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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 7525 (Obsoleted by RFC 9325) == Outdated reference: A later version (-28) exists of draft-ietf-spring-srv6-network-programming-24 == Outdated reference: A later version (-22) exists of draft-ietf-spring-segment-routing-policy-08 == Outdated reference: A later version (-14) exists of draft-ietf-pce-pcep-extension-for-pce-controller-07 == Outdated reference: A later version (-23) exists of draft-ietf-pce-pcep-yang-14 Summary: 1 error (**), 0 flaws (~~), 5 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 PCE Working Group S. Sivabalan 3 Internet-Draft Ciena Corporation 4 Intended status: Standards Track C. Filsfils 5 Expires: May 4, 2021 Cisco Systems, Inc. 6 J. Tantsura 7 Apstra, Inc. 8 J. Hardwick 9 Metaswitch Networks 10 S. Previdi 11 C. Li 12 Huawei Technologies 13 October 31, 2020 15 Carrying Binding Label/Segment-ID in PCE-based Networks. 16 draft-ietf-pce-binding-label-sid-05 18 Abstract 20 In order to provide greater scalability, network opacity, and service 21 independence, Segment Routing (SR) utilizes a Binding Segment 22 Identifier (BSID). It is possible to associate a BSID to RSVP-TE 23 signaled Traffic Engineering Label Switching Path or binding Segment- 24 ID (SID) to SR Traffic Engineering path. Such a binding label/SID 25 can be used by an upstream node for steering traffic into the 26 appropriate TE path to enforce SR policies. This document proposes 27 an approach for reporting binding label/SID to Path Computation 28 Element (PCE) for supporting PCE-based Traffic Engineering policies. 30 Requirements Language 32 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 33 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 34 "OPTIONAL" in this document are to be interpreted as described in BCP 35 14 [RFC2119] [RFC8174] when, and only when, they appear in all 36 capitals, as shown here. 38 Status of This Memo 40 This Internet-Draft is submitted in full conformance with the 41 provisions of BCP 78 and BCP 79. 43 Internet-Drafts are working documents of the Internet Engineering 44 Task Force (IETF). Note that other groups may also distribute 45 working documents as Internet-Drafts. The list of current Internet- 46 Drafts is at https://datatracker.ietf.org/drafts/current/. 48 Internet-Drafts are draft documents valid for a maximum of six months 49 and may be updated, replaced, or obsoleted by other documents at any 50 time. It is inappropriate to use Internet-Drafts as reference 51 material or to cite them other than as "work in progress." 53 This Internet-Draft will expire on May 4, 2021. 55 Copyright Notice 57 Copyright (c) 2020 IETF Trust and the persons identified as the 58 document authors. All rights reserved. 60 This document is subject to BCP 78 and the IETF Trust's Legal 61 Provisions Relating to IETF Documents 62 (https://trustee.ietf.org/license-info) in effect on the date of 63 publication of this document. Please review these documents 64 carefully, as they describe your rights and restrictions with respect 65 to this document. Code Components extracted from this document must 66 include Simplified BSD License text as described in Section 4.e of 67 the Trust Legal Provisions and are provided without warranty as 68 described in the Simplified BSD License. 70 Table of Contents 72 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 73 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 74 3. Path Binding TLV . . . . . . . . . . . . . . . . . . . . . . 6 75 3.1. SRv6 Endpoint Behavior and SID Structure . . . . . . . . 7 76 4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 8 77 5. Binding SID in SR-ERO . . . . . . . . . . . . . . . . . . . . 10 78 6. Binding SID in SRv6-ERO . . . . . . . . . . . . . . . . . . . 10 79 7. Implementation Status . . . . . . . . . . . . . . . . . . . . 10 80 7.1. Huawei . . . . . . . . . . . . . . . . . . . . . . . . . 11 81 7.2. Cisco . . . . . . . . . . . . . . . . . . . . . . . . . . 11 82 8. Security Considerations . . . . . . . . . . . . . . . . . . . 11 83 9. Manageability Considerations . . . . . . . . . . . . . . . . 12 84 9.1. Control of Function and Policy . . . . . . . . . . . . . 12 85 9.2. Information and Data Models . . . . . . . . . . . . . . . 12 86 9.3. Liveness Detection and Monitoring . . . . . . . . . . . . 12 87 9.4. Verify Correct Operations . . . . . . . . . . . . . . . . 12 88 9.5. Requirements On Other Protocols . . . . . . . . . . . . . 12 89 9.6. Impact On Network Operations . . . . . . . . . . . . . . 12 90 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 91 10.1. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 13 92 10.1.1. TE-PATH-BINDING TLV . . . . . . . . . . . . . . . . 13 93 10.1.2. Binding SID Flags . . . . . . . . . . . . . . . . . 13 94 10.2. PCEP Error Type and Value . . . . . . . . . . . . . . . 14 95 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 96 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 97 12.1. Normative References . . . . . . . . . . . . . . . . . . 14 98 12.2. Informative References . . . . . . . . . . . . . . . . . 16 99 Appendix A. Contributor Addresses . . . . . . . . . . . . . . . 17 100 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 102 1. Introduction 104 A PCE can compute Traffic Engineering paths (TE paths) through a 105 network that are subject to various constraints. Currently, TE paths 106 are either set up using the RSVP-TE signaling protocol or Segment 107 Routing (SR). We refer to such paths as RSVP-TE paths and SR-TE 108 paths respectively in this document. 110 As per [RFC8402] SR allows a headend node to steer a packet flow 111 along any path. The headend node is said to steer a flow into an 112 Segment Routing Policy (SR Policy). Further, as per 113 [I-D.ietf-spring-segment-routing-policy], an SR Policy is a framework 114 that enables instantiation of an ordered list of segments on a node 115 for implementing a source routing policy with a specific intent for 116 traffic steering from that node. 118 As described in [RFC8402], Binding Segment Identifier (BSID) is bound 119 to an Segment Routed (SR) Policy, instantiation of which may involve 120 a list of SIDs. Any packets received with an active segment equal to 121 BSID are steered onto the bound SR Policy. A BSID may be either a 122 local (SR Local Block (SRLB)) or a global (SR Global Block (SRGB)) 123 SID. As per Section 6.4 of [I-D.ietf-spring-segment-routing-policy] 124 a BSID can also be associated with any type of interfaces or tunnel 125 to enable the use of a non-SR interface or tunnels as segments in a 126 SID-list. 128 [RFC5440] describes the Path Computation Element Protocol (PCEP) for 129 communication between a Path Computation Client (PCC) and a PCE or 130 between a pair of PCEs as per [RFC4655]. [RFC8231] specifies 131 extension to PCEP that allows a PCC to delegate its LSPs to a 132 stateful PCE. A stateful PCE can then update the state of LSPs 133 delegated to it. [RFC8281] specifies a mechanism allowing a PCE to 134 dynamically instantiate an LSP on a PCC by sending the path and 135 characteristics. The PCEP extension to setup and maintain SR-TE 136 paths is specified in [RFC8664]. 138 [RFC8664] provides a mechanism for a network controller (acting as a 139 PCE) to instantiate candidate paths for an SR Policy onto a head-end 140 node (acting as a PCC) using PCEP. For more information on the SR 141 Policy Architecture, see [I-D.ietf-spring-segment-routing-policy]. 143 Binding label/SID has local significance to the ingress node of the 144 corresponding TE path. When a stateful PCE is deployed for setting 145 up TE paths, it may be desirable to report the binding label or SID 146 to the stateful PCE for the purpose of enforcing end-to-end TE/SR 147 policy. A sample Data Center (DC) use-case is illustrated in the 148 following diagram. In the MPLS DC network, an SR LSP (without 149 traffic engineering) is established using a prefix SID advertised by 150 BGP (see [RFC8669]). In IP/MPLS WAN, an SR-TE LSP is setup using the 151 PCE. The list of SIDs of the SR-TE LSP is {A, B, C, D}. The gateway 152 node 1 (which is the PCC) allocates a binding SID X and reports it to 153 the PCE. In order for the access node to steer the traffic over the 154 SR-TE LSP, the PCE passes the SID stack {Y, X} where Y is the prefix 155 SID of the gateway node-1 to the access node. In the absence of the 156 binding SID X, the PCE should pass the SID stack {Y, A, B, C, D} to 157 the access node. This example also illustrates the additional 158 benefit of using the binding SID to reduce the number of SIDs imposed 159 on the access nodes with a limited forwarding capacity. 161 SID stack 162 {Y, X} +-----+ 163 _ _ _ _ _ _ _ _ _ _ _ _ _ _| PCE | 164 | +-----+ 165 | ^ 166 | | Binding 167 | .-----. | SID (X) .-----. 168 | ( ) | ( ) 169 V .--( )--. | .--( )--. 170 +------+ ( ) +-------+ ( ) +-------+ 171 |Access|_( MPLS DC Network )_|Gateway|_( IP/MPLS WAN )_|Gateway| 172 | Node | ( ==============> ) |Node-1 | ( ================> ) |Node-2 | 173 +------+ ( SR path ) +-------+ ( SR-TE path ) +-------+ 174 '--( )--' Prefix '--( )--' 175 ( ) SID of ( ) 176 '-----' Node-1 '-----' 177 is Y SIDs for SR-TE LSP: 178 {A, B, C, D} 180 Figure 1: A sample Use-case of Binding SID 182 A PCC could report the binding label/SID allocated by it to the 183 stateful PCE via Path Computation State Report (PCRpt) message. It 184 is also possible for a stateful PCE to request a PCC to allocate a 185 specific binding label/SID by sending an Path Computation Update 186 Request (PCUpd) message. If the PCC can successfully allocate the 187 specified binding value, it reports the binding value to the PCE. 189 Otherwise, the PCC sends an error message to the PCE indicating the 190 cause of the failure. A local policy or configuration at the PCC 191 SHOULD dictate if the binding label/SID needs to be assigned. 193 In this document, we introduce a new OPTIONAL TLV that a PCC can use 194 in order to report the binding label/SID associated with a TE LSP, or 195 a PCE to request a PCC to allocate a specific binding label/SID 196 value. This TLV is intended for TE LSPs established using RSVP-TE, 197 SR, or any other future method. Also, in the case of SR-TE LSPs, the 198 TLV can carry a binding MPLS label (for SR-TE path with MPLS data- 199 plane) or a binding IPv6 SID (e.g., IPv6 address for SR-TE paths with 200 IPv6 data-plane). Binding value means either MPLS label or SID 201 throughout this document. 203 Additionally, to support the PCE based central controller [RFC8283] 204 operation where the PCE would take responsibility for managing some 205 part of the MPLS label space for each of the routers that it 206 controls, the PCE could directly make the binding label/SID 207 allocation and inform the PCC. See 208 [I-D.ietf-pce-pcep-extension-for-pce-controller] for details. 210 2. Terminology 212 The following terminologies are used in this document: 214 BSID: Binding Segment Identifier. 216 LER: Label Edge Router. 218 LSP: Label Switched Path. 220 LSR: Label Switching Router. 222 PCC: Path Computation Client. 224 PCE: Path Computation Element 226 PCEP: Path Computation Element Protocol. 228 RSVP-TE: Resource ReserVation Protocol-Traffic Engineering. 230 SID: Segment Identifier. 232 SR: Segment Routing. 234 SRGB: Segment Routing Global Block. 236 SRLB: Segment Routing Local Block. 238 TLV: Type, Length, and Value. 240 3. Path Binding TLV 242 The new optional TLV is called "TE-PATH-BINDING TLV" (whose format is 243 shown in the figure below) is defined to carry binding label or SID 244 for a TE path. This TLV is associated with the LSP object specified 245 in ([RFC8231]). The type of this TLV is to be allocated by IANA. 247 0 1 2 3 248 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 1 249 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 250 | Type | Length | 251 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 252 | BT | Flags | Reserved | 253 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 254 ~ Binding Value (variable length) ~ 255 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 257 Figure 2: TE-PATH-BINDING TLV 259 TE-PATH-BINDING TLV is a generic TLV such that it is able to carry 260 MPLS label binding as well as SRv6 Binding SID. It is formatted 261 according to the rules specified in [RFC5440]. 263 Binding Type (BT): A one octet field identifies the type of binding 264 included in the TLV. This document specifies the following BT 265 values: 267 o BT = 0: The binding value is an MPLS label carried in the format 268 specified in [RFC5462] where only the label value is valid, and 269 other fields fields MUST be considered invalid. The Length MUST 270 be set to 7. 272 o BT = 1: Similar to the case where BT is 0 except that all the 273 fields on the MPLS label entry are set on transmission. However, 274 the receiver MAY choose to override TC, S, and TTL values 275 according its local policy. The Length MUST be set to 8. 277 o BT = 2: The binding value is an SRv6 SID with a format of a 16 278 octet IPv6 address, representing the binding SID for SRv6. The 279 Length MUST be set to 20. 281 o BT = 3: The binding value is a 24 octet field, defined in 282 Section 3.1, that contains the SRv6 SID as well as its Behavior 283 and Structure. The Length MUST be set to 28. 285 Flags: 1 octet of flags. Following flags are defined in the new 286 registry "SR Policy Binding SID Flags" as described in 287 Section 10.1.2: 289 0 1 2 3 4 5 6 7 290 +-+-+-+-+-+-+-+-+ 291 | |I|S| 292 +-+-+-+-+-+-+-+-+ 294 where: 296 o S-Flag: This flag encodes the "Specified-BSID-only" behavior. It 297 is used as described in Section 6.2.3 of 298 [I-D.ietf-spring-segment-routing-policy]. 300 o I-Flag: This flag encodes the "Drop Upon Invalid" behavior. It is 301 used as described in Section 8.2 of 302 [I-D.ietf-spring-segment-routing-policy]. 304 Reserved: MUST be set to 0 while sending and ignored on receipt. 306 Binding Value: A variable length field, padded with trailing zeros to 307 a 4-octet boundary. For the BT as 0, the 20 bits represent the MPLS 308 label. For the BT as 1, the 32-bits represent the label stack entry 309 as per [RFC5462]. For the BT as 2, the 128-bits represent the SRv6 310 SID. For the BT as 3, the Binding Value contains SRv6 Endpoint 311 Behavior and SID Structure, defined in Section 3.1. 313 3.1. SRv6 Endpoint Behavior and SID Structure 315 Carried as the Binding Value in the TE-PATH-BINDING TLV when the BT 316 is set to 3. Applicable for SRv6 Binding SIDs 317 [I-D.ietf-spring-srv6-network-programming]. 319 0 1 2 3 320 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 1 321 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 322 | SRv6 Binding SID (16 octets) | 323 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 324 | Reserved | Endpoint Behavior | 325 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 326 | LB Length | LN Length | Fun. Length | Arg. Length | 327 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 329 Figure 4: SRv6 Endpoint Behavior and SID Structure 331 Reserved: 2 octets. MUST be set to 0 on transmit and ignored on 332 receipt. 334 Endpoint Behavior: 2 octets. The Endpoint Behavior code point for 335 this SRv6 SID as defined in section 9.2 of 336 [I-D.ietf-spring-srv6-network-programming]. When set with the value 337 0, the choice of behavior is considered unset. 339 LB Length: 1 octet. SRv6 SID Locator Block length in bits. 341 LN Length: 1 octet. SRv6 SID Locator Node length in bits. 343 Function Length: 1 octet. SRv6 SID Function length in bits. 345 Argument Length: 1 octet. SRv6 SID Arguments length in bits. 347 4. Operation 349 The binding value is allocated by the PCC and reported to a PCE via 350 PCRpt message. If a PCE does not recognize the TE-PATH-BINDING TLV, 351 it would ignore the TLV in accordance with ([RFC5440]). If a PCE 352 recognizes the TLV but does not support the TLV, it MUST send PCErr 353 with Error-Type = 2 (Capability not supported). 355 If a TE-PATH-BINDING TLV is absent in PCRpt message, PCE MUST assume 356 that the corresponding LSP does not have any binding. If a PCE 357 recognizes an invalid binding value (e.g., label value from the 358 reserved label space when MPLS label binding is used), it MUST send 359 the PCErr message with Error-Type = 10 ("Reception of an invalid 360 object") and Error Value = 2 ("Bad label value") as specified in 361 [RFC8664]. 363 Multiple TE-PATH-BINDING TLVs are allowed to be present in the same 364 LSP object. This signifies the presence of multiple binding SIDs for 365 the given LSP. 367 For SRv6 BSIDs, it is RECOMMENDED to always explicitly specify the 368 SRv6 Endpoint Behavior and SID Structure in the TE-PATH-BINDING TLV 369 by setting the BT (Binding Type) to 3, instead of 2. The choice of 370 interpreting SRv6 Endpoint Behavior and SID Structure when none is 371 explicitly specified is left up to the implementation. 373 If a PCE requires a PCC to allocate a specific binding value, it may 374 do so by sending a PCUpd or PCInitiate message containing a TE-PATH- 375 BINDING TLV. If the value can be successfully allocated, the PCC 376 reports the binding value to the PCE. If the PCC considers the 377 binding value specified by the PCE invalid, it MUST send a PCErr 378 message with Error-Type = TBD2 ("Binding label/SID failure") and 379 Error Value = TBD3 ("Invalid SID"). If the binding value is valid, 380 but the PCC is unable to allocate the binding value, it MUST send a 381 PCErr message with Error-Type = TBD2 ("Binding label/SID failure") 382 and Error Value = TBD4 ("Unable to allocate the specified label/ 383 SID"). 385 If a PCC receives TE-PATH-BINDING TLV in any message other than PCUpd 386 or PCInitiate, it MUST close the corresponding PCEP session with the 387 reason "Reception of a malformed PCEP message" (according to 388 [RFC5440]). Similarly, if a PCE receives a TE-PATH-BINDING TLV in 389 any message other than a PCRpt or if the TE-PATH-BINDING TLV is 390 associated with any object other than LSP object, the PCE MUST close 391 the corresponding PCEP session with the reason "Reception of a 392 malformed PCEP message" (according to [RFC5440]). 394 If a PCC wishes to withdraw or modify a previously reported binding 395 value, it MUST send a PCRpt message without any TE-PATH-BINDING TLV 396 or with the TE-PATH-BINDING TLV containing the new binding value 397 respectively. 399 If a PCE wishes to modify a previously requested binding value, it 400 MUST send a PCUpd message with TE-PATH-BINDING TLV containing the new 401 binding value. Absence of TE-PATH-BINDING TLV in PCUpd message means 402 that the PCE does not specify a binding value in which case the 403 binding value allocation is governed by the PCC's local policy. 405 If a PCC receives a valid binding value from a PCE which is different 406 than the current binding value, it MUST try to allocate the new 407 value. If the new binding value is successfully allocated, the PCC 408 MUST report the new value to the PCE. Otherwise, it MUST send a 409 PCErr message with Error-Type = TBD2 ("Binding label/SID failure") 410 and Error Value = TBD4 ("Unable to allocate the specified label/ 411 SID"). 413 In some cases, a stateful PCE can request the PCC to allocate a 414 binding value. It may do so by sending a PCUpd message containing an 415 empty TE-PATH-BINDING TLV, i.e., no binding value is specified 416 (making the length field of the TLV as 4). A PCE can also request 417 PCC to allocate a binding value at the time of initiation by sending 418 a PCInitiate message with an empty TE-PATH-BINDING TLV. If the PCC 419 is unable to allocate a binding value, it MUST send a PCErr message 420 with Error-Type = TBD2 ("Binding label/SID failure") and Error-Value 421 = TBD5 ("Unable to allocate label/SID"). 423 5. Binding SID in SR-ERO 425 In PCEP messages, LSP route information is carried in the Explicit 426 Route Object (ERO), which consists of a sequence of subobjects. 427 [RFC8664] defines a new ERO subobject "SR-ERO subobject" capable of 428 carrying a SID as well as the identity of the node/adjacency (NAI) 429 represented by the SID. The NAI Type (NT) field indicates the type 430 and format of the NAI contained in the SR-ERO. In case of binding 431 SID, the NAI MUST NOT be included and NT MUST be set to zero. So as 432 per Section 5.2.1 of [RFC8664], for NT=0, the F bit is set to 1, the 433 S bit needs to be zero and the Length is 8. Further the M bit is 434 set. If these conditions are not met, the entire ERO MUST be 435 considered invalid and a PCErr message is sent with Error-Type = 10 436 ("Reception of an invalid object") and Error-Value = 11 ("Malformed 437 object"). 439 6. Binding SID in SRv6-ERO 441 [RFC8664] defines a new ERO subobject "SRv6-ERO subobject" for SRv6 442 SID. The NAI MUST NOT be included and NT MUST be set to zero. So as 443 per Section 5.2.1 of [RFC8664], for NT=0, the F bit is set to 1, the 444 S bit needs to be zero and the Length is 24. If these conditions are 445 not met, the entire ERO is considered invalid and a PCErr message is 446 sent with Error-Type = 10 ("Reception of an invalid object") and 447 Error-Value = 11 ("Malformed object") (as per [RFC8664]). 449 7. Implementation Status 451 [Note to the RFC Editor - remove this section before publication, as 452 well as remove the reference to RFC 7942.] 454 This section records the status of known implementations of the 455 protocol defined by this specification at the time of posting of this 456 Internet-Draft, and is based on a proposal described in [RFC7942]. 457 The description of implementations in this section is intended to 458 assist the IETF in its decision processes in progressing drafts to 459 RFCs. Please note that the listing of any individual implementation 460 here does not imply endorsement by the IETF. Furthermore, no effort 461 has been spent to verify the information presented here that was 462 supplied by IETF contributors. This is not intended as, and must not 463 be construed to be, a catalog of available implementations or their 464 features. Readers are advised to note that other implementations may 465 exist. 467 According to [RFC7942], "this will allow reviewers and working groups 468 to assign due consideration to documents that have the benefit of 469 running code, which may serve as evidence of valuable experimentation 470 and feedback that have made the implemented protocols more mature. 472 It is up to the individual working groups to use this information as 473 they see fit". 475 7.1. Huawei 477 o Organization: Huawei 479 o Implementation: Huawei's Router and Controller 481 o Description: An experimental code-point is used and plan to 482 request early code-point allocation from IANA after WG adoption. 484 o Maturity Level: Production 486 o Coverage: Full 488 o Contact: chengli13@huawei.com 490 7.2. Cisco 492 o Organization: Cisco Systems 494 o Implementation: Head-end and controller. 496 o Description: An experimental code-point is currently used. 498 o Maturity Level: Production 500 o Coverage: Full 502 o Contact: mkoldych@cisco.com 504 8. Security Considerations 506 The security considerations described in [RFC5440], [RFC8231], 507 [RFC8281] and [RFC8664] are applicable to this specification. No 508 additional security measure is required. 510 As described [RFC8664], SR allows a network controller to instantiate 511 and control paths in the network. A rouge PCE can manipulate binding 512 SID allocations to move traffic around for some other LSPs that uses 513 BSID in its SR-ERO. 515 Thus, as per [RFC8231], it is RECOMMENDED that these PCEP extensions 516 only be activated on authenticated and encrypted sessions across PCEs 517 and PCCs belonging to the same administrative authority, using 518 Transport Layer Security (TLS) [RFC8253], as per the recommendations 519 and best current practices in BCP195 [RFC7525] (unless explicitly set 520 aside in [RFC8253]). 522 9. Manageability Considerations 524 All manageability requirements and considerations listed in 525 [RFC5440], [RFC8231], and [RFC8664] apply to PCEP protocol extensions 526 defined in this document. In addition, requirements and 527 considerations listed in this section apply. 529 9.1. Control of Function and Policy 531 A PCC implementation SHOULD allow the operator to configure the 532 policy based on which PCC needs to allocates the binding label/SID. 534 9.2. Information and Data Models 536 The PCEP YANG module [I-D.ietf-pce-pcep-yang] could be extended to 537 include policy configuration for binding label/SID allocation. 539 9.3. Liveness Detection and Monitoring 541 Mechanisms defined in this document do not imply any new liveness 542 detection and monitoring requirements in addition to those already 543 listed in [RFC5440]. 545 9.4. Verify Correct Operations 547 Mechanisms defined in this document do not imply any new operation 548 verification requirements in addition to those already listed in 549 [RFC5440], [RFC8231], and [RFC8664]. 551 9.5. Requirements On Other Protocols 553 Mechanisms defined in this document do not imply any new requirements 554 on other protocols. 556 9.6. Impact On Network Operations 558 Mechanisms defined in [RFC5440], [RFC8231], and [RFC8664] also apply 559 to PCEP extensions defined in this document. Further, the mechanism 560 described in this document can help the operator to request control 561 of the LSPs at a particular PCE. 563 10. IANA Considerations 565 10.1. PCEP TLV Type Indicators 567 This document defines a new PCEP TLV; IANA is requested to make the 568 following allocations from the "PCEP TLV Type Indicators" sub- 569 registry of the PCEP Numbers registry, as follows: 571 Value Name Reference 573 TBD1 TE-PATH-BINDING This document 575 10.1.1. TE-PATH-BINDING TLV 577 IANA is requested to create a sub-registry to manage the value of the 578 Binding Type field in the TE-PATH-BINDING TLV. 580 Value Description Reference 582 0 MPLS Label This document 583 1 MPLS Label Stack This document 584 Entry 585 2 SRv6 SID This document 586 3 SRv6 SID with This document 587 Behavior and 588 Structure 590 10.1.2. Binding SID Flags 592 IANA is requested to create a sub-registry to manage the value of the 593 Binding SID Flags field in the TE-PATH-BINDING-TLV. New values are 594 to be assigned by Standards Action [RFC8126]. Each bit should be 595 tracked with the following qualities: 597 o Bit number (count from 0 as the most significant bit) 599 o Flag Name 601 o Reference 603 Bit Description Reference 605 7 Specified-BSID-Only This document 606 Flag (S-Flag) 607 6 Drop Upon Invalid This document 608 Flag (I-Flag) 610 10.2. PCEP Error Type and Value 612 This document defines a new Error-type and Error-Values for the PCErr 613 message. IANA is requested to allocate new error-type and error- 614 values within the "PCEP-ERROR Object Error Types and Values" 615 subregistry of the PCEP Numbers registry, as follows: 617 Error-Type Meaning 618 ---------- ------- 619 TBD2 Binding label/SID failure: 621 Error-value = TBD3: Invalid SID 622 Error-value = TBD4: Unable to allocate 623 the specified 624 label/SID 625 Error-value = TBD5: Unable to allocate 626 label/SID 628 11. Acknowledgements 630 We like to thank Milos Fabian and Mrinmoy Das for thier valuable 631 comments. 633 12. References 635 12.1. Normative References 637 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 638 Requirement Levels", BCP 14, RFC 2119, 639 DOI 10.17487/RFC2119, March 1997, 640 . 642 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 643 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 644 DOI 10.17487/RFC5440, March 2009, 645 . 647 [RFC5462] Andersson, L. and R. Asati, "Multiprotocol Label Switching 648 (MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic 649 Class" Field", RFC 5462, DOI 10.17487/RFC5462, February 650 2009, . 652 [RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, 653 "Recommendations for Secure Use of Transport Layer 654 Security (TLS) and Datagram Transport Layer Security 655 (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May 656 2015, . 658 [RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running 659 Code: The Implementation Status Section", BCP 205, 660 RFC 7942, DOI 10.17487/RFC7942, July 2016, 661 . 663 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 664 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 665 May 2017, . 667 [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path 668 Computation Element Communication Protocol (PCEP) 669 Extensions for Stateful PCE", RFC 8231, 670 DOI 10.17487/RFC8231, September 2017, 671 . 673 [RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody, 674 "PCEPS: Usage of TLS to Provide a Secure Transport for the 675 Path Computation Element Communication Protocol (PCEP)", 676 RFC 8253, DOI 10.17487/RFC8253, October 2017, 677 . 679 [RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path 680 Computation Element Communication Protocol (PCEP) 681 Extensions for PCE-Initiated LSP Setup in a Stateful PCE 682 Model", RFC 8281, DOI 10.17487/RFC8281, December 2017, 683 . 685 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 686 Decraene, B., Litkowski, S., and R. Shakir, "Segment 687 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 688 July 2018, . 690 [RFC8664] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W., 691 and J. Hardwick, "Path Computation Element Communication 692 Protocol (PCEP) Extensions for Segment Routing", RFC 8664, 693 DOI 10.17487/RFC8664, December 2019, 694 . 696 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 697 Writing an IANA Considerations Section in RFCs", BCP 26, 698 RFC 8126, DOI 10.17487/RFC8126, June 2017, 699 . 701 [I-D.ietf-spring-srv6-network-programming] 702 Filsfils, C., Camarillo, P., Leddy, J., Voyer, D., 703 Matsushima, S., and Z. Li, "SRv6 Network Programming", 704 draft-ietf-spring-srv6-network-programming-24 (work in 705 progress), October 2020. 707 12.2. Informative References 709 [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation 710 Element (PCE)-Based Architecture", RFC 4655, 711 DOI 10.17487/RFC4655, August 2006, 712 . 714 [RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An 715 Architecture for Use of PCE and the PCE Communication 716 Protocol (PCEP) in a Network with Central Control", 717 RFC 8283, DOI 10.17487/RFC8283, December 2017, 718 . 720 [RFC8669] Previdi, S., Filsfils, C., Lindem, A., Ed., Sreekantiah, 721 A., and H. Gredler, "Segment Routing Prefix Segment 722 Identifier Extensions for BGP", RFC 8669, 723 DOI 10.17487/RFC8669, December 2019, 724 . 726 [I-D.ietf-spring-segment-routing-policy] 727 Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and 728 P. Mattes, "Segment Routing Policy Architecture", draft- 729 ietf-spring-segment-routing-policy-08 (work in progress), 730 July 2020. 732 [I-D.ietf-pce-pcep-extension-for-pce-controller] 733 Li, Z., Peng, S., Negi, M., Zhao, Q., and C. Zhou, "PCEP 734 Procedures and Protocol Extensions for Using PCE as a 735 Central Controller (PCECC) of LSPs", draft-ietf-pce-pcep- 736 extension-for-pce-controller-07 (work in progress), 737 September 2020. 739 [I-D.ietf-pce-pcep-yang] 740 Dhody, D., Hardwick, J., Beeram, V., and J. Tantsura, "A 741 YANG Data Model for Path Computation Element 742 Communications Protocol (PCEP)", draft-ietf-pce-pcep- 743 yang-14 (work in progress), July 2020. 745 Appendix A. Contributor Addresses 747 Dhruv Dhody 748 Huawei Technologies 749 Divyashree Techno Park, Whitefield 750 Bangalore, Karnataka 560066 751 India 753 EMail: dhruv.ietf@gmail.com 755 Mahendra Singh Negi 756 RtBrick India 757 N-17L, Floor-1, 18th Cross Rd, HSR Layout Sector-3 758 Bangalore, Karnataka 560102 759 India 761 EMail: mahend.ietf@gmail.com 763 Mike Koldychev 764 Cisco Systems, Inc. 765 2000 Innovation Drive 766 Kanata, Ontario K2K 3E8 767 Canada 769 Email: mkoldych@cisco.com 771 Zafar Ali 772 Cisco Systems, Inc. 774 Email: zali@cisco.com 776 Authors' Addresses 778 Siva Sivabalan 779 Ciena Corporation 781 EMail: msiva282@gmail.com 783 Clarence Filsfils 784 Cisco Systems, Inc. 785 Pegasus Parc 786 De kleetlaan 6a, DIEGEM BRABANT 1831 787 BELGIUM 789 EMail: cfilsfil@cisco.com 790 Jeff Tantsura 791 Apstra, Inc. 793 EMail: jefftant.ietf@gmail.com 795 Jonathan Hardwick 796 Metaswitch Networks 797 100 Church Street 798 Enfield, Middlesex 799 UK 801 EMail: Jonathan.Hardwick@metaswitch.com 803 Stefano Previdi 804 Huawei Technologies 806 EMail: stefano@previdi.net 808 Cheng Li 809 Huawei Technologies 810 Huawei Campus, No. 156 Beiqing Rd. 811 Beijing 100095 812 China 814 EMail: chengli13@huawei.com