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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: draft-ietf-idr-bgpls-segment-routing-epe has been published as RFC 9086 == Outdated reference: A later version (-22) exists of draft-ietf-spring-segment-routing-policy-03 Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group S. Previdi 3 Internet-Draft 4 Intended status: Standards Track K. Talaulikar, Ed. 5 Expires: April 16, 2020 Cisco Systems, Inc. 6 J. Dong, Ed. 7 M. Chen 8 Huawei Technologies 9 H. Gredler 10 RtBrick Inc. 11 J. Tantsura 12 Apstra 13 October 14, 2019 15 Distribution of Traffic Engineering (TE) Policies and State using BGP-LS 16 draft-ietf-idr-te-lsp-distribution-12 18 Abstract 20 This document describes a mechanism to collect the Traffic 21 Engineering and Policy information that is locally available in a 22 node and advertise it into BGP Link State (BGP-LS) updates. Such 23 information can be used by external components for path computation, 24 re-optimization, service placement, network visualization, etc. 26 Requirements Language 28 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 29 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 30 "OPTIONAL" in this document are to be interpreted as described in BCP 31 14 [RFC2119] [RFC8174] when, and only when, they appear in all 32 capitals, as shown here. 34 Status of This Memo 36 This Internet-Draft is submitted in full conformance with the 37 provisions of BCP 78 and BCP 79. 39 Internet-Drafts are working documents of the Internet Engineering 40 Task Force (IETF). Note that other groups may also distribute 41 working documents as Internet-Drafts. The list of current Internet- 42 Drafts is at https://datatracker.ietf.org/drafts/current/. 44 Internet-Drafts are draft documents valid for a maximum of six months 45 and may be updated, replaced, or obsoleted by other documents at any 46 time. It is inappropriate to use Internet-Drafts as reference 47 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on April 16, 2020. 50 Copyright Notice 52 Copyright (c) 2019 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents 57 (https://trustee.ietf.org/license-info) in effect on the date of 58 publication of this document. Please review these documents 59 carefully, as they describe your rights and restrictions with respect 60 to this document. Code Components extracted from this document must 61 include Simplified BSD License text as described in Section 4.e of 62 the Trust Legal Provisions and are provided without warranty as 63 described in the Simplified BSD License. 65 Table of Contents 67 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 68 2. Carrying TE Policy Information in BGP . . . . . . . . . . . . 5 69 3. TE Policy NLRI . . . . . . . . . . . . . . . . . . . . . . . 6 70 4. TE Policy Descriptors . . . . . . . . . . . . . . . . . . . . 7 71 4.1. Tunnel Identifier (Tunnel ID) . . . . . . . . . . . . . . 8 72 4.2. LSP Identifier (LSP ID) . . . . . . . . . . . . . . . . . 8 73 4.3. IPv4/IPv6 Tunnel Head-End Address . . . . . . . . . . . . 9 74 4.4. IPv4/IPv6 Tunnel Tail-End Address . . . . . . . . . . . . 9 75 4.5. SR Policy Candidate Path Descriptor . . . . . . . . . . . 10 76 4.6. Local MPLS Cross Connect . . . . . . . . . . . . . . . . 11 77 4.6.1. MPLS Cross Connect Interface . . . . . . . . . . . . 13 78 4.6.2. MPLS Cross Connect FEC . . . . . . . . . . . . . . . 14 79 5. MPLS-TE Policy State TLV . . . . . . . . . . . . . . . . . . 15 80 5.1. RSVP Objects . . . . . . . . . . . . . . . . . . . . . . 16 81 5.2. PCEP Objects . . . . . . . . . . . . . . . . . . . . . . 17 82 6. SR Policy State TLVs . . . . . . . . . . . . . . . . . . . . 18 83 6.1. SR Binding SID . . . . . . . . . . . . . . . . . . . . . 18 84 6.2. SR Candidate Path State . . . . . . . . . . . . . . . . . 20 85 6.3. SR Candidate Path Name . . . . . . . . . . . . . . . . . 22 86 6.4. SR Candidate Path Constraints . . . . . . . . . . . . . . 22 87 6.4.1. SR Affinity Constraint . . . . . . . . . . . . . . . 24 88 6.4.2. SR SRLG Constraint . . . . . . . . . . . . . . . . . 25 89 6.4.3. SR Bandwidth Constraint . . . . . . . . . . . . . . . 26 90 6.4.4. SR Disjoint Group Constraint . . . . . . . . . . . . 26 91 6.5. SR Segment List . . . . . . . . . . . . . . . . . . . . . 28 92 6.6. SR Segment . . . . . . . . . . . . . . . . . . . . . . . 31 93 6.6.1. Segment Descriptors . . . . . . . . . . . . . . . . . 32 94 6.7. SR Segment List Metric . . . . . . . . . . . . . . . . . 39 95 7. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 41 96 8. Manageability Considerations . . . . . . . . . . . . . . . . 41 97 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 42 98 9.1. BGP-LS NLRI-Types . . . . . . . . . . . . . . . . . . . . 42 99 9.2. BGP-LS Protocol-IDs . . . . . . . . . . . . . . . . . . . 42 100 9.3. BGP-LS TLVs . . . . . . . . . . . . . . . . . . . . . . . 42 101 9.4. BGP-LS SR Policy Protocol Origin . . . . . . . . . . . . 43 102 9.5. BGP-LS TE State Object Origin . . . . . . . . . . . . . . 44 103 9.6. BGP-LS TE State Address Family . . . . . . . . . . . . . 44 104 9.7. BGP-LS SR Segment Descriptors . . . . . . . . . . . . . . 44 105 9.8. BGP-LS Metric Type . . . . . . . . . . . . . . . . . . . 45 106 10. Security Considerations . . . . . . . . . . . . . . . . . . . 45 107 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 46 108 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 46 109 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 46 110 13.1. Normative References . . . . . . . . . . . . . . . . . . 46 111 13.2. Informative References . . . . . . . . . . . . . . . . . 48 112 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 49 114 1. Introduction 116 In many network environments, traffic engineering (TE) policies are 117 instantiated into various forms: 119 o MPLS Traffic Engineering Label Switched Paths (TE-LSPs). 121 o IP based tunnels (IP in IP, GRE, etc). 123 o Segment Routing (SR) Policies as defined in 124 [I-D.ietf-spring-segment-routing-policy] 126 o Local MPLS cross-connect configuration 128 All this information can be grouped into the same term: TE Policies. 129 In the rest of this document we refer to TE Policies as the set of 130 information related to the various instantiation of polices: MPLS TE 131 LSPs, IP tunnels (IPv4 or IPv6), SR Policies, etc. 133 TE Polices are generally instantiated at the head-end and are based 134 on either local configuration or controller based programming of the 135 node using various APIs and protocols, e.g., PCEP or BGP. 137 In many network environments, the configuration and state of each TE 138 Policy that is available in the network is required by a controller 139 which allows the network operator to optimize several functions and 140 operations through the use of a controller aware of both topology and 141 state information. 143 One example of a controller is the stateful Path Computation Element 144 (PCE) [RFC8231], which could provide benefits in path reoptimization. 145 While some extensions are proposed in Path Computation Element 146 Communication Protocol (PCEP) for the Path Computation Clients (PCCs) 147 to report the LSP states to the PCE, this mechanism may not be 148 applicable in a management-based PCE architecture as specified in 149 section 5.5 of [RFC4655]. As illustrated in the figure below, the 150 PCC is not an LSR in the routing domain, thus the head-end nodes of 151 the TE-LSPs may not implement the PCEP protocol. In this case a 152 general mechanism to collect the TE-LSP states from the ingress LERs 153 is needed. This document proposes an TE Policy state collection 154 mechanism complementary to the mechanism defined in [RFC8231]. 156 ----------- 157 | ----- | 158 Service | | TED |<-+-----------> 159 Request | ----- | TED synchronization 160 | | | | mechanism (for example, 161 v | | | routing protocol) 162 ------------- Request/ | v | 163 | | Response| ----- | 164 | NMS |<--------+> | PCE | | 165 | | | ----- | 166 ------------- ----------- 167 Service | 168 Request | 169 v 170 ---------- Signaling ---------- 171 | Head-End | Protocol | Adjacent | 172 | Node |<---------->| Node | 173 ---------- ---------- 175 Figure 1. Management-Based PCE Usage 177 In networks with composite PCE nodes as specified in section 5.1 of 178 [RFC4655], PCE is implemented on several routers in the network, and 179 the PCCs in the network can use the mechanism described in [RFC8231] 180 to report the TE Policy information to the PCE nodes. An external 181 component may also need to collect the TE Policy information from all 182 the PCEs in the network to obtain a global view of the LSP state in 183 the network. 185 In multi-area or multi-AS scenarios, each area or AS can have a child 186 PCE to collect the TE Policies in its own domain, in addition, a 187 parent PCE needs to collect TE Policy information from multiple child 188 PCEs to obtain a global view of LSPs inside and across the domains 189 involved. 191 In another network scenario, a centralized controller is used for 192 service placement. Obtaining the TE Policy state information is 193 quite important for making appropriate service placement decisions 194 with the purpose to both meet the application's requirements and 195 utilize network resources efficiently. 197 The Network Management System (NMS) may need to provide global 198 visibility of the TE Policies in the network as part of the network 199 visualization function. 201 BGP has been extended to distribute link-state and traffic 202 engineering information to external components [RFC7752]. Using the 203 same protocol to collect Traffic Engineering Policy and state 204 information is desirable for these external components since this 205 avoids introducing multiple protocols for network information 206 collection. This document describes a mechanism to distribute 207 traffic engineering policy information (MPLS, SR, IPv4 and IPv6) to 208 external components using BGP-LS. 210 2. Carrying TE Policy Information in BGP 212 TE Policy information is advertised in BGP UPDATE messages using the 213 MP_REACH_NLRI and MP_UNREACH_NLRI attributes [RFC4760]. The "Link- 214 State NLRI" defined in [RFC7752] is extended to carry the TE Policy 215 information. BGP speakers that wish to exchange TE Policy 216 information MUST use the BGP Multiprotocol Extensions Capability Code 217 (1) to advertise the corresponding (AFI, SAFI) pair, as specified in 218 [RFC4760]. New TLVs carried in the Link_State Attribute defined in 219 [RFC7752] are also defined in order to carry the attributes of a TE 220 Policy in the subsequent sections. 222 The format of "Link-State NLRI" is defined in [RFC7752] as follows: 224 0 1 2 3 225 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 226 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 227 | NLRI Type | Total NLRI Length | 228 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 229 | | 230 // Link-State NLRI (variable) // 231 | | 232 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 234 A new "NLRI Type" is defined for TE Policy Information as following: 236 o NLRI Type: TE Policy NLRI value 5. 238 The format of this new NLRI type is defined in Section 3 below. 240 3. TE Policy NLRI 242 This document defines the new TE Policy NLRI-Type and its format as 243 shown in the following figure: 245 0 1 2 3 246 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 1 247 +-+-+-+-+-+-+-+-+ 248 | Protocol-ID | 249 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 250 | Identifier | 251 | (64 bits) | 252 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 253 // Headend (Node Descriptors) // 254 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 255 // TE Policy Descriptors (variable) // 256 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 258 where: 260 o Protocol-ID field specifies the component that owns the TE Policy 261 state in the advertising node. The following new Protocol-IDs are 262 defined and apply to the TE Policy NLRI: 264 +-------------+----------------------------------+ 265 | Protocol-ID | NLRI information source protocol | 266 +-------------+----------------------------------+ 267 | 8 | RSVP-TE | 268 | 9 | Segment Routing | 269 +-------------+----------------------------------+ 271 o "Identifier" is an 8 octet value as defined in [RFC7752]. 273 o "Headend" consists of a Local Node Descriptor (TLV 256) as defined 274 in [RFC7752]. 276 o "TE Policy Descriptors" consists of one or more of the TLVs listed 277 as below: 279 +-----------+----------------------------------+ 280 | Codepoint | Descriptor TLVs | 281 +-----------+----------------------------------+ 282 | 550 | Tunnel ID | 283 | 551 | LSP ID | 284 | 552 | IPv4/6 Tunnel Head-end address | 285 | 553 | IPv4/6 Tunnel Tail-end address | 286 | 554 | SR Policy Candidate Path | 287 | 555 | Local MPLS Cross Connect | 288 +-----------+----------------------------------+ 290 The Local Node Descriptor TLV MUST include the following Node 291 Descriptor TLVs: 293 o BGP Router-ID (TLV 516) [I-D.ietf-idr-bgpls-segment-routing-epe], 294 which contains a valid BGP Identifier of the local node. 296 o Autonomous System Number (TLV 512) [RFC7752], which contains the 297 ASN or AS Confederation Identifier (ASN) [RFC5065], if 298 confederations are used, of the local node. 300 The Local Node Descriptor TLV SHOULD include the following Node 301 Descriptor TLVs: 303 o IPv4 Router-ID of Local Node (TLV 1028) [RFC7752], which contains 304 the IPv4 TE Router-ID of the local node when one is provisioned. 306 o IPv6 Router-ID of Local Node (TLV 1029) [RFC7752], which contains 307 the IPv6 TE Router-ID of the local node when one is provisioned. 309 The Local Node Descriptor TLV MAY include the following Node 310 Descriptor TLVs: 312 o Member-ASN (TLV 517) [I-D.ietf-idr-bgpls-segment-routing-epe], 313 which contains the ASN of the confederation member (i.e. Member- 314 AS Number), if BGP confederations are used, of the local node. 316 o Node Descriptors as defined in [RFC7752]. 318 4. TE Policy Descriptors 320 This sections defines the TE Policy Descriptors TLVs which are used 321 to describe the TE Policy being advertised by using the new BGP-LS TE 322 Policy NLRI type defined in Section 3. 324 4.1. Tunnel Identifier (Tunnel ID) 326 The Tunnel Identifier TLV contains the Tunnel ID defined in [RFC3209] 327 and is used for RSVP-TE protocol TE Policies. It has the following 328 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 | Tunnel ID | 336 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 338 where: 340 o Type: 550 342 o Length: 2 octets. 344 o Tunnel ID: 2 octets as defined in [RFC3209]. 346 4.2. LSP Identifier (LSP ID) 348 The LSP Identifier TLV contains the LSP ID defined in [RFC3209] and 349 is used for RSVP-TE protocol TE Policies. It has the following 350 format: 352 0 1 2 3 353 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 1 354 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 355 | Type | Length | 356 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 357 | LSP ID | 358 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 360 where: 362 o Type: 551 364 o Length: 2 octets. 366 o LSP ID: 2 octets as defined in [RFC3209]. 368 4.3. IPv4/IPv6 Tunnel Head-End Address 370 The IPv4/IPv6 Tunnel Head-End Address TLV contains the Tunnel Head- 371 End Address defined in [RFC3209] and is used for RSVP-TE protocol TE 372 Policies. It has following format: 374 0 1 2 3 375 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 1 376 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 377 | Type | Length | 378 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 379 // IPv4/IPv6 Tunnel Head-End Address (variable) // 380 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 382 where: 384 o Type: 552 386 o Length: 4 or 16 octets. 388 When the IPv4/IPv6 Tunnel Head-end Address TLV contains an IPv4 389 address, its length is 4 (octets). 391 When the IPv4/IPv6 Tunnel Head-end Address TLV contains an IPv6 392 address, its length is 16 (octets). 394 4.4. IPv4/IPv6 Tunnel Tail-End Address 396 The IPv4/IPv6 Tunnel Tail-End Address TLV contains the Tunnel Tail- 397 End Address defined in [RFC3209] and is used for RSVP-TE protocol TE 398 Policies. It has following format: 400 0 1 2 3 401 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 1 402 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 403 | Type | Length | 404 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 405 // IPv4/IPv6 Tunnel Tail-End Address (variable) // 406 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 408 where: 410 o Type: 553 412 o Length: 4 or 16 octets. 414 When the IPv4/IPv6 Tunnel Tail-end Address TLV contains an IPv4 415 address, its length is 4 (octets). 417 When the IPv4/IPv6 Tunnel Tail-end Address TLV contains an IPv6 418 address, its length is 16 (octets). 420 4.5. SR Policy Candidate Path Descriptor 422 The SR Policy Candidate Path Descriptor TLV identifies a Segment 423 Routing Policy candidate path (CP) as defined in 424 [I-D.ietf-spring-segment-routing-policy] and has the following 425 format: 427 0 1 2 3 428 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 1 429 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 430 | Type | Length | 431 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 432 |Protocol-origin| Flags | RESERVED | 433 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 434 | Endpoint (4 or 16 octets) // 435 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 436 | Policy Color (4 octets) | 437 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 438 | Originator AS Number (4 octets) | 439 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 440 | Originator Address (4 or 16 octets) // 441 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 442 | Discriminator (4 octets) | 443 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 445 where: 447 o Type: 554 449 o Length: variable (valid values are 24, 36 or 48 octets) 451 o Protocol-Origin : 1 octet field which identifies the protocol or 452 component which is responsible for the instantiation of this path. 453 Following protocol-origin codepoints are defined in this document. 455 +------------+---------------------------------------------------------+ 456 | Code Point | Protocol Origin | 457 +------------+---------------------------------------------------------+ 458 | 1 | PCEP | 459 | 2 | BGP SR Policy | 460 | 3 | Local (via CLI, Yang model through NETCONF, gRPC, etc.) | 461 +------------+---------------------------------------------------------+ 462 o Flags: 1 octet field with following bit positions defined. Other 463 bits SHOULD be cleared by originator and MUST be ignored by 464 receiver. 466 0 1 2 3 4 5 6 7 467 +-+-+-+-+-+-+-+-+ 468 |E|O| | 469 +-+-+-+-+-+-+-+-+ 471 where: 473 * E-Flag : Indicates the encoding of endpoint as IPv6 address 474 when set and IPv4 address when clear 476 * O-Flag : Indicates the encoding of originator address as IPv6 477 address when set and IPv4 address when clear 479 o Reserved : 2 octets which SHOULD be set to 0 by originator and 480 MUST be ignored by receiver. 482 o Endpoint : 4 or 16 octets (as indicated by the flags) containing 483 the address of the endpoint of the SR Policy 485 o Color : 4 octets that indicates the color of the SR Policy 487 o Originator ASN : 4 octets to carry the 4 byte encoding of the ASN 488 of the originator. Refer [I-D.ietf-spring-segment-routing-policy] 489 Sec 2.4 for details. 491 o Originator Address : 4 or 16 octets (as indicated by the flags) to 492 carry the address of the originator. Refer 493 [I-D.ietf-spring-segment-routing-policy] Sec 2.4 for details. 495 o Discriminator : 4 octets to carry the discrimator of the path. 496 Refer [I-D.ietf-spring-segment-routing-policy] Sec 2.5 for 497 details. 499 4.6. Local MPLS Cross Connect 501 The Local MPLS Cross Connect TLV identifies a local MPLS state in the 502 form of incoming label and interface followed by an outgoing label 503 and interface. Outgoing interface may appear multiple times (for 504 multicast states). It is used with Protocol ID set to "Static 505 Configuration" value 5 as defined in [RFC7752]. 507 The Local MPLS Cross Connect TLV has the following format: 509 0 1 2 3 510 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 511 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 512 | Type | Length | 513 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 514 | Incoming label (4 octets) | 515 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 516 | Outgoing label (4 octets) | 517 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 518 // Sub-TLVs (variable) // 519 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 521 where: 523 o Type: 555 525 o Length: variable. 527 o Incoming and Outgoing labels: 4 octets each. 529 o Sub-TLVs: following Sub-TLVs are defined: 531 * Interface Sub-TLV 533 * Forwarding Equivalent Class (FEC) 535 The Local MPLS Cross Connect TLV: 537 MUST have an incoming label. 539 MUST have an outgoing label. 541 MAY contain an Interface Sub-TLV having the I-flag set. 543 MUST contain at least one Interface Sub-TLV having the I-flag 544 unset. 546 MAY contain multiple Interface Sub-TLV having the I-flag unset. 547 This is the case of a multicast MPLS cross connect. 549 MAY contain a FEC Sub-TLV. 551 The following sub-TLVs are defined for the Local MPLS Cross Connect 552 TLV: 554 +-----------+----------------------------------+ 555 | Codepoint | Descriptor TLV | 556 +-----------+----------------------------------+ 557 | 556 | MPLS Cross Connect Interface | 558 | 557 | MPLS Cross Connect FEC | 559 +-----------+----------------------------------+ 561 These are defined in the following sub-sections. 563 4.6.1. MPLS Cross Connect Interface 565 The MPLS Cross Connect Interface sub-TLV is optional and contains the 566 identifier of the interface (incoming or outgoing) in the form of an 567 IPv4 address or an IPv6 address. 569 The MPLS Cross Connect Interface sub-TLV has the following format: 571 0 1 2 3 572 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 1 573 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 574 | Type | Length | 575 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 577 +-+-+-+-+-+-+-+-+ 578 | Flags | 579 +-+-+-+-+-+-+-+-+ 581 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 582 | Local Interface Identifier (4 octets) | 583 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 584 // Interface Address (4 or 16 octets) // 585 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 587 where: 589 o Type: 556 591 o Length: 9 or 21. 593 o Flags: 1 octet of flags defined as follows: 595 0 1 2 3 4 5 6 7 596 +-+-+-+-+-+-+-+-+ 597 |I| | 598 +-+-+-+-+-+-+-+-+ 600 where: 602 * I-Flag is the Interface flag. When set, the Interface Sub-TLV 603 describes an incoming interface. If the I-flag is not set, 604 then the Interface Sub-TLV describes an outgoing interface. 606 o Local Interface Identifier: a 4 octet identifier. 608 o Interface address: a 4 octet IPv4 address or a 16 octet IPv6 609 address. 611 4.6.2. MPLS Cross Connect FEC 613 The MPLS Cross Connect FEC sub-TLV is optional and contains the FEC 614 associated to the incoming label. 616 The MPLS Cross Connect FEC sub-TLV has the following format: 618 0 1 2 3 619 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 1 620 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 621 | Type | Length | 622 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 623 | Flags | Masklength | Prefix (variable) // 624 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 625 // Prefix (variable) // 626 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 628 where: 630 o Type: 557 632 o Length: variable. 634 o Flags: 1 octet of flags defined as follows: 636 0 1 2 3 4 5 6 7 637 +-+-+-+-+-+-+-+-+ 638 |4| | 639 +-+-+-+-+-+-+-+-+ 641 where: 643 * 4-Flag is the IPv4 flag. When set, the FEC Sub-TLV describes 644 an IPv4 FEC. If the 4-flag is not set, then the FEC Sub-TLV 645 describes an IPv6 FEC. 647 o Mask Length: 1 octet of prefix length. 649 o Prefix: an IPv4 or IPv6 prefix whose mask length is given by the " 650 Mask Length" field padded to an octet boundary. 652 5. MPLS-TE Policy State TLV 654 A new TLV called "MPLS-TE Policy State TLV", is used to describe the 655 characteristics of the MPLS-TE Policy and it is carried in the 656 optional non-transitive BGP Attribute "LINK_STATE Attribute" defined 657 in [RFC7752]. These MPLS-TE Policy characteristics include the 658 characteristics and attributes of the policy, its dataplane, explicit 659 path, Quality of Service (QoS) parameters, route information, the 660 protection mechanisms, etc. 662 The MPLS-TE Policy State TLV has the following format: 664 0 1 2 3 665 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 1 666 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 667 | Type | Length | 668 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 669 | Object-origin | Address Family| RESERVED | 670 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 672 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 673 // MPLS-TE Policy State Objects (variable) // 674 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 676 where: 678 MPLS-TE Policy State TLV 680 o Type: 1200 682 o Length: the total length of the MPLS-TE Policy State TLV not 683 including Type and Length fields. 685 o Object-origin: identifies the component (or protocol) from which 686 the contained object originated. This allows for objects defined 687 in different components to be collected while avoiding the 688 possible codepoint collisions among these components. Following 689 object-origin codepoints are defined in this document. 691 +----------+------------------+ 692 | Code | Object | 693 | Point | Origin | 694 +----------+------------------+ 695 | 1 | RSVP-TE | 696 | 2 | PCEP | 697 | 3 | Local/Static | 698 +----------+------------------+ 700 o Address Family: describes the address family used to setup the 701 MPLS-TE policy. The following address family values are defined 702 in this document: 704 +----------+------------------+ 705 | Code | Dataplane | 706 | Point | | 707 +----------+------------------+ 708 | 1 | MPLS-IPv4 | 709 | 2 | MPLS-IPv6 | 710 +----------+------------------+ 712 o RESERVED: 16-bit field. SHOULD be set to 0 on transmission and 713 MUST be ignored on receipt. 715 o TE Policy State Objects: Rather than replicating all these objects 716 in this document, the semantics and encodings of the objects as 717 defined in RSVP-TE and PCEP are reused. 719 The state information is carried in the "MPLS-TE Policy State 720 Objects" with the following format as described in the sub-sections 721 below. 723 5.1. RSVP Objects 725 RSVP-TE objects are encoded in the "MPLS-TE Policy State Objects" 726 field of the MPLS-TE Policy State TLV and consists of MPLS TE LSP 727 objects defined in RSVP-TE [RFC3209] [RFC3473]. Rather than 728 replicating all MPLS TE LSP related objects in this document, the 729 semantics and encodings of the MPLS TE LSP objects are re-used. 730 These MPLS TE LSP objects are carried in the MPLS-TE Policy State 731 TLV. 733 When carrying RSVP-TE objects, the "Object-Origin" field is set to 734 "RSVP-TE". 736 The following RSVP-TE Objects are defined: 738 o SENDER_TSPEC and FLOW_SPEC [RFC2205] 739 o SESSION_ATTRIBUTE [RFC3209] 741 o EXPLICIT_ROUTE Object (ERO) [RFC3209] 743 o ROUTE_RECORD Object (RRO) [RFC3209] 745 o FAST_REROUTE Object [RFC4090] 747 o DETOUR Object [RFC4090] 749 o EXCLUDE_ROUTE Object (XRO) [RFC4874] 751 o SECONDARY_EXPLICIT_ROUTE Object (SERO) [RFC4873] 753 o SECONDARY_RECORD_ROUTE (SRRO) [RFC4873] 755 o LSP_ATTRIBUTES Object [RFC5420] 757 o LSP_REQUIRED_ATTRIBUTES Object [RFC5420] 759 o PROTECTION Object [RFC3473][RFC4872][RFC4873] 761 o ASSOCIATION Object [RFC4872] 763 o PRIMARY_PATH_ROUTE Object [RFC4872] 765 o ADMIN_STATUS Object [RFC3473] 767 o LABEL_REQUEST Object [RFC3209][RFC3473] 769 For the MPLS TE LSP Objects listed above, the corresponding sub- 770 objects are also applicable to this mechanism. Note that this list 771 is not exhaustive, other MPLS TE LSP objects which reflect specific 772 characteristics of the MPLS TE LSP can also be carried in the LSP 773 state TLV. 775 5.2. PCEP Objects 777 PCEP objects are encoded in the "MPLS-TE Policy State Objects" field 778 of the MPLS-TE Policy State TLV and consists of PCEP objects defined 779 in [RFC5440]. Rather than replicating all MPLS TE LSP related 780 objects in this document, the semantics and encodings of the MPLS TE 781 LSP objects are re-used. These MPLS TE LSP objects are carried in 782 the MPLS-TE Policy State TLV. 784 When carrying PCEP objects, the "Object-Origin" field is set to 785 "PCEP". 787 The following PCEP Objects are defined: 789 o METRIC Object [RFC5440] 791 o BANDWIDTH Object [RFC5440] 793 For the MPLS TE LSP Objects listed above, the corresponding sub- 794 objects are also applicable to this mechanism. Note that this list 795 is not exhaustive, other MPLS TE LSP objects which reflect specific 796 characteristics of the MPLS TE LSP can also be carried in the TE 797 Policy State TLV. 799 6. SR Policy State TLVs 801 Segment Routing Policy (SR Policy) architecture is specified in 802 [I-D.ietf-spring-segment-routing-policy]. A SR Policy can comprise 803 of one or more candidate paths (CP) of which at a given time one and 804 only one may be active (i.e. installed in forwarding and usable for 805 steering of traffic). Each CP in turn may have one or more SID-List 806 of which one or more may be active; when multiple are active then 807 traffic is load balanced over them. 809 This section defines the various TLVs which enable the headend to 810 report the state of an SR Policy, its CP(s), SID-List(s) and their 811 status. These TLVs are carried in the optional non-transitive BGP 812 Attribute "LINK_STATE Attribute" defined in [RFC7752] and enable the 813 same consistent form of reporting for SR Policy state irrespective of 814 the Protocol-Origin used to provision the policy. Detailed procedure 815 is described in Section 7 . 817 6.1. SR Binding SID 819 The SR Binding SID (BSID) is an optional TLV that provides the BSID 820 and its attributes for the SR Policy CP. The TLV MAY also optionally 821 contain the Provisioned BSID value for reporting when explicitly 822 provisioned. 824 The TLV has the following format: 826 0 1 2 3 827 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 1 828 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 829 | Type | Length | 830 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 831 | BSID Flags | RESERVED | 832 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 833 | Binding SID (4 or 16 octets) // 834 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 835 | Provisioned Binding SID (4 or 16 octets) // 836 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 838 where: 840 o Type: 1201 842 o Length: variable (valid values are 12 or 36 octets) 844 o BSID Flags: 2 octet field that indicates attribute and status of 845 the Binding SID (BSID) associated with this CP. The following bit 846 positions are defined and the semantics are described in detail in 847 [I-D.ietf-spring-segment-routing-policy]. Other bits SHOULD be 848 cleared by originator and MUST be ignored by receiver. 850 0 1 851 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 852 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 853 |D|B|U|L|F| | 854 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 856 where: 858 * D-Flag : Indicates the dataplane for the BSIDs and if they are 859 16 octet SRv6 SID when set and are 4 octet SR/MPLS label value 860 when clear. 862 * B-Flag : Indicates the allocation of the value in the BSID 863 field when set and indicates that BSID is not allocated when 864 clear. 866 * U-Flag : Indicates the provisioned BSID value is unavailable 867 when set. 869 * L-Flag : Indicates the BSID value is from the Segment Routing 870 Local Block (SRLB) of the headend node when set and is from the 871 local dynamic label pool when clear 873 * F-Flag : Indicates the BSID value is one allocated from dynamic 874 label pool due to fallback (e.g. when specified BSID is 875 unavailable) when set. 877 o RESERVED: 2 octets. SHOULD be set to 0 by originator and MUST be 878 ignored by receiver. 880 o Binding SID: It indicates the operational or allocated BSID value 881 for the CP based on the status flags. 883 o Provisioned BSID: It is used to report the explicitly provisioned 884 BSID value regardless of whether it is successfully allocated or 885 not. The field is set to value 0 when BSID has not been specified 886 or provisioned for the CP. 888 The BSID fields above are 4 octet carrying the MPLS Label or 16 889 octets carrying the SRv6 SID based on the BSID D-flag. When carrying 890 the MPLS Label, as shown in the figure below, the TC, S and TTL 891 (total of 12 bits) are RESERVED and SHOULD be set to 0 by originator 892 and MUST be ignored by the receiver. 894 0 1 2 3 895 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 1 896 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 897 | Label | TC |S| TTL | 898 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 900 6.2. SR Candidate Path State 902 The SR Candidate Path (CP) State TLV provides the operational status 903 and attributes of the SR Policy at the CP level. The TLV has the 904 following format: 906 0 1 2 3 907 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 1 908 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 909 | Type | Length | 910 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 911 | Priority | RESERVED | Flags | 912 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 913 | Preference (4 octets) | 914 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 916 where: 918 o Type: 1202 919 o Length: 8 octets 921 o Priority : 1 octet value which indicates the priority of the CP. 922 Refer Section 2.12 of [I-D.ietf-spring-segment-routing-policy]. 924 o RESERVED: 1 octet. SHOULD be set to 0 by originator and MUST be 925 ignored by receiver. 927 o Flags: 2 octet field that indicates attribute and status of the 928 CP. The following bit positions are defined and the semantics are 929 described in detail in [I-D.ietf-spring-segment-routing-policy]. 930 Other bits SHOULD be cleared by originator and MUST be ignored by 931 receiver. 933 0 1 934 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 935 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 936 |S|A|B|E|V|O|D|C|I|T| | 937 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 939 where: 941 * S-Flag : Indicates the CP is in administrative shut state when 942 set 944 * A-Flag : Indicates the CP is the active path (i.e. one 945 provisioned in the forwarding plane) for the SR Policy when set 947 * B-Flag : Indicates the CP is the backup path (i.e. one 948 identified for path protection of the active path) for the SR 949 Policy when set 951 * E-Flag : Indicates that the CP has been evaluated for validity 952 (e.g. headend may evaluate CPs based on their preferences) when 953 set 955 * V-Flag : Indicates the CP has at least one valid SID-List when 956 set. When the E-Flag is clear (i.e. the CP has not been 957 evaluated), then this flag MUST be set to 0 by the originator 958 and ignored by the receiver. 960 * O-Flag : Indicates the CP was instantiated by the headend due 961 to an on-demand-nexthop trigger based on local template when 962 set. Refer Section 8.5 of 963 [I-D.ietf-spring-segment-routing-policy]. 965 * D-Flag : Indicates the CP was delegated for computation to a 966 PCE/controller when set 968 * C-Flag : Indicates the CP was provisioned by a PCE/controller 969 when set 971 * I-Flag : Indicates the CP will perform the "drop upon invalid" 972 behavior when no other active path is available for this SR 973 Policy and this path is the one with best preference amongst 974 the available CPs. Refer Section 8.2 of 975 [I-D.ietf-spring-segment-routing-policy]. 977 * T-Flag : Indicates the CP has been marked as eligible for use 978 as Transit Policy on the headend when set. Refer Section 8.3 979 of [I-D.ietf-spring-segment-routing-policy]. 981 o Preference : 4 octet value which indicates the preference of the 982 CP. Refer Section 2.7 of 983 [I-D.ietf-spring-segment-routing-policy]. 985 6.3. SR Candidate Path Name 987 The SR Candidate Path Name TLV is an optional TLV that is used to 988 carry the symbolic name associated with the candidate path. The TLV 989 has the following format: 991 0 1 2 3 992 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 1 993 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 994 | Type | Length | 995 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 996 | Candidate Path Symbolic Name (variable) // 997 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 999 where: 1001 o Type: 1203 1003 o Length: variable 1005 o CP Name : Symbolic name for the CP. It is a string of printable 1006 ASCII characters without a NULL terminator. 1008 6.4. SR Candidate Path Constraints 1010 The SR Candidate Path Constraints TLV is an optional TLV that is used 1011 to report the constraints associated with the candidate path. The 1012 constraints are generally applied to a dynamic candidate path which 1013 is computed by the headend. The constraints may also be applied to 1014 an explicit path where the headend is expected to validate that the 1015 path expresses satisfies the specified constraints and the path is to 1016 be invalidated by the headend when the constraints are no longer met 1017 (e.g. due to topology changes). 1019 The TLV has the following format: 1021 0 1 2 3 1022 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 1023 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1024 | Type | Length | 1025 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1026 | Flags | RESERVED | 1027 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1028 | MTID | Algorithm | RESERVED | 1029 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1030 | sub-TLVs (variable) // 1031 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1033 where: 1035 o Type: 1204 1037 o Length: variable 1039 o Flags: 2 octet field that indicates the constraints that are being 1040 applied to the CP. The following bit positions are defined and 1041 the other bits SHOULD be cleared by originator and MUST be ignored 1042 by receiver. 1044 0 1 1045 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 1046 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1047 |D|P|U|A|T| | 1048 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1050 where: 1052 * D-Flag : Indicates that the CP needs to use SRv6 dataplane when 1053 set and SR/MPLS dataplane when clear 1055 * P-Flag : Indicates that the CP needs to use only protected SIDs 1056 when set 1058 * U-Flag : Indicates that the CP needs to use only unprotected 1059 SIDs when set 1061 * A-Flag : Indicates that the CP needs to use the SIDs belonging 1062 to the specified SR Algorithm only when set 1064 * T-Flag: Indicates that the CP needs to use the SIDs belonging 1065 to the specified topology only when set 1067 o RESERVED: 2 octet. SHOULD be set to 0 by originator and MUST be 1068 ignored by receiver. 1070 o MTID : Indicates the multi-topology identifier of the IGP topology 1071 that is preferred to be used when the path is setup. When the 1072 T-flag is set then the path is strictly useing the specified 1073 topology SIDs only. 1075 o Algorithm : Indicates the algorithm that is preferred to be used 1076 when the path is setup. When the A-flag is set then the path is 1077 strictly using the specified algorithm SIDs only. 1079 o RESERVED: 1 octet. SHOULD be set to 0 by originator and MUST be 1080 ignored by receiver. 1082 o sub-TLVs: optional sub-TLVs MAY be included in this TLV to 1083 describe other constraints. 1085 The following constraint sub-TLVs are defined for the SR CP 1086 Constraints TLV. 1088 6.4.1. SR Affinity Constraint 1090 The SR Affinity Constraint sub-TLV is an optional sub-TLV that is 1091 used to carry the affinity constraints [RFC2702] associated with the 1092 candidate path. The affinity is expressed in terms of Extended Admin 1093 Group (EAG) as defined in [RFC7308]. The TLV has the following 1094 format: 1096 0 1 2 3 1097 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 1098 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1099 | Type | Length | 1100 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1101 | Excl-Any-Size | Incl-Any-Size | Incl-All-Size | RESERVED | 1102 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1103 | Exclude-Any EAG (optional, variable) // 1104 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1105 | Include-Any EAG (optional, variable) // 1106 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1107 | Include-All EAG (optional, variable) // 1108 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1110 where: 1112 o Type: 1208 1114 o Length: variable, dependent on the size of the Extended Admin 1115 Group. MUST be a multiple of 4 octets. 1117 o Exclude-Any-Size : one octet to indicate the size of Exclude-Any 1118 EAG bitmask size in multiples of 4 octets. (e.g. value 0 1119 indicates the Exclude-Any EAG field is skipped, value 1 indicates 1120 that 4 octets of Exclude-Any EAG is included) 1122 o Include-Any-Size : one octet to indicate the size of Include-Any 1123 EAG bitmask size in multiples of 4 octets. (e.g. value 0 1124 indicates the Include-Any EAG field is skipped, value 1 indicates 1125 that 4 octets of Include-Any EAG is included) 1127 o Include-All-Size : one octet to indicate the size of Include-All 1128 EAG bitmask size in multiples of 4 octets. (e.g. value 0 1129 indicates the Include-All EAG field is skipped, value 1 indicates 1130 that 4 octets of Include-All EAG is included) 1132 o RESERVED: 1 octet. SHOULD be set to 0 by originator and MUST be 1133 ignored by receiver. 1135 o Exclude-Any EAG : the bitmask used to represent the affinities to 1136 be excluded from the path. 1138 o Include-Any EAG : the bitmask used to represent the affinities to 1139 be included in the path. 1141 o Include-All EAG : the bitmask used to represent the all affinities 1142 to be included in the path. 1144 6.4.2. SR SRLG Constraint 1146 The SR SRLG Constraint sub-TLV is an optional sub-TLV that is used to 1147 carry the Shared Risk Link Group (SRLG) values [RFC4202] that are to 1148 be excluded from the candidate path. The TLV has the following 1149 format: 1151 0 1 2 3 1152 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 1153 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1154 | Type | Length | 1155 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1156 | SRLG Values (variable, multiples of 4 octets) // 1157 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1159 where: 1161 o Type: 1209 1163 o Length: variable, dependent on the number of SRLGs encoded. MUST 1164 be a multiple of 4 octets. 1166 o SRLG Values : One or more SRLG values (each of 4 octets). 1168 6.4.3. SR Bandwidth Constraint 1170 The SR Bandwidth Constraint sub-TLV is an optional sub-TLV that is 1171 used to indicate the desired bandwidth availability that needs to be 1172 ensured for the candidate path. The TLV has the following format: 1174 0 1 2 3 1175 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 1176 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1177 | Type | Length | 1178 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1179 | Bandwidth | 1180 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1182 where: 1184 o Type: 1210 1186 o Length: 4 octects 1188 o Bandwidth : 4 octets which specify the desired bandwidth in unit 1189 of bytes per second in IEEE floating point format. 1191 6.4.4. SR Disjoint Group Constraint 1193 The SR Disjoint Group Constraint sub-TLV is an optional sub-TLV that 1194 is used to carry the disjointness constraint associated with the 1195 candidate path. The disjointness between two SR Policy Candidate 1196 Paths is expressed by associating them with the same disjoint group 1197 identifier and then specifying the type of disjointness required 1198 between their paths. The computation is expected to achieve the 1199 highest level of disjointness requested and when that is not possible 1200 then fallback to a lesser level progressively based on the levels 1201 indicated. 1203 The TLV has the following format: 1205 0 1 2 3 1206 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 1207 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1208 | Type | Length | 1209 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1210 | Request-Flags | Status-Flags | RESERVED | 1211 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1212 | Disjoint Group Identifier | 1213 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1215 where: 1217 o Type: 1211 1219 o Length: 8 octets 1221 o Request Flags : one octet to indicate the level of disjointness 1222 requested as specified in the form of flags. The following flags 1223 are defined and the other bits SHOULD be cleared by originator and 1224 MUST be ignored by receiver. 1226 0 1 2 3 4 5 6 7 1227 +-+-+-+-+-+-+-+-+ 1228 |S|N|L|F|I| | 1229 +-+-+-+-+-+-+-+-+ 1231 where: 1233 * S-Flag : Indicates that SRLG disjointness is requested 1235 * N-Flag : Indicates that node disjointness is requested when 1237 * L-Flag : Indicates that link disjointness is requested when 1239 * F-Flag : Indicates that the computation may fallback to a lower 1240 level of disjointness amongst the ones requested when all 1241 cannot be achieved 1243 * I-Flag : Indicates that the computation may fallback to the 1244 default best path (e.g. IGP path) in case of none of the 1245 desired disjointness can be achieved. 1247 o Status Flags : one octet to indicate the level of disjointness 1248 that has been achieved by the computation as specified in the form 1249 of flags. The following flags are defined and the other bits 1250 SHOULD be cleared by originator and MUST be ignored by receiver. 1252 0 1 2 3 4 5 6 7 1253 +-+-+-+-+-+-+-+-+ 1254 |S|N|L|F|I|X| | 1255 +-+-+-+-+-+-+-+-+ 1257 where: 1259 * S-Flag : Indicates that SRLG disjointness is achieved 1261 * N-Flag : Indicates that node disjointness is achieved 1263 * L-Flag : Indicates that link disjointness is achieved 1265 * F-Flag : Indicates that the computation has fallen back to a 1266 lower level of disjointness that requested. 1268 * I-Flag : Indicates that the computation has fallen back to the 1269 best path (e.g. IGP path) and disjointness has not been 1270 achieved 1272 * X-Flag : Indicates that the disjointness constraint could not 1273 be achieved and hence path has been invalidated 1275 o RESERVED: 2 octets. SHOULD be set to 0 by originator and MUST be 1276 ignored by receiver. 1278 o Disjointness Group Identifier : 4 octet value that is the group 1279 identifier for a set of disjoint paths 1281 6.5. SR Segment List 1283 The SR Segment List TLV is used to report the SID-List(s) of a 1284 candidate path. The TLV has following format: 1286 0 1 2 3 1287 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 1288 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1289 | Type | Length | 1290 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1291 | Flags | RESERVED | 1292 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1293 | MTID | Algorithm | RESERVED | 1294 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1295 | Weight (4 octets) | 1296 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1297 | sub-TLVs (variable) // 1298 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1300 where: 1302 o Type: 1205 1304 o Length: variable 1306 o Flags: 2 octet field that indicates attribute and status of the 1307 SID-List.The following bit positions are defined and the semantics 1308 are described in detail in 1309 [I-D.ietf-spring-segment-routing-policy]. Other bits SHOULD be 1310 cleared by originator and MUST be ignored by receiver. 1312 0 1 1313 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 1314 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1315 |D|E|C|V|R|F|A|T|M| | 1316 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1318 where: 1320 * D-Flag : Indicates the SID-List is comprised of SRv6 SIDs when 1321 set and indicates it is comprised of SR/MPLS labels when clear. 1323 * E-Flag : Indicates that SID-List is an explicit path when set 1324 and indicates dynamic path when clear. 1326 * C-Flag : Indicates that SID-List has been computed for a 1327 dynamic path when set. It is always reported as set for 1328 explicit paths. 1330 * V-Flag : Indicates the SID-List has passed verification or its 1331 verification was not required when set and failed verification 1332 when clear. 1334 * R-Flag : Indicates that the first Segment has been resolved 1335 when set and failed resolution when clear. 1337 * F-Flag : Indicates that the computation for the dynamic path 1338 failed when set and succeeded (or not required in case of 1339 explicit path) when clear 1341 * A-Flag : Indicates that all the SIDs in the SID-List belong to 1342 the specified algorithm when set. 1344 * T-Flag : Indicates that all the SIDs in the SID-List belong to 1345 the specified topology (identified by the multi-topology ID) 1346 when set. 1348 * M-Flag : Indicates that the SID-list has been removed from the 1349 forwarding plane due to fault detection by a monitoring 1350 mechanism (e.g. BFD) when set and indicates no fault detected 1351 or monitoring is not being done when clear. 1353 o RESERVED: 2 octet. SHOULD be set to 0 by originator and MUST be 1354 ignored by receiver. 1356 o MTID : 2 octet that indicates the multi-topology identifier of the 1357 IGP topology to be used when the T-flag is set. 1359 o Algorithm: 1 octet that indicates the algorithm of the SIDs used 1360 in the SID-List when the A-flag is set. 1362 o RESERVED: 1 octet. SHOULD be set to 0 by originator and MUST be 1363 ignored by receiver. 1365 o Weight: 4 octet field that indicates the weight associated with 1366 the SID-List for weighted load-balancing. Refer Section 2.2 and 1367 2.11 of [I-D.ietf-spring-segment-routing-policy]. 1369 o Sub-TLVs : variable and contains the ordered set of Segments and 1370 any other optional attributes associated with the specific SID- 1371 List. 1373 The SR Segment sub-TLV (defined in Section 6.6) MUST be included as 1374 an ordered set of sub-TLVs within the SR Segment List TLV when the 1375 SID-List is not empty. A SID-List may be empty in certain cases 1376 (e.g. for a dynamic path) where the headend has not yet performed the 1377 computation and hence not derived the segments required for the path; 1378 in such cases, the SR Segment List TLV SHOULD NOT include any SR 1379 Segment sub-TLVs. 1381 6.6. SR Segment 1383 The SR Segment sub-TLV describes a single segment in a SID-List. One 1384 or more instances of this sub-TLV in an ordered manner constitute a 1385 SID-List for a SR Policy candidate path. It is a sub-TLV of the SR 1386 Segment List TLV and has following format: 1388 0 1 2 3 1389 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 1390 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1391 | Type | Length | 1392 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1393 | Segment Type | RESERVED | Flags | 1394 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1395 | SID (4 or 16 octets) // 1396 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1397 // Segment Descriptor (variable) // 1398 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1399 // Sub-TLVs (variable) // 1400 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1402 where: 1404 o Type: 1206 1406 o Length: variable 1408 o Segment Type : 1 octet which indicates the type of segment (refer 1409 Section 6.6.1 for details) 1411 o RESERVED: 1 octet. SHOULD be set to 0 by originator and MUST be 1412 ignored by receiver. 1414 o Flags: 2 octet field that indicates attribute and status of the 1415 Segment and its SID. The following bit positions are defined and 1416 the semantics are described in detail in 1417 [I-D.ietf-spring-segment-routing-policy]. Other bits SHOULD be 1418 cleared by originator and MUST be ignored by receiver. 1420 0 1 1421 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 1422 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1423 |S|E|V|R|A| | 1424 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1426 where: 1428 * S-Flag : Indicates the presence of SID value in the SID field 1429 when set and that no value is indicated when clear. 1431 * E-Flag : Indicates the SID value is explicitly provisioned 1432 value (locally on headend or via controller/PCE) when set and 1433 is a dynamically resolved value by headend when clear 1435 * V-Flag : Indicates the SID has passed verification or did not 1436 require verification when set and failed verification when 1437 clear. 1439 * R-Flag : Indicates the SID has been resolved or did not require 1440 resolution (e.g. because it is not the first SID) when set and 1441 failed resolution when clear. 1443 * A-Flag : Indicates that the Algorithm indicated in the Segment 1444 descriptor is valid when set. When clear, it indicates that 1445 the headend is unable to determine the algorithm of the SID. 1447 o SID : 4 octet carrying the MPLS Label or 16 octets carrying the 1448 SRv6 SID based on the Segment Type. When carrying the MPLS Label, 1449 as shown in the figure below, the TC, S and TTL (total of 12 bits) 1450 are RESERVED and SHOULD be set to 0 by originator and MUST be 1451 ignored by the receiver. 1453 0 1 2 3 1454 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 1455 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1456 | Label | TC |S| TTL | 1457 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1459 o Segment Descriptor : variable size Segment descriptor based on the 1460 type of segment (refer Section 6.6.1 for details) 1462 o Sub-Sub-TLVs : variable and contains any other optional attributes 1463 associated with the specific SID-List. 1465 Currently no Sub-Sub-TLV of the SR Segment sub-TLV is defined. 1467 6.6.1. Segment Descriptors 1469 [I-D.ietf-spring-segment-routing-policy] section 4 defines multiple 1470 types of segments and their description. This section defines the 1471 encoding of the Segment Descriptors for each of those Segment types 1472 to be used in the Segment sub-TLV describes previously in 1473 Section 6.6. 1475 The following types are currently defined: 1477 +-------+--------------------------------------------------------------+ 1478 | Type | Segment Description | 1479 +-------+--------------------------------------------------------------+ 1480 | 0 | Invalid | 1481 | 1 | SR-MPLS Label | 1482 | 2 | SRv6 SID as IPv6 address | 1483 | 3 | SR-MPLS Prefix SID as IPv4 Node Address | 1484 | 4 | SR-MPLS Prefix SID as IPv6 Node Global Address | 1485 | 5 | SR-MPLS Adjacency SID as IPv4 Node Address & Local | 1486 | | Interface ID | 1487 | 6 | SR-MPLS Adjacency SID as IPv4 Local & Remote Interface | 1488 | | Addresses | 1489 | 7 | SR-MPLS Adjacency SID as pair of IPv6 Global Address & | 1490 | | Interface ID for Local & Remote nodes | 1491 | 8 | SR-MPLS Adjacency SID as pair of IPv6 Global Addresses for | 1492 | | the Local & Remote Interface | 1493 | 9 | SRv6 END SID as IPv6 Node Global Address | 1494 | 10 | SRv6 END.X SID as pair of IPv6 Global Address & Interface ID | 1495 | | for Local & Remote nodes | 1496 | 11 | SRv6 END.X SID as pair of IPv6 Global Addresses for the | 1497 | | Local & Remote Interface | 1498 +-------+--------------------------------------------------------------+ 1500 6.6.1.1. Type 1: SR-MPLS Label 1502 The Segment is SR-MPLS type and is specified simply as the label. 1503 The format of its Segment Descriptor is as follows: 1505 0 1 2 3 1506 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 1507 +-+-+-+-+-+-+-+-+ 1508 | Algorithm | 1509 +-+-+-+-+-+-+-+-+ 1511 Where: 1513 o Algorithm: 1 octet value that indicates the algorithm used for 1514 picking the SID. This is valid only when the A-flag has been set 1515 in the Segment TLV. 1517 6.6.1.2. Type 2: SRv6 SID 1519 The Segment is SRv6 type and is specified simply as the SRv6 SID 1520 address. The format of its Segment Descriptor is as follows: 1522 0 1 2 3 1523 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 1524 +-+-+-+-+-+-+-+-+ 1525 | Algorithm | 1526 +-+-+-+-+-+-+-+-+ 1528 Where: 1530 o Algorithm: 1 octet value that indicates the algorithm used for 1531 picking the SID. This is valid only when the A-flag has been set 1532 in the Segment TLV. 1534 6.6.1.3. Type 3: SR-MPLS Prefix SID for IPv4 1536 The Segment is SR-MPLS Prefix SID type and is specified as an IPv4 1537 node address. The format of its Segment Descriptor is as follows: 1539 0 1 2 3 1540 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 1541 +-+-+-+-+-+-+-+-+ 1542 | Algorithm | 1543 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1544 | IPv4 Node Address (4 octets) | 1545 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1547 Where: 1549 o Algorithm: 1 octet value that indicates the algorithm used for 1550 picking the SID 1552 o IPv4 Node Address: 4 octet value which carries the IPv4 address 1553 associated with the node 1555 6.6.1.4. Type 4: SR-MPLS Prefix SID for IPv6 1557 The Segment is SR-MPLS Prefix SID type and is specified as an IPv6 1558 global address. The format of its Segment Descriptor is as follows: 1560 0 1 2 3 1561 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 1562 +-+-+-+-+-+-+-+-+ 1563 | Algorithm | 1564 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1565 | IPv6 Node Global Address (16 octets) | 1566 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1568 Where: 1570 o Algorithm: 1 octet value that indicates the algorithm used for 1571 picking the SID 1573 o IPv6 Node Global Address: 16 octet value which carries the IPv6 1574 global address associated with the node 1576 6.6.1.5. Type 5: SR-MPLS Adjacency SID for IPv4 with Interface ID 1578 The Segment is SR-MPLS Adjacency SID type and is specified as an IPv4 1579 node address along with the local interface ID on that node. The 1580 format of its Segment Descriptor is as follows: 1582 0 1 2 3 1583 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 1584 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1585 | IPv4 Node Address (4 octets) | 1586 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1587 | Local Interface ID (4 octets) | 1588 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1590 Where: 1592 o IPv4 Node Address: 4 octet value which carries the IPv4 address 1593 associated with the node 1595 o Local Interface ID : 4 octet value which carries the local 1596 interface ID of the node identified by the Node Address 1598 6.6.1.6. Type 6: SR-MPLS Adjacency SID for IPv4 with Interface Address 1600 The Segment is SR-MPLS Adjacency SID type and is specified as a pair 1601 of IPv4 local and remote addresses. The format of its Segment 1602 Descriptor is as follows: 1604 0 1 2 3 1605 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 1606 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1607 | IPv4 Local Address (4 octets) | 1608 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1609 | IPv4 Remote Address (4 octets) | 1610 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1612 Where: 1614 o IPv4 Local Address: 4 octet value which carries the local IPv4 1615 address associated with the node 1617 o IPv4 Remote Address: 4 octet value which carries the remote IPv4 1618 address associated with the node's neighbor. This is optional and 1619 MAY be set to 0 when not used (e.g. when identifying point-to- 1620 point links). 1622 6.6.1.7. Type 7: SR-MPLS Adjacency SID for IPv6 with interface ID 1624 The Segment is SR-MPLS Adjacency SID type and is specified as a pair 1625 of IPv6 global address and interface ID for local and remote nodes. 1626 The format of its Segment Descriptor is as follows: 1628 0 1 2 3 1629 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 1630 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1631 | IPv6 Local Node Global Address (16 octets) | 1632 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1633 | Local Node Interface ID (4 octets) | 1634 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1635 | IPv6 Remote Node Global Address (16 octets) | 1636 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1637 | Remote Node Interface ID (4 octets) | 1638 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1640 Where: 1642 o IPv6 Local Node Global Address: 16 octet value which carries the 1643 IPv6 global address associated with the local node 1645 o Local Node Interface ID : 4 octet value which carries the 1646 interface ID of the local node identified by the Local Node 1647 Address 1649 o IPv6 Remote Node Global Address: 16 octet value which carries the 1650 IPv6 global address associated with the remote node. This is 1651 optional and MAY be set to 0 when not used (e.g. when identifying 1652 point-to-point links). 1654 o Remote Node Interface ID : 4 octet value which carries the 1655 interface ID of the remote node identified by the Remote Node 1656 Address. This is optional and MAY be set to 0 when not used (e.g. 1657 when identifying point-to-point links). 1659 6.6.1.8. Type 8: SR-MPLS Adjacency SID for IPv6 with interface address 1661 The Segment is SR-MPLS Adjacency SID type and is specified as a pair 1662 of IPv6 Global addresses for local and remote interface addresses. 1663 The format of its Segment Descriptor is as follows: 1665 0 1 2 3 1666 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 1667 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1668 | Global IPv6 Local Interface Address (16 octets) | 1669 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1670 | Global IPv6 Remote Interface Address (16 octets) | 1671 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1673 Where: 1675 o IPv6 Local Address: 16 octet value which carries the local IPv6 1676 address associated with the node 1678 o IPv6 Remote Address: 16 octet value which carries the remote IPv6 1679 address associated with the node's neighbor 1681 6.6.1.9. Type 9: SRv6 END SID as IPv6 Node Address 1683 The Segment is SRv6 END SID type and is specified as an IPv6 global 1684 address. The format of its Segment Descriptor is as follows: 1686 0 1 2 3 1687 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 1688 +-+-+-+-+-+-+-+-+ 1689 | Algorithm | 1690 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1691 | IPv6 Node Global Address (16 octets) | 1692 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1694 Where: 1696 o Algorithm: 1 octet value that indicates the algorithm used for 1697 picking the SID 1699 o IPv6 Node Global Address: 16 octet value which carries the IPv6 1700 global address associated with the node 1702 6.6.1.10. Type 10: SRv6 END.X SID as interface ID 1704 The Segment is SRv6 END.X SID type and is specified as a pair of IPv6 1705 global address and interface ID for local and remote nodes. The 1706 format of its Segment Descriptor is as follows: 1708 0 1 2 3 1709 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 1710 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1711 | IPv6 Local Node Global Address (16 octets) | 1712 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1713 | Local Node Interface ID (4 octets) | 1714 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1715 | IPv6 Remote Node Global Address (16 octets) | 1716 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1717 | Remote Node Interface ID (4 octets) | 1718 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1720 Where: 1722 o IPv6 Local Node Global Address: 16 octet value which carries the 1723 IPv6 global address associated with the local node 1725 o Local Node Interface ID : 4 octet value which carries the 1726 interface ID of the local node identified by the Local Node 1727 Address 1729 o IPv6 Remote Node Global Address: 16 octet value which carries the 1730 IPv6 global address associated with the remote node. This is 1731 optional and MAY be set to 0 when not used (e.g. when identifying 1732 point-to-point links). 1734 o Remote Node Interface ID : 4 octet value which carries the 1735 interface ID of the remote node identified by the Remote Node 1736 Address. This is optional and MAY be set to 0 when not used (e.g. 1737 when identifying point-to-point links). 1739 6.6.1.11. Type 11: SRv6 END.X SID as interface address 1741 The Segment is SRv6 END.X SID type and is specified as a pair of IPv6 1742 Global addresses for local and remote interface addresses. The 1743 format of its Segment Descriptor is as follows: 1745 0 1 2 3 1746 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 1747 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1748 | Global IPv6 Local Interface Address (16 octets) | 1749 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1750 | Global IPv6 Remote Interface Address (16 octets) | 1751 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1753 Where: 1755 o IPv6 Local Address: 16 octet value which carries the local IPv6 1756 address associated with the node 1758 o IPv6 Remote Address: 16 octet value which carries the remote IPv6 1759 address associated with the node's neighbor 1761 6.7. SR Segment List Metric 1763 The SR Segment List Metric sub-TLV describes the metric used for 1764 computation of the SID-List. It is used to report the type of metric 1765 used in the computation of a dynamic path either on the headend or 1766 when the path computation is delegated to a PCE/controller. When the 1767 path computation is done on the headend, it is also used to report 1768 the calculated metric for the path. 1770 It is a sub-TLV of the SR Segment List TLV and has following format: 1772 0 1 2 3 1773 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 1774 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1775 | Type | Length | 1776 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1777 | Metric Type | Flags | RESERVED | 1778 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1779 | Metric Margin | 1780 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1781 | Metric Bound | 1782 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1783 | Metric Value | 1784 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1786 where: 1788 o Type: 1207 1790 o Length: 16 octets 1792 o Metric Type : 1 octet field which identifies the type of metric 1793 used for path computation. Following metric type codepoints are 1794 defined in this document. 1796 +------------+-----------------------------------------+ 1797 | Code Point | Metric Type | 1798 +------------+-----------------------------------------+ 1799 | 0 | IGP Metric | 1800 | 1 | Min Unidirectional Link Delay [RFC7471] | 1801 | 2 | TE Metric [RFC3630] | 1802 +------------+-----------------------------------------+ 1803 o Flags: 1 octet field that indicates the validity of the metric 1804 fields and their semantics. The following bit positions are 1805 defined and the other bits SHOULD be cleared by originator and 1806 MUST be ignored by receiver. 1808 0 1 2 3 4 5 6 7 1809 +-+-+-+-+-+-+-+-+ 1810 |M|A|B|V| | 1811 +-+-+-+-+-+-+-+-+ 1813 where: 1815 * M-Flag : Indicates that the metric margin allowed for path 1816 computation is specified when set 1818 * A-Flag : Indicates that the metric margin is specified as an 1819 absolute value when set and is expressed as a percentage of the 1820 minimum metric when clear. 1822 * B-Flag : Indicates that the metric bound allowed for the path 1823 is specified when set. 1825 * V-Flag : Indicates that the metric value computed is being 1826 reported when set. 1828 o RESERVED: 2 octets. SHOULD be set to 0 by originator and MUST be 1829 ignored by receiver. 1831 o Metric Margin : 4 octets which indicate the metric margin value 1832 when M-flag is set. The metric margin is specified as either an 1833 absolute value or as a percentage of the minimum computed path 1834 metric based on the A-flag. The metric margin loosens the 1835 criteria for minimum metric path calculation up to the specified 1836 metric to accomodate for other factors such as bandwidth 1837 availability, minimal SID stack depth and maximizing of ECMP for 1838 the SR path computed. 1840 o Metric Bound : 4 octects which indicate the maximum metric value 1841 that is allowed when B-flag is set. If the computed path metric 1842 crosses the specified bound value then the path is considered as 1843 invalid. 1845 o Metric Value : 4 octets which indicate the metric value of the 1846 computed path when V-flag is set. This value is available and 1847 reported when the computation is successful and a valid path is 1848 available. 1850 7. Procedures 1852 The BGP-LS advertisements for the TE Policy NLRI are originated by 1853 the headend node for the TE Policies that are instantiated on its 1854 local node. 1856 For MPLS TE LSPs signaled via RSVP-TE, the NLRI descriptor TLVs as 1857 specified in Section 4.1, Section 4.2, Section 4.3 and Section 4.4 1858 are used. Then the TE LSP state is encoded in the BGP-LS Attribute 1859 field as MPLS-TE Policy State TLV as described in Section 5. The 1860 RSVP-TE objects that reflect the state of the LSP are included as 1861 defined in Section 5.1. When the TE LSP is setup with the help of 1862 PCEP signaling then another MPLS-TE Policy State TLV SHOULD be used 1863 to to encode the related PCEP objects corresponding to the LSP as 1864 defined in Section 5.2. 1866 For SR Policies, the NLRI descriptor TLV as specified in Section 4.5 1867 is used. An SR Policy candidate path (CP) may be instantiated on the 1868 headend node via a local configuration, PCEP or BGP SR Policy 1869 signaling and this is indicated via the SR Protocol Origin. Then the 1870 SR Policy Candidate Path's attribute and state is encoded in the BGP- 1871 LS Attribute field as SR Policy State TLVs and sub-TLVs as described 1872 in Section 6. The SR Candidate Path State TLV as defined in 1873 Section 6.2 is included to report the state of the CP. The SR BSID 1874 TLV as defined in Section 6.1 is included to report the BSID of the 1875 CP when one is either provisioned or allocated by the headend. The 1876 constraints for the SR Policy Candidate Path are reported using the 1877 SR Candidate Path Constraints TLV as described in Section 6.4.The SR 1878 Segment List TLV is included for each of the SID-List(s) associated 1879 with the CP. Each SR Segment List TLV in turn includes SR Segment 1880 sub-TLV(s) to report the segment(s) and their status. The SR Segment 1881 List Metric sub-TLV is used to report the metric values and 1882 constraints for the specific SID List. 1884 When the SR Policy CP is setup with the help of PCEP signaling then 1885 another MPLS-TE Policy State TLV MAY be used to to encode the related 1886 PCEP objects corresponding to the LSP as defined in Section 5.2 1887 specifically to report information and status that is not covered by 1888 the defined TLVs under Section 6. In the event of a conflict of 1889 information, the receiver MUST prefer the information originated via 1890 TLVs defined in Section 6 over the PCEP objects reported via the TE 1891 Policy State TLV. 1893 8. Manageability Considerations 1895 The Existing BGP operational and management procedures apply to this 1896 document. No new procedures are defined in this document. The 1897 considerations as specified in [RFC7752] apply to this document. 1899 In general, it is assumed that the TE Policy head-end nodes are 1900 responsible for the distribution of TE Policy state information, 1901 while other nodes, e.g. the nodes in the path of a policy, MAY report 1902 the TE Policy information (if available) when needed. For example, 1903 the border routers in the inter-domain case will also distribute LSP 1904 state information since the ingress node may not have the complete 1905 information for the end-to-end path. 1907 9. IANA Considerations 1909 This document requires new IANA assigned codepoints. 1911 9.1. BGP-LS NLRI-Types 1913 IANA maintains a registry called "Border Gateway Protocol - Link 1914 State (BGP-LS) Parameters" with a sub-registry called "BGP-LS NLRI- 1915 Types". 1917 The following codepoints have been assigned by early allocation 1918 process by IANA: 1920 +------+----------------------------+---------------+ 1921 | Type | NLRI Type | Reference | 1922 +------+----------------------------+---------------+ 1923 | 5 | TE Policy NLRI type | this document | 1924 +------+----------------------------+---------------+ 1926 9.2. BGP-LS Protocol-IDs 1928 IANA maintains a registry called "Border Gateway Protocol - Link 1929 State (BGP-LS) Parameters" with a sub-registry called "BGP-LS 1930 Protocol-IDs". 1932 The following Protocol-ID codepoints have been assigned by early 1933 allocation process by IANA: 1935 +-------------+----------------------------------+---------------+ 1936 | Protocol-ID | NLRI information source protocol | Reference | 1937 +-------------+----------------------------------+---------------+ 1938 | 8 | RSVP-TE | this document | 1939 | 9 | Segment Routing | this document | 1940 +-------------+----------------------------------+---------------+ 1942 9.3. BGP-LS TLVs 1944 IANA maintains a registry called "Border Gateway Protocol - Link 1945 State (BGP-LS) Parameters" with a sub-registry called "Node Anchor, 1946 Link Descriptor and Link Attribute TLVs". 1948 The following TLV codepoints have been assigned by early allocation 1949 process by IANA: 1951 +----------+----------------------------------------+---------------+ 1952 | TLV Code | Description | Value defined | 1953 | Point | | in | 1954 +----------+----------------------------------------+---------------+ 1955 | 550 | Tunnel ID TLV | this document | 1956 | 551 | LSP ID TLV | this document | 1957 | 552 | IPv4/6 Tunnel Head-end address TLV | this document | 1958 | 553 | IPv4/6 Tunnel Tail-end address TLV | this document | 1959 | 554 | SR Policy CP Descriptor TLV | this document | 1960 | 555 | MPLS Local Cross Connect TLV | this document | 1961 | 556 | MPLS Cross Connect Interface TLV | this document | 1962 | 557 | MPLS Cross Connect FEC TLV | this document | 1963 | 1200 | MPLS-TE Policy State TLV | this document | 1964 | 1201 | SR BSID TLV | this document | 1965 | 1202 | SR CP State TLV | this document | 1966 | 1203 | SR CP Name TLV | this document | 1967 | 1204 | SR CP Constraints TLV | this document | 1968 | 1205 | SR Segment List TLV | this document | 1969 | 1206 | SR Segment sub-TLV | this document | 1970 | 1207 | SR Segment List Metric sub-TLV | this document | 1971 | 1208 | SR Affinity Constraint sub-TLV | this document | 1972 | 1209 | SR SRLG Constraint sub-TLV | this document | 1973 | 1210 | SR Bandwidth Constraint sub-TLV | this document | 1974 | 1211 | SR Disjoint Group Constraint sub-TLV | this document | 1975 +----------+----------------------------------------+---------------+ 1977 9.4. BGP-LS SR Policy Protocol Origin 1979 This document requests IANA to maintain a new sub-registry under 1980 "Border Gateway Protocol - Link State (BGP-LS) Parameters". The new 1981 registry is called "SR Policy Protocol Origin" and contains the 1982 codepoints allocated to the "Protocol Origin" field defined in 1983 Section 4.5. The registry contains the following codepoints, with 1984 initial values, to be assigned by IANA: 1986 +------------+---------------------------------------------------------+ 1987 | Code Point | Protocol Origin | 1988 +------------+---------------------------------------------------------+ 1989 | 1 | PCEP | 1990 | 2 | BGP SR Policy | 1991 | 3 | Local (via CLI, Yang model through NETCONF, gRPC, etc.) | 1992 +------------+---------------------------------------------------------+ 1993 9.5. BGP-LS TE State Object Origin 1995 This document requests IANA to maintain a new sub-registry under 1996 "Border Gateway Protocol - Link State (BGP-LS) Parameters". The new 1997 registry is called "TE State Path Origin" and contains the codepoints 1998 allocated to the "Object Origin" field defined in Section 5. The 1999 registry contains the following codepoints, with initial values, to 2000 be assigned by IANA: 2002 +----------+------------------+ 2003 | Code | Object | 2004 | Point | Origin | 2005 +----------+------------------+ 2006 | 1 | RSVP-TE | 2007 | 2 | PCEP | 2008 | 3 | Local/Static | 2009 +----------+------------------+ 2011 9.6. BGP-LS TE State Address Family 2013 This document requests IANA to maintain a new sub-registry under 2014 "Border Gateway Protocol - Link State (BGP-LS) Parameters". The new 2015 registry is called "TE State Address Family" and contains the 2016 codepoints allocated to the "Address Family" field defined in 2017 Section 5. The registry contains the following codepoints, with 2018 initial values, to be assigned by IANA: 2020 +----------+------------------+ 2021 | Code | Address | 2022 | Point | Family | 2023 +----------+------------------+ 2024 | 1 | MPLS-IPv4 | 2025 | 2 | MPLS-IPv6 | 2026 +----------+------------------+ 2028 9.7. BGP-LS SR Segment Descriptors 2030 This document requests IANA to maintain a new sub-registry under 2031 "Border Gateway Protocol - Link State (BGP-LS) Parameters". The new 2032 registry is called "SR Segment Descriptor Types" and contains the 2033 codepoints allocated to the "Segment Type" field defined in 2034 Section 6.6 and described in Section 6.6.1. The registry contains 2035 the following codepoints, with initial values, to be assigned by 2036 IANA: 2038 +-------+--------------------------------------------------------------+ 2039 | Code | Segment Description | 2040 | Point | | 2041 +-------+--------------------------------------------------------------+ 2042 | 0 | Invalid | 2043 | 1 | SR-MPLS Label | 2044 | 2 | SRv6 SID as IPv6 address | 2045 | 3 | SR-MPLS Prefix SID as IPv4 Node Address | 2046 | 4 | SR-MPLS Prefix SID as IPv6 Node Global Address | 2047 | 5 | SR-MPLS Adjacency SID as IPv4 Node Address & Local | 2048 | | Interface ID | 2049 | 6 | SR-MPLS Adjacency SID as IPv4 Local & Remote Interface | 2050 | | Addresses | 2051 | 7 | SR-MPLS Adjacency SID as pair of IPv6 Global Address & | 2052 | | Interface ID for Local & Remote nodes | 2053 | 8 | SR-MPLS Adjacency SID as pair of IPv6 Global Addresses for | 2054 | | the Local & Remote Interface | 2055 | 9 | SRv6 END SID as IPv6 Node Global Address | 2056 | 10 | SRv6 END.X SID as pair of IPv6 Global Address & Interface ID | 2057 | | for Local & Remote nodes | 2058 | 11 | SRv6 END.X SID as pair of IPv6 Global Addresses for the | 2059 | | Local & Remote Interface | 2060 +-------+--------------------------------------------------------------+ 2062 9.8. BGP-LS Metric Type 2064 This document requests IANA to maintain a new sub-registry under 2065 "Border Gateway Protocol - Link State (BGP-LS) Parameters". The new 2066 registry is called "Metric Type" and contains the codepoints 2067 allocated to the "metric type" field defined in Section 6.7. The 2068 registry contains the following codepoints, with initial values, to 2069 be assigned by IANA: 2071 +------------+-----------------------------------------+ 2072 | Code Point | Metric Type | 2073 +------------+-----------------------------------------+ 2074 | 0 | IGP Metric | 2075 | 1 | Min Unidirectional Link Delay [RFC7471] | 2076 | 2 | TE Metric [RFC3630] | 2077 +------------+-----------------------------------------+ 2079 10. Security Considerations 2081 Procedures and protocol extensions defined in this document do not 2082 affect the BGP security model. See [RFC6952] for details. 2084 11. Contributors 2086 The following people have substantially contributed to the editing of 2087 this document: 2089 Clarence Filsfils 2090 Cisco Systems 2091 Email: cfilsfil@cisco.com 2093 12. Acknowledgements 2095 The authors would like to thank Dhruv Dhody, Mohammed Abdul Aziz 2096 Khalid, Lou Berger, Acee Lindem, Siva Sivabalan, Arjun Sreekantiah, 2097 and Dhanendra Jain for their review and valuable comments. 2099 13. References 2101 13.1. Normative References 2103 [I-D.ietf-idr-bgpls-segment-routing-epe] 2104 Previdi, S., Talaulikar, K., Filsfils, C., Patel, K., Ray, 2105 S., and J. Dong, "BGP-LS extensions for Segment Routing 2106 BGP Egress Peer Engineering", draft-ietf-idr-bgpls- 2107 segment-routing-epe-19 (work in progress), May 2019. 2109 [I-D.ietf-spring-segment-routing-policy] 2110 Filsfils, C., Sivabalan, S., daniel.voyer@bell.ca, d., 2111 bogdanov@google.com, b., and P. Mattes, "Segment Routing 2112 Policy Architecture", draft-ietf-spring-segment-routing- 2113 policy-03 (work in progress), May 2019. 2115 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 2116 Requirement Levels", BCP 14, RFC 2119, 2117 DOI 10.17487/RFC2119, March 1997, 2118 . 2120 [RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S. 2121 Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 2122 Functional Specification", RFC 2205, DOI 10.17487/RFC2205, 2123 September 1997, . 2125 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 2126 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 2127 Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, 2128 . 2130 [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label 2131 Switching (GMPLS) Signaling Resource ReserVation Protocol- 2132 Traffic Engineering (RSVP-TE) Extensions", RFC 3473, 2133 DOI 10.17487/RFC3473, January 2003, 2134 . 2136 [RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast 2137 Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090, 2138 DOI 10.17487/RFC4090, May 2005, 2139 . 2141 [RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, 2142 "Multiprotocol Extensions for BGP-4", RFC 4760, 2143 DOI 10.17487/RFC4760, January 2007, 2144 . 2146 [RFC4872] Lang, J., Ed., Rekhter, Y., Ed., and D. Papadimitriou, 2147 Ed., "RSVP-TE Extensions in Support of End-to-End 2148 Generalized Multi-Protocol Label Switching (GMPLS) 2149 Recovery", RFC 4872, DOI 10.17487/RFC4872, May 2007, 2150 . 2152 [RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel, 2153 "GMPLS Segment Recovery", RFC 4873, DOI 10.17487/RFC4873, 2154 May 2007, . 2156 [RFC4874] Lee, CY., Farrel, A., and S. De Cnodder, "Exclude Routes - 2157 Extension to Resource ReserVation Protocol-Traffic 2158 Engineering (RSVP-TE)", RFC 4874, DOI 10.17487/RFC4874, 2159 April 2007, . 2161 [RFC5420] Farrel, A., Ed., Papadimitriou, D., Vasseur, JP., and A. 2162 Ayyangarps, "Encoding of Attributes for MPLS LSP 2163 Establishment Using Resource Reservation Protocol Traffic 2164 Engineering (RSVP-TE)", RFC 5420, DOI 10.17487/RFC5420, 2165 February 2009, . 2167 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 2168 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 2169 DOI 10.17487/RFC5440, March 2009, 2170 . 2172 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 2173 S. Ray, "North-Bound Distribution of Link-State and 2174 Traffic Engineering (TE) Information Using BGP", RFC 7752, 2175 DOI 10.17487/RFC7752, March 2016, 2176 . 2178 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2179 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2180 May 2017, . 2182 13.2. Informative References 2184 [RFC2702] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M., and J. 2185 McManus, "Requirements for Traffic Engineering Over MPLS", 2186 RFC 2702, DOI 10.17487/RFC2702, September 1999, 2187 . 2189 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 2190 (TE) Extensions to OSPF Version 2", RFC 3630, 2191 DOI 10.17487/RFC3630, September 2003, 2192 . 2194 [RFC4202] Kompella, K., Ed. and Y. Rekhter, Ed., "Routing Extensions 2195 in Support of Generalized Multi-Protocol Label Switching 2196 (GMPLS)", RFC 4202, DOI 10.17487/RFC4202, October 2005, 2197 . 2199 [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation 2200 Element (PCE)-Based Architecture", RFC 4655, 2201 DOI 10.17487/RFC4655, August 2006, 2202 . 2204 [RFC5065] Traina, P., McPherson, D., and J. Scudder, "Autonomous 2205 System Confederations for BGP", RFC 5065, 2206 DOI 10.17487/RFC5065, August 2007, 2207 . 2209 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 2210 BGP, LDP, PCEP, and MSDP Issues According to the Keying 2211 and Authentication for Routing Protocols (KARP) Design 2212 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 2213 . 2215 [RFC7308] Osborne, E., "Extended Administrative Groups in MPLS 2216 Traffic Engineering (MPLS-TE)", RFC 7308, 2217 DOI 10.17487/RFC7308, July 2014, 2218 . 2220 [RFC7471] Giacalone, S., Ward, D., Drake, J., Atlas, A., and S. 2221 Previdi, "OSPF Traffic Engineering (TE) Metric 2222 Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015, 2223 . 2225 [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path 2226 Computation Element Communication Protocol (PCEP) 2227 Extensions for Stateful PCE", RFC 8231, 2228 DOI 10.17487/RFC8231, September 2017, 2229 . 2231 Authors' Addresses 2233 Stefano Previdi 2235 Email: stefano@previdi.net 2237 Ketan Talaulikar (editor) 2238 Cisco Systems, Inc. 2239 India 2241 Email: ketant@cisco.com 2243 Jie Dong (editor) 2244 Huawei Technologies 2245 Huawei Campus, No. 156 Beiqing Rd. 2246 Beijing 100095 2247 China 2249 Email: jie.dong@huawei.com 2251 Mach(Guoyi) Chen 2252 Huawei Technologies 2253 Huawei Campus, No. 156 Beiqing Rd. 2254 Beijing 100095 2255 China 2257 Email: mach.chen@huawei.com 2259 Hannes Gredler 2260 RtBrick Inc. 2262 Email: hannes@rtbrick.com 2264 Jeff Tantsura 2265 Apstra 2267 Email: jefftant.ietf@gmail.com