idnits 2.17.1 draft-dhody-pce-pcep-p2mp-per-destination-11.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 (March 13, 2017) is 2600 days in the past. Is this intentional? Checking references for intended status: Experimental ---------------------------------------------------------------------------- == Outdated reference: A later version (-04) exists of draft-ietf-pce-rfc6006bis-00 == Outdated reference: A later version (-21) exists of draft-ietf-pce-stateful-pce-18 == Outdated reference: A later version (-11) exists of draft-ietf-pce-pce-initiated-lsp-09 == Outdated reference: A later version (-13) exists of draft-ietf-pce-stateful-pce-p2mp-02 Summary: 0 errors (**), 0 flaws (~~), 5 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 PCE Working Group D. Dhody 3 Internet-Draft U. Palle 4 Intended status: Experimental V. Kondreddy 5 Expires: September 14, 2017 Huawei Technologies 6 March 13, 2017 8 Supporting Explicit Inclusion or Exclusion of Abstract Nodes for a 9 Subset of P2MP Destinations in Path Computation Element Communication 10 Protocol (PCEP). 11 draft-dhody-pce-pcep-p2mp-per-destination-11 13 Abstract 15 The ability to determine paths of point-to-multipoint (P2MP) 16 Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) 17 Traffic Engineering Label Switched Paths (TE LSPs) is one the key 18 requirements for Path Computation Element (PCE). The PCEP has been 19 extentded for intra and inter domain path computation via PCE(s) for 20 P2MP TE LSP. 22 This document describes the motivation and PCEP extension for 23 explicitly specifying abstract nodes for inclusion or exclusion for a 24 subset of destinations during P2MP path computation via PCE(s). 26 Status of This Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at http://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on September 14, 2017. 43 Copyright Notice 45 Copyright (c) 2017 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents 50 (http://trustee.ietf.org/license-info) in effect on the date of 51 publication of this document. Please review these documents 52 carefully, as they describe your rights and restrictions with respect 53 to this document. Code Components extracted from this document must 54 include Simplified BSD License text as described in Section 4.e of 55 the Trust Legal Provisions and are provided without warranty as 56 described in the Simplified BSD License. 58 Table of Contents 60 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 61 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 62 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 63 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 4 64 3.1. Domain Sequence Tree in Inter Domain P2MP Path 65 Computation . . . . . . . . . . . . . . . . . . . . . . . 4 66 3.2. Explicit inclusion or exclusion of abstract nodes . . . . 6 67 4. Detailed Description . . . . . . . . . . . . . . . . . . . . 6 68 4.1. Objective . . . . . . . . . . . . . . . . . . . . . . . . 7 69 4.2. Request Message Format . . . . . . . . . . . . . . . . . 7 70 4.3. Report Message Format . . . . . . . . . . . . . . . . . . 9 71 4.4. Backward Compatibility . . . . . . . . . . . . . . . . . 10 72 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 73 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 74 7. Manageability Considerations . . . . . . . . . . . . . . . . 10 75 7.1. Control of Function and Policy . . . . . . . . . . . . . 10 76 7.2. Information and Data Models . . . . . . . . . . . . . . . 11 77 7.3. Liveness Detection and Monitoring . . . . . . . . . . . . 11 78 7.4. Verify Correct Operations . . . . . . . . . . . . . . . . 11 79 7.5. Requirements On Other Protocols . . . . . . . . . . . . . 11 80 7.6. Impact On Network Operations . . . . . . . . . . . . . . 11 81 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 82 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 83 9.1. Normative References . . . . . . . . . . . . . . . . . . 11 84 9.2. Informative References . . . . . . . . . . . . . . . . . 12 85 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 87 1. Introduction 89 The PCE architecture is defined in [RFC4655]. [RFC5862] lay out the 90 requirements for PCEP to support P2MP path computation. 91 [I-D.ietf-pce-rfc6006bis] describe an extension to PCEP to compute 92 optimal constrained intra-domain (G)MPLS P2MP TE LSPs. [RFC7334] 93 describes the mechanism for inter-domain P2MP path computation. 95 Further [I-D.ietf-pce-rfc6006bis] describes mechanism to specify a 96 list of nodes that can be used as branch nodes or a list of nodes 97 that cannot be used as branch nodes via Branch Node Capability (BNC) 98 object. The BNC object is used to specify which nodes have the 99 capability to act as a branch nodes or which nodes lack the 100 capabilty. It supports IPv4 and IPv6 prefix sub-objects only. 102 This document explains the need to add the capability to explicitly 103 specify any abstract nodes (not just nodes with branch node 104 capabiltiy) for inclusion or exclusion for a subset of destinations. 106 [RFC7334] describes the core-tree procedure to compute inter-domain 107 P2MP tree. It assumes that, due to deployment and commercial 108 limitations, the sequence of domains for a path (the path domain 109 tree) will be known in advance. For a group of destination which 110 belong to a particular destination domain, the domain-sequence needs 111 to be encoded separately as described in [RFC7897]. The mechanism, 112 as described in this document, of explicitly specifying abstract 113 nodes for inclusion or exclusion for a subset of destinations can be 114 used for this purpose, where abstract nodes are domains. 116 Stateful PCEs are shown to be helpful in many application scenarios, 117 in both MPLS and GMPLS networks, as illustrated in [RFC8051]. These 118 scenarios apply equally to P2P and P2MP TE LSPs. 119 [I-D.ietf-pce-stateful-pce] provides the fundamental extensions 120 needed for stateful PCE to support general functionality for P2P TE 121 LSP. [I-D.ietf-pce-pce-initiated-lsp] provides the an extensions 122 needed for stateful PCE-initiated P2P TE LSP. Complementarily, 123 [I-D.ietf-pce-stateful-pce-p2mp] focuses on the extensions that are 124 necessary in order for the deployment of stateful PCEs to support 125 P2MP TE LSPs. 127 1.1. Requirements Language 129 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 130 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 131 document are to be interpreted as described in [RFC2119]. 133 2. Terminology 135 The following terminology is used in this document. 137 IRO: Include Route Object. 139 PCC: Path Computation Client: any client application requesting a 140 path computation to be performed by a Path Computation Element. 142 PCE: Path Computation Element. An entity (component, application, 143 or network node) that is capable of computing a network path or 144 route based on a network graph and applying computational 145 constraints. 147 PCEP: Path Computation Element Protocol. 149 P2MP: Point-to-Multipoint 151 P2P: Point-to-Point 153 RRO: Record Route Object 155 RSVP: Resource Reservation Protocol 157 TE LSP: Traffic Engineering Label Switched Path. 159 XRO: Exclude Route Object. 161 3. Motivation 163 3.1. Domain Sequence Tree in Inter Domain P2MP Path Computation 165 [RFC7334] describes the core-tree procedure for inter-domain path 166 computation. The procedure assumes that the sequence of domains for 167 a path (the path domain tree) will be known in advance due to 168 deployment and commercial limitations (e.g., inter-AS peering 169 agreements). 171 In the Figure 1 below, D1 is the root domain; D4, D5 and D6 are the 172 destination domains. The ingress is Ro in domain D1; egresses are M, 173 N in Domain D4; R, S in Domain D5; and U, V in Domain D6. 175 +----------------+ 176 | |Domain D1 177 | Ro | 178 | | 179 | A | 180 | | 181 +-B------------C-+ 182 / \ 183 / \ 184 / \ 185 Domain D2 / \ Domain D3 186 +-------------D--+ +-----E----------+ 187 | | | | 188 | F | | | 189 | G | | H | 190 | | | | 191 | | | | 192 +-I--------------+ +-J------------K-+ 193 /\ / \ 194 / \ / \ 195 / \ / \ 196 / \ / \ 197 / \ / \ 198 / \ / \ 199 / Domain D4 \ Domain D5 / Domain D6 \ 200 +-L-------------W+ +------P---------+ +-----------T----+ 201 | | | | | | 202 | | | Q | | U | 203 | M O | | S | | | 204 | | | | | V | 205 | N | | R | | | 206 +----------------+ +----------------+ +----------------+ 208 Figure 1: Domain Topology Example 210 The domain tree can be represented as a series of domain sequences: 212 Domain D1, Domain D3, Domain D6 214 Domain D1, Domain D3, Domain D5 216 Domain D1, Domain D2, Domain D4 218 Since destinations in different destination domain will have 219 different domain sequence within the domain tree, it requires 220 following encoding that binds destinations to a particular domain 221 sequence. 223 o Destination M and N: D1-D2-D4 225 o Destination R and S: D1-D3-D5 227 o Destination U and V: D1-D3-D6 229 An extension in P2MP Path Computation request is needed to support 230 this. (Refer Section 4.2) 232 The abstract nodes MAY include (but not limited to) domain subobjects 233 - AS number and IGP Area as described in [RFC7897]. 235 3.2. Explicit inclusion or exclusion of abstract nodes 237 [I-D.ietf-pce-rfc6006bis] describes four possible types of leaves in 238 a P2MP request encoded in P2MP END-POINTS object. 240 o New leaves to add 242 o Old leaves to remove 244 o Old leaves whose path can be modified/reoptimized 246 o Old leaves whose path must be left unchanged 248 [I-D.ietf-pce-rfc6006bis] only allows to encode a list of nodes that 249 have (or have not) the branch node capability by using the Branch 250 Node Capability (BNC) Object. This object apply to all destinations 251 (old and new) in the P2MP tree. 253 For an existing P2MP tree with an overloaded branch node, when adding 254 a set of new leaves, administrator may want to exclude that 255 particular branch node to balance the final P2MP tree. This cannot 256 be achieved via the BNC object but by explicitly excluding a 257 particular node or including a different node, for the P2MP END- 258 POINTS object for new leaves only. 260 Administrator at the Ingress can exert stronger control by providing 261 explicit inclusion or exclusion of any abstract nodes (not limited to 262 specifying nodes with branch node capability) for a group (subset) of 263 destinations and not all destinations. 265 4. Detailed Description 266 4.1. Objective 268 [I-D.ietf-pce-rfc6006bis] and [I-D.ietf-pce-stateful-pce-p2mp] 269 defines Request Message Format and Objects, along with . This section introduce the use of and 271 which are added to the . 273 To allow abstract nodes to be explicitly included or excluded for a 274 subset of destinations (encoded in one object), changes 275 are made as shown below. 277 The abstract node (encoded as subobject in and ) MAY be an 278 absolute hop, IP-Prefix, AS or IGP Area. The subobjects are 279 described in [RFC3209], [RFC3477], [RFC4874] and [RFC7897]. 281 Note that one P2MP Path request can have multiple 282 objects and each P2MP object may have multiple 283 destinations, the , and is applied for all 284 destinations in one such P2MP object. 286 4.2. Request Message Format 288 The format of PCReq message, with [I-D.ietf-pce-stateful-pce-p2mp] as 289 base, is modified as follows: 291 ::= 292 [] 293 295 where: 297 ::= 298 [] 299 [] 300 [] 302 ::=[] 304 ::= 305 306 [] 307 [] 308 [] 309 [] 310 [] 311 [|] 312 [] 314 ::= 315 316 [] 317 [] 318 [][] 319 [] 321 ::=(|)[] 322 ::=[] 324 From [I-D.ietf-pce-rfc6006bis] and [I-D.ietf-pce-stateful-pce-p2mp], 325 usage of is changed to in this document. 328 [I-D.ietf-pce-rfc6006bis] describes Branch Node Capability (BNC) 329 Object which is different from the use of and to specify 330 inclusion/exclusion of abstract nodes for a subset of destinations as 331 described here. 333 4.3. Report Message Format 335 [I-D.ietf-pce-stateful-pce-p2mp] defines a report message format and 336 objects. This document extends the message to allow explicit 337 inclusion and exclusion of abstract nodes for a group of 338 destinations. 340 ::= 341 342 Where: 344 ::= 345 [] 347 ::= [] 348 349 350 [ 351 ] 352 354 Where: 356 ::= 357 [] 358 [] 359 [] 360 [] 361 362 [] 364 ::= 365 [] 366 [] 367 368 [] 370 ::= (|) 371 [] 373 ::= (|) 374 [] 376 is represented by the ERO, SERO object. The 377 consists of the actual computed and signaled 378 values of the and objects defined in 379 [RFC5440]. is represented by the RRO, SERO object. 381 The is extended to add the IRO 382 and XRO object for a group of destinations in the END-POINTS object. 384 4.4. Backward Compatibility 386 A legacy implementation that does not support explicit inclusion or 387 exclusion of abstract nodes for a subset of P2MP destinations will 388 act according to the procedures set out in [RFC5440], that is it will 389 find the P2MP Path Request message out of order with respect to the 390 format specified in [I-D.ietf-pce-rfc6006bis] and 391 [I-D.ietf-pce-stateful-pce-p2mp]. 393 5. IANA Considerations 395 There are no new IANA allocation in this document. 397 6. Security Considerations 399 PCEP security mechanisms as described in [RFC5440], 400 [I-D.ietf-pce-rfc6006bis], [RFC7334] and 401 [I-D.ietf-pce-stateful-pce-p2mp] are applicable for this document. 403 The new explicit inclusion or exclusion of abstract nodes for a 404 subset of P2MP destination defined in this document allow finer and 405 more specific control of the path computed by a PCE. Such control 406 increases the risk if a PCEP message is intercepted, modified, or 407 spoofed because it allows the attacker to exert control over the path 408 that the PCE will compute or to make the path computation impossible. 409 Therefore, the security techniques described in [RFC5440], 410 [I-D.ietf-pce-rfc6006bis], [RFC7334] and 411 [I-D.ietf-pce-stateful-pce-p2mp] are considered more important. 413 Note, however, that the route exclusion mechanisms also provide the 414 operator with the ability to route around vulnerable parts of the 415 network and may be used to increase overall network security. 417 7. Manageability Considerations 419 7.1. Control of Function and Policy 421 Mechanisms defined in this document do not add any new control 422 function/policy requirements in addition to those already listed in 423 [I-D.ietf-pce-rfc6006bis] and [I-D.ietf-pce-stateful-pce-p2mp]. 425 7.2. Information and Data Models 427 Mechanisms defined in this document do not imply any new MIB 428 requirements. 430 7.3. Liveness Detection and Monitoring 432 Mechanisms defined in this document do not imply any new liveness 433 detection and monitoring requirements in addition to those already 434 listed in [I-D.ietf-pce-rfc6006bis] and 435 [I-D.ietf-pce-stateful-pce-p2mp]. 437 7.4. Verify Correct Operations 439 Mechanisms defined in this document do not imply any new operation 440 verification requirements in addition to those already listed in 441 [I-D.ietf-pce-rfc6006bis] and [I-D.ietf-pce-stateful-pce-p2mp]. 443 7.5. Requirements On Other Protocols 445 Mechanisms defined in this document do not imply any requirements on 446 other protocols in addition to those already listed in 447 [I-D.ietf-pce-rfc6006bis] and [I-D.ietf-pce-stateful-pce-p2mp]. 449 7.6. Impact On Network Operations 451 Mechanisms defined in this document do not have any impact on network 452 operations in addition to those already listed in 453 [I-D.ietf-pce-rfc6006bis] and [I-D.ietf-pce-stateful-pce-p2mp]. 455 8. Acknowledgments 457 We would like to thank Pradeep Shastry, Suresh babu, Quintin Zhao, 458 Daniel King and Chen Huaimo for their useful comments and 459 suggestions. 461 9. References 463 9.1. Normative References 465 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 466 Requirement Levels", BCP 14, RFC 2119, 467 DOI 10.17487/RFC2119, March 1997, 468 . 470 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 471 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 472 DOI 10.17487/RFC5440, March 2009, 473 . 475 [I-D.ietf-pce-rfc6006bis] 476 Zhao, Q., Dhody, D., Palleti, R., King, D., Verhaeghe, F., 477 Takeda, T., and J. Meuric, "Extensions to the Path 478 Computation Element Communication Protocol (PCEP) for 479 Point-to-Multipoint Traffic Engineering Label Switched 480 Paths", draft-ietf-pce-rfc6006bis-00 (work in progress), 481 March 2017. 483 [I-D.ietf-pce-stateful-pce] 484 Crabbe, E., Minei, I., Medved, J., and R. Varga, "PCEP 485 Extensions for Stateful PCE", draft-ietf-pce-stateful- 486 pce-18 (work in progress), December 2016. 488 [I-D.ietf-pce-pce-initiated-lsp] 489 Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "PCEP 490 Extensions for PCE-initiated LSP Setup in a Stateful PCE 491 Model", draft-ietf-pce-pce-initiated-lsp-09 (work in 492 progress), March 2017. 494 [I-D.ietf-pce-stateful-pce-p2mp] 495 Palle, U., Dhody, D., Tanaka, Y., and V. Beeram, "Path 496 Computation Element (PCE) Protocol Extensions for Stateful 497 PCE usage for Point-to-Multipoint Traffic Engineering 498 Label Switched Paths", draft-ietf-pce-stateful-pce-p2mp-02 499 (work in progress), March 2017. 501 9.2. Informative References 503 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 504 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 505 Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, 506 . 508 [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links 509 in Resource ReSerVation Protocol - Traffic Engineering 510 (RSVP-TE)", RFC 3477, DOI 10.17487/RFC3477, January 2003, 511 . 513 [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation 514 Element (PCE)-Based Architecture", RFC 4655, 515 DOI 10.17487/RFC4655, August 2006, 516 . 518 [RFC4874] Lee, CY., Farrel, A., and S. De Cnodder, "Exclude Routes - 519 Extension to Resource ReserVation Protocol-Traffic 520 Engineering (RSVP-TE)", RFC 4874, DOI 10.17487/RFC4874, 521 April 2007, . 523 [RFC5862] Yasukawa, S. and A. Farrel, "Path Computation Clients 524 (PCC) - Path Computation Element (PCE) Requirements for 525 Point-to-Multipoint MPLS-TE", RFC 5862, 526 DOI 10.17487/RFC5862, June 2010, 527 . 529 [RFC7334] Zhao, Q., Dhody, D., King, D., Ali, Z., and R. Casellas, 530 "PCE-Based Computation Procedure to Compute Shortest 531 Constrained Point-to-Multipoint (P2MP) Inter-Domain 532 Traffic Engineering Label Switched Paths", RFC 7334, 533 DOI 10.17487/RFC7334, August 2014, 534 . 536 [RFC7897] Dhody, D., Palle, U., and R. Casellas, "Domain Subobjects 537 for the Path Computation Element Communication Protocol 538 (PCEP)", RFC 7897, DOI 10.17487/RFC7897, June 2016, 539 . 541 [RFC8051] Zhang, X., Ed. and I. Minei, Ed., "Applicability of a 542 Stateful Path Computation Element (PCE)", RFC 8051, 543 DOI 10.17487/RFC8051, January 2017, 544 . 546 Authors' Addresses 548 Dhruv Dhody 549 Huawei Technologies 550 Divyashree Techno Park, Whitefield 551 Bangalore, Karnataka 560066 552 India 554 EMail: dhruv.ietf@gmail.com 556 Udayasree Palle 557 Huawei Technologies 558 Divyashree Techno Park, Whitefield 559 Bangalore, Karnataka 560066 560 India 562 EMail: udayasree.palle@huawei.com 563 Venugopal Reddy Kondreddy 564 Huawei Technologies 565 Divyashree Techno Park, Whitefield 566 Bangalore, Karnataka 560066 567 India 569 EMail: venugopalreddyk@huawei.com