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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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-18) exists of draft-ietf-netlmm-pmip6-ipv4-support-08 ** Obsolete normative reference: RFC 4306 (Obsoleted by RFC 5996) ** Obsolete normative reference: RFC 3775 (Obsoleted by RFC 6275) Summary: 3 errors (**), 0 flaws (~~), 3 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 NETLMM Working Group V. Devarapalli (ed.) 3 Internet-Draft WiChorus 4 Intended status: Standards Track R. Koodli (ed.) 5 Expires: September 5, 2009 Starent Networks 6 H. Lim 7 N. Kant 8 Stoke 9 S. Krishnan 10 Ericsson 11 J. Laganier 12 DOCOMO Euro-Labs 13 March 4, 2009 15 Heartbeat Mechanism for Proxy Mobile IPv6 16 draft-ietf-netlmm-pmipv6-heartbeat-05.txt 18 Status of this Memo 20 This Internet-Draft is submitted to IETF in full conformance with the 21 provisions of BCP 78 and BCP 79. This document may not be modified, 22 and derivative works of it may not be created, except to format it 23 for publication as an RFC or to translate it into languages other 24 than English. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF), its areas, and its working groups. Note that 28 other groups may also distribute working documents as Internet- 29 Drafts. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 The list of current Internet-Drafts can be accessed at 37 http://www.ietf.org/ietf/1id-abstracts.txt. 39 The list of Internet-Draft Shadow Directories can be accessed at 40 http://www.ietf.org/shadow.html. 42 This Internet-Draft will expire on September 5, 2009. 44 Copyright Notice 46 Copyright (c) 2009 IETF Trust and the persons identified as the 47 document authors. All rights reserved. 49 This document is subject to BCP 78 and the IETF Trust's Legal 50 Provisions Relating to IETF Documents in effect on the date of 51 publication of this document (http://trustee.ietf.org/license-info). 52 Please review these documents carefully, as they describe your rights 53 and restrictions with respect to this document. 55 Abstract 57 Proxy Mobile IPv6 is a network-based mobility management protocol. 58 The mobility entities involved in the Proxy Mobile IPv6 protocol, the 59 Mobile Access Gateway (MAG) and the Local Mobility Anchor (LMA), 60 setup tunnels dynamically to manage mobility for a mobile node within 61 the Proxy Mobile IPv6 domain. This document describes a heartbeat 62 mechanism between the MAG and the LMA to detect failures quickly and 63 take appropriate action. 65 Table of Contents 67 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 68 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 69 3. Heartbeat Mechanism . . . . . . . . . . . . . . . . . . . . . 3 70 3.1. Failure Detection . . . . . . . . . . . . . . . . . . . . 4 71 3.2. Restart Detection . . . . . . . . . . . . . . . . . . . . 5 72 3.3. Heartbeat Message . . . . . . . . . . . . . . . . . . . . 5 73 3.4. Restart Counter Mobility Option . . . . . . . . . . . . . 7 74 4. Exchanging Heartbeat Messages over an IPv4 Transport 75 Network . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 76 5. Configuration Variables . . . . . . . . . . . . . . . . . . . 8 77 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 78 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 79 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 80 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 81 9.1. Normative References . . . . . . . . . . . . . . . . . . . 9 82 9.2. Informative References . . . . . . . . . . . . . . . . . . 10 83 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 85 1. Introduction 87 Proxy Mobile IPv6 [RFC5213] enables network-based mobility for IPv6 88 hosts that do not implement any mobility protocols. The protocol is 89 described in detail in [RFC5213]. In order to facilitate the 90 network-based mobility, the PMIPv6 protocol defines a Mobile Access 91 Gateway (MAG), which acts as a proxy for the Mobile IPv6 [RFC3775] 92 signaling, and the Local Mobility Anchor (LMA) which acts similar to 93 a Home Agent, anchoring a Mobile Node's sessions within a Proxy 94 Mobile IPv6 (PMIPv6) domain. The LMA and the MAG establish a 95 bidirectional tunnel for forwarding all data traffic belonging to the 96 Mobile Nodes. 98 In a distributed environment such as a PMIPv6 domain consisting of 99 LMA and MAGs, it is necessary for the nodes to 1) have a consistent 100 state about each other's reachability, and 2) quickly inform peers in 101 the event of recovery from node failures. So, when the LMA restarts 102 after a failure, the MAG should (quickly) learn about the restart so 103 that it could take appropriate actions (such as releasing any 104 resources). When there are no failures, a MAG should know about 105 LMA's reachability (and vice versa) so that the path can be assumed 106 to be functioning. 108 This document specifies a heartbeat mechanism between the MAG and the 109 LMA to detect the status of reachability between them. This document 110 also specifies a mechanism to indicate node restarts; the mechanism 111 could be used to quickly inform peers of such restarts. The 112 heartbeat message is a mobility header message (protocol type 135) 113 which is periodically exchanged at a configurable threshold of time 114 or sent unsolicited soon after a node restart. This document does 115 not specify the specific actions (such as releasing resources) that a 116 node takes as a response to processing the heartbeat messages. 118 2. Terminology 120 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 121 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 122 document are to be interpreted as described in [RFC2119]. 124 3. Heartbeat Mechanism 126 The MAG and the LMA exchange heartbeat messages every 127 HEARTBEAT_INTERVAL seconds to detect the current status of 128 reachability between them. The MAG initiates the heartbeat exchange 129 to test if the LMA is reachable by sending a Heartbeat Request 130 message to the LMA. Each Heartbeat Request contains a sequence 131 number that is incremented monotonically. The sequence number on the 132 last Heartbeat Request message is always recorded by the MAG, and is 133 used to match the corresponding Heartbeat Response. Similarly, the 134 LMA also initiates a heartbeat exchange with the MAG, by sending a 135 Heartbeat Request message, to check if the MAG is reachable. The 136 format of the Heartbeat message is described in Section 3.3. 138 A Heartbeat Request message can be sent only if the MAG has at least 139 one proxy binding cache entry at the LMA for a mobile node attached 140 to the MAG. If there are no proxy binding cache entries at the LMA 141 for any of the mobile nodes attached to the MAG, then the heartbeat 142 message SHOULD NOT be sent. Similarly, the LMA SHOULD NOT send a 143 Heartbeat Request message to a MAG if there is no active binding 144 cache entry created by the MAG. A PMIPv6 node SHOULD always respond 145 to a Heartbeat Request message with a Heartbeat Response message, 146 irrespective of whether there is an active binding cache entry. 148 The HEARTBEAT_INTERVAL SHOULD NOT be configured to a value less than 149 30 seconds. Sending heartbeat messages too often may become an 150 overhead on the path between the MAG and the LMA. The 151 HEARTBEAT_INTERVAL can be set to a much larger value on the LMA, if 152 required, to reduce the burden of sending periodic heartbeat 153 messages. 155 If the LMA or the MAG do not support the heartbeat messages, they 156 respond with a Binding Error message with status set to '2' 157 (unrecognized MH type value) as described in [RFC3775]. When the 158 Binding Error message with status set to '2' is received in response 159 to Heartbeat Request message, the initiating MAG or the LMA MUST NOT 160 use heartbeat messages with the other end again. 162 If a PMIPv6 node has detected that a peer PMIPv6 node has failed or 163 restarted without retaining the PMIPv6 session state, it should mark 164 the corresponding binding update list or binding cache entries as 165 invalid. The PMIPv6 node may also take other actions which are 166 outside the scope of this document. 168 3.1. Failure Detection 170 A PMIPv6 node, (MAG or LMA) matches every received Heartbeat Response 171 to the Heartbeat Request sent using the sequence number. Before 172 sending the next Heartbeat Request, it increments a local variable 173 MISSING_HEARTBEAT if it has not received a Heartbeat Response for the 174 previous request. When this local variable MISSING_HEARTBEAT exceeds 175 a configurable parameter MISSING_HEARTBEATS_ALLOWED, the PMIPv6 node 176 concludes that the peer PMIPv6 node is not reachable. If a Heartbeat 177 Response message is received, the MISSING_HEARTBEATS counter is 178 reset. 180 3.2. Restart Detection 182 The section describes a mechanism for detecting failure recovery 183 without session persistence. In case the LMA or the MAG crashes and 184 re-boots and loses all state with respect to the PMIPv6 sessions, it 185 would be beneficial for the peer PMIPv6 node to discover the failure 186 and the loss of session state and establish the sessions again. 188 Each PMIPv6 node (both the MAG and LMA) MUST maintain a monotonically 189 increasing Restart Counter that is incremented every time the node 190 re-boots and looses PMIPv6 session state. The counter MUST NOT be 191 incremented if the recovery happens without losing state for the 192 PMIPv6 sessions active at the time of failure. This counter MUST be 193 stored in non-volatile memory. A PMIPv6 node includes a Restart 194 Counter mobility option, described in Section 3.4 in an Heartbeat 195 Response message to indicate the current value of the Restart 196 Counter. Each PMIPv6 node MUST also store the Restart Counter for 197 all the peer PMIPv6 nodes that it has sessions with currently. 198 Storing the Restart Counter values for peer PMIPv6 nodes does not 199 require non-volatile memory. 201 The PMIPv6 node that receives the Heartbeat Response message compares 202 the Restart Counter value with the previously received value. If the 203 value is different, the receiving node assumes that the peer PMIPv6 204 node had crashed and recovered. If the Restart Counter value changes 205 or if there was no previously stored value, the new value is stored 206 by the receiving PMIPv6 node. 208 If a PMIPv6 node restarts and looses PMIPv6 session state, it SHOULD 209 send an unsolicited Heartbeat Response message with an incremented 210 Restart Counter to all the PMIPv6 nodes that had previously 211 established PMIPv6 sessions. Note that this is possible only when 212 the PMIPv6 node stores information about the peers in non-volatile 213 memory. The unsolicited Heartbeat Response message allows the peer 214 PMIPv6 nodes to quickly discover the restart. The sequence number 215 field in the unsolicited Heartbeat Response is ignored and no 216 response is necessary; the nodes will synchronize during the next 217 Request and Response exchange. 219 3.3. Heartbeat Message 221 The Heartbeat Message is based on the Mobility Header defined in 222 Section 6.1 of [RFC3775]. The 'MH type' field in the Mobility Header 223 indicates that it is a Heartbeat Message. This document does not 224 make any other changes to the Mobility Header message. Please refer 225 to [RFC3775] for a description of the fields in the Mobility Header 226 Message. 228 0 1 2 3 229 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 1 230 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 231 | Payload Proto | Header Len | MH Type | Reserved | 232 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 233 | Checksum | | 234 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 235 | | 236 . . 237 . Message Data . 238 . . 239 | | 240 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 242 Figure 1: Mobility Header Message Format 244 The Heartbeat Message follows the 'Checksum' field in the above 245 message. The following illustrates the message format for the 246 Heartbeat Mobility Header message. 248 0 1 2 3 249 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 1 250 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 251 | Reserved |U|R| 252 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 253 | Sequence Number | 254 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 255 | | 256 . . 257 . Mobility options . 258 . . 259 | | 260 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 262 Figure 2: Heartbeat Message Format 264 Reserved 266 Set to 0 and ignored by the receiver. 268 'U' 270 Set to 1 in Unsolicited Heartbeat Response. Otherwise set to 0. 272 'R' 274 A 1-bit flag that indicates whether the message is a request or a 275 response. When the 'R' flag is set to 0, it indicates that the 276 Heartbeat message is a request. When the 'R' flag is set to 1, it 277 indicates that the Heartbeat message is a response. 279 Sequence Number 281 A 32-bit sequence number used for matching the request to the 282 reply. 284 Mobility Options 286 Variable-length field of such length that the complete Mobility 287 Header is an integer multiple of 8 octets long. This field 288 contains zero or more TLV-encoded mobility options. The receiver 289 MUST ignore and skip any options which it does not understand. At 290 the time of writing this document, the Restart Counter Mobility 291 Option, described in Section 3.4, is the only valid option in this 292 message. 294 3.4. Restart Counter Mobility Option 296 The following shows the message format for a new mobility option for 297 carrying the Restart Counter Value in the Heartbeat message. The 298 Restart Counter Mobility Option is only valid in a Heartbeat Response 299 message. It has an alignment requirement of 4n+2. 301 0 1 2 3 302 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 1 303 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 304 | Type | Length | 305 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 306 | Restart Counter | 307 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 309 Figure 3: Restart Counter Mobility Option 311 Type 313 A 8-bit field that indicates that it is a Restart Counter mobility 314 option. 316 Length 318 A 8-bit field that indicates the length of the option in octets 319 excluding the 'Type' and 'Length' fields. It is set to '4'. 321 Restart Counter 323 A 32-bit field that indicates the current Restart Counter value. 325 4. Exchanging Heartbeat Messages over an IPv4 Transport Network 327 In some deployments, the network between the MAG and the LMA may not 328 be capable of transporting IPv6 packets. In this case, the Heartbeat 329 messages are tunneled over IPv4. If the Proxy Binding Update and 330 Proxy Binding Acknowledgment messages are sent using UDP 331 encapsulation to traverse NATs, then the Heartbeat messages are also 332 sent with UDP encapsulation. The UDP port used would be the same as 333 the port used for the Proxy Binding Update and Proxy Binding 334 Acknowledgement messages. For more details on tunneling Proxy Mobile 335 IPv6 signaling messages over IPv4, see 336 [I-D.ietf-netlmm-pmip6-ipv4-support]. 338 5. Configuration Variables 340 The LMA and the MAG must allow the following variables to be 341 configurable. 343 HEARTBEAT_INTERVAL 345 This variable is used to set the time interval in seconds between 346 two consecutive Heartbeat Request messages. The default value is 347 60 seconds. It SHOULD NOT be set to less than 30 seconds. 349 MISSING_HEARTBEATS_ALLOWED 351 This variable indicates the maximum number of consecutive 352 Heartbeat Request messages that a PMIPv6 node can miss before 353 concluding that the peer PMIPv6 node is not reachable. The 354 default value for this variable is 3. 356 6. Security Considerations 358 The heartbeat messages are just used for checking reachability 359 between the MAG and the LMA. They do not carry information that is 360 useful for eavesdroppers on the path. Therefore, confidentiality 361 protection is not required. Integrity protection using IPsec 362 [RFC4301] for the heartbeat messages MUST be supported on the MAG and 363 the LMA. RFC 4877 [RFC4877] describes how to protect Mobile IPv6 364 Binding Update and Acknowledgment signaling with IPsec. The 365 Heartbeat message defined in this specification is merely another 366 subtype of the same Mobility Header protocol that is already being 367 protected by IPsec. Therefore, protecting this additional message is 368 possible using the mechanisms and security policy models from these 369 RFCs. The security policy database entries should use the new MH 370 Type, the Heartbeat Message, for the MH Type selector. See RFC 4877 371 for more details. 373 If dynamic key negotiation between the MAG and the LMA is required, 374 IKEv2 [RFC4306] should be used. 376 7. IANA Considerations 378 The Heartbeat message defined in Section 3.3 must have the type value 379 allocated from the same space as the 'MH Type' name space in the 380 Mobility Header defined in RFC 3775 [RFC3775]. 382 The Restart Counter mobility option defined in Section 3.4 must have 383 the type value allocated from the same name space as the Mobility 384 Options defined in RFC 3775 [RFC3775]. 386 8. Acknowledgments 388 A heartbeat mechanism for a network-based mobility management 389 protocol was first described in [I-D.giaretta-netlmm-dt-protocol]. 390 The authors would like to thank the members of a NETLMM design team 391 that produced that document. The mechanism described in this 392 document also derives from the path management mechanism described in 393 [GTP]. 395 We would like to thank Alessio Casati for first suggesting a fault 396 handling mechanism for Proxy Mobile IPv6. 398 9. References 400 9.1. Normative References 402 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 403 Requirement Levels", BCP 14, RFC 2119, March 1997. 405 [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., 406 and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. 408 [I-D.ietf-netlmm-pmip6-ipv4-support] 409 Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy 410 Mobile IPv6", draft-ietf-netlmm-pmip6-ipv4-support-08 411 (work in progress), January 2009. 413 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 414 Internet Protocol", RFC 4301, December 2005. 416 [RFC4306] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", 417 RFC 4306, December 2005. 419 [RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with 420 IKEv2 and the Revised IPsec Architecture", RFC 4877, 421 April 2007. 423 [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support 424 in IPv6", RFC 3775, June 2004. 426 9.2. Informative References 428 [I-D.giaretta-netlmm-dt-protocol] 429 Giaretta, G., "The NetLMM Protocol", 430 draft-giaretta-netlmm-dt-protocol-02 (work in progress), 431 October 2006. 433 [GTP] 3rd Generation Partnership Project, "3GPP Technical 434 Specification 29.060 V7.6.0: "Technical Specification 435 Group Core Network and Terminals; General Packet Radio 436 Service (GPRS); GPRS Tunnelling Protocol (GTP) across the 437 Gn and Gp interface (Release 7)"", July 2007. 439 Authors' Addresses 441 Vijay Devarapalli 442 WiChorus 443 3950 North First Street 444 San Jose, CA 95134 445 USA 447 Email: vijay@wichorus.com 448 Rajeev Koodli 449 Starent Networks 450 USA 452 Email: rkoodli@starentnetworks.com 454 Heeseon Lim 455 Stoke 456 5403 Betsy Ross Drve 457 Santa Clara, CA 95054 458 USA 460 Email: hlim@stoke.com 462 Nishi Kant 463 Stoke 464 5403 Betsy Ross Drive 465 Santa Clara, CA 95054 466 USA 468 Email: nishi@stoke.com 470 Suresh Krishnan 471 Ericsson 472 8400 Decarie Blvd. 473 Town of Mount Royal, QC 474 Canada 476 Email: suresh.krishnan@ericsson.com 478 Julien Laganier 479 DOCOMO Euro-Labs 480 Landsbergerstrasse 312 481 Munich, D-80687 482 Germany 484 Email: julien.IETF@laposte.net