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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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-23) exists of draft-ietf-pce-pcep-yang-13 Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--).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: August 7, 2020 Juniper Networks 6 B. Wen 7 Comcast 8 February 4, 2020 10 PCEP Extensions for Associated Bidirectional Label Switched Paths (LSPs) 11 draft-ietf-pce-association-bidir-05 13 Abstract 15 The Path Computation Element Communication Protocol (PCEP) provides 16 mechanisms for Path Computation Elements (PCEs) to perform path 17 computations in response to Path Computation Clients (PCCs) requests. 18 The Stateful PCE extensions allow stateful control of Multiprotocol 19 Label Switching (MPLS) Traffic Engineering (TE) Label Switched Paths 20 (LSPs) using PCEP. 22 This document defines PCEP extensions for grouping two unidirectional 23 MPLS TE LSPs (one in each direction in the network) into an 24 Associated Bidirectional LSP. The mechanisms defined in this 25 document can be applied using a Stateful PCE for both PCE-Initiated 26 and PCC-Initiated LSPs, as well as when using a Stateless PCE. The 27 procedures defined are applicable to the LSPs using Resource 28 Reservation Protocol (RSVP) for 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 https://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 This Internet-Draft will expire on August 7, 2020. 47 Copyright Notice 49 Copyright (c) 2020 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (https://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 65 2. Conventions Used in This Document . . . . . . . . . . . . . . 4 66 2.1. Key Word Definitions . . . . . . . . . . . . . . . . . . 4 67 2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 68 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 4 69 3.1. Single-sided Initiation . . . . . . . . . . . . . . . . . 5 70 3.2. Double-sided Initiation . . . . . . . . . . . . . . . . . 6 71 3.3. Co-routed Associated Bidirectional LSP . . . . . . . . . 7 72 4. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 8 73 4.1. ASSOCIATION Object . . . . . . . . . . . . . . . . . . . 8 74 4.2. Bidirectional LSP Association Group TLV . . . . . . . . . 9 75 5. PCEP Procedure . . . . . . . . . . . . . . . . . . . . . . . 10 76 5.1. PCE Initiated LSPs . . . . . . . . . . . . . . . . . . . 10 77 5.2. PCC Initiated LSPs . . . . . . . . . . . . . . . . . . . 10 78 5.3. Stateless PCE . . . . . . . . . . . . . . . . . . . . . . 11 79 5.4. Bidirectional (B) Flag . . . . . . . . . . . . . . . . . 11 80 5.5. PLSP-ID Usage . . . . . . . . . . . . . . . . . . . . . . 11 81 5.6. State Synchronization . . . . . . . . . . . . . . . . . . 12 82 5.7. Error Handling . . . . . . . . . . . . . . . . . . . . . 12 83 6. Implementation Status . . . . . . . . . . . . . . . . . . . . 13 84 6.1. Implementation . . . . . . . . . . . . . . . . . . . . . 13 85 7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 86 8. Manageability Considerations . . . . . . . . . . . . . . . . 14 87 8.1. Control of Function and Policy . . . . . . . . . . . . . 14 88 8.2. Information and Data Models . . . . . . . . . . . . . . . 14 89 8.3. Liveness Detection and Monitoring . . . . . . . . . . . . 14 90 8.4. Verify Correct Operations . . . . . . . . . . . . . . . . 14 91 8.5. Requirements On Other Protocols . . . . . . . . . . . . . 14 92 8.6. Impact On Network Operations . . . . . . . . . . . . . . 14 93 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 94 9.1. Association Types . . . . . . . . . . . . . . . . . . . . 14 95 9.2. Bidirectional LSP Association Group TLV . . . . . . . . . 15 96 9.2.1. Flag Fields in Bidirectional LSP Association Group 97 TLV . . . . . . . . . . . . . . . . . . . . . . . . . 15 98 9.3. PCEP Errors . . . . . . . . . . . . . . . . . . . . . . . 15 99 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 100 10.1. Normative References . . . . . . . . . . . . . . . . . . 16 101 10.2. Informative References . . . . . . . . . . . . . . . . . 17 102 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 18 103 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 105 1. Introduction 107 [RFC5440] describes the Path Computation Element Protocol (PCEP) as a 108 communication mechanism between a Path Computation Client (PCC) and a 109 Path Control Element (PCE), or between PCE and PCC, that enables 110 computation of Multiprotocol Label Switching (MPLS) Traffic 111 Engineering (TE) Label Switched Paths (LSPs). 113 [RFC8231] specifies extensions to PCEP to enable stateful control of 114 MPLS TE LSPs. It describes two modes of operation - Passive Stateful 115 PCE and Active Stateful PCE. In [RFC8231], the focus is on Active 116 Stateful PCE where LSPs are provisioned on the PCC and control over 117 them is delegated to a PCE. Further, [RFC8281] describes the setup, 118 maintenance and teardown of PCE-Initiated LSPs for the Stateful PCE 119 model. 121 [RFC8697] introduces a generic mechanism to create a grouping of LSPs 122 which can then be used to define associations between a set of LSPs 123 and/or a set of attributes, for example primary and secondary LSP 124 associations, and is equally applicable to the active and passive 125 modes of a Stateful PCE [RFC8231] or a stateless PCE [RFC5440]. 127 The MPLS Transport Profile (MPLS-TP) requirements document [RFC5654] 128 specifies that MPLS-TP MUST support associated bidirectional point- 129 to-point LSPs. [RFC7551] defines RSVP signaling extensions for 130 binding two reverse unidirectional LSPs [RFC3209] into an associated 131 bidirectional LSP. The fast reroute (FRR) procedures for associated 132 bidirectional LSPs are described in [RFC8537]. 134 This document defines PCEP extensions for grouping two unidirectional 135 MPLS-TE LSPs into an Associated Bidirectional LSP for both single- 136 sided and double-sided initiation cases when using a Stateful PCE for 137 both PCE-Initiated and PCC-Initiated LSPs as well as when using a 138 Stateless PCE. The procedures defined are applicable to the LSPs 139 using Resource Reservation Protocol (RSVP) for signaling [RFC3209]. 140 The PCEP extensions cover the following cases: 142 o A PCC initiates the forward and/ or reverse LSP of a single-sided 143 or double-sided bidirectional LSP and retains the control of the 144 LSP. The PCC computes the path itself or makes a request for path 145 computation to a PCE. After the path setup, it reports the 146 information and state of the path to the PCE. This includes the 147 association group identifying the bidirectional LSP. This is the 148 Passive Stateful mode defined in [RFC8051]. 150 o A PCC initiates the forward and/ or reverse LSP of a single-sided 151 or double-sided bidirectional LSP and delegates the control of the 152 LSP to a Stateful PCE. During delegation the association group 153 identifying the bidirectional LSP is included. The PCE computes 154 the path of the LSP and updates the PCC with the information about 155 the path as long as it controls the LSP. This is the Active 156 Stateful mode defined in [RFC8051]. 158 o A PCE initiates the forward and/ or reverse LSP of a single-sided 159 or double-sided bidirectional LSP on a PCC and retains the control 160 of the LSP. The PCE is responsible for computing the path of the 161 LSP and updating the PCC with the information about the path as 162 well as the association group identifying the bidirectional LSP. 163 This is the PCE-Initiated mode defined in [RFC8281]. 165 o A PCC requests co-routed or non co-routed paths for forward and 166 reverse LSPs of a bidirectional LSP from a Stateless PCE 167 [RFC5440]. 169 2. Conventions Used in This Document 171 2.1. Key Word Definitions 173 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 174 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 175 "OPTIONAL" in this document are to be interpreted as described in BCP 176 14 [RFC2119] [RFC8174] when, and only when, they appear in all 177 capitals, as shown here. 179 2.2. Terminology 181 The reader is assumed to be familiar with the terminology defined in 182 [RFC5440], [RFC7551], [RFC8231], and [RFC8697]. 184 3. Overview 186 As shown in Figure 1, two reverse unidirectional LSPs can be grouped 187 to form an associated bidirectional LSP. There are two methods of 188 initiating the bidirectional LSP association, single-sided and 189 double-sided, as defined in [RFC7551] and described in the following 190 sections. 192 LSP1 --> LSP1 --> LSP1 --> 193 +-----+ +-----+ +-----+ +-----+ 194 | A +-----------+ B +-----------+ C +-----------+ D | 195 +-----+ +--+--+ +--+--+ +-----+ 196 <-- LSP2 | | <-- LSP2 197 | | 198 | | 199 +--+--+ +--+--+ 200 | E +-----------+ F | 201 +-----+ +-----+ 202 <-- LSP2 204 Figure 1: Example of Associated Bidirectional LSP 206 3.1. Single-sided Initiation 208 As specified in [RFC7551], in the single-sided case, the 209 bidirectional tunnel is provisioned only on one endpoint node (PCC) 210 of the tunnel. Both forward and reverse LSPs of this tunnel are 211 initiated with the Association Type set to "Single-sided 212 Bidirectional LSP Association" on the originating endpoint node. The 213 forward and reverse LSPs are identified in the Bidirectional LSP 214 Association Group TLV of their PCEP ASSOCIATION Objects. 216 The originating endpoint node signals the properties for the revere 217 LSP in the RSVP REVERSE_LSP Object [RFC7551] of the forward LSP Path 218 message. The remote endpoint then creates the corresponding reverse 219 tunnel and signals the reverse LSP in response to the received RSVP 220 Path message. Similarly, the remote endpoint node deletes the 221 reverse LSP when it receives the RSVP Path delete message [RFC3209] 222 for the forward LSP. 224 The originating endpoint (PCC) node may report/ delegate the forward 225 and reverse direction LSPs to a PCE. The remote endpoint (PCC) node 226 may report its forward direction LSP to a PCE. 228 +-----+ 229 | PCE | 230 +-----+ 231 Initiates: | ^ Reports: 232 Tunnel 1 (F) | \ Tunnel 2 (F) 233 (LSP1 (F), LSP2 (R)) | \ (LSP2 (F)) 234 Association #1 v \ Association #1 235 +-----+ +-----+ 236 | A | | D | 237 +-----+ +-----+ 239 Figure 2: Example of PCE-Initiated Single-sided Bidirectional LSP 241 +-----+ 242 | PCE | 243 +-----+ 244 Reports/Delegates: ^ ^ Reports: 245 Tunnel 1 (F) | \ Tunnel 2 (F) 246 (LSP1 (F), LSP2 (R)) | \ (LSP2 (F)) 247 Association #2 | \ Association #2 248 +-----+ +-----+ 249 | A | | D | 250 +-----+ +-----+ 252 Figure 3: Example of PCC-Initiated Single-sided Bidirectional LSP 254 As shown in Figures 2 and 3, the forward tunnel and both forward LSP1 255 and reverse LSP2 are initiated on the originating endpoint node A, 256 either by the PCE or the originating PCC, respectively. The 257 originating endpoint node A signals the properties of reverse LSP2 in 258 the RSVP REVERSE_LSP Object in the Path message of the forward LSP1. 259 The creation of reverse tunnel and reverse LSP2 on the remote 260 endpoint node D is triggered by the RSVP signaled forward LSP1. 262 As specified in [RFC8537], for fast reroute bypass tunnel assignment, 263 the LSP starting from the originating node is identified as the 264 forward LSP of the single-sided initiated bidirectional LSP. 266 3.2. Double-sided Initiation 268 As specified in [RFC7551], in the double-sided case, the 269 bidirectional tunnel is provisioned on both endpoint nodes (PCCs) of 270 the tunnel. The forward and reverse LSPs of this tunnel are 271 initiated with the Association Type set to "Double-sided 272 Bidirectional LSP Association" on both endpoint nodes. The forward 273 and reverse LSPs are identified in the Bidirectional LSP Association 274 Group TLV of their ASSOCIATION Objects. 276 The endpoint (PCC) nodes may report/ delegate the forward and reverse 277 direction LSPs to a PCE. 279 +-----+ 280 | PCE | 281 +-----+ 282 Initiates: | \ Initiates: 283 Tunnel 1 (F) | \ Tunnel 2 (F) 284 (LSP1 (F)) | \ (LSP2 (F)) 285 Association #3 v v Association #3 286 +-----+ +-----+ 287 | A | | D | 288 +-----+ +-----+ 290 Figure 4: Example of PCE-Initiated Double-sided Bidirectional LSP 292 +-----+ 293 | PCE | 294 +-----+ 295 Reports/Delegates: ^ ^ Reports/Delegates: 296 Tunnel 1 (F) | \ Tunnel 2 (F) 297 (LSP1 (F)) | \ (LSP2 (F)) 298 Association #4 | \ Association #4 299 +-----+ +-----+ 300 | A | | D | 301 +-----+ +-----+ 303 Figure 5: Example of PCC-Initiated Double-sided Bidirectional LSP 305 As shown in Figures 4 and 5, the forward tunnel and forward LSP1 are 306 initiated on the endpoint node A and the reverse tunnel and reverse 307 LSP2 are initiated on the endpoint node D, either by the PCE or the 308 PCCs, respectively. 310 As specified in [RFC8537], for fast reroute bypass tunnel assignment, 311 the LSP with the higher Source Address [RFC3209] is identified as the 312 forward LSP of the double-sided initiated bidirectional LSP. 314 3.3. Co-routed Associated Bidirectional LSP 316 In both single-sided and double-sided initiation cases, forward and 317 reverse LSPs may be co-routed as shown in Figure 6, where both 318 forward and reverse LSPs of a bidirectional LSP follow the same 319 congruent path in the forward and reverse directions, respectively. 321 LSP3 --> LSP3 --> LSP3 --> 322 +-----+ +-----+ +-----+ +-----+ 323 | A +-----------+ B +-----------+ C +-----------+ D | 324 +-----+ +-----+ +-----+ +-----+ 325 <-- LSP4 <-- LSP4 <-- LSP4 327 Figure 6: Example of Co-routed Associated Bidirectional LSP 329 4. Protocol Extensions 331 4.1. ASSOCIATION Object 333 As per [RFC8697], LSPs are associated by adding them to a common 334 association group. This document defines two new Bidirectional LSP 335 Association Groups to be used by the associated bidirectional LSPs. 336 A member of the Bidirectional LSP Association Group can take the role 337 of a forward or reverse LSP and follows the 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 (Object-Class value 40) 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 (Value 29) 361 [RFC8697] MUST NOT be sent for these Association Types, and MUST be 362 ignored, so that the entire range of association ID can be used for 363 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 [RFC8697] 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 7: 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 7: 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 Path, 1 bit) - Indicates whether the bidirectional LSP 422 is 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 co- 427 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 [RFC8697], the Bidirectional LSP Association Groups 437 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 [RFC8697]. 450 5.2. PCC Initiated LSPs 452 As specified in [RFC8697], Bidirectional LSP Association Groups can 453 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 [RFC8697]. 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 an LSP and it remains the same 503 for the lifetime of a PCEP session. 505 In case of Single-sided Bidirectional LSP Association, the reverse 506 LSP of a bidirectional LSP created on the originating node is 507 identified by the PCE using 2 different PLSP-IDs based on the PCEP 508 session on the ingress or egress nodes for the LSP. In other words, 509 the reverse LSP on the originating node will have a PLSP-ID A at the 510 ingress node while it will have a PLSP-ID B at the egress node. This 511 is not the case for the forward LSP of the Single-sided Bidirectional 512 LSP on the originating node and there is no change in the PLSP-ID 513 allocation procedure for it. In case of Double-sided Bidirectional 514 LSP Association, there is no change in the PLSP-ID allocation 515 procedure. 517 For an Associated Bidirectional LSP, LSP-IDENTIFIERS TLV [RFC8231] 518 MUST be included in all forward and reverse LSPs. 520 5.6. State Synchronization 522 During state synchronization, a PCC MUST report all the existing 523 Bidirectional LSP Association Groups to the Stateful PCE as per 524 [RFC8697]. After the state synchronization, the PCE MUST remove all 525 stale Bidirectional LSP Associations. 527 5.7. Error Handling 529 An LSP (forward or reverse) can not be part of more than one 530 Bidirectional LSP Association Group. If a PCE attempts to add an LSP 531 not complying to this rule, the PCC MUST send PCErr with Error-Type = 532 26 (Association Error) and Error-Value = TBD4 (Bidirectional LSP 533 Association - Group Mismatch). Similarly, if a PCC attempts to add 534 an LSP at PCE not complying to this rule, the PCE MUST send this 535 PCErr. 537 The LSPs (forward or reverse) in a Single-sided Bidirectional 538 Association Group MUST belong to the same TE Tunnel (as defined in 539 [RFC3209]). If a PCE attempts to add an LSP in a Single-sided 540 Bidirectional LSP Association Group for a different Tunnel, the PCC 541 MUST send PCErr with Error-Type = 26 (Association Error) and Error- 542 Value = TBD5 (Bidirectional Association - Tunnel Mismatch). 543 Similarly, if a PCC attempts to add an LSP to a Single-sided 544 Bidirectional LSP Association Group at PCE not complying to this 545 rule, the PCE MUST send this PCErr. 547 The PCEP Path Setup Type (PST) MUST be set to 'Path is set up using 548 the RSVP-TE signaling protocol' (Value 0) [RFC8408] for the LSP 549 belonging to the Bidirectional LSP Association Groups defined in this 550 document. In case a PCEP speaker receives a different PST value for 551 this association group, it MUST return a PCErr message with Error- 552 Type = 26 (Association Error) and Error-Value = TBD6 (Bidirectional 553 LSP Association - Path Setup Type Mismatch). 555 The processing rules as specified in Section 6.4 of [RFC8697] 556 continue to apply to the Association Types defined in this document. 558 6. Implementation Status 560 [Note to the RFC Editor - remove this section before publication, as 561 well as remove the reference to RFC 7942.] 563 This section records the status of known implementations of the 564 protocol defined by this specification at the time of posting of this 565 Internet-Draft, and is based on a proposal described in [RFC7942]. 566 The description of implementations in this section is intended to 567 assist the IETF in its decision processes in progressing drafts to 568 RFCs. Please note that the listing of any individual implementation 569 here does not imply endorsement by the IETF. Furthermore, no effort 570 has been spent to verify the information presented here that was 571 supplied by IETF contributors. This is not intended as, and must not 572 be construed to be, a catalog of available implementations or their 573 features. Readers are advised to note that other implementations may 574 exist. 576 According to [RFC7942], "this will allow reviewers and working groups 577 to assign due consideration to documents that have the benefit of 578 running code, which may serve as evidence of valuable experimentation 579 and feedback that have made the implemented protocols more mature. 580 It is up to the individual working groups to use this information as 581 they see fit". 583 6.1. Implementation 585 The PCEP extensions defined in this document has been implemented by 586 a vendor on their product. No further information is available at 587 this time. 589 7. Security Considerations 591 The security considerations described in [RFC5440], [RFC8231], and 592 [RFC8281] apply to the extensions defined in this document as well. 594 Two new Association Types for the ASSOCIATION Object, Single-sided 595 Bidirectional LSP Association Group and Double-sided Bidirectional 596 LSP Association Group are introduced in this document. Additional 597 security considerations related to LSP associations due to a 598 malicious PCEP speaker is described in [RFC8697] and apply to these 599 Association Types. Hence, securing the PCEP session using Transport 600 Layer Security (TLS) [RFC8253] is recommended. 602 8. Manageability Considerations 604 8.1. Control of Function and Policy 606 The mechanisms defined in this document do not imply any control or 607 policy requirements in addition to those already listed in [RFC5440], 608 [RFC8231], and [RFC8281]. 610 8.2. Information and Data Models 612 [RFC7420] describes the PCEP MIB, there are no new MIB Objects 613 defined for LSP associations. 615 The PCEP YANG module [I-D.ietf-pce-pcep-yang] defines data model for 616 LSP associations. 618 8.3. Liveness Detection and Monitoring 620 The mechanisms defined in this document do not imply any new liveness 621 detection and monitoring requirements in addition to those already 622 listed in [RFC5440], [RFC8231], and [RFC8281]. 624 8.4. Verify Correct Operations 626 The mechanisms defined in this document do not imply any new 627 operation verification requirements in addition to those already 628 listed in [RFC5440], [RFC8231], and [RFC8281]. 630 8.5. Requirements On Other Protocols 632 The mechanisms defined in this document do not add any new 633 requirements on other protocols. 635 8.6. Impact On Network Operations 637 The mechanisms defined in this document do not have any impact on 638 network operations in addition to those already listed in [RFC5440], 639 [RFC8231], and [RFC8281]. 641 9. IANA Considerations 643 9.1. Association Types 645 This document adds new Association Types for the ASSOCIATION Object 646 (Object-class value 40) defined [RFC8697]. IANA is requested to make 647 the assignment of values for the sub-registry "ASSOCIATION Type 648 Field" [RFC8697], as follows: 650 Type Name Reference 651 --------------------------------------------------------------------- 652 TBD1 Single-sided Bidirectional LSP Association Group [This document] 653 TBD2 Double-sided Bidirectional LSP Association Group [This document] 655 9.2. Bidirectional LSP Association Group TLV 657 This document defines a new TLV for carrying additional information 658 of LSPs within a Bidirectional LSP Association Group. IANA is 659 requested to add the assignment of a new value in the existing "PCEP 660 TLV Type Indicators" registry as follows: 662 Value Meaning Reference 663 ------------------------------------------------------------------- 664 TBD3 Bidirectional LSP Association Group TLV [This document] 666 9.2.1. Flag Fields in Bidirectional LSP Association Group TLV 668 This document requests that a new sub-registry, named "Bidirectional 669 LSP Association Group TLV Flag Field", is created within the "Path 670 Computation Element Protocol (PCEP) Numbers" registry to manage the 671 Flag field in the Bidirectional LSP Association Group TLV. New 672 values are to be assigned by Standards Action [RFC8126]. Each bit 673 should be tracked with the following qualities: 675 o Bit number (count from 0 as the most significant bit) 677 o Description 679 o Reference 681 The following values are defined in this document for the Flag field. 683 Bit No. Description Reference 684 --------------------------------------------------------- 685 31 F - Forward LSP [This document] 686 30 R - Reverse LSP [This document] 687 29 C - Co-routed Path [This document] 689 9.3. PCEP Errors 691 This document defines new Error value for Error Type 26 (Association 692 Error). IANA is requested to allocate new Error value within the 693 "PCEP-ERROR Object Error Types and Values" sub-registry of the PCEP 694 Numbers registry, as follows: 696 Error Type Description Reference 697 --------------------------------------------------------- 698 26 Association Error 700 Error value: TBD4 [This document] 701 Bidirectional LSP Association - Group Mismatch 703 Error value: TBD5 [This document] 704 Bidirectional LSP Association - Tunnel Mismatch 706 Error value: TBD6 [This document] 707 Bidirectional LSP Association - Path Setup Type Mismatch 709 10. References 711 10.1. Normative References 713 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 714 Requirement Levels", BCP 14, RFC 2119, 715 DOI 10.17487/RFC2119, March 1997, 716 . 718 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 719 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 720 Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, 721 . 723 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 724 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 725 DOI 10.17487/RFC5440, March 2009, 726 . 728 [RFC7551] Zhang, F., Ed., Jing, R., and R. Gandhi, Ed., "RSVP-TE 729 Extensions for Associated Bidirectional Label Switched 730 Paths (LSPs)", RFC 7551, DOI 10.17487/RFC7551, May 2015, 731 . 733 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 734 Writing an IANA Considerations Section in RFCs", BCP 26, 735 RFC 8126, DOI 10.17487/RFC8126, June 2017, 736 . 738 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 739 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 740 May 2017, . 742 [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path 743 Computation Element Communication Protocol (PCEP) 744 Extensions for Stateful PCE", RFC 8231, 745 DOI 10.17487/RFC8231, September 2017, 746 . 748 [RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path 749 Computation Element Communication Protocol (PCEP) 750 Extensions for PCE-Initiated LSP Setup in a Stateful PCE 751 Model", RFC 8281, DOI 10.17487/RFC8281, December 2017, 752 . 754 [RFC8537] Gandhi, R., Ed., Shah, H., and J. Whittaker, "Updates to 755 the Fast Reroute Procedures for Co-routed Associated 756 Bidirectional Label Switched Paths (LSPs)", RFC 8537, 757 DOI 10.17487/RFC8537, February 2019, 758 . 760 [RFC8697] Minei, I., Crabbe, E., Sivabalan, S., Ananthakrishnan, H., 761 Dhody, D., and Y. Tanaka, "Path Computation Element 762 Communication Protocol (PCEP) Extensions for Establishing 763 Relationships between Sets of Label Switched Paths 764 (LSPs)", RFC 8697, DOI 10.17487/RFC8697, January 2020, 765 . 767 10.2. Informative References 769 [I-D.ietf-pce-pcep-yang] 770 Dhody, D., Hardwick, J., Beeram, V., and J. Tantsura, "A 771 YANG Data Model for Path Computation Element 772 Communications Protocol (PCEP)", draft-ietf-pce-pcep- 773 yang-13 (work in progress), October 2019. 775 [RFC5654] Niven-Jenkins, B., Ed., Brungard, D., Ed., Betts, M., Ed., 776 Sprecher, N., and S. Ueno, "Requirements of an MPLS 777 Transport Profile", RFC 5654, DOI 10.17487/RFC5654, 778 September 2009, . 780 [RFC7420] Koushik, A., Stephan, E., Zhao, Q., King, D., and J. 781 Hardwick, "Path Computation Element Communication Protocol 782 (PCEP) Management Information Base (MIB) Module", 783 RFC 7420, DOI 10.17487/RFC7420, December 2014, 784 . 786 [RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running 787 Code: The Implementation Status Section", BCP 205, 788 RFC 7942, DOI 10.17487/RFC7942, July 2016, 789 . 791 [RFC8051] Zhang, X., Ed. and I. Minei, Ed., "Applicability of a 792 Stateful Path Computation Element (PCE)", RFC 8051, 793 DOI 10.17487/RFC8051, January 2017, 794 . 796 [RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody, 797 "PCEPS: Usage of TLS to Provide a Secure Transport for the 798 Path Computation Element Communication Protocol (PCEP)", 799 RFC 8253, DOI 10.17487/RFC8253, October 2017, 800 . 802 [RFC8408] Sivabalan, S., Tantsura, J., Minei, I., Varga, R., and J. 803 Hardwick, "Conveying Path Setup Type in PCE Communication 804 Protocol (PCEP) Messages", RFC 8408, DOI 10.17487/RFC8408, 805 July 2018, . 807 Acknowledgments 809 The authors would like to thank Dhruv Dhody for various discussions 810 on association groups and inputs to this document. The authors would 811 also like to thank Dhruv Dhody, Mike Taillon, and Marina Fizgeer for 812 reviewing this document and providing valuable comments. 814 Authors' Addresses 816 Rakesh Gandhi (editor) 817 Cisco Systems, Inc. 818 Canada 820 Email: rgandhi@cisco.com 822 Colby Barth 823 Juniper Networks 825 Email: cbarth@juniper.net 827 Bin Wen 828 Comcast 830 Email: Bin_Wen@cable.comcast.com