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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Network Working Group 2 Internet Draft Sharfuddin Syed 3 Intended status: Standard Track Rajan Rao 4 Expires: Oct 23, 2012 Marco Sosa 5 Biao Lu 6 Infinera 8 Bert Basch 9 Andrew G. Malis 10 Verizon Communications 12 April 23, 2012 14 A Framework for control of Flex Grid Networks 15 draft-syed-ccamp-flexgrid-framework-ext-01.txt 17 Abstract 19 This document provides a framework for applying the Generalized 20 Multi-Protocol Label Switching (GMPLS) architecture and protocols to 21 a Flex-Grid capable optical switching layer. 23 Status of this Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF), its areas, and its working groups. Note that 30 other groups may also distribute working documents as Internet- 31 Drafts. 33 Internet-Drafts are draft documents valid for a maximum of six 34 months and may be updated, replaced, or obsoleted by other documents 35 at any time. It is inappropriate to use Internet-Drafts as 36 reference material or to cite them other than as "work in progress." 38 The list of current Internet-Drafts can be accessed at 39 http://www.ietf.org/ietf/1id-abstracts.txt 41 The list of Internet-Draft Shadow Directories can be accessed at 42 http://www.ietf.org/shadow.html 44 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 46 This Internet-Draft will expire on September 23, 2012. 48 Copyright Notice 50 Copyright (c) 2011 IETF Trust and the persons identified as the 51 document authors. All rights reserved. 53 This document is subject to BCP 78 and the IETF Trust's Legal 54 Provisions Relating to IETF Documents 55 (http://trustee.ietf.org/license-info) in effect on the date of 56 publication of this document. Please review these documents 57 carefully, as they describe your rights and restrictions with 58 respect to this document. Code Components extracted from this 59 document must include Simplified BSD License text as described in 60 Section 4.e of the Trust Legal Provisions and are provided without 61 warranty as described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction...................................................2 66 2. Terminology....................................................3 67 3. Acronyms.......................................................4 68 4. Requirements and constraints...................................5 69 5. Use cases......................................................8 70 6. Protocol Implications.........................................14 71 7. Security Considerations.......................................14 72 8. IANA Considerations...........................................14 73 9. References....................................................15 74 9.1. Normative References.....................................15 75 9.2. Informative References...................................15 76 10. Acknowledgments..............................................16 77 11. Authors' Addresses...........................................16 78 12. Contributor's List...........................................17 80 1. Introduction 82 To enable scaling to data rates beyond 100 Gbps, next generation 83 transport systems based on a super-channel concept are currently 84 being developed. To allow efficient allocation of optical spectral 85 bandwidth for such high bit rate systems, the International 86 Telecommunication Union Telecommunication Standardization Sector 87 (ITU-T) is extending the G.694.1 grid standard beyond the 88 traditional fixed grid assignment of a constant spectral width per 89 channel (termed ''Fixed-Grid'') to include flexible grid (termed 91 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 93 ''Flex-Grid'') support allowing for varying spectral width per 94 channel, to support a variety of high-bit rate channels, each 95 optimizing the spectral bandwidth needed for its particular channel 96 type. 98 Current IETF GMPLS efforts for routing and signaling on Wavelength 99 Switched Optical Networks (WSONs) have been focused on Routing and 100 Wavelength Assignment (RWA) for fixed grid Reconfigurable Optical 101 Add-Drop Multiplexors (ROADMs) and line systems. This framework 102 document is intended to set the stage on introducing the flexible 103 grid concept, and setting the requirements and use cases to be taken 104 into consideration for extending the GMPLS protocols to include 105 support for flexible grid capable elements and the need for 106 specifying blocks of spectrum, rather than just wavelengths. 108 Section 2 of this document provides background terminology, while 109 section 3 provides an acronym list. Section 4 then goes over a set 110 of requirements that must be considered when defining the protocol 111 extensions to support flexible grid elements. Section 5 then 112 provides further background with a set of use cases. Section 6 goes 113 over protocol implications; section 7 covers security 114 considerations; section 8 lists IANA considerations. Section 9 115 provides a list of references. Acknowledgements and contact 116 information is provided in sections 10-12. 118 2. Terminology 120 A. Frequency Slot: 121 A frequency range allocated to a given channel and 122 unavailable to other channels within the same flexible grid 123 [FLEX-GRID] 124 It is a contiguous portion of the spectrum available for an 125 optical passband filter. A frequency slot is defined by its 126 nominal central frequency and its slot width. 127 B. Spectral Slice: 128 The minimum granularity of a frequency slot (e.g. 12.5GHz). 129 C. Slot width: 130 The full width of a frequency slot in a flexible grid [FLEX- 131 GRID]. 132 The slot width is equal to number of spectral slices in the 133 slot times the width of spectral slice. 134 D. Super-channel: 136 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 138 A super-channel is a collection of one or more frequency 139 slots to be treated as a unified entity for management and 140 control plane purposes (Ref to figure-1). 141 E. Contiguous Spectrum Super-channel: 142 A contiguous spectrum super-channel is a super-channel with a 143 single frequency slot (Ref to figure-1). 144 F. Split-Spectrum super-channel: 145 A split-Spectrum super-channel is a super-channel with 146 multiple frequency slots. 147 Each frequency slot will be allocated an independent passband 148 filter, irrespective of whether frequency slots are adjacent 149 or not. 151 200 GHz 200 GHz 200 GHz 200 GHz 152 <------> <------> <------> <------> 153 ________ ________ ________ ________ 154 | | | | | | | | 155 | | | | | | | | 156 | | | | | | | | 157 | | | | | | | | 158 |________| |________| |________| |________| 160 |<--s1-->| |<--s2-->| |<--------s3----------->| 162 Contiguous Spectrum super-channels Split Spectrum super-channel 164 Figure 1: Super-Channel 166 3. Acronyms 168 OCG: Optical Carrier Group 170 SCH: Super Channel 172 OCh: Optical Channel 174 OCC: Optical Channel Carrier 176 OTUk: Optical channel Transport Unit level k 178 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 180 ODUk: Optical channel Data Unit Level k 182 ODUj: Optical channel Data Unit Level j 184 CDC: Colorless, Directionless and Contentionless 186 CD: Colorless and Directionless 188 ROADM: Reconfigurable Optical Add-Drop Multiplexer 190 4. Requirements and constraints 192 This section covers the high level requirements for the support of 193 super-channels over flexible grid infrastructure (Flex-Grid). 194 Specifically, the scope of requirements and constraints listed in 195 this section covers the functionality that shall be supported by the 196 control plane sub-system. The Features are listed as a list of 197 Requirements Tagged as Rn, for better traceability and coverage in 198 other related drafts and/or for references by other related 199 standards across other standard bodies. 201 R1: Flexible size of super-channel 203 The protocol shall allow the super-channels on the Flex-Grid to be 204 of different size/width. The number of slices and the granularity of 205 each slice shall be flexible. 207 R2: Flexible mapping of super-channel 209 The super-channels shall be allowed to be mapped to any spectrum 210 location in the ITU Grid. 212 The frequency slots allocation of super-channels on the ITU-Grid 213 shall confirm to [FLEX-GRID] 215 R3: Contiguous Spectrum and Split Spectrum super-channel 217 The protocol shall allow the use of super-channels which can be 218 contiguous or non-contiguous. 220 Example: consider a system supporting 500GHz super-channel. 222 In case of contiguous spectrum, the super-channel is allocated with 223 40 slices of 12.5GHz granularity. This super-channel is placed 224 directly on the Flex-Grid at any location. 226 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 228 In case of split spectrum, the super-channel is divided into 229 multiple members. Considering the same example scenario, the 500GHz 230 super-channel can be divided into 2 member split spectrum channels. 231 Each member is allocated a different flexible location on the Flex- 232 Grid. Each frequency slot can be 250GHz, 20x12.5GHz slices allocated 233 for frequency slot. 235 R4: Co-routing of split-spectrum super-channel 237 The protocol shall support the co-routing of frequency slots 238 within the split-spectrum super-channels. 240 Please refer to the Figure 5 and Use Case 3, depicting the co- 241 routing of split-spectrum super-channels. 243 R5: Flexible Modulation Formats and polarization mode for different 244 super-channels on the same Flex-Grid 246 Each super-channel mapped on to the Flex-Grid system shall have the 247 capability to support different modulation formats with either 248 single or dual polarization modes. 250 R6: Fixed vs Flexible Grid super-channel interworking 252 The Control Plane protocol shall handle nodes which support flex- 253 grid functionality in addition to nodes that only support fixed grid 254 functionality. The enhanced control plane protocol with the flex- 255 grid extensions shall also be able to work with fixed grid network 256 in a backwards compatible manner. 258 This requirement is to enable introduction of flex-grid systems into 259 existing fixed-grid network. This can also be used to deploy flex- 260 grid system in certain segments of the network. Please also refer to 261 the use case section of this document. 263 R7: Support for the CDC based super-channels over Flex-Grid 265 The super-channel over the Flex-Grid control plane frame work shall 266 support CDC (Connectionless, Directionless and Contentionless) 267 architecture. Further, flexibility of control shall be provided, 268 such that, depending on deployment scenarios and application, a sub- 269 set of CDC features are used on a given network segment. Hence, each 270 type of ROADMs shall be supported. 272 R8: Directionless/Contentionless super-channels 274 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 276 The protocol shall allow for routing the super-channels in different 277 fiber directions/degrees, based on the following criteria: 279 a) Based on spectral slices 280 b) Based on fibers/nodes 282 The super-channels with the same frequency slot mapping are not 283 allowed to be provisioned over a given fiber direction. 285 Please refer to the Figure 5 and Use Case 3, depicting the handling 286 of same super-channel at a CDC node. 288 R9: Resizing of super-channel bandwidth 290 Depending on the spectral bandwidth changes, the protocol shall 291 allow super-channels resizing. 293 R10: super-channel LSP restoration 295 The protocol shall support the super-channel based LSP restoration 296 feature, with the following features: 298 a) During the restoration process, it shall be possible for the 299 protocol to pick different frequency slots of super-channel, 300 keeping the number and size of slices the same. 301 b) LSP restoration with optional pre-computed path (with or without 302 resource reservation) shall be supported. 303 c) Revertive and Non-Revertive restoration options shall be provided. 305 R11: Embedded Control Channel for super-channel routing and 306 signaling 308 The system shall continue to use the standard mechanism for ECC 309 defined in [ref: OSC based control channel], for OAM features 310 required to be supported between network elements deploying super- 311 channel over Flex-Grid. 313 R12: Management Plane and Control Plane feature interaction for 314 super-channel 316 The system shall keep track of important bandwidth related 317 parameters for the Flex-Grid based system. Important parameters 318 include (but not limited to): 320 a) Available Spectral Slices 321 b) Provisioned super-channels along with provisioned spectral-slices 323 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 325 5. Use cases 327 The use cases described in this section are for information only. 328 The OTN hierarchy described in this section is sure to be discussed 329 in ITU SG-15 Q6 & Q14. Within the scope of this frame-work document, 330 the main focus is super-channel entity. The remaining layers are 331 described to illustrate the relationship with the digital layers. 333 With respect to the mapping hierarchy in the OTN layers, multiple 334 OCHs are mapped to the SCH, and multiple OCCs (Optical Channel 335 Carriers) are mapped to an OCH. This hierarchy is depicted in Figure 336 2 below. Specifically, the following flexibility of number of 337 instances that are mapped between the layers shall be supported. 339 X number of OCC mapped to OCH 341 Y number of OCH mapped to SCH 343 Z number of SCH mapped to OCG 345 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 347 __________ __________ 348 | | | | 349 | ODUj | ... | ODUj | 350 |__________| |__________| 351 | | 352 | | 353 ____|__________________|____ 354 | | 355 | OTUk | 356 |____________________________| 357 | 358 | 359 _____________|______________ 360 | | 361 | OCH | 362 |____________________________| 363 | | 364 | | 365 ____|_____ _____|____ 366 | | | | 367 |carrier 1 | ... |carrier n | 368 |__________| |__________| 369 | | 370 | | 371 ____|__________________|____ 372 | | 373 | SCH | 374 |____________________________| 375 | 376 | 377 ______________|_____________ 378 | | 379 | SCG | 380 |____________________________| 381 Figure 2: Super-Channel mapping to OTN hierarchy 383 Example Use Case 1: Super-Channel with multiple OCHs and multiple 384 carriers per OCHs. 386 The following Figure 3 gives an example use case where multiple OCH 387 are carrier over a single SCH. Please note that this is an example 388 use case only. In general, the system shall be capable of supporting 389 flexible mapping where there is flexible number of carriers mapped 390 into an OCH and a flexible number of OCHs mapped to a single Super- 391 Channel. 393 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 395 ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ 396 | | | || | | || | | || | | || | | | 397 |ODUj|..|ODUj||ODUj|..|ODUj||ODUj|..|ODUj||ODUj|..|ODUj||ODUj|..|ODUj| 398 |____| |____||____| |____||____| |____||____| |____||____| |____| 399 | | | | | | | | | | 400 | | | | | | | | | | 401 _|______|___ _|______|___ _|______|___ _|______|___ _|_______|__ 402 | || || || || | 403 | OTUk || OTUk || OTUk || OTUk || OTUk | 404 |____________||____________||____________||____________||____________| 405 | | | | | 406 | | | | | 407 _____|_______ _____|______ _____|______ _____|______ _____|______ 408 | || || || || | 409 | OCH || OCH || OCH || OCH || OCH | 410 |____________||____________||____________||____________||____________| 411 | | | | | | | | | | 412 | | | | | | | | | | 413 _|__ _|__ _|__ _|__ _|__ _|__ _|__ _|__ _|__ _|__ 414 | | | | | | | | | | | | | | | | | | | | 415 | C1 | | C2 | | C3 | | C4 | | C5 | | C6 | | C7 | | C8 | | C9 | |C10 | 416 |____| |____| |____| |____| |____| |____| |____| |____| |____| |____| 417 | | | | | | | | | | 418 | | | | | | | | | | 419 _|______|______|______|______|______|______|______|______|______|___ 420 | | 421 | SCH | 422 |____________________________________________________________________| 423 | 424 | 425 ______________|_____________ 426 | | 427 | OCG | 428 |____________________________| 429 Figure 3: Super-Channel use case showing multiple OCH and multiple carriers per OCH 430 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 432 Example Use Case 2: 434 The following Figure 4 shows the case where multiple OCHs are 435 carried over separate super-channels. 437 ____ ____ ____ ____ 438 | | | | | | | | 439 |ODUj|.. |ODUj| |ODUj|.. |ODUj| 440 |____| |____| |____| |____| 441 | | | | 442 | | | | 443 ___|________________________|____ __|_________________________|____ 444 | | | | 445 | OTUk | | OTUk | 446 |_________________________________| |_________________________________| 447 | | 448 | | 449 ________________|________________ ________________|________________ 450 | | | | 451 | OCH | | OCH | 452 |_________________________________| |_________________________________| 453 | | | | | | | | | | 454 | | | | | | | | | | 455 __|__ _|__ _|__ _|__ _|__ _|__ _|__ _|__ _|__ _|__ 456 | | | | | | | | | | | | | | | | | | | | 457 | C1 | | C2 | | C3 | | C4 | | C5 | | C6 | | C7 | | C8 | | C9 | |C10 | 458 |____| |____| |____| |____| |____| |____| |____| |____| |____| |____| 459 | | | | | | | | | | 460 | | | | | | | | | | 461 __|______|______|______|______|_ _|______|______|______|______|__ 462 | | | | 463 | SCH1 | | SCH2 | 464 |________________________________| |________________________________| 465 \ / 466 \ / 467 \____________________________________/ 468 | 469 ______________|_____________ 470 | | 471 | SCG | 472 |____________________________| 473 Figure 4: Split-Spectrum Super-Channel use case showing multiple OCH and multiple 474 carriers per OCH 475 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 477 Example Use Case 3: Network Level Use Case of super-channel 479 A network level diagram to illustrate the use of CDC based super- 480 channel (contiguous spectrum and split-spectrum) is shown in Figure 481 5 below. In this scenario, N1 and N2 are digital/TDM nodes, where 482 the client services originate. N2, N3, N4 and N5 are Optical/WDM 483 nodes on which the super-channels are provisioned. Node N2 is CDC 484 ROADM and Nodes N3, N4 and N5 are Colorless ROADMs only. 486 Four super-channels are provisioned in this example network. Super- 487 Channels S1 are contiguous spectrum super-channels, both using the 488 same frequency slots, and are added/dropped at Node N2. The 489 contention for the same super-channel (with exactly the same 490 frequency slot mapping) is avoided by routing these super-channels 491 in different degrees of the network. Alternatively, if these super- 492 channels have to go through the same fiber path, then the frequency 493 slots occupied on the Flex-Grid shall be different. 495 Super-channels S2-1 and S2-2 illustrates the split-spectrum super- 496 channel that is co-routed over the same fibers in the network. 498 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 500 | 501 | 502 --------- 503 | | 504 | N4 | 505 | | 506 | | 507 --------- 508 / \ 510 S1, s2-1, s2-2 / \ s2-1, s2-2 512 _________ _________ / D1 \_________ ______ 513 | |--s1----| | | | | | 514 | |--s2-1--| | | N5 |--s2-1-| N6 | 515 | N1 |--s2-2--| N2 | | |--s2-1-| | 516 _ |_________|--s1--- |_________| |_________| |______| 517 \ D2 / 519 S1 \ / 521 \ / 523 _________ 524 | | 525 | N3 | 526 | | 527 |_________| 528 | 529 | 530 | s1 531 Figure 5: Super-Channel Network Level use case 533 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 535 Example Use Case 4: Fixed and Flexible Grid Interworking 537 - In Figure 6: 538 o The Nodes N2 and N3 are Flex-Grid and Fixed grid capable 539 nodes 540 o The Nodes N1 and N4 are fixed grid capable nodes. 541 - Fixed and Flexible support on the same interface 542 o In Figure 6, this is represented by Link L3 543 - BW advertisement that include both fixed and flexible grid by Flex 544 Grid capable nodes 545 - Signaling support for both fixed and flex-grid. 547 ________ _________ ________ ________ 548 | |--L1--| | | | | | 549 | | | |---L3--- | |---L4----| | 550 | |--L2--| | | | | | 551 |________| |_________| |________| |________| 553 Figure 6: Use case for fixed and flex-grid interworking 555 6. Protocol Implications 557 Support GMPLS Routing extensions to satisfy requirements in section 558 4.0. 560 Support GMPLS Signaling extensions to satisfy requirements in 561 section 4.0. 563 7. Security Considerations 565 567 8. IANA Considerations 569 IANA needs to assign a new Grid field value to represent ITU-T Flex- 570 Grid. 572 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 574 9. References 576 9.1. Normative References 578 [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate 579 Requirement Levels", BCP 14, RFC 2119, March 1997. 581 9.2. Informative References 583 [1] ITU-T Recommendation G.694.1, "Spectral grids for WDM 584 applications: DWDM frequency grid", June 2002 586 [2] [FLEX-GRID] Unpublished ITU-T Study Group-15 doc: G.694.1 587 [Rev-2, 12/2011] 589 [3] [RFC 6163] Framework for GMPLS and Path Computation Element 590 (PCE) Control of Wavelength Switched Optical Networks (WSONs) 592 [4] draft-ietf-ccamp-rwa-info-13.txt: Routing and Wavelength 593 Assignment Information Model for Wavelength Switched Optical 594 Networks 596 [5] draft-syed-ccamp-flexgrid-framework-ext.pdf - - PDF version of 597 this draft which contains figures. 599 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 601 10. Acknowledgments 603 11. Authors' Addresses 605 Sharfuddin Syed 606 Infinera 607 140 Caspian Ct., Sunnyvale, CA 94089 608 Email: ssyed@infinera.com 610 Rajan Rao 611 Infinera 612 140 Caspian Ct., Sunnyvale, CA 94089 613 Email: rrao@infinera.com 615 Marco Sosa 616 Infinera 617 140 Caspian Ct., Sunnyvale, CA 94089 618 Email: msosa@infinera.com 620 Biao Lu 621 Infinera 622 140 Caspian Ct., Sunnyvale, CA 94089 623 Email: blu@infinera.com 625 Bert Basch 626 Verizon Communications 627 60 Sylvan Rd., Waltham, MA 02451 628 Email: bert.e.basch@verizon.com 630 Andrew G. Malis 631 Verizon Communications 632 60 Sylvan Rd., Waltham, MA 02451 633 Email: andrew.g.malis@verizon.com 635 Internet-Draft draft-syed-ccamp-flexgrid-framework-ext Apr-23 637 12. Contributor's List 639 Radhakrishna Valiveti 640 Email: rvaliveti@infinera.com 642 Iftekhar Hussain 643 Email: IHussain@infinera.com 645 Abinder Dhillon 646 Email: ADhillon@infinera.com 648 Mike VanLeeuwen 649 Email: MVanleeuwen@infinera.com 651 Ping Pan 652 Email: ppan@infinera.com