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Papadimitriou, ed. 7 Alcatel-Lucent 8 October 9, 2012 10 ASON Routing for OSPFv2 Protocols 11 draft-ietf-ccamp-rfc5787bis-06.txt 13 Status of this Memo 15 This Internet-Draft is submitted to IETF in full conformance with the 16 provisions of BCP 78 and BCP 79. 18 Internet-Drafts are working documents of the Internet Engineering 19 Task Force (IETF), its areas, and its working groups. Note that 20 other groups may also distribute working documents as 21 Internet-Drafts. 23 Internet-Drafts are draft documents valid for a maximum of six months 24 and may be updated, replaced, or obsoleted by other documents at any 25 time. It is inappropriate to use Internet-Drafts as reference 26 material or to cite them other than as "work in progress." 28 The list of current Internet-Drafts can be accessed at 29 http://www.ietf.org/1id-abstracts.html 31 The list of Internet-Draft Shadow Directories can be accessed at 32 http://www.ietf.org/shadow.html 34 Copyright and License Notice 36 Copyright (c) 2012 IETF Trust and the persons identified as the 37 document authors. All rights reserved. 39 This document is subject to BCP 78 and the IETF Trust's Legal 40 Provisions Relating to IETF Documents 41 (http://trustee.ietf.org/license-info) in effect on the date of 42 publication of this document. Please review these documents 43 carefully, as they describe your rights and restrictions with respect 44 to this document. Code Components extracted from this document must 45 include Simplified BSD License text as described in Section 4.e of 46 the Trust Legal Provisions and are provided without warranty as 47 described in the Simplified BSD License. 49 Abstract 51 The ITU-T has defined an architecture and requirements for operating 52 an Automatically Switched Optical Network (ASON). 54 The Generalized Multiprotocol Label Switching (GMPLS) protocol suite 55 is designed to provide a control plane for a range of network 56 technologies including optical networks such as time division 57 multiplexing (TDM) networks including SONET/SDH and Optical Transport 58 Networks (OTNs), and lambda switching optical networks. 60 The requirements for GMPLS routing to satisfy the requirements of 61 ASON routing, and an evaluation of existing GMPLS routing protocols 62 are provided in other documents. This document defines extensions to 63 the OSPFv2 Link State Routing Protocol to meet the requirements for 64 routing in an ASON. 66 Note that this work is scoped to the requirements and evaluation 67 expressed in RFC 4258 and RFC 4652 and the ITU-T Recommendations 68 current when those documents were written. Future extensions of 69 revisions of this work may be necessary if the ITU-T Recommendations 70 are revised or if new requirements are introduced into a revision of 71 RFC 4258. This document obsoletes RFC 5787 and updates RFC 5786. 73 Table of Contents 75 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 76 1.1. Conventions Used in This Document . . . . . . . . . . . . 5 77 2. Routing Areas, OSPF Areas, and Protocol Instances . . . . . . 5 78 3. Terminology and Identification . . . . . . . . . . . . . . . . 6 79 4. Reachability . . . . . . . . . . . . . . . . . . . . . . . . . 7 80 5. Link Attribute . . . . . . . . . . . . . . . . . . . . . . . . 7 81 5.1. Local Adaptation . . . . . . . . . . . . . . . . . . . . . 8 82 5.2. Bandwidth Accounting . . . . . . . . . . . . . . . . . . . 8 83 6. Routing Information Scope . . . . . . . . . . . . . . . . . . 9 84 6.1. Link Advertisement (Local and Remote TE Router ID 85 Sub-TLV) . . . . . . . . . . . . . . . . . . . . . . . . . 9 86 6.2. Reachability Advertisement (Local TE Router ID sub-TLV) . 10 87 7. Routing Information Dissemination . . . . . . . . . . . . . . 11 88 7.1 Import/Export Rules . . . . . . . . . . . . . . . . . . . . 11 89 7.2 Loop Prevention . . . . . . . . . . . . . . . . . . . . . . 12 90 7.2.1 Inter-RA Export Upward/Downward Sub-TLVs . . . . . . . 12 91 7.2.2 Inter-RA Export Upward/Downward Sub-TLV Processing . . 13 92 8. OSPFv2 Scalability . . . . . . . . . . . . . . . . . . . . . . 14 93 9. Security Considerations . . . . . . . . . . . . . . . . . . . 14 94 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 95 10.1. Sub-TLVs of the Link TLV . . . . . . . . . . . . . . . . 15 96 10.2. Sub-TLVs of the Node Attribute TLV . . . . . . . . . . . 15 97 10.3. Sub-TLVs of the Router Address TLV . . . . . . . . . . . 16 98 11. Management Considerations . . . . . . . . . . . . . . . . . 17 99 11.1. Routing Area (RA) Isolation . . . . . . . . . . . . . . . 17 100 11.2 Routing Area (RA) Topology/Configuration Changes . . . . . 17 101 12. Comparison to Requirements in RFC 4258 . . . . . . . . . . . 17 102 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 103 13.1. Normative References . . . . . . . . . . . . . . . . . . 23 104 13.2. Informative References . . . . . . . . . . . . . . . . . 24 105 14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25 106 14.1 RFC 5787 Acknowledgements . . . . . . . . . . . . . . . . . 25 107 Appendix A. ASON Terminology . . . . . . . . . . . . . . . . . . 26 108 Appendix B. ASON Routing Terminology . . . . . . . . . . . . . . 27 109 Appendix C. Changes from RFC 5787 . . . . . . . . . . . . . . . . 28 110 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29 112 1. Introduction 114 The Generalized Multiprotocol Label Switching (GMPLS) [RFC3945] 115 protocol suite is designed to provide a control plane for a range of 116 network technologies including optical networks such as time division 117 multiplexing (TDM) networks including SONET/SDH and Optical Transport 118 Networks (OTNs), and lambda switching optical networks. 120 The ITU-T defines the architecture of the Automatically Switched 121 Optical Network (ASON) in [G.8080]. 123 [RFC4258] describes the routing requirements for the GMPLS suite of 124 routing protocols to support the capabilities and functionality of 125 ASON control planes identified in [G.7715] and in [G.7715.1]. 127 [RFC4652] evaluates the IETF Link State routing protocols against the 128 requirements identified in [RFC4258]. Section 7.1 of [RFC4652] 129 summarizes the capabilities to be provided by OSPFv2 [RFC2328] in 130 support of ASON routing. This document describes the OSPFv2 131 specifics for ASON routing. 133 Multi-layer transport networks are constructed from multiple networks 134 of different technologies operating in a client-server relationship. 135 The ASON routing model includes the definition of routing levels that 136 provide scaling and confidentiality benefits. In multi-level 137 routing, domains called routing areas (RAs) are arranged in a 138 hierarchical relationship. Note that as described in [RFC4652], 139 there is no implied relationship between multi-layer transport 140 networks and multi-level routing. The multi-level routing mechanisms 141 described in this document work for both single-layer and multi-layer 142 networks. 144 Implementations may support a hierarchical routing topology (multi- 145 level) for multiple transport network layers and/or a hierarchical 146 routing topology for a single transport network layer. 148 This document describes the processing of the generic (technology- 149 independent) link attributes that are defined in [RFC3630], 150 [RFC4202], and [RFC4203] and that are extended in this document. As 151 described in Section 5.2, technology-specific traffic engineering 152 attributes and their processing may be defined in other documents 153 that complement this document. 155 Note that this work is scoped to the requirements and evaluation 156 expressed in [RFC4258] and [RFC4652] and the ITU-T Recommendations 157 current when those documents were written. Future extensions of 158 revisions of this work may be necessary if the ITU-T Recommendations 159 are revised or if new requirements are introduced into a revision of 161 [RFC4258]. 163 1.1. Conventions Used in This Document 165 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 166 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 167 document are to be interpreted as described in RFC 2119 [RFC2119]. 169 The reader is assumed to be familiar with the terminology and 170 requirements developed in [RFC4258] and the evaluation outcomes 171 described in [RFC4652]. 173 General ASON terminology is provided in Appendix A. ASON routing 174 terminology is described in Appendix B. 176 2. Routing Areas, OSPF Areas, and Protocol Instances 178 An ASON routing area (RA) represents a partition of the transport 179 plane, and its identifier is used within the control plane as the 180 representation of this partition. 182 RAs are hierarchically contained: a higher-level (parent) RA contains 183 lower-level (child) RAs that in turn MAY also contain RAs. Thus, RAs 184 contain RAs that recursively define successive hierarchical RA 185 levels. Routing information may be exchanged between levels of the 186 RA hierarchy, i.e., Level N+1 and N, where Level N represents the RAs 187 contained by Level N+1. The links connecting RAs may be viewed as 188 external links (inter-RA links), and the links representing 189 connectivity within an RA may be viewed as internal links (intra-RA 190 links). The external links to an RA at one level of the hierarchy 191 may be internal links in the parent RA. Intra-RA links of a child RA 192 MAY be hidden from the parent RA's view. [RFC4258] 194 An ASON RA can be mapped to an OSPF area, but the hierarchy of ASON 195 RA levels does not map to the hierarchy of OSPF areas. Instead, 196 successive hierarchical levels of RAs MUST be represented by separate 197 instances of the protocol. Thus, inter-level routing information 198 exchange (as described in Section 7) involves the export and import 199 of routing information between protocol instances. 201 An ASON RA may therefore be identified by the combination of its OSPF 202 instance identifier and its OSPF area identifier. With proper and 203 careful network-wide configuration, this can be achieved using just 204 the OSPF area identifier, and this process is RECOMMENDED in this 205 document. These concepts are discussed in Section 7. 207 A key ASON requirement is the support of multiple transport planes or 208 layers. Each transport node has associated topology (links and 209 reachability) which is used for ASON routing. 211 3. Terminology and Identification 213 This section describes the mapping of key ASON entities to OSPF 214 entities. Appendix A contains a complete glossary of ASON routing 215 terminology. 217 There are three categories of identifiers used for ASON routing 218 (G7715.1): transport plane names, control plane identifiers for 219 components, and Signaling Communications Network (SCN) addresses. 220 This section discusses the mapping between ASON routing identifiers 221 and corresponding identifiers defined for GMPLS routing, and how 222 these support the physical (or logical) separation of transport plane 223 entities and control plane components. GMPLS supports this 224 separation of identifiers and planes. 226 In the context of OSPF Traffic Engineering (TE), an ASON transport 227 node corresponds to a unique OSPF TE node. An OSPF TE node is 228 uniquely identified by the TE Router Address TLV [RFC3630]. In this 229 document, the TE Router Address is referred to as the TE Router ID. 230 In GMPLS, TE router addresses are advertised as reachable in both the 231 control and transport planes, see Section 4 below. Furthermore, the 232 TE Router ID should not be confused with the OSPF Router ID that 233 uniquely identifies an OSPF router within an OSPF routing domain 234 [RFC2328] and is in a name space for control plane components. 236 The Router Address top-level TLV definition, processing, and usage 237 are largely unchanged from [RFC3630]. This TLV specifies a stable 238 OSPF TE node IP address, i.e., the IP address is always reachable 239 when there is IP connectivity to the associated OSPF TE node. 241 ASON defines a Routing Controller (RC) as an entity that handles 242 (abstract) information needed for routing and the routing information 243 exchange with peering RCs by operating on the Routing Database (RDB). 244 ASON defines a Protocol Controller (PC) as an entity that handles 245 protocol-specific message exchanges according to the reference point 246 over which the information is exchanged (e.g., E-NNI, I-NNI), and 247 internal exchanges with the Routing Controller (RC) [RFC4258]. In 248 this document, an OSPF router advertising ASON TE topology 249 information will perform both the functions of the RC and PC. The 250 OSPF routing domain comprises the control plane and each OSPF router 251 is uniquely identified by its OSPF Router ID [RFC2328]. 253 4. Reachability 255 In ASON, reachability information describes the set of endpoints that 256 are reachable by the associated node in the transport plane. 257 Reachability information represents transport plane resources, e.g., 258 an optical cross-connect interface, and uses transport plane 259 identifiers. 261 In order to advertise blocks of reachable address prefixes, a 262 summarization mechanism is introduced that is based on the techniques 263 described in [RFC5786]. For ASON reachability advertisement, blocks 264 of reachable address prefixes are advertised together with the 265 associated transport plane node. The transport plane node is 266 identified in OSPF TE LSAs by its TE Router ID, as discussed in 267 section 6. 269 In order to support ASON reachability advertisement, the Node 270 Attribute TLV defined in [RFC5786] is used to advertise the 271 combination of a TE Router ID and its set of associated reachable 272 address prefixes. The Node Attribute TLV can contain the following 273 sub-TLVs: 275 - TE Router ID sub-TLV: Length: 4; Defined in Section 6.2 276 - Node IPv4 Local Address sub-TLV: Length: variable; [RFC5786] 277 - Node IPv6 Local Address sub-TLV: Length: variable; [RFC5786] 279 A router may support multiple transport nodes as discussed in section 280 6, and, as a result, may be required to advertise reachability 281 separately for each transport node. As a consequence, it MUST be 282 possible for the router to originate more than one TE LSA containing 283 the Node Attribute TLV when used for ASON reachability advertisement. 285 Hence, the Node Attribute TLV [RFC5786] advertisement rules are 286 relaxed. A Node Attribute TLV MAY appear in more than one TE LSA 287 originated by the RC when the RC is advertising reachability 288 information for a different transport node identified by the Local TE 289 Router Sub-TLV (refer to section 6.2). 291 As specified in [RFC3630], TE advertised router addresses are also 292 advertised as reachable in the control plane and are therefore also 293 valid identifiers in the ASON SCN name space. 295 5. Link Attribute 297 With the exception of local adaptation (described below), the mapping 298 of link attributes and characteristics to OSPF TE Link TLV Sub-TLVs 299 is unchanged [RFC4652]. OSPF TE Link TLV Sub-TLVs are described in 300 [RFC3630] and [RFC4203]. Advertisement of this information SHOULD be 301 supported on a per-layer basis, i.e., one TE LSA per unique switching 302 capability and bandwidth granularity combination. 304 5.1. Local Adaptation 306 Local adaptation is defined as a TE link attribute (i.e., sub-TLV) 307 that describes the cross/inter-layer relationships. 309 The Interface Switching Capability Descriptor (ISCD) TE Attribute 310 [RFC4202] identifies the ability of the TE link to support cross- 311 connection to another link within the same layer. When advertising 312 link adaptation, it also identifies the ability to use a locally 313 terminated connection that belongs to one layer as a data link for 314 another layer (adaptation capability). However, the information 315 associated with the ability to terminate connections within that 316 layer (referred to as the termination capability) is advertised with 317 the adaptation capability. 319 For instance, a link between two optical cross-connects will contain 320 at least one ISCD attribute describing the Lambda Switching Capable 321 (LSC) switching capability. Conversely, a link between an optical 322 cross-connect and an IP/MPLS Label Switching Router (LSR) will 323 contain at least two ISCD attributes, one for the description of the 324 LSC termination capability and one for the Packet Switching Capable 325 (PSC) adaptation capability. 327 In OSPFv2, the Interface Switching Capability Descriptor (ISCD) is a 328 sub-TLV (type 15) of the top-level Link TLV (type 2) [RFC4203]. The 329 adaptation and termination capabilities are advertised using two 330 separate ISCD sub-TLVs within the same top-level Link TLV. 332 An interface MAY have more than one ISCD sub-TLV, [RFC4202] and 333 [RFC4203]. Hence, the corresponding advertisements should not result 334 in any compatibility issues. 336 5.2. Bandwidth Accounting 338 GMPLS routing defines an Interface Switching Capability Descriptor 339 (ISCD) that provides, among other things, the quantities of the 340 maximum/minimum available bandwidth per priority for Label Switched 341 Path (LSPs). One or more ISCD sub-TLVs can be associated with an 342 interface, [RFC4202] and [RFC4203]. This information, combined with 343 the Unreserved Bandwidth Link TLV sub-TLV [RFC3630], provides the 344 basis for bandwidth accounting. 346 In the ASON context, additional information may be included when the 347 representation and information in the other advertised fields are not 348 sufficient for a specific technology, e.g., SDH. The definition of 349 technology-specific information elements is beyond the scope of this 350 document. Some technologies will not require additional information 351 beyond what is already defined in [RFC3630], [RFC4202], and 352 [RFC4203]. 354 6. Routing Information Scope 356 For ASON routing, the control plane component routing adjacency 357 topology (i.e., the associated Protocol Controller (PC) connectivity) 358 and the transport topology are not assumed to be congruent [RFC4258]. 359 Hence, a single OSPF router (i.e., the PC) MUST be able to advertise 360 on behalf of multiple transport layer nodes. The OSPF routers are 361 identified by OSPF Router ID and the transport nodes are identified 362 by TE Router ID. 364 The Router Address TLV [RFC3630] is used to advertise the TE Router 365 ID associated with the advertising Routing Controller (RC). TE Router 366 IDs for additional transport nodes are advertised through 367 specification of the Local TE Router Identifier in the Local and 368 Remote TE Router TE sub-TLV and the Local TE Router Identifier sub- 369 TLV described in the sections below. These Local TE Router 370 Identifiers are typically used as the local endpoints for TE Label 371 Switched Paths (LSPs) terminating on the associated transport node. 373 The use of multiple OSPF Routers to advertise TE information for the 374 same transport node is not considered a required use case and is not 375 discussed further in this document. 377 6.1. Link Advertisement (Local and Remote TE Router ID Sub-TLV) 379 When an OSPF Router advertises on behalf of multiple transport nodes, 380 the link end points cannot be automatically assigned to a single 381 transport node associated with the advertising router. In this case, 382 the local and remote transport nodes MUST be identified by TE router 383 ID to unambiguously specify the transport topology. 385 For this purpose, a new sub-TLV of the OSPFv2 TE LSA top-level Link 386 TLV is introduced that defines the Local and Remote TE Router ID. 388 The Type field of the Local and Remote TE Router ID sub-TLV is 389 assigned the value TBDx (see Section 10). The Length field takes the 390 value 8. The Value field of this sub-TLV contains 4 octets of the 391 Local TE Router Identifier followed by 4 octets of the Remote TE 392 Router Identifier. The value of the Local and Remote TE Router 393 Identifier SHOULD NOT be set to 0. 395 The format of the Local and Remote TE Router ID sub-TLV is: 397 0 1 2 3 398 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 399 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 400 | Type (TBDx) | Length (8) | 401 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 402 | Local TE Router Identifier | 403 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 404 | Remote TE Router Identifier | 405 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 407 This sub-TLV MUST be included as a sub-TLV of the top-level Link TLV 408 if the OSPF router is advertising on behalf of one or more transport 409 nodes having TE Router IDs different from the TE Router ID advertised 410 in the Router Address TLV. For consistency, this sub-TLV MUST be 411 included when OSPF is used for the advertisement of ASON information 412 as described herein. If it is not included in a Link TLV or a value 413 of 0 is specified for the Local or Remote TE Router Identifier, the 414 Link TLV will not be used for transport plane path computation. 415 Additionally, the condition SHOULD be logged for possible action by 416 the network operator. 418 Note: The Link ID sub-TLV identifies the other end of the link (i.e., 419 Router ID of the neighbor for point-to-point links) [RFC3630]. When 420 the Local and Remote TE Router ID Sub-TLV is present, it MUST be used 421 to identify local and remote transport node endpoints for the link 422 and the Link-ID sub-TLV MUST be ignored. In fact, when the Local and 423 Remote TE Router ID sub-TLV is specified, the Link-ID sub-TLV MAY be 424 omitted. The Local and Remote TE Router ID sub-TLV, if specified, 425 MUST only be specified once. If specified more than once, instances 426 other than the first will be ignored and condition SHOULD be logged 427 for possible action by the network operator. 429 6.2. Reachability Advertisement (Local TE Router ID sub-TLV) 431 When an OSPF router is advertising on behalf of multiple transport 432 nodes, the routing protocol MUST be able to associate the advertised 433 reachability information with the correct transport node. 435 For this purpose, a new sub-TLV of the OSPFv2 TE LSA top-level Node 436 Attribute TLV is introduced. This TLV associates the local prefixes 437 (see above) to a given transport node identified by TE Router ID. 439 The Type field of the Local TE Router ID sub-TLV is assigned the 440 value 5 (see Section 10). The Length field takes the value 4. The 441 Value field of this sub-TLV contains the Local TE Router Identifier 442 encoded over 4 octets. 444 The format of the Local TE Router ID sub-TLV is: 446 0 1 2 3 447 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 448 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 449 | Type (5) | Length (4) | 450 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 451 | Local TE Router Identifier | 452 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 454 This sub-TLV MUST be included as a sub-TLV of the top-level Node 455 Attribute TLV if the OSPF router is advertising on behalf of one or 456 more transport nodes having TE Router IDs different from the TE 457 Router ID advertised in the Router Address TLV. For consistency, 458 this sub-TLV MUST be included when OSPF is used for the advertisement 459 of ASON information as described herein. If it is not included in a 460 Node Attribute TLV or a value of 0 is specified for the Local TE 461 Router Identifier, the Note Attribute TLV will not be used for 462 determining ASON SCN reachability. Additionally, the condition 463 SHOULD be logged for possible action by the network operator. 465 7. Routing Information Dissemination 467 An ASON routing area (RA) represents a partition of the transport 468 plane, and its identifier is used within the control plane as the 469 representation of this partition. An RA may contain smaller RAs 470 inter-connected by links. ASON RA levels do not map directly to OSPF 471 areas. Rather, hierarchical levels of RAs are represented by separate 472 OSPF protocol instances. However, it is useful to align the RA 473 identifiers and area ID in order to facilitate isolation of RAs as 474 described in Section 11.1. 476 Routing controllers (RCs) supporting multiple RAs disseminate 477 information downward and upward in this ASON hierarchy. The vertical 478 routing information dissemination mechanisms described in this 479 section do not introduce or imply hierarchical OSPF areas. RCs 480 supporting RAs at multiple levels are structured as separate OSPF 481 instances with routing information exchange between levels described 482 by import and export rules between these instances. The functionality 483 described herein does not pertain to OSPF areas or OSPF Area Border 484 Router (ABR) functionality. 486 7.1 Import/Export Rules 488 RCs supporting RAs disseminate information upward and downward in the 489 hierarchy by importing/exporting routing information as TE LSAs. TE 490 LSAs are area-scoped opaque LSAs with opaque type 1 [RFC3630]. The 491 information that MAY be exchanged between adjacent levels includes 492 the Router Address, Link, and Node Attribute top-level TLVs. 494 The imported/exported routing information content MAY be transformed, 495 e.g., filtered or aggregated, as long as the resulting routing 496 information is consistent. In particular, when more than one RC is 497 bound to adjacent levels and both are allowed to import/export 498 routing information, it is expected that these transformations are 499 performed in a consistent manner. Definition of these policy-based 500 mechanisms are outside the scope of this document. 502 In practice, and in order to avoid scalability and processing 503 overhead, routing information imported/exported downward/upward in 504 the hierarchy is expected to include reachability information (see 505 Section 4) and, upon strict policy control, link topology 506 information. 508 7.2 Loop Prevention 510 When more than one RC is bound to an adjacent level of the ASON 511 hierarchy, and is configured to export routing information upward or 512 downward, a specific mechanism is required to avoid looping of 513 routing information. Looping is the re-advertisement of routing 514 information into an RA that had previously advertised that routing 515 information upward or downward into an upper or lower level RA in the 516 ASON hierarchy. For example, without loop prevention mechanisms, this 517 could happen when the RC advertising routing information downward in 518 the hierarchy is not the same one that advertises routing information 519 upward in the hierarchy. 521 7.2.1 Inter-RA Export Upward/Downward Sub-TLVs 523 The Inter-RA Export Sub-TLVs can be used to prevent the re- 524 advertisement of OSPF TE routing information into an RA which 525 previously advertised that information. The type value TBDz (see 526 Section 10) will indicate that the associated routing information has 527 been exported downward. The type value TBDy (see Section 10) will 528 indicate that the associated routing information has been exported 529 upward. While it is not required for routing information exported 530 downward, both Sub-TLVs will include the Routing Area (RA) ID from 531 which the routing information was exported. This RA is not 532 necessarily the RA originating the routing information but RA from 533 which the information was immediately exported. 535 These additional Sub-TLVs MAY be included in TE LSAs that include any 536 of the following top-level TLVs: 538 - Router Address top-level TLV 539 - Link top-level TLV 540 - Node Attribute top-level TLV 542 The Type field of the Inter-RA Export Upward and Inter-RA Export 543 Downward sub-TLVs are respectively assigned the values TBDy and TBDz 544 (see Section 10). The Length field in these Sub-TLVs takes the value 545 4. The Value field in these sub-TLVs contains the associated RA ID. 546 The RA ID value must be a unique identifier for the RA within the 547 ASON routing domain. 549 The format of the Inter-RA Export Upward and Inter-RA Export Downward 550 Sub-TLVs is graphically depicted below: 552 0 1 2 3 553 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 554 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 555 | Upward/Downward Type | Length (4) | 556 | (TBDy/TBDz) | | 557 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 558 | Associated RA ID | 559 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 561 7.2.2 Inter-RA Export Upward/Downward Sub-TLV Processing 563 TE LSAs MAY be imported or exported downward or upward in the ASON 564 routing hierarchy. The direction and advertising RA ID are advertised 565 in an Inter-RA Export Upward/Downward Sub-TLV. They MUST be retained 566 and advertised in the receiving RA with the associated routing 567 information. 569 When exporting routing information upward in the ASON routing 570 hierarchy, any information received from a level above, i.e., tagged 571 with an Inter-RA Export Downward Sub-TLV, MUST NOT be exported 572 upward. Since an RA at level N is contained by a single RA at level 573 N+1, this is the only checking that is necessary and the associated 574 RA ID is used solely for informational purposes. 576 When exporting routing information downward in the ASON routing 577 hierarchy, any information received from a level below, i.e., tagged 578 with an Inter-RA Export Upward Sub-TLV MUST NOT be exported downward 579 if the target RA ID matches the RA ID associated with the routing 580 information. This additional checking is required for routing 581 information exported downward since a single RA at level N+1 may 582 contain multiple RAs at level N in the ASON routing hierarchy. In 583 order words, routing information MUST NOT be exported downward into 584 the RA from which it was received. 586 8. OSPFv2 Scalability 588 The extensions described herein are only applicable to ASON routing 589 domains and it is not expected that the attendant reachability (see 590 Section 4) and link information will ever be combined with global 591 Internet or Layer 3 Virtual Private Network (VPN) routing. If there 592 were ever a requirement for a given RC to participate in both 593 domains, separate OSPFv2 instances would be utilized. However, in a 594 multi-level ASON hierarchy, the potential volume of information could 595 be quite large and the recommendations in this section MUST be 596 followed by RCs implementing this specification. 598 - Routing information exchange upward/downward in the hierarchy 599 between adjacent RAs MUST, by default, be limited to reachability 600 information. In addition, several transformations such as prefix 601 aggregation are RECOMMENDED to reduce the amount of information 602 imported/exported by a given RC when such transformations will not 603 impact consistency. 605 - Routing information exchange upward/downward in the ASON hierarchy 606 involving TE attributes MUST be under strict policy control. 607 Pacing and min/max thresholds for triggered updates are strongly 608 RECOMMENDED. 610 - The number of routing levels MUST be maintained under strict policy 611 control. 613 9. Security Considerations 615 This document specifies the contents and processing of OSPFv2 TE LSAs 616 [RFC3630] and [RFC4202]. The TE LSA extensions defined in this 617 document are not used for SPF computation, and have no direct effect 618 on IP routing. Additionally, ASON routing domains are delimited by 619 the usual administrative domain boundaries. 621 Any mechanisms used for securing the exchange of normal OSPF LSAs can 622 be applied equally to all TE LSAs used in the ASON context. 623 Authentication of OSPFv2 LSA exchanges (such as OSPF cryptographic 624 authentication [RFC2328] and [RFC5709]) can be used to secure against 625 passive attacks and provide significant protection against active 626 attacks. [RFC5709] defines a mechanism for authenticating OSPFv2 627 packets by making use of the HMAC algorithm in conjunction with the 628 SHA family of cryptographic hash functions. 630 If a stronger authentication were believed to be required, then the 631 use of a full digital signature [RFC2154] would be an approach that 632 should be seriously considered. Use of full digital signatures would 633 enable precise authentication of the OSPF router originating each 634 OSPF link-state advertisement, and thereby provide much stronger 635 integrity protection for the OSPF routing domain. 637 RCs implementing export/import of ASON routing information between 638 RAs MUST also include policy control of both the maximum amount of 639 information advertised between RAs and the maximum rate at which it 640 is advertised. This is to isolate the consequences of an RC being 641 compromised to the RAs to which that subverted RC is attached. 643 10. IANA Considerations 645 This document is classified as Standards Track. It defines new sub- 646 TLVs for inclusion in OSPF TE LSAs. According to the assignment 647 policies for the registries of code points for these sub-TLVs, values 648 must be assigned by IANA [RFC3630]. 650 This draft requests early allocation of IANA code points in 651 accordance with [RFC4020]. [NOTE TO RFC Editor: this paragraph and 652 the RFC 4020 reference can be removed during RFC editing]. 654 The following subsections summarize the required sub-TLVs. 656 10.1. Sub-TLVs of the Link TLV 658 This document defines the following sub-TLVs of the Link TLV 659 advertised in the OSPF TE LSA: 661 - Local and Remote TE Router ID sub-TLV (TBDx) 662 - Inter-RA Export Upward sub-TLV (TBDy) 663 - Inter-RA Export Downward sub-TLV (TBDz) 665 Codepoints for these Sub-TLVs should be allocated from the "Types for 666 sub-TLVs of TE Link TLV (Value 2)" registry Standards Action range (0 667 - 32767) [RFC3630]. 669 Note that the same values for the Inter-RA Export Upward sub-TLV and 670 the Inter-RA Export Downward Sub-TLV MUST be used when they appear in 671 the Link TLV, Node Attribute TLV, and Router Address TLV. 673 10.2. Sub-TLVs of the Node Attribute TLV 675 This document defines the following sub-TLVs of the Node Attribute 676 TLV advertised in the OSPF TE LSA: 678 - Local TE Router ID sub-TLV (5) 679 - Inter-RA Export Upward sub-TLV (TBDy) 680 - Inter-RA Export Downward sub-TLV (TBDz) 682 Codepoints for these Sub-TLVs should be assigned from the "Types for 683 sub-TLVs of TE Node Attribute TLV (Value 5)" registry Standards 684 Action range (0 - 32767) [RFC5786]. 686 Note that the same values for the Inter-RA Export Upward sub-TLV and 687 the Inter-RA Export Downward Sub-TLV MUST be used when they appear in 688 the Link TLV, Node Attribute TLV, and Router Address TLV. 690 10.3. Sub-TLVs of the Router Address TLV 692 The Router Address TLV is advertised in the OSPF TE LSA [RFC3630]. 693 Since this TLV currently has no Sub-TLVs defined, a "Types for sub- 694 TLVs of Router Address TLV (Value 1)" registry must be defined. 696 The registry guidelines for the assignment of types for sub-TLVs of 697 the Router Address TLV are as follows: 699 o Types in the range 0-32767 are to be assigned via Standards 700 Action. 702 o Type 0 in the aforementioned standards action range (0-32767) 703 is reserved. 705 o Types in the range 32768-32777 are for experimental use; these 706 will not be registered with IANA, and MUST NOT be mentioned by 707 RFCs. 709 o Types in the range 32778-65535 are not to be assigned at this 710 time. Before any assignments can be made in this range, there 711 MUST be a Standards Track RFC that specifies IANA 712 Considerations that covers the range being assigned. 714 This document defines the following sub-TLVs for inclusion in the 715 Router Address TLV: 717 - Inter-RA Export Upward sub-TLV (TBDy) 718 - Inter-RA Export Downward sub-TLV (TBDz) 720 Codepoints for these Sub-TLVs should be allocated from the "Types for 721 sub-TLVs of Router Address TLV (Value 1)" registry Standards Action 722 range. 724 Note that the same values for the Inter-RA Export Upward sub-TLV and 725 the Inter-RA Export Downward Sub-TLV MUST be used when they appear in 726 the Link TLV, Node Attribute TLV, and Router Address TLV. 728 11. Management Considerations 730 11.1. Routing Area (RA) Isolation 732 If the RA Identifier is mapped to the OSPF Area ID as recommended in 733 section 2.0, OSPF [RFC2328] implicitly provides isolation. On any 734 intra-RA link, packets will only be accepted if the area-id in the 735 OSPF packet header matches the area ID for the OSPF interface on 736 which the packet was received. Hence, RCs will only establish 737 adjacencies and exchange reachability information (see Section 4.0) 738 with RCs in the same RA. Other mechanisms for RA isolation are 739 beyond the scope of this document. 741 11.2 Routing Area (RA) Topology/Configuration Changes 743 The GMPLS Routing for ASON requirements [RFC4258] dictate that the 744 routing protocol MUST support reconfiguration and SHOULD support 745 architectural evolution. OSPF [RFC2328] includes support for the 746 dynamic introduction or removal of ASON reachability information 747 through the flooding and purging of OSPF opaque LSAs [RFC5250]. Also, 748 when an RA is partitioned or an RC fails, stale LSAs SHOULD NOT be 749 used unless the advertising RC is reachable. The configuration of 750 OSPF RAs and the policies governing the redistribution of ASON 751 reachability information between RAs are implementation issues 752 outside of the OSPF routing protocol and beyond the scope of this 753 document. 755 12. Comparison to Requirements in RFC 4258 757 The following table shows how this draft complies with the 758 requirements in [RFC4258]. The first column contains a requirements 759 number (1-30) and the relevant section in RFC 4258. The second column 760 describes the requirement, the third column discusses the compliance 761 to that requirement, and the fourth column lists the relevant section 762 in draft, and/or another RFC that already satisfies the requirement. 764 +----------+---------------------------+---------------+-------------+ 765 | RFC 4258 | RFC 4258 Requirement | Compliance | Reference | 766 | Section | | | | 767 | (Req. | | | | 768 | Number) | | | | 769 +----------+---------------------------+---------------+-------------+ 770 | 3.0 (1) | The failure of an RC, or | Implied by | Not an | 771 | | the failure of | separation of |attribute of | 772 | |communications between RCs,| transport and | routing | 773 | |and the subsequent recovery|control plane. | protocol. | 774 | |from the failure condition | | | 775 | | MUST NOT disrupt call in | | | 776 | | progress. | | | 777 +----------+---------------------------+---------------+-------------+ 778 | 3.1 (2) |Multiple Hierarchical Level| Yes | Sections 2 | 779 | | of ASON Routing Areas | | and 3 | 780 | | (RAs). | | | 781 +----------+---------------------------+---------------+-------------+ 782 | 3.1 (3) | Prior to establishing | Yes, when RA |Section 11.1 | 783 | | communications, RCs MUST | maps to OSPF | | 784 | |verify that they are bound | Area ID. | | 785 | | to the same parent RA. | Otherwise, | | 786 | | | out of scope. | | 787 +----------+---------------------------+---------------+-------------+ 788 | 3.1 (4) | The RC ID MUST be unique | Yes |RFC 2328 and | 789 | | within its containing RA. | | Section 3. | 790 +----------+---------------------------+---------------+-------------+ 791 | 3.1 (5) |Each RA within a carrier's |Yes - although | Sections 2, | 792 | | network SHALL be uniquely | uniqueness is | 3, and 11.1 | 793 | |identifiable. RA IDs MAY be|the operator's | | 794 | |associated with a transport|responsibility.| | 795 | | plane name space, whereas | | | 796 | |RC IDs are associated with | | | 797 | |a control plane name space.| | | 798 +----------+---------------------------+---------------+-------------+ 799 | 3.2 (6) | Hierarchical Routing | Yes | Section 7 | 800 | | Information Dissemination | | | 801 +----------+---------------------------+---------------+-------------+ 802 | 3.2 (7) | Routing Information | Yes | Section 7.1 | 803 | |exchanged between levels N | | | 804 | | and N+1 via separate | | | 805 | | instances and | | | 806 | | import/export. | | | 807 +----------+---------------------------+---------------+-------------+ 808 +----------+---------------------------+---------------+-------------+ 809 | 3.2 (8) | Routing Information | No - Not | | 810 | |exchanged between levels N | described. | | 811 | | and N+1 via external link | | | 812 | | (inter-RA links). | | | 813 +----------+---------------------------+---------------+-------------+ 814 | 3.2 (9) | Routing information | Yes | Sections 4, | 815 | | exchange MUST include | |6, 6.1, 6.2, | 816 | | reachability information | | and 8 | 817 | | and MAY include, upon | | | 818 | | policy decision, node and | | | 819 | | link topology. | | | 820 +----------+---------------------------+---------------+-------------+ 821 | 3.2 (10) | There SHOULD NOT be any |Yes - separate | Sections 2 | 822 | | dependencies on the | instances. | and 3 | 823 | |different routing protocols| | | 824 | | used within an RA or in | | | 825 | | different RAs. | | | 826 +----------+---------------------------+---------------+-------------+ 827 | 3.2 (11) |The routing protocol SHALL | Yes | Section 7.2 | 828 | | differentiate the routing | | | 829 | |information originated at a| | | 830 | |given-level RA from derived| | | 831 | | routing information | | | 832 | | (received from external | | | 833 | | RAs), even when this | | | 834 | |information is forwarded by| | | 835 | | another RC at the same | | | 836 | | level. | | | 837 +----------+---------------------------+---------------+-------------+ 838 | 3.2 (12) | The routing protocol MUST | Yes | Section 7.2 | 839 | | provide a mechanism to | | | 840 | | prevent information | | | 841 | |propagated from a Level N+1| | | 842 | | RA's RC into the Level N | | | 843 | | RA's RC from being | | | 844 | | re-introduced into the | | | 845 | | Level N+1 RA's RC. | | | 846 +----------+---------------------------+---------------+-------------+ 847 | 3.2 (13) | The routing protocol MUST | Yes | Section 7.2 | 848 | | provide a mechanism to | | | 849 | | prevent information | | | 850 | |propagated from a Level N-1| | | 851 | | RA's RC into the Level N | | | 852 | | RA's RC from being | | | 853 | | re-introduced into the | | | 854 | | Level N-1 RA's RC. | | | 855 +----------+---------------------------+---------------+-------------+ 856 +----------+---------------------------+---------------+-------------+ 857 | 3.2 (14) | Instance of a Level N | Yes | Sections 2, | 858 | | routing function and an | | 3, and 7 | 859 | | instance of a Level N+1 | | | 860 | | routing function in the | | | 861 | | same system. | | | 862 +----------+---------------------------+---------------+-------------+ 863 | 3.2 (15) | The Level N routing | Not described | N/A | 864 | | function is on a separate | but possible. | | 865 | | system the Level N+1 | | | 866 | | routing function. | | | 867 +----------+---------------------------+---------------+-------------+ 868 | 3.3 (16) |The RC MUST support static | The automation| Sections 2 | 869 | | (i.e., operator assisted) | requirement is|and 3. Config| 870 | | and MAY support automated | ambiguous. | is product | 871 | | configuration of the | OSPF supports | specific. | 872 | |information describing its | auto-discovery| Refer to | 873 | |relationship to its parent | of neighbors | RFC 2328 for| 874 | | and its child within the | and topology. | OSPF auto- | 875 | | hierarchical structure | Default and | discovery. | 876 | | (including RA ID and RC | automatically | | 877 | | ID). | configured | | 878 | | | polices are | | 879 | | | out of scope. | | 880 +----------+---------------------------+---------------+-------------+ 881 | 3.3 (17) |The RC MUST support static |Yes - when OSPF|RFC 2328 and | 882 | | (i.e., operator assisted) |area maps to RA|Section 11.1 | 883 | | and MAY support automated | discovery is | | 884 | | configuration of the | automatic. | | 885 | |information describing its | | | 886 | | associated adjacencies to | | | 887 | | other RCs within an RA. | | | 888 +----------+---------------------------+---------------+-------------+ 889 | 3.3 (18) |The routing protocol SHOULD| Yes | RFC 2328 | 890 | |support all the types of RC| | | 891 | | adjacencies described in | | | 892 | |Section 9 of [G.7715]. The | | | 893 | | latter includes congruent | | | 894 | |topology (with distributed | | | 895 | | RC) and hubbed topology | | | 896 | |(e.g., note that the latter| | | 897 | | does not automatically | | | 898 | | imply a designated RC). | | | 899 +----------+---------------------------+---------------+-------------+ 900 +----------+---------------------------+---------------+-------------+ 901 | 3.4 (19) |The routing protocol SHOULD| Yes |RFC 2328, RFC| 902 | | be capable of supporting | | 5250, and | 903 | |architectural evolution in | |Section 11.2.| 904 | | terms of the number of | | | 905 | |hierarchical levels of RAs,| | | 906 | |as well as the aggregation | | | 907 | | and segmentation of RAs. | | | 908 +----------+---------------------------+---------------+-------------+ 909 |3.5.2 (20)|Advertisements MAY contain | | | 910 | |the following common set of| | | 911 | | information regardless of | | | 912 | | whether they are link or | | | 913 | | node related: | | | 914 | | - RA ID of the RA to | Yes |Section 7.2.1| 915 | |which the advertisement is | | | 916 | | bounded | | | 917 | | - RC ID of the entity | Yes | RFC 2328 | 918 | | generating the | | | 919 | | advertisement | | | 920 | | - Information to | Yes |RFC 2328, RFC| 921 | | uniquely identify | | 5250 | 922 | | advertisements | | | 923 | | - Information to | No - Must | | 924 | | determine whether an |compare to old | | 925 | | advertisement has been | | | 926 | | updated | | | 927 | | - Information to | Yes |Section 7.2.1| 928 | | indicate when an | | | 929 | | advertisement has been | | | 930 | | derived from a different | | | 931 | | level RA | | | 932 +----------+---------------------------+---------------+-------------+ 933 |3.5.3 (21)|The Node Attributes Node ID|Yes - Prefixes | RFC 5786, | 934 | | and Reachability must be | only for |Section 4 and| 935 | | advertised. It MAY be | reachability | 6 | 936 | | advertised as a set of | | | 937 | |associated external (e.g., | | | 938 | | User Network Interface | | | 939 | | (UNI)) address/address | | | 940 | | prefixes or a set of | | | 941 | | associated SNPP link | | | 942 | | IDs/SNPP ID prefixes, the | | | 943 | |selection of which MUST be | | | 944 | | consistent within the | | | 945 | | applicable scope. | | | 946 +----------+---------------------------+---------------+-------------+ 947 +----------+---------------------------+---------------+-------------+ 948 |3.5.4 (22)| The Link Attributes Local | Yes | Section 6.1 | 949 | | SNPP link ID, Remote SNPP | | | 950 | |link ID, and layer specific| | | 951 | | characteristics must be | | | 952 | | advertised. | | | 953 +----------+---------------------------+---------------+-------------+ 954 |3.5.4 (23)| Link Signaling Attributes | Yes | Section 5, | 955 | |other than Local Adaptation| | RFC 4652 - | 956 | |(Signal Type, Link Weight, | |Section 5.3.1| 957 | | Resource Class, Local | | | 958 | | Connection Types, Link | | | 959 | | Capacity, Link | | | 960 | | Availability, Diversity | | | 961 | | Support) | | | 962 +----------+---------------------------+---------------+-------------+ 963 |3.5.4 (24)| Link Signaling Local | Yes | Section 5.1 | 964 | | Adaptation | | | 965 +----------+---------------------------+---------------+-------------+ 966 | 5 (25) | The routing adjacency | Yes |Section 2, 3,| 967 | | topology (i.e., the | | and 6 | 968 | |associated PC connectivity | | | 969 | |topology) and the transport| | | 970 | |network topology SHALL NOT | | | 971 | |be assumed to be congruent.| | | 972 +----------+---------------------------+---------------+-------------+ 973 | 5 (26) |The routing topology SHALL | Yes |RFC 2328, RFC| 974 | | support multiple links | | 3630 | 975 | | between nodes and RAs. | | | 976 +----------+---------------------------+---------------+-------------+ 977 | 5 (27) |The routing protocol SHALL | Yes |RFC 2328, RFC| 978 | | converge such that the | | 5250 | 979 | | distributed RDBs become | | | 980 | |synchronized after a period| | | 981 | | of time. | | | 982 +----------+---------------------------+---------------+-------------+ 983 | 5 (28) |Self-consistent information|Yes - However, | Section 7.1 | 984 | | at the receiving level | this is not a | | 985 | | resulting from any | routing | | 986 | | transformation (filter, | protocol | | 987 | | summarize, etc.) and | function. | | 988 | | forwarding of information | | | 989 | | from one RC to RC(s) at | | | 990 | | different levels when | | | 991 | |multiple RCs are bound to a| | | 992 | | single RA. | | | 993 +----------+---------------------------+---------------+-------------+ 994 +----------+---------------------------+---------------+-------------+ 995 | 5 (29) | In order to support |Partial - OSPF |RFC 2328 and | 996 | | operator-assisted changes | supports the | RFC 5250 | 997 | | in the containment | purging of | | 998 | | relationships of RAs, the | stale | | 999 | | routing protocol SHALL |advertisements | | 1000 | |support evolution in terms |and origination| | 1001 | | of the number of | of new. The | | 1002 | |hierarchical levels of RAs.|non-disruptive | | 1003 | | For example: support of | behavior is | | 1004 | | non-disruptive operations |implementation | | 1005 | |such as adding and removing| specific. | | 1006 | | RAs at the top/bottom of | | | 1007 | | the hierarchy, adding or | | | 1008 | | removing a hierarchical | | | 1009 | |level of RAs in or from the| | | 1010 | |middle of the hierarchy, as| | | 1011 | | well as aggregation and | | | 1012 | | segmentation of RAs. | | | 1013 +----------+---------------------------+---------------+-------------+ 1014 | 5 (30) | A collection of links and |Yes - Within an| Sections 4 | 1015 | |nodes such as a subnetwork | RA it must be | and 6 | 1016 | | or RA MUST be able to | consistent. | | 1017 | | represent itself to the | | | 1018 | | wider network as a single | | | 1019 | | logical entity with only | | | 1020 | |its external links visible | | | 1021 | | to the topology database. | | | 1022 +----------+---------------------------+---------------+-------------+ 1024 13. References 1026 13.1. Normative References 1028 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1029 Requirement Levels", BCP 14, RFC 2119, March 1997. 1031 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998. 1033 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic 1034 Engineering (TE) Extensions to OSPF Version 2", RFC 1035 3630, September 2003. 1037 [RFC3945] Mannie, E., Ed., "Generalized Multi-Protocol Label 1038 Switching (GMPLS) Architecture", RFC 3945, October 2004. 1040 [RFC4202] Kompella, K., Ed., and Y. Rekhter, Ed., "Routing 1041 Extensions in Support of Generalized Multi-Protocol 1042 Label Switching (GMPLS)", RFC 4202, October 2005. 1044 [RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions 1045 in Support of Generalized Multi-Protocol Label Switching 1046 (GMPLS)", RFC 4203, October 2005. 1048 [RFC5250] Berger, L., Bryskin, I., Zinin, A., and R. Coltun, "The 1049 OSPF Opaque LSA Option", RFC 5250, July 2008. 1051 [RFC5786] Aggarwal, R. and K. Kompella, "Advertising a Router's 1052 Local Addresses in OSPF TE Extensions", RFC 5786, March 1053 2010. 1055 13.2. Informative References 1057 [RFC2154] Murphy, S., Badger, M., and B. Wellington, "OSPF with 1058 Digital Signatures", RFC 2154, June 1997. 1060 [RFC4020] Kompella, K. and A. Zinin, "Early IANA Allocation of 1061 Standards Track Code Points", BCP 100, RFC 4020, 1062 February 2005. 1064 [RFC4258] Brungard, D., Ed., "Requirements for Generalized Multi- 1065 Protocol Label Switching (GMPLS) Routing for the 1066 Automatically Switched Optical Network (ASON)", RFC 1067 4258, November 2005. 1069 [RFC4652] Papadimitriou, D., Ed., Ong, L., Sadler, J., Shew, S., 1070 and D. Ward, "Evaluation of Existing Routing Protocols 1071 against Automatic Switched Optical Network (ASON) 1072 Routing Requirements", RFC 4652, October 2006. 1074 [RFC5709] Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, 1075 M., Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA 1076 Cryptographic Authentication", RFC 5709, October 2009. 1078 For information on the availability of ITU Documents, please see 1079 http://www.itu.int. 1081 [G.7715] ITU-T Rec. G.7715/Y.1306, "Architecture and Requirements 1082 for the Automatically Switched Optical Network (ASON)", 1083 June 2002. 1085 [G.7715.1] ITU-T Rec. G.7715.1/Y.1706.1, "ASON Routing Architecture 1086 and Requirements for Link State Protocols", February 1087 2004. 1089 [G.805] ITU-T Rec. G.805, "Generic Functional Architecture of 1090 Transport Networks)", March 2000. 1092 [G.8080] ITU-T Rec. G.8080/Y.1304, "Architecture for the 1093 Automatically Switched Optical Network (ASON)," June 1094 2006 (and Amendments 1 (March 2008) and 2 (Sept. 2010)). 1096 14. Acknowledgements 1098 The editors would like to thank Lyndon Ong, Remi Theillaud, Stephen 1099 Shew, Jonathan Sadler, Deborah Brungard, Lou Berger, and Adrian 1100 Farrel for their useful comments and suggestions. 1102 14.1 RFC 5787 Acknowledgements 1104 The author would like to thank Dean Cheng, Acee Lindem, Pandian 1105 Vijay, Alan Davey, Adrian Farrel, Deborah Brungard, and Ben Campbell 1106 for their useful comments and suggestions. 1108 Lisa Dusseault and Jari Arkko provided useful comments during IESG 1109 review. 1111 Question 14 of Study Group 15 of the ITU-T provided useful and 1112 constructive input. 1114 Appendix A. ASON Terminology 1116 This document makes use of the following terms: 1118 Administrative domain: (See Recommendation [G.805].) For the 1119 purposes of [G7715.1], an administrative domain represents the 1120 extent of resources that belong to a single player such as a 1121 network operator, a service provider, or an end-user. 1122 Administrative domains of different players do not overlap amongst 1123 themselves. 1125 Control plane: performs the call control and connection control 1126 functions. Through signaling, the control plane sets up and 1127 releases connections, and may restore a connection in case of a 1128 failure. 1130 (Control) Domain: represents a collection of (control) entities that 1131 are grouped for a particular purpose. The control plane is 1132 subdivided into domains matching administrative domains. Within 1133 an administrative domain, further subdivisions of the control 1134 plane are recursively applied. A routing control domain is an 1135 abstract entity that hides the details of the RC distribution. 1137 External NNI (E-NNI): interfaces located between protocol controllers 1138 between control domains. 1140 Internal NNI (I-NNI): interfaces located between protocol controllers 1141 within control domains. 1143 Link: (See Recommendation G.805.) A "topological component" that 1144 describes a fixed relationship between a "subnetwork" or "access 1145 group" and another "subnetwork" or "access group". Links are not 1146 limited to being provided by a single server trail. 1148 Management plane: performs management functions for the transport 1149 plane, the control plane, and the system as a whole. It also 1150 provides coordination between all the planes. The following 1151 management functional areas are performed in the management plane: 1152 performance, fault, configuration, accounting, and security 1153 management. 1155 Management domain: (See Recommendation G.805.) A management domain 1156 defines a collection of managed objects that are grouped to meet 1157 organizational requirements according to geography, technology, 1158 policy, or other structure, and for a number of functional areas 1159 such as configuration, security, (FCAPS), for the purpose of 1160 providing control in a consistent manner. Management domains can 1161 be disjoint, contained, or overlapping. As such, the resources 1162 within an administrative domain can be distributed into several 1163 possible overlapping management domains. The same resource can 1164 therefore 1165 belong to several management domains simultaneously, but a 1166 management domain shall not cross the border of an administrative 1167 domain. 1169 Subnetwork Point (SNP): The SNP is a control plane abstraction that 1170 represents an actual or potential transport plane resource. SNPs 1171 (in different subnetwork partitions) may represent the same 1172 transport resource. A one-to-one correspondence should not be 1173 assumed. 1175 Subnetwork Point Pool (SNPP): A set of SNPs that are grouped together 1176 for the purposes of routing. 1178 Termination Connection Point (TCP): A TCP represents the output of a 1179 Trail Termination function or the input to a Trail Termination 1180 Sink function. 1182 Transport plane: provides bidirectional or unidirectional transfer of 1183 user information, from one location to another. It can also 1184 provide transfer of some control and network management 1185 information. The transport plane is layered; it is equivalent to 1186 the Transport Network defined in Recommendation G.805. 1188 User Network Interface (UNI): interfaces are located between protocol 1189 controllers between a user and a control domain. Note: There is 1190 no routing function associated with a UNI reference point. 1192 Appendix B. ASON Routing Terminology 1194 This document makes use of the following terms: 1196 Routing Area (RA): an RA represents a partition of the transport 1197 plane, and its identifier is used within the control plane as the 1198 representation of this partition. Per [G.8080], an RA is defined 1199 by a set of sub-networks, the links that interconnect them, and 1200 the interfaces representing the ends of the links exiting that RA. 1201 An RA may contain smaller RAs inter-connected by links. The 1202 limit of subdivision results in an RA that contains two sub- 1203 networks interconnected by a single link. 1205 Routing Database (RDB): a repository for the local topology, network 1206 topology, reachability, and other routing information that is 1207 updated as part of the routing information exchange and may 1208 additionally contain information that is configured. The RDB may 1209 contain routing information for more than one routing area (RA). 1211 Routing Components: ASON routing architecture functions. These 1212 functions can be classified as protocol independent (Link Resource 1213 Manager or LRM, Routing Controller or RC) or protocol specific 1214 (Protocol Controller or PC). 1216 Routing Controller (RC): handles (abstract) information needed for 1217 routing and the routing information exchange with peering RCs by 1218 operating on the RDB. The RC has access to a view of the RDB. 1219 The RC is protocol independent. 1221 Note: Since the RDB may contain routing information pertaining to 1222 multiple RAs (and possibly to multiple layer networks), the RCs 1223 accessing the RDB may share the routing information. 1225 Link Resource Manager (LRM): supplies all the relevant component and 1226 TE link information to the RC. It informs the RC about any state 1227 changes of the link resources it controls. 1229 Protocol Controller (PC): handles protocol-specific message exchanges 1230 according to the reference point over which the information is 1231 exchanged (e.g., E-NNI, I-NNI), and internal exchanges with the 1232 RC. The PC function is protocol dependent. 1234 Appendix C. Changes from RFC 5787 1236 This document contains the following changes from RFC 5787: 1238 1. This document will be on the Standards Track rather than 1239 Experimental, and reflects experience gained from RFC 5787 1240 implementation and interoperability testing. This also required 1241 changes to the IANA Considerations. 1243 2. There is a new Section 3 on Terminology and Identification to 1244 describe the mapping of key ASON entities to OSPF entities. 1246 3. Sections were reorganized to explain terminology before defining 1247 prefix extensions. 1249 4. There is a new Section 11, Management Considerations, which 1250 describes how existing OSPF mechanisms address ASON requirements 1251 on Routing Area changes. 1253 5. There is a new Section 12 which compares the document to the 1254 requirements in RFC 4258. 1256 6. The prefix format was changed to reference RFC 5786 rather than 1257 defining a separate format, and The Node Attribute TLV in RFC 5786 1258 has been updated as a result. 1260 7. Routing Information Advertisements were simplified from RFC 5787. 1262 8. Review comments from ITU-T SG15 and the IESG were incorporated. 1264 Authors' Addresses 1266 Andrew G. Malis 1267 Verizon Communications 1268 60 Sylvan Rd. 1269 Waltham MA 02451 USA 1271 EMail: andrew.g.malis@verizon.com 1273 Acee Lindem 1274 Ericsson 1275 102 Carric Bend Court 1276 Cary, NC 27519 1278 EMail: acee.lindem@ericsson.com 1280 Dimitri Papadimitriou 1281 Alcatel-Lucent 1282 Copernicuslaan, 50 1283 2018 Antwerpen, Belgium 1285 EMail: dimitri.papadimitriou@alcatel-lucent.com