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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Missing Reference: 'MN' is mentioned on line 279, but not defined ** Obsolete normative reference: RFC 3775 (Obsoleted by RFC 6275) Summary: 2 errors (**), 0 flaws (~~), 3 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 NETLMM Working Group G. Giaretta, Ed. 3 Internet-Draft Qualcomm 4 Intended status: Informational May 03, 2010 5 Expires: November 4, 2010 7 Interactions between PMIPv6 and MIPv6: scenarios and related issues 8 draft-ietf-netlmm-mip-interactions-06 10 Abstract 12 The use of Proxy Mobile IPv6 (PMIPv6) and Mobile IPv6 (MIPv6) in the 13 same network requires some care. This document discusses scenarios 14 where such mixed usage is appropriate and points out the need for 15 interaction between the two mechanisms. Solutions and 16 recommendations to enable these scenarios are also described. 18 Requirements Language 20 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 21 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 22 document are to be interpreted as described in RFC 2119 [RFC2119]. 24 Status of this Memo 26 This Internet-Draft is submitted in full conformance with the 27 provisions of BCP 78 and BCP 79. 29 Internet-Drafts are working documents of the Internet Engineering 30 Task Force (IETF). Note that other groups may also distribute 31 working documents as Internet-Drafts. The list of current Internet- 32 Drafts is at http://datatracker.ietf.org/drafts/current/. 34 Internet-Drafts are draft documents valid for a maximum of six months 35 and may be updated, replaced, or obsoleted by other documents at any 36 time. It is inappropriate to use Internet-Drafts as reference 37 material or to cite them other than as "work in progress." 39 This Internet-Draft will expire on November 4, 2010. 41 Copyright Notice 43 Copyright (c) 2010 IETF Trust and the persons identified as the 44 document authors. All rights reserved. 46 This document is subject to BCP 78 and the IETF Trust's Legal 47 Provisions Relating to IETF Documents 48 (http://trustee.ietf.org/license-info) in effect on the date of 49 publication of this document. Please review these documents 50 carefully, as they describe your rights and restrictions with respect 51 to this document. Code Components extracted from this document must 52 include Simplified BSD License text as described in Section 4.e of 53 the Trust Legal Provisions and are provided without warranty as 54 described in the Simplified BSD License. 56 This document may contain material from IETF Documents or IETF 57 Contributions published or made publicly available before November 58 10, 2008. The person(s) controlling the copyright in some of this 59 material may not have granted the IETF Trust the right to allow 60 modifications of such material outside the IETF Standards Process. 61 Without obtaining an adequate license from the person(s) controlling 62 the copyright in such materials, this document may not be modified 63 outside the IETF Standards Process, and derivative works of it may 64 not be created outside the IETF Standards Process, except to format 65 it for publication as an RFC or to translate it into languages other 66 than English. 68 Table of Contents 70 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 71 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 72 3. Overview of the scenarios and related issues . . . . . . . . . 5 73 3.1. Issues related to scenario A.1 . . . . . . . . . . . . . . 9 74 3.2. Issues related to scenario A.2 . . . . . . . . . . . . . . 10 75 3.3. Issues related to scenario B . . . . . . . . . . . . . . . 12 76 4. Analysis of possible solutions . . . . . . . . . . . . . . . . 12 77 4.1. Solutions related to scenario A.1 . . . . . . . . . . . . 12 78 4.2. Solutions related to scenario A.2 . . . . . . . . . . . . 14 79 4.2.1. Mobility from a PMIPv6 domain to a non-PMIPv6 80 domain . . . . . . . . . . . . . . . . . . . . . . . . 15 81 4.2.2. Mobility from a non-PMIPv6 domain to a PMIPv6 82 domain . . . . . . . . . . . . . . . . . . . . . . . . 16 83 4.3. Solutions related to scenario B . . . . . . . . . . . . . 17 84 5. Security Considerations . . . . . . . . . . . . . . . . . . . 17 85 6. IANA considerations . . . . . . . . . . . . . . . . . . . . . 17 86 7. Additional Authors . . . . . . . . . . . . . . . . . . . . . . 17 87 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18 88 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 89 9.1. Normative References . . . . . . . . . . . . . . . . . . . 18 90 9.2. Informative References . . . . . . . . . . . . . . . . . . 18 91 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 19 93 1. Introduction 95 Proxy Mobile IPv6 [RFC5213] is a network based IP mobility protocol 96 standardized by IETF. In some deployment scenarios this protocol 97 will be deployed together with MIPv6 [RFC3775], for example with 98 PMIPv6 as local mobility protocol and MIPv6 as global mobility 99 protocol. While the usage of a local mobility protocol should not 100 have implications of how global mobility is managed, since PMIPv6 is 101 partially based on MIPv6 signaling and data structure, some 102 considerations are needed to understand how the protocols interact 103 and how the different scenarios can be enabled. 105 Some standardization fora are also investigating more complex 106 scenarios where the mobility of some nodes is handled using Proxy 107 Mobile IPv6, while other nodes use Mobile IPv6; or the mobility of a 108 node is managed in turn by a host-based and a network-based 109 mechanism. This needs also to be analyzed as a possible deployment 110 scenario. 112 This document provides a taxonomy of the most common scenarios that 113 require direct interaction between MIPv6 and PMIPv6. The list is not 114 meant to be exhaustive. Moreover, this document presents and 115 identifies all issues pertained to these scenarios and discusses 116 possible means and mechanisms that are recommended to enable them. 118 2. Terminology 120 General mobility terminology can be found in [RFC3753]. The 121 following acronyms are used in this document: 123 MN-HoA: the home address of a mobile node in a Proxy Mobile IPv6 124 domain. 126 MN-HNP: the IPv6 prefix that is always present in the Router 127 Advertisements that the mobile node receives when it is attached 128 to any of the access links in that Proxy Mobile IPv6 domain. MN- 129 HoA always belongs to this prefix. 131 MIPv6-HoA: the Home Address the MN includes in MIPv6 binding 132 update messages. 134 MIPv6-CoA: the Care-of Address the MN includes in MIPv6 binding 135 update messages. 137 3. Overview of the scenarios and related issues 139 Several scenarios can be identified where Mobile IPv6 and Proxy 140 Mobile IPv6 are deployed in the same network. This document does not 141 only focus on scenarios where the two protocols are used by the same 142 mobile node to manage local and global mobility, but it investigates 143 also more complex scenarios where the protocols are more tightly 144 integrated or where there is a co-existence of nodes which do or do 145 not implement Mobile IPv6. 147 In particular the scenario space can be split into hierarchical 148 deployments and alternative deployments of Mobile IP and Proxy Mobile 149 IP. Hierarchical deployments are scenarios where the two mobility 150 protocols are used in the same network in a hierarchical manner for 151 global and local mobility management. Alternative deployments are 152 scenarios where only one of the two protocols is used for mobility 153 management of a given mobile node. 155 The following hierarchical scenarios are identified: 157 o Scenario A.1 - in this scenario Proxy Mobile IPv6 is used as a 158 network based local mobility management protocol whereas Mobile 159 IPv6 is used as a global mobility management protocol. This 160 interaction is very similar to the HMIPv6-MIPv6 interaction; 161 Mobile IPv6 is used to manage mobility among different access 162 networks, while the mobility within the access network is handled 163 by Proxy Mobile IPv6. The address managed by PMIPv6 (i.e. the MN- 164 HoA) is registered as Care-of Address by the MN at the HA. This 165 means that the HA has a binding cache entry for MIPv6-HoA that 166 points to the MN-HoA. 168 The following figure illustrates this scenario. 170 +----+ 171 | HA | MIPv6-HoA -> MN-HoA 172 +----+ 173 /\ 174 / \ 175 +-------------/----\--------------+ 176 ( / \ ) Global Mobile IPv6 177 ( / \ ) Domain 178 +----------/----------\-----------+ 179 / \ 180 +----+ +----+ 181 MN-HoA -> MAG1 |LMA1| |LMA2| 182 +----+ +----+ 183 //\\ \\ 184 +----//--\\---+ +-----\\------+ 185 ( // \\ ) ( \\ ) Local Mobility Network 186 ( // \\ ) ( \\ ) PMIPv6 domain 187 +-//--------\\+ +--------\\---+ 188 // \\ \\ 189 // \\ \\ 190 // \\ \\ 191 +----+ +----+ +----+ 192 |MAG1| |MAG2| |MAG3| 193 +----+ +----+ +----+ 194 | | | 195 [MN] 197 Figure 1 - Scenario A.1 199 o Scenario A.2 - in this scenario the mobile node is moving across 200 different access networks, some of them supporting Proxy Mobile 201 IPv6 and some others not supporting it. Therefore the mobile node 202 is roaming from an access network where the mobility is managed 203 through a network-based solution to an access network where a 204 host-based management (i.e. Mobile IPv6) is needed. This 205 scenario may have different sub-scenarios depending on the 206 relations between the Mobile IPv6 home network and the Proxy 207 Mobile IPv6 domain. The following figure illustrates an example 208 of this scenario, where the MN is moving from an access network 209 where PMIPv6 is supported (i.e. MAG functionality is supported) 210 to a network where PMIPv6 is not supported (i.e. MAG 211 functionality is not supported by the AR). This implies that the 212 home link of the MN is actually a PMIPv6 domain. In this case the 213 MIPv6-HoA is equal to the MN-HoA (i.e. the address managed by 214 PMIPv6). 216 MIPv6-HoA == MN-HoA -> MAG1 217 +------+ 218 |HA/LMA|-----------------------+ 219 +------+ | 220 //\\ | 221 +-------//--\\--------+ | 222 ( // \\ PMIPv6 ) | 223 ( // \\ domain) +--------------+ 224 +----//--------\\-----+ ( Non-PMIPv6 ) 225 // \\ ( domain ) 226 // \\ +--------------+ 227 // \\ | 228 +----+ +----+ +----+ 229 |MAG1| |MAG2| | AR | 230 +----+ +----+ +----+ 231 | | | 232 [MN] 234 Figure 3 - Scenario A.2 236 In the above figure the non-PMIPv6 domain can actually be also a 237 different PMIPv6 domain that handles a different MN_HoA. The 238 following figure illustrates this sub-case: the MIPv6-HoA is equal 239 to the MN_HoA; however when the MN hands over to MAG3 it gets a 240 different IP address (managed by LMA2 using PMIPv6) and registers 241 it as a MIPv6 CoA. 243 MIPv6-HoA == MN-HoA -> MAG_1 244 +-------+ 245 |HA/LMA1|-----------------------+ 246 +-------+ | 247 //\\ +----+ 248 +-------//--\\--------+ |LMA2| 249 ( // \\ home ) +----+ 250 ( // \\ PMIPv6) +------||------+ 251 ( // \\domain) ( ||visited) 252 +---//----------\\----+ ( ||PMIPv6 ) 253 // \\ ( ||domain ) 254 // \\ +------||------+ 255 +----+ +----+ +----+ 256 |MAG1| |MAG2| |MAG3| 257 +----+ +----+ +----+ 258 | | | 259 [MN] 261 (a) 263 MIPv6-HoA -> MN_CoA 264 +-------+ 265 |HA/LMA1|-----------------------+ 266 +-------+ | 267 //\\ +----+ 268 +-------//--\\--------+ |LMA2| MN_CoA -> MAG3 269 ( // \\ home ) +----+ 270 ( // \\ PMIPv6) +------||------+ 271 ( // \\domain) ( ||visited) 272 +---//----------\\----+ ( ||PMIPv6 ) 273 // \\ ( ||domain ) 274 // \\ +------||------+ 275 +----+ +----+ +----+ 276 |MAG1| |MAG2| |MAG3| 277 +----+ +----+ +----+ 278 | | | 279 [MN] 281 (b) 283 Figure 4 - Scenario A.2 with visited PMIPv6 domain 285 The following alternative deployment has been identified: 287 Scenario B - in this scenario some mobile nodes use Mobile IPv6 to 288 manage their movements while others rely on a network-based mobility 289 solution provided by the network as they don't support Mobile IPv6. 290 There may be a common mobility anchor that acts as Mobile IPv6 Home 291 Agent and Proxy Mobile IPv6 LMA, depending on the type of the node as 292 depicted in the figure. However, the LMA and HA can be also 293 separated and this has no impacts to the mobility of the nodes. 295 +--------+ 296 | HA/LMA | 297 +--------+ 299 +------+ +------+ 300 | MAG1 | | MAG2 | 301 +------+ +------+ 303 +-----------+ 304 | IPv6 host | -----------------> 305 +-----------+ movement 306 +----------+ 307 | MIPv6 MN | -----------------> 308 +----------+ movement 310 Figure 2 - Scenario B 312 Note that some of the scenarios can be combined. For instance, 313 scenario B can be combined with scenario A.1 or scenario A.2. 315 The following sections describe some possible issues for each 316 scenario. Respective recommendations are described in Section 4.3. 317 The specifications considered as a baseline for the analysis are the 318 following: [RFC3775], [RFC4877] and [RFC5213]. 320 3.1. Issues related to scenario A.1 322 This scenario is very similar to other hierarchical mobility schemes, 323 including a HMIPv6-MIPv6 scheme. No issues have been identified in 324 this scenario. Note that a race condition where the MN registers the 325 CoA at the HA before the CoA is actually bound to the MAG at the LMA 326 is not possible. The reason is that per PMIPv6 specification the MAG 327 does not forward any packets sent by the MN until the PMIPv6 tunnel 328 is up, regardless the mechanism used for address allocation. 330 Section 4.1 describes one message flow in case PMIPv6 is used as a 331 local mobility protocol and MIPv6 is used as a global mobility 332 protocol. 334 3.2. Issues related to scenario A.2 336 This section highlights some considerations that are applicable to 337 scenario A.2. 339 1. HoA management and lookup key in the binding cache 341 * In MIPv6 [RFC3775] the lookup key in the Binding Cache is the 342 Home Address of the MN. In particular, based on the base 343 specification [RFC3775], the MN does not include any 344 identifier, such as the MN-ID [RFC4283], in the Binding Update 345 message other than its Home Address. As described in 346 [RFC4877], the identifier of the MN is known by the Home Agent 347 after the IKEv2 exchange, but this is not used in the MIPv6 348 signaling, nor as a lookup key for the binding cache. On the 349 other hand, as specified in [RFC5213], a Proxy Binding Update 350 contains the Home Prefix of the MN, the MN-ID and does not 351 include the Home Address of the MN (since it may not be known 352 by the MAG and consequently by the HA/LMA). The lookup key in 353 the binding cache of the LMA is either the home prefix or the 354 MN-ID. This implies that lookup keys for MIPv6 and PMIPv6 355 registrations are different. Because of that, when the MN 356 moves from its home network (i.e. from the PMIPv6 domain) to 357 the foreign link, the Binding Update sent by the MN is not 358 identified by the HA as an update of the Proxy Binding Cache 359 Entry containing the home prefix of the MN, but a new binding 360 cache entry is created. Therefore PMIPv6 and MIPv6 will 361 always create two different binding cache entries in the HA/ 362 LMA which implies that the HA and LMA are logically separated. 363 How to handle the presence of the two binding cache entries 364 for the same MN is described in Section 4.2. 366 2. MIPv6 de-registration Binding Update deletes PMIPv6 binding cache 367 entry 369 * When the mobile node moves from a MIPv6 foreign network to the 370 PMIPv6 home domain, the MAG registers the mobile node at the 371 LMA by sending a Proxy Binding Update. Subsequently, the LMA 372 updates the mobile node's binding cache entry with the MAG 373 address and the MAG emulates the mobile node's home link. 374 Upon detection of the home link, the mobile node will send a 375 de-registration Binding Update to its home agent. It is 376 necessary to make sure that the de-registration of the MIPv6 377 BU does not change the PMIPv6 binding cache entry just created 378 by the MAG. 380 3. Race condition between Binding Update and Proxy Binding Update 381 messages (Sequence Numbers and Timestamps) 383 * MIPv6 and PMIPv6 use different mechanisms for handling re- 384 ordering of registration messages and they are sent by 385 different entities. In MIPv6, Binding Update messages that 386 are sent by the mobile node to the home agent are ordered by 387 the sequence numbers. The other side, in PMIP, Proxy Binding 388 Update messages that are sent by the MAG to the LMA are 389 ordered by a timestamp option. When the mobile node moves 390 from one access where Mobile IP is used to another access when 391 Proxy Mobile IP is used, delay in the mobility signaling sent 392 may imply adverse situations. For example if the mobile node 393 sends a Mobile IP binding update from access A before moving 394 to access B and this binding update gets delayed (e.g. a 395 refresh binding update), the binding update may reach the 396 combined LMA/HA after the proxy binding update sent by the 397 MAG, re-directing packets to access A even after the mobile 398 has moved to access B. 400 4. Threat of compromised MAG 402 * In MIPv6 base specification [RFC3775] there is a strong 403 binding between the Home Address registered by the mobile node 404 and the Security Association used to modify the corresponding 405 binding cache entry. 407 * In PMIPv6 specification, the MAG sends proxy binding updates 408 on behalf of a mobile node to update the binding cache entry 409 that corresponds to the mobile node's home address. Since the 410 MAG sends the binding updates, PMIPv6 requires security 411 associations between each MAG and the LMA. 413 * As described in [RFC4832], in PMIPv6 the MAG compromise or 414 impersonation is an issue. RFC4832, section 2.2, describes 415 how a compromised MAG can harm the functionality of LMA, e.g. 416 manipulating LMA's routing table (or binging cache). 418 * In this mixed scenario, both host-based and network-based 419 security associations are used to update the same binding 420 cache entry at the HA/LMA (but see the first bullet of this 421 list, as the entry may not be the same). Based on this 422 consideration, the threat described in [RFC4832] is worse as 423 it affects also hosts that are using the LMA/HA as MIPv6 HA 424 and are not using PMIPv6 426 3.3. Issues related to scenario B 428 In this scenario there are two types of nodes in the access network: 429 some nodes support Mobile IPv6 while some others do not. The 430 rationale behind such a scenario is that the nodes implementing 431 Mobile IPv6 manage their own mobility to achieve better performance, 432 e.g. for inter-technology handovers. Obviously, nodes that do not 433 implement MIPv6 must rely on the network to manage their mobility: 434 therefore Proxy MIPv6 is used for those nodes. 436 Based on the current PMIPv6 solution described in [RFC5213], in any 437 link of the PMIPv6 domain the MAG emulates the mobile node's home 438 link, advertising the home link prefix to the MN in a unicast Router 439 Advertisement message. This ensures that the IP address of the MN is 440 still considered valid by the MN itself. The home network prefix 441 (and any other information needed to emulate the home link) is 442 included in the mobile node's profile that is obtained by the MAG via 443 context transfer or via a policy store. 445 However, in case there are nodes that implement Mobile IPv6 and want 446 to use this protocol, the network must offer MIPv6 service to them. 447 In such case the MAG should not emulate the home link. Instead of 448 advertising the MN-HNP, the MAG should advertise the topologically 449 correct local IP prefix, i.e. the prefix belonging to the MAG, so 450 that the MN detects an IP movement, configures a new CoA and sends a 451 MIPv6 Binding Update based on [RFC3775]. 453 4. Analysis of possible solutions 455 4.1. Solutions related to scenario A.1 457 As mentioned in Section 3.1, there are no significant issues in this 458 scenario. 460 Figures 5 and 6 show a scenario where a mobile node is moving from 461 one PMIPv6 domain to another, based on the scenario of Figure 1. In 462 Figure 5, the mobile node moves from an old MAG to MAG2 in the same 463 PMIPv6 domain: this movement triggers a PBU to LMA1 and the updating 464 of the binding cache at the LMA1; there is no MIPv6 signaling as the 465 CoA_1 registered at the HA is the Home Address for the PMIPv6 466 session. In Figure 6, the mobile node moves from MAG2 in the LMA1 467 PMIPv6 domain to MAG3 in a different PMIPv6 domain: this triggers the 468 PMIPv6 signaling and the creation of a binding at the LMA2. On the 469 other hand, the local address of the mobile node is changed, as the 470 LMA has changed, and therefore the mobile node sends a MIPv6 Binding 471 Update to the HA with the new CoA_2. 473 +----+ +------+ +------+ +----+ 474 | MN | | MAG2 | | LMA1 | | HA | 475 +----+ +------+ +------+ +----+ 476 | | | | 477 | | | +-----------------+ 478 | | | | HoA -> CoA_1 | 479 | | | | binding present | 480 | | | +-----------------+ 481 | | | | 482 | CoA conf/confirm | PBU(CoA_1,MAG_2) | | 483 | <--------------->| ----------------->| | 484 | | +-----------------+| 485 | | | CoA_1 -> MAG_2 || 486 | | | binding updated || 487 | | +-----------------+| 488 | | PBA | | 489 | | <----------------| | 490 | | | | 492 Figure 5 - Local Mobility Message Flow 494 +----+ +------+ +------+ +----+ 495 | MN | | MAG3 | | LMA2 | | HA | 496 +----+ +------+ +------+ +----+ 498 | CoA config | PBU(CoA_2,MAG_3) | | 499 |<---------------->|------------------->| | 500 | | +-----------------+ | 501 | | | CoA_2 -> MAG_3 | | 502 | | | binding created | | 503 | | +-----------------+ | 504 | | PBA | | 505 | |<-------------------| | 506 | | | | 507 | | BU (HoA, CoA_2) | | 508 |---------------------------------------------------->| 509 | | | | 510 | | | +-----------------+ 511 | | | | HoA -> CoA_2 | 512 | | | | binding updated | 513 | | | +-----------------+ 514 | | BA | | 515 |<----------------------------------------------------| 517 Figure 6 - Global Mobility Message Flow 519 4.2. Solutions related to scenario A.2 521 As described in Section 3.2, in this scenario the mobile node relies 522 on Proxy Mobile IPv6 as long as it is in the Proxy Mobile IPv6 523 domain. The mobile node then uses Mobile IPv6 whenever it moves out 524 of the PMIPv6 domain which basically implies that the MIPv6 home link 525 is a PMIPv6 domain. 527 Analyzing the issues described in Section 3.2, it is clear that most 528 of them are applicable only to the case where there is a common 529 binding cache entry for the PMIPv6 registration and the MIPv6 530 registration. The issue 1 on how the two protocols identify the 531 binding cache entry is valid only in case we assume that a PMIPv6 532 message has any value for a MIPv6 BCE. Also the issues 2 and 3 are 533 not applicable in case different logical BCEs are used by the LMA and 534 the HA. For this reason, it is recommended that when the MIPv6 home 535 link is implemented as a PMIPv6 domain, the HA/LMA implementation 536 treats the two protocol as independent. 538 More in details the following principles should be followed by the 539 HA/LMA implementation: 541 o PMIPv6 signaling does not overwrite any MIPv6 BCE. In particular, 542 when a PMIPv6 binding cache entry is created for a mobile node 543 which has previously created a MIPv6 BCE, the MIPv6 binding cache 544 entry of the MN is not overwritten and a new PMIPv6 binding cache 545 entry is created. 547 o The downlink packets in the case where both the MIPv6 binding 548 cache entry and PMIPv6 binding cache entry exist are processed as 549 follows: 551 1. The MIPv6 binding cache entry is processed first. If the 552 destination address of the received downlink packet matches 553 the the binding cache entry of the HA, the packet is forwarded 554 by encapsulating it with the care-of-address contained in the 555 BCE. 557 2. If the destination address does not match the MIPv6 BCE, the 558 binding cache entry created by PMIPv6 is applied and the 559 packet are encapsualted to the registered MAG. 561 The following subsections provide a description of the procedures 562 which will be followed by the mobile node and HA/LMA based on the 563 above principles. The analysis is performed in two different 564 subsections, depending if the mobile node moves from a PMIPv6 domain 565 to a non-PMIPv6 domain or vice versa. 567 4.2.1. Mobility from a PMIPv6 domain to a non-PMIPv6 domain 569 Let's assume the mobile node is attached to a PMIPv6 domain and there 570 is a valid Proxy Binding Cache entry at the LMA. Then the mobile 571 node moves to a different access network and starts using MIPv6 (e.g. 572 because PMIPv6 is not supported). The mobile node needs to bootstrap 573 MIPv6 parameters and send a MIPv6 Binding Update in order to have 574 service continuity. Therefore the following steps must be performed 575 by the UE: 577 o HA/LMA address discovery: the mobile node needs to discover the IP 578 address of the LMA which has a valid binding cache entry for its 579 home network prefix. This is described in Section 3.2 as issue 4. 581 o Security Association establishment: the mobile node needs to 582 establish an IPsec Security Association with the HA/LMA as 583 described in [RFC4877] 585 o HoA or home network prefix assignment: as part of the MIPv6 586 bootstrapping procedure the HA assigns a MIPv6 HoA to the MN. 587 This address must be the same the mobile node was using in the 588 PMIPv6 domain. 590 Since all these steps must be performed by the mobile node before 591 sending the Binding Update, they have an impact on the handover 592 latency experienced by the MN. For this reason it is recommended 593 that the mobile node establishes the IPsec security association (and 594 consequently is provided by the HA/LMA with a MIPv6-HoA) when it is 595 initialized. This implies that the mobile node has Mobile IPv6 stack 596 active while in the PMIPv6 domain, but as long as it is attached to 597 the same Proxy Mobile IPv6 domain, it will appear to the mobile node 598 as if it is attached to the home link. 600 In order to establish the security association with the HA/LMA, the 601 mobile node needs to discover the IP address of the LMA/HA while in 602 the PMIPv6 domain. This can be done either based on DNS or based on 603 DHCPv6, as described in [RFC5026] and [boot-integrated]. The network 604 should be configured so that the mobile node discovers or gets 605 assigned the same HA/LMA that was serving as the LMA in the PMIPv6 606 domain. Details of the exact procedure are out of scope of this 607 document. 609 When the mobile node establishes the security association, it 610 acquires a home address based on [RFC5026]. However, based on PMIPv6 611 operations, the LMA knows only the Home Network Prefix used by the 612 mobile node and does not know the MN-HoA.For this reason, the mobile 613 node must be configured to propose MN-HoA as the home address in the 614 IKEv2 INTERNAL_IP6_ADDRESS attribute during the IKEv2 exchange with 615 the HA/LMA. Alternatively the HA/LMA can be configured to provide 616 the entire Home Network Prefix via the MIP6_HOME_LINK attribute to 617 the mobile node as specified in [RFC5026]; based on this Home Network 618 Prefix the mobile node can configure a home address. Note that the 619 security association must be bound to the MN-HoA used in the PMIPv6 620 domain as per [RFC4877]. Note that the home network prefix is shared 621 between the LMA and HA and this implies that there is an interaction 622 between the LMA and the HA in order to assign a common home network 623 prefix when triggered by PMIPv6 and MIPv6 signaling 625 When the mobile node hands over to an access network which does not 626 support Proxy Mobile IPv6, it sends a Binding Update to the HA. The 627 mobile node may set the R bit defined in NEMO specification (implicit 628 mode) in order to indicate that the entire HNP is moved to the new 629 CoA. A MIPv6 binding cache entry is created irrespective of the 630 existing PMIPv6 BCE. Packets matching the MIPv6 binding cache entry 631 are sent to the CoA present in the MIPv6 BCE. The PMIPv6 binding 632 cache entry will expire in case the MAG does not send a refresh PBU. 634 4.2.2. Mobility from a non-PMIPv6 domain to a PMIPv6 domain 636 In this section it is assumed that the mobile node is in a non-PMIPv6 637 access network and it has bootstrapped MIPv6 operations based on 638 [RFC5026]; therefore there is valid binding cache for its MIPv6-HoA 639 (or HNP in case of NEMO) at the HA. Then the mobile node moves to a 640 PMIPv6 domain which is configured to be the home link for the MIPv6- 641 HoA the mobile node has been assigned. 643 In order to provide session continuity, the MAG needs to send a PBU 644 to the HA/LMA that was serving the MN. The MAG needs to discover the 645 HA/LMA; however the current version of [RFC5213] assumes that the LMA 646 is assigned to the MAG or discovered by the MAG when the mobile node 647 attaches to the MAG. the exact mechanism is not specified in 648 [RFC5213]. A detailed description of the necessary procedure is out 649 of the scope of this document. Note that the MAG may also rely on 650 static configuration or lower layer information provided by the 651 mobile node in order to select the correct HA/LMA. 653 The PBU sent by the MAG creates a PMIPv6 binding cache entry for the 654 mobile node which is independent of the MIPv6 BCE. Traffic destined 655 to the MIPv6-HoA (or to the HNP in case the mobile node had set the 656 flag R in the last BU) is still forwarded to the CoA present in the 657 MIPv6 BCE. When the mobile node wants to use the HoA directly from 658 the home link, it sends a de-registration message and at that point 659 only the PMIPv6 binding cache entry is present. 661 4.3. Solutions related to scenario B 663 The solution for this scenario depends on the access network being 664 able to determine that a particular mobile node wants to use Mobile 665 IPv6. This requires a solution at the system level for the access 666 network and may require knowledge of the detailed configuration and 667 software capabilities of every mobile node in the system. These 668 issues are out of scope of this document 670 5. Security Considerations 672 Scenarios A.1 and B described in Section 3 do not introduce any 673 security considerations in addition to those described in [pmipv6- 674 draft] or [RFC3775]. 676 This document requires that the a home agent that also implements the 677 PMIPv6 LMA functionality should allow both the mobile node and the 678 authorized MAGs to modify the binding cache entries for the mobile 679 node. Note that the compromised MAG threat described in [RFC4832] 680 applies also here. 682 6. IANA considerations 684 This document has no IANA actions. 686 7. Additional Authors 688 Chowdhury, Kuntal - kchowdhury@starentnetworks.com 690 Hesham Soliman - Hesham@elevatemobile.com 692 Vijay Devarapalli - vijay.devarapalli@azairenet.com 694 Sri Gundavelli - sgundave@cisco.com 696 Kilian Weniger - Kilian.Weniger@googlemail.com 698 Genadi Velev - Genadi.Velev@eu.panasonic.com 700 Ahmad Muhanna - amuhanna@nortel.com 702 George Tsirtsis - tsirtsis@googlemail.com 704 Suresh Krishnan - suresh.krishnan@ericsson.com 706 8. Acknowledgements 708 This document is a merge of four different Internet Drafts: 709 draft-weniger-netlmm-pmipv6-mipv6-issues-00, 710 draft-devarapalli-netlmm-pmipv6-mipv6-01, 711 draft-tsirtsis-logically-separate-lmaha-01and 712 draft-giaretta-netlmm-mip-interactions-00. Thanks to the authors and 713 editors of those drafts. 715 The authors would also like to thank Jonne Soininen and Vidya 716 Narayanan, NETLMM WG chairs, for their support. 718 9. References 720 9.1. Normative References 722 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 723 Requirement Levels", BCP 14, RFC 2119, March 1997. 725 [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support 726 in IPv6", RFC 3775, June 2004. 728 [RFC4832] Vogt, C. and J. Kempf, "Security Threats to Network-Based 729 Localized Mobility Management (NETLMM)", April 2007. 731 [RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with 732 IKEv2 and the Revised IPsec Architecture", 2005. 734 [RFC5026] Giaretta, G., Kempf, J., and V. Devarapalli, "Mobile IPv6 735 Bootstrapping in Split Scenario", RFC 5026, October 2007. 737 [RFC5213] Gundavelli, S., "Proxy Mobile IPv6", August 2008. 739 [boot-integrated] 740 Chowdhury, K., Ed., "MIP6-bootstrapping for the Integrated 741 Scenario", 2007. 743 9.2. Informative References 745 [RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology", 746 RFC 3753, June 2004. 748 [RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K. 749 Chowdhury, "Mobile Node Identifier Option for Mobile IPv6 750 (MIPv6)", RFC 4283, November 2005. 752 Author's Address 754 Gerardo Giaretta (editor) 755 Qualcomm 757 Email: gerardog@qualcomm.com