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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: 10 March 2016 Nanjing University 7 F. Zhang 8 Huawei Technologies 10 10 September 2015 12 Generalized Labels for the Flexi-Grid in 13 Lambda Switch Capable (LSC) Label Switching Routers 15 draft-ietf-ccamp-flexigrid-lambda-label-05.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) 2015 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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 68 1.1. Conventions Used in This Document . . . . . . . . . . . . . 4 69 2. Overview of Flexi-Grid . . . . . . . . . . . . . . . . . . . . 4 70 2.1. Composite Labels . . . . . . . . . . . . . . . . . . . . . . 4 71 3. Fixed Grid Lambda Label Encoding . . . . . . . . . . . . . . . 5 72 4. Flexi-Grid Label Format and Values . . . . . . . . . . . . . . 5 73 4.1 Flexi-Grid Label Encoding . . . . . . . . . . . . . . . . . . 5 74 4.2. Considerations of Bandwidth . . . . . . . . . . . . . . . . 7 75 4.3. Composite Labels . . . . . . . . . . . . . . . . . . . . . . 7 76 5. Manageability and Backward Compatibility Considerations . . . 8 77 5.1. Control Plane Backward Compatibility . . . . . . . . . . . . 9 78 5.2. Manageability Considerations . . . . . . . . . . . . . . . . 9 79 6. Implementation Status . . . . . . . . . . . . . . . . . . . . 10 80 6.1. Centre Tecnologic de Telecomunicacions de Catalunya (CTTC) . 10 81 7. Security Considerations . . . . . . . . . . . . . . . . . . . 11 82 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 83 8.1. Grid Subregistry . . . . . . . . . . . . . . . . . . . . . . 12 84 8.2. DWDM Channel Spacing Subregistry . . . . . . . . . . . . . . 12 85 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 86 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 87 10.1. Normative References . . . . . . . . . . . . . . . . . . . 13 88 10.2. Informative References . . . . . . . . . . . . . . . . . . 13 89 Appendix A. Flexi-Grid Example . . . . . . . . . . . . . . . . . 15 90 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16 91 Contributors' Addresses . . . . . . . . . . . . . . . . . . . . . 16 93 1. Introduction 95 As described in [RFC3945], GMPLS extends MPLS from supporting only 96 Packet Switch Capable (PSC) interfaces and switching, to also support 97 four new classes of interfaces and switching that include Lambda 98 Switch Capable (LSC). 100 A functional description of the extensions to MPLS signaling needed 101 to support this new class of interface and switching is provided in 102 [RFC3471]. 104 Section 3.2.1.1 of [RFC3471] states that wavelength labels "only have 105 significance between two neighbors": global wavelength semantics are 106 not considered. [RFC6205] defines a standard lambda label format 107 that has a global semantic and which is compliant with both the Dense 108 Wavelength Division Multiplexing (DWDM) grid [G.694.1] and the Coarse 109 Wavelength Division Multiplexing (CWDM) grid [G.694.2]. The terms 110 DWDM and CWDM are defined in [G.671]. 112 A flexible grid network selects its data channels as arbitrarily 113 assigned pieces of the spectrum. Mixed bitrate transmission systems 114 can allocate their channels with different spectral bandwidths so 115 that the channels can be optimized for the bandwidth requirements of 116 the particular bit rate and modulation scheme of the individual 117 channels. This technique is regarded as a promising way to improve 118 the network utilization efficiency and fundamentally reduce the cost 119 of the core network. 121 The "flexi-grid" has been developed within the ITU-T Study Group 15 122 to allow selection and switching of pieces of the optical spectrum 123 chosen flexibly from a fine granularity grid of wavelengths with 124 variable spectral bandwidth [G.694.1]. 126 [RFC3471] defines several basic label types including the lambda 127 label. [RFC3471] states that wavelength labels "only have 128 significance between two neighbors" (Section 3.2.1.1); global 129 wavelength semantics are not considered. In order to facilitate 130 interoperability in a network composed of LSC equipment, [RFC6205] 131 defines a standard lambda label format and is designated an update of 132 RFC 3471. 134 This document continues the theme of defining global semantics for 135 the wavelength label by adding support for the flexi-grid. Thus, 136 this document updates [RFC6205] and [RFC3471]. 138 This document relies on [G.694.1] for the definition of the optical 139 data plane and does not make any updates to the work of the ITU-T. 141 1.1. Conventions Used in This Document 143 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 144 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 145 document are to be interpreted as described in [RFC2119]. 147 2. Overview of Flexi-Grid 149 [G.694.1] defines DWDM fixed grids. The latest version of that 150 document extends the DWDM fixed grids to add support for flexible 151 grids. The basis of the work is to allow a data channel to be formed 152 from an abstract grid anchored at 193.1 THz and selected on a channel 153 spacing of 6.25 GHz with a variable slot width measured in units of 154 12.5 GHz. Individual allocations may be made on this basis from 155 anywhere in the spectrum, subject to allocations not overlapping. 157 [G.694.1] provides clear guidance on the support of flexible grid by 158 implementations in Section 2 of Appendix I: 160 The flexible DWDM grid defined in clause 7 has a nominal central 161 frequency granularity of 6.25 GHz and a slot width granularity of 162 12.5 GHz. However, devices or applications that make use of the 163 flexible grid may not have to be capable of supporting every 164 possible slot width or position. In other words, applications may 165 be defined where only a subset of the possible slot widths and 166 positions are required to be supported. 168 For example, an application could be defined where the nominal 169 central frequency granularity is 12.5 GHz (by only requiring 170 values of n that are even) and that only requires slot widths as a 171 multiple of 25 GHz (by only requiring values of m that are even). 173 Some additional background on the use of GMPLS for flexible grids 174 can be found in [FLEXFWRK]. 176 2.1. Composite Labels 178 It is possible to construct an end-to-end connection as a composite 179 of more than one flexi-grid slot. The mechanism used in GMPLS is 180 similar to that used to support inverse multiplexing familiar in 181 time-division multiplexing (TDM) and optical transport networks 182 (OTN). The slots in the set could potentially be contiguous or non- 183 contiguous (only as allowed by the definitions of the data plane) and 184 could be signaled as a single LSP or constructed from a group of 185 LSPs. For more details, refer to Section 4.3. 187 How the signal is carried across such groups of channels is out of 188 scope for this document. 190 3. Fixed Grid Lambda Label Encoding 192 [RFC6205] defines an encoding for a global semantic for a DWDM label 193 based on four fields: 195 - Grid: used to select which grid the lambda is selected from. 196 Values defined in [RFC6205] identify DWDM [G.694.1] and CWDM 197 [G.694.2]. 199 - C.S. (Channel Spacing): used to indicate the channel spacing. 200 [RFC6205] defines values to represent spacing of 100, 50, 25 and 201 12.5 GHz. 203 - Identifier: a local-scoped integer used to distinguish different 204 lasers (in one node) when they can transmit the same frequency 205 lambda. 207 - n: a two's-complement integer to take a positive, negative, or zero 208 value. This value is used to compute the frequency as defined in 209 [RFC6205] and based on [G.694.1]. The use of n is repeated here 210 for ease of reading the rest of this document: in case of 211 discrepancy, the definition in [RFC6205] is normative. 213 Frequency (THz) = 193.1 THz + n * frequency granularity (THz) 215 where the nominal central frequency granularity for the flexible 216 grid is 0.00625 THz 218 4. Flexi-Grid Label Format and Values 220 4.1 Flexi-Grid Label Encoding 222 This document defines a generalized label encoding for use in flexi- 223 grid systems. As with the other GMPLS lambda label formats defined 224 in [RFC3471] and [RFC6205], the use of this label format is known a 225 priori. That is, since the interpretation of all lambda labels is 226 determined hop-by-hop, the use of this label format requires that all 227 nodes on the path expect to use this label format. 229 For convenience, however, the label format is modeled on the fixed 230 grid label defined in [RFC6205] and briefly described in Section 3. 232 Figure 1 shows the format of the Flexi-Grid Label. It is a 64 bit 233 label. 235 0 1 2 3 236 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 1 237 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 238 |Grid | C.S. | Identifier | n | 239 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 240 | m | Reserved | 241 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 243 Figure 1 : The Flexi-Grid Label Encoding 245 This document defines a new Grid value to supplement those in 246 [RFC6205]: 248 +----------+---------+ 249 | Grid | Value | 250 +----------+---------+ 251 |ITU-T Flex| 3 | 252 +----------+---------+ 254 Within the fixed grid network, the C.S. value is used to represent 255 the channel spacing, as the spacing between adjacent channels is 256 constant. For the flexible grid situation, this field is used to 257 represent the nominal central frequency granularity. 259 This document defines a new C.S. value to supplement those in 260 [RFC6205]: 262 +----------+---------+ 263 | C.S(GHz) | Value | 264 +----------+---------+ 265 | 6.25 | 5 | 266 +----------+---------+ 268 The meaning of the Identifier field is maintained from [RFC6205] (see 269 also Section 3). 271 The meaning of n is maintained from [RFC6205] (see also Section 3). 273 The m field is used to identify the slot width according to the 274 formula given in [G.694.1] as follows. It is a 16 bit integer value 275 encoded in line format. 277 Slot Width (GHz) = 12.5 GHz * m 279 The Reserved field MUST be set to zero on transmission and SHOULD be 280 ignored on receipt. 282 An implementation that wishes to use the flexi-grid label encoding 283 MUST follow the procedures of [RFC3473] and of [RFC3471] as updated 284 by [RFC6205]. It MUST set Grid to 3 and C.S. to 5. It MUST set 285 Identifier to indicate the local identifier of the laser in use as 286 described in [RFC6205]. It MUST also set n according to the formula 287 in Section 3 (inherited unchanged from [RFC6205]). Finally, the 288 implementation MUST set m as described in the formula stated above. 290 4.2. Considerations of Bandwidth 292 There is some overlap between the concepts of bandwidth and label in 293 many GMPLS-based systems where a label indicates a physical switching 294 resource. This overlap is increased in a flexi-grid system where a 295 label value indicates the slot width and so affects the bandwidth 296 supported by an LSP. Thus the 'm' parameter is both a property of 297 the label (i.e., it helps define exactly what is switched) and of the 298 bandwidth. 300 In GMPLS signaling [RFC3473], bandwidth is requested in the TSpec 301 object and confirmed in the Flowspec object. The 'm' parameter that 302 is a parameter of the GMPLS flexi-grid label as described above, is 303 also a parameter of the flexi-grid TSpec and Flowspec as described in 304 [FLEXRSVP]. 306 4.3. Composite Labels 308 The creation of a composite of multiple channels to support inverse 309 multiplexing is already supported in GMPLS for TDM and OTN [RFC4606], 310 [RFC6344], [RFC7139]. The mechanism used for flexi-grid is similar. 312 To signal an LSP that uses multiple flexi-grid slots a "compound 313 label" is constructed. That is, the LABEL object is constructed from 314 a concatenation of the 64-bit Flexi-Grid Labels shown in Figure 1. 315 The number of elements in the label can be determined from the length 316 of the LABEL object. The resulting LABEL object is shown in Figure 317 2 including the object header that is not normally shown in 318 diagrammatic representations of RSVP-TE objects. Note that r is the 319 count of component labels, and this is backward compatible with the 320 label shown in Figure 1 where the value of r is 1. 322 The order of component labels MUST be presented in increasing order 323 of the value n. Implementations MUST NOT infer anything about the 324 encoding of a signal into the set of slots represented by a compound 325 label from the label itself. Information about the encoding MAY be 326 handled in other fields in signaling messages or through an out of 327 band system, but such considerations are out of the scope of this 328 document. 330 0 1 2 3 331 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 1 332 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 333 | Object Length (4 + 8r) | Class-Num (16)| C-Type (2) | 334 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 335 |Grid | C.S. | Identifier | n | 336 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 337 | m | Reserved | 338 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 339 ~ ~ 340 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 341 |Grid | C.S. | Identifier | n | 342 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 343 | m | Reserved | 344 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 346 Figure 2 : A Compound Label for Virtual Concatenation 348 Note that specific rules must be applied as follows: 350 - Grid MUST show "ITU-T Flex" value 3 in each component label. 351 - C.S. MUST have the same value in each component label. 352 - Identifier in each component label may identify different physical 353 equipment. 354 - Values of n and m in each component label define the slots that 355 are concatenated. 357 At the time of writing [G.694.1] only supports only groupings of 358 adjacent slots (i.e., without intervening unused slots that could be 359 used for other purposes) of identical width (same value of m), and 360 the component slots must be in increasing order of frequency (i.e., 361 increasing order of the value n). The mechanism defined here MUST 362 NOT be used for other forms of grouping unless and until those forms 363 are defined and documented in Recommendations published by the ITU-T. 365 Note further that while the mechanism described here naturally means 366 that all component channels are corouted, a composite channel can 367 also be achieved by constructing individual LSPs from single flexi- 368 grid slots and managing those LSPs as a group. A mechanism for 369 achieving this for TDM is described in [RFC6344], but is out of scope 370 for discussion in this document because the labels used are normal, 371 single slot labels and require no additional definitions. 373 5. Manageability and Backward Compatibility Considerations 375 This section briefly considers issues of manageability and backward 376 compatibility. 378 5.1. Control Plane Backward Compatibility 380 Labels are carried in two ways in GMPLS: for immediate use on the 381 next hop and for use at remote hops. 383 It is an assumption of GMPLS that both ends of a link know what 384 label types are supported and only use appropriate label types. If 385 a label of an unknown type is received it will be processed as if it 386 was of a known type since the Label Object and similar label-carrying 387 objects do not contain a type identifier. Thus the introduction of a 388 flexi-grid label in this document does not change the compatibility 389 issues and a legacy node that does not support the new flexi-grid 390 label should not expect to receive or handle such labels. If one is 391 incorrectly used in communication with a legacy node it will attempt 392 to process it as an expected label type with a potentially poor 393 outcome. 395 It is possible that a GMPLS message transitting a legacy node will 396 contain a flexi-grid label destined for or reported by a remote node. 397 For example, an LSP that transits links of different technologies 398 might record flexi-grid labels in a Record Route Object that is 399 subsequently passed to a legacy node. Such labels will not have any 400 impact on legacy implementations except as noted in the manageability 401 considerations in the next section. 403 5.2. Manageability Considerations 405 This document introduces no new elements for management. That is, 406 labels can continue to be used in the same way by the GMPLS protocols 407 and where those labels were treated as opaque quantities with local 408 or global significance, no change is needed to the management 409 systems. 411 However, this document introduces some changes to the nature of a 412 label that may require changes to management systems. Although 413 Section 3.2 of [RFC3471] makes clear that a label is of variable 414 length according to the type and that the type is supposed to be 415 known a priori by both ends of a link, a management system is not 416 guaranteed to be updated in step with upgrades or installations of 417 new flexi-grid functionality in the network. 419 But an implementation expecting a 32 bit lambda label would not fail 420 ungracefully because the first 32 bits follow the format of 421 [RFC6205]. It would look at theses labels and read but not recognize 422 the new grid type value. It would then give up trying to parse the 423 label and (presumably) the whole of the rest of the message. 425 The management system can be upgraded in two steps: 427 - Firstly, systems that handle lambda labels as 32 bit quantities 428 need to be updated to handle the increase length (64 bits) of 429 labels as described in this document. These "unknown" 64 bit 430 labels could be displayed as opaque 64 bit quantities and still add 431 a lot of value for the operator (who might need to parse the label 432 by hand). However, an implementation that already supports lambda 433 labels as defined in [RFC6205] can safely continue to process the 434 first 32 bits and display the fields defined in RFC 6205 as before 435 leaving just the second 32 bits as opaque data. 437 - Second, a more sophisticated upgrade to a management system would 438 fully parse the flex-gird labels and display them field-by-field as 439 described in this document. 441 6. Implementation Status 443 [RFC Editor Note: Please remove this entire section prior to publication 444 as an RFC.] 446 This section records the status of known implementations of the 447 protocol defined by this specification at the time of posting of this 448 Internet-Draft, and is based on a proposal described in RFC 6982 449 [RFC6982]. The description of implementations in this section is 450 intended to assist the IETF in its decision processes in progressing 451 drafts to RFCs. Please note that the listing of any individual 452 implementation here does not imply endorsement by the IETF. 453 Furthermore, no effort has been spent to verify the information 454 presented here that was supplied by IETF contributors. This is not 455 intended as, and must not be construed to be, a catalog of available 456 implementations or their features. Readers are advised to note that 457 other implementations may exist. 459 According to RFC 6982, "this will allow reviewers and working groups 460 to assign due consideration to documents that have the benefit of 461 running code, which may serve as evidence of valuable experimentation 462 and feedback that have made the implemented protocols more mature. 463 It is up to the individual working groups to use this information as 464 they see fit." 466 6.1. Centre Tecnologic de Telecomunicacions de Catalunya (CTTC) 468 Organization Responsible for the Implementation: 469 Centre Tecnologic de Telecomunicacions de Catalunya (CTTC) 470 Optical Networks and Systems Department 472 Implementation Name and Details: 473 ADRENALINE testbed 474 http://networks.cttc.es/experimental-testbeds/ 476 Brief Description: 477 Experimental testbed implementation of GMPLS/PCE control plane. 479 Level of Maturity: 480 Implemented as extensions to a mature GMLPS/PCE control plane. 481 It is limited to research / prototyping stages but it has been 482 used successfully for more than the last five years. 484 Coverage: 485 Support for the 64 bit label as described version 07 of this 486 document. 487 This affects mainly the implementation of RSVP-TE and PCEP 488 protocols: 490 - Generalized Label Support 491 - Suggested Label Support 492 - Upstream Label Support 493 - ERO Label Subobjects and Explicit Label Control 494 It is expected that this implementation will evolve to follow the 495 evolution of this document. 497 Licensing: 498 Proprietary 500 Implementation Experience: 501 Implementation of this document reports no issues. 502 General implementation experience has been reported in a number of 503 journal papers. Contact Ramon Casellas for more information or see 504 http://networks.cttc.es/publications/? 505 search=GMPLS&research_area=optical-networks-systems 507 Contact Information: 508 Ramon Casellas: ramon.casellas@cttc.es 510 Interoperability: 511 No report. 513 7. Security Considerations 515 [RFC6205] notes that the definition of a new label encoding does not 516 introduce any new security considerations to [RFC3471] and [RFC3473]. 517 That statement applies equally to this document. 519 For a general discussion on MPLS and GMPLS-related security issues, 520 see the MPLS/GMPLS security framework [RFC5920]. 522 8. IANA Considerations 524 IANA maintains the "Generalized Multi-Protocol Label Switching 525 (GMPLS) Signaling Parameters" registry that contains several 526 subregistries. 528 8.1. Grid Subregistry 530 IANA is requested to allocate a new entry in this subregistry as 531 follows: 533 Value Grid Reference 534 ----- ------------------------- ---------- 535 3 ITU-T Flex [This.I-D] 537 8.2. DWDM Channel Spacing Subregistry 539 IANA is requested to allocate a new entry in this subregistry as 540 follows: 542 Value Channel Spacing (GHz) Reference 543 ----- ------------------------- ---------- 544 5 6.25 [This.I-D] 546 9. Acknowledgments 548 This work was supported in part by the FP-7 IDEALIST project under 549 grant agreement number 317999. 551 Very many thanks to Lou Berger for discussions of labels of more than 552 32 bits. Many thanks to Sergio Belotti and Pietro Vittorio Grandi 553 for their support of this work. Thanks to Gabriele Galimberti for 554 discussion of the size of the "m" field, and to Iftekhar Hussain for 555 discussion of composite labels. Robert Sparks, Carlos Pignataro, and 556 Paul Wouters provided review comments during IETF last call. 558 Special thanks to the Vancouver 2012 Pool Party for discussions and 559 rough consensus: Dieter Beller, Ramon Casellas, Daniele Ceccarelli, 560 Oscar Gonzalez de Dios, Iftekhar Hussain, Cyril Margaria, Lyndon Ong, 561 Fatai Zhang, and Adrian Farrel. 563 10. References 565 10.1. Normative References 567 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 568 Requirement Levels", BCP 14, RFC 2119, March 1997. 570 [RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label 571 Switching (GMPLS) Signaling Functional Description", RFC 572 3471, January 2003. 574 [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label 575 Switching (GMPLS) Signaling Resource ReserVation Protocol- 576 Traffic Engineering (RSVP-TE) Extensions", RFC 3473, 577 January 2003. 579 [RFC6205] Otani, T., and Li, D., "Generalized Labels for Lambda- 580 Switch-Capable (LSC) Label Switching Routers", RFC 6205, 581 October 2011. 583 [G.694.1] ITU-T Recommendation G.694.1 (revision 2), "Spectral grids 584 for WDM applications: DWDM frequency grid", February 2012. 586 10.2. Informative References 588 [RFC3945] Mannie, E., Ed., "Generalized Multi-Protocol Label 589 Switching (GMPLS) Architecture", RFC 3945, October 2004. 591 [RFC4606] Mannie, E., and Papadimitriou, D., "Generalized Multi- 592 Protocol Label Switching (GMPLS) Extensions for 593 Synchronous Optical Network (SONET) and Synchronous 594 Digital Hierarchy (SDH) Control", RFC 4606, August 2006. 596 [RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS 597 Networks", RFC 5920, July 2010. 599 [RFC6344] Bernstein, G., Caviglia, D., Rabbat, R., and van Helvoort, 600 H., "Operating Virtual Concatenation (VCAT) and the Link 601 Capacity Adjustment Scheme (LCAS) with Generalized Multi- 602 Protocol Label Switching (GMPLS)", RFC 6344, August 2011. 604 [RFC6982] Sheffer, Y. and A. Farrel, "Improving Awareness of Running 605 Code: The Implementation Status Section", RFC 6982, July 606 2013. 607 [RFC Editor Note: This reference can be removed when Section 6 is 608 removed] 610 [RFC7139] Zhang, F., Zhang, G., Belotti, S., Ceccarelli, D., and 611 Pithewan, K., "GMPLS Signaling Extensions for Control of 612 Evolving G.709 Optical Transport Networks", RFC 7139, 613 March 2014. 615 [G.671] ITU-T Recommendation G.671, "Transmission characteristics 616 of optical components and subsystems", 2009. 618 [G.694.2] ITU-T Recommendation G.694.2, "Spectral grids for WDM 619 applications: CWDM wavelength grid", December 2003. 621 [FLEXFWRK] O. Gonzalez de Dios, et al., "Framework and Requirements 622 for GMPLS based control of Flexi-grid DWDM networks", 623 draft-ogrcetal-ccamp-flexi-grid-fwk, work in progress. 625 [FLEXRSVP] Zhang, F., Gonzalez de Dios, O., and D. Ceccarelli, 626 "RSVP-TE Signaling Extensions in support of Flexible 627 Grid", draft-zhang-ccamp-flexible-grid-rsvp-te-ext, work 628 in progress. 630 Appendix A. Flexi-Grid Example 632 Consider a fragment of an optical LSP between node A and node B using 633 the flexible grid. Suppose that the LSP on this hop is formed: 634 - using the ITU-T Flexi-Grid 635 - the nominal central frequency of the slot 193.05 THz 636 - the nominal central frequency granularity is 6.25 GHz 637 - the slot width is 50 GHz. 639 In this case the label representing the switchable quantity that is 640 the flexi-grid quantity is encoded as described in Section 4.1 with 641 the following parameter settings. The label can be used in signaling 642 or in management protocols to describe the LSP. 644 Grid = 3 : ITU-T Flexi-Grid 646 C.S. = 5 : 6.25 GHz nominal central frequency granularity 648 Identifier = local value indicating the laser in use 650 n = -8 : 652 Frequency (THz) = 193.1 THz + n * frequency granularity (THz) 654 193.05 (THz) = 193.1 (THz) + n * 0.00625 (THz) 656 n = (193.05-193.1)/0.00625 = -8 658 m = 4 : 660 Slot Width (GHz) = 12.5 GHz * m 662 50 (GHz) = 12.5 (GHz) * m 664 m = 50 / 12.5 = 4 666 Authors' Addresses 668 Adrian Farrel 669 Old Dog Consulting 670 EMail: adrian@olddog.co.uk 672 Daniel King 673 Old Dog Consulting 674 EMail: daniel@olddog.co.uk 676 Yao Li 677 Nanjing University 678 EMail: wsliguotou@hotmail.com 680 Fatai Zhang 681 Huawei Technologies 682 EMail: zhangfatai@huawei.com 684 Contributors' Addresses 686 Zhang Fei 687 Huawei Technologies 688 EMail: zhangfei7@huawei.com 690 Ramon Casellas 691 CTTC 692 EMail: ramon.casellas@cttc.es