idnits 2.17.1 draft-ietf-ipv6-optimistic-dad-05.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- ** It looks like you're using RFC 3978 boilerplate. You should update this to the boilerplate described in the IETF Trust License Policy document (see https://trustee.ietf.org/license-info), which is required now. -- Found old boilerplate from RFC 3667, Section 5.1 on line 14. -- Found old boilerplate from RFC 3978, Section 5.5 on line 627. -- Found old boilerplate from RFC 3979, Section 5, paragraph 1 on line 604. -- Found old boilerplate from RFC 3979, Section 5, paragraph 2 on line 611. -- Found old boilerplate from RFC 3979, Section 5, paragraph 3 on line 617. ** Found boilerplate matching RFC 3978, Section 5.4, paragraph 1 (on line 593), which is fine, but *also* found old RFC 2026, Section 10.4C, paragraph 1 text on line 34. ** The document seems to lack an RFC 3978 Section 5.1 IPR Disclosure Acknowledgement -- however, there's a paragraph with a matching beginning. Boilerplate error? ** This document has an original RFC 3978 Section 5.4 Copyright Line, instead of the newer IETF Trust Copyright according to RFC 4748. ** The document seems to lack an RFC 3978 Section 5.4 Reference to BCP 78 -- however, there's a paragraph with a matching beginning. Boilerplate error? ** This document has an original RFC 3978 Section 5.5 Disclaimer, instead of the newer disclaimer which includes the IETF Trust according to RFC 4748. ** The document uses RFC 3667 boilerplate or RFC 3978-like boilerplate instead of verbatim RFC 3978 boilerplate. After 6 May 2005, submission of drafts without verbatim RFC 3978 boilerplate is not accepted. The following non-3978 patterns matched text found in the document. That text should be removed or replaced: By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, or will be disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3668. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- == No 'Intended status' indicated for this document; assuming Proposed Standard Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the RFC 3978 Section 5.4 Copyright Line does not match the current year == The document seems to lack the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords. (The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (13 Feb 2005) is 7011 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Missing Reference: 'RFC3041' is mentioned on line 449, but not defined ** Obsolete undefined reference: RFC 3041 (Obsoleted by RFC 4941) == Unused Reference: 'KOODLI' is defined on line 542, but no explicit reference was found in the text ** Obsolete normative reference: RFC 2461 (Obsoleted by RFC 4861) ** Obsolete normative reference: RFC 2462 (Obsoleted by RFC 4862) -- Obsolete informational reference (is this intentional?): RFC 3315 (Obsoleted by RFC 8415) -- Obsolete informational reference (is this intentional?): RFC 3484 (Obsoleted by RFC 6724) == Outdated reference: A later version (-02) exists of draft-koodli-mobileip-fastv6-00 Summary: 10 errors (**), 0 flaws (~~), 6 warnings (==), 9 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IPv6 Working Group Nick 'Sharkey' Moore 3 INTERNET-DRAFT Monash University CTIE 4 13 Feb 2005 6 Optimistic Duplicate Address Detection for IPv6 7 9 Status of this Memo 11 By submitting this Internet-Draft, I certify that any applicable 12 patent or other IPR claims of which I am aware have been disclosed, 13 or will be disclosed, and any of which I become aware will be 14 disclosed, in accordance with RFC 3668. 16 Internet-Drafts are working documents of the Internet Engineering 17 Task Force (IETF), its areas, and its working groups. Note that 18 other groups may also distribute working documents as Internet- 19 Drafts. 21 Internet-Drafts are draft documents valid for a maximum of six months 22 and may be updated, replaced, or obsoleted by other documents at any 23 time. It is inappropriate to use Internet-Drafts as reference 24 material or to cite them other than as "work in progress." 26 The list of current Internet-Drafts can be accessed at 27 http://www.ietf.org/ietf/1id-abstracts.txt 29 The list of Internet-Draft Shadow Directories can be accessed at 30 http://www.ietf.org/shadow.html. 32 Copyright Notice 34 Copyright (C) The Internet Society (2004). All Rights Reserved. 36 Abstract 38 Optimistic Duplicate Address Detection is an interoperable 39 modification of the existing IPv6 Neighbor Discovery (RFC2461) and 40 Stateless Address Autoconfiguration (RFC2462) process. The intention 41 is to minimize address configuration delays in the successful case, 42 to reduce disruption as far as possible in the failure case and to 43 remain interoperable with unmodified hosts and routers. 45 Table of Contents 47 Status of this Memo ......................................... 1 48 Abstract .................................................... 1 49 Table of Contents ........................................... 2 50 1. Introduction ............................................. 3 51 1.1 Problem Statement ............................... 3 52 1.2 Definitions ..................................... 4 53 1.3 Abbreviations ................................... 5 54 2. Optimistic Behaviours .................................... 6 55 2.1 Optimistic Address Flag ......................... 6 56 2.2 Avoiding Disruption ............................. 6 57 2.3 Router Redirection .............................. 7 58 3. Modifications to RFC-compliant behaviour ................. 8 59 3.1 General ......................................... 8 60 3.2 Modifications to RFC 2461 Neighbor Discovery .... 8 61 3.3 Modifications to RFC 2462 SLAAC ................. 9 62 4. Protocol Operation ....................................... 10 63 4.1 Simple case ..................................... 10 64 4.2 Collision case .................................. 11 65 4.3 Interoperation cases ............................ 11 66 4.4 Pathological cases .............................. 12 67 5. Security Considerations .................................. 12 68 6. IANA Considerations ...................................... 12 69 Appendix A: Probability of Collision ........................ 13 70 A.1 The Birthday Paradox ............................ 13 71 A.2 Individual Moving Nodes ......................... 14 72 Normative References ........................................ 15 73 Informative References ...................................... 15 74 Author's Address ............................................ 16 75 Acknowledgments ............................................. 16 76 Full Copyright Statement .................................... 16 77 Intellectual Property Statement ............................. 17 78 Disclaimer of Validity ...................................... 17 80 1. Introduction 82 Optimistic Duplicate Address Detection (DAD) is a modification of the 83 existing IPv6 Neighbor Discovery (ND) [RFC2461] and Stateless Address 84 Autoconfiguration (SLAAC) [RFC2462] process. The intention is to 85 minimize address configuration delays in the successful case, and to 86 reduce disruption as far as possible in the failure case. 88 Optimistic DAD is a useful optimization because DAD is far more 89 likely to succeed than fail for a well-distributed random address 90 [SOTO]. Disruption is minimized by limiting nodes' participation in 91 Neighbor Discovery while their addresses are still Optimistic. 93 It is not the intention of this memo to improve the security, 94 reliability or robustness of DAD beyond that of existing standards, 95 merely to provide a method to make it faster. 97 1.1 Problem Statement 99 The existing IPv6 address configuration mechanisms provide adequate 100 collision detection mechanisms for the fixed hosts they were designed 101 for. However, a growing population of nodes need to maintain 102 continuous network access despite frequently changing their network 103 attachment. Optimizations to the DAD process are required to provide 104 these nodes with sufficiently fast address configuration. 106 An optimized DAD method needs to: 108 * provide interoperability with nodes using the current standards. 110 * remove the RetransTimer delay during address configuration. 112 * ensure the probability of address collision is not increased. 114 * improve the resolution mechanisms for address collisions. 116 * minimize disruption in the case of a collision. 118 It is not sufficient to merely reduce RetransTimer in order to reduce 119 the handover delay, as values of RetransTimer long enough to 120 guarantee detection of a collision are too long to avoid disruption 121 of time-critical services. 123 1.2 Definitions 125 Definitions of requirements keywords ('MUST NOT', 'SHOULD NOT', 126 'MAY', 'SHOULD', 'MUST') are in accordance with the IETF Best Current 127 Practice - RFC2119 [RFC2119] 129 Address Resolution - Process defined by [RFC2461] section 7.2. 131 Neighbor Unreachability Detection - Process defined by [RFC2461] 132 section 7.3. 134 Tentative Address - an address for which a node has not yet completed 135 DAD is regarded as Tentative: a single Neighbor Solicitation for 136 this address or a single Neighbor Advertisement defending this 137 address will cause the node to deconfigure the address and cease 138 using it. 140 Deprecated Address - an address which should not be used if an 141 alternative is available. 143 Optimistic Address - an address which is available for use despite 144 DAD not being fully complete. This memo places restrictions on 145 the use of Optimistic Addresses. 147 Preferred Address - an address which is neither Tentative, Deprecated 148 or Optimistic. 150 Optimistic Node - An Optimistic Node is one which is compliant with 151 the rules specified in this memo. 153 Standard Node - A Standard Node is one which is compliant with RFCs 154 2461 and 2462. 156 Link - A communication facility or medium over which nodes can 157 communicate at the link layer. 159 Neighbors - Nodes on the same link, which may therefore be competing 160 for the same IP addresses. 162 1.3 Abbreviations 164 DAD - Duplicate Address Detection. Technique used for SLAAC. See 165 [RFC2462] section 5.4. 167 ICMP Redirect - See [RFC2461] section 4.5. 169 NA - Neighbor Advertisement. See [RFC2461] sections 4.4 and 7. 171 NC - Neighbor Cache. See [RFC2461] section 5.1 and 7.3. 173 ND - Neighbor Discovery. The process described in [RFC2461] 175 NS - Neighbor Solicitation. See [RFC2461] sections 4.3 and 7. 177 ON - Optimistic Node. A node which is behaving according to the 178 rules of this memo. 180 RA - Router Advertisement. See [RFC2462] sections 4.2 and 6. 182 RS - Router Solicitation. See [RFC2461] sections 4.1 and 6. 184 SLAAC - StateLess Address AutoConfiguration. The process described 185 in [RFC2462] 187 SLLAO - Source Link Layer Address Option - an option to NS, RA and RS 188 messages, which gives the link layer address of the source of 189 the message. See [RFC2461] section 4.6.1. 191 TLLAO - Target Link Layer Address Option - an option to ICMP Redirect 192 messages and Neighbor Advertisements. See [RFC2461] sections 193 4.4, 4.5 and 4.6.1. 195 2. Optimistic DAD Behaviours 197 This non-normative section discusses Optimistic DAD behaviours. 199 2.1 Optimistic Addresses 201 [RFC2462] introduces the concept of Tentative (in 5.4) and Deprecated 202 (in 5.5.4) Addresses. Addresses which are neither are said to be 203 Preferred. Tentative addresses may not be used for communication, 204 and Deprecated addresses should not be used for new communications. 205 These address states may also be used by other standards documents, 206 for example Default Address Selection [RFC3484]. 208 This memo introduces a new address state, 'Optimistic', that is used 209 to mark an address which is available for use but which has not 210 completed DAD. Protocols that do not understand this state should 211 treat it equivalently to 'Deprecated', to indicate that the address 212 is available for use but should not be used if another suitable 213 address is available. If address states are recorded as individual 214 flags, this can easily be achieved by setting 'Deprecated' when 215 'Optimistic' is set. In any case, it is important to note that the 216 address lifetime rules of [RFC2462] still apply, and so an address 217 may be Deprecated as well as Optimistic. When DAD completes without 218 incident, the address becomes a Preferred or Deprecated address, as 219 per [RFC2462]. 221 2.2 Avoiding Disruption 223 In order to avoid interference, it is important that an Optimistic 224 node does not send any messages from an Optimistic Address which will 225 override its neighbors' Neighbor Cache (NC) entries for the address 226 it is trying to configure: doing so would disrupt the rightful owner 227 of the address in the case of a collision. 229 This is achieved by: 231 * clearing the 'Override' flag in Neighbor Advertisements for 232 Optimistic Addresses, which prevents neighbors from overriding 233 their existing NC entries. The 'Override' flag is already 234 defined [RFC2461] and used for Proxy Neighbor Advertisement. 236 * Never sending Neighbor Solicitations from an Optimistic Address. 237 NSs include a Source Link Layer Address Option (SLLAO), which 238 may cause Neighbor Cache disruption. NSs sent as part of DAD 239 are sent from the unspecified address, without a SLLAO. 241 * Never using an Optimistic Address as the source address of a Router 242 Solicitation with a SLLAO. Another address, or the unspecified 243 address, may be used, or the RS may be sent without a SLLAO. 245 An address collision with a router may cause neighboring 246 router's IsRouter flags for that address to be cleared. 247 However, routers do not appear to use the IsRouter flag for 248 anything, and the NA sent in response to the collision will 249 reassert the IsRouter flag. 251 2.3 Router Redirection 253 Neighbor Solicitations cannot be sent from Optimistic Addresses, and 254 so an ON cannot directly contact a neighbor which is not already in 255 its Neighbor Cache. Instead, the ON forwards packets via its default 256 router, relying on the router to forward the packets to their 257 destination. In accordance with RFC2461, the router should then 258 provide the ON with an ICMP Redirect, which may include a Target Link 259 Layer Address Option (TLLAO). If it does, this will update the ON's 260 NC, and direct communication can begin. If it does not, packets 261 continue to be forwarded via the router until the ON has a non- 262 Optimistic address from which to send an NS. 264 3. Modifications to RFC-mandated behaviour 266 All normative text in this memo is contained in this section. 268 3.1 General 270 * Optimistic DAD SHOULD NOT be used to configure addresses unless the 271 probability of collision is exceedingly small. 273 * Nodes implementing Optimistic DAD SHOULD additionally implement 274 Secure Neighbor Discovery [SEND]. 276 3.2 Modifications to RFC 2461 Neighbor Discovery 278 * (modifies 6.3.7) A node MUST NOT send a Router Solicitation with a 279 SLLAO from an Optimistic Address. Router Solicitations SHOULD 280 be sent from a non-Optimistic or the Unspecified Address, 281 however they MAY be sent from an Optimistic Address as long as 282 the SLLAO is not included. 284 * (modifies 7.2.2) A node MUST NOT use an Optimistic Address as the 285 source address of a Neighbor Solicitation. 287 * If the ON isn't told the SLLAO of the router in an RA, and it 288 cannot determine this information without breaching the rules 289 above, it MUST wait until DAD completes despite being unable to 290 send any packets to the router. 292 * (modifies 7.2.2) When a node has a unicast packet to send from an 293 Optimistic Address to a neighbor, but does not know the 294 neighbor's link-layer address, it MUST NOT perform Address 295 Resolution. It SHOULD forward the packet to a default router on 296 the link in the hope that the packet will be redirected. 297 Otherwise it SHOULD buffer the packet until DAD is complete. 299 3.3 Modifications to RFC 2462 Stateless Address Autoconfiguration 301 * (modifies 5.5) A host MAY choose to configure a new address as an 302 Optimistic Address. A host which does not know the SLLAO of its 303 router SHOULD NOT configure a new address as Optimistic. A 304 router SHOULD NOT configure an Optimistic Address. 306 * (modifies 5.4) As soon as the initial Neighbor Solicitation is 307 sent, the Optimistic Address is configured on the interface and 308 available for use immediately. The address MUST be flagged as 309 'Optimistic'. 311 * When the DAD completes for an Optimistic Address, the address is no 312 longer Optimistic and it becomes Preferred or Deprecated 313 according to the rules of [RFC2462]. 315 * (modifies 5.4.3) The node MUST NOT reply to a Neighbor Solicitation 316 for an Optimistic Address from the unspecified address. This NS 317 indicates that the address is a duplicate, and it MUST be 318 deconfigured as per the behaviour specified in RFC2462 for 319 Tentative addresses. 321 * (modifies 5.4.3) The node MUST reply to a Neighbor Solicitation for 322 an Optimistic Address from a unicast address, but the reply MUST 323 have the Override flag cleared (O=0). 325 4. Protocol Operation 327 This non-normative section provides clarification of the interactions 328 between Optimistic Nodes, and between Optimistic Nodes and Standard 329 Nodes. 331 The following cases all consider an Optimistic Node (ON) receiving a 332 Router Advertisement containing a new prefix and deciding to 333 autoconfigure a new address on that prefix. 335 The ON will immediately send out a Neighbor Solicitation to determine 336 if its new address is already in use. 338 4.1 Simple case 340 In the non-collision case, the address being configured by the new 341 node is unused and not present in the Neighbor Caches of any of its 342 neighbors. 344 There will be no response to its NS (sent from ::), and this NS will 345 not modify the state of neighbors' Neighbor Caches. 347 The ON already has the link-layer address of the router (from the 348 RA), and the router can determine the link-layer address of the ON 349 through standard Address Resolution. Communications can begin as 350 soon as the router and the ON have each others' link-layer addresses. 352 After the appropriate DAD delay has completed, the address is no 353 longer Optimistic, and becomes either Preferred or Deprecated as per 354 RFC2462. 356 4.2 Collision case 358 In the collision case, the address being configured by the new node 359 is already in use by another node, and present in the Neighbor Caches 360 (NCs) of neighbors which are communicating with this node. 362 The NS sent by the ON has the unspecified source address, ::, and no 363 SLLAO. This NS will not cause changes to the NC entries of 364 neighboring hosts. 366 The ON will hopefully already know all it needs to about the router 367 from the initial RA. However, if it needs to it can still send an RS 368 to ask for more information, but it may not include a SLLAO. This 369 forces an all-nodes multicast response from the router, but will not 370 disrupt other nodes' NCs. 372 In the course of establishing connections, the ON might have sent NAs 373 in response to received NSs. Since NAs sent from Optimistic 374 Addresses have O=0, they will not have overridden existing NC 375 entries, although they may have resulted in a colliding entry being 376 changed to state STALE. This change is recoverable through standard 377 NUD. 379 When an NA is received from the collidee defending the address, the 380 ON immediately stops using the address and deconfigures it. 382 Of course, in the meantime the ON may have sent packets which 383 identify it as the owner of its new Optimistic Address (for example, 384 Binding Updates in [MIPV6]). This may incur some penalty to the ON, 385 in the form of broken connections, and some penalty to the rightful 386 owner of the address, since it will receive (and potentially reply 387 to) the misdirected packets. It is for this reason that Optimistic 388 DAD should only be used where the probability of collision is very 389 low. 391 4.3 Interoperation cases 393 Once the Optimistic Address has completed DAD, it acts exactly like a 394 normal address, and so interoperation cases only arise while the 395 address is Optimistic. 397 If an ON attempts to configure an address currently Tentatively 398 assigned to a Standard Node, the Standard Node will see the Neighbor 399 Solicitation and deconfigure the address. 401 If a node attempts to configure an ON's Optimistic Address, the ON 402 will see the NS and deconfigure the address. 404 4.4 Pathological cases 406 Optimistic DAD suffers from similar problems to Standard DAD, for 407 example duplicates are not guaranteed to be detected if packets are 408 lost. 410 These problems exist, and are not gracefully recoverable, in Standard 411 DAD. Their probability in both Optimistic and Standard DAD can be 412 reduced by increasing the RFC2462 DupAddrDetectTransmits variable to 413 greater than 1. 415 This version of Optimistic DAD is dependant on the details of the 416 router behaviour, eg: that the router includes SLLAOs in RAs, and 417 that the router is willing to redirect traffic for the ON. Where the 418 router does not behave in this way, the behaviour of Optimistic DAD 419 inherently reverts to that of Standard DAD. 421 5. Security Considerations 423 There are existing security concerns with Neighbor Discovery and 424 Stateless Address Autoconfiguration, and this memo does not purport 425 to fix them. However, this memo does not significantly increase 426 security concerns either. 428 Secure Neighbor Discovery [SEND] provides protection against the 429 threats to Neighbor Discovery described in [RFC3756]. Optimistic 430 Duplicate Address Detection does not introduce any additional threats 431 to Neighbor Discovery if SEND is used. 433 6. IANA Considerations 435 This document has no actions for IANA. 437 Appendix A: Probability of Collision 439 In assessing the usefulness of Duplication Address Detection, the 440 probability of collision must be considered. Various mechanisms such 441 as SLAAC [RFC2462] and DHCPv6 [RFC3315] attempt to guarantee the 442 uniqueness of the address. The uniqueness of SLAAC depends on the 443 reliability of the manufacturing process (so that duplicate L2 444 addresses are not assigned) and human factors if L2 addresses can be 445 manually assigned. The uniqueness of DHCPv6 assigned addresses 446 relies on the correctness of implementation to ensure that no two 447 nodes can be given the same address. 449 Privacy Extensions to SLAAC [RFC3041] avoids these potential error 450 cases by picking an Interface Identifier (IID) at random from 2^62 451 possible 64-bit IIDs (allowing for the reserved U and G bits). No 452 attempt is made to guarantee uniqueness, but the probability can be 453 easily estimated, and as the following discussion shows, probability 454 of collision is exceedingly small. 456 A.1 The Birthday Paradox 458 When considering collision probability, the Birthday Paradox is 459 generally mentioned. When randomly selecting k values from n 460 possibilities, the probability of two values being the same is: 462 Pb(n,k) = 1-( n! / [ (n-k)! . n^k] ) 464 Calculating the probability of collision with this method is 465 difficult, however, as one of the terms is n!, and (2^62)! is an 466 unwieldy number. [SOTO], now expired, presented an upper bound for 467 the probability of collision which is rather easier to calculate for 468 large n: 470 Pb(n,k) <= 1-( [(n-k+1)/n] ^ [k-1] ) 472 which lets us calculate that even for large networks the probability 473 of any two nodes colliding is very small indeed: 475 Pb(2^62, 500) <= 5.4e-14 476 Pb(2^62, 5000) <= 5.4e-12 477 Pb(2^62, 50000) <= 5.4e-10 478 Pb(2^62, 500000) <= 5.4e-08 480 A.2 Individual Nodes 482 When considering the effect of collisions on an individual node, we 483 do not need to consider the Birthday Paradox. When a node moves into 484 a network with K existing nodes, the probability that it will not 485 collide with any of the distinct addresses in use is simply 1-K/N. 486 If it moves to such networks M times, the probability that it will 487 not cause a collision on any of those moves is (1-K/N)^M, thus the 488 probability of it causing at least one collision is: 490 Pc(n,k,m) = 1-[(1-k/n)^m] 492 Even considering a very large number of moves (m = 600000, slightly 493 more than one move per minute for one year) and rather crowded 494 networks (k=50000 nodes per network), the odds of collision for a 495 given node are vanishingly small: 497 Pc(2^62, 5000, 600000) = 6.66e-10 498 Pc(2^62, 50000, 600000) = 6.53e-09 500 Each such collision affects two nodes, so the probability of being 501 effected by a collision is twice this. Even if the node moves into 502 networks of 50000 nodes once per minute for 100 years, the 503 probability of it causing or suffering a collision at any point are a 504 little over 1 in a million. 506 Pc(2^62, 50000, 60000000) * 2 = 1.3e-06 508 Normative References 510 [RFC2119] S. Bradner. "Key words for use in RFCs to Indicate 511 Requirement Levels." Request for Comments (Best Current 512 Practice) 2119 (BCP 14), Internet Engineering Task Force, March 513 1997. 515 [RFC2461] T. Narten, E.Nordmark, W. Simpson. "Neighbor Discovery for 516 IP Version 6 (IPv6)." Request for Comments (Draft Standard) 517 2461, Internet Engineering Task Force, December 1998. 519 [RFC2462] S. Thomson, T. Narten. "IPv6 Stateless Address 520 Autoconfiguration." Request for Comments (Draft Standard) 2462, 521 Internet Engineering Task Force, December 1998. 523 [SEND] J. Arkko (Ed.), J. Kempf, B. Sommerfeld, B.Zill, P. Nikander. 524 SEcure Neighbor Discovery (SEND), revision 06. (draft-ietf- 525 send-ndopt-06). July 17, 2004. 527 Informative References 529 [RFC3315] R. Droms (Ed.), J. Bound, B. Volz, T. Lemon, C. Perkins, M. 530 Carney. "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)" 531 Request for Comments (Proposed Standard) 3315, Internet 532 Engineering Task Force, July 2003. 534 [RFC3484] R. Draves. "Default Address Selection for Internet Protocol 535 version 6 (IPv6)". Request for Comments (Proposed Standard) 536 3484, Internet Engineering Task Force, February 2003. 538 [RFC3756] P. Nikander, J. Kempf, E. Nordmark. "IPv6 Neighbor 539 Discovery (ND) Trust Models and Threats". Request for Comments 540 (Informational) 3756, Internet Engineering Task Force, May 2004 542 [KOODLI] R. Koodli, C. Perkins. Fast Handovers in Mobile IPv6, 543 revision 00 (draft-koodli-mobileip-fastv6-00). October 2000 ... 544 Expired April 2001. 546 [MIPV6] D. Johnson, C. Perkins, J. Arkko. Mobility Support in IPv6, 547 revision 24 (draft-ietf-mobileip-ipv6-24). June 2003 ... 548 Expired December 2003. 550 [SOTO] M. Bagnulo, I. Soto, A. Garcia-Martinez, A. Azcorra. Random 551 generation of interface identifiers, revision 00. (draft-soto- 552 mobileip-random-iids-00). January 2002 ... Expired July 2002. 554 Author's Address: 556 Nick 'Sharkey' Moore 557 or 558 Centre for Telecommunications and Information Engineering 559 Monash University 3800 560 Victoria, Australia 562 Comments should be sent to either of the above email addresses. 564 Acknowledgments 566 There is some precedent for this work in previous Internet Drafts and 567 in discussions in the MobileIP WG mailing list and at IETF-54. 569 Thanks to Greg Daley, Brett Pentland, Richard Nelson and Ahmet 570 Sekercioglu at Monash Uni CTIE for their feedback and encouragement. 571 More information is available at: 572 574 Thanks to all the MobileIP and IPng/IPv6 WG members who have 575 contributed to the debate. Especially and alphabetically: Jari 576 Arkko, JinHyeock Choi, Youn-Hee Han, James Kempf, Thomas Narten, 577 Richard Nelson, Pekka Nikander, Erik Nordmark, Soohong 'Daniel' Park, 578 Ed Remmel, Pekka Savola, Hesham Soliman, Ignatious Souvatzis, Jinmei 579 Tatuya, Dave Thaler, Pascal Thubert, Vladislav Yasevich and Alper 580 Yegin. 582 This work has been supported by the Australian Telecommunications 583 Cooperative Research Centre (ATcrc): 584 586 Funding for the RFC Editor function is currently provided by the 587 Internet Society. 589 Full Copyright Statement 591 Copyright (C) The Internet Society (2004). This document is subject 592 to the rights, licenses and restrictions contained in BCP 78 and 593 except as set forth therein, the authors retain all their rights. 595 Intellectual Property Statement 597 The IETF takes no position regarding the validity or scope of any 598 Intellectual Property Rights or other rights that might be claimed to 599 pertain to the implementation or use of the technology described in 600 this document or the extent to which any license under such rights 601 might or might not be available; nor does it represent that it has 602 made any independent effort to identify any such rights. Information 603 on the procedures with respect to rights in RFC documents can be 604 found in BCP 78 and BCP 79. 606 Copies of IPR disclosures made to the IETF Secretariat and any 607 assurances of licenses to be made available, or the result of an 608 attempt made to obtain a general license or permission for the use of 609 such proprietary rights by implementers or users of this 610 specification can be obtained from the IETF on-line IPR repository at 611 http://www.ietf.org/ipr. 613 The IETF invites any interested party to bring to its attention any 614 copyrights, patents or patent applications, or other proprietary 615 rights that may cover technology that may be required to implement 616 this standard. Please address the information to the IETF at ietf- 617 ipr@ietf.org. 619 Disclaimer of Validity 621 This document and the information contained herein are provided on an 622 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 623 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET 624 ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, 625 INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE 626 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 627 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.