[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-byrne-v6ops-64share) 00 01 04 05 06 07 08 09 10 RFC 7278

V6OPS Working Group                                             C. Byrne
Internet-Draft                                              T-Mobile USA
Intended Status: Informational                                  D. Drown
Expires: April 9, 2014                                         A. Vizdal
                                                     Deutsche Telekom AG
                                                         October 6, 2013


Extending an IPv6 /64 Prefix from a 3GPP Mobile Interface to a LAN link
                      draft-ietf-v6ops-64share-09


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
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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
   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



Vizdal, et al.           Expires April 9, 2014                  [Page 1]


Internet-Draft        draft-ietf-v6ops-64share-09        October 6, 2013


   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
   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
     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



























Vizdal, et al.           Expires April 9, 2014                  [Page 2]


Internet-Draft        draft-ietf-v6ops-64share-09        October 6, 2013


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.

   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.

   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.

   Section 3 describes the characteristics of each of the two example
   approaches.

1.2 Special Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

      NOTE WELL: This document is not a standard, and conformance with
      it is not required in order to claim conformance with IETF
      standards for IPv6.

   This document uses the normative keywords only for precision.

2. The Challenge of Providing IPv6 Addresses to a LAN link via a 3GPP UE

   As described in [RFC6459], 3GPP networks assign a /64 global scope
   prefix to each UE using RA.  DHCPv6 Prefix Delegation is an optional



Vizdal, et al.           Expires April 9, 2014                  [Page 3]


Internet-Draft        draft-ietf-v6ops-64share-09        October 6, 2013


   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
   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]).

   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.

   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



Vizdal, et al.           Expires April 9, 2014                  [Page 4]


Internet-Draft        draft-ietf-v6ops-64share-09        October 6, 2013


   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.

   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.

   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.

   2.  The UE checks to make sure the 3GPP interface is active and has
       an IPv6 address.  If the interface does not have an IPv6 address,
       an attempt will be made to acquire one, or else the procedure
       will terminate.

   3.  In this example, the UE finds the 3GPP interface has the IPv6



Vizdal, et al.           Expires April 9, 2014                  [Page 5]


Internet-Draft        draft-ietf-v6ops-64share-09        October 6, 2013


       address 2001:db8:ac10:f002:1234:4567:0:9 assigned and active.

   4.  The UE moves the address 2001:db8:ac10:f002:1234:4567:0:9 as a
       /64 from the 3GPP interfaces to the LAN link interface, disables
       the IPv6 SLAAC feature on the 3GPP radio interface to avoid
       address autoconfiguration, and begins announcing the prefix
       2001:db8:ac10:f002::/64 via RA to the LAN.  For this example, the
       LAN has 2001:db8:ac10:f002:1234:4567:0:9/64 and the 3GPP radio
       only has a link-local address.

   5.  The UE directly processes all packets destined to itself at
       2001:db8:ac10:f002:1234:4567:0:9.

   6.  The UE, acting as a router running NDP on the LAN, will route
       packets to and from the LAN.  IPv6 packets passing between
       interfaces will have the TTL decremented.

   7.  On the LAN link interface, there is no chance of address conflict
       since the address is defended using DAD.  The 3GPP radio
       interface only has a link-local address.

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
   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
   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.



Vizdal, et al.           Expires April 9, 2014                  [Page 6]


Internet-Draft        draft-ietf-v6ops-64share-09        October 6, 2013


   2.  The UE checks to make sure the 3GPP interface is active and has
       an IPv6 address.  If the interface does not have an IPv6 address,
       an attempt will be made to acquire one, or else the procedure
       will terminate.

   3.  In this example, the UE finds the 3GPP interface has the IPv6
       address 2001:db8:ac10:f002:1234:4567:0:9 assigned and active.

   4.  The UE moves the address 2001:db8:ac10:f002:1234:4567:0:9 as an
       anycast /64 from the 3GPP interface to the LAN interface and
       begins announcing the prefix 2001:db8:ac10:f002::/64 via RA to
       the LAN.  The 3GPP interface maintains the same IPv6 anycast
       address with a /128.  For this example, the LAN has
       2001:db8:ac10:f002:1234:4567:0:9/64 and the 3GPP radio interface
       has 2001:db8:ac10:f002:1234:4567:0:9/128.

   5.  The UE directly processes all packets destined to itself at
       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.

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.

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



Vizdal, et al.           Expires April 9, 2014                  [Page 7]


Internet-Draft        draft-ietf-v6ops-64share-09        October 6, 2013


              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3633]  Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
              Host Configuration Protocol (DHCP) version 6", RFC 3633,
              December 2003.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, February 2006.

   [RFC4389]  Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery
              Proxies (ND Proxy)", RFC 4389, April 2006.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              September 2007.

   [RFC4862]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862, September 2007.

   [RFC4941]  Narten, T., Draves, R., and S. Krishnan, "Privacy
              Extensions for Stateless Address Autoconfiguration in
              IPv6", RFC 4941, September 2007.

   [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.

Authors' Addresses

   Cameron Byrne
   T-Mobile USA
   Bellevue, Washington, USA
   EMail: Cameron.Byrne@T-Mobile.com

   Dan Drown
   Email: Dan@Drown.org

   Ales Vizdal
   Deutsche Telekom AG
   Tomickova 2144/1
   Prague, 149 00
   Czech Republic



Vizdal, et al.           Expires April 9, 2014                  [Page 8]


Internet-Draft        draft-ietf-v6ops-64share-09        October 6, 2013


   EMail: Ales.Vizdal@T-Mobile.cz


















































Vizdal, et al.           Expires April 9, 2014                  [Page 9]


Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/