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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) No issues found here. Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 PCE Working Group Y. Lee 2 Internet Draft SKKU 3 Intended status: Standard Track 4 Expires: March 10, 2020 H. Zheng (Editor) 5 Huawei 6 R. Casellas 7 R. Vilalta 8 CTTC 10 D. Ceccarelli 11 F. Lazzeri 12 Ericsson 14 September 10, 2019 16 PCEP Extension for Flexible Grid Networks 18 draft-ietf-pce-flexible-grid-02 20 Abstract 22 This document provides the Path Computation Element Communication 23 Protocol (PCEP) extensions for the support of Routing and Spectrum 24 Assignment (RSA) in Flexible Grid networks. 26 Status of this Memo 28 This Internet-Draft is submitted to IETF in full conformance with 29 the provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF), its areas, and its working groups. Note that 33 other groups may also distribute working documents as Internet- 34 Drafts. 36 Internet-Drafts are draft documents valid for a maximum of six 37 months and may be updated, replaced, or obsoleted by other documents 38 at any time. It is inappropriate to use Internet-Drafts as 39 reference material or to cite them other than as "work in progress." 41 The list of current Internet-Drafts can be accessed at 42 http://www.ietf.org/ietf/1id-abstracts.txt 44 The list of Internet-Draft Shadow Directories can be accessed at 45 http://www.ietf.org/shadow.html. 47 This Internet-Draft will expire on June 19, 2019. 49 Copyright Notice 51 Copyright (c) 2019 IETF Trust and the persons identified as the 52 document authors. All rights reserved. 54 This document is subject to BCP 78 and the IETF Trust's Legal 55 Provisions Relating to IETF Documents 56 (http://trustee.ietf.org/license-info) in effect on the date of 57 publication of this document. Please review these documents 58 carefully, as they describe your rights and restrictions with 59 respect to this document. Code Components extracted from this 60 document must include Simplified BSD License text as described in 61 Section 4.e of the Trust Legal Provisions and are provided without 62 warranty as described in the Simplified BSD License. 64 Table of Contents 66 1. Terminology ................................................. 3 67 2. Requirements Language ....................................... 3 68 3. Introduction ................................................ 3 69 4. Spectrum Assignment (SA) Object ............................. 4 70 4.1. Frequency-Slot Selection TLV ........................... 6 71 4.2. Frequency-slot Restriction Constraint TLV .............. 8 72 4.2.1. Frequency-Slot Restriction Field ................. 10 73 5. Encoding of a RSA Path Reply ............................... 10 74 5.1. Error Indicator........................................ 11 75 5.2. NO-PATH Indicator ..................................... 12 76 6. Manageability Considerations ............................... 12 77 6.1. Control of Function and Policy ........................ 12 78 6.2. Information and Data Models ........................... 13 79 6.3. Verifying Correct Operation ........................... 13 80 6.4. Requirements on Other Protocols and Functional Components13 81 6.5. Impact on Network Operation ........................... 13 82 7. Security Considerations .................................... 13 83 8. IANA Considerations ........................................ 14 84 8.1. New PCEP Object........................................ 14 85 8.2. New PCEP TLV: Frequency Slot Selection TLV ............. 14 86 8.3. New PCEP TLV: Frequency Slot Restriction Constraint TLV. 14 87 8.4. New PCEP TLV: Spectrum Allocation TLV .................. 15 88 8.5. New No-Path Reasons ................................... 15 89 8.6. New Error-Types and Error-Values ....................... 16 90 9. References ................................................. 16 91 9.1. Normative References .................................. 16 92 9.2. Informative References ................................ 17 93 10. Contributors .............................................. 18 94 Authors' Addresses ............................................ 19 96 1. Terminology 98 This document uses the terminology defined in [RFC4655], [RFC5440] 99 and [RFC7698]. 101 2. Requirements Language 103 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 104 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 105 "OPTIONAL" in this document are to be interpreted as described in 106 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all 107 capitals, as shown here. 109 3. Introduction 111 [RFC4655] defines a Path Computation Element (PCE) based path 112 computation architecture and explains how a Path Computation Element 113 (PCE) may compute Label Switched Paths (LSP) in Multiprotocol Label 114 Switching Traffic Engineering (MPLS-TE) and Generalized MPLS (GMPLS) 115 networks at the request of Path Computation Clients (PCCs). A PCC 116 is said to be any network component that makes such a request and 117 may be, for instance, an Optical Switching Element within a 118 Wavelength Division Multiplexing (WDM) network. The PCE, itself, 119 can be located anywhere within the network, and may be within an 120 optical switching element, a Network Management System (NMS) or 121 Operational Support System (OSS), or may be an independent network 122 server. 124 The PCE communications Protocol (PCEP) is the communication protocol 125 used between a PCC and a PCE, and may also be used between 126 cooperating PCEs. [RFC4657] sets out the common protocol 127 requirements for PCEP. Additional application-specific requirements 128 for PCEP are deferred to separate documents. 130 [PCEP-WSON] provides the PCEP extensions for the support of Routing 131 and Wavelength Assignment (RWA) in Wavelength Switched Optical 132 Networks (WSON) based on the requirements specified in [RFC6163] and 133 [RFC7449]. 135 To allow efficient allocation of optical spectral bandwidth for 136 systems that have high bit-rates, the International 137 Telecommunication Union Telecommunication Standardization Sector 138 (ITU-T) has extended its Recommendations [G.694.1] and [G.872] to 139 include a new Dense Wavelength Division Multiplexing (DWDM) grid by 140 defining a set of nominal central frequencies, channel spacings, and 141 the concept of the "frequency slot". In such an environment, a data- 142 plane connection is switched based on allocated, variable-sized 143 frequency ranges within the optical spectrum, creating what is known 144 as a flexible grid (flexi-grid). [RFC7698] provides Framework and 145 Requirements for GMPLS-Based Control of Flexi-Grid Dense Wavelength 146 Division Multiplexing (DWDM) Networks. 148 The terms "Routing and Spectrum Assignment" (RSA) is introduced in 149 [RFC7698] to refer to the process determines a route and frequency 150 slot for an LSP. Hence, when a route is computed, the spectrum 151 assignment process determines the central frequency and slot width. 152 The term "Spectrum Switched Optical Networks" is also introduced in 153 [RFC7698] to refer to a flexi-grid enabled DWDM network that is 154 controlled by a GMPLS or PCE control plane. 156 This document provides PCEP extensions to support RSA in SSONs. 158 Figure 2 shows one typical PCE based implementation, which is 159 referred to as the Combined Routing and Spectrum Assignment (R&SA) 160 [RFC7698]. With this architecture, the two processes of routing and 161 spectrum assignment are accessed via a single PCE. This architecture 162 is the base architecture from which the PCEP extensions are 163 specified in this document. 165 +----------------------------+ 166 +-----+ | +-------+ +--+ | 167 | | | |Routing| |SA| | 168 | PCC |<----->| +-------+ +--+ | 169 | | | | 170 +-----+ | PCE | 171 +----------------------------+ 173 Figure 1 Combined Process (R&SA) architecture 175 4. Spectrum Assignment (SA) Object 177 This document aligns with GMPLS extensions for PCEP [PCEP-GMPLS] for 178 generic property such as label, label-set and label assignment 179 noting that frequency is a type of label. Frequency restrictions and 180 constraints are also formulated in terms of labels per [RFC7579]. 182 Spectrum allocation can be performed by the PCE by different means: 184 (a) By means of Explicit Label Control (ELC) where the PCE 185 allocates which label to use for each interface/node along the 186 path. 188 (b) By means of a Label Set where the PCE provides a range of 189 potential frequency slots to allocate by each node along the path. 191 Option (b) allows distributed spectrum allocation (performed during 192 signaling) to complete spectrum assignment. 194 Additionally, given a range of potential spectrums to allocate, a PC 195 Request SHOULD convey the heuristic / mechanism to the allocation. 197 The format Routing Backus-Naur Form (RBNF) [RFC5511] of a PCReq 198 message per [RFC5440] after incorporating the Spectrum Assignment 199 (SA) object is as follows: 201 ::= 203 [] 205 207 Where: 209 ::=[] 211 ::= 213 215 [ ] 217 [other optional objects...] 219 If the SA object is present in the request, it MUST be encoded after 220 the GENERALIZED ENDPOINTS object. 222 SA Object-Class is (TBD1) (To be assigned by IANA). 224 SA Object-Type is 1. 226 The format of the Spectrum Assignment (SA) object body is as 227 follows: 229 0 1 2 3 230 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 1 231 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 232 | Reserved | Flags |M| 233 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 234 | Frequency-Slot Selection TLV | 235 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 236 | Frequency-Slot Restriction Constraint TLV | 237 . . 238 . . 239 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 240 // Optional TLVs // 241 | | 242 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 244 Figure 2 SA Object 246 o Reserved (16 bits) 248 o Flags (16 bits) 250 One Flag bit is allocated as follows: 252 M (Mode - 1 bit): M bit is used to indicate the mode of 253 spectrum assignment. When M bit is set to 1, this indicates 254 that the spectrum assigned by the PCE must be explicit. That 255 is, the selected way to convey the allocated spectrum is by 256 means of Explicit Label Control (ELC) [RFC4003] for each hop of 257 a computed LSP. Otherwise, the spectrum assigned by the PCE 258 needs not be explicit (i.e., it can be suggested in the form of 259 label set objects in the corresponding response, to allow 260 distributed SA. In such case, the PCE MUST return a Label Set 261 Field as described in Section 2.6 of [RFC7579] in the response. 262 See Section 5 of this document for the encoding discussion of a 263 Label Set Field in a PCRep message. 265 4.1. Frequency-Slot Selection TLV 267 The Frequency-Slot Selection TLV is used to indicate the frequency- 268 slot selection constraint in regard to the order of frequency-slot 269 assignment to be returned by the PCE. This TLV is only applied when 270 M bit is set in the SA Object specified in Section 4. This TLV 271 SHOULD NOT be present and MUST be ignored when the M bit is cleared. 273 The Frequency-Slot Selection sub-TLV value field is defined as: 275 0 1 2 3 276 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 1 277 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 278 |S| FSA Method | Reserved | 279 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 281 Where: 283 Frequency-Slot Assignment (FSA) Method (7 bits): 285 0: unspecified (any); This does not constrain the SA method 286 used by a PCC This value is implied when the 287 Frequency-Slot Selection sub-TLV is absent. 289 1: First-Fit. All the feasible frequency slots are numbered 290 (based on "n" parameter), and this SA method chooses the 291 available frequency-slot with the lowest index, where "n" is 292 the parameter in f = 193.1 THz + n x 0.00625 THz where 193.1 293 THz is the ITU-T "anchor frequency" and "n" is a positive 294 integer including 0 [RFC7698]. 296 2: Random. This SA method chooses a feasible frequency-slot 297 value of "n" randomly. 299 3-127: Unassigned. 301 S (Symmetry, 1 bit): This flag is only meaningful when the request 302 is for a bidirectional LSP (see [RFC5440]). 304 0 denotes requiring the same frequency-slot in both directions; 305 1 denotes that different spectrums on both directions are 306 allowed. 308 IANA is to allocate a new PCEP TLV type, Frequency-Slot Selection 309 TLV (TBD2) in the "PCEP TLV Type Indicators" subregistry 310 (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type- 311 indicators). 313 The processing rules for this TLV are as follows: 315 If a PCE does not support the attribute(s), its 316 behavior is specified below: 318 - S bit clear not supported: a PathErr MUST be generated with 319 The Error Code "Routing Problem" (24) with error sub-code 320 "Unsupported Frequency slot Selection Symmetry value" (TBD3). 322 - FSA method not supported: a PathErr MUST be generated with the 323 Error Code "Routing Problem" (24) with error sub-code 324 "Unsupported Frequency Slot Assignment value" (TBD4). 326 4.2. Frequency-slot Restriction Constraint TLV 328 For any request that contains a Frequency-slot assignment, the 329 requester (PCC) must be able to specify a restriction on the 330 frequency-slots to be used. This restriction is to be interpreted by 331 the PCE as a constraint on the tuning ability of the origination 332 laser transmitter or on any other maintenance related constraints. 334 The format of the Frequency-Slot Restriction Constraint TLV is as 335 follows: 337 ::= 339 ( 341 )... 343 Where 345 ::= [] 347 See Section 4.3.1 in [PCEP-WSON] for the encoding of the Link 348 Identifiers Field. 349 IANA is to allocate a new PCEP TLV, the Frequency slot Restriction 350 Constraint TLV type (TBD5). This TLV MAY appear more than once to be 351 able to specify multiple restrictions. 353 The TLV data is defined as follows: 355 0 1 2 3 356 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 1 357 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 358 | Action | Count | Reserved | 359 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 360 | Link Identifiers | 361 | . . . | 362 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 363 | Frequency Slot Restriction Field | 364 // . . . . // 365 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 367 Figure 3 spectrum Restriction Constraint TLV Encoding 369 o Action: 8 bits 371 0 - Inclusive List indicates that one or more link identifiers 372 are included in the Link Set. Each identifies a separate link 373 that is part of the set. 375 1 - Inclusive Range indicates that the Link Set defines a 376 range of links. It contains two link identifiers. The first 377 identifier indicates the start of the range (inclusive). The 378 second identifier indicates the end of the range (inclusive). 379 All links with numeric values between the bounds are 380 considered to be part of the set. A value of zero in either 381 position indicates that there is no bound on the corresponding 382 portion of the range. Note that the Action field can be set to 383 0 when unnumbered link identifier is used. 385 o Count: The number of the link identifiers (8 bits) 387 Note that a PCC MAY add a frequency slot restriction that applies to 388 all links by setting the Count field to zero and specifying just a 389 set of frequency slots. 391 Note that all link identifiers in the same list must be of the same 392 type. 394 o Reserved: Reserved for future use (16 bits) 396 o Link Identifiers: Identifies each link ID for which restriction 397 is applied. The length is dependent on the link format and the Count 398 field. See Section 4.3.1 in [PCEP-WSON] for Link Identifier 399 encoding. 401 4.2.1. Frequency-Slot Restriction Field 403 The Frequency-Slot Restriction Field of the Frequency slot 404 restriction TLV is encoded as defined in section 4.2 of [RFC8363]. 406 5. Encoding of a RSA Path Reply 408 This section provides the encoding of a RSA Path Reply for frequency 409 slot allocation as discussed in Section 4. Spectrum Allocation TLV 411 IANA is to allocate a new PCEP TLV type, the Spectrum Allocation TLV 412 type (TBD6). The TLV data is defined as follows: 414 0 1 2 3 415 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 1 416 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 417 | Type | Length |M| 418 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 419 | Link Identifier | 420 | . . . | 421 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 422 | Allocated Spectrum(s) | 423 // . . . . // 424 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 426 Figure 4 Spectrum Allocation TLV Encoding 428 o Type (16 bits): The type of the TLV. 430 o Length (15 bits): The length of the TLV including the Type and 431 Length fields. 433 o M (Mode): 1 bit 435 - 0 indicates the allocation is under Explicit Label Control. 437 - 1 indicates the allocation is expressed in Label Sets. 439 Note that all link identifiers in the same list must be of the same 440 type. 442 o Link Identifier (variable): Identifies the interface to which 443 assignment spectrum(s) is applied. See Section 3.3 for Link 444 Identifier encoding. 446 o Allocated Spectrum(s) (variable): Indicates the allocated 447 spectrum(s) to the link identifier. See Section 3.3.1 for encoding 448 details. 450 This TLV is encoded as an attributes TLV, per [RFC5420], which is 451 carried in the ERO LSP Attribute Subobjects per [RFC7570]. 453 5.1. Error Indicator 455 To indicate errors associated with the RSA request, a new Error Type 456 (TDB) and subsequent error-values are defined as follows for 457 inclusion in the PCEP-ERROR Object: 459 A new Error-Type (TBD7) and subsequent error-values are defined as 460 follows: 462 Error-Type=TBD7; Error-value=1: if a PCE receives a RSA 463 request and the PCE is not capable of processing the request 464 due to insufficient memory, the PCE MUST send a PCErr message 465 with a PCEP-ERROR Object (Error-Type=TDB) and an Error- 466 value(Error-value=1). The PCE stops processing the request. 467 The corresponding RSA request MUST be cancelled at the PCC. 469 Error-Type=TBD7; Error-value=2: if a PCE receives a RSA 470 request and the PCE is not capable of RSA computation, the PCE 471 MUST send a PCErr message with a PCEP-ERROR Object (Error- 472 Type=TDB) and an Error-value (Error-value=2). The PCE stops 473 processing the request. The corresponding RSA computation 474 MUST be cancelled at the PCC. 476 5.2. NO-PATH Indicator 478 To communicate the reason(s) for not being able to find RSA for the 479 path request, the NO-PATH object can be used in the corresponding 480 response. The format of the NO-PATH object body is defined in 481 [RFC5440]. The object may contain a NO-PATH-VECTOR TLV to provide 482 additional information about why a path computation has failed. 484 One new bit flag is defined to be carried in the Flags field in the 485 NO-PATH-VECTOR TLV carried in the NO-PATH Object. 487 Bit TBD8: When set, the PCE indicates no feasible route was 488 found that meets all the constraints (e.g., spectrum 489 restriction, etc.) associated with RSA. 491 6. Manageability Considerations 493 Manageability of SSON Routing and Spectrum Assignment (RSA) with PCE 494 must address the following considerations: 496 6.1. Control of Function and Policy 498 In addition to the parameters already listed in Section 8.1 of 499 [RFC5440], a PCEP implementation SHOULD allow configuring the 500 following PCEP session parameters on a PCC: 502 The ability to send a Flexi-Grid RSA request. 504 In addition to the parameters already listed in Section 8.1 of 505 [RFC5440], a PCEP implementation SHOULD allow configuring the 506 following PCEP session parameters on a PCE: 508 The support for Flexi-Grid RSA . 510 A set of Flexi-Grid RSA specific policies (authorized sender, 511 request rate limiter, etc). 513 These parameters may be configured as default parameters for any 514 PCEP session the PCEP speaker participates in, or may apply to a 515 specific session with a given PCEP peer or a specific group of 516 sessions with a specific group of PCEP peers. 518 6.2. Information and Data Models 520 Extensions to the PCEP YANG module may include to cover the Flexi- 521 Grid RSA information introduced in this document. Liveness Detection 522 and Monitoring 524 Mechanisms defined in this document do not imply any new liveness 525 detection and monitoring requirements in addition to those already 526 listed in section 8.3 of [RFC5440]. 528 6.3. Verifying Correct Operation 530 Mechanisms defined in this document do not imply any new 531 verification requirements in addition to those already listed in 532 section 8.4 of [RFC5440] 534 6.4. Requirements on Other Protocols and Functional Components 536 The PCE Discovery mechanisms ([RFC5089] and [RFC5088]) may be used 537 to advertise Flexi-Grid RSA path computation capabilities to PCCs. 538 This draft has requirements on other protocols (ERO objects, etc. 539 which are under TEAS or CCAMP.) 541 6.5. Impact on Network Operation 543 Mechanisms defined in this document do not imply any new network 544 operation requirements in addition to those already listed in 545 section 8.6 of [RFC5440]. 547 7. Security Considerations 549 This document has no requirement for a change to the security models 550 within PCEP. However, the additional information distributed in 551 order to address the RSA problem represents a disclosure of network 552 capabilities that an operator may wish to keep private. 553 Consideration should be given to securing this information. 555 8. IANA Considerations 557 IANA is requested to make allocations from the sub-registries as 558 described in the following sections. 560 8.1. New PCEP Object 562 As described in Section 4.1, a new PCEP Object is defined to carry 563 frequency-slot assignment related constraints. IANA is to allocate 564 the following from "PCEP Objects" sub-registry 565 (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-objects): 567 Object Class Name Object Reference 568 Value Type 569 --------------------------------------------------------- 571 TBD1 SA 1: Spectrum Assignment [This.I-D] 573 8.2. New PCEP TLV: Frequency Slot Selection TLV 575 As described in Sections 4.2, a new PCEP TLV is defined to indicate 576 spectrum selection constraints. IANA is to allocate this new TLV 577 from the "PCEP TLV Type Indicators" subregistry 578 (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type- 579 indicators). 581 Value Description Reference 582 --------------------------------------------------------- 583 TBD2 Spectrum Selection [This.I-D] 585 8.3. New PCEP TLV: Frequency Slot Restriction Constraint TLV 587 As described in Section 4.3, a new PCEP TLV is defined to indicate 588 wavelength restriction constraints. IANA is to allocate this new TLV 589 from the "PCEP TLV Type Indicators" subregistry 590 (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type- 591 indicators). 593 Value Description Reference 594 --------------------------------------------------------- 595 TBD5 Frequency Slot Restriction [This.I-D] 596 Constraint 598 8.4. New PCEP TLV: Spectrum Allocation TLV 600 As described in Section 5, a new PCEP TLV is defined to indicate the 601 allocation of freq-slots(s) by the PCE in response to a request by 602 the PCC. IANA is to allocate this new TLV from the "PCEP TLV Type 603 Indicators" subregistry 604 (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type- 605 indicators). 607 Value Description Reference 608 --------------------------------------------------------- 609 TBD6 Spectrum Allocation [This.I-D] 611 8.5. New No-Path Reasons 613 As described in Section 4.3, a new bit flag are defined to be 614 carried in the Flags field in the NO-PATH-VECTOR TLV carried in the 615 NO-PATH Object. This flag, when set, indicates that no feasible 616 route was found that meets all the RSA constraints (e.g., spectrum 617 restriction, signal compatibility, etc.) associated with a RSA path 618 computation request. 620 IANA is to allocate this new bit flag from the "PCEP NO-PATH-VECTOR 621 TLV Flag Field" subregistry 622 (http://www.iana.org/assignments/pcep/pcep.xhtml#no-path-vector- 623 tlv). 625 Bit Description Reference 626 ----------------------------------------------------- 627 TBD8 No RSA constraints met [This.I-D] 629 8.6. New Error-Types and Error-Values 631 As described in Section 5.1, new PCEP error codes are defined for 632 WSON RWA errors. IANA is to allocate from the ""PCEP-ERROR Object 633 Error Types and Values" sub-registry 634 (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-error-object). 636 Error- Meaning Error-Value Reference 637 Type 638 --------------------------------------------------------------- 640 TBD7 Flexi-Grid RSA Error 1: Insufficient [This.I-D] 641 Memory 643 2: RSA computation [This.I-D] 644 Not supported 646 8.7. New Error-Values for Existing Error Type (24) 648 As discussed in Section 4.1, two new PathErr values for the Existing 649 Error Type (24) are to be allocated: 651 Meaning Error-Value Reference 653 --------------------------------------------------------------- 654 Unsupported Frequency slot 655 Selection Symmetry value TBD3 [This.I-D] 657 Unsupported Frequency Slot 658 Assignment value TBD4 [This.I-D] 660 9. References 662 9.1. Normative References 664 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 665 Requirement Levels", BCP 14, RFC 2119, March 1997. 667 [RFC4003] Berger, L., "GMPLS Signaling Procedure for Egress 668 Control", RFC 4003, February 2005. 670 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 671 Element (PCE) communication Protocol", RFC 5440, March 672 2009. 674 [RFC5511] A. Farrel, "Routing Backus-Naur Form (RBNF): A Syntax Used 675 to Form Encoding Rules in Various Routing Protocol 676 Specifications", RFC 5511, April 2009. 678 [RFC5088] Le Roux, JL, JP. Vasseur, Y. Ikejiri, and R. Zhang, "OSPF 679 Protocol Extensions for Path Computation Element (PCE) 680 Discovery," RFC 5088, January 2008. 682 [RFC5089] Le Roux, JL, JP. Vasseur, Y. Ikejiri, and R. Zhang, "IS-IS 683 Protocol Extensions for Path Computation Element (PCE) 684 Discovery," RFC 5089, January 2008. 686 [RFC8174] B. Leiba, "Ambiguity of Uppercase vs Lowercase in RFC 2119 687 Key Words", RFC 8174, May 2017. 689 9.2. Informative References 691 [PCEP-GMPLS] Margaria, et al., "PCEP extensions for GMPLS", draft- 692 ietf-pce-gmpls-pcep-extensions, work in progress. 694 [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation 695 Element (PCE)-Based Architecture", RFC 4655, August 2006. 697 [RFC4657] Ash, J. and J. Le Roux, "Path Computation Element (PCE) 698 Communication Protocol Generic Requirements", RFC 4657, 699 September 2006. 701 [RFC5420] Farrel, A. "Encoding of Attributes for MPLS LSP 702 Establishment Using Resource Reservation Protocol Traffic 703 Engineering (RSVP-TE)", RFC 5420, February 2009. 705 [RFC6163] Lee, Y. and Bernstein, G. (Editors), and W. Imajuku, 706 "Framework for GMPLS and PCE Control of Wavelength 707 Switched Optical Networks", RFC 6163, March 2011. 709 [RFC7449] Lee, Y., et. al., "PCEP Requirements for WSON Routing and 710 Wavelength Assignment", RFC 7449, February 2015. 712 [RFC7570] Margaria, et al., "Label Switched Path (LSP) Attribute in 713 the Explicit Route Object (ERO)", RFC 7570, July 2015. 715 [RFC7579] Bernstein and Lee, "General Network Element Constraint 716 Encoding for GMPLS Controlled Networks", RFC 7579, June 717 2015. 719 [PCEP-WSON] Y. Lee (Ed.), and R. Casellas (Ed.), "PCEP Extension for 720 WSON Routing and Wavelength Assignment", draft-ietf-pce- 721 wson-rwa-ext, work in progress. 723 [RFC7698] O. Gonzalez de Dios, R. Casellas, editors, "Framework and 724 Requirements for GMPLS-Based Control of Flexi-Grid Dense 725 Wavelength Division Multiplexing (DWDM) Networks", RFC 726 7698, November 2015. 728 [RFC8363] X. Zhang, H. Zheng, R. Casellas, O. Gonzalez de Dios, D. 729 Ceccarelli, "GMPLS OSPF-TE Extensions in Support of Flexi- 730 Grid Dense Wavelength Division Multiplexing (DWDM) 731 Networks", RFC8363, May 2018. 733 [G.694.1] "Spectral grids for WDM applications: DWDM frequency 734 grid", ITU-T G.694.1, February 2012. 736 [G.872] "Architecture of optical transport networks", ITU-T G.872, 737 January 2017. 739 10. Contributors 740 Authors' Addresses 742 Young Lee 743 Sung Kyun Kwan University 744 Email: younglee.tx@gmail.com 746 Haomian Zheng (Editor) 747 Huawei Technologies 748 Email: zhenghaomian@huawei.com 750 Ramon Casellas 751 CTTC 752 Av. Carl Friedrich Gauss n7 753 Castelldefels, Barcelona 08860 754 Spain 756 Email: ramon.casellas@cttc.es 758 Ricard Vilalta 759 CTTC 760 Email: ricard.vilalta@cttc.es 762 Daniele Ceccarelli 763 Ericsson AB 764 Gronlandsgatan 21 765 Kista - Stockholm 766 Email: daniele.ceccarelli@ericsson.com 768 Francesco Lazzeri 769 Ericsson 770 Via Melen 77 771 Genova - Italy 772 Email: francesco.lazzeri@ericsson.com