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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: January 15, 2021 Y. Lee 6 Samsung Electronics 7 D. Ceccarelli 8 Ericsson 9 A. Wang 10 China Telecom 11 July 14, 2020 13 PCEP extensions for Distribution of Link-State and TE Information 14 draft-dhodylee-pce-pcep-ls-17 16 Abstract 18 In order to compute and provide optimal paths, Path Computation 19 Elements (PCEs) require an accurate and timely Traffic Engineering 20 Database (TED). Traditionally this TED has been obtained from a link 21 state (LS) routing protocol supporting 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 January 15, 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 incremental update from each network node 170 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 mechanism 238 (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 a direct south bound interface 249 to all the nodes in the network. This enables operator to use 250 PCEP as single direct protocol between the controller and all the 251 nodes in the network. In this mode all nodes send only the local 252 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 scope of this document. 259 The prefix information in PCEP-LS can also help in determining the 260 domain of the tunnel destination in the H-PCE (and ACTN) scenario. 261 Section 4.5 of [RFC6805] describe various mechanisms and procedures 262 that might be used, PCEP-LS provides a simple mechanism to exchange 263 this information within PCEP. 265 [RFC8453] defines three types of topology abstraction - (1) Native/ 266 White Topology; (2) Black Topology; and (3) Grey Topology. Based on 267 the local policy, the PNC (or child PCE) would share the domain 268 topology to the MDSC (or Parent PCE) based on the abstraction type. 269 The protocol extensions defined in this document can carry any type 270 of topology abstraction. 272 4. Requirements for PCEP extensions 274 Following key requirements associated with link-state (and TE) 275 distribution are identified for PCEP: 277 1. The PCEP speaker supporting this draft MUST have a mechanism to 278 advertise the Link-State (and TE) distribution capability. 280 2. PCC supporting this draft MUST have the capability to report the 281 link-state (and TE) information to the PCE. This MUST include 282 self originated (local) information and also allow remote 283 information learned via routing protocols. PCC MUST be capable 284 to do the initial bulk sync at the time of session initialization 285 as well as changes after. 287 3. A PCE MAY learn link-state (and TE) from PCEP as well as from 288 existing mechanisms like IGP/BGP-LS. PCEP extensions MUST have a 289 mechanism to link the information learned via other means. There 290 MUST NOT be any changes to the existing link-state (and TE) 291 population mechanism via IGP/BGP-LS. PCEP extension SHOULD keep 292 the properties in a protocol (IGP or BGP-LS) neutral way, such 293 that an implementation may not need to know about any OSPF or IS- 294 IS or BGP protocol specifics. 296 4. It SHOULD be possible to encode only the changes in link-state 297 (and TE) properties (after the initial sync) in PCEP messages. 298 This leads to faster convergence. 300 5. The same mechanism SHOULD be used for both MPLS TE as well as 301 GMPLS, optical and impairment aware properties. 303 6. The same mechanism SHOULD be used for PCE to PCE Link-state (and 304 TE) synchronization. 306 5. New Functions to distribute link-state (and TE) via PCEP 308 Several new functions are required in PCEP to support distribution of 309 link-state (and TE) information. A function can be initiated either 310 from a PCC towards a PCE (C-E) or from a PCE towards a PCC (E-C). 311 The new functions are: 313 o Capability advertisement (E-C,C-E): both the PCC and the PCE MUST 314 announce during PCEP session establishment that they support PCEP 315 extensions for distribution of link-state (and TE) information 316 defined in this document. 318 o Link-State (and TE) synchronization (C-E): after the session 319 between the PCC and a PCE is initialized, the PCE must learn Link- 320 State (and TE) information before it can perform path 321 computations. In case of stateful PCE it is RECOMMENDED that this 322 operation be done before LSP state synchronization. 324 o Link-State (and TE) Report (C-E): a PCC sends a LS (and TE) report 325 to a PCE whenever the Link-State and TE information changes. 327 6. Overview of Extensions to PCEP 329 6.1. New Messages 331 In this document, we define a new PCEP message called LS Report 332 (LSRpt), a PCEP message sent by a PCC to a PCE to report link-state 333 (and TE) information. Each LS Report in a LSRpt message can contain 334 the node or link properties. An unique PCEP specific LS identifier 335 (LS-ID) is also carried in the message to identify a node or link and 336 that remains constant for the lifetime of a PCEP session. This 337 identifier on its own is sufficient when no IGP or BGP-LS running in 338 the network for PCE to learn link-state (and TE) information. In 339 case PCE learns some information from PCEP and some from the existing 340 mechanism, the PCC SHOULD include the mapping of IGP or BGP-LS 341 identifier to map the information populated via PCEP with IGP/BGP-LS. 342 See Section 8.1 for details. 344 6.2. Capability Advertisement 346 During PCEP Initialization Phase, PCEP Speakers (PCE or PCC) 347 advertise their support of LS (and TE) distribution via PCEP 348 extensions. A PCEP Speaker includes the "LS Capability" TLV, 349 described in Section 9.2.1, in the OPEN Object to advertise its 350 support for PCEP-LS extensions. The presence of the LS Capability 351 TLV in PCC's OPEN Object indicates that the PCC is willing to send LS 352 Reports with local link-state (and TE) information. The presence of 353 the LS Capability TLV in PCE's Open message indicates that the PCE is 354 interested in receiving LS Reports with local link-state (and TE) 355 information. 357 The PCEP extensions for LS (and TE) distribution MUST NOT be used if 358 one or both PCEP Speakers have not included the LS Capability TLV in 359 their respective OPEN message. If the PCE that supports the 360 extensions of this draft but did not advertise this capability, then 361 upon receipt of a LSRpt message from the PCC, it SHOULD generate a 362 PCErr with error-type 19 (Invalid Operation), error-value TBD1 363 (Attempted LS Report if LS capability was not advertised) and it will 364 terminate the PCEP session. 366 The LS reports sent by PCC MAY carry the remote link-state (and TE) 367 information learned via existing means like IGP and BGP-LS only if 368 both PCEP Speakers set the R (remote) Flag in the "LS Capability" TLV 369 to 'Remote Allowed (R Flag = 1)'. If this is not the case and LS 370 reports carry remote link-state (and TE) information, then a PCErr 371 with error-type 19 (Invalid Operation) and error-value TBD1 372 (Attempted LS Report if LS remote capability was not advertised) and 373 it will terminate the PCEP session. 375 6.3. Initial Link-State (and TE) Synchronization 377 The purpose of LS Synchronization is to provide a checkpoint-in-time 378 state replica of a PCC's link-state (and TE) database in a PCE. 379 State Synchronization is performed immediately after the 380 Initialization phase (see [RFC5440]). In case of stateful PCE 381 ([RFC8231]) it is RECOMMENDED that the LS synchronization should be 382 done before LSP state synchronization. 384 During LS Synchronization, a PCC first takes a snapshot of the state 385 of its database, then sends the snapshot to a PCE in a sequence of LS 386 Reports. Each LS Report sent during LS Synchronization has the SYNC 387 Flag in the LS Object set to 1. The end of synchronization marker is 388 a LSRpt message with the SYNC Flag set to 0 for an LS Object with LS- 389 ID equal to the reserved value 0. If the PCC has no link-state to 390 synchronize, it will only send the end of synchronization marker. 392 Either the PCE or the PCC MAY terminate the session using the PCEP 393 session termination procedures during the synchronization phase. If 394 the session is terminated, the PCE MUST clean up state it received 395 from this PCC. The session re-establishment MUST be re-attempted per 396 the procedures defined in [RFC5440], including use of a back-off 397 timer. 399 If the PCC encounters a problem which prevents it from completing the 400 LS synchronization, it MUST send a PCErr message with error-type TBD2 401 (LS Synchronization Error) and error-value 2 (indicating an internal 402 PCC error) to the PCE and terminate the session. 404 The PCE does not send positive acknowledgments for properly received 405 LS synchronization messages. It MUST respond with a PCErr message 406 with error-type TBD2 (LS Synchronization Error) and error-value 1 407 (indicating an error in processing the LSRpt) if it encounters a 408 problem with the LS Report it received from the PCC and it MUST 409 terminate the session. 411 The LS reports can carry local as well as remote link-state (and TE) 412 information depending on the R flag in LS capability TLV. 414 The successful LS Synchronization sequence is shown in Figure 1. 416 +-+-+ +-+-+ 417 |PCC| |PCE| 418 +-+-+ +-+-+ 419 | | 420 |-----LSRpt, SYNC=1----->| (Sync start) 421 | | 422 |-----LSRpt, SYNC=1----->| 423 | . | 424 | . | 425 | . | 426 |-----LSRpt, SYNC=1----->| 427 | . | 428 | . | 429 | . | 430 | | 431 |-----LSRpt, SYNC=0----->| (End of sync marker 432 | | LS Report 433 | | for LS-ID=0) 434 | | (Sync done) 436 Figure 1: Successful LS synchronization 438 The sequence where the PCE fails during the LS Synchronization phase 439 is shown in Figure 2. 441 +-+-+ +-+-+ 442 |PCC| |PCE| 443 +-+-+ +-+-+ 444 | | 445 |-----LSRpt, SYNC=1----->| 446 | | 447 |-----LSRpt, SYNC=1----->| 448 | . | 449 | . | 450 | . | 451 |-----LSRpt, SYNC=1----->| 452 | | 453 |---LSRpt,SYNC=1 | 454 | \ ,-PCErr---| 455 | \ / | 456 | \/ | 457 | /\ | 458 | / `-------->| (Ignored) 459 |<--------` | 461 Figure 2: Failed LS synchronization (PCE failure) 463 The sequence where the PCC fails during the LS Synchronization phase 464 is shown in Figure 3. 466 +-+-+ +-+-+ 467 |PCC| |PCE| 468 +-+-+ +-+-+ 469 | | 470 |-----LSRpt, SYNC=1----->| 471 | | 472 |-----LSRpt, SYNC=1----->| 473 | . | 474 | . | 475 | . | 476 |-------- PCErr--------->| 477 | | 479 Figure 3: Failed LS synchronization (PCC failure) 481 6.3.1. Optimizations for LS Synchronization 483 These optimizations are described in 484 [I-D.kondreddy-pce-pcep-ls-sync-optimizations]. 486 6.4. LS Report 488 The PCC MUST report any changes in the link-state (and TE) 489 information to the PCE by sending a LS Report carried on a LSRpt 490 message to the PCE. Each node and Link would be uniquely identified 491 by a PCEP LS identifier (LS-ID). The LS reports may carry local as 492 well as remote link-state (and TE) information depending on the R 493 flag in LS capability TLV. In case R flag is set, it MAY also 494 include the mapping of IGP or BGP-LS identifier to map the 495 information populated via PCEP with IGP/BGP-LS identifiers. 497 More details about LSRpt message are in Section 8.1. 499 7. Transport 501 A permanent PCEP session (section 4.2.8 of [RFC5440]) MUST be 502 established between a PCE and PCC supporting link-state (and TE) 503 distribution via PCEP. In the case of session failure, session re- 504 establishment is re-attempted as per the procedures defined in 505 [RFC5440]. 507 8. PCEP Messages 509 As defined in [RFC5440], a PCEP message consists of a common header 510 followed by a variable-length body made of a set of objects that can 511 be either mandatory or optional. An object is said to be mandatory 512 in a PCEP message when the object must be included for the message to 513 be considered valid. For each PCEP message type, a set of rules is 514 defined that specify the set of objects that the message can carry. 515 An implementation MUST form the PCEP messages using the object 516 ordering specified in this document. 518 8.1. LS Report Message 520 A PCEP LS Report message (also referred to as LSRpt message) is a 521 PCEP message sent by a PCC to a PCE to report the link-state (and TE) 522 information. A LSRpt message can carry more than one LS Reports (LS 523 object). The Message-Type field of the PCEP common header for the 524 LSRpt message is set to [TBD3]. 526 The format of the LSRpt message is as follows: 528 ::= 529 530 Where: 532 ::= [] 534 The LS object is a mandatory object which carries LS information of a 535 node/prefix or a link. Each LS object has an unique LS-ID as 536 described in Section 9.3. If the LS object is missing, the receiving 537 PCE MUST send a PCErr message with Error-type=6 (Mandatory Object 538 missing) and Error-value=[TBD4] (LS object missing). 540 A PCE may choose to implement a limit on the LS information a single 541 PCC can populate. If a LSRpt is received that causes the PCE to 542 exceed this limit, it MUST send a PCErr message with error-type 19 543 (invalid operation) and error-value 4 (indicating resource limit 544 exceeded) in response to the LSRpt message triggering this condition 545 and SHOULD terminate the session. 547 8.2. The PCErr Message 549 If a PCEP speaker has advertised the LS capability on the PCEP 550 session, the PCErr message MAY include the LS object. If the error 551 reported is the result of an LS report, then the LS-ID number MUST be 552 the one from the LSRpt that triggered the error. 554 The format of a PCErr message from [RFC5440] is extended as follows: 556 ::= 557 ( [] ) | 558 [] 560 ::=[] 562 ::=[ | ] 563 565 ::=[] 567 ::=[] 569 ::=[] 571 9. Objects and TLV 573 The PCEP objects defined in this document are compliant with the PCEP 574 object format defined in [RFC5440]. The P flag and the I flag of the 575 PCEP objects defined in this document MUST always be set to 0 on 576 transmission and MUST be ignored on receipt since these flags are 577 exclusively related to path computation requests. 579 9.1. TLV Format 581 The TLV and the sub-TLV format (and padding) in this document, is as 582 per section 7.1 of [RFC5440]. 584 9.2. Open Object 586 This document defines a new optional TLV for use in the OPEN Object. 588 9.2.1. LS Capability TLV 590 The LS-CAPABILITY TLV is an optional TLV for use in the OPEN Object 591 for link-state (and TE) distribution via PCEP capability 592 advertisement. Its format is shown in the following figure: 594 0 1 2 3 595 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 1 596 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 597 | Type=[TBD5] | Length=4 | 598 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 599 | Flags |R| 600 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 601 The type of the TLV is [TBD5] and it has a fixed length of 4 octets. 603 The value comprises a single field - Flags (32 bits): 605 o R (remote allowed - 1 bit): if set to 1 by a PCC, the R Flag 606 indicates that the PCC allows reporting of remote LS information 607 learned via other means like IGP and BGP-LS; if set to 1 by a PCE, 608 the R Flag indicates that the PCE is capable of receiving remote 609 LS information (from the PCC point of view). The R Flag must be 610 advertised by both PCC and PCE for LSRpt messages to report remote 611 as well as local LS information on a PCEP session. The TLVs 612 related to IGP/BGP-LS identifier MUST be encoded when both PCEP 613 speakers have the R Flag set. 615 Unassigned bits are considered reserved. They MUST be set to 0 on 616 transmission and MUST be ignored on receipt. 618 Advertisement of the LS capability implies support of local link- 619 state (and TE) distribution, as well as the objects, TLVs and 620 procedures defined in this document. 622 9.3. LS Object 624 The LS (link-state) object MUST be carried within LSRpt messages and 625 MAY be carried within PCErr messages. The LS object contains a set 626 of fields used to specify the target node or link. It also contains 627 a flag indicating to a PCE that the LS synchronization is in 628 progress. The TLVs used with the LS object correlate with the IGP/ 629 BGP-LS encodings. 631 LS Object-Class is TBD6. 633 Four Object-Type values are defined for the LS object so far: 635 o LS Node: LS Object-Type is 1. 637 o LS Link: LS Object-Type is 2. 639 o LS IPv4 Topology Prefix: LS Object-Type is 3. 641 o LS IPv6 Topology Prefix: LS Object-Type is 4. 643 The format of all types of LS object is as follows: 645 0 1 2 3 646 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 1 647 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 648 | Protocol-ID | Flag |R|S| 649 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 650 | LS-ID | 651 | | 652 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 653 // TLVs // 654 | | 655 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 657 Protocol-ID (8-bit): The field provides the source information. The 658 protocol could be an IGP, BGP-LS or an abstraction algorithm. In 659 case PCC only provides local information of the PCC, it MUST use 660 Protocol-ID as Direct. The following values are defined (some of the 661 initial values are same as [I-D.ietf-idr-rfc7752bis]): 663 +-------------+----------------------------------+ 664 | Protocol-ID | Source protocol | 665 +-------------+----------------------------------+ 666 | 1 | IS-IS Level 1 | 667 | 2 | IS-IS Level 2 | 668 | 3 | OSPFv2 | 669 | 4 | Direct | 670 | 5 | Static configuration | 671 | 6 | OSPFv3 | 672 | 7 | BGP | 673 | 8 | RSVP-TE | 674 | 9 | Segment Routing | 675 | 10 | PCEP | 676 | 11 | Abstraction | 677 +-------------+----------------------------------+ 679 Flags (24-bit): 681 o S (SYNC - 1 bit): the S Flag MUST be set to 1 on each LSRpt sent 682 from a PCC during LS Synchronization. The S Flag MUST be set to 0 683 in other LSRpt messages sent from the PCC. 685 o R (Remove - 1 bit): On LSRpt messages the R Flag indicates that 686 the node/link/prefix has been removed from the PCC and the PCE 687 SHOULD remove from its database. Upon receiving an LS Report with 688 the R Flag set to 1, the PCE SHOULD remove all state for the 689 node/link/prefix identified by the LS Identifiers from its 690 database. 692 LS-ID(64-bit): A PCEP-specific identifier for the node or link or 693 prefix information. A PCC creates an unique LS-ID for each 694 node/link/prefix that is constant for the lifetime of a PCEP session. 695 The PCC will advertise the same LS-ID on all PCEP sessions it 696 maintains at a given time. All subsequent PCEP messages then address 697 the node/link/prefix by the LS-ID. The values of 0 and 698 0xFFFFFFFFFFFFFFFF are reserved. 700 Unassigned bits are considered reserved. They MUST be set to 0 on 701 transmission and MUST be ignored on receipt. 703 TLVs that may be included in the LS Object are described in the 704 following sections. 706 9.3.1. Routing Universe TLV 708 In case of remote link-state (and TE) population when existing IGP/ 709 BGP-LS are also used, OSPF and IS-IS may run multiple routing 710 protocol instances over the same link as described in 711 [I-D.ietf-idr-rfc7752bis]. See [RFC8202] and [RFC6549] for more 712 information. These instances define independent "routing universe". 713 The 64-bit 'Identifier' field is used to identify the "routing 714 universe" where the LS object belongs. The LS objects representing 715 IGP objects (nodes or links or prefix) from the same routing universe 716 MUST have the same 'Identifier' value; LS objects with different 717 'Identifier' values MUST be considered to be from different routing 718 universes. 720 The format of the optional ROUTING-UNIVERSE TLV is shown in the 721 following figure: 723 0 1 2 3 724 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 1 725 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 726 | Type=[TBD7] | Length=8 | 727 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 728 | Identifier | 729 | | 730 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 732 Below table lists the 'Identifier' values that are defined as well- 733 known in this draft (same as [I-D.ietf-idr-rfc7752bis]). 735 +------------+-----------------------------------+ 736 | Identifier | Routing Universe | 737 +------------+-----------------------------------+ 738 | 0 | Default Layer 3 Routing topology | 739 +------------+-----------------------------------+ 741 If this TLV is not present the default value 0 is assumed. 743 9.3.2. Route Distinguisher TLV 745 To allow identification of VPN link, node and prefix information in 746 PCEP-LS, a Route Distinguisher (RD) [RFC4364] is used. The LS 747 objects from the same VPN MUST have the same RD; LS objects with 748 different RD values MUST be considered to be from different VPNs. 750 The ROUTE-DISTINGUISHER TLV is defined in 751 [I-D.ietf-pce-pcep-flowspec] as a Flow Specification TLVs with a 752 seperate registry. This document also adds the ROUTE-DISTINGUISHER 753 TLV with TBD15 in the PCEP TLV registry to be used inside the LS 754 object. 756 9.3.3. Virtual Network TLV 758 To realize ACTN, the MDSC needs to build an multi-domain topology. 759 This topology is best served, if this is an abstracted view of the 760 underlying network resources of each domain. It is also important to 761 provide a customer view of network slice for each customer. There is 762 a need to control the level of abstraction based on the deployment 763 scenario and business relationship between the controllers. 765 Virtual service coordination function in ACTN incorporates customer 766 service-related knowledge into the virtual network operations in 767 order to seamlessly operate virtual networks while meeting customer's 768 service requirements. [I-D.ietf-teas-actn-requirements] describes 769 various VN operations initiated by a customer/application. In this 770 context, there is a need for associating the abstracted link-state 771 and TE topology with a VN "construct" to facilitate VN operations in 772 PCE architecture. 774 VIRTUAL-NETWORK-TLV as per [I-D.ietf-pce-vn-association] can be 775 included in LS object to identify the link, node and prefix 776 information belongs to a particular VN. 778 9.3.4. Local Node Descriptors TLV 780 As described in [I-D.ietf-idr-rfc7752bis], each link is anchored by a 781 pair of Router-IDs that are used by the underlying IGP, namely, 782 48-bit ISO System-ID for IS-IS and 32 bit Router-ID for OSPFv2 and 783 OSPFv3. In case of additional auxiliary Router-IDs used for TE, 784 these MUST also be included in the link attribute TLV (see 785 Section 9.3.9.2). 787 It is desirable that the Router-ID assignments inside the Node 788 Descriptor are globally unique. Some considerations for globally 789 unique Node/Link/Prefix identifiers are described in 790 [I-D.ietf-idr-rfc7752bis]. 792 The Local Node Descriptors TLV contains Node Descriptors for the node 793 anchoring the local end of the link. This TLV MUST be included in 794 the LS Report when during a given PCEP session a node/link/prefix is 795 first reported to a PCE. A PCC sends to a PCE the first LS Report 796 either during State Synchronization, or when a new node/link/prefix 797 is learned at the PCC. The value contains one or more Node 798 Descriptor Sub-TLVs, which allows specification of a flexible key for 799 any given node/link/prefix information such that global uniqueness of 800 the node/link/prefix is ensured. 802 This TLV is applicable for all LS Object-Type. 804 0 1 2 3 805 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 1 806 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 807 | Type=[TBD8] | Length | 808 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 809 | | 810 // Node Descriptor Sub-TLVs (variable) // 811 | | 812 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 814 The value contains one or more Node Descriptor Sub-TLVs defined in 815 Section 9.3.6. 817 9.3.5. Remote Node Descriptors TLV 819 The Remote Node Descriptors contains Node Descriptors for the node 820 anchoring the remote end of the link. This TLV MUST be included in 821 the LS Report when during a given PCEP session a link is first 822 reported to a PCE. A PCC sends to a PCE the first LS Report either 823 during State Synchronization, or when a new link is learned at the 824 PCC. The length of this TLV is variable. The value contains one or 825 more Node Descriptor Sub-TLVs defined in Section 9.3.6. 827 This TLV is applicable for LS Link Object-Type. 829 0 1 2 3 830 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 1 831 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 832 | Type=[TBD9] | Length | 833 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 834 | | 835 // Node Descriptor Sub-TLVs (variable) // 836 | | 837 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 839 9.3.6. Node Descriptors Sub-TLVs 841 The Node Descriptors TLV (Local and Remote) carries one or more Node 842 Descriptor Sub-TLV follows the format of all PCEP TLVs as defined in 843 [RFC5440], however, the Type values are selected from a new PCEP-LS 844 sub-TLV IANA registry (see Section 13.6). 846 Type values are chosen so that there can be commonality with BGP-LS 847 [I-D.ietf-idr-rfc7752bis]. This is possible because the "BGP-LS Node 848 Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs" 849 registry marks 0-255 as reserved. Thus the space of the sub-TLV 850 values for the Type field can be partitioned as shown below - 852 Range | 853 ---------------+--------------------------------------------- 854 0 | Reserved - must not be allocated. 855 | 856 1 .. 255 | New PCEP sub-TLV allocated according to the 857 | registry defined in this document. 858 | 859 256 .. 65535 | Per BGP registry defined by 860 | [I-D.ietf-idr-rfc7752bis]. 861 | Not to be allocated in this registry. 863 All Node Descriptors TLVs defined for BGP-LS can then be used with 864 PCEP-LS as well. One new PCEP sub-TLVs for Node Descriptor are 865 defined in this document. 867 +----------+-------------------+----------+----------------+ 868 | Sub-TLV | Description | Length |Value defined in| 869 +----------+-------------------+----------+----------------+ 870 | 1 | SPEAKER-ENTITY-ID | Variable | [RFC8232] | 871 +----------+-------------------+----------+----------------+ 873 A new sub-TLV type (1) is allocated for SPEAKER-ENTITY-ID sub-TLV. 874 The length and value field are as per [RFC8232]. 876 9.3.7. Link Descriptors TLV 878 The Link Descriptors TLV contains Link Descriptors for each link. 879 This TLV MUST be included in the LS Report when during a given PCEP 880 session a link is first reported to a PCE. A PCC sends to a PCE the 881 first LS Report either during State Synchronization, or when a new 882 link is learned at the PCC. The length of this TLV is variable. The 883 value contains one or more Link Descriptor Sub-TLVs. 885 The 'Link descriptor' TLVs uniquely identify a link among multiple 886 parallel links between a pair of anchor routers similar to 887 [I-D.ietf-idr-rfc7752bis]. 889 This TLV is applicable for LS Link Object-Type. 891 0 1 2 3 892 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 1 893 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 894 | Type=[TBD10] | Length | 895 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 896 | | 897 // Link Descriptor Sub-TLVs (variable) // 898 | | 899 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 901 All Link Descriptors TLVs defined for BGP-LS can then be used with 902 PCEP-LS as well. No new PCEP sub-TLVs for Link Descriptor are 903 defined in this document. 905 The format and semantics of the 'value' fields in most 'Link 906 Descriptor' sub-TLVs correspond to the format and semantics of value 907 fields in IS-IS Extended IS Reachability sub-TLVs, defined in 908 [RFC5305], [RFC5307] and [RFC6119]. Although the encodings for 'Link 909 Descriptor' TLVs were originally defined for IS-IS, the TLVs can 910 carry data sourced either by IS-IS or OSPF or direct. 912 The information about a link present in the LSA/LSP originated by the 913 local node of the link determines the set of sub-TLVs in the Link 914 Descriptor of the link as described in [I-D.ietf-idr-rfc7752bis]. 916 9.3.8. Prefix Descriptors TLV 918 The Prefix Descriptors TLV contains Prefix Descriptors uniquely 919 identify an IPv4 or IPv6 Prefix originated by a Node. This TLV MUST 920 be included in the LS Report when during a given PCEP session a 921 prefix is first reported to a PCE. A PCC sends to a PCE the first LS 922 Report either during State Synchronization, or when a new prefix is 923 learned at the PCC. The length of this TLV is variable. 925 This TLV is applicable for LS Prefix Object-Types for both IPv4 and 926 IPv6. 928 0 1 2 3 929 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 1 930 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 931 | Type=[TBD11] | Length | 932 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 933 | | 934 // Prefix Descriptor Sub-TLVs (variable) // 935 | | 936 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 938 All Prefix Descriptors TLVs defined for BGP-LS can then be used with 939 PCEP-LS as well. No new PCEP sub-TLVs for Prefix Descriptor are 940 defined in this document. 942 9.3.9. PCEP-LS Attributes 944 9.3.9.1. Node Attributes TLV 946 This is an optional attribute that is used to carry node attributes. 947 This TLV is applicable for LS Node Object-Type. 949 0 1 2 3 950 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 1 951 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 952 | Type=[TBD12] | Length | 953 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 954 | | 955 // Node Attributes Sub-TLVs (variable) // 956 | | 957 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 959 All Node Attributes TLVs defined for BGP-LS can then be used with 960 PCEP-LS as well. No new PCEP sub-TLVs for Node Attributes are 961 defined in this document. 963 9.3.9.2. Link Attributes TLV 965 This TLV is applicable for LS Link Object-Type. The format and 966 semantics of the 'value' fields in some 'Link Attribute' sub-TLVs 967 correspond to the format and semantics of the 'value' fields in IS-IS 968 Extended IS Reachability sub-TLVs, defined in [RFC5305], [RFC5307] 969 and [I-D.ietf-idr-rfc7752bis]. Although the encodings for 'Link 970 Attribute' TLVs were originally defined for IS-IS, the TLVs can carry 971 data sourced either by IS-IS or OSPF or direct. 973 0 1 2 3 974 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 1 975 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 976 | Type=[TBD13] | Length | 977 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 978 | | 979 // Link Attributes Sub-TLVs (variable) // 980 | | 981 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 983 All Link Attributes TLVs defined for BGP-LS can then be used with 984 PCEP-LS as well. No new PCEP sub-TLVs for Link Attributes are 985 defined in this document. 987 9.3.9.3. Prefix Attributes TLV 989 This TLV is applicable for LS Prefix Object-Types for both IPv4 and 990 IPv6. Prefixes are learned from the IGP (IS-IS or OSPF) or BGP 991 topology with a set of IGP attributes (such as metric, route tags, 992 etc.). This section describes the different attributes related to 993 the IPv4/IPv6 prefixes. Prefix Attributes TLVs SHOULD be encoded in 994 the LS Prefix Object. 996 0 1 2 3 997 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 1 998 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 999 | Type=[TBD14] | Length | 1000 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1001 | | 1002 // Prefix Attributes Sub-TLVs (variable) // 1003 | | 1004 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1006 All Prefix Attributes TLVs defined for BGP-LS can then be used with 1007 PCEP-LS as well. No new PCEP sub-TLVs for Prefix Attributes are 1008 defined in this document. 1010 9.3.10. Removal of an Attribute 1012 One of the key objective of PCEP-LS is to encode and carry only the 1013 impacted attributes of a Node, a Link or a Prefix. To accommodate 1014 this requirement, in case of a removal of an attribute, the sub-TLV 1015 MUST be included with no 'value' field and length=0 to indicate that 1016 the attribute is removed. On receiving a sub-TLV with zero length, 1017 the receiver removes the attribute from the database. An absence of 1018 a sub-TLV that was included earlier MUST be interpreted as no change. 1020 10. Other Considerations 1022 10.1. Inter-AS Links 1024 The main source of LS (and TE) information is the IGP, which is not 1025 active on inter-AS links. In some cases, the IGP may have 1026 information of inter-AS links ([RFC5392], [RFC5316]). In other 1027 cases, an implementation SHOULD provide a means to inject inter-AS 1028 links into PCEP. The exact mechanism used to provision the inter-AS 1029 links is outside the scope of this document. 1031 11. Security Considerations 1033 This document extends PCEP for LS (and TE) distribution including a 1034 new LSRpt message with a new object and TLVs. Procedures and 1035 protocol extensions defined in this document do not effect the 1036 overall PCEP security model. See [RFC5440], [RFC8253]. Tampering 1037 with the LSRpt message may have an effect on path computations at 1038 PCE. It also provides adversaries an opportunity to eavesdrop and 1039 learn sensitive information and plan sophisticated attacks on the 1040 network infrastructure. The PCE implementation SHOULD provide 1041 mechanisms to prevent strains created by network flaps and amount of 1042 LS (and TE) information. Thus it is suggested that any mechanism 1043 used for securing the transmission of other PCEP message be applied 1044 here as well. As a general precaution, it is RECOMMENDED that these 1045 PCEP extensions only be activated on authenticated and encrypted 1046 sessions belonging to the same administrative authority. 1048 Further, as stated in [RFC6952], PCEP implementations SHOULD support 1049 the TCP-AO [RFC5925] and not use TCP MD5 because of TCP MD5's known 1050 vulnerabilities and weakness. PCEP also support Transport Layer 1051 Security (TLS) [RFC8253] as per the recommendations and best current 1052 practices in [RFC7525]. 1054 12. Manageability Considerations 1056 All manageability requirements and considerations listed in [RFC5440] 1057 apply to PCEP protocol extensions defined in this document. In 1058 addition, requirements and considerations listed in this section 1059 apply. 1061 12.1. Control of Function and Policy 1063 A PCE or PCC implementation MUST allow configuring the PCEP-LS 1064 capabilities as described in this document. 1066 A PCC implementation SHOULD allow configuration to suggest if remote 1067 information learned via routing protocols should be reported or not. 1069 An implementation SHOULD allow the operator to specify the maximum 1070 number of LS data to be reported. 1072 An implementation SHOULD also allow the operator to create abstracted 1073 topologies that are reported to the peers and create different 1074 abstractions for different peers. 1076 An implementation SHOULD allow the operator to configure a 64-bit 1077 identifier for Routing Universe TLV. 1079 12.2. Information and Data Models 1081 An implementation SHOULD allow the operator to view the LS 1082 capabilities advertised by each peer. To serve this purpose, the 1083 PCEP YANG module [I-D.ietf-pce-pcep-yang] can be extended to include 1084 advertised capabilities. 1086 An implementation SHOULD also provide the statistics: 1088 o Total number of LSRpt sent/received, as well as per neighbour 1090 o Number of errors received for LSRpt, per neighbour 1092 o Total number of locally originated Link-State Information 1094 These statistics should be recorded as absolute counts since system 1095 or session start time. An implementation MAY also enhance this 1096 information by recording peak per-second counts in each case. 1098 An operator SHOULD define an import policy to limit inbound LSRpt to 1099 "drop all LSRpt from a particular peers" as well provide means to 1100 limit inbound LSRpts. 1102 12.3. Liveness Detection and Monitoring 1104 Mechanisms defined in this document do not imply any new liveness 1105 detection and monitoring requirements in addition to those already 1106 listed in [RFC5440]". 1108 12.4. Verify Correct Operations 1110 Mechanisms defined in this document do not imply any new operation 1111 verification requirements in addition to those already listed in 1112 [RFC5440] . 1114 12.5. Requirements On Other Protocols 1116 Mechanisms defined in this document do not imply any new requirements 1117 on other protocols. 1119 12.6. Impact On Network Operations 1121 Mechanisms defined in this document do not have any impact on network 1122 operations in addition to those already listed in [RFC5440]. 1124 13. IANA Considerations 1126 This document requests IANA actions to allocate code points for the 1127 protocol elements defined in this document. 1129 13.1. PCEP Messages 1131 IANA created a registry for "PCEP Messages". Each PCEP message has a 1132 message type value. This document defines a new PCEP message value. 1134 Value Meaning Reference 1135 TBD3 LSRpt [This I-D] 1137 13.2. PCEP Objects 1139 This document defines the following new PCEP Object-classes and 1140 Object-values: 1142 Object-Class Value Name Reference 1143 TBD6 LS Object [This I-D] 1144 Object-Type=1 1145 (LS Node) 1146 Object-Type=2 1147 (LS Link) 1148 Object-Type=3 1149 (LS IPv4 Prefix) 1150 Object-Type=4 1151 (LS IPv6 Prefix) 1153 13.3. LS Object 1155 This document requests that a new sub-registry, named "LS Object 1156 Protocol-ID Field", is created within the "Path Computation Element 1157 Protocol (PCEP) Numbers" registry to manage the Flag field of the LSP 1158 object. New values are to be assigned by Standards Action [RFC8126]. 1160 Value Meaning Reference 1161 0 Reserved [This I-D] 1162 1 IS-IS Level 1 [This I-D] 1163 2 IS-IS Level 2 [This I-D] 1164 3 OSPFv2 [This I-D] 1165 4 Direct [This I-D] 1166 5 Static configuration [This I-D] 1167 6 OSPFv3 [This I-D] 1168 7 BGP [This I-D] 1169 8 RSVP-TE [This I-D] 1170 9 Segment Routing [This I-D] 1171 10 PCEP [This I-D] 1172 11 Abstraction [This I-D] 1173 12-255 Unassigned 1175 Further, this document also requests that a new sub-registry, named 1176 "LS Object Flag Field", is created within the "Path Computation 1177 Element Protocol (PCEP) Numbers" registry to manage the Flag field of 1178 the LSP object.New values are to be assigned by Standards Action 1179 [RFC8126]. Each bit should be tracked with the following qualities: 1181 o Bit number (counting from bit 0 as the most significant bit) 1183 o Capability description 1185 o Defining RFC 1187 The following values are defined in this document: 1189 Bit Description Reference 1190 0-21 Unassigned 1191 22 R (Remove bit) [This I-D] 1192 23 S (Sync bit) [This I-D] 1194 13.4. PCEP-Error Object 1196 IANA is requested to make the following allocation in the "PCEP-ERROR 1197 Object Error Types and Values" registry. 1199 Error-Type Meaning Reference 1200 6 Mandatory Object missing [RFC5440] 1201 Error-Value=TBD4 [This I-D] 1202 (LS object missing) 1204 19 Invalid Operation [RFC8231] 1205 Error-Value=TBD1 [This I-D] 1206 (Attempted LS Report if LS 1207 remote capability was not 1208 advertised) 1210 TBD2 LS Synchronization Error [This I-D] 1211 Error-Value=1 1212 (An error in processing the 1213 LSRpt) 1214 Error-Value=2 1215 (An internal PCC error) 1217 13.5. PCEP TLV Type Indicators 1219 This document defines the following new PCEP TLVs. 1221 Value Meaning Reference 1222 TBD5 LS-CAPABILITY TLV [This I-D] 1223 TBD7 ROUTING-UNIVERSE TLV [This I-D] 1224 TBD15 ROUTE-DISTINGUISHER TLV [This I-D] 1225 TBD8 Local Node Descriptors TLV [This I-D] 1226 TBD9 Remote Node Descriptors TLV [This I-D] 1227 TBD10 Link Descriptors TLV [This I-D] 1228 TBD11 Prefix Descriptors TLV [This I-D] 1229 TBD12 Node Attributes TLV [This I-D] 1230 TBD13 Link Attributes TLV [This I-D] 1231 TBD14 Prefix Attributes TLV [This I-D] 1233 13.6. PCEP-LS Sub-TLV Type Indicators 1235 This document specifies the PCEP-LS Sub-TLVs. IANA is requested to 1236 create an "PCEP-LS Sub-TLV Types" sub-registry for the sub-TLVs 1237 carried in the PCEP-LS TLV (Local and Remote Node Descriptors TLV, 1238 Link Descriptors TLV, Prefix Descriptors TLV, Node Attributes TLV, 1239 Link Attributes TLV and Prefix Attributes TLV. 1241 Allocations from this registry are to be made according to the 1242 following assignment policies [RFC8126]: 1244 Range | Assignment policy 1245 ---------------+--------------------------------------------------- 1246 0 | Reserved - must not be allocated. 1247 | 1248 1 .. 251 | Specification Required 1249 | 1250 252 .. 255 | Experimental Use 1251 | 1252 256 .. 65535 | Reserved - must not be allocated. 1253 | Usage mirrors the BGP-LS TLV registry 1254 | [I-D.ietf-idr-rfc7752bis] 1255 | 1257 IANA is requested to pre-populate this registry with values defined 1258 in this document as follows, taking the new values from the range 1 1259 to 251: 1261 Value | Meaning 1262 -------+------------------------ 1263 1 | SPEAKER-ENTITY-ID 1265 14. TLV Code Points Summary 1267 This section contains the global table of all TLVs in LS object 1268 defined in this document. 1270 +-----------+---------------------+---------------+-----------------+ 1271 | TLV | Description | Ref TLV | Value defined | 1272 | | | | in: | 1273 +-----------+---------------------+---------------+-----------------+ 1274 | TBD7 | Routing Universe | -- | Sec 9.2.1 | 1275 | TBD15 | Route | -- | Sec 9.2.2 | 1276 | | Distinguisher | | | 1277 | * | Virtual Network | -- | [ietf-pce- | 1278 | | | | vn-association] | 1279 | TBD8 | Local Node | 256 | [I-D.ietf-idr- | 1280 | | | | rfc7752bis] | 1281 | | Descriptors | | /3.2.1.2 | 1282 | TBD9 | Remote Node | 257 | [I-D.ietf-idr- | 1283 | | | | rfc7752bis] | 1284 | | Descriptors | | /3.2.1.3 | 1285 | TBD10 | Link Descriptors | -- | Sec 9.2.8 | 1286 | TBD11 | Prefix Descriptors | -- | Sec 9.2.9 | 1287 | TBD12 | Node Attributes | -- | Sec 9.2.10.1 | 1288 | TBD13 | Link Attributes | -- | Sec 9.2.10.2 | 1289 | TBD14 | Prefix Attributes | -- | Sec 9.2.10.3 | 1290 +-----------+---------------------+---------------+-----------------+ 1292 * this TLV is defined in a different PCEP document 1294 TLV Table 1296 15. Implementation Status 1298 The PCEP-LS protocol extensions as described in this I-D were 1299 implemented and tested for a variety of applications. Apart from the 1300 below implementation, there exist other experimental implementations 1301 done for optical networks. 1303 15.1. Hierarchical Transport PCE controllers 1305 The PCEP-LS has been implemented as part of IETF97 Hackathon and 1306 Bits-N-Bites demonstration. The use-case demonstrated was DCI use- 1307 case of ACTN architecture in which to show the following scenarios: 1309 - connectivity services on the ACTN based recursive hierarchical 1310 SDN/PCE platform that has the three tier level SDN controllers 1311 (two-tier level MDSC and PNC) on the top of the PTN systems 1312 managed by EMS. 1314 - Integration test of two tier-level MDSC: The SBI of the low 1315 level MDSC is the YANG based Korean national standards and the one 1316 of the high level MDSC the PCEP-LS based ACTN protocols. 1318 - Performance test of three types of SDN controller based recovery 1319 schemes including protection, reactive and proactive restoration. 1320 PCEP-LS protocol was used to demonstrate quick report of failed 1321 network components. 1323 15.2. ONOS-based Controller (MDSC and PNC) 1325 Huawei (PNC, MDSC) and SKT (MDSC) implemented PCEP-LS during 1326 Hackathon and IETF97 Bits-N-Bites demonstration. The demonstration 1327 was ONOS-based ACTN architecture in which to show the following 1328 capabilities: 1330 Both packet PNC and optical PNC (with optical PCEP-LS extensions) 1331 implemented PCEP-LS on its SBI as well as its NBI (towards MDSC). 1333 SKT orchestrator (acting as MDSC) also supported PCEP-LS (as well 1334 as RestConf) towards packet and optical PNCs on its SBI. 1336 Further description can be found at and the code at 1337 . 1339 16. Acknowledgments 1341 This document borrows some of the structure and text from the 1342 [I-D.ietf-idr-rfc7752bis]. 1344 Thanks to Eric Wu, Venugopal Kondreddy, Mahendra Singh Negi, 1345 Avantika, and Zhengbin Li for the reviews. 1347 Thanks to Ramon Casellas for his comments and suggestions based on 1348 his implementation experience. 1350 17. References 1352 17.1. Normative References 1354 [I-D.ietf-idr-rfc7752bis] 1355 Talaulikar, K., "Distribution of Link-State and Traffic 1356 Engineering Information Using BGP", draft-ietf-idr- 1357 rfc7752bis-03 (work in progress), March 2020. 1359 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1360 Requirement Levels", BCP 14, RFC 2119, 1361 DOI 10.17487/RFC2119, March 1997, 1362 . 1364 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 1365 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 1366 2008, . 1368 [RFC5307] Kompella, K., Ed. and Y. Rekhter, Ed., "IS-IS Extensions 1369 in Support of Generalized Multi-Protocol Label Switching 1370 (GMPLS)", RFC 5307, DOI 10.17487/RFC5307, October 2008, 1371 . 1373 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 1374 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 1375 DOI 10.17487/RFC5440, March 2009, 1376 . 1378 [RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic 1379 Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119, 1380 February 2011, . 1382 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1383 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1384 May 2017, . 1386 [RFC8232] Crabbe, E., Minei, I., Medved, J., Varga, R., Zhang, X., 1387 and D. Dhody, "Optimizations of Label Switched Path State 1388 Synchronization Procedures for a Stateful PCE", RFC 8232, 1389 DOI 10.17487/RFC8232, September 2017, 1390 . 1392 17.2. Informative References 1394 [I-D.ietf-pce-pcep-flowspec] 1395 Dhody, D., Farrel, A., and Z. Li, "PCEP Extension for Flow 1396 Specification", draft-ietf-pce-pcep-flowspec-09 (work in 1397 progress), June 2020. 1399 [I-D.ietf-pce-pcep-yang] 1400 Dhody, D., Hardwick, J., Beeram, V., and J. Tantsura, "A 1401 YANG Data Model for Path Computation Element 1402 Communications Protocol (PCEP)", draft-ietf-pce-pcep- 1403 yang-14 (work in progress), July 2020. 1405 [I-D.ietf-pce-vn-association] 1406 Lee, Y., Zheng, H., and D. Ceccarelli, "Path Computation 1407 Element communication Protocol (PCEP) extensions for 1408 Establishing Relationships between sets of LSPs and 1409 Virtual Networks", draft-ietf-pce-vn-association-02 (work 1410 in progress), April 2020. 1412 [I-D.ietf-teas-actn-requirements] 1413 Lee, Y., Ceccarelli, D., Miyasaka, T., Shin, J., and K. 1414 Lee, "Requirements for Abstraction and Control of TE 1415 Networks", draft-ietf-teas-actn-requirements-09 (work in 1416 progress), March 2018. 1418 [I-D.kondreddy-pce-pcep-ls-sync-optimizations] 1419 Kondreddy, V. and M. Negi, "Optimizations of PCEP Link- 1420 State(LS) Synchronization Procedures", draft-kondreddy- 1421 pce-pcep-ls-sync-optimizations-00 (work in progress), 1422 October 2015. 1424 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 1425 (TE) Extensions to OSPF Version 2", RFC 3630, 1426 DOI 10.17487/RFC3630, September 2003, 1427 . 1429 [RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in 1430 Support of Generalized Multi-Protocol Label Switching 1431 (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, 1432 . 1434 [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private 1435 Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February 1436 2006, . 1438 [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation 1439 Element (PCE)-Based Architecture", RFC 4655, 1440 DOI 10.17487/RFC4655, August 2006, 1441 . 1443 [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in 1444 Support of Inter-Autonomous System (AS) MPLS and GMPLS 1445 Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316, 1446 December 2008, . 1448 [RFC5392] Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in 1449 Support of Inter-Autonomous System (AS) MPLS and GMPLS 1450 Traffic Engineering", RFC 5392, DOI 10.17487/RFC5392, 1451 January 2009, . 1453 [RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP 1454 Authentication Option", RFC 5925, DOI 10.17487/RFC5925, 1455 June 2010, . 1457 [RFC6549] Lindem, A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi- 1458 Instance Extensions", RFC 6549, DOI 10.17487/RFC6549, 1459 March 2012, . 1461 [RFC6805] King, D., Ed. and A. Farrel, Ed., "The Application of the 1462 Path Computation Element Architecture to the Determination 1463 of a Sequence of Domains in MPLS and GMPLS", RFC 6805, 1464 DOI 10.17487/RFC6805, November 2012, 1465 . 1467 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 1468 BGP, LDP, PCEP, and MSDP Issues According to the Keying 1469 and Authentication for Routing Protocols (KARP) Design 1470 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 1471 . 1473 [RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, 1474 "Recommendations for Secure Use of Transport Layer 1475 Security (TLS) and Datagram Transport Layer Security 1476 (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May 1477 2015, . 1479 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1480 Writing an IANA Considerations Section in RFCs", BCP 26, 1481 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1482 . 1484 [RFC8202] Ginsberg, L., Previdi, S., and W. Henderickx, "IS-IS 1485 Multi-Instance", RFC 8202, DOI 10.17487/RFC8202, June 1486 2017, . 1488 [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path 1489 Computation Element Communication Protocol (PCEP) 1490 Extensions for Stateful PCE", RFC 8231, 1491 DOI 10.17487/RFC8231, September 2017, 1492 . 1494 [RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody, 1495 "PCEPS: Usage of TLS to Provide a Secure Transport for the 1496 Path Computation Element Communication Protocol (PCEP)", 1497 RFC 8253, DOI 10.17487/RFC8253, October 2017, 1498 . 1500 [RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path 1501 Computation Element Communication Protocol (PCEP) 1502 Extensions for PCE-Initiated LSP Setup in a Stateful PCE 1503 Model", RFC 8281, DOI 10.17487/RFC8281, December 2017, 1504 . 1506 [RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An 1507 Architecture for Use of PCE and the PCE Communication 1508 Protocol (PCEP) in a Network with Central Control", 1509 RFC 8283, DOI 10.17487/RFC8283, December 2017, 1510 . 1512 [RFC8453] Ceccarelli, D., Ed. and Y. Lee, Ed., "Framework for 1513 Abstraction and Control of TE Networks (ACTN)", RFC 8453, 1514 DOI 10.17487/RFC8453, August 2018, 1515 . 1517 [RFC8637] Dhody, D., Lee, Y., and D. Ceccarelli, "Applicability of 1518 the Path Computation Element (PCE) to the Abstraction and 1519 Control of TE Networks (ACTN)", RFC 8637, 1520 DOI 10.17487/RFC8637, July 2019, 1521 . 1523 Appendix A. Examples 1525 These examples are for illustration purposes only to show how the new 1526 PCEP-LS message could be encoded. They are not meant to be an 1527 exhaustive list of all possible use cases and combinations. 1529 A.1. All Nodes 1531 Each node (PCC) in the network chooses to provide its own local node 1532 and link information, and in this way PCE can build the full link- 1533 state and TE information. 1535 +--------------------+ +--------------------+ 1536 | | | | 1537 | RTA |10.1.1.1 | RTB | 1538 | 1.1.1.1 |--------------------| 2.2.2.2 | 1539 | Area 0 | 10.1.1.2| Area 0 | 1540 | | | | 1541 +--------------------+ +--------------------+ 1542 RTA 1543 --- 1544 LS Node 1545 TLV - Local Node Descriptors 1546 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1547 Sub-TLV - 515: Router-ID: 1.1.1.1 1548 TLV - Node Attributes TLV 1549 Sub-TLV(s) 1551 LS Link 1552 TLV - Local Node Descriptors 1553 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1554 Sub-TLV - 515: Router-ID: 1.1.1.1 1555 TLV - Remote Node Descriptors 1556 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1557 Sub-TLV - 515: Router-ID: 2.2.2.2 1558 TLV - Link Descriptors 1559 Sub-TLV - 259: IPv4 interface: 10.1.1.1 1560 Sub-TLV - 260: IPv4 neighbor: 10.1.1.2 1561 TLV - Link Attributes TLV 1562 Sub-TLV(s) 1564 RTB 1565 --- 1566 LS Node 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 1571 TLV - Node Attributes TLV 1572 Sub-TLV(s) 1574 LS Link 1575 TLV - Local Node Descriptors 1576 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1577 Sub-TLV - 515: Router-ID: 2.2.2.2 1578 TLV - Remote Node Descriptors 1579 Sub-TLV - 514: OSPF Area-ID: 0.0.0.0 1580 Sub-TLV - 515: Router-ID: 1.1.1.1 1581 TLV - Link Descriptors 1582 Sub-TLV - 259: IPv4 interface: 10.1.1.2 1583 Sub-TLV - 260: IPv4 neighbor: 10.1.1.1 1584 TLV - Link Attributes TLV 1585 Sub-TLV(s) 1587 A.2. Designated Node 1589 A designated node(s) in the network will provide its own local node 1590 as well as all learned remote information, and in this way PCE can 1591 build the full link-state and TE information. 1593 As described in Appendix A.1, the same LS Node and Link objects will 1594 be generated with a difference that it would be a designated router 1595 say RTA that generate all this information. 1597 A.3. Between PCEs 1599 As per Hierarchical-PCE [RFC6805], Parent PCE builds an abstract 1600 domain topology map with each domain as an abstract node and inter- 1601 domain links as an abstract link. Each child PCE may provide this 1602 information to the parent PCE. Considering the example in figure 1 1603 of [RFC6805], following LS object will be generated: 1605 PCE1 1606 ---- 1607 LS Node 1608 TLV - Local Node Descriptors 1609 Sub-TLV - 512: Autonomous System: 100 (Domain 1) 1610 Sub-TLV - 515: Router-ID: 11.11.11.11 (abstract) 1612 LS Link 1613 TLV - Local Node Descriptors 1614 Sub-TLV - 512: Autonomous System: 100 1615 Sub-TLV - 515: Router-ID: 11.11.11.11 (abstract) 1616 TLV - Remote Node Descriptors 1617 Sub-TLV - 512: Autonomous System: 200 (Domain 2) 1618 Sub-TLV - 515: Router-ID: 22.22.22.22 (abstract) 1619 TLV - Link Descriptors 1620 Sub-TLV - 259: IPv4 interface: 11.1.1.1 1621 Sub-TLV - 260: IPv4 neighbor: 11.1.1.2 1622 TLV - Link Attributes TLV 1623 Sub-TLV(s) 1625 LS Link 1626 TLV - Local Node Descriptors 1627 Sub-TLV - 512: Autonomous System: 100 1628 Sub-TLV - 515: Router-ID: 11.11.11.11 (abstract) 1629 TLV - Remote Node Descriptors 1630 Sub-TLV - 512: Autonomous System: 200 1631 Sub-TLV - 515: Router-ID: 22.22.22.22 (abstract) 1632 TLV - Link Descriptors 1633 Sub-TLV - 259: IPv4 interface: 12.1.1.1 1634 Sub-TLV - 260: IPv4 neighbor: 12.1.1.2 1635 TLV - Link Attributes TLV 1636 Sub-TLV(s) 1638 LS Link 1639 TLV - Local Node Descriptors 1640 Sub-TLV - 512: Autonomous System: 100 1641 Sub-TLV - 515: Router-ID: 11.11.11.11 (abstract) 1642 TLV - Remote Node Descriptors 1643 Sub-TLV - 512: Autonomous System: 400 (Domain 4) 1644 Sub-TLV - 515: Router-ID: 44.44.44.44 (abstract) 1645 TLV - Link Descriptors 1646 Sub-TLV - 259: IPv4 interface: 13.1.1.1 1647 Sub-TLV - 260: IPv4 neighbor: 13.1.1.2 1648 TLV - Link Attributes TLV 1649 Sub-TLV(s) 1651 * similar information will be generated by other PCE 1652 to help form the abstract domain topology. 1654 Further the exact border nodes and abstract internal path between the 1655 border nodes may also be transported to the Parent PCE to enable ACTN 1656 as described in [RFC8637] using the similar LS node and link objects 1657 encodings. 1659 Appendix B. Contributor Addresses 1661 Udayasree Palle 1663 EMail: udayasreereddy@gmail.com 1665 Sergio Belotti 1666 Nokia 1668 EMail: sergio.belotti@nokia.com 1670 Satish Karunanithi 1671 Huawei Technologies 1672 Divyashree Techno Park, Whitefield 1673 Bangalore, Karnataka 560066 1674 India 1676 Email: satishk@huawei.com 1678 Cheng Li 1679 Huawei Technologies 1680 Huawei Campus, No. 156 Beiqing Rd. 1681 Beijing 100095 1682 China 1684 Email: c.l@huawei.com 1686 Authors' Addresses 1688 Dhruv Dhody 1689 Huawei Technologies 1690 Divyashree Techno Park, Whitefield 1691 Bangalore, Karnataka 560066 1692 India 1694 EMail: dhruv.ietf@gmail.com 1695 Shuping Peng 1696 Huawei Technologies 1697 Huawei Bld., No.156 Beiqing Rd. 1698 Beijing 100095 1699 China 1701 EMail: pengshuping@huawei.com 1703 Young Lee 1704 Samsung Electronics 1705 Seoul 1706 South Korea 1708 EMail: younglee.tx@gmail.com 1710 Daniele Ceccarelli 1711 Ericsson 1712 Torshamnsgatan,48 1713 Stockholm 1714 Sweden 1716 EMail: daniele.ceccarelli@ericsson.com 1718 Aijun Wang 1719 China Telecom 1720 Beiqijia Town, Changping District 1721 Beijing, Beijing 102209 1722 China 1724 EMail: wangaj3@chinatelecom.cn