idnits 2.17.1 draft-ietf-mip6-bootstrapping-split-06.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 3978, Section 5.1 on line 18. -- Found old boilerplate from RFC 3978, Section 5.5, updated by RFC 4748 on line 1199. -- Found old boilerplate from RFC 3979, Section 5, paragraph 1 on line 1210. -- Found old boilerplate from RFC 3979, Section 5, paragraph 2 on line 1217. -- Found old boilerplate from RFC 3979, Section 5, paragraph 3 on line 1223. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust Copyright Line does not match the current year -- 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 (July 8, 2007) is 6137 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 3775 (ref. '1') (Obsoleted by RFC 6275) ** Obsolete normative reference: RFC 4306 (ref. '5') (Obsoleted by RFC 5996) -- Obsolete informational reference (is this intentional?): RFC 3041 (ref. '11') (Obsoleted by RFC 4941) == Outdated reference: A later version (-06) exists of draft-ietf-mip6-bootstrapping-integrated-dhc-04 == Outdated reference: A later version (-06) exists of draft-ietf-mip6-radius-02 == Outdated reference: A later version (-17) exists of draft-ietf-dime-mip6-split-02 -- Obsolete informational reference (is this intentional?): RFC 2845 (ref. '19') (Obsoleted by RFC 8945) == Outdated reference: A later version (-18) exists of draft-ietf-mip6-hiopt-05 -- Obsolete informational reference (is this intentional?): RFC 3280 (ref. '22') (Obsoleted by RFC 5280) Summary: 3 errors (**), 0 flaws (~~), 5 warnings (==), 10 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 MIP6 Working Group G. Giaretta, Ed. 3 Internet-Draft Qualcomm 4 Intended status: Standards Track J. Kempf 5 Expires: January 9, 2008 DoCoMo Labs USA 6 V. Devarapalli, Ed. 7 Azaire Networks 8 July 8, 2007 10 Mobile IPv6 bootstrapping in split scenario 11 draft-ietf-mip6-bootstrapping-split-06 13 Status of this Memo 15 By submitting this Internet-Draft, each author represents that any 16 applicable patent or other IPR claims of which he or she is aware 17 have been or will be disclosed, and any of which he or she becomes 18 aware will be disclosed, in accordance with Section 6 of BCP 79. 20 Internet-Drafts are working documents of the Internet Engineering 21 Task Force (IETF), its areas, and its working groups. Note that 22 other groups may also distribute working documents as Internet- 23 Drafts. 25 Internet-Drafts are draft documents valid for a maximum of six months 26 and may be updated, replaced, or obsoleted by other documents at any 27 time. It is inappropriate to use Internet-Drafts as reference 28 material or to cite them other than as "work in progress." 30 The list of current Internet-Drafts can be accessed at 31 http://www.ietf.org/ietf/1id-abstracts.txt. 33 The list of Internet-Draft Shadow Directories can be accessed at 34 http://www.ietf.org/shadow.html. 36 This Internet-Draft will expire on January 9, 2008. 38 Copyright Notice 40 Copyright (C) The IETF Trust (2007). 42 Abstract 44 A Mobile IPv6 node requires a Home Agent address, a home address, and 45 IPsec security associations with its Home Agent before it can start 46 utilizing Mobile IPv6 service. RFC 3775 requires that some or all of 47 these are statically configured. This document defines how a Mobile 48 IPv6 node can bootstrap this information from non-topological 49 information and security credentials pre-configured on the Mobile 50 Node. The solution defined in this document solves the split 51 scenario described in the Mobile IPv6 bootstrapping problem statement 52 in RFC 4640. The split scenario refers the case where the Mobile 53 Node's mobility service is authorized by a different service provider 54 than basic network access. The solution described in this document 55 is also generically applicable to any bootstrapping case, since other 56 scenarios are more specific realizations of the split scenario. 58 Table of Contents 60 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 61 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 62 3. Split scenario . . . . . . . . . . . . . . . . . . . . . . . . 4 63 4. Components of the solution . . . . . . . . . . . . . . . . . . 7 64 5. Protocol Operations . . . . . . . . . . . . . . . . . . . . . 9 65 5.1. Home Agent Address Discovery . . . . . . . . . . . . . . . 9 66 5.1.1. DNS lookup by Home Agent Name . . . . . . . . . . . . 9 67 5.1.2. DNS lookup by service name . . . . . . . . . . . . . . 10 68 5.2. IPsec Security Associations setup . . . . . . . . . . . . 11 69 5.3. Home Address assignment . . . . . . . . . . . . . . . . . 11 70 5.3.1. Home Address assignment by the Home Agent . . . . . . 11 71 5.3.2. Home Address auto-configuration by the Mobile Node . . 11 72 5.4. Authorization and Authentication with MSA . . . . . . . . 13 73 6. Home Address registration in the DNS . . . . . . . . . . . . . 14 74 7. Summary of Bootstrapping Protocol Flow . . . . . . . . . . . . 16 75 8. Option and Attribute Format . . . . . . . . . . . . . . . . . 17 76 8.1. DNS Update mobility option . . . . . . . . . . . . . . . . 17 77 8.2. MIP6_HOME_PREFIX attribute . . . . . . . . . . . . . . . . 18 78 9. Security Considerations . . . . . . . . . . . . . . . . . . . 19 79 9.1. HA Address Discovery . . . . . . . . . . . . . . . . . . . 19 80 9.2. Home Address Assignment through IKEv2 . . . . . . . . . . 21 81 9.3. SA Establishment Using EAP Through IKEv2 . . . . . . . . . 22 82 9.4. Back End Security Between the HA and AAA Server . . . . . 22 83 9.5. Dynamic DNS Update . . . . . . . . . . . . . . . . . . . . 22 84 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23 85 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 23 86 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 24 87 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 24 88 13.1. Normative References . . . . . . . . . . . . . . . . . . . 24 89 13.2. Informative References . . . . . . . . . . . . . . . . . . 25 90 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26 91 Intellectual Property and Copyright Statements . . . . . . . . . . 27 93 1. Introduction 95 Mobile IPv6 [1] requires the Mobile Node to know its Home Agent 96 Address, its own Home Address and the cryptographic materials (e.g. 97 shared keys or certificates) needed to set up IPsec security 98 associations with the Home Agent in order to protect Mobile IPv6 99 signaling. This is generally referred to as the Mobile IPv6 100 bootstrapping problem [6]. 102 Mobile IPv6 base protocol does not specify any method to 103 automatically acquire this information, which means that network 104 administrators are normally required to manually set configuration 105 data on Mobile Nodes and HAs. However, in real deployments, manual 106 configuration does not scale as the Mobile Nodes increase in number. 108 As discussed in [6], several bootstrapping scenarios can be 109 identified depending on the relationship between the network operator 110 that authenticates a mobile node for granting network access service 111 (Access Service Authorizer, ASA) and the service provider that 112 authorizes Mobile IPv6 service (Mobility Service Authorizer, MSA). 113 This document describes a solution to the bootstrapping problem that 114 is applicable in a scenario where the MSA and the ASA are different 115 entities (i.e. split scenario). 117 2. Terminology 119 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 120 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 121 document are to be interpreted as described in RFC 2119 [2]. 123 General mobility terminology can be found in [7]. The following 124 additional terms are used here: 126 Access Service Authorizer (ASA) 128 A network operator that authenticates a mobile node and 129 establishes the mobile node's authorization to receive Internet 130 service. 132 Access Service Provider (ASP) 134 A network operator that provides direct IP packet forwarding to 135 and from the end host. 137 Mobility Service Authorizer (MSA) 139 A service provider that authorizes Mobile IPv6 service. 141 Mobility Service Provider (MSP) 143 A service provider that provides Mobile IPv6 service. In order to 144 obtain such service, the mobile node must be authenticated and 145 prove authorization to obtain the service. 147 Split scenario 149 A scenario where mobility service and network access service are 150 authorized by different entities. This implies that MSA is 151 different from ASA. 153 3. Split scenario 155 In the problem statement description [6] there is a clear assumption 156 that mobility service and network access service can be separate. 157 This assumption implies that mobility service and network access 158 service may be authorized by different entities. As an example, the 159 service model defined in [6] allows an enterprise network to deploy a 160 Home Agent and offer Mobile IPv6 service to a user, even if the user 161 is accessing the Internet independent of its enterprise account 162 (e.g., by using his personal WiFi hotspot account at a coffee shop). 164 Therefore, in this document it is assumed that network access and 165 mobility service are authorized by different entities, which means 166 that authentication and authorization for mobility service and 167 network access will be considered separately. This scenario is 168 called split scenario. 170 Moreover, the model defined in [6] separates the entity providing the 171 service from the entity that authenticates and authorizes the user. 172 This is similar to the roaming model for network access. Therefore, 173 in the split scenario, two different cases can be identified 174 depending on the relationship between the entity that provides the 175 mobility service (i.e. Mobility Service Provider, MSP) and the 176 entity that authenticates and authorizes the user (i.e. Mobility 177 Service Authorizer, MSA). 179 Figure 1 depicts the split scenario when the MSP and the MSA are the 180 same entity. This means that the network operator that provides the 181 Home Agent authenticates and authorizes the user for mobility 182 service. 184 Mobility Service 185 Provider and Authorizer 186 +-------------------------------------------+ 187 | | 188 | +-------------+ +--+ | 189 | | MSA/MSP AAA | <-------------> |HA| | 190 | | server | AAA protocol +--+ | 191 | +-------------+ | 192 | | 193 +-------------------------------------------+ 195 +--+ 196 |MN| 197 +--+ 199 Figure 1 -- Split Scenario (MSA == MSP) 201 Figure 2 shows the split scenario in case the MSA and the MSP are two 202 different entities. This might happen if the Mobile Node is far from 203 its MSA network and is assigned a closer HA to optimize performance 204 or if the MSA cannot provide any Home Agent and relies on a third 205 party (i.e. the MSP) to grant mobility service to its users. Notice 206 that the MSP might be or might not also be the network operator that 207 is providing network access (i.e. ASP, Access Service Provider). 209 Mobility Service 210 Authorizer 211 +-------------+ 212 | MSA AAA | 213 | server | 214 +-------------+ 215 ^ 216 | 217 AAA protocol | 218 | Mobility Service 219 | Provider 220 +--------|----------------------------------+ 221 | V | 222 | +-------------+ +--+ | 223 | | MSP AAA | <-------------> |HA| | 224 | | server | AAA protocol +--+ | 225 | +-------------+ | 226 | | 227 +-------------------------------------------+ 229 +--+ 230 |MN| 231 +--+ 233 Figure 2 -- Split Scenario (MSA != MSP) 235 Note that Figure 1 and Figure 2 assume the use of an AAA protocol to 236 authenticate and authorize the Mobile Node for mobility service. 237 However, since IKEv2 allows EAP client authentication only and the 238 server authentication needs to be performed based on certificates or 239 public keys, the Mobile Node potentially requires a certificate 240 revocation list check (CRL check) even though an AAA protocol is used 241 to authenticate and authorize the Mobile Node for mobility service. 243 If, instead, PKI is used, the Mobile Node and HA use certificates to 244 authenticate each other and there is no AAA server involved [8]. 245 This is conceptually similar to Figure 1, since the MSP == MSA, 246 except the Home Agent, and potentially the Mobile Node, may require a 247 certificate revocation list check (CRL check) with the Certificate 248 Authority (CA). The CA may be either internal or external to the 249 MSP. Figure 3 illustrates this. 251 Certificate 252 Authority 253 +-------------+ 254 | CA | 255 | server | 256 +-------------+ 257 ^ 258 | 259 CRL Check | 260 | Mobility Service 261 | Provider and Authorizer 262 +--------|----------+ 263 | V | 264 | +-------------+ | 265 | | HA | | 266 | | | | 267 | +-------------+ | 268 | | 269 +-------------------+ 271 +--+ 272 |MN| 273 +--+ 275 Figure 3 -- Split Scenario with PKI 277 The split scenario is the simplest model that can be identified, 278 since no assumptions about the access network are made. This implies 279 that the mobility service is bootstrapped independently from the 280 authentication protocol for network access used (e.g. EAP or even 281 open access). For this reason, the solution described in this 282 document and developed for this scenario could also be applied to the 283 integrated access network deployment model [6], even if it might not 284 be optimized. 286 4. Components of the solution 288 The bootstrapping problem is composed of different sub-problems that 289 can be solved independently in a modular way. The components 290 identified and a brief overview of their solution follow. 292 HA address discovery 294 The Mobile Node needs to discover the address of its Home Agent. 295 The main objective of a bootstrapping solution is to minimize the 296 data pre-configured on the Mobile Node. For this reason, the 297 DHAAD defined in [1] may not be applicable in real deployments 298 since it is required that the Mobile Node is pre-configured with 299 the home network prefix and it does not allow an operator to load 300 balance by having Mobile Nodes dynamically assigned to Home Agents 301 located in different subnets. This document defines a solution 302 for Home Agent address discovery that is based on Domain Name 303 Service (DNS), introducing a new DNS SRV record [3]. The unique 304 information that needs to be pre-configured on the Mobile Node is 305 the domain name of the MSP. 307 IPsec Security Associations setup 309 Mobile IPv6 requires that a Mobile Node and its Home Agent share 310 an IPsec SA in order to protect binding updates and other Mobile 311 IPv6 signaling. This document provides a solution that is based 312 on IKEv2 and follows what is specified in [4]. The IKEv2 peer 313 authentication can be performed both using certificates and using 314 EAP, depending on the network operator's deployment model. 316 Home Address (HoA) assignment 318 The Mobile Node needs to know its Home Address in order to 319 bootstrap Mobile IPv6 operation. The Home Address is assigned by 320 the Home Agent during the IKEv2 exchange (as described in [4]). 321 The solution defined in this document also allows the Mobile Node 322 to auto-configure its Home Address based on stateless auto- 323 configuration [9], Cryptographically Generated Addresses [10] or 324 privacy addresses [11]. 326 Authentication and Authorization with MSA 328 The user must be authenticated in order for the MSP to grant the 329 service. Since the user credentials can be verified only by the 330 MSA, this authorization step is performed by the MSA. Moreover, 331 the mobility service must be explicitly authorized by the MSA 332 based on the user's profile. These operations are performed in 333 different ways depending on the credentials used by the Mobile 334 Node during the IKEv2 peer authentication and on the backend 335 infrastructure (PKI or AAA). 337 An optional part of bootstrapping involves providing a way for the 338 Mobile Node to have its FQDN updated in the DNS with a dynamically 339 assigned home address. While not all applications will require this 340 service, many networking applications use the FQDN to obtain an 341 address for a node prior to starting IP traffic with it. The 342 solution defined in this document specifies that the dynamic DNS 343 update is performed by the Home Agent or through the AAA 344 infrastructure, depending on the trust relationship in place. 346 5. Protocol Operations 348 This section describes in detail the procedures needed to perform 349 Mobile IPv6 bootstrapping based on the components identified in the 350 previous section. 352 5.1. Home Agent Address Discovery 354 Once a Mobile Node has obtained network access, it can perform Mobile 355 IPv6 bootstrapping. For this purpose, the Mobile Node queries the 356 DNS server to request information on Home Agent service. As 357 mentioned before in the document, the Mobile Node should be pre- 358 configured with the domain name of the Mobility Service Provider. 360 The Mobile Node needs to obtain the IP address of a DNS server before 361 it can send a DNS request. This can be configured on the Mobile Node 362 or obtained through DHCPv6 from the visited link [12]. In any case, 363 it is assumed that there is some kind of mechanism by which the 364 Mobile Node is configured with a DNS server since a DNS server is 365 needed for many other reasons. 367 Two options for DNS lookup for a Home Agent address are identified in 368 this document: DNS lookup by Home Agent Name and DNS lookup by 369 service name. 371 This document does not provide a specific mechanism to load balance 372 different Mobile Nodes among Home Agents. It is possible for an MSP 373 to achieve coarse-grained load balancing by dynamically updating the 374 SRV RR priorities to reflect the current load on the MSP's collection 375 of Home Agents. Mobile Nodes then use the priority mechanism to 376 preferentially select the least loaded HA. The effectiveness of this 377 technique depends on how much of a load it will place on the DNS 378 servers, particularly if dynamic DNS is used for frequent updates. 380 While this document specifies a Home Agent Address Discovery solution 381 based on DNS, when the ASP and the MSP are the same entity DHCP may 382 be used. See [13] for details. 384 5.1.1. DNS lookup by Home Agent Name 386 In this case, the Mobile Node is configured with the Fully Qualified 387 Domain Name of the Home Agent. As an example, the Mobile Node could 388 be configured with the name "ha1.example.com", where "example.com" is 389 the domain name of the MSP granting the mobility service. 391 The Mobile Node constructs a DNS request, by setting the QNAME to the 392 name of the Home Agent. The request has QTYPE set to 'AAAA', so that 393 the DNS server sends the IPv6 address of the Home Agent. Once the 394 DNS server replies to this query, the Mobile Node knows its Home 395 Agent address and can run IKEv2 in order to set up the IPsec SAs and 396 get a Home Address. 398 Note that the configuration of a home agent FQDN on the mobile node 399 can also be extended to dynamically assign a local home agent from 400 the visited network. Such dynamic assignment would be useful, for 401 instance, from the point of view of improving routing efficiency in 402 bidirectional tunneling mode. Enhancements or conventions for 403 dynamic assignment of local home agents are outside the scope of this 404 specification. 406 5.1.2. DNS lookup by service name 408 RFC 2782 [3] defines the service resource record (SRV RR) that allows 409 an operator to use several servers for a single domain, to move 410 services from host to host, and to designate some hosts as primary 411 servers for a service and others as backups. Clients ask for a 412 specific service/protocol for a specific domain and get back the 413 names of any available servers. 415 RFC 2782 [3] also describes the policies to choose a service agent 416 based on the preference and weight values. The DNS SRV record may 417 contain the preference and weight values for multiple Home Agents 418 available to the Mobile Node in addition to the Home Agent FQDNs. If 419 multiple Home Agents are available in the DNS SRV record then Mobile 420 Node is responsible for processing the information as per policy and 421 for picking one Home Agent. If the Home Agent of choice does not 422 respond to the IKE_SA_INIT messages or if IKEv2 authentication fails, 423 the Mobile Node SHOULD try the next Home Agent on the list. If none 424 of the Home Agents respond, the Mobile Node SHOULD try again after a 425 period of time that is configurable on the Mobile Node. If IKEv2 426 authentication fails with all Home Agents, it is an unrecoverable 427 error on the Mobile Node. 429 The service name for Mobile IPv6 Home Agent service as required by 430 RFC 2782 is "mip6" and the protocol name is "ipv6". Note that a 431 transport name cannot be used here because Mobile IPv6 does not run 432 over a transport protocol. 434 The SRV RR has a DNS type code of 33. As an example, the Mobile 435 constructs a request with QNAME set to "_mip6._ipv6.example.com" and 436 QTYPE to SRV. The reply contains the FQDNs of one or more servers, 437 that can then be resolved in a separate DNS transaction to the IP 438 addresses. However, if there is room in the SRV reply, it is 439 RECOMMENDED that the DNS server also return the IP addresses of the 440 Home Agents in AAAA records as part of the additional data section 441 (in order to avoid requiring an additional DNS round trip to resolve 442 the FQDNs). 444 5.2. IPsec Security Associations setup 446 As soon as the Mobile Node has discovered the Home Agent Address, it 447 establishes an IPsec Security Association with the Home Agent itself 448 through IKEv2. The detailed description of this procedure is 449 provided in [4]. If the Mobile Node wants the HA to register the 450 Home Address in the DNS, it MUST use the FQDN as the initiator 451 identity in IKE_AUTH step of the IKEv2 exchange (IDi). This is 452 needed because the Mobile Node has to prove it is the owner of the 453 FQDN provided in the subsequent DNS Update Option. See section 6 and 454 section 9 for a more detailed analysis on this issue. 456 The IKEv2 Mobile Node to Home Agent authentication can be performed 457 using either IKEv2 public key signatures or the Extensible 458 Authentication Protocol (EAP). The details about how to use IKEv2 459 authentication are described in [4] and [5]. Choice of an IKEv2 peer 460 authentication method depends on the deployment. The Mobile Node 461 should be configured with the information on which IKEv2 462 authentication method to use. However, IKEv2 restricts the Home 463 Agent to Mobile Node authentication to use public key signature-based 464 authentication. 466 5.3. Home Address assignment 468 Home Address assignment is performed during the IKEv2 exchange. The 469 Home Address can be assigned directly by the Home Agent or can be 470 auto-configured by the Mobile Node. 472 5.3.1. Home Address assignment by the Home Agent 474 When the Mobile Node runs IKEv2 with its Home Agent, it can request a 475 HoA through the Configuration Payload in the IKE_AUTH exchange by 476 including an INTERNAL_IP6_ADDRESS attribute. When the Home Agent 477 processes the message, it allocates a HoA and sends it a CFG_REPLY 478 message. The Home Agent could consult a DHCP server on the home link 479 for the actual home address allocation. This is explained in detail 480 in [4]. 482 5.3.2. Home Address auto-configuration by the Mobile Node 484 With the type of assignment described in the previous section, the 485 Home Address cannot be generated based on Cryptographically Generated 486 Addresses (CGAs) [10] or based on the privacy extensions for 487 stateless auto-configuration [11]. However, the Mobile Node might 488 want to have an auto-configured HoA based on these mechanisms. It is 489 worthwhile to mention that the auto-configuration procedure described 490 in this section cannot be used in some possible deployments, since 491 the Home Agents might be provisioned with pools of allowed Home 492 Addresses. 494 In the simplest case, the Mobile Node is provided with a pre- 495 configured home prefix and home prefix length. In this case the 496 Mobile Node creates a Home Address based on the pre-configured prefix 497 and sends it to the Home Agent including an INTERNAL_IP6_ADDRESS 498 attribute in a Configuration Payload of type CFG_REQUEST. If the 499 Home Address is valid, the Home Agent replies with a CFG_REPLY, 500 including an INTERNAL_IP6_ADDRESS with the same address. If the Home 501 Address provided by the Mobile Node is not valid, the Home Agent 502 assigns a different Home Address including an INTERNAL_IP6_ADDRESS 503 attribute with a new value. According to [5] the Mobile Node MUST 504 use the address sent by the Home Agent. Later, if the Mobile Node 505 wants to use an auto-configured Home Address (e.g. based on CGA), it 506 can run Mobile Prefix Discovery, obtain a prefix, auto-configure a 507 new Home Address and then perform a new CREATE_CHILD_SA exchange. 509 If the Mobile Node is not provided with a pre-configured Home Prefix, 510 the Mobile cannot simply propose an auto-configured HoA in the 511 Configuration Payload since the Mobile Node does not know the home 512 prefix before the start of the IKEv2 exchange. The Mobile Node must 513 obtain the home prefix and the home prefix length before it can 514 configure a home address. 516 One simple solution would be for the Mobile Node to just assume that 517 the prefix length on the home link is 64 bits and extract the home 518 prefix from the Home Agent's address. The disadvantage with this 519 solution is that the home prefix cannot be anything other than /64. 520 Moreover, this ties the prefix on the home link and the Home Agent's 521 address, but, in general, a Home Agent with a particular address 522 should be able to serve a number of prefixes on the home link, not 523 just the prefix from which its address is configured. 525 Another solution would be for the Mobile Node to assume that the 526 prefix length on the home link is 64 bits and send its interface 527 identifier to the Home Agent in the INTERNAL_IP6_ADDRESS attribute 528 within the CFG_REQ payload. Even though this approach does not tie 529 the prefix on the home link and the Home Agent's address, it still 530 requires that the home prefix length is 64 bits. 532 For this reason the Mobile Node needs to obtain the home link 533 prefixes through the IKEv2 exchange. In the Configuration Payload 534 during the IKE_AUTH exchange, the Mobile Node includes the 535 MIP6_HOME_PREFIX attribute in the CFG_REQUEST message. The Home 536 Agent, when it processes this message, MUST include in the CFG_REPLY 537 payload prefix information for one prefix on the home link. This 538 prefix information includes the prefix length (see Section 8.2). The 539 Mobile Node auto-configures a Home Address from the prefix returned 540 in the CFG_REPLY message and runs a CREATE_CHILD_SA exchange to 541 create security associations for the new Home Address. 543 As mentioned before in this document, there are deployments where 544 auto-configuration of the Home Address cannot be used. In this case, 545 when the Home Agent receives a CFG_REQUEST including a 546 MIP6_HOME_PREFIX attribute, in the subsequent IKE response it 547 includes a Notify Payload type "USE_ASSIGNED_HoA" and the related 548 Home Address in a INTERNAL_IP6_ADDRESS attribute. If the Mobile Node 549 gets a "USE_ASSIGNED_HoA" Notify Payload in response to the 550 Configuration Payload containing the MIP6_HOME_PREFIX attribute, it 551 looks for an INTERNAL_IP6_ADDRESS attribute and MUST use the address 552 contained in it in the subsequent CREATE_CHILD_SA exchange. 554 When the Home Agent receives a Binding Update for the Mobile Node, it 555 performs proxy DAD for the auto-configured Home Address. If DAD 556 fails, the Home Agent rejects the Binding Update. If the Mobile Node 557 receives a Binding Acknowledgement with status 134 (DAD failed), it 558 MUST stop using the current Home Address, configure a new HoA, and 559 then run IKEv2 CREATE_CHILD_SA exchange to create security 560 associations based on the new HoA. The Mobile Node does not need to 561 run IKE_INIT and IKE_AUTH exchanges again. Once the necessary 562 security associations are created, the Mobile Node sends a Binding 563 Update for the new Home Address. 565 It is worth noting that with this mechanism, the prefix information 566 carried in MIP6_HOME_PREFIX attribute includes only one prefix and 567 does not carry all the information that is typically present when 568 received through a IPv6 router advertisement. Mobile Prefix 569 Discovery, specified in RFC 3775, is the mechanism through which the 570 Mobile Node can get all prefixes on the home link and all related 571 information. That means that MIP6_HOME_PREFIX attribute is only used 572 for Home Address auto-configuration and does not replace the usage of 573 Mobile Prefix Discovery for the purposes detailed in RFC 3775. 575 5.4. Authorization and Authentication with MSA 577 In a scenario where the Home Agent is discovered dynamically by the 578 Mobile Node, it is very likely that the Home Agent is not able to 579 verify by its own the credentials provided by the Mobile Node during 580 the IKEv2 exchange. Moreover, the mobility service needs to be 581 explicitly authorized based on the user's profile. As an example, 582 the Home Agent might not be aware of whether the mobility service can 583 be granted at a particular time of the day or when the credit of the 584 Mobile Node is going to expire. 586 Due to all these reasons, the Home Agent may need to contact the MSA 587 in order to authenticate the Mobile Node and authorize mobility 588 service. This can be accomplished based on a Public Key 589 Infrastructure if certificates are used and a PKI is deployed by the 590 MSP and MSA. On the other hand, if the Mobile Node is provided with 591 other types of credentials, the AAA infrastructure must be used. 593 The definition of this backend communication is out of the scope of 594 this document. In [14] a list of goals for such a communication is 595 provided. [15] and [16] define the RADIUS and Diameter extensions, 596 respectively, for the backend communication. 598 6. Home Address registration in the DNS 600 In order that the Mobile Node is reachable through its dynamically 601 assigned Home Address, the DNS needs to be updated with the new Home 602 Address. Since applications make use of DNS lookups on FQDN to find 603 a node, the DNS update is essential for providing IP reachability to 604 the Mobile Node, which is the main purpose of the Mobile IPv6 605 protocol. The need for DNS updating is not discussed in RFC 3775 606 since it assumes that the Mobile Node is provisioned with a static 607 Home Address. However, when a dynamic Home Address is assigned to 608 the Mobile Node, any existing DNS entry becomes invalid and the 609 Mobile Node becomes unreachable unless a DNS update is performed. 611 Since the DNS update must be performed securely in order to prevent 612 attacks or modifications from malicious nodes, the node performing 613 this update must share a security association with the DNS server. 614 Having all possible Mobile Nodes sharing a security association with 615 the DNS servers of the MSP might be cumbersome from an administrative 616 perspective. Moreover, even if a Mobile Node has a security 617 association with a DNS server of its MSP, an address authorization 618 issue comes into the picture. A detailed analysis of possible 619 threats against DNS update is provided in Section 9.5. 621 Therefore, due to security and administrative reasons, it is 622 RECOMMENDED that the Home Agent perform DNS entry updates for the 623 Mobile Node. For this purpose the Mobile Node MAY include a new 624 mobility option in the Binding Update, the DNS Update option, with 625 the flag R not set in the option. This option is defined in 626 Section 8 and includes the FQDN that needs to be updated. After 627 receiving the Binding Update, the Home Agent MUST update the DNS 628 entry with the identifier provided by the Mobile Node and the Home 629 Address included in the Home Address Option. The procedure for 630 sending a dynamic DNS update message is specified in [17]. The 631 dynamic DNS update SHOULD be performed in a secure way; for this 632 reason, the usage of TKEY and TSEC or DNSSEC is recommended (see 633 Section 9.5 for details). As soon as the Home Agent has updated the 634 DNS, it MUST send a Binding Acknowledgement message to the Mobile 635 Node including the DNS Update mobility option with the correct value 636 in the Status field (see Section 8.1). 638 This procedure can be performed directly by the Home Agent if the 639 Home Agent has a security association with the domain specified in 640 the Mobile Node's FQDN. 642 On the other hand, if the Mobile Node wants to be reachable through a 643 FQDN that belongs to the MSA, the Home Agent and the DNS server that 644 must be updated belong to different administrative domains. In this 645 case the Home Agent may not share a security association with the DNS 646 server and the DNS entry update can be performed by the AAA server of 647 the MSA. In order to accomplish this, the Home Agent sends to the 648 AAA server the FQDN-HoA pair through the AAA protocol. This message 649 is proxied by the AAA infrastructure of the MSP and is received by 650 the AAA server of the MSA. The AAA server of the MSA perform the DNS 651 update based on [17]. Notice that, even in this case, the Home Agent 652 is always required to perform a DNS update for the reverse entry, 653 since this is always performed in the DNS server of the MSP. The 654 detailed description of the communication between Home Agent and AAA 655 is out of the scope of this document. More details are provided in 656 [14]. 658 A mechanism to remove stale DNS entries is needed. A DNS entry 659 becomes stale when the related Home Address is no longer used by the 660 Mobile Node. To remove a DNS entry, the Mobile Node includes in the 661 Binding Update the DNS Update mobility option, with the flag R set in 662 the option. After receiving the Binding Update, the Home Agent MUST 663 remove the DNS entry identified by the FQDN provided by the Mobile 664 Node and the Home Address included in the Home Address Option. The 665 procedure for sending a dynamic DNS update message is specified in 666 [17]. As mentioned above, the dynamic DNS update SHOULD be performed 667 in a secure way; for this reason, the usage of TKEY and TSEC or 668 DNSSEC is recommended (see Section 9.5 for details). 670 If there is no explicit de-registration BU from the Mobile Node, then 671 the HA MAY use the binding cache entry expiration as a trigger to 672 remove the DNS entry. 674 7. Summary of Bootstrapping Protocol Flow 676 The message flow of the whole bootstrapping procedure when the 677 dynamic DNS update is performed by the Home Agent is depicted below. 679 +----+ +----+ +-----+ 680 | MN | | HA | | DNS | 681 +----+ +----+ +-----+ 683 IKEv2 exchange 684 (HoA configuration) 685 <======================> 687 BU (DNS update option) 688 -----------------------> 689 DNS update 690 <-------------------> 691 BA (DNS update option) 692 <----------------------- 694 On the contrary, the figure below shows the message flow of the whole 695 bootstrapping procedure when the dynamic DNS update is performed by 696 the AAA server of the MSA. 698 +----+ +----+ +---+ +---+ 699 | MN | | HA | |AAA| |DNS| 700 +----+ +----+ +---+ +---+ 702 IKEv2 exchange 703 (HoA configuration) 704 <======================> 706 BU (DNS update option) 707 -----------------------> 709 AAA request 710 (FQDN, HoA) 711 <--------------> 713 DNS update 714 <-----------> 715 AAA answer 716 (FQDN, HoA) 717 <--------------> 718 BA (DNS update option) 719 <----------------------- 721 Notice that, even in this last case, the Home Agent is always 722 required to perform a DNS update for the reverse entry, since this is 723 always performed in the DNS server of the MSP. This is not depicted 724 in the figure above. 726 8. Option and Attribute Format 728 8.1. DNS Update mobility option 730 0 1 2 3 731 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 1 732 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 733 | Option Type | Option Length | 734 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 735 | Status |R| Reserved | MN identity (FQDN) ... 736 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 738 Option Type 740 DNS-UPDATE-TYPE to be defined by IANA 742 Option Length 744 8-bit unsigned integer indicating the length of the option 745 excluding the type and length fields 747 Status 749 8-bit unsigned integer indicating the result of the dynamic DNS 750 update procedure. This field MUST be set to 0 and ignored by the 751 receiver when the DNS Update mobility option is included in a 752 Binding Update message. When the DNS Update mobility option is 753 included in the Binding Acknowledgement message, values of the 754 Status field less than 128 indicate that the dynamic DNS update 755 was performed successfully by the Home Agent. Values greater than 756 or equal to 128 indicate that the dynamic DNS update was not 757 completed by the HA. The following Status values are currently 758 defined: 760 0 DNS update performed 762 128 Reason unspecified 764 129 Administratively prohibited 765 130 DNS Update Failed 767 R flag 769 If set the Mobile Node is requesting the HA to remove the DNS 770 entry identified by the FQDN specified in this option and the HoA 771 of the Mobile Node. If not set, the Mobile Node is requesting the 772 HA to create or update a DNS entry with its HoA and the FQDN 773 specified in the option 775 Reserved 777 MUST be set to 0 779 MN identity 781 The identity of the Mobile Node in FQDN format to be used by the 782 Home Agent to send a Dynamic DNS update. It is a variable length 783 field 785 8.2. MIP6_HOME_PREFIX attribute 787 0 1 2 3 788 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 1 789 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 790 |R| Attribute Type | 791 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 792 | Length | Prefix Length | 793 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 794 | | 795 | home prefix | 796 | | 797 | | 798 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 799 | Prefix Lifetime | 800 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 802 Reserved (1 bit) 804 This bit MUST be set to zero and MUST be ignored on receipt 806 Attribute Type (15 bits) 808 A unique identifier for the MIP6_HOME_PREFIX attribute. To be 809 assigned by IANA 811 Length (2 octets) 813 Length in octets of Value field (home prefix and Prefix Length). 814 This is multi-valued and can be 0 or 17 816 Prefix Length (2 octets) 818 The length in bits of the home prefix specified in the field Home 819 Prefix 821 Home Prefix (16 octets) 823 The prefix of the home link through which the Mobile Node may 824 auto-configure its Home Address 826 Prefix Lifetime (4 octets) 828 The lifetime of the Home Prefix 830 When the MIP6_HOME_PREFIX attribute is included by the Mobile Node in 831 the CFG_REQUEST payload, the value of the Length field is 0. On the 832 other hand, when the MIP6_HOME_PREFIX attribute is included in the 833 CFG_REPLY payload by the Home Agent, the value of the Length field is 834 17 and the attribute contains also the Home Prefix and the Prefix 835 Length fields. 837 9. Security Considerations 839 9.1. HA Address Discovery 841 Use of DNS for address discovery carries certain security risks. DNS 842 transactions in the Internet are typically done without any 843 authentication of the DNS server by the client or of the client by 844 the server. There are two risks involved: 846 1. A legitimate client obtains a bogus Home Agent address from a 847 bogus DNS server. This is sometimes called a "pharming" attack, 849 2. An attacking client obtains a legitimate Home Agent address from 850 a legitimate server. 852 The risk in Case 1 is mitigated because the Mobile Node is required 853 to conduct an IKE transaction with the Home Agent prior to performing 854 a Binding Update to establish Mobile IPv6 service. According to the 855 IKEv2 specification [5], the responder must present the initiator 856 with a valid certificate containing the responder's public key, and 857 the responder to initiator IKE_AUTH message must be protected with an 858 authenticator calculated using the public key in the certificate. 859 Thus, an attacker would have to set up both a bogus DNS server and a 860 bogus Home Agent, and provision the Home Agent with a certificate 861 that a victim Mobile Node could verify. If the Mobile Node can 862 detect that the certificate is not trustworthy, the attack will be 863 foiled when the Mobile Node attempts to set up the IKE SA. 865 The risk in Case 2 is limited for a single Mobile Node to Home Agent 866 transaction if the attacker does not possess proper credentials to 867 authenticate with the Home Agent. The IKE SA establishment will fail 868 when the attacking Mobile Node attempts to authenticate itself with 869 the Home Agent. Regardless of whether the Home Agent utilizes EAP or 870 host-side certificates to authenticate the Mobile Node, the 871 authentication will fail unless the Mobile Node has valid 872 credentials. 874 Another risk exists in Case 2 because the attacker may be attempting 875 to propagate a DoS attack on the Home Agent. In that case, the 876 attacker obtains the Home Agent address from the DNS, then propagates 877 the address to a network of attacking hosts that bombard the Home 878 Agent with traffic. This attack is not unique to the bootstrapping 879 solution, however, it is actually a risk that any Mobile IPv6 Home 880 Agent installation faces. In fact, the risk is faced by any service 881 in the Internet that distributes a unicast globally routable address 882 to clients. Since Mobile IPv6 requires that the Mobile Node 883 communicate through a globally routable unicast address of a Home 884 Agent, it is possible that the Home Agent address could be propagated 885 to an attacker by various means (theft of the Mobile Node, malware 886 installed on the Mobile Node, evil intent of the Mobile Node owner 887 him/herself, etc.) even if the home address is manually configured on 888 the Mobile Node. Consequently, every Mobile IPv6 Home Agent 889 installation will likely be required to mount anti-DoS measures. 890 Such measures include overprovisioning of links to and from Home 891 Agents and of Home Agent processing capacity, vigilant monitoring of 892 traffic on the Home Agent networks to detect when traffic volume 893 increases abnormally indicating a possible DoS attack, and hot spares 894 that can quickly be switched on in the event an attack is mounted on 895 an operating collection of Home Agents. DoS attacks of moderate 896 intensity should be foiled during the IKEv2 transaction. IKEv2 897 implementations are expected to generate their cookies without any 898 saved state, and to time out cookie generation parameters frequently, 899 with the timeout value increasing if a DoS attack is suspected. This 900 should prevent state depletion attacks, and should assure continued 901 service to legitimate clients until the practical limits on the 902 network bandwidth and processing capacity of the Home Agent network 903 are reached. 905 Explicit security measures between the DNS server and host, such 906 DNSSEC [18] or TSIG/TKEY [19] [20] can mitigate the risk of 1) and 907 2), but these security measures are not widely deployed on end nodes. 908 These security measures are not sufficient to protect the Home Agent 909 address against DoS attack, however, because a node having a 910 legitimate security association with the DNS server could 911 nevertheless intentionally or inadvertently cause the Home Agent 912 address to become the target of DoS. 914 Finally notice that assignment of an home agent from the serving 915 network access provider's (local home agent) or a home agent from a 916 nearby network (nearby home agent) may set up the potential to 917 compromise a mobile node's location privacy. A home address anchored 918 at such home agent contains some information about the topological 919 location of the mobile node. Consequently, a mobile node requiring 920 location privacy should not disclose this home address to nodes that 921 are not authorized to learn the mobile node's location, e.g., by 922 updating DNS with the new home address. 924 Security considerations for discovering HA using DHCP are covered in 925 [21]. 927 9.2. Home Address Assignment through IKEv2 929 Mobile IPv6 bootstrapping assigns the home address through the IKEv2 930 transaction. The Mobile Node can either choose to request an 931 address, similar to DHCP, or the Mobile Node can request a prefix on 932 the home link then auto-configure an address. 934 RFC 3775 [1] requires that a Home Agent check authorization of a home 935 address received during a Binding Update. Therefore, the home agent 936 MUST authorize each home address allocation and use. This 937 authorization is based on linking the mobile node identity used in 938 the IKEv2 authentication process and the home address. Home agents 939 MUST implement at least the following two modes of authorization: 941 o Configured home address(es) for each mobile node. In this mode, 942 the home agent or infrastructure nodes behind it know what 943 addresses a specific mobile node is authorized to use. The mobile 944 node is allowed to request these addresses, or if the mobile node 945 requests any home address, these addresses are returned to it. 947 o First-come-first-served (FCFS). In this mode, the home agent 948 maintains a pool of "used" addresses, and allows mobile nodes to 949 request any address, as long as it is not used by another mobile 950 node. 952 Addresses MUST be marked as used for at least as long as the binding 953 exists, and are associated with the identity of the mobile node that 954 made the allocation. 956 In addition, the home agent MUST ensure that the requested address is 957 not the authorized address of any other mobile node, if both FCFS and 958 configured modes use the same address space. 960 9.3. SA Establishment Using EAP Through IKEv2 962 Security considerations for authentication of the IKE transaction 963 using EAP are covered in [4] . 965 9.4. Back End Security Between the HA and AAA Server 967 Some deployments of Mobile IPv6 bootstrapping may use an AAA server 968 to handle authorization for mobility service. This process has its 969 own security requirements, but the back end protocol for Home Agent 970 to AAA server interface is not covered in this draft. Please see 971 [14] for a discussion of this interface. 973 9.5. Dynamic DNS Update 975 If a Home Agent performs dynamic DNS update on behalf of the Mobile 976 Node directly with the DNS server, the Home Agent MUST have a 977 security association of some type with the DNS server. The security 978 association MAY be established either using DNSSEC [18] or TSIG/TKEY 979 [19][20]. A security association is REQUIRED even if the DNS server 980 is in the same administrative domain as the Home Agent. The security 981 association SHOULD be separate from the security associations used 982 for other purposes, such as AAA. 984 In the case where the Mobility Service Provider is different from the 985 Mobility Service Authorizer, the network administrators may want to 986 limit the number of cross-administrative domain security 987 associations. If the Mobile Node's FQDN is in the Mobility Service 988 Authorizer's domain, since a security association for AAA signaling 989 involved in mobility service authorization is required in any case, 990 the Home Agent can send the Mobile Node's FQDN to the AAA server 991 under the HA-AAA server security association, and the AAA server can 992 perform the update. In that case, a security association is required 993 between the AAA server and DNS server for the dynamic DNS update. 994 See [14] for a deeper discussion of the Home Agent to AAA server 995 interface. 997 Regardless of whether the AAA server or Home Agent performs DNS 998 update, the authorization of the Mobile Node to update a FQDN MUST be 999 checked prior to the performance of the update. It is an 1000 implementation issue as to how authorization is determined. However, 1001 in order to allow this authorization step, the Mobile Node MUST use a 1002 FQDN as the IDi in IKE_AUTH step of the IKEv2 exchange. The FQDN 1003 MUST be the same that will be provided by the Mobile Node in the DNS 1004 Update Option. 1006 In case EAP over IKEv2 is used to set-up the IPsec SA, the Home Agent 1007 gets authorization information about the Mobile Node's FQDN via the 1008 AAA back end communication performed during IKEv2 exchange. The 1009 outcome of this step will give the Home Agent the necessary 1010 information to authorize the DNS update request of the Mobile Node. 1011 See [14] for details about the communication between the AAA server 1012 and the Home Agent needed to perform the authorization. 1014 In case certificates are used in IKEv2, the authorization information 1015 about the FQDN for DNS update MUST be present in the certificate 1016 provided by the Mobile Node. Since the IKEv2 specification does not 1017 include a required certificate type, it is not possible to specify 1018 precisely how the Mobile Node's FQDN should appear in the 1019 certificate. However, as an example, if the certificate type is 1020 "X.509 Certificate - Signature" (one of the recommended types) then 1021 the FQDN may appear in the subjectAltName attribute extension [22]. 1023 10. IANA Considerations 1025 This document defines a new Mobility Option and a new IKEv2 1026 Configuration Attribute Type. 1028 The following values should be assigned: 1030 o from "Mobility Option" namespace ([1]): DNS-UPDATE-TYPE 1031 (Section 8.1) 1033 o from "IKEv2 Configuration Payload Attribute Types" namespace 1034 ([5]): MIP6_HOME_PREFIX attribute (Section 8.2) 1036 o from "IKEv2 Notify Payload Error Types" namespace ([5]): 1037 USE_ASSIGNED_HoA error type (Section 5.3.2) 1039 11. Contributors 1041 This contribution is a joint effort of the bootstrapping solution 1042 design team of the MIP6 WG. The contributors include Basavaraj 1043 Patil, Alpesh Patel, Jari Arkko, James Kempf, Yoshihiro Ohba, Gopal 1044 Dommety, Alper Yegin, Junghoon Jee, Vijay Devarapalli, Kuntal 1045 Chowdury, Julien Bournelle. 1047 The design team members can be reached at: 1049 Gerardo Giaretta gerardog@qualcomm.com 1051 Basavaraj Patil basavaraj.patil@nokia.com 1053 Alpesh Patel alpesh@cisco.com 1055 Jari Arkko jari.arkko@kolumbus.fi 1057 James Kempf kempf@docomolabs-usa.com 1059 Yoshihiro Ohba yohba@tari.toshiba.com 1061 Gopal Dommety gdommety@cisco.com 1063 Alper Yegin alper.yegin@samsung.com 1065 Vijay Devarapalli vijay.devarapalli@azairenet.com 1067 Kuntal Chowdury kchowdury@starentnetworks.com 1069 Junghoon Jee jhjee@etri.re.kr 1071 Julien Bournelle julien.bournelle@gmail.com 1073 12. Acknowledgements 1075 The authors would like to thank Rafa Lopez, Francis Dupont, Jari 1076 Arkko, Kilian Weniger, Vidya Narayanan, Ryuji Wakikawa, Michael Ye 1077 for their valuable comments. 1079 13. References 1081 13.1. Normative References 1083 [1] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in 1084 IPv6", RFC 3775, June 2004. 1086 [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement 1087 Levels", BCP 14, RFC 2119, March 1997. 1089 [3] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for 1090 specifying the location of services (DNS SRV)", RFC 2782, 1091 February 2000. 1093 [4] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with 1094 IKEv2 and the Revised IPsec Architecture", RFC 4877, 1095 April 2007. 1097 [5] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", 1098 RFC 4306, December 2005. 1100 13.2. Informative References 1102 [6] Patel, A. and G. Giaretta, "Problem Statement for bootstrapping 1103 Mobile IPv6 (MIPv6)", RFC 4640, September 2006. 1105 [7] Manner, J. and M. Kojo, "Mobility Related Terminology", 1106 RFC 3753, June 2004. 1108 [8] Adams, C., Farrell, S., Kause, T., and T. Mononen, "Internet 1109 X.509 Public Key Infrastructure Certificate Management Protocol 1110 (CMP)", RFC 4210, September 2005. 1112 [9] Narten, T., "Neighbor Discovery for IP version 6 (IPv6)", 1113 draft-ietf-ipv6-2461bis-11 (work in progress), March 2007. 1115 [10] Aura, T., "Cryptographically Generated Addresses (CGA)", 1116 RFC 3972, March 2005. 1118 [11] Narten, T. and R. Draves, "Privacy Extensions for Stateless 1119 Address Autoconfiguration in IPv6", RFC 3041, January 2001. 1121 [12] Droms, R., "DNS Configuration options for Dynamic Host 1122 Configuration Protocol for IPv6 (DHCPv6)", RFC 3646, 1123 December 2003. 1125 [13] Chowdhury, K. and A. Yegin, "MIP6-bootstrapping for the 1126 Integrated Scenario", 1127 draft-ietf-mip6-bootstrapping-integrated-dhc-04 (work in 1128 progress), June 2007. 1130 [14] Giaretta, G., "AAA Goals for Mobile IPv6", 1131 draft-ietf-mip6-aaa-ha-goals-03 (work in progress), 1132 September 2006. 1134 [15] Chowdhury, K., "RADIUS Mobile IPv6 Support", 1135 draft-ietf-mip6-radius-02 (work in progress), March 2007. 1137 [16] Bournelle, J., "Diameter Mobile IPv6: HA <-> HAAA Support", 1138 draft-ietf-dime-mip6-split-02 (work in progress), May 2007. 1140 [17] Vixie, P., Thomson, S., Rekhter, Y., and J. Bound, "Dynamic 1141 Updates in the Domain Name System (DNS UPDATE)", RFC 2136, 1142 April 1997. 1144 [18] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, 1145 "DNS Security Introduction and Requirements", RFC 4033, 1146 March 2005. 1148 [19] Vixie, P., Gudmundsson, O., Eastlake, D., and B. Wellington, 1149 "Secret Key Transaction Authentication for DNS (TSIG)", 1150 RFC 2845, May 2000. 1152 [20] Eastlake, D., "Secret Key Establishment for DNS (TKEY RR)", 1153 RFC 2930, September 2000. 1155 [21] Jang, H., "DHCP Option for Home Information Discovery in 1156 MIPv6", draft-ietf-mip6-hiopt-05 (work in progress), June 2007. 1158 [22] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet X.509 1159 Public Key Infrastructure Certificate and Certificate 1160 Revocation List (CRL) Profile", RFC 3280, April 2002. 1162 Authors' Addresses 1164 Gerardo Giaretta 1165 Qualcomm 1167 Email: gerardog@qualcomm.com 1169 James Kempf 1170 DoCoMo Labs USA 1171 181 Metro Drive 1172 San Jose, CA 95110 1173 USA 1175 Email: kempf@docomolabs-usa.com 1177 Vijay Devarapalli 1178 Azaire Networks 1179 3121 Jay Street 1180 Santa Clara, CA 95054 1181 USA 1183 Email: vijay.devarapalli@azairenet.com 1185 Full Copyright Statement 1187 Copyright (C) The IETF Trust (2007). 1189 This document is subject to the rights, licenses and restrictions 1190 contained in BCP 78, and except as set forth therein, the authors 1191 retain all their rights. 1193 This document and the information contained herein are provided on an 1194 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 1195 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 1196 THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 1197 OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 1198 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 1199 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 1201 Intellectual Property 1203 The IETF takes no position regarding the validity or scope of any 1204 Intellectual Property Rights or other rights that might be claimed to 1205 pertain to the implementation or use of the technology described in 1206 this document or the extent to which any license under such rights 1207 might or might not be available; nor does it represent that it has 1208 made any independent effort to identify any such rights. Information 1209 on the procedures with respect to rights in RFC documents can be 1210 found in BCP 78 and BCP 79. 1212 Copies of IPR disclosures made to the IETF Secretariat and any 1213 assurances of licenses to be made available, or the result of an 1214 attempt made to obtain a general license or permission for the use of 1215 such proprietary rights by implementers or users of this 1216 specification can be obtained from the IETF on-line IPR repository at 1217 http://www.ietf.org/ipr. 1219 The IETF invites any interested party to bring to its attention any 1220 copyrights, patents or patent applications, or other proprietary 1221 rights that may cover technology that may be required to implement 1222 this standard. Please address the information to the IETF at 1223 ietf-ipr@ietf.org. 1225 Acknowledgment 1227 Funding for the RFC Editor function is provided by the IETF 1228 Administrative Support Activity (IASA).