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Gundavelli 7 Cisco 8 October 19, 2015 10 MAG Multipath Binding Option 11 draft-seite-dmm-rg-multihoming-02.txt 13 Abstract 15 The document [RFC4908] proposes to rely on multiple Care-of Addresses 16 (CoAs) capabilities of Mobile IP [RFC6275] an Network Mobility (NEMO; 17 [RFC3963]) to enable Multihoming technology for Small-Scale Fixed 18 Networks. In the continuation of [RFC4908], this document specifies 19 a multiple proxy Care-of Addresses (pCoAs) extension for Proxy Mobile 20 IPv6 [RFC5213]. This extension allows a multihomed Mobile Access 21 Gateway (MAG) to register more than one proxy care-of-address to the 22 Local Mobility Anchor (LMA). 24 Status of This Memo 26 This Internet-Draft is submitted in full conformance with the 27 provisions of BCP 78 and BCP 79. 29 Internet-Drafts are working documents of the Internet Engineering 30 Task Force (IETF). Note that other groups may also distribute 31 working documents as Internet-Drafts. The list of current Internet- 32 Drafts is at http://datatracker.ietf.org/drafts/current/. 34 Internet-Drafts are draft documents valid for a maximum of six months 35 and may be updated, replaced, or obsoleted by other documents at any 36 time. It is inappropriate to use Internet-Drafts as reference 37 material or to cite them other than as "work in progress." 39 This Internet-Draft will expire on April 21, 2016. 41 Copyright Notice 43 Copyright (c) 2015 IETF Trust and the persons identified as the 44 document authors. All rights reserved. 46 This document is subject to BCP 78 and the IETF Trust's Legal 47 Provisions Relating to IETF Documents 48 (http://trustee.ietf.org/license-info) in effect on the date of 49 publication of this document. Please review these documents 50 carefully, as they describe your rights and restrictions with respect 51 to this document. Code Components extracted from this document must 52 include Simplified BSD License text as described in Section 4.e of 53 the Trust Legal Provisions and are provided without warranty as 54 described in the Simplified BSD License. 56 Table of Contents 58 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 59 2. Conventions and Terminology . . . . . . . . . . . . . . . . . 4 60 2.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 4 61 2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 62 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 5 63 3.1. Example Call Flow . . . . . . . . . . . . . . . . . . . . 5 64 3.2. Traffic distribution schemes . . . . . . . . . . . . . . 6 65 4. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 7 66 4.1. MAG Multipath-Binding Option . . . . . . . . . . . . . . 7 67 4.2. MAG Identifier Option . . . . . . . . . . . . . . . . . . 9 68 4.3. New Status Code for Proxy Binding Acknowledgement . . . . 10 69 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 70 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 71 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 72 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 73 8.1. Normative References . . . . . . . . . . . . . . . . . . 11 74 8.2. Informative References . . . . . . . . . . . . . . . . . 12 75 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 77 1. Introduction 79 Using several links, the multihoming technology can improve 80 connectivity availability and quality of communications; the goals 81 and benefits of multihoming are as follows: 83 o Redundancy/Fault-Recovery 85 o Load balancing 87 o Load sharing 89 o Preferences settings 91 According to [RFC4908], users of Small-Scale Networks can take 92 benefit of multihoming using mobile IP [RFC6275] and Network Mobility 93 (NEMO) [RFC3963] architecture in a mobile and fixed networking 94 environment. This document was introducing the concept of multiple 95 Care-of Addresses (CoAs) that have been specified since then 96 [RFC5648]. 98 In the continuation of [RFC4908], a Proxy Mobile IPv6 [RFC5213] based 99 multihomed achitecture could be defined. The motivation to update 100 [RFC4908] with proxy Mobile IPv6 is to leverage on latest mobility 101 working group achievments, namely: 103 o using GRE as mobile tuneling, possibly with its key extension 104 [RFC5845] (a possible reason to use GRE is given on Section 3.2). 106 o using UDP encapsulation [RFC5844] in order to support NAT 107 traversal in IPv4 networking environment. 109 o Prefix Delegation mechanism [RFC7148]. 111 Proxy Mobile IPv6 (PMIPv6) relies on two mobility entities: the 112 mobile access gateway (MAG), which acts as the default gateway for 113 the end-node and the local mobility anchor (LMA), which acts as the 114 topological anchor point. Point-to-point links are established, 115 using IP-in-IP tunnels, between MAG and LMA. Then, the MAG and LMA 116 are distributing traffic over these tunnels. All PMIPv6 operations 117 are performed on behalf of the end-node and its corespondent node, it 118 thus makes PMIPv6 well adapted to multihomed architecture, as 119 considered in [RFC4908]. Taking the LTE and DSL networking 120 environments as an example, the PMIPv6 based multihomed architecture 121 is depicted on Figure 1. Flow-1,2 and 3 are distributed either on 122 Tunnel-1 (over LTE) or Tunnel-2 (ober DSL), while Flow-4 is spread on 123 both Tunnel-1 and 2. 125 Flow-1 126 | 127 |Flow-2 _----_ 128 | | CoA-1 _( )_ Tunnel-1 129 | | .---=======( LTE )========\ Flow-1 130 | | | (_ _) \Flow-4 131 | | | '----' \ 132 | | +=====+ \ +=====+ _----_ 133 | '-| | \ | | _( )_ 134 '---| MAG | | LMA |-( Internet )-- 135 .---| | | | (_ _) 136 | .-| | / | | '----' 137 | | +=====+ / +=====+ 138 | | | _----_ / 139 | | | CoA-2 _( )_ Tunnel-2 / 140 | | .---=======( DSL )========/ Flow-2 141 | | (_ _) Flow-3 142 | | '----' Flow-4 143 |Flow-3 144 | 145 Flow0=-4 147 Figure 1: Multihomed MAG using Proxy Mobile IPv6 149 Current version of Proxy Mobile IPv6 does not allow a MAG to register 150 more than one proxy Care-of-Adresse to the LMA. In other words, only 151 one MAG/LMA link, i.e. IP-in-IP tunnel, tunnel can be used at the 152 same time. This document overcome this limitation by defining the 153 multiple proxy Care-of Addresses (pCoAs) extension for Proxy Mobile 154 IPv6. 156 2. Conventions and Terminology 158 2.1. Conventions 160 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 161 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 162 document are to be interpreted as described in RFC 2119 [RFC2119]. 164 2.2. Terminology 166 All mobility related terms used in this document are to be 167 interpreted as defined in [RFC5213], [RFC5844] and [RFC7148]. 168 Additionally, this document uses the following terms: 170 IP-in-IP 171 IP-within-IP encapsulation [RFC2473], [RFC4213] 173 3. Overview 175 3.1. Example Call Flow 177 Figure 2 is the callflow detailing hybrid access support with PMIPv6. 178 The MAG in this example scenario is equipped with both WLAN and LTE 179 interfaces and is also configured with the MAG functionality. A 180 logical-NAI with ALWAYS-ON configuration is enabled on the MAG. The 181 mobility session that is created on the LMA is for the logical-NAI. 182 The IP hosts MN_1 and MN_2 are assigned IP addresses from the 183 delegated mobile network prefix. 185 +=====+ +=====+ +=====+ +=====+ +=====+ +=====+ 186 | MN_1| | MN_2| | MAG | | WLAN| | LTE | | LMA | 187 +=====+ +=====+ +=====+ +=====+ +=====+ +=====+ 188 | | | | | | 189 | | | | | | 190 | | | (1) ATTACH | | | 191 | | | <--------> | | | 192 | | | (2) ATTACH | | 193 | | | <---------------------->| | 194 | | | (3) PBU (NAI, MAG-NAI, DMNP, MMB) | 195 | | | ------------------------*----------> | 196 | | | (4) PBA (NAI, DMNP) | 197 | | | <-----------------------*----------- | 198 | | | (5) TUNNEL INTERFACE CREATION | 199 | | |-============== TUNNEL ==*===========-| 200 | | | | 201 | | | (6) PBU (NAI, MAG-NAI, DMNP, MMB) | 202 | | | -----------*-----------------------> | 203 | | | (7) PBA (NAI, DMNP) | 204 | | | <----------*------------------------ | 205 | | | (8) TUNNEL INTERFACE CREATION | 206 | | |-===========*== TUNNEL ==============-| 207 | (9) | | 208 | <------------------> | | 209 | | (10) | | 210 | |<-----------> | | 212 Figure 2: Functional Separation of the Control and User Plane 214 3.2. Traffic distribution schemes 216 IP mobility protocols allow to establish the forwarding plane over 217 the WAN interfaces of a multihomed RG. Then, traffic distribution 218 schemes define the way to distribute data packets over these paths 219 (i.e. IP tunnels). Traffic distribution can be managed either on a 220 per-flow or on a per-packet basis: 222 o per-flow traffic management: each IP flow (both upstream and 223 downstream) is mapped to a given mobile IP tunnel, corresponding 224 to a given WAN interface. This scenario is based on IP flow 225 mobility mechanism using the Flow binding extension [RFC6089]. 226 The mobility anchor provides IP session continuity when an IP flow 227 is moved from one WAN interfaces to another. The flow binding 228 extension allows the IP mobility anchor and the RG to exchange, 229 and synchronize, IP flow management policies (i.e. policy routing 230 rules associating traffic selectors [RFC6088] to mobility 231 bindings). 233 o Per-packet management: distribute the IP packets of a same IP 234 flow, or of a group of IP flows, over more than one WAN interface. 235 In this scenario, traffic management slightly differs from the 236 default mobile IP behaviour; the mobility entities (mobility 237 anchor and client) distribute packets, belonging to a same IP 238 flow, over more than one bindings simultaneously. The definition 239 of control algorithm of a Per-packet distribution scheme (how to 240 distribute packets) is out the scope of this document. When 241 operating at the packet level, traffic distribution scheme may 242 introduce packet latency and out-of-order delivery. It may 243 require the aggeregation entities (RG and mobility anchor) to be 244 able to reorder (ans thus, to buffer) received packets before 245 delivering. A possible implementation is to use GRE as mobile 246 tunnelling mechanism, together with the GRE KEY option [RFC5845] 247 to add sequence number to GRE packets, and so, to allow the 248 receiver to perform reordering. However, more detailed buffering 249 and reordering considerations are out of the scope of this 250 document. 252 The traffic distribution scheme may require the RG and the to 253 exchange interface metrics to make traffic steering decision.For 254 example, the RG may sent its DSL synchronization rate to the mobility 255 anchor, so that the latter can make traffic forwarding decision 256 accordingly. In this case, the vendor specific mobility option 257 [RFC5094] can be used for that purpose. 259 Per-flow and per-packet distribution schemes are not exclusive 260 mechanisms; they can cohabit in the same hybrid access system. For 261 example, High throughput services (e.g. video streaming) may benefit 262 from per-packet distribution scheme, while some other may not. 263 Typically VoIP application are sensitive to latency and thus should 264 not be split over different WAN paths. In this situation, the 265 aggregation entities (RG and mobility anchor) must exchange traffic 266 management policies to associate distribution scheme, traffic and WAN 267 interface (physical or virtual). [RFC6088] and [RFC6089] define 268 traffic management on a flow basis but there is no such policy on a 269 per packet basis. 271 4. Protocol Extensions 273 4.1. MAG Multipath-Binding Option 275 The MAG Multipath-Binding option is a new mobility header option 276 defined for use with Proxy Binding Update and Proxy Binding 277 Acknowledgement messages exchanged between the local mobility anchor 278 and the mobile access gateway. 280 This mobility header option is used for requesting multipath support. 281 It indicates that the mobile access gateway is requesting the local 282 mobility anchor to register the current care-of address associated 283 with the request as one of the many care-addresses through which the 284 mobile access gateway can be reached. It is also for carrying the 285 information related to the access network associated with the care-of 286 address. 288 The MAG Multipath-Binding option has an alignment requirement of 289 8n+2. Its format is as shown in Figure 3: 291 0 1 2 3 292 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 1 293 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 294 | Type | Length | If-ATT | If-Label | 295 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 296 | Binding-Id |B|O| RESERVED | 297 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 299 Figure 3: MAG Multipath Binding Option 301 Type 303 To be assigned by IANA. 305 Length 307 8-bit unsigned integer indicating the length of the option in 308 octets, excluding the type and length fields. 310 This 8-bit field identifies the Access-Technology type of the 311 interface through which the mobile node is connected. The permitted 312 values for this are from the Access Technology Type registry defined 313 in [RFC5213]. 315 This 8-bit field represents the interface label represented as an 316 unsigned integer. The mobile node identifies the label for each of 317 the interfaces through which it registers a CoA with the home agent. 318 When using static traffic flow policies on the mobile node and the 319 home agent, the label can be used for generating forwarding policies. 320 For example, the operator may have policy which binds traffic for 321 Application "X" needs to interface with Label "Y". When a 322 registration through an interface matching Label "Y" gets activated, 323 the home agent and the mobile node can dynamically generate a 324 forwarding policy for forwarding traffic for Application "X" through 325 mobile IP tunnel matching Label "Y". Both the home agent and the 326 mobile node can route the Application-X traffic through that 327 interface. The permitted values for If-Label are 1 through 255. 329 This 8-bit field is used for carrying the binding identifier. It 330 uniquely identifies a specific binding of the mobile node, to which 331 this request can be associated. Each binding identifier is 332 represented as an unsigned integer. The permitted values are 1 333 through 254. The BID value of 0 and 255 are reserved. The mobile 334 access gateway assigns a unique value for each of its interfaces and 335 includes them in the message. 337 This flag, if set to a value of (1), is to notify the local mobility 338 anchor to consider this request as a request to update the binding 339 lifetime of all the mobile node's bindings, upon accepting this 340 specific request. This flag MUST NOT be set to a value of (1), if 341 the value of the Registration Overwrite Flag (O) flag is set to a 342 value of (1). 344 This flag, if set to a value of (1), notifies the local mobility 345 anchor that upon accepting this request, it should replace all of the 346 mobile node's existing bindings with this binding. This flag MUST 347 NOT be set to a value of (1), if the value of the Bulk Re- 348 registration Flag (B) is set to a value of (1). This flag MUST be 349 set to a value of (0), in de-registration requests. 351 Reserved 353 This field is unused in this specification. The value MUST be set 354 to zero (0) by the sender and MUST be ignored by the receiver. 356 4.2. MAG Identifier Option 358 The MAG Identifier option is a new mobility header option defined for 359 use with Proxy Binding Update and Proxy Binding Acknowledgement 360 messages exchanged between the local mobility anchor and the mobile 361 access gateway. This mobility header option is used for conveying 362 the MAG's identity. 364 This option does not have any alignment requirements. 366 0 1 2 3 367 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 1 368 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 369 | Type | Length | Subtype | Reserved | 370 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 371 | Identifier ... ~ 372 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 374 Figure 4: MAG Identifier Option 376 Type 378 To be assigned by IANA. 380 Length 382 8-bit unsigned integer indicating the length of the option in 383 octets, excluding the type and length fields. 385 Subtype 387 One byte unsigned integer used for identifying the type of the 388 Identifier field. Accepted values for this field are the 389 registered type values from the Mobile Node Identifier Option 390 Subtypes registry. 392 Reserved 394 This field is unused in this specification. The value MUST be set 395 to zero (0) by the sender and MUST be ignored by the receiver. 397 Identifier 399 A variable length identifier of type indicated in the Subtype 400 field. 402 4.3. New Status Code for Proxy Binding Acknowledgement 404 This document defines the following new Status Code value for use in 405 Proxy Binding Acknowledgement message. 407 CANNOT_SUPPORT_MULTIPATH_BINDING (Cannot Support Multipath Binding): 408 410 5. IANA Considerations 412 This document requires the following IANA actions. 414 o Action-1: This specification defines a new mobility option, the 415 MAG Multipath-Binding option. The format of this option is 416 described in Section 4.1. The type value for this 417 mobility option needs to be allocated from the Mobility Options 418 registry at . 419 RFC Editor: Please replace in Section 4.1 with the 420 assigned value and update this section accordingly. 422 o Action-2: This specification defines a new mobility option, the 423 MAG Identifier option. The format of this option is described in 424 Section 4.2. The type value for this mobility option 425 needs to be allocated from the Mobility Options registry at 426 . RFC 427 Editor: Please replace in Section 4.2 with the assigned 428 value and update this section accordingly. 430 o Action-4: This document defines a new status value, 431 CANNOT_SUPPORT_MULTIPATH_BINDING () for use in Proxy 432 Binding Acknowledgement message, as described in Section 4.3. 433 This value is to be assigned from the "Status Codes" registry at 434 . The 435 allocated value has to be greater than 127. RFC Editor: Please 436 replace in Section 4.3 with the assigned value and update 437 this section accordingly. 439 6. Security Considerations 441 This specification allows a mobile access gateway to establish 442 multiple Proxy Mobile IPv6 tunnels with a local mobility anchor, by 443 registering a care-of address for each of its connected access 444 networks. This essentially allows the mobile node's IP traffic to be 445 routed through any of the tunnel paths and either based on a static 446 or a dynamically negotiated flow policy. This new capability has no 447 impact on the protocol security. Furthermore, this specification 448 defines two new mobility header options, MAG Multipath-Binding option 449 and the MAG Identifier option. These options are carried like any 450 other mobility header option as specified in [RFC5213]. Therefore, 451 it inherits security guidelines from [RFC5213]. Thus, this 452 specification does not weaken the security of Proxy Mobile IPv6 453 Protocol, and does not introduce any new security vulnerabilities. 455 7. Acknowledgements 457 The authors of this draft would like to acknowledge the discussions 458 and feedback on this topic from the members of the DMM working group. 460 8. References 462 8.1. Normative References 464 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 465 Requirement Levels", BCP 14, RFC 2119, 466 DOI 10.17487/RFC2119, March 1997, 467 . 469 [RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P. 470 Thubert, "Network Mobility (NEMO) Basic Support Protocol", 471 RFC 3963, DOI 10.17487/RFC3963, January 2005, 472 . 474 [RFC5094] Devarapalli, V., Patel, A., and K. Leung, "Mobile IPv6 475 Vendor Specific Option", RFC 5094, DOI 10.17487/RFC5094, 476 December 2007, . 478 [RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V., 479 Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", 480 RFC 5213, DOI 10.17487/RFC5213, August 2008, 481 . 483 [RFC5648] Wakikawa, R., Ed., Devarapalli, V., Tsirtsis, G., Ernst, 484 T., and K. Nagami, "Multiple Care-of Addresses 485 Registration", RFC 5648, DOI 10.17487/RFC5648, October 486 2009, . 488 [RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy 489 Mobile IPv6", RFC 5844, DOI 10.17487/RFC5844, May 2010, 490 . 492 [RFC5845] Muhanna, A., Khalil, M., Gundavelli, S., and K. Leung, 493 "Generic Routing Encapsulation (GRE) Key Option for Proxy 494 Mobile IPv6", RFC 5845, DOI 10.17487/RFC5845, June 2010, 495 . 497 [RFC6088] Tsirtsis, G., Giarreta, G., Soliman, H., and N. Montavont, 498 "Traffic Selectors for Flow Bindings", RFC 6088, 499 DOI 10.17487/RFC6088, January 2011, 500 . 502 [RFC6089] Tsirtsis, G., Soliman, H., Montavont, N., Giaretta, G., 503 and K. Kuladinithi, "Flow Bindings in Mobile IPv6 and 504 Network Mobility (NEMO) Basic Support", RFC 6089, 505 DOI 10.17487/RFC6089, January 2011, 506 . 508 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 509 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 510 2011, . 512 [RFC7148] Zhou, X., Korhonen, J., Williams, C., Gundavelli, S., and 513 CJ. Bernardos, "Prefix Delegation Support for Proxy Mobile 514 IPv6", RFC 7148, DOI 10.17487/RFC7148, March 2014, 515 . 517 8.2. Informative References 519 [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in 520 IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473, 521 December 1998, . 523 [RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms 524 for IPv6 Hosts and Routers", RFC 4213, 525 DOI 10.17487/RFC4213, October 2005, 526 . 528 [RFC4908] Nagami, K., Uda, S., Ogashiwa, N., Esaki, H., Wakikawa, 529 R., and H. Ohnishi, "Multi-homing for small scale fixed 530 network Using Mobile IP and NEMO", RFC 4908, 531 DOI 10.17487/RFC4908, June 2007, 532 . 534 Authors' Addresses 536 Pierrick Seite 537 Orange 538 4, rue du Clos Courtel, BP 91226 539 Cesson-Sevigne 35512 540 France 542 Email: pierrick.seite@orange.com 543 Alper Yegin 544 Samsung 545 Istanbul 546 Turkey 548 Email: alper.yegin@partner.samsung.com 550 Sri Gundavelli 551 Cisco 552 170 West Tasman Drive 553 San Jose, CA 95134 554 USA 556 Email: sgundave@cisco.com