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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Missing Reference: 'AP ID' is mentioned on line 356, but not defined == Missing Reference: 'AR-Info' is mentioned on line 356, but not defined ** Obsolete normative reference: RFC 3775 (Obsoleted by RFC 6275) ** Obsolete normative reference: RFC 5226 (Obsoleted by RFC 8126) Summary: 3 errors (**), 0 flaws (~~), 3 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: October 10, 2010 R. Koodli 6 Cisco Systems 7 B. Patil 8 Nokia 9 F. Xia 10 Huawei USA 11 April 8, 2010 13 Fast Handovers for Proxy Mobile IPv6 14 draft-ietf-mipshop-pfmipv6-13.txt 16 Abstract 18 Mobile IPv6 (MIPv6) [RFC3775] provides a mobile node with IP mobility 19 when it performs a handover from one MAG to another and fast 20 handovers for Mobile IPv6 (FMIPv6) [RFC5568] are specified to enhance 21 the handover performance in terms of latency and packet loss. While 22 MIPv6 (and FMIPv6 as well) requires the participation of the mobile 23 node in the mobility-related signaling, Proxy Mobile IPv6 (PMIPv6) 24 [RFC5213] provides IP mobility to mobile nodes that either have or do 25 not have MIPv6 functionality without such involvement. Nevertheless, 26 the basic performance of PMIPv6 in terms of handover latency and 27 packet loss is considered not any different from that of MIPv6. 29 When the fast handover is considered in such an environment, several 30 modifications are needed to FMIPv6 to adapt to the network-based 31 mobility management. This document specifies the usage of Fast 32 Mobile IPv6 (FMIPv6) when Proxy Mobile IPv6 is used as the mobility 33 management protocol. Necessary extensions are specified for FMIPv6 34 to support the scenario when the mobile node does not have IP 35 mobility functionality and hence is not involved with either MIPv6 or 36 FMIPv6 operations. 38 Status of this Memo 40 This Internet-Draft is submitted in full conformance with the 41 provisions of BCP 78 and BCP 79. 43 Internet-Drafts are working documents of the Internet Engineering 44 Task Force (IETF). Note that other groups may also distribute 45 working documents as Internet-Drafts. The list of current Internet- 46 Drafts is at http://datatracker.ietf.org/drafts/current/. 48 Internet-Drafts are draft documents valid for a maximum of six months 49 and may be updated, replaced, or obsoleted by other documents at any 50 time. It is inappropriate to use Internet-Drafts as reference 51 material or to cite them other than as "work in progress." 53 This Internet-Draft will expire on October 10, 2010. 55 Copyright Notice 57 Copyright (c) 2010 IETF Trust and the persons identified as the 58 document authors. All rights reserved. 60 This document is subject to BCP 78 and the IETF Trust's Legal 61 Provisions Relating to IETF Documents 62 (http://trustee.ietf.org/license-info) in effect on the date of 63 publication of this document. Please review these documents 64 carefully, as they describe your rights and restrictions with respect 65 to this document. Code Components extracted from this document must 66 include Simplified BSD License text as described in Section 4.e of 67 the Trust Legal Provisions and are provided without warranty as 68 described in the Simplified BSD License. 70 This document may contain material from IETF Documents or IETF 71 Contributions published or made publicly available before November 72 10, 2008. The person(s) controlling the copyright in some of this 73 material may not have granted the IETF Trust the right to allow 74 modifications of such material outside the IETF Standards Process. 75 Without obtaining an adequate license from the person(s) controlling 76 the copyright in such materials, this document may not be modified 77 outside the IETF Standards Process, and derivative works of it may 78 not be created outside the IETF Standards Process, except to format 79 it for publication as an RFC or to translate it into languages other 80 than English. 82 Table of Contents 84 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 4 85 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 86 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 87 4. Proxy-based FMIPv6 Protocol Overview . . . . . . . . . . . . . 7 88 4.1. Protocol Operation . . . . . . . . . . . . . . . . . . . . 8 89 4.2. Inter-AR Tunneling Operation . . . . . . . . . . . . . . . 15 90 4.3. IPv4 Support Considerations . . . . . . . . . . . . . . . 17 91 5. PMIPv6-related Fast Handover Issues . . . . . . . . . . . . . 18 92 5.1. Manageability Considerations . . . . . . . . . . . . . . . 18 93 5.2. Expedited Packet Transmission . . . . . . . . . . . . . . 18 94 6. Message Formats . . . . . . . . . . . . . . . . . . . . . . . 20 95 6.1. Mobility Header . . . . . . . . . . . . . . . . . . . . . 20 96 6.1.1. Handover Initiate (HI) . . . . . . . . . . . . . . . . 20 97 6.1.2. Handover Acknowledge (HAck) . . . . . . . . . . . . . 22 98 6.2. Mobility Options . . . . . . . . . . . . . . . . . . . . . 24 99 6.2.1. Context Request Option . . . . . . . . . . . . . . . . 24 100 6.2.2. Local Mobility Anchor Address (LMAA) Option . . . . . 25 101 6.2.3. Mobile Node Link-local Address Interface 102 Identifier (MN LLA-IID) Option . . . . . . . . . . . . 26 103 6.2.4. Home Network Prefix Option . . . . . . . . . . . . . . 27 104 6.2.5. Link-local Address Option . . . . . . . . . . . . . . 27 105 6.2.6. GRE Key Option . . . . . . . . . . . . . . . . . . . . 27 106 6.2.7. IPv4 Address Option . . . . . . . . . . . . . . . . . 27 107 6.2.8. Vendor-Specific Mobility Option . . . . . . . . . . . 27 108 7. Security Considerations . . . . . . . . . . . . . . . . . . . 28 109 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29 110 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 31 111 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 32 112 10.1. Normative References . . . . . . . . . . . . . . . . . . . 32 113 10.2. Informative References . . . . . . . . . . . . . . . . . . 32 114 Appendix A. Applicable Use Cases . . . . . . . . . . . . . . . . 33 115 A.1. PMIPv6 Handoff Indication . . . . . . . . . . . . . . . . 33 116 A.2. Local Routing . . . . . . . . . . . . . . . . . . . . . . 33 117 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 35 118 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 41 120 1. Requirements notation 122 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 123 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 124 document are to be interpreted as described in [RFC2119]. 126 2. Introduction 128 Proxy Mobile IPv6 [RFC5213] provides IP mobility to a mobile node 129 that does not support Mobile IPv6 [RFC3775] mobile node 130 functionality. A proxy agent in the network performs the mobility 131 management signaling on behalf of the mobile node. This model 132 transparently provides mobility for mobile nodes within a PMIPv6 133 domain. Nevertheless, the basic performance of PMIPv6 in terms of 134 handover latency and packet loss is considered not any different from 135 that of Mobile IPv6. 137 Fast Handovers for Mobile IPv6 (FMIPv6) [RFC5568] describes the 138 protocol to reduce the handover latency for Mobile IPv6 by allowing a 139 mobile node to send packets as soon as it detects a new subnet link 140 and by delivering packets to the mobile node as soon as its 141 attachment is detected by the new access router. This document 142 extends FMIPv6 for Proxy MIPv6 operation to minimize handover delay 143 and packet loss as well as to transfer network-resident context for a 144 PMIPv6 handover. [RFC5568] should be considered normative for this 145 document, except where this document specifies new or revised 146 functions and messages. 148 3. Terminology 150 This document reuses terminology from [RFC5213], [RFC5568] and 151 [RFC3775]. The following terms and abbreviations are additionally 152 used in this document. 154 Access Network (AN): 155 A network composed of link-layer access devices such as access 156 points or base stations providing access to a MAG (Mobile Access 157 Gateway) connected to it. 159 Previous Access Network (P-AN): 160 The access network to which the Mobile Node (MN) is attached 161 before handover. 163 New Access Network (N-AN): 164 The access network to which the Mobile Node (MN) is attached 165 after handover. 167 Previous Mobile Access Gateway (PMAG): 168 The MAG that manages mobility related signaling for the mobile 169 node before handover. In this document, the MAG and the Access 170 Router are co-located. 172 New Mobile Access Gateway (NMAG): 173 The MAG that manages mobility related signaling for the mobile 174 node after handover. In this document, the MAG and the Access 175 Router (AR) are co-located. 177 Local Mobility Anchor (LMA): 178 The topological anchor point for the mobile node's home network 179 prefix(es) and the entity that manages the mobile node's binding 180 state. This specification does not alter any capability or 181 functionality defined in [RFC5213]. 183 Handover indication: 184 A generic signaling message, sent from the P-AN to the PMAG that 185 indicates a mobile node's handover. While this signaling is 186 dependent on the access technology, it is assumed that Handover 187 indication can carry the information to identify the mobile node 188 and to assist the PMAG to resolve the NMAG and the new access 189 point or base station to which the mobile node is moving to. 190 The details of this message are outside the scope of this 191 document. 193 4. Proxy-based FMIPv6 Protocol Overview 195 This specification describes fast handover protocols for the network- 196 based mobility management protocol called Proxy Mobile IP (PMIPv6) 197 [RFC5213]. The core functional entities defined in PMIPv6 are the 198 Local Mobility Anchor (LMA) and the Mobile Access Gateway (MAG). The 199 LMA is the topological anchor point for the mobile node's home 200 network prefix(es). The MAG acts as an access router (AR) for the 201 mobile node and performs the mobility management procedures on its 202 behalf. The MAG is responsible for detecting the mobile node's 203 movements to and from the access link and for initiating binding 204 registrations to the mobile node's local mobility anchor. If the 205 MAGs can be informed of the detachment and/or attachment of the 206 mobile node in a timely manner via e.g., the lower layer signaling, 207 it will become possible to optimize the handover procedure, which 208 involves establishing a connection on the new link and signaling 209 between mobility agents, compared to the baseline specification of 210 PMIPv6. 212 In order to further improve the performance during the handover, the 213 PFMIPv6 protocol in this document specifies a bi-directional tunnel 214 between the Previous MAG (PMAG) and the New MAG (NMAG) to tunnel 215 packets meant for the mobile node. In order to enable the NMAG to 216 send the Proxy Binding Update (PBU), the Handover Initiate (HI) and 217 Handover Acknowledge (HAck) messages in [RFC5568] are extended for 218 context transfer, in which parameters such as mobile node's Network 219 Access Identifier (NAI), Home Network Prefix (HNP), IPv4 Home 220 Address, are transferred from the PMAG. New flags 'P' and 'F' are 221 defined for the HI and HAck messages to distinguish from those in 222 [RFC5568] and to request packet forwarding, respectively. 224 In this document, the Previous Access Router (PAR) and New Access 225 Router (NAR) are interchangeable with the PMAG and NMAG, 226 respectively. The reference network is illustrated in Figure 1. The 227 access networks in the figure (i.e., P-AN and N-AN) are composed of 228 Access Points (APs) defined in [RFC5568], which are often referred to 229 as base stations in cellular networks. 231 Since a mobile node is not directly involved with IP mobility 232 protocol operations, it follows that the mobile node is not directly 233 involved with fast handover procedures either. Hence, the messages 234 involving the mobile node in [RFC5568] are not used when PMIPv6 is in 235 use. More specifically, the Router Solicitation for Proxy 236 Advertisement (RtSolPr), the Proxy Router Advertisement (PrRtAdv), 237 Fast Binding Update (FBU), Fast Binding Acknowledgment (FBack) and 238 the Unsolicited Neighbor Advertisement (UNA) messages are not 239 applicable in the PMIPv6 context. 241 +----------+ 242 | LMA | 243 | | 244 +----------+ 245 / \ 246 / \ 247 / \ 248 +........../..+ +..\..........+ 249 . +-------+-+ .______. +-+-------+ . 250 . | PMAG |()_______)| NMAG | . 251 . | (PAR) | . . | (NAR) | . 252 . +----+----+ . . +----+----+ . 253 . | . . | . 254 . ___|___ . . ___|___ . 255 . / \ . . / \ . 256 . ( P-AN ) . . ( N-AN ) . 257 . \_______/ . . \_______/ . 258 . | . . | . 259 . +----+ . . +----+ . 260 . | MN | ----------> | MN | . 261 . +----+ . . +----+ . 262 +.............+ +.............+ 264 Figure 1: Reference network for fast handover 266 4.1. Protocol Operation 268 There are two modes of operation in FMIPv6 [RFC5568]. In the 269 predictive mode of fast handover, a bi-directional tunnel between the 270 PMAG (PAR) and NMAG (NAR) is established prior to the mobile node's 271 attachment to the NMAG. In the reactive mode, this tunnel 272 establishment takes place after the mobile node attaches to the NMAG. 273 In order to alleviate the packet loss during a mobile node's handover 274 (especially when the mobile node is detached from both links), the 275 downlink packets for the mobile node need to be buffered either at 276 the PMAG or NMAG, depending on when the packet forwarding is 277 performed. It is hence required that all MAGs have the capability 278 and enough resources to buffer packets for the mobile nodes 279 accommodated by them. The buffer size to be prepared and the rate at 280 which buffered packets are drained are addressed in Section 5.4 of 281 [RFC5568]. Note that the protocol operation specified in the 282 document is transparent to the local mobility anchor (LMA), hence 283 there is no new functional requirement or change on the LMA. 285 Unlike MIPv6, the mobile node in the PMIPv6 domain is not involved 286 with IP mobility signaling; therefore, in order for the predictive 287 fast handover to work effectively, it is required that the mobile 288 node is capable of reporting lower-layer information to the AN at a 289 short enough interval, and the AN is capable of sending the Handover 290 indication to the PMAG at an appropriate timing. The sequence of 291 events for the predictive fast handover are illustrated in Figure 2. 293 PMAG NMAG 294 MN P-AN N-AN (PAR) (NAR) LMA 295 | | | | | | 296 (a) |--Report-->| | | | | 297 | | | | | | 298 | | Handover | | | 299 (b) | |------indication------>| | | 300 | | | | | | 301 | | | | | | 302 (c) | | | |----HI---->| | 303 | | | | | | 304 | | | | | | 305 (d) | | | |<---HAck---| | 306 | | | | | | 307 | | | | | | 308 | | | |HI/HAck(optional) | 309 (e) | | | |<- - - - ->| | 310 | | | #=|<===================| 311 (f) | | | #====DL data=>| | 312 | Handover | Handover | | | 313 (g) |<-command--|<------command---------| | | 314 ~~~ | | | | | 315 ~~~ | | | | | 316 | MN-AN connection | AN-MAG connection | | 317 (h) |<---establishment---->|<----establishment----->| | 318 | | | (substitute for UNA) | | 319 | | | | | | 320 (i) |<==================DL data=====================| | 321 | | | | | | 322 (j) |===================UL data====================>|=# | 323 | | | #=|<============# | 324 | | | #=====================>| 325 / | | | | | | \ 326 |(k) | | | | |--PBU-->| | 327 | | | | | | | | 328 |(l) | | | | |<--PBA--| | 329 | |<==================DL data=====================|<=======| | 330 | | | | | | | | 331 \ |===================UL data====================>|=======>| / 333 Figure 2: Predictive fast handover for PMIPv6 (PMAG initiated) 335 The detailed descriptions are as follows: 337 (a) The mobile node detects that a handover is imminent and reports 338 the identifier of itself (MN ID) and the New Access Point 339 Identifier (New AP ID) [RFC5568] to which the mobile node is 340 most likely to move. The MN ID could be the NAI, Link-layer 341 address, or any other suitable identifier, but the MAG SHOULD be 342 able to map any access specific identifier to the NAI as the MN 343 ID. In some cases, the previous access network (P-AN) will 344 determine the New AP ID for the mobile node. This step is 345 access technology specific and details are outside the scope of 346 this document. 348 (b) The previous access network, to which the mobile node is 349 currently attached, indicates the handover of the mobile node to 350 the previous mobile access gateway (PMAG), with the MN ID and 351 New AP ID. Detailed definition and specification of this 352 message are outside the scope of this document. 354 (c) The previous MAG derives the new mobile access gateway (NMAG) 355 from the New AP ID, which is a similar process to that of 356 constructing an [AP ID, AR-Info] tuple in [RFC5568]. The 357 previous MAG then sends the Handover Initiate (HI) message to 358 the new MAG. The HI message MUST have the P flag set and 359 include the MN ID, the HNP(s) and the address of the local 360 mobility anchor that is currently serving the mobile node. If 361 there is a valid (non-zero) MN Link-layer Identifier (MN LL-ID), 362 that information MUST also be included. With some link layers, 363 the MN Link-local Address IID (MN LLA-IID) can also be included 364 (see Section 6.2.3). 366 (d) The new MAG sends the Handover Acknowledge (HAck) message back 367 to the previous MAG with the P flag set. 369 (e) If it is preferred that the timing of buffering or forwarding 370 should be later than step (c), the new MAG may optionally 371 request the previous MAG at a later and appropriate time to 372 buffer or forward packets by setting U flag [RFC5568] or F flag 373 in the HI message, respectively. 375 (f) If the F flag is set in the previous step, a bi-directional 376 tunnel is established between the previous MAG and new MAG and 377 packets destined for the mobile node are forwarded from the 378 previous MAG to the new MAG over this tunnel. After 379 decapsulation, those packets may be buffered at the new MAG. If 380 the connection between the new access network and new MAG has 381 already been established, those packets may be forwarded towards 382 the new access network, which then becomes responsible for them 383 (e.g., buffering or delivering depending on the condition of the 384 mobile node's attachment); this is access technology specific. 386 (g) When handover is ready on the network side, the mobile node is 387 triggered to perform handover to the new access network. This 388 step is access technology specific and details are outside the 389 scope of this document. 391 (h) The mobile node establishes a physical link connection with the 392 new access network (e.g., radio channel assignment), which in 393 turn triggers the establishment of a link-layer connection 394 between the new access network and new MAG if not yet 395 established. An IP layer connection setup may be performed at 396 this time (e.g., PPP IPv6CP) or at a later time (e.g., stateful 397 or stateless auto address configuration). This step can be a 398 substitute for the Unsolicited Neighbor Advertisement (UNA) in 399 [RFC5568]. If the new MAG acquires a valid new MN LL-ID via the 400 new access network and a valid old MN LL-ID from the previous 401 MAG at step (c), these IDs SHOULD be compared to determine 402 whether the same interface is used before and after handover. 403 When the connection between the mobile node and new MAG is PPP 404 and the same interface is used for the handover, the new MAG 405 SHOULD confirm that the same interface identifier is used for 406 the mobile node's link-local address (this is transferred from 407 previous MAG using the MN LLA-IID option at step (c), and sent 408 to the mobile node during the Configure-Request/Ack exchange). 410 (i) The new MAG starts to forward packets destined for the mobile 411 node via the new access network. 413 (j) The uplink packets from the mobile node are sent to the new MAG 414 via the new access network and the new MAG forwards them to the 415 previous MAG. The previous MAG then sends the packets to the 416 local mobility anchor that is currently serving the mobile node. 418 (k) The new MAG sends the Proxy Binding Update (PBU) to the local 419 mobility anchor, whose address is provided in (c). Steps (k) 420 and (l) are not part of the fast handover procedure, but shown 421 for reference. 423 (l) The local mobility anchor sends back the Proxy Binding 424 Acknowledgment (PBA) to the new MAG. From this time on, the 425 packets to/from the mobile node go through the new MAG instead 426 of the previous MAG. 428 According to Section 4 of [RFC5568], the previous MAG establishes a 429 binding between the Previous Care-of Address (PCoA) and New Care-of 430 Address (NCoA) to forward packets for the mobile node to the new MAG, 431 and the new MAG creates a proxy neighbor cache entry to receive those 432 packets for the NCoA before the mobile node arrives. In the case of 433 PMIPv6, however, the only address that is used by the mobile node is 434 MN-HoA (Mobile Node's Home Address), so the PMAG forwards mobile 435 node's packets to the NMAG instead of the NCoA. The NMAG then simply 436 decapsulates those packets and delivers them to the mobile node. 437 FMIPv4 [RFC4988] specifies forwarding when the mobile node uses the 438 home address as its on-link address rather than the care-of address. 439 The usage in PMIPv6 is similar to that in FMIPv4, where the 440 address(es) used by the mobile node is/are based on its HNP(s). 441 Since the NMAG can obtain the Link-layer address (MN LL-ID) and 442 HNP(s) via the HI message (also the interface identifier of the 443 mobile node's link-local address (MN LLA-ID) if available), it can 444 create a neighbor cache entry for the Link-local Address and the 445 routes for the whole HNP(s) even before the mobile node performs 446 Neighbor Discovery. For the uplink packets from the mobile node 447 after handover in (j), the NMAG forwards the packets to the PMAG 448 through the tunnel established in step (f). The PMAG then 449 decapsulates and sends them to the local mobility anchor. 451 The timing of the context transfer and that of packet forwarding may 452 be different. Thus, a new flag 'F' and Option Code values for it in 453 the HI and HAck messages are defined to request forwarding. To 454 request buffering, 'U' flag has already been defined in [RFC5568]. 455 If the PMAG receives the HI message with the F flag set, it starts 456 forwarding packets for the mobile node. The HI message with the U 457 flag set may be sent earlier if the timing of buffering is different 458 from that of forwarding. If packet forwarding is completed, the PMAG 459 MAY send the HI message with the F flag set and the Option Code value 460 being 2. By this message, the ARs on both ends can tear down the 461 forwarding tunnel synchronously. 463 The IP addresses in the headers of those user packets are summarized 464 below: 466 In Step (f), 468 Inner source address: IP address of the correspondent node 470 Inner destination address: HNP or Mobile Node's IPv4 Home 471 Address (IPv4-MN-HoA) 473 Outer source address: IP address of the PMAG 475 Outer destination address: IP address of the NMAG 477 In Step (i), 478 Source address: IP address of the correspondent node 480 Destination address: HNP or IPv4-MN-HoA 482 In Step (j), 484 - from the mobile node to the NMAG, 486 Source address: HNP or IPv4-MN-HoA 488 Destination address: IP address of the correspondent node 490 - from the NMAG to the PMAG, 492 Inner source address: HNP or IPv4-MN-HoA 494 Inner destination address: IP address of the correspondent node 496 Outer source address: IP address of the NMAG 498 Outer destination address: IP address of the PMAG 500 - from the PMAG to the LMA, 502 Inner source address: HNP or IPv4-MN-HoA 504 Inner destination address: IP address of the correspondent node 506 Outer source address: IP address of the PMAG 508 Outer destination address: IP address of the LMA 510 In the case of the reactive handover for PMIPv6, since the mobile 511 node does not send either the FBU or UNA, it would be more natural 512 that the NMAG sends the HI to the PMAG after the mobile node has 513 moved to the new link. The NMAG then needs to obtain the information 514 of the PMAG beforehand. Such information could be provided, for 515 example, by the mobile node sending the AP-ID on the old link and/or 516 by the lower-layer procedures between the P-AN and N-AN. The exact 517 method is not specified in this document. Figure 3 illustrates the 518 reactive fast handover procedures for PMIPv6, where the bi- 519 directional tunnel establishment is initiated by the NMAG. 521 PMAG NMAG 522 MN P-AN N-AN (PAR) (NAR) LMA 523 | | | | | | 524 (a) ~~~ | | | | | 525 ~~~ | | | | | 526 | MN-AN connection | AN-MAG connection | | 527 (b) |<--establishment-->|<-------establishment------>| | 528 | | |(substitute for UNA and FBU)| | 529 | | | | | | 530 | | | | | | 531 (c) | | | |<-----HI-------| | 532 | | | | | | 533 | | | | | | 534 (d) | | | |-----HAck----->| | 535 | | | | | | 536 | | | | | | 537 (e) | | | #=|<=======================| 538 | | | #================>|=# | 539 |<====================DL data======================# | 540 | | | | | | 541 (f) |=====================UL data===================>|=# | 542 | | | #=|<================# | 543 | | | #=========================>| 544 | | | | | | 545 / | | | | | | \ 546 |(g) | | | | |--PBU-->| | 547 | | | | | | | | 548 |(h) | | | | |<--PBA--| | 549 | |<====================DL data====================|<=======| | 550 | | | | | | | | 551 \ |=====================UL data===================>|=======>| / 553 Figure 3: Reactive fast handover for PMIPv6 (NMAG initiated) 555 The detailed descriptions are as follows: 557 (a) The mobile node undergoes handover from the previous access 558 network to the new access network. 560 (b) The mobile node establishes a connection (e.g., radio channel) 561 with the new access network, which triggers the establishment of 562 the connection between the new access network and new MAG. The 563 MN ID is transferred to the new MAG at this step for the 564 subsequent procedures. The AP-ID on the old link (Old AP ID), 565 which will be provided by either the mobile node or the new 566 access network, is also transferred to the new MAG to help 567 identify the previous MAG on the new link. This can be regarded 568 as a substitute for the UNA and FBU. 570 (c) The new MAG sends the HI to the previous MAG. The HI message 571 MUST have the P flag set and include the MN ID. The Context 572 Request Option MAY be included to request additional context 573 information on the mobile node to the previous MAG. 575 (d) The previous MAG sends the HAck back to the new MAG with the P 576 flag set. The HAck message MUST include the HNP(s) and/or IPv4- 577 MN-HoA that is corresponding to the MN ID in the HI message and 578 SHOULD include the MN LL-ID, only if it is valid (non zero), and 579 the local mobility anchor address that is currently serving the 580 mobile node. The context information requested by the new MAG 581 MUST be included. If the requested context is not available for 582 some reason, the previous MAG MUST return the HAck with the Code 583 value 131. If the F flag is set in the HI at step (c) and 584 forwarding is nevertheless not executable for some reason, the 585 previous MAG MUST return the HAck with the Code value 132. 587 (e) If the F flag in the HI is set at step (c), a bi-directional 588 tunnel is established between the previous MAG and new MAG and 589 packets destined for the mobile node are forwarded from the 590 previous MAG to the new MAG over this tunnel. After 591 decapsulation, those packets are delivered to the mobile node 592 via the new access network. 594 (f) The uplink packets from the mobile node are sent to the new MAG 595 via the new access network and the new MAG forwards them to the 596 previous MAG. The previous MAG then sends the packets to the 597 local mobility anchor that is currently serving the mobile node. 599 Steps (g)-(h) are the same as (k)-(l) in the predictive fast handover 600 procedures. 602 In step (c), the IP address of the PMAG needs to be resolved by the 603 NMAG to send the HI to the PMAG. This information may come from the 604 N-AN or some database that the NMAG can access. 606 4.2. Inter-AR Tunneling Operation 608 When the PMAG (PAR) or NMAG (NAR), depending on the fast handover 609 mode, receives the HI message with the F flag set, it prepares to 610 send/receive the mobile node's packets to/from the other MAG and 611 returns the HAck message with the same sequence number. The both 612 MAGs SHOULD support the following encapsulation modes for the user 613 packets, which are also defined for the tunnel between the local 614 mobility anchor and MAG: 616 o IPv4-or-IPv6-over-IPv6 [IPv4PMIPv6] 617 o IPv4-or-IPv6-over-IPv4 [IPv4PMIPv6] 619 o IPv4-or-IPv6-over-IPv4-UDP [IPv4PMIPv6] 621 o TLV-header UDP tunneling [GREKEY] 623 o GRE tunneling with or without GRE key(s) [GREKEY] 625 The PMAG and the NMAG MUST use the same tunneling mechanism for the 626 data traffic tunneled between them. The encapsulation mode to be 627 employed SHOULD be configurable. This specification recommends the 628 following: 630 1. As the default behavior, the inter-MAG tunnel uses the same 631 encapsulation mechanism as that for the PMIPv6 tunnel between the 632 local mobility anchor and the MAGs. The PMAG and NMAG 633 automatically start using the same encapsulation mechanism 634 without a need for a special configuration on the MAGs or a 635 dynamic tunneling mechanism negotiation between them. 637 2. Configuration on the MAGs can override the default mechanism 638 specified in #1 above. The PMAG and NMAG MUST be configured with 639 the same mechanism and this configuration is most likely to be 640 uniform throughout the PMIPv6 domain. If the packets on the 641 PMIPv6 tunnel cannot be uniquely mapped on to the configured 642 inter-MAG tunnel, this scenario is not applicable and scenario #3 643 below SHOULD directly be applied. 645 3. An implicit or explicit tunnel negotiation mechanism between the 646 MAGs can override the default mechanism specified in #1 above. 647 The employed tunnel negotiation mechanism is outside the scope of 648 this document. 650 The necessary information MUST be transferred in the HI/HAck messages 651 to distinguish mobile node's packets for forwarding in advance or at 652 this time. Such information includes the HNP(s) (or IPv4-MN-HoA) 653 and/or GRE key(s). In the case of GRE tunneling with GRE keys being 654 used, for each mobility session, the NMAG selects the GRE key for the 655 downlink packets and the PMAG selects the GRE key for the uplink 656 packets. These GRE keys are exchanged between the PMAG and the NMAG 657 using the GRE Key option as described in [GREKEY], e.g., In the case 658 of the reactive mode as shown in Figure 3, the DL GRE key is 659 communicated in the HI message while the UL GRE key is sent in the 660 HAck message. For the downlink packets, the PMAG redirects mobile 661 node's packets from the local mobility anchor towards the NMAG and if 662 the mobile node is ready to receive those packets or the N-AN can 663 handle them regardless of the state of the mobile node, the NMAG 664 should immediately send them towards the N-AN; otherwise it should 665 buffer them until the mobile node is ready. For the uplink packets, 666 the NMAG SHOULD reverse-tunnel them from the mobile node towards the 667 PMAG and the PMAG sends them to the local mobility anchor. 669 When the PMAG or NMAG receives the HI message with the U flag set, it 670 prepares to buffer the mobile node's packets and returns the HAck 671 message with the same sequence number. It MUST be followed by 672 another HI message with the F flag set at an appropriate time to 673 forward the buffered packets. 675 If the MAG that received the HI message encounters an erroneous 676 situation (e.g., insufficient buffer space), it SHOULD immediately 677 send the HAck message with the cause of the error and cancel all 678 tunneling operation. 680 4.3. IPv4 Support Considerations 682 The motivation and usage scenarios of IPv4 protocol support by PMIPv6 683 are described in [IPv4PMIPv6]. The scope of IPv4 support covers the 684 following two features: 686 o IPv4 Home Address Mobility Support, and 688 o IPv4 Transport Support. 690 As for IPv4 Home Address Mobility Support, the mobile node acquires 691 IPv4 Home Address (IPv4-MN-HoA) and in the case of handover, the PMAG 692 needs to transfer IPv4-MN-HoA to the NMAG, which is the inner 693 destination address of the packets forwarded on the downlink. For 694 this purpose, IPv4 Address Option described in Section 6.2.7 is used. 695 In order to provide IPv4 Transport Support, the NMAG needs to know 696 the IPv4 address of the local mobility anchor (IPv4-LMAA) to send 697 PMIPv6 signaling messages to the local mobility anchor in the IPv4 698 transport network. For this purpose, a new option called LMA Address 699 (LMAA) Option is defined in Section 6.2.2 so as to convey IPv4-LMAA 700 from the PMAG to NMAG. 702 5. PMIPv6-related Fast Handover Issues 704 5.1. Manageability Considerations 706 This specification does not require any additional IP-level 707 functionality on the local mobility anchor and the mobile node 708 running in the PMIPv6 domain. A typical network interface that the 709 mobile node could be assumed to have is one with the cellular 710 network, where the network controls the movement of the mobile node. 711 Different types of interfaces could be involved such as different 712 generations (3G and 3.9G) or different radio access systems. This 713 specification supports a mobile node with the single radio mode, 714 where only one interface is active at any given time. The assigned 715 IP address is preserved whether the physical interface changes or not 716 and the mobile node can identify which interface should be used if 717 there are multiple ones. 719 5.2. Expedited Packet Transmission 721 The protocol specified in this document enables the NMAG to obtain 722 parameters which would otherwise be available only by communicating 723 with the local mobility anchor. For instance, the HNP(s) and/or 724 IPv4-MN-HoA of a mobile node are made available to the NMAG through 725 context transfer. This allows the NMAG to perform some procedures 726 that may be beneficial. The NMAG, for example, could send a Router 727 Advertisement (RA) with the HNP option to the mobile node as soon as 728 its link attachment is detected (e.g., via receipt of a Router 729 Solicitation message). Such an RA is recommended, for example, in 730 scenarios where the mobile node uses a new radio interface while 731 attaching to the NMAG; since the mobile node does not have 732 information regarding the new interface, it will not be able to 733 immediately send packets without first receiving an RA with HNP(s). 734 Especially, in the reactive fast handover, the NMAG gets to know the 735 HNP(s) assigned to the mobile node on the previous link at step (d) 736 in Figure 3. In order to reduce the communication disruption time, 737 the NMAG SHOULD expect the mobile node to keep using the same HNP and 738 to send uplink packets before that step upon the mobile node's 739 request. However, if the HAck from the PMAG returns a different HNP 740 or the subsequent PMIPv6 binding registration for the HNP fails for 741 some reason, then the NMAG MUST withdraw the advertised HNP by 742 sending another RA with zero prefix lifetime for the HNP in question. 743 This operation is the same as described in Section 6.12 of [RFC5213]. 745 The protocol specified in this document is applicable regardless of 746 whether link-layer addresses are used between a mobile node and its 747 MAG. A mobile node should be able to continue sending packets on the 748 uplink even when it changes link. When link-layer addresses are 749 used, the mobile node performs Neighbor Unreachability Detection 750 (NUD) [RFC4861], after attaching to a new link, probing the 751 reachability of its default router. The new router should respond to 752 the NUD probe, providing its link-layer address in the solicited 753 Neighbor Advertisement, which is common in the PMIPv6 domain. 754 Implementations should allow the mobile node to continue to send 755 uplink packets while it is performing NUD. 757 6. Message Formats 759 This document defines new Mobility Header messages for the extended 760 HI and Hack and new mobility options for conveying context 761 information. 763 6.1. Mobility Header 765 6.1.1. Handover Initiate (HI) 767 This section defines extensions to the HI message in [RFC5568]. The 768 format of the Message Data field in the Mobility Header is as 769 follows: 771 0 1 2 3 772 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 1 773 +-------------------------------+ 774 | Sequence # | 775 +-+-+-+-+-------+---------------+-------------------------------+ 776 |S|U|P|F|Resv'd | Code | | 777 +-+-+-+-+-------+---------------+ | 778 | | 779 . . 780 . Mobility options . 781 . . 782 | | 783 +---------------------------------------------------------------+ 784 (Note:P=1) 786 IP Fields: 788 Source Address 790 The IP address of PMAG or NMAG 792 Destination Address 794 The IP address of the peer MAG 796 Message Data: 798 Sequence # Same as [RFC5568]. 800 S flag Defined in [RFC5568] and MUST be set to zero in this 801 specification. 803 U flag Buffer flag. Same as [RFC5568]. 805 P flag Proxy flag. Used to distinguish the message from that 806 defined in [RFC5568] and MUST be set in all new message 807 formats defined in this document when using this protocol 808 extension. 810 F flag Forwarding flag. Used to request to forward the packets 811 for the mobile node. 813 Reserved Same as [RFC5568]. 815 Code [RFC5568] defines this field and its values 0 and 1. In 816 this specification, with the P flag set, this field can 817 be set to zero by default or the following values: 819 2: Indicate the completion of forwarding 821 3: All available context transferred 823 Code value 3 is set when the transfer of all necessary 824 context information is completed with this message. This 825 Code value is used in both cases where the context 826 information is fragmented into several pieces and the 827 last fragment is contained in this message and where the 828 whole information is transferred in one piece. 830 Mobility options: 832 This field contains one or more mobility options, whose encoding and 833 formats are defined in [RFC3775]. 835 Required option 836 In order to uniquely identify the target mobile node, the 837 mobile node Identifier MUST be contained in the Mobile Node 838 Identifier Option. 840 The transferred context MUST be for one mobile node per message. In 841 addition, the NMAG can request necessary mobility options by the 842 Context Request Option defined in this document. 844 Context Request Option 846 This option MAY be present to request context information 847 typically by the NMAG to the PMAG in the NMAG-initiated fast 848 handover. 850 6.1.2. Handover Acknowledge (HAck) 852 This section defines extensions to the HAck message in[RFC5568]. The 853 format of the Message Data field in the Mobility Header is as 854 follows: 856 0 1 2 3 857 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 1 858 +-------------------------------+ 859 | Sequence # | 860 +-+-+-+---------+---------------+-------------------------------+ 861 |U|P|F|Reserved | Code | | 862 +-+-+-+---------+---------------+ | 863 | | 864 . . 865 . Mobility options . 866 . . 867 | | 868 +---------------------------------------------------------------+ 869 (Note:P=1) 871 IP Fields: 873 Source Address 875 Copied from the destination address of the 876 Handover Initiate message to which this message 877 is a response. 879 Destination Address 881 Copied from the source address of the Handover 882 Initiate message to which this message is a 883 response. 885 Message Data: 887 The usages of Sequence # and Reserved fields are exactly the same as 888 those in [RFC5568]. 890 U flag Same as defined in Section 6.1.1. 892 P flag Used to distinguish the message from that defined in 893 [RFC5568] and MUST be set in all new message formats 894 defined in this document when using this protocol 895 extension. 897 F flag Same as defined in Section 6.1.1. 899 Code 900 Code values 0 through 4 and 128 through 130 are defined 901 in [RFC5568]. In this specification, the meaning of Code 902 value 0 is modified, 128 through 130 are reused, and 5, 903 6, 131 and 132 are newly defined. 905 0: Handover Accepted or Successful 907 5: Context Transfer Accepted or Successful 909 6: All available Context Transferred 911 128: Handover Not Accepted, reason unspecified 913 129: Administratively prohibited 915 130: Insufficient resources 917 131: Requested Context Not Available 919 132: Forwarding Not Available 921 Mobility options: 923 This field contains one or more mobility options, whose encoding and 924 formats are defined in [RFC3775]. The mobility option that uniquely 925 identifies the target mobile node MUST be copied from the 926 corresponding HI message and the transferred context MUST be for one 927 mobile node per message. 929 Required option(s) All the context information requested by the 930 Context Request Option in the HI message SHOULD be present 931 in the HAck message. The other cases are described below. 933 In the case of the PMAG-initiated fast handover, when the PMAG sends 934 the HI message to the NMAG with the context information and the NMAG 935 successfully receives it, the NMAG returns the HAck message with Code 936 value 5. In the case of the NMAG-initiated fast handover, when the 937 NMAG sends the HI message to the PMAG with or without Context Request 938 Option, the PMAG returns the HAck message with the requested or 939 default context information (if any). If all available context 940 information is transferred, the PMAG sets the Code value in the HAck 941 message to 6. If more context information is available, the PMAG 942 sets the Code value in the HAck to 5 and the NMAG MAY send new HI 943 message(s) to retrieve the rest of the available context information. 944 If none of the requested context information is available, the PMAG 945 returns the HAck message with Code value 131 without any context 946 information. 948 6.2. Mobility Options 950 6.2.1. Context Request Option 952 This option is sent in the HI message to request context information 953 on the mobile node. If a default set of context information is 954 defined and always sufficient, this option is not used. This option 955 is more useful to retrieve additional or dynamically selected context 956 information. 958 Context Request Option is typically used for the reactive (NMAG- 959 initiated) fast handover mode to retrieve the context information 960 from the PMAG. When this option is included in the HI message, all 961 the requested context information SHOULD be included in the HAck 962 message in the corresponding mobility option(s) (e.g., HNP, LMAA or 963 MN LL-ID mobility options). 965 The default context information to request is the Home Network Prefix 966 Option. If the Mobile Node link-layer is available and used, the 967 Mobile Node Link-layer Identifier Option MUST also be requested. 969 0 1 2 3 970 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 1 971 +---------------+---------------+---------------+---------------+ 972 | Option-Type | Option-Length | Reserved | 973 +---------------+---------------+-------------------------------+ 974 | Req-type-1 | Req-length-1 | Req-type-2 | Req-length-2 | 975 +---------------------------------------------------------------+ 976 | Req-type-3 | Req-length-3 | Req-option-3 | 977 +---------------------------------------------------------------+ 978 | ... | 980 Option-Type TBD1 982 Option-Length The length in octets of this option, not including the 983 Option Type and Option Length fields. 985 Reserved This field is unused. It MUST be initialized to zero 986 by the sender and MUST be ignored by the receiver. 988 Req-type-n The type value for the n'th requested option. 990 Req-length-n The length of the n'th requested option excluding the 991 Req-type-n and Req-length-n fields. 993 Req-option-n The optional data to uniquely identify the requested 994 context for the n'th requested option. 996 In the case where there are only Req-type-n and Req-length-n fields, 997 the value of the Req-length-n is set to zero. If additional 998 information besides the Req-type-n is necessary to uniquely specify 999 the requested context, such information follows after the 1000 Req-length-n. For example, when the requested contexts start with 1001 the HNP Option (type=22), the MN Link-layer ID Option (type=25) and 1002 the Vendor-Specific Option (type=19), the required option format 1003 looks as follows: 1005 | ... | 1006 +---------------+---------------+---------------+---------------+ 1007 |Option-Type=CRO| Option-Length | Reserved | 1008 +---------------+---------------+---------------+---------------+ 1009 | Req-type-N=22 | Req-length-N=0| Req-type-N=25 | Req-length-N=0| 1010 +---------------+---------------+-------------------------------+ 1011 | Req-type-N=19 | Req-length-N=5| Vendor-ID | 1012 +-------------------------------+---------------+---------------+ 1013 | Vendor-ID | Sub-Type | | 1014 +-----------------------------------------------+ | 1015 | ... | 1017 The first two options can uniquely identify the requested contexts 1018 (i.e., the HNP and MN Link-layer ID) by the Req-type, so the Req- 1019 length is set to zero; however, the subsequent Vendor-Specific Option 1020 further needs the Vendor-ID and Sub-type to identify the requested 1021 context, so these parameters follow and the Req-length is set to 5. 1022 Note that the exact values in the Vendor-ID and Sub-Type follow 1023 [RFC5094]. 1025 6.2.2. Local Mobility Anchor Address (LMAA) Option 1027 This option is used to transfer the Local Mobility Anchor IPv6 1028 Address (LMAA) or its IPv4 Address (IPv4-LMAA), with which the mobile 1029 node is currently registered. The detailed definition of the LMAA is 1030 described in [RFC5213]. 1032 0 1 2 3 1033 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 1034 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1035 | Option-Type | Option-Length | Option-Code | Reserved | 1036 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1037 | Local Mobility Anchor Address ... | 1039 Option-Type TBD2 1041 Option-Length 18 or 6 1043 Option-Code 1045 0 Reserved 1047 1 IPv6 address of the local mobility anchor (LMAA) 1049 2 IPv4 address of the local mobility anchor (IPv4- 1050 LMAA) 1052 Reserved This field is unused. It MUST be initialized to zero 1053 by the sender and MUST be ignored by the receiver. 1055 Local Mobility Anchor Address 1056 If Option-Code is 1, the LMA IPv6 address (LMAA) is 1057 inserted. If Option-Code is 2, the LMA IPv4 address 1058 (IPv4-LMA) is inserted. 1060 6.2.3. Mobile Node Link-local Address Interface Identifier (MN LLA-IID) 1061 Option 1063 This option is used to transfer the interface identifier of the 1064 mobile node's IPv6 Link-local Address that is used in the P-AN. In 1065 deployments where the interface identifier is assigned by the 1066 network, or it is known to the network, this option is used to 1067 transfer this identifier from the PMAG to NMAG. 1069 0 1 2 3 1070 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 1071 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1072 | Option-Type | Option-Length | Reserved | 1073 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1074 | | 1075 + Interface Identifier + 1076 | | 1077 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1079 Option-Type TBD3 1081 Option-Length 10 1083 Reserved This field is unused. It MUST be initialized to zero 1084 by the sender and MUST be ignored by the receiver. 1086 Interface Identifier 1087 The Interface Identifier value used for the mobile 1088 node's IPv6 Link-local address in the P-AN. 1090 6.2.4. Home Network Prefix Option 1092 This option is used to transfer the home network prefix that is 1093 assigned to the mobile node in the P-AN. The Home Network Prefix 1094 Option defined in [RFC5213] is used for this. 1096 6.2.5. Link-local Address Option 1098 This option is used to transfer the link-local address of the PMAG 1099 (PMAG). The Link-local Address Option defined in [RFC5213] is used 1100 for this. 1102 6.2.6. GRE Key Option 1104 This option is used to transfer the GRE Key for the mobile node's 1105 data flow over the bi-directional tunnel between the PMAG and NMAG. 1106 The message format of this option follows the GRE Key Option defined 1107 in [GREKEY]. The GRE Key value uniquely identifies each flow and the 1108 sender of this option expects to receive packets of the flow from the 1109 peer AR with this value. 1111 6.2.7. IPv4 Address Option 1113 As described in Section 4.3, if the mobile node runs in IPv4-only 1114 mode or dual-stack mode, it requires IPv4 home address (IPv4-MN-HoA). 1115 This option is used to transfer the IPv4 home address if assigned on 1116 the previous link. The format of this option follows the IPv4 Home 1117 Address Request Option defined in [IPv4PMIPv6]. 1119 6.2.8. Vendor-Specific Mobility Option 1121 This option is used to transfer any other information defined in this 1122 document. The format and used values of this option follow the 1123 Vendor-Specific Mobility Option defined in [RFC5094]. 1125 7. Security Considerations 1127 Security issues for this document follow those for PMIPv6 [RFC5213] 1128 and FMIPv6 [RFC5568]. In PMIPv6, the MAG and local mobility anchor 1129 are assumed to share security associations. In FMIPv6, the access 1130 routers (i.e., the PMAG and NMAG in this document) are assumed to 1131 share security associations. 1133 The Handover Initiate (HI) and Handover Acknowledge (HAck) messages 1134 exchanged between the PMAG and NMAG MUST be protected using end-to- 1135 end security association(s) offering integrity and data origin 1136 authentication. The PMAG and the NMAG MUST implement IPsec [RFC4301] 1137 for protecting the HI and HAck messages. IPsec Encapsulating 1138 Security Payload (ESP) [RFC4303] in transport mode with mandatory 1139 integrity protection SHOULD be used for protecting the signaling 1140 messages. Confidentiality protection SHOULD be used if sensitive 1141 context related to the mobile node is transferred. 1143 IPsec ESP [RFC4303] in tunnel mode SHOULD be used to protect the 1144 mobile node's packets at the time of forwarding if the link between 1145 the PMAG and NMAG exposes the mobile node's packets to more threats 1146 than if they had followed their normal routed path. 1148 8. IANA Considerations 1150 This document defines new flags and status codes in the HI and HAck 1151 messages as well as three new mobility options. The Type values for 1152 these mobility options are assigned from the same numbering space as 1153 allocated for the other mobility options defined in [RFC3775]. Those 1154 for the flags and status codes are assigned from the corresponding 1155 numbering space defined in [RFC5568] and requested to be created as 1156 new tables in the IANA registry (marked with asterisks). New values 1157 for these registries can be allocated by Standards Action or IESG 1158 approval [RFC5226]. 1160 Mobility Options 1161 Value Description Reference 1162 ----- ------------------------------------- ------------- 1163 TBD1 Context Request Option Section 6.2.1 1164 TBD2 Local Mobility Anchor Address Option Section 6.2.2 1165 TBD3 Mobile Node Link-local Address 1166 Interface Identifier Option Section 6.2.3 1168 Handover Initiate Flags (*) 1169 Registration Procedures: Standards Action or IESG Approval 1170 Flag Value Description Reference 1171 ---- ----- ----------------------------------- ------------- 1172 S 0x80 Assigned Address Configuration flag [RFC5568] 1173 U 0x40 Buffer flag [RFC5568] 1174 P 0x20 Proxy flag Section 6.1.1 1175 F 0x10 Forwarding flag Section 6.1.1 1177 Handover Acknowledge Flags (*) 1178 Registration Procedures: Standards Action or IESG Approval 1179 Flag Value Description Reference 1180 ---- ----- ------------------------------- ------------- 1181 U 0x80 Buffer flag Section 6.1.2 1182 P 0x40 Proxy flag Section 6.1.2 1183 F 0x20 Forwarding flag Section 6.1.2 1185 Handover Initiate Status Codes (*) 1186 Registration Procedures: Standards Action or IESG Approval 1187 Code Description Reference 1188 ---- -------------------------------------- ------------- 1189 0 FBU with the PCoA as source IP address [RFC5568] 1190 1 FBU whose source IP address is not PCoA [RFC5568] 1191 2 Indicate the completion of forwarding Section 6.1.1 1192 3 All available context transferred Section 6.1.1 1194 4-255 Unassigned 1196 Handover Acknowledge Status Codes (*) 1197 Registration Procedures: Standards Action or IESG Approval 1198 Code Description Reference 1199 ---- --------------------------------------- ------------- 1200 0 Handover Accepted or Successful Section 6.1.2 1201 (with NCoA valid) [RFC5568] 1202 1 Handover Accepted, NCoA not valid [RFC5568] 1203 2 Handover Accepted, NCoA assigned [RFC5568] 1204 3 Handover Accepted, use PCoA [RFC5568] 1205 4 Message sent unsolicited [RFC5568] 1206 5 Context Transfer Accepted or Successful Section 6.1.2 1207 6 All available Context Transferred Section 6.1.2 1208 7-127 Unassigned 1209 128 Handover Not Accepted, reason unspecified [RFC5568] 1210 129 Administratively prohibited [RFC5568] 1211 130 Insufficient resources [RFC5568] 1212 131 Requested Context Not Available Section 6.1.2 1213 132 Forwarding Not Available Section 6.1.2 1214 133-255 Unassigned 1216 9. Acknowledgments 1218 The authors would like to specially thank Vijay Devarapalli and Sri 1219 Gundavelli for their thorough reviews of this document. 1221 The authors would also like to thank Charlie Perkins, Desire Oulai, 1222 Ahmad Muhanna, Giaretta Gerardo, Domagoj Premec, Marco Liebsch, Fan 1223 Zhao, Julien Laganier and Pierrick Seite for their passionate 1224 discussions in the working group mailing list. 1226 10. References 1228 10.1. Normative References 1230 [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., 1231 and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. 1233 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1234 Requirement Levels", BCP 14, RFC 2119, March 1997. 1236 [RFC5568] Koodli, R., "Mobile IPv6 Fast Handovers", RFC 5568, 1237 July 2009. 1239 [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support 1240 in IPv6", RFC 3775, June 2004. 1242 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 1243 Internet Protocol", RFC 4301, December 2005. 1245 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 1246 RFC 4303, December 2005. 1248 [RFC5094] Devarapalli, V., Patel, A., and K. Leung, "Mobile IPv6 1249 Vendor Specific Option", RFC 5094, December 2007. 1251 [IPv4PMIPv6] 1252 Wakikawa, R., Ed. and S. Gundavelli, "IPv4 Support for 1253 Proxy Mobile IPv6", 1254 draft-ietf-netlmm-pmip6-ipv4-support-18.txt, 1255 February 2010. 1257 [GREKEY] Muhanna, A., Ed., "GRE Key Option for Proxy Mobile IPv6", 1258 draft-ietf-netlmm-grekey-option-09.txt, May 2009. 1260 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1261 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 1262 May 2008. 1264 10.2. Informative References 1266 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 1267 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 1268 September 2007. 1270 [RFC4988] Koodli, R. and C. Perkins, "Mobile IPv4 Fast Handovers", 1271 RFC 4988, October 2007. 1273 Appendix A. Applicable Use Cases 1275 A.1. PMIPv6 Handoff Indication 1277 PMIPv6 [RFC5213] defines the Handoff Indicator Option and describes 1278 the type of the handoff and the values to set to the option. This 1279 document proposes one approach to determining the handoff type by the 1280 NMAG when the handoff of the mobile node is executed. 1282 According to [RFC5213], the following handoff types are defined: 1284 0) Reserved 1286 1) Attachment over a new interface 1288 2) Handoff between two different interfaces of the mobile node 1290 3) Handoff between mobile access gateways for the same interface 1292 4) Handoff state unknown 1294 5) Handoff state not changed (Re-registration) 1296 Assuming that there is a valid MN Link-layer Identifier (MN LL-ID), 1297 the following solution can be considered. When the NMAG receives the 1298 MN LL-ID from the PMAG in the MN LL-ID option via the HI or HAck 1299 message, the NMAG compares it with the new MN LL-ID that is obtained 1300 from the mobile node in the N-AN. If these two MN LL-IDs are the 1301 same, the handoff type falls into 3) and the Handoff Indicator value 1302 is set to 3. If these two MN LL-IDs are different, the handoff is 1303 likely to be 2) since the HI/HAck message exchange implies that this 1304 is a handoff not a multi-homing, therefore the Handoff Indicator 1305 value can be set to 2. If there is no HI/HAck exchange performed 1306 prior to the network attachment of the mobile node in the N-AN, the 1307 NMAG may infer that this is a multi-homing case and set the Handoff 1308 Indicator value to 1. In the case of re-registration, the MAG, to 1309 which the mobile node is attached, can determine if the handoff state 1310 is not changed, so the MAG can set the HI value to 5 without any 1311 additional information. If none of them can be assumed or there is 1312 no valid MN LL-ID available, the NMAG may set the value to 4. 1314 A.2. Local Routing 1316 Section 6.10.3 in [RFC5213] describes that if EnableMAGLocalRouting 1317 flag is set, when two mobile nodes are attached to one MAG, the 1318 traffic between them may be locally routed. If one mobile node moves 1319 from this MAG (PMAG) to another MAG (NMAG) and if the PMAG does not 1320 detect the mobile node's detachment, it will continue to forward 1321 packets locally forever. This situation is more likely to happen in 1322 the reactive fast handover with WLAN access, which does not have the 1323 capability to detect the detachment of the mobile node in a timely 1324 manner. PFMIPv6 can be applied to handle this case. When the mobile 1325 node attaches to the NMAG, the NMAG sends the HI message to the PMAG 1326 with the 'F' flag set, which makes the PMAG realize the detachment of 1327 the mobile node and establish the inter-MAG tunnel. The PMAG 1328 immediately stops the local routing and sends the packets for the 1329 mobile node to the NMAG via that tunnel, which are then delivered to 1330 the mobile node on the new link. 1332 Appendix B. Change Log 1334 Changes at -00 1336 * Added separate sections for MH and ICMP. 1338 * Clarified usage of HNP and IPv4-MN-HoA throughout the document. 1340 * Added IANA Considerations. 1342 * Added section on Other Considerations, including operation of 1343 uplink packets when using link-layer addresses, multiple 1344 interface usage and transmission of RA to withdraw HNP in the 1345 event of failure of PMIP6 registration. 1347 * Revised Security Considerations. 1349 Changes from -00 to -01 1351 * Removed ICMPv6-based message format. 1353 * Clarified HI/HAck exchange in the predictive mode (step (e) in 1354 Figure 2). 1356 * Clarified information retrieval about the PMAG in the reactive 1357 mode. 1359 * Removed the extension to the GRE Key Option. 1361 * Clarified the handoff type considerations in Appendix A. 1363 * Home Network Prefix Option, Link-local Address Option and 1364 Vendor-Specific Mobility Option are added. 1366 Changes from -01 to -02 1368 * Aligned HI/HAck message formats with 1369 draft-ietf-mipshop-rfc5268bis-00.txt. 1371 * Revised Section 8 removing the request for the type assignment 1372 of HI/HAck Mobility Headers. 1374 Changes from -02 to -03 1376 * Updated HI/HAck message formats according to 1377 draft-ietf-mipshop-rfc5268bis-01.txt. 1379 * Cleaned up Figure 2 and Figure 3. 1381 * Moved PMIP domain boundary crossing situation in Section 4.1 to 1382 Appendix A.3. 1384 * Removed the alternative protocol operation with an unsolicited 1385 HAck from Section 4.1. 1387 * Modified Code values in the HAck message in order to avoid 1388 collision with those in draft-ietf-mipshop-rfc5268bis-01.txt. 1390 * Clarified the usage scenarios of Context Request Option. 1392 * Modified the description of Code values in the HAck message. 1394 * Changed the container for the IPv4-LMAA from IPv4 Address 1395 option to the LMAA option. 1397 * Made Confidentiality protection "SHOULD" for context transfer. 1399 Changes from -03 to -04 1401 * Added more explanations about MIPv6, FMIPv6 and PMIPv6 in 1402 Abstract. 1404 * Moved Figure 1 to Section 4. 1406 * More clearly indicated the FMIPv6 messages that are not 1407 applicable in the PMIPv6 context. 1409 * Mandated the support of IP Sec on the PMAG and NMAG in order to 1410 protect signaling and user packets and the context information. 1412 * Added a new section for the inter-AR tunneling operation 1413 (Section 4.2). 1415 * Added descriptions about the encapsulation type in Sections 4.1 1416 and 4.3. 1418 * Added a description about buffering requirements on the MAG in 1419 Section 4.1. 1421 * Added a description about the timing of L2 and L3 connection 1422 establishments in Section 4.1. 1424 * Added a new section for PMIPv6-related fast handover issues 1425 (Section 5) and a description about preferable behaviors of the 1426 mobile node and MAG to reduce packet loss. 1428 * Added Acknowledgments section (Section 9). 1430 * Added a new section for local routing in Appendix (A.2). 1432 Changes from -04 to -05 1434 * Fixed Figure 2 (step (i)). 1436 * Defined the Mobile Network Interface Identifier (MN-IID) 1437 mobility option in Section 6.2.4 (swapped with old Section 1438 6.2.5), and added it to IANA considerations (Section 8). 1440 * Changed from SHOULD to MUST regarding the inclusion of the 1441 MN-ID, MN-HNP, MN-IID and the LMAA options in the HI message 1442 (step (c) in Section 4.1). 1444 * The optional behavior of the NMAG that allows it to send uplink 1445 packets directly to the local mobility anchor before the PBU/ 1446 PBA exchange was removed from section 4.2 (as out of scope). 1448 * In Section A.3, the description about the HA address assignment 1449 from the NAR to the mobile node was removed (as out of scope). 1451 Changes from -05 to -06 1453 * Added 'P' flag in the HI and Hack messages to distinguish them 1454 from those in FMIPv6. 1456 * Made editorial corrections in Section 2 (Introduction), Section 1457 3 (Terminology), Section 4 (Protocol Overview) and Section 4.2 1458 (Inter-AR Tunneling Operation). 1460 * Added a description on how forwarded packets should be handled 1461 in the access network at step (f) in Section 4.1. 1463 * Added all types of encapsulation methods that should be 1464 supported in Section 4.1. 1466 * Revised the Code values for the HI message in Section 6.1.1. 1468 * Revised the Code values for the HAck message in Section 6.1.2 1469 and added a description of its usage at step (d) of the 1470 reactive handover mode in Section 4.1. 1472 * Removed the definition of the IP Address Option in Section 1473 6.2.3 and moved to Section 6.2.7, which currently refers to the 1474 IPv4 Home Address Option defined by RFC5555. Revised the IANA 1475 Consideration section accordingly. 1477 * Removed the Option-Code from the Mobile Node Identifier (MN 1478 IID) Option. 1480 * Removed Appendix A.3 (Handling of PMIPv6/MIPv6 switching). 1482 Changes from -06 to -07 1484 * Added explanations about defining and setting the 'P' flag for 1485 the HI and Hack messages in Sections 4 and 4.1. 1487 * Corrected the references for the encapsulation types in Section 1488 4.1. 1490 * Modified the Code values for the HI message in Section 6.1.1 to 1491 avoid overlapping with those in 1492 draft-ietf-mipshop-rfc5268bis-01.txt. 1494 * Modified the reference for the IPv4 Address Option from RFC5555 1495 to [IPv4PMIPv6] in Section 6.2.7. 1497 Changes from -07 to -08 1499 * Corrected the reference for the TLV-header UDP encapsulation in 1500 Section 4.1. 1502 * Updated the version number of the reference document 1503 [IPv4PMIPv6] and the option name defined by that document in 1504 Section 6.2.7. 1506 Changes from -08 to -09 1508 * Added a paragraph at the beginning of Section 4 describing the 1509 assumption related to the lower layer signaling. 1511 * Added a new section on the manageability considerations in 1512 Section 5 describing the configurations on the network and the 1513 mobile node assumed in this document. 1515 * Modified the assumed configuration of the MAG regarding its 1516 link-layer address in Section 5 (Section 5.2 in version -09). 1518 * Specified the requested option to identify the target MN for 1519 the inter-AR tunneling in Section 6.1.1. 1521 * Specified the default context information in the Context 1522 Request Option in Section 6.2.1. 1524 Changes from -09 to -10 1526 * Revised the document based on the comments from TSV-DIR, SEC- 1527 DIR, OPS-DIR and GEN-ART. 1529 + Split the abstract section in half for readability. 1531 + Added the definition of Localized Mobility Anchor (local 1532 mobility anchor) in Section 3. 1534 + Added the purpose of this document at the beginning of 1535 Section 4 to make the paragraph more complete. 1537 + Revised the third paragraph of the Security Consideration 1538 section for more precise expression. 1540 + Moved the description about the requirement to set the 'P' 1541 flag in HI/HAck to Sections 6.1.1 and 6.1.2. Also, noted 1542 the 'P' flag setting below the message formats. 1544 + Described the both 'P' and 'F' flags as newly defined ones 1545 in Section 4. 1547 + Clarified the usage of the Context Request Option if a 1548 default set of context information is defined in Section 1549 6.2.1 (changed from "not mandatory" to "not used"). 1551 + Modified the identifier for the interface on the MN to the 1552 MN's link-layer ID (MN LL-ID). 1554 + Corrected the local routing operation of the PMAG in 1555 Appendix A.2. 1557 * Revised the descriptions about the encapsulation mechanism for 1558 the inter-MAG tunnel in Section 4.2 and other related parts for 1559 clarification. 1561 * Also listed the new flags and status codes for the HI/HAck 1562 messages in the IANA Considerations section. 1564 * Elaborated on the example use of the Context Request Option in 1565 Section 6.2.1. 1567 Changes from -10 to -11 1569 * Changed the term "MN Interface Identifier (MN-IID) option" to 1570 "MN Link-local Address Interface Identifier (MN LLA-IID) 1571 option" in Section 6.2.3. Its usage is valid only when the 1572 network assigns the interface identifier. 1574 * Revised the description of the neighbor cache entry in Section 1575 4.1 to include the MN LLA-IID. 1577 Changes from -11 to -12 1579 * Changed the term "HO-Initiate" to "Handover indication". 1581 * Added the handover trigger from the PMAG to the mobile node 1582 ("Handover command") to clarify the timing of handover in 1583 Figure 2. 1585 * Revised IANA Considerations to include all values that are 1586 defined in RFC5568, but not in the IANA Registry yet. 1588 Changes from -12 to -13 1590 * Editorial corrections. 1592 Authors' Addresses 1594 Hidetoshi Yokota 1595 KDDI Lab 1596 2-1-15 Ohara, Fujimino 1597 Saitama, 356-8502 1598 Japan 1600 Email: yokota@kddilabs.jp 1602 Kuntal Chowdhury 1603 Cisco Systems 1604 30 International Place 1605 Tewksbury, MA 01876 1606 USA 1608 Email: kchowdhury@cisco.com 1610 Rajeev Koodli 1611 Cisco Systems 1612 30 International Place 1613 Tewksbury, MA 01876 1614 USA 1616 Email: rkoodli@cisco.com 1618 Basavaraj Patil 1619 Nokia 1620 6000 Connection Drive 1621 Irving, TX 75039 1622 USA 1624 Email: basavaraj.patil@nokia.com 1626 Frank Xia 1627 Huawei USA 1628 1700 Alma Dr. Suite 500 1629 Plano, TX 75075 1630 USA 1632 Email: xiayangsong@huawei.com