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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) No issues found here. Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Network work group Fatai Zhang 2 Internet Draft Young Lee 3 Intended status: Standards Track Jianrui Han 4 Huawei 5 G. Bernstein 6 Grotto Networking 7 Yunbin Xu 8 CATR 10 Expires: August 11, 2015 February 11, 2015 12 OSPF-TE Extensions for General Network Element Constraints 14 draft-ietf-ccamp-gmpls-general-constraints-ospf-te-09.txt 16 Status of this Memo 18 This Internet-Draft is submitted to IETF in full conformance with 19 the provisions of BCP 78 and BCP 79. 21 Internet-Drafts are working documents of the Internet Engineering 22 Task Force (IETF), its areas, and its working groups. Note that 23 other groups may also distribute working documents as Internet- 24 Drafts. 26 Internet-Drafts are draft documents valid for a maximum of six 27 months and may be updated, replaced, or obsoleted by other documents 28 at any time. It is inappropriate to use Internet-Drafts as 29 reference material or to cite them other than as "work in progress." 31 The list of current Internet-Drafts can be accessed at 32 http://www.ietf.org/ietf/1id-abstracts.txt 34 The list of Internet-Draft Shadow Directories can be accessed at 35 http://www.ietf.org/shadow.html 37 This Internet-Draft will expire on August 11, 2015. 39 Copyright Notice 41 Copyright (c) 2015 IETF Trust and the persons identified as the 42 document authors. All rights reserved. 44 This document is subject to BCP 78 and the IETF Trust's Legal 45 Provisions Relating to IETF Documents 46 (http://trustee.ietf.org/license-info) in effect on the date of 47 publication of this document. Please review these documents 48 carefully, as they describe your rights and restrictions with 49 respect to this document. Code Components extracted from this 50 document must include Simplified BSD License text as described in 51 Section 4.e of the Trust Legal Provisions and are provided without 52 warranty as described in the Simplified BSD License. 54 Abstract 56 Generalized Multiprotocol Label Switching (GMPLS) can be used to 57 control a wide variety of technologies including packet switching 58 (e.g., MPLS), time-division (e.g., SONET/SDH, Optical Transport 59 Network (OTN)), wavelength (lambdas), and spatial switching (e.g., 60 incoming port or fiber to outgoing port or fiber). In some of these 61 technologies, network elements and links may impose additional 62 routing constraints such as asymmetric switch connectivity, non- 63 local label assignment, and label range limitations on links. This 64 document describes Open Shortest Path First (OSPF) routing protocol 65 extensions to support these kinds of constraints under the control 66 of GMPLS. 68 Conventions used in this document 70 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 71 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 72 document are to be interpreted as described in RFC-2119 [RFC2119]. 74 Table of Contents 76 1. Introduction...................................................3 77 2. Node Information...............................................4 78 2.1. Connectivity Matrix.......................................4 79 3. Link Information...............................................4 80 3.1. Port Label Restrictions...................................5 81 4. Routing Procedures.............................................5 82 5. Scalability and Timeliness.....................................6 83 5.1. Different Sub-TLVs into Multiple LSAs.....................6 84 5.2. Decomposing a Connectivity Matrix into Multiple Matrices..7 85 6. Security Considerations........................................7 86 7. Manageability..................................................8 87 8. IANA Considerations............................................8 88 8.1. Node Information..........................................8 89 8.2. Link Information..........................................9 90 9. References.....................................................9 91 9.1. Normative References......................................9 92 9.2. Informative References...................................10 93 10. Authors' Addresses ...........................................10 94 Acknowledgment...................................................12 96 1. Introduction 98 Some data plane technologies that require the use of a GMPLS control 99 plane impose additional constraints on switching capability and 100 label assignment. In addition, some of these technologies should be 101 capable of performing non-local label assignment based on the nature 102 of the technology, e.g., wavelength continuity constraint in 103 Wavelength Switched Optical Network (WSON) [RFC6163]. Such 104 constraints can lead to the requirement for link by link label 105 availability in path computation and label assignment. 107 [GEN-Encode] provides efficient encodings of information needed by 108 the routing and label assignment process in technologies such as 109 WSON and are potentially applicable to a wider range of 110 technologies. The encoding provided in [GEN-Encode] is protocol- 111 neutral and can be used in routing, signaling and/or Path 112 Computation Element communication protocol extensions. 114 This document defines extensions to the OSPF routing protocol based 115 on [GEN-Encode] to enhance the Traffic Engineering (TE) properties 116 of GMPLS TE which are defined in [RFC3630], [RFC4202], and [RFC4203]. 117 The enhancements to the TE properties of GMPLS TE links can be 118 advertised in OSPF TE LSAs. The TE LSA, which is an opaque LSA with 119 area flooding scope [RFC3630], has only one top-level 120 Type/Length/Value (TLV) triplet and has one or more nested sub-TLVs 121 for extensibility. The top-level TLV can take one of three values (1) 122 Router Address [RFC3630], (2) Link [RFC3630], (3) Node Attribute 123 [RFC5786]. In this document, we enhance the sub-TLVs for the Link 124 TLV in support of the general network element constraints under the 125 control of GMPLS. 127 The detailed encoding of OSPF extensions are not defined in this 128 document. [GEN-Encode] provides encoding details. 130 2. Node Information 132 According to [GEN-Encode], the additional node information 133 representing node switching asymmetry constraints includes Node ID 134 and connectivity matrix. Except for the Node ID, which should comply 135 with Routing Address described in [RFC3630], the other pieces of 136 information are defined in this document. 138 Per [GEN-Encode], this document defines the Connectivity Matrix Sub- 139 TLV of the Node Attribute TLV defined in [RFC5786]. The new Sub-TLV 140 has Type TBD1 (to be assigned by IANA). 142 In some specific technologies, e.g., WSON networks, the Connectivity 143 Matrix sub-TLV may be optional, which depends on the control plane 144 implementations. Usually, for example, in WSON networks, 145 Connectivity Matrix sub-TLV may be advertised in the LSAs since WSON 146 switches are currently asymmetric. If no Connectivity Matrix sub-TLV 147 is included, it is assumed that the switches support symmetric 148 switching. 150 2.1. Connectivity Matrix 152 If the switching devices supporting certain data plane technology is 153 asymmetric, it is necessary to identify which input ports and labels 154 can be switched to some specific labels on a specific output port. 156 The Connectivity Matrix is used to identify these restrictions, 157 which can represent either the potential connectivity matrix for 158 asymmetric switches (e.g., ROADMs and such) or fixed connectivity 159 for an asymmetric device such as a multiplexer as defined in [WSON- 160 Info]. 162 The Connectivity Matrix is a sub-TLV of the Node Attribute TLV. The 163 length is the length of value field in octets. The meaning and 164 format of this sub-TLV value field are defined in Section 2.1 of 165 [GEN-Encode]. One sub-TLV contains one matrix. The Connectivity 166 Matrix sub-TLV may occur more than once to contain multiple matrices 167 within the Node Attribute TLV. In addition a large connectivity 168 matrix can be decomposed into smaller sub-matrices for transmission 169 in multiple LSAs as described in Section 5. 171 3. Link Information 173 The most common link sub-TLVs nested in the top-level link TLV are 174 already defined in [RFC3630], [RFC4203]. For example, Link ID, 175 Administrative Group, Interface Switching Capability Descriptor 176 (ISCD), Link Protection Type, Shared Risk Link Group Information 177 (SRLG), and Traffic Engineering Metric are among the typical link 178 sub-TLVs. 180 Per [GEN-Encode], this document defines the Port Label Restrictions 181 Sub-TLV of the Link TLV defined in [RFC3630]. The new Sub-TLV has 182 Type TBD2 (to be assigned by IANA). 184 Generally all the sub-TLVs above are optional, which depends on the 185 control plane implementations. The Port Label Restrictions sub-TLV 186 will not be advertised when there are no restrictions on label 187 assignment. 189 3.1. Port Label Restrictions 191 Port label restrictions describe the label restrictions that the 192 network element (node) and link may impose on a port. These 193 restrictions represent what labels may or may not be used on a link 194 and are intended to be relatively static. For increased modeling 195 flexibility, port label restrictions may be specified relative to 196 the port in general or to a specific connectivity matrix. 198 For example, the Port Label Restrictions describes the wavelength 199 restrictions that the link and various optical devices such as OXCs, 200 ROADMs, and waveband multiplexers may impose on a port in WSON. 201 These restrictions represent what wavelength may or may not be used 202 on a link and are relatively static. The detailed information about 203 port label restrictions is described in [WSON-Info]. 205 The Port Label Restrictions sub-TLV is a sub-TLV of the Link TLV. 206 The length is the length of value field in octets. The meaning and 207 format of this sub-TLV value field are defined in Section 2.2 of 208 [GEN-Encode]. The Port Label Restrictions sub-TLV may occur more 209 than once to specify a complex port constraint within the link TLV. 211 4. Routing Procedures 213 All the sub-TLVs are nested in top-level TLV(s) and contained in 214 Opaque LSAs. The flooding rules of Opaque LSAs are specified in 215 [RFC2328], [RFC5250], [RFC3630], and [RFC4203]. 217 Considering the routing scalability issues in some cases, the 218 routing protocol should be capable of supporting the separation of 219 dynamic information from relatively static information to avoid 220 unnecessary updates of static information when dynamic information 221 is changed. A standards-compliant approach is to separate the 222 dynamic information sub-TLVs from the static information sub-TLVs, 223 each nested in a separate top-level TLV ([RFC3630 and RFC5876]), and 224 advertise them in the separate OSPF TE LSAs. 226 For node information, since the Connectivity Matrix information is 227 static, the LSA containing the Node Attribute TLV can be updated 228 with a lower frequency to avoid unnecessary updates. 230 For link information, a mechanism MAY be applied such that static 231 information and dynamic information of one TE link are contained in 232 separate Opaque LSAs. For example, the Port Label Restrictions 233 information sub-TLV could be nested in separate top level link TLVs 234 and advertised in the separate LSAs. 236 As with other TE information, an implementation typically takes 237 measures to avoid rapid and frequent updates of routing information 238 that could cause the routing network to become swamped. See 239 [RFC3630] Section 3 for related details. 241 5. Scalability and Timeliness 243 This document has defined two sub-TLVs for describing generic 244 routing contraints. The examples given in [GEN-Encode] show that 245 very large systems, in terms of label count or ports, can be very 246 efficiently encoded. However there has been concern expressed that 247 some possible systems may produce LSAs that exceed the IP Maximum 248 Transmission Unit (MTU) and that methods be given to allow for the 249 splitting of general constraint LSAs into smaller LSAs that are 250 under the MTU limit. This section presents a set of techniques that 251 can be used for this purpose. 253 5.1. Different Sub-TLVs into Multiple LSAs 255 Two sub-TLVs are defined in this document: 257 1. Connectivity Matrix (Node Attribute TLV) 258 2. Port Label Restrictions (Link TLV) 260 The Connectivity Matrix can be carried in the Node Attribute TLV as 261 defined in [RFC5786] while the Port Label Restrictions can be 262 carried in an Link TLV of which there can be at most one in an LSA 263 as defined in [RFC3630]. Note that the Port Label Restrictions are 264 relatively static, i.e., only would change with hardware changes or 265 significant system reconfiguration. 267 5.2. Decomposing a Connectivity Matrix into Multiple Matrices 269 In the highly unlikely event that a Connectivity Matrix sub-TLV by 270 itself would result in an LSA exceeding the MTU, a single large 271 matrix can be decomposed into sub-matrices. Per [GEN-Encode] a 272 connectivity matrix just consists of pairs of input and output ports 273 that can reach each other and hence such this decomposition would be 274 straightforward. Each of these sub-matrices would get a unique 275 matrix identifier per [GEN-Encode]. 277 From the point of view of a path computation process, prior to 278 receiving an LSA with a Connectivity Matrix sub-TLV, no connectivity 279 restrictions are assumed, i.e., the standard GMPLS assumption of any 280 port to any port reachability holds. Once a Connectivity Matrix sub- 281 TLV is received then path computation would know that connectivity 282 is restricted and use the information from all Connectivity Matrix 283 sub-TLVs received to understand the complete connectivity potential 284 of the system. Prior to receiving any Connectivity Matrix sub-TLVs 285 path computation may compute a path through the system when in fact 286 no path exists. In between the reception of an additional 287 Connectivity Matrix sub-TLV path computation may not be able to find 288 a path through the system when one actually exists. Both cases are 289 currently encountered and handled with existing GMPLS mechanisms. 290 Due to the reliability mechanisms in OSPF the phenomena of late or 291 missing Connectivity Matrix sub-TLVs would be relatively rare. 293 In case where the new sub-TLVs or their attendant encodings are 294 malformed, the proper action would be to log the problem and ignore 295 just the sub-TLVs in GMPLS path computations rather than ignoring 296 the entire LSA. 298 6. Security Considerations 300 This document does not introduce any further security issues other 301 than those discussed in [RFC3630], [RFC4203], and [RFC5250]. 303 For general security aspects relevant to Generalized Multiprotocol 304 Label Switching (GMPLS)-controlled networks, please refer to 305 [RFC5920]. 307 7. Manageability 309 No existing management tools handle the additional TE parameters as 310 defined in this document and distributed in OSPF-TE. The existing 311 MIB module contained in [RFC6825] allows the TE information 312 distributed by OSPF-TE to be read from a network node: this MIB 313 module could be augmented (possibly by a sparse augmentation) to 314 report this new information. 316 The current environment in the IETF favors NETCONF [RFC6241] and 317 YANG [RFC6020] over SNMP and MIB modules. Work is in progress in 318 the TEAS working group to develop a YANG module to represent the 319 generic TE information that may be present in a Traffic Engineering 320 Database (TED). This model may be extended to handle the additional 321 information described in this document to allow that information to 322 be read from network devices or exchanged between consumers of the 323 TED. Furthermore, links state export using BGP [BGP-LS] enables the 324 export of TE information from a network using BGP. Work could 325 realistically be done to extend BGP-LS to also carry the information 326 defined in this document. 328 It is not envisaged that the extensions defined in this document 329 will place substantial additional requirements on Operations, 330 Management, and Administration (OAM) mechanisms currently used to 331 diagnose and debug OSPF systems. However, tools that examine the 332 contents of opaque LSAs will need to be enhanced to handle these new 333 sub-TLVs. 335 8. IANA Considerations 337 IANA is requested to allocate new sub-TLVs as defined in Sections 2 338 and 3 as follows: 340 8.1. Node Information 342 IANA maintains the "Open Shortest Path First (OSPF) Traffic 343 Engineering TLVs" registry with a sub-registry called "Types for 344 sub-TLVs of TE Node Attribute TLV". IANA is requested to assign a 345 new code point as follows: 347 Type | Sub-TLV | Reference 348 -------+-------------------------------+------------ 349 TBD1 | Connectivity Matrix sub-TLV | [This.I-D] 351 8.2. Link Information 353 IANA maintains the "Open Shortest Path First (OSPF) Traffic 354 Engineering TLVs" registry with a sub-registry called "Types for 355 sub-LVs of TE Link TLV". IANA is requested to assign a new code 356 point as follows: 358 Type | Sub-TLV | Reference 359 -------+-----------------------------------+------------ 360 TBD2 | Port Label Restrictions sub-TLV | [This.I-D] 362 9. References 364 9.1. Normative References 366 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 367 Requirement Levels", BCP 14, RFC 2119, March 1997. 369 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998. 371 [RFC3630] Katz, D., Kompella, K., and Yeung, D., "Traffic 372 Engineering (TE) Extensions to OSPF Version 2", RFC 3630, 373 September 2003. 375 [RFC4202] Kompella, K., Ed., and Y. Rekhter, Ed., "Routing 376 Extensions in Support of Generalized Multi-Protocol Label 377 Switching (GMPLS)", RFC 4202, October 2005 379 [RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions 380 in Support of Generalized Multi-Protocol Label Switching 381 (GMPLS)", RFC 4203, October 2005. 383 [RFC5250] L. Berger, I. Bryskin, A. Zinin, R. Coltun "The OSPF 384 Opaque LSA Option", RFC 5250, July 2008. 386 [RFC5786] R. Aggarwal and K. Kompella,"Advertising a Router's Local 387 Addresses in OSPF Traffic Engineering (TE) Extensions", 388 RFC 5786, March 2010. 390 [GEN-Encode] G. Bernstein, Y. Lee, D. Li, W. Imajuku, " General 391 Network Element Constraint Encoding for GMPLS Controlled 392 Networks", work in progress: draft-ietf-ccamp-general- 393 constraint-encode. 395 9.2. Informative References 397 [RFC6020] M. Bjorklund, Ed., "YANG - A Data Modeling Language for 398 the Network Configuration Protocol (NETCONF)", RFC 6020, 399 October 2010. 401 [RFC6163] Y. Lee, G. Bernstein, W. Imajuku, "Framework for GMPLS and 402 PCE Control of Wavelength Switched Optical Networks 403 (WSON)", RFC 6163, February 2011. 405 [RFC6241] R. Enns, Ed., M. Bjorklund, Ed., Schoenwaelder, Ed., A. 406 Bierman, Ed., "Network Configuration Protocol (NETCONF)", 407 RFC 6241, June 2011. 409 [RFC6825] M. Miyazawa, T. Otani, K. Kumaki, T. Nadeau, "Traffic 410 Engineering Database Management Information Base in 411 Support of MPLS-TE/GMPLS", RFC 6825, January 2013. 413 [WSON-Info] Y. Lee, G. Bernstein, D. Li, W. Imajuku, "Routing and 414 Wavelength Assignment Information Model for Wavelength 415 Switched Optical Networks", work in progress: draft-ietf- 416 ccamp-rwa-info. 418 [RFC5920] L. Fang, Ed., "Security Framework for MPLS and GMPLS 419 Networks", RFC 5920, July 2010. 421 [BGP-LS] H. Gredler, J. Medved, S. Previdi, A. Farrel, S. Ray, 422 "North-Bound Distribution of Link-State and TE Information 423 using BGP", work in progress: draft-ietf-idr-ls- 424 distribution. 426 10. Contributors 428 Guoying Zhang 429 China Academy of Telecommunication Research of MII 430 11 Yue Tan Nan Jie Beijing, P.R.China 431 Phone: +86-10-68094272 432 Email: zhangguoying@mail.ritt.com.cn 434 Dan Li 435 Huawei Technologies Co., Ltd. 436 F3-5-B R&D Center, Huawei Base 437 Bantian, Longgang District 438 Shenzhen 518129 P.R.China 440 Phone: +86-755-28973237 441 Email: danli@huawei.com 443 Ming Chen 444 European Research Center 445 Huawei Technologies 446 Riesstr. 25, 80992 Munchen, Germany 448 Phone: 0049-89158834072 449 Email: minc@huawei.com 451 Yabin Ye 452 European Research Center 453 Huawei Technologies 454 Riesstr. 25, 80992 Munchen, Germany 456 Phone: 0049-89158834074 457 Email: yabin.ye@huawei.com 459 Authors' Addresses 461 Fatai Zhang 462 Huawei Technologies 463 F3-5-B R&D Center, Huawei Base 464 Bantian, Longgang District 465 Shenzhen 518129 P.R.China 467 Phone: +86-755-28972912 468 Email: zhangfatai@huawei.com 470 Young Lee 471 Huawei Technologies 472 5360 Legacy Drive, Building 3 473 Plano, TX 75023 474 USA 475 Phone: (469)277-5838 476 Email: leeyoung@huawei.com 478 Jianrui Han 479 Huawei Technologies Co., Ltd. 480 F3-5-B R&D Center, Huawei Base 481 Bantian, Longgang District 482 Shenzhen 518129 P.R.China 484 Phone: +86-755-28977943 485 Email: hanjianrui@huawei.com 487 Greg Bernstein 488 Grotto Networking 489 Fremont CA, USA 491 Phone: (510) 573-2237 492 Email: gregb@grotto-networking.com 494 Yunbin Xu 495 China Academy of Telecommunication Research of MII 496 11 Yue Tan Nan Jie Beijing, P.R.China 497 Phone: +86-10-68094134 498 Email: xuyunbin@mail.ritt.com.cn 500 Acknowledgment 502 We thank Ming Chen and Yabin Ye from DICONNET Project who provided 503 valuable information for this document. 505 Intellectual Property 507 The IETF Trust takes no position regarding the validity or scope of 508 any Intellectual Property Rights or other rights that might be 509 claimed to pertain to the implementation or use of the technology 510 described in any IETF Document or the extent to which any license 511 under such rights might or might not be available; nor does it 512 represent that it has made any independent effort to identify any 513 such rights. 515 Copies of Intellectual Property disclosures made to the IETF 516 Secretariat and any assurances of licenses to be made available, or 517 the result of an attempt made to obtain a general license or 518 permission for the use of such proprietary rights by implementers or 519 users of this specification can be obtained from the IETF on-line 520 IPR repository at http://www.ietf.org/ipr 522 The IETF invites any interested party to bring to its attention any 523 copyrights, patents or patent applications, or other proprietary 524 rights that may cover technology that may be required to implement 525 any standard or specification contained in an IETF Document. 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