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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Network Working Group Adrian Farrel 2 IETF Internet Draft Olddog Consulting 3 Proposed Status: Informational 4 Expires: January 2004 Jean-Philippe Vasseur 5 Cisco Systems, Inc. 7 Arthi Ayyangar 8 Juniper Networks 10 July 2004 12 draft-farrel-ccamp-inter-domain-framework-01.txt 14 A Framework for Inter-Domain MPLS Traffic Engineering 16 Status of this Memo 18 By submitting this Internet-Draft, I certify that any applicable 19 patent or other IPR claims of which I am aware have been disclosed, 20 and any of which I become aware will be disclosed, in accordance with 21 RFC 3667. 23 This document is an Internet-Draft and is in full conformance with 24 all provisions of Section 10 of RFC2026. Internet-Drafts are 25 Working documents of the Internet Engineering Task Force (IETF), its 26 areas, and its working groups. Note that other groups may also 27 distribute working documents as Internet-Drafts. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 The list of current Internet-Drafts can be accessed at 35 http://www.ietf.org/ietf/1id-abstracts.txt. 36 The list of Internet-Draft Shadow Directories can be accessed at 37 http://www.ietf.org/shadow.html. 39 Copyright Notice 41 Copyright (C) The Internet Society (2004). All Rights Reserved. 43 Abstract 45 This document provides a framework for establishing and controlling 46 Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) 47 Label Switched Paths (LSPs) in multi-domain networks. 49 For the purposes of this document, a domain is considered to be any 50 collection of network elements within a common sphere of address 51 management or path computational responsibility. Examples of such 52 domains include IGP areas and Autonomous Systems. 54 1. Introduction 56 The Traffic Engineering Working Group has developed requirements for 57 inter-area and inter-AS MPLS Traffic Engineering in [INTER-AREA] and 58 [INTER-AS]. 60 Various proposals have subsequently been made to address some or all 61 of these requirements through extensions to the RSVP-TE and IGP 62 (ISIS, OSPF) protocols and procedures. 64 This document introduces the techniques for establishing TE LSPs 65 across multiple domains. The functional components of these 66 techniques are separated into the mechanisms for discovering 67 reachability and TE information, for computing the paths of LSPs, and 68 for signaling the LSPs. Note that the aim is this document is not to 69 detail each of those techniques which are covered in separate 70 documents, but rather to propose a framework for inter-domain MPLS 71 Traffic Engineering. 73 For the purposes of this document, a domain is considered to be any 74 collection of network elements within a common sphere of address 75 management or path computational responsibility. Examples of such 76 domains include IGP areas and Autonomous Systems. However, domains of 77 computational responsibility may also exist as sub-domains of areas 78 or ASs. Wholly or partially overlapping domains are not within the 79 scope of this document. 81 1.1. Nested Domains 83 Nested domains are outside the scope of this document. It may be that 84 some domains that are nested administratively or for the purposes of 85 address space management can be considered as adjacent domains for 86 the purposes of this document, however the fact that the domains are 87 nested is then immaterial. 89 In the context of MPLS TE, domain A is considered to be nested within 90 domain B if domain A is wholly contained in Domain B, and domain B is 91 fully or partially aware of the TE characteristics and topology of 92 domain A. 94 For further consideration of nested domains see [MRN] 96 1.2. Conventions used in this document 98 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 99 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 100 document are to be interpreted as described in RFC 2119 [RFC2119]. 102 2. Signaling Options 104 Three distinct options for signaling TE LSPs across multiple domains 105 are identified. The choice of which options to use may be influenced 106 by the path computation technique used (see section 3), although some 107 path computation may apply to multiple TE LSP types. The choice may 108 further depend on the application to which the TE LSPs are put and 109 the nature, topology and switching capabilities of the network. 111 A comparison of the usages of the different signaling options is 112 beyond the scope of this document and should be the subject of a 113 separate applicability statement. 115 2.1. LSP Nesting 117 Forwarding Adjacencies (FAs) are introduced and explained in detail 118 in [HIER]. No further description is necessary in this document. 120 FAs can be used in support of inter-domain TE LSPs. In particular, an 121 FA may be used to achieve connectivity between any pair of LSRs 122 within a domain. The ingress and egress of the FA LSP could be the 123 edge nodes of the domain in which case connectivity is achieved 124 across the entire domain, or they could be any other pair of LSRs in 125 the domain. 127 The technique of carrying one TE LSP within another is termed LSP 128 nesting. An FA may provide a TE LSP tunnel to transport (i.e. nest) 129 multiple TE LSPs along a common part of their paths. Alternatively, a 130 TE LSP may carry (i.e. nest) a single LSP in a one-to-one mapping. 132 The signaling trigger for the establishment of an FA LSP may be the 133 receipt of a signaling request for the TE LSP that it will carry, or 134 may be a management action to 'pre-engineer' a domain to be crossed 135 by TE LSPs that would be used as FAs by the traffic that has to 136 traverse the domain. Furthermore, the mapping (inheritance rules) 137 between attributes of the nested and FA LSPs (including bandwidth) 138 may be statically pre-configured or, for on-demand FA LSPs, may be 139 dynamic according to the properties of the nested LSPs. 141 Note that a hierarchical LSP may be constructed to span multiple 142 domains or parts of domains, however how or whether such an LSP could 143 be advertised as an FA that spans domains is open for study. The end 144 points of a hierarchical LSP are not necessarily on domain 145 boundaries, so nesting is not limited to domain boundaries. 147 Note also that the IGP/EGP routing topology is maintained unaffected 148 by the LSP connectivity and TE links introduced by FA LSPs. That is, 149 the routing protocols do not exchange messages over the FA LSPs, and 150 such LSPs do not create adjacencies between routers. During this 151 operation the SENDER_TEMPLATE and SESSION objects remain unchanged 152 along the entire length of the LSP. 154 2.2. Contiguous LSP 156 A single contiguous LSP is established from ingress to egress in a 157 single signaling exchange. No further LSPs are required be 158 established to support this LSP. Signaling occurs between adjacent 159 neighbors only (no tunneling), and hop-by-hop signaling is used. 161 2.3. LSP Stitching 163 In the LSP stitching model separate LSPs (referred to as a TE LSP 164 segments) are established and are "stitched" together in the data 165 plane so that a single end-to-end label switched path is achieved. 166 The distinction is that the component LSP segments are signaled as 167 distinct TE LSPs in the control plane. Each signaled TE LSP segment 168 has a different source and destination. 170 LSP stitching can be used in support of inter-domain TE LSPs. In 171 particular, an LSP segment may be used to achieve connectivity 172 between any pair of LSRs within a domain. The ingress and egress of 173 the LSP segment could be the edge nodes of the domain in which case 174 connectivity is achieved across the entire domain, or they could be 175 any other pair of LSRs in the domain. 177 The signaling trigger for the establishment of a TE LSP segment may 178 be the establishment of the previous TE LSP segment, the receipt of 179 setup request for TE LSP that it plans to stitch to a local TE LSP 180 segment, or may be a management action. 182 2.4. Hybrid Methods 184 There is nothing to prevent the mixture of signaling methods 185 described above when establishing a single, end-to-end, inter-domain 186 TE LSP. It may be desirable in this case for the choice of the 187 various methods to be indicated along the path perhaps through the 188 RRO. 190 If there is a desire to restrict which methods are used, this MUST be 191 signaled as described in the next section. 193 2.5. Control of Downstream Choice of Signaling Method 195 Notwithstanding the previous section, an ingress LSR MAY wish to 196 restrict the signaling methods applied to a particular LSP at domain 197 boundaries across the network. Such control, where it is required, 198 may be achieved by the definition of appropriate new flags in the 199 SESSION-ATTRIBUTE object or the Attributes Flags TLV of the 200 LSP_ATTRIBUTES object [ATTRIB]. Before defining a mechanism to 201 provide this level of control, the functional requirement to control 202 the way in which the network delivers a service must be established 203 and due consideration must be given to the impact on 204 interoperability. 206 3. Path Computation Techniques 208 The discussion of path computation techniques within this document is 209 limited significantly to the determination of where computation may 210 take place and what components of the full path may be determined. 212 The techniques used are closely tied to the signaling methodologies 213 described in the previous section in that certain computation 214 techniques may require the use of particular signaling approaches and 215 vice versa. 217 Any discussion of the appropriateness of a particular path 218 computation technique in any given circumstance is beyond the scope 219 of this document and should be described in a separate applicability 220 statement. 222 3.1. Management Configuration 224 Path computation may be performed by offline tools or by a network 225 planner. The resultant path may be supplied to the ingress LSR as 226 part of the TE LSP or service request, and encoded by the ingress LSR 227 as an ERO on the Path message that is sent out. 229 There is no reason why the path provided by the operator should not 230 span multiple domains if the relevant information is available to the 231 planner or the offline tool. The definition of what information is 232 needed to perform this operation and how that information is 233 gathered, is outside the scope of this document. 235 3.2. Head End Computation 237 The head end, or ingress, LSR may assume responsibility for path 238 computation when the operator supplies part or none of the explicit 239 path. The operator MUST, in any case, supply at least the destination 240 address (egress) of the LSP. 242 3.2.1. Multi-Domain Visibility Computation 244 If the ingress has sufficient visibility of the topology and TE 245 information for all of the domains across which it will route the LSP 246 to its destination then it may compute and provide the entire path. 247 The quality of this path is best if the ingress has full visibility 248 into all relevant domains rather than just sufficient visibility to 249 provide some path to the destination. 251 Extreme caution must be exercised in consideration of the 252 distribution of the requisite TE information. See section 4. 254 3.2.2. Partial Visibility Computation 256 It may be that the ingress does not have full visibility of the 257 topology of all domains, but does have information about the 258 connectedness of the domains and the TE resource availability across 259 the domains. In this case, the ingress is not able to provide a fully 260 specified strict explicit path from ingress to egress. However, the 261 ingress can supply an explicit path that comprises: 262 - explicit hops from ingress to the local domain boundary 263 - loose hops representing the domain entry points across the network 264 - a loose hop identifying the egress. 266 Alternatively, the explicit path may be expressed as: 267 - explicit hops from ingress to the local domain boundary 268 - strict hops giving abstract nodes representing each domain in turn 269 - a loose hop identifying the egress. 271 These two explicit path formats may be mixed. 273 This form of explicit path relies on some further computation 274 technique being applied at the domain boundaries. See section 3.3. 276 As with the multi-domain visibility option, extreme caution must be 277 exercised in consideration of the distribution of the requisite TE 278 information. See section 4. 280 3.2.3. Local Domain Visibility Computation 282 A final possibility for ingress-based computation is that the ingress 283 LSR has visibility only within its own domain, and connectivity 284 information only as far as determining one or more domain exit points 285 that may be suitable for carrying the LSP to its egress. 287 In this case the ingress builds an explicit path that comprises just: 288 - explicit hops from ingress to the local domain boundary 289 - a loose hop identifying the egress. 291 3.3. Domain Boundary Computation 293 If the partial explicit path methods described in sections 3.2.2 or 294 3.2.3 are applied then the LSR at each domain boundary is responsible 295 for ensuring that there is sufficient path information added to the 296 Path message to carry it at least to the next domain boundary (that 297 is, out of the new domain). 299 If the LSR at the domain boundary has full visibility to the egress 300 then it can supply the entire explicit path. Note however, that the 301 ERO processing rules of [RFC3209] state that it SHOULD only update 302 the ERO as far as the next specified hop (that is, the next domain 303 boundary if one was supplied in the original ERO) and, of course, 304 MUST NOT insert ERO subobjects immediately before a strict hop. 306 If the LSR at the domain boundary has only partial visibility (using 307 the definitions of section 3.2.2) it will fill in the path as far as 308 the next domain boundary, and will supply further domain/domain 309 boundary information if not already present in the ERO. 311 If the LSR at the domain boundary has only local visibility into the 312 immediate domain it will simply add information to the ERO to carry 313 the Path message as far as the next domain boundary. 315 3.4. Path Computation Element 317 The computation techniques in sections 3.2 and 3.3 rely on topology 318 and TE information being distributed to the ingress LSR and those 319 LSRs at domain boundaries. These LSRs are responsible for computing 320 paths. Note that there may be scaling concerns with distributing the 321 required information - see section 4. 323 An alternative technique places the responsibility for path 324 computation with a Path Computation Element (PCE). There may be 325 either a centralized PCE, or multiple PCEs (each having a local 326 visibility and collaborating in a distributed fashion to compute an 327 end to end path) across the entire network and even within any one 328 domain. The PCE may collect topology and TE information from the same 329 sources as would be used by LSRs in the paragraph, or though other 330 means. 332 Each LSR called upon to perform path computation (and even the 333 offline management tools described in section 3.1) may abdicate the 334 task to a PCE of its choice. The selection of PCE(s) may be driven by 335 static configuration or the dynamic discovery by means of IGP or BGP 336 extensions. 338 3.4.1. Multi-Domain Visibility Computation 340 A PCE may have full visibility, perhaps through connectivity to 341 multiple domains. In this case it is able to supply a full explicit 342 path as in section 3.2.1. 344 3.4.2. Path Computation Use of PCE When Preserving Confidentiality 346 Note that although a centralized PCE or multiple collaborative PCEs 347 may have full visibility into one or more domains, it may be 348 desirable (e.g to preserve confidentiality) that the full path is not 349 provided to the ingress LSR. Instead, a partial path is supplied (as 350 in section 3.2.2 or 3.2.3) and the LSRs at each domain boundary are 351 required to make further requests for each successive segment of the 352 path. 354 In this way an end-to-end path may be computed using the full network 355 capabilities, but confidentiality between domains may be preserved. 356 Optionally, the PCE(s) may compute the entire path at the first 357 request and hold it in storage for subsequent requests, or it may 358 recompute the best path on each request or at regular intervals. 360 It may be the case that the centralized PCE or the collaboration 361 between PCEs may define a trust relationship greater than that 362 normally operational between domains. 364 3.4.3. Per-Domain Computation Servers 366 A third way that PCEs may be used is simply to have one (or more) per 367 domain. Each LSR within a domain that wishes to derive a path across 368 the domain may consult its local PCE. 370 This mechanism could be used for all path computations within the 371 domain, or specifically limited to computations for LSPs that will 372 leave the domain where external connectivity information can then be 373 restricted to just the PCE. 375 3.5. Optimal Path Computation 377 An optimal route might be defined as the route that would be computed 378 in the absence of domain boundaries. It is easy to construct examples 379 that show that partitioning a network into domains, and the resulting 380 loss or aggregation of routing information may lead to the 381 computation of routes that are other than optimal. It is impossible 382 to guarantee optimal routing in the presence of aggregation / 383 abstraction / summarization of routing information. 385 It is beyond the scope of this document to define what is an optimum 386 path for an inter-domain TE LSP. This debate is abdicated in favor of 387 requirements documents and applicability statements. Note, however, 388 that the meaning of certain computation metrics may differ between 389 domains (see section 5.6). 391 4. Distributing Reachability and TE Information 393 The path computation techniques described in the previous section 394 make certain demands upon the distribution of reachability 395 information and the TE capabilities of nodes and links within domains 396 as well as the TE connectivity across domains. 398 Currently, TE information is distributed within domains by additions 399 to IGPs [RFC3630], [RFC3784]. 401 In cases where two domains are interconnected by one or more links 402 (that is, the domain boundary falls on a link rather than on a node), 403 there SHOULD be a mechanism to distribute the TE information 404 associated with the links to the corresponding domains. This would 405 facilitate better path computation and reduce TE-related crankbacks 406 on these links. 408 Where a domain is a subset of an IGP area, filtering of TE 409 information may be applied at the domain boundary. This filtering may 410 be one way, or two way. 412 Where information needs to reach a PCE that spans multiple domains, 413 the PCE may snoop on the IGP traffic in each domain, or play an 414 active part as an IGP-capable node in each domain. The PCE might also 415 receive TEDB updates from a proxy within the domain. 417 It could be possible that an LSR that performs path computation (for 418 example, and ingress LSR) obtains the topology and TE information of 419 not just its own domain, but other domains as well. This information 420 may be subject to filtering applied by the advertising domain (for 421 example, the information may be limited to FAs across other domains, 422 or the information may be aggregated or abstracted). 424 Where any cross-domain reachability and TE information needs to be 425 advertised, consideration must be given to TE extensions to BGP, and 426 how these may be fed to the IGPs. Techniques for inter-domain TE 427 aggregation are also for further study. However, it must be noted 428 that any extensions that cause a significant increase in the amount 429 of processing (such as aggregation computation) at domain boundaries, 430 or a significant increase in the amount of information flooded (such 431 as detailed TE information) need to be treated with extreme caution 432 and compared carefully with the scaling requirements expressed in 433 [INTER-AREA] and [INTER-AS]. 435 5. Comments on Advanced Functions 437 This section provides some non-definitive comments on the constraints 438 placed on advanced MPLS TE functions by inter-domain MPLS. It does 439 not attempt to state the implications of using one inter-domain 440 technique or another. Such material is deferred to appropriate 441 applicability statements where statements about the capabilities of 442 existing or future signaling, routing and computation techniques to 443 deliver the functions listed should be made. 445 5.1. LSP Re-Optimization 447 Re-optimization is the process of moving a TE LSP from one path to 448 another, more preferable path (where no attempt is made in this 449 document to define 'preferable' as no attempt was made to define 450 'optimal'). Make-before-break techniques are usually applied to 451 ensure that traffic is disrupted as little as possible. The Shared 452 Explicit style is usually used to avoid double booking of network 453 resources. 455 Re-optimization may be available within a single domain. 456 Alternatively, re-optimization may involve a change in route across 457 several domains or might involve a choice of different transit 458 domains. 460 Re-optimization requires that all or part of the path of the LSP be 461 re-computed. The techniques used may be selected as described in 462 section 3, and this will influence whether the whole or part of the 463 path is re-optimized. 465 The trigger for path computation and re-optimization may be an 466 operator request, a timer, or information about a change in 467 availability of network resources. This trigger MUST be applied to 468 the point in the network that requests re-computation and controls 469 re-optimization and may require additional signaling. 471 Note also that where multiple diverse paths are applied end-to-end 472 (i.e. not simply within protection domains - see section 5.5) the 473 point of calculation for re-optimization (whether it is PCE, ingress, 474 or domain entry point) needs to know all such paths before attempting 475 re-optimization of any one path. 477 5.2. LSP Setup Failure 479 When an inter-domain LSP setup fails in some domain other than the 480 first, various options are available for reporting and retrying the 481 LSP. 483 In the first instance, a retry may be attempted within the domain 484 that contains the failure. That retry may be attempted by nodes 485 wholly within the domain, or the failure may be referred back to the 486 LSR at the domain boundary. 488 If the failure cannot be bypassed within the domain where the failure 489 occurred (perhaps there is no suitable alternate route, perhaps 490 rerouting is not allowed by domain policy, or perhaps the Path 491 message specifically bans such action), the error MUST be reported 492 back to the previous or head-end domain. 494 Subsequent repair attempts may be made by domains further upstream, 495 but will only be properly effective if sufficient information about 496 the failure and other failed repair attempts is also passed back 497 upstream [CRANKBACK]. Note that there is a tension between this 498 requirement and that of confidentiality although crankback 499 aggregation may be applicable at domain boundaries. 501 Further attempts to signal the failed LSP may apply the information 502 about the failures as constraints to path computation, or may signal 503 them as specific path exclusions [EXCLUDE]. 505 When requested by signaling, the failure may also be systematically 506 reported to the head-end LSR. 508 5.3. LSP Repair 510 An LSP that fails after it has been established may be repaired 511 dynamically by re-routing. The behavior in this case is either like 512 that for re-optimization, or for handling setup failures (see 513 previous two sections). 515 Fast Reroute may also be used (see below). 517 5.4. Fast Reroute 519 MPLS Traffic Engineering Fast Reroute ([FRR]) defines local 520 protection schemes intended to provide fast recovery (in 10s of 521 msecs) of fast-reroutable TE LSPs upon link/SRLG/Node failure. A 522 backup TE LSP is configured and signaled at each hop, and activated 523 upon detecting or being informed of a network element failure. The 524 node immediately upstream of the failure (called the PLR (Point of 525 Local Repair)) reroutes the set of protected TE LSPs onto the 526 appropriate backup tunnel(s) and around the failed resource. 528 In the context of inter-domain TE, there are several different 529 failure scenarios that must be analyzed. Provision of suitable 530 solutions may be further complicated by the fact that [FRR] specifies 531 two distinct modes of operation referred to as the "one to one mode" 532 and the "facility back-up mode". 534 The failure scenarios specific to inter-domain TE are as follows: 535 - Failure of a domain edge node that is present in both domains. 536 There are two sub-cases: 537 - The PLR and the MP are in the same domain 538 - The PLR and the MP are in different domains. 539 - Failure of a domain edge node that is only present in one of the 540 domains. 541 - Failure of an inter-domain link. 543 The techniques that must be employed to use Fast Reroute for the 544 different methods of signaling LSPs identified in section 2 differ 545 considerably. These should be explained further in applicability 546 statements of, in the case, of a change in base behavior, in 547 implementation guidelines specific to the signaling techniques. 549 Note that after local repair has been performed, it may be desirable 550 to re-optimize the LSP (see section 5.1). If the point of re- 551 optimization (for example the ingress LSR) lies in a different domain 552 to the failure, it may rely on the delivery of a PathErr or Notify 553 message to inform it of the local repair event. 555 5.5. Comments on Path Diversity 557 Diverse paths may be required in support of load sharing and/or 558 protection. Such diverse paths may be required to be node diverse, 559 link diverse, fully path diverse (that is, link and node diverse), or 560 SRLG diverse. 562 Diverse path computation is a classic problem familiar to all graph 563 theory majors. The problem is compounded when there are areas of 564 'private knowledge' such as when domains do not share topology 565 information. The problem is generally considered to be easier and 566 more efficient when the diverse paths can be computed 567 'simultaneously' on the fullest set of information. That being said, 568 various techniques (out of the scope of this document) exist to 569 ensure end to end path diversity across multiple domains. 571 Many network technologies utilize 'protection domains' because they 572 fit well with the capabilities of the technology. As a result, many 573 domains are operated as protection domains. In this model, protection 574 paths converge at domain boundaries. 576 5.6. Domain-Specific Constraints 578 While the meaning of certain constraints, like bandwidth, can be 579 assumed to be constant across different domains, other TE constraints 580 (such as resource affinity, color, metric, priority, etc.) may have 581 different meanings in different domains and this may impact the 582 ability to support DiffServ-aware MPLS, or to manage pre-emption. 584 In order to achieve consistent meaning and LSP establishment, this 585 fact must be considered when performing constraint-based path 586 computation or when signaling across domain boundaries. 588 A mapping function can be derived for most constraints based on 589 policy agreements between the Domain administrators. 591 5.7. Policy Control 593 Domain boundaries are natural points for policy control. There is 594 little to add on this subject except to note that a TE LSP that 595 cannot be established on a path through one domain because of a 596 policy applied at the domain boundary, may be satisfactorily 597 established using a path that avoids the demurring domain. In any 598 case, when a TE LSP signaling attempt is rejected due to non 599 compliance with some policy constraint, this SHOULD be reflected to 600 the ingress LSR. 602 5.8. Inter-domain OAM 604 Some elements of OAM may be intentionally confined within a domain. 605 Others (such as end-to-end liveness and connectivity testing) clearly 606 need to span the entire multi-domain TE LSP. Where issues of 607 confidentiality are strong, collaboration between PCEs or domain 608 boundary nodes might be required in order to provide end-to-end OAM. 610 The different signaling mechanisms described above may need 611 refinements to [LSPPING], [BFD-MPLS] or the use of [TUNTRACE] to gain 612 full end-to-end visibility. These protocols should, however, be 613 considered in the light of confidentiality requirements. 615 Route recording is a commonly used feature of signaling that provides 616 OAM information about the path of an established LSP. When an LSP 617 traverses a domain boundary, the border node may remove or aggregate 618 some of the recorded information for confidentiality or other policy 619 reasons. 621 5.9. Point to Multipoint 623 Inter-domain point-to-multipoint (P2MP) requirements are explicitly 624 out of scope of this document. They may be covered by other documents 625 dependent on the details of MPLS TE P2MP solutions. 627 6. Security Considerations 629 Requirements for security within domains are unchanged from [RFC3209] 630 and [RFC3473], but requirements for inter-domain security are, if 631 anything, more significant. 633 Authentication techniques identified for use with RSVP-TE can only 634 operate across domain boundaries if there is coordination between the 635 administrators of those domains. 637 Confidentiality may also be considered to be security factors. 639 Applicability statements for particular combinations of signaling, 640 routing and path computation techniques are expected to contain 641 detailed security sections. 643 7. Acknowledgements 645 The authors would like to extend their warmest thanks to Kireeti 646 Kompella for convincing them to expend efforts on this document. 648 Grateful thanks to Dimitri Papadimitriou and Tomohiro Otani for their 649 review and suggestions on the text. 651 8. Intellectual Property Considerations 653 The IETF takes no position regarding the validity or scope of any 654 Intellectual Property Rights or other rights that might be claimed to 655 pertain to the implementation or use of the technology described in 656 this document or the extent to which any license under such rights 657 might or might not be available; nor does it represent that it has 658 made any independent effort to identify any such rights. Information 659 on the procedures with respect to rights in RFC documents can be 660 found in BCP 78 and BCP 79. 662 Copies of IPR disclosures made to the IETF Secretariat and any 663 assurances of licenses to be made available, or the result of an 664 attempt made to obtain a general license or permission for the use of 665 such proprietary rights by implementers or users of this 666 specification can be obtained from the IETF on-line IPR repository at 667 http://www.ietf.org/ipr. 669 The IETF invites any interested party to bring to its attention any 670 copyrights, patents or patent applications, or other proprietary 671 rights that may cover technology that may be required to implement 672 this standard. Please address the information to the IETF at ietf- 673 ipr@ietf.org. 675 9. Normative References 677 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 678 Requirement Levels", BCP 14, RFC 2119, March 1997. 680 [RFC3209] Awduche, et al, "Extensions to RSVP for LSP Tunnels", 681 RFC 3209, December 2001. 683 [RFC3473] Berger, L., Editor "Generalized Multi-Protocol Label 684 Switching (GMPLS) Signaling - Resource ReserVation 685 Protocol-Traffic Engineering (RSVP-TE) Extensions", 686 RFC 3473, January 2003. 688 [RFC3667] Bradner, S., "IETF Rights in Contributions", BCP 78, 689 RFC 3667, February 2004. 691 [RFC3668] Bradner, S., Ed., "Intellectual Property Rights in IETF 692 Technology", BCP 79, RFC 3668, February 2004. 694 [HIER] Kompella K., Rekhter Y., "LSP Hierarchy with 695 Generalized MPLS TE", draft-ietf-mpls-lsp-hierarchy-08. 696 txt, March 2002 (work in progress). 698 [INTER-AREA] Le Roux, Vasseur et Boyle, "Requirements for support of 699 Inter-Area and Inter-AS MPLS Traffic Engineering", 700 draft-ietf-tewg-interarea-mpls-te-req-02.txt, June 2004 701 (work in progress). 703 [INTER-AS] Zhang, R., Vasseur, JP. et al, "MPLS Inter-AS Traffic 704 Engineering requirements", draft-ietf-tewg-interas- 705 mpls-te-req-07.txt, June 2004 (work in progress). 707 10. Informational References 709 [RFC3630] Katz, D., Yeung, D., Kompella, K., "Traffic Engineering 710 Extensions to OSPF Version 2", RFC 3630, September 2003 712 [RFC3784] Li, T., Smit, H., "IS-IS extensions for Traffic 713 Engineering", RFC 3784, June 2004. 715 [ATTRIB] A. Farrel, D. Papadimitriou, JP. Vasseur, "Encoding of 716 Attributes for Multiprotocol Label Switching (MPLS) 717 Label Switched Path (LSP) Establishment Using RSVP-TE", 718 draft-ietf-mpls-rsvpte-attributes-03.txt, March 2004 719 (work in progress). 721 [BFD-MPLS] R. Aggarwal and K. Kompella, "BFD For MPLS LSPs", (work 722 in progress). 724 [CRANKBACK] Farrel, A., et al., "Crankback Signaling Extensions for 725 MPLS Signaling", draft-ietf-ccamp-crankback-01.txt, 726 January 2004 (work in progress). 728 [EXCLUDE] Lee et all, Exclude Routes - Extension to RSVP-TE, 729 draft-ietf-ccamp-rsvp-te-exclude-route-01.txt, December 730 2003 (work in progress). 732 [FRR] Ping Pan, et al, "Fast Reroute Extensions to RSVP-TE 733 for LSP Tunnels", draft-ietf-mpls-rsvp-lsp-fastreroute- 734 06.txt, (work in progress). 736 [LSPPING] Kompella, K., et al., " Detecting Data Plane Liveliness 737 in MPLS", Internet Draft draft-ietf-mpls-lsp-ping- 738 05.txt, February 2004 (work in progress). 740 [MRN] Papadimitriou, D., et al., "Generalized MPLS 741 Architecture for Multi-Region Networks", draft- 742 vigoureux-shiomoto-ccamp-gmpls-mrn-04.txt, February 743 2004 (work in progress). 745 [OVERLAY] G. Swallow et al, "GMPLS RSVP Support for the Overlay 746 Model", draft-ietf-ccamp-gmpls-overlay-04.txt, April 747 2004 (work in progress). 749 [TUNTRACE] Bonica, R., et al., "Generic Tunnel Tracing Protocol 750 (GTTP) Specification", draft-ietf-ccamp-tunproto-00, 751 March 2004 (work in progress). 753 11. Authors' Addresses 755 Adrian Farrel 756 Old Dog Consulting 757 EMail: adrian@olddog.co.uk 759 Jean-Philippe Vasseur 760 Cisco Systems, Inc. 761 300 Beaver Brook Road 762 Boxborough , MA - 01719 763 USA 764 Email: jpv@cisco.com 766 Arthi Ayyangar 767 Juniper Networks, Inc 768 1194 N.Mathilda Ave 769 Sunnyvale, CA 94089 770 USA 771 Email: arthi@juniper.net 773 12. Disclaimer of Validity 775 This document and the information contained herein are provided on an 776 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 777 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET 778 ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, 779 INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE 780 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 781 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 783 13. Full Copyright Statement 785 Copyright (C) The Internet Society (2004). This document is subject 786 to the rights, licenses and restrictions contained in BCP 78, and 787 except as set forth therein, the authors retain all their rights.