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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 360, but not defined == Missing Reference: 'AR-Info' is mentioned on line 360, 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: November 15, 2010 R. Koodli 6 Cisco Systems 7 B. Patil 8 Nokia 9 F. Xia 10 Huawei USA 11 May 14, 2010 13 Fast Handovers for Proxy Mobile IPv6 14 draft-ietf-mipshop-pfmipv6-14.txt 16 Abstract 18 Mobile IPv6 (MIPv6) [RFC3775] provides a mobile node with IP mobility 19 when it performs a handover from one access router to another and 20 fast handovers for Mobile IPv6 (FMIPv6) [RFC5568] are specified to 21 enhance the handover performance in terms of latency and packet loss. 22 While MIPv6 (and FMIPv6 as well) requires the participation of the 23 mobile node in the mobility-related signaling, Proxy Mobile IPv6 24 (PMIPv6) [RFC5213] provides IP mobility to nodes that either have or 25 do not have MIPv6 functionality without such involvement. 26 Nevertheless, the basic performance of PMIPv6 in terms of handover 27 latency and packet loss is considered not any different from that of 28 MIPv6. 30 When the fast handover is considered in such an environment, several 31 modifications are needed to FMIPv6 to adapt to the network-based 32 mobility management. This document specifies the usage of Fast 33 Mobile IPv6 (FMIPv6) when Proxy Mobile IPv6 is used as the mobility 34 management protocol. Necessary extensions are specified for FMIPv6 35 to support the scenario when the mobile node does not have IP 36 mobility functionality and hence is not involved with either MIPv6 or 37 FMIPv6 operations. 39 Status of this Memo 41 This Internet-Draft is submitted in full conformance with the 42 provisions of BCP 78 and BCP 79. 44 Internet-Drafts are working documents of the Internet Engineering 45 Task Force (IETF). Note that other groups may also distribute 46 working documents as Internet-Drafts. The list of current Internet- 47 Drafts is at http://datatracker.ietf.org/drafts/current/. 49 Internet-Drafts are draft documents valid for a maximum of six months 50 and may be updated, replaced, or obsoleted by other documents at any 51 time. It is inappropriate to use Internet-Drafts as reference 52 material or to cite them other than as "work in progress." 54 This Internet-Draft will expire on November 15, 2010. 56 Copyright Notice 58 Copyright (c) 2010 IETF Trust and the persons identified as the 59 document authors. All rights reserved. 61 This document is subject to BCP 78 and the IETF Trust's Legal 62 Provisions Relating to IETF Documents 63 (http://trustee.ietf.org/license-info) in effect on the date of 64 publication of this document. Please review these documents 65 carefully, as they describe your rights and restrictions with respect 66 to this document. Code Components extracted from this document must 67 include Simplified BSD License text as described in Section 4.e of 68 the Trust Legal Provisions and are provided without warranty as 69 described in the Simplified BSD License. 71 This document may contain material from IETF Documents or IETF 72 Contributions published or made publicly available before November 73 10, 2008. The person(s) controlling the copyright in some of this 74 material may not have granted the IETF Trust the right to allow 75 modifications of such material outside the IETF Standards Process. 76 Without obtaining an adequate license from the person(s) controlling 77 the copyright in such materials, this document may not be modified 78 outside the IETF Standards Process, and derivative works of it may 79 not be created outside the IETF Standards Process, except to format 80 it for publication as an RFC or to translate it into languages other 81 than English. 83 Table of Contents 85 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 4 86 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 87 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 88 4. Proxy-based FMIPv6 Protocol Overview . . . . . . . . . . . . . 7 89 4.1. Protocol Operation . . . . . . . . . . . . . . . . . . . . 8 90 4.2. Inter-AR Tunneling Operation . . . . . . . . . . . . . . . 15 91 4.3. IPv4 Support Considerations . . . . . . . . . . . . . . . 17 92 5. PMIPv6-related Fast Handover Issues . . . . . . . . . . . . . 18 93 5.1. Manageability Considerations . . . . . . . . . . . . . . . 18 94 5.2. Expedited Packet Transmission . . . . . . . . . . . . . . 18 95 6. Message Formats . . . . . . . . . . . . . . . . . . . . . . . 20 96 6.1. Mobility Header . . . . . . . . . . . . . . . . . . . . . 20 97 6.1.1. Handover Initiate (HI) . . . . . . . . . . . . . . . . 20 98 6.1.2. Handover Acknowledge (HAck) . . . . . . . . . . . . . 22 99 6.2. Mobility Options . . . . . . . . . . . . . . . . . . . . . 24 100 6.2.1. Context Request Option . . . . . . . . . . . . . . . . 24 101 6.2.2. Local Mobility Anchor Address (LMAA) Option . . . . . 25 102 6.2.3. Mobile Node Link-local Address Interface 103 Identifier (MN LLA-IID) Option . . . . . . . . . . . . 26 104 6.2.4. Home Network Prefix Option . . . . . . . . . . . . . . 27 105 6.2.5. Link-local Address Option . . . . . . . . . . . . . . 27 106 6.2.6. GRE Key Option . . . . . . . . . . . . . . . . . . . . 27 107 6.2.7. IPv4 Address Option . . . . . . . . . . . . . . . . . 27 108 6.2.8. Vendor-Specific Mobility Option . . . . . . . . . . . 27 109 7. Security Considerations . . . . . . . . . . . . . . . . . . . 28 110 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29 111 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 31 112 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 32 113 10.1. Normative References . . . . . . . . . . . . . . . . . . . 32 114 10.2. Informative References . . . . . . . . . . . . . . . . . . 32 115 Appendix A. Applicable Use Cases . . . . . . . . . . . . . . . . 33 116 A.1. PMIPv6 Handoff Indication . . . . . . . . . . . . . . . . 33 117 A.2. Local Routing . . . . . . . . . . . . . . . . . . . . . . 33 118 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 35 119 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 41 121 1. Requirements notation 123 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 124 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 125 document are to be interpreted as described in [RFC2119]. 127 2. Introduction 129 Proxy Mobile IPv6 (PMIPv6) [RFC5213] provides IP mobility to a mobile 130 node that does not support Mobile IPv6 [RFC3775] mobile node 131 functionality. A proxy agent in the network performs the mobility 132 management signaling on behalf of the mobile node. This model 133 transparently provides mobility for nodes within a PMIPv6 domain. 134 Nevertheless, the basic performance of PMIPv6 in terms of handover 135 latency and packet loss is considered not any different from that of 136 Mobile IPv6. 138 Fast Handovers for Mobile IPv6 (FMIPv6) [RFC5568] describes the 139 protocol to reduce the handover latency for Mobile IPv6 by allowing a 140 mobile node to send packets as soon as it detects a new subnet link 141 and by delivering packets to the mobile node as soon as its 142 attachment is detected by the new access router. This document 143 extends FMIPv6 for Proxy MIPv6 operation to minimize handover delay 144 and packet loss as well as to transfer network-resident context for a 145 PMIPv6 handover. [RFC5568] is normative for this document, except 146 where this document specifies new or revised 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, this 213 document specifies a bi-directional tunnel between the Previous MAG 214 (PMAG) and the New MAG (NMAG) to tunnel packets meant for the mobile 215 node. In order to enable the NMAG to send the Proxy Binding Update 216 (PBU), the Handover Initiate (HI) and Handover Acknowledge (HAck) 217 messages in [RFC5568] are extended for context transfer, in which 218 parameters such as mobile node's Network Access Identifier (NAI), 219 Home Network Prefix (HNP), IPv4 Home Address, are transferred from 220 the PMAG. New flags 'P' and 'F' are defined for the HI and HAck 221 messages to distinguish from those in [RFC5568] and to request packet 222 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. A MAG that receives a RtSolPr or 240 FBU message from a mobile node SHOULD behave as if they do not 241 implement FMIPv6 as defined in [RFC5568] at all, continuing to 242 operate according to this specification within the network, or 243 alternatively, start serving that particular mobile node as specified 244 in [RFC5568]. 246 +----------+ 247 | LMA | 248 | | 249 +----------+ 250 / \ 251 / \ 252 / \ 253 +........../..+ +..\..........+ 254 . +-------+-+ .______. +-+-------+ . 255 . | PMAG |()_______)| NMAG | . 256 . | (PAR) | . . | (NAR) | . 257 . +----+----+ . . +----+----+ . 258 . | . . | . 259 . ___|___ . . ___|___ . 260 . / \ . . / \ . 261 . ( P-AN ) . . ( N-AN ) . 262 . \_______/ . . \_______/ . 263 . | . . | . 264 . +----+ . . +----+ . 265 . | MN | ----------> | MN | . 266 . +----+ . . +----+ . 267 +.............+ +.............+ 269 Figure 1: Reference network for fast handover 271 4.1. Protocol Operation 273 There are two modes of operation in FMIPv6 [RFC5568]. In the 274 predictive mode of fast handover, a bi-directional tunnel between the 275 PMAG (PAR) and NMAG (NAR) is established prior to the mobile node's 276 attachment to the NMAG. In the reactive mode, this tunnel 277 establishment takes place after the mobile node attaches to the NMAG. 278 In order to alleviate the packet loss during a mobile node's handover 279 (especially when the mobile node is detached from both links), the 280 downlink packets for the mobile node need to be buffered either at 281 the PMAG or NMAG, depending on when the packet forwarding is 282 performed. It is hence REQUIRED that all MAGs have the capability 283 and enough resources to buffer packets for the mobile nodes 284 accommodated by them. The buffer size to be prepared and the rate at 285 which buffered packets are drained are addressed in Section 5.4 of 286 [RFC5568]. Note that the protocol operation specified in the 287 document is transparent to the local mobility anchor (LMA), hence 288 there is no new functional requirement or change on the LMA. 290 Unlike MIPv6, the mobile node in the PMIPv6 domain is not involved 291 with IP mobility signaling; therefore, in order for the predictive 292 fast handover to work effectively, it is REQUIRED that the mobile 293 node is capable of reporting lower-layer information to the AN at a 294 short enough interval, and the AN is capable of sending the Handover 295 indication to the PMAG at an appropriate timing. The sequence of 296 events for the predictive fast handover are illustrated in Figure 2. 298 PMAG NMAG 299 MN P-AN N-AN (PAR) (NAR) LMA 300 | | | | | | 301 (a) |--Report-->| | | | | 302 | | | | | | 303 | | Handover | | | 304 (b) | |------indication------>| | | 305 | | | | | | 306 | | | | | | 307 (c) | | | |----HI---->| | 308 | | | | | | 309 | | | | | | 310 (d) | | | |<---HAck---| | 311 | | | | | | 312 | | | | | | 313 | | | |HI/HAck(optional) | 314 (e) | | | |<- - - - ->| | 315 | | | #=|<===================| 316 (f) | | | #====DL data=>| | 317 | Handover | Handover | | | 318 (g) |<-command--|<------command---------| | | 319 ~~~ | | | | | 320 ~~~ | | | | | 321 | MN-AN connection | AN-MAG connection | | 322 (h) |<---establishment---->|<----establishment----->| | 323 | | | (substitute for UNA) | | 324 | | | | | | 325 (i) |<==================DL data=====================| | 326 | | | | | | 327 (j) |===================UL data====================>|=# | 328 | | | #=|<============# | 329 | | | #=====================>| 330 / | | | | | | \ 331 |(k) | | | | |--PBU-->| | 332 | | | | | | | | 333 |(l) | | | | |<--PBA--| | 334 | |<==================DL data=====================|<=======| | 335 | | | | | | | | 336 \ |===================UL data====================>|=======>| / 337 Figure 2: Predictive fast handover for PMIPv6 (PMAG initiated) 339 The detailed descriptions are as follows: 341 (a) The mobile node detects that a handover is imminent and reports 342 the identifier of itself (MN ID) and the New Access Point 343 Identifier (New AP ID) [RFC5568] to which the mobile node is 344 most likely to move. The MN ID could be the NAI, Link-layer 345 address, or any other suitable identifier, but the MAG SHOULD be 346 able to map any access specific identifier to the NAI as the MN 347 ID. In some cases, the previous access network (P-AN) will 348 determine the New AP ID for the mobile node. This step is 349 access technology specific and details are outside the scope of 350 this document. 352 (b) The previous access network, to which the mobile node is 353 currently attached, indicates the handover of the mobile node to 354 the previous mobile access gateway (PMAG), with the MN ID and 355 New AP ID. Detailed definition and specification of this 356 message are outside the scope of this document. 358 (c) The previous MAG derives the new mobile access gateway (NMAG) 359 from the New AP ID, which is a similar process to that of 360 constructing an [AP ID, AR-Info] tuple in [RFC5568]. The 361 previous MAG then sends the Handover Initiate (HI) message to 362 the new MAG. The HI message MUST have the P flag set and 363 include the MN ID, the HNP(s) and the address of the local 364 mobility anchor that is currently serving the mobile node. If 365 there is a valid (non-zero) MN Link-layer Identifier (MN LL-ID), 366 that information MUST also be included. With some link layers, 367 the MN Link-local Address IID (MN LLA-IID) can also be included 368 (see Section 6.2.3). 370 (d) The new MAG sends the Handover Acknowledge (HAck) message back 371 to the previous MAG with the P flag set. 373 (e) If it is preferred that the timing of buffering or forwarding 374 should be later than step (c), the new MAG MAY optionally 375 request the previous MAG at a later and appropriate time to 376 buffer or forward packets by setting U flag [RFC5568] or F flag 377 in the HI message, respectively. 379 (f) If the F flag is set in the previous step, a bi-directional 380 tunnel is established between the previous MAG and new MAG and 381 packets destined for the mobile node are forwarded from the 382 previous MAG to the new MAG over this tunnel. After 383 decapsulation, those packets MAY be buffered at the new MAG. If 384 the connection between the new access network and new MAG has 385 already been established, those packets MAY be forwarded towards 386 the new access network, which then becomes responsible for them 387 (e.g., buffering or delivering depending on the condition of the 388 mobile node's attachment); this is access technology specific. 390 (g) When handover is ready on the network side, the mobile node is 391 triggered to perform handover to the new access network. This 392 step is access technology specific and details are outside the 393 scope of this document. 395 (h) The mobile node establishes a physical link connection with the 396 new access network (e.g., radio channel assignment), which in 397 turn triggers the establishment of a link-layer connection 398 between the new access network and new MAG if not yet 399 established. An IP layer connection setup may be performed at 400 this time (e.g., PPP IPv6CP) or at a later time (e.g., stateful 401 or stateless auto address configuration). This step can be a 402 substitute for the Unsolicited Neighbor Advertisement (UNA) in 403 [RFC5568]. If the new MAG acquires a valid new MN LL-ID via the 404 new access network and a valid old MN LL-ID from the previous 405 MAG at step (c), these IDs SHOULD be compared to determine 406 whether the same interface is used before and after handover. 407 When the connection between the mobile node and new MAG is PPP 408 and the same interface is used for the handover, the new MAG 409 SHOULD confirm that the same interface identifier is used for 410 the mobile node's link-local address (this is transferred from 411 previous MAG using the MN LLA-IID option at step (c), and sent 412 to the mobile node during the Configure-Request/Ack exchange). 414 (i) The new MAG starts to forward packets destined for the mobile 415 node via the new access network. 417 (j) The uplink packets from the mobile node are sent to the new MAG 418 via the new access network and the new MAG forwards them to the 419 previous MAG. The previous MAG then sends the packets to the 420 local mobility anchor that is currently serving the mobile node. 422 (k) The new MAG sends the Proxy Binding Update (PBU) to the local 423 mobility anchor, whose address is provided in (c). Steps (k) 424 and (l) are not part of the fast handover procedure, but shown 425 for reference. 427 (l) The local mobility anchor sends back the Proxy Binding 428 Acknowledgment (PBA) to the new MAG. From this time on, the 429 packets to/from the mobile node go through the new MAG instead 430 of the previous MAG. 432 According to Section 4 of [RFC5568], the previous MAG establishes a 433 binding between the Previous Care-of Address (PCoA) and New Care-of 434 Address (NCoA) to forward packets for the mobile node to the new MAG, 435 and the new MAG creates a proxy neighbor cache entry to receive those 436 packets for the NCoA before the mobile node arrives. In the case of 437 PMIPv6, however, the only address that is used by the mobile node is 438 MN-HoA (Mobile Node's Home Address), so the PMAG forwards mobile 439 node's packets to the NMAG instead of the NCoA. The NMAG then simply 440 decapsulates those packets and delivers them to the mobile node. 441 FMIPv4 [RFC4988] specifies forwarding when the mobile node uses the 442 home address as its on-link address rather than the care-of address. 443 The usage in PMIPv6 is similar to that in FMIPv4, where the 444 address(es) used by the mobile node is/are based on its HNP(s). 445 Since the NMAG can obtain the Link-layer address (MN LL-ID) and 446 HNP(s) via the HI message (also the interface identifier of the 447 mobile node's link-local address (MN LLA-ID) if available), it can 448 create a neighbor cache entry for the Link-local Address and the 449 routes for the whole HNP(s) even before the mobile node performs 450 Neighbor Discovery. For the uplink packets from the mobile node 451 after handover in (j), the NMAG forwards the packets to the PMAG 452 through the tunnel established in step (f). The PMAG then 453 decapsulates and sends them to the local mobility anchor. 455 The timing of the context transfer and that of packet forwarding may 456 be different. Thus, a new flag 'F' and Option Code values for it in 457 the HI and HAck messages are defined to request forwarding. To 458 request buffering, 'U' flag has already been defined in [RFC5568]. 459 If the PMAG receives the HI message with the F flag set, it starts 460 forwarding packets for the mobile node. The HI message with the U 461 flag set MAY be sent earlier if the timing of buffering is different 462 from that of forwarding. If packet forwarding is completed, the PMAG 463 MAY send the HI message with the F flag set and the Option Code value 464 being 2. By this message, the ARs on both ends can tear down the 465 forwarding tunnel synchronously. 467 The IP addresses in the headers of those user packets are summarized 468 below: 470 In Step (f), 472 Inner source address: IP address of the correspondent node 474 Inner destination address: HNP or Mobile Node's IPv4 Home 475 Address (IPv4-MN-HoA) 477 Outer source address: IP address of the PMAG 478 Outer destination address: IP address of the NMAG 480 In Step (i), 482 Source address: IP address of the correspondent node 484 Destination address: HNP or IPv4-MN-HoA 486 In Step (j), 488 - from the mobile node to the NMAG, 490 Source address: HNP or IPv4-MN-HoA 492 Destination address: IP address of the correspondent node 494 - from the NMAG to the PMAG, 496 Inner source address: HNP or IPv4-MN-HoA 498 Inner destination address: IP address of the correspondent node 500 Outer source address: IP address of the NMAG 502 Outer destination address: IP address of the PMAG 504 - from the PMAG to the LMA, 506 Inner source address: HNP or IPv4-MN-HoA 508 Inner destination address: IP address of the correspondent node 510 Outer source address: IP address of the PMAG 512 Outer destination address: IP address of the LMA 514 In the case of the reactive handover for PMIPv6, since the mobile 515 node does not send either the FBU or UNA, it would be more natural 516 that the NMAG sends the HI to the PMAG after the mobile node has 517 moved to the new link. The NMAG then needs to obtain the information 518 of the PMAG beforehand. Such information could be provided, for 519 example, by the mobile node sending the AP-ID on the old link and/or 520 by the lower-layer procedures between the P-AN and N-AN. The exact 521 method is not specified in this document. Figure 3 illustrates the 522 reactive fast handover procedures for PMIPv6, where the bi- 523 directional tunnel establishment is initiated by the NMAG. 525 PMAG NMAG 526 MN P-AN N-AN (PAR) (NAR) LMA 527 | | | | | | 528 (a) ~~~ | | | | | 529 ~~~ | | | | | 530 | MN-AN connection | AN-MAG connection | | 531 (b) |<--establishment-->|<-------establishment------>| | 532 | | |(substitute for UNA and FBU)| | 533 | | | | | | 534 | | | | | | 535 (c) | | | |<-----HI-------| | 536 | | | | | | 537 | | | | | | 538 (d) | | | |-----HAck----->| | 539 | | | | | | 540 | | | | | | 541 (e) | | | #=|<=======================| 542 | | | #================>|=# | 543 |<====================DL data======================# | 544 | | | | | | 545 (f) |=====================UL data===================>|=# | 546 | | | #=|<================# | 547 | | | #=========================>| 548 | | | | | | 549 / | | | | | | \ 550 |(g) | | | | |--PBU-->| | 551 | | | | | | | | 552 |(h) | | | | |<--PBA--| | 553 | |<====================DL data====================|<=======| | 554 | | | | | | | | 555 \ |=====================UL data===================>|=======>| / 557 Figure 3: Reactive fast handover for PMIPv6 (NMAG initiated) 559 The detailed descriptions are as follows: 561 (a) The mobile node undergoes handover from the previous access 562 network to the new access network. 564 (b) The mobile node establishes a connection (e.g., radio channel) 565 with the new access network, which triggers the establishment of 566 the connection between the new access network and new MAG. The 567 MN ID is transferred to the new MAG at this step for the 568 subsequent procedures. The AP-ID on the old link (Old AP ID), 569 which will be provided by either the mobile node or the new 570 access network, is also transferred to the new MAG to help 571 identify the previous MAG on the new link. This can be regarded 572 as a substitute for the UNA and FBU. 574 (c) The new MAG sends the HI to the previous MAG. The HI message 575 MUST have the P flag set and include the MN ID. The Context 576 Request Option MAY be included to request additional context 577 information on the mobile node to the previous MAG. 579 (d) The previous MAG sends the HAck back to the new MAG with the P 580 flag set. The HAck message MUST include the HNP(s) and/or IPv4- 581 MN-HoA that is corresponding to the MN ID in the HI message and 582 SHOULD include the MN LL-ID, only if it is valid (non zero), and 583 the local mobility anchor address that is currently serving the 584 mobile node. The context information requested by the new MAG 585 MUST be included. If the requested context is not available for 586 some reason, the previous MAG MUST return the HAck with the Code 587 value 131. If the F flag is set in the HI at step (c) and 588 forwarding is nevertheless not executable for some reason, the 589 previous MAG MUST return the HAck with the Code value 132. 591 (e) If the F flag in the HI is set at step (c), a bi-directional 592 tunnel is established between the previous MAG and new MAG and 593 packets destined for the mobile node are forwarded from the 594 previous MAG to the new MAG over this tunnel. After 595 decapsulation, those packets are delivered to the mobile node 596 via the new access network. 598 (f) The uplink packets from the mobile node are sent to the new MAG 599 via the new access network and the new MAG forwards them to the 600 previous MAG. The previous MAG then sends the packets to the 601 local mobility anchor that is currently serving the mobile node. 603 Steps (g)-(h) are the same as (k)-(l) in the predictive fast handover 604 procedures. 606 In step (c), the IP address of the PMAG needs to be resolved by the 607 NMAG to send the HI to the PMAG. This information may come from the 608 N-AN or some database that the NMAG can access. 610 4.2. Inter-AR Tunneling Operation 612 When the PMAG (PAR) or NMAG (NAR), depending on the fast handover 613 mode, receives the HI message with the F flag set, it prepares to 614 send/receive the mobile node's packets to/from the other MAG and 615 returns the HAck message with the same sequence number. The both 616 MAGs SHOULD support the following encapsulation modes for the user 617 packets, which are also defined for the tunnel between the local 618 mobility anchor and MAG: 620 o IPv4-or-IPv6-over-IPv6 [IPv4PMIPv6] 622 o IPv4-or-IPv6-over-IPv4 [IPv4PMIPv6] 624 o IPv4-or-IPv6-over-IPv4-UDP [IPv4PMIPv6] 626 o TLV-header UDP tunneling [GREKEY] 628 o GRE tunneling with or without GRE key(s) [GREKEY] 630 The PMAG and the NMAG MUST use the same tunneling mechanism for the 631 data traffic tunneled between them. The encapsulation mode to be 632 employed SHOULD be configurable. It is RECOMMENDED that: 634 1. As the default behavior, the inter-MAG tunnel uses the same 635 encapsulation mechanism as that for the PMIPv6 tunnel between the 636 local mobility anchor and the MAGs. The PMAG and NMAG 637 automatically start using the same encapsulation mechanism 638 without a need for a special configuration on the MAGs or a 639 dynamic tunneling mechanism negotiation between them. 641 2. Configuration on the MAGs can override the default mechanism 642 specified in #1 above. The PMAG and NMAG MUST be configured with 643 the same mechanism and this configuration is most likely to be 644 uniform throughout the PMIPv6 domain. If the packets on the 645 PMIPv6 tunnel cannot be uniquely mapped on to the configured 646 inter-MAG tunnel, this scenario is not applicable and scenario #3 647 below SHOULD directly be applied. 649 3. An implicit or explicit tunnel negotiation mechanism between the 650 MAGs can override the default mechanism specified in #1 above. 651 The employed tunnel negotiation mechanism is outside the scope of 652 this document. 654 The necessary information MUST be transferred in the HI/HAck messages 655 to distinguish mobile node's packets for forwarding in advance or at 656 this time. Such information includes the HNP(s) (or IPv4-MN-HoA) 657 and/or GRE key(s). In the case of GRE tunneling with GRE keys being 658 used, for each mobility session, the NMAG selects the GRE key for the 659 downlink packets and the PMAG selects the GRE key for the uplink 660 packets. These GRE keys are exchanged between the PMAG and the NMAG 661 using the GRE Key option as described in [GREKEY], e.g., In the case 662 of the reactive mode as shown in Figure 3, the DL GRE key is 663 communicated in the HI message while the UL GRE key is sent in the 664 HAck message. For the downlink packets, the PMAG redirects mobile 665 node's packets from the local mobility anchor towards the NMAG and if 666 the mobile node is ready to receive those packets or the N-AN can 667 handle them regardless of the state of the mobile node, the NMAG 668 SHOULD immediately send them towards the N-AN; otherwise it SHOULD 669 buffer them until the mobile node is ready. For the uplink packets, 670 the NMAG SHOULD reverse-tunnel them from the mobile node towards the 671 PMAG and the PMAG sends them to the local mobility anchor. 673 When the PMAG or NMAG receives the HI message with the U flag set, it 674 prepares to buffer the mobile node's packets and returns the HAck 675 message with the same sequence number. It MUST be followed by 676 another HI message with the F flag set at an appropriate time to 677 forward the buffered packets. 679 If the MAG that received the HI message encounters an erroneous 680 situation (e.g., insufficient buffer space), it SHOULD immediately 681 send the HAck message with the cause of the error and cancel all 682 tunneling operation. 684 4.3. IPv4 Support Considerations 686 The motivation and usage scenarios of IPv4 protocol support by PMIPv6 687 are described in [IPv4PMIPv6]. The scope of IPv4 support covers the 688 following two features: 690 o IPv4 Home Address Mobility Support, and 692 o IPv4 Transport Support. 694 As for IPv4 Home Address Mobility Support, the mobile node acquires 695 IPv4 Home Address (IPv4-MN-HoA) and in the case of handover, the PMAG 696 needs to transfer IPv4-MN-HoA to the NMAG, which is the inner 697 destination address of the packets forwarded on the downlink. For 698 this purpose, IPv4 Address Option described in Section 6.2.7 is used. 699 In order to provide IPv4 Transport Support, the NMAG needs to know 700 the IPv4 address of the local mobility anchor (IPv4-LMAA) to send 701 PMIPv6 signaling messages to the local mobility anchor in the IPv4 702 transport network. For this purpose, a new option called LMA Address 703 (LMAA) Option is defined in Section 6.2.2 so as to convey IPv4-LMAA 704 from the PMAG to NMAG. 706 5. PMIPv6-related Fast Handover Issues 708 5.1. Manageability Considerations 710 This specification does not require any additional IP-level 711 functionality on the local mobility anchor and the mobile node 712 running in the PMIPv6 domain. A typical network interface that the 713 mobile node could be assumed to have is one with the cellular 714 network, where the network controls the movement of the mobile node. 715 Different types of interfaces could be involved such as different 716 generations (3G and 3.9G) or different radio access systems. This 717 specification supports a mobile node with the single radio mode, 718 where only one interface is active at any given time. The assigned 719 IP address is preserved whether the physical interface changes or not 720 and the mobile node can identify which interface should be used if 721 there are multiple ones. 723 5.2. Expedited Packet Transmission 725 The protocol specified in this document enables the NMAG to obtain 726 parameters which would otherwise be available only by communicating 727 with the local mobility anchor. For instance, the HNP(s) and/or 728 IPv4-MN-HoA of a mobile node are made available to the NMAG through 729 context transfer. This allows the NMAG to perform some procedures 730 that may be beneficial. The NMAG, for example, SHOULD send a Router 731 Advertisement (RA) with prefix information to the mobile node as soon 732 as its link attachment is detected (e.g., via receipt of a Router 733 Solicitation message). Such an RA is recommended, for example, in 734 scenarios where the mobile node uses a new radio interface while 735 attaching to the NMAG; since the mobile node does not have 736 information regarding the new interface, it will not be able to 737 immediately send packets without first receiving an RA with HNP(s). 738 Especially, in the reactive fast handover, the NMAG gets to know the 739 HNP(s) assigned to the mobile node on the previous link at step (d) 740 in Figure 3. In order to reduce the communication disruption time, 741 the NMAG SHOULD expect the mobile node to keep using the same HNP and 742 to send uplink packets before that step upon the mobile node's 743 request. However, if the HAck from the PMAG returns a different HNP 744 or the subsequent PMIPv6 binding registration for the HNP fails for 745 some reason, then the NMAG MUST withdraw the advertised HNP by 746 sending another RA with zero prefix lifetime for the HNP in question. 747 This operation is the same as described in Section 6.12 of [RFC5213]. 749 The protocol specified in this document is applicable regardless of 750 whether link-layer addresses are used between a mobile node and its 751 MAG. A mobile node should be able to continue sending packets on the 752 uplink even when it changes link. When link-layer addresses are 753 used, the mobile node performs Neighbor Unreachability Detection 754 (NUD) [RFC4861], after attaching to a new link, probing the 755 reachability of its default router. The new router should respond to 756 the NUD probe, providing its link-layer address in the solicited 757 Neighbor Advertisement, which is common in the PMIPv6 domain. 758 Implementations should allow the mobile node to continue to send 759 uplink packets while it is performing NUD. 761 6. Message Formats 763 This document defines new Mobility Header messages for the extended 764 HI and Hack and new mobility options for conveying context 765 information. 767 6.1. Mobility Header 769 6.1.1. Handover Initiate (HI) 771 This section defines extensions to the HI message in [RFC5568]. The 772 format of the Message Data field in the Mobility Header is as 773 follows: 775 0 1 2 3 776 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 1 777 +-------------------------------+ 778 | Sequence # | 779 +-+-+-+-+-------+---------------+-------------------------------+ 780 |S|U|P|F|Resv'd | Code | | 781 +-+-+-+-+-------+---------------+ | 782 | | 783 . . 784 . Mobility options . 785 . . 786 | | 787 +---------------------------------------------------------------+ 788 (Note:P=1) 790 IP Fields: 792 Source Address 794 The IP address of PMAG or NMAG 796 Destination Address 798 The IP address of the peer MAG 800 Message Data: 802 Sequence # Same as [RFC5568]. 804 S flag Defined in [RFC5568] and MUST be set to zero in this 805 specification. 807 U flag Buffer flag. Same as [RFC5568]. 809 P flag Proxy flag. Used to distinguish the message from that 810 defined in [RFC5568] and MUST be set in all new message 811 formats defined in this document when using this protocol 812 extension. 814 F flag Forwarding flag. Used to request to forward the packets 815 for the mobile node. 817 Reserved Same as [RFC5568]. 819 Code [RFC5568] defines this field and its values 0 and 1. In 820 this specification, with the P flag set, this field can 821 be set to zero by default or the following values: 823 2: Indicate the completion of forwarding 825 3: All available context transferred 827 Code value 3 is set when the transfer of all necessary 828 context information is completed with this message. This 829 Code value is used in both cases where the context 830 information is fragmented into several pieces and the 831 last fragment is contained in this message and where the 832 whole information is transferred in one piece. 834 Mobility options: 836 This field contains one or more mobility options, whose encoding and 837 formats are defined in [RFC3775]. 839 Required option 840 In order to uniquely identify the target mobile node, the 841 mobile node Identifier MUST be contained in the Mobile Node 842 Identifier Option. 844 The transferred context MUST be for one mobile node per message. In 845 addition, the NMAG can request necessary mobility options by the 846 Context Request Option defined in this document. 848 Context Request Option 850 This option MAY be present to request context information 851 typically by the NMAG to the PMAG in the NMAG-initiated fast 852 handover. 854 6.1.2. Handover Acknowledge (HAck) 856 This section defines extensions to the HAck message in[RFC5568]. The 857 format of the Message Data field in the Mobility Header is as 858 follows: 860 0 1 2 3 861 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 1 862 +-------------------------------+ 863 | Sequence # | 864 +-+-+-+---------+---------------+-------------------------------+ 865 |U|P|F|Reserved | Code | | 866 +-+-+-+---------+---------------+ | 867 | | 868 . . 869 . Mobility options . 870 . . 871 | | 872 +---------------------------------------------------------------+ 873 (Note:P=1) 875 IP Fields: 877 Source Address 879 Copied from the destination address of the 880 Handover Initiate message to which this message 881 is a response. 883 Destination Address 885 Copied from the source address of the Handover 886 Initiate message to which this message is a 887 response. 889 Message Data: 891 The usages of Sequence # and Reserved fields are exactly the same as 892 those in [RFC5568]. 894 U flag Same as defined in Section 6.1.1. 896 P flag Used to distinguish the message from that defined in 897 [RFC5568] and MUST be set in all new message formats 898 defined in this document when using this protocol 899 extension. 901 F flag Same as defined in Section 6.1.1. 903 Code 904 Code values 0 through 4 and 128 through 130 are defined 905 in [RFC5568]. When the P flag is set, the meaning of 906 Code value 0 is as defined in this specification, 128 907 through 130 are reused, and 5, 6, 131 and 132 are newly 908 defined. 910 0: Handover Accepted or Successful 912 5: Context Transfer Accepted or Successful 914 6: All available Context Transferred 916 128: Handover Not Accepted, reason unspecified 918 129: Administratively prohibited 920 130: Insufficient resources 922 131: Requested Context Not Available 924 132: Forwarding Not Available 926 Mobility options: 928 This field contains one or more mobility options, whose encoding and 929 formats are defined in [RFC3775]. The mobility option that uniquely 930 identifies the target mobile node MUST be copied from the 931 corresponding HI message and the transferred context MUST be for one 932 mobile node per message. 934 Required option(s) All the context information requested by the 935 Context Request Option in the HI message SHOULD be present 936 in the HAck message. The other cases are described below. 938 In the case of the PMAG-initiated fast handover, when the PMAG sends 939 the HI message to the NMAG with the context information and the NMAG 940 successfully receives it, the NMAG returns the HAck message with Code 941 value 5. In the case of the NMAG-initiated fast handover, when the 942 NMAG sends the HI message to the PMAG with or without Context Request 943 Option, the PMAG returns the HAck message with the requested or 944 default context information (if any). If all available context 945 information is transferred, the PMAG sets the Code value in the HAck 946 message to 6. If more context information is available, the PMAG 947 sets the Code value in the HAck to 5 and the NMAG MAY send new HI 948 message(s) to retrieve the rest of the available context information. 950 If none of the requested context information is available, the PMAG 951 returns the HAck message with Code value 131 without any context 952 information. 954 6.2. Mobility Options 956 6.2.1. Context Request Option 958 This option is sent in the HI message to request context information 959 on the mobile node. If a default set of context information is 960 defined and always sufficient, this option is not used. This option 961 is more useful to retrieve additional or dynamically selected context 962 information. 964 Context Request Option is typically used for the reactive (NMAG- 965 initiated) fast handover mode to retrieve the context information 966 from the PMAG. When this option is included in the HI message, all 967 the requested context information SHOULD be included in the HAck 968 message in the corresponding mobility option(s) (e.g., HNP, LMAA or 969 MN LL-ID mobility options). 971 The default context information to request is the Home Network Prefix 972 Option. If the Mobile Node link-layer is available and used, the 973 Mobile Node Link-layer Identifier Option MUST also be requested. 975 0 1 2 3 976 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 1 977 +---------------+---------------+---------------+---------------+ 978 | Option-Type | Option-Length | Reserved | 979 +---------------+---------------+-------------------------------+ 980 | Req-type-1 | Req-length-1 | Req-type-2 | Req-length-2 | 981 +---------------------------------------------------------------+ 982 | Req-type-3 | Req-length-3 | Req-option-3 | 983 +---------------------------------------------------------------+ 984 | ... | 986 Option-Type TBD1 988 Option-Length The length in octets of this option, not including the 989 Option Type and Option Length fields. 991 Reserved This field is unused. It MUST be initialized to zero 992 by the sender and MUST be ignored by the receiver. 994 Req-type-n The type value for the n'th requested option. 996 Req-length-n The length of the n'th requested option excluding the 997 Req-type-n and Req-length-n fields. 999 Req-option-n The optional data to uniquely identify the requested 1000 context for the n'th requested option. 1002 In the case where there are only Req-type-n and Req-length-n fields, 1003 the value of the Req-length-n is set to zero. If additional 1004 information besides the Req-type-n is necessary to uniquely specify 1005 the requested context, such information follows after the 1006 Req-length-n. For example, when the requested contexts start with 1007 the HNP Option (type=22), the MN Link-layer ID Option (type=25) and 1008 the Vendor-Specific Option (type=19), the required option format 1009 looks as follows: 1011 | ... | 1012 +---------------+---------------+---------------+---------------+ 1013 |Option-Type=CRO| Option-Length | Reserved | 1014 +---------------+---------------+---------------+---------------+ 1015 | Req-type-N=22 | Req-length-N=0| Req-type-N=25 | Req-length-N=0| 1016 +---------------+---------------+-------------------------------+ 1017 | Req-type-N=19 | Req-length-N=5| Vendor-ID | 1018 +-------------------------------+---------------+---------------+ 1019 | Vendor-ID | Sub-Type | | 1020 +-----------------------------------------------+ | 1021 | ... | 1023 The first two options can uniquely identify the requested contexts 1024 (i.e., the HNP and MN Link-layer ID) by the Req-type, so the Req- 1025 length is set to zero; however, the subsequent Vendor-Specific Option 1026 further needs the Vendor-ID and Sub-type to identify the requested 1027 context, so these parameters follow and the Req-length is set to 5. 1028 Note that the exact values in the Vendor-ID and Sub-Type follow 1029 [RFC5094]. 1031 6.2.2. Local Mobility Anchor Address (LMAA) Option 1033 This option is used to transfer the Local Mobility Anchor IPv6 1034 Address (LMAA) or its IPv4 Address (IPv4-LMAA), with which the mobile 1035 node is currently registered. The detailed definition of the LMAA is 1036 described in [RFC5213]. 1038 0 1 2 3 1039 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 1040 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1041 | Option-Type | Option-Length | Option-Code | Reserved | 1042 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1043 | Local Mobility Anchor Address ... | 1045 Option-Type TBD2 1047 Option-Length 18 or 6 1049 Option-Code 1051 0 Reserved 1053 1 IPv6 address of the local mobility anchor (LMAA) 1055 2 IPv4 address of the local mobility anchor (IPv4- 1056 LMAA) 1058 Reserved This field is unused. It MUST be initialized to zero 1059 by the sender and MUST be ignored by the receiver. 1061 Local Mobility Anchor Address 1062 If Option-Code is 1, the LMA IPv6 address (LMAA) is 1063 inserted. If Option-Code is 2, the LMA IPv4 address 1064 (IPv4-LMA) is inserted. 1066 6.2.3. Mobile Node Link-local Address Interface Identifier (MN LLA-IID) 1067 Option 1069 This option is used to transfer the interface identifier of the 1070 mobile node's IPv6 Link-local Address that is used in the P-AN. In 1071 deployments where the interface identifier is assigned by the 1072 network, or it is known to the network, this option is used to 1073 transfer this identifier from the PMAG to NMAG. 1075 0 1 2 3 1076 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 1077 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1078 | Option-Type | Option-Length | Reserved | 1079 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1080 | | 1081 + Interface Identifier + 1082 | | 1083 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1085 Option-Type TBD3 1087 Option-Length 10 1089 Reserved This field is unused. It MUST be initialized to zero 1090 by the sender and MUST be ignored by the receiver. 1092 Interface Identifier 1093 The Interface Identifier value used for the mobile 1094 node's IPv6 Link-local address in the P-AN. 1096 6.2.4. Home Network Prefix Option 1098 This option is used to transfer the home network prefix that is 1099 assigned to the mobile node in the P-AN. The Home Network Prefix 1100 Option defined in [RFC5213] is used for this. 1102 6.2.5. Link-local Address Option 1104 This option is used to transfer the link-local address of the PMAG 1105 (PMAG). The Link-local Address Option defined in [RFC5213] is used 1106 for this. 1108 6.2.6. GRE Key Option 1110 This option is used to transfer the GRE Key for the mobile node's 1111 data flow over the bi-directional tunnel between the PMAG and NMAG. 1112 The message format of this option follows the GRE Key Option defined 1113 in [GREKEY]. The GRE Key value uniquely identifies each flow and the 1114 sender of this option expects to receive packets of the flow from the 1115 peer AR with this value. 1117 6.2.7. IPv4 Address Option 1119 As described in Section 4.3, if the mobile node runs in IPv4-only 1120 mode or dual-stack mode, it requires IPv4 home address (IPv4-MN-HoA). 1121 This option is used to transfer the IPv4 home address if assigned on 1122 the previous link. The format of this option follows the IPv4 Home 1123 Address Request Option defined in [IPv4PMIPv6]. 1125 6.2.8. Vendor-Specific Mobility Option 1127 This option is used to transfer any other information defined in this 1128 document. The format and used values of this option follow the 1129 Vendor-Specific Mobility Option defined in [RFC5094]. 1131 7. Security Considerations 1133 Security issues for this document follow those for PMIPv6 [RFC5213] 1134 and FMIPv6 [RFC5568]. In PMIPv6, the MAG and local mobility anchor 1135 are assumed to share security associations. In FMIPv6, the access 1136 routers (i.e., the PMAG and NMAG in this document) are assumed to 1137 share security associations. 1139 The Handover Initiate (HI) and Handover Acknowledge (HAck) messages 1140 exchanged between the PMAG and NMAG MUST be protected using end-to- 1141 end security association(s) offering integrity and data origin 1142 authentication. The PMAG and the NMAG MUST implement IPsec [RFC4301] 1143 for protecting the HI and HAck messages. IPsec Encapsulating 1144 Security Payload (ESP) [RFC4303] in transport mode with mandatory 1145 integrity protection SHOULD be used for protecting the signaling 1146 messages. Confidentiality protection SHOULD be used if sensitive 1147 context related to the mobile node is transferred. 1149 IPsec ESP [RFC4303] in tunnel mode SHOULD be used to protect the 1150 mobile node's packets at the time of forwarding if the link between 1151 the PMAG and NMAG exposes the mobile node's packets to more threats 1152 than if they had followed their normal routed path. 1154 8. IANA Considerations 1156 This document defines new flags and status codes in the HI and HAck 1157 messages as well as three new mobility options. The Type values for 1158 these mobility options are assigned from the same numbering space as 1159 allocated for the other mobility options defined in [RFC3775]. Those 1160 for the flags and status codes are assigned from the corresponding 1161 numbering space defined in [RFC5568] and requested to be created as 1162 new tables in the IANA registry (marked with asterisks). New values 1163 for these registries can be allocated by Standards Action or IESG 1164 approval [RFC5226]. 1166 Mobility Options 1167 Value Description Reference 1168 ----- ------------------------------------- ------------- 1169 TBD1 Context Request Option Section 6.2.1 1170 TBD2 Local Mobility Anchor Address Option Section 6.2.2 1171 TBD3 Mobile Node Link-local Address 1172 Interface Identifier Option Section 6.2.3 1174 Handover Initiate Flags (*) 1175 Registration Procedures: Standards Action or IESG Approval 1176 Flag Value Description Reference 1177 ---- ----- ----------------------------------- ------------- 1178 S 0x80 Assigned Address Configuration flag [RFC5568] 1179 U 0x40 Buffer flag [RFC5568] 1180 P 0x20 Proxy flag Section 6.1.1 1181 F 0x10 Forwarding flag Section 6.1.1 1183 Handover Acknowledge Flags (*) 1184 Registration Procedures: Standards Action or IESG Approval 1185 Flag Value Description Reference 1186 ---- ----- ------------------------------- ------------- 1187 U 0x80 Buffer flag Section 6.1.2 1188 P 0x40 Proxy flag Section 6.1.2 1189 F 0x20 Forwarding flag Section 6.1.2 1191 Handover Initiate Status Codes (*) 1192 Registration Procedures: Standards Action or IESG Approval 1193 Code Description Reference 1194 ---- -------------------------------------- ------------- 1195 0 FBU with the PCoA as source IP address [RFC5568] 1196 1 FBU whose source IP address is not PCoA [RFC5568] 1197 2 Indicate the completion of forwarding Section 6.1.1 1198 3 All available context transferred Section 6.1.1 1200 4-255 Unassigned 1202 Handover Acknowledge Status Codes (*) 1203 Registration Procedures: Standards Action or IESG Approval 1204 Code Description Reference 1205 ---- --------------------------------------- ------------- 1206 0 Handover Accepted or Successful Section 6.1.2 1207 (with NCoA valid) [RFC5568] 1208 1 Handover Accepted, NCoA not valid [RFC5568] 1209 2 Handover Accepted, NCoA assigned [RFC5568] 1210 3 Handover Accepted, use PCoA [RFC5568] 1211 4 Message sent unsolicited [RFC5568] 1212 5 Context Transfer Accepted or Successful Section 6.1.2 1213 6 All available Context Transferred Section 6.1.2 1214 7-127 Unassigned 1215 128 Handover Not Accepted, reason unspecified [RFC5568] 1216 129 Administratively prohibited [RFC5568] 1217 130 Insufficient resources [RFC5568] 1218 131 Requested Context Not Available Section 6.1.2 1219 132 Forwarding Not Available Section 6.1.2 1220 133-255 Unassigned 1222 9. Acknowledgments 1224 The authors would like to specially thank Vijay Devarapalli and Sri 1225 Gundavelli for their thorough reviews of this document. 1227 The authors would also like to thank Charlie Perkins, Desire Oulai, 1228 Ahmad Muhanna, Giaretta Gerardo, Domagoj Premec, Marco Liebsch, Fan 1229 Zhao, Julien Laganier and Pierrick Seite for their passionate 1230 discussions in the working group mailing list. 1232 10. References 1234 10.1. Normative References 1236 [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., 1237 and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. 1239 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1240 Requirement Levels", BCP 14, RFC 2119, March 1997. 1242 [RFC5568] Koodli, R., "Mobile IPv6 Fast Handovers", RFC 5568, 1243 July 2009. 1245 [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support 1246 in IPv6", RFC 3775, June 2004. 1248 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 1249 Internet Protocol", RFC 4301, December 2005. 1251 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 1252 RFC 4303, December 2005. 1254 [RFC5094] Devarapalli, V., Patel, A., and K. Leung, "Mobile IPv6 1255 Vendor Specific Option", RFC 5094, December 2007. 1257 [IPv4PMIPv6] 1258 Wakikawa, R., Ed. and S. Gundavelli, "IPv4 Support for 1259 Proxy Mobile IPv6", 1260 draft-ietf-netlmm-pmip6-ipv4-support-18.txt, 1261 February 2010. 1263 [GREKEY] Muhanna, A., Ed., "GRE Key Option for Proxy Mobile IPv6", 1264 draft-ietf-netlmm-grekey-option-09.txt, May 2009. 1266 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1267 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 1268 May 2008. 1270 10.2. Informative References 1272 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 1273 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 1274 September 2007. 1276 [RFC4988] Koodli, R. and C. Perkins, "Mobile IPv4 Fast Handovers", 1277 RFC 4988, October 2007. 1279 Appendix A. Applicable Use Cases 1281 A.1. PMIPv6 Handoff Indication 1283 PMIPv6 [RFC5213] defines the Handoff Indicator Option and describes 1284 the type of the handoff and the values to set to the option. This 1285 document proposes one approach to determining the handoff type by the 1286 NMAG when the handoff of the mobile node is executed. 1288 According to [RFC5213], the following handoff types are defined: 1290 0) Reserved 1292 1) Attachment over a new interface 1294 2) Handoff between two different interfaces of the mobile node 1296 3) Handoff between mobile access gateways for the same interface 1298 4) Handoff state unknown 1300 5) Handoff state not changed (Re-registration) 1302 Assuming that there is a valid MN Link-layer Identifier (MN LL-ID), 1303 the following solution can be considered. When the NMAG receives the 1304 MN LL-ID from the PMAG in the MN LL-ID option via the HI or HAck 1305 message, the NMAG compares it with the new MN LL-ID that is obtained 1306 from the mobile node in the N-AN. If these two MN LL-IDs are the 1307 same, the handoff type falls into 3) and the Handoff Indicator value 1308 is set to 3. If these two MN LL-IDs are different, the handoff is 1309 likely to be 2) since the HI/HAck message exchange implies that this 1310 is a handoff not a multi-homing, therefore the Handoff Indicator 1311 value can be set to 2. If there is no HI/HAck exchange performed 1312 prior to the network attachment of the mobile node in the N-AN, the 1313 NMAG may infer that this is a multi-homing case and set the Handoff 1314 Indicator value to 1. In the case of re-registration, the MAG, to 1315 which the mobile node is attached, can determine if the handoff state 1316 is not changed, so the MAG can set the HI value to 5 without any 1317 additional information. If none of them can be assumed or there is 1318 no valid MN LL-ID available, the NMAG may set the value to 4. 1320 A.2. Local Routing 1322 Section 6.10.3 in [RFC5213] describes that if EnableMAGLocalRouting 1323 flag is set, when two mobile nodes are attached to one MAG, the 1324 traffic between them may be locally routed. If one mobile node moves 1325 from this MAG (PMAG) to another MAG (NMAG) and if the PMAG does not 1326 detect the mobile node's detachment, it will continue to forward 1327 packets locally forever. This situation is more likely to happen in 1328 the reactive fast handover with WLAN access, which does not have the 1329 capability to detect the detachment of the mobile node in a timely 1330 manner. This specification can be applied to handle this case. When 1331 the mobile node attaches to the NMAG, the NMAG sends the HI message 1332 to the PMAG with the 'F' flag set, which makes the PMAG realize the 1333 detachment of the mobile node and establish the inter-MAG tunnel. 1334 The PMAG immediately stops the local routing and sends the packets 1335 for the mobile node to the NMAG via that tunnel, which are then 1336 delivered to the mobile node on the new link. 1338 Appendix B. Change Log 1340 Changes at -00 1342 * Added separate sections for MH and ICMP. 1344 * Clarified usage of HNP and IPv4-MN-HoA throughout the document. 1346 * Added IANA Considerations. 1348 * Added section on Other Considerations, including operation of 1349 uplink packets when using link-layer addresses, multiple 1350 interface usage and transmission of RA to withdraw HNP in the 1351 event of failure of PMIP6 registration. 1353 * Revised Security Considerations. 1355 Changes from -00 to -01 1357 * Removed ICMPv6-based message format. 1359 * Clarified HI/HAck exchange in the predictive mode (step (e) in 1360 Figure 2). 1362 * Clarified information retrieval about the PMAG in the reactive 1363 mode. 1365 * Removed the extension to the GRE Key Option. 1367 * Clarified the handoff type considerations in Appendix A. 1369 * Home Network Prefix Option, Link-local Address Option and 1370 Vendor-Specific Mobility Option are added. 1372 Changes from -01 to -02 1374 * Aligned HI/HAck message formats with 1375 draft-ietf-mipshop-rfc5268bis-00.txt. 1377 * Revised Section 8 removing the request for the type assignment 1378 of HI/HAck Mobility Headers. 1380 Changes from -02 to -03 1382 * Updated HI/HAck message formats according to 1383 draft-ietf-mipshop-rfc5268bis-01.txt. 1385 * Cleaned up Figure 2 and Figure 3. 1387 * Moved PMIP domain boundary crossing situation in Section 4.1 to 1388 Appendix A.3. 1390 * Removed the alternative protocol operation with an unsolicited 1391 HAck from Section 4.1. 1393 * Modified Code values in the HAck message in order to avoid 1394 collision with those in draft-ietf-mipshop-rfc5268bis-01.txt. 1396 * Clarified the usage scenarios of Context Request Option. 1398 * Modified the description of Code values in the HAck message. 1400 * Changed the container for the IPv4-LMAA from IPv4 Address 1401 option to the LMAA option. 1403 * Made Confidentiality protection "SHOULD" for context transfer. 1405 Changes from -03 to -04 1407 * Added more explanations about MIPv6, FMIPv6 and PMIPv6 in 1408 Abstract. 1410 * Moved Figure 1 to Section 4. 1412 * More clearly indicated the FMIPv6 messages that are not 1413 applicable in the PMIPv6 context. 1415 * Mandated the support of IP Sec on the PMAG and NMAG in order to 1416 protect signaling and user packets and the context information. 1418 * Added a new section for the inter-AR tunneling operation 1419 (Section 4.2). 1421 * Added descriptions about the encapsulation type in Sections 4.1 1422 and 4.3. 1424 * Added a description about buffering requirements on the MAG in 1425 Section 4.1. 1427 * Added a description about the timing of L2 and L3 connection 1428 establishments in Section 4.1. 1430 * Added a new section for PMIPv6-related fast handover issues 1431 (Section 5) and a description about preferable behaviors of the 1432 mobile node and MAG to reduce packet loss. 1434 * Added Acknowledgments section (Section 9). 1436 * Added a new section for local routing in Appendix (A.2). 1438 Changes from -04 to -05 1440 * Fixed Figure 2 (step (i)). 1442 * Defined the Mobile Network Interface Identifier (MN-IID) 1443 mobility option in Section 6.2.4 (swapped with old Section 1444 6.2.5), and added it to IANA considerations (Section 8). 1446 * Changed from SHOULD to MUST regarding the inclusion of the 1447 MN-ID, MN-HNP, MN-IID and the LMAA options in the HI message 1448 (step (c) in Section 4.1). 1450 * The optional behavior of the NMAG that allows it to send uplink 1451 packets directly to the local mobility anchor before the PBU/ 1452 PBA exchange was removed from section 4.2 (as out of scope). 1454 * In Section A.3, the description about the HA address assignment 1455 from the NAR to the mobile node was removed (as out of scope). 1457 Changes from -05 to -06 1459 * Added 'P' flag in the HI and Hack messages to distinguish them 1460 from those in FMIPv6. 1462 * Made editorial corrections in Section 2 (Introduction), Section 1463 3 (Terminology), Section 4 (Protocol Overview) and Section 4.2 1464 (Inter-AR Tunneling Operation). 1466 * Added a description on how forwarded packets should be handled 1467 in the access network at step (f) in Section 4.1. 1469 * Added all types of encapsulation methods that should be 1470 supported in Section 4.1. 1472 * Revised the Code values for the HI message in Section 6.1.1. 1474 * Revised the Code values for the HAck message in Section 6.1.2 1475 and added a description of its usage at step (d) of the 1476 reactive handover mode in Section 4.1. 1478 * Removed the definition of the IP Address Option in Section 1479 6.2.3 and moved to Section 6.2.7, which currently refers to the 1480 IPv4 Home Address Option defined by RFC5555. Revised the IANA 1481 Consideration section accordingly. 1483 * Removed the Option-Code from the Mobile Node Identifier (MN 1484 IID) Option. 1486 * Removed Appendix A.3 (Handling of PMIPv6/MIPv6 switching). 1488 Changes from -06 to -07 1490 * Added explanations about defining and setting the 'P' flag for 1491 the HI and Hack messages in Sections 4 and 4.1. 1493 * Corrected the references for the encapsulation types in Section 1494 4.1. 1496 * Modified the Code values for the HI message in Section 6.1.1 to 1497 avoid overlapping with those in 1498 draft-ietf-mipshop-rfc5268bis-01.txt. 1500 * Modified the reference for the IPv4 Address Option from RFC5555 1501 to [IPv4PMIPv6] in Section 6.2.7. 1503 Changes from -07 to -08 1505 * Corrected the reference for the TLV-header UDP encapsulation in 1506 Section 4.1. 1508 * Updated the version number of the reference document 1509 [IPv4PMIPv6] and the option name defined by that document in 1510 Section 6.2.7. 1512 Changes from -08 to -09 1514 * Added a paragraph at the beginning of Section 4 describing the 1515 assumption related to the lower layer signaling. 1517 * Added a new section on the manageability considerations in 1518 Section 5 describing the configurations on the network and the 1519 mobile node assumed in this document. 1521 * Modified the assumed configuration of the MAG regarding its 1522 link-layer address in Section 5 (Section 5.2 in version -09). 1524 * Specified the requested option to identify the target MN for 1525 the inter-AR tunneling in Section 6.1.1. 1527 * Specified the default context information in the Context 1528 Request Option in Section 6.2.1. 1530 Changes from -09 to -10 1532 * Revised the document based on the comments from TSV-DIR, SEC- 1533 DIR, OPS-DIR and GEN-ART. 1535 + Split the abstract section in half for readability. 1537 + Added the definition of Localized Mobility Anchor (local 1538 mobility anchor) in Section 3. 1540 + Added the purpose of this document at the beginning of 1541 Section 4 to make the paragraph more complete. 1543 + Revised the third paragraph of the Security Consideration 1544 section for more precise expression. 1546 + Moved the description about the requirement to set the 'P' 1547 flag in HI/HAck to Sections 6.1.1 and 6.1.2. Also, noted 1548 the 'P' flag setting below the message formats. 1550 + Described the both 'P' and 'F' flags as newly defined ones 1551 in Section 4. 1553 + Clarified the usage of the Context Request Option if a 1554 default set of context information is defined in Section 1555 6.2.1 (changed from "not mandatory" to "not used"). 1557 + Modified the identifier for the interface on the MN to the 1558 MN's link-layer ID (MN LL-ID). 1560 + Corrected the local routing operation of the PMAG in 1561 Appendix A.2. 1563 * Revised the descriptions about the encapsulation mechanism for 1564 the inter-MAG tunnel in Section 4.2 and other related parts for 1565 clarification. 1567 * Also listed the new flags and status codes for the HI/HAck 1568 messages in the IANA Considerations section. 1570 * Elaborated on the example use of the Context Request Option in 1571 Section 6.2.1. 1573 Changes from -10 to -11 1575 * Changed the term "MN Interface Identifier (MN-IID) option" to 1576 "MN Link-local Address Interface Identifier (MN LLA-IID) 1577 option" in Section 6.2.3. Its usage is valid only when the 1578 network assigns the interface identifier. 1580 * Revised the description of the neighbor cache entry in Section 1581 4.1 to include the MN LLA-IID. 1583 Changes from -11 to -12 1585 * Changed the term "HO-Initiate" to "Handover indication". 1587 * Added the handover trigger from the PMAG to the mobile node 1588 ("Handover command") to clarify the timing of handover in 1589 Figure 2. 1591 * Revised IANA Considerations to include all values that are 1592 defined in RFC5568, but not in the IANA Registry yet. 1594 Changes from -12 to -13 1596 * Editorial corrections. 1598 Changes from -13 to -14 1600 * Corrections related to [RFC2119]. 1602 Authors' Addresses 1604 Hidetoshi Yokota 1605 KDDI Lab 1606 2-1-15 Ohara, Fujimino 1607 Saitama, 356-8502 1608 Japan 1610 Email: yokota@kddilabs.jp 1612 Kuntal Chowdhury 1613 Cisco Systems 1614 30 International Place 1615 Tewksbury, MA 01876 1616 USA 1618 Email: kchowdhury@cisco.com 1620 Rajeev Koodli 1621 Cisco Systems 1622 30 International Place 1623 Tewksbury, MA 01876 1624 USA 1626 Email: rkoodli@cisco.com 1628 Basavaraj Patil 1629 Nokia 1630 6000 Connection Drive 1631 Irving, TX 75039 1632 USA 1634 Email: basavaraj.patil@nokia.com 1636 Frank Xia 1637 Huawei USA 1638 1700 Alma Dr. Suite 500 1639 Plano, TX 75075 1640 USA 1642 Email: xiayangsong@huawei.com