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Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (April 04, 2017) is 2573 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- ** Obsolete normative reference: RFC 3107 (Obsoleted by RFC 8277) == Outdated reference: A later version (-07) exists of draft-ietf-idr-link-bandwidth-06 Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Inter-Domain Routing H. Gredler, Ed. 3 Internet-Draft RtBrick Inc. 4 Intended status: Informational K. Vairavakkalai 5 Expires: October 6, 2017 C. Ramachandran 6 B. Rajagopalan 7 E. Aries 8 Juniper Networks, Inc. 9 L. Fang 10 eBay 11 April 04, 2017 13 Egress Peer Engineering using BGP-LU 14 draft-gredler-idr-bgplu-epe-09 16 Abstract 18 The MPLS source routing paradigm provides path control for both 19 intra- and inter- Autonomous System (AS) traffic. RSVP-TE is 20 utilized for intra-AS path control. This documents outlines how MPLS 21 routers may use the BGP labeled unicast protocol (BGP-LU) for doing 22 traffic-engineering on inter-AS links. 24 Requirements Language 26 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 27 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 28 document are to be interpreted as described in RFC 2119 [RFC2119]. 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at http://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on October 6, 2017. 47 Copyright Notice 49 Copyright (c) 2017 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (http://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 65 2. Motivation, Rationale and Applicability . . . . . . . . . . . 3 66 3. Sample Topology . . . . . . . . . . . . . . . . . . . . . . . 4 67 3.1. Loopback IP addresses and Router-IDs . . . . . . . . . . 4 68 3.2. Link IP addresses . . . . . . . . . . . . . . . . . . . . 5 69 4. Service Route Advertisement . . . . . . . . . . . . . . . . . 5 70 5. Egress Next-hop Advertisement . . . . . . . . . . . . . . . . 5 71 5.1. iBGP meshing and BGP nexthop rewrite policy . . . . . . . 6 72 5.2. Single-hop eBGP . . . . . . . . . . . . . . . . . . . . . 7 73 5.3. Multi-hop eBGP . . . . . . . . . . . . . . . . . . . . . 8 74 5.4. Grouping of Peers . . . . . . . . . . . . . . . . . . . . 9 75 5.5. Supporting Summarization at ASBR . . . . . . . . . . . . 10 76 5.5.1. Locality forwarding bias . . . . . . . . . . . . . . 10 77 5.5.2. Label per group of peers sharing a locality . . . . . 10 78 6. Egress Link Protection . . . . . . . . . . . . . . . . . . . 10 79 6.1. FRR backup routes . . . . . . . . . . . . . . . . . . . . 10 80 6.1.1. Local links . . . . . . . . . . . . . . . . . . . . . 11 81 6.1.2. Remote BGP-LU labels . . . . . . . . . . . . . . . . 11 82 6.1.3. Local IP forwarding tables . . . . . . . . . . . . . 11 83 7. Dynamic link utilization . . . . . . . . . . . . . . . . . . 11 84 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 85 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 86 10. Security Considerations . . . . . . . . . . . . . . . . . . . 12 87 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 88 11.1. Normative References . . . . . . . . . . . . . . . . . . 12 89 11.2. Informative References . . . . . . . . . . . . . . . . . 12 90 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 92 1. Introduction 94 Today, BGP-LU [RFC3107] is used both as an intra-AS 95 [I-D.ietf-mpls-seamless-mpls] and inter-AS routing protocol. BGP-LU 96 may advertise a MPLS transport path between IGP regions and 97 Autonomous Systems. Those paths may span one or more router hops. 98 This document describes advertisement and use of one-hop MPLS label- 99 switched paths (LSPs) for traffic-engineering the links between 100 Autonomous Systems. 102 Consider Figure 1: an ASBR router (R2) advertises a labeled host 103 route for the remote-end IP address of its link (IP3). The BGP next- 104 hop gets set to R2s loopback IP address. For the advertised Label 105 a forwarding action of 'POP and forward' to next-hop (IP3) is 106 installed in R2's MPLS forwarding table. Now consider if R2 had 107 several links and R2 would advertise labels for all of its inter-AS 108 links. By pushing the corresponding MPLS label on the label- 109 stack an ingress router R1 may control the egress peer selection. 111 AS1 : AS2 112 : 113 +----+ iBGP +----+ : eBGP +----+ 114 | R1 |----------| R2 |-IP2----IP3-| R3 | 115 +----+ +----+ : +----+ 116 : 117 -----------traffic-flow----------> 118 <------------route-flow----------- 120 Figure 1: single-hop LSPs 122 Of course, since R1 and R2 may not be directly connected to each 123 other, if the interior routers within AS1 do not maintain routes to 124 external destinations, carrying traffic to such destinations would 125 require a tunnel from R1 to R2. Such tunnel could be realized as 126 either a MPLS Label Switched Path (LSP), or by GRE [RFC2784]. 128 2. Motivation, Rationale and Applicability 130 BGP-LU is often just seen as a 'stitching' protocol for connecting 131 Autonomous Systems. BGP-LU is often not viewed as a viable protocol 132 for solving the Inter-domain traffic-engineering problem. 134 With this document the authors want to clarify the use of BGP-LU for 135 Egress Peering traffic-engineering purposes and encourage both 136 implementers and network operators to use a widely deployed and 137 operationally well understood protocol, rather than inventing new 138 protocols or new extensions to the existing protocols. 140 3. Sample Topology 142 The following topology (Figure 2) and IP addresses shall be used 143 throughout the Egress Peering Engineering advertisement examples. 145 : : 146 AS 1 : AS 2 : AS 4 147 : : 148 : +-----+ : 149 /IP2--:-IP3--|ASBR3| : 150 +-----+ +-----+-IP4--:-IP5--+-----+-----------+-----+ 151 | R1 +-------------+ASBR1| : |ASBR6| 152 +--+--+ +--+--+-IP6--:-IP7--+-----+-----------+-----+ 153 | | \ : |ASBR4| : / 154 | | \ : +-----+ : / 155 | | IP8- --- 156 | | \ ................ / 157 | | IP9- --- 158 | | : \ / : 159 | | : \ / : 160 +--+--+ +--+--+ : +--+--+ : 161 | R2 +-------------+ASBR2|-IP10-:-IP11-|ASBR5| : 162 +-----+ +-----+ : +-----+ : 163 : : 164 : AS3 : 165 : : 167 Figure 2: Sample Topology 169 3.1. Loopback IP addresses and Router-IDs 171 o R1: 192.0.2.1/32 173 o R2: 192.0.2.2/32 175 o ASBR1: 192.0.2.11/32 177 o ASBR2: 192.0.2.12/32 179 o ASBR3: 192.0.2.13/32 181 o ASBR4: 192.0.2.14/32 183 o ASBR5: 192.0.2.15/32 185 o ASBR6: 192.0.2.16/32 187 3.2. Link IP addresses 189 o ASBR1 (203.0.113.2/31) to ASBR3 (203.0.113.3/31) link #1 191 o ASBR1 (203.0.113.4/31) to ASBR3 (203.0.113.5/31) link #2 193 o ASBR1 (203.0.113.6/31) to ASBR4 (203.0.113.7/31) 195 o ASBR1 (203.0.113.8/31) to ASBR5 (203.0.113.9/31) 197 o ASBR2 (203.0.113.10/31) to ASBR5 (203.0.113.11/31) 199 4. Service Route Advertisement 201 In Figure 3 a simple network layout is shown. There are two classes 202 of BGP speakers: 204 1. Ingress Routers 206 2. Controllers 208 Ingress routers receive BGP-LU routes from the ASBRs. Each BGP-LU 209 route corresponds to an egress link. Furthermore Ingress routers 210 receive their service routes using the BGP protocol. The BGP Add- 211 paths extension [I-D.ietf-idr-add-paths] ensures that multiple paths 212 to a given service route may get advertised. 214 As outlined in [I-D.filsfils-spring-segment-routing-central-epe], 215 Controllers receive BGP-LU routes from the ASBRs as well. However 216 the service routes may be received either using the BGP protocol plus 217 the BGP Add-paths extension [I-D.ietf-idr-add-paths] or alternatively 218 The BGP Monitoring protocol [I-D.ietf-grow-bmp] (BMP). BMP has 219 support for advertising the RIB-In of a BGP router. As such it might 220 be a suitable protocol for feeding all potential egress paths of a 221 service-route from a ASBR into a controller. 223 5. Egress Next-hop Advertisement 225 An ASBR assigns a distinct label for each of its next-hops facing an 226 eBGP peer and advertises it to its internal BGP mesh. The ASBR 227 programs a forwarding action 'POP and forward' into the MPLS 228 forwarding table. Note that the neighboring AS is not required to 229 support exchanging NLRIs with the local AS using BGP-LU. It is the 230 local ASBR (ASBR{1,2}) which generates the BGP-LU routes into its 231 iBGP mesh or controller facing session(s). The forwarding next-hop 232 for those routes points to the link-IP addresses of the remote ASBRs 233 (ASBR{3,4,5}). Note that the generated BGP-LU routes always match 234 the BGP next-hop that the remote ASBRs set their BGP service routes 235 to, such that the software component doing route-resolution 236 understands the association between the BGP service route and the 237 BGP-LU forwarding route. 239 5.1. iBGP meshing and BGP nexthop rewrite policy 241 Throughout this document we describe how the BGP next-hop of both BGP 242 Service Routes and BGP-LU routes shall be rewritten. This may clash 243 with existing network deployments and existing network configurations 244 guidelines which may mandate to rewrite the BGP next-hop when an BGP 245 update enters an AS. 247 The Egress peering use case assumes a central controller as shown 248 Figure 3. In order to support both existing BGP nexthop guidelines 249 and the suggestion described in this document, an implementation 250 SHOULD support several internal BGP peer-groups: 252 1. iBGP peer group for Ingress Routers 254 2. iBGP peer group for Controllers 256 The first peer group MAY be left unchanged and use any existing BGP 257 nexthop rewrite policy. The second peer group MUST use the BGP 258 rewrite policy described in this document for both service and BGP-LU 259 routes. 261 Of course a common iBGP peer group and a common rewrite policy may be 262 used if the proposed policy is compatible with existing routing 263 software implementations of BGP next-hop route resolution. 265 +-----------+ 266 | Ingress | 267 | Router | 268 +-----------+ 269 ^ 270 | 271 +-----------+ 272 | BGP | +------------+ 273 | Route |-------------->| Controller | 274 | Reflector | +------------+ 275 +-----------+ ^ 276 ^ ^ | 277 | | | 278 | +-------------------+ | 279 | | | 280 v v v 281 +-----------+ +-----------+ 282 | BGP | | BGP | 283 | ASBR1 | . . . | ASBR2 | 284 +-----------+ +-----------+ 286 Figure 3: Selective iBGP NH rewrite 288 5.2. Single-hop eBGP 290 In Figure 2 the ASBR{1,5} and ASBR{2,5} links are examples for 291 single-hop eBGP advertisements. 293 o ASBR5 advertises a BGP service (SAFI-1) route {172.16/12} to ASBR1 294 with a BGP next-hop of 203.0.113.9. When ASBR1 re-advertises this 295 BGP service route towards its iBGP mesh (R{1,2}) it does not 296 overwrite the BGP next-hop, but rather leaves it unchanged. 298 o ASBR1 advertises a BGP-LU route {203.0.113.9/32, label 100} with a 299 BGP next hop of 192.0.2.11. ASBR1 programs a MPLS forwarding 300 state of 'POP and forward' to 203.0.113.9 for the advertised label 301 100. 303 o ASBR5 advertises a BGP service (SAFI-1) route {172.16/12} to ASBR2 304 with a BGP next-hop of 203.0.113.11. When ASBR2 re-advertises 305 this BGP service route towards its iBGP mesh (R{1,2}) it does not 306 overwrite the BGP next-hop, but rather leaves it unchanged. 308 o ASBR2 advertises BGP-LU route {203.0.113.11/32, label 101} with a 309 BGP next hop of 192.0.2.12. ASBR2 programs a MPLS forwarding 310 state of 'POP and forward' to 203.0.113.11 for the advertised 311 label 101. 313 o Should the operator already be redistributing egress links into 314 the network for purposes of BGP next-hop resolution, the BGP-LU 315 route {203.0.113.9/32, label 100} will now take precedence due to 316 LPM over the previous redistributed prefix {203.0.113.8/31}. If 317 the BGP next-hop prefix {203.0.113.9/32} were to be redistributed 318 as-is, then standard protocol best-path and preference selection 319 mechanisms will be exhausted in order to select the best-path. 321 o In general, ASBR1 may receive advertisements for the route to 322 172.16/12 from ASBR3 and ASBR4, as well as from ASBR5. One of 323 these other advertisements may be chosen as the best path by the 324 BGP decision process. In order to allow ASBR1 to re-advertise the 325 route to 172.16/12 received from ASBR5 with next-hop 203.0.113.9, 326 independent of the other advertisements received, ASBR1 and R{1,2} 327 need to support the BGP add-paths extension. 328 [I-D.ietf-idr-add-paths]. 330 5.3. Multi-hop eBGP 332 Todays operational practice for load-sharing across parallel links is 333 to configure a single multi-hop eBGP session between a pair of 334 routers. The IP addresses for the Multi-hop eBGP session are 335 typically sourced from the loopback IP interfaces. Note that those 336 IP addresses do not share an IP subnet. Most often those loopback IP 337 addresses are most specific host routes. Since the BGP next-hops of 338 the received BGP service routes are typically rewritten to the remote 339 routers loopback IP address they cannot get immediatly resolved by 340 the receiving router. To overcome this, the operator configures a 341 static route with next-hops pointing to each of the remote-IP 342 addresses of the underlying links. 344 In Figure 2 both ASBR{1,3} links are examples of a multi-hop eBGP 345 advertisement. In order to advertise a distinct label for a common 346 FEC throughout the iBGP mesh, ASBR1 and all the receiving iBGP 347 routers need to support the BGP Add-paths extension. 348 [I-D.ietf-idr-add-paths]. 350 o ASBR3 advertises a BGP service (SAFI-1) route {172.16/12} over 351 multi-hop eBGP to ASBR1 with a BGP next-hop of 192.0.2.13. When 352 ASBR1 re-advertises this BGP service route towards its iBGP mesh 353 (R{1,2}) it does not overwrite the BGP next-hop, but rather leaves 354 it unchanged. Note that the iBGP routers SHOULD support the BGP 355 Add-paths extension [I-D.ietf-idr-add-paths] such that ASBR can 356 re-advertise all paths to the SAFI-1 route {172.16/12}. 358 o For link #1, ASBR1 advertises into its iBGP mesh a BGP-LU route 359 {192.0.2.13/32, label 102} with a BGP next hop of 192.0.2.11. To 360 differentiate this from the link #2 route-advertisement (which 361 contains the same FEC) it is setting the path-ID to 1. ASBR1 362 programs a MPLS forwarding state of 'POP and forward' to 363 203.0.113.3 for the advertised label 102. 365 o For link #2, ASBR1 advertises into its iBGP mesh a BGP-LU route 366 {192.0.2.13/32, label 103} with a BGP next hop of 192.0.2.11. To 367 differentiate this from the link #1 route-advertisement (which 368 contains the same FEC) it is setting the path-ID to 2. ASBR1 369 programs a MPLS forwarding state of 'POP and forward' to 370 203.0.113.5 for the advertised label 103. 372 o Should the operator already be redistributing static routes into 373 the network, the BGP next-hop {192.0.2.13} may already be 374 resolvable. It is then that standard protocol best-path and 375 preference selection mechanisms will be exhausted in order to 376 select the best-path. 378 5.4. Grouping of Peers 380 In addition to offering a distinct BGP-LU label for each egress link, 381 an ASBR MAY want to advertise a BGP-LU label which represents a load- 382 balancing forwarding action across a set of peers. The difference is 383 here that the ingress node gives up individual link control, but 384 rather delegates the load-balancing decision to a particular egress 385 router which has the freedom to send the traffic down to any link in 386 the Peer Set as identified by the BGP-LU label. 388 Assume that ASBR1 wants to advertise a label identifying the Peer Set 389 {ASBR3, ASBR4, ASBR5}. 391 o For the two ASBR{1,3} links in Figure 2, belonging to Peer Set 1, 392 ASBR1 advertises a single BGP-LU route {192.0.2.13/32, label 104} 393 with a BGP next hop of 192.0.2.11. To differentiate this from the 394 ASBR{1,3} single link route-advertisements (which contains the 395 same FEC) it is setting the path-ID to 3 and attaching a Peer-Set 396 Community 'Peer Set 1'. 398 o For the ASBR{1,4} link in Figure 2, ASBR1 advertises a BGP-LU 399 route {203.0.113.7/32, label 104} with a BGP next hop of 400 192.0.2.11. To differentiate this from the ASBR{1,4} single link 401 route-advertisements (which contains the same FEC) it is setting 402 the path-ID to 2 and attaching a Peer-Set Community 'Peer Set 1'. 404 o For the ASBR{1,5} link in Figure 2, ASBR1 advertises a BGP-LU 405 route {203.0.113.9/32, label 104} with a BGP next hop of 406 192.0.2.11. To differentiate this from the ASBR{1,5} single link 407 route-advertisements (which contains the same FEC) it is setting 408 the path-ID to 2 and attaching a Peer-Set Community 'Peer Set 1'. 410 Finally ASBR1 programs a MPLS forwarding state of 'POP and load- 411 balance' to {203.0.113.3, 203.0.113.5, 203.0.113.7, 203.0.113.9} for 412 the advertised label 104. 414 5.5. Supporting Summarization at ASBR 416 5.5.1. Locality forwarding bias 418 A router has one or more forwarding plane units. A forwarding plane 419 unit consists of one or more interfaces. Forwarding of packets to an 420 interface that is member of a forwarding plane unit is cheaper than 421 across units. 423 A route entry in the forwarding-table may contain multiple next-hops, 424 each pointing to a network-interface. When forwarding a packet, a 425 forwarding plane unit may optionally provide preference to a subset 426 of these next-hops, whose interfaces are its own members. This 427 behavior is called "Locality forwarding bias". 429 5.5.2. Label per group of peers sharing a locality 431 An ASBR MAY assign a distinct label for the set of eBGP-peers that 432 share a forwarding plane unit and advertise it to its internal BGP 433 mesh. The ASBR programs a forwarding action 'POP and IP-lookup' into 434 the MPLS forwarding table for these labels. While performing the IP- 435 lookup, the ASBR MUST perform "Locality-forwarding bias" to ensure it 436 only selects next-hops towards eBGP peers that are attached to the 437 current forwarding plane unit, where the IP-lookup is happening. 439 This provides the ingress-peers with ability to steer traffic towards 440 a "subset of eBGP-peers" attached to an ASBR, while preserving the 441 ability of the ASBR to aggregate the IP prefixes received from those 442 eBGP-peers, while re-advertising to the internal BGP mesh. 444 6. Egress Link Protection 446 It is desirable to provide a local-repair based protection scheme, in 447 case a redundant path is available to reach a peer AS. Protection 448 may be applied at multiple levels in the routing stack. Since the 449 ASBR has insight into both BGP-LU and BGP service advertisements, 450 protection can be provided at the BGP-LU, at the BGP service or both 451 levels. 453 6.1. FRR backup routes 455 Assume the network operator wants to provide a local-repair next-hop 456 for the 172.16/12 BGP service route at ASBR1. The active route 457 resolves over the parallel links towards ASBR3. In case the link #1 458 between ASBR{1,3} fails there are now several candidate backup paths 459 providing protection against link or node failure. 461 6.1.1. Local links 463 Assuming that the remaining link #2 between ASBR{1,3} has enough 464 capacity, and link-protection is sufficient, this link MAY serve as 465 temporary backup. 467 However if node-protection or additional capacity is desired, then 468 the local link between ASBR{1,4} or ASBR{1,5} MAY be used as 469 temporary backup. 471 6.1.2. Remote BGP-LU labels 473 ASBR1 is both originator and receiver of BGP routing information. 474 For this protection method it is required that the ASBRs support the 475 [I-D.ietf-idr-best-external] behavior. ASBR1 receives both the BGP- 476 LU and BGP service routes from ASBR2 and therefore can use the ASBR2 477 advertised label as a backup path given that ASBR1 has a tunnel 478 towards ASBR2. 480 6.1.3. Local IP forwarding tables 482 For protecting plain unicast (Internet) routing information a very 483 simple backup scheme could be to recurse to the relevant IP 484 forwarding table and do an IP lookup to further determine a new 485 egress link. 487 7. Dynamic link utilization 489 For a software component which controls the egress link selection it 490 may be desirable to know about a particular egress links current 491 utilization, such that it can adjust the traffic that gets sent to a 492 particular interface. 494 In [I-D.ietf-idr-link-bandwidth] a community for reporting link- 495 bandwidth is specified. Rather than reporting the static bandwidth 496 of the link, the ASBRs shall report the available bandwidth as seen 497 by the data-plane via the link-bandwidth community in their BGP-LU 498 update message. 500 It is crucial that ingress routers learn quickly about congestion of 501 an egress link and hence it is desired to get timely updates of the 502 advertised per-link BGP-LU routes carrying the available bandwidth 503 information when the available bandwidth crosses a certain 504 (preconfigured) threshold. 506 Controllers may also utilize the link-bandwidth community among other 507 common mechanisms to retrieve data-plane statistics (e.g. SNMP, 508 NETCONF) 510 8. Acknowledgements 512 Many thanks to Yakov Rekhter, Chris Bowers and Jeffrey (Zhaohui) 513 Zhang for their detailed review and insightful comments. 515 Special thanks to Richard Steenbergen and Tom Scholl who brought up 516 the original idea of using MPLS for BGP based egress load-balancing 517 at their inspiring talk at Nanog 48. 519 9. IANA Considerations 521 This documents does not request any action from IANA. 523 10. Security Considerations 525 This document does not introduce any change in terms of BGP security. 527 11. References 529 11.1. Normative References 531 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 532 Requirement Levels", BCP 14, RFC 2119, 533 DOI 10.17487/RFC2119, March 1997, 534 . 536 [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. 537 Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, 538 DOI 10.17487/RFC2784, March 2000, 539 . 541 [RFC3107] Rekhter, Y. and E. Rosen, "Carrying Label Information in 542 BGP-4", RFC 3107, DOI 10.17487/RFC3107, May 2001, 543 . 545 11.2. Informative References 547 [I-D.filsfils-spring-segment-routing-central-epe] 548 Filsfils, C., Previdi, S., Patel, K., Shaw, S., Ginsburg, 549 D., and D. Afanasiev, "Segment Routing Centralized Egress 550 Peer Engineering", draft-filsfils-spring-segment-routing- 551 central-epe-05 (work in progress), August 2015. 553 [I-D.ietf-grow-bmp] 554 Scudder, J., Fernando, R., and S. Stuart, "BGP Monitoring 555 Protocol", draft-ietf-grow-bmp-17 (work in progress), 556 January 2016. 558 [I-D.ietf-idr-add-paths] 559 Walton, D., Retana, A., Chen, E., and J. Scudder, 560 "Advertisement of Multiple Paths in BGP", draft-ietf-idr- 561 add-paths-15 (work in progress), May 2016. 563 [I-D.ietf-idr-best-external] 564 Marques, P., Fernando, R., Chen, E., Mohapatra, P., and H. 565 Gredler, "Advertisement of the best external route in 566 BGP", draft-ietf-idr-best-external-05 (work in progress), 567 January 2012. 569 [I-D.ietf-idr-link-bandwidth] 570 Mohapatra, P. and R. Fernando, "BGP Link Bandwidth 571 Extended Community", draft-ietf-idr-link-bandwidth-06 572 (work in progress), January 2013. 574 [I-D.ietf-mpls-seamless-mpls] 575 Leymann, N., Decraene, B., Filsfils, C., Konstantynowicz, 576 M., and D. Steinberg, "Seamless MPLS Architecture", draft- 577 ietf-mpls-seamless-mpls-07 (work in progress), June 2014. 579 Authors' Addresses 581 Hannes Gredler (editor) 582 RtBrick Inc. 584 Email: hannes@rtbrick.com 586 Kaliraj Vairavakkalai 587 Juniper Networks, Inc. 588 1194 N. Mathilda Ave. 589 Sunnyvale, CA 94089 590 US 592 Email: kaliraj@juniper.net 593 Chandra Ramachandran 594 Juniper Networks, Inc. 595 Electra, Exora Business Park Marathahalli - Sarjapur Outer Ring Road 596 Bangalore, KA 560103 597 India 599 Email: csekar@juniper.net 601 Balaji Rajagopalan 602 Juniper Networks, Inc. 603 Electra, Exora Business Park Marathahalli - Sarjapur Outer Ring Road 604 Bangalore, KA 560103 605 India 607 Email: balajir@juniper.net 609 Ebben Aries 610 Juniper Networks, Inc. 611 1194 N. Mathilda Ave. 612 Sunnyvale, CA 94089 613 US 615 Email: earies@juniper.net 617 Luyuan Fang 618 eBay 619 411 108th Ave NE 620 Bellevue, WA 98004 621 US 623 Email: lufang@ebay.com