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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) -- Possible downref: Non-RFC (?) normative reference: ref. 'G.694.1' -- Obsolete informational reference (is this intentional?): RFC 6982 (Obsoleted by RFC 7942) Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group A. Farrel 3 Internet Draft D. King 4 Updates: 3471, 6205 (if approved) Old Dog Consulting 5 Intended Status: Standards Track Y. Li 6 Expires: 6 August 2014 Nanjing University 7 F. Zhang 8 Huawei Technologies 10 6 February 2014 12 Generalized Labels for the Flexi-Grid in 13 Lambda Switch Capable (LSC) Label Switching Routers 15 draft-farrkingel-ccamp-flexigrid-lambda-label-08.txt 17 Abstract 19 GMPLS supports the description of optical switching by identifying 20 entries in fixed lists of switchable wavelengths (called grids) 21 through the encoding of lambda labels. Work within the ITU-T Study 22 Group 15 has defined a finer granularity grid, and the facility to 23 flexibly select different widths of spectrum from the grid. This 24 document defines a new GMPLS lambda label format to support this 25 flexi-grid. 27 This document updates RFC 3471 and RFC 6205 by introducing a new 28 label format. 30 Status of this Memo 32 This Internet-Draft is submitted to IETF in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF), its areas, and its working groups. Note that other 37 groups may also distribute working documents as Internet-Drafts. 39 Internet-Drafts are draft documents valid for a maximum of six months 40 and may be updated, replaced, or obsoleted by other documents at any 41 time. It is inappropriate to use Internet-Drafts as reference 42 material or to cite them other than as "work in progress." 44 The list of current Internet-Drafts can be accessed at 45 http://www.ietf.org/ietf/1id-abstracts.txt 47 The list of Internet-Draft Shadow Directories can be accessed at 48 http://www.ietf.org/shadow.html 50 Copyright Notice 52 Copyright (c) 2014 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents 57 (http://trustee.ietf.org/license-info) in effect on the date of 58 publication of this document. Please review these documents 59 carefully, as they describe your rights and restrictions with respect 60 to this document. Code Components extracted from this document must 61 include Simplified BSD License text as described in Section 4.e of 62 the Trust Legal Provisions and are provided without warranty as 63 described in the Simplified BSD License. 65 Table of Contents 67 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 68 1.1. Conventions Used in This Document . . . . . . . . . . . . . 3 69 2. Overview of Flexi-Grid . . . . . . . . . . . . . . . . . . . . 3 70 3. Fixed Grid Lambda Label Encoding . . . . . . . . . . . . . . . 4 71 4. Flexi-Grid Label Format and Values . . . . . . . . . . . . . . 5 72 4.1 Flexi-Grid Label Encoding . . . . . . . . . . . . . . . . . . 5 73 4.2. Considerations of Bandwidth . . . . . . . . . . . . . . . . 6 74 5. Manageability Considerations . . . . . . . . . . . . . . . . . 6 75 6. Implementation Status . . . . . . . . . . . . . . . . . . . . 7 76 6.1. Centre Tecnologic de Telecomunicacions de Catalunya (CTTC) . 7 77 7. Security Considerations . . . . . . . . . . . . . . . . . . . 8 78 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 79 8.1. Grid Subregistry . . . . . . . . . . . . . . . . . . . . . . 9 80 8.2. DWDM Channel Spacing Subregistry . . . . . . . . . . . . . . 9 81 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 82 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 83 10.1. Normative References . . . . . . . . . . . . . . . . . . . 10 84 10.2. Informative References . . . . . . . . . . . . . . . . . . 10 85 Appendix A. Flexi-Grid Example . . . . . . . . . . . . . . . . . 11 86 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 87 Contributors' Addresses . . . . . . . . . . . . . . . . . . . . . 12 89 1. Introduction 91 As described in [RFC3945], GMPLS extends MPLS from supporting only 92 Packet Switching Capable (PSC) interfaces and switching, to also 93 support four new classes of interfaces and switching that include 94 Lambda Switch Capable (LSC). 96 A functional description of the extensions to MPLS signaling needed 97 to support this new class of interface and switching is provided in 99 [RFC3471]. 101 Section 3.2.1.1 of [RFC3471] states that wavelength labels "only have 102 significance between two neighbors": global wavelength semantics are 103 not considered. [RFC6205] defines a standard lambda label format 104 that has a global semantic and which is compliant with both the Dense 105 Wavelength Division Multiplexing (DWDM) grid [G.694.1] and the Coarse 106 Wavelength Division Multiplexing (CWDM) grid [G.694.2]. The terms 107 DWDM and CWDM are defined in [G.671]. 109 A flexible grid network selects its data channels as arbitrarily 110 assigned pieces of the spectrum. Mixed bitrate transmission systems 111 can allocate their channels with different spectral bandwidths so 112 that the channels can be optimized for the bandwidth requirements of 113 the particular bit rate and modulation scheme of the individual 114 channels. This technique is regarded as a promising way to improve 115 the network utilization efficiency and fundamentally reduce the cost 116 of the core network. 118 The "flexi-grid" has been developed within the ITU-T Study Group 15 119 to allow selection and switching of pieces of the optical spectrum 120 chosen flexibly from a fine granularity grid of wavelengths with 121 variable spectral bandwidth [G.694.1]. This document updates the 122 definition of GMPLS lambda labels provided in [RFC6205] to support 123 the flexi-grid. 125 This document relies on [G.694.1] for the definition of the optical 126 data plane and does not make any updates to the work of the ITU-T in 127 that regard. 129 1.1. Conventions Used in This Document 131 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 132 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 133 document are to be interpreted as described in [RFC2119]. 135 2. Overview of Flexi-Grid 137 [G.694.1] defines DWDM fixed grids. The latest version of that 138 document extends the DWDM fixed grids to add support for flexible 139 grids. The basis of the work is to allow a data channel to be formed 140 from an abstract grid anchored at 193.1 THz and selected on a channel 141 spacing of 6.25 GHz with a variable slot width measured in units of 142 12.5 GHz. Individual allocations may be made on this basis from 143 anywhere in the spectrum, subject to allocations not overlapping. 145 [G.694.1] provides clear guidance on the support of flexible grid by 146 implementations in Section 2 of Appendix I: 148 The flexible DWDM grid defined in clause 7 has a nominal central 149 frequency granularity of 6.25 GHz and a slot width granularity of 150 12.5 GHz. However, devices or applications that make use of the 151 flexible grid may not have to be capable of supporting every 152 possible slot width or position. In other words, applications may 153 be defined where only a subset of the possible slot widths and 154 positions are required to be supported. 156 For example, an application could be defined where the nominal 157 central frequency granularity is 12.5 GHz (by only requiring 158 values of n that are even) and that only requires slot widths as a 159 multiple of 25 GHz (by only requiring values of m that are even). 161 Some additional background on the use of GMPLS for flexible grids 162 can be found in [FLEXFWRK]. 164 3. Fixed Grid Lambda Label Encoding 166 [RFC6205] defines an encoding for a global semantic for a DWDM label 167 based on four fields: 169 - Grid: used to select which grid the lambda is selected from. 170 Values defined in [RFC6205] identify DWDM [G.694.1] and CWDM 171 [G.694.2]. 173 - C.S. (Channel Spacing): used to indicate the channel spacing. 174 [RFC6205] defines values to represent spacing of 100, 50, 25 and 175 12.5 GHz. 177 - Identifier: a local-scoped integer used to distinguish different 178 lasers (in one node) when they can transmit the same frequency 179 lambda. 181 - n: a two's-complement integer to take a positive, negative, or zero 182 value. This value is used to compute the frequency as defined in 183 [RFC6205] and based on [G.694.1]. The use of n is repeated here 184 for ease of reading the rest of this document: in case of 185 discrepancy, the definition in [RFC6205] is normative. 187 Frequency (THz) = 193.1 THz + n * frequency granularity (THz) 189 where the nominal central frequency granularity for the flexible 190 grid is 0.00625 THz 192 4. Flexi-Grid Label Format and Values 194 4.1 Flexi-Grid Label Encoding 196 This document defines a generalized label encoding for use in flexi- 197 grid systems. As with the other GMPLS lambda label formats defined 198 in [RFC3471] and [RFC6205], the use of this label format is known a 199 priori. That is, since the interpretation of all lambda labels is 200 determined hop-by-hop, the use of this label format requires that all 201 nodes on the path expect to use this label format. 203 For convenience, however, the label format is modeled on the fixed 204 grid label defined in [RFC6205] and briefly described in Section 3. 206 Figure 1 shows the format of the Flexi-Grid Label. It is a 64 bit 207 label. 209 0 1 2 3 210 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 1 211 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 212 |Grid | C.S. | Identifier | n | 213 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 214 | m | Reserved | 215 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 217 Figure 1 : The Flexi-Grid Label Encoding 219 This document defines a new Grid value to supplement those in 220 [RFC6205]: 222 +----------+---------+ 223 | Grid | Value | 224 +----------+---------+ 225 |ITU-T Flex| 3 | 226 +----------+---------+ 228 Within the fixed grid network, the C.S. value is used to represent 229 the channel spacing, as the spacing between adjacent channels is 230 constant. For the flexible grid situation, this field is used to 231 represent the nominal central frequency granularity. 233 This document defines a new C.S. value to supplement those in 234 [RFC6205]: 236 +----------+---------+ 237 | C.S(GHz) | Value | 238 +----------+---------+ 239 | 6.25 | 5 | 240 +----------+---------+ 242 The meaning of the Identifier field is maintained from [RFC6205] (see 243 also Section 3). 245 The meaning of n is maintained from [RFC6205] (see also Section 3). 247 The m field is used to identify the slot width according to the 248 formula given in [G.694.1] as follows. It is a 16 bit integer value 249 encoded in lne format. 251 Slot Width (GHz) = 12.5 GHz * m 253 The Reserved field MUST be set to zero on transmission and SHOULD be 254 ignored on receipt. 256 An implementation that wishes to use the flexi-grid label encoding 257 MUST follow the procedures of [RFC3473] and of [RFC3471] as updated 258 by [RFC6205]. It MUST set Grid to 3 and C.S. to 5. It MUST set 259 Identifier to indicate the local identifier of the laser in use as 260 described in [RFC6205]. It MUST also set n according to the formula 261 in Section 3 (inherited unchanged from [RFC6205]). Finally, the 262 implementation MUST set m as described in the formula stated above. 264 4.2. Considerations of Bandwidth 266 There is some overlap between the concepts of bandwidth and label in 267 many GMPLS-based systems where a label indicates a physical switching 268 resource. This overlap is increased in a flexi-grid system where a 269 label value indicates the slot width and so affects the bandwidth 270 supported by an LSP. Thus the 'm' parameter is both a property of 271 the label (i.e., it helps define exactly what is switched) and of the 272 bandwidth. 274 In GMPLS signaling [RFC3473], bandwidth is requested in the TSpec 275 object and confirmed in the Flowspec object. The 'm' parameter that 276 is a parameter of the GMPLS flexi-grid label as described above, is 277 also a parameter of the flexi-grid TSpec and Flowspec as described in 278 [FLEXRSVP]. 280 5. Manageability Considerations 282 This document introduces no new elements for management. That is, 283 labels can continue to be used in the same way by the GMPLS protocols 284 and where those labels were treated as opaque quantities with local 285 or global significance, no change is needed to the management 286 systems. 288 However, this document introduces some changes to the nature of a 289 label that may require changes to management systems. Firstly, 290 systems that handle lambda labels as 32 bit quantities need to be 291 updated to process the 64 bit labels described in this document even 292 if the labels are treated as opaque quantities. Furthermore, 293 although management systems that can handle lambda labels as defined 294 in [RFC6205] can continue to process the fields defined in RFC 6205 295 as before, they have to handle new legal values of some of those 296 fields (Grid = 3 and C.S. = 5), and they have to be aware of the new 297 'm' field. 299 6. Implementation Status 301 [RFC Editor Note: Please remove this entire seciton prior to publication 302 as an RFC.] 304 This section records the status of known implementations of the 305 protocol defined by this specification at the time of posting of this 306 Internet-Draft, and is based on a proposal described in RFC 6982 307 [RFC6982]. The description of implementations in this section is 308 intended to assist the IETF in its decision processes in progressing 309 drafts to RFCs. Please note that the listing of any individual 310 implementation here does not imply endorsement by the IETF. 311 Furthermore, no effort has been spent to verify the information 312 presented here that was supplied by IETF contributors. This is not 313 intended as, and must not be construed to be, a catalog of available 314 implementations or their features. Readers are advised to note that 315 other implementations may exist. 317 According to RFC 6982, "this will allow reviewers and working groups 318 to assign due consideration to documents that have the benefit of 319 running code, which may serve as evidence of valuable experimentation 320 and feedback that have made the implemented protocols more mature. 321 It is up to the individual working groups to use this information as 322 they see fit. 324 6.1. Centre Tecnologic de Telecomunicacions de Catalunya (CTTC) 326 Organization Responsible for the Implementation: 327 Centre Tecnologic de Telecomunicacions de Catalunya (CTTC) 328 Optical Networks and Systems Department 330 Implementation Name and Details: 331 ADRENALINE testbed 332 http://networks.cttc.es/experimental-testbeds/ 334 Brief Description: 335 Experimental testbed implementation of GMPLS/PCE control plane. 337 Level of Maturity: 338 Implemented as extensions to a mature GMLPS/PCE control plane. 339 It is limited to research / prototyping stages but it has been 340 used successfully for more than the last five years. 342 Coverage: 343 Support for the 64 bit label as described version 07 of this 344 document. 345 This affects mainly the implementation of RSVP-TE and PCEP 346 protocols: 347 - Generalized Label Support 348 - Suggested Label Support 349 - Upstream Label Support 350 - ERO Label Subobjects and Explicit Label Control 351 It is expected that this implementation will evolve to follow the 352 evolution of this document. 354 Licensing: 355 Proprietary 357 Implementation Experience: 358 Implementation of this document reports no issues. 359 General implementation experience has been reported in a number of 360 journal papers. Contact Ramon Casellas for more information or see 361 http://networks.cttc.es/publications/? 362 search=GMPLS&research_area=optical-networks-systems 364 Contact Information: 365 Ramon Casellas: ramon.casellas@cttc.es 367 Interoperability: 368 No report. 370 7. Security Considerations 372 [RFC6205] notes that the definition of a new label encoding does not 373 introduce any new security considerations to [RFC3471] and [RFC3473]. 374 That statement applies equally to this document. 376 For a general discussion on MPLS and GMPLS-related security issues, 377 see the MPLS/GMPLS security framework [RFC5920]. 379 8. IANA Considerations 381 IANA maintains the "Generalized Multi-Protocol Label Switching 382 (GMPLS) Signaling Parameters" registry that contains several 383 subregistries. 385 8.1. Grid Subregistry 387 IANA is requested to allocate a new entry in this subregistry as 388 follows: 390 Value Grid Reference 391 ----- ------------------------- ---------- 392 3 ITU-T Flex [This.I-D] 394 8.2. DWDM Channel Spacing Subregistry 396 IANA is requested to allocate a new entry in this subregistry as 397 follows: 399 Value Channel Spacing (GHz) Reference 400 ----- ------------------------- ---------- 401 5 6.25 [This.I-D] 403 9. Acknowledgments 405 This work was supported in part by the FP-7 IDEALIST project under 406 grant agreement number 317999. 408 Very many thanks to Lou Berger for discussions of labels of more than 409 32 bits. Many thanks to Sergio Belotti and Pietro Vittorio Grandi 410 for their support of this work. Thanks to Gabriele Galimberti for 411 discussion of the size of the "m" field. 413 Special thanks to the Vancouver 2012 Pool Party for discussions and 414 rough consensus: Dieter Beller, Ramon Casellas, Daniele Ceccarelli, 415 Oscar Gonzalez de Dios, Iftekhar Hussain, Cyril Margaria, Lyndon Ong, 416 and Fatai Zhang. 418 The authors would like to thank Ben Niven-Jenkins for inspiring the 419 choice of filename for this document. 421 10. References 423 10.1. Normative References 425 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 426 Requirement Levels", BCP 14, RFC 2119, March 1997. 428 [RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label 429 Switching (GMPLS) Signaling Functional Description", RFC 430 3471, January 2003. 432 [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label 433 Switching (GMPLS) Signaling Resource ReserVation Protocol- 434 Traffic Engineering (RSVP-TE) Extensions", RFC 3473, 435 January 2003. 437 [RFC6205] Otani, T., and Li, D., "Generalized Labels for Lambda- 438 Switch-Capable (LSC) Label Switching Routers", RFC 6205, 439 October 2011. 441 [G.694.1] ITU-T Recommendation G.694.1 (revision 2), "Spectral grids 442 for WDM applications: DWDM frequency grid", February 2012. 444 10.2. Informative References 446 [RFC3945] Mannie, E., Ed., "Generalized Multi-Protocol Label 447 Switching (GMPLS) Architecture", RFC 3945, October 2004. 449 [RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS 450 Networks", RFC 5920, July 2010. 452 [RFC6982] Sheffer, Y. and A. Farrel, "Improving Awareness of Running 453 Code: The Implementation Status Section", RFC 6982, July 454 2013. 455 [RFC Editor Note: This reference can be removed when Section 6 is 456 removed] 458 [G.671] ITU-T Recommendation G.671, "Transmission characteristics 459 of optical components and subsystems", 2009. 461 [G.694.2] ITU-T Recommendation G.694.2, "Spectral grids for WDM 462 applications: CWDM wavelength grid", December 2003. 464 [FLEXFWRK] O. Gonzalez de Dios, et al., "Framework and Requirements 465 for GMPLS based control of Flexi-grid DWDM networks", 466 draft-ogrcetal-ccamp-flexi-grid-fwk, work in progress. 468 [FLEXRSVP] Zhang, F., Gonzalez de Dios, O., and D. Ceccarelli, 469 "RSVP-TE Signaling Extensions in support of Flexible 470 Grid", draft-zhang-ccamp-flexible-grid-rsvp-te-ext, work 471 in progress. 473 Appendix A. Flexi-Grid Example 475 Consider a fragment of an optical LSP between node A and node B using 476 the flexible grid. Suppose that the LSP on this hop is formed: 477 - using the ITU-T Flexi-Grid 478 - the nominal central frequency of the slot 193.05 THz 479 - the nominal central frequency granularity is 6.25 GHz 480 - the slot width is 50 GHz. 482 In this case the label representing the switchable quantity that is 483 the flexi-grid quantity is encoded as described in Section 4.1 with 484 the following parameter settings. The label can be used in signaling 485 or in management protocols to describe the LSP. 487 Grid = 3 : ITU-T Flexi-Grid 489 C.S. = 5 : 6.25 GHz nominal central frequency granularity 491 Identifier = local value indicating the laser in use 493 n = -8 : 495 Frequency (THz) = 193.1 THz + n * frequency granularity (THz) 497 193.05 (THz) = 193.1 (THz) + n * 0.00625 (THz) 499 n = (193.05-193.1)/0.00625 = -8 501 m = 4 : 503 Slot Width (GHz) = 12.5 GHz * m 505 50 (GHz) = 12.5 (GHz) * m 507 m = 50 / 12.5 = 4 509 Authors' Addresses 511 Adrian Farrel 512 Old Dog Consulting 513 EMail: adrian@olddog.co.uk 515 Daniel King 516 Old Dog Consulting 517 EMail: daniel@olddog.co.uk 519 Yao Li 520 Nanjing University 521 EMail: wsliguotou@hotmail.com 523 Fatai Zhang 524 Huawei Technologies 525 EMail: zhangfatai@huawei.com 527 Contributors' Addresses 529 Zhang Fei 530 ZTE 531 EMail: zhang.fei3@zte.com.cn 533 Ramon Casellas 534 CTTC 535 EMail: ramon.casellas@cttc.es