idnits 2.17.1 draft-ietf-v6ops-mobile-device-profile-18.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. 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 and authors Copyright Line does not match the current year -- The document date (February 18, 2015) is 3354 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- ** Obsolete normative reference: RFC 2460 (Obsoleted by RFC 8200) ** Obsolete normative reference: RFC 3633 (Obsoleted by RFC 8415) -- Obsolete informational reference (is this intentional?): RFC 6145 (Obsoleted by RFC 7915) -- Obsolete informational reference (is this intentional?): RFC 6434 (Obsoleted by RFC 8504) Summary: 2 errors (**), 0 flaws (~~), 1 warning (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 V6OPS Working Group D. Binet 3 Internet-Draft M. Boucadair 4 Intended status: Informational France Telecom 5 Expires: August 22, 2015 A. Vizdal 6 Deutsche Telekom AG 7 G. Chen 8 China Mobile 9 N. Heatley 10 EE 11 R. Chandler 12 eircom | meteor 13 D. Michaud 14 Rogers Communications 15 D. Lopez 16 Telefonica I+D 17 February 18, 2015 19 An Internet Protocol Version 6 (IPv6) Profile for 3GPP Mobile Devices 20 draft-ietf-v6ops-mobile-device-profile-18 22 Abstract 24 This document defines a profile that is a superset of that of the 25 connection to IPv6 cellular networks defined in the IPv6 for Third 26 Generation Partnership Project (3GPP) Cellular Hosts document. This 27 document defines an IPv6 profile that a number of operators recommend 28 in order to connect 3GPP mobile devices to an IPv6-only or dual-stack 29 wireless network (including 3GPP cellular network) with a special 30 focus on IPv4 service continuity features. 32 Both hosts and devices with capability to share their WAN (Wide Area 33 Network) connectivity are in scope. 35 Status of This Memo 37 This Internet-Draft is submitted in full conformance with the 38 provisions of BCP 78 and BCP 79. 40 Internet-Drafts are working documents of the Internet Engineering 41 Task Force (IETF). Note that other groups may also distribute 42 working documents as Internet-Drafts. The list of current Internet- 43 Drafts is at http://datatracker.ietf.org/drafts/current/. 45 Internet-Drafts are draft documents valid for a maximum of six months 46 and may be updated, replaced, or obsoleted by other documents at any 47 time. It is inappropriate to use Internet-Drafts as reference 48 material or to cite them other than as "work in progress." 49 This Internet-Draft will expire on August 22, 2015. 51 Copyright Notice 53 Copyright (c) 2015 IETF Trust and the persons identified as the 54 document authors. All rights reserved. 56 This document is subject to BCP 78 and the IETF Trust's Legal 57 Provisions Relating to IETF Documents 58 (http://trustee.ietf.org/license-info) in effect on the date of 59 publication of this document. Please review these documents 60 carefully, as they describe your rights and restrictions with respect 61 to this document. Code Components extracted from this document must 62 include Simplified BSD License text as described in Section 4.e of 63 the Trust Legal Provisions and are provided without warranty as 64 described in the Simplified BSD License. 66 Table of Contents 68 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 69 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 70 1.2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 4 71 2. Connectivity Recommendations . . . . . . . . . . . . . . . . 6 72 3. Recommendations for Cellular Devices with LAN Capabilities . 9 73 4. Advanced Recommendations . . . . . . . . . . . . . . . . . . 11 74 5. Security Considerations . . . . . . . . . . . . . . . . . . . 13 75 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 76 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 77 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 78 8.1. Normative References . . . . . . . . . . . . . . . . . . 14 79 8.2. Informative References . . . . . . . . . . . . . . . . . 16 81 1. Introduction 83 IPv6 deployment in 3GPP mobile networks is the only perennial 84 solution to the exhaustion of IPv4 addresses in those networks. 85 Several mobile operators have already deployed IPv6 [RFC2460] or are 86 in the pre-deployment phase. One of the major hurdles as perceived 87 by some mobile operators is the availability of non-broken IPv6 88 implementation in mobile devices (e.g., Section 3.3 of [OECD]). 90 [RFC7066] lists a set of features to be supported by cellular hosts 91 to connect to 3GPP mobile networks. In the light of recent IPv6 92 production deployments, additional features to facilitate IPv6-only 93 deployments while accessing IPv4-only services are to be considered. 94 This document fills this void. Concretely, this document lists means 95 to ensure IPv4 service continuity over an IPv6-only connectivity 96 given the adoption rate of this model by mobile operators. Those 97 operators require that no service degradation is experienced by 98 customers serviced with an IPv6-only model compared to the level of 99 service of customers with legacy IPv4-only devices. 101 This document defines an IPv6 profile for mobile devices listing 102 specifications produced by various Standards Developing Organizations 103 (including 3GPP, IETF, and GSMA). The objectives of this effort are: 105 1. List in one single document a comprehensive list of IPv6 features 106 for a mobile device, including both IPv6-only and dual-stack 107 mobile deployment contexts. These features cover various network 108 types such as GPRS (General Packet Radio Service) or EPC (Evolved 109 Packet Core). 111 2. Help Operators with the detailed device requirement list 112 preparation (to be exchanged with device suppliers). This is 113 also a contribution to harmonize Operators' requirements towards 114 device vendors. 116 3. Vendors to be aware of a set of features to allow for IPv6 117 connectivity and IPv4 service continuity (over an IPv6-only 118 transport). 120 The recommendations do not include 3GPP release details. For more 121 information on the 3GPP releases detail, the reader may refer to 122 Section 6.2 of [RFC6459]. 124 Some of the features listed in this profile document require to 125 activate dedicated functions at the network side. It is out of scope 126 of this document to list these network-side functions. 128 A detailed overview of IPv6 support in 3GPP architectures is provided 129 in [RFC6459]. 131 This document is organized as follows: 133 o Section 2 lists generic recommendations including functionalities 134 to provide IPv4 service continuity over an IPv6-only connectivity. 136 o Section 3 enumerates a set of recommendations for cellular devices 137 with LAN capabilities (e.g., CPE, dongles with tethering 138 features). 140 o Section 4 identifies a set of advanced recommendations to fulfill 141 requirements of critical services such as VoLTE (Voice over LTE). 143 1.1. Terminology 145 This document makes use of the terms defined in [RFC6459]. In 146 addition, the following terms are used: 148 o "3GPP cellular host" (or cellular host for short) denotes a 3GPP 149 device which can be connected to 3GPP mobile networks or IEEE 150 802.11 networks. 152 o "3GPP cellular device" (or cellular device for short) refers to a 153 cellular host which supports the capability to share its WAN (Wide 154 Area Network) connectivity. 156 o "IPv4 service continuity" denotes the features used to provide 157 access to IPv4-only services to customers serviced with an 158 IPv6-only connectivity. A typical example of IPv4 service 159 continuity technique is NAT64 [RFC6146]. 161 PREFIX64 denotes an IPv6 prefix used to build IPv4-converted IPv6 162 addresses [RFC6052]. 164 1.2. Scope 166 A 3GPP mobile network can be used to connect various user equipments 167 such as a mobile telephone, a CPE (Customer Premises Equipment) or a 168 machine-to-machine (M2M) device. Because of this diversity of 169 terminals, it is necessary to define a set of IPv6 functionalities 170 valid for any node directly connecting to a 3GPP mobile network. 171 This document describes these functionalities. 173 This document is structured to provide the generic IPv6 174 recommendations which are valid for all nodes, whatever their 175 function (e.g., host or CPE) or service (e.g., Session Initiation 176 Protocol (SIP, [RFC3261])) capability. The document also contains 177 sections covering specific functionalities for devices providing some 178 LAN functions (e.g., mobile CPE or broadband dongles). 180 The recommendations listed below are valid for both 3GPP GPRS and 181 3GPP EPS (Evolved Packet System) access. For EPS, PDN-Connection 182 term is used instead of PDP-Context. Other non-3GPP accesses 183 [TS.23402] are out of scope of this document. 185 This profile is a superset of that of the IPv6 profile for 3GPP 186 Cellular Hosts [RFC7066], which is in turn a superset of IPv6 Node 187 Requirements [RFC6434]. It targets cellular nodes, including GPRS, 188 EPC (Evolved Packet Core) and IEEE 802.11 networks, that require 189 features to ensure IPv4 service delivery over an IPv6-only transport 190 in addition to the base IPv6 service. Moreover, this profile covers 191 cellular CPEs that are used in various deployments to offer fixed- 192 like services. Recommendations inspired from real deployment 193 experiences (e.g., roaming) are included in this profile. Also, this 194 profile sketches recommendations for the sake of deterministic 195 behaviors of cellular devices when the same configuration information 196 is received over several channels. 198 For conflicting recommendations in [RFC7066] and [RFC6434] (e.g., 199 Neighbor Discovery Protocol), this profile adheres to [RFC7066]. 200 Indeed, the support of Neighbor Discovery Protocol is mandatory in 201 3GPP cellular environment as it is the only way to convey IPv6 prefix 202 towards the 3GPP cellular device. In particular, MTU (Maximum 203 Transmission Unit) communication via Router Advertisement must be 204 supported since many 3GPP networks do not have a standard MTU 205 setting. 207 This profile uses a stronger language for the support of Prefix 208 Delegation compared to [RFC7066]. The main motivation is that 209 cellular networks are more and more perceived as an alternative to 210 fixed networks for home IP-based services delivery; especially with 211 the advent of smartphones and 3GPP data dongles. There is a need for 212 an efficient mechanism to assign shorter prefix than /64 to cellular 213 hosts so that each LAN segment can get its own /64 prefix and multi- 214 link subnet issues to be avoided. The support of this functionality 215 in both cellular and fixed networks is key for fixed-mobile 216 convergence. 218 The use of address family dependent APIs (Application Programming 219 Interfaces) or hard-coded IPv4 address literals may lead to broken 220 applications when IPv6 connectivity is in use. As such, means to 221 minimize broken applications when the cellular host is attached to an 222 IPv6-only network should be encouraged. Particularly, (1) name 223 resolution libraries (e.g., [RFC3596]) must support both IPv4 and 224 IPv6; (2) applications must be independent of the underlying IP 225 address family; (3) and applications relying upon Uniform Resource 226 Identifiers (URIs) must follow [RFC3986] and its updates. Note, some 227 IETF specifications (e.g., SIP [RFC3261]) contains broken IPv6 ABNF 228 and rules to compare URIs with embedded IPv6 addresses; fixes (e.g., 229 [RFC5954]) must be used instead. 231 The recommendations included in each section are listed in a priority 232 order. 234 This document is not a standard, and conformance with it is not 235 required in order to claim conformance with IETF standards for IPv6. 236 Compliance with this profile does not require the support of all 237 enclosed items. Obviously, the support of the full set of features 238 may not be required in some deployment contexts. However, the 239 authors believe that not supporting relevant features included in 240 this profile (e.g., Customer Side Translator (CLAT, [RFC6877])) may 241 lead to a degraded level of service. 243 2. Connectivity Recommendations 245 This section identifies the main connectivity recommendations to be 246 followed by a cellular host to attach to a network using IPv6 in 247 addition to what is defined in [RFC6434] and [RFC7066]. Both dual- 248 stack and IPv6-only deployment models are considered. IPv4 service 249 continuity features are listed in this section because these are 250 critical for Operators with an IPv6-only deployment model. 252 C_REC#1: In order to allow each operator to select their own 253 strategy regarding IPv6 introduction, the cellular host 254 must support both IPv6 and IPv4v6 PDP-Contexts [TS.23060]. 255 IPv4, IPv6 or IPv4v6 PDP-Context request acceptance depends 256 on the cellular network configuration. 258 C_REC#2: The cellular host must comply with the behavior defined in 259 [TS.23060] [TS.23401] [TS.24008] for requesting a PDP- 260 Context type. In particular, the cellular host must 261 request by default an IPv6 PDP-Context if the cellular host 262 is IPv6-only and request an IPv4v6 PDP-Context if the 263 cellular host is dual-stack or when the cellular host is 264 not aware of connectivity types requested by devices 265 connected to it (e.g., cellular host with LAN capabilities 266 as discussed in Section 3): 268 * If the requested IPv4v6 PDP-Context is not supported by 269 the network, but IPv4 and IPv6 PDP types are allowed, 270 then the cellular host will be configured with an IPv4 271 address or an IPv6 prefix by the network. It must 272 initiate another PDP-Context activation in addition to 273 the one already activated for a given APN (Access Point 274 Name). 276 * If the subscription data or network configuration allows 277 only one IP address family (IPv4 or IPv6), the cellular 278 host must not request a second PDP-Context to the same 279 APN for the other IP address family. 281 The text above focuses on the specification part which 282 explains the behavior for requesting IPv6-related PDP- 283 Context(s). Understanding this behavior is important to 284 avoid having broken IPv6 implementations in cellular 285 devices. 287 C_REC#3: The cellular host must support the PCO (Protocol 288 Configuration Options) [TS.24008] to retrieve the IPv6 289 address(es) of the Recursive DNS server(s). 291 In-band signaling is a convenient method to inform the 292 cellular host about various services, including DNS 293 server information. It does not require any specific 294 protocol to be supported and it is already deployed in 295 IPv4 cellular networks to convey such DNS information. 297 C_REC#4: The cellular host must support IPv6 aware Traffic Flow 298 Templates (TFT) [TS.24008]. 300 Traffic Flow Templates are employing a packet filter to 301 couple an IP traffic with a PDP-Context. Thus a 302 dedicated PDP-Context and radio resources can be 303 provided by the cellular network for certain IP traffic. 305 C_REC#5: If the cellular host receives the DNS information in 306 several channels for the same interface, the following 307 preference order must be followed: 309 1. PCO 311 2. RA 313 3. DHCPv6 315 The purpose of this recommendation is to guarantee for a 316 deterministic behavior to be followed by all cellular hosts 317 when the DNS information is received in various channels. 319 C_REC#6: The cellular host must be able to be configured to limit 320 PDP type(s) for a given APN. The default mode is to allow 321 all supported PDP types. Note, C_REC#2 discusses the 322 default behavior for requesting PDP-Context type(s). 324 This feature is useful to drive the behavior of the UE 325 to be aligned with: (1) service-specific constraints 326 such as the use of IPv6-only for VoLTE (Voice over LTE), 327 (2) network conditions with regards to the support of 328 specific PDP types (e.g., IPv4v6 PDP-Context is not 329 supported), (3) IPv4 sunset objectives, (4) subscription 330 data, etc. 332 Note, a cellular host changing its connection between an 333 IPv6-specific APN and an IPv4-specific APN restarts the 334 ongoing applications. This may be considered as a 335 brokenness situation. 337 C_REC#7: Because of potential operational deficiencies to be 338 experienced in some roaming situations, the cellular host 339 must be able to be configured with a home PDP-Context 340 type(s) and a roaming PDP-Context type(s). The purpose of 341 the of the roaming profile is to limit the PDP type(s) 342 requested by the cellular host when out of the home 343 network. Note that distinct PDP type(s) and APN(s) can be 344 configured for home and roaming cases. 346 A detailed analysis of roaming failure cases is included 347 in [RFC7445]. 349 C_REC#8: In order to ensure IPv4 service continuity in an IPv6-only 350 deployment context, the cellular host should support a 351 method to locally construct IPv4-embedded IPv6 addresses 352 [RFC6052]. A method to learn PREFIX64 should be supported 353 by the cellular host. 355 This solves the issue when applications use IPv4 356 referrals on IPv6-only access networks. 358 In PCP-based environments, cellular hosts should follow 359 [RFC7225] to learn the IPv6 Prefix used by an upstream 360 PCP-controlled NAT64 device. If PCP is not enabled, the 361 cellular host should implement the method specified in 362 [RFC7050] to retrieve the PREFIX64. 364 C_REC#9: In order to ensure IPv4 service continuity in an IPv6-only 365 deployment context, the cellular host should implement the 366 Customer Side Translator (CLAT, [RFC6877]) function in 367 compliance with [RFC6052][RFC6145][RFC6146]. 369 CLAT function in the cellular host allows for IPv4-only 370 application and IPv4-referals to work on an IPv6-only 371 connectivity. The more applications are address family 372 independent, the less CLAT function is solicited. CLAT 373 function requires a NAT64 capability [RFC6146] in the 374 network. 376 The cellular host should only invoke the CLAT in the 377 absence of the IPv4 connectivity on the cellular side, 378 i.e., when the network does not assign an IPv4 address 379 on the cellular interface. Note, NAT64 assumes an 380 IPv6-only mode [RFC6146]. 382 The IPv4 Service Continuity Prefix used by CLAT is 383 defined in [RFC7335]. 385 CLAT and/or NAT64 do not interfere with native IPv6 386 communications. 388 3. Recommendations for Cellular Devices with LAN Capabilities 390 This section focuses on cellular devices (e.g., CPE, smartphones, or 391 dongles with tethering features) which provide IP connectivity to 392 other devices connected to them. In such case, all connected devices 393 are sharing the same 2G, 3G or LTE connection. In addition to the 394 generic recommendations listed in Section 2, these cellular devices 395 have to meet the recommendations listed below. 397 L_REC#1: The cellular device must support Prefix Delegation 398 capabilities [RFC3633] and must support Prefix Exclude 399 Option for DHCPv6-based Prefix Delegation as defined in 400 [RFC6603]. Particularly, it must behave as a Requesting 401 Router. 403 Cellular networks are more and more perceived as an 404 alternative to fixed networks for home IP-based services 405 delivery; especially with the advent of smartphones and 406 3GPP data dongles. There is a need for an efficient 407 mechanism to assign shorter prefix than /64 to cellular 408 hosts so that each LAN segment can get its own /64 409 prefix and multi-link subnet issues to be avoided. 411 In case a prefix is delegated to a cellular host using 412 DHCPv6, the cellular device will be configured with two 413 prefixes: 415 (1) one for 3GPP link allocated using SLAAC mechanism 416 and 418 (2) another one delegated for LANs acquired during 419 Prefix Delegation operation. 421 Note that the 3GPP network architecture requires both 422 the WAN (Wide Area Network) and the delegated prefix to 423 be aggregatable, so the subscriber can be identified 424 using a single prefix. 426 Without the Prefix Exclude Option, the delegating router 427 (GGSN/PGW) will have to ensure [RFC3633] compliancy 428 (e.g., halving the delegated prefix and assigning the 429 WAN prefix out of the 1st half and the prefix to be 430 delegated to the terminal from the 2nd half). 432 Because Prefix Delegation capabilities may not be 433 available in some attached networks, L_REC#3 is strongly 434 recommended to accommodate early deployments. 436 L_REC#2: The cellular CPE must be compliant with the requirements 437 specified in [RFC7084]. 439 There are several deployments, particularly in emerging 440 countries, that relies on mobile networks to provide 441 broadband services (e.g., customers are provided with 442 mobile CPEs). 444 Note, this profile does not require IPv4 service 445 continuity techniques listed in [RFC7084] because those 446 are specific to fixed networks. IPv4 service continuity 447 techniques specific to the mobile networks are included 448 in this profile. 450 This recommendation does not apply to handsets with 451 tethering capabilities; it is specific to cellular CPEs 452 in order to ensure the same IPv6 functional parity for 453 both fixed and cellular CPEs. Note, modern CPEs are 454 designed with advanced functions such as link 455 aggregation that consists in optimizing the network 456 usage by aggregating the connectivity resources offered 457 via various interfaces (e.g., DSL, LTE, WLAN, etc.) or 458 offloading the traffic via a subset of interfaces. 459 Mutualizing IPv6 features among these interface types is 460 important for the sake of specification efficiency, 461 service design simplification and validation effort 462 optimization. 464 L_REC#3: For deployments requiring to share the same /64 prefix, the 465 cellular device should support [RFC7278] to enable sharing 466 a /64 prefix between the 3GPP interface towards the GGSN/ 467 PGW (WAN interface) and the LAN interfaces. 469 Prefix Delegation (refer to L_REC#1) is the target 470 solution for distributing prefixes in the LAN side but, 471 because the device may attach to earlier 3GPP release 472 networks, a mean to share a /64 prefix is also 473 recommended [RFC7278]. 475 [RFC7278] must be invoked only if Prefix Delegation is 476 not in use. 478 L_REC#4: In order to allow IPv4 service continuity in an IPv6-only 479 deployment context, the cellular device should support the 480 Customer Side Translator (CLAT) [RFC6877]. 482 Various IP devices are likely to be connected to 483 cellular device, acting as a CPE. Some of these devices 484 can be dual-stack, others are IPv6-only or IPv4-only. 485 IPv6-only connectivity for cellular device does not 486 allow IPv4-only sessions to be established for hosts 487 connected on the LAN segment of cellular devices. 489 In order to allow IPv4 sessions establishment initiated 490 from devices located on LAN segment side and target IPv4 491 nodes, a solution consists in integrating the CLAT 492 function in the cellular device. As elaborated in 493 Section 2, the CLAT function allows also IPv4 494 applications to continue running over an IPv6-only 495 device. 497 The cellular host should only invoke the CLAT in the 498 absence of the IPv4 connectivity on the cellular side, 499 i.e., when the network does not assign an IPv4 address 500 on the cellular interface. 502 The IPv4 Service Continuity Prefix used by CLAT is 503 defined in [RFC7335]. 505 L_REC#5: If a RA MTU is advertised from the 3GPP network, the 506 cellular device should relay that upstream MTU information 507 to the downstream attached LAN devices in RA. 509 Receiving and relaying RA MTU values facilitates a more 510 harmonious functioning of the mobile core network where 511 end nodes transmit packets that do not exceed the MTU 512 size of the mobile network's GTP tunnels. 514 [TS.23060] indicates providing a link MTU value of 1358 515 octets to the 3GPP cellular device will prevent the IP 516 layer fragmentation within the transport network between 517 the cellular device and the GGSN/PGW. 519 4. Advanced Recommendations 521 This section identifies a set of advanced recommendations to fulfill 522 requirements of critical services such as VoLTE. 524 A_REC#1: The cellular host must support ROHC RTP Profile (0x0001) 525 and ROHC UDP Profile (0x0002) for IPv6 ([RFC5795]). Other 526 ROHC profiles may be supported. 528 Bandwidth in cellular networks must be optimized as much 529 as possible. ROHC provides a solution to reduce 530 bandwidth consumption and to reduce the impact of having 531 bigger packet headers in IPv6 compared to IPv4. 533 "RTP/UDP/IP" ROHC profile (0x0001) to compress RTP 534 packets and "UDP/IP" ROHC profile (0x0002) to compress 535 RTCP packets are required for Voice over LTE (VoLTE) by 536 IR.92.4.0 section 4.1 [IR92]. Note, [IR92] indicates 537 that the host must be able to apply the compression to 538 packets that are carried over the voice media dedicated 539 radio bearer. 541 A_REC#2: The cellular host should support PCP [RFC6887]. 543 The support of PCP is seen as a driver to save battery 544 consumption exacerbated by keepalive messages. PCP also 545 gives the possibility of enabling incoming connections 546 to the cellular device. Indeed, because several 547 stateful devices may be deployed in wireless networks 548 (e.g., NAT64 and/or IPv6 Firewalls), PCP can be used by 549 the cellular host to control network-based NAT64 and 550 IPv6 Firewall functions which will reduce per- 551 application signaling and save battery consumption. 553 According to [Power], the consumption of a cellular 554 device with a keep-alive interval equal to 20 seconds 555 (that is the default value in [RFC3948] for example) is 556 29 mA (2G)/34 mA (3G). This consumption is reduced to 557 16 mA (2G)/24 mA (3G) when the interval is increased to 558 40 seconds, to 9.1 mA (2G)/16 mA (3G) if the interval is 559 equal to 150 seconds, and to 7.3 mA (2G)/14 mA (3G) if 560 the interval is equal to 180 seconds. When no keep- 561 alive is issued, the consumption would be 5.2 mA 562 (2G)/6.1 mA (3G). The impact of keepalive messages 563 would be more severe if multiple applications are 564 issuing those messages (e.g., SIP, IPsec, etc.). 566 PCP allows to avoid embedding ALGs (Application Level 567 Gateways) at the network side (e.g., NAT64) to manage 568 protocols which convey IP addresses and/or port numbers 569 (see Section 2.2 of [RFC6889]). Avoiding soliciting 570 ALGs allows for more easiness to make evolve a service 571 independently of the underlying transport network. 573 A_REC#3: In order for host-based validation of DNS Security 574 Extensions (DNSSEC) to continue to function in an IPv6-only 575 connectivity with NAT64 deployment context, the cellular 576 host should embed a DNS64 function ([RFC6147]). 578 This is called "DNS64 in stub-resolver mode" in 579 [RFC6147]. 581 As discussed in Section 5.5 of [RFC6147], a security- 582 aware and validating host has to perform the DNS64 583 function locally. 585 Because synthetic AAAA records cannot be successfully 586 validated in a host, learning the PREFIX64 used to 587 construct IPv4-converted IPv6 addresses allows the use 588 of DNSSEC [RFC4033] [RFC4034], [RFC4035]. Means to 589 configure or discover a PREFIX64 are required on the 590 cellular device as discussed in C_REC#8. 592 [RFC7051] discusses why a security-aware and validating 593 host has to perform the DNS64 function locally and why 594 it has to be able to learn the proper PREFIX64(s). 596 A_REC#4: When the cellular host is dual-stack connected (i.e., 597 configured with an IPv4 address and IPv6 prefix), it should 598 support means to prefer native IPv6 connection over 599 connection established through translation devices (e.g., 600 NAT44 and NAT64). 602 When both IPv4 and IPv6 DNS servers are configured, a 603 dual-stack host must contact first its IPv6 DNS server. 604 This preference allows to offload IPv4-only DNS servers. 606 Cellular hosts should follow the procedure specified in 607 [RFC6724] for source address selection. 609 5. Security Considerations 611 The security considerations identified in [RFC7066] and [RFC6459] are 612 to be taken into account. 614 In the case of cellular CPEs, compliance with L_REC#2 entails 615 compliance with [RFC7084], which in turn recommends compliance with 616 Recommended Simple Security Capabilities in Customer Premises 617 Equipment (CPE) for Providing Residential IPv6 Internet Service 618 [RFC6092]. Therefore, the security considerations in Section 6 of 619 [RFC6092] are relevant. In particular, it bears repeating here that 620 the true impact of stateful filtering may be a reduction in security, 621 and that IETF make no statement, expressed or implied, as to whether 622 using the capabilities described in any of these documents ultimately 623 improves security for any individual users or for the Internet 624 community as a whole. 626 The cellular host must be able to generate IPv6 addresses which 627 preserve privacy. The activation of privacy extension (e.g., using 628 [RFC7217]) makes it more difficult to track a host over time when 629 compared to using a permanent Interface Identifier. Tracking a host 630 is still possible based on the first 64 bits of the IPv6 address. 631 Means to prevent against such tracking issues may be enabled in the 632 network side. Note, privacy extensions are required by regulatory 633 bodies in some countries. 635 Host-based validation of DNSSEC is discussed in A_REC#3 (see 636 Section 4). 638 6. IANA Considerations 640 This document does not require any action from IANA. 642 7. Acknowledgements 644 Many thanks to C. Byrne, H. Soliman, H. Singh, L. Colliti, T. 645 Lemon, B. Sarikaya, M. Mawatari, M. Abrahamsson, P. Vickers, V. 646 Kuarsingh, E. Kline, S. Josefsson, A. Baryun, J. Woodyatt, T. 647 Kossut, B. Stark, and A. Petrescu for the discussion in the v6ops 648 mailing list and for the comments. 650 Thanks to A. Farrel, B. Haberman and K. Moriarty for the comments 651 during the IESG review. 653 Special thanks to T. Savolainen, J. Korhonen, J. Jaeggli, and F. 654 Baker for their detailed reviews and comments. 656 8. References 658 8.1. Normative References 660 [IR92] GSMA, "IR.92.V4.0 - IMS Profile for Voice and SMS", March 661 2011, . 664 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 665 (IPv6) Specification", RFC 2460, December 1998. 667 [RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi, 668 "DNS Extensions to Support IP Version 6", RFC 3596, 669 October 2003. 671 [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic 672 Host Configuration Protocol (DHCP) version 6", RFC 3633, 673 December 2003. 675 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform 676 Resource Identifier (URI): Generic Syntax", STD 66, RFC 677 3986, January 2005. 679 [RFC5795] Sandlund, K., Pelletier, G., and L-E. Jonsson, "The RObust 680 Header Compression (ROHC) Framework", RFC 5795, March 681 2010. 683 [RFC5954] Gurbani, V., Carpenter, B., and B. Tate, "Essential 684 Correction for IPv6 ABNF and URI Comparison in RFC 3261", 685 RFC 5954, August 2010. 687 [RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X. 688 Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052, 689 October 2010. 691 [RFC6603] Korhonen, J., Savolainen, T., Krishnan, S., and O. Troan, 692 "Prefix Exclude Option for DHCPv6-based Prefix 693 Delegation", RFC 6603, May 2012. 695 [RFC7066] Korhonen, J., Arkko, J., Savolainen, T., and S. Krishnan, 696 "IPv6 for Third Generation Partnership Project (3GPP) 697 Cellular Hosts", RFC 7066, November 2013. 699 [TS.23060] 700 3GPP, "General Packet Radio Service (GPRS); Service 701 description; Stage 2", September 2011, 702 . 704 [TS.23401] 705 3GPP, "General Packet Radio Service (GPRS) enhancements 706 for Evolved Universal Terrestrial Radio Access Network 707 (E-UTRAN) access", September 2011, 708 . 710 [TS.24008] 711 3GPP, "Mobile radio interface Layer 3 specification; Core 712 network protocols; Stage 3", June 2011, 713 . 715 8.2. Informative References 717 [OECD] Organisation for Economic Cooperation and Development 718 (OECD), "The Economics of the Transition to Internet 719 Protocol version 6 (IPv6)", November 2014, . 723 [Power] Haverinen, H., Siren, J., and P. Eronen, "Energy 724 Consumption of Always-On Applications in WCDMA Networks", 725 April 2007, . 728 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 729 A., Peterson, J., Sparks, R., Handley, M., and E. 730 Schooler, "SIP: Session Initiation Protocol", RFC 3261, 731 June 2002. 733 [RFC3948] Huttunen, A., Swander, B., Volpe, V., DiBurro, L., and M. 734 Stenberg, "UDP Encapsulation of IPsec ESP Packets", RFC 735 3948, January 2005. 737 [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. 738 Rose, "DNS Security Introduction and Requirements", RFC 739 4033, March 2005. 741 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. 742 Rose, "Resource Records for the DNS Security Extensions", 743 RFC 4034, March 2005. 745 [RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. 746 Rose, "Protocol Modifications for the DNS Security 747 Extensions", RFC 4035, March 2005. 749 [RFC6092] Woodyatt, J., "Recommended Simple Security Capabilities in 750 Customer Premises Equipment (CPE) for Providing 751 Residential IPv6 Internet Service", RFC 6092, January 752 2011. 754 [RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation 755 Algorithm", RFC 6145, April 2011. 757 [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful 758 NAT64: Network Address and Protocol Translation from IPv6 759 Clients to IPv4 Servers", RFC 6146, April 2011. 761 [RFC6147] Bagnulo, M., Sullivan, A., Matthews, P., and I. van 762 Beijnum, "DNS64: DNS Extensions for Network Address 763 Translation from IPv6 Clients to IPv4 Servers", RFC 6147, 764 April 2011. 766 [RFC6434] Jankiewicz, E., Loughney, J., and T. Narten, "IPv6 Node 767 Requirements", RFC 6434, December 2011. 769 [RFC6459] Korhonen, J., Soininen, J., Patil, B., Savolainen, T., 770 Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation 771 Partnership Project (3GPP) Evolved Packet System (EPS)", 772 RFC 6459, January 2012. 774 [RFC6724] Thaler, D., Draves, R., Matsumoto, A., and T. Chown, 775 "Default Address Selection for Internet Protocol Version 6 776 (IPv6)", RFC 6724, September 2012. 778 [RFC6877] Mawatari, M., Kawashima, M., and C. Byrne, "464XLAT: 779 Combination of Stateful and Stateless Translation", RFC 780 6877, April 2013. 782 [RFC6887] Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P. 783 Selkirk, "Port Control Protocol (PCP)", RFC 6887, April 784 2013. 786 [RFC6889] Penno, R., Saxena, T., Boucadair, M., and S. Sivakumar, 787 "Analysis of Stateful 64 Translation", RFC 6889, April 788 2013. 790 [RFC7050] Savolainen, T., Korhonen, J., and D. Wing, "Discovery of 791 the IPv6 Prefix Used for IPv6 Address Synthesis", RFC 792 7050, November 2013. 794 [RFC7051] Korhonen, J. and T. Savolainen, "Analysis of Solution 795 Proposals for Hosts to Learn NAT64 Prefix", RFC 7051, 796 November 2013. 798 [RFC7084] Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic 799 Requirements for IPv6 Customer Edge Routers", RFC 7084, 800 November 2013. 802 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 803 Interface Identifiers with IPv6 Stateless Address 804 Autoconfiguration (SLAAC)", RFC 7217, April 2014. 806 [RFC7225] Boucadair, M., "Discovering NAT64 IPv6 Prefixes Using the 807 Port Control Protocol (PCP)", RFC 7225, May 2014. 809 [RFC7278] Byrne, C., Drown, D., and A. Vizdal, "Extending an IPv6 810 /64 Prefix from a Third Generation Partnership Project 811 (3GPP) Mobile Interface to a LAN Link", RFC 7278, June 812 2014. 814 [RFC7335] Byrne, C., "IPv4 Service Continuity Prefix", RFC 7335, 815 August 2014. 817 [RFC7445] Chen, G., Deng, H., Michaud, D., Korhonen, J., Boucadair, 818 M., and V. Ales, "Analysis of Failure Cases in IPv6 819 Roaming Scenarios", February 2015. 821 [TS.23402] 822 3GPP, "Architecture enhancements for non-3GPP accesses", 823 September 2011, 824 . 826 Authors' Addresses 828 David Binet 829 France Telecom 830 Rennes 831 France 833 EMail: david.binet@orange.com 835 Mohamed Boucadair 836 France Telecom 837 Rennes 35000 838 France 840 EMail: mohamed.boucadair@orange.com 842 Ales Vizdal 843 Deutsche Telekom AG 845 EMail: ales.vizdal@t-mobile.cz 847 Gang Chen 848 China Mobile 850 EMail: phdgang@gmail.com 851 Nick Heatley 852 EE 853 The Point, 37 North Wharf Road, 854 London W2 1AG 855 U.K 857 EMail: nick.heatley@ee.co.uk 859 Ross Chandler 860 eircom | meteor 861 1HSQ 862 St. John's Road 863 Dublin 8 864 Ireland 866 EMail: ross@eircom.net 868 Dave Michaud 869 Rogers Communications 870 8200 Dixie Rd. 871 Brampton, ON L6T 0C1 872 Canada 874 EMail: dave.michaud@rci.rogers.com 876 Diego R. Lopez 877 Telefonica I+D 878 Don Ramon de la Cruz, 82 879 Madrid 28006 880 Spain 882 Phone: +34 913 129 041 883 EMail: diego.r.lopez@telefonica.com