idnits 2.17.1 draft-dhody-pce-pcep-p2mp-per-destination-12.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 27, 2017) is 2402 days in the past. Is this intentional? Checking references for intended status: Experimental ---------------------------------------------------------------------------- == Outdated reference: A later version (-11) exists of draft-ietf-pce-pce-initiated-lsp-10 == Outdated reference: A later version (-13) exists of draft-ietf-pce-stateful-pce-p2mp-04 Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--).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 R. Palleti 4 Intended status: Experimental U. Palle 5 Expires: March 31, 2018 V. Kondreddy 6 Huawei Technologies 7 September 27, 2017 9 Supporting Explicit Inclusion or Exclusion of Abstract Nodes for a 10 Subset of P2MP Destinations in Path Computation Element Communication 11 Protocol (PCEP). 12 draft-dhody-pce-pcep-p2mp-per-destination-12 14 Abstract 16 The ability to determine paths of point-to-multipoint (P2MP) 17 Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) 18 Traffic Engineering Label Switched Paths (TE LSPs) is one the key 19 requirements for Path Computation Element (PCE). The PCEP has been 20 extentded for intra and inter domain path computation via PCE(s) for 21 P2MP TE LSP. 23 This document describes the motivation and PCEP extension for 24 explicitly specifying abstract nodes for inclusion or exclusion for a 25 subset of destinations during P2MP path computation via PCE(s). 27 Status of This Memo 29 This Internet-Draft is submitted in full conformance with the 30 provisions of BCP 78 and BCP 79. 32 Internet-Drafts are working documents of the Internet Engineering 33 Task Force (IETF). Note that other groups may also distribute 34 working documents as Internet-Drafts. The list of current Internet- 35 Drafts is at https://datatracker.ietf.org/drafts/current/. 37 Internet-Drafts are draft documents valid for a maximum of six months 38 and may be updated, replaced, or obsoleted by other documents at any 39 time. It is inappropriate to use Internet-Drafts as reference 40 material or to cite them other than as "work in progress." 42 This Internet-Draft will expire on March 31, 2018. 44 Copyright Notice 46 Copyright (c) 2017 IETF Trust and the persons identified as the 47 document authors. All rights reserved. 49 This document is subject to BCP 78 and the IETF Trust's Legal 50 Provisions Relating to IETF Documents 51 (https://trustee.ietf.org/license-info) in effect on the date of 52 publication of this document. Please review these documents 53 carefully, as they describe your rights and restrictions with respect 54 to this document. Code Components extracted from this document must 55 include Simplified BSD License text as described in Section 4.e of 56 the Trust Legal Provisions and are provided without warranty as 57 described in the Simplified BSD License. 59 Table of Contents 61 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 62 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 63 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 64 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 4 65 3.1. Domain Sequence Tree in Inter Domain P2MP Path 66 Computation . . . . . . . . . . . . . . . . . . . . . . . 4 67 3.2. Explicit inclusion or exclusion of abstract nodes . . . . 6 68 4. Detailed Description . . . . . . . . . . . . . . . . . . . . 6 69 4.1. Objective . . . . . . . . . . . . . . . . . . . . . . . . 7 70 4.2. Request Message Format . . . . . . . . . . . . . . . . . 7 71 4.3. Report Message Format . . . . . . . . . . . . . . . . . . 9 72 4.4. Backward Compatibility . . . . . . . . . . . . . . . . . 10 73 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 74 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 75 7. Manageability Considerations . . . . . . . . . . . . . . . . 10 76 7.1. Control of Function and Policy . . . . . . . . . . . . . 10 77 7.2. Information and Data Models . . . . . . . . . . . . . . . 11 78 7.3. Liveness Detection and Monitoring . . . . . . . . . . . . 11 79 7.4. Verify Correct Operations . . . . . . . . . . . . . . . . 11 80 7.5. Requirements On Other Protocols . . . . . . . . . . . . . 11 81 7.6. Impact On Network Operations . . . . . . . . . . . . . . 11 82 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 83 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 84 9.1. Normative References . . . . . . . . . . . . . . . . . . 11 85 9.2. Informative References . . . . . . . . . . . . . . . . . 12 86 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 88 1. Introduction 90 The PCE architecture is defined in [RFC4655]. [RFC5862] lay out the 91 requirements for PCEP to support P2MP path computation. 92 [I-D.ietf-pce-rfc6006bis] describe an extension to PCEP to compute 93 optimal constrained intra-domain (G)MPLS P2MP TE LSPs. [RFC7334] 94 describes the mechanism for inter-domain P2MP path computation. 96 Further [I-D.ietf-pce-rfc6006bis] describes mechanism to specify a 97 list of nodes that can be used as branch nodes or a list of nodes 98 that cannot be used as branch nodes via Branch Node Capability (BNC) 99 object. The BNC object is used to specify which nodes have the 100 capability to act as a branch nodes or which nodes lack the 101 capabilty. It supports IPv4 and IPv6 prefix sub-objects only. 103 This document explains the need to add the capability to explicitly 104 specify any abstract nodes (not just nodes with branch node 105 capabiltiy) for inclusion or exclusion for a subset of destinations. 107 [RFC7334] describes the core-tree procedure to compute inter-domain 108 P2MP tree. It assumes that, due to deployment and commercial 109 limitations, the sequence of domains for a path (the path domain 110 tree) will be known in advance. For a group of destination which 111 belong to a particular destination domain, the domain-sequence needs 112 to be encoded separately as described in [RFC7897]. The mechanism, 113 as described in this document, of explicitly specifying abstract 114 nodes for inclusion or exclusion for a subset of destinations can be 115 used for this purpose, where abstract nodes are domains. 117 Stateful PCEs are shown to be helpful in many application scenarios, 118 in both MPLS and GMPLS networks, as illustrated in [RFC8051]. These 119 scenarios apply equally to P2P and P2MP TE LSPs. [RFC8231] provides 120 the fundamental extensions needed for stateful PCE to support general 121 functionality for P2P TE LSP. [I-D.ietf-pce-pce-initiated-lsp] 122 provides the an extensions needed for stateful PCE-initiated P2P TE 123 LSP. Complementarily, [I-D.ietf-pce-stateful-pce-p2mp] focuses on 124 the extensions that are necessary in order for the deployment of 125 stateful PCEs to support P2MP TE LSPs. 127 1.1. Requirements Language 129 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 130 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 131 "OPTIONAL" in this document are to be interpreted as described in BCP 132 14 [RFC2119] [RFC8174] when, and only when, they appear in all 133 capitals, as shown here. 135 2. Terminology 137 The following terminology is used in this document. 139 IRO: Include Route Object. 141 PCC: Path Computation Client: any client application requesting a 142 path computation to be performed by a Path Computation Element. 144 PCE: Path Computation Element. An entity (component, application, 145 or network node) that is capable of computing a network path or 146 route based on a network graph and applying computational 147 constraints. 149 PCEP: Path Computation Element Protocol. 151 P2MP: Point-to-Multipoint 153 P2P: Point-to-Point 155 RRO: Record Route Object 157 RSVP: Resource Reservation Protocol 159 TE LSP: Traffic Engineering Label Switched Path. 161 XRO: Exclude Route Object. 163 3. Motivation 165 3.1. Domain Sequence Tree in Inter Domain P2MP Path Computation 167 [RFC7334] describes the core-tree procedure for inter-domain path 168 computation. The procedure assumes that the sequence of domains for 169 a path (the path domain tree) will be known in advance due to 170 deployment and commercial limitations (e.g., inter-AS peering 171 agreements). 173 In the Figure 1 below, D1 is the root domain; D4, D5 and D6 are the 174 destination domains. The ingress is Ro in domain D1; egresses are M, 175 N in Domain D4; R, S in Domain D5; and U, V in Domain D6. 177 +----------------+ 178 | |Domain D1 179 | Ro | 180 | | 181 | A | 182 | | 183 +-B------------C-+ 184 / \ 185 / \ 186 / \ 187 Domain D2 / \ Domain D3 188 +-------------D--+ +-----E----------+ 189 | | | | 190 | F | | | 191 | G | | H | 192 | | | | 193 | | | | 194 +-I--------------+ +-J------------K-+ 195 /\ / \ 196 / \ / \ 197 / \ / \ 198 / \ / \ 199 / \ / \ 200 / \ / \ 201 / Domain D4 \ Domain D5 / Domain D6 \ 202 +-L-------------W+ +------P---------+ +-----------T----+ 203 | | | | | | 204 | | | Q | | U | 205 | M O | | S | | | 206 | | | | | V | 207 | N | | R | | | 208 +----------------+ +----------------+ +----------------+ 210 Figure 1: Domain Topology Example 212 The domain tree can be represented as a series of domain sequences: 214 Domain D1, Domain D3, Domain D6 216 Domain D1, Domain D3, Domain D5 218 Domain D1, Domain D2, Domain D4 220 Since destinations in different destination domain will have 221 different domain sequence within the domain tree, it requires 222 following encoding that binds destinations to a particular domain 223 sequence. 225 o Destination M and N: D1-D2-D4 227 o Destination R and S: D1-D3-D5 229 o Destination U and V: D1-D3-D6 231 An extension in P2MP Path Computation request is needed to support 232 this. (Refer Section 4.2) 234 The abstract nodes MAY include (but not limited to) domain subobjects 235 - AS number and IGP Area as described in [RFC7897]. 237 3.2. Explicit inclusion or exclusion of abstract nodes 239 [I-D.ietf-pce-rfc6006bis] describes four possible types of leaves in 240 a P2MP request encoded in P2MP END-POINTS object. 242 o New leaves to add 244 o Old leaves to remove 246 o Old leaves whose path can be modified/reoptimized 248 o Old leaves whose path must be left unchanged 250 [I-D.ietf-pce-rfc6006bis] only allows to encode a list of nodes that 251 have (or have not) the branch node capability by using the Branch 252 Node Capability (BNC) Object. This object apply to all destinations 253 (old and new) in the P2MP tree. 255 For an existing P2MP tree with an overloaded branch node, when adding 256 a set of new leaves, administrator may want to exclude that 257 particular branch node to balance the final P2MP tree. This cannot 258 be achieved via the BNC object but by explicitly excluding a 259 particular node or including a different node, for the P2MP END- 260 POINTS object for new leaves only. 262 Administrator at the Ingress can exert stronger control by providing 263 explicit inclusion or exclusion of any abstract nodes (not limited to 264 specifying nodes with branch node capability) for a group (subset) of 265 destinations and not all destinations. 267 4. Detailed Description 268 4.1. Objective 270 [I-D.ietf-pce-rfc6006bis] and [I-D.ietf-pce-stateful-pce-p2mp] 271 defines Request Message Format and Objects, along with . This section introduce the use of and 273 which are added to the . 275 To allow abstract nodes to be explicitly included or excluded for a 276 subset of destinations (encoded in one object), changes 277 are made as shown below. 279 The abstract node (encoded as subobject in and ) MAY be an 280 absolute hop, IP-Prefix, AS or IGP Area. The subobjects are 281 described in [RFC3209], [RFC3477], [RFC4874] and [RFC7897]. 283 Note that one P2MP Path request can have multiple 284 objects and each P2MP object may have multiple 285 destinations, the , and is applied for all 286 destinations in one such P2MP object. 288 4.2. Request Message Format 290 The format of PCReq message, with [I-D.ietf-pce-stateful-pce-p2mp] as 291 base, is modified as follows: 293 ::= 294 [] 295 297 where: 299 ::= 300 [] 301 [] 302 [] 304 ::=[] 306 ::= 307 308 [] 309 [] 310 [] 311 [] 312 [] 313 [|] 314 [] 316 ::= 317 318 [] 319 [] 320 [][] 321 [] 323 ::=(|)[] 324 ::=[] 326 From [I-D.ietf-pce-rfc6006bis] and [I-D.ietf-pce-stateful-pce-p2mp], 327 usage of is changed to in this document. 330 [I-D.ietf-pce-rfc6006bis] describes Branch Node Capability (BNC) 331 Object which is different from the use of and to specify 332 inclusion/exclusion of abstract nodes for a subset of destinations as 333 described here. 335 4.3. Report Message Format 337 [I-D.ietf-pce-stateful-pce-p2mp] defines a report message format and 338 objects. This document extends the message to allow explicit 339 inclusion and exclusion of abstract nodes for a group of 340 destinations. 342 ::= 343 344 Where: 346 ::= 347 [] 349 ::= [] 350 351 352 [ 353 ] 354 356 Where: 358 ::= 359 [] 360 [] 361 [] 362 [] 363 364 [] 366 ::= 367 [] 368 [] 369 370 [] 372 ::= (|) 373 [] 375 ::= (|) 376 [] 378 is represented by the ERO, SERO object. The 379 consists of the actual computed and signaled 380 values of the and objects defined in 381 [RFC5440]. is represented by the RRO, SERO object. 383 The is extended to add the IRO 384 and XRO object for a group of destinations in the END-POINTS object. 386 4.4. Backward Compatibility 388 A legacy implementation that does not support explicit inclusion or 389 exclusion of abstract nodes for a subset of P2MP destinations will 390 act according to the procedures set out in [RFC5440], that is it will 391 find the P2MP Path Request message out of order with respect to the 392 format specified in [I-D.ietf-pce-rfc6006bis] and 393 [I-D.ietf-pce-stateful-pce-p2mp]. 395 5. IANA Considerations 397 There are no new IANA allocation in this document. 399 6. Security Considerations 401 PCEP security mechanisms as described in [RFC5440], 402 [I-D.ietf-pce-rfc6006bis], [RFC7334] and 403 [I-D.ietf-pce-stateful-pce-p2mp] are applicable for this document. 405 The new explicit inclusion or exclusion of abstract nodes for a 406 subset of P2MP destination defined in this document allow finer and 407 more specific control of the path computed by a PCE. Such control 408 increases the risk if a PCEP message is intercepted, modified, or 409 spoofed because it allows the attacker to exert control over the path 410 that the PCE will compute or to make the path computation impossible. 411 Therefore, the security techniques described in [RFC5440], 412 [I-D.ietf-pce-rfc6006bis], [RFC7334] and 413 [I-D.ietf-pce-stateful-pce-p2mp] are considered more important. 415 Note, however, that the route exclusion mechanisms also provide the 416 operator with the ability to route around vulnerable parts of the 417 network and may be used to increase overall network security. 419 7. Manageability Considerations 421 7.1. Control of Function and Policy 423 Mechanisms defined in this document do not add any new control 424 function/policy requirements in addition to those already listed in 425 [I-D.ietf-pce-rfc6006bis] and [I-D.ietf-pce-stateful-pce-p2mp]. 427 7.2. Information and Data Models 429 Mechanisms defined in this document do not imply any new MIB 430 requirements. 432 7.3. Liveness Detection and Monitoring 434 Mechanisms defined in this document do not imply any new liveness 435 detection and monitoring requirements in addition to those already 436 listed in [I-D.ietf-pce-rfc6006bis] and 437 [I-D.ietf-pce-stateful-pce-p2mp]. 439 7.4. Verify Correct Operations 441 Mechanisms defined in this document do not imply any new operation 442 verification requirements in addition to those already listed in 443 [I-D.ietf-pce-rfc6006bis] and [I-D.ietf-pce-stateful-pce-p2mp]. 445 7.5. Requirements On Other Protocols 447 Mechanisms defined in this document do not imply any requirements on 448 other protocols in addition to those already listed in 449 [I-D.ietf-pce-rfc6006bis] and [I-D.ietf-pce-stateful-pce-p2mp]. 451 7.6. Impact On Network Operations 453 Mechanisms defined in this document do not have any impact on network 454 operations in addition to those already listed in 455 [I-D.ietf-pce-rfc6006bis] and [I-D.ietf-pce-stateful-pce-p2mp]. 457 8. Acknowledgments 459 We would like to thank Pradeep Shastry, Suresh babu, Quintin Zhao, 460 Daniel King and Chen Huaimo for their useful comments and 461 suggestions. 463 9. References 465 9.1. Normative References 467 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 468 Requirement Levels", BCP 14, RFC 2119, 469 DOI 10.17487/RFC2119, March 1997, 470 . 472 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 473 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 474 DOI 10.17487/RFC5440, March 2009, 475 . 477 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 478 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 479 May 2017, . 481 [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path 482 Computation Element Communication Protocol (PCEP) 483 Extensions for Stateful PCE", RFC 8231, 484 DOI 10.17487/RFC8231, September 2017, 485 . 487 [I-D.ietf-pce-rfc6006bis] 488 Zhao, Q., Dhody, D., Palleti, R., and D. King, "Extensions 489 to the Path Computation Element Communication Protocol 490 (PCEP) for Point-to-Multipoint Traffic Engineering Label 491 Switched Paths", draft-ietf-pce-rfc6006bis-04 (work in 492 progress), September 2017. 494 [I-D.ietf-pce-pce-initiated-lsp] 495 Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "PCEP 496 Extensions for PCE-initiated LSP Setup in a Stateful PCE 497 Model", draft-ietf-pce-pce-initiated-lsp-10 (work in 498 progress), June 2017. 500 [I-D.ietf-pce-stateful-pce-p2mp] 501 Palle, U., Dhody, D., Tanaka, Y., and V. Beeram, "Path 502 Computation Element (PCE) Protocol Extensions for Stateful 503 PCE usage for Point-to-Multipoint Traffic Engineering 504 Label Switched Paths", draft-ietf-pce-stateful-pce-p2mp-04 505 (work in progress), July 2017. 507 9.2. Informative References 509 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 510 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 511 Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, 512 . 514 [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links 515 in Resource ReSerVation Protocol - Traffic Engineering 516 (RSVP-TE)", RFC 3477, DOI 10.17487/RFC3477, January 2003, 517 . 519 [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation 520 Element (PCE)-Based Architecture", RFC 4655, 521 DOI 10.17487/RFC4655, August 2006, 522 . 524 [RFC4874] Lee, CY., Farrel, A., and S. De Cnodder, "Exclude Routes - 525 Extension to Resource ReserVation Protocol-Traffic 526 Engineering (RSVP-TE)", RFC 4874, DOI 10.17487/RFC4874, 527 April 2007, . 529 [RFC5862] Yasukawa, S. and A. Farrel, "Path Computation Clients 530 (PCC) - Path Computation Element (PCE) Requirements for 531 Point-to-Multipoint MPLS-TE", RFC 5862, 532 DOI 10.17487/RFC5862, June 2010, 533 . 535 [RFC7334] Zhao, Q., Dhody, D., King, D., Ali, Z., and R. Casellas, 536 "PCE-Based Computation Procedure to Compute Shortest 537 Constrained Point-to-Multipoint (P2MP) Inter-Domain 538 Traffic Engineering Label Switched Paths", RFC 7334, 539 DOI 10.17487/RFC7334, August 2014, 540 . 542 [RFC7897] Dhody, D., Palle, U., and R. Casellas, "Domain Subobjects 543 for the Path Computation Element Communication Protocol 544 (PCEP)", RFC 7897, DOI 10.17487/RFC7897, June 2016, 545 . 547 [RFC8051] Zhang, X., Ed. and I. Minei, Ed., "Applicability of a 548 Stateful Path Computation Element (PCE)", RFC 8051, 549 DOI 10.17487/RFC8051, January 2017, 550 . 552 Authors' Addresses 554 Dhruv Dhody 555 Huawei Technologies 556 Divyashree Techno Park, Whitefield 557 Bangalore, Karnataka 560066 558 India 560 EMail: dhruv.ietf@gmail.com 561 Ramanjaneya Reddy Palleti 562 Huawei Technologies 563 Divyashree Techno Park, Whitefield 564 Bangalore, Karnataka 560066 565 India 567 EMail: ramanjaneya.palleti@huawei.com 569 Udayasree Palle 570 Huawei Technologies 571 Divyashree Techno Park, Whitefield 572 Bangalore, Karnataka 560066 573 India 575 EMail: udayasreereddy@gmail.com 577 Venugopal Reddy Kondreddy 578 Huawei Technologies 579 Divyashree Techno Park, Whitefield 580 Bangalore, Karnataka 560066 581 India 583 EMail: venugopalreddyk@huawei.com