--- 1/draft-ietf-v6ops-64share-09.txt 2014-04-01 17:14:39.357505618 -0700 +++ 2/draft-ietf-v6ops-64share-10.txt 2014-04-01 17:14:39.377506102 -0700 @@ -1,20 +1,20 @@ V6OPS Working Group C. Byrne Internet-Draft T-Mobile USA Intended Status: Informational D. Drown -Expires: April 9, 2014 A. Vizdal +Expires: October 4, 2014 A. Vizdal Deutsche Telekom AG - October 6, 2013 + April 2, 2014 Extending an IPv6 /64 Prefix from a 3GPP Mobile Interface to a LAN link - draft-ietf-v6ops-64share-09 + draft-ietf-v6ops-64share-10 Abstract This document describes requirements for extending an IPv6 /64 prefix from a User Equipment 3GPP radio interface to a LAN link as well as two implementation examples. Status of this Memo This Internet-Draft is submitted in full conformance with the @@ -27,72 +27,85 @@ Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 6, 2014. Copyright and License Notice - Copyright (c) 2013 IETF Trust and the persons identified as the + Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Special Language . . . . . . . . . . . . . . . . . . . . . . 3 2. The Challenge of Providing IPv6 Addresses to a LAN link via a - 3GPP UE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 + 3GPP UE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Requirements for Extending the 3GPP Interface /64 IPv6 Prefix to a LAN link . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Example Methods for Extending the 3GPP Interface /64 IPv6 - Prefix to a LAN link . . . . . . . . . . . . . . . . . . . . . 4 - 4.1 General Behavior for All Example Scenarios . . . . . . . . . 4 + Prefix to a LAN link . . . . . . . . . . . . . . . . . . . . . 5 + 4.1 General Behavior for All Example Scenarios . . . . . . . . . 5 4.2 Example Scenario 1: Global Address Only Assigned to LAN link . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.3 Example Scenario 2: A Single Global Address Assigned to 3GPP Radio and LAN link . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 - 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 - 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7 - 8. Informative References . . . . . . . . . . . . . . . . . . . . 7 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 + 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 + 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 8 + 8. Informative References . . . . . . . . . . . . . . . . . . . . 8 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction 3GPP mobile cellular networks such as GSM, UMTS, and LTE have architectural support for IPv6 [RFC6459] , but only 3GPP Release-10 - and onwards of the 3GPP specification supports DHCPv6 Prefix - Delegation [RFC3633] for delegating IPv6 prefixes to a single LAN - link. To facilitate the use of IPv6 in a LAN prior to the deployment - of DHCPv6 Prefix Delegation in 3GPP networks and in User Equipment - (UE), this document describes requirements and provides examples on - how the 3GPP UE radio interface assigned global /64 prefix may be - extended from the 3GPP radio interface to a LAN link. + and onwards of the 3GPP specification [TS.23401] supports DHCPv6 + Prefix Delegation [RFC3633] for delegating IPv6 prefixes to a single + LAN link. + + To facilitate the use of IPv6 in a LAN prior to the deployment of + DHCPv6 Prefix Delegation in 3GPP networks and in User Equipment (UE), + this document describes requirements and provides examples on how the + 3GPP UE radio interface assigned global /64 prefix may be extended + from the 3GPP radio interface to a LAN link. + + There are two scenarios where this might be done. The first is where + the 3GPP node sets up and manages its own LAN (e.g., an IEEE 802.11 + SSID) and provides single-homed service to hosts that connect to this + LAN. A second scenario is where the 3GPP node connects to an + existing LAN and acts as a router in order to provide redundant or + multi-homed IPv6 service. + + This document is intended to address the first scenario, and is not + applicable to the second scenario, because the operational + complexities of the second scenario are not addressed. This can be achieved by receiving the Router Advertisement (RA) [RFC4861] announced globally unique /64 IPv6 prefix from the 3GPP - radio interface and then advertising the same IPv6 prefix to the LAN - link with RA. For all of the cases in the scope of this document, - the UE may be any device that functions as an IPv6 router between the - 3GPP network and a LAN. + radio interface by the UE and then advertising the same IPv6 prefix + to the LAN link with RA. For all of the cases in the scope of this + document, the UE may be any device that functions as an IPv6 router + between the 3GPP network and a LAN. This document describes requirements for achieving IPv6 prefix extension from a 3GPP radio interface to a LAN link including two practical implementation examples: 1) The 3GPP UE only has a global scope address on the LAN link 2) The 3GPP UE maintains the same consistent 128 bit global scope IPv6 anycast address [RFC4291] on the 3GPP radio interface and the LAN link. The LAN link is configured as a /64 and the 3GPP radio interface is configured as a /128. @@ -116,92 +129,96 @@ As described in [RFC6459], 3GPP networks assign a /64 global scope prefix to each UE using RA. DHCPv6 Prefix Delegation is an optional part of 3GPP Release-10 and is not covered by any earlier releases. Neighbor Discovery Proxy (ND Proxy) [RFC4389] functionality has been suggested as an option for extending the assigned /64 from the 3GPP radio interface to the LAN link, but ND Proxy is an experimental protocol and has some limitations with loop-avoidance. DHCPv6 is the best way to delegate a prefix to a LAN link. The - methods described in this document should only be applied when + methods described in this document SHOULD only be applied when deploying DHCPv6 Prefix Delegation is not achievable in the 3GPP network and the UE. The methods described in this document are at various stages of implementation and deployment planning. The goal of this memo is to document the available methods which may be used prior to DHCPv6 deployment. 3. Requirements for Extending the 3GPP Interface /64 IPv6 Prefix to a LAN link R-1: The 3GPP network provided /64 prefix MUST be made available on the LAN link. LAN attached devices shall be able to use the 3GPP network - assigned IPv6 prefix (e.g. using SLAAC [RFC4862]). + assigned IPv6 prefix (e.g. using IPv6 Stateless Address + Autoconfiguration - SLAAC [RFC4862]). R-2: The UE MUST defend all its IPv6 addresses on the LAN link. In case a LAN attached node will e.g. autoconfigure the same global IPv6 address as used on the 3GPP interface, the UE must - fail the Duplicate Address Detection process run by the LAN node. + fail the Duplicate Address Detection (DAD) [RFC4862] process run + by the LAN node. R-3: The LAN link configuration MUST be tightly coupled with the 3GPP link state. R-4: The UE MUST decrement the TTL when passing packets between IPv6 links across the UE. 4. Example Methods for Extending the 3GPP Interface /64 IPv6 Prefix to a LAN link 4.1 General Behavior for All Example Scenarios As [RFC6459] describes, the 3GPP network assigned /64 is completely dedicated to the UE and the gateway does not consume any of the /64 addresses. The gateway routes the entire /64 to the UE and does not perform ND or Network Unreachability Detection (NUD) [RFC4861]. Communication between the UE and the gateway is only done using link- local addresses and the link is point-to-point. This allows for the UE to reliably manipulate the /64 from the 3GPP radio interface without negatively impacting the point-to-point 3GPP radio link - interface. The LAN link RA configuration must be tightly coupled - with the 3GPP link state. If the 3GPP link goes down or changes the - IPv6 prefix, that state should be reflected in the LAN link IPv6 - configuration. Just as in a standard IPv6 router, the packet TTL - will be decremented when passing packets between IPv6 links across - the UE. The UE is employing the weak host model [RFC1122]. The RA - function on the UE is exclusively run on the LAN link. + interface. The LAN link Router Advertisement (RA) configuration must + be tightly coupled with the 3GPP link state. If the 3GPP link goes + down or changes the IPv6 prefix, that state should be reflected in + the LAN link IPv6 configuration. Just as in a standard IPv6 router, + the packet TTL will be decremented when passing packets between IPv6 + links across the UE. The UE is employing the weak host model + [RFC1122]. The RA function on the UE is exclusively run on the LAN + link. The LAN link originated RA message carries a copy of the following 3GPP radio link received RA message option fields: o MTU (if not provided by the 3GPP network, the UE will provide its 3GPP link MTU size) o Prefix Information 4.2 Example Scenario 1: Global Address Only Assigned to LAN link For this case, the UE receives the RA from the 3GPP network but does - not use a global address on the 3GPP interface. The 3GPP RA /64 - prefix information is used to configure NDP on the LAN and assigns - itself an address on the LAN link. The LAN link uses RA to announce - the prefix to the LAN. The UE LAN link interface defends its LAN - IPv6 address with DAD. The UE shall not run Stateless Address - Autoconfiguration [RFC4862] to assign a global address on the 3GPP - radio interface while routing is enabled. + not use a global address on the 3GPP interface. The 3GPP interface + received RA /64 prefix information is used to configure NDP on the + LAN. The UE assigns itself an IPv6 address on the LAN link from the + 3GPP interface received RA. The LAN link uses RA to announce the + prefix to the LAN. The UE LAN link interface defends its LAN IPv6 + address with DAD. The UE shall not run SLAAC to assign a global + address on the 3GPP radio interface while routing is enabled. This method allows the UE to originate and terminate IPv6 communications as a host while acting as an IPv6 router. The movement of the IPv6 prefix from the 3GPP radio interface to the LAN link may result in long-lived data connections being terminated during the transition from a host-only mode to router-and-host mode. + Connections which are likely to be affected are ones that have been specifically bound to the 3GPP radio interface. This method is appropriate if the UE or software on the UE cannot support multiple interfaces with the same anycast IPv6 address and the UE requires global connectivity while acting as a router. Below is the general procedure for this scenario: 1. The user activates router functionality for a LAN on the UE. @@ -235,26 +252,26 @@ 4.3 Example Scenario 2: A Single Global Address Assigned to 3GPP Radio and LAN link In this method, the UE assigns itself one address from the 3GPP network RA announced /64. This one address is configured as anycast [RFC4291] on both the 3GPP radio link as a /128 and on the LAN link as a /64. This allows the UE to maintain long lived data connections since the 3GPP radio interface address does not change when the router function is activated. This method may cause complications for certain software that may not support multiple interfaces with - the same anycast IPv6 address or are sensitive to prefix length + the same anycast IPv6 address, or are sensitive to prefix length changes. This method also creates complications for ensuring uniqueness for Privacy Extensions [RFC4941]. When Privacy Extensions are in use all temporary addresses will be copied from the 3GPP radio - interface to the LAN link and the preferred and valid lifetimes will - be synchronized, such that the temporary anycast addresses on both + interface to the LAN link. The preferred and valid lifetimes will be + synchronized, such that the temporary anycast addresses on both interfaces expire simultaneously. There might also be more complex scenarios in which the prefix length is not changed and privacy extensions are supported by having the subnet span multiple interfaces, as ND Proxy does [RFC4389]. Further elaboration is out of scope of the present document. Below is the general procedure for this scenario: 1. The user activates router functionality for a LAN on the UE. @@ -279,34 +296,50 @@ 2001:db8:ac10:f002:1234:4567:0:9. 6. On the LAN interface, there is no chance of address conflict since the address is defended using DAD. The 3GPP radio interface only has a /128 and no other systems on the 3GPP radio point-to-point link may use the global /64. 5. Security Considerations Since the UE will be switched from an IPv6 host mode to an IPv6 - router-and-host mode a basic IPv6 CPE security functions [RFC6092] - shall be considered. + router-and-host mode, a basic IPv6 CPE security functions [RFC6092] + SHOULD be applied. + + Despite the use of temporary IPv6 addresses, the mobile network + provided /64 prefix is common to all the LAN attached devices + potentially concerning privacy. A nomadic device (e.g. a smartphone) + provided IPv6 prefix is not a long lived one due to re-attaches + caused by a device reload, traveling through loosely covered areas, + etc. The network will provide a new IPv6 prefix after a successful + re-attach. + + 3GPP mobile network capable CPEs (e.g. a router) are likely to keep + the mobile network data connection up for a longer time. Some mobile + networks may be re-setting the mobile network connection regularly + (e.g. every 24 hours) others may not. Privacy concerned users shall + take appropriate measures to not to keep their IPv6 prefixes long- + lived. 6. IANA Considerations This document does not require any action from IANA. 7. Acknowledgments Many thanks for review and discussion from Dave Thaler, Sylvain Decremps, Mark Smith, Dmitry Anipko, Masanobu Kawashima, Teemu Savolainen, Mikael Abrahamsson, Eric Vyncke, Alexandru Petrescu, - Jouni Korhonen, Lorenzo Colitti, Julien Laganier, Owen DeLong and - Holger Metschulat. + Jouni Korhonen, Lorenzo Colitti, Julien Laganier, Owen DeLong, Holger + Metschulat, Yaron Sheffer and Victor Kuarsingh. Special thanks to Ann + Cerveny for her language review. 8. Informative References [RFC1122] Braden, R., Ed., "Requirements for Internet Hosts - Communication Layers", STD 3, RFC 1122, October 1989. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic @@ -333,26 +366,30 @@ [RFC6092] Woodyatt, J., Ed., "Recommended Simple Security Capabilities in Customer Premises Equipment (CPE) for Providing Residential IPv6 Internet Service", RFC 6092, January 2011. [RFC6459] Korhonen, J., Ed., Soininen, J., Patil, B., Savolainen, T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation Partnership Project (3GPP) Evolved Packet System (EPS)", RFC 6459, January 2012. + [TS.23401] 3GPP, "General Packet Radio Service (GPRS) enhancements + for Evolved Universal Terrestrial Radio Access Network (E- + UTRAN) access", 3GPP TS 23.401 10.0.0, June 2010. + Authors' Addresses Cameron Byrne T-Mobile USA Bellevue, Washington, USA EMail: Cameron.Byrne@T-Mobile.com Dan Drown - Email: Dan@Drown.org + EMail: Dan@Drown.org Ales Vizdal Deutsche Telekom AG Tomickova 2144/1 Prague, 149 00 Czech Republic EMail: Ales.Vizdal@T-Mobile.cz