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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) No issues found here. Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 MPLS WG K. Kompella 3 Internet-Draft Juniper Networks, Inc. 4 Intended status: Standards Track L. Contreras 5 Expires: September 9, 2015 Telefonica I+D 6 March 8, 2015 8 Resilient MPLS Rings 9 draft-kompella-mpls-rmr-01 11 Abstract 13 This document describes the use of the MPLS control and data planes 14 on ring topologies. It describes the special nature of rings, and 15 proceeds to show how MPLS can be effectively used in such topologies. 16 It describes how MPLS rings are configured, auto-discovered and 17 signaled, as well as how the data plane works. Companion documents 18 describe the details of discovery and signaling for specific 19 protocols. 21 Requirements Language 23 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 24 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 25 document are to be interpreted as described in [RFC2119]. 27 Status of This Memo 29 This Internet-Draft is submitted in full conformance with the 30 provisions of BCP 78 and BCP 79. 32 Internet-Drafts are working documents of the Internet Engineering 33 Task Force (IETF). Note that other groups may also distribute 34 working documents as Internet-Drafts. The list of current Internet- 35 Drafts is at http://datatracker.ietf.org/drafts/current/. 37 Internet-Drafts are draft documents valid for a maximum of six months 38 and may be updated, replaced, or obsoleted by other documents at any 39 time. It is inappropriate to use Internet-Drafts as reference 40 material or to cite them other than as "work in progress." 42 This Internet-Draft will expire on September 9, 2015. 44 Copyright Notice 46 Copyright (c) 2015 IETF Trust and the persons identified as the 47 document authors. All rights reserved. 49 This document is subject to BCP 78 and the IETF Trust's Legal 50 Provisions Relating to IETF Documents 51 (http://trustee.ietf.org/license-info) in effect on the date of 52 publication of this document. Please review these documents 53 carefully, as they describe your rights and restrictions with respect 54 to this document. Code Components extracted from this document must 55 include Simplified BSD License text as described in Section 4.e of 56 the Trust Legal Provisions and are provided without warranty as 57 described in the Simplified BSD License. 59 Table of Contents 61 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 62 1.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 3 63 2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 4 64 3. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 5 65 3.1. Provisioning . . . . . . . . . . . . . . . . . . . . . . 5 66 3.2. Ring Nodes . . . . . . . . . . . . . . . . . . . . . . . 5 67 3.3. Ring Links and Directions . . . . . . . . . . . . . . . . 6 68 3.3.1. Bypass Links . . . . . . . . . . . . . . . . . . . . 6 69 3.4. Ring LSPs . . . . . . . . . . . . . . . . . . . . . . . . 6 70 3.5. Installing Primary LFIB Entries . . . . . . . . . . . . . 7 71 3.6. Installing FRR LFIB Entries . . . . . . . . . . . . . . . 7 72 3.7. Protection . . . . . . . . . . . . . . . . . . . . . . . 7 73 4. Autodiscovery . . . . . . . . . . . . . . . . . . . . . . . . 8 74 4.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 8 75 4.2. Ring Announcement Phase . . . . . . . . . . . . . . . . . 10 76 4.3. Mastership Phase . . . . . . . . . . . . . . . . . . . . 11 77 4.4. Ring Identification Phase . . . . . . . . . . . . . . . . 11 78 4.5. Ring Changes . . . . . . . . . . . . . . . . . . . . . . 11 79 5. Ring Signaling . . . . . . . . . . . . . . . . . . . . . . . 11 80 6. Ring OAM . . . . . . . . . . . . . . . . . . . . . . . . . . 12 81 7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 82 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 83 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 84 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 85 10.1. Normative References . . . . . . . . . . . . . . . . . . 12 86 10.2. Informative References . . . . . . . . . . . . . . . . . 12 87 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 89 1. Introduction 91 Rings are a very common topology in transport networks. A ring is 92 the simplest topology offering link and node resilience. Rings are 93 nearly ubiquitous in access and aggregation networks. As MPLS 94 increases its presence in such networks, and takes on a greater role 95 in transport, it is imperative that MPLS handles rings well; this is 96 not the case today. 98 This document describes the special nature of rings, and the special 99 needs of MPLS on rings. It then shows how these needs can be met in 100 several ways, some of which involve extensions to protocols such as 101 IS-IS [RFC5305], OSPF[RFC3630], RSVP-TE [RFC3209] and LDP [RFC5036]. 103 1.1. Definitions 105 A (directed) graph G = (V, E) consists of a set of vertices (or 106 nodes) V and a set of edges (or links) E. An edge is an ordered pair 107 of nodes (a, b), where a and b are in V. (In this document, the 108 terms node and link will be used instead of vertex and edge.) 110 A ring is a subgraph of G. A ring consists of a subset of n nodes 111 {R_i, 0 <= i < n} of V. The directed edges {(R_i, R_i+1) and (R_i+1, 112 R_i), 0 <= i < n-1} must be a subset of E (note that index arithmetic 113 is done modulo n). We define the direction from node R_i to R_i+1 as 114 "clockwise" (CW) and the reverse direction as "anticlockwise" (AC). 115 As there may be several rings in a graph, we number each ring with a 116 distinct ring ID RID. 118 R0 . . . R1 119 . . 120 R7 R2 121 Anti- | . Ring . | 122 Clockwise | . . | Clockwise 123 v . RID = 17 . v 124 R6 R3 125 . . 126 R5 . . . R4 128 Figure 1: Ring with 8 nodes 130 The following terminology is used for ring LSPs: 132 Ring ID (RID): A non-zero number that identifies a ring; this is 133 unique in some scope of a Service Provider's network. An RID of 0 134 means the node is a "promiscuous" node. 136 Node index: A logical numbering of nodes in a ring, from zero upto 137 one less than the ring size. Used purely for exposition in this 138 document. 140 Ring master: The ring master initiates the ring identification 141 process. Mastership is indicated in the IGP by a two-bit field. 143 Ring neighbors: Nodes whose indices differ by one (modulo ring 144 size). 146 Ring links: Links that connnect ring neighbors. 148 Bypass links: Links that connnect non-neighboring ring nodes. 150 Ring direction: A two-bit field in the IGP indicating the direction 151 of a link. The choices are: 153 UN: 00 undefined link 155 CW: 01 clockwise ring link 157 AC: 10 anticlockwise ring link 159 BY: 11 bypass link 161 Ring Identification: The process of discovering ring nodes, ring 162 links, link directions, and bypass links. 164 The following notation is used for ring LSPs: 166 R_k: A ring node with index k. R_k has AC neighbor R_(k-1) and CW 167 neighbor R_(k+1). 169 RL_k: A (unicast) Ring LSP anchored on node R_k. 171 CL_jk (AL_jk): A label allocated by R_j for RL_k in the CW (AC) 172 direction. 174 P_jk (Q_jk): A Path (Resv) message sent by R_j for RL_k. 176 2. Motivation 178 A ring is the simplest topology that offers resilience. This is 179 perhaps the main reason to lay out fiber in a ring. Thus, effective 180 mechanisms for fast failover on rings are needed. Furthermore, there 181 are large numbers of rings. Thus, configuration of rings needs to be 182 as simple as possible. Finally, bandwidth management on access rings 183 is very important, as bandwidth is generally quite constrained here. 185 The goals of this document are to present mechanisms for improved 186 MPLS-based resilience in ring networks (using ideas that are 187 reminiscent of Bidirectional Line Switched Rings), for automatic 188 bring-up of LSPs, better bandwidth management and for auto-hierarchy. 189 These goals can be achieved using extensions to existing IGP and MPLS 190 signaling protocols, using central provisioning, or in other ways. 192 3. Theory of Operation 194 Say a ring has ring ID RID. The ring is provisioned by choosing one 195 or more ring masters for the ring and assigning them the RID. Other 196 nodes in the ring may also be assigned this RID, or may be configured 197 as "promiscuous". Ring discovery then kicks in. When each ring node 198 knows its CW and AC ring neighbors and its ring links, and all bypass 199 links have been identified, ring identification is complete. 201 Once ring identification is complete, each node signals one or more 202 ring LSPs RL_i. RL_i, anchored on node R_i, consists of two counter- 203 rotating unicast LSPs that start and end at R_i. A ring LSP is 204 "multipoint": any node R_j can use RL_i to send traffic to R_i; this 205 can be in either the CW or AC directions, or both (i.e., load 206 balanced). Both of these counter-rotating LSPs are "active"; the 207 choice of direction to send traffic to R_i is determined by policy at 208 the node where traffic is injected into the ring. The default is to 209 send traffic along the shortest path. Bidirectional connectivity 210 between nodes R_i and R_j is achieved by using two different ring 211 LSPs: R_i uses RL_j to reach R_j, and R_j uses RL_i to reach R_i. 213 3.1. Provisioning 215 The goal here is to provision rings with the absolute minimum 216 configuration. The exposition below aims to achieve that using auto- 217 discovery via a link-state IGP (see Section 4). Of course, auto- 218 discovery can be overriden by configuration. For example, a link 219 that would otherwise be classified by auto-discovery as a ring link 220 might be configured not to be used for ring LSPs. 222 3.2. Ring Nodes 224 Ring nodes have a loopback address, and run a link-state IGP and an 225 MPLS signaling protocol. To provision a node as a ring node for ring 226 RID, the node is simply assigned that RID. A node may be part of 227 several rings, and thus may be assigned several ring IDs. 229 To simplify ring provisioning even further, a node N may be made 230 "promiscuous" by being assigned an RID of 0. A promiscuous node 231 listens to RIDs in its IGP neighbors' link-state updates. If N hears 232 a non-zero RID from a neighbor, it joins that ring by taking on that 233 RID. However, if N hears more than one non-zero RID from its 234 neighbors, N remains in promiscuous mode. In many situations, the 235 use of promiscuous mode means that only one or two nodes in the ring 236 needs to be provisioned; everything else is auto-discovered. 238 A ring node indicates in its IGP updates the ring LSP signaling 239 protocols it supports. This can be LDP and/or RSVP-TE. Ideally, 240 each node should support both. 242 3.3. Ring Links and Directions 244 Ring links must be MPLS-capable. They are by default unnumbered, 245 point-to-point (from the IGP point of view) and "auto-bundled". The 246 last attribute means that parallel links between ring neighbors are 247 considered as a single link, without the need for explicit 248 configuration for bundling (such as a Link Aggregation Group). Note 249 that each component may be advertised separately in the IGP; however, 250 signaling messages and labels across one component link apply to all 251 components. Parallel links between a pair of ring nodes is often the 252 result of having multiple lambdas or fibers between those nodes. 254 A ring link is not provisioned as belonging to the ring; it is 255 discovered to belong to ring RID if both its adjacent nodes belong to 256 RID. A ring link's direction (CW or AC) is also discovered; this 257 process is initiated by the ring's ring master. Note that the above 258 two attributes can be overridden by provisioning if needed; it is 259 then up to the provisioning system to maintain consistency across the 260 ring. 262 3.3.1. Bypass Links 264 Bypass links are discovered once ring nodes, ring links and 265 directions have been established. As defined earlier, bypass links 266 are links joining non-neighboring ring nodes; often, this may be the 267 result of optically bypassing ring nodes. The use of bypass links 268 will be described in a future version of this document. 270 3.4. Ring LSPs 272 Ring LSPs are not provisioned. Once a ring node R_i knows its RID, 273 its ring links and directions, it kicks off ring LSP signaling 274 automatically. R_i allocates CW and AC labels for each ring LSP 275 RL_k. R_i also initiates the creation of RL_i. As the signaling 276 propagates around the ring, CW and AC labels are exchanged. When R_i 277 receives CW and AC labels for RL_k from its ring neighbors, primary 278 and fast reroute (FRR) paths for RL_k are installed at R_i. More 279 details are given in Section 5. 281 For RSVP-TE LSPs, bandwidths may be signaled in both directions. 282 However, these are not provisioned either; rather, one does "reverse 283 call admission control". When a service needs to use an LSP, the 284 ring node where the traffic enters the ring attempts to increase the 285 bandwidth on the LSP to the egress. If successful, the service is 286 admitted to the ring. 288 3.5. Installing Primary LFIB Entries 290 In setting up RL_k, a node R_j sends out two labels: CL_jk to R_j-1 291 and AL_jk to R_j+1. R_j also receives two labels: CL_j+1,k from 292 R_j+1, and AL_j-1,k from R_j-1. R_j can now set up the forwarding 293 entries for RL_k. In the CW direction, R_j swaps incoming label 294 CL_jk with CL_j+1,k with next hop R_j+1; these allow R_j to act as 295 LSR for RL_k. R_j also installs an LFIB entry to push CL_j+1,k with 296 next hop R_j+1 to act as ingress for RL_k. Similarly, in the AC 297 direction, R_j swaps incoming label AL_jk with AL_j-1,k with next hop 298 R_j-1 (as LSR), and an entry to push AL_j-1,k with next hop R_j-1 (as 299 ingress). 301 Clearly, R_k does not act as ingress for its own LSPs. However, if 302 these LSPs use UHP, then R_k installs LFIB entries to pop CL_k,k for 303 packets received from R_k-1 and to pop AL_k,k for packets received 304 from R_k+1. 306 3.6. Installing FRR LFIB Entries 308 At the same time that R_j sets up its primary CW and AC LFIB entries, 309 it can also set up the protection forwarding entries for RL_k. In 310 the CW direction, R_j sets up an FRR LFIB entry to swap incoming 311 label CL_jk with AL_j-1,k with next hop R_j-1. In the AC direction, 312 R_j sets up an FRR LFIB entry to swap incoming label AL_jk with 313 CL_j+1,k with next hop R_j+1. Again, R_k does not install FRR LFIB 314 entries in this manner. 316 3.7. Protection 318 In this scheme, there are no protection LSPs as such -- no node or 319 link bypasses, no standby LSPs, no detours, and no LFA-type 320 protection. Protection is via the "other" direction around the ring, 321 which is why ring LSPs are in counter-rotating pairs. Protection 322 works in the same way for link, node and ring LSP failures. 324 If a node R_j detects a failure from R_j+1 -- either all links to 325 R_j+1 fail, or R_j+1 itself fails, R_j switches traffic on all CW 326 ring LSPs to the AC direction using the FRR LFIB entries. If the 327 failure is specific to a single ring LSP, R_j switches traffic just 328 for that LSP. In either case, this switchover can be very fast, as 329 the FRR LFIB entries can be preprogrammed. Fast detection and fast 330 switchover lead to minimal traffic loss. 332 R_j then sends an indication to R_j-1 that the CW direction is not 333 working, so that R_j-1 can similarly switch traffic to the AC 334 direction. These indications propagate AC until each traffic source 335 on the ring AC of the failure uses the AC direction. Thus, within a 336 short period, traffic will be flowing in the optimal path, given that 337 there is a failure on the ring. This contrasts with (say) bypass 338 protection, where until the ingress recomputes a new path, traffic 339 will be suboptimal. 341 One point to note is that when a ring node, say R_j, fails, RL_j is 342 clearly unusable. However, the above protection scheme will cause a 343 traffic loop: R_j-1 detects a failure CW, and protects by sending CW 344 traffic on RL_j back all the way to R_j+1, which in turn sends 345 traffic to R_j-1, etc. There are three proposals to avoid this: 347 1. Each ring node acting as ingress sends traffic with a TTL of at 348 most 2*n, where n is the number of nodes in the ring. 350 2. A ring node sends protected traffic (i.e., traffic switched from 351 CW to AC or vice versa) with TTL just large enough to reach the 352 egress. 354 3. A ring node sends protected traffic with a special purpose label 355 below the ring LSP label. A protecting node first checks for the 356 presence of this label; if present, it means that the traffic is 357 looping and MUST be dropped. 359 It is recommended that (2) be implemented. The other methods are 360 optional. 362 4. Autodiscovery 364 4.1. Overview 366 Auto-discovery proceeds in three phases. The first phase is the 367 announcement phase. The second phase is the mastership phase. The 368 third phase is the ring identification phase. 370 S1 371 / \ 372 | R0 . . . R1 R0 has MV = 11 373 | . \ . R1 has MV = 10 374 R7 \________ R2 All other nodes have MV = 00 375 Anti- | . . | 376 clockwise | . Ring . | Clockwise 377 v . RID = 17 . v 378 R6 R3 379 . . 380 R5 . . . R4 381 \ / 382 \ / 383 An 385 Figure 2: Ring with non-ring nodes and links 387 In what follows, we refer to a ring Type-Length-Value (TLV). This is 388 a new TLV that contains an RID and associated flags. A ring link TLV 389 is a ring TLV that appears as a sub-TLV of a traffic engineering TLV 390 (TE TLV) of each link that is identified as a ring link or a bypass 391 link. For IS-IS, the TE TLV is the extended reachability TLV; for 392 OSPF, it is the Link TLV in the opaque TE LSA. A ring node TLV is a 393 ring TLV that appears as a sub-TLV of a "node TLV" once for each ring 394 this node is participating in. In IS-IS, the node TLV is the Router 395 ID TLV; in OSPF, it is a new top-level TLV of the TE LSA. The ring 396 direction field is ignored in ring node TLVs. 398 0 1 2 3 399 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 1 400 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 401 | Type (TBD) | Length = 8 | Ring ID (4 octets) ... | 402 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 403 | ... (RID continued) | Ring Flags (2 octets) | 404 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 406 IS-IS Ring TLV Format 408 0 1 2 3 409 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 1 410 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 411 | Type (TBD) | Length = 12 | 412 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 413 | Ring ID (4 octets) | 414 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 415 | Ring Flags (2 octets) | Pad (2 octets) | 416 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 417 Pad is set to zero when sending and ignored on receipt. 419 OSPF Ring TLV Format 421 0 1 422 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 423 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 424 |MV |RD |SP |OP |M| MBZ | 425 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 426 MV: Mastership Value 427 RD: Ring Direction 428 SP: Signaling Protocols (10 = RSVP-TE; 01 = LDP) 429 OP: OAM Protocols (10 = BFD; 01 = EFM) 430 M : Elected Master (0 = no, 1 = yes) 432 Ring Flags Format 434 4.2. Ring Announcement Phase 436 Each node participating in an MPLS ring is assigned an RID; in the 437 example, RID = 17. A node is also provisioned with a mastership 438 value. Each node advertises a ring node TLV for each ring it is 439 participating in, along with the associated flags. It then starts 440 timer T1. 442 A node in promiscuous mode doesn't advertise any ring node TLVs. If 443 it hears exactly one non-zero RID from its IGP neighbors, it joins 444 that ring, and sends one ring node TLV with that RID. If it hears 445 more than one RID from its IGP neighbors, it doesn't join any rings, 446 and withdraws any ring node TLVs it may have advertised. 448 The announcement phase allows a ring node to discover other ring 449 nodes in the same ring so that a ring master can be elected and ring 450 links be identified. 452 4.3. Mastership Phase 454 When timer T1 fires, a node enters the mastership phase. In this 455 phase, each ring node N starts timer T2 and checks if it is master. 456 If it is the node with the lowest loopback address of all nodes with 457 the highest mastership values, N declares itself master by 458 readvertising its ring node TLV with the M bit set. 460 When timer T2 fires, each node examines the ring node TLVs from all 461 other nodes in the ring to identify the ring master. There should be 462 exaclty one; if not, each node restarts timer T2 and tries again. 463 The nodes that set their M bit should be extra careful in advertising 464 their M bit in subsequent tries. 466 4.4. Ring Identification Phase 468 When there is exactly one ring master M, M enters the Ring 469 Identification Phase. M indicates that it has successfully completed 470 this phase by advertising ring link TLVs. This is the trigger for 471 M's CW neighbor to enter the Ring Identification Phase. This phase 472 passes CW until all ring nodes have completed ring identification. 474 In the Ring Identification Phase, a node X that has two or more IGP 475 neighbors that belong to the ring picks one of them to be its CW ring 476 neighbor. If X is the ring master, it also picks a node as its AC 477 ring neighbor. If there are exactly two such nodes, this step is 478 trivial. If not, X computes a ring that includes all nodes that have 479 completed the Ring Identification Phase (as seen by their ring link 480 TLVs) and further contains the maximal number of nodes that belong to 481 the ring. Based on that, X picks a CW neighbor and inserts ring link 482 TLVs with ring direction CW for each link to its CW neighbor; X also 483 inserts a ring link TLV with direction AC for each link to its AC 484 neighbor. Then, X determines its bypass links. These are links 485 connected to ring nodes that are not ring neighbors. X advertises 486 ring link TLVs for bypass links by setting the link direction to 487 "bypass link". 489 4.5. Ring Changes 491 A future version of this document will specify how ring changes are 492 detected and handled. 494 5. Ring Signaling 496 A future version of this document will specify details about ring LSP 497 signaling. 499 6. Ring OAM 501 Each ring node should advertise in its ring node TLV the OAM 502 protocols it supports. Each ring node is expected to run a link- 503 level OAM over each ring and bypass link. This should be an OAM 504 protocol that both neighbors agree on. The default hello time is 3.3 505 millisecond. 507 Each ring node also sends OAM messages over each direction of its 508 ring LSP. This is a multi-hop OAM to check LSP liveness; typically, 509 BFD would be used for this. The node chooses the hello interval; the 510 default is once a second. 512 7. Security Considerations 514 It is not anticipated that either the notion of MPLS rings or the 515 extensions to various protocols to support them will cause new 516 security loopholes. As this document is updated, this section will 517 also be updated. 519 8. Acknowledgments 521 Many thanks to Pierre Bichon whose exemplar of self-organizing 522 networks and whose urging for ever simpler provisioning led to the 523 notion of promiscuous nodes. 525 9. IANA Considerations 527 There are no requests as yet to IANA for this document. 529 10. References 531 10.1. Normative References 533 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 534 Requirement Levels", BCP 14, RFC 2119, March 1997. 536 10.2. Informative References 538 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 539 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 540 Tunnels", RFC 3209, December 2001. 542 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 543 (TE) Extensions to OSPF Version 2", RFC 3630, September 544 2003. 546 [RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP 547 Specification", RFC 5036, October 2007. 549 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 550 Engineering", RFC 5305, October 2008. 552 Authors' Addresses 554 Kireeti Kompella 555 Juniper Networks, Inc. 556 1194 N. Mathilda Avenue 557 Sunnyvale, CA 94089 558 USA 560 Email: kireeti.kompella@gmail.com 562 Luis M. Contreras 563 Telefonica I+D 564 Ronda de la Comunicacion 565 Sur-3 building, 3rd floor 566 Madrid 28050 567 Spain 569 Email: luismiguel.contrerasmurillo@telefonica.com 570 URI: http://people.tid.es/LuisM.Contreras/