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(See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (May 1, 2009) is 5471 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- == Missing Reference: 'MN' is mentioned on line 276, but not defined == Missing Reference: 'RFC4830' is mentioned on line 294, but not defined == Unused Reference: 'RFC4831' is defined on line 731, but no explicit reference was found in the text ** Obsolete normative reference: RFC 3775 (Obsoleted by RFC 6275) Summary: 3 errors (**), 0 flaws (~~), 5 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 1, 2009 5 Expires: November 2, 2009 7 Interactions between PMIPv6 and MIPv6: scenarios and related issues 8 draft-ietf-netlmm-mip-interactions-03 10 Status of this Memo 12 This Internet-Draft is submitted to IETF in full conformance with the 13 provisions of BCP 78 and BCP 79. 15 Internet-Drafts are working documents of the Internet Engineering 16 Task Force (IETF), its areas, and its working groups. Note that 17 other groups may also distribute working documents as Internet- 18 Drafts. 20 Internet-Drafts are draft documents valid for a maximum of six months 21 and may be updated, replaced, or obsoleted by other documents at any 22 time. It is inappropriate to use Internet-Drafts as reference 23 material or to cite them other than as "work in progress." 25 The list of current Internet-Drafts can be accessed at 26 http://www.ietf.org/ietf/1id-abstracts.txt. 28 The list of Internet-Draft Shadow Directories can be accessed at 29 http://www.ietf.org/shadow.html. 31 This Internet-Draft will expire on August 19, 2009. 33 Abstract 35 The scenarios where Proxy Mobile IPv6 (PMIPv6) and Mobile IPv6 36 (MIPv6) protocols are both deployed in a network require some 37 analysis and considerations. This document describes all identified 38 possible scenarios, which require an interaction between PMIPv6 and 39 MIPv6 and discusses all issues related to these scenarios. Solutions 40 and recommendations to enable these scenarios are also described. 42 Requirements Language 44 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 45 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 46 document are to be interpreted as described in RFC 2119 [RFC2119]. 48 Table of Contents 50 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 51 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 52 3. Overview of the scenarios and related issues . . . . . . . . . 4 53 3.1. Issues related to scenario A . . . . . . . . . . . . . . . 9 54 3.2. Issues related to scenario B . . . . . . . . . . . . . . . 9 55 3.3. Issues related to scenario C . . . . . . . . . . . . . . . 10 56 4. Analysis of possible solutions . . . . . . . . . . . . . . . . 12 57 4.1. Solutions related to scenario A . . . . . . . . . . . . . 12 58 4.2. Solutions related to scenario B . . . . . . . . . . . . . 14 59 4.3. Solutions related to scenario C . . . . . . . . . . . . . 14 60 4.3.1. Mobility from a PMIPv6 domain to a non-PMIPv6 61 domain . . . . . . . . . . . . . . . . . . . . . . . . 15 62 4.3.2. Mobility from a non-PMIPv6 domain to a PMIPv6 63 domain . . . . . . . . . . . . . . . . . . . . . . . . 16 64 5. Security Considerations . . . . . . . . . . . . . . . . . . . 17 65 6. Additional Authors . . . . . . . . . . . . . . . . . . . . . . 17 66 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17 67 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 68 8.1. Normative References . . . . . . . . . . . . . . . . . . . 18 69 8.2. Informative References . . . . . . . . . . . . . . . . . . 18 70 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 18 71 Intellectual Property and Copyright Statements . . . . . . . . . . 20 73 1. Introduction 75 Proxy Mobile IPv6 [RFC5213] is a network based IP mobility protocol 76 standardized by IETF. In some deployment scenarios this protocol 77 will be deployed together with MIPv6 [RFC3775], for example with 78 PMIPv6 as local mobility protocol and MIPv6 as global mobility 79 protocol. While the usage of a local mobility protocol should not 80 have implications of how global mobility is managed, since PMIPv6 is 81 partially based on MIPv6 signaling and data structure, some 82 considerations are needed to understand how the protocols interact 83 and how the different scenarios can be enabled. 85 Some SDOs are also investigating more complex scenarios where the 86 mobility of some nodes is handled using Proxy Mobile IPv6, while 87 other nodes use Mobile IPv6; or the mobility of a node is managed in 88 turn by a host-based and a network-based mechanism. This needs also 89 to be analyzed as a possible deployment scenario. 91 This document provides a taxonomy of all scenarios that require 92 direct interaction between MIPv6 and PMIPv6. Moreover, this document 93 presents and identifies all issues pertained to these scenarios and 94 discusses possible means and mechanisms that are recommended to 95 enable them. 97 2. Terminology 99 General mobility terminology can be found in [RFC3753]. The 100 following acronyms are used in this document: 102 MN-HoA: the home address of a mobile node in a Proxy Mobile IPv6 103 domain. 105 MN-HNP: the IPv6 prefix that is always present in the Router 106 Advertisements that the mobile node receives when it is attached 107 to any of the access links in that Proxy Mobile IPv6 domain. MN- 108 HoA always belongs to this prefix. 110 MIPv6-HoA: the Home Address the MN includes in MIPv6 binding 111 update messages. 113 MIPv6-CoA: the Care-of Address the MN includes in MIPv6 binding 114 update messages. 116 3. Overview of the scenarios and related issues 118 Several scenarios can be identified where Mobile IPv6 and Proxy 119 Mobile IPv6 are deployed in the same network. This document does not 120 only focus on scenarios where the two protocols are used by the same 121 mobile node to manage local and global mobility, but it investigates 122 also more complex scenarios where the protocols are more tightly 123 integrated or where there is a co-existence of nodes which do or do 124 not implement Mobile IPv6. 126 The following scenarios are identified: 128 o Scenario A - in this scenario Proxy Mobile IPv6 is used as a 129 network based local mobility management protocol whereas Mobile 130 IPv6 is used as a global mobility management protocol. This 131 interaction is very similar to the HMIPv6-MIPv6 interaction; 132 Mobile IPv6 is used to manage mobility among different access 133 networks, while the mobility within the access network is handled 134 by Proxy Mobile IPv6. The address managed by PMIPv6 (i.e. the MN- 135 HoA) is registered as Care-of Address by the MN at the HA. This 136 means that the HA has a binding cache entry for MIPv6-HoA that 137 points to the MN-HoA. 139 The following figure illustrates this scenario. 141 +----+ 142 | HA | MIPv6-HoA -> MN-HoA 143 +----+ 144 /\ 145 / \ 146 +-------------/----\--------------+ 147 ( / \ ) Global Mobile IPv6 148 ( / \ ) Domain 149 +----------/----------\-----------+ 150 / \ 151 +----+ +----+ 152 MN-HoA -> MAG1 |LMA1| |LMA2| 153 +----+ +----+ 154 //\\ \\ 155 +----//--\\---+ +-----\\------+ 156 ( // \\ ) ( \\ ) Local Mobility Network 157 ( // \\ ) ( \\ ) PMIPv6 domain 158 +-//--------\\+ +--------\\---+ 159 // \\ \\ 160 // \\ \\ 161 // \\ \\ 162 +----+ +----+ +----+ 163 |MAG1| |MAG2| |MAG3| 164 +----+ +----+ +----+ 165 | | | 166 [MN] 168 Figure 1 - Scenario A 170 o Scenario B - in this scenario some mobile nodes use Mobile IPv6 to 171 manage their movements while others rely on a network-based 172 mobility solution provided by the network as they don't support 173 Mobile IPv6. There may be a common mobility anchor that acts as 174 Mobile IPv6 Home Agent and Proxy Mobile IPv6 LMA, depending on the 175 type of the node as depicted in the figure. However, the LMA and 176 HA can be also separated and this has no impacts to the mobility 177 of the nodes. 179 +--------+ 180 | HA/LMA | 181 +--------+ 183 +------+ +------+ 184 | MAG1 | | MAG2 | 185 +------+ +------+ 187 +-----------+ 188 | IPv6 host | -----------------> 189 +-----------+ movement 190 +----------+ 191 | MIPv6 MN | -----------------> 192 +----------+ movement 194 Figure 2 - Scenario B 196 o Scenario C - in this scenario the mobile node is moving across 197 different access networks, some of them supporting Proxy Mobile 198 IPv6 and some others not supporting it. Therefore the mobile node 199 is roaming from an access network where the mobility is managed 200 through a network-based solution to an access network where a 201 host-based management (i.e. Mobile IPv6) is needed. This 202 scenario may have different sub-scenarios depending on the 203 relations between the Mobile IPv6 home network and the Proxy 204 Mobile IPv6 domain. The following figure illustrates an example 205 of this scenario, where the MN is moving from an access network 206 where PMIPv6 is supported (i.e. MAG functionality is supported) 207 to a network where PMIPv6 is not supported (i.e. MAG 208 functionality is not supported by the AR). This implies that the 209 home link of the MN is actually a PMIPv6 domain. In this case the 210 MIPv6-HoA is equal to the MN-HoA (i.e. the address managed by 211 PMIPv6). 213 MIPv6-HoA == MN-HoA -> MAG1 214 +------+ 215 |HA/LMA|-----------------------+ 216 +------+ | 217 //\\ | 218 +-------//--\\--------+ | 219 ( // \\ PMIPv6 ) | 220 ( // \\ domain) +--------------+ 221 +----//--------\\-----+ ( Non-PMIPv6 ) 222 // \\ ( domain ) 223 // \\ +--------------+ 224 // \\ | 225 +----+ +----+ +----+ 226 |MAG1| |MAG2| | AR | 227 +----+ +----+ +----+ 228 | | | 229 [MN] 231 Figure 3 - Scenario C 233 In the above figure the non-PMIPv6 domain can actually be also a 234 different PMIPv6 domain that handles a different MN_HoA. The 235 following figure illustrates this sub-case: the MIPv6-HoA is equal 236 to the MN_HoA; however when the MN hands over to MAG3 it gets a 237 different IP address (managed by LMA2 using PMIPv6) and registers 238 it as a MIPv6 CoA. 240 MIPv6-HoA == MN-HoA -> MAG_1 241 +-------+ 242 |HA/LMA1|-----------------------+ 243 +-------+ | 244 //\\ +----+ 245 +-------//--\\--------+ |LMA2| 246 ( // \\ home ) +----+ 247 ( // \\ PMIPv6) +------||------+ 248 ( // \\domain) ( ||visited) 249 +---//----------\\----+ ( ||PMIPv6 ) 250 // \\ ( ||domain ) 251 // \\ +------||------+ 252 +----+ +----+ +----+ 253 |MAG1| |MAG2| |MAG3| 254 +----+ +----+ +----+ 255 | | | 256 [MN] 258 (a) 260 MIPv6-HoA -> MN_CoA 261 +-------+ 262 |HA/LMA1|-----------------------+ 263 +-------+ | 264 //\\ +----+ 265 +-------//--\\--------+ |LMA2| MN_CoA -> MAG3 266 ( // \\ home ) +----+ 267 ( // \\ PMIPv6) +------||------+ 268 ( // \\domain) ( ||visited) 269 +---//----------\\----+ ( ||PMIPv6 ) 270 // \\ ( ||domain ) 271 // \\ +------||------+ 272 +----+ +----+ +----+ 273 |MAG1| |MAG2| |MAG3| 274 +----+ +----+ +----+ 275 | | | 276 [MN] 278 (b) 280 Figure 4 - Scenario C with visited PMIPv6 domain 282 Note that some of the scenarios can be combined. For instance, 283 scenario B can be combined with scenario A or scenario C. 285 The following sections describe some possible issues for each 286 scenario. Respective recommendations are described in Section 4.3. 287 The specifications considered as a baseline for the analysis are the 288 following: [RFC3775], [RFC4877] and [RFC5213]. 290 3.1. Issues related to scenario A 292 This scenario is very similar to other hierarchical mobility schemes, 293 including a HMIPv6-MIPv6 scheme. This is the scenario referenced in 294 [RFC4830]. No issues have been identified in this scenario. Note 295 that a race condition where the MN registers the CoA at the HA before 296 the CoA is actually bound to the MAG at the LMA is not possible. The 297 reason is that per PMIPv6 specification the MAG does not forward any 298 packets sent by the MN until the PMIPv6 tunnel is up, regardless the 299 mechanism used for address allocation. 301 Section 4.1 describes one message flow in case PMIPv6 is used as a 302 local mobility protocol and MIPv6 is used as a global mobility 303 protocol. 305 3.2. Issues related to scenario B 307 In this scenario there are two types of nodes in the access network: 308 some nodes support Mobile IPv6 while some others do not. The 309 rationale behind such a scenario is that the nodes implementing 310 Mobile IPv6 manage their own mobility to achieve better performance, 311 e.g. for inter-technology handovers. Obviously, nodes that do not 312 implement MIPv6 must rely on the network to manage their mobility: 313 therefore Proxy MIPv6 is used for those nodes. 315 Based on the current PMIPv6 solution described in [RFC5213], in any 316 link of the PMIPv6 domain the MAG emulates the mobile node's home 317 link, advertising the home link prefix to the MN in a unicast Router 318 Advertisement message. This ensures that the IP address of the MN is 319 still considered valid by the MN itself. The home network prefix 320 (and any other information needed to emulate the home link) is 321 included in the mobile node's profile that is obtained by the MAG via 322 context transfer or via a policy store. 324 However, in case there are nodes that implement Mobile IPv6 and want 325 to use this protocol, the network must offer MIPv6 service to them. 326 In such case the MAG should not emulate the home link. Instead of 327 advertising the HNP, the MAG should advertise the topologically 328 correct local IP prefix, i.e. the prefix belonging to the MAG, so 329 that the MN detects an IP movement, configures a new CoA and sends a 330 MIPv6 Binding Update based on [RFC3775]. 332 3.3. Issues related to scenario C 334 This section highlights some considerations that are applicable to 335 scenario C where the LMA and HA are logically collocated and need to 336 be evaluated when selecting the technical approach to be chosen. 338 1. HoA management and lookup key in the binding cache 340 * In MIPv6 [RFC3775] the lookup key in the Binding Cache is the 341 Home Address of the MN. In particular, based on the base 342 specification [RFC3775], the MN does not include any 343 identifier, such as the MN-ID [RFC4283], in the Binding Update 344 message other than its Home Address. As described in 345 [RFC4877], the identifier of the MN is known by the Home Agent 346 after the IKEv2 exchange, but this is not used in the MIPv6 347 signaling, nor as a lookup key for the binding cache. On the 348 other hand, as specified in [RFC5213], a Proxy Binding Update 349 contains the Home Prefix of the MN, the MN-ID and does not 350 include the Home Address of the MN (since it may not be known 351 by the MAG and consequently by the HA/LMA). The lookup key in 352 the binding cache of the LMA is either the home prefix or the 353 MN-ID. This implies that lookup keys for MIPv6 and PMIPv6 354 registrations are different. Because of that, when the MN 355 moves from its home network (i.e. from the PMIPv6 domain) to 356 the foreign link, the Binding Update sent by the MN is not 357 identified by the HA as an update of the Proxy Binding Cache 358 Entry containing the home prefix of the MN, but a new binding 359 cache entry is created. Therefore PMIPv6 and MIPv6 will 360 always create two different binding cache entries in the HA/ 361 LMA which implies that the HA and LMA are logically separated. 362 How to handle the presence of the two binding cache entries 363 for the same MN is described in Section 4.3. 365 2. MIPv6 de-registration Binding Update deletes PMIPv6 binding cache 366 entry 368 * When the mobile node moves from a MIPv6 foreign network to the 369 PMIPv6 home domain, the MAG registers the mobile node at the 370 LMA by sending a Proxy Binding Update. Subsequently, the LMA 371 updates the mobile node's binding cache entry with the MAG 372 address and the MAG emulates the mobile node's home link. 373 Upon detection of the home link, the mobile node will send a 374 de-registration Binding Update to its home agent. It is 375 necessary to make sure that the de-registration of the MIPv6 376 BU does not change the PMIPv6 binding cache entry just created 377 by the MAG. 379 3. Race condition between Binding Update and Proxy Binding Update 380 messages (Sequence Numbers and Timestamps) 382 * MIPv6 and PMIPv6 use different mechanisms for handling re- 383 ordering of registration messages and they are sent by 384 different entities. In MIPv6, Binding Update messages that 385 are sent by the mobile node to the home agent are ordered by 386 the sequence numbers. The other side, in PMIP, Proxy Binding 387 Update messages that are sent by the MAG to the LMA are 388 ordered by a timestamp option. . 390 4. Use of wrong home agent or LMA after handover 392 * This issues can arise if multiple LMAs are deployed in the 393 PMIPv6 home domain. If the mobile node moves from a MIPv6 394 foreign network to the PMIPv6 home domain, the MAG must send 395 the Proxy Binding Update to the particular LMA that is co- 396 located with the home agent which maintains the active binding 397 cache entry of the mobile node. If a different LMA is 398 assigned to the MAG, the mobile node will not be on the home 399 link but will still have an active MIPv6 binding cache entry 400 and this may be not desirable in some deployments.. 402 * Similarly, if the mobile node moves from the PMIPv6 home 403 domain to a MIPv6 foreign network, the mobile node must send 404 the Binding Update to the particular home agent that is co- 405 located with the LMA which maintains the active proxy binding 406 cache entry of the mobile node. If the mobile node selects a 407 different home agent, packets addressed to the mobile node's 408 home address do not reach the mobile node. 410 5. Threat of compromised MAG 412 * In MIPv6 base specification [RFC3775] there is a strong 413 binding between the Home Address registered by the mobile node 414 and the Security Association used to modify the corresponding 415 binding cache entry. 417 * In PMIPv6 specification, the MAG sends proxy binding updates 418 on behalf of a mobile node to update the binding cache entry 419 that corresponds to the mobile node's home address. Since the 420 MAG sends the binding updates, PMIPv6 requires security 421 associations between each MAG and the LMA. 423 * As described in [RFC4832], in PMIPv6 the MAG compromise or 424 impersonation is an issue. RFC4832, section 2.2, describes 425 how a compromised MAG can harm the functionality of LMA, e.g. 426 manipulating LMA's routing table (or binging cache). 428 * In this mixed scenario, both host-based and network-based 429 security associations are used to update the same binding 430 cache entry at the HA/LMA (but see the first bullet of this 431 list, as the entry may not be the same). Based on this 432 consideration, the threat described in [RFC4832] is worse as 433 it affects also hosts that are using the LMA/HA as MIPv6 HA 434 and are not using PMIPv6 436 4. Analysis of possible solutions 438 4.1. Solutions related to scenario A 440 As mentioned in Section 3.1, there are no significant issues in this 441 scenario. 443 Figures 5 and 6 show a scenario where a mobile node is moving from 444 one PMIPv6 domain to another, based on the scenario of Figure 1. In 445 Figure 5, the mobile node moves from an old MAG to MAG2 in the same 446 PMIPv6 domain: this movement triggers a PBU to LMA1 and the updating 447 of the binding cache at the LMA1; there is no MIPv6 signaling as the 448 CoA_1 registered at the HA is the Home Address for the PMIPv6 449 session. In Figure 6, the mobile node moves from MAG2 in the LMA1 450 PMIPv6 domain to MAG3 in a different PMIPv6 domain: this triggers the 451 PMIPv6 signaling and the creation of a binding at the LMA2. On the 452 other hand, the local address of the mobile node is changed, as the 453 LMA hss changed, and therefore the mobile node sends a MIPv6 Binding 454 Update to the HA with the new CoA_2. 456 +----+ +------+ +------+ +----+ 457 | MN | | MAG2 | | LMA1 | | HA | 458 +----+ +------+ +------+ +----+ 459 | | | | 460 | | | +-----------------+ 461 | | | | HoA -> CoA_1 | 462 | | | | binding present | 463 | | | +-----------------+ 464 | | | | 465 | CoA conf/confirm | PBU(CoA_1,MAG_2) | | 466 | <--------------->| ----------------->| | 467 | | +-----------------+| 468 | | | CoA_1 -> MAG_2 || 469 | | | binding updated || 470 | | +-----------------+| 471 | | PBA | | 472 | | <----------------| | 473 | | | | 475 Figure 5 - Local Mobility Message Flow 477 +----+ +------+ +------+ +----+ 478 | MN | | MAG3 | | LMA2 | | HA | 479 +----+ +------+ +------+ +----+ 481 | CoA config | PBU(CoA_2,MAG_3) | | 482 |<---------------->|------------------->| | 483 | | +-----------------+ | 484 | | | CoA_2 -> MAG_3 | | 485 | | | binding created | | 486 | | +-----------------+ | 487 | | PBA | | 488 | |<-------------------| | 489 | | | | 490 | | BU (HoA, CoA_2) | | 491 |---------------------------------------------------->| 492 | | | | 493 | | | +-----------------+ 494 | | | | HoA -> CoA_2 | 495 | | | | binding updated | 496 | | | +-----------------+ 497 | | BA | | 498 |<----------------------------------------------------| 500 Figure 6 - Global Mobility Message Flow 502 4.2. Solutions related to scenario B 504 The solution for this scenario may depend on the access network being 505 able to determine that a particular mobile node wants to use Mobile 506 IPv6. This requires a solution at the system level for the access 507 network and is out of scope of this document. Solutions that do not 508 depend on the access network are out of the scope of this document. 510 4.3. Solutions related to scenario C 512 As described in Section 3.3, in this scenario the mobile node relies 513 on Proxy Mobile IPv6 as long as it is in the Proxy Mobile IPv6 514 domain. The mobile node then uses Mobile IPv6 whenever it moves out 515 of the PMIPv6 domain which basically implies that the MIPv6 home link 516 is a PMIPv6 domain. 518 Analyzing the issues described in Section 3.3, it is clear that most 519 of them are applicable only to the case where there is a common 520 binding cache entry for the PMIPv6 registration and the MIPv6 521 registration. The issue 1 on how the two protocols identify the 522 binding cache entry is valid only in case we assume that a PMIPv6 523 message has any value for a MIPv6 BCE. Also the issues 2 and 3 are 524 not applicable in case different logical BCEs are used by the LMA and 525 the HA. For this reason, it is recommended that when the MIPv6 home 526 link is implemented as a PMIPv6 domain, the HA/LMA implementation 527 treats the two protocol as independent. 529 More in details the following principles should be followed by the 530 HA/LMA implementation: 532 o PMIPv6 signaling does not overwrite any MIPv6 BCE. In particular, 533 when a PMIPv6 binding cache entry is created for a mobile node 534 which has previously created a MIPv6 BCE, the MIPv6 binding cache 535 entry of the MN is not overwritten and a new PMIPv6 binding cache 536 entry is created. 538 o The downlink packets in the case where both the MIPv6 binding 539 cache entry and PMIPv6 binding cache entry exist are processed as 540 follows: 542 o 544 1. The MIPv6 binding cache entry is processed first. If the 545 destination address of the received downlink packet matches 546 the the binding cache entry of the HA, the packet is forwarded 547 by encapsulating it with the care-of-address contained in the 548 BCE. 550 2. If the destination address does not match the MIPv6 BCE, the 551 binding cache entry created by PMIPv6 is applied and the 552 packet are encapsualted to the registered MAG. 554 The following subsections provide a description of the procedures 555 which will be followed by the mobile node and HA/LMA based on the 556 above principles. The analysis is performed in two different 557 subsections, depending if the mobile node moves from a PMIPv6 domain 558 to a non-PMIPv6 domain or vice versa. 560 4.3.1. Mobility from a PMIPv6 domain to a non-PMIPv6 domain 562 Let's assume the mobile node is attached to a PMIPv6 domain and there 563 is a valid Proxy Binding Cache entry at the LMA. Then the mobile 564 node moves to a different access network and starts using MIPv6 (e.g. 565 because PMIPv6 is not supported). The mobile node needs to bootstrap 566 MIPv6 parameters and send a MIPv6 Binding Update in order to have 567 service continuity. Therefore the following steps must be performed 568 by the UE: 570 o HA/LMA address discovery: the mobile node needs to discover the IP 571 address of the LMA which has a valid binding cache entry for its 572 home network prefix. This is described in Section 3.3 as issue 4. 574 o Security Association establishment: the mobile node needs to 575 establish an IPsec Security Association with the HA/LMA as 576 described in [RFC4877] 578 o HoA or home network prefix assignment: as part of the MIPv6 579 bootstrapping procedure the HA assigns a MIPv6 HoA to the MN. 580 This address must be the same the mobile node was using in the 581 PMIPv6 domain. 583 Since all these steps must be performed by the mobile node before 584 sending the Binding Update, they have an impact on the handover 585 latency experienced by the MN. For this reason it is recommended 586 that the mobile node establishes the IPsec security association (and 587 consequently is provided by the HA/LMA with a MIPv6-HoA) when it is 588 still attached to the PMIPv6 domain. This implies that the mobile 589 node has Mobile IPv6 stack active while in the PMIPv6 domain, but as 590 long as it is attached to the same Proxy Mobile IPv6 domain, it will 591 appear to the mobile node as if it is attached to the home link. 593 In order to establish the security association with the HA/LMA, the 594 mobile node needs to discover the IP address of the LMA/HA while in 595 the PMIPv6 domain. This can be done either based on DNS or based on 596 DHCPv6, as described in [RFC5026] and [boot-integrated]. The network 597 should be configured so that the mobile node discovers or gets 598 assigned the same HA/LMA that was serving as the LMA in the PMIPv6 599 domain. Details of the exact procedure are out of scope of this 600 document. 602 When the mobile node establishes the security association, it 603 acquires a home address based on [RFC5026]. However, based on PMIPv6 604 operations, the LMA knows only the Home Network Prefix used by the 605 mobile node and does not know the MN-HoA.For this reason, the mobile 606 node must be configured to propose MN-HoA as the home address in the 607 IKEv2 INTERNAL_IP6_ADDRESS attribute during the IKEv2 exchange with 608 the HA/LMA. Alternatively the HA/LMA can be configured to provide 609 the entire Home Network Prefix via the MIP6_HOME_LINK attribute to 610 the mobile node as specified in [RFC5026]; based on this Home Network 611 Prefix the mobile node can configure a home address. Note that the 612 security association must be bound to the MN-HoA used in the PMIPv6 613 domain as per [RFC4877]. Note that the home network prefix is shared 614 between the LMA and HA and this implies that there is an interaction 615 between the LMA and the HA in order to assign a common home network 616 prefix when triggered by PMIPv6 and MIPv6 signaling 618 When the mobile node hands over to an access network which does not 619 support Proxy Mobile IPv6, it sends a Binding Update to the HA. The 620 mobile node may set the R bit defined in NEMO specification (implicit 621 mode) in order to indicate that the entire HNP is moved to the new 622 CoA. A MIPv6 binding cache entry is created irrespective of the 623 existing PMIPv6 BCE. Packets matching the MIPv6 binding cache entry 624 are sent to the CoA present in the MIPv6 BCE. The PMIPv6 binding 625 cache entry will expire in case the MAG does not send a refresh PBU. 627 4.3.2. Mobility from a non-PMIPv6 domain to a PMIPv6 domain 629 In this section it is assumed that the mobile node is in a non-PMIPv6 630 access network and it has bootstrapped MIPv6 operations based on 631 [RFC5026]; therefore there is valid binding cache for its MIPv6-HoA 632 (or HNP in case of NEMO) at the HA. Then the mobile node moves to a 633 PMIPv6 domain which is configured to be the home link for the MIPv6- 634 HoA the mobile node has been assigned. 636 In order to provide session continuity, the MAG needs to send a PBU 637 to the HA/LMA that was serving the MN. The MAG needs to discover the 638 HA/LMA; however the current version of [RFC5213] assumes that the LMA 639 is assigned to the MAG or discovered by the MAG when the mobile node 640 attaches to the MAG. the exact mechanism is not specified in 641 [RFC5213]. A detailed description of the necessary procedure is out 642 of the scope of this document. Note that the MAG may also rely on 643 static configuration or lower layer information provided by the 644 mobile node in order to select the correct HA/LMA. 646 The PBU sent by the MAG creates a PMIPv6 binding cache entry for the 647 mobile node which is independent of the MIPv6 BCE. Traffic destined 648 to the MIPv6-HoA (or to the HNP in case the mobile node had set the 649 flag R in the last BU) is still forwarded to the CoA present in the 650 MIPv6 BCE. When the mobile node wants to use the HoA directly from 651 the home link, it sends a de-registration message and at that point 652 only the PMIPv6 binding cache entry is present. 654 5. Security Considerations 656 Scenarios A and B described in Section 3 do not introduce any 657 security considerations in addition to those described in [pmipv6- 658 draft] or [RFC3775]. 660 This document requires that the a home agent that also implements the 661 PMIPv6 LMA functionality should allow both the mobile node and the 662 authorized MAGs to modify the binding cache entries for the mobile 663 node. Note that the compromised MAG threat described in [RFC4832] 664 applies also here. 666 6. Additional Authors 668 Chowdhury, Kuntal - kchowdhury@starentnetworks.com 670 Hesham Soliman - Hesham@elevatemobile.com 672 Vijay Devarapalli - vijay.devarapalli@azairenet.com 674 Sri Gundavelli - sgundave@cisco.com 676 Kilian Weniger - Kilian.Weniger@googlemail.com 678 Genadi Velev - Genadi.Velev@eu.panasonic.com 680 Ahmad Muhanna - amuhanna@nortel.com 682 George Tsirtsis - tsirtsis@googlemail.com 684 Suresh Krishnan - suresh.krishnan@ericsson.com 686 7. Acknowledgements 688 This document is a merge of four different Internet Drafts: 689 draft-weniger-netlmm-pmipv6-mipv6-issues-00, 690 draft-devarapalli-netlmm-pmipv6-mipv6-01, 691 draft-giaretta-netlmm-mip-interactions-00. Thanks to the authors and 692 editors of those drafts. 694 The authors would also like to thank Jonne Soininen and Vidya 695 Narayanan, NETLMM WG chairs, for their support. 697 8. References 699 8.1. Normative References 701 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 702 Requirement Levels", BCP 14, RFC 2119, March 1997. 704 [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support 705 in IPv6", RFC 3775, June 2004. 707 [RFC4832] Vogt, C. and J. Kempf, "Security Threats to Network-Based 708 Localized Mobility Management (NETLMM)", April 2007. 710 [RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with 711 IKEv2 and the Revised IPsec Architecture", 2005. 713 [RFC5026] Giaretta, G., Kempf, J., and V. Devarapalli, "Mobile IPv6 714 Bootstrapping in Split Scenario", RFC 5026, October 2007. 716 [RFC5213] Gundavelli, S., "Proxy Mobile IPv6", August 2008. 718 [boot-integrated] 719 Chowdhury, K., Ed., "MIP6-bootstrapping for the Integrated 720 Scenario", 2007. 722 8.2. Informative References 724 [RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology", 725 RFC 3753, June 2004. 727 [RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K. 728 Chowdhury, "Mobile Node Identifier Option for Mobile IPv6 729 (MIPv6)", RFC 4283, November 2005. 731 [RFC4831] Kempf, J., "Goals for Network-Based Localized Mobility 732 Management (NETLMM)", RFC 4831, April 2007. 734 Author's Address 736 Gerardo Giaretta (editor) 737 Qualcomm 739 Email: gerardog@qualcomm.com 741 Full Copyright Statement 743 Copyright (c) 2009 IETF Trust and the persons identified as the 744 document authors. All rights reserved. 746 This document is subject to BCP 78 and the IETF Trust's Legal 747 Provisions Relating to IETF Documents in effect on the date of 748 publication of this document (http://trustee.ietf.org/license-info). 749 Please review these documents carefully, as they describe your 750 rights and restrictions with respect to this document.