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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 BESS Working Group S. Litkowski 3 Internet-Draft S. Agrawal 4 Intended status: Standards Track K. Ananthamurthy 5 Expires: July 20, 2020 Cisco 6 K. Patel 7 Arrcus 8 January 17, 2020 10 Advertising IPv4 Network Layer Reachability Information with an IPv6 11 Next Hop 12 draft-ietf-bess-rfc5549revision-01 14 Abstract 16 Multiprotocol BGP (MP-BGP) [RFC4760] specifies that the set of usable 17 next-hop address families is determined by the Address Family 18 Identifier (AFI) and the Subsequent Address Family Identifier (SAFI). 19 The current AFI/SAFI definitions for the IPv4 address family only 20 have provisions for advertising a Next Hop address that belongs to 21 the IPv4 protocol when advertising IPv4 Network Layer Reachability 22 Information (NLRI) or VPN-IPv4 NLRI. This document specifies the 23 extensions necessary to allow advertising IPv4 NLRI or VPN-IPv4 NLRI 24 with a Next Hop address that belongs to the IPv6 protocol. This 25 comprises an extension of the AFI/SAFI definitions to allow the 26 address of the Next Hop for IPv4 NLRI or VPN-IPv4 NLRI to also belong 27 to the IPv6 protocol, the encoding of the Next Hop to determine which 28 of the protocols the address actually belongs to, and a new BGP 29 Capability allowing MP-BGP Peers to dynamically discover whether they 30 can exchange IPv4 NLRI and VPN-IPv4 NLRI with an IPv6 Next Hop. 32 Status of This Memo 34 This Internet-Draft is submitted in full conformance with the 35 provisions of BCP 78 and BCP 79. 37 Internet-Drafts are working documents of the Internet Engineering 38 Task Force (IETF). Note that other groups may also distribute 39 working documents as Internet-Drafts. The list of current Internet- 40 Drafts is at https://datatracker.ietf.org/drafts/current/. 42 Internet-Drafts are draft documents valid for a maximum of six months 43 and may be updated, replaced, or obsoleted by other documents at any 44 time. It is inappropriate to use Internet-Drafts as reference 45 material or to cite them other than as "work in progress." 47 This Internet-Draft will expire on July 20, 2020. 49 Copyright Notice 51 Copyright (c) 2020 IETF Trust and the persons identified as the 52 document authors. All rights reserved. 54 This document is subject to BCP 78 and the IETF Trust's Legal 55 Provisions Relating to IETF Documents 56 (https://trustee.ietf.org/license-info) in effect on the date of 57 publication of this document. Please review these documents 58 carefully, as they describe your rights and restrictions with respect 59 to this document. Code Components extracted from this document must 60 include Simplified BSD License text as described in Section 4.e of 61 the Trust Legal Provisions and are provided without warranty as 62 described in the Simplified BSD License. 64 Table of Contents 66 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 67 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4 68 3. Extension of AFI/SAFI Definitions for the IPv4 Address Family 4 69 4. Use of BGP Capability Advertisement . . . . . . . . . . . . . 6 70 5. Operations . . . . . . . . . . . . . . . . . . . . . . . . . 8 71 6. Usage Examples . . . . . . . . . . . . . . . . . . . . . . . 8 72 6.1. IPv4 over IPv6 Core . . . . . . . . . . . . . . . . . . . 8 73 6.2. IPv4 VPN unicast over IPv6 Core . . . . . . . . . . . . . 9 74 6.3. IPv4 VPN multicast over IPv6 Core . . . . . . . . . . . . 9 75 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 76 8. Security Considerations . . . . . . . . . . . . . . . . . . . 10 77 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10 78 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 79 10.1. Normative References . . . . . . . . . . . . . . . . . . 10 80 10.2. Informative References . . . . . . . . . . . . . . . . . 11 81 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 83 1. Introduction 85 Multiprotocol BGP (MP-BGP) [RFC4760] specifies that the set of 86 network-layer protocols to which the address carried in the Next Hop 87 field may belong is determined by the Address Family Identifier (AFI) 88 and the Subsequent Address Family Identifier (SAFI). A number of 89 existing AFI/SAFIs allow the Next Hop address to belong to a 90 different address family than the Network Layer Reachability 91 Information (NLRI). For example, the AFI/SAFI <25/65> used (as per 92 [RFC6074]) to perform L2VPN auto-discovery, allows advertising NLRI 93 that contains the identifier of a Virtual Private LAN Service (VPLS) 94 instance or that identifies a particular pool of attachment circuits 95 at a given Provider Edge (PE), while the Next Hop field contains the 96 loopback address of a PE. Similarly, the AFI/SAFI <1/132> (defined 97 in [RFC4684]) to advertise Route Target (RT) membership information, 98 allows advertising NLRI that contains such RT membership information, 99 while the Next Hop field contains the address of the advertising 100 router. 102 Furthermore, a number of these existing AFI/SAFIs allow the Next Hop 103 to belong to either the IPv4 Network Layer Protocol or the IPv6 104 Network Layer Protocol, and specify the encoding of the Next Hop 105 information to determine which of the protocols the address actually 106 belongs to. For example, [RFC4684] allows the Next Hop address to be 107 either IPv4 or IPv6 and states that the Next Hop field address shall 108 be interpreted as an IPv4 address whenever the length of Next Hop 109 address is 4 octets, and as an IPv6 address whenever the length of 110 the Next Hop address is 16 octets. 112 There are situations such as those described in [RFC4925] and in 113 [RFC5565] where carriers (or large enterprise networks acting as 114 carrier for their internal resources) may be required to establish 115 connectivity between 'islands' of networks of one address family type 116 across a transit core of a differing address family type. This 117 includes both the case of IPv6 islands across an IPv4 core and the 118 case of IPv4 islands across an IPv6 core. Where Multiprotocol BGP 119 (MP-BGP) is used to advertise the corresponding reachability 120 information, this translates into the requirement for a BGP speaker 121 to advertise Network Layer Reachability Information (NLRI) of a given 122 address family via a Next Hop of a different address family (i.e., 123 IPv6 NLRI with IPv4 Next Hop and IPv4 NLRI with IPv6 Next Hop). 125 The current AFI/SAFI definitions for the IPv6 address family assume 126 that the Next Hop address belongs to the IPv6 address family type. 127 Specifically, as per [RFC2545] and [RFC8277], when the is 128 <2/1>, <2/2>, or <2/4>, the Next Hop address is assumed to be of IPv6 129 type. As per [RFC4659], when the is <2/128>, the Next Hop 130 address is assumed to be of IPv6-VPN type. 132 However, [RFC4798] and [RFC4659] specify how an IPv4 address can be 133 encoded inside the Next Hop IPv6 address field when IPv6 NLRI needs 134 to be advertised with an IPv4 Next Hop. [RFC4798] defines how the 135 IPv4-mapped IPv6 address format specified in the IPv6 addressing 136 architecture ([RFC4291]) can be used for that purpose when the is <2/1>, <2/2>, or <2/4>. [RFC4659] defines how the IPv4- 138 mapped IPv6 address format as well as a null Route Distinguisher can 139 be used for that purpose when the is <2/128>. Thus, there 140 are existing solutions for the advertisement of IPv6 NLRI with an 141 IPv4 Next Hop. 143 Similarly, the current AFI/SAFI definitions for advertisement of IPv4 144 NLRI or VPN-IPv4 NLRI assume that the Next Hop address belongs to the 145 IPv4 address family type. Specifically, as per [RFC4760] and 146 [RFC8277], when the is <1/1>, <1/2>, or <1/4>, the Next 147 Hop address is assumed to be of IPv4 type. As per [RFC4364], when 148 the is <1/128>, the Next Hop address is assumed to be of 149 VPN-IPv4 type. As per [RFC6513] and [RFC6514], when the 150 is <1/129>, the Next Hop address is assumed to be of VPN-IPv4 type. 151 There is clearly no generally applicable method for encoding an IPv6 152 address inside the IPv4 address field of the Next Hop. Hence, there 153 is currently no specified solution for advertising IPv4 or VPN-IPv4 154 NLRI with an IPv6 Next Hop. 156 This document specifies the extensions necessary to do so. This 157 comprises an extension of the AFI/SAFI definitions to allow the 158 address of the Next Hop for IPv4 NLRI or VPN-IPv4 NLRI to belong to 159 either the IPv4 or the IPv6 protocol, the encoding of the Next Hop 160 information to determine which of the protocols the address actually 161 belongs to, and a new BGP Capability allowing MP-BGP peers to 162 dynamically discover whether they can exchange IPv4 NLRI and VPN- 163 IPv4 NLRI with an IPv6 Next Hop. The new BGP Capability allows 164 gradual deployment of the new functionality of advertising IPv4 165 reachability via an IPv6 Next Hop, without any flag day nor any risk 166 of traffic black-holing. 168 2. Requirements Language 170 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 171 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 172 "OPTIONAL" in this document are to be interpreted as described in BCP 173 14 [RFC2119] [RFC8174] when, and only when, they appear in all 174 capitals, as shown here. 176 3. Extension of AFI/SAFI Definitions for the IPv4 Address Family 178 As mentioned earlier, MP-BGP specifies that the set of usable next- 179 hop address families is determined by the Address Family Identifier 180 (AFI) and the Subsequent Address Family Identifier (SAFI). The 181 following current AFI/SAFI definitions for the IPv4 NLRI or VPN-IPv4 182 NLRI (<1/1>, <1/2>, <1/4>, <1/128> and <1/129>) only have provisions 183 for advertising a Next Hop address that belongs to the IPv4 protocol. 184 This document extends the definition of the AFI/SAFI for 185 advertisement of IPv4 NLRI and VPN-IPv4 NLRI to extend the set of 186 usable next-hop address families to include IPv6 in addition to IPv4. 188 Specifically, this document allows advertising with [RFC4760] of an 189 MP_REACH_NLRI with: 191 o AFI = 1 192 o SAFI = 1, 2, or 4 194 o Length of Next Hop Address = 16 or 32 196 o Next Hop Address = IPv6 address of next hop (potentially followed 197 by the link-local IPv6 address of the next hop). This field is to 198 be constructed as per Section 3 of [RFC2545]. 200 o NLRI= NLRI as per current AFI/SAFI definition 202 It also allows advertising with [RFC4760] of an MP_REACH_NLRI with: 204 o AFI = 1 206 o SAFI = 128 or 129 208 o Length of Next Hop Address = 24 or 48 210 o Next Hop Address = VPN-IPv6 address of next hop with an 8-octet RD 211 is set to zero (potentially followed by the link-local VPN-IPv6 212 address of the next hop with an 8-octet RD is set to zero). 214 o NLRI= NLRI as per current AFI/SAFI definition 216 This is in addition to the current mode of operation allowing 217 advertisement of NLRI for of <1/1>, <1/2> and <1/4> with a 218 next hop address of IPv4 type and advertisement of NLRI for of <1/128> and <1/129> with a next hop address of VPN-IPv4 220 type. 222 The BGP speaker receiving the advertisement MUST use the Length of 223 Next Hop Address field to determine which network-layer protocol the 224 next hop address belongs to. 226 o When the AFI/SAFI is <1/1>, <1/2> or <1/4> and when the Length of 227 Next Hop Address field is equal to 16 or 32, the next hop address 228 is of type IPv6. 230 o When the AFI/SAFI is <1/128>, or <1/129> and when the Length of 231 Next Hop Address field is equal to 24 or 48, the next hop address 232 is of type VPN-IPv6. 234 Note that this method of using the Length of the Next Hop Address 235 field to determine which network-layer protocol the next hop address 236 belongs to (out of the set of protocols allowed by the AFI/SAFI 237 definition) is the same as used in [RFC4684] and [RFC6074]. 239 4. Use of BGP Capability Advertisement 241 [RFC5492] defines a mechanism to allow two BGP speakers to discover 242 if a particular capability is supported by their BGP peer and thus 243 whether it can be used with that peer. This document defines a new 244 capability that can be advertised using [RFC5492] and that is 245 referred to as the Extended Next Hop Encoding capability. This 246 capability allows BGP speakers to discover whether, for a given NLRI 247 , a peer supports advertisement with a next hop whose 248 network protocol is determined by the value of the Length of Next Hop 249 Address field, as specified in Section 3. 251 A BGP speaker that wishes to advertise to a BGP peer an IPv6 Next Hop 252 for IPv4 NLRI or for VPN-IPv4 NLRI as per this specification MUST use 253 the Capability Advertisement procedures defined in [RFC5492] with the 254 Extended Next Hop Encoding Capability to determine whether its peer 255 supports this for the NLRI AFI/SAFI pair(s) of interest. The fields 256 in the Capabilities Optional Parameter MUST be set as follows: 258 o The Capability Code field MUST be set to 5 (which indicates the 259 Extended Next Hop Encoding capability). 261 o The Capability Length field is set to a variable value that is the 262 length of the Capability Value field (which follows). 264 o The Capability Value field has the following format: 266 +-----------------------------------------------------+ 267 | NLRI AFI - 1 (2 octets) | 268 +-----------------------------------------------------+ 269 | NLRI SAFI - 1 (2 octets) | 270 +-----------------------------------------------------+ 271 | Nexthop AFI - 1 (2 octets) | 272 +-----------------------------------------------------+ 273 | ..... | 274 +-----------------------------------------------------+ 275 | NLRI AFI - N (2 octets) | 276 +-----------------------------------------------------+ 277 | NLRI SAFI - N (2 octets) | 278 +-----------------------------------------------------+ 279 | Nexthop AFI - N (2 octets) | 280 +-----------------------------------------------------+ 282 where: 284 * each triple indicates that 285 NLRI of may be advertised with a Next 286 Hop address belonging to the network-layer protocol of Nexthop 287 AFI. 289 * the AFI and SAFI values are defined in the Address Family 290 Identifier and Subsequent Address Family Identifier registries 291 maintained by IANA. 293 Since this document only concerns itself with the advertisement of 294 IPv4 NLRI and VPN-IPv4 NLRI with an IPv6 Next Hop, this specification 295 only allows the following values in the Capability Value field of the 296 Extended Next Hop Encoding capability: 298 o NLRI AFI = 1 (IPv4) 300 o NLRI SAFI = 1, 2, 4, 128 or 129 302 o Nexthop AFI = 2 (IPv6) 304 This specification does not propose that the Extended Next Hop 305 Encoding capability be used with any other combinations of . In particular, this specification does not 307 propose that the Extended Next Hop Encoding capability be used for 308 NLRI AFI/SAFIs whose definition already allows use of both IPv4 and 309 IPv6 next hops (e.g., AFI/SAFI = <1/132> as defined in [RFC4684]). 310 Similarly, it does not propose that the Extended Next Hop Encoding 311 capability be used for NLRI AFI/SAFIs for which there is already a 312 solution for advertising a next hop of a different address family 313 (e.g., AFI/SAFI = <2/1>, <2/2>, or <2/4> with IPv4 Next Hop as per 314 [RFC4798] and AFI/SAFI = <2/128> with IPv4 Next Hop as per 315 [RFC4659]). 317 It is expected that if new AFI/SAFIs are defined in the future, their 318 definition will have provisions (where appropriate) for both IPv4 and 319 IPv6 Next Hops from the onset, with determination based on Length of 320 Next Hop Address field. Thus, new AFI/SAFIs are not expected to make 321 use of the Extended Next Hop Encoding capability. 323 A BGP speaker MUST only advertise to a BGP peer the IPv4 or VPN-IPv4 324 NLRI with an IPv6 Next Hop if the BGP speaker has first ascertained 325 via BGP Capability Advertisement that the BGP peer supports the 326 Extended Next Hop Encoding capability for the relevant AFI/SAFI pair. 328 The Extended Next Hop Encoding capability provides information about 329 next hop encoding for a given AFI/SAFI, assuming that AFI/SAFI is 330 allowed. It does not influence whether that AFI/SAFI is indeed 331 allowed. Whether a AFI/SAFI can be used between the BGP peers is 332 purely determined through the Multiprotocol Extensions capability 333 defined in [RFC4760]. 335 The Extended Next Hop Encoding capability MAY be dynamically updated 336 through the use of the Dynamic Capability capability and associated 337 mechanisms defined in [I-D.ietf-idr-dynamic-cap]. 339 5. Operations 341 By default, if a particular BGP session is running over IPvx (where 342 IPvx is IPv4 or IPv6), and if the BGP speaker sending an update is 343 putting its own address in as the next hop, then the next hop address 344 SHOULD be specified as an IPvx address, using the encoding rules 345 specified in the AFI/SAFI definition of the NLRI being updated. This 346 default behavior may be overridden by policy. 348 When a next hop address needs to be passed along unchanged (e.g., as 349 a Route Reflector (RR) would do), its encoding MUST NOT be changed. 350 If a particular RR client cannot handle that encoding (as determined 351 by the BGP Capability Advertisement), then the NLRI in question 352 cannot be distributed to that client. For sound routing in certain 353 scenarios, this will require that all the RR clients be able to 354 handle whatever encodings any of them may generate. 356 6. Usage Examples 358 6.1. IPv4 over IPv6 Core 360 The extensions defined in this document may be used as discussed in 361 [RFC5565] for the interconnection of IPV4 islands over an IPv6 362 backbone. In this application, Address Family Border Routers (AFBRs; 363 as defined in [RFC4925]) advertise IPv4 NLRI in the MP_REACH_NLRI 364 along with an IPv6 Next Hop. 366 The MP_REACH_NLRI is encoded with: 368 o AFI = 1 370 o SAFI = 1 372 o Length of Next Hop Network Address = 16 (or 32) 374 o Network Address of Next Hop = IPv6 address of Next Hop 376 o NLRI = IPv4 routes 378 During BGP Capability Advertisement, the PE routers would include the 379 following fields in the Capabilities Optional Parameter: 381 o Capability Code set to "Extended Next Hop Encoding" 383 o Capability Value containing 386 6.2. IPv4 VPN unicast over IPv6 Core 388 The extensions defined in this document may be used for support of 389 IPV4 VPNs over an IPv6 backbone. In this application, PE routers 390 would advertise VPN-IPv4 NLRI in the MP_REACH_NLRI along with an IPv6 391 Next Hop. 393 The MP_REACH_NLRI is encoded with: 395 o AFI = 1 397 o SAFI = 128 399 o Length of Next Hop Network Address = 24 (or 48) 401 o Network Address of Next Hop = VPN-IPv6 address of Next Hop whose 402 RD is set to zero 404 o NLRI = IPv4-VPN routes 406 During BGP Capability Advertisement, the PE routers would include the 407 following fields in the Capabilities Optional Parameter: 409 o Capability Code set to "Extended Next Hop Encoding" 411 o Capability Value containing 414 6.3. IPv4 VPN multicast over IPv6 Core 416 The extensions defined in this document may be used for support of 417 IPV4 multicast VPNs over an IPv6 backbone. In this application, PE 418 routers would advertise VPN-IPv4 NLRI in the MP_REACH_NLRI along with 419 an IPv6 Next Hop. 421 The MP_REACH_NLRI is encoded with: 423 o AFI = 1 425 o SAFI = 129 427 o Length of Next Hop Network Address = 24 (or 48) 428 o Network Address of Next Hop = VPN-IPv6 address of Next Hop whose 429 RD is set to zero 431 o NLRI = IPv4-VPN routes 433 During BGP Capability Advertisement, the PE routers would include the 434 following fields in the Capabilities Optional Parameter: 436 o Capability Code set to "Extended Next Hop Encoding" 438 o Capability Value containing 441 7. IANA Considerations 443 This document defines, in Section 4, a new Capability Code to 444 indicate the Extended Next Hop Encoding capability in the [RFC5492] 445 Capabilities Optional Parameter. The value for this new Capability 446 Code is 5, which is in the range set aside for allocation using the 447 "IETF Review" policy defined in [RFC5226]. 449 8. Security Considerations 451 This document does not raise any additional security issues beyond 452 those of BGP-4 and the Multiprotocol extensions for BGP-4. The same 453 security mechanisms are applicable. 455 Although not expected to be the typical case, the IPv6 address used 456 as the BGP Next Hop Address could be an IPv4-mapped IPv6 address (as 457 defined in [RFC4291]). Configuration of the security mechanisms 458 potentially deployed by the network operator (such as security checks 459 on next hop address) need to keep this case in mind also. 461 9. Acknowledgments 463 The authors would like to thank Francois Le Faucheur and Eric Rosen 464 for the edition and their work on [RFC5549]. 466 The authors would like to thank Yakov Rekhter, Pranav Mehta, and John 467 Scudder for their contributions to the approach defined in [RFC5549]. 469 10. References 471 10.1. Normative References 473 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 474 Requirement Levels", BCP 14, RFC 2119, 475 DOI 10.17487/RFC2119, March 1997, 476 . 478 [RFC2545] Marques, P. and F. Dupont, "Use of BGP-4 Multiprotocol 479 Extensions for IPv6 Inter-Domain Routing", RFC 2545, 480 DOI 10.17487/RFC2545, March 1999, 481 . 483 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 484 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 485 2006, . 487 [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private 488 Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February 489 2006, . 491 [RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, 492 "Multiprotocol Extensions for BGP-4", RFC 4760, 493 DOI 10.17487/RFC4760, January 2007, 494 . 496 [RFC5492] Scudder, J. and R. Chandra, "Capabilities Advertisement 497 with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February 498 2009, . 500 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 501 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 502 May 2017, . 504 [RFC8277] Rosen, E., "Using BGP to Bind MPLS Labels to Address 505 Prefixes", RFC 8277, DOI 10.17487/RFC8277, October 2017, 506 . 508 10.2. Informative References 510 [I-D.ietf-idr-dynamic-cap] 511 Ramachandra, S. and E. Chen, "Dynamic Capability for BGP- 512 4", draft-ietf-idr-dynamic-cap-14 (work in progress), 513 December 2011. 515 [RFC4659] De Clercq, J., Ooms, D., Carugi, M., and F. Le Faucheur, 516 "BGP-MPLS IP Virtual Private Network (VPN) Extension for 517 IPv6 VPN", RFC 4659, DOI 10.17487/RFC4659, September 2006, 518 . 520 [RFC4684] Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk, 521 R., Patel, K., and J. Guichard, "Constrained Route 522 Distribution for Border Gateway Protocol/MultiProtocol 523 Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual 524 Private Networks (VPNs)", RFC 4684, DOI 10.17487/RFC4684, 525 November 2006, . 527 [RFC4798] De Clercq, J., Ooms, D., Prevost, S., and F. Le Faucheur, 528 "Connecting IPv6 Islands over IPv4 MPLS Using IPv6 529 Provider Edge Routers (6PE)", RFC 4798, 530 DOI 10.17487/RFC4798, February 2007, 531 . 533 [RFC4925] Li, X., Ed., Dawkins, S., Ed., Ward, D., Ed., and A. 534 Durand, Ed., "Softwire Problem Statement", RFC 4925, 535 DOI 10.17487/RFC4925, July 2007, 536 . 538 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 539 IANA Considerations Section in RFCs", RFC 5226, 540 DOI 10.17487/RFC5226, May 2008, 541 . 543 [RFC5549] Le Faucheur, F. and E. Rosen, "Advertising IPv4 Network 544 Layer Reachability Information with an IPv6 Next Hop", 545 RFC 5549, DOI 10.17487/RFC5549, May 2009, 546 . 548 [RFC5565] Wu, J., Cui, Y., Metz, C., and E. Rosen, "Softwire Mesh 549 Framework", RFC 5565, DOI 10.17487/RFC5565, June 2009, 550 . 552 [RFC6074] Rosen, E., Davie, B., Radoaca, V., and W. Luo, 553 "Provisioning, Auto-Discovery, and Signaling in Layer 2 554 Virtual Private Networks (L2VPNs)", RFC 6074, 555 DOI 10.17487/RFC6074, January 2011, 556 . 558 [RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/ 559 BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February 560 2012, . 562 [RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP 563 Encodings and Procedures for Multicast in MPLS/BGP IP 564 VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012, 565 . 567 Authors' Addresses 569 Stephane Litkowski 570 Cisco 572 Email: slitkows@cisco.com 574 Swadesh Agrawal 575 Cisco 577 Email: swaagrawa@cisco.com 579 Krishna Muddenahally Ananthamurthy 580 Cisco 582 Email: kriswamy@cisco.com 584 Keyur Patel 585 Arrcus 587 Email: keyur@arrcus.com