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(See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (July 14, 2009) is 5393 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 3775 (Obsoleted by RFC 6275) ** Downref: Normative reference to an Experimental RFC: RFC 4988 == Outdated reference: A later version (-18) exists of draft-ietf-netlmm-pmip6-ipv4-support-13 Summary: 4 errors (**), 0 flaws (~~), 2 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group H. Yokota 3 Internet-Draft KDDI Lab 4 Intended status: Standards Track K. Chowdhury 5 Expires: January 15, 2010 R. Koodli 6 Starent Networks 7 B. Patil 8 Nokia 9 F. Xia 10 Huawei USA 11 July 14, 2009 13 Fast Handovers for Proxy Mobile IPv6 14 draft-ietf-mipshop-pfmipv6-07.txt 16 Status of this Memo 18 This Internet-Draft is submitted to IETF in full conformance with the 19 provisions of BCP 78 and BCP 79. 21 Internet-Drafts are working documents of the Internet Engineering 22 Task Force (IETF), its areas, and its working groups. Note that 23 other groups may also distribute working documents as Internet- 24 Drafts. 26 Internet-Drafts are draft documents valid for a maximum of six months 27 and may be updated, replaced, or obsoleted by other documents at any 28 time. It is inappropriate to use Internet-Drafts as reference 29 material or to cite them other than as "work in progress." 31 The list of current Internet-Drafts can be accessed at 32 http://www.ietf.org/ietf/1id-abstracts.txt. 34 The list of Internet-Draft Shadow Directories can be accessed at 35 http://www.ietf.org/shadow.html. 37 This Internet-Draft will expire on January 15, 2010. 39 Copyright Notice 41 Copyright (c) 2009 IETF Trust and the persons identified as the 42 document authors. All rights reserved. 44 This document is subject to BCP 78 and the IETF Trust's Legal 45 Provisions Relating to IETF Documents in effect on the date of 46 publication of this document (http://trustee.ietf.org/license-info). 47 Please review these documents carefully, as they describe your rights 48 and restrictions with respect to this document. 50 Abstract 52 Mobile IPv6 (MIPv6) [RFC3775] provides a mobile node with IP mobility 53 when it performs a handover from one access router to another and 54 fast handovers for Mobile IPv6 (FMIPv6) [RFC5268bis] are specified to 55 enhance the handover performance in terms of latency and packet loss. 56 While MIPv6 (and FMIPv6 as well) requires the participation of the 57 mobile node in the mobility-related signaling, Proxy Mobile IPv6 58 (PMIPv6) [RFC5213] provides IP mobility to mobile nodes that either 59 have or do not have MIPv6 functionality without such involvement. 60 Nevertheless, the basic performance of PMIPv6 in terms of handover 61 latency and packet loss is considered not any different from that of 62 MIPv6. When the fast handover is considered in such an environment, 63 several modifications are needed to FMIPv6 to adapt to the network- 64 based mobility management. This document specifies the usage of Fast 65 Mobile IPv6 (FMIPv6) when Proxy Mobile IPv6 is used as the mobility 66 management protocol. Necessary extensions are specified for FMIPv6 67 to support the scenario when the mobile node does not have IP 68 mobility functionality and hence is not involved with either MIPv6 or 69 FMIPv6 operations. 71 Table of Contents 73 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 4 74 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 75 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 76 4. Proxy-based FMIPv6 Protocol Overview . . . . . . . . . . . . . 7 77 4.1. Protocol Operation . . . . . . . . . . . . . . . . . . . . 8 78 4.2. Inter-AR Tunneling Operation . . . . . . . . . . . . . . . 14 79 4.3. IPv4 Support Considerations . . . . . . . . . . . . . . . 15 80 5. PMIPv6-related Fast Handover Issues . . . . . . . . . . . . . 16 81 6. Message Formats . . . . . . . . . . . . . . . . . . . . . . . 17 82 6.1. Mobility Header . . . . . . . . . . . . . . . . . . . . . 17 83 6.1.1. Handover Initiate (HI) . . . . . . . . . . . . . . . . 17 84 6.1.2. Handover Acknowledge (HAck) . . . . . . . . . . . . . 18 85 6.2. Mobility Options . . . . . . . . . . . . . . . . . . . . . 20 86 6.2.1. Context Request Option . . . . . . . . . . . . . . . . 20 87 6.2.2. Local Mobility Anchor Address (LMAA) Option . . . . . 22 88 6.2.3. Mobile Node Interface Identifier (MN IID) Option . . . 22 89 6.2.4. Home Network Prefix Option . . . . . . . . . . . . . . 23 90 6.2.5. Link-local Address Option . . . . . . . . . . . . . . 23 91 6.2.6. GRE Key Option . . . . . . . . . . . . . . . . . . . . 23 92 6.2.7. IPv4 Address Option . . . . . . . . . . . . . . . . . 23 93 6.2.8. Vendor-Specific Mobility Option . . . . . . . . . . . 24 94 7. Security Considerations . . . . . . . . . . . . . . . . . . . 25 95 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26 96 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27 97 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 28 98 10.1. Normative References . . . . . . . . . . . . . . . . . . . 28 99 10.2. Informative References . . . . . . . . . . . . . . . . . . 28 100 Appendix A. Applicable Use Cases . . . . . . . . . . . . . . . . 29 101 A.1. PMIPv6 Handoff Indication . . . . . . . . . . . . . . . . 29 102 A.2. Local Routing . . . . . . . . . . . . . . . . . . . . . . 29 103 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 31 104 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 35 106 1. Requirements notation 108 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 109 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 110 document are to be interpreted as described in [RFC2119]. 112 2. Introduction 114 Proxy Mobile IPv6 [RFC5213] provides IP mobility to a mobile node 115 that does not possess Mobile IPv6 [RFC3775] mobile node 116 functionality. A proxy agent in the network performs the mobility 117 management signaling on behalf of the mobile node. This model 118 transparently provides mobility for mobile nodes within a PMIPv6 119 domain. Nevertheless, the basic performance of PMIPv6 in terms of 120 handover latency and packet loss is considered not any different from 121 that of Mobile IPv6. 123 Fast Handovers for Mobile IPv6 (FMIPv6) [RFC5268bis] describes the 124 protocol to reduce the handover latency for Mobile IPv6 by allowing a 125 mobile node to send packets as soon as it detects a new subnet link 126 and by delivering packets to the mobile node as soon as its 127 attachment is detected by the new access router. This document 128 describes necessary extensions to FMIPv6 to minimize handover delay 129 and packet loss as well as to transfer network-resident context for a 130 PMIPv6 handover. 132 3. Terminology 134 This document reuses terminology from [RFC5213], [RFC5268bis] and 135 [RFC3775]. The following terms and abbreviations are additionally 136 used in this document. 138 Access Network (AN): 139 A network composed of link-layer access devices such as access 140 points or base stations providing access to the Access Router 141 (AR) connected to it. 143 Previous Access Network (P-AN): 144 The access network to which the MN is attached before handover. 146 New Access Network (N-AN): 147 The access network to which the MN is attached after handover. 149 Previous Mobile Access Gateway (PMAG): 150 The MAG that manages mobility related signaling for the MN 151 before handover. In this document, the MAG and the Access 152 Router are collocated. 154 New Mobile Access Gateway (NMAG): 155 The MAG that manages mobility related signaling for the MN after 156 handover. In this document, the MAG and the Access Router (AR) 157 are collocated. 159 HO-Initiate: 160 A generic signaling message, sent from the P-AN to the PMAG that 161 indicates a MN handover. While this signaling is dependent on 162 the access technology, it is assumed that HO-Initiate can carry 163 the information to identify the MN and to assist the PMAG 164 resolve the NMAG and the new access point or the base station to 165 which the MN is moving to. The details of this message are 166 outside the scope of this document. 168 4. Proxy-based FMIPv6 Protocol Overview 170 In order to improve the performance during handover (when operations 171 such as attachment to a new network and signaling between mobility 172 agents are involved), the PFMIPv6 protocol in this document specifies 173 a bi-directional tunnel between the Previous MAG (PMAG) and the New 174 MAG (NMAG) to tunnel packets meant for the mobile node. In order to 175 enable the NMAG to send the Proxy Binding Update (PBU), the Handover 176 Initiate (HI) and Handover Acknowledge (HAck) messages in 177 [RFC5268bis] are used for context transfer, in which parameters such 178 as MN's NAI, Home Network Prefix (HNP), IPv4 Home Address, are 179 transferred from the PMAG. A new flag 'P' is defined for the HI and 180 HAck messages to distinguish from those in [RFC5268bis] and thus MUST 181 be set in the entire document. 183 In this document, the Previous Access Router (PAR) and New Access 184 Router (NAR) are interchangeable with the PMAG and NMAG, 185 respectively. The reference network is illustrated in Figure 1. 187 Since a MN is not directly involved with IP mobility protocol 188 operations, it follows that the MN is not directly involved with fast 189 handover procedures either. Hence, the messages involving the MN in 190 [RFC5268bis] are not used when PMIPv6 is in use. More specifically, 191 the Router Solicitation for Proxy Advertisement (RtSolPr), the Proxy 192 Router Advertisement (PrRtAdv), Fast Binding Update (FBU), Fast 193 Binding Acknowledgment (FBack) and the Unsolicited Neighbor 194 Advertisement (UNA) messages are not applicable in the PMIPv6 195 context. 197 +----------+ 198 | LMA | 199 | | 200 +----------+ 201 / \ 202 / \ 203 / \ 204 +........../..+ +..\..........+ 205 . +-------+-+ .______. +-+-------+ . 206 . | PAR |()_______)| NAR | . 207 . | (PMAG) | . . | (NMAG) | . 208 . +----+----+ . . +----+----+ . 209 . | . . | . 210 . ___|___ . . ___|___ . 211 . / \ . . / \ . 212 . ( P-AN ) . . ( N-AN ) . 213 . \_______/ . . \_______/ . 214 . | . . | . 215 . +----+ . . +----+ . 216 . | MN | ----------> | MN | . 217 . +----+ . . +----+ . 218 +.............+ +.............+ 220 Figure 1: Reference network for fast handover 222 4.1. Protocol Operation 224 There are two modes of operation in FMIPv6 [RFC5268bis]. In the 225 predictive mode of fast handover, a bi-directional tunnel between the 226 PAR and NAR is established prior to the MN's attachment to the NAR. 227 In the reactive mode, this tunnel establishment takes place after the 228 MN attaches to the NAR. In order to alleviate the packet loss during 229 a MN's handover (especially when the MN is detached from both links), 230 the downlink packets for the MN need to be buffered either at the PAR 231 (PMAG) or NAR (NMAG), depending on when the packet forwarding is 232 performed. It is hence required that all MAGs have the capability 233 and enough resources to buffer packets for the MNs accommodated by 234 them. Note that the protocol operation specified in the document is 235 transparent to the LMA, hence there is no new functional requirement 236 or change on the LMA. 238 Since the MN is not involved in IP mobility signaling in PMIPv6, the 239 sequence of events illustrating the predictive fast handover are 240 shown in Figure 2. 242 PMAG NMAG 243 MN P-AN N-AN (PAR) (NAR) LMA 244 | | | | | | 245 | Report | | | | | 246 (a) |-(MN ID,-->| | | | | 247 | New AP ID)| | | | | 248 | | HO Initiate | | | 249 (b) | |--(MN ID, New AP ID)-->| | | 250 | | | | | | 251 | | | | HI | | 252 (c) | | | |-(MN ID, ->| | 253 | | | | MN IID, LMAA) | 254 | | | | | | 255 (d) | | | |<---HAck---| | 256 | | | | (MN ID) | | 257 | | | | | | 258 | | | |HI/HAck(optional) | 259 (e) | | | |<- - - - ->| | 260 | | | #=|<===================| 261 (f) | | | #====DL data=>| | 262 | | | | | | 263 (g) ~~~ | | | | | 264 ~~~ | | | | | 265 | MN-AN connection | AN-MAG connection | | 266 (h) |<---establishment---->|<----establishment----->| | 267 | | | (substitute for UNA) | | 268 | | | | | | 269 (i) |<==================DL data=====================| | 270 | | | | | | 271 (j) |===================UL data====================>|=# | 272 | | | #=|<============# | 273 | | | #=====================>| 274 / | | | | | | \ 275 |(k) | | | | |--PBU-->| | 276 | | | | | | | | 277 |(l) | | | | |<--PBA--| | 278 \ | | | | | | / 280 Figure 2: Predictive fast handover for PMIPv6 (PAR initiated) 282 The detailed descriptions are as follows: 284 (a) The MN detects that a handover is imminent and reports the 285 identifications of itself (MN ID) and the access point (New AP 286 ID) to which the MN is most likely to move. The MN ID could be 287 the NAI or a Link Layer Address (LLA), or any other suitable 288 identifier. This step is access technology specific. In some 289 cases, the P-AN will determine which AP ID the MN is moving to. 291 (b) The previous access network (P-AN), to which the MN is currently 292 attached, indicates the handover of the MN to the PAR (PMAG). 293 Detailed definition and specification of this message are 294 outside the scope of this document. 296 (c) The PAR sends the HI to the NAR. The HI message MUST have the P 297 flag set and include the MN ID, the MN-HNP, the MN-IID and the 298 address of the LMA that is currently serving the MN. 300 (d) The NAR sends the HAck back to the PAR with the P flag set. 302 (e) If it is preferred that the timing of buffering or forwarding 303 should be later than step (c), the NAR may optionally request 304 the PAR at a later and appropriate time to buffer or forward 305 packets by setting U flag [RFC5268bis] or F flag in the HI 306 message, respectively. 308 (f) If the F flag is set in the previous step, a bi-directional 309 tunnel is established between the PAR and NAR and packets 310 destined for the MN are forwarded from the PAR to the NAR over 311 this tunnel. After decapsulation, those packets may be buffered 312 at the NAR. If the connection between the N-AN and NAR has 313 already been established, those packets may be forwarded towards 314 the N-AN, which then becomes responsible for them (e.g., 315 buffering or delivering depending on the condition of the MN's 316 attachment); this is access technology specific. 318 (g) The MN undergoes handover to the New Access Network (N-AN). 320 (h) The MN establishes a physical link connection with the N-AN 321 (e.g., radio channel assignment), which in turn triggers the 322 establishment of a link-layer connection between the N-AN and 323 NAR if not yet established. An IP layer connection setup may be 324 performed at this time (e.g., PPP IPv6CP) or at a later time 325 (e.g., stateful or stateless auto address configuration). This 326 step can be a substitute for the UNA in [RFC5268bis], but since 327 they are all access technology specific, details are outside the 328 scope of this document. 330 (i) The NAR starts to forward packets destined for the MN via the 331 N-AN. 333 (j) The uplink packets from the MN are sent to the NAR via the N-AN 334 and the NAR forwards them to the PAR. The PAR then sends the 335 packets to the LMA that is currently serving the MN. 337 (k) The NAR (NMAG) sends the Proxy Binding Update (PBU) to the LMA, 338 whose address is provided in (c). Steps (k) and (l) are not 339 part of the fast handover procedure, but shown for reference. 341 (l) The LMA sends back the Proxy Binding Acknowledgment (PBA) to the 342 NAR (NMAG). From this time on, the packets to/from the MN go 343 through the NAR instead of the PAR. 345 According to Section 4 of [RFC5268bis], the PAR establishes a binding 346 between the PCoA and NCoA to forward packets for the MN to the NAR, 347 and the NAR creates a proxy NCE to receive those packets for the NCoA 348 before the MN arrives. In the case of PMIPv6, however, the only 349 address that is used by the MN is MN-HoA. Hence the PAR forwards 350 MN's packets to the NAR instead of the NCoA. FMIPv4 [RFC4988] 351 specifies forwarding when the MN uses HoA as its on-link address 352 rather than the care-of address. The usage in PMIPv6 is similar to 353 that in FMIPv4, where the address is used by the MN is based on Home 354 Network Prefix. Hence the PAR forwards MN's packets to the NAR 355 instead of the NCoA. The NAR then simply decapsulates those packets 356 and delivers them to the MN. Since the NAR obtains the LLA (MN IID) 357 and MN-HNP by the HI, it can create the NCE for the MN and deliver 358 packets to it even before the MN can perform Neighbor Discovery. For 359 the uplink packets from the MN after handover in (j), the NAR 360 forwards the packets to the PAR through the tunnel established in 361 step (f). The PAR then decapsulates and sends them to the LMA. 363 The timing of the context transfer and that of packet forwarding may 364 be different. Thus, a new flag 'F' and Option Code values for it in 365 the HI and HAck messages are defined to request forwarding. To 366 request buffering, 'U' flag has already been defined in [RFC5268bis]. 367 If the PAR receives the HI message with the F flag set, it starts 368 forwarding packets for the MN. The HI message with the U flag set 369 may be sent earlier if the timing of buffering is different from that 370 of forwarding. If packet forwarding is completed, the PAR MAY send 371 the HI message with the F flag set and the Option Code value being 2. 372 By this message, the ARs on both ends can tear down the forwarding 373 tunnel synchronously. 375 The IP addresses in the headers of those user packets are summarized 376 below: 378 In (f), 380 Inner source address: IP address of the CN 381 Inner destination address: HNP or IPv4-MN-HoA 383 Outer source address: IP address of the PAR (PMAG) 385 Outer destination address: IP address of the NAR (NMAG) 387 In (i), 389 Source address: IP address of the CN 391 Destination address: HNP or IPv4-MN-HoA 393 In (j), 395 - from the MN to the NMAG, 397 Source address: HNP or IPv4-MN-HoA 399 Destination address: IP address of the CN 401 - from the NMAG to the PMAG, 403 Inner source address: HNP or IPv4-MN-HoA 405 Inner destination address: IP address of the CN 407 Outer source address: IP address of the NAR (NMAG) 409 Outer destination address: IP address of the PAR (PMAG) 411 - from the PMAG to the LMA, 413 Inner source address: HNP or IPv4-MN-HoA 415 Inner destination address: IP address of the CN 417 Outer source address: IP address of the PAR (PMAG) 419 Outer destination address: IP address of the LMA 421 The encapsulation type for these user packets SHOULD follow that used 422 in the tunnel between the LMA and MAG (IPv6-in-IPv6 as specified in 423 [RFC2473], IPv6-in-IPv4, IPv6-in-IPv4-UDP, IPv6-in-IPv4-UDP-TLV as 424 specified in [IPv4PMIPv6], GRE as specified in [GREKEY] or any new 425 method defined in the future). 427 In the case of the reactive handover for PMIPv6, since the MN does 428 not send either the FBU or UNA, it would be more natural that the NAR 429 sends the HI to the PAR after the MN has moved to the new link. The 430 NAR then needs to obtain the information of the PAR beforehand. Such 431 information could be provided, for example, by the MN sending the 432 AP-ID on the old link and/or by the lower-layer procedures between 433 the P-AN and N-AN. The exact method is not specified in this 434 document. Figure 3 illustrates the reactive fast handover procedures 435 for PMIPv6, where the bi-directional tunnel establishment is 436 initiated by the NAR. 438 PMAG NMAG 439 MN P-AN N-AN (PAR) (NAR) LMA 440 | | | | | | 441 (a) ~~~ | | | | | 442 ~~~ | | | | | 443 | MN-AN connection | AN-MAG connection | | 444 (b) |<--establishment-->|<-------establishment------>| | 445 |(MN ID, Old AP ID) | (MN ID, Old AP ID) | | 446 | | |(substitute for UNA and FBU)| | 447 | | | | | | 448 | | | | HI | | 449 (c) | | | |<---(MN ID) ---| | 450 | | | | | | 451 | | | | HAck | | 452 (d) | | | |---(MN ID, --->| | 453 | | | | MN IID, LMAA) | | 454 | | | | | | 455 (e) | | | #=|<=======================| 456 | | | #================>|=# | 457 |<====================DL data======================# | 458 | | | | | | 459 (f) |=====================UL data===================>|=# | 460 | | | #=|<================# | 461 | | | #=========================>| 462 | | | | | | 463 / | | | | | | \ 464 |(g) | | | | |--PBU-->| | 465 | | | | | | | | 466 |(h) | | | | |<--PBA--| | 467 \ | | | | | | / 469 Figure 3: Reactive fast handover for PMIPv6 (NAR initiated) 471 The detailed descriptions are as follows: 473 (a) The MN undergoes handover from the P-AN to the N-AN. The AP-ID 474 on the old link may be provided by the MN to help identify the 475 PMAG on the new link. 477 (b) The MN establishes a connection (e.g., radio channel) with the 478 N-AN, which triggers the establishment of the connection between 479 the N-AN and NAR. The MN ID is transferred to the NAR for the 480 subsequent procedures. The AP-ID on the old link may also be 481 provided by the MN to help identify the PMAG on the new link. 482 This can be regarded as a substitute for the UNA and FBU. 484 (c) The NAR sends the HI to the PAR. The HI message MUST have the P 485 flag set and include the MN ID. The Context Request Option MAY 486 be included to request additional context information on the MN 487 to the PAR. 489 (d) The PAR sends the HAck back to the NAR with the P flag set. The 490 HAck message MUST include the HNP and/or IPv4-MN-HoA that is 491 corresponding to the MN ID in the HI message and SHOULD include 492 the MN-IID and the LMA address that is currently serving the MN. 493 The context information requested by the NAR MUST be included. 494 If the requested context is not available for some reason, the 495 PAR MUST return the HAck with the Code value 131. If the F flag 496 is set in the HI at step (c) and forwarding is nevertheless not 497 executable for some reason, the PAR MUST return the HAck with 498 the Code value 132. 500 (e) If the F flag in the HI is set at step (c), a bi-directional 501 tunnel is established between the PAR and NAR and packets 502 destined for the MN are forwarded from the PAR to the NAR over 503 this tunnel. After decapsulation, those packets are delivered 504 to the MN via the N-AN. 506 (f) The uplink packets from the MN are sent to the NAR via the N-AN 507 and the NAR forwards them to the PAR. The PAR then sends the 508 packets to the LMA that is currently serving the MN. 510 Steps (g)-(h) are the same as (k)-(l) in the predictive fast handover 511 procedures. 513 In step (c), The IP address of the PAR needs to be resolved by the 514 NAR to send the HI to the PAR. This information may come from the 515 N-AN or some database that the NAR can access. 517 4.2. Inter-AR Tunneling Operation 519 When the PMAG (PAR) or NMAG (NAR), depending on the fast handover 520 mode, receives the HI message with the F flag set, it prepares to 521 send/receive the MN's packets to/from the other MAG and returns the 522 HAck message with the same sequence number. The necessary 523 information MUST be transferred in the HI message to distinguish MN's 524 packets for forwarding in advance or at this time. Such information 525 includes the HoA of the MN and/or GRE key(s). For the downlink 526 packets, the PMAG redirects MN's packets from the LMA towards the 527 NMAG and if the MN is ready to receive those packets or the N-AN can 528 handle them regardless of the state of the MN, the NAR should 529 immediately send them towards the N-AN; otherwise it should buffer 530 them until the MN is ready. For the uplink packets, the NMAG SHOULD 531 reverse-tunnel them from the MN towards the PMAG and the PMAG sends 532 them to the LMA. 534 When the PMAG or NMAG receives the HI message with the U flag set, it 535 prepares to buffer the MN's packets and returns the HAck message with 536 the same sequence number. It MUST be followed by another HI message 537 with the F flag set at an appropriate time to forward the buffered 538 packets. 540 If the MAG that received the HI message encounters an erroneous 541 situation (e.g., insufficient buffer space), it SHOULD immediately 542 send the HAck message with the cause of the error and cancel all 543 tunneling operation. 545 4.3. IPv4 Support Considerations 547 The motivation and usage scenarios of IPv4 protocol support by PMIPv6 548 are described in [IPv4PMIPv6]. The scope of IPv4 support covers the 549 following two features: 551 o IPv4 Home Address Mobility Support, and 553 o IPv4 Transport Support. 555 As for IPv4 Home Address Mobility Support, the MN acquires IPv4 Home 556 Address (IPv4-MN-HoA) and in the case of handover, the PMAG needs to 557 transfer IPv4-MN-HoA to the NMAG, which is the inner destination 558 address of the packets forwarded on the downlink. For this purpose, 559 a new option called IPv4 Address Option is defined in this document. 560 In order to provide IPv4 Transport Support, the NMAG needs to know 561 the IPv4 address of the LMA (IPv4-LMAA) to send PMIPv6 signaling 562 messages to the LMA in the IPv4 transport network. In this case, a 563 new option called LMA Address (LMAA) option is used so as to convey 564 IPv4-LMAA from the PMAG to NMAG. The supported encapsulation type 565 follows Section 6.10.2 in [RFC5213], that is, IPv4, IPv4-UDP and 566 IPv4-UDP-TLV. 568 5. PMIPv6-related Fast Handover Issues 570 The protocol specified in this document enables the NMAG to obtain 571 parameters which would otherwise be available only by communicating 572 with the LMA. For instance, the HNP and/or IPv4-MN-HoA of a MN are 573 made available to the NMAG through context transfer. This allows the 574 NMAG to perform some procedures that may be beneficial. For 575 instance, the NMAG could send a Router Advertisement (RA) with the 576 HNP option to the MN as soon as its link attachment is detected 577 (e.g., via receipt of a Router Solicitation message). Such an RA is 578 recommended, for example, in scenarios where the MN uses a new radio 579 interface while attaching to the NMAG; since the MN does not have 580 information regarding the new interface, it will not be able to 581 immediately send packets without first receiving an RA with HNP. 582 Especially, in the reactive fast handover, the NMAG gets to know the 583 HNP assigned to the MN on the previous link at step (d) in Figure 3. 584 In order to reduce the communication disruption time, the NMAG SHOULD 585 expect the MN to keep using the same HNP and to send uplink packets 586 before that step upon the MN's request. However, if the HAck from 587 the PMAG returns a different HNP or the subsequent PMIPv6 binding 588 registration for the HNP fails for some reason, then the NMAG MUST 589 withdraw the advertised HNP by sending another RA with zero prefix 590 lifetime for the HNP in question. This operation is the same as 591 described in Section 6.12 of [RFC5213]. 593 The protocol specified in this document is applicable regardless of 594 whether link-layer addresses are used between a MN and its access 595 router. A MN should be able to continue sending packets on the 596 uplink even when it changes link. When link-layer addresses are 597 used, the MN performs Neighbor Unreachability Detection (NUD) 598 [RFC4861], after attaching to a new link, probing the reachability of 599 its default router. If the new router's interface is configured to 600 respond to queries sent to link-layer addresses than its own (e.g., 601 set to promiscuous mode), then it can respond to the NUD probe, 602 providing its link-layer address in the solicited Neighbor 603 Advertisement. Implementations should allow the MN to continue to 604 send uplink packets while it is performing NUD. 606 6. Message Formats 608 This document defines new Mobility Header messages for the extended 609 HI and Hack and new mobility options for conveying context 610 information. 612 6.1. Mobility Header 614 6.1.1. Handover Initiate (HI) 616 This section defines extensions to the HI message in [RFC5268bis]. 617 The format of the Message Data field in the Mobility Header is as 618 follows: 620 0 1 2 3 621 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 1 622 +-------------------------------+ 623 | Sequence # | 624 +-+-+-+-+-------+---------------+-------------------------------+ 625 |S|U|P|F|Resv'd | Code | | 626 +-+-+-+-+-------+---------------+ | 627 | | 628 . . 629 . Mobility options . 630 . . 631 | | 632 +---------------------------------------------------------------+ 634 IP Fields: 636 Source Address 638 The IP address of PMAG or NMAG 640 Destination Address 642 The IP address of the peer MAG 644 Message Data: 646 Sequence # Same as [RFC5268bis]. 648 S flag Defined in [RFC5268bis] and MUST be set to zero in this 649 specification. 651 U flag Buffer flag. Same as [RFC5268bis]. 653 P flag Proxy flag. Used to distinguish the message from that 654 defined in [RFC5268bis] and to indicate that it follows 655 the specification in this document. 657 F flag Forwarding flag. Used to request to forward the packets 658 for the MN. 660 Reserved Same as [RFC5268bis]. 662 Code [RFC5268bis] defines this field and its values 0 and 1. 663 In this specification, with the P flag set, this field 664 can be set to zero by default or the following values: 666 2: Indicate the completion of forwarding 668 3: All available context transferred 670 Code value 3 is set when the transfer of all necessary 671 context information is completed with this message. This 672 Code value is used in both cases where the context 673 information is fragmented into several pieces and the 674 last fragment is contained in this message and where the 675 whole information is transferred in one piece. 677 Mobility options: 679 This field contains one or more mobility options, whose encoding and 680 formats are defined in [RFC3775]. At least one mobility option MUST 681 uniquely identify the target MN (e.g., the Mobile Node Identifier 682 Option defined in RFC4283) and the transferred context MUST be for 683 one MN per message. In addition, the NAR can request necessary 684 mobility options by the Context Request Option defined in this 685 document. 687 Context Request Option 689 This option MAY be present to request context information 690 typically by the NAR to the PAR in the NAR-initiated fast 691 handover. 693 6.1.2. Handover Acknowledge (HAck) 695 This section defines extensions to the HAck message in[RFC5268bis]. 696 The format of the Message Data field in the Mobility Header is as 697 follows: 699 0 1 2 3 700 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 1 701 +-------------------------------+ 702 | Sequence # | 703 +-+-+-+---------+---------------+-------------------------------+ 704 |U|P|F|Reserved | Code | | 705 +-+-+-+---------+---------------+ | 706 | | 707 . . 708 . Mobility options . 709 . . 710 | | 711 +---------------------------------------------------------------+ 713 IP Fields: 715 Source Address 717 Copied from the destination address of the 718 Handover Initiate message to which this message 719 is a response. 721 Destination Address 723 Copied from the source address of the Handover 724 Initiate message to which this message is a 725 response. 727 Message Data: 729 The usages of Sequence # and Reserved fields are exactly the same as 730 those in [RFC5268bis]. 732 U flag Same as defined in Section 6.1.1. 734 P flag Used to distinguish the message from that defined in 735 [RFC5268bis] and to indicate that it follows the 736 specification in this document. 738 F flag Same as defined in Section 6.1.1. 740 Code 741 Code values 0 through 4 and 128 through 130 are defined 742 in [RFC5268bis]. In this specification, the meaning of 743 Code value 0 is modified, 128 through 130 are reused, and 744 5, 6, 131 and 132 are newly defined. 746 0: Handover Accepted or Successful 748 5: Context Transfer Accepted or Successful 750 6: All available Context Transferred 752 128: Handover Not Accepted, reason unspecified 754 129: Administratively prohibited 756 130: Insufficient resources 758 131: Requested Context Not Available 760 132: Forwarding Not Available 762 Mobility options: 764 This field contains one or more mobility options, whose encoding and 765 formats are defined in [RFC3775]. The mobility option that uniquely 766 identifies the target MN MUST be copied from the corresponding HI 767 message and the transferred context MUST be for one MN per message. 769 Requested option(s) All the context information requested by the 770 Context Request Option in the HI message SHOULD be present 771 in the HAck message. The other cases are described below. 773 In the case of the PAR-initiated fast handover, when the PAR sends 774 the HI message to the NAR with the context information and the NAR 775 successfully receives it, the NAR returns the HAck message with Code 776 value 5. In the case of the NAR-initiated fast handover, when the 777 NAR sends the HI message to the PAR with or without Context Request 778 Option, the PAR returns the HAck message with the requested or 779 default context information (if any). If all available context 780 information is transferred, the PAR sets the Code value in the HAck 781 message to 6. If more context information is available, the PAR sets 782 the Code value in the HAck to 5 and the NAR MAY send new HI 783 message(s) to retrieve the rest of the available context information. 784 If none of the requested context information is available, the PAR 785 returns the HAck message with Code value 131 without any context 786 information. 788 6.2. Mobility Options 790 6.2.1. Context Request Option 792 This option is sent in the HI message to request context information 793 on the MN. If a default set of context information is defined and 794 always sufficient, this option is not mandatory. This option is more 795 useful to retrieve additional or dynamically selected context 796 information. 798 Context Request Option is typically used for the reactive (NAR- 799 initiated) fast handover mode to retrieve the context information 800 from the PAR. When this option is included in the HI message, all 801 the requested context information SHOULD be included in the HAck 802 message in the corresponding mobility option(s) (e.g., HNP, LMAA or 803 MN-IID mobility options). 805 0 1 2 3 806 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 1 807 +---------------+---------------+---------------+---------------+ 808 | Option-Type | Option-Length | Reserved | 809 +---------------+---------------+-------------------------------+ 810 | Req-type-1 | Req-length-1 | Req-type-2 | Req-length-2 | 811 +---------------------------------------------------------------+ 812 | ... | 814 Option-Type TBD1 816 Option-Length The length in octets of this option, not including the 817 Option Type and Option Length fields. 819 Reserved This field is unused. It MUST be initialized to zero 820 by the sender and MUST be ignored by the receiver. 822 Req-type-n The type value for the n'th requested option. 824 Req-length-n The length of the n'th requested option excluding the 825 Req-type-n and Req-length-n fields. 827 In the case where there are only Req-type-n and Req-length-n fields, 828 the value of the Req-length-n is set to zero. If additional 829 information besides the Req-type-n is necessary to uniquely specify 830 the requested context, such information follows after the 831 Req-length-n. For example, when the requested context is the Vendor- 832 Specific Option described in Section 6.2.8, the requested option 833 format looks as follows: 835 | ... | 836 +---------------+---------------+-------------------------------+ 837 | Req-type-N=19 | Req-length-N=5| Vendor-ID | 838 +-------------------------------+---------------+---------------+ 839 | Vendor-ID | Sub-Type | | 840 +-----------------------------------------------+ | 841 | ... | 843 The exact values in the Vendor-ID and Sub-Type are outside the scope 844 of this document. 846 6.2.2. Local Mobility Anchor Address (LMAA) Option 848 This option is used to transfer the Local Mobility Anchor IPv6 849 Address (LMAA) or its IPv4 Address (IPv4-LMAA), with which the MN is 850 currently registered. The detailed definition of the LMAA is 851 described in [RFC5213]. 853 0 1 2 3 854 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 1 855 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 856 | Option-Type | Option-Length | Option-Code | Reserved | 857 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 858 | Local Mobility Anchor Address ... | 860 Option-Type TBD2 862 Option-Length 18 or 6 864 Option-Code 866 0 Reserved 868 1 IPv6 address of the LMA (LMAA) 870 2 IPv4 address of the LMA (IPv4-LMAA) 872 Reserved This field is unused. It MUST be initialized to zero 873 by the sender and MUST be ignored by the receiver. 875 Local Mobility Anchor Address 876 If Option-Code is 1, the LMA IPv6 address (LMAA) is 877 inserted. If Option-Code is 2, the LMA IPv4 address 878 (IPv4-LMA) is inserted. 880 6.2.3. Mobile Node Interface Identifier (MN IID) Option 882 This option is used to transfer the interface identifier of the MN 883 that is used in the P-AN. 885 0 1 2 3 886 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 1 887 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 888 | Option-Type | Option-Length | Reserved | 889 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 890 | | 891 + Interface Identifier + 892 | | 893 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 895 Option-Type TBD3 897 Option-Length 10 899 Reserved This field is unused. It MUST be initialized to zero 900 by the sender and MUST be ignored by the receiver. 902 Interface Identifier 903 The Interface Identifier value of the MN that is used 904 in the P-AN. 906 6.2.4. Home Network Prefix Option 908 This option is used to transfer the home network prefix that is 909 assigned to the MN in the P-AN. The Home Network Prefix Option 910 defined in [RFC5213] is used for this. 912 6.2.5. Link-local Address Option 914 This option is used to transfer the link-local address of the PAR 915 (PMAG). The Link-local Address Option defined in [RFC5213] is used 916 for this. 918 6.2.6. GRE Key Option 920 This option is used to transfer the GRE Key for the MN's data flow 921 over the bi-directional tunnel between the PAR and NAR. The message 922 format of this option follows the GRE Key Option defined in [GREKEY]. 923 The GRE Key value uniquely identifies each flow and the sender of 924 this option expects to receive packets of the flow from the peer AR 925 with this value. 927 6.2.7. IPv4 Address Option 929 As described in Section 4.3, if the MN runs in IPv4-only mode or 930 dual-stack mode, it requires IPv4 home address (IPv4-MN-HoA). This 931 option is used to transfer the IPv4 home address if assigned on the 932 previous link. The format of this option follows the IPv4 Home 933 Address Option defined in [IPv4PMIPv6]. 935 6.2.8. Vendor-Specific Mobility Option 937 This option is used to transfer any other information defined in this 938 document. The format of this option follows the Vendor-Specific 939 Mobility Option defined in [RFC5094]. The exact values in the Vendor 940 ID, Sub-Type and Data fields are outside the scope of this document. 942 7. Security Considerations 944 Security issues for this document follow those for PMIPv6 [RFC5213] 945 and FMIPv6 [RFC5268bis]. In PMIPv6, the MAG and LMA are assumed to 946 share security associations. In FMIPv6, the access routers (i.e., 947 the PMAG and NMAG in this document) are assumed to share security 948 associations. 950 The Handover Initiate (HI) and Handover Acknowledgement (HAck) 951 messages exchanged between the PMAG and NMAG MUST be protected using 952 end-to-end security association(s) offering integrity and data origin 953 authentication. The PMAG and the NMAG MUST implement IPsec [RFC4301] 954 for protecting the HI and HAck messages. IPsec Encapsulating 955 Security Payload (ESP) [RFC4303] in transport mode with mandatory 956 integrity protection SHOULD be used for protecting the signaling 957 messages. Confidentiality protection SHOULD be used if sensitive 958 context related to the mobile node is transferred. 960 IPsec ESP [RFC4303] in tunnel mode MAY be used to protect the MN's 961 packets at the time of forwarding if protection of data traffic is 962 required. 964 8. IANA Considerations 966 This document defines four new mobility options, which are described 967 in Section 6.2. The Type value for these options are assigned from 968 the same numbering space as allocated for the other mobility options, 969 as defined in [RFC3775]. 971 Mobility Options 972 Value Description Reference 973 ----- ------------------------------------- ------------- 974 TBD1 Context Request Option Section 6.2.1 975 TBD2 Local Nobility Anchor Address Option Section 6.2.2 976 TBD3 Mobile Node Interface Identifier Option Section 6.2.3 978 9. Acknowledgments 980 The authors would like to specially thank Vijay Devarapalli and Sri 981 Gundavelli for their thorough reviews of this document. 983 The authors would also like to thank Charlie Perkins, Desire Oulai, 984 Ahmad Muhanna, Giaretta Gerardo, Domagoj Premec, Marco Liebsch, Fan 985 Zhao, Julien Laganier and Pierrick Seite for their passionate 986 discussions in the working group mailing list. 988 10. References 990 10.1. Normative References 992 [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., 993 and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. 995 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 996 Requirement Levels", BCP 14, RFC 2119, March 1997. 998 [RFC5268bis] 999 Koodli, R., Ed., "Mobile IPv6 Fast Handovers", 1000 draft-ietf-mipshop-rfc5268bis-01.txt, March 2009. 1002 [RFC3775] Johnson, D., "Mobility Support in IPv6", RFC 3775, 1003 June 2004. 1005 [RFC4988] Koodli, R. and C. Perkins, "Mobile IPv4 Fast Handovers", 1006 RFC 4988, October 2007. 1008 [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in 1009 IPv6 Specification", RFC 2473, December 1998. 1011 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 1012 Internet Protocol", RFC 4301, December 2005. 1014 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 1015 RFC 4303, December 2005. 1017 [RFC5094] Devarapalli, V., Patel, A., and K. Leung, "Mobile IPv6 1018 Vendor Specific Option", RFC 5094, December 2007. 1020 10.2. Informative References 1022 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 1023 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 1024 September 2007. 1026 [IPv4PMIPv6] 1027 Wakikawa, R., Ed. and S. Gundavelli, "IPv4 Support for 1028 Proxy Mobile IPv6", 1029 draft-ietf-netlmm-pmip6-ipv4-support-13.txt, June 2009. 1031 [GREKEY] Muhanna, A., Ed., "GRE Key Option for Proxy Mobile IPv6", 1032 draft-ietf-netlmm-grekey-option-09.txt, May 2009. 1034 Appendix A. Applicable Use Cases 1036 A.1. PMIPv6 Handoff Indication 1038 PMIPv6 [RFC5213] defines the Handoff Indicator Option and describes 1039 the type of the handoff and the values to set to the option. This 1040 document proposes one approach to determining the handoff type by the 1041 NMAG when the handoff of the MN is executed. 1043 According to [RFC5213], the following handoff types are defined: 1045 0) Reserved 1047 1) Attachment over a new interface 1049 2) Handoff between two different interfaces of the mobile node 1051 3) Handoff between mobile access gateways for the same interface 1053 4) Handoff state unknown 1055 5) Handoff state not changed (Re-registration) 1057 By using the MN Interface Identifier (MN IID) option, which is 1058 defined in this document, the following solution can be considered. 1059 When the NMAG receives the MN IID used in the P-AN from the PMAG via 1060 the HI or HAck messages, the NMAG compares it with the new MN IID 1061 that is obtained from the MN in the N-AN. If these two MN IIDs are 1062 the same, the handover type falls into 3) and the Handoff Indicator 1063 value is set to 3. If these two MN IIDs are different, the handover 1064 is likely to be 2) since the HI/HAck message exchange implies that 1065 this is a handover not a multi-homing, therefore the Handoff 1066 Indicator value can be set to 2. If there is no HI/HAck exchange 1067 performed prior to the network attachment of the MN in the new 1068 network, the NMAG may infer that this is a multi-homing case and set 1069 the Handoff Indicator value to 1. In the case of re-registration, 1070 the MAG, to which the MN is attached, can determine if the handoff 1071 state is not changed, so the MAG can set the HI value to 5 without 1072 any additional information. If none of them can be assumed, the NMAG 1073 may set the value to 4. 1075 A.2. Local Routing 1077 Section 6.10.3 in [RFC5213] describes that if EnableMAGLocalRouting 1078 flag is set, when two mobile nodes are attached to one MAG, the 1079 traffic between them may be locally routed. If one mobile node moves 1080 from this MAG (PMAG) to another MAG (NMAG) and if the PMAG does not 1081 detect the MN's detachment, it will continue to forward packets 1082 locally forever. This situation is more likely to happen in the 1083 reactive fast handover with WLAN access, which does not have the 1084 capability to detect the detachment of the MN in a timely manner. 1085 PFMIPv6 can be applied to handle this case. When the MN attaches to 1086 the NMAG, it sends the HI message to the PMAG, which makes it realize 1087 the detachment of the MN. The PMAG immediately stops the local 1088 routing and sends the packets for the MN towards the LMA, which in 1089 turn forwards them to the NMAG over the PMIPv6 tunnel. 1091 Appendix B. Change Log 1093 Changes at -00 1095 * Added separate sections for MH and ICMP. 1097 * Clarified usage of HNP and IPv4-MN-HoA throughout the document. 1099 * Added IANA Considerations. 1101 * Added section on Other Considerations, including operation of 1102 uplink packets when using link-layer addresses, multiple 1103 interface usage and transmission of RA to withdraw HNP in the 1104 event of failure of PMIP6 registration. 1106 * Revised Security Considerations. 1108 Changes from -00 to -01 1110 * Removed ICMPv6-based message format. 1112 * Clarified HI/HAck exchange in the predictive mode (step (e) in 1113 Figure 2). 1115 * Clarified information retrieval about the PMAG in the reactive 1116 mode. 1118 * Removed the extension to the GRE Key Option. 1120 * Clarified the handoff type considerations in Appendix A. 1122 * Home Network Prefix Option, Link-local Address Option and 1123 Vendor-Specific Mobility Option are added. 1125 Changes from -01 to -02 1127 * Aligned HI/HAck message formats with [RFC5268bis] 1128 (draft-ietf-mipshop-rfc5268bis-00.txt). 1130 * Revised Section 8 removing the request for the type assignment 1131 of HI/HAck Mobility Headers. 1133 Changes from -02 to -03 1135 * Updated HI/HAck message formats according to 1136 draft-ietf-mipshop-rfc5268bis-01.txt. 1138 * Cleaned up Figure 2 and Figure 3. 1140 * Moved PMIP domain boundary crossing situation in Section 4.1 to 1141 Appendix A.3. 1143 * Removed the alternative protocol operation with an unsolicited 1144 HAck from Section 4.1. 1146 * Modified Code values in the HAck message in order to avoid 1147 collision with those in [RFC5268bis]. 1149 * Clarified the usage scenarios of Context Request Option. 1151 * Modified the description of Code values in the HAck message. 1153 * Changed the container for the IPv4-LMAA from IPv4 Address 1154 option to the LMAA option. 1156 * Made Confidentiality protection "SHOULD" for context transfer. 1158 Changes from -03 to -04 1160 * Added more explanations about MIPv6, FMIPv6 and PMIPv6 in 1161 Abstract. 1163 * Moved Figure 1 to Section 4. 1165 * More clearly indicated the FMIPv6 messages that are not 1166 applicable in the PMIPv6 context. 1168 * Mandated the support of IP Sec on the PMAG and NMAG in order to 1169 protect signaling and user packets and the context information. 1171 * Added a new section for the inter-AR tunneling operation 1172 (Section 4.2). 1174 * Added descriptions about the encapsulation type in Sections 4.1 1175 and 4.3. 1177 * Added a description about buffering requirements on the MAG in 1178 Section 4.1. 1180 * Added a description about the timing of L2 and L3 connection 1181 establishments in Section 4.1. 1183 * Added a new section for PMIPv6-related fast handover issues 1184 (Section 5) and a description about preferable behaviors of the 1185 MN and MAG to reduce packet loss. 1187 * Added Acknowledgments section (Section 9). 1189 * Added a new section for local routing in Appendix (A.2). 1191 Changes from -04 to -05 1193 * Fixed Figure 2 (step (i)). 1195 * Defined the Mobile Network Interface Identifier (MN-IID) 1196 mobility option in Section 6.2.4 (swapped with old Section 1197 6.2.5), and added it to IANA considerations (Section 8). 1199 * Changed from SHOULD to MUST regarding the inclusion of the 1200 MN-ID, MN-HNP, MN-IID and the LMAA options in the HI message 1201 (step (c) in Section 4.1). 1203 * The optional behavior of the NMAG that allows it to send uplink 1204 packets directly to the LMA before the PBU/PBA exchange was 1205 removed from section 4.2 (as out of scope). 1207 * In Section A.3, the description about the HA address assignment 1208 from the NAR to the MN was removed (as out of scope). 1210 Changes from -05 to -06 1212 * Added 'P' flag in the HI and Hack messages to distinguish them 1213 from those in FMIPv6. 1215 * Made editorial corrections in Section 2 (Introduction), Section 1216 3 (Terminology), Section 4 (Protocol Overview) and Section 4.2 1217 (Inter-AR Tunneling Operation). 1219 * Added a description on how forwarded packets should be handled 1220 in the access network at step (f) in Section 4.1. 1222 * Added all types of encapsulation methods that should be 1223 supported in Section 4.1. 1225 * Revised the Code values for the HI message in Section 6.1.1. 1227 * Revised the Code values for the HAck message in Section 6.1.2 1228 and added a description of its usage at step (d) of the 1229 reactive handover mode in Section 4.1. 1231 * Removed the definition of the IP Address Option in Section 1232 6.2.3 and moved to Section 6.2.7, which currently refers to the 1233 IPv4 Home Address Option defined by RFC5555. Revised the IANA 1234 Consideration section accordingly. 1236 * Removed the Option-Code from the Mobile Node Identifier (MN 1237 IID) Option. 1239 * Removed Appendix A.3 (Handling of PMIPv6/MIPv6 switching). 1241 Changes from -06 to -07 1243 * Added explanations about defining and setting the 'P' flag for 1244 the HI and Hack messages in Sections 4 and 4.1. 1246 * Corrected the references for the encapsulation types in Section 1247 4.1. 1249 * Modified the Code values for the HI message in Section 6.1.1 to 1250 avoid overlapping with those in [RFC5268bis]. 1252 * Modified the reference for the IPv4 Address Option from RFC5555 1253 to [IPv4PMIPv6] in Section 6.2.7. 1255 Authors' Addresses 1257 Hidetoshi Yokota 1258 KDDI Lab 1259 2-1-15 Ohara, Fujimino 1260 Saitama, 356-8502 1261 JP 1263 Email: yokota@kddilabs.jp 1265 Kuntal Chowdhury 1266 Starent Networks 1267 30 International Place 1268 Tewksbury, MA 01876 1269 US 1271 Email: kchowdhury@starentnetworks.com 1273 Rajeev Koodli 1274 Starent Networks 1275 30 International Place 1276 Tewksbury, MA 01876 1277 US 1279 Email: rkoodli@starentnetworks.com 1281 Basavaraj Patil 1282 Nokia 1283 6000 Connection Drive 1284 Irving, TX 75039 1285 US 1287 Email: basavaraj.patil@nokia.com 1289 Frank Xia 1290 Huawei USA 1291 1700 Alma Dr. Suite 500 1292 Plano, TX 75075 1293 US 1295 Email: xiayangsong@huawei.com