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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Missing Reference: 'RFC6459' is mentioned on line 117, but not defined == Unused Reference: 'RFC1981' is defined on line 260, but no explicit reference was found in the text -- 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 (~~), 3 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: January 15, 2014 A. Vizdal 6 Deutsche Telekom AG 7 July 14, 2013 9 Extending an IPv6 /64 Prefix from a 3GPP Mobile Interface to a LAN link 10 draft-ietf-v6ops-64share-08 12 Abstract 14 This document describes two methods for extending an IPv6 /64 prefix 15 from a User Equipment 3GPP radio interface to a LAN link. 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 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 52 2. The Challenge of Providing IPv6 Addresses to a LAN link via a 53 3GPP UE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 54 3. Methods for Extending the 3GPP Interface /64 IPv6 Prefix to a 55 LAN link . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 56 3.1 General Behavior for All Scenarios . . . . . . . . . . . . . 4 57 3.2 Scenario 1: Global Address Only Assigned to LAN link . . . . 4 58 3.3 Scenario 2: A Single Global Address Assigned to 3GPP Radio 59 and LAN link . . . . . . . . . . . . . . . . . . . . . . . . 5 60 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 61 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 62 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 6 63 7. Informative References . . . . . . . . . . . . . . . . . . . . 7 65 1. Introduction 67 3GPP mobile cellular networks such as GSM, UMTS, and LTE have 68 architectural support for IPv6 [RFC6459], but only 3GPP Release-10 69 and onwards of the 3GPP specification supports DHCPv6 Prefix 70 Delegation [RFC3633] for delegating IPv6 prefixes to a single LAN 71 link. To facilitate the use of IPv6 in a LAN prior to the deployment 72 of DHCPv6 Prefix Delegation in 3GPP networks and in User Equipment 73 (UE), this document describes how the 3GPP UE radio interface 74 assigned global /64 prefix may be extended from the 3GPP radio 75 interface to a LAN link. This is achieved by receiving the Router 76 Advertisement (RA) [RFC4861] announced globally unique /64 IPv6 77 prefix from the 3GPP radio interface and then advertising the same 78 IPv6 prefix to the LAN link with RA. For all of the cases in the 79 scope of this document, the UE may be any device that functions as an 80 IPv6 router between the 3GPP network and a LAN. 82 This document describes two methods for achieving IPv6 prefix 83 extension from a 3GPP radio interface to a LAN link including: 85 1) The 3GPP UE only has a global scope address on the LAN link 86 2) The 3GPP UE maintains the same consistent 128 bit global scope 87 IPv6 anycast address [RFC4291] on the 3GPP radio interface and the 88 LAN link. The LAN link is configured as a /64 and the 3GPP radio 89 interface is configured as a /128. 91 Section 3 describes the characteristics of each of the two 92 approaches. 94 2. The Challenge of Providing IPv6 Addresses to a LAN link via a 3GPP UE 96 As described in [RFC6459], 3GPP networks assign a /64 global scope 97 prefix to each UE using RA. DHCPv6 Prefix Delegation is an optional 98 part of 3GPP Release-10 and is not covered by any earlier releases. 99 Neighbor Discovery Proxy (ND Proxy) [RFC4389] functionality has been 100 suggested as an option for extending the assigned /64 from the 3GPP 101 radio interface to the LAN link, but ND Proxy is an experimental 102 protocol and has some limitations with loop-avoidance. 104 DHCPv6 is the best way to delegate a prefix to a LAN link. The 105 methods described in this document should only be applied when 106 deploying DHCPv6 Prefix Delegation is not achievable in the 3GPP 107 network and the UE. The methods described in this document are at 108 various stages of implementation and deployment planning. The goal 109 of this memo is to document the available methods which may be used 110 prior to DHCPv6 deployment. 112 3. Methods for Extending the 3GPP Interface /64 IPv6 Prefix to a LAN 113 link 115 3.1 General Behavior for All Scenarios 117 As [RFC6459] describes, the 3GPP network assigned /64 is completely 118 dedicated to the UE and the gateway does not consume any of the /64 119 addresses. The gateway routes the entire /64 to the UE and does not 120 perform ND or Network Unreachability Detection (NUD) [RFC4861]. 121 Communication between the UE and the gateway is only done using link- 122 local addresses and the link is point-to-point. This allows for the 123 UE to reliably manipulate the /64 from the 3GPP radio interface 124 without negatively impacting the point-to-point 3GPP radio link 125 interface. The LAN link RA configuration must be tightly coupled 126 with the 3GPP link state. If the 3GPP link goes down or changes the 127 IPv6 prefix, that state should be reflected in the LAN link IPv6 128 configuration. Just as in a standard IPv6 router, the packet TTL 129 will be decremented when passing packets between IPv6 links across 130 the UE. The UE is employing the weak host model. The RA function on 131 the UE is exclusively run on the LAN link. 133 The LAN link originated RA message carries a copy of the following 134 3GPP radio link received RA message option fields: 136 o MTU (if not provided by the 3GPP network, the UE will provide its 137 3GPP link MTU size) 138 o Prefix Information 140 3.2 Scenario 1: Global Address Only Assigned to LAN link 142 For this case, the UE receives the RA from the 3GPP network but does 143 not use a global address on the 3GPP interface. The 3GPP RA /64 144 prefix information is used to configure NDP on the LAN and assigns 145 itself an address on the LAN link. The LAN link uses RA to announce 146 the prefix to the LAN. The UE LAN link interface defends its LAN 147 IPv6 address with DAD. The UE shall not run Stateless Address 148 Autoconfiguration [RFC4862] to assign a global address on the 3GPP 149 radio interface while routing is enabled. 151 This method allows the UE to originate and terminate IPv6 152 communications as a host while acting as an IPv6 router. The 153 movement of the IPv6 prefix from the 3GPP radio interface to the LAN 154 link may result in long-lived data connections being terminated 155 during the transition from a host-only mode to router-and-host mode. 156 Connections which are likely to be effected are ones that have been 157 specifically bound to the 3GPP radio interface. This method is 158 appropriate if the UE or software on the UE cannot support multiple 159 interfaces with the same anycast IPv6 address and the UE requires 160 global connectivity while acting as a router. 162 Below is the general procedure for this scenario: 164 1. The user activates router functionality for a LAN on the UE. 166 2. The UE checks to make sure the 3GPP interface is active and has 167 an IPv6 address. If the interface does not have an IPv6 address, 168 an attempt will be made to acquire one, or else the procedure 169 will terminate. 171 3. In this example, the UE finds the 3GPP interface has the IPv6 172 address 2001:db8:ac10:f002:1234:4567:0:9 assigned and active. 174 4. The UE moves the address 2001:db8:ac10:f002:1234:4567:0:9 as a 175 /64 from the 3GPP interfaces to the LAN link interface, disables 176 the IPv6 SLAAC feature on the 3GPP radio interface to avoid 177 address autoconfiguration, and begins announcing the prefix 178 2001:db8:ac10:f002::/64 via RA to the LAN. For this example, the 179 LAN has 2001:db8:ac10:f002:1234:4567:0:9/64 and the 3GPP radio 180 only has a link-local address. 182 5. The UE directly processes all packets destined to itself at 183 2001:db8:ac10:f002:1234:4567:0:9. 185 6. The UE, acting as a router running NDP on the LAN, will route 186 packets to and from the LAN. IPv6 packets passing between 187 interfaces will have the TTL decremented. 189 7. On the LAN link interface, there is no chance of address conflict 190 since the address is defended using DAD. The 3GPP radio 191 interface only has a link-local address. 193 3.3 Scenario 2: A Single Global Address Assigned to 3GPP Radio and LAN 194 link 196 In this method, the UE assigns itself one address from the 3GPP 197 network RA announced /64. This one address is configured as anycast 198 [RFC4291] on both the 3GPP radio link as a /128 and on the LAN link 199 as a /64. This allows the UE to maintain long lived data connections 200 since the 3GPP radio interface address does not change when the 201 router function is activated. This method may cause complications 202 for certain software that may not support multiple interfaces with 203 the same anycast IPv6 address or are sensitive to prefix length 204 changes. This method also creates complications for ensuring 205 uniqueness for Privacy Extensions [RFC4941]. When Privacy Extensions 206 are in use all temporary addresses will be copied from the 3GPP radio 207 interface to the LAN link and the preferred and valid lifetimes will 208 be synchronized, such that the temporary anycast addresses on both 209 interfaces expire simultaneously. 211 There might also be more complex scenarios in which the prefix length 212 is not changed and privacy extensions are supported by having the 213 subnet span multiple interfaces, as ND Proxy does [RFC4389]. Further 214 elaboration is out of scope of the present document. 216 Below is the general procedure for this scenario: 218 1. The user activates router functionality for a LAN on the UE. 220 2. The UE checks to make sure the 3GPP interface is active and has 221 an IPv6 address. If the interface does not have an IPv6 address, 222 an attempt will be made to acquire one, or else the procedure 223 will terminate. 225 3. In this example, the UE finds the 3GPP interface has the IPv6 226 address 2001:db8:ac10:f002:1234:4567:0:9 assigned and active. 228 4. The UE moves the address 2001:db8:ac10:f002:1234:4567:0:9 as an 229 anycast /64 from the 3GPP interface to the LAN interface and 230 begins announcing the prefix 2001:db8:ac10:f002::/64 via RA to 231 the LAN. The 3GPP interface maintains the same IPv6 anycast 232 address with a /128. For this example, the LAN has 233 2001:db8:ac10:f002:1234:4567:0:9/64 and the 3GPP radio interface 234 has 2001:db8:ac10:f002:1234:4567:0:9/128. 236 5. The UE directly processes all packets destined to itself at 237 2001:db8:ac10:f002:1234:4567:0:9. 239 6. 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 a /128 and no other systems on the 3GPP radio 242 point-to-point link may use the global /64. 244 4. Security Considerations 246 tbd 248 5. IANA Considerations 250 This document does not require any action from IANA. 252 6. Acknowledgments 253 Many thanks for review and discussion from Dave Thaler, Sylvain 254 Decremps, Mark Smith, Dmitry Anipko, Masanobu Kawashima, Teemu 255 Savolainen, Mikael Abrahamsson, Eric Vyncke, Alexandru Petrescu, 256 Jouni Korhonen, Lorenzo Colitti, Julien Laganier and Owen DeLong. 258 7. Informative References 260 [RFC1981] McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery 261 for IP version 6", RFC 1981, August 1996. 263 [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic 264 Host Configuration Protocol (DHCP) version 6", RFC 3633, 265 December 2003. 267 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 268 Architecture", RFC 4291, February 2006. 270 [RFC4389] Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery 271 Proxies (ND Proxy)", RFC 4389, April 2006. 273 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 274 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 275 September 2007. 277 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 278 Address Autoconfiguration", RFC 4862, September 2007. 280 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy 281 Extensions for Stateless Address Autoconfiguration in 282 IPv6", RFC 4941, September 2007. 284 Authors' Addresses 286 Cameron Byrne 287 T-Mobile USA 288 Bellevue, Washington, USA 289 EMail: Cameron.Byrne@T-Mobile.com 291 Dan Drown 292 Email: Dan@Drown.org 294 Ales Vizdal 295 Deutsche Telekom AG 296 Tomickova 2144/1 297 Prague, 149 00 298 Czech Republic 299 EMail: Ales.Vizdal@T-Mobile.cz