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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 NETLMM WG S. Gundavelli 3 Internet-Draft K. Leung 4 Intended status: Standards Track Cisco Systems 5 Expires: September 6, 2007 V. Devarapalli 6 Azaire Networks 7 K. Chowdhury 8 Starent Networks 9 B. Patil 10 Nokia 11 March 05, 2007 13 Proxy Mobile IPv6 14 draft-sgundave-mip6-proxymip6-02.txt 16 Status of this Memo 18 By submitting this Internet-Draft, each author represents that any 19 applicable patent or other IPR claims of which he or she is aware 20 have been or will be disclosed, and any of which he or she becomes 21 aware will be disclosed, in accordance with Section 6 of BCP 79. 23 Internet-Drafts are working documents of the Internet Engineering 24 Task Force (IETF), its areas, and its working groups. Note that 25 other groups may also distribute working documents as Internet- 26 Drafts. 28 Internet-Drafts are draft documents valid for a maximum of six months 29 and may be updated, replaced, or obsoleted by other documents at any 30 time. It is inappropriate to use Internet-Drafts as reference 31 material or to cite them other than as "work in progress." 33 The list of current Internet-Drafts can be accessed at 34 http://www.ietf.org/ietf/1id-abstracts.txt. 36 The list of Internet-Draft Shadow Directories can be accessed at 37 http://www.ietf.org/shadow.html. 39 This Internet-Draft will expire on September 6, 2007. 41 Copyright Notice 43 Copyright (C) The IETF Trust (2007). 45 Abstract 47 Host based IPv6 mobility is specified in Mobile IPv6 base 48 specification [RFC3775]. In that model, the mobile node is 49 responsible for doing the signaling to its home agent to enable 50 session continuity as it moves between subnets. The design principle 51 in the case of host-based mobility relies on the mobile node being in 52 control of the mobility management. Network based mobility allows IP 53 session continuity for a mobile node without its involvement in 54 mobility management. This specification describes a protocol 55 solution for network based mobility management that relies on Mobile 56 IPv6 signaling and reuse of home agent functionality. A proxy 57 mobility agent in the network which manages the mobility for a mobile 58 node is the reason for referring to this protocol as Proxy Mobile 59 IPv6. 61 Table of Contents 63 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 64 2. Conventions used in this document . . . . . . . . . . . . . . 5 65 3. Proxy Mobile IPv6 Protocol Overview . . . . . . . . . . . . . 8 66 4. Proxy Mobile IPv6 Protocol Security . . . . . . . . . . . . . 11 67 4.1. Peer Authorization Database Entries . . . . . . . . . . . 11 68 4.2. Security Policy Database Entries . . . . . . . . . . . . . 12 69 5. Local Mobility Anchor Operation . . . . . . . . . . . . . . . 13 70 5.1. Extensions to Binding Cache Conceptual Data Structure . . 14 71 5.2. Bi-Directional Tunnel Management . . . . . . . . . . . . . 15 72 5.3. Routing Considerations . . . . . . . . . . . . . . . . . . 16 73 5.4. Local Mobility Anchor Address Discovery . . . . . . . . . 17 74 5.5. Sequence Number and Time-Stamps for Message Ordering . . . 18 75 5.6. IPv4 Home Address Mobility Support . . . . . . . . . . . . 19 76 5.7. IPv4 Transport Support . . . . . . . . . . . . . . . . . . 20 77 5.8. Route Optimizations Considerations . . . . . . . . . . . . 20 78 5.9. Mobile Prefix Discovery Considerations . . . . . . . . . . 20 79 5.10. Local Mobility Anchor Operational Summary . . . . . . . . 21 80 6. Mobile Access Gateway Operation . . . . . . . . . . . . . . . 23 81 6.1. Address Configuration Models . . . . . . . . . . . . . . . 23 82 6.2. Conceptual Data Structures . . . . . . . . . . . . . . . . 24 83 6.3. Access Authentication . . . . . . . . . . . . . . . . . . 25 84 6.4. Home Network Emulation . . . . . . . . . . . . . . . . . . 25 85 6.5. Link-Local and Global Address Uniqueness . . . . . . . . . 26 86 6.6. IPv4 Home Address Mobility Support . . . . . . . . . . . . 27 87 6.7. IPv4 Transport Support . . . . . . . . . . . . . . . . . . 27 88 6.8. Tunnel Management . . . . . . . . . . . . . . . . . . . . 28 89 6.9. Routing Considerations . . . . . . . . . . . . . . . . . . 29 90 6.10. Interaction with DHCP Relay Agent . . . . . . . . . . . . 30 91 6.11. Mobile Node Detachment Detection and Resource Cleanup . . 30 92 6.12. Coexistence with Mobile Nodes using Host-based Mobility . 31 93 6.13. Mobile Access Gateway Operation Summary . . . . . . . . . 32 94 7. Mobile Node Operation . . . . . . . . . . . . . . . . . . . . 34 95 7.1. Booting up in a Proxy Mobile IPv6 Domain . . . . . . . . . 35 96 7.2. Roaming in the Proxy Mobile IPv6 Network . . . . . . . . . 36 97 7.3. IPv6 Host Protocol Parameters . . . . . . . . . . . . . . 36 98 8. Message Formats . . . . . . . . . . . . . . . . . . . . . . . 38 99 8.1. Proxy Binding Update . . . . . . . . . . . . . . . . . . . 38 100 8.2. Proxy Binding Acknowledgment . . . . . . . . . . . . . . . 39 101 8.3. Home Network Prefix Option . . . . . . . . . . . . . . . . 39 102 8.4. Time Stamp Option . . . . . . . . . . . . . . . . . . . . 41 103 8.5. Status Codes . . . . . . . . . . . . . . . . . . . . . . . 41 104 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 42 105 10. Security Considerations . . . . . . . . . . . . . . . . . . . 42 106 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 44 107 12. Appendix-A: Proxy Mobile IPv6 Deployment Models . . . . . . . 44 108 12.1. Case-1# Avoiding Global Mobility at home (MIPv6-HoA == 109 MN-HoA) . . . . . . . . . . . . . . . . . . . . . . . . . 45 110 12.2. Case-2# Requiring Global Mobility at home (MIPv6-CoA 111 == MN-HoA) . . . . . . . . . . . . . . . . . . . . . . . . 46 112 13. Appendix-B: Proxy Mobile IPv6 interactions with AAA 113 Infrastructure . . . . . . . . . . . . . . . . . . . . . . . . 47 114 14. Appendix-C: Supporting Shared-Prefix Model using DHCPv6 . . . 47 115 15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 48 116 15.1. Normative References . . . . . . . . . . . . . . . . . . . 48 117 15.2. Informative References . . . . . . . . . . . . . . . . . . 49 118 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 50 119 Intellectual Property and Copyright Statements . . . . . . . . . . 52 121 1. Introduction 123 Mobile IPv6 [RFC-3775] is the enabler for IPv6 mobility. It requires 124 Mobile IPv6 client functionality in the IPv6 stack of a mobile node. 125 Signaling between the MN and HA enables the creation and maintenance 126 of a binding between the MNs home address and care-of-address. 127 Mobile IPv6 has been designed to be an integral part of the IPv6 128 stack in a host. However there exist IPv6 stacks today that do not 129 have Mobile IPv6 functionality and there would likely be IPv6 stacks 130 without MIPv6 functionality in the future as well. It is desirable 131 to support IP mobility for all hosts irrespective of the presence or 132 absence of mobile IPv6 functionality in the IPv6 stack. 134 It is possible to support mobility for IPv6 nodes by extending Mobile 135 IPv6 [RFC-3775] signaling and reusing the home agent via a proxy 136 mobility agent in the network. This approach to supporting mobility 137 does not require the mobile node to be involved in the signaling 138 required for mobility management. The proxy agent in the network 139 performs the signaling and does the mobility management on behalf of 140 the mobile node. Because of the use and extension of Mobile IPv6 141 signaling and home agent functionality, it is referred to as Proxy 142 Mobile IPv6 (PMIP6) in the context of this document. 144 Network deployments which are designed to support mobility would be 145 agnostic to the capability in the IPv6 stack of the nodes which it 146 serves. IP mobility for nodes which have mobile IP client 147 functionality in the IPv6 stack as well as those hosts which do not, 148 would be supported by enabling PMIP6 protocol functionality in the 149 network. The advantages of developing a network based mobility 150 protocol based on Mobile IPv6 are: 152 o Reuse of home agent functionality and the messages/format used in 153 mobility signaling. Mobile IPv6 is a mature protocol with several 154 implementations that have been through interoperability testing. 156 o A common home agent would serve as the mobility agent for all 157 types of IPv6 nodes. 159 o Addresses a real deployment need. 161 The problem statement and the need for a network based mobility 162 protocol solution has been documented in 163 [draft-ietf-netlmm-nohost-ps-05.txt]. PMIP6 is a solution that 164 addresses these issues and requirements. 166 The IP Mobility protocols designed in the IETF so far involve the 167 host in mobility management. There are some deployment scenarios 168 where a network-based mobility management protocol is considered 169 appropriate. The advantages to using a network-based mobility 170 protocol include avoiding tunneling overhead over the air and support 171 for hosts that do not implement any mobility management protocol. 173 The document describes a network-based mobility management protocol 174 based on Mobile IPv6. it is called Proxy Mobile IPv6 (PMIPv6). One 175 of the most important design considerations behind PMIPv6 has been to 176 re-use as much as possible from the existing mobility protocols. 178 There are many advantages to develop a protocol based on Mobile IPv6. 179 Mobile IPv6 is a very mature mobility protocol for IPv6. There have 180 been many implementations and inter-operability events where Mobile 181 IPv6 has been tested. There also numerous specifications enhancing 182 Mobile IPv6 that can be re-used. Further, the Proxy MIPv6 solution 183 described in this document allows the same Home Agent to provide 184 mobility to hosts that use Mobile IPv6 and hosts that do not use any 185 mobility management protocol. Proxy Mobile IPv6 provides solution to 186 a real deployment problem. 188 2. Conventions used in this document 190 The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 191 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" used in 192 this document are to be interpreted as described in RFC 2119. 194 All the general mobility related terms used in this document are to 195 be interpreted as defined in the Mobile IPv6 base specification [RFC- 196 3775]. 198 This document adopts the terms, Local Mobility Anchor (LMA) and 199 Mobile Access Gateway (MAG) from the NETLMM Goals document 200 [draft-ietf-netlmm-nohost-req-05.txt]. It further provides the 201 following context specific explanation to these terms, specific to 202 this solution document. 204 Local Mobility Anchor (LMA) 206 Local Mobility Anchor is the home agent for the mobile node in the 207 Proxy Mobile IPv6 domain. It is the topological anchor point for 208 the mobile node's home prefix and is the entity that manages the 209 mobile node's reachability state. It is important to understand 210 that the LMA has the functional capabilities of a home agent as 211 defined in Mobile IPv6 base specification [RFC-3775] and with the 212 additional required capabilities for supporting Proxy Mobile IPv6 213 as defined in this specification. 215 Mobile Access Gateway (MAG) 217 Mobile Access Gateway (MAG) is the proxy mobility agent in the 218 network which manages the mobility related signaling for a mobile 219 node that is attached to its access link. It is the entity 220 responsible for tracking the mobile node's attachment to the link 221 and for signaling the mobile node's local mobility anchor. 223 The following new terminology and abbreviations are introduced in 224 this document. 226 Mobile Node (MN) 228 Through out this document, the term mobile node is used to refer 229 to an IP node whose mobility is provided by the network. The 230 mobile node may be operating in IPv6 mode, IPv4 mode or in IPv4/ 231 IPv6 dual mode. The mobile node is not required to participate in 232 any mobility related signaling for achieving mobility for an IP 233 address that is obtained in that local domain. This document 234 further uses explicit text when referring to a mobile node that is 235 involved in mobility related signaling as per Mobile IPv6 236 specification [RFC-3775]. The mobile node's capability or its 237 involvement in any mobility related signaling for obtaining 238 mobility for an address that is obtained outside the current proxy 239 mobile IPv6 domain, is not relevant in the context of this 240 document and this definition of the Mobile Node shall survive. 242 Mobile Node's Home Address (MN-HoA) 244 MN-HoA is the home address of a mobile node in a Proxy Mobile IPv6 245 domain. It is an address obtained by the mobile node in that 246 domain. The mobile node can continue to use this address as long 247 as it is attached to the network that is in the scope of that 248 Proxy Mobile IPv6 domain. When supporting IPv4 address mobility 249 for a mobile node, the term, IPv4 MN-HoA is used to refer to the 250 IPv4 address of the mobile node. 252 Proxy Care-of Address (Proxy-CoA) 254 Proxy-CoA is the address configured on the interface of the mobile 255 access gateway and is the transport endpoint of the tunnel between 256 the local mobility anchor and the mobile access gateway. The 257 local mobility anchor views this address as the Care-of Address of 258 the mobile node and registers it in the Binding Cache entry for 259 that mobile node. When the transport network between the mobile 260 access gateway and the local mobility anchor is an IPv4 network 261 and if the care-of address that is registered at the local 262 mobility anchor is an IPv4 address, the term, IPv4 Proxy-CoA is 263 used. 265 LMA Address (LMAA) 267 The address that is configured on the interface of the local 268 mobility anchor and is the transport endpoint of the tunnel 269 between the local mobility anchor and the mobile access gateway. 270 This is the address to where the mobile access gateway sends the 271 Proxy Binding Update messages. When supporting IPv4 traversal, 272 i.e. when the network between the local mobility anchor and the 273 mobile access gateway is an IPv4 network, this address will be an 274 IPv4 address and will be referred to as IPv4 LMAA. 276 Proxy Mobile IPv6 Domain (PMIPv6-Domain) 278 It is a localized mobility management domain. It is a portion of 279 the access network where the mobility management of a mobile node 280 is handled using Proxy Mobile IPv6 protocol as defined in this 281 specification. 283 Mobile Node's Home Link 285 This is the link on which the mobile node obtained its initial 286 address configuration after it moved into that Proxy Mobile IPv6 287 domain. This is the link that conceptually follows the mobile 288 node. The network will ensure the mobile node always sees this 289 link with respect to the layer-3 network configuration, on any 290 access link that it attaches to in that proxy mobile IPv6 domain. 292 Mobile Node's Home Network Prefix (MN-HNP) 294 This is the on-link prefix that the mobile always sees in the 295 Proxy Mobile IPv6 domain. The home network prefix is 296 topologically anchored at the mobile's local mobility anchor. The 297 mobile node configures its interface with an address from this 298 prefix. When supporting IPv4 home address mobility, the term, 299 IPv4 Home Network refers to the mobile node's IPv4 home prefix and 300 the term, Home Network always refers to the IPv6 home network 301 prefix. 303 Mobile Node Identifier (MN-Identifier) 305 The identity of the mobile node that was presented to the network 306 as part of the access authentication. This is typically an 307 identifier such as Mobile Node NAI [RFC-4283] or in other format 308 specific to the access technology. 310 Proxy Binding Update (PBU) 312 A signaling message sent by the mobile access gateway to a mobile 313 node's local mobility anchor for establishing a binding between 314 the mobile node's MN-HoA and the Proxy-CoA. 316 Proxy Binding Acknowledgement (PBA) 318 A response message sent by a local mobility anchor in response to 319 a Proxy Binding Update message that it received from a mobile 320 access gateway. 322 3. Proxy Mobile IPv6 Protocol Overview 324 This specification describes a network-based mobility management 325 protocol. It is called Proxy Mobile IPv6 (PMIPv6) and is based on 326 Mobile IPv6 [RFC-3775]. This protocol is for providing network-based 327 mobility management support to a mobile node, within a restricted and 328 topologically localized portion of the network and with out requiring 329 the participation of the mobile node in any mobility related 330 signaling. 332 Every mobile node that roams in a Proxy Mobile IPv6 domain, would 333 typically be identified by an identifier, such as MN-Identifier, and 334 using that identifier the mobile node's policy profile can be 335 obtained from the policy store. The policy profile typically 336 contains the provisioned network-based mobility service 337 characterstics and other related parameters such as the mobile node's 338 home network prefix, permitted address configuration modes, roaming 339 policy and other parameters that are essential for providing network 340 based mobility service. 342 Once a mobile node enters its Proxy Mobile IPv6 domain and performs 343 access authentication, the network will ensure the mobile node is 344 always on its home network and further ensures the mobile node can 345 always obtain its home address on the access link and using any of 346 the address configuration procedures. In other words, there is home 347 network prefix that is assigned for a mobile node and conceptually 348 that address always follows the mobile node, where ever it roams 349 within that proxy mobile IPv6 domain. From the perspective of the 350 mobile node, the entire Proxy Mobile IPv6 domain appears as its home 351 link or a single link. 353 +----+ +----+ 354 |LMA1| |LMA2| 355 +----+ +----+ 356 LMAA1---- | | ---- LMAA2 357 | | 358 \\ // \\ 359 +--\\------------- //---\\----+ 360 ( \\ IPv4/IPv6 // \\ ) 361 ( \\ Network // \\ ) 362 +-----\\--------//---------\\-+ 363 \\ // \\ 364 \\ // \\ <--- Tunnel2 365 \\ // \\ 366 |-- Proxy-CoA1 |-- Proxy-CoA2 367 +----+ +----+ 368 [MN1].__.|MAG1|.__.[MN2] |MAG2| 369 +----+ +----+ 370 | | 371 | | 372 ------------------- [MN5] 373 | | 374 [MN3] [MN4] 376 Figure 1: Proxy Mobile IPv6 Domain 378 The Proxy Mobile IPv6 scheme introduces a new function, the mobile 379 access gateway. It is a function that is on the access link where 380 the mobile is anchored and does the mobility related signaling on 381 behalf of the mobile node. From the perspective of the local 382 mobility anchor, the mobile access gateway is a special element in 383 the network that is authorized to send Mobile IPv6 signaling messages 384 on behalf of a mobile node. 386 When the mobile node attaches to an access link connected to the 387 mobile access gateway, the mobile node presents its identity, MN- 388 Identifier, as part of the access access authentication procedure. 389 After a successful access authentication, the mobile access gateway 390 obtains the mobile node's profile from the policy store, such as from 391 a AAA infrastructure. The mobile access gatway would have all the 392 information for it to emulate the mobile node's home network on the 393 access link. The mobile access gateway also starts sending periodic 394 Router Advertisements to the mobile node advertising its home network 395 prefix. 397 The mobile node on receiving these Router Advertisement messages on 398 the access link will attempt to configure its interface either using 399 statefull or stateless address configuration modes, based on modes 400 that are permitted on that access link. At the end of a successful 401 address configuration procedure, the mobile node would have obtained 402 an address from its home network prefix. If the mobile node is IPv4 403 capable and if network offers IPv4 network mobility for the mobile 404 node, the mobile node would have obtained an IPv4 address as well. 405 The mobile node can be operating in IPv4-only mode, IPv6-only or in 406 dual-mode and based on the services enabled for that mobile, the 407 mobility is enabled only for those address types. Also, the network 408 between the local mobility anchor and the mobile access gateway can 409 be either IPv4, IPv6, IPv4 with NAT translation devices in the access 410 network. 412 For updating the local mobility anchor about the current location of 413 the mobile mode, the mobile access gateway sends a Proxy Binding 414 Update message to the mobile node's local mobility anchor. The 415 message will have the mobile node's NAI identifier option and Home 416 Network Prefix Option and/or IPv4 Home Address option. The source 417 address of that message will be the address of the mobile access 418 gateway on its egress interface. Upon accepting the Proxy Binding 419 Update request, the mobile access gateway sends a Proxy Binding 420 Acknowledgment message to the mobile access gateway. It also sets up 421 a route to the mobile node's home network prefix over the tunnel and 422 sends Proxy Binding Acknowledgment message to the mobile access 423 gateway. 425 The mobile access gateway on receiving this Proxy Binding 426 Acknowledgment message sets up a tunnel to the local mobility anchor 427 and adds a default route over the tunnel to the local mobility 428 anchor. All traffic from the mobile node gets routed to the mobile 429 node's local mobility anchor over the tunnel. 431 At this point, the mobile node has a valid home address from its home 432 network prefix, at the current point of attachment. The serving 433 mobile access gateway and the local mobility anchor also have proper 434 routing states for handling the traffic sent to and from the mobile 435 node. 437 The local mobility anchor, being the topological anchor point for the 438 mobile node's home network prefix, it receives any packet sent by any 439 corresponding node to the mobile node. Local mobility anchor 440 forwards the received packet to the mobile access gateway through the 441 tunnel. The mobile access gateway on other end of the tunnel, after 442 receiving the packet removes the tunnel header and forwards the 443 packet on the access link to the mobile node. 445 The mobile access gateway typically acts as a default router on the 446 access link and any packet that the mobile node sends to any 447 corresponding node is received by the mobile access gateway and it 448 forwards the packet to the local mobility anchor through the tunnel. 449 The local mobility anchor on the other end of the tunnel, after 450 receiving the packet removes the tunnel header and routes the packet 451 to the destination. 453 4. Proxy Mobile IPv6 Protocol Security 455 The signaling messages, Proxy Binding Update and Proxy Binding 456 Acknowledgement, exchanged between the mobile access gateway and the 457 local mobility anchor are protected using IPsec and using the 458 established security association between them. The security 459 association of the specific mobile node for which the signaling 460 message is initiated is not required for protecting these messages. 462 ESP in transport mode with mandatory integrity protection is used for 463 protecting the signaling messages. Confidentiality protection is not 464 required. 466 IKEv2 is used to setup security associations between the mobile 467 access gateway and the local mobility anchor to protect the Proxy 468 Binding Update and Proxy Binding Acknowledgment messages. The mobile 469 access gateway and the local mobility anchor can use any of the 470 authentication mechanisms, as specified in IKEv2, for mutual 471 authentication. 473 Mobile IPv6 specification requires the home agent to prevent a mobile 474 node from creating security associations or creating binding cache 475 entries for another mobile node's home address. In the protocol 476 described in this document, the mobile node is not involved in 477 creating security associations for protecting the signaling messages 478 or sending binding updates. Therefore, this is not a concern. 479 However, the local mobility anchor MUST allow only authorized mobile 480 access gateways to create binding cache entries on behalf of the 481 mobile nodes. The actual mechanism by which the local mobility 482 anchor verifies if a specific mobile access gateway is authorized to 483 send Proxy Binding Updates on behalf of a mobile node is outside the 484 scope of this document. One possible way this could be achieved is 485 sending a query to the policy store such as by using AAA 486 infrastrucure. 488 4.1. Peer Authorization Database Entries 490 The following describes PAD entries on the mobile access gateway and 491 the local mobility anchor. The PAD entries are only example 492 configurations. Note that the PAD is a logical concept and a 493 particular mobile access gateway or a local mobility anchor 494 implementation can implement the PAD in an implementation specific 495 manner. The PAD state may also be distributed across various 496 databases in a specific implementation. 498 mobile access gateway PAD: 499 - IF remote_identity = lma_identity_1 500 Then authenticate (shared secret/certificate/EAP) 501 and authorize CHILD_SA for remote address lma_addres_1 503 local mobility anchor PAD: 504 - IF remote_identity = mag_identity_1 505 Then authenticate (shared secret/certificate/EAP) 506 and authorize CHILD_SAs for remote address mag_address_1 508 The list of authentication mechanisms in the above examples is not 509 exhaustive. There could be other credentials used for authentication 510 stored in the PAD. 512 4.2. Security Policy Database Entries 514 The following describes the security policy entries on the mobile 515 access gateway and the local mobility anchor required to protect the 516 Proxy Mobile IPv6 signaling messages. The SPD entries are only 517 example configurations. A particular mobile access gateway or a 518 local mobility anchor implementation could configure different SPD 519 entries as long as they provide the required security. 521 In the examples shown below, the identity of the mobile access 522 gateway is assumed to be mag_1, the address of the mobile access 523 gateway is assumed to be mag_address_1, and the address of the local 524 mobility anchor is assumed to be lma_address_1. 526 mobile access gateway SPD-S: 527 - IF local_address = mag_address_1 & 528 remote_address = lma_address_1 & 529 proto = MH & local_mh_type = BU & remote_mh_type = BAck 530 Then use SA ESP transport mode 531 Initiate using IDi = mag_1 to address lma_1 533 local mobility anchor SPD-S: 534 - IF local_address = lma_address_1 & 535 remote_address = mag_address_1 & 536 proto = MH & local_mh_type = BAck & remote_mh_type = BU 538 Then use SA ESP transport mode 540 5. Local Mobility Anchor Operation 542 For supporting the Proxy Mobile IPv6 scheme defined in this document, 543 the Mobile IPv6 home agent entity, defined in Mobile IPv6 544 specification [RFC-3775], needs some protocol enhancements. The 545 local mobility anchor is the functional entity with these 546 capabilities for supporting Proxy Mobile IPv6. This section 547 describes the operational details of the local mobility anchor. 549 The base Mobile IPv6 specification [RFC-3775], defines home agent and 550 the mobile node as the two functional entities. The Proxy Mobile 551 IPv6 scheme introduces a new entity, the mobile access gateway. This 552 is the entity that will participate in the mobility related 553 signaling. From the perspective of the local mobility anchor, the 554 mobile access gateway is a special element in the network that has 555 the privileges to send mobility related signaling messages on behalf 556 of the mobile node. Typically, the local mobility anchor is 557 provisioned with the list of mobile access gateways authorized to 558 send proxy registrations. 560 When the local mobility anchor receives a Proxy Binding Update 561 message from a mobile access gateway, the message is protected using 562 the IPSec Security Association established between the local mobility 563 anchor and the mobile access gateway. The local mobility anchor can 564 distinguish between a Proxy Binding Update message received from a 565 mobile access gateway from a Binding Update message received directly 566 from a mobile node. This distinction is important for using the 567 right security association for validating the Binding Update and this 568 is achieved by relaxing the MUST requirement for having the Home 569 Address Option presence in Destination Options header and by 570 introducing a new flag in the Binding Update message. The local 571 mobility anchor as a traditional IPSec peer can use the SPI in the 572 IPSec header [RFC-4306] of the received packet for locating the 573 correct security association and for processing the Proxy Binding 574 Update message in the context of the Proxy Mobile IPv6 scheme. 576 For protocol simplicity, the current specification supports the Per- 577 MN-Prefix addressing model. In this addressing model, each mobile 578 node is allocated an exclusively unique home network prefix and the 579 prefix is not hosted on the home link. The local mobility anchor in 580 this addressing model is just a topological anchor point and the 581 prefix is physically hosted on the access link where the mobile node 582 is attached. The local mobility anchor is not required to perform 583 any proxy ND operations [RFC-2461] for defending the mobile node's 584 home address, MN-HoA, on the home link. However, the local mobility 585 anchor is required to manage the binding cache entry of the mobile 586 node for managing the mobility session and also the routing state for 587 creating a proper route path for traffic to/from the mobile node. 589 5.1. Extensions to Binding Cache Conceptual Data Structure 591 The local mobility anchor maintains a Binding Cache entry for each 592 currently registered mobile node. Binding Cache is a conceptual data 593 structure, described in Section 9.1 of [RFC3775]. For supporting 594 this specification, the conceptual Binding Cache entry needs to be 595 extended with the following new fields. 597 o A flag indicating whether or not this Binding Cache entry is 598 created due to a proxy registration. This flag is enabled for 599 Binding Cache entries that are proxy registrations and is turned 600 off for all other entries that are direct registrations from the 601 mobile node. 603 o A flag indicating if IPv4 HoA mobility binding is accepted. If 604 this flag is set, the relevant IPv4 fields in this data structure 605 have to be set to the configured values. 607 o A flag indicating if IPv6 HoA mobility is accepted. If this flag 608 is set, the relevant IPv4 HoA fields in this data structure have 609 to be set to the configured values. If this flag. 611 o The identifier of the mobile node, MN-Identifier. This MN- 612 Identifier is obtained from the NAI Option present in the Proxy 613 Binding Update request [RFC-4285]. 615 o A flag indicating whether or not the Binding Cache entry has a 616 home address that is on virtual interface. This flag is enabled, 617 if the home prefix of the mobile is configured on a virtual 618 interface. When the configured home prefix of a mobile is on a 619 virtual interface, the home agent is not required to function as a 620 Neighbor Discovery proxy for the mobile node. 622 o The IPv6 home network prefix of the mobile node. 624 o The IPv6 home network prefix length of the mobile node. 626 o The IPv4 home address of the mobile node, if IPv4 home address 627 mobility is enabled and if the mobile has obtained an address. 629 o The IPv4 home network prefix length of the mobile node, if IPv4 630 home address mobility is enabled. 632 o The IPv4 default-router address of the mobile node, if IPv4 home 633 address mobility is enabled. This is the IPv4 LMAA. 635 o The interface id of the tunnel between the local mobility anchor 636 and the mobile access gateway used for sending and receiving the 637 mobile node's traffic. 639 o Tentative binding cache entry with all the above fields. This 640 entry is populated upon tentatively accepting a proxy binding 641 update request for a mobile node whose direct registration still 642 exists, i.e. the mobile has not deregistered and it received a 643 proxy binding update request. 645 5.2. Bi-Directional Tunnel Management 647 The bi-directional tunnel between the local mobility anchor and the 648 mobile access gateway is used for routing the traffic to and from the 649 mobile node. The tunnel hides the topology and enables a mobile node 650 to use an IP address that is topologically anchored at the local 651 mobility anchor, from any attached access link in that proxy mobile 652 IPv6 domain. The base Mobile IPv6 specification [RFC-3775], does use 653 the tunneling scheme for routing traffic to and from the mobile that 654 is using its home address. However, there are subtle differences in 655 the way Proxy Mobile IPv6 uses the tunneling scheme. 657 As in Mobile IPv4 [RFC-3344], the tunnel between the local mobility 658 anchor and the mobile access gateway is typically a shared tunnel and 659 can be used for routing traffic streams for different mobile nodes 660 attached to the same mobile access gateway. This specification 661 extends that 1:1 relation between a tunnel and a binding cache entry 662 to 1:m relation, reflecting the shared nature of the tunnel. 664 The tunnel is creating after accepting a Proxy Binding Update request 665 for a mobile node from a mobile access gateway. The created tunnel 666 may be shared with other mobile nodes attached to the same mobile 667 access gateway and with the local mobility anchor having a binding 668 cache entry for those mobile nodes. Some implementations may prefer 669 to use static tunnels as supposed to creating and tearing them down 670 on a need basis. 672 The one end point of the tunnel is the address configured on the 673 interface of the local mobility anchor, LMAA or IPv4 LMAA. The other 674 end point of the tunnel is the address configured on the interface of 675 the mobile access gateway, Proxy-CoA or IPv4 Proxy-CoA. The tunnel 676 encapsulation mode can be either IPv6/IPv6, IPv6/IPv4, IPv6/IPv4-UDP, 677 IPv4/IPv6, IPv4/IPv4-UDP, based on the transport mode and the 678 presence of NAT translation devices on the path. 680 Implementations typically use a software timer for managing the 681 tunnel lifetime and a counter for keeping a count of all the mobiles 682 that are sharing the tunnel. The timer value will be set to the 683 accepted binding life-time and will be updated after each periodic 684 registrations for extending the lifetime. If the tunnel is shared 685 for multiple mobile node's traffic, the tunnel lifetime will be set 686 to the highest binding life time across all the binding life time 687 that is granted for all the mobiles sharing that tunnel. 689 5.3. Routing Considerations 691 This section describes how the data traffic to/from the mobile node 692 is handled at the local mobility anchor. The following entries 693 explains the routing state that is created for the mobile node home 694 network prefix. 696 IPv6 traffic for the Mobile Node's home address: 697 ================================================ 698 MN-HoA::/64 via tunnel0, next-hop Proxy-CoA 700 IPv4 traffic for the Mobile Node's Home Address: 701 ================================================ 702 IPv4-MN-HoA/32 via tunnel0, next-hop IPv4-Proxy-CoA 704 tunnel0: 705 ======== 706 Source: LMAA or IPv4 LMAA 707 Destination: Proxy-CoA or IPv4 Proxy-CoA 708 Tunnel Transport: IPv6 or IPv4 709 Tunnel Payload: IPv6, IPv4 or IPv4-UDP 711 The local mobility anchor functions as a topological anchor point for 712 the mobile node's home network prefix. When the local mobility 713 anchor receives a data packet from a corresponding node, destined for 714 the mobile node's home network prefix, the created routing state will 715 enable the packets to be forwarded to the mobile node through the bi- 716 directional tunnel established between itself and the serving mobile 717 access gateway. 719 If the tunnel between the local mobility anchor and the mobile access 720 gateway is an IPv6 tunnel, i.e. if the registered care-of address is 721 the IPv6 Proxy-CoA, any IPv6 packets received from any corresponding 722 node for the mobile node's home network prefix, MN-HNP, will be 723 encapsulated in an IPv6 packet, IPv6/IPv6 mode, and will be carried 724 as an IPv6 packet. And any IPv4 packets for the mobile node's IPv4- 725 MN-HoA, will be encapsulated in an IPv6 packet, IPv4/IPv6 mode, and 726 will be carried as an IPv6 packet. 728 If the tunnel between the local mobility anchor and the mobile access 729 gateway is an IPv4 tunnel, i.e. if the registered care-of address is 730 the IPv4 Proxy-CoA, any IPv6 packets received from any corresponding 731 node for the mobile node's home network prefix, MN-HNP, will be 732 encapsulated in an UDP header of an IPv4 packet, IPv6/IPv4-UDP mode, 733 and will be carried as an IPv4 packet. And any IPv4 packet from any 734 corresponding node, will be encapsulated in an UDP header of an IPv4 735 packet, IPv4/IPv4-UDP mode, and will be carried as an IPv4 packet. 736 In both these cases, the UDP header will not be there, if there is no 737 presence of NAT devices detected on the path. 739 All the reverse tunneled packets that the local mobility anchor 740 receives from the tunnel, after removing the packet encapsulation 741 will get routed to the destination specified in the inner packet 742 header. These routed packets will have the source address field set 743 to the mobile node's home address. 745 5.4. Local Mobility Anchor Address Discovery 747 Dynamic Home Agent Address Discovery, as explained in Section 10.5 of 748 [RFC-3775], allows a mobile node to discover all the home agents on 749 its home link by sending an ICMP Home Agent Address Discovery Request 750 message to the Mobile IPv6 Home-Agents anycast address, derived from 751 its home network prefix. 753 The Proxy Mobile IPv6 model assumes that the mobile access gateway 754 will be able to obtain the address of the local mobility anchor in 755 one or more ways. This MAY be a configured entry in the mobile 756 node's policy profile, or it MAY be obtained through mechanisms 757 outside the scope of this document. It is important to note that 758 there is little value in using DHAAD for discovering the local 759 mobility anchor address dynamically. As a mobile moves from one 760 mobile access gateway to the another, the serving mobile access 761 gateway will not predictably be able to locate the serving local 762 mobility anchor for that mobile that has its binding cache entry for 763 the mobile node. However, if there is only one local mobility anchor 764 configured to serve a mobile node, the mobile access gateway can use 765 Dynamic Home Agent Address Discovery scheme for discovering the 766 address of the local mobility anchor. 768 With the currently supported Per-MN-Prefix addressing model, every 769 mobile node is assigned a unique home network prefix, the local 770 mobility anchor is a topological anchor point for that prefix and 771 with the prefix being hosted on the access link attached to the 772 mobile access gateway. For the discovery scheme to work, the local 773 mobility anchor MUST be able to receive the ICMP discovery packets 774 sent to the anycast address derived from the mobile node's home 775 network prefix. 777 5.5. Sequence Number and Time-Stamps for Message Ordering 779 Mobile IPv6 [RFC-3775] uses the Sequence Number field in registration 780 messages as a way to ensure the correct packet ordering. The local 781 mobility anchor and the mobile node are required to manage this 782 counter over the lifetime of a binding. 784 In Proxy Mobile IPv6, the Proxy Binding Update messages that the 785 local mobility anchor receives on behalf of a specific mobile node 786 may not be from the same mobile access gateway as the previously 787 received message. It creates certain ambiguity and the local 788 mobility anchor will not be predictably order the messages. This 789 could lead to the local mobility anchor processing an older message 790 from a mobile access gateway where the mobile node was previously 791 attached, while ignoring the latest binding update message. 793 In the Proxy Mobile IPv6, the ordering of packets has to be 794 established accross packets received from multiple senders. The 795 sequence number scheme as specified in [RFC-3775] will not be 796 sufficient. A global scale, such as a time stamp, can be used to 797 ensure the correct ordering of the packets. This document proposes 798 the use of a Time Stamp Option, specified in Section 8.4, in all 799 Proxy Binding Update messages sent by mobile access gateways. By 800 leveraging the NTP [RFC-1305] service, all the entities in Proxy 801 Mobile IPv6 domain will be able to synchronize their respective 802 clocks. Having a time stamp option in Proxy Binding Update messages 803 will enable the local mobility anchor to predictably identify the 804 latest message from a list of messages delivered in an out-of-order 805 fashion. 807 The Proxy Mobile IP model, defined in this document requires the 808 Binding Update messages sent by the mobile access gateway to have the 809 time stamp option. The local mobility anchor processing a proxy 810 registration MUST ignore the sequence number field and SHOULD use the 811 value from the Time Stamp option to establish ordering of the 812 received Binding Update messages. If the local mobility anchor 813 receives a Binding Update message with an invalid Time Stamp Option, 814 the Binding Update MUST be rejected and a Binding Acknowledgement 815 MUST be returned in which the Status field is set to 148 (invalid 816 time stamp option). 818 In the absence of Time Stamp option in the Proxy Binding Update, the 819 entities can fall back to Sequence Number scheme for message 820 ordering, as defined in RFC-3775. However, the specifics on how 821 different mobile access gateways synchronize the sequence number is 822 outside the scope of this document. 824 When using the Time Stamp Option, the local mobility anchor or the 825 mobile access gateway MUST set the the timestamp field to a 64-bit 826 value formatted as specified by the Network Time Protocol [RFC-1305]. 827 The low-order 32 bits of the NTP format represent fractional seconds, 828 and those bits which are not available from a time source SHOULD be 829 generated from a good source of randomness. 831 5.6. IPv4 Home Address Mobility Support 833 The transition from IPv4 to IPv6 is a long process and during this 834 period of transition, both the protocols will be enabled over the 835 same infrastructure. It is reasonable to assume that the mobile node 836 and the local mobility anchor are IPv4 and IPv6 enabled and further 837 it is also reasonable to expect the same mobility infrastructure to 838 provide IPv4 and IPv6 address mobility. The Proxy Mobile IPv6 scheme 839 defined in this document allows the mobile node to obtain an IPv4 840 address and to roam in the network using the same address. 842 When a mobile node attached to a mobile access gateway sends a DHCP 843 request, the network will ensure it gets an IP address from its home 844 address prefix. The mobile access on the access link where mobile 845 node is attached, will register this address with the local mobility 846 anchor using the IPv4 Home Address option, defined in Section 3.1.1, 847 DSMIP6 draft [draft-ietf-mip6-nemo-v4traversal-03.txt]. Upon 848 receiving the Proxy Binding Update Message with this IPv4 Home 849 Address option, the local mobility anchor is required to apply the 850 processing rules as specified in DSMIP6 draft. Further, if the 851 received option has a value set to 0.0.0.0, the local mobility anchor 852 needs to consider this as a request for an IPv4 Home Address 853 allocation and must return the allocated value in the IPv4 Home 854 Address option carried in the Proxy Binding Acknowledgement. 856 Upon accepting the registration for the mobile node's IPv4 home 857 address, the local mobility anchor will add an IPv4 host route over 858 the tunnel to the mobile access gateway. Any IPv4 packets that the 859 local mobility anchor receives from a correspondent node will be 860 tunneled to the mobile access gateway over the IPv4/IPv6 tunnel, and 861 then routed accordingly after removing the tunnel header. 863 5.7. IPv4 Transport Support 865 It is possible the transport network between the local mobility 866 anchor and the mobile access gateway is an IPv4 network. Further, it 867 is possible the access network is behind a NAT translation device 868 with the mobile access gateway using an IPv4 private address. 870 For supporting the mobile node's mobility of the MN-HoA and IPv4 MN- 871 HoA, the IPv4 tunnel established between the local mobility anchor 872 and the mobile access gateway will be used routing the mobile node's 873 IPv4 and IPv6 traffic. 875 The DSMIP6 specification provides the semantics on how the IPv4 876 tunnel needs to be negotiated and the detection logic of the NAT 877 devices. This specification leverages the DSMIP6 work and extends 878 the use of the NAT Detection Option defined for Binding 879 Acknowledgement to Proxy Binding Acknowledgement messages. 881 5.8. Route Optimizations Considerations 883 Mobile IPv6 route optimization, as defined in [RFC-3775], enables a 884 mobile node to communicate with a corresponding node directly using 885 its care-of address and further the Return Routability procedure 886 enables the corresponding node to have reasonable trust that the 887 mobile node owns both the home address and care-of address. 889 In the Proxy Mobile IPv6 model, the mobile is not involved in any 890 mobility related signaling and also it does not operate in the dual- 891 address mode. Hence, the return routability procedure as defined in 892 RFC-3775 is not applicable for the proxy model. This document does 893 not address the Route Optimization problem and leaves this work item 894 for future enhancements. 896 5.9. Mobile Prefix Discovery Considerations 898 The ICMP Mobile Prefix Advertisement message, described in Section 899 6.8 and Section 11.4.3 of [RFC-3775], allows a home agent to send a 900 Mobile Prefix Advertisement to the mobile node. 902 In Proxy Mobile IPv6 deployments, the mobile node's home network 903 prefix is hosted on the access link shared between the mobile access 904 gateway and the mobile node, but topologically anchored on the local 905 mobility anchor. Since, there is no physical home-link for the 906 mobile node's home network prefix on the local mobility anchor and as 907 the mobile is always on the link where the prefix is hosted, any 908 prefix change messages can just be advertised by the mobile access 909 gateway on the access link and thus there is no applicability of this 910 messaging for Proxy Mobile IPv6. This specification does not support 911 Mobile Prefix Discovery. 913 5.10. Local Mobility Anchor Operational Summary 915 o For supporting this scheme, the local mobility anchor MUST satisfy 916 all the requirements listed in Section 8.4 of Mobile IPv6 917 specification [RFC-3775] with the following considerations. 919 o For supporting the per-MN-Prefix addressing model as defined in 920 this specification, the local mobility anchor service MUST NOT be 921 tied to a specific interface. It SHOULD be able to accept Proxy 922 Binding Update requests sent to any of the addresses configured on 923 any of its interfaces. 925 o The requirement for a home agent to maintain a list of home agents 926 for a mobile node's home link is not applicable for the local 927 mobility anchor, when supporting Per-MN-Prefix addressing model as 928 there is no link specific relation between the two. 930 o After receiving a Proxy Binding Update request from a mobile 931 access gateway on behalf of mobile node, the local mobility anchor 932 MUST process the request as defined in Section 10, of the base 933 Mobile IPv6 specification [RFC-3775], with one exception that this 934 request is a proxy request, the sender is not the mobile node and 935 so the message has to be processed with the considerations 936 explained in this section. 938 o The local mobility anchor MUST apply the required policy checks, 939 as explained in Section 4.0 of this document to verify the sender 940 is a a trusted mobile access gateway, authorized to send proxy 941 binding updates requests on behalf of that mobile nodes, using its 942 own identity. The local mobility anchor must check the local/ 943 remote policy store to ensure the requesting node is authorized to 944 send proxy binding update requests. 946 o Upon accepting a proxy binding update request from a mobile access 947 gateway, the local mobility anchor must check if there exists a 948 binding cache entry for that mobile node, identified using the MN- 949 Identifier, that was created due to a direct registration from the 950 mobile node. If there exists a binding cache entry with the proxy 951 registration flag turned off, the local mobility anchor MUST NOT 952 modify that binding state, instead it must create a tentative 953 binding cache entry and update the tentative binding cache entry 954 fields of that binding cache entry. 956 o Upon receiving a Binding Update request from a mobile node with 957 lifetime value set to 0, from a tunnel between itself and a 958 trusted mobile access gateway, the local mobility anchor upon 959 accepting that de-registration message, MUST forward the Binding 960 Acknowledgement message in the tunnel from where it received the 961 Binding Update request. It must also replace the binding cache 962 entry with the tentative binding cache entry and enable routing 963 for the mobile node's home prefix through the proxy mobile IPv6 964 tunnel. 966 o The local mobility anchor MUST use the MN-Identifier present in 967 the NAI option of the Proxy Binding Update request for identifying 968 the mobile node. 970 o The local mobility anchor MUST ensure the prefix presented in the 971 Home Network Prefix option of the received Proxy Binding Update 972 request is owned by itself and further the mobile node identified 973 by MN-Identifier is authorized to use this prefix. 975 o The local mobility anchor MUST ignore the sequence number field in 976 the Proxy Binding Updates requests, if the Time-Stamp Option is 977 present in the message. It must also skip all the checks related 978 to sequence number as suggested in the Mobile IPv6 specification 979 [RFC-3775]. However, the received sequence number MUST be copied 980 and returned in the Proxy Binding Acknowledgement sent to the 981 mobile access gateway. 983 o Upon accepting this request, the local mobility anchor must create 984 a Binding Cache entry with the home address from the Home Network 985 Prefix Option in the Binding Update and must set up a tunnel to 986 the proxy mobile agent serving the mobile node. This bi- 987 directional tunnel between the local mobility anchor and the 988 mobile access gateway is used for routing the mobile traffic. 990 o The local mobility anchors SHOULD drop all HoTI messages received 991 for a home address that has corresponding Binding Cache entry with 992 the proxy registration flag set. 994 o The local mobility anchor must handle the mobile node's data 995 traffic as explained in the Routing Considerations section of this 996 document. 998 6. Mobile Access Gateway Operation 1000 The Proxy Mobile IPv6 scheme specified in this document, introduces a 1001 new functional entity, the Mobile Access Gateway (MAG). It is the 1002 entity that detects the mobile node's movements and initiates the 1003 signaling with the mobile node's local mobility anchor for updating 1004 the route to the mobile node's home address. In essence, the mobile 1005 access gateway does the mobility management of the mobile node. 1007 From the perspective of the local mobility anchor, the mobile access 1008 gateway is a special element in the network that sends Mobile IPv6 1009 signaling messages on behalf of a mobile node, but using its own 1010 identity. It is the entity that binds the mobile node's home address 1011 to an address on its own access interface. 1013 The mobile access gateway has the following functional roles. 1015 o It is responsible for detecting the mobile node's attachment or 1016 detachment on the connected access link and for initiating the 1017 mobility signaling to the mobile node's local mobility anchor. 1019 o Emulation of the mobile node's home link on the access link. 1021 o It is responsible for setting up the data path for enabling the 1022 mobile node to use its home address for communication from the 1023 access link. 1025 This Proxy Mobile IPv6 scheme is independent of the underlying access 1026 technology or the link model. The interface between the mobile node 1027 and the mobile access gateway can be either: 1029 o Point-to-Point Link 1031 o Shared Link 1033 This specification does not support split links. 1035 6.1. Address Configuration Models 1037 Currently, this specification only supports Per-MN-Prefix model In 1038 the Per-MN-Prefix model, there is a unique home network prefix 1039 assigned for each mobile node and that prefix is hosted on the access 1040 link. Conceptually, the prefix just follows the mobile node as it 1041 moves within the proxy mobile IPv6 domain. In this addressing model, 1042 based on the administrative policy, the mobile node can use either 1043 Stateless Address Autoconfiguration or Statefull Address 1044 Configuration using DHCP for obtaining the IPv6 address configuration 1045 for its interface on the access link. Further, the mobile node can 1046 also generate interface identifiers with privacy considerations, as 1047 specified in Privacy Extensions specification [RFC-3041] and as per 1048 CGA specification [RFC-3042]. For IPv4 home address configuration, 1049 the mobile node can obtain the address configuration using DHCP or 1050 optionally by using IPCP. In addition to this, Other address 1051 configuration mechanisms specific to the access link between the 1052 mobile node and the mobile access gateway may also be used by the 1053 mobile node. 1055 The configured administrative policy for the mobile dictates the type 1056 of addressing model that is supported for a mobile on the access 1057 link. The mobile access gateway on the access router will control 1058 this by setting the relevant flags in the Router Advertisement that 1059 it sends on the access link. 1061 6.2. Conceptual Data Structures 1063 Every mobile access gateway maintains a Binding Update List for each 1064 currently attached mobile node. The Binding Update List is a 1065 conceptual data structure, described in Section 11.1 of Mobile IPv6 1066 base specification [RFC-3775]. For supporting this specification, 1067 the conceptual Binding Update List data structure must be extended 1068 with the following new additional fields. 1070 o The Identifier of the mobile node, MN-Identifier. The format of 1071 the MN-Identifier is specific to the access technology. This MN 1072 identifier is obtained as part of the Access Authentication 1073 procedure and is used for downloading the mobile node's profile 1074 from the policy store. 1076 o The physical address or the MAC address of the mobile node's 1077 connected interface. 1079 o The IPv6 home network prefix of the mobile node. 1081 o The IPv6 home network prefix length of the mobile node. 1083 o The link-local address of the mobile node on the link. This 1084 address MAY be learnt from the source address of the Router 1085 Solicitation message received from the mobile node. 1087 o The IPv4 home address of the mobile node, if IPv4 home address 1088 mobility is supported. 1090 o The IPv4 home network prefix length of the mobile node, if IPv4 1091 home address mobility is supported. 1093 o The IPv4 default-router address of the mobile node, if IPv4 home 1094 address mobility is supported. This is the IPv4 LMAA. 1096 o The tunnel identifier of the tunnel between the mobile access 1097 gateway and the local mobility anchor used for reverse tunneling 1098 the mobile node's traffic. On a given implementation, if a tunnel 1099 appears like a virtual interface, that applies the proper 1100 encapsulation on every packet that is routed through that 1101 interface, then the interface identifier is stored in the binding 1102 update list. entry. 1104 6.3. Access Authentication 1106 When a mobile node attaches to the access link connected to the 1107 mobile access gateway, the deployed access security protocols will 1108 ensure that only authorized mobile nodes will be able to access the 1109 link and further the mobile access gateway will be able to identify 1110 the mobile node by its MN-Identifier and optionally will be able to 1111 detect the mobile node's attachment or detachment to the link. The 1112 exact specifics on how this is achieved is outside the scope of this 1113 document. This document goes with the stated assumption of having an 1114 established trust between the mobile node and mobile access gateway 1115 on the access link before the protocol operation begins. The mobile 1116 access gateway will be able to use the mobile node's MN-Identity and 1117 will be obtain its policy profile from the network policy store or 1118 from the local policy store. 1120 6.4. Home Network Emulation 1122 One of the key functions of the mobile access gateway is to emulate 1123 the mobile node's home network on the access link. It has to ensure, 1124 the mobile node believes it is connected to its home link or the link 1125 where it obtained its address configuration after it moved into that 1126 proxy mobile IPv6 domain. After the access authentication is 1127 complete, the mobile access gateway will have access to the mobile 1128 node's profile, obtained from querying a local/network policy store 1129 or provided to it as part of some context transfer procedure. After 1130 this point, the mobile access gateway will have enough information to 1131 emulate the mobile node's home link. It must send the Router 1132 Advertisement messages advertising the mobile node's home network 1133 prefix and other parameters. 1135 If the access link connecting the mobile access gateway and the 1136 mobile node is a point-to-point link, the Router Advertisements 1137 advertising a specific home network prefix is received only by the 1138 respective mobile node and hence there is clearly a unique link for 1139 each mobile node that is attached to that mobile access gateway. 1141 If the access link connecting the mobile access gateway and the 1142 mobile node is a shared-link, the mobile access gateway MUST ensure 1143 that each of the mobile node that is attached to that link receives 1144 Router Advertisements with its respective home network prefix as the 1145 on-link prefix. For this to happen, the mobile access gateway MUST 1146 unicast the Router Advertisement to the mobile node. The destination 1147 field of the link-layer header in the Router Advertisement MUST be 1148 the mobile's node's interface physical/MAC address and however, the 1149 destination field in the IPv6 header set to the all-nodes-multicast 1150 address. 1152 6.5. Link-Local and Global Address Uniqueness 1154 A mobile node in a proxy mobile IPv6 domain, as it moves from one 1155 access link to the other, will continue to detect its home network 1156 and hence the issue of link-local address uniqueness arises. The 1157 link-local that the mobile node attempts to use on the new link must 1158 be unique. 1160 On a point-to-point link, such as in a PPP session, when the mobile 1161 node tries to establish a PPP session [RFC-1661] with the mobile 1162 access gateway, the PPP goes through the Network layer Protocol phase 1163 and the IPv6 Control Protocol, IPCP6 [RFC-2472] gets triggered. Both 1164 the PPP peers negotiate a unique identifier using Interface- 1165 Identifier option in IPV6CP and the negotiated identifier is used for 1166 generating a unique link-local address on that link. Now, if the 1167 mobile node moves to a new access router, the PPP session gets torn 1168 down and new PPP session with the new mobile access gateway will be 1169 established and the mobile obtains a new link-local address. Now, 1170 even if the mobile is DNAv6 capable, as specified in the DNAv6 1171 specification [draft-ietf-dna-protocol-03], the mobile node always 1172 configures a new link-local address when ever it moves to a new link. 1174 However, if the link between the mobile node and the mobile access 1175 gateway is a shared link and if a DNAv6 capable mobile node moves 1176 from one access link to the other, the mobile node may not detect a 1177 link change due to the optimizations from DNAv6 and hence there is a 1178 possibility of the link-local address collision on the connected 1179 access link, One of the work around for this issue to the set 1180 following flag on the mobile node, DNASameLinkDADFlag to TRUE and 1181 that will force the mobile node to redo DAD operation even when DNAv6 1182 detects no link change. 1184 The global address or the MN-HoA uniqueness is assured as the 1185 uniqueness is established by the local mobility anchor before 1186 accepting a proxy binding update for a mobile node. This is further 1187 assured with the currently supported per-mn-prefix model, as there 1188 are two mobile nodes that share the same home network prefix. 1189 Further, if the address configuration is based on statefull address 1190 configuration using DHCP, the DHCP server will ensure the uniqueness. 1192 6.6. IPv4 Home Address Mobility Support 1194 If the mobile node is permitted to roam using an IPv4 home address 1195 and if the mobile node has an IPv4 stack, the mobile node will be 1196 able to obtain an IPv4 MN-HoA by using DHCP address configuration 1197 procedures. As part of this address configuration, the mobile node 1198 will also be able to obtain its IPv4 home network prefix length and 1199 default-router address. The DHCP relay agent function on the access 1200 router will ensure the mobile node is assigned an address from its 1201 home network prefix, by marking the DHCP request with the mobile 1202 node's IPv4 home network prefix hint. 1204 However, the default-router address that is obtained from the DHCP 1205 will be that of the IPv4 address of its local mobility anchor and it 1206 is on a different link and not on the access link. In order for the 1207 mobile node to be able use the default-router for routing all IPv4 1208 packets, the mobile access gateway on the access link must respond to 1209 the ARP requests from the mobile node for the default-router's IPv4 1210 address. Now, if the mobile node roams to a new access link, the 1211 mobile access gateway on that link must send a gratuitous ARP for the 1212 mobile router's default-router address. 1214 In IPv6, the nodes on the link use the link-local address of the 1215 default-router for routing packets and it is not required that the 1216 default-router needs to have a configured address from the prefix 1217 that the node uses. However, in IPv4, the default-router address on 1218 the link must be from the same subnet as of the IP address of the 1219 node. Since, the mobile access gateway will not have an address on 1220 the mobile node's home prefix, it must act as a proxy for the mobile 1221 router's IPv4 gateway address. 1223 6.7. IPv4 Transport Support 1225 The network between the mobile access gateway and local mobility 1226 anchor can be an IPv4 or an IPv6 network. If the network is an IPv4 1227 network, the mobile access gateway can potentially register its IPv4 1228 care-of address for a mobility binding and thus creating an IPv4 1229 transport for carrying the mobile node's MN-HoA and IPv4 MN-HoA 1230 traffic over that tunnel. The signaling messages will always be IPv6 1231 messages encapsulated in an IPv4 packet and carried as an IPv4 1232 packet. The data traffic to and from the mobile node will also be 1233 encapulsulated in an IPv4 packet, as explained below in the Routing 1234 Considerations section. 1236 The DSMIPv6 draft [draft-ietf-mip6-nemo-v4traversal] defines a 1237 solution for allowing a mobile node to roam over an IPv4 and IPv6 1238 network. The options defined in the DSMIP6 spec, IPv4 home address 1239 option, IPv4 address acknowledgement option and the NAT detection 1240 option can all be carried in the Proxy Binding Update and 1241 Acknowledgement messages exchanged between the mobile access gateway 1242 and the local mobility anchor. As explained in Section 4.1, of the 1243 DSMIP6 spec, the mobile access gateway can encapsulate a Proxy 1244 Binding Update message and carry it in an IPv4 packet. The 1245 processing logic for handling the NAT detection at the mobile node is 1246 applicable to the mobile access gateway. 1248 6.8. Tunnel Management 1250 In the traditional Mobile IPv6 model, there is a separate tunnel from 1251 the local mobility anchor to every mobile node that has a binding 1252 cache entry. The one end-point of these tunnels is the respective 1253 mobile node's care-of address and that is unique to that mobile node. 1254 In the case of Proxy Mobile IPv6, the care-of address or the tunnel 1255 end-point is the address of the mobile access gateway and there could 1256 be multiple mobile nodes attached to the same mobile access gateway 1257 and hence the tunnel is a shared tunnel serving multiple mobile 1258 nodes. This is identical to the Mobile IPv4 model [RFC-3344], where 1259 a tunnel between the foreign agent and the home agent is shared by 1260 many visiting mobile nodes and hence the tunnel management needs to 1261 be on a global basis and not be dependent on a specific mobile node's 1262 binding. 1264 The life of the Proxy Mobile IPv6 tunnel should not be based on a 1265 single binding cache entry. The tunnel may get created as part of 1266 creating a mobility state for a mobile node and later the same tunnel 1267 may be associated with other mobile nodes. So, the tearing down 1268 logic of the tunnel must be based on the number of visitors over that 1269 tunnel. Implementations are free to pre-establish tunnels between 1270 every local mobility anchor and every mobile access gateway in a 1271 proxy mobile IPv6 domain and with out having to create and destroy 1272 the tunnels on a need basis. 1274 6.9. Routing Considerations 1276 This section describes how the data traffic to/from the mobile node 1277 is handled at the mobile access gateway. The following entries 1278 explains the routing state for the mobile node on the mobile access 1279 gateway. 1281 Mobile Node's IPv6 traffic: 1282 =========================== 1283 For all traffic from the source address MN-HoA to destination 0::/0 1284 route via tunnel0, next-hop LMAA. 1286 MN-HoA::/64 is reachable via the directly connected interface. 1288 Mobile Node's IPv4 traffic: 1289 =========================== 1290 For all IPv4 traffic from the source address IPv4 MN-HoA to 1291 destination 0.0.0.0/0.0.0.0 route via tunnel0, next-hop LMAA. 1293 IPv4-MN-HoA/32 is on the interface locally connected 1295 tunnel0: 1296 ======== 1297 Source: Proxy-CoA or IPv4 Proxy-CoA 1298 Destination: LMAA or IPv4 LMAA 1299 Tunnel Payload: IPv6 or IPv4 1300 Tunnel Transport: IPv6, IPv4 or IPv4-UDP 1302 When the mobile access gateway receives any packets from the mobile 1303 node to any destination, the packet will be forwarded to the local 1304 mobility anchor through the bi-directional tunnel established between 1305 itself and the mobile's local mobility anchor. However, the packets 1306 that are sent with link-local source address are not forwarded. 1308 If the tunnel between the mobile access gateway and local mobility 1309 anchor is an IPv6 tunnel i.e. if the registered care-of address is an 1310 IPv6 Proxy-CoA, any IPv6 packet from the mobile node with the source 1311 MN-HoA, will be encapsulated in an IPv6 packet, IPv6/IPv6 mode and 1312 will be carried as an IPv6 packet. And any IPv4 packet from the 1313 mobile node with the source IPv4 Mobile-HoA, will be encapsulated in 1314 an IPv6 packet, IPv4/IPv6 mode, and will be carried as an IPv6 1315 packet. 1317 If the tunnel between the mobile access gateway and local mobility 1318 anchor is an IPv4 tunnel i.e. if the registered care-of address is 1319 the IPv4 Proxy-CoA, any IPv6 packet from the mobile node with the 1320 source MN-HoA, will be encapsulated in an UDP header of an IPv4 1321 packet, IPv6/IP-UDP mode, and will be carried as an IPv4 packet. And 1322 any IPv4 packet from the mobile node with the source IPv4 MN-HoA, 1323 will be encapsulated in an UDP header of an IPv4 packet, IPv4/ 1324 IPv4-UDP, and will be carried as an IPv4 packet. In both these 1325 cases, the UDP header will not be there, if there is no presence of 1326 NAT devices detected on the path. 1328 All the packets that the mobile access gateway receives from the 1329 tunnel, after removing the tunnel encapsulation, will forward it to 1330 the mobile node on the connected interface. 1332 6.10. Interaction with DHCP Relay Agent 1334 If Statefull Address Configuration using DHCP is supported on the 1335 link on which the mobile node is attached, the DHCP relay agent [RFC- 1336 3315] needs to be configured on the access router. When the mobile 1337 node sends a DHCPv6 Request message, the relay agent function on the 1338 access router must set the link-address field in the DHCPv6 message 1339 to the mobile node's home network prefix, so as to provide a prefix 1340 hint to the DHCP Server. On a point-to-point link, this is just a 1341 normal DHCP relay agent configuration. However, on the shared links 1342 supporting multiple mobile nodes with different home prefixes, there 1343 is some interaction required between the relay agent and the mobile 1344 access gateway, for setting the link-address field to the requesting 1345 mobile node's home network prefix. 1347 If the mobile is permitted to roam using IPv4 home address, the 1348 DHCPv4 relay agent service [RFC-2131] needs to be configured on that 1349 link. Further, the giaddr field in the DHCPv4 Request message must 1350 be set to the mobile node's IPv4 home network prefix. 1352 6.11. Mobile Node Detachment Detection and Resource Cleanup 1354 Before sending a Proxy Binding Update message to the local mobility 1355 anchor for extending the lifetime of a currently existing binding of 1356 a mobile node, the mobile access gateway MUST make sure the mobile 1357 node is still attached to the connected link by using some reliable 1358 method. If the mobile access gateway cannot predictably detect the 1359 presence of the mobile node on the connected link, it MUST NOT 1360 attempt to extend the registration lifetime of the mobile node. 1361 Further, in such scenario, the mobile access gateway MUST terminate 1362 the binding of the mobile node by sending a Proxy Binding Update 1363 message to the mobile node's local mobility anchor with lifetime 1364 value set to 0. It MUST also remove any local state such as binding 1365 update list entry that was created for that mobile node. 1367 The specific detection mechanism of the loss of a visiting mobile 1368 node on the connected link is specific to the access link between the 1369 mobile node and the mobile access gateway and is outside the scope of 1370 this document. Typically, there are various link-layer specific 1371 events specific to each access technology that the mobile access 1372 gateway can depend on for detecting the node loss. In general, the 1373 mobile access gateway can depend on one or more of the following 1374 methods for the detection presence of the mobile node on the 1375 connected link: 1377 o Link-layer event specific to the access technology 1379 o PPP Session termination event on point-to-point link types 1381 o IPv6 Neighbor Unreachability Detection event from IPv6 stack 1383 o Notification event from the local mobility anchor 1385 o Absence of data traffic from the mobile node on the link for a 1386 certain duration of time 1388 6.12. Coexistence with Mobile Nodes using Host-based Mobility 1390 In some operating environments, network operators may want to 1391 provision the access link attached to the mobile access gateway to 1392 offer network-based mobility service only to some nodes and enable 1393 normal IP access support for some other nodes on that link. This 1394 specification supports access links with such mixture of nodes. The 1395 network has the control on when to enable the mobile node with the 1396 network mobility service. 1398 Upon obtaining the mobile node's profile after a successful access 1399 authentication and after a policy consideration, the mobile access 1400 gateway MUST determine if the network based mobility service should 1401 be offered to that mobile node. If the mobile node is entitled for 1402 such service, then the network should ensure the mobile node believes 1403 it is on its home link, as explained in various sections of this 1404 document. 1406 If the mobile node is not entitled for the network based mobility 1407 service, as determined from the policy, the mobile access gateway 1408 MUST ensure the mobile node can obtain an IPv6 address using normal 1409 IPv6 address configuration mechanisms. The obtained address should 1410 be from a local visitor network prefix. In other words the mobile 1411 node should be able to operate as a traditional mobile node roaming 1412 in a visitor network and with the ability to obtain an address from 1413 the local visitor network prefix hosted on that link. This 1414 essentially ensures, the proxy mobile IPv6 protocol will not impact 1415 the behavior of a mobile node that is using host-based mobility, as 1416 per [RFC-3775]. 1418 If the stateless address configuration mode is supported on that 1419 link, the prefix information option in the router advertisements 1420 should contain local visitor network prefix. If statefull address 1421 configuration mode is enforced on the link and if DHCP is in used, 1422 the mobile node should be able to obtain the IPv6 or IPv4 care-of 1423 address from the local visitor network prefix. 1425 If the link between the mobile access gateway and the mobile node is 1426 a shared link, the Router Advertisement has to unicasted to the 1427 mobile node with the destination address in the layer-2 header set to 1428 the mobile's MAC address and the destination address in the IPv6 1429 header set to the all-nodes multicast address. 1431 6.13. Mobile Access Gateway Operation Summary 1433 o After detecting a new mobile node on its access link and after the 1434 successful access authentication and authorization of the mobile 1435 node, the mobile access gateway MUST be able to able to access the 1436 mobile node's profile. This may be downloaded from the local/ 1437 network policy store using MN-Identity or may be obtained as part 1438 of a context transfer procedure. The mobile node's profile at the 1439 minimum MUST have the mobile node's local mobility anchor address 1440 and the MN-Identity. Optionally, it may have the mobile node's 1441 home network prefix and other configuration parameters. 1443 o The mobile access gateway MAY use one or more ways to detect the 1444 attachment of a mobile node on to the link. The techniques can be 1445 specific to the access technology or can be other generic events 1446 as mentioned in the above sections. 1448 o If the network determines that the mobile node will not be offered 1449 the network-based mobility service, the mobile access gateway MUST 1450 ensure that the Router Advertisements it sends will not contain 1451 the mobile node's home prefix, but will be the hosted on-link 1452 prefix. Also, if the mobile node attempts to obtain an IPv4/IPv6 1453 address, the mobile access gateway or the DHCP relay agent on the 1454 link MUST ensure that the prefix hint that gets added to the DHCP 1455 message will be of the local hosted prefix. 1457 o `The mobile access gateway on receiving a Router Solicitation 1458 message from a mobile node MUST send a Router Advertisement 1459 message containing the mobile node's home network prefix. 1461 o The mobile access gateway MUST send the periodic Router 1462 Advertisement messages, as per the ND specification [RFC-2461], 1463 advertising the mobile node's home network prefix on the access 1464 link. 1466 o If the link between the mobile node and the mobile access gateway 1467 is a shared-link, then the Router Advertisement MUST be unicasted 1468 to the mobile node by setting the destination address in the link- 1469 layer header to the mobile node's MAC address and with the 1470 destination address in the IPv6 header set to the all-nodes 1471 multicast address. 1473 o If the mobile node uses DHCP for address configuration, the mobile 1474 access gateway or specifically the DHCP relay agent on the link 1475 MUST ensure the DHCPv4/v6 packets are properly tagged with the 1476 sending mobile node's MN-HoA or IPv4 MN-HoA, as the prefix hint. 1478 o If IPv4 home address is supported for a given mobile node, the 1479 mobile access gateway must act as a proxy for the mobile node's 1480 IPv4 default-router and that is the address of the local mobility 1481 anchor. The mobile access gateway must be able receive all the 1482 IPv4 packets from the mobile node. The mobile access gateway MUST 1483 respond to any ARP request message from the mobile node attempting 1484 to resolve the MAC address of its default-router. The ARP reply 1485 must contain the MAC address of the mobile access gateway. 1487 o The Proxy Binding Update message that the mobile access gateway 1488 sends to the local mobility anchor, MUST have the configured IPv6 1489 address of the egress interface. The Proxy Binding Update message 1490 MUST have the NAI option identifying the mobile node, home network 1491 prefix option, IPv4 home address option and optionally the time 1492 stamp option. If the home network prefix option or the IPv4 home 1493 address option are set to value 0, the local mobility anchor will 1494 assign the home network prefix and IPv4 home address and will 1495 return them in the Proxy Binding Acknowledgment. This message 1496 MUST be protected by using IPSec security association created 1497 between the mobile access gateway and local mobility anchor. 1499 o After receiving a Proxy Binding Acknowledgment with the status 1500 code indicating the acceptance of the Binding Update, the mobile 1501 access gateway MUST setup a tunnel to the mobile node's local 1502 mobility anchor, as explained in the above sections, if there is 1503 exists no tunnel. The mobile access gateway MUST also add a 1504 default route over the tunnel for all the traffic from the mobile 1505 node. 1507 o If the local mobility anchor denies the Proxy Binding Update 1508 request, the mobile access gateways MUST NOT advertise the mobile 1509 node's home prefix on the access link and there by denying 1510 mobility service to the mobile node. 1512 o Before attempting to extend binding lifetime of a mobile node, the 1513 mobile access gateway MUST make sure the mobile node is still 1514 attached to the connected link by using some reliable method. If 1515 the mobile access gateway cannot predictably detect the presence 1516 of the mobile node on the connected link, it MUST NOT attempt to 1517 extend the registration lifetime of the mobile node. Also, it 1518 MUST terminate the binding of the mobile node by sending a Proxy 1519 Binding Update message to the mobile node's local mobility anchor 1520 with lifetime value set to 0. 1522 o At any point, if the mobile access gateway detects that the mobile 1523 node has roamed away from its access link, it MUST send a Proxy 1524 Binding Update to the local mobility anchor with the lifetime 1525 value set to 0 and it must also remove the default route over the 1526 tunnel for that mobile and also remove the Binding Update list 1527 entry and any other local state created for that mobile node. 1529 7. Mobile Node Operation 1531 The Network-based mobility scheme defined in this document, allows a 1532 mobile node to obtain IP mobility within the proxy mobile IPv6 1533 domain, with out requiring the mobile node to involve in any mobility 1534 management. 1536 When a mobile node enters a proxy mobile IPv6 domain and attached to 1537 an access link, the network identifies the mobile node as part of the 1538 access authentication and establishes an identity for the mobile 1539 node. This identity has a binding to a cryptographic state and 1540 potentially associating the mobile node's link-layer address of the 1541 attached interface. The specifics on how this is achieved is beyond 1542 the scope of this document and is very much specific to the access 1543 technology and depends on the applied security protocols in place. 1544 For all practical purposes, this document assumes that the mobile 1545 node's access to the network is secure. 1547 Once the mobile node enters a Proxy Mobile IPv6 domain and attaches 1548 to an access network, the network identifies the mobile as part of 1549 the access authentication procedure and ensures the mobile using any 1550 of the address configuration mechanisms permitted by the network for 1551 that mobile, will be able to obtain an address and move anywhere in 1552 that managed domain. From the perspective of the mobile, the entire 1553 Proxy Mobile IPv6 domain appears as a single link, the network 1554 ensures the mobile believes it is always on the same link. 1556 The mobile node can be operating in an IPv4-only mode, IPv6-only mode 1557 or in dual IPv4/IPv6 mode. Typically, the configured policy in the 1558 network determines the type of home address(es) i.e. MN-HoA, IPv4 1559 MN-HoA or both, that the network mobility is supported for. If the 1560 configured policy for a mobile node is for IPv6-only home address 1561 mobility, the mobile node will be able to obtain its MN-HoA, any 1562 where in that proxy mobile IPv6 domain and if policy allows only 1563 IPv4-only home address mobility, the mobile node will be able to 1564 obtain its IPv4 MN-HoA, any where in that domain. Similarly, if the 1565 policy permits both the IPv4 and IPv6 home address mobility, the 1566 mobile node will be able to obtain its MN-HoA and IPv4 MN-HoA and 1567 move anywhere in the network. However, if the mobile node is 1568 configured for IPv6-only mobility and if the mobile node attempts to 1569 obtain an IPv4 address configuration via DHCP mechanism, the obtained 1570 address configuration will not have any mobility properties, i.e. the 1571 obtained address will be from a local prefix and not from a prefix 1572 that is topologically anchored at the local mobility anchor and hence 1573 the mobile will loose that address as it moves to a different link. 1574 The specifics on how this is achieved is the operational logic of the 1575 mobile access gateway on the access link. 1577 7.1. Booting up in a Proxy Mobile IPv6 Domain 1579 When a mobile node moves into a proxy mobile IPv6 domain and attaches 1580 to an access link, the mobile node will present its identity, MN- 1581 Identity, to the network as part of the access authentication 1582 procedure. Once the authentication procedure is complete and the 1583 mobile node is authorized to access the network, the network or 1584 specifically the mobile access gateway on the access link will have 1585 the mobile node's profile and so it would know the mobile node's home 1586 prefix and other address configuration details and other related 1587 parameters. 1589 If the mobile node is IPv6 enabled, on attaching to the link and 1590 after access authentication, the mobile node typically would send a 1591 Router Solicitation message. The mobile access gateway on the 1592 attached link will respond to the Router Solicitation message with a 1593 Router Advertisement. The Router Advertisement will have the mobile 1594 node's home network prefix, default-router address and other address 1595 configuration parameters. The address configuration parameters such 1596 as Managed Address Configuration, Statefull Configuration flag values 1597 will typically be consistent through out that domain for that mobile 1598 node. 1600 If the Router Advertisement has the Managed Address Configuration 1601 flag set, the mobile node, as it would normally do, will send a 1602 DHCPv6 Request and the mobile access gateway on that access link will 1603 ensure, the mobile node node gets the MN-HoA as a lease from the DHCP 1604 server. 1606 If the Router Advertisement does not have the Managed Address 1607 Configuration flag set and if the mobile node is allowed to use an 1608 autoconfigured address, the mobile node will generate an interface 1609 identifier, as per the Autoconf specification [RFC-2462] or using 1610 privacy extensions as specified in Privacy Extensions specification 1611 [RFC-3041]. 1613 If the mobile node is IPv4 enabled or IPv4-only enabled, the mobile 1614 node after the access authentication, will be able to obtain the IPv4 1615 address configuration for the connected interface by using DHCPv4. 1617 Once the address configuration is complete, the mobile node will have 1618 the MN-HoA, IPv4 MN-HoA or both, that it can continue to use as long 1619 as it is with in the scope of that proxy mobile IPv6 domain. 1621 7.2. Roaming in the Proxy Mobile IPv6 Network 1623 After booting in the Proxy Mobile IPv6 domain and obtaining the 1624 address configuration, the mobile node as it roams in the network 1625 between access links, will always detect its home network prefix on 1626 the link, as long as the attached access network is in the scope of 1627 that proxy mobile IPv6 domain. The mobile node can continue to use 1628 its IPv4/IPv6 MN-HoA for sending and receiving packets. If the 1629 mobile node uses DHCP for address configuration, it will always be 1630 able to obtain its MN-HoA using DHCP. However, the mobile node will 1631 always detect a new default-router on each connected link, but still 1632 advertising the mobile node's home prefix as the on-link prefix and 1633 with the other configuration parameters consistent with the link 1634 properties as before. 1636 7.3. IPv6 Host Protocol Parameters 1638 This specification assumes the mobile node to be a normal IPv6 node, 1639 with its protocol operation consistent with the base IPv6 1640 specification [RFC-2460]. All aspects of Neighbor Discovery 1641 Protocol, including Router Discovery, Neighbor Discovery, Address 1642 Configuration procedures will just remain consistent with the base 1643 IPv6 Neighbor Discovery Specification [RFC-2461]. However, this 1644 specification recommends that the following IPv6 operating parameters 1645 on the mobile node be adjusted to the below recommended values for 1646 protocol efficiency and for achieving faster hand-offs. 1648 Lower Default-Router List Cache Time-out: 1650 As per the base IPv6 specification [RFC-2460], each IPv6 host will 1651 maintain certain host data structures including a Default-Router 1652 list. This is the list of on-link routers that have sent Router 1653 Advertisement messages and are eligible to be default routers on that 1654 link. The Router Lifetime field in the received Router Advertisement 1655 defines the life of this entry. 1657 In the Proxy Mobile IPv6 scenario, when the mobile node moves from 1658 one link to another, the received Router Advertisement messages 1659 advertising the mobile's home network prefix will be from a different 1660 link-local address and thus making the mobile node believe that there 1661 is a new default-router on the link. It is important that the mobile 1662 node uses the newly learnt default-router as supposed to the 1663 previously learnt default-router. The mobile node must update its 1664 default-router list with the new default router entry and must age 1665 out the previously learnt default router entry from its cache, just 1666 as specified in Section 6.3.5 of the base IPv6 ND specification [RFC- 1667 2461]. This action is critical for minimizing packet losses during a 1668 hand off switch 1670 On detecting a reachability problem, the mobile node will certainly 1671 detect the neighbor or the default-router unreachability by 1672 performing a Neighbor Unreachability Detection procedure, but it is 1673 important that the mobile node times out the previous default router 1674 entry at the earliest. If a given IPv6 host implementation has the 1675 provision to adjust these flush timers, still conforming to the base 1676 IPv6 ND specification, it is desirable to keep the flush-timers to 1677 suit the above consideration. 1679 However, if the mobile access gateway has the ability to with draw 1680 the previous default-router entry, by multicasting a Router 1681 Advertisement using the link-local address that of the previous 1682 mobility proxy agent and with the Router Lifetime field set to value 1683 0, then it is possible to force the flush out of the Previous 1684 Default-Router entry from the mobile node's cache. This certainly 1685 requires some context-transfer mechanisms in place for notifying the 1686 link-local address of the default-router on the previous link to the 1687 mobile access gateway on the new link. 1689 There are other solutions possible for this problem, including the 1690 assignment of a unique link-local address for all the access routers 1691 in the Proxy Mobile IPv6 Network. In either case, this is an 1692 implementation choice and has no bearing on the protocol 1693 interoperability. Implementations are free to adopt the best 1694 approach that suits their target deployments. 1696 8. Message Formats 1698 This section defines extensions to the Mobile IPv6 [RFC-3775] 1699 protocol messages. 1701 8.1. Proxy Binding Update 1703 0 1 2 3 1704 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 1705 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1706 | Sequence # | 1707 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1708 |A|H|L|K|M|R|P| Reserved | Lifetime | 1709 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1710 | | 1711 | | 1712 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1714 Figure 6: Proxy Binding Update Message 1716 A Binding Update message that is sent by mobile access gateway is 1717 referred to as the Proxy Binding Update message. 1719 Proxy Registration Flag (P) 1721 The Proxy Registration Flag is set to indicate to the local mobility 1722 anchor that the Binding Update is from a mobile access gateway acting 1723 as a proxy mobility agent. The flag MUST be set to the value of 1 1724 for proxy registrations and MUST be set to 0 for direct registration 1725 send my a mobile node using host-base mobility. 1727 For descriptions of other fields present in this message, refer to 1728 the section 6.1.7 of Mobile IPv6 specification [RFC3775]. 1730 8.2. Proxy Binding Acknowledgment 1732 0 1 2 3 1733 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 1734 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1735 | Status |K|R|P|Reserved | 1736 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1737 | Sequence # | Lifetime | 1738 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1739 | | 1740 | | 1741 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1743 Figure 7: Proxy Binding Acknowledgment Message 1745 Proxy Registration Flag (P) 1747 A new flag (P) is included in the Binding Acknowledgement message to 1748 indicate that the local mobility anchor Agent that processed the 1749 corresponding Binding Update supports Proxy Registrations. The flag 1750 is set only if the corresponding Proxy Binding Update had the Proxy 1751 Registration Flag (P) set to 1. The rest of the Binding 1752 Acknowledgement format remains the same, as defined in [RFC-3775]. 1754 For descriptions of other fields present in this message, refer to 1755 the Mobile IPv6 base specificatoin [RFC-3775]. 1757 A Binding Acknowledgment message that is sent by the mobile access 1758 gateway is also referred to as "Proxy Binding Acknowledgement". 1760 8.3. Home Network Prefix Option 1762 A new option, Home Network Prefix Option is defined for using it in 1763 the Proxy Binding Update and Acknowledgment messages exchanged 1764 between the local mobility anchor to the mobile access gateway. This 1765 option can be used for exchanging the mobile node's home prefix and 1766 home address information. 1768 The home network prefix Option has an alignment requirement of 8n+4. 1769 Its format is as follows: 1771 0 1 2 3 1772 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 1773 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1774 | Type | Length | Reserved | Prefix Length | 1775 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1776 | | 1777 + + 1778 | | 1779 + Home Network Prefix + 1780 | | 1781 + + 1782 | | 1783 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1785 Type 1786 1788 Length 1790 8-bit unsigned integer indicating the length in octets of 1791 the option, excluding the type and length fields. This field 1792 MUST be set to 18. 1794 Reserved 1796 This field is unused for now. The value MUST be initialized 1797 to 0 by the sender and MUST be ignored by the receiver. 1799 Prefix Length 1801 8-bit unsigned integer indicating the prefix length of the 1802 IPv6 prefix contained in the option. If the prefix length 1803 is set to the value 128, indicates the presence of the 1804 mobile node's 128-bit home address. 1806 Home Network Prefix 1808 A sixteen-byte field containing the Home Network Prefix 1809 Figure 8: Home Network Prefix Option 1811 8.4. Time Stamp Option 1813 A new option, Time Stamp Option is defined for use in Proxy Binding 1814 Update and Acknowledgement messages. This option MUST be present in 1815 all Proxy Binding Update and Acknowledgement messages. 1817 0 1 2 3 1818 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 1819 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1820 | Option Type | Option Length | 1821 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1822 | | 1823 + Timestamp + 1824 | | 1825 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1827 Type 1828 1830 Length 1832 8-bit unsigned integer indicating the length in octets of 1833 the option, excluding the type and length fields. This field 1834 MUST be set to 18. 1836 Timestamp 1838 64-bit time stamp 1840 Figure 9: Time Stamp Option 1842 8.5. Status Codes 1844 This document defines the following new Binding Acknowledgement 1845 status values: 1847 145: Proxy Registration not supported by the local mobility anchor 1848 146: Proxy Registrations from this mobile access gateway not allowed 1850 147: No home address for this NAI is configured and the Home Network 1851 Prefix Option not present in the Binding Update. 1853 148: Invalid Time Stamp Option in the Binding Update 1855 Status values less than 128 indicate that the Binding Update was 1856 processed successfully by the receiving nodes. Values greater than 1857 128 indicate that the Binding Update was rejected by the local 1858 mobility anchor. 1860 The value allocation for this usage needs to be approved by the IANA 1861 and must be updated in the IANA registry. 1863 9. IANA Considerations 1865 This document defines a new Mobility Header Option, the Mobile Home 1866 Network Prefix Option. This option is described in Section 8.3. The 1867 Type value for this option needs to be assigned from the same 1868 numbering space as allocated for the other mobility options defined 1869 in [RFC-3775]. 1871 This document defines a new Mobility Header Option, the Time Stamp 1872 Option. This option is described in Section 8.4. The type value for 1873 this option needs to be assigned from the same numbering space as 1874 allocated for the other mobility options defined in [RFC-3775]. 1876 This document also defines new Binding Acknowledgement status values 1877 as described in Section 8.5. The status values MUST be assigned from 1878 the same space used for Binding Acknowledgement status values in 1879 [RFC-3775]. 1881 10. Security Considerations 1883 The security threats against any general network-based mobility 1884 management protocol are covered in the document, Security Threats to 1885 Network-Based Localized Mobility Management 1886 [draft-ietf-netlmm-threats-04.txt]. This section analyses those 1887 vulnerabilities in the context of Proxy Mobile IPv6 protocol and 1888 covers all aspects around those identified vulnerabilities. 1890 A compromised mobile access gateway can send Proxy Binding Update 1891 requests for mobile nodes that are not attached to its access link. 1892 This threat is similar to an attack on a typical routing protocol or 1893 equivalent to the compromise of a on-path router and hence this 1894 threat exists in the network today and this specification does not 1895 make this vulnerability any worse than what it is. However, to 1896 eliminate this attack, the local mobility anchor can ensure that the 1897 mobile node is attached to the access link of the requesting mobile 1898 access gateway. This can be achieved using out of band mechanisms, 1899 such as from the mobile node's access authentication to the network 1900 and the specifics of how that is achieved is beyond the scope of this 1901 document. 1903 This document does not cover the security requirements for 1904 authorizing the mobile node for the use of the access link. It is 1905 assumed that there are proper Layer-2 based authentication 1906 procedures, such as EAP, in place and will ensure the mobile node is 1907 properly identified and authorized before permitting it to access the 1908 network. It is further assumed that the same security mechanism will 1909 ensure the mobile session is not hijacked by malicious nodes on the 1910 access link. 1912 This specification requires that all the signaling messages exchanged 1913 between the mobile access gateway and the local mobility anchor MUST 1914 be authenticated by IPsec [RFC-4301]. The use of IPsec to protect 1915 Mobile IPv6 signaling messages is described in detail in the HA-MN 1916 IPsec specification [RFC-3776] and the extension of that security 1917 model to Proxy Mobile IPv6 is covered in Section 4.0 of this 1918 document. 1920 As described in the base Mobile IPv6 specification [RFC-3775], 1921 Section 5.1 both the mobile client (in this case, its the mobile 1922 access gateway) and the local mobility anchor MUST support and SHOULD 1923 use the Encapsulating Security Payload (ESP) header in transport mode 1924 and MUST use a non-NULL payload authentication algorithm to provide 1925 data origin authentication, data integrity and optional anti-replay 1926 protection. 1928 The proxy solution allows one device creating a routing state for 1929 some other device at the local mobility anchor. It is important that 1930 the local mobility anchor has proper authorization services in place 1931 to ensure a given mobile access gateway is permitted to be a proxy 1932 for a specific mobile node. If proper security checks are not in 1933 place, a malicious node may be able to hijack a session or may do a 1934 denial-of-service attacks. 1936 11. Acknowledgements 1938 The authors would like to specially thank Julien Laganier, Christian 1939 Vogt, Pete McCann, Brian Haley and Ahmad Muhanna for their thorough 1940 review of this document. 1942 The authors would also like to thank the Gerardo Giaretta, Kilian 1943 Weniger, Alex Petrescu, Mohamed Khalil, Fred Templing, Nishida 1944 Katsutoshi, James Kempf, Vidya Narayanan, Henrik Levkowetz, Phil 1945 Roberts, Jari Arkko, Ashutosh Dutta, Hesham Soliman, Behcet Sarikaya, 1946 George Tsirtsis and many others for their passionate discussions in 1947 the working group mailing list on the topic of localized mobility 1948 management solutions. These discussions stimulated much of the 1949 thinking and shaped the draft to the current form. We acknowledge 1950 that ! 1952 The authors would also like to thank Ole Troan, Akiko Hattori, Perviz 1953 Yegani, Mark Grayson and Tim Stammers for their input on this 1954 document. 1956 12. Appendix-A: Proxy Mobile IPv6 Deployment Models 1958 Localized Mobility Management and Global Mobility Management can be 1959 combined in many different ways. Proxy Mobile IPv6 is typically used 1960 for localized mobility management and Mobile IPv6 is applied for 1961 global mobility management. The following section covers some of the 1962 potential deployment use-cases. However, it is to be noted that the 1963 protocol is not restricted for the given use cases. Its up to the 1964 specific architecture as how it leverages the base protocol defined 1965 in this document. 1967 |<-- Global Mobility -->| 1969 |<- Local Mobility ->| |<- Local Mobility ->| 1970 +-----+ +-----+ 1971 / \ / \ 1972 \ / \ / 1973 +-----+ +-----+ 1974 PMIPv6 Domain#2 PMIPv6 Domain#3 1975 \ / 1976 \ / 1977 \__________/ 1978 (__________) 1979 Internet 1980 | 1981 | 1982 | 1983 +-----+ 1984 / \ 1985 \ / 1986 +-----+ 1987 MIPv6 Home Domain 1988 (PMIPv6 Domain#1) 1990 Figure 10: Integrated Local and Global Mobility Management 1992 12.1. Case-1# Avoiding Global Mobility at home (MIPv6-HoA == MN-HoA) 1994 In this mode, the mobile node uses Proxy Mobile IPv6 as long as it is 1995 in the Proxy Mobile IPv6 domain. It has Mobile IPv6 stack active at 1996 the same time, but as long as it is attached to the same Proxy Mobile 1997 IPv6 domain, it will appear as if it is attached to the home link. 1998 If it attaches to an access network that is not part of the Proxy 1999 Mobile IPv6 domain, it acquires a care-of address from the access 2000 networks, treats the earlier home address in the Proxy Mobile IPv6 2001 domain as the Mobile IPv6 home address and performs a Mobile IPv6 2002 registration. The Mobile IPv6 registration is performed with the 2003 same home agent that was earlier a local mobility anchor in the Proxy 2004 Mobile IPv6 domain. Following are the key aspects of this ulti-layer 2005 mobility management scheme. 2007 The mobile node has a Mobile IPv6 home domain and is either 2008 statically configured or will be dynamically assigned with an home 2009 address (MIPv6-HoA). The home agent supporting this mobile node 2010 based on host-based mobility management scheme, is also configured to 2011 function as a local mobility anchor for supporting local mobility 2012 management. 2014 MIPv6-HoA = MN-HoA. 2016 When the mobile node is in its mobile IPv6 home domain, it will be 2017 able to roam in that domain using its MN-HoA and with out having to 2018 participate in any mobility related signaling. The domain is enabled 2019 for network-based mobility and the obtained home address in the proxy 2020 mobile IPv6 context (MN-HoA) is the same as its global home address 2021 (MIPv6-HoA). The mobile is not required to initiate host-based 2022 mobility and avoiding any IPv6 tunneling over ahead in the home 2023 domain. 2025 When the mobile moves away from its home domain and enters a domain 2026 where network-based mobility management is enabled, the mobile node 2027 can obtain an home address, MN-HoA, for that Proxy Mobile IPv6 domain 2028 and can establish mobility session with its home agent. The obtained 2029 MN-HoA in that visitor domain is valid through out that domain and 2030 the mobile node is not required to update its global mobility binding 2031 as long as it is in that domain. From the context of the global 2032 mobility session, the obtain home address in that domain is the 2033 mobile IPv6 Care-Off Address. 2035 MIPv6-CoA = MN-HoA. 2037 If the mobile node moves in to a domain, where network based mobility 2038 is not enabled, the mobile node will use the locally obtained IPv6 2039 address on the anchored link and establish global mobility management 2040 for its home address (MIPv6-HoA), using host-based mobility 2041 signaling. 2043 12.2. Case-2# Requiring Global Mobility at home (MIPv6-CoA == MN-HoA) 2045 In this model, PMIPv6 and MIPv6 are used in a hierarchical manner 2046 where proxy mobile IPv6 is used for local mobility and mobile IPv6 is 2047 used for global mobility. The MN-HoA address assigned to the mobile 2048 node in the Proxy Mobile IPv6 domain is used as the care-of address 2049 for Mobile IPv6 registration. If the mobile node moves and attaches 2050 to an access network that is not part of the proxy mobile IPv6 2051 domain, it acquires a care-of address from the access network and 2052 performs a regular Mobile IPv6 registration with its home agent. 2053 When the mobile node is outside the Proxy Mobile IPv6 domain, only 2054 Mobile IPv6 is used. 2056 The key difference between this model and the above model is the 2057 restriction of the home address obtained from the proxy mobile IPv6 2058 domain which also happens to be its mobile IPv6 home domain, to be 2059 used as a care-of address for global mobility. The mobile node 2060 cannot obtain its MIPv6-HoA as a MN-HoA, when at home and hence it 2061 always needs to establish global mobility session if sustaining 2062 sessions when moving between the domains is desired. 2064 When at home or away, where network-based mobility is enabled, the 2065 mobile node will use the locally obtained IPv6address (MIPv6-CoA) on 2066 the attached link and establish global mobility management for its 2067 home address (MIPv6-HoA), using host-based mobility signaling. 2069 13. Appendix-B: Proxy Mobile IPv6 interactions with AAA Infrastructure 2071 Every mobile node that roams in a proxy Mobile IPv6 domain, would 2072 typically be identified by an identifier, MN-Identifier, and that 2073 identifier will have an associated policy profile that identifies the 2074 mobile node's home network prefix, permitted address configuration 2075 modes, roaming policy and other parameters that are essential for 2076 providing network-based mobility service. This information is 2077 typically configured in AAA. It is possible the home network prefix 2078 is dynamically allocated for the mobile node when it boots up for the 2079 first time in the network, or it could be a statically configured 2080 value on per mobile node basis. However, for all practical purposes, 2081 the network entities in the proxy Mobile IPv6 domain, while serving a 2082 mobile node will have access to this profile and these entities can 2083 query this information using RADIUS/DIAMETER protocols. 2085 14. Appendix-C: Supporting Shared-Prefix Model using DHCPv6 2087 For supporting shared-prefix model, i.e, if multiple mobile nodes are 2088 configured with a common IPv6 network prefix, as in Mobile IPv6 2089 specification, it is possible to support that configuration under the 2090 following guidelines: 2092 The mobile node is allowed to use statefull address configuration 2093 using DHCPv6 for obtaining its address configuration. The mobile 2094 nodes is not allowed to use any of the stateless autoconfiguration 2095 techniques. The permitted address configuration models for the 2096 mobile node on the access link can be enforced by the mobile access 2097 gateway by setting the relevant flags in the Router Advertisements, 2098 as per ND Specification, [RFC-2461] 2099 The Home Network Prefix Option that is sent by the mobile access 2100 gateway in the Proxy Binding Update message, must contain the 128-bit 2101 host address that the mobile node obtained via DHCPv6. 2103 Routing state at the mobile access gateway: 2105 For all IPv6 traffic from the source MN-HoA::/128 to destination 2106 0::/0, route via tunnel0, next-hop LMAA, where tunnel0 is the MAG to 2107 LMA tunnel. 2109 Routing state at the local mobility anchor: 2111 For all IPv6 traffic to destination MN-HoA::/128, route via tunnel0, 2112 next-hop Proxy-CoA, where tunnel0 is the LMA to MAG tunnel. 2114 15. References 2116 15.1. Normative References 2118 [RFC-1305] Mills, D., "Network Time Protocol (Version 3) 2119 Specification, Implementation", RFC 1305, March 1992. 2121 [RFC-2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 2122 (IPv6) Specification", RFC 2460, December 1998. 2124 [RFC-2461] Narten, T., Nordmark, E. and W. Simpson, "Neighbor 2125 Discovery for IP Version 6 (IPv6)", RFC 2461, December 1998. 2127 [RFC-2462] Thompson, S., Narten, T., "IPv6 Stateless Address 2128 Autoconfiguration", RFC 2462, December 1998. 2130 [RFC-2473] Conta, A. and S. Deering, "Generic Packet Tunneling in 2131 IPv6 Specification", RFC 2473, December 1998. 2133 [RFC-3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C. and 2134 M.Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", 2135 RFC 3315, July 2003. 2137 [RFC-3775] Johnson, D., Perkins, C., Arkko, J., "Mobility Support in 2138 IPv6", RFC 3775, June 2004. 2140 [RFC-3776] Arkko, J., Devarapalli, V., and F. Dupont, "Using IPsec to 2141 Protect Mobile IPv6 Signaling Between Mobile Nodes and Home Agents", 2142 RFC 3776, June 2004. 2144 [RFC-4283] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K. 2145 Chowdhury, "Mobile Node Identifier Option for Mobile IPv6", RFC 4283, 2146 November 2005. 2148 [RFC-4301] Kent, S. and Atkinson, R., "Security Architecture for the 2149 Internet Protocol", RFC 4301, December 2005. 2151 [RFC-4303] Kent, S. "IP Encapsulating Security Protocol (ESP)", RFC 2152 4303, December 2005. 2154 [RFC-4306] Kaufman, C, et al, "Internet Key Exchange (IKEv2) 2155 Protocol", RFC 4306, December 2005. 2157 [draft-ietf-netlmm-nohost-req-05.txt] Kempf, J., Leung, K., Roberts, 2158 P., Nishida, K., Giaretta, G., Liebsch, M., "Goals for Network-based 2159 Localized Mobility Management", October 2006. 2161 [draft-ietf-netlmm-nohost-ps-05.txt] Kempf, J., Leung, K., Roberts, 2162 P., Nishida, K., Giaretta, G., Liebsch, M., "Problem Statement for 2163 Network-based Localized Mobility Management", September 2006. 2165 [draft-ietf-netlmm-threats-04.txt] Vogt, C., Kempf, J., "Security 2166 Threats to Network-Based Localized Mobility Management", September 2167 2006. 2169 [draft-ietf-mip6-nemo-v4traversal-03.txt] Soliman, H. et al, "Mobile 2170 IPv6 support for dual stack Hosts and Routers (DSMIPv6)", October 2171 2006. 2173 15.2. Informative References 2175 [RFC-1332] McGregor, G., "The PPP Internet Protocol Control Protocol 2176 (IPCP)", RFC 1332, May 1992. 2178 [RFC-1661] Simpson, W., Ed., "The Point-To-Point Protocol (PPP)", STD 2179 51, RFC 1661, July 1994. 2181 [RFC-2472] Haskin, D. and Allen, E., "IP version 6 over PPP", RFC 2182 2472, December 1998. 2184 [RFC-2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an 2185 IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. 2187 [RFC-3041] Narten, T. and Draves, R., "Privacy Extensions for 2188 Stateless Address Autoconfiguration in IPv6", RFC 3041, January 2001. 2190 [RFC-3344] Perkins, C., "IP Mobility Support for IPv4", RFC 3344, 2191 August 2002. 2193 [RFC-3756] Nikander, P., Kempf, J., and E. Nordmark, "IPv6 Neighbor 2194 Discovery (ND) Trust Models and Threats", RFC 3756, May 2004. 2196 [draft-iab-multilink-subnet-issues-03.txt] Thaler, D., "Multilink 2197 Subnet Issues", January 2006. 2199 [draft-ietf-dna-protocol-03] Kempf, J., et al "Detecting Network 2200 Attachment in IPv6 Networks (DNAv6)", draft-ietf-dna-protocol-03, 2201 October 2006. 2203 [draft-ietf-mip6-ikev2-ipsec-08] Devarapalli, V. and Dupont, F., 2204 "Mobile IPv6 Operation with IKEv2 and the revised IPsec 2205 Architecture", December 2006. 2207 Authors' Addresses 2209 Sri Gundavelli 2210 Cisco Systems 2211 170 West Tasman Drive 2212 San Jose, CA 95134 2213 USA 2215 Email: sgundave@cisco.com 2217 Kent Leung 2218 Cisco Systems 2219 170 West Tasman Drive 2220 San Jose, CA 95134 2221 USA 2223 Email: kleung@cisco.com 2225 Vijay Devarapalli 2226 Azaire Networks 2227 4800 Great America Pkwy 2228 Santa Clara, CA 95054 2229 USA 2231 Email: vijay.devarapalli@azairenet.com 2232 Kuntal Chowdhury 2233 Starent Networks 2234 30 International Place 2235 Tewksbury, MA 2237 Email: kchowdhury@starentnetworks.com 2239 Basavaraj Patil 2240 Nokia 2241 6000 Connection Drive 2242 Irving, TX 75039 2243 USA 2245 Email: basavaraj.patil@nokia.com 2247 Full Copyright Statement 2249 Copyright (C) The IETF Trust (2007). 2251 This document is subject to the rights, licenses and restrictions 2252 contained in BCP 78, and except as set forth therein, the authors 2253 retain all their rights. 2255 This document and the information contained herein are provided on an 2256 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 2257 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 2258 THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 2259 OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 2260 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 2261 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 2263 Intellectual Property 2265 The IETF takes no position regarding the validity or scope of any 2266 Intellectual Property Rights or other rights that might be claimed to 2267 pertain to the implementation or use of the technology described in 2268 this document or the extent to which any license under such rights 2269 might or might not be available; nor does it represent that it has 2270 made any independent effort to identify any such rights. 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