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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Missing Reference: 'G.7715' is mentioned on line 404, but not defined == Unused Reference: 'G.707' is defined on line 949, but no explicit reference was found in the text == Unused Reference: 'G.709' is defined on line 952, but no explicit reference was found in the text == Unused Reference: 'G.975.1' is defined on line 955, but no explicit reference was found in the text == Unused Reference: 'G.Sup39' is defined on line 1005, but no explicit reference was found in the text Summary: 0 errors (**), 0 flaws (~~), 6 warnings (==), 2 comments (--). 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: February 2013 Grotto Networking 5 D. Li 6 Huawei 7 W. Imajuku 8 NTT 10 August 8, 2012 12 Routing and Wavelength Assignment Information Model for Wavelength 13 Switched Optical Networks 15 draft-ietf-ccamp-rwa-info-15.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 September 8, 2012. 40 Copyright Notice 42 Copyright (c) 2012 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 1.1.13. Changes from 13.....................................6 84 1.1.14. Changes from 14.....................................6 85 2. Terminology....................................................6 86 3. Routing and Wavelength Assignment Information Model............7 87 3.1. Dynamic and Relatively Static Information.................7 88 4. Node Information (General).....................................8 89 4.1. Connectivity Matrix.......................................8 90 4.2. Shared Risk Node Group....................................9 91 5. Node Information (WSON specific)..............................10 92 5.1. Resource Accessibility/Availability......................11 93 5.2. Resource Signal Constraints and Processing Capabilities..14 94 5.3. Compatibility and Capability Details.....................15 95 5.3.1. Shared Input or Output Indication...................15 96 5.3.2. Optical Interface Class List........................15 97 5.3.3. Acceptable Client Signal List.......................15 98 5.3.4. Processing Capability List..........................15 99 6. Link Information (General)....................................16 100 6.1. Administrative Group.....................................16 101 6.2. Interface Switching Capability Descriptor................16 102 6.3. Link Protection Type (for this link).....................16 103 6.4. Shared Risk Link Group Information.......................16 104 6.5. Traffic Engineering Metric...............................17 105 6.6. Port Label (Wavelength) Restrictions.....................17 106 6.6.1. Port-Wavelength Exclusivity Example.................19 107 7. Dynamic Components of the Information Model...................20 108 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 1.1.13. Changes from 13 261 Section 7.1: Clarified that this information model does not dictate 262 placement of information elements in protocols. In particular, added 263 a caveat that the available label information element may be placed 264 within the ISCD information element in the case of OSPF. 266 1.1.14. Changes from 14 268 OIC change requested by workgroup. 270 2. Terminology 272 CWDM: Coarse Wavelength Division Multiplexing. 274 DWDM: Dense Wavelength Division Multiplexing. 276 FOADM: Fixed Optical Add/Drop Multiplexer. 278 ROADM: Reconfigurable Optical Add/Drop Multiplexer. A reduced port 279 count wavelength selective switching element featuring input and 280 output line side ports as well as add/drop side ports. 282 RWA: Routing and Wavelength Assignment. 284 Wavelength Conversion. The process of converting an information 285 bearing optical signal centered at a given wavelength to one with 286 "equivalent" content centered at a different wavelength. Wavelength 287 conversion can be implemented via an optical-electronic-optical 288 (OEO) process or via a strictly optical process. 290 WDM: Wavelength Division Multiplexing. 292 Wavelength Switched Optical Network (WSON): A WDM based optical 293 network in which switching is performed selectively based on the 294 center wavelength of an optical signal. 296 3. Routing and Wavelength Assignment Information Model 298 The following WSON RWA information model is grouped into four 299 categories regardless of whether they stem from a switching 300 subsystem or from a line subsystem: 302 o Node Information 304 o Link Information 306 o Dynamic Node Information 308 o Dynamic Link Information 310 Note that this is roughly the categorization used in [G.7715] 311 section 7. 313 In the following, where applicable, the reduced Backus-Naur form 314 (RBNF) syntax of [RBNF] is used to aid in defining the RWA 315 information model. 317 3.1. Dynamic and Relatively Static Information 319 All the RWA information of concern in a WSON network is subject to 320 change over time. Equipment can be upgraded; links may be placed in 321 or out of service and the like. However, from the point of view of 322 RWA computations there is a difference between information that can 323 change with each successive connection establishment in the network 324 and that information that is relatively static on the time scales of 325 connection establishment. A key example of the former is link 326 wavelength usage since this can change with connection 327 setup/teardown and this information is a key input to the RWA 328 process. Examples of relatively static information are the 329 potential port connectivity of a WDM ROADM, and the channel spacing 330 on a WDM link. 332 This document separates, where possible, dynamic and static 333 information so that these can be kept separate in possible encodings 334 and hence allowing for separate updates of these two types of 335 information thereby reducing processing and traffic load caused by 336 the timely distribution of the more dynamic RWA WSON information. 338 4. Node Information (General) 340 The node information described here contains the relatively static 341 information related to a WSON node. This includes connectivity 342 constraints amongst ports and wavelengths since WSON switches can 343 exhibit asymmetric switching properties. Additional information 344 could include properties of wavelength converters in the node if any 345 are present. In [Switch] it was shown that the wavelength 346 connectivity constraints for a large class of practical WSON devices 347 can be modeled via switched and fixed connectivity matrices along 348 with corresponding switched and fixed port constraints. These 349 connectivity matrices are included with the node information while 350 the switched and fixed port wavelength constraints are included with 351 the link information. 353 Formally, 355 ::= [...] 357 Where the Node_ID would be an appropriate identifier for the node 358 within the WSON RWA context. 360 Note that multiple connectivity matrices are allowed and hence can 361 fully support the most general cases enumerated in [Switch]. 363 4.1. Connectivity Matrix 365 The connectivity matrix (ConnectivityMatrix) represents either the 366 potential connectivity matrix for asymmetric switches (e.g. ROADMs 367 and such) or fixed connectivity for an asymmetric device such as a 368 multiplexer. Note that this matrix does not represent any particular 369 internal blocking behavior but indicates which inputinput ports and 370 wavelengths could possibly be connected to a particular output port. 371 Representing internal state dependent blocking for a switch or ROADM 372 is beyond the scope of this document and due to its highly 373 implementation dependent nature would most likely not be subject to 374 standardization in the future. The connectivity matrix is a 375 conceptual M by N matrix representing the potential switched or 376 fixed connectivity, where M represents the number of inputinput 377 ports and N the number of outputoutput ports. This is a "conceptual" 378 matrix since the matrix tends to exhibit structure that allows for 379 very compact representations that are useful for both transmission 380 and path computation [Encode]. 382 Note that the connectivity matrix information element can be useful 383 in any technology context where asymmetric switches are utilized. 385 ConnectivityMatrix ::= 387 Where 389 is a unique identifier for the matrix. 391 can be either 0 or 1 depending upon whether the 392 connectivity is either fixed or potentially switched. 394 represents the fixed or switched connectivity in that 395 Matrix(i, j) = 0 or 1 depending on whether inputinput port i can 396 connect to outputoutput port j for one or more wavelengths. 398 4.2. Shared Risk Node Group 400 SRNG: Shared risk group for nodes. The concept of a shared risk link 401 group was defined in [RFC4202]. This can be used to achieve a 402 desired "amount" of link diversity. It is also desirable to have a 403 similar capability to achieve various degrees of node diversity. 404 This is explained in [G.7715]. Typical risk groupings for nodes can 405 include those nodes in the same building, within the same city, or 406 geographic region. 408 Since the failure of a node implies the failure of all links 409 associated with that node a sufficiently general shared risk link 410 group (SRLG) encoding, such as that used in GMPLS routing extensions 411 can explicitly incorporate SRNG information. 413 5. Node Information (WSON specific) 415 As discussed in [RFC6163] a WSON node may contain electro-optical 416 subsystems such as regenerators, wavelength converters or entire 417 switching subsystems. The model present here can be used in 418 characterizing the accessibility and availability of limited 419 resources such as regenerators or wavelength converters as well as 420 WSON signal attribute constraints of electro-optical subsystems. As 421 such this information element is fairly specific to WSON 422 technologies. 424 A WSON node may include regenerators or wavelength converters 425 arranged in a shared pool. As discussed in [RFC6163] this can 426 include OEO based WDM switches as well. There are a number of 427 different approaches used in the design of WDM switches containing 428 regenerator or converter pools. However, from the point of view of 429 path computation the following need to be known: 431 1. The nodes that support regeneration or wavelength conversion. 433 2. The accessibility and availability of a wavelength converter to 434 convert from a given inputinput wavelength on a particular 435 inputinput port to a desired outputoutput wavelength on a 436 particular outputoutput port. 438 3. Limitations on the types of signals that can be converted and the 439 conversions that can be performed. 441 Since resources tend to be packaged together in blocks of similar 442 devices, e.g., on line cards or other types of modules, the 443 fundamental unit of identifiable resource in this document is the 444 "resource block". A resource block may contain one or more 445 resources. As resources are the smallest identifiable unit of 446 processing resource, one can group together resources into blocks if 447 they have similar characteristics relevant to the optical system 448 being modeled, e.g., processing properties, accessibility, etc. 450 This leads to the following formal high level model: 452 ::= [...] 453 [] 455 Where 457 ::= ... 458 [...] [...] 459 [] 460 First the accessibility of resource blocks is addressed then their 461 properties are discussed. 463 5.1. Resource Accessibility/Availability 465 A similar technique as used to model ROADMs and optical switches can 466 be used to model regenerator/converter accessibility. This technique 467 was generally discussed in [RFC6163] and consisted of a matrix to 468 indicate possible connectivity along with wavelength constraints for 469 links/ports. Since regenerators or wavelength converters may be 470 considered a scarce resource it is desirable that the model include, 471 if desired, the usage state (availability) of individual 472 regenerators or converters in the pool. Models that incorporate more 473 state to further reveal blocking conditions on input or output to 474 particular converters are for further study and not included here. 476 The three stage model is shown schematically in Figure 1 and Figure 477 2. The difference between the two figures is that Figure 1 assumes 478 that each signal that can get to a resource block may do so, while 479 in Figure 2 the access to sets of resource blocks is via a shared 480 fiber which imposes its own wavelength collision constraint. The 481 representation of Figure 1 can have more than one input to each 482 resource block since each input represents a single wavelength 483 signal, while in Figure 2 shows a single multiplexed WDM inputinput 484 or output, e.g., a fiber, to/from each set of block. 486 This model assumes N input ports (fibers), P resource blocks 487 containing one or more identical resources (e.g. wavelength 488 converters), and M output ports (fibers). Since not all input ports 489 can necessarily reach each resource block, the model starts with a 490 resource pool input matrix RI(i,p) = {0,1} whether input port i can 491 reach potentially reach resource block p. 493 Since not all wavelengths can necessarily reach all the resources or 494 the resources may have limited input wavelength range the model has 495 a set of relatively static input port constraints for each resource. 496 In addition, if the access to a set of resource blocks is via a 497 shared fiber (Figure 2) this would impose a dynamic wavelength 498 availability constraint on that shared fiber. The resource block 499 input port constraint is modeled via a static wavelength set 500 mechanism and the case of shared access to a set of blocks is 501 modeled via a dynamic wavelength set mechanism. 503 Next a state vector RA(j) = {0,...,k} is used to track the number of 504 resources in resource block j in use. This is the only state kept in 505 the resource pool model. This state is not necessary for modeling 506 "fixed" transponder system or full OEO switches with WDM interfaces, 507 i.e., systems where there is no sharing. 509 After that, a set of static resource output wavelength constraints 510 and possibly dynamic shared output fiber constraints maybe used. The 511 static constraints indicate what wavelengths a particular resource 512 block can generate or are restricted to generating e.g., a fixed 513 regenerator would be limited to a single lambda. The dynamic 514 constraints would be used in the case where a single shared fiber is 515 used to output the resource block (Figure 2). 517 Finally, to complete the model, a resource pool output matrix 518 RE(p,k) = {0,1} depending on whether the output from resource block 519 p can reach output port k, may be used. 521 I1 +-------------+ +-------------+ E1 522 ----->| | +--------+ | |-----> 523 I2 | +------+ Rb #1 +-------+ | E2 524 ----->| | +--------+ | |-----> 525 | | | | 526 | Resource | +--------+ | Resource | 527 | Pool +------+ +-------+ Pool | 528 | | + Rb #2 + | | 529 | Input +------+ +-------| Output | 530 | Connection | +--------+ | Connection | 531 | Matrix | . | Matrix | 532 | | . | | 533 | | . | | 534 IN | | +--------+ | | EM 535 ----->| +------+ Rb #P +-------+ |-----> 536 | | +--------+ | | 537 +-------------+ ^ ^ +-------------+ 538 | | 539 | | 540 | | 541 | | 543 Input wavelength Output wavelength 544 constraints for constraints for 545 each resource each resource 547 Figure 1 Schematic diagram of resource pool model. 549 I1 +-------------+ +-------------+ E1 550 ----->| | +--------+ | |-----> 551 I2 | +======+ Rb #1 +-+ + | E2 552 ----->| | +--------+ | | |-----> 553 | | |=====| | 554 | Resource | +--------+ | | Resource | 555 | Pool | +-+ Rb #2 +-+ | Pool | 556 | | | +--------+ + | 557 | Input |====| | Output | 558 | Connection | | +--------+ | Connection | 559 | Matrix | +-| Rb #3 |=======| Matrix | 560 | | +--------+ | | 561 | | . | | 562 | | . | | 563 | | . | | 564 IN | | +--------+ | | EM 565 ----->| +======+ Rb #P +=======+ |-----> 566 | | +--------+ | | 567 +-------------+ ^ ^ +-------------+ 568 | | 569 | | 570 | | 571 Single (shared) fibers for block input and output 573 Input wavelength Output wavelength 574 availability for availability for 575 each block input fiber each block output fiber 577 Figure 2 Schematic diagram of resource pool model with shared block 578 accessibility. 580 Formally the model can be specified as: 582 584 ::= 585 587 588 ::=()... 591 Note that except for all the other components of 592 are relatively static. Also the 593 and are only used 594 in the cases of shared input or output access to the particular 595 block. See the resource block information in the next section to see 596 how this is specified. 598 5.2. Resource Signal Constraints and Processing Capabilities 600 The wavelength conversion abilities of a resource (e.g. regenerator, 601 wavelength converter) were modeled in the 602 previously discussed. As discussed in [RFC6163] the constraints on 603 an electro-optical resource can be modeled in terms of input 604 constraints, processing capabilities, and output constraints: 606 ::= ([] 607 [] )* 609 Where is a list of resource block identifiers with 610 the same characteristics. If this set is missing the constraints are 611 applied to the entire network element. 613 The are signal compatibility based constraints 614 and/or shared access constraint indication. The details of these 615 constraints are defined in section 5.3. 617 ::= [] 618 [] 620 The are important operations that the 621 resource (or network element) can perform on the signal. The details 622 of these capabilities are defined in section 5.3. 624 ::= [] 625 [] [] [] 627 The are either restrictions on the properties of 628 the signal leaving the block, options concerning the signal 629 properties when leaving the resource or shared fiber output 630 constraint indication. 632 := [] 633 5.3. Compatibility and Capability Details 635 5.3.1. Shared Input or Output Indication 637 As discussed in the previous section and shown in Figure 2 the input 638 or output access to a resource block may be via a shared fiber. The 639 and elements are indicators for this 640 condition with respect to the block being described. 642 5.3.2. Optical Interface Class List 644 ::= ... 646 Where the term is defined by [xyz?]. 648 5.3.3. Acceptable Client Signal List 650 The list is simply: 652 ::=[]... 654 Where the Generalized Protocol Identifiers (GPID) object 655 represents one of the IETF standardized GPID values as defined in 656 [RFC3471] and [RFC4328]. 658 5.3.4. Processing Capability List 660 The ProcessingCapabilities were defined in Section 5.2 as follows: 662 ::= [] 663 [] [] [] 665 The processing capability list sub-TLV is a list of processing 666 functions that the WSON network element (NE) can perform on the 667 signal including: 669 1. Number of Resources within the block 671 2. Regeneration capability 673 3. Fault and performance monitoring 675 4. Vendor Specific capability 677 Note that the code points for Fault and performance monitoring and 678 vendor specific capability are subject to further study. 680 6. Link Information (General) 682 MPLS-TE routing protocol extensions for OSPF and IS-IS [RFC3630], 683 [RFC5305] along with GMPLS routing protocol extensions for OSPF and 684 IS-IS [RFC4203, RFC5307] provide the bulk of the relatively static 685 link information needed by the RWA process. However, WSON networks 686 bring in additional link related constraints. These stem from WDM 687 line system characterization, laser transmitter tuning restrictions, 688 and switching subsystem port wavelength constraints, e.g., colored 689 ROADM drop ports. 691 In the following summarize both information from existing GMPLS 692 route protocols and new information that maybe needed by the RWA 693 process. 695 ::= [] 696 [] [] []... 697 [] [] 699 6.1. Administrative Group 701 AdministrativeGroup: Defined in [RFC3630]. Each set bit corresponds 702 to one administrative group assigned to the interface. A link may 703 belong to multiple groups. This is a configured quantity and can be 704 used to influence routing decisions. 706 6.2. Interface Switching Capability Descriptor 708 InterfaceSwCapDesc: Defined in [RFC4202], lets us know the different 709 switching capabilities on this GMPLS interface. In both [RFC4203] 710 and [RFC5307] this information gets combined with the maximum LSP 711 bandwidth that can be used on this link at eight different priority 712 levels. 714 6.3. Link Protection Type (for this link) 716 Protection: Defined in [RFC4202] and implemented in [RFC4203, 717 RFC5307]. Used to indicate what protection, if any, is guarding this 718 link. 720 6.4. Shared Risk Link Group Information 722 SRLG: Defined in [RFC4202] and implemented in [RFC4203, RFC5307]. 723 This allows for the grouping of links into shared risk groups, i.e., 724 those links that are likely, for some reason, to fail at the same 725 time. 727 6.5. Traffic Engineering Metric 729 TrafficEngineeringMetric: Defined in [RFC3630]. This allows for the 730 definition of one additional link metric value for traffic 731 engineering separate from the IP link state routing protocols link 732 metric. Note that multiple "link metric values" could find use in 733 optical networks, however it would be more useful to the RWA process 734 to assign these specific meanings such as link mile metric, or 735 probability of failure metric, etc... 737 6.6. Port Label (Wavelength) Restrictions 739 Port label (wavelength) restrictions (PortLabelRestriction) model 740 the label (wavelength) restrictions that the link and various 741 optical devices such as OXCs, ROADMs, and waveband multiplexers may 742 impose on a port. These restrictions tell us what wavelength may or 743 may not be used on a link and are relatively static. This plays an 744 important role in fully characterizing a WSON switching device 745 [Switch]. Port wavelength restrictions are specified relative to the 746 port in general or to a specific connectivity matrix (section 4.1. 747 Reference [Switch] gives an example where both switch and fixed 748 connectivity matrices are used and both types of constraints occur 749 on the same port. Such restrictions could be applied generally to 750 other label types in GMPLS by adding new kinds of restrictions. 752 ::= [...] 753 [...] 755 ::= 756 [] 758 ::= 759 [] 761 ::= [...] [] 762 [] 764 Where 766 MatrixID is the ID of the corresponding connectivity matrix (section 767 4.1. 769 The RestrictionType parameter is used to specify general port 770 restrictions and matrix specific restrictions. It can take the 771 following values and meanings: 773 SIMPLE_WAVELENGTH: Simple wavelength set restriction; The 774 wavelength set parameter is required. 776 CHANNEL_COUNT: The number of channels is restricted to be less than 777 or equal to the Max number of channels parameter (which is 778 required). 780 PORT_WAVELENGTH_EXCLUSIVITY: A wavelength can be used at most once 781 among a given set of ports. The set of ports is specified as a 782 parameter to this constraint. 784 WAVEBAND1: Waveband device with a tunable center frequency and 785 passband. This constraint is characterized by the MaxWaveBandWidth 786 parameters which indicates the maximum width of the waveband in 787 terms of channels. Note that an additional wavelength set can be 788 used to indicate the overall tuning range. Specific center frequency 789 tuning information can be obtained from dynamic channel in use 790 information. It is assumed that both center frequency and bandwidth 791 (Q) tuning can be done without causing faults in existing signals. 793 Restriction specific parameters are used with one or more of the 794 previously listed restriction types. The currently defined 795 parameters are: 797 LabelSet is a conceptual set of labels (wavelengths). 799 MaxNumChannels is the maximum number of channels that can be 800 simultaneously used (relative to either a port or a matrix). 802 MaxWaveBandWidth is the maximum width of a tunable waveband 803 switching device. 805 PortSet is a conceptual set of ports. 807 For example, if the port is a "colored" drop port of a ROADM then 808 there are two restrictions: (a) CHANNEL_COUNT, with MaxNumChannels = 809 1, and (b) SIMPLE_WAVELENGTH, with the wavelength set consisting of 810 a single member corresponding to the frequency of the permitted 811 wavelength. See [Switch] for a complete waveband example. 813 This information model for port wavelength (label) restrictions is 814 fairly general in that it can be applied to ports that have label 815 restrictions only or to ports that are part of an asymmetric switch 816 and have label restrictions. In addition, the types of label 817 restrictions that can be supported are extensible. 819 6.6.1. Port-Wavelength Exclusivity Example 821 Although there can be many different ROADM or switch architectures 822 that can lead to the constraint where a lambda (label) maybe used at 823 most once on a set of ports Figure 3 shows a ROADM architecture 824 based on components known as a Wavelength Selective Switch 825 (WSS)[OFC08]. This ROADM is composed of splitters, combiners, and 826 WSSes. This ROADM has 11 output ports, which are numbered in the 827 diagram. Output ports 1-8 are known as drop ports and are intended 828 to support a single wavelength. Drop ports 1-4 output from WSS #2, 829 which is fed from WSS #1 via a single fiber. Due to this internal 830 structure a constraint is placed on the output ports 1-4 that a 831 lambda can be only used once over the group of ports (assuming uni- 832 cast and not multi-cast operation). Similarly the output ports 5-8 833 have a similar constraint due to the internal structure. 835 | A 836 v 10 | 837 +-------+ +-------+ 838 | Split | |WSS 6 | 839 +-------+ +-------+ 840 +----+ | | | | | | | | 841 | W | | | | | | | | +-------+ +----+ 842 | S |--------------+ | | | +-----+ | +----+ | | S | 843 9 | S |----------------|---|----|-------|------|----|---| p | 844 <--| |----------------|---|----|-------|----+ | +---| l |<- 845 - 846 | 5 |--------------+ | | | +-----+ | | +--| i | 847 +----+ | | | | | +------|-|-----|--| t | 848 +--------|-+ +----|-|---|------|----+ | +----+ 849 +----+ | | | | | | | | | 850 | S |-----|--------|----------+ | | | | | | +----+ 851 | p |-----|--------|------------|---|------|----|--|--| W | 852 -->| l |-----|-----+ | +----------+ | | | +--|--| S |11 853 | i |---+ | | | | +------------|------|-------|--| S |-- 854 > 855 | t | | | | | | | | | | +---|--| | 856 +----+ | | +---|--|-|-|------------|------|-|-|---+ | 7 | 857 | | | +--|-|-|--------+ | | | | | +----+ 858 | | | | | | | | | | | | 859 +------+ +------+ +------+ +------+ 860 | WSS 1| | Split| | WSS 3| | Split| 861 +--+---+ +--+---+ +--+---+ +--+---+ 862 | A | A 863 v | v | 864 +-------+ +--+----+ +-------+ +--+----+ 865 | WSS 2 | | Comb. | | WSS 4 | | Comb. | 866 +-------+ +-------+ +-------+ +-------+ 867 1|2|3|4| A A A A 5|6|7|8| A A A A 868 v v v v | | | | v v v v | | | | 870 Figure 3 A ROADM composed from splitter, combiners, and WSSs. 872 7. Dynamic Components of the Information Model 874 In the previously presented information model there are a limited 875 number of information elements that are dynamic, i.e., subject to 876 change with subsequent establishment and teardown of connections. 877 Depending on the protocol used to convey this overall information 878 model it may be possible to send this dynamic information separate 879 from the relatively larger amount of static information needed to 880 characterize WSON's and their network elements. 882 7.1. Dynamic Link Information (General) 884 For WSON links wavelength availability and wavelengths in use for 885 shared backup purposes can be considered dynamic information and 886 hence are grouped with the dynamic information in the following set: 888 ::= 889 [] 891 AvailableLabels is a set of labels (wavelengths) currently available 892 on the link. Given this information and the port wavelength 893 restrictions one can also determine which wavelengths are currently 894 in use. This parameter could potential be used with other 895 technologies that GMPLS currently covers or may cover in the future. 897 SharedBackupLabels is a set of labels (wavelengths) currently used 898 for shared backup protection on the link. An example usage of this 899 information in a WSON setting is given in [Shared]. This parameter 900 could potential be used with other technologies that GMPLS currently 901 covers or may cover in the future. 903 Note that the above does not dictate a particular encoding or 904 placement for available label information. In some routing protocols 905 it may be advantageous or required to place this information within 906 another information element such as the interface switching 907 capability descriptor (ISCD). Consult routing protocol specific 908 extensions for details of placement of information elements. 910 7.2. Dynamic Node Information (WSON Specific) 912 Currently the only node information that can be considered dynamic 913 is the resource pool state and can be isolated into a dynamic node 914 information element as follows: 916 ::= [] 918 8. Security Considerations 920 This document discussed an information model for RWA computation in 921 WSONs. Such a model is very similar from a security standpoint of 922 the information that can be currently conveyed via GMPLS routing 923 protocols. Such information includes network topology, link state 924 and current utilization, and well as the capabilities of switches 925 and routers within the network. As such this information should be 926 protected from disclosure to unintended recipients. In addition, 927 the intentional modification of this information can significantly 928 affect network operations, particularly due to the large capacity of 929 the optical infrastructure to be controlled. 931 9. IANA Considerations 933 This informational document does not make any requests for IANA 934 action. 936 10. Acknowledgments 938 This document was prepared using 2-Word-v2.0.template.dot. 940 11. References 942 11.1. Normative References 944 [Encode] G. Bernstein, Y. Lee, D. Li, W. Imajuku, "Routing and 945 Wavelength Assignment Information Encoding for Wavelength 946 Switched Optical Networks", work in progress: draft-ietf- 947 ccamp-rwa-wson-encode. 949 [G.707] ITU-T Recommendation G.707, Network node interface for the 950 synchronous digital hierarchy (SDH), January 2007. 952 [G.709] ITU-T Recommendation G.709, Interfaces for the Optical 953 Transport Network(OTN), March 2003. 955 [G.975.1] ITU-T Recommendation G.975.1, Forward error correction for 956 high bit-rate DWDM submarine systems, February 2004. 958 [RBNF] A. Farrel, "Reduced Backus-Naur Form (RBNF) A Syntax Used 959 in Various Protocol Specifications", RFC 5511, April 2009. 961 [RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label 962 Switching (GMPLS) Signaling Functional Description", RFC 963 3471, January 2003. 965 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 966 (TE) Extensions to OSPF Version 2", RFC 3630, September 967 2003. 969 [RFC4202] Kompella, K., Ed., and Y. Rekhter, Ed., "Routing 970 Extensions in Support of Generalized Multi-Protocol Label 971 Switching (GMPLS)", RFC 4202, October 2005 973 [RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions 974 in Support of Generalized Multi-Protocol Label Switching 975 (GMPLS)", RFC 4203, October 2005. 977 [RFC4328] Papadimitriou, D., Ed., "Generalized Multi-Protocol Label 978 Switching (GMPLS) Signaling Extensions for G.709 Optical 979 Transport Networks Control", RFC 4328, January 2006. 981 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 982 Engineering", RFC 5305, October 2008. 984 [RFC5307] Kompella, K., Ed., and Y. Rekhter, Ed., "IS-IS Extensions 985 in Support of Generalized Multi-Protocol Label Switching 986 (GMPLS)", RFC 5307, October 2008. 988 11.2. Informative References 990 [OFC08] P. Roorda and B. Collings, "Evolution to Colorless and 991 Directionless ROADM Architectures," Optical Fiber 992 communication/National Fiber Optic Engineers Conference, 993 2008. OFC/NFOEC 2008. Conference on, 2008, pp. 1-3. 995 [Shared] G. Bernstein, Y. Lee, "Shared Backup Mesh Protection in 996 PCE-based WSON Networks", iPOP 2008, http://www.grotto- 997 networking.com/wson/iPOP2008_WSON-shared-mesh-poster.pdf . 999 [Switch] G. Bernstein, Y. Lee, A. Gavler, J. Martensson, " Modeling 1000 WDM Wavelength Switching Systems for Use in GMPLS and 1001 Automated Path Computation", Journal of Optical 1002 Communications and Networking, vol. 1, June, 2009, pp. 1003 187-195. 1005 [G.Sup39] ITU-T Series G Supplement 39, Optical system design and 1006 engineering considerations, February 2006. 1008 [RFC6163] Y. Lee, G. Bernstein, W. Imajuku, "Framework for GMPLS 1009 and PCE Control of Wavelength Switched Optical Networks", 1010 RFC 6163, April 2011. 1012 12. Contributors 1014 Diego Caviglia 1015 Ericsson 1016 Via A. Negrone 1/A 16153 1017 Genoa Italy 1019 Phone: +39 010 600 3736 1020 Email: diego.caviglia@(marconi.com, ericsson.com) 1022 Anders Gavler 1023 Acreo AB 1024 Electrum 236 1025 SE - 164 40 Kista Sweden 1027 Email: Anders.Gavler@acreo.se 1029 Jonas Martensson 1030 Acreo AB 1031 Electrum 236 1032 SE - 164 40 Kista, Sweden 1034 Email: Jonas.Martensson@acreo.se 1036 Itaru Nishioka 1037 NEC Corp. 1038 1753 Simonumabe, Nakahara-ku, Kawasaki, Kanagawa 211-8666 1039 Japan 1041 Phone: +81 44 396 3287 1042 Email: i-nishioka@cb.jp.nec.com 1044 Lyndon Ong 1045 Ciena 1046 Email: lyong@ciena.com 1048 Cyril Margaria 1049 Nokia Siemens Networks 1050 St Martin Strasse 76 1051 Munich, 81541 1052 Germany 1053 Phone: +49 89 5159 16934 1054 Email: cyril.margaria@nsn.com 1056 Author's Addresses 1058 Greg M. Bernstein (ed.) 1059 Grotto Networking 1060 Fremont California, USA 1062 Phone: (510) 573-2237 1063 Email: gregb@grotto-networking.com 1065 Young Lee (ed.) 1066 Huawei Technologies 1067 1700 Alma Drive, Suite 100 1068 Plano, TX 75075 1069 USA 1071 Phone: (972) 509-5599 (x2240) 1072 Email: ylee@huawei.com 1074 Dan Li 1075 Huawei Technologies Co., Ltd. 1076 F3-5-B R&D Center, Huawei Base, 1077 Bantian, Longgang District 1078 Shenzhen 518129 P.R.China 1080 Phone: +86-755-28973237 1081 Email: danli@huawei.com 1083 Wataru Imajuku 1084 NTT Network Innovation Labs 1085 1-1 Hikari-no-oka, Yokosuka, Kanagawa 1086 Japan 1088 Phone: +81-(46) 859-4315 1089 Email: imajuku.wataru@lab.ntt.co.jp 1091 Intellectual Property Statement 1093 The IETF Trust takes no position regarding the validity or scope of 1094 any Intellectual Property Rights or other rights that might be 1095 claimed to pertain to the implementation or use of the technology 1096 described in any IETF Document or the extent to which any license 1097 under such rights might or might not be available; nor does it 1098 represent that it has made any independent effort to identify any 1099 such rights. 1101 Copies of Intellectual Property disclosures made to the IETF 1102 Secretariat and any assurances of licenses to be made available, or 1103 the result of an attempt made to obtain a general license or 1104 permission for the use of such proprietary rights by implementers or 1105 users of this specification can be obtained from the IETF on-line 1106 IPR repository at http://www.ietf.org/ipr 1108 The IETF invites any interested party to bring to its attention any 1109 copyrights, patents or patent applications, or other proprietary 1110 rights that may cover technology that may be required to implement 1111 any standard or specification contained in an IETF Document. 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