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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Network Working Group Tomohiro Otani(Ed.) 2 Internet Draft KDDI 3 Updates: RFC3471 Dan Li(Ed.) 4 Category: Standards Track Huawei 6 Expires: October 2010 April 8, 2010 8 Generalized Labels for Lambda-Switching Capable Label Switching 9 Routers 11 draft-ietf-ccamp-gmpls-g-694-lambda-labels-07.txt 13 Status of this Memo 15 This Internet-Draft is submitted to IETF in full conformance with the 16 provisions of BCP 78 and BCP 79. 18 Internet-Drafts are working documents of the Internet Engineering 19 Task Force (IETF), its areas, and its working groups. Note that other 20 groups may also distribute working documents as Internet-Drafts. 22 Internet-Drafts are draft documents valid for a maximum of six months 23 and may be updated, replaced, or obsoleted by other documents at any 24 time. It is inappropriate to use Internet-Drafts as reference 25 material or to cite them other than as "work in progress." 27 The list of current Internet-Drafts can be accessed at 28 http://www.ietf.org/ietf/1id-abstracts.txt 30 The list of Internet-Draft Shadow Directories can be accessed at 31 http://www.ietf.org/shadow.html 33 This Internet-Draft will expire on September 30, 2010. 35 Copyright Notice 37 Copyright (c) 2010 IETF Trust and the persons identified as the 38 document authors. All rights reserved. 40 This document is subject to BCP 78 and the IETF Trust's Legal 41 Provisions Relating to IETF Documents 42 (http://trustee.ietf.org/license-info) in effect on the date of 43 publication of this document. Please review these documents carefully, 44 as they describe your rights and restrictions with respect to this 45 document. Code Components extracted from this document must include 46 Simplified BSD License text as described in Section 4.e of the Trust 47 Legal Provisions and are provided without warranty as described in 48 the Simplified BSD License. 50 Abstract 52 Technology in the optical domain is constantly evolving and as a 53 consequence new equipment providing lambda switching capability has 54 been developed and is currently being deployed. However, [RFC3471] 55 has defined that a wavelength label (section 3.2.1.1) "only has 56 significance between two neighbors" and global wavelength continuity 57 is not considered. In order to achieve interoperability in a network 58 composed of next generation lambda switch-capable equipment, this 59 document defines a standard lambda label format, being compliant 60 with either [G.694.1](DWDM-grid) or [G.694.2](CWDM-grid). Moreover 61 some consideration on how to ensure lambda continuity with RSVP-TE 62 is provided. This document is a companion to the Generalized Multi- 63 Protocol Label Switching (GMPLS) signaling. It defines the label 64 format when Lambda Switching is requested in an all optical network. 66 Conventions used in this document 68 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 69 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 70 document are to be interpreted as described in [RFC2119]. 72 Table of Contents 74 1. Introduction.................................................3 75 2. Assumed network model and related problem statement..........3 76 3. Label Related Formats........................................6 77 3.1. Wavelength Labels.......................................6 78 3.2. DWDM Wavelength Label...................................7 79 3.3. CWDM Wavelength Label...................................8 80 4. Security Considerations.....................................10 81 5. IANA Considerations.........................................10 82 6. Acknowledgments.............................................10 83 7. References..................................................10 84 7.1. Normative References...................................10 85 7.2. Informative References.................................11 86 8. Author's Address............................................12 87 9. Appendix A. DWDM Example....................................13 88 10. Appendix B. CWDM Example...................................13 90 1. Introduction 92 As described in [RFC3945], Generalized MPLS (GMPLS) extends MPLS 93 from supporting only packet (Packet Switching Capable - PSC) 94 interfaces and switching to also include support for four new 95 classes of interfaces and switching: 97 o Layer-2 Switch Capable (L2SC) 99 o Time-Division Multiplex (TDM) 101 o Lambda Switch Capable (LSC) 103 o Fiber-Switch Capable (FSC). 105 A functional description of the extensions to MPLS signaling needed 106 to support new classes of interfaces and switching is provided in 107 [RFC3471]. 109 This document presents details that are specific to the use of GMPLS 110 with a new generation of Lambda Switch Capable (LSC) equipment. 111 Technologies such as Reconfigurable Optical Add/Drop Multiplex (ROADM) 112 and Wavelength Cross-Connect (WXC) operate at the wavelength 113 switching level. As such, the wavelength is important information 114 that is necessary to set up a wavelength-based LSP appropriately and 115 the wavelength defined in [G.694.1] or [G.694.2] is widely utilized. 117 2. Assumed network model and related problem statement 119 Figure 1 depicts an all-optically switched network consisting of 120 different vendor's optical network domains. Vendor A's network 121 consists of ROADM or WXC, and vendor B's network consists of number 122 of photonic cross-connect (PXC) and Dense wavelength division 123 multiplexing (DWDM) multiplexer & demultiplexer, otherwise both 124 vendors' networks might be based on the same technology. 126 In this case, the use of standardized wavelength label information is 127 quite significant to establish a wavelength-based LSP. It is also an 128 important constraint when conducting CSPF calculation for RSVP-TE 129 signaling. The way the Constrained Shortest Path First (CSPF) is 130 performed is outside the scope of this document. 132 It is needless to say, a LSP must be appropriately provisioned 133 between a selected pair of ports not only within Domain A but also 134 over multiple domains satisfying wavelength constraints. 136 Figure 2 illustrates in detail the interconnection between Domain A 137 and Domain B. 139 | 140 Domain A (or Vendor A) | Domain B (or Vendor B) 141 | 142 Node-1 Node-2 | Node-6 Node-7 143 +--------+ +--------+ | +-------+ +-+ +-+ +-------+ 144 | ROADM | | ROADM +---|------+ PXC +-+D| |D+-+ PXC | 145 | or WXC +========+ or WXC +---|------+ +-+W+=====+W+-+ | 146 | (LSC) | | (LSC) +---|------+ (LSC) +-+D| |D+-+ (LSC) | 147 +--------+ +--------+ | | +-|M| |M+-+ | 148 || || | +++++++++ +-+ +-+ +++++++++ 149 || Node-3 || | ||||||| ||||||| 150 || +--------+ || | +++++++++ +++++++++ 151 ||===| WXC +===|| | | DWDM | | DWDM | 152 | (LSC) | | +--++---+ +--++---+ 153 ||===+ +===|| | || || 154 || +--------+ || | +--++---+ +--++---+ 155 || || | | DWDM | | DWDM | 156 +--------+ +--------+ | +++++++++ +++++++++ 157 | ROADM | | ROADM | | ||||||| ||||||| 158 | or WXC +========+ or WXC +=+ | +-+ +++++++++ +-+ +-+ +++++++++ 159 | (LSC) | | (LSC) | | | |D|-| PXC +-+D| |D+-+ PXC | 160 +--------+ +--------+ +=|==+W|-| +-+W+=====+W+-+ | 161 Node-4 Node-5 | |D|-| (LSC) +-+D| |D+-+ (LSC) | 162 | |M|-| +-+M| |M+-+ | 163 | +-+ +-------+ +-+ +-+ +-------+ 164 | Node-8 Node-9 166 Figure 1 Wavelength-based network model 168 +-------------------------------------------------------------+ 169 | Domain A | Domain B | 170 | | | 171 | +---+ lambda 1 | +---+ | 172 | | |---------------|---------| | | 173 | WDM | N | lambda 2 | | N | WDM | 174 | =====| O |---------------|---------| O |===== | 175 | O | D | . | | D | O | 176 | T WDM | E | . | | E | WDM T | 177 | H =====| 2 | lambda n | | 6 |===== H | 178 | E | |---------------|---------| | E | 179 | R +---+ | +---+ R | 180 | | | 181 | N +---+ | +---+ N | 182 | O | | | | | O | 183 | D WDM | N | | | N | WDM D | 184 | E =====| O | WDM | | O |===== E | 185 | S | D |=========================| D | S | 186 | WDM | E | | | E | WDM | 187 | =====| 5 | | | 8 |===== | 188 | | | | | | | 189 | +---+ | +---+ | 190 +-------------------------------------------------------------+ 192 Figure 2 Interconnecting details between two domains 194 In the scenario of Figure 1, consider the setting up of a 195 bidirectional LSP from ingress switch 1 to egress switch 9. In order 196 to satisfy wavelength continuity constraint, a fixed wavelength 197 (lambda 1) needs to be used in domain A and domain B. A Path message 198 will be used for the signaling, the PATH message must contain the 199 upstream label and a label set object; both containing the same 200 lambda. The label set object is made by only one sub channel that 201 must be same as the upstream label. The path setup will continue 202 downstream to switch 9 by configuring each lambda switch based on the 203 wavelength label. This label allows the correct switching of lambda 204 switches and the label contents needs to be used over the inter- 205 domain. As same above, the path setup will continue downstream to 206 switch 9 by configuring lambda switch based on multiple wavelength 207 labels. If the node has a tunable wavelength transponder, the tuning 208 wavelength is considered as a part of wavelength switching operation. 210 Not using a standardized label would add undue burden on the operator 211 to enforce policy as each manufacturer may decide on a different 212 representation and therefore each domain may have its own label 213 formats. Moreover, manual provisioning may lead to misconfiguration 214 if domain-specific labels are used. 216 Therefore, a wavelength label should be standardized in order to 217 allow interoperability between multiple domains; otherwise 218 appropriate existing labels are identified in support of wavelength 219 availability. As identical wavelength information, the ITU-T 220 frequency grid specified in [G.694.1] for Dense WDM (DWDM) and 221 wavelength information in [G.694.2] for Coarse WDM (CWDM) are used by 222 LSRs and should be followed as a wavelength label. 224 3. Label Related Formats 226 To deal with the widening scope of MPLS into the optical and time 227 domains, several new forms of "label" have been defined in [RFC3471]. 228 This section contains clarifications for the Wavelength label based 229 on [G.694.1] or [G.694.2] and Label Set definition specific for LSC 230 LSRs. 232 3.1. Wavelength Labels 234 In section 3.2.1.1 of [RFC3471], a Wavelength label is defined to 235 have significance between two neighbors, and the receiver may need to 236 convert the received value into a value that has local significance. 238 LSC equipment uses multiple wavelengths controlled by a single 239 control channel. In such case, the label indicates the wavelength to 240 be used for the LSP. This document proposes to standardize the 241 wavelength label. As an example of wavelength values, the reader is 242 referred to [G.694.1] which lists the frequencies from the ITU-T DWDM 243 frequency grid. The same can be done for CWDM technology by using 244 the wavelength defined in [G.694.2]. In that sense, we can call 245 wavelength labels. 247 Since the ITU-T DWDM grid is based on nominal central frequencies, we 248 need to indicate the appropriate table, the channel spacing in the 249 grid and a value n that allows the calculation of the frequency. That 250 value can be positive or negative. 252 The frequency is calculated as such in [G.694.1]: 254 Frequency (THz) = 193.1 THz + n * channel spacing (THz) 256 , where n is a two's-complement integer (positive, negative or 0) and 257 channel spacing is defined to be 0.0125, 0.025, 0.05 or 0.1 THz. When 258 wider channel spacing such as 0.2 THz is utilized, the combination of 259 narrower channel spacing and the value n can provide proper frequency 260 with that channel spacing. Channel spacing is not utilized to 261 indicate the LSR capability but only to specify a frequency in 262 signaling. 264 For the other example of the case of the ITU-T CWDM grid, the spacing 265 between different channels was defined to be 20nm, so we need to pass 266 the wavelength value in nm in this case. Examples of CWDM wavelengths 267 are 1471, 1491, etc. nm. 269 The wavelength is calculated as follows 271 Wavelength (nm) = 1471 nm + n * 20 nm 273 , where n is a two's-complement integer (positive, negative or 0). 274 The grids listed in [G.694.1] and [G.694.2] are not numbered and 275 change with the changing frequency spacing as technology advances, so 276 an index is not appropriate in this case. 278 3.2. DWDM Wavelength Label 280 For the case of DWDM, the information carried in a Wavelength label 281 is: 283 0 1 2 3 284 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 1 285 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 286 |Grid | C.S | Identifier | n | 287 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 289 (1) Grid: 3 bits 291 The value for grid is set to 1 for ITU-T DWDM Grid as defined in 292 [G.694.1]. 294 +----------+---------+ 295 | Grid | Value | 296 +----------+---------+ 297 | Reserved | 0 | 298 +----------+---------+ 299 |ITU-T DWDM| 1 | 300 +----------+---------+ 301 |ITU-T CWDM| 2 | 302 +----------+---------+ 303 |Future use| 3 - 7 | 304 +----------+---------+ 306 (2) C.S.(channel spacing): 4 bits 308 DWDM channel spacing is defined as follows. 310 +----------+---------+ 311 | C.S(GHz) | Value | 312 +----------+---------+ 313 | Reserved | 0 | 314 +----------+---------+ 315 | 100 | 1 | 316 +----------+---------+ 317 | 50 | 2 | 318 +----------+---------+ 319 | 25 | 3 | 320 +----------+---------+ 321 | 12.5 | 4 | 322 +----------+---------+ 323 |Future use| 5 - 15 | 324 +----------+---------+ 326 (3) Identifier: 9 bits 328 The identifier field is a per-node assigned and scoped value. This 329 field MAY change on a per-hop basis. In all cases but one, a node MAY 330 select any value, including zero (0), for this field. Once selected, 331 the value MUST NOT change until the LSP is torn down and the value 332 MUST be used in all LSP related messages, e.g., in Resv messages and 333 label RRO subobjects. The sole special case occurs when this label 334 format is used in a label ERO subobject. In this case, the special 335 value of zero (0) means that the referenced node MAY assign any 336 Identifier field value, including zero (0), when establishing the 337 corresponding LSP. 339 (4) n: 16 bits 341 n is a two's-complement integer to take either a negative, zero or a 342 positive value. The value used to compute the frequency as shown 343 above. 345 3.3. CWDM Wavelength Label 347 For the case of CWDM, the information carried in a Wavelength label 348 is: 350 0 1 2 3 351 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 1 352 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 353 |Grid | C.S | Identifier | n | 354 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 356 The structure of the label in the case of CWDM is the same as that of 357 DWDM case. 359 (1) Grid: 3 bits 361 The value for grid is set to 2 for ITU-T CWDM Grid as defined in 362 [G.694.2]. 364 +----------+---------+ 365 | Grid | Value | 366 +----------+---------+ 367 | Reserved | 0 | 368 +----------+---------+ 369 |ITU-T DWDM| 1 | 370 +----------+---------+ 371 |ITU-T CWDM| 2 | 372 +----------+---------+ 373 |Future use| 3 - 7 | 374 +----------+---------+ 376 (2) C.S.(channel spacing): 4 bits 378 CWDM channel spacing is defined as follows. 380 +----------+---------+ 381 | C.S(nm) | Value | 382 +----------+---------+ 383 | Reserved | 0 | 384 +----------+---------+ 385 | 20 | 1 | 386 +----------+---------+ 387 |Future use| 2 - 15 | 388 +----------+---------+ 390 (3) Identifier: 9 bits 392 The identifier field is a per-node assigned and scoped value. This 393 field MAY change on a per-hop basis. In all cases but one, a node MAY 394 select any value, including zero (0), for this field. Once selected, 395 the value MUST NOT change until the LSP is torn down and the value 396 MUST be used in all LSP related messages, e.g., in Resv messages and 397 label RRO subobjects. The sole special case occurs when this label 398 format is used in a label ERO subobject. In this case, the special 399 value of zero (0) means that the referenced node MAY assign any 400 Identifier field value, including zero (0), when establishing the 401 corresponding LSP. 403 (4) n: 16 bits 405 n is a two's-complement integer. The value used to compute the 406 wavelength as shown above. 408 We do not need to define a new type as the information stored is 409 either a port label or a wavelength label. Only the wavelength label 410 as above needs to be defined. 412 4. Security Considerations 414 This document introduces no new security considerations to [RFC3473]. 415 GMPLS security is described in section 11 of [RFC3471] and refers to 416 [RFC3209] for RSVP-TE. 418 5. IANA Considerations 420 This document has no actions for IANA. 422 6. Acknowledgments 424 The authors would like to thank Adrian Farrel, Lou Berger, Lawrence 425 Mao, Zafar Ali and Daniele Ceccarelli for the discussion and their 426 comments. 428 7. References 430 7.1. Normative References 432 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 433 Requirement Levels", BCP 14, RFC 2119, March 1997. 435 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 436 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 437 Tunnels", RFC 3209, December 2001. 439 [RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching 440 (MPLS) Signaling Functional Description", RFC 3471, January 441 2003. 443 [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching 444 (MPLS) Signaling - Resource ReserVation Protocol Traffic 445 Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. 447 [RFC3945] Mannie, E., Ed., "Generalized Multiprotocol Label Switching 448 (GMPLS) Architecture", RFC 3945, October 2004. 450 7.2. Informative References 452 [G.694.1] ITU-T Recommendation G.694.1, "Spectral grids for WDM 453 applications: DWDM frequency grid", June 2002. 455 [G.694.2] ITU-T Recommendation G.694.2, "Spectral grids for WDM 456 applications: CWDM wavelength grid", December 2003. 458 8. Author's Address 460 Tomohiro Otani 461 KDDI Corporation 462 2-3-2 Nishishinjuku Shinjuku-ku 463 Tokyo, 163-8003, Japan 464 Phone: +81-3-3347-6006 465 Email: tm-otani@kddi.com 467 Richard Rabbat 468 Google, Inc. 469 1600 Amphitheatre Pkwy 470 Mountain View, CA 94043 471 Email: rabbat@alum.mit.edu 473 Sidney Shiba 474 Email: sidney.shiba@yahoo.com 476 Hongxiang Guo 477 Email: hongxiang.guo@gmail.com 479 Keiji Miyazaki 480 Fujitsu Laboratories Ltd 481 4-1-1 Kotanaka Nakahara-ku, 482 Kawasaki Kanagawa, 211-8588, Japan 483 Phone: +81-44-754-2765 484 Email: miyazaki.keiji@jp.fujitsu.com 486 Diego Caviglia 487 Ericsson 488 16153 Genova Cornigliano, ITALY 489 Phone: +390106003736 490 Email: diego.caviglia@ericsson.com 492 Dan Li 493 Huawei Technologies 494 F3-5-B R&D Center, Huawei Base, 495 Shenzhen 518129 China 496 Phone: +86 755-289-70230 497 Email: danli@huawei.com 499 Takehiro Tsuritani 500 KDDI R&D Laboratories Inc. 501 2-1-15 Ohara Fujimino-shi 502 Saitama, 356-8502, Japan 503 Phone: +81-49-278-7806 504 Email: tsuri@kddilabs.jp 506 9. Appendix A. DWDM Example 508 Considering the network displayed in figure 1 it is possible to show 509 an example of LSP set up using the lambda labels. 511 Node 1 receives the request for establishing an LSP from itself to 512 Node 9. The ITU-T grid to be used is the DWDM one, the channel 513 spacing is 50Ghz and the wavelength to be used is 193,35 THz. 515 Node 1 signals the LSP via a Path message including a Wavelength 516 Label structured as defined in section 4.2: 518 0 1 2 3 519 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 1 520 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 521 |Grid | C.S | Identifier | n | 522 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 524 Where: 526 Grid = 1 : ITU-T DWDM grid 528 C.S. = 2 : 50 GHz channel spacing 530 n = 5 : 532 Frequency (THz) = 193.1 THz + n * channel spacing (THz) 534 193.35 (THz) = 193.1 (THz) + n* 0.05 (THz) 536 n = (193.35-193.1)/0.05 = 5 538 10. Appendix B. CWDM Example 540 The network displayed in figure 1 can be used also to display an 541 example of signaling using the Wavelength Label in a CWDM environment. 543 This time the signaling of an LSP from Node 4 to Node 7 is considered. 544 Such LSP exploits the CWDM ITU-T grid with a 20nm channel spacing and 545 is to established using wavelength equal to 1331 nm. 547 Node 4 signals the LSP via a Path message including a Wavelength 548 Label structured as defined in section 4.3: 550 0 1 2 3 551 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 1 552 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 553 |Grid | C.S | Identifier | n | 554 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 556 Where: 558 Grid = 2 : ITU-T CWDM grid 560 C.S. = 1 : 20 nm channel spacing 562 n = -7 : 564 Wavelength (nm) = 1471 nm + n * 20 nm 566 1331 (nm) = 1471 (nm) + n * 20 nm 568 n = (1331-1471)/20 = -7