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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: September 10, 2020 Y. Lee 6 Samsung Electronics 7 D. Ceccarelli 8 Ericsson 9 March 9, 2020 11 PCEP extensions for Distribution of Link-State and TE Information 12 draft-dhodylee-pce-pcep-ls-15 14 Abstract 16 In order to compute and provide optimal paths, Path Computation 17 Elements (PCEs) require an accurate and timely Traffic Engineering 18 Database (TED). Traditionally this TED has been obtained from a link 19 state (LS) routing protocol supporting traffic engineering 20 extensions. 22 This document extends the Path Computation Element Communication 23 Protocol (PCEP) with Link-State and TE Information. 25 Requirements Language 27 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 28 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 29 "OPTIONAL" in this document are to be interpreted as described in BCP 30 14 [RFC2119] [RFC8174] when, and only when, they appear in all 31 capitals, as shown here. 33 Status of This Memo 35 This Internet-Draft is submitted in full conformance with the 36 provisions of BCP 78 and BCP 79. 38 Internet-Drafts are working documents of the Internet Engineering 39 Task Force (IETF). Note that other groups may also distribute 40 working documents as Internet-Drafts. The list of current Internet- 41 Drafts is at https://datatracker.ietf.org/drafts/current/. 43 Internet-Drafts are draft documents valid for a maximum of six months 44 and may be updated, replaced, or obsoleted by other documents at any 45 time. It is inappropriate to use Internet-Drafts as reference 46 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on September 10, 2020. 50 Copyright Notice 52 Copyright (c) 2020 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents 57 (https://trustee.ietf.org/license-info) in effect on the date of 58 publication of this document. Please review these documents 59 carefully, as they describe your rights and restrictions with respect 60 to this document. Code Components extracted from this document must 61 include Simplified BSD License text as described in Section 4.e of 62 the Trust Legal Provisions and are provided without warranty as 63 described in the Simplified BSD License. 65 Table of Contents 67 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 68 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 69 3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 5 70 4. Requirements for PCEP extensions . . . . . . . . . . . . . . 6 71 5. New Functions to distribute link-state (and TE) via PCEP . . 7 72 6. Overview of Extensions to PCEP . . . . . . . . . . . . . . . 7 73 6.1. New Messages . . . . . . . . . . . . . . . . . . . . . . 7 74 6.2. Capability Advertisement . . . . . . . . . . . . . . . . 8 75 6.3. Initial Link-State (and TE) Synchronization . . . . . . . 8 76 6.3.1. Optimizations for LS Synchronization . . . . . . . . 11 77 6.4. LS Report . . . . . . . . . . . . . . . . . . . . . . . . 11 78 7. Transport . . . . . . . . . . . . . . . . . . . . . . . . . . 11 79 8. PCEP Messages . . . . . . . . . . . . . . . . . . . . . . . . 12 80 8.1. LS Report Message . . . . . . . . . . . . . . . . . . . . 12 81 8.2. The PCErr Message . . . . . . . . . . . . . . . . . . . . 12 82 9. Objects and TLV . . . . . . . . . . . . . . . . . . . . . . . 13 83 9.1. TLV Format . . . . . . . . . . . . . . . . . . . . . . . 13 84 9.2. Open Object . . . . . . . . . . . . . . . . . . . . . . . 13 85 9.2.1. LS Capability TLV . . . . . . . . . . . . . . . . . . 13 86 9.3. LS Object . . . . . . . . . . . . . . . . . . . . . . . . 14 87 9.3.1. Routing Universe TLV . . . . . . . . . . . . . . . . 16 88 9.3.2. Route Distinguisher TLV . . . . . . . . . . . . . . . 17 89 9.3.3. Virtual Network TLV . . . . . . . . . . . . . . . . . 17 90 9.3.4. Local Node Descriptors TLV . . . . . . . . . . . . . 17 91 9.3.5. Remote Node Descriptors TLV . . . . . . . . . . . . . 18 92 9.3.6. Node Descriptors Sub-TLVs . . . . . . . . . . . . . . 19 93 9.3.7. Link Descriptors TLV . . . . . . . . . . . . . . . . 19 94 9.3.8. Prefix Descriptors TLV . . . . . . . . . . . . . . . 20 95 9.3.9. PCEP-LS Attributes . . . . . . . . . . . . . . . . . 21 96 9.3.9.1. Node Attributes TLV . . . . . . . . . . . . . . . 21 97 9.3.9.2. Link Attributes TLV . . . . . . . . . . . . . . . 21 98 9.3.9.3. Prefix Attributes TLV . . . . . . . . . . . . . . 22 99 9.3.10. Removal of an Attribute . . . . . . . . . . . . . . . 22 100 10. Other Considerations . . . . . . . . . . . . . . . . . . . . 22 101 10.1. Inter-AS Links . . . . . . . . . . . . . . . . . . . . . 22 102 11. Security Considerations . . . . . . . . . . . . . . . . . . . 23 103 12. Manageability Considerations . . . . . . . . . . . . . . . . 23 104 12.1. Control of Function and Policy . . . . . . . . . . . . . 23 105 12.2. Information and Data Models . . . . . . . . . . . . . . 24 106 12.3. Liveness Detection and Monitoring . . . . . . . . . . . 24 107 12.4. Verify Correct Operations . . . . . . . . . . . . . . . 24 108 12.5. Requirements On Other Protocols . . . . . . . . . . . . 24 109 12.6. Impact On Network Operations . . . . . . . . . . . . . . 24 110 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 111 13.1. PCEP Messages . . . . . . . . . . . . . . . . . . . . . 25 112 13.2. PCEP Objects . . . . . . . . . . . . . . . . . . . . . . 25 113 13.3. LS Object . . . . . . . . . . . . . . . . . . . . . . . 25 114 13.4. PCEP-Error Object . . . . . . . . . . . . . . . . . . . 26 115 13.5. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 27 116 13.6. PCEP-LS Sub-TLV Type Indicators . . . . . . . . . . . . 27 117 14. TLV Code Points Summary . . . . . . . . . . . . . . . . . . . 28 118 15. Implementation Status . . . . . . . . . . . . . . . . . . . . 29 119 15.1. Hierarchical Transport PCE controllers . . . . . . . . . 29 120 15.2. ONOS-based Controller (MDSC and PNC) . . . . . . . . . . 30 121 16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 30 122 17. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 123 17.1. Normative References . . . . . . . . . . . . . . . . . . 30 124 17.2. Informative References . . . . . . . . . . . . . . . . . 31 125 Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 35 126 A.1. All Nodes . . . . . . . . . . . . . . . . . . . . . . . . 35 127 A.2. Designated Node . . . . . . . . . . . . . . . . . . . . . 36 128 A.3. Between PCEs . . . . . . . . . . . . . . . . . . . . . . 36 129 Appendix B. Contributor Addresses . . . . . . . . . . . . . . . 38 130 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38 132 1. Introduction 134 In Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS), 135 a Traffic Engineering Database (TED) is used in computing paths for 136 connection oriented packet services and for circuits. The TED 137 contains all relevant information that a Path Computation Element 138 (PCE) needs to perform its computations. It is important that the 139 TED be 'complete and accurate' each time the PCE performs a path 140 computation. 142 In MPLS and GMPLS, interior gateway routing protocols (Interior 143 Gateway Protocol (IGPs)) have been used to create and maintain a copy 144 of the TED at each node running the IGP. One of the benefits of the 145 PCE architecture [RFC4655] is the use of computationally more 146 sophisticated path computation algorithms and the realization that 147 these may need enhanced processing power (not necessarily available 148 at each node). 150 Section 4.3 of [RFC4655] describes the potential load of the TED on a 151 network node and proposes an architecture where the TED is maintained 152 by the PCE rather than the network nodes. However, it does not 153 describe how a PCE would obtain the information needed to populate 154 its TED. PCE may construct its TED by participating in the IGP 155 ([RFC3630] and [RFC5305] for MPLS-TE; [RFC4203] and [RFC5307] for 156 GMPLS). An alternative mechanism is offered by BGP-LS [RFC7752] . 158 [RFC8231] describes a set of extensions to PCEP to provide stateful 159 control. A stateful PCE has access to not only the information 160 carried by the network's IGP, but also the set of active paths and 161 their reserved resources for its computations. Path Computation 162 Client (PCC) can delegate the rights to modify the LSP parameters to 163 an Active Stateful PCE. This requires PCE to quickly be updated on 164 any changes in the topology/TED, so that PCE can meet the need for 165 updating LSPs effectively and in a timely manner. The fastest way 166 for a PCE to be updated on TED changes is via a direct session with 167 each network node and with incremental update from each network node 168 with only the attributes that gets modified. 170 [RFC8281] describes the setup, maintenance and teardown of PCE- 171 initiated LSPs under the stateful PCE model, without the need for 172 local configuration on the PCC, thus allowing for a dynamic network 173 that is centrally controlled and deployed. This model requires 174 timely topology and TED update at the PCE. 176 [RFC5440] describes the specifications for the Path Computation 177 Element Communication Protocol (PCEP). PCEP specifies the 178 communication between a PCC and a PCE, or between two PCEs based on 179 the PCE architecture [RFC4655]. 181 This document describes a mechanism by which link-state and TE 182 information can be collected from networks and shared with PCE using 183 the PCEP itself. This is achieved using a new PCEP message format. 184 The mechanism is applicable to physical and virtual links as well as 185 further subjected to various policies. 187 A network node maintains one or more databases for storing link-state 188 and TE information about nodes and links in any given area. Link 189 attributes stored in these databases include: local/remote IP 190 addresses, local/remote interface identifiers, link metric and TE 191 metric, link bandwidth, reservable bandwidth, per CoS class 192 reservation state, preemption and Shared Risk Link Groups (SRLG). 193 The node's PCEP process can retrieve topology from these databases 194 and distribute it to a PCE, either directly or via another PCEP 195 Speaker, using the encoding specified in this document. 197 Further [RFC6805] describes Hierarchical-PCE architecture, where a 198 parent PCE maintains a domain topology map. To build this domain 199 topology map, the child PCE can carry the border nodes and inter- 200 domain link information to the parent PCE using the mechanism 201 described in this document. Further as described in [RFC8637], the 202 child PCE can also transport abstract Link-State and TE information 203 from child PCE to a Parent PCE using the mechanism described in this 204 document to build an abstract topology at the parent PCE. 206 [RFC8231] describe LSP state synchronization between PCCs and PCEs in 207 case of stateful PCE. This document does not make any change to the 208 LSP state synchronization process. The mechanism described in this 209 document are on top of the existing LSP state synchronization. 211 2. Terminology 213 The terminology is as per [RFC4655] and [RFC5440]. 215 3. Applicability 217 The mechanism specified in this draft is applicable to deployments: 219 o Where there is no IGP or BGP-LS running in the network. 221 o Where there is no IGP or BGP-LS running at the PCE to learn link- 222 state and TE information. 224 o Where there is IGP or BGP-LS running but with a need for a faster 225 and direct TE and link-state population and convergence at the 226 PCE. 228 * A PCE may receive partial information (say basic TE, link- 229 state) from IGP and other information (optical and impairment) 230 from PCEP. 232 * A PCE may receive an incremental update (as opposed to the full 233 (entire) information of the node/link). 235 * A PCE may receive full information from both existing mechanism 236 (IGP or BGP-LS) and PCEP. 238 o Where there is a need for transporting (abstract) Link-State and 239 TE information from child PCE to a Parent PCE in H-PCE [RFC6805]; 240 as well as for Provisioning Network Controller (PNC) to Multi- 241 Domain Service Coordinator (MDSC) in Abstraction and Control of TE 242 Networks (ACTN) [RFC8453]. 244 o Where there is an existing PCEP session between all the nodes and 245 the PCE-based central controller (PCECC) [RFC8283], and the 246 operator would like to use PCEP as a direct south bound interface 247 to all the nodes in the network. This enables operator to use 248 PCEP as single direct protocol between the controller and all the 249 nodes in the network. In this mode all nodes send only the local 250 information. 252 Based on the local policy and deployment scenario, a PCC chooses to 253 send only local information or both local and remote learned 254 information. How a PCE manages the link-state (and TE) information 255 is implementation specific and thus out of scope of this document. 257 The prefix information in PCEP-LS can also help in determining the 258 domain of the tunnel destination in the H-PCE (and ACTN) scenario. 259 Section 4.5 of [RFC6805] describe various mechanisms and procedures 260 that might be used, PCEP-LS provides a simple mechanism to exchange 261 this information within PCEP. 263 [RFC8453] defines three types of topology abstraction - (1) Native/ 264 White Topology; (2) Black Topology; and (3) Grey Topology. Based on 265 the local policy, the PNC (or child PCE) would share the domain 266 topology to the MDSC (or Parent PCE) based on the abstraction type. 267 The protocol extensions defined in this document can carry any type 268 of topology abstraction. 270 4. Requirements for PCEP extensions 272 Following key requirements associated with link-state (and TE) 273 distribution are identified for PCEP: 275 1. The PCEP speaker supporting this draft MUST have a mechanism to 276 advertise the Link-State (and TE) distribution capability. 278 2. PCC supporting this draft MUST have the capability to report the 279 link-state (and TE) information to the PCE. This MUST include 280 self originated (local) information and also allow remote 281 information learned via routing protocols. PCC MUST be capable 282 to do the initial bulk sync at the time of session initialization 283 as well as changes after. 285 3. A PCE MAY learn link-state (and TE) from PCEP as well as from 286 existing mechanisms like IGP/BGP-LS. PCEP extensions MUST have a 287 mechanism to link the information learned via other means. There 288 MUST NOT be any changes to the existing link-state (and TE) 289 population mechanism via IGP/BGP-LS. PCEP extension SHOULD keep 290 the properties in a protocol (IGP or BGP-LS) neutral way, such 291 that an implementation may not need to know about any OSPF or IS- 292 IS or BGP protocol specifics. 294 4. It SHOULD be possible to encode only the changes in link-state 295 (and TE) properties (after the initial sync) in PCEP messages. 296 This leads to faster convergence. 298 5. The same mechanism SHOULD be used for both MPLS TE as well as 299 GMPLS, optical and impairment aware properties. 301 6. The same mechanism SHOULD be used for PCE to PCE Link-state (and 302 TE) synchronization. 304 5. New Functions to distribute link-state (and TE) via PCEP 306 Several new functions are required in PCEP to support distribution of 307 link-state (and TE) information. A function can be initiated either 308 from a PCC towards a PCE (C-E) or from a PCE towards a PCC (E-C). 309 The new functions are: 311 o Capability advertisement (E-C,C-E): both the PCC and the PCE MUST 312 announce during PCEP session establishment that they support PCEP 313 extensions for distribution of link-state (and TE) information 314 defined in this document. 316 o Link-State (and TE) synchronization (C-E): after the session 317 between the PCC and a PCE is initialized, the PCE must learn Link- 318 State (and TE) information before it can perform path 319 computations. In case of stateful PCE it is RECOMMENDED that this 320 operation be done before LSP state synchronization. 322 o Link-State (and TE) Report (C-E): a PCC sends a LS (and TE) report 323 to a PCE whenever the Link-State and TE information changes. 325 6. Overview of Extensions to PCEP 327 6.1. New Messages 329 In this document, we define a new PCEP message called LS Report 330 (LSRpt), a PCEP message sent by a PCC to a PCE to report link-state 331 (and TE) information. Each LS Report in a LSRpt message can contain 332 the node or link properties. An unique PCEP specific LS identifier 333 (LS-ID) is also carried in the message to identify a node or link and 334 that remains constant for the lifetime of a PCEP session. This 335 identifier on its own is sufficient when no IGP or BGP-LS running in 336 the network for PCE to learn link-state (and TE) information. In 337 case PCE learns some information from PCEP and some from the existing 338 mechanism, the PCC SHOULD include the mapping of IGP or BGP-LS 339 identifier to map the information populated via PCEP with IGP/BGP-LS. 340 See Section 8.1 for details. 342 6.2. Capability Advertisement 344 During PCEP Initialization Phase, PCEP Speakers (PCE or PCC) 345 advertise their support of LS (and TE) distribution via PCEP 346 extensions. A PCEP Speaker includes the "LS Capability" TLV, 347 described in Section 9.2.1, in the OPEN Object to advertise its 348 support for PCEP-LS extensions. The presence of the LS Capability 349 TLV in PCC's OPEN Object indicates that the PCC is willing to send LS 350 Reports with local link-state (and TE) information. The presence of 351 the LS Capability TLV in PCE's Open message indicates that the PCE is 352 interested in receiving LS Reports with local link-state (and TE) 353 information. 355 The PCEP extensions for LS (and TE) distribution MUST NOT be used if 356 one or both PCEP Speakers have not included the LS Capability TLV in 357 their respective OPEN message. If the PCE that supports the 358 extensions of this draft but did not advertise this capability, then 359 upon receipt of a LSRpt message from the PCC, it SHOULD generate a 360 PCErr with error-type 19 (Invalid Operation), error-value TBD1 361 (Attempted LS Report if LS capability was not advertised) and it will 362 terminate the PCEP session. 364 The LS reports sent by PCC MAY carry the remote link-state (and TE) 365 information learned via existing means like IGP and BGP-LS only if 366 both PCEP Speakers set the R (remote) Flag in the "LS Capability" TLV 367 to 'Remote Allowed (R Flag = 1)'. If this is not the case and LS 368 reports carry remote link-state (and TE) information, then a PCErr 369 with error-type 19 (Invalid Operation) and error-value TBD1 370 (Attempted LS Report if LS remote capability was not advertised) and 371 it will terminate the PCEP session. 373 6.3. Initial Link-State (and TE) Synchronization 375 The purpose of LS Synchronization is to provide a checkpoint-in-time 376 state replica of a PCC's link-state (and TE) database in a PCE. 377 State Synchronization is performed immediately after the 378 Initialization phase (see [RFC5440]). In case of stateful PCE 379 ([RFC8231]) it is RECOMMENDED that the LS synchronization should be 380 done before LSP state synchronization. 382 During LS Synchronization, a PCC first takes a snapshot of the state 383 of its database, then sends the snapshot to a PCE in a sequence of LS 384 Reports. Each LS Report sent during LS Synchronization has the SYNC 385 Flag in the LS Object set to 1. The end of synchronization marker is 386 a LSRpt message with the SYNC Flag set to 0 for an LS Object with LS- 387 ID equal to the reserved value 0. If the PCC has no link-state to 388 synchronize, it will only send the end of synchronization marker. 390 Either the PCE or the PCC MAY terminate the session using the PCEP 391 session termination procedures during the synchronization phase. If 392 the session is terminated, the PCE MUST clean up state it received 393 from this PCC. The session re-establishment MUST be re-attempted per 394 the procedures defined in [RFC5440], including use of a back-off 395 timer. 397 If the PCC encounters a problem which prevents it from completing the 398 LS synchronization, it MUST send a PCErr message with error-type TBD2 399 (LS Synchronization Error) and error-value 2 (indicating an internal 400 PCC error) to the PCE and terminate the session. 402 The PCE does not send positive acknowledgments for properly received 403 LS synchronization messages. It MUST respond with a PCErr message 404 with error-type TBD2 (LS Synchronization Error) and error-value 1 405 (indicating an error in processing the LSRpt) if it encounters a 406 problem with the LS Report it received from the PCC and it MUST 407 terminate the session. 409 The LS reports can carry local as well as remote link-state (and TE) 410 information depending on the R flag in LS capability TLV. 412 The successful LS Synchronization sequence is shown in Figure 1. 414 +-+-+ +-+-+ 415 |PCC| |PCE| 416 +-+-+ +-+-+ 417 | | 418 |-----LSRpt, SYNC=1----->| (Sync start) 419 | | 420 |-----LSRpt, SYNC=1----->| 421 | . | 422 | . | 423 | . | 424 |-----LSRpt, SYNC=1----->| 425 | . | 426 | . | 427 | . | 428 | | 429 |-----LSRpt, SYNC=0----->| (End of sync marker 430 | | LS Report 431 | | for LS-ID=0) 432 | | (Sync done) 434 Figure 1: Successful LS synchronization 436 The sequence where the PCE fails during the LS Synchronization phase 437 is shown in Figure 2. 439 +-+-+ +-+-+ 440 |PCC| |PCE| 441 +-+-+ +-+-+ 442 | | 443 |-----LSRpt, SYNC=1----->| 444 | | 445 |-----LSRpt, SYNC=1----->| 446 | . | 447 | . | 448 | . | 449 |-----LSRpt, SYNC=1----->| 450 | | 451 |---LSRpt,SYNC=1 | 452 | \ ,-PCErr---| 453 | \ / | 454 | \/ | 455 | /\ | 456 | / `-------->| (Ignored) 457 |<--------` | 459 Figure 2: Failed LS synchronization (PCE failure) 461 The sequence where the PCC fails during the LS Synchronization phase 462 is shown in Figure 3. 464 +-+-+ +-+-+ 465 |PCC| |PCE| 466 +-+-+ +-+-+ 467 | | 468 |-----LSRpt, SYNC=1----->| 469 | | 470 |-----LSRpt, SYNC=1----->| 471 | . | 472 | . | 473 | . | 474 |-------- PCErr--------->| 475 | | 477 Figure 3: Failed LS synchronization (PCC failure) 479 6.3.1. Optimizations for LS Synchronization 481 These optimizations are described in 482 [I-D.kondreddy-pce-pcep-ls-sync-optimizations]. 484 6.4. LS Report 486 The PCC MUST report any changes in the link-state (and TE) 487 information to the PCE by sending a LS Report carried on a LSRpt 488 message to the PCE. Each node and Link would be uniquely identified 489 by a PCEP LS identifier (LS-ID). The LS reports may carry local as 490 well as remote link-state (and TE) information depending on the R 491 flag in LS capability TLV. In case R flag is set, it MAY also 492 include the mapping of IGP or BGP-LS identifier to map the 493 information populated via PCEP with IGP/BGP-LS identifiers. 495 More details about LSRpt message are in Section 8.1. 497 7. Transport 499 A permanent PCEP session (section 4.2.8 of [RFC5440]) MUST be 500 established between a PCE and PCC supporting link-state (and TE) 501 distribution via PCEP. In the case of session failure, session re- 502 establishment is re-attempted as per the procedures defined in 503 [RFC5440]. 505 8. PCEP Messages 507 As defined in [RFC5440], a PCEP message consists of a common header 508 followed by a variable-length body made of a set of objects that can 509 be either mandatory or optional. An object is said to be mandatory 510 in a PCEP message when the object must be included for the message to 511 be considered valid. For each PCEP message type, a set of rules is 512 defined that specify the set of objects that the message can carry. 513 An implementation MUST form the PCEP messages using the object 514 ordering specified in this document. 516 8.1. LS Report Message 518 A PCEP LS Report message (also referred to as LSRpt message) is a 519 PCEP message sent by a PCC to a PCE to report the link-state (and TE) 520 information. A LSRpt message can carry more than one LS Reports (LS 521 object). The Message-Type field of the PCEP common header for the 522 LSRpt message is set to [TBD3]. 524 The format of the LSRpt message is as follows: 526 ::= 527 528 Where: 530 ::= [] 532 The LS object is a mandatory object which carries LS information of a 533 node/prefix or a link. Each LS object has an unique LS-ID as 534 described in Section 9.3. If the LS object is missing, the receiving 535 PCE MUST send a PCErr message with Error-type=6 (Mandatory Object 536 missing) and Error-value=[TBD4] (LS object missing). 538 A PCE may choose to implement a limit on the LS information a single 539 PCC can populate. If a LSRpt is received that causes the PCE to 540 exceed this limit, it MUST send a PCErr message with error-type 19 541 (invalid operation) and error-value 4 (indicating resource limit 542 exceeded) in response to the LSRpt message triggering this condition 543 and SHOULD terminate the session. 545 8.2. The PCErr Message 547 If a PCEP speaker has advertised the LS capability on the PCEP 548 session, the PCErr message MAY include the LS object. If the error 549 reported is the result of an LS report, then the LS-ID number MUST be 550 the one from the LSRpt that triggered the error. 552 The format of a PCErr message from [RFC5440] is extended as follows: 554 ::= 555 ( [] ) | 556 [] 558 ::=[] 560 ::=[ | ] 561 563 ::=[] 565 ::=[] 567 ::=[] 569 9. Objects and TLV 571 The PCEP objects defined in this document are compliant with the PCEP 572 object format defined in [RFC5440]. The P flag and the I flag of the 573 PCEP objects defined in this document MUST always be set to 0 on 574 transmission and MUST be ignored on receipt since these flags are 575 exclusively related to path computation requests. 577 9.1. TLV Format 579 The TLV and the sub-TLV format (and padding) in this document, is as 580 per section 7.1 of [RFC5440]. 582 9.2. Open Object 584 This document defines a new optional TLV for use in the OPEN Object. 586 9.2.1. LS Capability TLV 588 The LS-CAPABILITY TLV is an optional TLV for use in the OPEN Object 589 for link-state (and TE) distribution via PCEP capability 590 advertisement. Its format is shown in the following figure: 592 0 1 2 3 593 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 1 594 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 595 | Type=[TBD5] | Length=4 | 596 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 597 | Flags |R| 598 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 599 The type of the TLV is [TBD5] and it has a fixed length of 4 octets. 601 The value comprises a single field - Flags (32 bits): 603 o R (remote allowed - 1 bit): if set to 1 by a PCC, the R Flag 604 indicates that the PCC allows reporting of remote LS information 605 learned via other means like IGP and BGP-LS; if set to 1 by a PCE, 606 the R Flag indicates that the PCE is capable of receiving remote 607 LS information (from the PCC point of view). The R Flag must be 608 advertised by both PCC and PCE for LSRpt messages to report remote 609 as well as local LS information on a PCEP session. The TLVs 610 related to IGP/BGP-LS identifier MUST be encoded when both PCEP 611 speakers have the R Flag set. 613 Unassigned bits are considered reserved. They MUST be set to 0 on 614 transmission and MUST be ignored on receipt. 616 Advertisement of the LS capability implies support of local link- 617 state (and TE) distribution, as well as the objects, TLVs and 618 procedures defined in this document. 620 9.3. LS Object 622 The LS (link-state) object MUST be carried within LSRpt messages and 623 MAY be carried within PCErr messages. The LS object contains a set 624 of fields used to specify the target node or link. It also contains 625 a flag indicating to a PCE that the LS synchronization is in 626 progress. The TLVs used with the LS object correlate with the IGP/ 627 BGP-LS encodings. 629 LS Object-Class is [TBD6]. 631 Four Object-Type values are defined for the LS object so far: 633 o LS Node: LS Object-Type is 1. 635 o LS Link: LS Object-Type is 2. 637 o LS IPv4 Topology Prefix: LS Object-Type is 3. 639 o LS IPv6 Topology Prefix: LS Object-Type is 4. 641 The format of all types of LS object is as follows: 643 0 1 2 3 644 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 1 645 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 646 | Protocol-ID | Flag |R|S| 647 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 648 | LS-ID | 649 | | 650 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 651 // TLVs // 652 | | 653 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 655 Protocol-ID (8-bit): The field provides the source information. The 656 protocol could be an IGP, BGP-LS or an abstraction algorithm. In 657 case PCC only provides local information of the PCC, it MUST use 658 Protocol-ID as Direct. The following values are defined (some of the 659 initial values are same as [RFC7752]): 661 +-------------+----------------------------------+ 662 | Protocol-ID | Source protocol | 663 +-------------+----------------------------------+ 664 | 1 | IS-IS Level 1 | 665 | 2 | IS-IS Level 2 | 666 | 3 | OSPFv2 | 667 | 4 | Direct | 668 | 5 | Static configuration | 669 | 6 | OSPFv3 | 670 | 7 | BGP | 671 | 8 | RSVP-TE | 672 | 9 | Segment Routing | 673 | 10 | PCEP | 674 | 11 | Abstraction | 675 +-------------+----------------------------------+ 677 Flags (24-bit): 679 o S (SYNC - 1 bit): the S Flag MUST be set to 1 on each LSRpt sent 680 from a PCC during LS Synchronization. The S Flag MUST be set to 0 681 in other LSRpt messages sent from the PCC. 683 o R (Remove - 1 bit): On LSRpt messages the R Flag indicates that 684 the node/link/prefix has been removed from the PCC and the PCE 685 SHOULD remove from its database. Upon receiving an LS Report with 686 the R Flag set to 1, the PCE SHOULD remove all state for the 687 node/link/prefix identified by the LS Identifiers from its 688 database. 690 LS-ID(64-bit): A PCEP-specific identifier for the node or link or 691 prefix information. A PCC creates an unique LS-ID for each 692 node/link/prefix that is constant for the lifetime of a PCEP session. 693 The PCC will advertise the same LS-ID on all PCEP sessions it 694 maintains at a given time. All subsequent PCEP messages then address 695 the node/link/prefix by the LS-ID. The values of 0 and 696 0xFFFFFFFFFFFFFFFF are reserved. 698 Unassigned bits are considered reserved. They MUST be set to 0 on 699 transmission and MUST be ignored on receipt. 701 TLVs that may be included in the LS Object are described in the 702 following sections. 704 9.3.1. Routing Universe TLV 706 In case of remote link-state (and TE) population when existing IGP/ 707 BGP-LS are also used, OSPF and IS-IS may run multiple routing 708 protocol instances over the same link as described in [RFC7752]. See 709 [RFC8202] and [RFC6549] for more information. These instances define 710 independent "routing universe". The 64-bit 'Identifier' field is 711 used to identify the "routing universe" where the LS object belongs. 712 The LS objects representing IGP objects (nodes or links or prefix) 713 from the same routing universe MUST have the same 'Identifier' value; 714 LS objects with different 'Identifier' values MUST be considered to 715 be from different routing universes. 717 The format of the optional ROUTING-UNIVERSE TLV is shown in the 718 following figure: 720 0 1 2 3 721 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 1 722 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 723 | Type=[TBD7] | Length=8 | 724 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 725 | Identifier | 726 | | 727 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 729 Below table lists the 'Identifier' values that are defined as well- 730 known in this draft (same as [RFC7752]). 732 +------------+-----------------------------------+ 733 | Identifier | Routing Universe | 734 +------------+-----------------------------------+ 735 | 0 | Default Layer 3 Routing topology | 736 +------------+-----------------------------------+ 738 If this TLV is not present the default value 0 is assumed. 740 9.3.2. Route Distinguisher TLV 742 To allow identification of VPN link, node and prefix information in 743 PCEP-LS, a Route Distinguisher (RD) [RFC4364] is used. The LS 744 objects from the same VPN MUST have the same RD; LS objects with 745 different RD values MUST be considered to be from different VPNs. 747 The ROUTE-DISTINGUISHER TLV is defined in 748 [I-D.ietf-pce-pcep-flowspec] as a Flow Specification TLVs with a 749 seperate registry. This document also adds the ROUTE-DISTINGUISHER 750 TLV with TBD15 in the PCEP TLV registry to be used inside the LS 751 object. 753 9.3.3. Virtual Network TLV 755 To realize ACTN, the MDSC needs to build an multi-domain topology. 756 This topology is best served, if this is an abstracted view of the 757 underlying network resources of each domain. It is also important to 758 provide a customer view of network slice for each customer. There is 759 a need to control the level of abstraction based on the deployment 760 scenario and business relationship between the controllers. 762 Virtual service coordination function in ACTN incorporates customer 763 service-related knowledge into the virtual network operations in 764 order to seamlessly operate virtual networks while meeting customer's 765 service requirements. [I-D.ietf-teas-actn-requirements] describes 766 various VN operations initiated by a customer/application. In this 767 context, there is a need for associating the abstracted link-state 768 and TE topology with a VN "construct" to facilitate VN operations in 769 PCE architecture. 771 VIRTUAL-NETWORK-TLV as per [I-D.ietf-pce-vn-association] can be 772 included in LS object to identify the link, node and prefix 773 information belongs to a particular VN. 775 9.3.4. Local Node Descriptors TLV 777 As described in [RFC7752], each link is anchored by a pair of Router- 778 IDs that are used by the underlying IGP, namely, 48-bit ISO System-ID 779 for IS-IS and 32 bit Router-ID for OSPFv2 and OSPFv3. In case of 780 additional auxiliary Router-IDs used for TE, these MUST also be 781 included in the link attribute TLV (see Section 9.3.9.2). 783 It is desirable that the Router-ID assignments inside the Node 784 Descriptor are globally unique. Some considerations for globally 785 unique Node/Link/Prefix identifiers are described in [RFC7752]. 787 The Local Node Descriptors TLV contains Node Descriptors for the node 788 anchoring the local end of the link. This TLV MUST be included in 789 the LS Report when during a given PCEP session a node/link/prefix is 790 first reported to a PCE. A PCC sends to a PCE the first LS Report 791 either during State Synchronization, or when a new node/link/prefix 792 is learned at the PCC. The value contains one or more Node 793 Descriptor Sub-TLVs, which allows specification of a flexible key for 794 any given node/link/prefix information such that global uniqueness of 795 the node/link/prefix is ensured. 797 This TLV is applicable for all LS Object-Type. 799 0 1 2 3 800 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 1 801 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 802 | Type=[TBD8] | Length | 803 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 804 | | 805 // Node Descriptor Sub-TLVs (variable) // 806 | | 807 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 809 The value contains one or more Node Descriptor Sub-TLVs defined in 810 Section 9.3.6. 812 9.3.5. Remote Node Descriptors TLV 814 The Remote Node Descriptors contains Node Descriptors for the node 815 anchoring the remote end of the link. This TLV MUST be included in 816 the LS Report when during a given PCEP session a link is first 817 reported to a PCE. A PCC sends to a PCE the first LS Report either 818 during State Synchronization, or when a new link is learned at the 819 PCC. The length of this TLV is variable. The value contains one or 820 more Node Descriptor Sub-TLVs defined in Section 9.3.6. 822 This TLV is applicable for LS Link Object-Type. 824 0 1 2 3 825 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 1 826 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 827 | Type=[TBD9] | Length | 828 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 829 | | 830 // Node Descriptor Sub-TLVs (variable) // 831 | | 832 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 834 9.3.6. Node Descriptors Sub-TLVs 836 The Node Descriptors TLV (Local and Remote) carries one or more Node 837 Descriptor Sub-TLV follows the format of all PCEP TLVs as defined in 838 [RFC5440], however, the Type values are selected from a new PCEP-LS 839 sub-TLV IANA registry (see Section 13.6). 841 Type values are chosen so that there can be commonality with BGP-LS 842 [RFC7752]. This is possible because the "BGP-LS Node Descriptor, 843 Link Descriptor, Prefix Descriptor, and Attribute TLVs" registry 844 marks 0-255 as reserved. Thus the space of the sub-TLV values for 845 the Type field can be partitioned as shown below - 847 Range | 848 ---------------+--------------------------------------------- 849 0 | Reserved - must not be allocated. 850 | 851 1 .. 255 | New PCEP sub-TLV allocated according to the 852 | registry defined in this document. 853 | 854 256 .. 65535 | Per BGP registry defined by [RFC7752]. 855 | Not to be allocated in this registry. 857 All Node Descriptors TLVs defined for BGP-LS can then be used with 858 PCEP-LS as well. One new PCEP sub-TLVs for Node Descriptor are 859 defined in this document. 861 +----------+-------------------+----------+----------------+ 862 | Sub-TLV | Description | Length |Value defined in| 863 +----------+-------------------+----------+----------------+ 864 | 1 | SPEAKER-ENTITY-ID | Variable | [RFC8232] | 865 +----------+-------------------+----------+----------------+ 867 A new sub-TLV type (1) is allocated for SPEAKER-ENTITY-ID sub-TLV. 868 The length and value field are as per [RFC8232]. 870 9.3.7. Link Descriptors TLV 872 The Link Descriptors TLV contains Link Descriptors for each link. 873 This TLV MUST be included in the LS Report when during a given PCEP 874 session a link is first reported to a PCE. A PCC sends to a PCE the 875 first LS Report either during State Synchronization, or when a new 876 link is learned at the PCC. The length of this TLV is variable. The 877 value contains one or more Link Descriptor Sub-TLVs. 879 The 'Link descriptor' TLVs uniquely identify a link among multiple 880 parallel links between a pair of anchor routers similar to [RFC7752]. 882 This TLV is applicable for LS Link Object-Type. 884 0 1 2 3 885 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 1 886 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 887 | Type=[TBD10] | Length | 888 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 889 | | 890 // Link Descriptor Sub-TLVs (variable) // 891 | | 892 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 894 All Link Descriptors TLVs defined for BGP-LS can then be used with 895 PCEP-LS as well. No new PCEP sub-TLVs for Link Descriptor are 896 defined in this document. 898 The format and semantics of the 'value' fields in most 'Link 899 Descriptor' sub-TLVs correspond to the format and semantics of value 900 fields in IS-IS Extended IS Reachability sub-TLVs, defined in 901 [RFC5305], [RFC5307] and [RFC6119]. Although the encodings for 'Link 902 Descriptor' TLVs were originally defined for IS-IS, the TLVs can 903 carry data sourced either by IS-IS or OSPF or direct. 905 The information about a link present in the LSA/LSP originated by the 906 local node of the link determines the set of sub-TLVs in the Link 907 Descriptor of the link as described in [RFC7752]. 909 9.3.8. Prefix Descriptors TLV 911 The Prefix Descriptors TLV contains Prefix Descriptors uniquely 912 identify an IPv4 or IPv6 Prefix originated by a Node. This TLV MUST 913 be included in the LS Report when during a given PCEP session a 914 prefix is first reported to a PCE. A PCC sends to a PCE the first LS 915 Report either during State Synchronization, or when a new prefix is 916 learned at the PCC. The length of this TLV is variable. 918 This TLV is applicable for LS Prefix Object-Types for both IPv4 and 919 IPv6. 921 0 1 2 3 922 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 1 923 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 924 | Type=[TBD11] | Length | 925 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 926 | | 927 // Prefix Descriptor Sub-TLVs (variable) // 928 | | 929 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 931 All Prefix Descriptors TLVs defined for BGP-LS can then be used with 932 PCEP-LS as well. No new PCEP sub-TLVs for Prefix Descriptor are 933 defined in this document. 935 9.3.9. PCEP-LS Attributes 937 9.3.9.1. Node Attributes TLV 939 This is an optional attribute that is used to carry node attributes. 940 This TLV is applicable for LS Node Object-Type. 942 0 1 2 3 943 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 1 944 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 945 | Type=[TBD12] | Length | 946 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 947 | | 948 // Node Attributes Sub-TLVs (variable) // 949 | | 950 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 952 All Node Attributes TLVs defined for BGP-LS can then be used with 953 PCEP-LS as well. No new PCEP sub-TLVs for Node Attributes are 954 defined in this document. 956 9.3.9.2. Link Attributes TLV 958 This TLV is applicable for LS Link Object-Type. The format and 959 semantics of the 'value' fields in some 'Link Attribute' sub-TLVs 960 correspond to the format and semantics of the 'value' fields in IS-IS 961 Extended IS Reachability sub-TLVs, defined in [RFC5305], [RFC5307] 962 and [RFC7752]. Although the encodings for 'Link Attribute' TLVs were 963 originally defined for IS-IS, the TLVs can carry data sourced either 964 by IS-IS or OSPF or direct. 966 0 1 2 3 967 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 1 968 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 969 | Type=[TBD13] | Length | 970 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 971 | | 972 // Link Attributes Sub-TLVs (variable) // 973 | | 974 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 976 All Link Attributes TLVs defined for BGP-LS can then be used with 977 PCEP-LS as well. No new PCEP sub-TLVs for Link Attributes are 978 defined in this document. 980 9.3.9.3. Prefix Attributes TLV 982 This TLV is applicable for LS Prefix Object-Types for both IPv4 and 983 IPv6. Prefixes are learned from the IGP (IS-IS or OSPF) or BGP 984 topology with a set of IGP attributes (such as metric, route tags, 985 etc.). This section describes the different attributes related to 986 the IPv4/IPv6 prefixes. Prefix Attributes TLVs SHOULD be encoded in 987 the LS Prefix Object. 989 0 1 2 3 990 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 1 991 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 992 | Type=[TBD14] | Length | 993 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 994 | | 995 // Prefix Attributes Sub-TLVs (variable) // 996 | | 997 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 999 All Prefix Attributes TLVs defined for BGP-LS can then be used with 1000 PCEP-LS as well. No new PCEP sub-TLVs for Prefix Attributes are 1001 defined in this document. 1003 9.3.10. Removal of an Attribute 1005 One of the key objective of PCEP-LS is to encode and carry only the 1006 impacted attributes of a Node, a Link or a Prefix. To accommodate 1007 this requirement, in case of a removal of an attribute, the sub-TLV 1008 MUST be included with no 'value' field and length=0 to indicate that 1009 the attribute is removed. On receiving a sub-TLV with zero length, 1010 the receiver removes the attribute from the database. An absence of 1011 a sub-TLV that was included earlier MUST be interpreted as no change. 1013 10. Other Considerations 1015 10.1. Inter-AS Links 1017 The main source of LS (and TE) information is the IGP, which is not 1018 active on inter-AS links. In some cases, the IGP may have 1019 information of inter-AS links ([RFC5392], [RFC5316]). In other 1020 cases, an implementation SHOULD provide a means to inject inter-AS 1021 links into PCEP. The exact mechanism used to provision the inter-AS 1022 links is outside the scope of this document. 1024 11. Security Considerations 1026 This document extends PCEP for LS (and TE) distribution including a 1027 new LSRpt message with a new object and TLVs. Procedures and 1028 protocol extensions defined in this document do not effect the 1029 overall PCEP security model. See [RFC5440], [RFC8253]. Tampering 1030 with the LSRpt message may have an effect on path computations at 1031 PCE. It also provides adversaries an opportunity to eavesdrop and 1032 learn sensitive information and plan sophisticated attacks on the 1033 network infrastructure. The PCE implementation SHOULD provide 1034 mechanisms to prevent strains created by network flaps and amount of 1035 LS (and TE) information. Thus it is suggested that any mechanism 1036 used for securing the transmission of other PCEP message be applied 1037 here as well. As a general precaution, it is RECOMMENDED that these 1038 PCEP extensions only be activated on authenticated and encrypted 1039 sessions belonging to the same administrative authority. 1041 Further, as stated in [RFC6952], PCEP implementations SHOULD support 1042 the TCP-AO [RFC5925] and not use TCP MD5 because of TCP MD5's known 1043 vulnerabilities and weakness. PCEP also support Transport Layer 1044 Security (TLS) [RFC8253] as per the recommendations and best current 1045 practices in [RFC7525]. 1047 12. Manageability Considerations 1049 All manageability requirements and considerations listed in [RFC5440] 1050 apply to PCEP protocol extensions defined in this document. In 1051 addition, requirements and considerations listed in this section 1052 apply. 1054 12.1. Control of Function and Policy 1056 A PCE or PCC implementation MUST allow configuring the PCEP-LS 1057 capabilities as described in this document. 1059 A PCC implementation SHOULD allow configuration to suggest if remote 1060 information learned via routing protocols should be reported or not. 1062 An implementation SHOULD allow the operator to specify the maximum 1063 number of LS data to be reported. 1065 An implementation SHOULD also allow the operator to create abstracted 1066 topologies that are reported to the peers and create different 1067 abstractions for different peers. 1069 An implementation SHOULD allow the operator to configure a 64-bit 1070 identifier for Routing Universe TLV. 1072 12.2. Information and Data Models 1074 An implementation SHOULD allow the operator to view the LS 1075 capabilities advertised by each peer. To serve this purpose, the 1076 PCEP YANG module [I-D.ietf-pce-pcep-yang] can be extended to include 1077 advertised capabilities. 1079 An implementation SHOULD also provide the statistics: 1081 o Total number of LSRpt sent/received, as well as per neighbour 1083 o Number of errors received for LSRpt, per neighbour 1085 o Total number of locally originated Link-State Information 1087 These statistics should be recorded as absolute counts since system 1088 or session start time. An implementation MAY also enhance this 1089 information by recording peak per-second counts in each case. 1091 An operator SHOULD define an import policy to limit inbound LSRpt to 1092 "drop all LSRpt from a particular peers" as well provide means to 1093 limit inbound LSRpts. 1095 12.3. Liveness Detection and Monitoring 1097 Mechanisms defined in this document do not imply any new liveness 1098 detection and monitoring requirements in addition to those already 1099 listed in [RFC5440]". 1101 12.4. Verify Correct Operations 1103 Mechanisms defined in this document do not imply any new operation 1104 verification requirements in addition to those already listed in 1105 [RFC5440] . 1107 12.5. Requirements On Other Protocols 1109 Mechanisms defined in this document do not imply any new requirements 1110 on other protocols. 1112 12.6. Impact On Network Operations 1114 Mechanisms defined in this document do not have any impact on network 1115 operations in addition to those already listed in [RFC5440]. 1117 13. IANA Considerations 1119 This document requests IANA actions to allocate code points for the 1120 protocol elements defined in this document. 1122 13.1. PCEP Messages 1124 IANA created a registry for "PCEP Messages". Each PCEP message has a 1125 message type value. This document defines a new PCEP message value. 1127 Value Meaning Reference 1128 TBD3 LSRpt [This I-D] 1130 13.2. PCEP Objects 1132 This document defines the following new PCEP Object-classes and 1133 Object-values: 1135 Object-Class Value Name Reference 1136 TBD6 LS Object [This I-D] 1137 Object-Type=1 1138 (LS Node) 1139 Object-Type=2 1140 (LS Link) 1141 Object-Type=3 1142 (LS IPv4 Prefix) 1143 Object-Type=4 1144 (LS IPv6 Prefix) 1146 13.3. LS Object 1148 This document requests that a new sub-registry, named "LS Object 1149 Protocol-ID Field", is created within the "Path Computation Element 1150 Protocol (PCEP) Numbers" registry to manage the Flag field of the LSP 1151 object. New values are to be assigned by Standards Action [RFC8126]. 1153 Value Meaning Reference 1154 0 Reserved [This I-D] 1155 1 IS-IS Level 1 [This I-D] 1156 2 IS-IS Level 2 [This I-D] 1157 3 OSPFv2 [This I-D] 1158 4 Direct [This I-D] 1159 5 Static configuration [This I-D] 1160 6 OSPFv3 [This I-D] 1161 7 BGP [This I-D] 1162 8 RSVP-TE [This I-D] 1163 9 Segment Routing [This I-D] 1164 10 PCEP [This I-D] 1165 11 Abstraction [This I-D] 1166 12-255 Unassigned 1168 Further, this document also requests that a new sub-registry, named 1169 "LS Object Flag Field", is created within the "Path Computation 1170 Element Protocol (PCEP) Numbers" registry to manage the Flag field of 1171 the LSP object.New values are to be assigned by Standards Action 1172 [RFC8126]. Each bit should be tracked with the following qualities: 1174 o Bit number (counting from bit 0 as the most significant bit) 1176 o Capability description 1178 o Defining RFC 1180 The following values are defined in this document: 1182 Bit Description Reference 1183 0-21 Unassigned 1184 22 R (Remove bit) [This I-D] 1185 23 S (Sync bit) [This I-D] 1187 13.4. PCEP-Error Object 1189 IANA is requested to make the following allocation in the "PCEP-ERROR 1190 Object Error Types and Values" registry. 1192 Error-Type Meaning Reference 1193 6 Mandatory Object missing [RFC5440] 1194 Error-Value=TBD4 [This I-D] 1195 (LS object missing) 1197 19 Invalid Operation [RFC8231] 1198 Error-Value=TBD1 [This I-D] 1199 (Attempted LS Report if LS 1200 remote capability was not 1201 advertised) 1203 TBD2 LS Synchronization Error [This I-D] 1204 Error-Value=1 1205 (An error in processing the 1206 LSRpt) 1207 Error-Value=2 1208 (An internal PCC error) 1210 13.5. PCEP TLV Type Indicators 1212 This document defines the following new PCEP TLVs. 1214 Value Meaning Reference 1215 TBD5 LS-CAPABILITY TLV [This I-D] 1216 TBD7 ROUTING-UNIVERSE TLV [This I-D] 1217 TBD15 ROUTE-DISTINGUISHER TLV [This I-D] 1218 TBD8 Local Node Descriptors TLV [This I-D] 1219 TBD9 Remote Node Descriptors TLV [This I-D] 1220 TBD10 Link Descriptors TLV [This I-D] 1221 TBD11 Prefix Descriptors TLV [This I-D] 1222 TBD12 Node Attributes TLV [This I-D] 1223 TBD13 Link Attributes TLV [This I-D] 1224 TBD14 Prefix Attributes TLV [This I-D] 1226 13.6. PCEP-LS Sub-TLV Type Indicators 1228 This document specifies the PCEP-LS Sub-TLVs. IANA is requested to 1229 create an "PCEP-LS Sub-TLV Types" sub-registry for the sub-TLVs 1230 carried in the PCEP-LS TLV (Local and Remote Node Descriptors TLV, 1231 Link Descriptors TLV, Prefix Descriptors TLV, Node Attributes TLV, 1232 Link Attributes TLV and Prefix Attributes TLV. 1234 Allocations from this registry are to be made according to the 1235 following assignment policies [RFC8126]: 1237 Range | Assignment policy 1238 ---------------+--------------------------------------------------- 1239 0 | Reserved - must not be allocated. 1240 | 1241 1 .. 251 | Specification Required 1242 | 1243 252 .. 255 | Experimental Use 1244 | 1245 256 .. 65535 | Reserved - must not be allocated. 1246 | Usage mirrors the BGP-LS TLV registry [RFC7752] 1247 | & [I-D.ietf-idr-flow-spec-v6]. 1249 IANA is requested to pre-populate this registry with values defined 1250 in this document as follows, taking the new values from the range 1 1251 to 251: 1253 Value | Meaning 1254 -------+------------------------ 1255 1 | SPEAKER-ENTITY-ID 1257 14. TLV Code Points Summary 1259 This section contains the global table of all TLVs in LS object 1260 defined in this document. 1262 +-----------+---------------------+---------------+-----------------+ 1263 | TLV | Description | Ref TLV | Value defined | 1264 | | | | in: | 1265 +-----------+---------------------+---------------+-----------------+ 1266 | TBD7 | Routing Universe | -- | Sec 9.2.1 | 1267 | TBD15 | Route | -- | Sec 9.2.2 | 1268 | | Distinguisher | | | 1269 | * | Virtual Network | -- | [ietf-pce- | 1270 | | | | vn-association] | 1271 | TBD8 | Local Node | 256 | [RFC7752] | 1272 | | Descriptors | | /3.2.1.2 | 1273 | TBD9 | Remote Node | 257 | [RFC7752] | 1274 | | Descriptors | | /3.2.1.3 | 1275 | TBD10 | Link Descriptors | -- | Sec 9.2.8 | 1276 | TBD11 | Prefix Descriptors | -- | Sec 9.2.9 | 1277 | TBD12 | Node Attributes | -- | Sec 9.2.10.1 | 1278 | TBD13 | Link Attributes | -- | Sec 9.2.10.2 | 1279 | TBD14 | Prefix Attributes | -- | Sec 9.2.10.3 | 1280 +-----------+---------------------+---------------+-----------------+ 1282 * this TLV is defined in a different PCEP document 1284 TLV Table 1286 15. Implementation Status 1288 The PCEP-LS protocol extensions as described in this I-D were 1289 implemented and tested for a variety of applications. Apart from the 1290 below implementation, there exist other experimental implementations 1291 done for optical networks. 1293 15.1. Hierarchical Transport PCE controllers 1295 The PCEP-LS has been implemented as part of IETF97 Hackathon and 1296 Bits-N-Bites demonstration. The use-case demonstrated was DCI use- 1297 case of ACTN architecture in which to show the following scenarios: 1299 - connectivity services on the ACTN based recursive hierarchical 1300 SDN/PCE platform that has the three tier level SDN controllers 1301 (two-tier level MDSC and PNC) on the top of the PTN systems 1302 managed by EMS. 1304 - Integration test of two tier-level MDSC: The SBI of the low 1305 level MDSC is the YANG based Korean national standards and the one 1306 of the high level MDSC the PCEP-LS based ACTN protocols. 1308 - Performance test of three types of SDN controller based recovery 1309 schemes including protection, reactive and proactive restoration. 1311 PCEP-LS protocol was used to demonstrate quick report of failed 1312 network components. 1314 15.2. ONOS-based Controller (MDSC and PNC) 1316 Huawei (PNC, MDSC) and SKT (MDSC) implemented PCEP-LS during 1317 Hackathon and IETF97 Bits-N-Bites demonstration. The demonstration 1318 was ONOS-based ACTN architecture in which to show the following 1319 capabilities: 1321 Both packet PNC and optical PNC (with optical PCEP-LS extensions) 1322 implemented PCEP-LS on its SBI as well as its NBI (towards MDSC). 1324 SKT orchestrator (acting as MDSC) also supported PCEP-LS (as well 1325 as RestConf) towards packet and optical PNCs on its SBI. 1327 Further description can be found at and the code at 1328 . 1330 16. Acknowledgments 1332 This document borrows some of the structure and text from the 1333 [RFC7752]. 1335 Thanks to Eric Wu, Venugopal Kondreddy, Mahendra Singh Negi, 1336 Avantika, and Zhengbin Li for the reviews. 1338 Thanks to Ramon Casellas for his comments and suggestions based on 1339 his implementation experience. 1341 17. References 1343 17.1. Normative References 1345 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1346 Requirement Levels", BCP 14, RFC 2119, 1347 DOI 10.17487/RFC2119, March 1997, 1348 . 1350 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 1351 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 1352 2008, . 1354 [RFC5307] Kompella, K., Ed. and Y. Rekhter, Ed., "IS-IS Extensions 1355 in Support of Generalized Multi-Protocol Label Switching 1356 (GMPLS)", RFC 5307, DOI 10.17487/RFC5307, October 2008, 1357 . 1359 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 1360 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 1361 DOI 10.17487/RFC5440, March 2009, 1362 . 1364 [RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic 1365 Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119, 1366 February 2011, . 1368 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 1369 S. Ray, "North-Bound Distribution of Link-State and 1370 Traffic Engineering (TE) Information Using BGP", RFC 7752, 1371 DOI 10.17487/RFC7752, March 2016, 1372 . 1374 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1375 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1376 May 2017, . 1378 [RFC8232] Crabbe, E., Minei, I., Medved, J., Varga, R., Zhang, X., 1379 and D. Dhody, "Optimizations of Label Switched Path State 1380 Synchronization Procedures for a Stateful PCE", RFC 8232, 1381 DOI 10.17487/RFC8232, September 2017, 1382 . 1384 17.2. Informative References 1386 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 1387 (TE) Extensions to OSPF Version 2", RFC 3630, 1388 DOI 10.17487/RFC3630, September 2003, 1389 . 1391 [RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in 1392 Support of Generalized Multi-Protocol Label Switching 1393 (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, 1394 . 1396 [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private 1397 Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February 1398 2006, . 1400 [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation 1401 Element (PCE)-Based Architecture", RFC 4655, 1402 DOI 10.17487/RFC4655, August 2006, 1403 . 1405 [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in 1406 Support of Inter-Autonomous System (AS) MPLS and GMPLS 1407 Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316, 1408 December 2008, . 1410 [RFC5392] Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in 1411 Support of Inter-Autonomous System (AS) MPLS and GMPLS 1412 Traffic Engineering", RFC 5392, DOI 10.17487/RFC5392, 1413 January 2009, . 1415 [RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP 1416 Authentication Option", RFC 5925, DOI 10.17487/RFC5925, 1417 June 2010, . 1419 [RFC6549] Lindem, A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi- 1420 Instance Extensions", RFC 6549, DOI 10.17487/RFC6549, 1421 March 2012, . 1423 [RFC6805] King, D., Ed. and A. Farrel, Ed., "The Application of the 1424 Path Computation Element Architecture to the Determination 1425 of a Sequence of Domains in MPLS and GMPLS", RFC 6805, 1426 DOI 10.17487/RFC6805, November 2012, 1427 . 1429 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 1430 BGP, LDP, PCEP, and MSDP Issues According to the Keying 1431 and Authentication for Routing Protocols (KARP) Design 1432 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 1433 . 1435 [RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, 1436 "Recommendations for Secure Use of Transport Layer 1437 Security (TLS) and Datagram Transport Layer Security 1438 (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May 1439 2015, . 1441 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1442 Writing an IANA Considerations Section in RFCs", BCP 26, 1443 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1444 . 1446 [RFC8202] Ginsberg, L., Previdi, S., and W. Henderickx, "IS-IS 1447 Multi-Instance", RFC 8202, DOI 10.17487/RFC8202, June 1448 2017, . 1450 [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path 1451 Computation Element Communication Protocol (PCEP) 1452 Extensions for Stateful PCE", RFC 8231, 1453 DOI 10.17487/RFC8231, September 2017, 1454 . 1456 [RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody, 1457 "PCEPS: Usage of TLS to Provide a Secure Transport for the 1458 Path Computation Element Communication Protocol (PCEP)", 1459 RFC 8253, DOI 10.17487/RFC8253, October 2017, 1460 . 1462 [RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path 1463 Computation Element Communication Protocol (PCEP) 1464 Extensions for PCE-Initiated LSP Setup in a Stateful PCE 1465 Model", RFC 8281, DOI 10.17487/RFC8281, December 2017, 1466 . 1468 [RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An 1469 Architecture for Use of PCE and the PCE Communication 1470 Protocol (PCEP) in a Network with Central Control", 1471 RFC 8283, DOI 10.17487/RFC8283, December 2017, 1472 . 1474 [RFC8453] Ceccarelli, D., Ed. and Y. Lee, Ed., "Framework for 1475 Abstraction and Control of TE Networks (ACTN)", RFC 8453, 1476 DOI 10.17487/RFC8453, August 2018, 1477 . 1479 [RFC8637] Dhody, D., Lee, Y., and D. Ceccarelli, "Applicability of 1480 the Path Computation Element (PCE) to the Abstraction and 1481 Control of TE Networks (ACTN)", RFC 8637, 1482 DOI 10.17487/RFC8637, July 2019, 1483 . 1485 [I-D.ietf-pce-pcep-yang] 1486 Dhody, D., Hardwick, J., Beeram, V., and J. Tantsura, "A 1487 YANG Data Model for Path Computation Element 1488 Communications Protocol (PCEP)", draft-ietf-pce-pcep- 1489 yang-13 (work in progress), October 2019. 1491 [I-D.ietf-teas-actn-requirements] 1492 Lee, Y., Ceccarelli, D., Miyasaka, T., Shin, J., and K. 1493 Lee, "Requirements for Abstraction and Control of TE 1494 Networks", draft-ietf-teas-actn-requirements-09 (work in 1495 progress), March 2018. 1497 [I-D.ietf-pce-pcep-flowspec] 1498 Dhody, D., Farrel, A., and Z. Li, "PCEP Extension for Flow 1499 Specification", draft-ietf-pce-pcep-flowspec-08 (work in 1500 progress), March 2020. 1502 [I-D.kondreddy-pce-pcep-ls-sync-optimizations] 1503 Kondreddy, V. and M. Negi, "Optimizations of PCEP Link- 1504 State(LS) Synchronization Procedures", draft-kondreddy- 1505 pce-pcep-ls-sync-optimizations-00 (work in progress), 1506 October 2015. 1508 [I-D.ietf-pce-vn-association] 1509 Lee, Y., Zheng, H., and D. Ceccarelli, "Path Computation 1510 Element communication Protocol (PCEP) extensions for 1511 Establishing Relationships between sets of LSPs and 1512 Virtual Networks", draft-ietf-pce-vn-association-01 (work 1513 in progress), October 2019. 1515 Appendix A. Examples 1517 These examples are for illustration purposes only to show how the new 1518 PCEP-LS message could be encoded. They are not meant to be an 1519 exhaustive list of all possible use cases and combinations. 1521 A.1. All Nodes 1523 Each node (PCC) in the network chooses to provide its own local node 1524 and link information, and in this way PCE can build the full link- 1525 state and TE information. 1527 +--------------------+ +--------------------+ 1528 | | | | 1529 | RTA |10.1.1.1 | RTB | 1530 | 1.1.1.1 |--------------------| 2.2.2.2 | 1531 | Area 0 | 10.1.1.2| Area 0 | 1532 | | | | 1533 +--------------------+ +--------------------+ 1534 RTA 1535 --- 1536 LS Node 1537 TLV - Local Node Descriptors 1538 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1539 Sub-TLV - 515: Router-ID: 1.1.1.1 1540 TLV - Node Attributes TLV 1541 Sub-TLV(s) 1543 LS Link 1544 TLV - Local Node Descriptors 1545 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1546 Sub-TLV - 515: Router-ID: 1.1.1.1 1547 TLV - Remote Node Descriptors 1548 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1549 Sub-TLV - 515: Router-ID: 2.2.2.2 1550 TLV - Link Descriptors 1551 Sub-TLV - 259: IPv4 interface: 10.1.1.1 1552 Sub-TLV - 260: IPv4 neighbor: 10.1.1.2 1553 TLV - Link Attributes TLV 1554 Sub-TLV(s) 1556 RTB 1557 --- 1558 LS Node 1559 TLV - Local Node Descriptors 1560 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1561 Sub-TLV - 515: Router-ID: 2.2.2.2 1563 TLV - Node Attributes TLV 1564 Sub-TLV(s) 1566 LS Link 1567 TLV - Local Node Descriptors 1568 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1569 Sub-TLV - 515: Router-ID: 2.2.2.2 1570 TLV - Remote Node Descriptors 1571 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1572 Sub-TLV - 515: Router-ID: 1.1.1.1 1573 TLV - Link Descriptors 1574 Sub-TLV - 259: IPv4 interface: 10.1.1.2 1575 Sub-TLV - 260: IPv4 neighbor: 10.1.1.1 1576 TLV - Link Attributes TLV 1577 Sub-TLV(s) 1579 A.2. Designated Node 1581 A designated node(s) in the network will provide its own local node 1582 as well as all learned remote information, and in this way PCE can 1583 build the full link-state and TE information. 1585 As described in Appendix A.1, the same LS Node and Link objects will 1586 be generated with a difference that it would be a designated router 1587 say RTA that generate all this information. 1589 A.3. Between PCEs 1591 As per Hierarchical-PCE [RFC6805], Parent PCE builds an abstract 1592 domain topology map with each domain as an abstract node and inter- 1593 domain links as an abstract link. Each child PCE may provide this 1594 information to the parent PCE. Considering the example in figure 1 1595 of [RFC6805], following LS object will be generated: 1597 PCE1 1598 ---- 1599 LS Node 1600 TLV - Local Node Descriptors 1601 Sub-TLV - 512: Autonomous System: 100 (Domain 1) 1602 Sub-TLV - 515: Router-ID: 11.11.11.11 (abstract) 1604 LS Link 1605 TLV - Local Node Descriptors 1606 Sub-TLV - 512: Autonomous System: 100 1607 Sub-TLV - 515: Router-ID: 11.11.11.11 (abstract) 1608 TLV - Remote Node Descriptors 1609 Sub-TLV - 512: Autonomous System: 200 (Domain 2) 1610 Sub-TLV - 515: Router-ID: 22.22.22.22 (abstract) 1611 TLV - Link Descriptors 1612 Sub-TLV - 259: IPv4 interface: 11.1.1.1 1613 Sub-TLV - 260: IPv4 neighbor: 11.1.1.2 1614 TLV - Link Attributes TLV 1615 Sub-TLV(s) 1617 LS Link 1618 TLV - Local Node Descriptors 1619 Sub-TLV - 512: Autonomous System: 100 1620 Sub-TLV - 515: Router-ID: 11.11.11.11 (abstract) 1621 TLV - Remote Node Descriptors 1622 Sub-TLV - 512: Autonomous System: 200 1623 Sub-TLV - 515: Router-ID: 22.22.22.22 (abstract) 1624 TLV - Link Descriptors 1625 Sub-TLV - 259: IPv4 interface: 12.1.1.1 1626 Sub-TLV - 260: IPv4 neighbor: 12.1.1.2 1627 TLV - Link Attributes TLV 1628 Sub-TLV(s) 1630 LS Link 1631 TLV - Local Node Descriptors 1632 Sub-TLV - 512: Autonomous System: 100 1633 Sub-TLV - 515: Router-ID: 11.11.11.11 (abstract) 1634 TLV - Remote Node Descriptors 1635 Sub-TLV - 512: Autonomous System: 400 (Domain 4) 1636 Sub-TLV - 515: Router-ID: 44.44.44.44 (abstract) 1637 TLV - Link Descriptors 1638 Sub-TLV - 259: IPv4 interface: 13.1.1.1 1639 Sub-TLV - 260: IPv4 neighbor: 13.1.1.2 1640 TLV - Link Attributes TLV 1641 Sub-TLV(s) 1643 * similar information will be generated by other PCE 1644 to help form the abstract domain topology. 1646 Further the exact border nodes and abstract internal path between the 1647 border nodes may also be transported to the Parent PCE to enable ACTN 1648 as described in [RFC8637] using the similar LS node and link objects 1649 encodings. 1651 Appendix B. Contributor Addresses 1653 Udayasree Palle 1655 EMail: udayasreereddy@gmail.com 1657 Sergio Belotti 1658 Nokia 1660 EMail: sergio.belotti@nokia.com 1662 Satish Karunanithi 1663 Huawei Technologies 1664 Divyashree Techno Park, Whitefield 1665 Bangalore, Karnataka 560066 1666 India 1668 Email: satishk@huawei.com 1670 Cheng Li 1671 Huawei Technologies 1672 Huawei Campus, No. 156 Beiqing Rd. 1673 Beijing 100095 1674 China 1676 Email: chengli13@huawei.com 1678 Authors' Addresses 1680 Dhruv Dhody 1681 Huawei Technologies 1682 Divyashree Techno Park, Whitefield 1683 Bangalore, Karnataka 560066 1684 India 1686 EMail: dhruv.ietf@gmail.com 1687 Shuping Peng 1688 Huawei Technologies 1689 Huawei Bld., No.156 Beiqing Rd. 1690 Beijing 100095 1691 China 1693 EMail: pengshuping@huawei.com 1695 Young Lee 1696 Samsung Electronics 1697 Seoul 1698 South Korea 1700 EMail: younglee.tx@gmail.com 1702 Daniele Ceccarelli 1703 Ericsson 1704 Torshamnsgatan,48 1705 Stockholm 1706 Sweden 1708 EMail: daniele.ceccarelli@ericsson.com