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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 PCE Working Group C. Barth 3 Internet-Draft R. Torvi 4 Intended status: Standards Track Juniper Networks 5 Expires: December 30, 2018 June 28, 2018 7 PCEP Extensions for RSVP-TE Local-Protection with PCE-Stateful 8 draft-cbrt-pce-stateful-local-protection-01 10 Abstract 12 Stateful PCE [RFC8231] can apply global concurrent optimizations to 13 optimize LSP placement. In a deployment where a PCE is used to 14 compute all the paths, it may be beneficial for the local protection 15 paths to also be computed by the PCE. This document defines 16 extensions needed for the setup and management of RSVP-TE protection 17 paths by the PCE. 19 Status of This Memo 21 This Internet-Draft is submitted in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF). Note that other groups may also distribute 26 working documents as Internet-Drafts. The list of current Internet- 27 Drafts is at https://datatracker.ietf.org/drafts/current/. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 This Internet-Draft will expire on December 30, 2018. 36 Copyright Notice 38 Copyright (c) 2018 IETF Trust and the persons identified as the 39 document authors. All rights reserved. 41 This document is subject to BCP 78 and the IETF Trust's Legal 42 Provisions Relating to IETF Documents 43 (https://trustee.ietf.org/license-info) in effect on the date of 44 publication of this document. Please review these documents 45 carefully, as they describe your rights and restrictions with respect 46 to this document. Code Components extracted from this document must 47 include Simplified BSD License text as described in Section 4.e of 48 the Trust Legal Provisions and are provided without warranty as 49 described in the Simplified BSD License. 51 Table of Contents 53 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 54 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 55 3. Architectural Overview . . . . . . . . . . . . . . . . . . . 3 56 3.1. Local Protection Overview . . . . . . . . . . . . . . . . 3 57 4. Extensions for the LSPA object . . . . . . . . . . . . . . . 4 58 4.1. The Preference TLV . . . . . . . . . . . . . . . . . . . 4 59 4.2. The Bypass TLV . . . . . . . . . . . . . . . . . . . . . 5 60 4.3. The LOCALLY-PROTECTED-LSPS TLV . . . . . . . . . . . . . 6 61 5. IANA considerations . . . . . . . . . . . . . . . . . . . . . 8 62 5.1. PCEP-Error Object . . . . . . . . . . . . . . . . . . . . 8 63 5.2. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 8 64 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 65 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 8 66 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 67 8.1. Normative References . . . . . . . . . . . . . . . . . . 9 68 8.2. Informative References . . . . . . . . . . . . . . . . . 9 69 Appendix A. Additional Stuff . . . . . . . . . . . . . . . . . . 10 70 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 72 1. Introduction 74 [RFC5440] describes the Path Computation Element Protocol PCEP. PCEP 75 defines the communication between a Path Computation Client (PCC) and 76 a Path Control Element (PCE), or between PCE and PCE, enabling 77 computation of Multi-protocol Label Switching (MPLS) for Traffic 78 Engineering Label Switched Path (TE LSP) characteristics. 80 Stateful PCE [RFC8231] specifies a set of extensions to PCEP to 81 enable stateful control of paths such as MPLS TE LSPs between and 82 across PCEP sessions in compliance with [RFC4657]. It includes 83 mechanisms to effect LSP state synchronization between PCCs and PCEs 84 and allow delegation of control of LSPs to PCEs. 86 In a network where all LSPs have control delegated to a PCE, the PCE 87 can apply global concurrent optimization to optimize LSP placement. 88 The PCE can also control the timing and sequence of path computation 89 and applying path changes. In a deployment where a PCE is used to 90 compute all the paths, it may be beneficial for the protection paths 91 to also be controlled through the PCE. This document defines 92 extensions needed for the setup and management of protection paths by 93 the PCE. 95 Benefits of stateful synchronization and control of the protection 96 paths include: 98 o Better control over traffic after a failure and more deterministic 99 path computation of protection paths. The PCE can optimize the 100 protection path based on data not available to the PCC, for instance 101 the PCE can make sure the protection path will not violate the delay 102 specified by [I-D.ietf-pce-pcep-service-aware]. 104 o Satisfy more complex constraints and diversity requirements, such 105 as maintaining diverse paths for LSPs as well as their local 106 protection paths. 108 o Given the PCE's global view of network resources, act as a form of 109 LSP admission control into a protection path to ensure links are not 110 overloaded during failure events. 112 o On a PLR with multiple available protection routes, allows the PCE 113 to map LSPs to all available protection routes versus a single best 114 protection route. 116 o Most of the benefits stated in the stateful PCE applicability draft 117 [I-D.ietf-pce-stateful-pce-app-04] apply equally to protection paths. 119 2. Terminology 121 This document uses the following terms defined in [RFC5440] PCC PCE, 122 PCEP Peer. 124 This document uses the following terms defined in [RFC8231] Stateful 125 PCE, Delegation, Delegation Timeout Interval, LSP State Report, LSP 126 Update Request. 128 The message formats in this document are specified using Routing 129 Backus-Naur Format (RBNF) encoding as specified in RFC5511. 131 3. Architectural Overview 133 3.1. Local Protection Overview 135 Local protection refers to the ability to locally route around 136 failure of an LSP. Two types of local protection are possible: 138 (1) 1:1 protection - the protection path protects a single LSP. 140 (2) N:1 protection - the protection path protects multiple LSPs 141 traversing the protected resource. 143 It is assumed that the PCE knows what resources require protection 144 through mechanisms outside the scope of this document. In a PCE 145 controlled deployment, support of 1:1 protection has limited 146 applicability, and can be achieved as a degenerate case of 1:N 147 protection. For this reason, local protection will be discussed only 148 for the N:1 case. 150 Local protection requires the setup of a bypass at the PLR. This 151 bypass can be PCC-initiated and delegated, or PCE-initiated. In 152 either case, the PLR MUST maintain a PCEP session to the PCE. A 153 bypass identifier (the name of the bypass) is required for 154 disambiguation as multiple bypasses are possible at the PLR. There 155 two types Bypass LSPs mappings: 157 (1) Independent Bypass LSP Mapping: In this case Bypass LSP mapping 158 is handled by a local policy on PCC and the PCC reports all mappings 159 to the PCE. In other words, bypass LSP(s) are mapped to any 160 protected LSP(s) that satisfy PCC local policy. 162 (2) Dependent Bypass LSP mapping: Mapping of LSPs to bypass is done 163 through a new TLV, the LOCALLY-PROTECTED-LSPS TLV in the LSP Update 164 message from PCE to PLR. See section Section 4.3. When an LSP 165 requiring protection is set up through the PLR, the PLR checks if it 166 has a mapping to a bypass and only provides protection if such a 167 mapping exists. The status of bypasses and what LSPs are protected 168 by them is communicated to the PCE via LSP Status Report messages. 170 4. Extensions for the LSPA object 172 4.1. The Preference TLV 174 When provisioning a PCC, the PCE can influence primary to bypass LSP 175 association of the PCC using the preference TLV. Bypass LSPs with a 176 higher preference are used first during primary LSP association. 177 Bypass LSPs with identical preferences are used for primary 178 association according to local PCC selection. 180 The format of the IPv4 Preference TLV is shown in the following 181 figure: 183 0 1 2 3 184 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 2 185 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 186 | Type=[TBD] | Length=8 | 187 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 188 | MUST be zero | Preference | 189 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 191 Figure 1: IPv4 Preference TLV format 193 The type of the TLV is [TBD] and it has a fixed length of 8 octets. 194 The value contains the following fields: 196 Preference (8 bits): The value indicates the bypass LSP preference 197 during the primary LSP selection process of the PCC. A lower 198 preference value is preferred to a higher value with a default value 199 of 255. A value of 0 would indicate that the bypass is not to be 200 selected for any primary LSP associations. 202 If the Preference TLV is included, then the LSPA object MUST also 203 carry the SYMBOLIC-PATH-NAME TLV as one of the optional TLVs. 204 Failure to include the mandatory SYMBOLIC-PATH-NAME TLV MUST trigger 205 PCErr of type 6 (Mandatory Object missing) and value TBD (SYMBOLIC- 206 PATH-NAME TLV missing for bypass LSP). 208 4.2. The Bypass TLV 210 The facility backup method creates a bypass tunnel to protect a 211 potential failure point. The bypass tunnel protects a set of LSPs 212 with similar backup constraints [RFC4090]. 214 A PCC can delegate a bypass tunnel to PCE control or a PCE can 215 provision the bypass tunnel via a PCC. The procedures for bypass 216 instantiation rely on the extensions defined in [RFC8281] and will be 217 detailed in a future version of this document. 219 A subscription multiplier can be used to influence the local PCC 220 admission control during primary LSP association. This allows for 221 under subscription or oversubscription policy to be applied to the 222 bandwidth attribute of the bypass LSP. 224 The Bypass TLV carries information about the bypass tunnel. It is 225 included in the LSPA Object in LSP State Report and LSP Update 226 Request messages. 228 The format of the IPv4 Bypass TLV is shown in the following figure: 230 0 1 2 3 231 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 2 232 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 233 | Type=[TBD] | Length=8 | 234 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 235 | MUST be zero | Flags |I|N| 236 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 237 | Bypass IPv4 Address | 238 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 239 | Subscription Multiplier | 240 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 242 Figure 2: IPv4 Bypass TLV format 244 The type of the TLV is [TBD] and it has a fixed length of 8 octets. 245 The value contains the following fields: 247 Flags (16 bit) 249 N (Node Protection - 1 bit): The N flag indicates whether the Bypass 250 is used for node-protection. If the N flag is set to 1, the Bypass 251 is used for node-protection. If the N flag is 0, the Bypass is used 252 for link-protection. 254 I (Local Protection In Use - 1 bit): The I Flag indicates that local 255 repair mechanism is in use. 257 Bypass IPv4 address: The Bypass IPv4 Address is the next-hop address 258 of the protected link in the paths of the protected LSPs. 260 Subscription Multiplier (32 bits): An optional multiplier represented 261 as a floating point number. The value may be used to influence CAC 262 during primary LSP association. For example, a bypass may reserved 263 50M but the PCC may want to admit up to (multiplier * reserved 264 bandwidth) to the bypass LSP. 266 If the Bypass TLV is included, then the LSPA object MUST also carry 267 the SYMBOLIC-PATH-NAME TLV as one of the optional TLVs. Failure to 268 include the mandatory SYMBOLIC-PATH-NAME TLV MUST trigger PCErr of 269 type 6 (Mandatory Object missing) and value TBD (SYMBOLIC-PATH-NAME 270 TLV missing for bypass LSP) 272 4.3. The LOCALLY-PROTECTED-LSPS TLV 274 The IPV4-LOCALLY-PROTECTED-LSPS TLV in the LSPA Object contains a 275 list of LSPs protected by the bypass tunnel. 277 The format of the Locally protected LSPs TLV is shown in the 278 following figure: 280 0 1 2 3 281 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 2 282 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 283 | Type=[TBD] | Length (variable) | 284 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 285 | IPv4 tunnel end point address | 286 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 287 | Flags |R| Tunnel ID | 288 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 289 | Extended Tunnel ID | 290 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 291 | IPv4 Tunnel Sender Address | 292 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 293 | MUST be zero | LSP ID | 294 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 295 // .... // 296 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 297 | IPv4 tunnel end point address | 298 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 299 | Flags |R| Tunnel ID | 300 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 301 | Extended Tunnel ID | 302 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 303 | IPv4 Tunnel Sender Address | 304 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 305 | MUST be zero | LSP ID | 306 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 308 Figure 3: IPv4 Locally protected LSPs TLV format 310 The type of the TLV is [TBD] and it is of variable length.The value 311 contains one or more LSP descriptors including the following fields 312 filled per [RFC3209] 314 IPv4 Tunnel end point address: As defined in [RFC3209], 315 Section 4.6.1.1 317 Flags (16 bit) 319 R(Remove - 1 bit): The R flag indicates that the LSP has been removed 320 from the list of LSPs protected by the bypass tunnel. 322 Tunnel ID: As defined in [RFC3209], Section 4.6.1.1 324 Extended Tunnel ID: As defined in [RFC3209], Section 4.6.2.1 325 IPv4 Tunnel Sender address: As defined in [RFC3209], Section 4.6.2.1 327 LSP ID: As defined in RFC 3209 329 5. IANA considerations 331 5.1. PCEP-Error Object 333 This document defines new Error-Type and Error-Value for the 334 following new error conditions: 336 Error-Type Meaning 6 Mandatory Object missing Error-value=TBD: 337 SYMBOLIC-PATH-NAME TLV missing for a path where the S-bit is set in 338 the LSPA object. Error-value=TBD: SYMBOLIC-PATH-NAME TLV missing for 339 a bypass path. 341 5.2. PCEP TLV Type Indicators 343 This document defines the following new PCEP TLVs: 345 +---------+------------------------+---------------+ 346 | Value # | Meaning | Reference | 347 +---------+------------------------+---------------+ 348 | ??? | Bypass | This Document | 349 | ??? | Weight | This Document | 350 | ??? | LOCALLY-PROTECTED-LSPS | This Document | 351 +---------+------------------------+---------------+ 353 Table 1: New PCEP TLVs 355 6. Security Considerations 357 The same security considerations apply at the PLR as those describe 358 for the head end in PCE Initiated LSPs [RFC8281]. 360 7. Contributors 362 The following people have substantially contributed to the editing of 363 this document: 365 Harish Sitaraman, Juniper Networks, hsitaraman@juniper.net 367 Vishnu Pavan Beeram, Juniper Networks, vbeeram@juniper.net 369 Chandrasekar Ramachandran, Juniper Networks, csekar@juniper.net 371 Ambrose Kwong, Juniper Networks, akwong@juniper.net 372 Phil Bedard, bedard.phil@gmail.com 374 8. References 376 8.1. Normative References 378 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 379 Requirement Levels", BCP 14, RFC 2119, 380 DOI 10.17487/RFC2119, March 1997, 381 . 383 [RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S. 384 Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 385 Functional Specification", September 1997. 387 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 388 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 389 Tunnels", December 2001. 391 [RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute 392 Extensions to RSVP-TE for LSP Tunnels", May 2005. 394 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 395 IANA Considerations Section in RFCs", May 2008. 397 [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element 398 (PCE) Communication Protocol (PCEP)", March 2009. 400 [RFC8231] Crabbe, E., Medved, J., Minie, I., and R. Verga, "PCEP 401 Extensions for Stateful PCE", 2015. 403 [RFC8281] Crabbe, E., Sivabalan, S., and R. Verga, "PCEP Extensions 404 for PCE-initiated LSP Setup in a Stateful PCE Model", 405 2014. 407 8.2. Informative References 409 [I-D.narten-iana-considerations-rfc2434bis] 410 Narten, T. and H. Alvestrand, "Guidelines for Writing an 411 IANA Considerations Section in RFCs", draft-narten-iana- 412 considerations-rfc2434bis-09 (work in progress), March 413 2008. 415 [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, 416 DOI 10.17487/RFC2629, June 1999, 417 . 419 [RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC 420 Text on Security Considerations", BCP 72, RFC 3552, 421 DOI 10.17487/RFC3552, July 2003, 422 . 424 [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation 425 Element (PCE)-Based Architecture", August 2006. 427 [RFC4657] Ash, J. and J. Le Roux, "Path Computation Element (PCE) 428 Communication Protocol Generic Requirements", September 429 2006. 431 [RFC5394] Bryskin, I., Papadimitriou, D., Berger, L., and J. Ash, 432 "Policy-Enabled Path Computation Framework", December 433 2008. 435 [RFC5557] Lee, Y., Le Roux, JL., King, D., and E. Oki, "Path 436 Computation Element Communication Protocol (PCEP) 437 Requirements and Protocol Extensions in Support of Global 438 Concurrent Optimization", July 2009. 440 Appendix A. Additional Stuff 442 This becomes an Appendix. 444 Authors' Addresses 446 Colby Barth 447 Juniper Networks 448 Sunnyvale, CA 449 USA 451 Email: cbarth@juniper.net 453 Raveendra Torvi 454 Juniper Networks 455 Sunnyvale, CA 456 USA 458 Email: rtorvi@juniper.net