idnits 2.17.1 draft-ietf-pce-association-bidir-04.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (September 11, 2019) is 1682 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) No issues found here. Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 PCE Working Group R. Gandhi, Ed. 3 Internet-Draft Cisco Systems, Inc. 4 Intended status: Standards Track C. Barth 5 Expires: March 14, 2020 Juniper Networks 6 B. Wen 7 Comcast 8 September 11, 2019 10 PCEP Extensions for 11 Associated Bidirectional Label Switched Paths (LSPs) 12 draft-ietf-pce-association-bidir-04 14 Abstract 16 The Path Computation Element Communication Protocol (PCEP) provides 17 mechanisms for Path Computation Elements (PCEs) to perform path 18 computations in response to Path Computation Clients (PCCs) requests. 19 The Stateful PCE extensions allow stateful control of Multiprotocol 20 Label Switching (MPLS) Traffic Engineering (TE) Label Switched Paths 21 (LSPs) using PCEP. 23 This document defines PCEP extensions for grouping two reverse 24 unidirectional MPLS TE LSPs into an Associated Bidirectional LSP when 25 using a Stateful PCE for both PCE-Initiated and PCC-Initiated LSPs as 26 well as when using a Stateless PCE. The procedures defined are 27 applicable to the LSPs using Resource Reservation Protocol (RSVP) for 28 signaling. 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at http://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 Copyright Notice 47 Copyright (c) 2019 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents 52 (http://trustee.ietf.org/license-info) in effect on the date of 53 publication of this document. Please review these documents 54 carefully, as they describe your rights and restrictions with respect 55 to this document. Code Components extracted from this document must 56 include Simplified BSD License text as described in Section 4.e of 57 the Trust Legal Provisions and are provided without warranty as 58 described in the Simplified BSD License. 60 Table of Contents 62 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 63 2. Conventions Used in This Document . . . . . . . . . . . . . . 4 64 2.1. Key Word Definitions . . . . . . . . . . . . . . . . . . . 4 65 2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 66 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 67 3.1. Single-sided Initiation . . . . . . . . . . . . . . . . . 5 68 3.2. Double-sided Initiation . . . . . . . . . . . . . . . . . 6 69 3.3. Co-routed Associated Bidirectional LSP . . . . . . . . . . 7 70 4. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 8 71 4.1. Association Object . . . . . . . . . . . . . . . . . . . . 8 72 4.2. Bidirectional LSP Association Group TLV . . . . . . . . . 9 73 5. PCEP Procedure . . . . . . . . . . . . . . . . . . . . . . . . 10 74 5.1. PCE Initiated LSPs . . . . . . . . . . . . . . . . . . . . 10 75 5.2. PCC Initiated LSPs . . . . . . . . . . . . . . . . . . . . 10 76 5.3. Stateless PCE . . . . . . . . . . . . . . . . . . . . . . 11 77 5.4. Bidirectional (B) Flag . . . . . . . . . . . . . . . . . . 11 78 5.5. PLSP-ID Usage . . . . . . . . . . . . . . . . . . . . . . 11 79 5.6. State Synchronization . . . . . . . . . . . . . . . . . . 12 80 5.7. Error Handling . . . . . . . . . . . . . . . . . . . . . . 12 81 6. Implementation Status . . . . . . . . . . . . . . . . . . . . 13 82 6.1. Implementation . . . . . . . . . . . . . . . . . . . . . . 13 83 7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 84 8. Manageability Considerations . . . . . . . . . . . . . . . . . 14 85 8.1. Control of Function and Policy . . . . . . . . . . . . . . 14 86 8.2. Information and Data Models . . . . . . . . . . . . . . . 14 87 8.3. Liveness Detection and Monitoring . . . . . . . . . . . . 14 88 8.4. Verify Correct Operations . . . . . . . . . . . . . . . . 14 89 8.5. Requirements On Other Protocols . . . . . . . . . . . . . 14 90 8.6. Impact On Network Operations . . . . . . . . . . . . . . . 14 91 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 92 9.1. Association Types . . . . . . . . . . . . . . . . . . . . 14 93 9.2. Bidirectional LSP Association Group TLV . . . . . . . . . 15 94 9.2.1. Flag Fields in Bidirectional LSP Association Group 95 TLV . . . . . . . . . . . . . . . . . . . . . . . . . 15 96 9.3. PCEP Errors . . . . . . . . . . . . . . . . . . . . . . . 15 97 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 17 98 10.1. Normative References . . . . . . . . . . . . . . . . . . 17 99 10.2. Informative References . . . . . . . . . . . . . . . . . 18 100 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 19 101 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 103 1. Introduction 105 [RFC5440] describes the Path Computation Element Protocol (PCEP) as a 106 communication mechanism between a Path Computation Client (PCC) and a 107 Path Control Element (PCE), or between PCE and PCC, that enables 108 computation of Multiprotocol Label Switching (MPLS) Traffic 109 Engineering (TE) Label Switched Paths (LSPs). 111 [RFC8231] specifies extensions to PCEP to enable stateful control of 112 MPLS TE LSPs. It describes two modes of operation - Passive Stateful 113 PCE and Active Stateful PCE. In [RFC8231], the focus is on Active 114 Stateful PCE where LSPs are provisioned on the PCC and control over 115 them is delegated to a PCE. Further, [RFC8281] describes the setup, 116 maintenance and teardown of PCE-Initiated LSPs for the Stateful PCE 117 model. 119 [I-D.ietf-pce-association] introduces a generic mechanism to create a 120 grouping of LSPs which can then be used to define associations 121 between a set of LSPs and/or a set of attributes, for example primary 122 and secondary LSP associations, and is equally applicable to the 123 active and passive modes of a Stateful PCE [RFC8231] or a stateless 124 PCE [RFC5440]. 126 The MPLS Transport Profile (MPLS-TP) requirements document [RFC5654] 127 specifies that MPLS-TP MUST support associated bidirectional 128 point-to-point LSPs. [RFC7551] defines RSVP signaling extensions for 129 binding two reverse unidirectional LSPs [RFC3209] into an associated 130 bidirectional LSP. The fast reroute (FRR) procedures for associated 131 bidirectional LSPs are described in [RFC8537]. 133 This document defines PCEP extensions for grouping two reverse 134 unidirectional MPLS-TE LSPs into an Associated Bidirectional LSP for 135 both single-sided and double-sided initiation cases when using a 136 Stateful (both active and passive modes) or Stateless PCE. The 137 procedures defined are applicable to the LSPs using Resource 138 Reservation Protocol (RSVP) for signaling [RFC3209]. The PCEP 139 extensions cover the following cases: 141 o A PCC initiates the forward and/ or reverse LSP of a single-sided 142 or double-sided bidirectional LSP and retains the control of the 143 LSP. The PCC computes the path itself or makes a request for path 144 computation to a PCE. After the path setup, it reports the 145 information and state of the path to the PCE. This includes the 146 association group identifying the bidirectional LSP. This is the 147 Passive Stateful mode defined in [RFC8051]. 149 o A PCC initiates the forward and/ or reverse LSP of a single-sided 150 or double-sided bidirectional LSP and delegates the control of the 151 LSP to a Stateful PCE. During delegation the association group 152 identifying the bidirectional LSP is included. The PCE computes 153 the path of the LSP and updates the PCC with the information about 154 the path as long as it controls the LSP. This is the Active 155 Stateful mode defined in [RFC8051]. 157 o A PCE initiates the forward and/ or reverse LSP of a single-sided 158 or double-sided bidirectional LSP on a PCC and retains the control 159 of the LSP. The PCE is responsible for computing the path of the 160 LSP and updating the PCC with the information about the path as 161 well as the association group identifying the bidirectional LSP. 162 This is the PCE-Initiated mode defined in [RFC8281]. 164 o A PCC requests co-routed or non co-routed paths for forward and 165 reverse LSPs of a bidirectional LSP from a Stateless PCE 166 [RFC5440]. 168 2. Conventions Used in This Document 170 2.1. Key Word Definitions 172 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 173 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 174 "OPTIONAL" in this document are to be interpreted as described in BCP 175 14 [RFC2119] [RFC8174] when, and only when, they appear in all 176 capitals, as shown here. 178 2.2. Terminology 180 The reader is assumed to be familiar with the terminology defined in 181 [RFC5440], [RFC7551], [RFC8231], and [I-D.ietf-pce-association]. 183 3. Overview 185 As shown in Figure 1, two reverse unidirectional LSPs can be grouped 186 to form an associated bidirectional LSP. There are two methods of 187 initiating the bidirectional LSP association, single-sided and 188 double-sided, as defined in [RFC7551] and described in the following 189 sections. 191 LSP1 --> LSP1 --> LSP1 --> 192 +-----+ +-----+ +-----+ +-----+ 193 | A +-----------+ B +-----------+ C +-----------+ D | 194 +-----+ +--+--+ +--+--+ +-----+ 195 <-- LSP2 | | <-- LSP2 196 | | 197 | | 198 +--+--+ +--+--+ 199 | E +-----------+ F | 200 +-----+ +-----+ 201 <-- LSP2 203 Figure 1: Example of Associated Bidirectional LSP 205 3.1. Single-sided Initiation 207 As specified in [RFC7551], in the single-sided case, the 208 bidirectional tunnel is provisioned only on one endpoint node (PCC) 209 of the tunnel. Both forward and reverse LSPs of this tunnel are 210 initiated with the Association Type set to "Single-sided 211 Bidirectional LSP Association" on the originating endpoint node. The 212 forward and reverse LSPs are identified in the Bidirectional LSP 213 Association Group TLV of their PCEP Association Objects. 215 The originating endpoint node signals the properties for the revere 216 LSP in the RSVP REVERSE_LSP Object [RFC7551] of the forward LSP Path 217 message. The remote endpoint then creates the corresponding reverse 218 tunnel and signals the reverse LSP in response to the received RSVP 219 Path message. Similarly, the remote endpoint node deletes the 220 reverse LSP when it receives the RSVP Path delete message [RFC3209] 221 for the forward LSP. 223 The originating endpoint (PCC) node may report/ delegate the forward 224 and reverse direction LSPs to a PCE. The remote endpoint (PCC) node 225 may report its forward direction LSP to a PCE. 227 +-----+ 228 | PCE | 229 +-----+ 230 Initiates: | ^ Reports: 231 Tunnel 1 (F) | \ Tunnel 2 (F) 232 (LSP1 (F), LSP2 (R)) | \ (LSP2 (F)) 233 Association #1 v \ Association #1 234 +-----+ +-----+ 235 | A | | D | 236 +-----+ +-----+ 238 Figure 2A: Example of PCE-Initiated Single-sided Bidirectional LSP 240 +-----+ 241 | PCE | 242 +-----+ 243 Reports/Delegates: ^ ^ Reports: 244 Tunnel 1 (F) | \ Tunnel 2 (F) 245 (LSP1 (F), LSP2 (R)) | \ (LSP2 (F)) 246 Association #2 | \ Association #2 247 +-----+ +-----+ 248 | A | | D | 249 +-----+ +-----+ 251 Figure 2B: Example of PCC-Initiated Single-sided Bidirectional LSP 253 As shown in Figures 2A and 2B, the forward tunnel and both forward 254 LSP1 and reverse LSP2 are initiated on the originating endpoint node 255 A, either by the PCE or the originating PCC, respectively. The 256 originating endpoint node A signals the properties of reverse LSP2 in 257 the RSVP REVERSE_LSP Object in the Path message of the forward LSP1. 258 The creation of reverse tunnel and reverse LSP2 on the remote 259 endpoint node D is triggered by the RSVP signaled forward LSP1. 261 As specified in [RFC8537], for fast reroute bypass tunnel assignment, 262 the LSP starting from the originating node is identified as the 263 forward LSP of the single-sided initiated bidirectional LSP. 265 3.2. Double-sided Initiation 267 As specified in [RFC7551], in the double-sided case, the 268 bidirectional tunnel is provisioned on both endpoint nodes (PCCs) of 269 the tunnel. The forward and reverse LSPs of this tunnel are 270 initiated with the Association Type set to "Double-sided 271 Bidirectional LSP Association" on both endpoint nodes. The forward 272 and reverse LSPs are identified in the Bidirectional LSP Association 273 Group TLV of their Association Objects. 275 The endpoint (PCC) nodes may report/ delegate the forward and reverse 276 direction LSPs to a PCE. 278 +-----+ 279 | PCE | 280 +-----+ 281 Initiates: | \ Initiates: 282 Tunnel 1 (F) | \ Tunnel 2 (F) 283 (LSP1 (F)) | \ (LSP2 (F)) 284 Association #3 v v Association #3 285 +-----+ +-----+ 286 | A | | D | 287 +-----+ +-----+ 289 Figure 3A: Example of PCE-Initiated Double-sided Bidirectional LSP 291 +-----+ 292 | PCE | 293 +-----+ 294 Reports/Delegates: ^ ^ Reports/Delegates: 295 Tunnel 1 (F) | \ Tunnel 2 (F) 296 (LSP1 (F)) | \ (LSP2 (F)) 297 Association #4 | \ Association #4 298 +-----+ +-----+ 299 | A | | D | 300 +-----+ +-----+ 302 Figure 3B: Example of PCC-Initiated Double-sided Bidirectional LSP 304 As shown in Figures 3A and 3B, the forward tunnel and forward LSP1 305 are initiated on the endpoint node A and the reverse tunnel and 306 reverse LSP2 are initiated on the endpoint node D, either by the PCE 307 or the PCCs, respectively. 309 As specified in [RFC8537], for fast reroute bypass tunnel assignment, 310 the LSP with the higher Source Address [RFC3209] is identified as the 311 forward LSP of the double-sided initiated bidirectional LSP. 313 3.3. Co-routed Associated Bidirectional LSP 315 In both single-sided and double-sided initiation cases, forward and 316 reverse LSPs may be co-routed as shown in Figure 4, where both 317 forward and reverse LSPs of a bidirectional LSP follow the same 318 congruent path in the forward and reverse directions, respectively. 320 LSP3 --> LSP3 --> LSP3 --> 321 +-----+ +-----+ +-----+ +-----+ 322 | A +-----------+ B +-----------+ C +-----------+ D | 323 +-----+ +-----+ +-----+ +-----+ 324 <-- LSP4 <-- LSP4 <-- LSP4 326 Figure 4: Example of Co-routed Associated Bidirectional LSP 328 4. Protocol Extensions 330 4.1. Association Object 332 As per [I-D.ietf-pce-association], LSPs are associated by adding them 333 to a common association group. This document defines two new 334 Bidirectional LSP Association Groups to be used by the associated 335 bidirectional LSPs. A member of the Bidirectional LSP Association 336 Group can take the role of a forward or reverse LSP and follows the 337 following rules: 339 o An LSP (forward or reverse) can not be part of more than one 340 Bidirectional LSP Association Group. More than one forward LSP 341 and/ or reverse LSP can be part of a Bidirectional LSP Association 342 Group. 344 o The Tunnel (as defined in [RFC3209]) of forward and reverse LSPs 345 of the single-sided bidirectional LSP association on the 346 originating node MUST be the same. 348 This document defines two new Association Types for the Association 349 Object as follows: 351 o Association Type (TBD1) = Single-sided Bidirectional LSP 352 Association Group 354 o Association Type (TBD2) = Double-sided Bidirectional LSP 355 Association Group 357 These Association Types are operator-configured associations in 358 nature and statically created by the operator on the PCEP peers. The 359 LSP belonging to these associations is conveyed via PCEP messages to 360 the PCEP peer. Operator-configured Association Range TLV 361 [I-D.ietf-pce-association] MUST NOT be sent for these Association 362 Types, and MUST be ignored, so that the entire range of association 363 ID can be used for them. 365 The Association ID, Association Source, optional Global Association 366 Source and optional Extended Association ID in the Bidirectional LSP 367 Association Group Object are initialized using the procedures defined 368 in [I-D.ietf-pce-association] and [RFC7551]. 370 4.2. Bidirectional LSP Association Group TLV 372 The Bidirectional LSP Association Group TLV is defined for use with 373 the Single-sided and Double-sided Bidirectional LSP Association Group 374 Object Types. 376 o The Bidirectional LSP Association Group TLV follows the PCEP TLV 377 format from [RFC5440]. 379 o The Type (16 bits) of the TLV is TBD3, to be assigned by IANA. 381 o The Length is 4 Bytes. 383 o The value comprises of a single field, the Bidirectional LSP 384 Association Flags (32 bits), where each bit represents a flag 385 option. 387 o If the Bidirectional LSP Association Group TLV is missing, it 388 means the LSP is the forward LSP and it is not co-routed LSP. 390 o For co-routed LSPs, this TLV MUST be present. 392 o For reverse LSPs, this TLV MUST be present. 394 o The Bidirectional LSP Association Group TLV MUST NOT be present 395 more than once. If it appears more than once, only the first 396 occurrence is processed and any others MUST be ignored. 398 The format of the Bidirectional LSP Association Group TLV is shown in 399 Figure 5: 401 0 1 2 3 402 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 1 403 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 404 | Type = TBD3 | Length | 405 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 406 | Reserved |C|R|F| 407 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 409 Figure 5: Bidirectional LSP Association Group TLV format 411 Bidirectional LSP Association Flags are defined as following. 413 F (Forward LSP, 1 bit) - Indicates whether the LSP associated is the 414 forward LSP of the bidirectional LSP. If this flag is set, the LSP 415 is a forward LSP. 417 R (Reverse LSP, 1 bit) - Indicates whether the LSP associated is the 418 reverse LSP of the bidirectional LSP. If this flag is set, the LSP 419 is a reverse LSP. 421 C (Co-routed LSP, 1 bit) - Indicates whether the bidirectional LSP is 422 co-routed. This flag MUST be set for both the forward and reverse 423 LSPs of a co-routed bidirectional LSP. 425 The C flag is used by the PCE (for both Stateful and Stateless) to 426 compute bidirectional paths of the forward and reverse LSPs of a 427 co-routed bidirectional LSP. 429 The Reserved flags MUST be set to 0 when sent and MUST be ignored 430 when received. 432 5. PCEP Procedure 434 5.1. PCE Initiated LSPs 436 As specified in [I-D.ietf-pce-association], the Bidirectional LSP 437 Association Groups can be created by a Stateful PCE. 439 o Stateful PCE can create and update the forward and reverse LSPs 440 independently for both single-sided and double-sided bidirectional 441 LSP association groups. 443 o Stateful PCE can establish and remove the association relationship 444 on a per LSP basis. 446 o Stateful PCE can create and update the LSP and the association on 447 a PCC via PCInitiate and PCUpd messages, respectively, using the 448 procedures described in [I-D.ietf-pce-association]. 450 5.2. PCC Initiated LSPs 452 As specified in [I-D.ietf-pce-association], Bidirectional LSP 453 Association Groups can also be created by a PCC. 455 o PCC can create and update the forward and reverse LSPs 456 independently for both single-sided and double-sided bidirectional 457 LSP association groups. 459 o PCC can establish and remove the association relationship on a per 460 LSP basis. 462 o PCC MUST report the change in the association group of an LSP to 463 PCE(s) via PCRpt message. 465 o PCC can report the forward and reverse LSPs independently to 466 PCE(s) via PCRpt message. 468 o PCC can delegate the forward and reverse LSPs independently to a 469 Stateful PCE, where PCE would control the LSPs. For single-sided 470 case, originating (PCC) node can delegate both forward and reverse 471 LSPs of a tunnel together to a Stateful PCE in order to avoid any 472 race condition. 474 o Stateful PCE can update the LSPs in the bidirectional LSP 475 association group via PCUpd message, using the procedures 476 described in [I-D.ietf-pce-association]. 478 5.3. Stateless PCE 480 For a stateless PCE, it might be useful to associate a path 481 computation request to an association group, thus enabling it to 482 associate a common set of configuration parameters or behaviors with 483 the request. A PCC can request co-routed or non co-routed forward 484 and reverse direction paths from a stateless PCE for a bidirectional 485 LSP association group. 487 5.4. Bidirectional (B) Flag 489 As defined in [RFC5440], the Bidirectional (B) flag in the Request 490 Parameters (RP) object is set when the PCC specifies that the path 491 computation request is for a bidirectional TE LSP with the same TE 492 requirements (e.g. latency) in each direction. For an associated 493 bidirectional LSP, the B-flag MAY be set when the PCC makes the path 494 computation request for the same TE requirements in the forward and 495 reverse directions. When a stateful PCE initiates or updates the 496 bidirectional LSPs, the B-flag in Stateful PCE Request Parameters 497 (SRP) object [RFC8231] MAY also be set. 499 5.5. PLSP-ID Usage 501 As defined in [RFC8231], a PCEP-specific LSP Identifier (PLSP-ID) is 502 created by a PCC to uniquely identify each LSP and is constant for 503 the lifetime of a PCEP session. 505 In case of single-sided bidirectional LSP association, the reverse 506 LSP of a bidirectional LSP on the originating node is identified 507 using 2 different PLSP-IDs based on the PCEP session on the ingress 508 or egress nodes for the LSP. In other words, the reverse LSP on the 509 originating node will have a PLSP-ID A at the ingress node while it 510 will have a PLSP-ID B at the egress node. This is not the case for 511 the forward LSP of the single-sided bidirectional LSP on the 512 originating node and there is no change in the PLSP-ID allocation for 513 it. 515 In case of double-sided bidirectional LSP association, there is no 516 change in the PLSP-ID allocation. 518 For an Associated Bidirectional LSP, LSP-IDENTIFIERS TLV [RFC8231] 519 MUST be included in all forward and reverse LSPs. 521 5.6. State Synchronization 523 During state synchronization, a PCC MUST report all the existing 524 bidirectional LSP association groups to the Stateful PCE as per 525 [I-D.ietf-pce-association]. After the state synchronization, the PCE 526 MUST remove all stale bidirectional LSP associations. 528 5.7. Error Handling 530 An LSP (forward or reverse) can not be part of more than one 531 Bidirectional LSP Association Group. If a PCE attempts to add an LSP 532 not complying to this rule, the PCC MUST send PCErr with Error-Type = 533 29 (Early allocation by IANA) (Association Error) and Error-Value = 534 TBD4 (Bidirectional LSP Association - Group Mismatch). Similarly, if 535 a PCC attempts to add an LSP at PCE not complying to this rule, the 536 PCE MUST send this PCErr. 538 The LSPs (forward or reverse) in a single-sided bidirectional LSP 539 association group MUST belong to the same TE Tunnel (as defined in 540 [RFC3209]). If a PCE attempts to add an LSP in a single-sided 541 bidirectional LSP association group for a different Tunnel, the PCC 542 MUST send PCErr with Error-Type = 29 (Early allocation by IANA) 543 (Association Error) and Error-Value = TBD5 (Bidirectional LSP 544 Association - Tunnel Mismatch). Similarly, if a PCC attempts to add 545 an LSP to a single-sided bidirectional LSP association group at PCE 546 not complying to this rule, the PCE MUST send this PCErr. 548 The PCEP Path Setup Type (PST) MUST be set to 'Path is set up using 549 the RSVP-TE signaling protocol' (Value 0) [RFC8408] for the LSP 550 belonging to the Bidirectional LSP Association Groups defined in this 551 document. In case a PCEP speaker receives a different PST value for 552 this association group, it MUST return a PCErr message with Error- 553 Type = 29 (Early allocation by IANA) (Association Error) and Error- 554 Value = TBD6 (Bidirectional LSP Association - Path Setup Type 555 Mismatch). 557 The processing rules as specified in Section 5.4 of 558 [I-D.ietf-pce-association] continue to apply for the Association 559 Types defined in this document. 561 6. Implementation Status 563 [Note to the RFC Editor - remove this section before publication, as 564 well as remove the reference to RFC 7942.] 566 This section records the status of known implementations of the 567 protocol defined by this specification at the time of posting of this 568 Internet-Draft, and is based on a proposal described in [RFC7942]. 569 The description of implementations in this section is intended to 570 assist the IETF in its decision processes in progressing drafts to 571 RFCs. Please note that the listing of any individual implementation 572 here does not imply endorsement by the IETF. Furthermore, no effort 573 has been spent to verify the information presented here that was 574 supplied by IETF contributors. This is not intended as, and must not 575 be construed to be, a catalog of available implementations or their 576 features. Readers are advised to note that other implementations may 577 exist. 579 According to [RFC7942], "this will allow reviewers and working groups 580 to assign due consideration to documents that have the benefit of 581 running code, which may serve as evidence of valuable experimentation 582 and feedback that have made the implemented protocols more mature. 583 It is up to the individual working groups to use this information as 584 they see fit". 586 6.1. Implementation 588 The PCEP extensions defined in this document has been implemented by 589 a vendor on their product. No further information is available at 590 this time. 592 7. Security Considerations 594 The security considerations described in [RFC5440], [RFC8231], and 595 [RFC8281] apply to the extensions defined in this document as well. 597 Two new Association Types for the Association Object, Single-sided 598 Bidirectional LSP Association Group and Double-sided Associated 599 Bidirectional LSP Group are introduced in this document. Additional 600 security considerations related to LSP associations due to a 601 malicious PCEP speaker is described in [I-D.ietf-pce-association] and 602 apply to these Association Types. Hence, securing the PCEP session 603 using Transport Layer Security (TLS) [RFC8253] is recommended. 605 8. Manageability Considerations 607 8.1. Control of Function and Policy 609 The mechanisms defined in this document do not imply any control or 610 policy requirements in addition to those already listed in [RFC5440], 611 [RFC8231], and [RFC8281]. 613 8.2. Information and Data Models 615 [RFC7420] describes the PCEP MIB, there are no new MIB Objects 616 defined for LSP associations. 618 The PCEP YANG module [I-D.ietf-pce-pcep-yang] defines data model for 619 LSP associations. 621 8.3. Liveness Detection and Monitoring 623 The mechanisms defined in this document do not imply any new liveness 624 detection and monitoring requirements in addition to those already 625 listed in [RFC5440], [RFC8231], and [RFC8281]. 627 8.4. Verify Correct Operations 629 The mechanisms defined in this document do not imply any new 630 operation verification requirements in addition to those already 631 listed in [RFC5440], [RFC8231], and [RFC8281]. 633 8.5. Requirements On Other Protocols 635 The mechanisms defined in this document do not add any new 636 requirements on other protocols. 638 8.6. Impact On Network Operations 640 The mechanisms defined in this document do not have any impact on 641 network operations in addition to those already listed in [RFC5440], 642 [RFC8231], and [RFC8281]. 644 9. IANA Considerations 646 9.1. Association Types 648 This document adds new Association Types for the Association Object 649 defined [I-D.ietf-pce-association]. IANA is requested to make the 650 assignment of values for the sub-registry "ASSOCIATION Type Field" 651 (to be created in [I-D.ietf-pce-association]), as follows: 653 Value Name Reference 654 --------------------------------------------------------------------- 655 TBD1 Single-sided Bidirectional LSP Association Group [This document] 656 TBD2 Double-sided Bidirectional LSP Association Group [This document] 658 9.2. Bidirectional LSP Association Group TLV 660 This document defines a new TLV for carrying additional information 661 of LSPs within a Bidirectional LSP Association Group. IANA is 662 requested to add the assignment of a new value in the existing "PCEP 663 TLV Type Indicators" registry as follows: 665 TLV-Type Name Reference 666 ------------------------------------------------------------------- 667 TBD3 Bidirectional LSP Association Group TLV [This document] 669 9.2.1. Flag Fields in Bidirectional LSP Association Group TLV 671 This document requests that a new sub-registry, named "Bidirectional 672 LSP Association Group TLV Flag Field", is created within the "Path 673 Computation Element Protocol (PCEP) Numbers" registry to manage the 674 Flag field in the Bidirectional LSP Association Group TLV. New 675 values are to be assigned by Standards Action [RFC8126]. Each bit 676 should be tracked with the following qualities: 678 o Bit number (count from 0 as the most significant bit) 680 o Description 682 o Reference 684 The following values are defined in this document for the Flag field. 686 Bit No. Description Reference 687 --------------------------------------------------------- 688 31 F - Forward LSP [This document] 689 30 R - Reverse LSP [This document] 690 29 C - Co-routed LSP [This document] 692 9.3. PCEP Errors 694 This document defines new Error value for Error Type 29 (Association 695 Error). IANA is requested to allocate new Error value within the 696 "PCEP-ERROR Object Error Types and Values" sub-registry of the PCEP 697 Numbers registry, as follows: 699 Error Type Description Reference 700 --------------------------------------------------------------------- 701 29 Association Error 703 Error value: TBD4 [This document] 704 Bidirectional LSP Association - Group Mismatch 706 Error value: TBD5 [This document] 707 Bidirectional LSP Association - Tunnel Mismatch 709 Error value: TBD6 [This document] 710 Bidirectional LSP Association - Path Setup Type Mismatch 712 10. References 714 10.1. Normative References 716 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 717 Requirement Levels", BCP 14, RFC 2119, DOI 718 10.17487/RFC2119, March 1997. 720 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 721 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 722 Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001. 724 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 725 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 726 March 2009. 728 [RFC7551] Zhang, F., Ed., Jing, R., and R. Gandhi, Ed., "RSVP-TE 729 Extensions for Associated Bidirectional LSPs", RFC 7551, 730 May 2015. 732 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 733 Writing an IANA Considerations Section in RFCs", BCP 26, 734 RFC 8126, DOI 10.17487/RFC8126, June 2017. 736 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 737 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 738 May 2017, . 740 [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Pah 741 Computation Element Communication Protocol (PCEP) 742 Extensions for Stateful PCE", RFC 8231, DOI 743 10.17487/RFC8231, September 2017. 745 [RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "PCEP 746 Extensions for PCE-initiated LSP Setup in a Stateful PCE 747 Model", RFC 8281, December 2017. 749 [RFC8537] Gandhi, R., Ed., Shah, H., and J. Whittaker, "Updates to 750 the Fast Reroute Procedures for Co-routed Associated 751 Bidirectional Label Switched Paths (LSPs)", RFC 8537, 752 February 2019. 754 [I-D.ietf-pce-association] Minei, I., Crabbe, E., Sivabalan, S., 755 Ananthakrishnan, H., Dhody, D., and Y. Tanaka, "PCEP 756 Extensions for Establishing Relationships Between Sets of 757 LSPs", draft-ietf-pce-association-group (work in 758 progress). 760 10.2. Informative References 762 [RFC5654] Niven-Jenkins, B., Ed., Brungard, D., Ed., Betts, M., Ed., 763 Sprecher, N., and S. Ueno, "Requirements of an MPLS 764 Transport Profile", RFC 5654, September 2009. 766 [RFC7420] Koushik, A., Stephan, E., Zhao, Q., King, D., and J. 767 Hardwick, "Path Computation Element Communication Protocol 768 (PCEP) Management Information Base (MIB) Module", RFC 769 7420, December 2014. 771 [RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running 772 Code: The Implementation Status Section", BCP 205, RFC 773 7942, DOI 10.17487/RFC7942, July 2016, . 776 [RFC8051] Zhang, X., Ed. and I. Minei, Ed., "Applicability of a 777 Stateful Path Computation Element (PCE)", RFC 8051, 778 January 2017. 780 [RFC8253] Lopez, D., Dios, O., Wu, Q., and D. Dhody, "PCEPS: Usage 781 of TLS to Provide a Secure Transport for the Path 782 Computation Element Communication Protocol (PCEP)", RFC 783 8253, October 2017. 785 [RFC8408] Sivabalan, S., et al. "Conveying Path Setup Type in PCE 786 Communication Protocol (PCEP) Messages", RFC 8408, July 787 2018. 789 [I-D.ietf-pce-pcep-yang] Dhody, D., Hardwick, J., Beeram, V., and J. 790 Tantsura, "A YANG Data Model for Path Computation Element 791 Communications Protocol (PCEP)", draft-ietf-pce-pcep-yang 792 (work in progress). 794 Acknowledgments 796 The authors would like to thank Dhruv Dhody for various discussions 797 on association groups and inputs to this document. The authors would 798 also like to thank Dhruv Dhody, Mike Taillon, and Marina Fizgeer for 799 reviewing this document and providing valuable comments. 801 Authors' Addresses 803 Rakesh Gandhi (editor) 804 Cisco Systems, Inc. 805 Canada 807 Email: rgandhi@cisco.com 809 Colby Barth 810 Juniper Networks 812 Email: cbarth@juniper.net 814 Bin Wen 815 Comcast 817 Email: Bin_Wen@cable.comcast.com