rfc3314.txt

来自「RFC 的详细文档！」· 文本 代码 · 共 1,292 行 · 第 1/4 页

Network Working Group                                  M. Wasserman, Ed.
Request for Comments: 3314                                    Wind River
Category: Informational                                   September 2002


                      Recommendations for IPv6 in
         Third Generation Partnership Project (3GPP) Standards

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document contains recommendations from the Internet Engineering
   Task Force (IETF) IPv6 Working Group to the Third Generation
   Partnership Project (3GPP) community regarding the use of IPv6 in the
   3GPP standards.  Specifically, this document recommends that the 3GPP
   specify that multiple prefixes may be assigned to each primary PDP
   context, require that a given prefix must not be assigned to more
   than one primary PDP context, and allow 3GPP nodes to use multiple
   identifiers within those prefixes, including randomly generated
   identifiers.

   The IPv6 Working Group supports the use of IPv6 within 3GPP and
   offers these recommendations in a spirit of open cooperation between
   the IPv6 Working Group and the 3GPP community.  Since the original
   publication of this document as an Internet-Draft, the 3GPP has
   adopted the primary recommendations of this document.

Conventions Used In This Document

   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 BCP 14, RFC 2119
   [KEYWORD].









Wasserman                    Informational                      [Page 1]

RFC 3314       Recommendations for IPv6 in 3GPP Standards September 2002


Table of Contents

   1       Introduction.............................................  2
   1.1     What is the 3GPP?........................................  3
   1.2     What is the IETF?........................................  4
   1.3     Terminology..............................................  4
   1.3.1   3GPP Terminology.........................................  4
   1.3.2   IETF Terminology.........................................  5
   1.4     Overview of the IPv6 Addressing Architecture.............  6
   1.5     An IP-Centric View of the 3GPP System....................  7
   1.5.1   Overview of the UMTS Architecture........................  7
   1.5.2   The PDP Context.......................................... 10
   1.5.3   IPv6 Address Autoconfiguration in GPRS................... 11
   2       Recommendations to the 3GPP.............................. 13
   2.1     Limitations of 3GPP Address Assignment................... 13
   2.2     Advertising Multiple Prefixes............................ 14
   2.3     Assigning a Prefix to Only One Primary PDP Context....... 14
   2.3.1   Is a /64 per PDP Context Too Much?....................... 15
   2.3.2   Prefix Information in the SGSN........................... 16
   2.4     Multiple Identifiers per PDP Context..................... 16
   3       Additional IPv6 Work Items............................... 16
   4       Security Considerations.................................. 17
   Appendix A:  Analysis of Findings................................ 18
   Address Assignment Solutions..................................... 18
   References....................................................... 19
   Authors and Acknowledgements..................................... 22
   Editor's Address................................................. 22
   Full Copyright Statement......................................... 23

1. Introduction

   In May 2001, the IPv6 Working Group (WG) held an interim meeting in
   Redmond, WA to discuss the use of IPv6 within the 3GPP standards.
   The first day of the meeting was a joint discussion with 3GPP, during
   which an architectural overview of 3GPP's usage of IPv6 was
   presented, and there was much discussion regarding particular aspects
   of IPv6 usage within 3GPP.  At that meeting, a decision was made to
   form a design team to write a document offering advice from the IPv6
   WG to the 3GPP community, regarding their use of IPv6.  This document
   is the result of that effort.

   This document offers recommendations to the 3GPP community from the
   IETF IPv6 Working Group.  It is organized into three main sections:

      1. An introduction (this section) that provides background
         information regarding the IETF IPv6 WG and the 3GPP and
         includes a high-level overview of the technologies discussed in
         this document.



Wasserman                    Informational                      [Page 2]

RFC 3314       Recommendations for IPv6 in 3GPP Standards September 2002


      2. Recommendations from the IPv6 WG to the 3GPP community.  These
         can be found in section 2.

      3. Further work items that should be considered by the IPv6 WG.
         These items are discussed in section 3.

   It is the purpose of this document to provide advice from the IPv6
   Working Group to the 3GPP community.  We have limited the contents of
   this document to items that are directly related to the use of IPv6
   within 3GPP.  This document defines no standards, and it is not a
   definitive source of information regarding IPv6 or 3GPP.  We have not
   chosen to explore 3GPP-related issues with other IETF protocols
   (i.e., SIP, IPv4, etc.), as they are outside the scope of the IPv6
   Working Group.

   The IPv6 Working Group fully supports the use of IPv6 within 3GPP,
   and we encourage 3GPP implementers and operators to participate in
   the IETF process.  We are offering these suggestions in a spirit of
   open cooperation between the IPv6 Working Group and the 3GPP
   community, and we hope that our ongoing cooperation will help to
   strengthen both sets of standards.

   The 3GPP address allocation information in this document is based on
   the 3GPP document TS 23.060 version 4.1.0 [OLD-TS23060].  At the 3GPP
   plenary meeting TSG #15 in March 2002, the 3GPP adopted the two
   primary recommendations contained in this document, allocating a
   unique prefix to each primary PDP context when IPv6 stateless address
   autoconfiguration is used, and allowing the terminals to use multiple
   interface identifiers.  These changes were retroactively applied from
   3GPP release 99 onwards, in TS23.060 versions 3.11.0, 4.4.0 and 5.1.0
   [NEW-TS23060].

1.1 What is the 3GPP?

   The Third Generation Partnership Project (3GPP) is a global
   standardization partnership founded in late 1998.  Its Organizational
   Partners have agreed to co-operate in the production of technical
   specifications for a Third Generation Mobile System, based on the
   evolved GSM core networks.

   The 3GPP Organizational Partners consist of several different
   standardization organizations: ETSI from Europe, Standards Committee
   T1 Telecommunications (T1) in the USA, China Wireless
   Telecommunication Standard Group (CWTS), Korean Telecommunications
   Technology Association (TTA), the Association of Radio Industries and
   Businesses (ARIB), and the Telecommunication Technology
   Committee(TTC) in Japan.




Wasserman                    Informational                      [Page 3]

RFC 3314       Recommendations for IPv6 in 3GPP Standards September 2002


   The work is coordinated by a Project Co-ordination Group (PCG), and
   structured into Technical Specification Groups (TSGs).  There are
   five TSGs: Core Network (TSG CN), Radio Access Networks (TSG RAN),
   Services and System Aspects (TSG SA), GSM/EDGE Radio Access Network
   (GERAN), and the Terminals (TSG T).  The TSGs are further divided
   into Working Groups (WGs).  The technical work is done in the working
   groups, and later approved in the TSGs.

   3GPP working methods are different from IETF working methods.  The
   major difference is where the majority of the work is done.  In 3GPP,
   the work is done in face-to-face meetings, and the mailing list is
   used mainly for distributing contributions, and for handling
   documents that were not handled in the meeting, due to lack of time.
   Decisions are usually made by consensus, though voting does exist.
   However, it is rather rare to vote.  3GPP documents are public and
   can be accessed via the 3GPP web site [3GPP-URL].

1.2 What is the IETF?

   The Internet Engineering Task Force (IETF) is a large, open,
   international community of network designers, operators, vendors, and
   researchers, concerned with the evolution of the Internet
   architecture and the smooth operation of the Internet.  The IETF is
   also the primary standards body developing Internet protocols and
   standards.  It is open to any interested individual.  More
   information about the IETF can be found at the IETF web site [IETF-
   URL].

   The actual technical work of the IETF is done in working groups,
   organized by topic into several areas (e.g., routing, transport,
   security, etc.).  The IPv6 Working Group is chartered within the
   Internet area of the IETF.  Much of the work is handled via mailing
   lists, and the IETF holds meetings three times per year.

1.3 Terminology

   This section defines the 3GPP and IETF terminology used in this
   document.  The 3GPP terms and their meanings have been taken from
   [TR21905].

1.3.1   3GPP Terminology

   APN          Access Point Name.  The APN is a logical name referring
                to a GGSN and an external network.

   CS           Circuit Switched

   GERAN        GSM/EDGE Radio Access Network



Wasserman                    Informational                      [Page 4]

RFC 3314       Recommendations for IPv6 in 3GPP Standards September 2002


   GGSN         Gateway GPRS Support Node.  A router between the GPRS
                network and an external network (i.e., the Internet).

   GPRS         General Packet Radio Services

   GTP-U        General Tunneling Protocol - User Plane

   MT           Mobile Termination.  For example, a mobile phone
                handset.

   PDP          Packet Data Protocol

   PDP Context  A PDP connection between the UE and the GGSN.

   PS           Packet Switched

   SGSN         Serving GPRS Support Node

   TE           Terminal Equipment.  For example, a laptop attached
                through a 3GPP handset.

   UE           User Equipment (TE + MT + USIM).  An example would be
                a mobile handset with a USIM card inserted and a
                laptop attached.

   UMTS         Universal Mobile Telecommunications System

   USIM         Universal Subscriber Identity Module.  Typically, a
                card that is inserted into a mobile phone handset.

   UTRAN        Universal Terrestrial Radio Access Network

1.3.2   IETF Terminology

   IPv6         Internet Protocol version 6 [RFC 2460]

   NAS          Network Access Server

   NAT          Network Address Translator

   NAT-PT       Network Address Translation with Protocol Translation.
                An IPv6 transition mechanism. [NAT-PT]

   PPP          Point-to-Point Protocol [PPP]

   SIIT         Stateless IP/ICMP Transition Mechanism [SIIT]





Wasserman                    Informational                      [Page 5]

RFC 3314       Recommendations for IPv6 in 3GPP Standards September 2002


1.4 Overview of the IPv6 Addressing Architecture

   The recommendations in this document are primarily related to IPv6
   address assignment.  To fully understand the recommended changes, it
   is necessary to understand the IPv6 addressing architecture, and
   current IPv6 address assignment mechanisms.

   The IPv6 addressing architecture represents a significant evolution
   from IPv4 addressing [ADDRARCH].  It is required that all IPv6 nodes
   be able to assemble their own addresses from interface identifiers
   and prefix information.  This mechanism is called IPv6 Host
   Autoconfiguration [AUTOCONF], and it allows IPv6 nodes to configure
   themselves without the need for stateful configuration servers (i.e.,
   DHCPv6) or statically configured addresses.

   Interface identifiers can be globally unique, such as modified EUI-64
   addresses [ADDRARCH], or non-unique, such as randomly generated
   identifiers.  Hosts that have a globally unique identifier available
   may also choose to use randomly generated addresses for privacy
   [PRIVADDR] or for other reasons.  IPv6 hosts are free to generate new
   identifiers at any time, and Duplicate Address Detection (DAD) is
   used to protect against the use of duplicate identifiers on a single
   link [IPV6ND].

   A constant link-local prefix can be combined with any interface
   identifier to build an address for communication on a locally
   attached link.  IPv6 routers may advertise additional prefixes
   (site-local and/or global prefixes)[IPV6ND].  Hosts can combine
   advertised prefixes with their own interface identifiers to create
   addresses for site-local and global communication.

   IPv6 introduces architectural support for scoped unicast addressing
   [SCOPARCH].  A single interface will typically have multiple
   addresses for communication within different scopes: link-local,
   site-local and/or global [ADDRARCH].  Link-local addresses allow for
   local communication, even when an IPv6 router is not present.  Some
   IPv6 protocols (i.e., routing protocols) require the use of link-