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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-05 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-05 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-05 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. As in this case, the UE may be any device that can be function 84 as an IPv6 router. 86 This document describes three methods for achieving IPv6 prefix 87 extension from a 3GPP radio interface to a LAN including: 89 1) The 3GPP UE does not have a global scope IPv6 address on any 90 interface, only link-local IPv6 addresses are present on the UE 91 2) The 3GPP UE only has a global scope address on the LAN interface 92 3) The 3GPP UE maintains the same consistent 128 bit global scope 93 IPv6 anycast address [RFC4291] on the 3GPP radio interface and the 94 LAN interface. The LAN interface is configured as a /64 and the 95 3GPP radio interface is configured as a /128. 97 Section 3 describes the characteristics of each of the three 98 approaches. 100 2. The Challenge of Providing IPv6 Addresses to a LAN via a 3GPP UE 102 As described in [RFC6459], 3GPP networks assign a /64 global scope 103 prefix to each UE using RA. DHCPv6 Prefix Delegation is an optional 104 part of 3GPP Release-10 and is not covered by any earlier releases. 105 Neighbor Discovery Proxy (ND Proxy) [RFC4389] functionality has been 106 suggested as an option for extending the assigned /64 from the 3GPP 107 radio interface to the LAN, but ND Proxy is an experimental protocol 108 and has some limitations with loop-avoidance. 110 DHCPv6 is the best way to delegate a prefix to a LAN. The methods 111 described in this document should only be applied when deploying 112 DHCPv6 Prefix Delegation is not achievable in the 3GPP network and 113 the UE. The methods described in this document are at various stages 114 of implementation and deployment planning. The goal of the document 115 is create a common understanding of the available methods which may 116 used prior to DHCPv6 deployment. 118 V6OPS Working Group draft-ietf-v6ops-64share-05 May 17, 2013 120 3. Methods for Extending the 3GPP Interface /64 IPv6 Prefix to a LAN 122 3.0 General Behavior for All Scenarios 124 As [RFC6459] describes, the 3GPP network assigned /64 is completely 125 dedicated to the UE and the gateway does not consume any of the /64 126 addresses. The gateway routes the entire /64 to the UE and does not 127 perform ND or Network Unreachability Detection (NUD) [RFC4861]. 128 Communication between the UE and the gateway is only done using link- 129 local addresses and the link is point-to-point. This allows for the 130 UE to reliably manipulate the /64 from the 3GPP radio interface 131 without negatively impacting the point-to-point 3GPP radio link 132 interface. The LAN interface RA configuration must be tightly 133 coupled with the 3GPP interface state. If the 3GPP interface goes 134 down or changes the IPv6 prefix, that state should be reflected in 135 the LAN IPv6 configuration. Just as in a standard IPv6 router, the 136 packet TTL will be decremented when passing packets between 137 interfaces across the UE. The RA function on the UE is exclusively 138 run on the LAN interface. 140 3.1 Scenario 1: No Global Address on the UE 142 In this case, the UE receives the /64 from the 3GPP network via RA 143 and simply configures Neighbor Discovery Protocol (NDP) [RFC4861] on 144 the LAN interface to announce the /64 via RA. The UE forwards all 145 traffic destine to the /64 out of the LAN interface. The UE shall 146 not run Stateless Address Autoconfiguration [RFC4862] to assign a 147 global address on the 3GPP radio interface while routing is enabled. 148 The 3GPP UE does not assign itself any global IPv6 addresses. Lack 149 of global scope connectivity will limit network services running on 150 the UE (e.g. DNS caching that requires global connectivity) and 151 prevent proper Path MTU Discovery [RFC1981] to occur on the UE. The 152 LAN attached devices have complete access to the /64, but the 3GPP UE 153 only has link-local addresses. 155 This method is appropriate for a use-case where the UE is only an 156 IPv6 router that does not require any global connectivity. 158 Below is the general procedure for this scenario: 160 1. The user activates router functionality for a LAN on the UE. 162 2. The UE checks to make sure the 3GPP interface is active and has 163 an IPv6 address. If the interface does not have an IPv6 address, 164 an attempt will be made to acquire one, or else the procedure 165 will terminate. 167 V6OPS Working Group draft-ietf-v6ops-64share-05 May 17, 2013 169 3. In this example, the UE finds the 3GPP interface has the IPv6 170 address 2001:db8:ac10:f002:1234:4567:0:9/64 assigned and active. 172 4. The UE copies the prefix 2001:db8:ac10:f002::/64 from the 3GPP 173 interface to the LAN interface, removes the global IPv6 address 174 configuration from the 3GPP radio interface, disables the IPv6 175 Stateless Address Autoconfiguration (SLAAC) [RFC4862] feature for 176 global addresses on the 3GPP radio interface to avoid address 177 autoconfiguration, and begins announcing the global prefix 178 2001:db8:ac10:f002::/64 via RA to the LAN. The 3GPP interface 179 and LAN interface only maintain link-local addresses while the UE 180 uses RA to announce the /64 to the LAN. 182 5. Since the UE and gateway do not assign any of the addresses from 183 the /64, there is no chance of an address conflict on the 3GPP 184 radio interface. On the LAN interface, there is no chance of an 185 address conflict since the hosts on the LAN will use Duplicate 186 Address Detection (DAD) [RFC4862]. 188 3.2 Scenario 2: Global Address Only Assigned to LAN 190 For this case, the UE receives the RA from the 3GPP network but does 191 not use a global address on the 3GPP interface. The 3GPP RA /64 192 prefix information is used to configure NDP on the LAN and assigns 193 itself an address on the LAN link. The LAN interface uses RA to 194 announce the prefix to the LAN. The UE LAN interface defends its LAN 195 IPv6 address with DAD. The UE shall not run Stateless Address 196 Autoconfiguration [RFC4862] to assign a global address on the 3GPP 197 radio interface while routing is enabled. 199 This method allows the UE to originate and terminate IPv6 200 communications as a host while acting as an IPv6 router. The 201 movement of the IPv6 prefix from the 3GPP radio interface to the LAN 202 interface may result in long-lived data connections being terminated 203 during the transition from a host-only mode to router-and-host mode. 204 This method is appropriate if the UE or software on the UE cannot 205 support multiple interfaces with the same anycast IPv6 address and 206 the UE requires global connectivity while acting as a router. 208 Below is the general procedure for this scenario: 210 1. The user activates router functionality for a LAN on the UE. 212 2. The UE checks to make sure the 3GPP interface is active and has 213 an IPv6 address. If the interface does not have an IPv6 address, 214 an attempt will be made to acquire one, or else the procedure 215 will terminate. 217 V6OPS Working Group draft-ietf-v6ops-64share-05 May 17, 2013 219 3. In this example, the UE finds the 3GPP interface has the IPv6 220 address 2001:db8:ac10:f002:1234:4567:0:9 assigned and active. 222 4. The UE moves the address 2001:db8:ac10:f002:1234:4567:0:9 as a 223 /64 from the 3GPP interfaces to the LAN interface, disables the 224 IPv6 SLAAC feature on the 3GPP radio interface to avoid address 225 autoconfiguration, and begins announcing the prefix 226 2001:db8:ac10:f002::/64 via RA to the LAN. For this example, the 227 LAN has 2001:db8:ac10:f002:1234:4567:0:9/64 and the 3GPP radio 228 only has a link-local address. 230 5. The UE directly processes all packets destined to itself at 231 2001:db8:ac10:f002:1234:4567:0:9. 233 6. The UE, acting as a router running NDP on the LAN, will route 234 packets to and from the LAN. IPv6 packets passing between 235 interfaces will have the TTL decremented. 237 7. On the LAN interface, there is no chance of address conflict 238 since the address is defended using DAD. The 3GPP radio 239 interface only has link-local addresses. 241 3.3 Scenario 3: A Single Global Address Assigned to 3GPP Radio and LAN 242 Interface 244 In this method, the UE assigns itself one address from the 3GPP 245 network RA announced /64. This one address is configured as anycast 246 [RFC4291] on both the 3GPP radio interface as a /128 and on the LAN 247 interface as a /64. This allows the UE to maintain long lived data 248 connections since the 3GPP radio interface address does not change 249 when the router function is activated. This method may cause 250 complications for certain software that may not support multiple 251 interfaces with the same anycast IPv6 address or are sensitive to 252 prefix length changes. This method also creates complications for 253 ensuring uniqueness for Privacy Extensions [RFC4941]. Privacy 254 Extensions should be disabled on the 3GPP radio interface while this 255 method is enabled. 257 There might also be more complex scenarios in which the prefix length 258 is not changed and privacy extensions are supported by having the 259 subnet span multiple interfaces, as ND Proxy does [RFC4389]. Further 260 elaboration is out of scope of the present document. 262 Below is the general procedure for this scenario: 264 V6OPS Working Group draft-ietf-v6ops-64share-05 May 17, 2013 266 1. The user activates router functionality for a LAN on the UE. 268 2. The UE checks to make sure the 3GPP interfaces is active and has 269 an IPv6 address. If the interface does not have an IPv6 address, 270 an attempt will be made to acquire one, or else the procedure 271 will terminate. 273 3. In this example, the UE finds the 3GPP interface has the IPv6 274 address 2001:db8:ac10:f002:1234:4567:0:9 assigned and active. 276 4. The UE moves the address 2001:db8:ac10:f002:1234:4567:0:9 as an 277 anycast /64 from the 3GPP interface to the LAN interface and 278 begins announcing the prefix 2001:db8:ac10:f002::/64 via RA to 279 the LAN. The 3GPP interface maintains the same IPv6 anycast 280 address with a /128. For this example, the LAN has 281 2001:db8:ac10:f002:1234:4567:0:9/64 and the 3GPP radio interface 282 has 2001:db8:ac10:f002:1234:4567:0:9/128. 284 5. The UE directly processes all packets destined to itself at 285 2001:db8:ac10:f002:1234:4567:0:9. 287 6. On the LAN interface, there is no chance of address conflict 288 since the address is defended using DAD. The 3GPP radio 289 interface only has a /128 and no other systems on the 3GPP radio 290 point-to-point link may use the global /64. 292 4. Security Considerations 294 Since Scenario 3.3 does not allow for Privacy Extension to run on the 295 3GPP interface, UEs that require this functionality must find an 296 alternative method or only associate the IPv6 Privacy Extension 297 procedure on the LAN. 299 5. IANA Considerations 301 This document does not require any action from IANA. 303 6. Acknowledgments 305 Many thanks for review and discussion from Dave Thaler, Sylvain 306 Decremps, Mark Smith, Dmitry Anipko, Masanobu Kawashima, Teemu 307 Savolainen, Mikael Abrahamsson, Eric Vyncke, Alexandru Petrescu, 308 Jouni Korhonen, and Julien Laganier. 310 7. Informative References 312 [RFC1981] McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery 314 V6OPS Working Group draft-ietf-v6ops-64share-05 May 17, 2013 316 for IP version 6", RFC 1981, August 1996. 318 [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic 319 Host Configuration Protocol (DHCP) version 6", RFC 3633, 320 December 2003. 322 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 323 Architecture", RFC 4291, February 2006. 325 [RFC4389] Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery 326 Proxies (ND Proxy)", RFC 4389, April 2006. 328 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 329 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 330 September 2007. 332 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 333 Address Autoconfiguration", RFC 4862, September 2007. 335 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy 336 Extensions for Stateless Address Autoconfiguration in 337 IPv6", RFC 4941, September 2007. 339 [RFC6459] Korhonen, J., Ed., Soininen, J., Patil, B., Savolainen, 340 T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation 341 Partnership Project (3GPP) Evolved Packet System (EPS)", 342 RFC 6459, January 2012. 344 Authors' Addresses 346 Cameron Byrne 347 T-Mobile USA 348 Bellevue, Washington, USA 349 EMail: Cameron.Byrne@T-Mobile.com 351 Dan Drown 352 Email: Dan@Drown.org 354 Ales Vizdal 355 Deutsche Telekom AG 356 Tomickova 2144/1 357 Prague, 149 00 358 Czech Republic 359 EMail: Ales.Vizdal@t-mobile.cz