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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: August 13, 2020 Cisco 6 K. Patel 7 Arrcus 8 February 10, 2020 10 Advertising IPv4 Network Layer Reachability Information with an IPv6 11 Next Hop 12 draft-ietf-bess-rfc5549revision-02 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 August 13, 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 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 document does not specify the use of the Extended Next Hop 305 Encoding capability with any other combinations of . For example, the Next Hop Encoding capability 307 specified in this document is not intended to be used for NLRI AFI/ 308 SAFIs whose definition already allows use of both IPv4 and IPv6 next 309 hops (e.g., AFI/SAFI = <1/132> as defined in [RFC4684]). Similarly, 310 it is not intended that the Extended Next Hop Encoding capability be 311 used for NLRI AFI/SAFIs for which there is already solution for 312 advertising a next hop of a different address family (e.g., AFI/SAFI 313 = <2/1>, <2/2>, or <2/4> with IPv4 Next Hop as per [RFC4798] and AFI/ 314 SAFI = <2/128> with IPv4 Next Hop as per [RFC4659]). 316 It is expected that if new AFI/SAFIs are defined in the future, their 317 definition will have provisions (where appropriate) for both IPv4 and 318 IPv6 Next Hops from the onset, with determination based on Length of 319 Next Hop Address field. Thus, new AFI/SAFIs are not expected to make 320 use of the Extended Next Hop Encoding capability. 322 A BGP speaker MUST only advertise to a BGP peer the IPv4 or VPN-IPv4 323 NLRI with an IPv6 Next Hop if the BGP speaker has first ascertained 324 via BGP Capability Advertisement that the BGP peer supports the 325 Extended Next Hop Encoding capability for the relevant AFI/SAFI pair. 327 The Extended Next Hop Encoding capability provides information about 328 next hop encoding for a given AFI/SAFI, assuming that AFI/SAFI is 329 allowed. It does not influence whether that AFI/SAFI is indeed 330 allowed. Whether a AFI/SAFI can be used between the BGP peers is 331 purely determined through the Multiprotocol Extensions capability 332 defined in [RFC4760]. 334 The Extended Next Hop Encoding capability MAY be dynamically updated 335 through the use of the Dynamic Capability capability and associated 336 mechanisms defined in [I-D.ietf-idr-dynamic-cap]. 338 5. Operations 340 By default, if a particular BGP session is running over IPvx (where 341 IPvx is IPv4 or IPv6), and if the BGP speaker sending an update is 342 putting its own address in as the next hop, then the next hop address 343 SHOULD be specified as an IPvx address, using the encoding rules 344 specified in the AFI/SAFI definition of the NLRI being updated. This 345 default behavior may be overridden by policy. 347 When a next hop address needs to be passed along unchanged (e.g., as 348 a Route Reflector (RR) would do), its encoding MUST NOT be changed. 349 If a particular RR client cannot handle that encoding (as determined 350 by the BGP Capability Advertisement), then the NLRI in question 351 cannot be distributed to that client. For sound routing in certain 352 scenarios, this will require that all the RR clients be able to 353 handle whatever encodings any of them may generate. 355 6. Usage Examples 357 6.1. IPv4 over IPv6 Core 359 The extensions defined in this document may be used as discussed in 360 [RFC5565] for the interconnection of IPV4 islands over an IPv6 361 backbone. In this application, Address Family Border Routers (AFBRs; 362 as defined in [RFC4925]) advertise IPv4 NLRI in the MP_REACH_NLRI 363 along with an IPv6 Next Hop. 365 The MP_REACH_NLRI is encoded with: 367 o AFI = 1 369 o SAFI = 1 371 o Length of Next Hop Network Address = 16 (or 32) 373 o Network Address of Next Hop = IPv6 address of Next Hop 375 o NLRI = IPv4 routes 377 During BGP Capability Advertisement, the PE routers would include the 378 following fields in the Capabilities Optional Parameter: 380 o Capability Code set to "Extended Next Hop Encoding" 382 o Capability Value containing 385 6.2. IPv4 VPN unicast over IPv6 Core 387 The extensions defined in this document may be used for support of 388 IPV4 VPNs over an IPv6 backbone. In this application, PE routers 389 would advertise VPN-IPv4 NLRI in the MP_REACH_NLRI along with an IPv6 390 Next Hop. 392 The MP_REACH_NLRI is encoded with: 394 o AFI = 1 396 o SAFI = 128 398 o Length of Next Hop Network Address = 24 (or 48) 400 o Network Address of Next Hop = VPN-IPv6 address of Next Hop whose 401 RD is set to zero 403 o NLRI = IPv4-VPN routes 405 During BGP Capability Advertisement, the PE routers would include the 406 following fields in the Capabilities Optional Parameter: 408 o Capability Code set to "Extended Next Hop Encoding" 410 o Capability Value containing 413 6.3. IPv4 VPN multicast over IPv6 Core 415 The extensions defined in this document may be used for support of 416 IPV4 multicast VPNs over an IPv6 backbone. In this application, PE 417 routers would advertise VPN-IPv4 NLRI in the MP_REACH_NLRI along with 418 an IPv6 Next Hop. 420 The MP_REACH_NLRI is encoded with: 422 o AFI = 1 424 o SAFI = 129 426 o Length of Next Hop Network Address = 24 (or 48) 427 o Network Address of Next Hop = VPN-IPv6 address of Next Hop whose 428 RD is set to zero 430 o NLRI = IPv4-VPN routes 432 During BGP Capability Advertisement, the PE routers would include the 433 following fields in the Capabilities Optional Parameter: 435 o Capability Code set to "Extended Next Hop Encoding" 437 o Capability Value containing 440 7. IANA Considerations 442 This document defines, in Section 4, a new Capability Code to 443 indicate the Extended Next Hop Encoding capability in the [RFC5492] 444 Capabilities Optional Parameter. The value for this new Capability 445 Code is 5, which is in the range set aside for allocation using the 446 "IETF Review" policy defined in [RFC5226]. 448 8. Security Considerations 450 This document does not raise any additional security issues beyond 451 those of BGP-4 and the Multiprotocol extensions for BGP-4. The same 452 security mechanisms are applicable. 454 Although not expected to be the typical case, the IPv6 address used 455 as the BGP Next Hop Address could be an IPv4-mapped IPv6 address (as 456 defined in [RFC4291]). Configuration of the security mechanisms 457 potentially deployed by the network operator (such as security checks 458 on next hop address) need to keep this case in mind also. 460 9. Acknowledgments 462 The authors would like to thank Francois Le Faucheur and Eric Rosen 463 for the edition and their work on [RFC5549]. 465 The authors would like to thank Yakov Rekhter, Pranav Mehta, and John 466 Scudder for their contributions to the approach defined in [RFC5549]. 468 10. References 470 10.1. Normative References 472 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 473 Requirement Levels", BCP 14, RFC 2119, 474 DOI 10.17487/RFC2119, March 1997, 475 . 477 [RFC2545] Marques, P. and F. Dupont, "Use of BGP-4 Multiprotocol 478 Extensions for IPv6 Inter-Domain Routing", RFC 2545, 479 DOI 10.17487/RFC2545, March 1999, 480 . 482 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 483 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 484 2006, . 486 [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private 487 Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February 488 2006, . 490 [RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, 491 "Multiprotocol Extensions for BGP-4", RFC 4760, 492 DOI 10.17487/RFC4760, January 2007, 493 . 495 [RFC5492] Scudder, J. and R. Chandra, "Capabilities Advertisement 496 with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February 497 2009, . 499 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 500 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 501 May 2017, . 503 [RFC8277] Rosen, E., "Using BGP to Bind MPLS Labels to Address 504 Prefixes", RFC 8277, DOI 10.17487/RFC8277, October 2017, 505 . 507 10.2. Informative References 509 [I-D.ietf-idr-dynamic-cap] 510 Ramachandra, S. and E. Chen, "Dynamic Capability for BGP- 511 4", draft-ietf-idr-dynamic-cap-14 (work in progress), 512 December 2011. 514 [RFC4659] De Clercq, J., Ooms, D., Carugi, M., and F. Le Faucheur, 515 "BGP-MPLS IP Virtual Private Network (VPN) Extension for 516 IPv6 VPN", RFC 4659, DOI 10.17487/RFC4659, September 2006, 517 . 519 [RFC4684] Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk, 520 R., Patel, K., and J. Guichard, "Constrained Route 521 Distribution for Border Gateway Protocol/MultiProtocol 522 Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual 523 Private Networks (VPNs)", RFC 4684, DOI 10.17487/RFC4684, 524 November 2006, . 526 [RFC4798] De Clercq, J., Ooms, D., Prevost, S., and F. Le Faucheur, 527 "Connecting IPv6 Islands over IPv4 MPLS Using IPv6 528 Provider Edge Routers (6PE)", RFC 4798, 529 DOI 10.17487/RFC4798, February 2007, 530 . 532 [RFC4925] Li, X., Ed., Dawkins, S., Ed., Ward, D., Ed., and A. 533 Durand, Ed., "Softwire Problem Statement", RFC 4925, 534 DOI 10.17487/RFC4925, July 2007, 535 . 537 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 538 IANA Considerations Section in RFCs", RFC 5226, 539 DOI 10.17487/RFC5226, May 2008, 540 . 542 [RFC5549] Le Faucheur, F. and E. Rosen, "Advertising IPv4 Network 543 Layer Reachability Information with an IPv6 Next Hop", 544 RFC 5549, DOI 10.17487/RFC5549, May 2009, 545 . 547 [RFC5565] Wu, J., Cui, Y., Metz, C., and E. Rosen, "Softwire Mesh 548 Framework", RFC 5565, DOI 10.17487/RFC5565, June 2009, 549 . 551 [RFC6074] Rosen, E., Davie, B., Radoaca, V., and W. Luo, 552 "Provisioning, Auto-Discovery, and Signaling in Layer 2 553 Virtual Private Networks (L2VPNs)", RFC 6074, 554 DOI 10.17487/RFC6074, January 2011, 555 . 557 [RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/ 558 BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February 559 2012, . 561 [RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP 562 Encodings and Procedures for Multicast in MPLS/BGP IP 563 VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012, 564 . 566 Authors' Addresses 568 Stephane Litkowski 569 Cisco 571 Email: slitkows@cisco.com 573 Swadesh Agrawal 574 Cisco 576 Email: swaagraw@cisco.com 578 Krishna Muddenahally Ananthamurthy 579 Cisco 581 Email: kriswamy@cisco.com 583 Keyur Patel 584 Arrcus 586 Email: keyur@arrcus.com