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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Network Working Group Y. Lee 2 Internet Draft Huawei 3 Intended status: Informational G. Bernstein 4 Expires: April 2012 Grotto Networking 5 D. Li 6 Huawei 7 W. Imajuku 8 NTT 10 October 31, 2011 12 Routing and Wavelength Assignment Information Model for Wavelength 13 Switched Optical Networks 15 draft-ietf-ccamp-rwa-info-13.txt 17 Status of this Memo 19 This Internet-Draft is submitted to IETF in full conformance with 20 the provisions of BCP 78 and BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF), its areas, and its working groups. Note that 24 other groups may also distribute working documents as Internet- 25 Drafts. 27 Internet-Drafts are draft documents valid for a maximum of six 28 months and may be updated, replaced, or obsoleted by other documents 29 at any time. It is inappropriate to use Internet-Drafts as 30 reference material or to cite them other than as "work in progress." 32 The list of current Internet-Drafts can be accessed at 33 http://www.ietf.org/ietf/1id-abstracts.txt 35 The list of Internet-Draft Shadow Directories can be accessed at 36 http://www.ietf.org/shadow.html 38 This Internet-Draft will expire on March 31, 2012. 40 Copyright Notice 42 Copyright (c) 2011 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (http://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with 50 respect to this document. Code Components extracted from this 51 document must include Simplified BSD License text as described in 52 Section 4.e of the Trust Legal Provisions and are provided without 53 warranty as described in the Simplified BSD License. 55 Abstract 57 This document provides a model of information needed by the routing 58 and wavelength assignment (RWA) process in wavelength switched 59 optical networks (WSONs). The purpose of the information described 60 in this model is to facilitate constrained lightpath computation in 61 WSONs. This model takes into account compatibility constraints 62 between WSON signal attributes and network elements but does not 63 include constraints due to optical impairments. Aspects of this 64 information that may be of use to other technologies utilizing a 65 GMPLS control plane are discussed. 67 Table of Contents 69 1. Introduction...................................................3 70 1.1. Revision History..........................................4 71 1.1.1. Changes from 01......................................4 72 1.1.2. Changes from 02......................................4 73 1.1.3. Changes from 03......................................5 74 1.1.4. Changes from 04......................................5 75 1.1.5. Changes from 05......................................5 76 1.1.6. Changes from 06......................................5 77 1.1.7. Changes from 07......................................5 78 1.1.8. Changes from 08......................................5 79 1.1.9. Changes from 09......................................5 80 1.1.10. Changes from 10.....................................6 81 1.1.11. Changes from 11.....................................6 82 1.1.12. Changes from 12.....................................6 83 2. Terminology....................................................6 84 3. Routing and Wavelength Assignment Information Model............7 85 3.1. Dynamic and Relatively Static Information.................7 86 4. Node Information (General).....................................8 87 4.1. Connectivity Matrix.......................................8 88 4.2. Shared Risk Node Group....................................9 89 5. Node Information (WSON specific)...............................9 90 5.1. Resource Accessibility/Availability......................10 91 5.2. Resource Signal Constraints and Processing Capabilities..14 92 5.3. Compatibility and Capability Details.....................15 93 5.3.1. Shared Input or Output Indication...................15 94 5.3.2. Modulation Type List................................15 95 5.3.3. FEC Type List.......................................15 96 5.3.4. Bit Rate Range List.................................15 97 5.3.5. Acceptable Client Signal List.......................16 98 5.3.6. Processing Capability List..........................16 99 6. Link Information (General)....................................16 100 6.1. Administrative Group.....................................17 101 6.2. Interface Switching Capability Descriptor................17 102 6.3. Link Protection Type (for this link).....................17 103 6.4. Shared Risk Link Group Information.......................17 104 6.5. Traffic Engineering Metric...............................17 105 6.6. Port Label (Wavelength) Restrictions.....................18 106 6.6.1. Port-Wavelength Exclusivity Example.................19 107 7. Dynamic Components of the Information Model...................21 108 7.1. Dynamic Link Information (General).......................21 109 7.2. Dynamic Node Information (WSON Specific).................21 110 8. Security Considerations.......................................21 111 9. IANA Considerations...........................................22 112 10. Acknowledgments..............................................22 113 11. References...................................................23 114 11.1. Normative References....................................23 115 11.2. Informative References..................................24 116 12. Contributors.................................................25 117 Author's Addresses...............................................26 118 Intellectual Property Statement..................................26 119 Disclaimer of Validity...........................................27 121 1. Introduction 123 The purpose of the following information model for WSONs is to 124 facilitate constrained lightpath computation and as such is not a 125 general purpose network management information model. This 126 constraint is frequently referred to as the "wavelength continuity" 127 constraint, and the corresponding constrained lightpath computation 128 is known as the routing and wavelength assignment (RWA) problem. 129 Hence the information model must provide sufficient topology and 130 wavelength restriction and availability information to support this 131 computation. More details on the RWA process and WSON subsystems and 132 their properties can be found in [RFC6163]. The model defined here 133 includes constraints between WSON signal attributes and network 134 elements, but does not include optical impairments. 136 In addition to presenting an information model suitable for path 137 computation in WSON, this document also highlights model aspects 138 that may have general applicability to other technologies utilizing 139 a GMPLS control plane. The portion of the information model 140 applicable to other technologies beyond WSON is referred to as 141 "general" to distinguish it from the "WSON-specific" portion that is 142 applicable only to WSON technology. 144 1.1. Revision History 146 1.1.1. Changes from 01 148 Added text on multiple fixed and switched connectivity matrices. 150 Added text on the relationship between SRNG and SRLG and encoding 151 considerations. 153 Added clarifying text on the meaning and use of port/wavelength 154 restrictions. 156 Added clarifying text on wavelength availability information and how 157 to derive wavelengths currently in use. 159 1.1.2. Changes from 02 161 Integrated switched and fixed connectivity matrices into a single 162 "connectivity matrix" model. Added numbering of matrices to allow 163 for wavelength (time slot, label) dependence of the connectivity. 164 Discussed general use of this node parameter beyond WSON. 166 Integrated switched and fixed port wavelength restrictions into a 167 single port wavelength restriction of which there can be more than 168 one and added a reference to the corresponding connectivity matrix 169 if there is one. Also took into account port wavelength restrictions 170 in the case of symmetric switches, developed a uniform model and 171 specified how general label restrictions could be taken into account 172 with this model. 174 Removed the Shared Risk Node Group parameter from the node info, but 175 left explanation of how the same functionality can be achieved with 176 existing GMPLS SRLG constructs. 178 Removed Maximum bandwidth per channel parameter from link 179 information. 181 1.1.3. Changes from 03 183 Removed signal related text from section 3.2.4 as signal related 184 information is deferred to a new signal compatibility draft. 186 Removed encoding specific text from Section 3.3.1 of version 03. 188 1.1.4. Changes from 04 190 Removed encoding specific text from Section 4.1. 192 Removed encoding specific text from Section 3.4. 194 1.1.5. Changes from 05 196 Renumbered sections for clarity. 198 Updated abstract and introduction to encompass signal 199 compatibility/generalization. 201 Generalized Section on wavelength converter pools to include electro 202 optical subsystems in general. This is where signal compatibility 203 modeling was added. 205 1.1.6. Changes from 06 207 Simplified information model for WSON specifics, by combining 208 similar fields and introducing simpler aggregate information 209 elements. 211 1.1.7. Changes from 07 213 Added shared fiber connectivity to resource pool modeling. This 214 includes information for determining wavelength collision on an 215 internal fiber providing access to resource blocks. 217 1.1.8. Changes from 08 219 Added PORT_WAVELENGTH_EXCLUSIVITY in the RestrictionType parameter. 220 Added section 6.6.1 that has an example of the port wavelength 221 exclusivity constraint. 223 1.1.9. Changes from 09 225 Section 5: clarified the way that the resource pool is modeled from 226 blocks of identical resources. 228 Section 5.1: grammar fixes. Removed reference to "academic" modeling 229 pre-print. Clarified RBNF resource pool model details. 231 Section 5.2: Formatting fixes. 233 1.1.10. Changes from 10 235 Enhanced the explanation of shared fiber access to resources and 236 updated Figure 2 to show a more general situation to be modeled. 238 Removed all 1st person idioms. 240 1.1.11. Changes from 11 242 Replace all instances of "ingress" with "input" and all instances of 243 "egress" with "output". Added clarifying text on relationship 244 between resource block model and physical entities such as line 245 cards. 247 1.1.12. Changes from 12 249 Section 5.2: Clarified RBNF optional elements for several 250 definitions. 252 Section 5.3.6: Clarified RBNF optional elements for 253 . 255 Editorial changes for clarity. 257 Update the contributor list. 259 2. Terminology 261 CWDM: Coarse Wavelength Division Multiplexing. 263 DWDM: Dense Wavelength Division Multiplexing. 265 FOADM: Fixed Optical Add/Drop Multiplexer. 267 ROADM: Reconfigurable Optical Add/Drop Multiplexer. A reduced port 268 count wavelength selective switching element featuring input and 269 output line side ports as well as add/drop side ports. 271 RWA: Routing and Wavelength Assignment. 273 Wavelength Conversion. The process of converting an information 274 bearing optical signal centered at a given wavelength to one with 275 "equivalent" content centered at a different wavelength. Wavelength 276 conversion can be implemented via an optical-electronic-optical 277 (OEO) process or via a strictly optical process. 279 WDM: Wavelength Division Multiplexing. 281 Wavelength Switched Optical Network (WSON): A WDM based optical 282 network in which switching is performed selectively based on the 283 center wavelength of an optical signal. 285 3. Routing and Wavelength Assignment Information Model 287 The following WSON RWA information model is grouped into four 288 categories regardless of whether they stem from a switching 289 subsystem or from a line subsystem: 291 o Node Information 293 o Link Information 295 o Dynamic Node Information 297 o Dynamic Link Information 299 Note that this is roughly the categorization used in [G.7715] 300 section 7. 302 In the following, where applicable, the reduced Backus-Naur form 303 (RBNF) syntax of [RBNF] is used to aid in defining the RWA 304 information model. 306 3.1. Dynamic and Relatively Static Information 308 All the RWA information of concern in a WSON network is subject to 309 change over time. Equipment can be upgraded; links may be placed in 310 or out of service and the like. However, from the point of view of 311 RWA computations there is a difference between information that can 312 change with each successive connection establishment in the network 313 and that information that is relatively static on the time scales of 314 connection establishment. A key example of the former is link 315 wavelength usage since this can change with connection 316 setup/teardown and this information is a key input to the RWA 317 process. Examples of relatively static information are the 318 potential port connectivity of a WDM ROADM, and the channel spacing 319 on a WDM link. 321 This document separates, where possible, dynamic and static 322 information so that these can be kept separate in possible encodings 323 and hence allowing for separate updates of these two types of 324 information thereby reducing processing and traffic load caused by 325 the timely distribution of the more dynamic RWA WSON information. 327 4. Node Information (General) 329 The node information described here contains the relatively static 330 information related to a WSON node. This includes connectivity 331 constraints amongst ports and wavelengths since WSON switches can 332 exhibit asymmetric switching properties. Additional information 333 could include properties of wavelength converters in the node if any 334 are present. In [Switch] it was shown that the wavelength 335 connectivity constraints for a large class of practical WSON devices 336 can be modeled via switched and fixed connectivity matrices along 337 with corresponding switched and fixed port constraints. These 338 connectivity matrices are included with the node information while 339 the switched and fixed port wavelength constraints are included with 340 the link information. 342 Formally, 344 ::= [...] 346 Where the Node_ID would be an appropriate identifier for the node 347 within the WSON RWA context. 349 Note that multiple connectivity matrices are allowed and hence can 350 fully support the most general cases enumerated in [Switch]. 352 4.1. Connectivity Matrix 354 The connectivity matrix (ConnectivityMatrix) represents either the 355 potential connectivity matrix for asymmetric switches (e.g. ROADMs 356 and such) or fixed connectivity for an asymmetric device such as a 357 multiplexer. Note that this matrix does not represent any particular 358 internal blocking behavior but indicates which inputinput ports and 359 wavelengths could possibly be connected to a particular output port. 360 Representing internal state dependent blocking for a switch or ROADM 361 is beyond the scope of this document and due to its highly 362 implementation dependent nature would most likely not be subject to 363 standardization in the future. The connectivity matrix is a 364 conceptual M by N matrix representing the potential switched or 365 fixed connectivity, where M represents the number of inputinput 366 ports and N the number of outputoutput ports. This is a "conceptual" 367 matrix since the matrix tends to exhibit structure that allows for 368 very compact representations that are useful for both transmission 369 and path computation [Encode]. 371 Note that the connectivity matrix information element can be useful 372 in any technology context where asymmetric switches are utilized. 374 ConnectivityMatrix ::= 376 Where 378 is a unique identifier for the matrix. 380 can be either 0 or 1 depending upon whether the 381 connectivity is either fixed or potentially switched. 383 represents the fixed or switched connectivity in that 384 Matrix(i, j) = 0 or 1 depending on whether inputinput port i can 385 connect to outputoutput port j for one or more wavelengths. 387 4.2. Shared Risk Node Group 389 SRNG: Shared risk group for nodes. The concept of a shared risk link 390 group was defined in [RFC4202]. This can be used to achieve a 391 desired "amount" of link diversity. It is also desirable to have a 392 similar capability to achieve various degrees of node diversity. 393 This is explained in [G.7715]. Typical risk groupings for nodes can 394 include those nodes in the same building, within the same city, or 395 geographic region. 397 Since the failure of a node implies the failure of all links 398 associated with that node a sufficiently general shared risk link 399 group (SRLG) encoding, such as that used in GMPLS routing extensions 400 can explicitly incorporate SRNG information. 402 5. Node Information (WSON specific) 404 As discussed in [RFC6163] a WSON node may contain electro-optical 405 subsystems such as regenerators, wavelength converters or entire 406 switching subsystems. The model present here can be used in 407 characterizing the accessibility and availability of limited 408 resources such as regenerators or wavelength converters as well as 409 WSON signal attribute constraints of electro-optical subsystems. As 410 such this information element is fairly specific to WSON 411 technologies. 413 A WSON node may include regenerators or wavelength converters 414 arranged in a shared pool. As discussed in [RFC6163] this can 415 include OEO based WDM switches as well. There are a number of 416 different approaches used in the design of WDM switches containing 417 regenerator or converter pools. However, from the point of view of 418 path computation the following need to be known: 420 1. The nodes that support regeneration or wavelength conversion. 422 2. The accessibility and availability of a wavelength converter to 423 convert from a given inputinput wavelength on a particular 424 inputinput port to a desired outputoutput wavelength on a 425 particular outputoutput port. 427 3. Limitations on the types of signals that can be converted and the 428 conversions that can be performed. 430 Since resources tend to be packaged together in blocks of similar 431 devices, e.g., on line cards or other types of modules, the 432 fundamental unit of identifiable resource in this document is the 433 "resource block". A resource block may contain one or more 434 resources. As resources are the smallest identifiable unit of 435 processing resource, one can group together resources into blocks if 436 they have similar characteristics relevant to the optical system 437 being modeled, e.g., processing properties, accessibility, etc. 439 This leads to the following formal high level model: 441 ::= [...] 442 [] 444 Where 446 ::= ... 447 [...] [...] 448 [] 450 First the accessibility of resource blocks is addressed then their 451 properties are discussed. 453 5.1. Resource Accessibility/Availability 455 A similar technique as used to model ROADMs and optical switches can 456 be used to model regenerator/converter accessibility. This technique 457 was generally discussed in [RFC6163] and consisted of a matrix to 458 indicate possible connectivity along with wavelength constraints for 459 links/ports. Since regenerators or wavelength converters may be 460 considered a scarce resource it is desirable that the model include, 461 if desired, the usage state (availability) of individual 462 regenerators or converters in the pool. Models that incorporate more 463 state to further reveal blocking conditions on input or output to 464 particular converters are for further study and not included here. 466 The three stage model is shown schematically in Figure 1 and Figure 467 2. The difference between the two figures is that Figure 1 assumes 468 that each signal that can get to a resource block may do so, while 469 in Figure 2 the access to sets of resource blocks is via a shared 470 fiber which imposes its own wavelength collision constraint. The 471 representation of Figure 1 can have more than one input to each 472 resource block since each input represents a single wavelength 473 signal, while in Figure 2 shows a single multiplexed WDM inputinput 474 or output, e.g., a fiber, to/from each set of block. 476 This model assumes N input ports (fibers), P resource blocks 477 containing one or more identical resources (e.g. wavelength 478 converters), and M output ports (fibers). Since not all input ports 479 can necessarily reach each resource block, the model starts with a 480 resource pool input matrix RI(i,p) = {0,1} whether input port i can 481 reach potentially reach resource block p. 483 Since not all wavelengths can necessarily reach all the resources or 484 the resources may have limited input wavelength range the model has 485 a set of relatively static input port constraints for each resource. 486 In addition, if the access to a set of resource blocks is via a 487 shared fiber (Figure 2) this would impose a dynamic wavelength 488 availability constraint on that shared fiber. The resource block 489 input port constraint is modeled via a static wavelength set 490 mechanism and the case of shared access to a set of blocks is 491 modeled via a dynamic wavelength set mechanism. 493 Next a state vector RA(j) = {0,...,k} is used to track the number of 494 resources in resource block j in use. This is the only state kept in 495 the resource pool model. This state is not necessary for modeling 496 "fixed" transponder system or full OEO switches with WDM interfaces, 497 i.e., systems where there is no sharing. 499 After that, a set of static resource output wavelength constraints 500 and possibly dynamic shared output fiber constraints maybe used. The 501 static constraints indicate what wavelengths a particular resource 502 block can generate or are restricted to generating e.g., a fixed 503 regenerator would be limited to a single lambda. The dynamic 504 constraints would be used in the case where a single shared fiber is 505 used to output the resource block (Figure 2). 507 Finally, to complete the model, a resource pool output matrix 508 RE(p,k) = {0,1} depending on whether the output from resource block 509 p can reach output port k, may be used. 511 I1 +-------------+ +-------------+ E1 512 ----->| | +--------+ | |-----> 513 I2 | +------+ Rb #1 +-------+ | E2 514 ----->| | +--------+ | |-----> 515 | | | | 516 | Resource | +--------+ | Resource | 517 | Pool +------+ +-------+ Pool | 518 | | + Rb #2 + | | 519 | Input +------+ +-------| Output | 520 | Connection | +--------+ | Connection | 521 | Matrix | . | Matrix | 522 | | . | | 523 | | . | | 524 IN | | +--------+ | | EM 525 ----->| +------+ Rb #P +-------+ |-----> 526 | | +--------+ | | 527 +-------------+ ^ ^ +-------------+ 528 | | 529 | | 530 | | 531 | | 533 Input wavelength Output wavelength 534 constraints for constraints for 535 each resource each resource 537 Figure 1 Schematic diagram of resource pool model. 539 I1 +-------------+ +-------------+ E1 540 ----->| | +--------+ | |-----> 541 I2 | +======+ Rb #1 +-+ + | E2 542 ----->| | +--------+ | | |-----> 543 | | |=====| | 544 | Resource | +--------+ | | Resource | 545 | Pool | +-+ Rb #2 +-+ | Pool | 546 | | | +--------+ + | 547 | Input |====| | Output | 548 | Connection | | +--------+ | Connection | 549 | Matrix | +-| Rb #3 |=======| Matrix | 550 | | +--------+ | | 551 | | . | | 552 | | . | | 553 | | . | | 554 IN | | +--------+ | | EM 555 ----->| +======+ Rb #P +=======+ |-----> 556 | | +--------+ | | 557 +-------------+ ^ ^ +-------------+ 558 | | 559 | | 560 | | 561 Single (shared) fibers for block input and output 563 Input wavelength Output wavelength 564 availability for availability for 565 each block input fiber each block output fiber 567 Figure 2 Schematic diagram of resource pool model with shared block 568 accessibility. 570 Formally the model can be specified as: 572 574 ::= 575 577 578 ::=()... 581 Note that except for all the other components of 582 are relatively static. Also the 583 and are only used 584 in the cases of shared input or output access to the particular 585 block. See the resource block information in the next section to see 586 how this is specified. 588 5.2. Resource Signal Constraints and Processing Capabilities 590 The wavelength conversion abilities of a resource (e.g. regenerator, 591 wavelength converter) were modeled in the 592 previously discussed. As discussed in [RFC6163] the constraints on 593 an electro-optical resource can be modeled in terms of input 594 constraints, processing capabilities, and output constraints: 596 ::= ([] 597 [] )* 599 Where is a list of resource block identifiers with 600 the same characteristics. If this set is missing the constraints are 601 applied to the entire network element. 603 The are signal compatibility based constraints 604 and/or shared access constraint indication. The details of these 605 constraints are defined in section 5.3. 607 ::= [] 608 [] [] [] 610 The are important operations that the 611 resource (or network element) can perform on the signal. The details 612 of these capabilities are defined in section 5.3. 614 ::= [] 615 [] [] [] 617 The are either restrictions on the properties of 618 the signal leaving the block, options concerning the signal 619 properties when leaving the resource or shared fiber output 620 constraint indication. 622 := [] 623 [] 624 5.3. Compatibility and Capability Details 626 5.3.1. Shared Input or Output Indication 628 As discussed in the previous section and shown in Figure 2 the input 629 or output access to a resource block may be via a shared fiber. The 630 and elements are indicators for this 631 condition with respect to the block being described. 633 5.3.2. Modulation Type List 635 Modulation type, also known as optical tributary signal class, 636 comes in two distinct flavors: (i) ITU-T standardized types; (ii) 637 vendor specific types. The permitted modulation type list can 638 include any mixture of standardized and vendor specific types. 640 ::= 641 [|]... 643 Where the STANDARD_MODULATION object just represents one of the 644 ITU-T standardized optical tributary signal class and the 645 VENDOR_MODULATION object identifies one vendor specific 646 modulation type. 648 5.3.3. FEC Type List 650 Some devices can handle more than one FEC type and hence a list 651 is needed. 653 ::= [] 655 Where the FEC object represents one of the ITU-T standardized 656 FECs defined in [G.709], [G.707], [G.975.1] or a vendor-specific 657 FEC. 659 5.3.4. Bit Rate Range List 661 Some devices can handle more than one particular bit rate range 662 and hence a list is needed. 664 ::= []... 666 ::= 668 Where the START_RATE object represents the lower end of the range 669 and the END_RATE object represents the higher end of the range. 671 5.3.5. Acceptable Client Signal List 673 The list is simply: 675 ::=[]... 677 Where the Generalized Protocol Identifiers (GPID) object 678 represents one of the IETF standardized GPID values as defined in 679 [RFC3471] and [RFC4328]. 681 5.3.6. Processing Capability List 683 The ProcessingCapabilities were defined in Section 5.2 as follows: 685 ::= [] 686 [] [] [] 688 The processing capability list sub-TLV is a list of processing 689 functions that the WSON network element (NE) can perform on the 690 signal including: 692 1. Number of Resources within the block 694 2. Regeneration capability 696 3. Fault and performance monitoring 698 4. Vendor Specific capability 700 Note that the code points for Fault and performance monitoring and 701 vendor specific capability are subject to further study. 703 6. Link Information (General) 705 MPLS-TE routing protocol extensions for OSPF and IS-IS [RFC3630], 706 [RFC5305] along with GMPLS routing protocol extensions for OSPF and 707 IS-IS [RFC4203, RFC5307] provide the bulk of the relatively static 708 link information needed by the RWA process. However, WSON networks 709 bring in additional link related constraints. These stem from WDM 710 line system characterization, laser transmitter tuning restrictions, 711 and switching subsystem port wavelength constraints, e.g., colored 712 ROADM drop ports. 714 In the following summarize both information from existing GMPLS 715 route protocols and new information that maybe needed by the RWA 716 process. 718 ::= [] 719 [] [] []... 720 [] [] 722 6.1. Administrative Group 724 AdministrativeGroup: Defined in [RFC3630]. Each set bit corresponds 725 to one administrative group assigned to the interface. A link may 726 belong to multiple groups. This is a configured quantity and can be 727 used to influence routing decisions. 729 6.2. Interface Switching Capability Descriptor 731 InterfaceSwCapDesc: Defined in [RFC4202], lets us know the different 732 switching capabilities on this GMPLS interface. In both [RFC4203] 733 and [RFC5307] this information gets combined with the maximum LSP 734 bandwidth that can be used on this link at eight different priority 735 levels. 737 6.3. Link Protection Type (for this link) 739 Protection: Defined in [RFC4202] and implemented in [RFC4203, 740 RFC5307]. Used to indicate what protection, if any, is guarding this 741 link. 743 6.4. Shared Risk Link Group Information 745 SRLG: Defined in [RFC4202] and implemented in [RFC4203, RFC5307]. 746 This allows for the grouping of links into shared risk groups, i.e., 747 those links that are likely, for some reason, to fail at the same 748 time. 750 6.5. Traffic Engineering Metric 752 TrafficEngineeringMetric: Defined in [RFC3630]. This allows for the 753 definition of one additional link metric value for traffic 754 engineering separate from the IP link state routing protocols link 755 metric. Note that multiple "link metric values" could find use in 756 optical networks, however it would be more useful to the RWA process 757 to assign these specific meanings such as link mile metric, or 758 probability of failure metric, etc... 760 6.6. Port Label (Wavelength) Restrictions 762 Port label (wavelength) restrictions (PortLabelRestriction) model 763 the label (wavelength) restrictions that the link and various 764 optical devices such as OXCs, ROADMs, and waveband multiplexers may 765 impose on a port. These restrictions tell us what wavelength may or 766 may not be used on a link and are relatively static. This plays an 767 important role in fully characterizing a WSON switching device 768 [Switch]. Port wavelength restrictions are specified relative to the 769 port in general or to a specific connectivity matrix (section 4.1. 770 Reference [Switch] gives an example where both switch and fixed 771 connectivity matrices are used and both types of constraints occur 772 on the same port. Such restrictions could be applied generally to 773 other label types in GMPLS by adding new kinds of restrictions. 775 ::= [...] 776 [...] 778 ::= 779 [] 781 ::= 782 [] 784 ::= [...] [] 785 [] 787 Where 789 MatrixID is the ID of the corresponding connectivity matrix (section 790 4.1. 792 The RestrictionType parameter is used to specify general port 793 restrictions and matrix specific restrictions. It can take the 794 following values and meanings: 796 SIMPLE_WAVELENGTH: Simple wavelength set restriction; The 797 wavelength set parameter is required. 799 CHANNEL_COUNT: The number of channels is restricted to be less than 800 or equal to the Max number of channels parameter (which is 801 required). 803 PORT_WAVELENGTH_EXCLUSIVITY: A wavelength can be used at most once 804 among a given set of ports. The set of ports is specified as a 805 parameter to this constraint. 807 WAVEBAND1: Waveband device with a tunable center frequency and 808 passband. This constraint is characterized by the MaxWaveBandWidth 809 parameters which indicates the maximum width of the waveband in 810 terms of channels. Note that an additional wavelength set can be 811 used to indicate the overall tuning range. Specific center frequency 812 tuning information can be obtained from dynamic channel in use 813 information. It is assumed that both center frequency and bandwidth 814 (Q) tuning can be done without causing faults in existing signals. 816 Restriction specific parameters are used with one or more of the 817 previously listed restriction types. The currently defined 818 parameters are: 820 LabelSet is a conceptual set of labels (wavelengths). 822 MaxNumChannels is the maximum number of channels that can be 823 simultaneously used (relative to either a port or a matrix). 825 MaxWaveBandWidth is the maximum width of a tunable waveband 826 switching device. 828 PortSet is a conceptual set of ports. 830 For example, if the port is a "colored" drop port of a ROADM then 831 there are two restrictions: (a) CHANNEL_COUNT, with MaxNumChannels = 832 1, and (b) SIMPLE_WAVELENGTH, with the wavelength set consisting of 833 a single member corresponding to the frequency of the permitted 834 wavelength. See [Switch] for a complete waveband example. 836 This information model for port wavelength (label) restrictions is 837 fairly general in that it can be applied to ports that have label 838 restrictions only or to ports that are part of an asymmetric switch 839 and have label restrictions. In addition, the types of label 840 restrictions that can be supported are extensible. 842 6.6.1. Port-Wavelength Exclusivity Example 844 Although there can be many different ROADM or switch architectures 845 that can lead to the constraint where a lambda (label) maybe used at 846 most once on a set of ports Figure 3 shows a ROADM architecture 847 based on components known as a Wavelength Selective Switch 848 (WSS)[OFC08]. This ROADM is composed of splitters, combiners, and 849 WSSes. This ROADM has 11 output ports, which are numbered in the 850 diagram. Output ports 1-8 are known as drop ports and are intended 851 to support a single wavelength. Drop ports 1-4 output from WSS #2, 852 which is fed from WSS #1 via a single fiber. Due to this internal 853 structure a constraint is placed on the output ports 1-4 that a 854 lambda can be only used once over the group of ports (assuming uni- 855 cast and not multi-cast operation). Similarly the output ports 5-8 856 have a similar constraint due to the internal structure. 858 | A 859 v 10 | 860 +-------+ +-------+ 861 | Split | |WSS 6 | 862 +-------+ +-------+ 863 +----+ | | | | | | | | 864 | W | | | | | | | | +-------+ +----+ 865 | S |--------------+ | | | +-----+ | +----+ | | S | 866 9 | S |----------------|---|----|-------|------|----|---| p | 867 <--| |----------------|---|----|-------|----+ | +---| l |<- 868 - 869 | 5 |--------------+ | | | +-----+ | | +--| i | 870 +----+ | | | | | +------|-|-----|--| t | 871 +--------|-+ +----|-|---|------|----+ | +----+ 872 +----+ | | | | | | | | | 873 | S |-----|--------|----------+ | | | | | | +----+ 874 | p |-----|--------|------------|---|------|----|--|--| W | 875 -->| l |-----|-----+ | +----------+ | | | +--|--| S |11 876 | i |---+ | | | | +------------|------|-------|--| S |-- 877 > 878 | t | | | | | | | | | | +---|--| | 879 +----+ | | +---|--|-|-|------------|------|-|-|---+ | 7 | 880 | | | +--|-|-|--------+ | | | | | +----+ 881 | | | | | | | | | | | | 882 +------+ +------+ +------+ +------+ 883 | WSS 1| | Split| | WSS 3| | Split| 884 +--+---+ +--+---+ +--+---+ +--+---+ 885 | A | A 886 v | v | 887 +-------+ +--+----+ +-------+ +--+----+ 888 | WSS 2 | | Comb. | | WSS 4 | | Comb. | 889 +-------+ +-------+ +-------+ +-------+ 890 1|2|3|4| A A A A 5|6|7|8| A A A A 891 v v v v | | | | v v v v | | | | 893 Figure 3 A ROADM composed from splitter, combiners, and WSSs. 895 7. Dynamic Components of the Information Model 897 In the previously presented information model there are a limited 898 number of information elements that are dynamic, i.e., subject to 899 change with subsequent establishment and teardown of connections. 900 Depending on the protocol used to convey this overall information 901 model it may be possible to send this dynamic information separate 902 from the relatively larger amount of static information needed to 903 characterize WSON's and their network elements. 905 7.1. Dynamic Link Information (General) 907 For WSON links wavelength availability and wavelengths in use for 908 shared backup purposes can be considered dynamic information and 909 hence are grouped with the dynamic information in the following set: 911 ::= 912 [] 914 AvailableLabels is a set of labels (wavelengths) currently available 915 on the link. Given this information and the port wavelength 916 restrictions one can also determine which wavelengths are currently 917 in use. This parameter could potential be used with other 918 technologies that GMPLS currently covers or may cover in the future. 920 SharedBackupLabels is a set of labels (wavelengths) currently used 921 for shared backup protection on the link. An example usage of this 922 information in a WSON setting is given in [Shared]. This parameter 923 could potential be used with other technologies that GMPLS currently 924 covers or may cover in the future. 926 7.2. Dynamic Node Information (WSON Specific) 928 Currently the only node information that can be considered dynamic 929 is the resource pool state and can be isolated into a dynamic node 930 information element as follows: 932 ::= [] 934 8. Security Considerations 936 This document discussed an information model for RWA computation in 937 WSONs. Such a model is very similar from a security standpoint of 938 the information that can be currently conveyed via GMPLS routing 939 protocols. Such information includes network topology, link state 940 and current utilization, and well as the capabilities of switches 941 and routers within the network. As such this information should be 942 protected from disclosure to unintended recipients. In addition, 943 the intentional modification of this information can significantly 944 affect network operations, particularly due to the large capacity of 945 the optical infrastructure to be controlled. 947 9. IANA Considerations 949 This informational document does not make any requests for IANA 950 action. 952 10. Acknowledgments 954 This document was prepared using 2-Word-v2.0.template.dot. 956 11. References 958 11.1. Normative References 960 [Encode] G. Bernstein, Y. Lee, D. Li, W. Imajuku, "Routing and 961 Wavelength Assignment Information Encoding for Wavelength 962 Switched Optical Networks", work in progress: draft-ietf- 963 ccamp-rwa-wson-encode. 965 [G.707] ITU-T Recommendation G.707, Network node interface for the 966 synchronous digital hierarchy (SDH), January 2007. 968 [G.709] ITU-T Recommendation G.709, Interfaces for the Optical 969 Transport Network(OTN), March 2003. 971 [G.975.1] ITU-T Recommendation G.975.1, Forward error correction for 972 high bit-rate DWDM submarine systems, February 2004. 974 [RBNF] A. Farrel, "Reduced Backus-Naur Form (RBNF) A Syntax Used 975 in Various Protocol Specifications", RFC 5511, April 2009. 977 [RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label 978 Switching (GMPLS) Signaling Functional Description", RFC 979 3471, January 2003. 981 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 982 (TE) Extensions to OSPF Version 2", RFC 3630, September 983 2003. 985 [RFC4202] Kompella, K., Ed., and Y. Rekhter, Ed., "Routing 986 Extensions in Support of Generalized Multi-Protocol Label 987 Switching (GMPLS)", RFC 4202, October 2005 989 [RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions 990 in Support of Generalized Multi-Protocol Label Switching 991 (GMPLS)", RFC 4203, October 2005. 993 [RFC4328] Papadimitriou, D., Ed., "Generalized Multi-Protocol Label 994 Switching (GMPLS) Signaling Extensions for G.709 Optical 995 Transport Networks Control", RFC 4328, January 2006. 997 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 998 Engineering", RFC 5305, October 2008. 1000 [RFC5307] Kompella, K., Ed., and Y. Rekhter, Ed., "IS-IS Extensions 1001 in Support of Generalized Multi-Protocol Label Switching 1002 (GMPLS)", RFC 5307, October 2008. 1004 11.2. Informative References 1006 [OFC08] P. Roorda and B. Collings, "Evolution to Colorless and 1007 Directionless ROADM Architectures," Optical Fiber 1008 communication/National Fiber Optic Engineers Conference, 1009 2008. OFC/NFOEC 2008. Conference on, 2008, pp. 1-3. 1011 [Shared] G. Bernstein, Y. Lee, "Shared Backup Mesh Protection in 1012 PCE-based WSON Networks", iPOP 2008, http://www.grotto- 1013 networking.com/wson/iPOP2008_WSON-shared-mesh-poster.pdf . 1015 [Switch] G. Bernstein, Y. Lee, A. Gavler, J. Martensson, " Modeling 1016 WDM Wavelength Switching Systems for Use in GMPLS and 1017 Automated Path Computation", Journal of Optical 1018 Communications and Networking, vol. 1, June, 2009, pp. 1019 187-195. 1021 [G.Sup39] ITU-T Series G Supplement 39, Optical system design and 1022 engineering considerations, February 2006. 1024 [RFC6163] Y. Lee, G. Bernstein, W. Imajuku, "Framework for GMPLS 1025 and PCE Control of Wavelength Switched Optical Networks", 1026 RFC 6163, April 2011. 1028 12. Contributors 1030 Diego Caviglia 1031 Ericsson 1032 Via A. Negrone 1/A 16153 1033 Genoa Italy 1035 Phone: +39 010 600 3736 1036 Email: diego.caviglia@(marconi.com, ericsson.com) 1038 Anders Gavler 1039 Acreo AB 1040 Electrum 236 1041 SE - 164 40 Kista Sweden 1043 Email: Anders.Gavler@acreo.se 1045 Jonas Martensson 1046 Acreo AB 1047 Electrum 236 1048 SE - 164 40 Kista, Sweden 1050 Email: Jonas.Martensson@acreo.se 1052 Itaru Nishioka 1053 NEC Corp. 1054 1753 Simonumabe, Nakahara-ku, Kawasaki, Kanagawa 211-8666 1055 Japan 1057 Phone: +81 44 396 3287 1058 Email: i-nishioka@cb.jp.nec.com 1060 Lyndon Ong 1061 Ciena 1062 Email: lyong@ciena.com 1064 Cyril Margaria 1065 Nokia Siemens Networks 1066 St Martin Strasse 76 1067 Munich, 81541 1068 Germany 1069 Phone: +49 89 5159 16934 1070 Email: cyril.margaria@nsn.com 1072 Author's Addresses 1074 Greg M. Bernstein (ed.) 1075 Grotto Networking 1076 Fremont California, USA 1078 Phone: (510) 573-2237 1079 Email: gregb@grotto-networking.com 1081 Young Lee (ed.) 1082 Huawei Technologies 1083 1700 Alma Drive, Suite 100 1084 Plano, TX 75075 1085 USA 1087 Phone: (972) 509-5599 (x2240) 1088 Email: ylee@huawei.com 1090 Dan Li 1091 Huawei Technologies Co., Ltd. 1092 F3-5-B R&D Center, Huawei Base, 1093 Bantian, Longgang District 1094 Shenzhen 518129 P.R.China 1096 Phone: +86-755-28973237 1097 Email: danli@huawei.com 1099 Wataru Imajuku 1100 NTT Network Innovation Labs 1101 1-1 Hikari-no-oka, Yokosuka, Kanagawa 1102 Japan 1104 Phone: +81-(46) 859-4315 1105 Email: imajuku.wataru@lab.ntt.co.jp 1107 Intellectual Property Statement 1109 The IETF Trust takes no position regarding the validity or scope of 1110 any Intellectual Property Rights or other rights that might be 1111 claimed to pertain to the implementation or use of the technology 1112 described in any IETF Document or the extent to which any license 1113 under such rights might or might not be available; nor does it 1114 represent that it has made any independent effort to identify any 1115 such rights. 1117 Copies of Intellectual Property disclosures made to the IETF 1118 Secretariat and any assurances of licenses to be made available, or 1119 the result of an attempt made to obtain a general license or 1120 permission for the use of such proprietary rights by implementers or 1121 users of this specification can be obtained from the IETF on-line 1122 IPR repository at http://www.ietf.org/ipr 1124 The IETF invites any interested party to bring to its attention any 1125 copyrights, patents or patent applications, or other proprietary 1126 rights that may cover technology that may be required to implement 1127 any standard or specification contained in an IETF Document. 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