402]. 915 Reserved: SHOULD be set to 0 on transmission and MUST be ignored 916 on reception. 918 Neighbor ID: The Router ID of the neighbor for which the LAN-Adj- 919 SID is advertised. 921 SID/Index/Label: According to the V and L flags, it contains 922 either: 924 A 32-bit index defining the offset in the SID/Label space 925 advertised by this router. 927 A 24-bit label where the 20 rightmost bits are used for 928 encoding the label value. 930 When the P-flag is not set, the Adj-SID MAY be persistent. When 931 the P-flag is set, the Adj-SID MUST be persistent. 933 8. Elements of Procedure 935 8.1. Intra-area Segment routing in OSPFv3 937 An OSPFv3 router that supports segment routing MAY advertise Prefix- 938 SIDs for any prefix to which it is advertising reachability (e.g., a 939 loopback IP address as described in Section 6). 941 A Prefix-SID can also be advertised by SR Mapping Servers (as 942 described in [I-D.ietf-spring-segment-routing-ldp-interop]). A 943 Mapping Server advertises Prefix-SIDs for remote prefixes that exist 944 in the OSPFv3 routing domain. Multiple Mapping Servers can advertise 945 Prefix-SIDs for the same prefix, in which case the same Prefix-SID 946 MUST be advertised by all of them. The SR Mapping Server could use 947 either area flooding scope or autonomous system flooding scope when 948 advertising Prefix SIDs for prefixes, based on the configuration of 949 the SR Mapping Server. Depending on the flooding scope used, the SR 950 Mapping Server chooses the OSPFv3 LSA type that will be used. If the 951 area flooding scope is needed, an E-Intra-Area-Prefix-LSA [RFC8362] 952 is used. If autonomous system flooding scope is needed, an E-AS- 953 External-LSA [RFC8362] is used. 955 When a Prefix-SID is advertised by the Mapping Server, which is 956 indicated by the M-flag in the Prefix-SID Sub-TLV (Section 6), the 957 route type as implied by the LSA type is ignored and the Prefix-SID 958 is bound to the corresponding prefix independent of the route type. 960 Advertisement of the Prefix-SID by the Mapping Server using an Inter- 961 Area Prefix TLV, External-Prefix TLV, or Intra-Area-Prefix TLV 962 [RFC8362] does not itself contribute to the prefix reachability. The 963 NU-bit MUST be set in the PrefixOptions field of the LSA which is 964 used by the Mapping Server to advertise SID or SID Range, which 965 prevents the advertisement from contributing to prefix reachability. 967 An SR Mapping Server MUST use the OSPFv3 Extended Prefix Range TLVs 968 when advertising SIDs for prefixes. Prefixes of different route- 969 types can be combined in a single OSPFv3 Extended Prefix Range TLV 970 advertised by an SR Mapping Server. 972 Area-scoped OSPFv3 Extended Prefix Range TLVs are propagated between 973 areas. Similar to propagation of prefixes between areas, an ABR only 974 propagates the OSPFv3 Extended Prefix Range TLV that it considers to 975 be the best from the set it received. The rules used to pick the 976 best OSPFv3 Extended Prefix Range TLV are described in Section 5. 978 When propagating an OSPFv3 Extended Prefix Range TLV between areas, 979 ABRs MUST set the IA-Flag, that is used to prevent redundant flooding 980 of the OSPFv3 Extended Prefix Range TLV between areas as described in 981 Section 5. 983 8.2. Inter-area Segment routing in OSPFv3 985 In order to support SR in a multi-area environment, OSPFv3 MUST 986 propagate Prefix-SID information between areas. The following 987 procedure is used to propagate Prefix SIDs between areas. 989 When an OSPFv3 ABR advertises an Inter-Area-Prefix-LSA from an intra- 990 area prefix to all its connected areas, it will also include the 991 Prefix-SID Sub-TLV, as described in Section 6. The Prefix-SID value 992 will be set as follows: 994 The ABR will look at its best path to the prefix in the source 995 area and find the advertising router associated with the best path 996 to that prefix. 998 The ABR will then determine if such router advertised a Prefix-SID 999 for the prefix and use it when advertising the Prefix-SID to other 1000 connected areas. 1002 If no Prefix-SID was advertised for the prefix in the source area 1003 by the router that contributes to the best path to the prefix, the 1004 originating ABR will use the Prefix-SID advertised by any other 1005 router when propagating the Prefix-SID for the prefix to other 1006 areas. 1008 When an OSPFv3 ABR advertises Inter-Area-Prefix-LSA LSAs from an 1009 inter-area route to all its connected areas, it will also include the 1010 Prefix-SID Sub-TLV, as described in Section 6. The Prefix-SID value 1011 will be set as follows: 1013 The ABR will look at its best path to the prefix in the backbone 1014 area and find the advertising router associated with the best path 1015 to that prefix. 1017 The ABR will then determine if such router advertised a Prefix-SID 1018 for the prefix and use it when advertising the Prefix-SID to other 1019 connected areas. 1021 If no Prefix-SID was advertised for the prefix in the backbone 1022 area by the ABR that contributes to the best path to the prefix, 1023 the originating ABR will use the Prefix-SID advertised by any 1024 other router when propagating the Prefix-SID for the prefix to 1025 other areas. 1027 8.3. Segment Routing for External Prefixes 1029 AS-External-LSAs are flooded domain wide. When an ASBR, which 1030 supports SR, originates an E-AS-External-LSA, it SHOULD also include 1031 a Prefix-SID Sub-TLV, as described in Section 6. The Prefix-SID 1032 value will be set to the SID that has been reserved for that prefix. 1034 When an NSSA [RFC3101] ABR translates an E-NSSA-LSA into an E-AS- 1035 External-LSA, it SHOULD also advertise the Prefix-SID for the prefix. 1036 The NSSA ABR determines its best path to the prefix advertised in the 1037 translated E-NSSA-LSA and finds the advertising router associated 1038 with that path. If the advertising router has advertised a Prefix- 1039 SID for the prefix, then the NSSA ABR uses it when advertising the 1040 Prefix-SID for the E-AS-External-LSA. Otherwise, the Prefix-SID 1041 advertised by any other router will be used. 1043 8.4. Advertisement of Adj-SID 1045 The Adjacency Segment Routing Identifier (Adj-SID) is advertised 1046 using the Adj-SID Sub-TLV as described in Section 7. 1048 8.4.1. Advertisement of Adj-SID on Point-to-Point Links 1050 An Adj-SID MAY be advertised for any adjacency on a P2P link that is 1051 in neighbor state 2-Way or higher. If the adjacency on a P2P link 1052 transitions from the FULL state, then the Adj-SID for that adjacency 1053 MAY be removed from the area. If the adjacency transitions to a 1054 state lower than 2-Way, then the Adj-SID advertisement MUST be 1055 withdrawn from the area. 1057 8.4.2. Adjacency SID on Broadcast or NBMA Interfaces 1059 Broadcast, NBMA, or hybrid [RFC6845] networks in OSPFv3 are 1060 represented by a star topology where the Designated Router (DR) is 1061 the central point to which all other routers on the broadcast, NBMA, 1062 or hybrid network connect. As a result, routers on the broadcast, 1063 NBMA, or hybrid network advertise only their adjacency to the DR. 1064 Routers that do not act as DR do not form or advertise adjacencies 1065 with each other. They do, however, maintain 2-Way adjacency state 1066 with each other and are directly reachable. 1068 When Segment Routing is used, each router on the broadcast, NBMA, or 1069 hybrid network MAY advertise the Adj-SID for its adjacency to the DR 1070 using the Adj-SID Sub-TLV as described in Section 7.1. 1072 SR-capable routers MAY also advertise a LAN-Adj-SID for other 1073 neighbors (e.g., BDR, DR-OTHER) on the broadcast, NBMA, or hybrid 1074 network using the LAN-Adj-SID Sub-TLV as described in Section 7.2. 1076 9. IANA Considerations 1078 This specification updates several existing OSPFv3 registries. 1080 9.1. OSPFv3 Extended-LSA TLV Registry 1082 Following values are allocated: 1084 o 9 - OSPFv3 Extended Prefix Range TLV 1086 9.2. OSPFv3 Extended-LSA Sub-TLV registry 1088 o 4 - Prefix SID Sub-TLV 1090 o 5 - Adj-SID Sub-TLV 1092 o 6 - LAN Adj-SID Sub-TLV 1094 o 7 - SID/Label Sub-TLV 1096 10. Security Considerations 1098 With the OSPFv3 segment routing extensions defined herein, OSPFv3 1099 will now program the MPLS data plane [RFC3031]. Previously, LDP 1100 [RFC5036] or another label distribution mechanism was required to 1101 advertise MPLS labels and program the MPLS data plane. 1103 In general, the same types of attacks that can be carried out on the 1104 IP control plane can be carried out on the MPLS control plane 1105 resulting in traffic being misrouted in the respective data planes. 1106 However, the latter can be more difficult to detect and isolate. 1108 Existing security extensions as described in [RFC5340] and [RFC8362] 1109 apply to these segment routing extensions. While OSPFv3 is under a 1110 single administrative domain, there can be deployments where 1111 potential attackers have access to one or more networks in the OSPFv3 1112 routing domain. In these deployments, stronger authentication 1113 mechanisms such as those specified in [RFC4552] or [RFC7166] SHOULD 1114 be used. 1116 Implementations MUST assure that malformed TLV and Sub-TLV defined in 1117 this document are detected and do not provide a vulnerability for 1118 attackers to crash the OSPFv3 router or routing process. Reception 1119 of a malformed TLV or Sub-TLV SHOULD be counted and/or logged for 1120 further analysis. Logging of malformed TLVs and Sub-TLVs SHOULD be 1121 rate-limited to prevent a Denial of Service (DoS) attack (distributed 1122 or otherwise) from overloading the OSPFv3 control plane. 1124 11. Contributors 1126 The following people gave a substantial contribution to the content 1127 of this document and should be considered as co-authors: 1129 Clarence Filsfils 1130 Cisco Systems, Inc. 1131 Brussels 1132 Belgium 1134 Email: cfilsfil@cisco.com 1136 Hannes Gredler 1137 RtBrick Inc. 1138 Austria 1140 Email: hannes@rtbrick.com 1142 Rob Shakir 1143 Google, Inc. 1144 1600 Amphitheatre Parkway 1145 Mountain View, CA 94043 1146 US 1148 Email: robjs@google.com 1150 Wim Henderickx 1151 Nokia 1152 Copernicuslaan 50 1153 Antwerp 2018 1154 BE 1156 Email: wim.henderickx@nokia.com 1158 Jeff Tantsura 1159 Nuage Networks 1160 US 1162 Email: jefftant.ietf@gmail.com 1164 Thanks to Acee Lindem for his substantial contribution to the content 1165 of this document. 1167 We would like to thank Anton Smirnov for his contribution as well. 1169 12. References 1171 12.1. Normative References 1173 [ALGOREG] "IGP Algorithm Types", . 1176 [I-D.ietf-ospf-segment-routing-extensions] 1177 Psenak, P., Previdi, S., Filsfils, C., Gredler, H., 1178 Shakir, R., Henderickx, W., and J. Tantsura, "OSPF 1179 Extensions for Segment Routing", draft-ietf-ospf-segment- 1180 routing-extensions-25 (work in progress), April 2018. 1182 [I-D.ietf-spring-segment-routing-ldp-interop] 1183 Bashandy, A., Filsfils, C., Previdi, S., Decraene, B., and 1184 S. Litkowski, "Segment Routing interworking with LDP", 1185 draft-ietf-spring-segment-routing-ldp-interop-15 (work in 1186 progress), September 2018. 1188 [I-D.ietf-spring-segment-routing-mpls] 1189 Bashandy, A., Filsfils, C., Previdi, S., Decraene, B., 1190 Litkowski, S., and R. Shakir, "Segment Routing with MPLS 1191 data plane", draft-ietf-spring-segment-routing-mpls-15 1192 (work in progress), October 2018. 1194 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1195 Requirement Levels", BCP 14, RFC 2119, 1196 DOI 10.17487/RFC2119, March 1997, 1197 . 1199 [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol 1200 Label Switching Architecture", RFC 3031, 1201 DOI 10.17487/RFC3031, January 2001, 1202 . 1204 [RFC3101] Murphy, P., "The OSPF Not-So-Stubby Area (NSSA) Option", 1205 RFC 3101, DOI 10.17487/RFC3101, January 2003, 1206 . 1208 [RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed., 1209 "LDP Specification", RFC 5036, DOI 10.17487/RFC5036, 1210 October 2007, . 1212 [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF 1213 for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, 1214 . 1216 [RFC6845] Sheth, N., Wang, L., and J. Zhang, "OSPF Hybrid Broadcast 1217 and Point-to-Multipoint Interface Type", RFC 6845, 1218 DOI 10.17487/RFC6845, January 2013, 1219 . 1221 [RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and 1222 S. Shaffer, "Extensions to OSPF for Advertising Optional 1223 Router Capabilities", RFC 7770, DOI 10.17487/RFC7770, 1224 February 2016, . 1226 [RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and 1227 F. Baker, "OSPFv3 Link State Advertisement (LSA) 1228 Extensibility", RFC 8362, DOI 10.17487/RFC8362, April 1229 2018, . 1231 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 1232 Decraene, B., Litkowski, S., and R. Shakir, "Segment 1233 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 1234 July 2018, . 1236 12.2. Informative References 1238 [RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality 1239 for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006, 1240 . 1242 [RFC7166] Bhatia, M., Manral, V., and A. Lindem, "Supporting 1243 Authentication Trailer for OSPFv3", RFC 7166, 1244 DOI 10.17487/RFC7166, March 2014, 1245 . 1247 [RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B., 1248 Litkowski, S., Horneffer, M., and R. Shakir, "Source 1249 Packet Routing in Networking (SPRING) Problem Statement 1250 and Requirements", RFC 7855, DOI 10.17487/RFC7855, May 1251 2016, . 1253 Authors' Addresses 1255 Peter Psenak (editor) 1256 Cisco Systems, Inc. 1257 Eurovea Centre, Central 3 1258 Pribinova Street 10 1259 Bratislava 81109 1260 Slovakia 1262 Email: ppsenak@cisco.com 1264 Stefano Previdi (editor) 1265 Individual 1267 Email: stefano.previdi@net