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Checking references for intended status: Informational ---------------------------------------------------------------------------- -- Obsolete informational reference (is this intentional?): RFC 1981 (Obsoleted by RFC 8201) -- Obsolete informational reference (is this intentional?): RFC 3633 (Obsoleted by RFC 8415) -- Obsolete informational reference (is this intentional?): RFC 4941 (Obsoleted by RFC 8981) Summary: 0 errors (**), 0 flaws (~~), 7 warnings (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 V6OPS Working Group C. Byrne 3 Internet-Draft T-Mobile USA 4 Intended Status: Informational D. Drown 5 Expires: November 18, 2013 A. Vizdal 6 Deutsche Telekom AG 7 May 17, 2013 9 Extending an IPv6 /64 Prefix from a 3GPP Mobile Interface to a LAN 10 draft-ietf-v6ops-64share-06 12 Abstract 14 This document describes three methods for extending an IPv6 /64 15 prefix from a User Equipment 3GPP radio interface to a LAN. 17 Status of this Memo 19 This Internet-Draft is submitted in full conformance with the 20 provisions of BCP 78 and BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF). Note that other groups may also distribute 24 working documents as Internet-Drafts. The list of current Internet- 25 Drafts is at http://datatracker.ietf.org/drafts/current/. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 This Internet-Draft will expire on November 18, 2013. 34 Copyright and License Notice 36 Copyright (c) 2013 IETF Trust and the persons identified as the 37 document authors. All rights reserved. 39 This document is subject to BCP 78 and the IETF Trust's Legal 40 Provisions Relating to IETF Documents 41 (http://trustee.ietf.org/license-info) in effect on the date of 42 publication of this document. Please review these documents 43 carefully, as they describe your rights and restrictions with respect 44 to this document. Code Components extracted from this document must 45 include Simplified BSD License text as described in Section 4.e of 46 the Trust Legal Provisions and are provided without warranty as 47 described in the Simplified BSD License. 49 V6OPS Working Group draft-ietf-v6ops-64share-06 May 17, 2013 51 Table of Contents 53 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 54 2. The Challenge of Providing IPv6 Addresses to a LAN via a 3GPP 55 UE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 56 3. Methods for Extending the 3GPP Interface /64 IPv6 Prefix to a 57 LAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 58 3.0 General Behavior for All Scenarios . . . . . . . . . . . . . 4 59 3.1 Scenario 1: No Global Address on the UE . . . . . . . . . . 4 60 3.2 Scenario 2: Global Address Only Assigned to LAN . . . . . . 5 61 3.3 Scenario 3: A Single Global Address Assigned to 3GPP Radio 62 and LAN Interface . . . . . . . . . . . . . . . . . . . . . 6 63 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 64 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 65 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7 66 7. Informative References . . . . . . . . . . . . . . . . . . . . 7 68 V6OPS Working Group draft-ietf-v6ops-64share-06 May 17, 2013 70 1. Introduction 72 3GPP mobile cellular networks such as GSM, UMTS, and LTE have 73 architectural support for IPv6 [RFC6459], but only 3GPP Release-10 74 and onwards of the 3GPP specification supports DHCPv6 Prefix 75 Delegation [RFC3633] for delegating IPv6 prefixes to a LAN. To 76 facilitate the use of IPv6 in a LAN prior to the deployment of DHCPv6 77 Prefix Delegation in 3GPP networks and in User Equipment (UE), this 78 document describes how the 3GPP UE radio interface assigned global 79 /64 prefix may be extended from the 3GPP radio interface to a LAN. 80 This is achieved by receiving the Router Advertisement (RA) [RFC4861] 81 announced globally unique /64 IPv6 prefix from the 3GPP radio 82 interface and then advertising the same IPv6 prefix to the LAN with 83 RA. For all of the cases in the scope of this document, the UE may 84 be any device that function as an IPv6 router between the 3GPP 85 network and a LAN. 87 This document describes three methods for achieving IPv6 prefix 88 extension from a 3GPP radio interface to a LAN including: 90 1) The 3GPP UE does not have a global scope IPv6 address on any 91 interface, only link-local IPv6 addresses are present on the UE 92 2) The 3GPP UE only has a global scope address on the LAN interface 93 3) The 3GPP UE maintains the same consistent 128 bit global scope 94 IPv6 anycast address [RFC4291] on the 3GPP radio interface and the 95 LAN interface. The LAN interface is configured as a /64 and the 96 3GPP radio interface is configured as a /128. 98 Section 3 describes the characteristics of each of the three 99 approaches. 101 2. The Challenge of Providing IPv6 Addresses to a LAN via a 3GPP UE 103 As described in [RFC6459], 3GPP networks assign a /64 global scope 104 prefix to each UE using RA. DHCPv6 Prefix Delegation is an optional 105 part of 3GPP Release-10 and is not covered by any earlier releases. 106 Neighbor Discovery Proxy (ND Proxy) [RFC4389] functionality has been 107 suggested as an option for extending the assigned /64 from the 3GPP 108 radio interface to the LAN, but ND Proxy is an experimental protocol 109 and has some limitations with loop-avoidance. 111 DHCPv6 is the best way to delegate a prefix to a LAN. The methods 112 described in this document should only be applied when deploying 113 DHCPv6 Prefix Delegation is not achievable in the 3GPP network and 114 the UE. The methods described in this document are at various stages 115 of implementation and deployment planning. The goal of this memo is 116 to document the available methods which may used prior to DHCPv6 117 deployment. 119 V6OPS Working Group draft-ietf-v6ops-64share-06 May 17, 2013 121 3. Methods for Extending the 3GPP Interface /64 IPv6 Prefix to a LAN 123 3.0 General Behavior for All Scenarios 125 As [RFC6459] describes, the 3GPP network assigned /64 is completely 126 dedicated to the UE and the gateway does not consume any of the /64 127 addresses. The gateway routes the entire /64 to the UE and does not 128 perform ND or Network Unreachability Detection (NUD) [RFC4861]. 129 Communication between the UE and the gateway is only done using link- 130 local addresses and the link is point-to-point. This allows for the 131 UE to reliably manipulate the /64 from the 3GPP radio interface 132 without negatively impacting the point-to-point 3GPP radio link 133 interface. The LAN interface RA configuration must be tightly 134 coupled with the 3GPP interface state. If the 3GPP interface goes 135 down or changes the IPv6 prefix, that state should be reflected in 136 the LAN IPv6 configuration. Just as in a standard IPv6 router, the 137 packet TTL will be decremented when passing packets between 138 interfaces across the UE. The RA function on the UE is exclusively 139 run on the LAN interface. 141 3.1 Scenario 1: No Global Address on the UE 143 In this case, the UE receives the /64 from the 3GPP network via RA 144 and simply configures Neighbor Discovery Protocol (NDP) [RFC4861] on 145 the LAN interface to announce the /64 via RA. The UE forwards all 146 traffic destine to the /64 out of the LAN interface. The UE shall 147 not run Stateless Address Autoconfiguration [RFC4862] to assign a 148 global address on the 3GPP radio interface while routing is enabled. 149 The 3GPP UE does not assign itself any global IPv6 addresses. Lack 150 of global scope connectivity will limit network services running on 151 the UE (e.g. DNS caching that requires global connectivity) and 152 prevent proper Path MTU Discovery [RFC1981] to occur on the UE 153 providing an IPv6 router function. The LAN attached devices have 154 complete access to the /64, but the 3GPP UE only has link-local 155 addresses. 157 This method is appropriate for a use-case where the UE is only an 158 IPv6 router that does not require any global connectivity. 160 Below is the general procedure for this scenario: 162 1. The user activates router functionality for a LAN on the UE. 164 2. The UE checks to make sure the 3GPP interface is active and has 165 an IPv6 address. If the interface does not have an IPv6 address, 166 an attempt will be made to acquire one, or else the procedure 167 will terminate. 169 V6OPS Working Group draft-ietf-v6ops-64share-06 May 17, 2013 171 3. In this example, the UE finds the 3GPP interface has the IPv6 172 address 2001:db8:ac10:f002:1234:4567:0:9/64 assigned and active. 174 4. The UE copies the prefix 2001:db8:ac10:f002::/64 from the 3GPP 175 interface to the LAN interface, removes the global IPv6 address 176 configuration from the 3GPP radio interface, disables the IPv6 177 Stateless Address Autoconfiguration (SLAAC) [RFC4862] feature for 178 global addresses on the 3GPP radio interface to avoid address 179 autoconfiguration, and begins announcing the global prefix 180 2001:db8:ac10:f002::/64 via RA to the LAN. The 3GPP interface 181 and LAN interface only maintain link-local addresses while the UE 182 uses RA to announce the /64 to the LAN. 184 5. Since the UE and gateway do not assign any of the addresses from 185 the /64, there is no chance of an address conflict on the 3GPP 186 radio interface. On the LAN interface, there is no chance of an 187 address conflict since the hosts on the LAN will use Duplicate 188 Address Detection (DAD) [RFC4862]. 190 3.2 Scenario 2: Global Address Only Assigned to LAN 192 For this case, the UE receives the RA from the 3GPP network but does 193 not use a global address on the 3GPP interface. The 3GPP RA /64 194 prefix information is used to configure NDP on the LAN and assigns 195 itself an address on the LAN link. The LAN interface uses RA to 196 announce the prefix to the LAN. The UE LAN interface defends its LAN 197 IPv6 address with DAD. The UE shall not run Stateless Address 198 Autoconfiguration [RFC4862] to assign a global address on the 3GPP 199 radio interface while routing is enabled. 201 This method allows the UE to originate and terminate IPv6 202 communications as a host while acting as an IPv6 router. The 203 movement of the IPv6 prefix from the 3GPP radio interface to the LAN 204 interface may result in long-lived data connections being terminated 205 during the transition from a host-only mode to router-and-host mode. 206 This method is appropriate if the UE or software on the UE cannot 207 support multiple interfaces with the same anycast IPv6 address and 208 the UE requires global connectivity while acting as a router. 210 Below is the general procedure for this scenario: 212 1. The user activates router functionality for a LAN on the UE. 214 2. The UE checks to make sure the 3GPP interface is active and has 215 an IPv6 address. If the interface does not have an IPv6 address, 216 an attempt will be made to acquire one, or else the procedure 217 will terminate. 219 V6OPS Working Group draft-ietf-v6ops-64share-06 May 17, 2013 221 3. In this example, the UE finds the 3GPP interface has the IPv6 222 address 2001:db8:ac10:f002:1234:4567:0:9 assigned and active. 224 4. The UE moves the address 2001:db8:ac10:f002:1234:4567:0:9 as a 225 /64 from the 3GPP interfaces to the LAN interface, disables the 226 IPv6 SLAAC feature on the 3GPP radio interface to avoid address 227 autoconfiguration, and begins announcing the prefix 228 2001:db8:ac10:f002::/64 via RA to the LAN. For this example, the 229 LAN has 2001:db8:ac10:f002:1234:4567:0:9/64 and the 3GPP radio 230 only has a link-local address. 232 5. The UE directly processes all packets destined to itself at 233 2001:db8:ac10:f002:1234:4567:0:9. 235 6. The UE, acting as a router running NDP on the LAN, will route 236 packets to and from the LAN. IPv6 packets passing between 237 interfaces will have the TTL decremented. 239 7. On the LAN interface, there is no chance of address conflict 240 since the address is defended using DAD. The 3GPP radio 241 interface only has link-local addresses. 243 3.3 Scenario 3: A Single Global Address Assigned to 3GPP Radio and LAN 244 Interface 246 In this method, the UE assigns itself one address from the 3GPP 247 network RA announced /64. This one address is configured as anycast 248 [RFC4291] on both the 3GPP radio interface as a /128 and on the LAN 249 interface as a /64. This allows the UE to maintain long lived data 250 connections since the 3GPP radio interface address does not change 251 when the router function is activated. This method may cause 252 complications for certain software that may not support multiple 253 interfaces with the same anycast IPv6 address or are sensitive to 254 prefix length changes. This method also creates complications for 255 ensuring uniqueness for Privacy Extensions [RFC4941]. Privacy 256 Extensions should be disabled on the 3GPP radio interface while this 257 method is enabled. 259 There might also be more complex scenarios in which the prefix length 260 is not changed and privacy extensions are supported by having the 261 subnet span multiple interfaces, as ND Proxy does [RFC4389]. Further 262 elaboration is out of scope of the present document. 264 Below is the general procedure for this scenario: 266 V6OPS Working Group draft-ietf-v6ops-64share-06 May 17, 2013 268 1. The user activates router functionality for a LAN on the UE. 270 2. The UE checks to make sure the 3GPP interfaces is active and has 271 an IPv6 address. If the interface does not have an IPv6 address, 272 an attempt will be made to acquire one, or else the procedure 273 will terminate. 275 3. In this example, the UE finds the 3GPP interface has the IPv6 276 address 2001:db8:ac10:f002:1234:4567:0:9 assigned and active. 278 4. The UE moves the address 2001:db8:ac10:f002:1234:4567:0:9 as an 279 anycast /64 from the 3GPP interface to the LAN interface and 280 begins announcing the prefix 2001:db8:ac10:f002::/64 via RA to 281 the LAN. The 3GPP interface maintains the same IPv6 anycast 282 address with a /128. For this example, the LAN has 283 2001:db8:ac10:f002:1234:4567:0:9/64 and the 3GPP radio interface 284 has 2001:db8:ac10:f002:1234:4567:0:9/128. 286 5. The UE directly processes all packets destined to itself at 287 2001:db8:ac10:f002:1234:4567:0:9. 289 6. On the LAN interface, there is no chance of address conflict 290 since the address is defended using DAD. The 3GPP radio 291 interface only has a /128 and no other systems on the 3GPP radio 292 point-to-point link may use the global /64. 294 4. Security Considerations 296 Since Scenario 3.3 does not allow for Privacy Extension to run on the 297 3GPP interface, UEs that require this functionality must find an 298 alternative method or only associate the IPv6 Privacy Extension 299 procedure on the LAN. 301 5. IANA Considerations 303 This document does not require any action from IANA. 305 6. Acknowledgments 307 Many thanks for review and discussion from Dave Thaler, Sylvain 308 Decremps, Mark Smith, Dmitry Anipko, Masanobu Kawashima, Teemu 309 Savolainen, Mikael Abrahamsson, Eric Vyncke, Alexandru Petrescu, 310 Jouni Korhonen, and Julien Laganier. 312 7. Informative References 314 [RFC1981] McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery 316 V6OPS Working Group draft-ietf-v6ops-64share-06 May 17, 2013 318 for IP version 6", RFC 1981, August 1996. 320 [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic 321 Host Configuration Protocol (DHCP) version 6", RFC 3633, 322 December 2003. 324 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 325 Architecture", RFC 4291, February 2006. 327 [RFC4389] Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery 328 Proxies (ND Proxy)", RFC 4389, April 2006. 330 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 331 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 332 September 2007. 334 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 335 Address Autoconfiguration", RFC 4862, September 2007. 337 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy 338 Extensions for Stateless Address Autoconfiguration in 339 IPv6", RFC 4941, September 2007. 341 [RFC6459] Korhonen, J., Ed., Soininen, J., Patil, B., Savolainen, 342 T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation 343 Partnership Project (3GPP) Evolved Packet System (EPS)", 344 RFC 6459, January 2012. 346 Authors' Addresses 348 Cameron Byrne 349 T-Mobile USA 350 Bellevue, Washington, USA 351 EMail: Cameron.Byrne@T-Mobile.com 353 Dan Drown 354 Email: Dan@Drown.org 356 Ales Vizdal 357 Deutsche Telekom AG 358 Tomickova 2144/1 359 Prague, 149 00 360 Czech Republic 361 EMail: Ales.Vizdal@t-mobile.cz