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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) No issues found here. Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group D. Migault (Ed) 3 Internet-Draft Ericsson 4 Intended status: Standards Track V. Smyslov 5 Expires: June 5, 2016 ELVIS-PLUS 6 December 3, 2015 8 Cloning IKE SA in the Internet Key Exchange Protocol Version 2 (IKEv2) 9 draft-mglt-ipsecme-clone-ike-sa-08.txt 11 Abstract 13 This document considers a VPN End User establishing an IPsec SA with 14 a Security Gateway using the Internet Key Exchange Protocol Version 2 15 (IKEv2), where at least one of the peers has multiple interfaces or 16 where Security Gateway is a cluster with each node having its own IP 17 address. 19 The protocol described allows a peer to clone an IKEv2 SA, where an 20 additional SA is derived from an existing one. The newly created IKE 21 SA is set without the IKEv2 authentication exchange. This IKE SA can 22 later be assigned to another interface or moved to another cluster 23 node. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at http://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on June 5, 2016. 42 Copyright Notice 44 Copyright (c) 2015 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (http://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 Table of Contents 59 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 2 60 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 61 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 62 4. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 5 63 5. Protocol Details . . . . . . . . . . . . . . . . . . . . . . 6 64 5.1. Support Negotiation . . . . . . . . . . . . . . . . . . . 6 65 5.2. Cloning the IKE SA . . . . . . . . . . . . . . . . . . . 6 66 5.3. Error Handling . . . . . . . . . . . . . . . . . . . . . 7 67 6. Payload Description . . . . . . . . . . . . . . . . . . . . . 7 68 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 69 8. Security Considerations . . . . . . . . . . . . . . . . . . . 8 70 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 71 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 72 10.1. Normative References . . . . . . . . . . . . . . . . . . 10 73 10.2. Informational References . . . . . . . . . . . . . . . . 10 74 Appendix A. Setting a VPN on Multiple Interfaces . . . . . . . . 10 75 A.1. Setting VPN_0 . . . . . . . . . . . . . . . . . . . . . . 11 76 A.2. Creating an additional IKE SA . . . . . . . . . . . . . . 12 77 A.3. Creating the Child SA for VPN_1 . . . . . . . . . . . . . 12 78 A.4. Moving VPN_1 on Interface_1 . . . . . . . . . . . . . . . 13 79 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 81 1. Requirements notation 83 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 84 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 85 document are to be interpreted as described in [RFC2119]. 87 2. Introduction 89 The main scenario that motivated this document is a VPN End User 90 establishing VPN with a Security Gateway when at least one of the 91 peers has multiple interfaces. Figure 1 represents the case when the 92 VPN End User has multiple interfaces, Figure 2 represents the case 93 when the Security Gateway has multiple interfaces, and Figure 3 94 represents the case when both the VPN End User and the Security 95 Gateway have multiple interfaces. With Figure 1 and Figure 2, one of 96 the peers has n = 2 interfaces and the other has a single interface. 98 This results in creating of up to n = 2 VPNs. With Figure 3, the VPN 99 End User has n = 2 interfaces and the Security Gateway has m = 2 100 interfaces. This may lead to up to m x n VPNs. 102 +------------+ +------------+ 103 | | Interface_0 : VPN_0 | | 104 | ================= | | 105 | VPN | v | Security | 106 | End User | ================== Gateway | 107 | ================^ | | 108 | | Interface_1 : VPN_1 | | 109 +------------+ +------------+ 111 Figure 1: VPN End User with Multiple Interfaces 113 +------------+ +------------+ 114 | | Interface_0 : VPN_0 | | 115 | | ================== | 116 | VPN | v | Security | 117 | End User ================= | Gateway | 118 | | ^================= | 119 | | Interface_1 : VPN_1 | | 120 +------------+ +------------+ 122 Figure 2: Security Gateway with Multiple Interfaces 124 +------------+ +------------+ 125 | | Interface_0 Interface_0' | | 126 | ================================== | 127 | VPN | \\ // | Security | 128 | End User | // \\ | Gateway | 129 | ================================== | 130 | | Interface_1 Interface_1' | | 131 +------------+ +------------+ 133 Figure 3: VPN End User and Security Gateway with Multiple Interfaces 135 With the current IKEv2 protocol [RFC7296], each VPN requires an IKE 136 SA, and setting an IKE SA requires an authentication. Authentication 137 might require multiple round trips and an activity from the End User 138 (like EAP-SIM [RFC4186] or EAP-TLS [RFC5216]) as well as crypto 139 operations that would introduce an additional delay. 141 Another scenario is a load-balancing solution. Load-sharing clusters 142 often are built to be transparent for VPN End Users. In the case of 143 IPsec, this means that IKE and IPsec SA states are duplicated on 144 every cluster node where load balancer can redirect packets. The 145 drawback of such an approach is that anti-replay related data (in 146 particular Sequence Number) must be reliably synchronized between 147 participating nodes per every outgoing AH or ESP packet, which makes 148 building high-speed systems problematic. Another approach for 149 building load-balancing systems is to make VPN End Users aware of 150 them, which allows for having two or more Security Gateways sharing 151 the same ID, but each having its own IP address. In this case the 152 VPN End User first establishes an IKE SA with one of these gateways. 153 Then, at some point of time the gateway makes a decision to move 154 client to a different cluster node. This can be done with Redirect 155 Mechanism for IKEv2 [RFC5685]. The drawback of such an approach is 156 that it requires new IKE SA to be established from scratch, including 157 full authentication. In some cases this could be avoided by using 158 IKEv2 Session Resumption [RFC5723] with a new gateway. However this 159 requires VPN End User to know beforehand which new gateway to connect 160 to. So it is desirable to be able to clone existing IKE SA, to move 161 it to a different Security Gateway, and then to indicate VPN End User 162 to use this new SA. This would allow participating Security Gateways 163 to share the load between them. 165 This document introduces the possibility to clone the IKE SA in the 166 Internet Key Exchange Protocol Version 2 (IKEv2). The main idea is 167 that the peer with multiple interfaces sets the first IKE SA as 168 usual. Then it takes advantage of the fact that this SA is completed 169 and derives as many new parallel IKE SAs from it as the desired 170 number of VPNs. On each IKE SA a VPN is negotiated by creating one 171 or more IPsec SAs. This results in coexisting parallel VPNs. Then 172 the VPN End User moves each IPsec SA to its proper location using 173 MOBIKE (IKEv2 Mobility and Multihoming Protocol) [RFC4555]. 174 Alternatively, the VPN End User may first move the IKE SAs and then 175 create the IPsec SAs. 177 Note that it is up to host's local policy which additional VPNs to 178 create and when to do it. The process of selecting address pairs for 179 migration is a local matter. Furthermore, in the case of multiple 180 interfaces on both ends, care should be taken to avoid the VPNs being 181 duplicated by both ends or moved to the both interfaces. 183 In addition multiple MOBIKE operation may be involved from the 184 Security Gateway or the VPN End User. Suppose, as depicted in 185 Figure 3 for example that the cloned VPN is between Interface _0 and 186 Interface_0', and the VPN End User and the Security Gateway want to 187 move it to Interface_1 and Interface_1'. The VPN End User may 188 initiate a MOBIKE exchange in order to move it to Interface_1, in 189 which case the cloned VPN is now between Interface_1 and 190 Interface_0'. Then the Security Gateway may also initiate a MOBIKE 191 exchange in order to move the VPN to Interface_1' in which case the 192 VPN has reached its final destination. 194 The combination of the IKE SA cloning with MOBIKE protocol provides 195 IPsec communications with multiple interfaces the following 196 advantages. First, cloning the IKE SA requires very few 197 modifications to already existing IKEv2 implementations. Then, it 198 takes advantage of the already existing and widely deployed MOBIKE 199 protocol. Finally, it keeps a dedicated IKE SA for each VPN which 200 simplifies reachability tests and VPN maintenance. 202 Note also that the cloning of the IKE SA is independent from MOBIKE 203 and can also address other future scenarios not described in the 204 current document. 206 3. Terminology 208 This section defines terms and acronyms used in this document. 210 - VPN: Virtual Private Network - one or more Child (IPsec) SAs 211 created in tunnel mode between two peers. 213 - VPN End User: designates the end user that initiates the VPN with 214 a Security Gateway. This end user may be mobile and moves its 215 VPN from one Security Gateway to another. 217 - Security Gateway: designates a point of attachment for the VPN 218 service. In this document, the VPN service is provided by 219 multiple Security Gateways. Each Security Gateway may be 220 considered as a specific hardware. 222 - IKE SA: The IKE SA (IKE Security Association) is defined in 223 [RFC7296]. 225 4. Protocol Overview 227 This document specifies how to create a clone of existing IKE SAs 228 without performing new authentication. In order to achieve this 229 goal, the document proposes that the two peers agree upon their 230 ability to clone the IKE SA. This is done during the IKE_AUTH 231 exchange by exchanging the CLONE_IKE_SA_SUPPORTED notifications. To 232 create a new parallel IKE SA, one of the peers initiates a 233 CREATE_CHILD_SA exchange as if it would rekey the existing IKE SA. 234 In order to indicate the current IKE SA must not be deleted, the 235 initiator includes the CLONE_IKE_SA notification in the 236 CREATE_CHILD_SA exchange. This results in two parallel IKE SAs. 238 Note, that without the CLONE_IKE_SA notification the old IKE SA would 239 be deleted after the rekey is successfully completed (as specified in 240 Section 2.8 of [RFC7296]. 242 5. Protocol Details 244 5.1. Support Negotiation 246 The initiator and the responder indicate their support for cloning 247 IKE SA by exchanging the CLONE_IKE SA_SUPPORTED notifications. This 248 notification MUST be sent in the IKE_AUTH exchange (in case of 249 multiple IKE_AUTH exchanges - in the first IKE_AUTH message from 250 initiator and in the last IKE_AUTH message from responder). If both 251 initiator and responder send this notification during the IKE_AUTH 252 exchange, peers may clone this IKE SA. In the other case the IKE SA 253 MUST NOT be cloned. 255 Initiator Responder 256 ------------------------------------------------------------------- 257 HDR, SA, KEi, Ni --> 258 <-- HDR, SA, KEr, Nr 259 HDR, SK {IDi, AUTH, 260 SA, TSi, TSr, 261 N(CLONE_IKE_SA_SUPPORTED)} --> 262 <-- HDR, SK {IDr, AUTH, 263 SA, TSi, TSr, 264 N(CLONE_IKE_SA_SUPPORTED)} 266 5.2. Cloning the IKE SA 268 The initiator of the rekey exchange includes the CLONE_IKE_SA 269 notification in a CREATE_CHILD_SA request for rekeying the IKE SA. 270 The CLONE_IKE_SA notification indicates that the current IKE SA will 271 not be immediately deleted once the new IKE SA is created. Instead 272 two parallel IKE SAs are expected to coexist. The current IKE SA 273 becomes the old IKE SA and the newly negotiated IKE SA becomes the 274 new IKE SA. The CLONE_IKE_SA notification MUST appear only in 275 request message of the CREATE_CHILD_SA exchange concerning the IKE SA 276 rekey. If the CLONE_IKE_SA notification appears in any other 277 message, it MUST be ignored. 279 Initiator Responder 280 ------------------------------------------------------------------- 281 HDR, SK {N(CLONE_IKE_SA), SA, Ni, KEi} --> 283 If the CREATE_CHILD_SA request is concerned with an IKE SA rekey and 284 contains the CLONE_IKE_SA notification, the responder proceeds to the 285 IKE SA rekey, creates the new IKE SA, and keeps the old IKE SA. No 286 additional Notify Payloads are included in the CREATE_CHILD_SA 287 response as represented below: 289 <-- HDR, SK {SA, Nr, KEr} 291 When the IKE SA is cloned, peers MUST NOT transfer existing Child 292 SAs, that were created by the old IKE SA, to the newly created IKE 293 SA. So, all signalling messages, concerning those Child SAs would 294 continue to be sent over the old IKE SA. This is different from the 295 regular IKE SA rekey in IKEv2. 297 5.3. Error Handling 299 There may be conditions when responder for some reason is unable or 300 unwilling to clone the IKE SA. This inability may be temporary or 301 permanent. 303 Temporary inability occurs when the responder doesn't have enough 304 resources at the moment to clone an IKE SA or when the IKE SA is 305 being deleted by the responder. In this case the responder SHOULD 306 reject the request to clone the IKE SA with the TEMPORARY_FAILURE 307 notification. 309 <-- HDR, SK {N(TEMPORARY_FAILURE)} 311 After receiving this notification the initiator MAY retry its request 312 after waiting some period of time. See Section 2.25 of [RFC7296] for 313 details. 315 In some cases, responder may have restrictions on the number of co- 316 existing IKE SAs with one peer. These restrictions may be either 317 implicit (some devices may have enough resources to handle only a few 318 IKE SAs) or explicit (provided by some configuration parameter). If 319 the initiator wants to clone more IKE SAs, than responder is able or 320 is configured to handle, the responder SHOULD reject the request with 321 the NO_ADDITIONAL_SAS notification. 323 <-- HDR, SK {N(NO_ADDITIONAL_SAS)} 325 This condition is considered permanent and the initiator SHOULD NOT 326 retry to clone an IKE SA until some of existing SAs with the 327 responder are deleted. 329 6. Payload Description 331 Figure 4 illustrates the Notify Payload packet format as described in 332 section 3. 10 of [RFC7296]. This format is used for both the 333 CLONE_IKE_SA and the CLONE_IKE_SA_SUPPORTED notifications. 335 The CLONE_IKE_SA_SUPPORTED notification is used in an IKEv2 exchange 336 of type IKE_AUTH and the CLONE_IKE_SA is used in an IKEv2 exchange of 337 type CREATE_CHILD_SA. 339 1 2 3 340 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 1 341 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 342 | Next Payload |C| RESERVED | Payload Length | 343 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 344 | Protocol ID | SPI Size | Notify Message Type | 345 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 347 Figure 4: Notify Payload 349 The fields Next Payload, Critical Bit, RESERVED and Payload Length 350 are defined in [RFC7296]. Specific fields defined in this document 351 are: 353 - Protocol ID (1 octet): set to zero. 355 - SPI Size (1 octet): set to zero. 357 - Notify Message Type (2 octets): Specifies the type of notification 358 message. It is set to for the CLONE_IKE_SA 359 notification or to for the CLONE_IKE_SA_SUPPORTED 360 Notification. 362 7. IANA Considerations 364 IANA is requested to allocate two values in the "IKEv2 Notify Message 365 Types - Status Types registry": 367 IKEv2 Notify Message Types - Status Types 368 ----------------------------------------- 369 CLONE_IKE_SA_SUPPORTED 370 CLONE_IKE_SA 372 8. Security Considerations 374 The protocol defined in this document does not modify IKEv2. 375 Security considerations for cloning an IKE SA are mostly the same as 376 those for base IKEv2 protocol described in [RFC7296]. 378 Cloning an IKE SA provides the ability for an initiator to duplicate 379 existing SAs. As a result it may influence any accounting or control 380 mechanisms based on a single IKE SA per authentication. 382 Suppose a system has a limit on the number of IKE SAs it can handle. 383 In this case, cloning an IKE SA may provide a way for resource 384 exhaustion, as a single end user may populate multiple IKE SAs. 386 Suppose a system shares the IPsec resources by limiting the number of 387 Child SAs per IKE SA. With a single IKE SA per end user, this 388 provides an equal resource sharing. In this case, cloning the IKE SA 389 provides means for an end user to overpass this limit. Such system 390 should evaluate the number of Child SAs over the number of all IKE 391 SAs associated to an end user. 393 Note, that these issues are not unique to the ability of cloning the 394 IKE SA, as multiple IKE SAs between two peers may be created without 395 involving a cloning method. Note also, that implementation can 396 always limit the number of cloned IKE SAs. 398 Suppose VPN or any other IPsec based service monitoring is based on 399 the liveliness of the first IKE SA. Such a system considers a 400 service is accessed or used from the time IKE performs an 401 authentication to the time the IKE SA is deleted. Such accounting 402 methods were fine as any IKE SA required an authentication exchange. 403 As cloning the IKE SA skips the authentication phase, it may make it 404 possible to delete the initial IKE SA while the service is being used 405 on the cloned IKE SA. Such accounting methods should consider the 406 service is being used from the first IKE SA establishment to until 407 the last IKE SA is removed. 409 When cloning, an IKE SA is used to build load-balancing systems, then 410 there is a necessity to transfer IKE SA states between the nodes of 411 load-sharing cluster. Since IKE SA state contains sensitive 412 information, such as session keys, implementations must take all due 413 precautions. Such precautions might include using technical and/or 414 administrative means to protect IKE SA state data. The details of 415 what is transferred and how it is protected are out of scope of this 416 document. 418 9. Acknowledgments 420 The ideas of this draft came from various inputs from the ipsecme WG 421 and from discussions with Tero Kivinen and Michael Richardson. Yaron 422 Sheffer, Tero Kivinen provided significant inputs to set the current 423 design of the protocol as well as its designation. 425 10. References 426 10.1. Normative References 428 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 429 Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ 430 RFC2119, March 1997, 431 . 433 [RFC4555] Eronen, P., "IKEv2 Mobility and Multihoming Protocol 434 (MOBIKE)", RFC 4555, DOI 10.17487/RFC4555, June 2006, 435 . 437 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 438 Kivinen, "Internet Key Exchange Protocol Version 2 439 (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October 440 2014, . 442 10.2. Informational References 444 [RFC4186] Haverinen, H., Ed. and J. Salowey, Ed., "Extensible 445 Authentication Protocol Method for Global System for 446 Mobile Communications (GSM) Subscriber Identity Modules 447 (EAP-SIM)", RFC 4186, DOI 10.17487/RFC4186, January 2006, 448 . 450 [RFC5216] Simon, D., Aboba, B., and R. Hurst, "The EAP-TLS 451 Authentication Protocol", RFC 5216, DOI 10.17487/RFC5216, 452 March 2008, . 454 [RFC5685] Devarapalli, V. and K. Weniger, "Redirect Mechanism for 455 the Internet Key Exchange Protocol Version 2 (IKEv2)", RFC 456 5685, DOI 10.17487/RFC5685, November 2009, 457 . 459 [RFC5723] Sheffer, Y. and H. Tschofenig, "Internet Key Exchange 460 Protocol Version 2 (IKEv2) Session Resumption", RFC 5723, 461 DOI 10.17487/RFC5723, January 2010, 462 . 464 Appendix A. Setting a VPN on Multiple Interfaces 466 This section is informational and exposes how a VPN End User as 467 illustrated in Figure 1 can build two VPNs on its two interfaces 468 without multiple authentications. Other cases represented in 469 Figure 2 and Figure 3 are similar and can be easily derived from this 470 case. The mechanism is based on cloning the IKE SA and the MOBIKE 471 extension [RFC4555]. 473 A.1. Setting VPN_0 475 First, the VPN End User negotiates a VPN using one interface. This 476 involves regular IKEv2 exchanges. In addition, the VPN End User and 477 the Security Gateway advertise their support for MOBIKE. At the end 478 of the IKE_AUTH exchange, VPN_0 is set as represented in Figure 5. 480 +------------+ +------------+ 481 | | Interface_0 : VPN_0 | | 482 | ================= | | 483 | VPN | v | Security | 484 | End User | ================== Gateway | 485 | = | | 486 | | Interface_1 | | 487 +------------+ +------------+ 489 Figure 5: VPN End User Establishing VPN_0 491 The exchanges are completely described in [RFC7296] and [RFC4555]. 492 First, peers negotiate IKE SA parameters and exchange nonces and 493 public keys in IKE_SA_INIT exchange. In the figure below they also 494 proceed to NAT detection because of the use of MOBIKE. 496 Initiator Responder 497 ------------------------------------------------------------------- 498 (IP_I0:500 -> IP_R:500) 499 HDR, SA, KEi, Ni, 500 N(NAT_DETECTION_SOURCE_IP), 501 N(NAT_DETECTION_DESTINATION_IP) --> 503 <-- (IP_R:500 -> IP_I0:500) 504 HDR, SA, KEr, Nr, 505 N(NAT_DETECTION_SOURCE_IP), 506 N(NAT_DETECTION_DESTINATION_IP) 508 Then the initiator and the responder proceed to the IKE_AUTH 509 exchange, advertise their support for MOBIKE and their ability to 510 clone the IKE SA - with the MOBIKE_SUPPORTED and the 511 CLONE_IKE_SA_SUPPORTED notifications - and negotiate the Child SA for 512 VPN_0. Optionally, the initiator and the responder can advertise 513 their multiple interfaces using the ADDITIONAL_IP4_ADDRESS and/or 514 ADDITIONAL_IP6_ADDRESS notifications. 516 (IP_I0:4500 -> IP_R:4500) 517 HDR, SK {IDi, AUTH, 518 SA, TSi, TSr, 519 N(MOBIKE_SUPPORTED), 520 [N(ADDITIONAL_IP*_ADDRESS)+,] 521 N(CLONE_IKE_SA_SUPPORTED)} --> 523 <-- (IP_R:4500 -> IP_I0:4500) 524 HDR, SK {IDr, AUTH, 525 SA, TSi, TSr, 526 N(MOBIKE_SUPPORTED), 527 [N(ADDITIONAL_IP*_ADDRESS)+,] 528 N(CLONE_IKE_SA_SUPPORTED)} 530 A.2. Creating an additional IKE SA 532 In our case the VPN End User wants to establish an additional VPN 533 with its Interface_1. The VPN End User will first establish a 534 parallel IKE SA using a CREATE_CHILD_SA that concerns an IKE SA rekey 535 associated with a CLONE_IKE_SA notification. This results in two 536 separate IKE SAs between the VPN End User and the Security Gateway. 537 Currently both IKE SAs are set using Interface_0 of the VPN End User. 539 Initiator Responder 540 ------------------------------------------------------------------- 541 (IP_I0:4500 -> IP_R:4500) 542 HDR, SK {N(CLONE_IKE_SA), 543 SA, Ni, KEi} --> 544 <-- (IP_R:4500 -> IP_I0:4500) 545 HDR, SK {SA, Nr, KEr} 547 A.3. Creating the Child SA for VPN_1 549 Once the new IKE SA has been created, the VPN End User can initiate a 550 CREATE_CHILD_SA exchange that concerns the creation of a Child SA for 551 VPN_1. The newly created VPN_1 will use Interface_0 of the VPN End 552 User. 554 It is out of scope for the document to define how the VPN End User 555 handles traffic with multiple interfaces. The VPN End User can use 556 the same inner IP address on its multiple interfaces. In this case, 557 the same Traffic Selectors (that is the IP address used for VPN_0 and 558 VPN_1) can match for both VPNs VPN_0 and VPN_1. The VPN End User 559 must be aware of such a match and be able to manage it. It can for 560 example use distinct Traffic Selectors on both VPNs using different 561 ports, manage the order of its SPD or have SPD defined per 562 interfaces. Defining these mechanisms are out of scope of this 563 document. Alternatively, the VPN End User can use a different inner 564 IP address for each interface. 566 The creation of VPN_1 is performed via the newly created IKE SA as 567 follows: 569 Initiator Responder 570 ------------------------------------------------------------------- 571 (IP_I0:4500 -> IP_R:4500) 572 HDR(new), SK(new) {SA, TSi, TSr} --> 574 <-- (IP_R:4500 -> IP_I0:4500) 575 HDR(new), SK(new) {SA, TSi, TSr} 577 The resulting configuration is depicted in Figure 6. VPN_0 and VPN_1 578 have been created, but both are using the same Interface: 579 Interface_0. 581 +------------+ +------------+ 582 | | Interface_0 : VPN_0, VPN_1 | | 583 | ==================== | | 584 | VPN ================= v | Security | 585 | End User | v =============== Gateway | 586 | | ================== | 587 | | Interface_1 | | 588 +------------+ +------------+ 590 Figure 6: VPN End User Establishing VPN_0 and VPN_1 592 A.4. Moving VPN_1 on Interface_1 594 In this section, MOBIKE is used to move VPN_1 on interface_1. The 595 exchange is described in [RFC4555]. 597 (IP_I1:4500 -> IP_R:4500) 598 HDR(new), SK(new) {N(UPDATE_SA_ADDRESSES), 599 N(NAT_DETECTION_SOURCE_IP), 600 N(NAT_DETECTION_DESTINATION_IP), 601 N(COOKIE2)} --> 603 <-- (IP_R:4500 -> IP_I1:4500) 604 HDR(new), SK(new) { 605 N(NAT_DETECTION_SOURCE_IP), 606 N(NAT_DETECTION_DESTINATION_IP), 607 N(COOKIE2)} 609 This results in the situation as described in Figure 7. 611 +------------+ +------------+ 612 | | Interface_0 : VPN_0 | | 613 | ================== | | 614 | VPN | v | Security | 615 | End User | ================= Gateway | 616 | =================^ | | 617 | | Interface_1 : VPN_1 | | 618 +------------+ +------------+ 620 Figure 7: VPN End User with Multiple Interfaces 622 Authors' Addresses 624 Daniel Migault 625 Ericsson 626 8400 boulevard Decarie 627 Montreal, QC H4P 2N2 628 Canada 630 Email: daniel.migault@ericsson.com 632 Valery Smyslov 633 ELVIS-PLUS 634 PO Box 81 635 Moscow (Zelenograd) 124460 636 Russian Federation 638 Phone: +7 495 276 0211 639 Email: svan@elvis.ru