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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 PCE Working Group D. Dhody 3 Internet-Draft S. Peng 4 Intended status: Experimental Huawei Technologies 5 Expires: May 6, 2021 Y. Lee 6 Samsung Electronics 7 D. Ceccarelli 8 Ericsson 9 A. Wang 10 China Telecom 11 November 2, 2020 13 PCEP extensions for Distribution of Link-State and TE Information 14 draft-dhodylee-pce-pcep-ls-18 16 Abstract 18 In order to compute and provide optimal paths, a Path Computation 19 Elements (PCEs) require an accurate and timely Traffic Engineering 20 Database (TED). Traditionally, this TED has been obtained from a 21 link state (LS) routing protocol supporting the traffic engineering 22 extensions. 24 This document extends the Path Computation Element Communication 25 Protocol (PCEP) with Link-State and TE Information. 27 Requirements Language 29 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 30 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 31 "OPTIONAL" in this document are to be interpreted as described in BCP 32 14 [RFC2119] [RFC8174] when, and only when, they appear in all 33 capitals, as shown here. 35 Status of This Memo 37 This Internet-Draft is submitted in full conformance with the 38 provisions of BCP 78 and BCP 79. 40 Internet-Drafts are working documents of the Internet Engineering 41 Task Force (IETF). Note that other groups may also distribute 42 working documents as Internet-Drafts. The list of current Internet- 43 Drafts is at https://datatracker.ietf.org/drafts/current/. 45 Internet-Drafts are draft documents valid for a maximum of six months 46 and may be updated, replaced, or obsoleted by other documents at any 47 time. It is inappropriate to use Internet-Drafts as reference 48 material or to cite them other than as "work in progress." 49 This Internet-Draft will expire on May 6, 2021. 51 Copyright Notice 53 Copyright (c) 2020 IETF Trust and the persons identified as the 54 document authors. All rights reserved. 56 This document is subject to BCP 78 and the IETF Trust's Legal 57 Provisions Relating to IETF Documents 58 (https://trustee.ietf.org/license-info) in effect on the date of 59 publication of this document. Please review these documents 60 carefully, as they describe your rights and restrictions with respect 61 to this document. Code Components extracted from this document must 62 include Simplified BSD License text as described in Section 4.e of 63 the Trust Legal Provisions and are provided without warranty as 64 described in the Simplified BSD License. 66 Table of Contents 68 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 69 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 70 3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 5 71 4. Requirements for PCEP extensions . . . . . . . . . . . . . . 6 72 5. New Functions to distribute link-state (and TE) via PCEP . . 7 73 6. Overview of Extensions to PCEP . . . . . . . . . . . . . . . 7 74 6.1. New Messages . . . . . . . . . . . . . . . . . . . . . . 7 75 6.2. Capability Advertisement . . . . . . . . . . . . . . . . 8 76 6.3. Initial Link-State (and TE) Synchronization . . . . . . . 8 77 6.3.1. Optimizations for LS Synchronization . . . . . . . . 11 78 6.4. LS Report . . . . . . . . . . . . . . . . . . . . . . . . 11 79 7. Transport . . . . . . . . . . . . . . . . . . . . . . . . . . 11 80 8. PCEP Messages . . . . . . . . . . . . . . . . . . . . . . . . 12 81 8.1. LS Report Message . . . . . . . . . . . . . . . . . . . . 12 82 8.2. The PCErr Message . . . . . . . . . . . . . . . . . . . . 12 83 9. Objects and TLV . . . . . . . . . . . . . . . . . . . . . . . 13 84 9.1. TLV Format . . . . . . . . . . . . . . . . . . . . . . . 13 85 9.2. Open Object . . . . . . . . . . . . . . . . . . . . . . . 13 86 9.2.1. LS Capability TLV . . . . . . . . . . . . . . . . . . 13 87 9.3. LS Object . . . . . . . . . . . . . . . . . . . . . . . . 14 88 9.3.1. Routing Universe TLV . . . . . . . . . . . . . . . . 16 89 9.3.2. Route Distinguisher TLV . . . . . . . . . . . . . . . 17 90 9.3.3. Virtual Network TLV . . . . . . . . . . . . . . . . . 17 91 9.3.4. Local Node Descriptors TLV . . . . . . . . . . . . . 17 92 9.3.5. Remote Node Descriptors TLV . . . . . . . . . . . . . 18 93 9.3.6. Node Descriptors Sub-TLVs . . . . . . . . . . . . . . 19 94 9.3.7. Link Descriptors TLV . . . . . . . . . . . . . . . . 20 95 9.3.8. Prefix Descriptors TLV . . . . . . . . . . . . . . . 20 96 9.3.9. PCEP-LS Attributes . . . . . . . . . . . . . . . . . 21 97 9.3.9.1. Node Attributes TLV . . . . . . . . . . . . . . . 21 98 9.3.9.2. Link Attributes TLV . . . . . . . . . . . . . . . 21 99 9.3.9.3. Prefix Attributes TLV . . . . . . . . . . . . . . 22 100 9.3.10. Removal of an Attribute . . . . . . . . . . . . . . . 22 101 10. Other Considerations . . . . . . . . . . . . . . . . . . . . 23 102 10.1. Inter-AS Links . . . . . . . . . . . . . . . . . . . . . 23 103 11. Security Considerations . . . . . . . . . . . . . . . . . . . 23 104 12. Manageability Considerations . . . . . . . . . . . . . . . . 23 105 12.1. Control of Function and Policy . . . . . . . . . . . . . 23 106 12.2. Information and Data Models . . . . . . . . . . . . . . 24 107 12.3. Liveness Detection and Monitoring . . . . . . . . . . . 24 108 12.4. Verify Correct Operations . . . . . . . . . . . . . . . 24 109 12.5. Requirements On Other Protocols . . . . . . . . . . . . 25 110 12.6. Impact On Network Operations . . . . . . . . . . . . . . 25 111 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 112 13.1. PCEP Messages . . . . . . . . . . . . . . . . . . . . . 25 113 13.2. PCEP Objects . . . . . . . . . . . . . . . . . . . . . . 25 114 13.3. LS Object . . . . . . . . . . . . . . . . . . . . . . . 25 115 13.4. PCEP-Error Object . . . . . . . . . . . . . . . . . . . 26 116 13.5. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 27 117 13.6. PCEP-LS Sub-TLV Type Indicators . . . . . . . . . . . . 27 118 14. TLV Code Points Summary . . . . . . . . . . . . . . . . . . . 28 119 15. Implementation Status . . . . . . . . . . . . . . . . . . . . 29 120 15.1. Hierarchical Transport PCE controllers . . . . . . . . . 29 121 15.2. ONOS-based Controller (MDSC and PNC) . . . . . . . . . . 30 122 16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 30 123 17. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 124 17.1. Normative References . . . . . . . . . . . . . . . . . . 30 125 17.2. Informative References . . . . . . . . . . . . . . . . . 31 126 Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 35 127 A.1. All Nodes . . . . . . . . . . . . . . . . . . . . . . . . 35 128 A.2. Designated Node . . . . . . . . . . . . . . . . . . . . . 36 129 A.3. Between PCEs . . . . . . . . . . . . . . . . . . . . . . 36 130 Appendix B. Contributor Addresses . . . . . . . . . . . . . . . 38 131 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38 133 1. Introduction 135 In Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS), 136 a Traffic Engineering Database (TED) is used in computing paths for 137 connection-oriented packet services and for circuits. The TED 138 contains all relevant information that a Path Computation Element 139 (PCE) needs to perform its computations. It is important that the 140 TED be 'complete and accurate' each time the PCE performs a path 141 computation. 143 In MPLS and GMPLS, interior gateway routing protocols (Interior 144 Gateway Protocol (IGPs)) have been used to create and maintain a copy 145 of the TED at each node running the IGP. One of the benefits of the 146 PCE architecture [RFC4655] is the use of computationally more 147 sophisticated path computation algorithms and the realization that 148 these may need enhanced processing power (not necessarily available 149 at each node). 151 Section 4.3 of [RFC4655] describes the potential load of the TED on a 152 network node and proposes an architecture where the TED is maintained 153 by the PCE rather than the network nodes. However, it does not 154 describe how a PCE would obtain the information needed to populate 155 its TED. PCE may construct its TED by participating in the IGP 156 ([RFC3630] and [RFC5305] for MPLS-TE; [RFC4203] and [RFC5307] for 157 GMPLS). An alternative mechanism is offered by BGP-LS 158 [I-D.ietf-idr-rfc7752bis] . 160 [RFC8231] describes a set of extensions to PCEP to provide stateful 161 control. A stateful PCE has access to not only the information 162 carried by the network's IGP, but also the set of active paths and 163 their reserved resources for its computations. Path Computation 164 Client (PCC) can delegate the rights to modify the LSP parameters to 165 an Active Stateful PCE. This requires PCE to quickly be updated on 166 any changes in the topology/TED, so that PCE can meet the need for 167 updating LSPs effectively and in a timely manner. The fastest way 168 for a PCE to be updated on TED changes is via a direct session with 169 each network node and with an incremental update from each network 170 node with only the attributes that gets modified. 172 [RFC8281] describes the setup, maintenance, and teardown of PCE- 173 initiated LSPs under the stateful PCE model, without the need for 174 local configuration on the PCC, thus allowing for a dynamic network 175 that is centrally controlled and deployed. This model requires 176 timely topology and TED update at the PCE. 178 [RFC5440] describes the specifications for the Path Computation 179 Element Communication Protocol (PCEP). PCEP specifies the 180 communication between a PCC and a PCE, or between two PCEs based on 181 the PCE architecture [RFC4655]. 183 This document describes a mechanism by which link-state and TE 184 information can be collected from networks and shared with PCE using 185 the PCEP itself. This is achieved using a new PCEP message format. 186 The mechanism is applicable to physical and virtual links as well as 187 further subjected to various policies. 189 A network node maintains one or more databases for storing link-state 190 and TE information about nodes and links in any given area. Link 191 attributes stored in these databases include: local/remote IP 192 addresses, local/remote interface identifiers, link metric, and TE 193 metric, link bandwidth, reservable bandwidth, per CoS class 194 reservation state, preemption, and Shared Risk Link Groups (SRLG). 195 The node's PCEP process can retrieve topology from these databases 196 and distribute it to a PCE, either directly or via another PCEP 197 Speaker, using the encoding specified in this document. 199 Further [RFC6805] describes Hierarchical-PCE architecture, where a 200 parent PCE maintains a domain topology map. To build this domain 201 topology map, the child PCE can carry the border nodes and inter- 202 domain link information to the parent PCE using the mechanism 203 described in this document. Further as described in [RFC8637], the 204 child PCE can also transport abstract Link-State and TE information 205 from child PCE to a Parent PCE using the mechanism described in this 206 document to build an abstract topology at the parent PCE. 208 [RFC8231] describe LSP state synchronization between PCCs and PCEs in 209 case of stateful PCE. This document does not make any change to the 210 LSP state synchronization process. The mechanism described in this 211 document are on top of the existing LSP state synchronization. 213 2. Terminology 215 The terminology is as per [RFC4655] and [RFC5440]. 217 3. Applicability 219 The mechanism specified in this draft is applicable to deployments: 221 o Where there is no IGP or BGP-LS running in the network. 223 o Where there is no IGP or BGP-LS running at the PCE to learn link- 224 state and TE information. 226 o Where there is IGP or BGP-LS running but with a need for a faster 227 and direct TE and link-state population and convergence at the 228 PCE. 230 * A PCE may receive partial information (say basic TE, link- 231 state) from IGP and other information (optical and impairment) 232 from PCEP. 234 * A PCE may receive an incremental update (as opposed to the full 235 (entire) information of the node/link). 237 * A PCE may receive full information from both existing 238 mechanisms (IGP or BGP-LS) and PCEP. 240 o Where there is a need for transporting (abstract) Link-State and 241 TE information from child PCE to a Parent PCE in H-PCE [RFC6805]; 242 as well as for Provisioning Network Controller (PNC) to Multi- 243 Domain Service Coordinator (MDSC) in Abstraction and Control of TE 244 Networks (ACTN) [RFC8453]. 246 o Where there is an existing PCEP session between all the nodes and 247 the PCE-based central controller (PCECC) [RFC8283], and the 248 operator would like to use PCEP as direct southbound interface to 249 all the nodes in the network. This enables the operator to use 250 PCEP as a single direct protocol between the controller and all 251 the nodes in the network. In this mode, all nodes send only the 252 local information. 254 Based on the local policy and deployment scenario, a PCC chooses to 255 send only local information or both local and remote learned 256 information. How a PCE manages the link-state (and TE) information 257 is implementation specific and thus out of the scope of this 258 document. 260 The prefix information in PCEP-LS can also help in determining the 261 domain of the tunnel destination in the H-PCE (and ACTN) scenario. 262 Section 4.5 of [RFC6805] describe various mechanisms and procedures 263 that might be used, PCEP-LS provides a simple mechanism to exchange 264 this information within PCEP. 266 [RFC8453] defines three types of topology abstraction - (1) Native/ 267 White Topology; (2) Black Topology; and (3) Grey Topology. Based on 268 the local policy, the PNC (or child PCE) would share the domain 269 topology to the MDSC (or Parent PCE) based on the abstraction type. 270 The protocol extensions defined in this document can carry any type 271 of topology abstraction. 273 4. Requirements for PCEP extensions 275 Following key requirements associated with link-state (and TE) 276 distribution are identified for PCEP: 278 1. The PCEP speaker supporting this draft MUST have a mechanism to 279 advertise the Link-State (and TE) distribution capability. 281 2. PCC supporting this draft MUST have the capability to report the 282 link-state (and TE) information to the PCE. This MUST include 283 self originated (local) information and also allow remote 284 information learned via routing protocols. PCC MUST be capable 285 to do the initial bulk sync at the time of session initialization 286 as well as changes after. 288 3. A PCE MAY learn link-state (and TE) from PCEP as well as from 289 existing mechanisms like IGP/BGP-LS. PCEP extensions MUST have a 290 mechanism to link the information learned via other means. There 291 MUST NOT be any changes to the existing link-state (and TE) 292 population mechanism via IGP/BGP-LS. PCEP extension SHOULD keep 293 the properties in a protocol (IGP or BGP-LS) neutral way, such 294 that an implementation may not need to know about any OSPF or IS- 295 IS or BGP protocol specifics. 297 4. It SHOULD be possible to encode only the changes in link-state 298 (and TE) properties (after the initial sync) in PCEP messages. 299 This leads to faster convergence. 301 5. The same mechanism SHOULD be used for both MPLS TE as well as 302 GMPLS, optical, and impairment aware properties. 304 6. The same mechanism SHOULD be used for PCE to PCE Link-state (and 305 TE) synchronization. 307 5. New Functions to distribute link-state (and TE) via PCEP 309 Several new functions are required in PCEP to support distribution of 310 link-state (and TE) information. A function can be initiated either 311 from a PCC towards a PCE (C-E) or from a PCE towards a PCC (E-C). 312 The new functions are: 314 o Capability advertisement (E-C,C-E): both the PCC and the PCE MUST 315 announce during PCEP session establishment that they support PCEP 316 extensions for distribution of link-state (and TE) information 317 defined in this document. 319 o Link-State (and TE) synchronization (C-E): after the session 320 between the PCC and a PCE is initialized, the PCE must learn Link- 321 State (and TE) information before it can perform path 322 computations. In the case of stateful PCE it is RECOMMENDED that 323 this operation be done before LSP state synchronization. 325 o Link-State (and TE) Report (C-E): a PCC sends an LS (and TE) 326 report to a PCE whenever the Link-State and TE information 327 changes. 329 6. Overview of Extensions to PCEP 331 6.1. New Messages 333 In this document, we define a new PCEP message called LS Report 334 (LSRpt), a PCEP message sent by a PCC to a PCE to report link-state 335 (and TE) information. Each LS Report in an LSRpt message can contain 336 the node or link properties. A unique PCEP specific LS identifier 337 (LS-ID) is also carried in the message to identify a node or link and 338 that remains constant for the lifetime of a PCEP session. This 339 identifier on its own is sufficient when no IGP or BGP-LS running in 340 the network for PCE to learn link-state (and TE) information. In 341 case PCE learns some information from PCEP and some from the existing 342 mechanism, the PCC SHOULD include the mapping of IGP or BGP-LS 343 identifier to map the information populated via PCEP with IGP/BGP-LS. 344 See Section 8.1 for details. 346 6.2. Capability Advertisement 348 During PCEP Initialization Phase, PCEP Speakers (PCE or PCC) 349 advertise their support of LS (and TE) distribution via PCEP 350 extensions. A PCEP Speaker includes the "LS Capability" TLV, 351 described in Section 9.2.1, in the OPEN Object to advertise its 352 support for PCEP-LS extensions. The presence of the LS Capability 353 TLV in PCC's OPEN Object indicates that the PCC is willing to send LS 354 Reports with local link-state (and TE) information. The presence of 355 the LS Capability TLV in PCE's Open message indicates that the PCE is 356 interested in receiving LS Reports with local link-state (and TE) 357 information. 359 The PCEP extensions for LS (and TE) distribution MUST NOT be used if 360 one or both PCEP Speakers have not included the LS Capability TLV in 361 their respective OPEN message. If the PCE that supports the 362 extensions of this draft but did not advertise this capability, then 363 upon receipt of an LSRpt message from the PCC, it SHOULD generate a 364 PCErr with error-type 19 (Invalid Operation), error-value TBD1 365 (Attempted LS Report if LS capability was not advertised) and it will 366 terminate the PCEP session. 368 The LS reports sent by PCC MAY carry the remote link-state (and TE) 369 information learned via existing means like IGP and BGP-LS only if 370 both PCEP Speakers set the R (remote) Flag in the "LS Capability" TLV 371 to 'Remote Allowed (R Flag = 1)'. If this is not the case and LS 372 reports carry remote link-state (and TE) information, then a PCErr 373 with error-type 19 (Invalid Operation) and error-value TBD1 374 (Attempted LS Report if LS remote capability was not advertised) and 375 it will terminate the PCEP session. 377 6.3. Initial Link-State (and TE) Synchronization 379 The purpose of LS Synchronization is to provide a checkpoint-in-time 380 state replica of a PCC's link-state (and TE) database in a PCE. 381 State Synchronization is performed immediately after the 382 Initialization phase (see [RFC5440]). In case of stateful PCE 383 ([RFC8231]) it is RECOMMENDED that the LS synchronization should be 384 done before LSP state synchronization. 386 During LS Synchronization, a PCC first takes a snapshot of the state 387 of its database, then sends the snapshot to a PCE in a sequence of LS 388 Reports. Each LS Report sent during LS Synchronization has the SYNC 389 Flag in the LS Object set to 1. The end of synchronization marker is 390 an LSRpt message with the SYNC Flag set to 0 for an LS Object with 391 LS-ID equal to the reserved value 0. If the PCC has no link-state to 392 synchronize, it will only send the end of synchronization marker. 394 Either the PCE or the PCC MAY terminate the session using the PCEP 395 session termination procedures during the synchronization phase. If 396 the session is terminated, the PCE MUST clean up the state it 397 received from this PCC. The session re-establishment MUST be re- 398 attempted per the procedures defined in [RFC5440], including the use 399 of a back-off timer. 401 If the PCC encounters a problem which prevents it from completing the 402 LS synchronization, it MUST send a PCErr message with error-type TBD2 403 (LS Synchronization Error) and error-value 2 (indicating an internal 404 PCC error) to the PCE and terminate the session. 406 The PCE does not send positive acknowledgments for properly received 407 LS synchronization messages. It MUST respond with a PCErr message 408 with error-type TBD2 (LS Synchronization Error) and error-value 1 409 (indicating an error in processing the LSRpt) if it encounters a 410 problem with the LS Report it received from the PCC and it MUST 411 terminate the session. 413 The LS reports can carry local as well as remote link-state (and TE) 414 information depending on the R flag in LS capability TLV. 416 The successful LS Synchronization sequence is shown in Figure 1. 418 +-+-+ +-+-+ 419 |PCC| |PCE| 420 +-+-+ +-+-+ 421 | | 422 |-----LSRpt, SYNC=1----->| (Sync start) 423 | | 424 |-----LSRpt, SYNC=1----->| 425 | . | 426 | . | 427 | . | 428 |-----LSRpt, SYNC=1----->| 429 | . | 430 | . | 431 | . | 432 | | 433 |-----LSRpt, SYNC=0----->| (End of sync marker 434 | | LS Report 435 | | for LS-ID=0) 436 | | (Sync done) 438 Figure 1: Successful LS synchronization 440 The sequence where the PCE fails during the LS Synchronization phase 441 is shown in Figure 2. 443 +-+-+ +-+-+ 444 |PCC| |PCE| 445 +-+-+ +-+-+ 446 | | 447 |-----LSRpt, SYNC=1----->| 448 | | 449 |-----LSRpt, SYNC=1----->| 450 | . | 451 | . | 452 | . | 453 |-----LSRpt, SYNC=1----->| 454 | | 455 |---LSRpt,SYNC=1 | 456 | \ ,-PCErr---| 457 | \ / | 458 | \/ | 459 | /\ | 460 | / `-------->| (Ignored) 461 |<--------` | 463 Figure 2: Failed LS synchronization (PCE failure) 465 The sequence where the PCC fails during the LS Synchronization phase 466 is shown in Figure 3. 468 +-+-+ +-+-+ 469 |PCC| |PCE| 470 +-+-+ +-+-+ 471 | | 472 |-----LSRpt, SYNC=1----->| 473 | | 474 |-----LSRpt, SYNC=1----->| 475 | . | 476 | . | 477 | . | 478 |-------- PCErr--------->| 479 | | 481 Figure 3: Failed LS synchronization (PCC failure) 483 6.3.1. Optimizations for LS Synchronization 485 These optimizations are described in 486 [I-D.kondreddy-pce-pcep-ls-sync-optimizations]. 488 6.4. LS Report 490 The PCC MUST report any changes in the link-state (and TE) 491 information to the PCE by sending an LS Report carried on an LSRpt 492 message to the PCE. Each node and Link would be uniquely identified 493 by a PCEP LS identifier (LS-ID). The LS reports may carry local as 494 well as remote link-state (and TE) information depending on the R 495 flag in LS capability TLV. In case the R flag is set, it MAY also 496 include the mapping of IGP or BGP-LS identifier to map the 497 information populated via PCEP with IGP/BGP-LS identifiers. 499 More details about the LSRpt message are in Section 8.1. 501 7. Transport 503 A permanent PCEP session (section 4.2.8 of [RFC5440]) MUST be 504 established between a PCE and PCC supporting link-state (and TE) 505 distribution via PCEP. In the case of session failure, session re- 506 establishment is re-attempted as per the procedures defined in 507 [RFC5440]. 509 8. PCEP Messages 511 As defined in [RFC5440], a PCEP message consists of a common header 512 followed by a variable-length body made of a set of objects that can 513 be either mandatory or optional. An object is said to be mandatory 514 in a PCEP message when the object must be included for the message to 515 be considered valid. For each PCEP message type, a set of rules is 516 defined that specify the set of objects that the message can carry. 517 An implementation MUST form the PCEP messages using the object 518 ordering specified in this document. 520 8.1. LS Report Message 522 A PCEP LS Report message (also referred to as LSRpt message) is a 523 PCEP message sent by a PCC to a PCE to report the link-state (and TE) 524 information. An LSRpt message can carry more than one LS Reports (LS 525 object). The Message-Type field of the PCEP common header for the 526 LSRpt message is set to [TBD3]. 528 The format of the LSRpt message is as follows: 530 ::= 531 532 Where: 534 ::= [] 536 The LS object is a mandatory object which carries LS information of a 537 node/prefix or a link. Each LS object has a unique LS-ID as 538 described in Section 9.3. If the LS object is missing, the receiving 539 PCE MUST send a PCErr message with Error-type=6 (Mandatory Object 540 missing) and Error-value=[TBD4] (LS object missing). 542 A PCE may choose to implement a limit on the LS information a single 543 PCC can populate. If an LSRpt is received that causes the PCE to 544 exceed this limit, it MUST send a PCErr message with error-type 19 545 (invalid operation) and error-value 4 (indicating resource limit 546 exceeded) in response to the LSRpt message triggering this condition 547 and SHOULD terminate the session. 549 8.2. The PCErr Message 551 If a PCEP speaker has advertised the LS capability on the PCEP 552 session, the PCErr message MAY include the LS object. If the error 553 reported is the result of an LS report, then the LS-ID number MUST be 554 the one from the LSRpt that triggered the error. 556 The format of a PCErr message from [RFC5440] is extended as follows: 558 ::= 559 ( [] ) | 560 [] 562 ::=[] 564 ::=[ | ] 565 567 ::=[] 569 ::=[] 571 ::=[] 573 9. Objects and TLV 575 The PCEP objects defined in this document are compliant with the PCEP 576 object format defined in [RFC5440]. The P flag and the I flag of the 577 PCEP objects defined in this document MUST always be set to 0 on 578 transmission and MUST be ignored on receipt since these flags are 579 exclusively related to path computation requests. 581 9.1. TLV Format 583 The TLV and the sub-TLV format (and padding) in this document, is as 584 per section 7.1 of [RFC5440]. 586 9.2. Open Object 588 This document defines a new optional TLV for use in the OPEN Object. 590 9.2.1. LS Capability TLV 592 The LS-CAPABILITY TLV is an optional TLV for use in the OPEN Object 593 for link-state (and TE) distribution via PCEP capability 594 advertisement. Its format is shown in the following figure: 596 0 1 2 3 597 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 1 598 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 599 | Type=[TBD5] | Length=4 | 600 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 601 | Flags |R| 602 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 603 The type of the TLV is [TBD5] and it has a fixed length of 4 octets. 605 The value comprises a single field - Flags (32 bits): 607 o R (remote allowed - 1 bit): if set to 1 by a PCC, the R Flag 608 indicates that the PCC allows reporting of remote LS information 609 learned via other means like IGP and BGP-LS; if set to 1 by a PCE, 610 the R Flag indicates that the PCE is capable of receiving remote 611 LS information (from the PCC point of view). The R Flag must be 612 advertised by both PCC and PCE for LSRpt messages to report remote 613 as well as local LS information on a PCEP session. The TLVs 614 related to IGP/BGP-LS identifier MUST be encoded when both PCEP 615 speakers have the R Flag set. 617 Unassigned bits are considered reserved. They MUST be set to 0 on 618 transmission and MUST be ignored on receipt. 620 Advertisement of the LS capability implies support of local link- 621 state (and TE) distribution, as well as the objects, TLVs and 622 procedures defined in this document. 624 9.3. LS Object 626 The LS (link-state) object MUST be carried within LSRpt messages and 627 MAY be carried within PCErr messages. The LS object contains a set 628 of fields used to specify the target node or link. It also contains 629 a flag indicating to a PCE that the LS synchronization is in 630 progress. The TLVs used with the LS object correlate with the IGP/ 631 BGP-LS encodings. 633 LS Object-Class is TBD6. 635 Four Object-Type values are defined for the LS object so far: 637 o LS Node: LS Object-Type is 1. 639 o LS Link: LS Object-Type is 2. 641 o LS IPv4 Topology Prefix: LS Object-Type is 3. 643 o LS IPv6 Topology Prefix: LS Object-Type is 4. 645 The format of all types of LS object is as follows: 647 0 1 2 3 648 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 1 649 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 650 | Protocol-ID | Flag |R|S| 651 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 652 | LS-ID | 653 | | 654 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 655 // TLVs // 656 | | 657 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 659 Protocol-ID (8-bit): The field provides the source information. The 660 protocol could be an IGP, BGP-LS, or an abstraction algorithm. In 661 case PCC only provides local information of the PCC, it MUST use 662 Protocol-ID as Direct. The following values are defined (some of the 663 initial values are the same as [I-D.ietf-idr-rfc7752bis]): 665 +-------------+----------------------------------+ 666 | Protocol-ID | Source protocol | 667 +-------------+----------------------------------+ 668 | 1 | IS-IS Level 1 | 669 | 2 | IS-IS Level 2 | 670 | 3 | OSPFv2 | 671 | 4 | Direct | 672 | 5 | Static configuration | 673 | 6 | OSPFv3 | 674 | 7 | BGP | 675 | 8 | RSVP-TE | 676 | 9 | Segment Routing | 677 | 10 | PCEP | 678 | 11 | Abstraction | 679 +-------------+----------------------------------+ 681 Flags (24-bit): 683 o S (SYNC - 1 bit): the S Flag MUST be set to 1 on each LSRpt sent 684 from a PCC during LS Synchronization. The S Flag MUST be set to 0 685 in other LSRpt messages sent from the PCC. 687 o R (Remove - 1 bit): On LSRpt messages, the R Flag indicates that 688 the node/link/prefix has been removed from the PCC and the PCE 689 SHOULD remove from its database. Upon receiving an LS Report with 690 the R Flag set to 1, the PCE SHOULD remove all state for the 691 node/link/prefix identified by the LS Identifiers from its 692 database. 694 LS-ID(64-bit): A PCEP-specific identifier for the node, link, or 695 prefix information. A PCC creates a unique LS-ID for each node/link/ 696 prefix that is constant for the lifetime of a PCEP session. The PCC 697 will advertise the same LS-ID on all PCEP sessions it maintains at a 698 given time. All subsequent PCEP messages then address the node/link/ 699 prefix by the LS-ID. The values of 0 and 0xFFFFFFFFFFFFFFFF are 700 reserved. 702 Unassigned bits are considered reserved. They MUST be set to 0 on 703 transmission and MUST be ignored on receipt. 705 TLVs that may be included in the LS Object are described in the 706 following sections. 708 9.3.1. Routing Universe TLV 710 In the case of remote link-state (and TE) population when existing 711 IGP/BGP-LS are also used, OSPF and IS-IS may run multiple routing 712 protocol instances over the same link as described in 713 [I-D.ietf-idr-rfc7752bis]. See [RFC8202] and [RFC6549] for more 714 information. These instances define an independent "routing 715 universe". The 64-bit 'Identifier' field is used to identify the 716 "routing universe" where the LS object belongs. The LS objects 717 representing IGP objects (nodes or links or prefix) from the same 718 routing universe MUST have the same 'Identifier' value; LS objects 719 with different 'Identifier' values MUST be considered to be from 720 different routing universes. 722 The format of the optional ROUTING-UNIVERSE TLV is shown in the 723 following figure: 725 0 1 2 3 726 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 1 727 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 728 | Type=[TBD7] | Length=8 | 729 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 730 | Identifier | 731 | | 732 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 734 The below table lists the 'Identifier' values that are defined as 735 well-known in this draft (same as [I-D.ietf-idr-rfc7752bis]). 737 +------------+-----------------------------------+ 738 | Identifier | Routing Universe | 739 +------------+-----------------------------------+ 740 | 0 | Default Layer 3 Routing topology | 741 +------------+-----------------------------------+ 743 If this TLV is not present the default value 0 is assumed. 745 9.3.2. Route Distinguisher TLV 747 To allow identification of VPN link, node, and prefix information in 748 PCEP-LS, a Route Distinguisher (RD) [RFC4364] is used. The LS 749 objects from the same VPN MUST have the same RD; LS objects with 750 different RD values MUST be considered to be from different VPNs. 752 The ROUTE-DISTINGUISHER TLV is defined in 753 [I-D.ietf-pce-pcep-flowspec] as a Flow Specification TLVs with a 754 seperate registry. This document also adds the ROUTE-DISTINGUISHER 755 TLV with TBD15 in the PCEP TLV registry to be used inside the LS 756 object. 758 9.3.3. Virtual Network TLV 760 To realize ACTN, the MDSC needs to build a multi-domain topology. 761 This topology is best served if this is an abstracted view of the 762 underlying network resources of each domain. It is also important to 763 provide a customer view of the network slice for each customer. 764 There is a need to control the level of abstraction based on the 765 deployment scenario and business relationship between the 766 controllers. 768 Virtual service coordination function in ACTN incorporates customer 769 service-related knowledge into the virtual network operations in 770 order to seamlessly operate virtual networks while meeting customer's 771 service requirements. [I-D.ietf-teas-actn-requirements] describes 772 various VN operations initiated by a customer/application. In this 773 context, there is a need for associating the abstracted link-state 774 and TE topology with a VN "construct" to facilitate VN operations in 775 PCE architecture. 777 VIRTUAL-NETWORK-TLV as per [I-D.ietf-pce-vn-association] can be 778 included in LS object to identify the link, node, and prefix 779 information belongs to a particular VN. 781 9.3.4. Local Node Descriptors TLV 783 As described in [I-D.ietf-idr-rfc7752bis], each link is anchored by a 784 pair of Router-IDs that are used by the underlying IGP, namely, 785 48-bit ISO System-ID for IS-IS and 32-bit Router-ID for OSPFv2 and 786 OSPFv3. In case of additional auxiliary Router-IDs used for TE, 787 these MUST also be included in the link attribute TLV (see 788 Section 9.3.9.2). 790 It is desirable that the Router-ID assignments inside the Node 791 Descriptors TLV are globally unique. Some considerations for 792 globally unique Node/Link/Prefix identifiers are described in 793 [I-D.ietf-idr-rfc7752bis]. 795 The Local Node Descriptors TLV contains Node Descriptors for the node 796 anchoring the local end of the link. This TLV MUST be included in 797 the LS Report when during a given PCEP session a node/link/prefix is 798 first reported to a PCE. A PCC sends to a PCE the first LS Report 799 either during State Synchronization, or when a new node/link/prefix 800 is learned at the PCC. The value contains one or more Node 801 Descriptor Sub-TLVs, which allows the specification of a flexible key 802 for any given node/link/prefix information such that the global 803 uniqueness of the node/link/prefix is ensured. 805 This TLV is applicable for all LS Object-Type. 807 0 1 2 3 808 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 1 809 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 810 | Type=[TBD8] | Length | 811 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 812 | | 813 // Node Descriptor Sub-TLVs (variable) // 814 | | 815 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 817 The value contains one or more Node Descriptor Sub-TLVs defined in 818 Section 9.3.6. 820 9.3.5. Remote Node Descriptors TLV 822 The Remote Node Descriptors contain Node Descriptors for the node 823 anchoring the remote end of the link. This TLV MUST be included in 824 the LS Report when during a given PCEP session a link is first 825 reported to a PCE. A PCC sends to a PCE the first LS Report either 826 during State Synchronization, or when a new link is learned at the 827 PCC. The length of this TLV is variable. The value contains one or 828 more Node Descriptor Sub-TLVs defined in Section 9.3.6. 830 This TLV is applicable for LS Link Object-Type. 832 0 1 2 3 833 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 1 834 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 835 | Type=[TBD9] | Length | 836 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 837 | | 838 // Node Descriptor Sub-TLVs (variable) // 839 | | 840 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 842 9.3.6. Node Descriptors Sub-TLVs 844 The Node Descriptors TLV (Local and Remote) carries one or more Node 845 Descriptor Sub-TLV follows the format of all PCEP TLVs as defined in 846 [RFC5440], however, the Type values are selected from a new PCEP-LS 847 sub-TLV IANA registry (see Section 13.6). 849 Type values are chosen so that there can be commonality with BGP-LS 850 [I-D.ietf-idr-rfc7752bis]. This is possible because the "BGP-LS Node 851 Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs" 852 registry marks 0-255 as reserved. Thus the space of the sub-TLV 853 values for the Type field can be partitioned as shown below - 855 Range | 856 ---------------+--------------------------------------------- 857 0 | Reserved - must not be allocated. 858 | 859 1 .. 255 | New PCEP sub-TLV allocated according to the 860 | registry defined in this document. 861 | 862 256 .. 65535 | Per BGP registry defined by 863 | [I-D.ietf-idr-rfc7752bis]. 864 | Not to be allocated in this registry. 866 All Node Descriptors TLVs defined for BGP-LS can then be used with 867 PCEP-LS as well. One new PCEP sub-TLVs for Node Descriptor are 868 defined in this document. 870 +----------+-------------------+----------+----------------+ 871 | Sub-TLV | Description | Length |Value defined in| 872 +----------+-------------------+----------+----------------+ 873 | 1 | SPEAKER-ENTITY-ID | Variable | [RFC8232] | 874 +----------+-------------------+----------+----------------+ 876 A new sub-TLV type (1) is allocated for SPEAKER-ENTITY-ID sub-TLV. 877 The length and value fields are as per [RFC8232]. 879 9.3.7. Link Descriptors TLV 881 The Link Descriptors TLV contains Link Descriptors for each link. 882 This TLV MUST be included in the LS Report when during a given PCEP 883 session a link is first reported to a PCE. A PCC sends to a PCE the 884 first LS Report either during State Synchronization, or when a new 885 link is learned at the PCC. The length of this TLV is variable. The 886 value contains one or more Link Descriptor Sub-TLVs. 888 The 'Link descriptor' TLVs uniquely identify a link among multiple 889 parallel links between a pair of anchor routers similar to 890 [I-D.ietf-idr-rfc7752bis]. 892 This TLV is applicable for LS Link Object-Type. 894 0 1 2 3 895 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 1 896 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 897 | Type=[TBD10] | Length | 898 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 899 | | 900 // Link Descriptor Sub-TLVs (variable) // 901 | | 902 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 904 All Link Descriptors TLVs defined for BGP-LS can then be used with 905 PCEP-LS as well. No new PCEP sub-TLVs for Link Descriptor are 906 defined in this document. 908 The format and semantics of the 'value' fields in most 'Link 909 Descriptor' sub-TLVs correspond to the format and semantics of value 910 fields in IS-IS Extended IS Reachability sub-TLVs, defined in 911 [RFC5305], [RFC5307] and [RFC6119]. Although the encodings for 'Link 912 Descriptor' TLVs were originally defined for IS-IS, the TLVs can 913 carry data sourced either by IS-IS or OSPF or direct. 915 The information about a link present in the LSA/LSP originated by the 916 local node of the link determines the set of sub-TLVs in the Link 917 Descriptor of the link as described in [I-D.ietf-idr-rfc7752bis]. 919 9.3.8. Prefix Descriptors TLV 921 The Prefix Descriptors TLV contains Prefix Descriptors that uniquely 922 identify an IPv4 or IPv6 Prefix originated by a Node. This TLV MUST 923 be included in the LS Report when during a given PCEP session a 924 prefix is first reported to a PCE. A PCC sends to a PCE the first LS 925 Report either during State Synchronization, or when a new prefix is 926 learned at the PCC. The length of this TLV is variable. 928 This TLV is applicable for LS Prefix Object-Types for both IPv4 and 929 IPv6. 931 0 1 2 3 932 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 1 933 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 934 | Type=[TBD11] | Length | 935 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 936 | | 937 // Prefix Descriptor Sub-TLVs (variable) // 938 | | 939 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 941 All Prefix Descriptors TLVs defined for BGP-LS can then be used with 942 PCEP-LS as well. No new PCEP sub-TLVs for Prefix Descriptor are 943 defined in this document. 945 9.3.9. PCEP-LS Attributes 947 9.3.9.1. Node Attributes TLV 949 This is an optional attribute that is used to carry node attributes. 950 This TLV is applicable for LS Node Object-Type. 952 0 1 2 3 953 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 1 954 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 955 | Type=[TBD12] | Length | 956 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 957 | | 958 // Node Attributes Sub-TLVs (variable) // 959 | | 960 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 962 All Node Attributes TLVs defined for BGP-LS can then be used with 963 PCEP-LS as well. No new PCEP sub-TLVs for Node Attributes are 964 defined in this document. 966 9.3.9.2. Link Attributes TLV 968 This TLV is applicable for LS Link Object-Type. The format and 969 semantics of the 'value' fields in some 'Link Attribute' sub-TLVs 970 correspond to the format and semantics of the 'value' fields in IS-IS 971 Extended IS Reachability sub-TLVs, defined in [RFC5305], [RFC5307] 972 and [I-D.ietf-idr-rfc7752bis]. Although the encodings for 'Link 973 Attribute' TLVs were originally defined for IS-IS, the TLVs can carry 974 data sourced either by IS-IS or OSPF or direct. 976 0 1 2 3 977 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 1 978 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 979 | Type=[TBD13] | Length | 980 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 981 | | 982 // Link Attributes Sub-TLVs (variable) // 983 | | 984 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 986 All Link Attributes TLVs defined for BGP-LS can then be used with 987 PCEP-LS as well. No new PCEP sub-TLVs for Link Attributes are 988 defined in this document. 990 9.3.9.3. Prefix Attributes TLV 992 This TLV is applicable for LS Prefix Object-Types for both IPv4 and 993 IPv6. Prefixes are learned from the IGP (IS-IS or OSPF) or BGP 994 topology with a set of IGP attributes (such as metric, route tags, 995 etc.). This section describes the different attributes related to 996 the IPv4/IPv6 prefixes. Prefix Attributes TLVs SHOULD be encoded in 997 the LS Prefix Object. 999 0 1 2 3 1000 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 1001 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1002 | Type=[TBD14] | Length | 1003 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1004 | | 1005 // Prefix Attributes Sub-TLVs (variable) // 1006 | | 1007 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1009 All Prefix Attributes TLVs defined for BGP-LS can then be used with 1010 PCEP-LS as well. No new PCEP sub-TLVs for Prefix Attributes are 1011 defined in this document. 1013 9.3.10. Removal of an Attribute 1015 One of the key objectives of PCEP-LS is to encode and carry only the 1016 impacted attributes of a Node, a Link, or a Prefix. To accommodate 1017 this requirement, in case of a removal of an attribute, the sub-TLV 1018 MUST be included with no 'value' field and length=0 to indicate that 1019 the attribute is removed. On receiving a sub-TLV with zero length, 1020 the receiver removes the attribute from the database. An absence of 1021 a sub-TLV that was included earlier MUST be interpreted as no change. 1023 10. Other Considerations 1025 10.1. Inter-AS Links 1027 The main source of LS (and TE) information is the IGP, which is not 1028 active on inter-AS links. In some cases, the IGP may have 1029 information of inter-AS links ([RFC5392], [RFC5316]). In other 1030 cases, an implementation SHOULD provide a means to inject inter-AS 1031 links into PCEP. The exact mechanism used to provision the inter-AS 1032 links is outside the scope of this document. 1034 11. Security Considerations 1036 This document extends PCEP for LS (and TE) distribution including a 1037 new LSRpt message with a new object and TLVs. Procedures and 1038 protocol extensions defined in this document do not effect the 1039 overall PCEP security model. See [RFC5440], [RFC8253]. Tampering 1040 with the LSRpt message may have an effect on path computations at 1041 PCE. It also provides adversaries an opportunity to eavesdrop and 1042 learn sensitive information and plan sophisticated attacks on the 1043 network infrastructure. The PCE implementation SHOULD provide 1044 mechanisms to prevent strains created by network flaps and amount of 1045 LS (and TE) information. Thus it is suggested that any mechanism 1046 used for securing the transmission of other PCEP message be applied 1047 here as well. As a general precaution, it is RECOMMENDED that these 1048 PCEP extensions only are activated on authenticated and encrypted 1049 sessions belonging to the same administrative authority. 1051 Further, as stated in [RFC6952], PCEP implementations SHOULD support 1052 the TCP-AO [RFC5925] and not use TCP MD5 because of TCP MD5's known 1053 vulnerabilities and weaknesses. PCEP also support Transport Layer 1054 Security (TLS) [RFC8253] as per the recommendations and best current 1055 practices in [RFC7525]. 1057 12. Manageability Considerations 1059 All manageability requirements and considerations listed in [RFC5440] 1060 apply to PCEP protocol extensions defined in this document. In 1061 addition, requirements, and considerations listed in this section 1062 apply. 1064 12.1. Control of Function and Policy 1066 A PCE or PCC implementation MUST allow configuring the PCEP-LS 1067 capabilities as described in this document. 1069 A PCC implementation SHOULD allow configuration to suggest if remote 1070 information learned via routing protocols should be reported or not. 1072 An implementation SHOULD allow the operator to specify the maximum 1073 number of LS data to be reported. 1075 An implementation SHOULD also allow the operator to create abstracted 1076 topologies that are reported to the peers and create different 1077 abstractions for different peers. 1079 An implementation SHOULD allow the operator to configure a 64-bit 1080 identifier for Routing Universe TLV. 1082 12.2. Information and Data Models 1084 An implementation SHOULD allow the operator to view the LS 1085 capabilities advertised by each peer. To serve this purpose, the 1086 PCEP YANG module [I-D.ietf-pce-pcep-yang] can be extended to include 1087 advertised capabilities. 1089 An implementation SHOULD also provide the statistics: 1091 o Total number of LSRpt sent/received, as well as per neighbour 1093 o Number of errors received for LSRpt, per neighbour 1095 o Total number of locally originated Link-State Information 1097 These statistics should be recorded as absolute counts since system 1098 or session start time. An implementation MAY also enhance this 1099 information by recording peak per-second counts in each case. 1101 An operator SHOULD define an import policy to limit inbound LSRpt to 1102 "drop all LSRpt from a particular peer" as well provide means to 1103 limit inbound LSRpts. 1105 12.3. Liveness Detection and Monitoring 1107 Mechanisms defined in this document do not imply any new liveness 1108 detection and monitoring requirements in addition to those already 1109 listed in [RFC5440]". 1111 12.4. Verify Correct Operations 1113 Mechanisms defined in this document do not imply any new operation 1114 verification requirements in addition to those already listed in 1115 [RFC5440] . 1117 12.5. Requirements On Other Protocols 1119 Mechanisms defined in this document do not imply any new requirements 1120 on other protocols. 1122 12.6. Impact On Network Operations 1124 Mechanisms defined in this document do not have any impact on network 1125 operations in addition to those already listed in [RFC5440]. 1127 13. IANA Considerations 1129 This document requests IANA actions to allocate code points for the 1130 protocol elements defined in this document. 1132 13.1. PCEP Messages 1134 IANA created a registry for "PCEP Messages". Each PCEP message has a 1135 message type value. This document defines a new PCEP message value. 1137 Value Meaning Reference 1138 TBD3 LSRpt [This I-D] 1140 13.2. PCEP Objects 1142 This document defines the following new PCEP Object-classes and 1143 Object-values: 1145 Object-Class Value Name Reference 1146 TBD6 LS Object [This I-D] 1147 Object-Type=1 1148 (LS Node) 1149 Object-Type=2 1150 (LS Link) 1151 Object-Type=3 1152 (LS IPv4 Prefix) 1153 Object-Type=4 1154 (LS IPv6 Prefix) 1156 13.3. LS Object 1158 This document requests that a new sub-registry, named "LS Object 1159 Protocol-ID Field", is created within the "Path Computation Element 1160 Protocol (PCEP) Numbers" registry to manage the Flag field of the LSP 1161 object. New values are to be assigned by Standards Action [RFC8126]. 1163 Value Meaning Reference 1164 0 Reserved [This I-D] 1165 1 IS-IS Level 1 [This I-D] 1166 2 IS-IS Level 2 [This I-D] 1167 3 OSPFv2 [This I-D] 1168 4 Direct [This I-D] 1169 5 Static configuration [This I-D] 1170 6 OSPFv3 [This I-D] 1171 7 BGP [This I-D] 1172 8 RSVP-TE [This I-D] 1173 9 Segment Routing [This I-D] 1174 10 PCEP [This I-D] 1175 11 Abstraction [This I-D] 1176 12-255 Unassigned 1178 Further, this document also requests that a new sub-registry, named 1179 "LS Object Flag Field", is created within the "Path Computation 1180 Element Protocol (PCEP) Numbers" registry to manage the Flag field of 1181 the LSP object.New values are to be assigned by Standards Action 1182 [RFC8126]. Each bit should be tracked with the following qualities: 1184 o Bit number (counting from bit 0 as the most significant bit) 1186 o Capability description 1188 o Defining RFC 1190 The following values are defined in this document: 1192 Bit Description Reference 1193 0-21 Unassigned 1194 22 R (Remove bit) [This I-D] 1195 23 S (Sync bit) [This I-D] 1197 13.4. PCEP-Error Object 1199 IANA is requested to make the following allocation in the "PCEP-ERROR 1200 Object Error Types and Values" registry. 1202 Error-Type Meaning Reference 1203 6 Mandatory Object missing [RFC5440] 1204 Error-Value=TBD4 [This I-D] 1205 (LS object missing) 1207 19 Invalid Operation [RFC8231] 1208 Error-Value=TBD1 [This I-D] 1209 (Attempted LS Report if LS 1210 remote capability was not 1211 advertised) 1213 TBD2 LS Synchronization Error [This I-D] 1214 Error-Value=1 1215 (An error in processing the 1216 LSRpt) 1217 Error-Value=2 1218 (An internal PCC error) 1220 13.5. PCEP TLV Type Indicators 1222 This document defines the following new PCEP TLVs. 1224 Value Meaning Reference 1225 TBD5 LS-CAPABILITY TLV [This I-D] 1226 TBD7 ROUTING-UNIVERSE TLV [This I-D] 1227 TBD15 ROUTE-DISTINGUISHER TLV [This I-D] 1228 TBD8 Local Node Descriptors TLV [This I-D] 1229 TBD9 Remote Node Descriptors TLV [This I-D] 1230 TBD10 Link Descriptors TLV [This I-D] 1231 TBD11 Prefix Descriptors TLV [This I-D] 1232 TBD12 Node Attributes TLV [This I-D] 1233 TBD13 Link Attributes TLV [This I-D] 1234 TBD14 Prefix Attributes TLV [This I-D] 1236 13.6. PCEP-LS Sub-TLV Type Indicators 1238 This document specifies the PCEP-LS Sub-TLVs. IANA is requested to 1239 create an "PCEP-LS Sub-TLV Types" sub-registry for the sub-TLVs 1240 carried in the PCEP-LS TLV (Local and Remote Node Descriptors TLV, 1241 Link Descriptors TLV, Prefix Descriptors TLV, Node Attributes TLV, 1242 Link Attributes TLV and Prefix Attributes TLV. 1244 Allocations from this registry are to be made according to the 1245 following assignment policies [RFC8126]: 1247 Range | Assignment policy 1248 ---------------+--------------------------------------------------- 1249 0 | Reserved - must not be allocated. 1250 | 1251 1 .. 251 | Specification Required 1252 | 1253 252 .. 255 | Experimental Use 1254 | 1255 256 .. 65535 | Reserved - must not be allocated. 1256 | Usage mirrors the BGP-LS TLV registry 1257 | [I-D.ietf-idr-rfc7752bis] 1258 | 1260 IANA is requested to pre-populate this registry with values defined 1261 in this document as follows, taking the new values from the range 1 1262 to 251: 1264 Value | Meaning 1265 -------+------------------------ 1266 1 | SPEAKER-ENTITY-ID 1268 14. TLV Code Points Summary 1270 This section contains the global table of all TLVs in LS object 1271 defined in this document. 1273 +-----------+---------------------+---------------+-----------------+ 1274 | TLV | Description | Ref TLV | Value defined | 1275 | | | | in: | 1276 +-----------+---------------------+---------------+-----------------+ 1277 | TBD7 | Routing Universe | -- | Sec 9.2.1 | 1278 | TBD15 | Route | -- | Sec 9.2.2 | 1279 | | Distinguisher | | | 1280 | * | Virtual Network | -- | [ietf-pce- | 1281 | | | | vn-association] | 1282 | TBD8 | Local Node | 256 | [I-D.ietf-idr- | 1283 | | | | rfc7752bis] | 1284 | | Descriptors | | /3.2.1.2 | 1285 | TBD9 | Remote Node | 257 | [I-D.ietf-idr- | 1286 | | | | rfc7752bis] | 1287 | | Descriptors | | /3.2.1.3 | 1288 | TBD10 | Link Descriptors | -- | Sec 9.2.8 | 1289 | TBD11 | Prefix Descriptors | -- | Sec 9.2.9 | 1290 | TBD12 | Node Attributes | -- | Sec 9.2.10.1 | 1291 | TBD13 | Link Attributes | -- | Sec 9.2.10.2 | 1292 | TBD14 | Prefix Attributes | -- | Sec 9.2.10.3 | 1293 +-----------+---------------------+---------------+-----------------+ 1295 * this TLV is defined in a different PCEP document 1297 TLV Table 1299 15. Implementation Status 1301 The PCEP-LS protocol extensions as described in this I-D were 1302 implemented and tested for a variety of applications. Apart from the 1303 below implementation, there exist other experimental implementations 1304 done for optical networks. 1306 15.1. Hierarchical Transport PCE controllers 1308 The PCEP-LS has been implemented as part of IETF97 Hackathon and 1309 Bits-N-Bites demonstration. The use-case demonstrated was DCI use- 1310 case of ACTN architecture in which to show the following scenarios: 1312 - connectivity services on the ACTN based recursive hierarchical 1313 SDN/PCE platform that has the three-tier level SDN controllers 1314 (two-tier level MDSC and PNC) on the top of the PTN systems 1315 managed by EMS. 1317 - Integration test of two tier-level MDSC: The SBI of the low 1318 level MDSC is the YANG based Korean national standards and the one 1319 of the high-level MDSC the PCEP-LS based ACTN protocols. 1321 - Performance test of three types of SDN controller based recovery 1322 schemes including protection, reactive, and proactive restoration. 1323 PCEP-LS protocol was used to demonstrate a quick report of failed 1324 network components. 1326 15.2. ONOS-based Controller (MDSC and PNC) 1328 Huawei (PNC, MDSC) and SKT (MDSC) implemented PCEP-LS during 1329 Hackathon and IETF97 Bits-N-Bites demonstration. The demonstration 1330 was ONOS-based ACTN architecture in which to show the following 1331 capabilities: 1333 Both packet PNC and optical PNC (with optical PCEP-LS extensions) 1334 implemented PCEP-LS on its SBI as well as its NBI (towards MDSC). 1336 SKT orchestrator (acting as MDSC) also supported PCEP-LS (as well 1337 as RestConf) towards packet and optical PNCs on its SBI. 1339 Further description can be found at and the code at 1340 . 1342 16. Acknowledgments 1344 This document borrows some of the structure and text from the 1345 [I-D.ietf-idr-rfc7752bis]. 1347 Thanks to Eric Wu, Venugopal Kondreddy, Mahendra Singh Negi, 1348 Avantika, and Zhengbin Li for the reviews. 1350 Thanks to Ramon Casellas for his comments and suggestions based on 1351 his implementation experience. 1353 17. References 1355 17.1. Normative References 1357 [I-D.ietf-idr-rfc7752bis] 1358 Talaulikar, K., "Distribution of Link-State and Traffic 1359 Engineering Information Using BGP", draft-ietf-idr- 1360 rfc7752bis-04 (work in progress), September 2020. 1362 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1363 Requirement Levels", BCP 14, RFC 2119, 1364 DOI 10.17487/RFC2119, March 1997, 1365 . 1367 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 1368 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 1369 2008, . 1371 [RFC5307] Kompella, K., Ed. and Y. Rekhter, Ed., "IS-IS Extensions 1372 in Support of Generalized Multi-Protocol Label Switching 1373 (GMPLS)", RFC 5307, DOI 10.17487/RFC5307, October 2008, 1374 . 1376 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 1377 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 1378 DOI 10.17487/RFC5440, March 2009, 1379 . 1381 [RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic 1382 Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119, 1383 February 2011, . 1385 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1386 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1387 May 2017, . 1389 [RFC8232] Crabbe, E., Minei, I., Medved, J., Varga, R., Zhang, X., 1390 and D. Dhody, "Optimizations of Label Switched Path State 1391 Synchronization Procedures for a Stateful PCE", RFC 8232, 1392 DOI 10.17487/RFC8232, September 2017, 1393 . 1395 17.2. Informative References 1397 [I-D.ietf-pce-pcep-flowspec] 1398 Dhody, D., Farrel, A., and Z. Li, "PCEP Extension for Flow 1399 Specification", draft-ietf-pce-pcep-flowspec-12 (work in 1400 progress), October 2020. 1402 [I-D.ietf-pce-pcep-yang] 1403 Dhody, D., Hardwick, J., Beeram, V., and J. Tantsura, "A 1404 YANG Data Model for Path Computation Element 1405 Communications Protocol (PCEP)", draft-ietf-pce-pcep- 1406 yang-15 (work in progress), October 2020. 1408 [I-D.ietf-pce-vn-association] 1409 Lee, Y., Zheng, H., and D. Ceccarelli, "Path Computation 1410 Element communication Protocol (PCEP) extensions for 1411 Establishing Relationships between sets of LSPs and 1412 Virtual Networks", draft-ietf-pce-vn-association-03 (work 1413 in progress), October 2020. 1415 [I-D.ietf-teas-actn-requirements] 1416 Lee, Y., Ceccarelli, D., Miyasaka, T., Shin, J., and K. 1417 Lee, "Requirements for Abstraction and Control of TE 1418 Networks", draft-ietf-teas-actn-requirements-09 (work in 1419 progress), March 2018. 1421 [I-D.kondreddy-pce-pcep-ls-sync-optimizations] 1422 Kondreddy, V. and M. Negi, "Optimizations of PCEP Link- 1423 State(LS) Synchronization Procedures", draft-kondreddy- 1424 pce-pcep-ls-sync-optimizations-00 (work in progress), 1425 October 2015. 1427 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 1428 (TE) Extensions to OSPF Version 2", RFC 3630, 1429 DOI 10.17487/RFC3630, September 2003, 1430 . 1432 [RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in 1433 Support of Generalized Multi-Protocol Label Switching 1434 (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, 1435 . 1437 [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private 1438 Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February 1439 2006, . 1441 [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation 1442 Element (PCE)-Based Architecture", RFC 4655, 1443 DOI 10.17487/RFC4655, August 2006, 1444 . 1446 [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in 1447 Support of Inter-Autonomous System (AS) MPLS and GMPLS 1448 Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316, 1449 December 2008, . 1451 [RFC5392] Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in 1452 Support of Inter-Autonomous System (AS) MPLS and GMPLS 1453 Traffic Engineering", RFC 5392, DOI 10.17487/RFC5392, 1454 January 2009, . 1456 [RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP 1457 Authentication Option", RFC 5925, DOI 10.17487/RFC5925, 1458 June 2010, . 1460 [RFC6549] Lindem, A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi- 1461 Instance Extensions", RFC 6549, DOI 10.17487/RFC6549, 1462 March 2012, . 1464 [RFC6805] King, D., Ed. and A. Farrel, Ed., "The Application of the 1465 Path Computation Element Architecture to the Determination 1466 of a Sequence of Domains in MPLS and GMPLS", RFC 6805, 1467 DOI 10.17487/RFC6805, November 2012, 1468 . 1470 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 1471 BGP, LDP, PCEP, and MSDP Issues According to the Keying 1472 and Authentication for Routing Protocols (KARP) Design 1473 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 1474 . 1476 [RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, 1477 "Recommendations for Secure Use of Transport Layer 1478 Security (TLS) and Datagram Transport Layer Security 1479 (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May 1480 2015, . 1482 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1483 Writing an IANA Considerations Section in RFCs", BCP 26, 1484 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1485 . 1487 [RFC8202] Ginsberg, L., Previdi, S., and W. Henderickx, "IS-IS 1488 Multi-Instance", RFC 8202, DOI 10.17487/RFC8202, June 1489 2017, . 1491 [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path 1492 Computation Element Communication Protocol (PCEP) 1493 Extensions for Stateful PCE", RFC 8231, 1494 DOI 10.17487/RFC8231, September 2017, 1495 . 1497 [RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody, 1498 "PCEPS: Usage of TLS to Provide a Secure Transport for the 1499 Path Computation Element Communication Protocol (PCEP)", 1500 RFC 8253, DOI 10.17487/RFC8253, October 2017, 1501 . 1503 [RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path 1504 Computation Element Communication Protocol (PCEP) 1505 Extensions for PCE-Initiated LSP Setup in a Stateful PCE 1506 Model", RFC 8281, DOI 10.17487/RFC8281, December 2017, 1507 . 1509 [RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An 1510 Architecture for Use of PCE and the PCE Communication 1511 Protocol (PCEP) in a Network with Central Control", 1512 RFC 8283, DOI 10.17487/RFC8283, December 2017, 1513 . 1515 [RFC8453] Ceccarelli, D., Ed. and Y. Lee, Ed., "Framework for 1516 Abstraction and Control of TE Networks (ACTN)", RFC 8453, 1517 DOI 10.17487/RFC8453, August 2018, 1518 . 1520 [RFC8637] Dhody, D., Lee, Y., and D. Ceccarelli, "Applicability of 1521 the Path Computation Element (PCE) to the Abstraction and 1522 Control of TE Networks (ACTN)", RFC 8637, 1523 DOI 10.17487/RFC8637, July 2019, 1524 . 1526 Appendix A. Examples 1528 These examples are for illustration purposes only to show how the new 1529 PCEP-LS message could be encoded. They are not meant to be an 1530 exhaustive list of all possible use cases and combinations. 1532 A.1. All Nodes 1534 Each node (PCC) in the network chooses to provide its own local node 1535 and link information, and in this way PCE can build the full link- 1536 state and TE information. 1538 +--------------------+ +--------------------+ 1539 | | | | 1540 | RTA |10.1.1.1 | RTB | 1541 | 1.1.1.1 |--------------------| 2.2.2.2 | 1542 | Area 0 | 10.1.1.2| Area 0 | 1543 | | | | 1544 +--------------------+ +--------------------+ 1545 RTA 1546 --- 1547 LS Node 1548 TLV - Local Node Descriptors 1549 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1550 Sub-TLV - 515: Router-ID: 1.1.1.1 1551 TLV - Node Attributes TLV 1552 Sub-TLV(s) 1554 LS Link 1555 TLV - Local Node Descriptors 1556 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1557 Sub-TLV - 515: Router-ID: 1.1.1.1 1558 TLV - Remote Node Descriptors 1559 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1560 Sub-TLV - 515: Router-ID: 2.2.2.2 1561 TLV - Link Descriptors 1562 Sub-TLV - 259: IPv4 interface: 10.1.1.1 1563 Sub-TLV - 260: IPv4 neighbor: 10.1.1.2 1564 TLV - Link Attributes TLV 1565 Sub-TLV(s) 1567 RTB 1568 --- 1569 LS Node 1570 TLV - Local Node Descriptors 1571 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1572 Sub-TLV - 515: Router-ID: 2.2.2.2 1574 TLV - Node Attributes TLV 1575 Sub-TLV(s) 1577 LS Link 1578 TLV - Local Node Descriptors 1579 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1580 Sub-TLV - 515: Router-ID: 2.2.2.2 1581 TLV - Remote Node Descriptors 1582 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1583 Sub-TLV - 515: Router-ID: 1.1.1.1 1584 TLV - Link Descriptors 1585 Sub-TLV - 259: IPv4 interface: 10.1.1.2 1586 Sub-TLV - 260: IPv4 neighbor: 10.1.1.1 1587 TLV - Link Attributes TLV 1588 Sub-TLV(s) 1590 A.2. Designated Node 1592 A designated node(s) in the network will provide its own local node 1593 as well as all learned remote information, and in this way PCE can 1594 build the full link-state and TE information. 1596 As described in Appendix A.1, the same LS Node and Link objects will 1597 be generated with a difference that it would be a designated router 1598 say RTA that generate all this information. 1600 A.3. Between PCEs 1602 As per Hierarchical-PCE [RFC6805], Parent PCE builds an abstract 1603 domain topology map with each domain as an abstract node and inter- 1604 domain links as an abstract link. Each child PCE may provide this 1605 information to the parent PCE. Considering the example in figure 1 1606 of [RFC6805], following LS object will be generated: 1608 PCE1 1609 ---- 1610 LS Node 1611 TLV - Local Node Descriptors 1612 Sub-TLV - 512: Autonomous System: 100 (Domain 1) 1613 Sub-TLV - 515: Router-ID: 11.11.11.11 (abstract) 1615 LS Link 1616 TLV - Local Node Descriptors 1617 Sub-TLV - 512: Autonomous System: 100 1618 Sub-TLV - 515: Router-ID: 11.11.11.11 (abstract) 1619 TLV - Remote Node Descriptors 1620 Sub-TLV - 512: Autonomous System: 200 (Domain 2) 1621 Sub-TLV - 515: Router-ID: 22.22.22.22 (abstract) 1622 TLV - Link Descriptors 1623 Sub-TLV - 259: IPv4 interface: 11.1.1.1 1624 Sub-TLV - 260: IPv4 neighbor: 11.1.1.2 1625 TLV - Link Attributes TLV 1626 Sub-TLV(s) 1628 LS Link 1629 TLV - Local Node Descriptors 1630 Sub-TLV - 512: Autonomous System: 100 1631 Sub-TLV - 515: Router-ID: 11.11.11.11 (abstract) 1632 TLV - Remote Node Descriptors 1633 Sub-TLV - 512: Autonomous System: 200 1634 Sub-TLV - 515: Router-ID: 22.22.22.22 (abstract) 1635 TLV - Link Descriptors 1636 Sub-TLV - 259: IPv4 interface: 12.1.1.1 1637 Sub-TLV - 260: IPv4 neighbor: 12.1.1.2 1638 TLV - Link Attributes TLV 1639 Sub-TLV(s) 1641 LS Link 1642 TLV - Local Node Descriptors 1643 Sub-TLV - 512: Autonomous System: 100 1644 Sub-TLV - 515: Router-ID: 11.11.11.11 (abstract) 1645 TLV - Remote Node Descriptors 1646 Sub-TLV - 512: Autonomous System: 400 (Domain 4) 1647 Sub-TLV - 515: Router-ID: 44.44.44.44 (abstract) 1648 TLV - Link Descriptors 1649 Sub-TLV - 259: IPv4 interface: 13.1.1.1 1650 Sub-TLV - 260: IPv4 neighbor: 13.1.1.2 1651 TLV - Link Attributes TLV 1652 Sub-TLV(s) 1654 * similar information will be generated by other PCE 1655 to help form the abstract domain topology. 1657 Further the exact border nodes and abstract internal path between the 1658 border nodes may also be transported to the Parent PCE to enable ACTN 1659 as described in [RFC8637] using the similar LS node and link objects 1660 encodings. 1662 Appendix B. Contributor Addresses 1664 Udayasree Palle 1666 EMail: udayasreereddy@gmail.com 1668 Sergio Belotti 1669 Nokia 1671 EMail: sergio.belotti@nokia.com 1673 Satish Karunanithi 1674 Huawei Technologies 1675 Divyashree Techno Park, Whitefield 1676 Bangalore, Karnataka 560066 1677 India 1679 Email: satishk@huawei.com 1681 Cheng Li 1682 Huawei Technologies 1683 Huawei Campus, No. 156 Beiqing Rd. 1684 Beijing 100095 1685 China 1687 Email: c.l@huawei.com 1689 Authors' Addresses 1691 Dhruv Dhody 1692 Huawei Technologies 1693 Divyashree Techno Park, Whitefield 1694 Bangalore, Karnataka 560066 1695 India 1697 EMail: dhruv.ietf@gmail.com 1698 Shuping Peng 1699 Huawei Technologies 1700 Huawei Bld., No.156 Beiqing Rd. 1701 Beijing 100095 1702 China 1704 EMail: pengshuping@huawei.com 1706 Young Lee 1707 Samsung Electronics 1708 Seoul 1709 South Korea 1711 EMail: younglee.tx@gmail.com 1713 Daniele Ceccarelli 1714 Ericsson 1715 Torshamnsgatan,48 1716 Stockholm 1717 Sweden 1719 EMail: daniele.ceccarelli@ericsson.com 1721 Aijun Wang 1722 China Telecom 1723 Beiqijia Town, Changping District 1724 Beijing, Beijing 102209 1725 China 1727 EMail: wangaj3@chinatelecom.cn