idnits 2.17.1 draft-ietf-ccamp-rwa-info-23.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == Line 413 has weird spacing: '...t fiber eac...' -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (November 27, 2014) is 3437 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- No issues found here. Summary: 0 errors (**), 0 flaws (~~), 2 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 2015 Grotto Networking 5 D. Li 6 Huawei 7 W. Imajuku 8 NTT 10 November 27, 2014 12 Routing and Wavelength Assignment Information Model for Wavelength 13 Switched Optical Networks 15 draft-ietf-ccamp-rwa-info-23.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 February 27, 2015. 40 Copyright Notice 42 Copyright (c) 2014 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 2. Terminology....................................................3 71 3. Routing and Wavelength Assignment Information Model............4 72 3.1. Dynamic and Relatively Static Information.................4 73 4. Node Information (General).....................................5 74 4.1. Connectivity Matrix.......................................5 75 5. Node Information (WSON specific)...............................6 76 5.1. Resource Accessibility/Availability.......................7 77 5.2. Resource Signal Constraints and Processing Capabilities..11 78 5.3. Compatibility and Capability Details.....................12 79 5.3.1. Shared Input or Output Indication...................12 80 5.3.2. Optical Interface Class List........................13 81 5.3.3. Acceptable Client Signal List.......................13 82 5.3.4. Processing Capability List..........................13 83 6. Link Information (General)....................................14 84 6.1. Administrative Group.....................................14 85 6.2. Interface Switching Capability Descriptor................15 86 6.3. Link Protection Type (for this link).....................15 87 6.4. Shared Risk Link Group Information.......................15 88 6.5. Traffic Engineering Metric...............................15 89 6.6. Port Label Restrictions..................................15 90 6.6.1. Port-Wavelength Exclusivity Example.................18 91 7. Dynamic Components of the Information Model...................19 92 7.1. Dynamic Link Information (General).......................20 93 7.2. Dynamic Node Information (WSON Specific).................20 94 8. Security Considerations.......................................20 95 9. IANA Considerations...........................................21 96 10. Acknowledgments..............................................21 97 11. References...................................................22 98 11.1. Normative References....................................22 99 11.2. Informative References..................................23 100 12. Contributors.................................................24 101 Authors' Addresses...............................................25 102 Intellectual Property Statement..................................25 103 Disclaimer of Validity...........................................26 105 1. Introduction 107 The purpose of the WSONs information model described in this 108 document is to facilitate constrained lightpath computation and as 109 such is not a general purpose network management information model. 110 This constraint is frequently referred to as the "wavelength 111 continuity" constraint, and the corresponding constrained lightpath 112 computation is known as the routing and wavelength assignment (RWA) 113 problem. Hence the information model must provide sufficient 114 topology and wavelength restriction and availability information to 115 support this computation. More details on the RWA process and WSON 116 subsystems and their properties can be found in [RFC6163]. The model 117 defined here includes constraints between WSON signal attributes and 118 network elements, but does not include optical impairments. 120 In addition to presenting an information model suitable for path 121 computation in WSON, this document also highlights model aspects 122 that may have general applicability to other technologies utilizing 123 a GMPLS control plane. The portion of the information model 124 applicable to other technologies beyond WSON is referred to as 125 "general" to distinguish it from the "WSON-specific" portion that is 126 applicable only to WSON technology. 128 2. Terminology 130 Refer to [RFC6163] for Reconfigurable Optical Add/Drop Multiplexer 131 (ROADM), RWA, Wavelength Conversion, Wavelength Division 132 Multiplexing (WDM) and WSON. 134 3. Routing and Wavelength Assignment Information Model 136 The WSON RWA information model in this document is grouped into four 137 categories regardless of whether they stem from a switching 138 subsystem or from a line subsystem. A switching subsystem refers to 139 WSON nodes such as ROADM or Optical Add/Drop Multiplexer (OADM) and 140 a line subsystem refers to devices such as WDM or Optical Amplifier: 142 o Node Information 144 o Link Information 146 o Dynamic Node Information 148 o Dynamic Link Information 150 Note that this is roughly the categorization used in [G.7715] 151 section 7. 153 In the following, where applicable, the reduced Backus-Naur form 154 (RBNF) syntax of [RBNF] is used to aid in defining the RWA 155 information model. 157 3.1. Dynamic and Relatively Static Information 159 All the RWA information of concern in a WSON network is subject to 160 change over time. Equipment can be upgraded; links may be placed in 161 or out of service and the like. However, from the point of view of 162 RWA computations there is a difference between information that can 163 change with each successive connection establishment in the network 164 and that information that is relatively static and independent of 165 connection establishment. A key example of the former is link 166 wavelength usage since this can change with connection 167 setup/teardown and this information is a key input to the RWA 168 process. Examples of relatively static information are the 169 potential port connectivity of a WDM ROADM, and the channel spacing 170 on a WDM link. 172 This document separates, where possible, dynamic and static 173 information so that these can be kept separate in possible encodings 174 and hence allowing for separate updates of these two types of 175 information thereby reducing processing and traffic load caused by 176 the timely distribution of the more dynamic RWA WSON information. 178 4. Node Information (General) 180 The node information described here contains the relatively static 181 information related to a WSON node. This includes connectivity 182 constraints amongst ports and wavelengths since WSON switches can 183 exhibit asymmetric switching properties. Additional information 184 could include properties of wavelength converters in the node if any 185 are present. In [Switch] it was shown that the wavelength 186 connectivity constraints for a large class of practical WSON devices 187 can be modeled via switched and fixed connectivity matrices along 188 with corresponding switched and fixed port constraints. These 189 connectivity matrices are included with the node information while 190 the switched and fixed port wavelength constraints are included with 191 the link information. 193 Formally, 195 ::= [...] 197 Where the Node_ID would be an appropriate identifier for the node 198 within the WSON RWA context. 200 Note that multiple connectivity matrices are allowed and hence can 201 fully support the most general cases enumerated in [Switch]. 203 4.1. Connectivity Matrix 205 The connectivity matrix (ConnectivityMatrix) represents either the 206 potential connectivity matrix for asymmetric switches (e.g. ROADMs 207 and such) or fixed connectivity for an asymmetric device such as a 208 multiplexer. Note that this matrix does not represent any particular 209 internal blocking behavior but indicates which input ports and 210 wavelengths could possibly be connected to a particular output port. 211 Representing internal state dependent blocking for a switch or ROADM 212 is beyond the scope of this document and due to its highly 213 implementation dependent nature would most likely not be subject to 214 standardization in the future. The connectivity matrix is a 215 conceptual M by N matrix representing the potential switched or 216 fixed connectivity, where M represents the number of input ports and 217 N the number of output ports. This is a "conceptual" matrix since 218 the matrix tends to exhibit structure that allows for very compact 219 representations that are useful for both transmission and path 220 computation. 222 Note that the connectivity matrix information element can be useful 223 in any technology context where asymmetric switches are utilized. 225 ::= 227 229 231 Where 233 is a unique identifier for the matrix. 235 can be either 0 or 1 depending upon whether the 236 connectivity is either fixed or switched. 238 represents the fixed or switched connectivity in that 239 Matrix(i, j) = 0 or 1 depending on whether input port i can connect 240 to output port j for one or more wavelengths. 242 5. Node Information (WSON specific) 244 As discussed in [RFC6163] a WSON node may contain electro-optical 245 subsystems such as regenerators, wavelength converters or entire 246 switching subsystems. The model present here can be used in 247 characterizing the accessibility and availability of limited 248 resources such as regenerators or wavelength converters as well as 249 WSON signal attribute constraints of electro-optical subsystems. As 250 such this information element is fairly specific to WSON 251 technologies. 253 A WSON node may include regenerators or wavelength converters 254 arranged in a shared pool. As discussed in [RFC6163] this can 255 include OEO based WDM switches as well. There are a number of 256 different approaches used in the design of WDM switches containing 257 regenerator or converter pools. However, from the point of view of 258 path computation the following need to be known: 260 1. The nodes that support regeneration or wavelength conversion. 262 2. The accessibility and availability of a wavelength converter to 263 convert from a given input wavelength on a particular input port 264 to a desired output wavelength on a particular output port. 266 3. Limitations on the types of signals that can be converted and the 267 conversions that can be performed. 269 Since resources tend to be packaged together in blocks of similar 270 devices, e.g., on line cards or other types of modules, the 271 fundamental unit of identifiable resource in this document is the 272 "resource block". A resource block may contain one or more 273 resources. A resource is the smallest identifiable unit of 274 processing allocation. One can group together resources into blocks 275 if they have similar characteristics relevant to the optical system 276 being modeled, e.g., processing properties, accessibility, etc. 278 This leads to the following formal high level model: 280 ::= 282 [...] 284 [] 286 Where 288 ::= ... 290 [...] 292 [...] 294 [] 296 First the accessibility of resource blocks is addressed then their 297 properties are discussed. 299 5.1. Resource Accessibility/Availability 301 A similar technique as used to model ROADMs and optical switches can 302 be used to model regenerator/converter accessibility. This technique 303 was generally discussed in [RFC6163] and consisted of a matrix to 304 indicate possible connectivity along with wavelength constraints for 305 links/ports. Since regenerators or wavelength converters may be 306 considered a scarce resource it is desirable that the model include, 307 if desired, the usage state (availability) of individual 308 regenerators or converters in the pool. Models that incorporate more 309 state to further reveal blocking conditions on input or output to 310 particular converters are for further study and not included here. 312 The three stage model is shown schematically in Figure 1 and Figure 313 2. The difference between the two figures is that Figure 1 assumes 314 that each signal that can get to a resource block may do so, while 315 in Figure 2 the access to sets of resource blocks is via a shared 316 fiber which imposes its own wavelength collision constraint. The 317 representation of Figure 1 can have more than one input to each 318 resource block since each input represents a single wavelength 319 signal, while in Figure 2 shows a single multiplexed WDM input or 320 output, e.g., a fiber, to/from each set of block. 322 This model assumes N input ports (fibers), P resource blocks 323 containing one or more identical resources (e.g. wavelength 324 converters), and M output ports (fibers). Since not all input ports 325 can necessarily reach each resource block, the model starts with a 326 resource pool input matrix RI(i,p) = {0,1} whether input port i can 327 potentially reach resource block p. 329 Since not all wavelengths can necessarily reach all the resources or 330 the resources may have limited input wavelength range the model has 331 a set of relatively static input port constraints for each resource. 332 In addition, if the access to a set of resource blocks is via a 333 shared fiber (Figure 2) this would impose a dynamic wavelength 334 availability constraint on that shared fiber. The resource block 335 input port constraint is modeled via a static wavelength set 336 mechanism and the case of shared access to a set of blocks is 337 modeled via a dynamic wavelength set mechanism. 339 Next a state vector RA(j) = {0,...,k} is used to track the number of 340 resources in resource block j in use. This is the only state kept in 341 the resource pool model. This state is not necessary for modeling 342 "fixed" transponder system or full OEO switches with WDM interfaces, 343 i.e., systems where there is no sharing. 345 After that, a set of static resource output wavelength constraints 346 and possibly dynamic shared output fiber constraints maybe used. The 347 static constraints indicate what wavelengths a particular resource 348 block can generate or are restricted to generating e.g., a fixed 349 regenerator would be limited to a single lambda. The dynamic 350 constraints would be used in the case where a single shared fiber is 351 used to output the resource block (Figure 2). 353 Finally, to complete the model, a resource pool output matrix 354 RE(p,k) = {0,1} depending on whether the output from resource block 355 p can reach output port k, may be used. 357 I1 +-------------+ +-------------+ O1 358 ----->| | +--------+ | |-----> 359 I2 | +------+ Rb #1 +-------+ | O2 360 ----->| | +--------+ | |-----> 361 | | | | 362 | Resource | +--------+ | Resource | 363 | Pool +------+ +-------+ Pool | 364 | | + Rb #2 + | | 365 | Input +------+ +-------| Output | 366 | Connection | +--------+ | Connection | 367 | Matrix | . | Matrix | 368 | | . | | 369 | | . | | 370 IN | | +--------+ | | OM 371 ----->| +------+ Rb #P +-------+ |-----> 372 | | +--------+ | | 373 +-------------+ ^ ^ +-------------+ 374 | | 375 | | 376 | | 377 | | 379 Input wavelength Output wavelength 380 constraints for constraints for 381 each resource each resource 383 Note: Rb is a Resource Block. 385 Figure 1 Schematic diagram of resource pool model. 387 I1 +-------------+ +-------------+ O1 388 ----->| | +--------+ | |-----> 389 I2 | +======+ Rb #1 +-+ | | O2 390 ----->| | +--------+ | | |-----> 391 | | |=====| | 392 | Resource | +--------+ | | Resource | 393 | Pool | +-+ Rb #2 +-+ | Pool | 394 | | | +--------+ | | 395 | Input |====| | Output | 396 | Connection | | +--------+ | Connection | 397 | Matrix | +-| Rb #3 |=======| Matrix | 398 | | +--------+ | | 399 | | . | | 400 | | . | | 401 | | . | | 402 IN | | +--------+ | | OM 403 ----->| +======+ Rb #P +=======+ |-----> 404 | | +--------+ | | 405 +-------------+ ^ ^ +-------------+ 406 | | 407 | | 408 | | 409 Single (shared) fibers for block input and output 411 Input wavelength Output wavelength 412 availability for availability for 413 each block input fiber each block output fiber 415 Note: Rb is a Resource Block. 417 Figure 2 Schematic diagram of resource pool model with shared block 418 accessibility. 420 Formally the model can be specified as: 422 ::= 424 426 ::= 428 430 ::= [] 432 [] 434 ::= 436 438 [] 440 [] 442 Note that except for all the other components of 443 are relatively static. Also the 444 and are only used 445 in the cases of shared input or output access to the particular 446 block. See the resource block information in the next section to see 447 how this is specified. 449 5.2. Resource Signal Constraints and Processing Capabilities 451 The wavelength conversion abilities of a resource (e.g. regenerator, 452 wavelength converter) were modeled in the 453 previously discussed. As discussed in [RFC6163] the constraints on 454 an electro-optical resource can be modeled in terms of input 455 constraints, processing capabilities, and output constraints: 457 ::= 459 [] 461 [] 463 [] 465 Where is a list of resource block identifiers 466 with the same characteristics. If this set is missing the 467 constraints are applied to the entire network element. 469 The are signal compatibility based constraints 470 and/or shared access constraint indication. The details of these 471 constraints are defined in section 5.3. 473 ::= 475 [] 477 [] 479 The are important operations that the 480 resource (or network element) can perform on the signal. The details 481 of these capabilities are defined in section 5.3. 483 ::= [] 485 [] 487 [] 489 [] 491 The are either restrictions on the properties of 492 the signal leaving the block, options concerning the signal 493 properties when leaving the resource or shared fiber output 494 constraint indication. 496 := 498 [] 500 [] 502 5.3. Compatibility and Capability Details 504 5.3.1. Shared Input or Output Indication 506 As discussed in the previous section and shown in Figure 2 the input 507 or output access to a resource block may be via a shared fiber. The 508 and elements are indicators for this 509 condition with respect to the block being described. 511 5.3.2. Optical Interface Class List 513 ::= ... 515 The Optical Interface Class is a unique number that identifies 516 all information related to optical characteristics of a physical 517 interface. The class may include other optical parameters 518 related to other interface properties. A class always includes 519 signal compatibility information. 521 The content of each class is out of the scope of this document 522 and can be defined by other entities (e.g. ITU, optical 523 equipment vendors, etc.). 525 Since even current implementation of physical interfaces may 526 support different optical characteristics, a single interface may 527 support multiple interface classes. Which optical interface 528 class is used among all the ones available for an interface is 529 out of the scope of this document but is an output of the RWA 530 process. 532 5.3.3. Acceptable Client Signal List 534 The list is simply: 536 ::=[]... 538 Where the Generalized Protocol Identifiers (G-PID) object 539 represents one of the IETF standardized G-PID values as defined 540 in [RFC3471] and [RFC4328]. 542 5.3.4. Processing Capability List 544 The ProcessingCapabilities were defined in Section 5.2. 546 The processing capability list sub-TLV is a list of processing 547 functions that the WSON network element (NE) can perform on the 548 signal including: 550 1. Number of Resources within the block 552 2. Regeneration capability 554 3. Fault and performance monitoring 556 4. Vendor Specific capability 558 Note that the code points for Fault and performance monitoring and 559 vendor specific capability are subject to further study. 561 6. Link Information (General) 563 MPLS-TE routing protocol extensions for OSPF and IS-IS [RFC3630], 564 [RFC5305] along with GMPLS routing protocol extensions for OSPF and 565 IS-IS [RFC4203, RFC5307] provide the bulk of the relatively static 566 link information needed by the RWA process. However, WSON networks 567 bring in additional link related constraints. These stem from WDM 568 line system characterization, laser transmitter tuning restrictions, 569 and switching subsystem port wavelength constraints, e.g., colored 570 ROADM drop ports. 572 In the following summarize both information from existing GMPLS 573 route protocols and new information that maybe needed by the RWA 574 process. 576 ::= 578 [] 580 [] 582 [] 584 [...] 586 [] 588 [...] 590 Note that these additional link characteristics only applies to line 591 side ports of WDM system or add/drop ports pertaining to Resource 592 Pool (e.g., Regenerator or Wavelength Converter Pool). The 593 advertisement of input/output tributary ports is not intended here. 595 6.1. Administrative Group 597 Administrative Group: Defined in [RFC3630] and extended for MPLS-TE 598 [RFC7308]. Each set bit corresponds to one administrative group 599 assigned to the interface. A link may belong to multiple groups. 600 This is a configured quantity and can be used to influence routing 601 decisions. 603 6.2. Interface Switching Capability Descriptor 605 InterfaceSwCapDesc: Defined in [RFC4202], lets us know the different 606 switching capabilities on this GMPLS interface. In both [RFC4203] 607 and [RFC5307] this information gets combined with the maximum LSP 608 bandwidth that can be used on this link at eight different priority 609 levels. 611 6.3. Link Protection Type (for this link) 613 Protection: Defined in [RFC4202] and implemented in [RFC4203, 614 RFC5307]. Used to indicate what protection, if any, is guarding this 615 link. 617 6.4. Shared Risk Link Group Information 619 SRLG: Defined in [RFC4202] and implemented in [RFC4203, RFC5307]. 620 This allows for the grouping of links into shared risk groups, i.e., 621 those links that are likely, for some reason, to fail at the same 622 time. 624 6.5. Traffic Engineering Metric 626 TrafficEngineeringMetric: Defined in [RFC3630] and [RFC5305]. This 627 allows for the identification of a data channel link metric value 628 for traffic engineering that is separate from the metric used for 629 path cost computation of the control plane. 631 Note that multiple "link metric values" could find use in optical 632 networks, however it would be more useful to the RWA process to 633 assign these specific meanings such as link mile metric, or 634 probability of failure metric, etc... 636 6.6. Port Label Restrictions 638 Port label restrictions could be applied generally to any label 639 types in GMPLS by adding new kinds of restrictions. Wavelength is a 640 type of label. 642 Port label (wavelength) restrictions (PortLabelRestriction) model 643 the label (wavelength) restrictions that the link and various 644 optical devices such as OXCs, ROADMs, and waveband multiplexers may 645 impose on a port. These restrictions tell us what wavelength may or 646 may not be used on a link and are relatively static. This plays an 647 important role in fully characterizing a WSON switching device 648 [Switch]. Port wavelength restrictions are specified relative to the 649 port in general or to a specific connectivity matrix (section 4.1. 650 Reference [Switch] gives an example where both switch and fixed 651 connectivity matrices are used and both types of constraints occur 652 on the same port. 654 ::= 656 658 660 ::= 662 | 664 | 666