draft-ietf-ipv6-3gpp-recommend-01.txt   rfc3314.txt 
Internet-Draft M. Wasserman, Editor Network Working Group M. Wasserman, Ed.
Document: draft-ietf-ipv6-3gpp-recommend-01.txt Wind River Request for Comments: 3314 Wind River
Expires: October 2002 April 2002 Category: Informational September 2002
Recommendations for IPv6 in 3GPP Standards
1 Status of this Memo
This document is an Internet-Draft and is in full conformance with Recommendations for IPv6 in
all provisions of Section 10 of RFC2026 [RFC2026]. Third Generation Partnership Project (3GPP) Standards
Internet-Drafts are working documents of the Internet Engineering Status of this Memo
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six This memo provides information for the Internet community. It does
months and may be updated, replaced, or obsoleted by other not specify an Internet standard of any kind. Distribution of this
documents at any time. It is inappropriate to use Internet-Drafts memo is unlimited.
as reference material or to cite them other than as "work in
progress."
The list of current Internet-Drafts can be accessed at Copyright Notice
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
2 Abstract Copyright (C) The Internet Society (2002). All Rights Reserved.
This document contains recommendations from the Internet Abstract
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:
1. Specify that multiple prefixes may be assigned to each This document contains recommendations from the Internet Engineering
primary PDP context, Task Force (IETF) IPv6 Working Group to the Third Generation
2. Require that a given prefix must not be assigned to more Partnership Project (3GPP) community regarding the use of IPv6 in the
than one primary PDP context, and 3GPP standards. Specifically, this document recommends that the 3GPP
3. Allow 3GPP nodes to use multiple identifiers within those specify that multiple prefixes may be assigned to each primary PDP
prefixes, including randomly generated identifiers. 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 The IPv6 Working Group supports the use of IPv6 within 3GPP and
offers these recommendations in a spirit of open cooperation offers these recommendations in a spirit of open cooperation between
between the IPv6 Working Group and the 3GPP community. Since the the IPv6 Working Group and the 3GPP community. Since the original
original publication of this document as an Internet-Draft, the publication of this document as an Internet-Draft, the 3GPP has
3GPP has adopted the primary recommendations of this document. adopted the primary recommendations of this document.
3 Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
Wasserman, Editor Expires May 2002 1
Recommendations for IPv6 in 3GPP Standards April 2002
4 Conventions Used In This Document Conventions Used In This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
this document are to be interpreted as described in RFC 2119 document are to be interpreted as described in BCP 14, RFC 2119
[KEYWORD]. [KEYWORD].
5 Table of Contents Table of Contents
1 Status of this Memo.......................................1
2 Abstract..................................................1
3 Copyright Notice..........................................1
4 Conventions Used In This Document.........................2
5 Table of Contents.........................................2
6 Introduction..............................................3
6.1 What is the 3GPP?.........................................3
6.2 What is the IETF?.........................................4
6.3 Terminology...............................................4
6.3.1 3GPP Terminology..........................................5
6.3.2 IETF Terminology..........................................5
6.4 Overview of the IPv6 Addressing Architecture..............6
6.5 An IP-Centric View of the 3GPP System.....................7
6.5.1 Overview of the UMTS Architecture.........................7
6.5.2 The PDP Context...........................................9
6.5.3 IPv6 Address Autoconfiguration in GPRS...................11
7 Recommendations to the 3GPP..............................13
7.1 Limitations of 3GPP Address Assignment...................13
7.2 Advertising Multiple Prefixes............................14
7.3 Assigning a Prefix to Only One Primary PDP Context.......14
7.3.1 Is a /64 per PDP Context Too Much?.......................14
7.3.2 Prefix Information in the SGSN...........................15
7.4 Multiple Identifiers per PDP Context.....................15
8 Additional IPv6 Work Items...............................17
9 Security Considerations..................................17
10 Appendix A: Analysis of Findings........................18
10.1 Address Assignment Solutions.............................18
11 References...............................................20
12 Authors and Acknowledgements.............................22
13 Editor's Contact Information.............................22
Wasserman, Editor Expires May 2002 2 1 Introduction............................................. 2
Recommendations for IPv6 in 3GPP Standards April 2002 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
6 Introduction 1. Introduction
In May 2001, the IPv6 Working Group (WG) held an interim meeting in 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. Redmond, WA to discuss the use of IPv6 within the 3GPP standards.
An architectural overview of 3GPP was presented, and there was much The first day of the meeting was a joint discussion with 3GPP, during
discussion regarding the use of IPv6 within 3GPP. At that meeting, which an architectural overview of 3GPP's usage of IPv6 was
a decision was made to form a design team to write a document presented, and there was much discussion regarding particular aspects
offering advice from the IPv6 WG to the 3GPP community regarding of IPv6 usage within 3GPP. At that meeting, a decision was made to
their use of IPv6. This document is the result of that effort. 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 This document offers recommendations to the 3GPP community from the
IETF IPv6 Working Group. It is organized into three main sections: IETF IPv6 Working Group. It is organized into three main sections:
1. An introduction (this section) that provides background 1. An introduction (this section) that provides background
information regarding the IETF IPv6 WG and the 3GPP and information regarding the IETF IPv6 WG and the 3GPP and
includes a high-level overview of the technologies discussed includes a high-level overview of the technologies discussed in
in this document. this document.
2. Recommendations from the IPv6 WG to the 3GPP community. 2. Recommendations from the IPv6 WG to the 3GPP community. These
These can be found in section 7. can be found in section 2.
3. Further work items that should be considered by the IPv6 WG. 3. Further work items that should be considered by the IPv6 WG.
These items are discussed in section 8. These items are discussed in section 3.
It is the purpose of this document to provide advice from the IPv6 It is the purpose of this document to provide advice from the IPv6
Working Group to the 3GPP community. We have limited the contents Working Group to the 3GPP community. We have limited the contents of
of this document to items that are directly related to the use of this document to items that are directly related to the use of IPv6
IPv6 within 3GPP. This document defines no standards, and it is within 3GPP. This document defines no standards, and it is not a
not a definitive source of information regarding IPv6 or 3GPP. We definitive source of information regarding IPv6 or 3GPP. We have not
have not chosen to explore 3GPP-related issues with other IETF chosen to explore 3GPP-related issues with other IETF protocols
protocols (i.e. SIP, IPv4, etc.), as they are outside the scope of (i.e., SIP, IPv4, etc.), as they are outside the scope of the IPv6
the IPv6 Working Group. Working Group.
The IPv6 Working Group fully supports the use of IPv6 within 3GPP, The IPv6 Working Group fully supports the use of IPv6 within 3GPP,
and we encourage 3GPP implementers and operators to participate in and we encourage 3GPP implementers and operators to participate in
the IETF process. We are offering these suggestions in a spirit of the IETF process. We are offering these suggestions in a spirit of
open cooperation between the IPv6 Working Group and the 3GPP open cooperation between the IPv6 Working Group and the 3GPP
community, and we hope that our ongoing cooperation will help to community, and we hope that our ongoing cooperation will help to
strengthen both sets of standards. strengthen both sets of standards.
The 3GPP address allocation information in this document is based The 3GPP address allocation information in this document is based on
on the 3GPP document TS 23.060 version 4.1.0 [OLD-TS23060]. At the the 3GPP document TS 23.060 version 4.1.0 [OLD-TS23060]. At the 3GPP
3GPP plenary meeting TSG #15 in March 2002, the 3GPP adopted the plenary meeting TSG #15 in March 2002, the 3GPP adopted the two
two primary recommendations contained in this document, allocating primary recommendations contained in this document, allocating a
a unique prefix to each primary PDP context when IPv6 stateless unique prefix to each primary PDP context when IPv6 stateless address
address autoconfiguration is used, and to allow the terminals to autoconfiguration is used, and allowing the terminals to use multiple
use multiple interface identifiers. These changes were interface identifiers. These changes were retroactively applied from
retroactively applied from 3GPP release 99 onwards, in TS23.060 3GPP release 99 onwards, in TS23.060 versions 3.11.0, 4.4.0 and 5.1.0
versions 3.11.0, 4.4.0 and 5.1.0 [NEW-TS23060]. [NEW-TS23060].
6.1 What is the 3GPP? 1.1 What is the 3GPP?
The Third Generation Partnership Project (3GPP) is a global The Third Generation Partnership Project (3GPP) is a global
standardization partnership founded in late 1998. Its standardization partnership founded in late 1998. Its Organizational
Partners have agreed to co-operate in the production of technical
Wasserman, Editor Expires May 2002 3 specifications for a Third Generation Mobile System, based on the
Recommendations for IPv6 in 3GPP Standards April 2002 evolved GSM core networks.
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 The 3GPP Organizational Partners consist of several different
standardization organizations: ETSI from Europe, Standards standardization organizations: ETSI from Europe, Standards Committee
Committee T1 Telecommunications (T1) in the USA, China Wireless T1 Telecommunications (T1) in the USA, China Wireless
Telecommunication Standard Group (CWTS), Korean Telecommunications Telecommunication Standard Group (CWTS), Korean Telecommunications
Technology Association (TTA), the Association of Radio Industries Technology Association (TTA), the Association of Radio Industries and
and Businesses (ARIB) and the Telecommunication Technology Businesses (ARIB), and the Telecommunication Technology
Committee(TTC) in Japan. Committee(TTC) in Japan.
The work is coordinated by a Project Co-ordination Group (PCG), and The work is coordinated by a Project Co-ordination Group (PCG), and
structured into Technical Specification Groups (TSGs). There are structured into Technical Specification Groups (TSGs). There are
five TSGs: Core Network (TSG CN), Radio Access Networks (TSG RAN), five TSGs: Core Network (TSG CN), Radio Access Networks (TSG RAN),
Services and System Aspects (TSG SA), GSM/EDGE Radio Access Network Services and System Aspects (TSG SA), GSM/EDGE Radio Access Network
(GERAN), and the Terminals (TSG T). The TSGs are further divided (GERAN), and the Terminals (TSG T). The TSGs are further divided
into Working Groups (WGs). The technical work is done in the into Working Groups (WGs). The technical work is done in the working
working groups, and later approved in the TSGs. groups, and later approved in the TSGs.
3GPP working methods are different from IETF working methods. The 3GPP working methods are different from IETF working methods. The
major difference is where the major part of the work is done. In major difference is where the majority of the work is done. In 3GPP,
3GPP, the work is done in face-to-face meetings, and the mailing the work is done in face-to-face meetings, and the mailing list is
list is used mainly for distributing contributions, and for used mainly for distributing contributions, and for handling
handling documents that were not handled in the meeting due to lack documents that were not handled in the meeting, due to lack of time.
of time. Decisions are usually made by consensus, though voting Decisions are usually made by consensus, though voting does exist.
does exist. However, it is rather rare to vote. 3GPP documents are However, it is rather rare to vote. 3GPP documents are public and
public and can be accessed via the 3GPP web site [3GPP-URL]. can be accessed via the 3GPP web site [3GPP-URL].
6.2 What is the IETF? 1.2 What is the IETF?
The Internet Engineering Task Force (IETF) is a large open The Internet Engineering Task Force (IETF) is a large, open,
international community of network designers, operators, vendors, international community of network designers, operators, vendors, and
and researchers concerned with the evolution of the Internet researchers, concerned with the evolution of the Internet
architecture and the smooth operation of the Internet. The IETF is architecture and the smooth operation of the Internet. The IETF is
also the primary standards body developing Internet protocols and also the primary standards body developing Internet protocols and
standards. It is open to any interested individual. More standards. It is open to any interested individual. More
information about the IETF can be found at the IETF web site [IETF- information about the IETF can be found at the IETF web site [IETF-
URL]. URL].
The actual technical work of the IETF is done in working groups, The actual technical work of the IETF is done in working groups,
which are organized by topic into several areas (e.g., routing, organized by topic into several areas (e.g., routing, transport,
transport, security, etc.). The IPv6 Working Group is chartered security, etc.). The IPv6 Working Group is chartered within the
within the Internet area of the IETF. Much of the work is handled Internet area of the IETF. Much of the work is handled via mailing
via mailing lists, and the IETF holds meetings three times per lists, and the IETF holds meetings three times per year.
year.
6.3 Terminology 1.3 Terminology
This section defines the 3GPP and IETF terminology used in this This section defines the 3GPP and IETF terminology used in this
document. The 3GPP terms and their meanings have been taken from document. The 3GPP terms and their meanings have been taken from
[TR21905]. [TR21905].
Wasserman, Editor Expires May 2002 4 1.3.1 3GPP Terminology
Recommendations for IPv6 in 3GPP Standards April 2002
6.3.1 3GPP Terminology
APN Access Point Name. The APN is a logical name referring APN Access Point Name. The APN is a logical name referring
to a GGSN and an external network. to a GGSN and an external network.
CS Circuit Switched CS Circuit Switched
GERAN GSM/EDGE Radio Access Network GERAN GSM/EDGE Radio Access Network
GGSN Gateway GPRS Support Node. A router between the GPRS GGSN Gateway GPRS Support Node. A router between the GPRS
network and an external network (i.e. the Internet). network and an external network (i.e., the Internet).
GPRS General Packet Radio Services GPRS General Packet Radio Services
GTP-U General Tunneling Protocol - User Plane GTP-U General Tunneling Protocol - User Plane
MT Mobile Termination. For example, a mobile phone MT Mobile Termination. For example, a mobile phone
handset. handset.
PDP Packet Data Protocol PDP Packet Data Protocol
skipping to change at line 255 skipping to change at page 5, line 36
a mobile handset with a USIM card inserted and a a mobile handset with a USIM card inserted and a
laptop attached. laptop attached.
UMTS Universal Mobile Telecommunications System UMTS Universal Mobile Telecommunications System
USIM Universal Subscriber Identity Module. Typically, a USIM Universal Subscriber Identity Module. Typically, a
card that is inserted into a mobile phone handset. card that is inserted into a mobile phone handset.
UTRAN Universal Terrestrial Radio Access Network UTRAN Universal Terrestrial Radio Access Network
6.3.2 IETF Terminology 1.3.2 IETF Terminology
IPv6 Internet Protocol version 6 [RFC 2460] IPv6 Internet Protocol version 6 [RFC 2460]
NAS Network Access Server NAS Network Access Server
NAT Network Address Translator NAT Network Address Translator
NAT-PT Network Address Translation with Protocol Translation. NAT-PT Network Address Translation with Protocol Translation.
An IPv6 transition mechanism. [NAT-PT] An IPv6 transition mechanism. [NAT-PT]
PPP Point-to-Point Protocol [PPP] PPP Point-to-Point Protocol [PPP]
Wasserman, Editor Expires May 2002 5
Recommendations for IPv6 in 3GPP Standards April 2002
SIIT Stateless IP/ICMP Transition Mechanism [SIIT] SIIT Stateless IP/ICMP Transition Mechanism [SIIT]
6.4 Overview of the IPv6 Addressing Architecture 1.4 Overview of the IPv6 Addressing Architecture
The recommendations in this document are primarily related to IPv6 The recommendations in this document are primarily related to IPv6
address assignment. To fully understand the recommended changes, address assignment. To fully understand the recommended changes, it
it is necessary to understand the IPv6 addressing architecture, and is necessary to understand the IPv6 addressing architecture, and
current IPv6 address assignment mechanisms. current IPv6 address assignment mechanisms.
The IPv6 addressing architecture represents a significant evolution The IPv6 addressing architecture represents a significant evolution
from IPv4 addressing [ADDRARCH]. It is required that all IPv6 nodes from IPv4 addressing [ADDRARCH]. It is required that all IPv6 nodes
be able to assemble their own addresses from interface identifiers be able to assemble their own addresses from interface identifiers
and prefix information. This mechanism is called IPv6 Host and prefix information. This mechanism is called IPv6 Host
Autoconfiguration [AUTOCONF], and it allows IPv6 nodes to configure Autoconfiguration [AUTOCONF], and it allows IPv6 nodes to configure
themselves without the need for stateful configuration servers themselves without the need for stateful configuration servers (i.e.,
(i.e. DHCPv6) or statically configured addresses. DHCPv6) or statically configured addresses.
Interface identifiers can be globally unique, such as modified EUI- Interface identifiers can be globally unique, such as modified EUI-64
64 addresses [ADDRARCH], or non-unique, such as randomly generated addresses [ADDRARCH], or non-unique, such as randomly generated
identifiers. Hosts that have a globally unique identifier identifiers. Hosts that have a globally unique identifier available
available may also choose to use randomly generated addresses for may also choose to use randomly generated addresses for privacy
privacy [PRIVADDR] or for other reasons. IPv6 hosts are free to [PRIVADDR] or for other reasons. IPv6 hosts are free to generate new
generate new identifiers at any time, and Duplicate Address identifiers at any time, and Duplicate Address Detection (DAD) is
Detection (DAD) is used to protect against the use of duplicate used to protect against the use of duplicate identifiers on a single
identifiers on a single link [IPV6ND]. link [IPV6ND].
A constant link-local prefix can be combined with any interface A constant link-local prefix can be combined with any interface
identifier to build an address for communication on a locally identifier to build an address for communication on a locally
attached link. IPv6 routers may advertise additional prefixes attached link. IPv6 routers may advertise additional prefixes
(site-local and/or global prefixes)[IPV6ND]. Hosts can combine (site-local and/or global prefixes)[IPV6ND]. Hosts can combine
advertised prefixes with their own interface identifiers to create advertised prefixes with their own interface identifiers to create
addresses for site-local and global communication. addresses for site-local and global communication.
IPv6 introduces architectural support for scoped unicast addressing IPv6 introduces architectural support for scoped unicast addressing
[SCOPARCH]. A single interface will typically have multiple [SCOPARCH]. A single interface will typically have multiple
addresses for communication within different scopes: link-local, addresses for communication within different scopes: link-local,
site-local and/or global [ADDRARCH]. Link-local addresses allow site-local and/or global [ADDRARCH]. Link-local addresses allow for
for local communication, even when an IPv6 router is not present. local communication, even when an IPv6 router is not present. Some
Some IPv6 protocols (i.e. routing protocols) require the use of IPv6 protocols (i.e., routing protocols) require the use of link-
link-local addresses. Site-local addressing allows communication local addresses. Site-local addressing allows communication to be
to be administratively contained within a single site. Link-local administratively contained within a single site. Link-local or
or site-local connections may also survive changes to global prefix site-local connections may also survive changes to global prefix
information (e.g. site renumbering). information (e.g., site renumbering).
IPv6 explicitly associates each address with an interface. IPv6 explicitly associates each address with an interface.
Multiple-interface hosts may have interfaces on more than one link Multiple-interface hosts may have interfaces on more than one link or
or in more than one site. Links and sites are internally in more than one site. Links and sites are internally identified
identified using zone identifiers. Proper routing of non-global using zone identifiers. Proper routing of non-global traffic and
traffic and proper address selection are ensured by the IPv6 scoped proper address selection are ensured by the IPv6 scoped addressing
addressing architecture [SCOPARCH]. architecture [SCOPARCH].
IPv6 introduces the concept of privacy addresses [PRIVADDR]. These IPv6 introduces the concept of privacy addresses [PRIVADDR]. These
addresses are generated from an advertised global prefix and a addresses are generated from an advertised global prefix and a
Wasserman, Editor Expires May 2002 6
Recommendations for IPv6 in 3GPP Standards April 2002
randomly generated identifier, and are used for anonymous access to randomly generated identifier, and are used for anonymous access to
Internet services. Applications control the generation of privacy Internet services. Applications control the generation of privacy
addresses, and new addresses can be generated at any time. addresses, and new addresses can be generated at any time.
The IPv6 site renumbering specification [SITEREN] relies upon the The IPv6 site renumbering specification [SITEREN] relies upon the
fact that IPv6 nodes will generate new addresses when new prefixes fact that IPv6 nodes will generate new addresses when new prefixes
are advertised on the link, and that they will deprecate addresses are advertised on the link, and that they will deprecate addresses
that use deprecated prefixes. that use deprecated prefixes.
In the future, additional IPv6 specifications may rely upon the In the future, additional IPv6 specifications may rely upon the
ability of IPv6 nodes to use multiple prefixes and/or multiple ability of IPv6 nodes to use multiple prefixes and/or multiple
identifiers to dynamically create new addresses. identifiers to dynamically create new addresses.
6.5 An IP-Centric View of the 3GPP System 1.5 An IP-Centric View of the 3GPP System
The 3GPP specifications define a Third Generation Mobile System. The 3GPP specifications define a Third Generation Mobile System. An
An overview of the packet switched (PS) domain of the 3GPP Release overview of the packet switched (PS) domain of the 3GPP Release 99
99 system is described in the following sections. The authors hope system is described in the following sections. The authors hope that
that this description is sufficient for the reader who is this description is sufficient for the reader who is unfamiliar with
unfamiliar with the UMTS packet switched service to understand how the UMTS packet switched service, to understand how the UMTS system
the UMTS system works, and how IPv6 is currently defined to be used works, and how IPv6 is currently defined to be used within it.
within it.
6.5.1 Overview of the UMTS Architecture 1.5.1 Overview of the UMTS Architecture
The UMTS architecture can be divided into two main domains -- the The UMTS architecture can be divided into two main domains -- the
packet switched (PS) domain, and the circuit switched (CS) domain. packet switched (PS) domain, and the circuit switched (CS) domain.
In this document, we will concentrate on the PS domain, or General In this document, we will concentrate on the PS domain, or General
Packet Radio Services (GPRS). Packet Radio Services (GPRS).
------ ------
| TE | | TE |
------ ------
| |
+R +R
| |
------ Uu ----------- Iu ----------- Gn ----------- Gi ------ Uu ----------- Iu ----------- Gn ----------- Gi
| MT |--+--| UTRAN |--+--| SGSN |--+--| GGSN |--+-- | MT |--+--| UTRAN |--+--| SGSN |--+--| GGSN |--+--
------ ----------- ----------- ----------- ------ ----------- ----------- -----------
(UE) (UE)
Figure 1: Simplified GPRS Architecture Figure 1: Simplified GPRS Architecture
Wasserman, Editor Expires May 2002 7
Recommendations for IPv6 in 3GPP Standards April 2002
------ ------
| | | |
| App |- - - - - - - - - - - - - - - - - - - - - - - - -(to app peer) | App |- - - - - - - - - - - - - - - - - - - - - - - - -(to app peer)
| | | |
|------| ------------- |------| -------------
| IP |- - - - - - - - - - - - - - - - - - - - - - -| IP |-> | IP |- - - - - - - - - - - - - - - - - - - - - - -| IP |->
| v4/6 | | v4/6 | | v4/6 | | v4/6 |
|------| ------------- ------------- |------ | |------| ------------- ------------- |------ |
| | | \ Relay / | | \ Relay / | | | | | | | \ Relay / | | \ Relay / | | | |
| | | \ / | | \ / | | | | | | | \ / | | \ / | | | |
skipping to change at line 400 skipping to change at page 8, line 30
| RLC |- - -| RLC | IP |- - -| IP | IP |- - -| IP | | | RLC |- - -| RLC | IP |- - -| IP | IP |- - -| IP | |
| | | | v4/6 | | v4/6 | v4/6 | |v4/6 | | | | | | v4/6 | | v4/6 | v4/6 | |v4/6 | |
|------| |------|------| |------|------| |------|------| |------| |------|------| |------|------| |------|------|
| MAC | | MAC | AAL5 |- - -| AAL5 | L2 |- - -| L2 | L2 | | MAC | | MAC | AAL5 |- - -| AAL5 | L2 |- - -| L2 | L2 |
|------| |------|------| |------|------| |------|------| |------| |------|------| |------|------| |------|------|
| L1 |- - -| L1 | ATM |- - -| ATM | L1 |- - -| L1 | L1 | | L1 |- - -| L1 | ATM |- - -| ATM | L1 |- - -| L1 | L1 |
------ ------------- ------------- ------------- ------ ------------- ------------- -------------
UE UTRAN SGSN GGSN UE UTRAN SGSN GGSN
(handset) (handset)
Figure 2: GPRS Protocol Stacks
Figure 2: GPRS Protocol Stacks
------ ------
| | | |
| App. |- - - - - - - - - - - - - - - - - - - - - - (to app peer) | App. |- - - - - - - - - - - - - - - - - - - - - - (to app peer)
| | | |
|------| |------|
| | | |
| IP |- - - - - - - - - - - - - - - - - - - - - - (to GGSN) | IP |- - - - - - - - - - - - - - - - - - - - - - (to GGSN)
| v4/6 | | v4/6 |
| | | | | | | |
|------| |-------------| |------| |-------------|
skipping to change at line 429 skipping to change at page 9, line 31
| | | |------| | | | |------|
| | | | MAC | | | | | MAC |
|------| |------|------| |------| |------|------|
| L1a |- - -| L1a | L1b |- - - (to UTRAN) | L1a |- - -| L1a | L1b |- - - (to UTRAN)
------ ------------- ------ -------------
TE MT TE MT
(laptop) (handset) (laptop) (handset)
Figure 3: Laptop Attached to 3GPP Handset Figure 3: Laptop Attached to 3GPP Handset
Wasserman, Editor Expires May 2002 8 The GPRS core network elements, shown in Figures 1 and 2, are the
Recommendations for IPv6 in 3GPP Standards April 2002 User Equipment (UE), Serving GPRS Support Node (SGSN), and Gateway
The GPRS core network elements shown in Figures 1 and 2 are the
User Equipment (UE), Serving GPRS Support Node (SGSN) and Gateway
GPRS Support Node (GGSN). The UTRAN comprises Radio Access Network GPRS Support Node (GGSN). The UTRAN comprises Radio Access Network
Controllers (RNC) and the UTRAN base stations. Controllers (RNC) and the UTRAN base stations.
GGSN A specialized router that functions as the gateway between the GGSN: A specialized router that functions as the gateway between the
GPRS network and the external networks, e.g. Internet. It also GPRS network and the external networks, e.g., Internet. It
gathers charging information about the connections. In many also gathers charging information about the connections. In
ways the GGSN is similar to a Network Access Server (NAS). many ways, the GGSN is similar to a Network Access Server
(NAS).
SGSN The SGSN's main functions include authentication, SGSN: The SGSN's main functions include authentication,
authorization, mobility management, and collection of billing authorization, mobility management, and collection of billing
information. The SGSN is connected to the SS7 network and information. The SGSN is connected to the SS7 network and
through that to the Home Location Register (HLR), so that it through that, to the Home Location Register (HLR), so that it
can perform user profile handling, authentication, and can perform user profile handling, authentication, and
authorization. authorization.
GTP-U is a simple tunnelling protocol running over UDP/IP GTP-U: A simple tunnelling protocol running over UDP/IP and used to
and used to route packets between RNC, SGSN and GGSN within the route packets between RNC, SGSN and GGSN within the same, or
same, or between different, UMTS backbone(s). A GTP-U tunnel is between different, UMTS backbone(s). A GTP-U tunnel is
identified at each end by a Tunnel Endpoint Identifier (TEID). identified at each end by a Tunnel Endpoint Identifier (TEID).
Only the most significant elements of the GPRS system are discussed Only the most significant elements of the GPRS system are discussed
in this document. More information about the GPRS system can be in this document. More information about the GPRS system can be
found in [OLD-TS23060]. found in [OLD-TS23060].
6.5.2 The PDP Context 1.5.2 The PDP Context
The most important 3GPP concept in this context is a PDP Context. A The most important 3GPP concept in this context is a PDP Context. A
PDP Context is a connection between the UE and the GGSN, over which PDP Context is a connection between the UE and the GGSN, over which
the packets are transferred. There are two kinds of PDP Contexts -- the packets are transferred. There are two kinds of PDP Contexts --
primary, and secondary. primary, and secondary.
The primary PDP Context initially defines the link to the GGSN. For The primary PDP Context initially defines the link to the GGSN. For
instance, an IP address is assigned to each primary PDP Context. In instance, an IP address is assigned to each primary PDP Context. In
addition, one or more secondary PDP Contexts can be added to a addition, one or more secondary PDP Contexts can be added to a
primary PDP Context, sharing the same IP address. These secondary primary PDP Context, sharing the same IP address. These secondary
PDP Contexts can have different Quality of Service characteristics PDP Contexts can have different Quality of Service characteristics
than the primary PDP Context. than the primary PDP Context.
Together a primary PDP Context and zero or more secondary PDP Together, a primary PDP Context and zero or more secondary PDP
Contexts define, in IETF terms, a link. GPRS links are point-to- Contexts define, in IETF terms, a link. GPRS links are point-to-
point. Once activated, all PDP contexts have equal status, meaning point. Once activated, all PDP contexts have equal status, meaning
that a primary PDP context can be deleted while keeping the link that a primary PDP context can be deleted while keeping the link
between the UE and the GGSN, as long as there are other (secondary) between the UE and the GGSN, as long as there are other (secondary)
PDP contexts active for the same IP address. PDP contexts active for the same IP address.
There are currently three PDP Types supported in GPRS -- IPv4, There are currently three PDP Types supported in GPRS -- IPv4, IPv6,
IPv6, and PPP. This document will only discuss the IPv6 PDP Type. and PPP. This document will only discuss the IPv6 PDP Type.
There are three basic actions that can be performed on a PDP
Context: PDP Context Activation, Modification, and Deactivation.
These actions are described in the following.
Wasserman, Editor Expires May 2002 9 There are three basic actions that can be performed on a PDP Context:
Recommendations for IPv6 in 3GPP Standards April 2002 PDP Context Activation, Modification, and Deactivation. These
actions are described in the following.
Activate PDP Context Activate PDP Context
Opens a new PDP Context to a GGSN. If a new primary Opens a new PDP Context to a GGSN. If a new primary PDP
PDP Context is activated, there is a new link created Context is activated, there is a new link created between a UE
between a UE and a GGSN. A UE can open multiple and a GGSN. A UE can open multiple primary PDP Contexts to one
primary PDP Contexts to one or more GGSNs. or more GGSNs.
Modify PDP Context Modify PDP Context
Changes the characteristics of a PDP Context, for Changes the characteristics of a PDP Context, for example QoS
example QoS attributes. attributes.
Deactivate PDP Context Deactivate PDP Context
Deactivates a PDP Context. If a primary PDP Context Deactivates a PDP Context. If a primary PDP Context and all
and all secondary PDP contexts associated with it are secondary PDP contexts associated with it are deactivated, a
deactivated, a link between the UE and the GGSN is link between the UE and the GGSN is removed.
removed.
The APN is a name which is logically linked to a GGSN. The APN may The APN is a name which is logically linked to a GGSN. The APN may
identify a service or an external network. The syntax of the APN identify a service or an external network. The syntax of the APN
corresponds to a fully qualified domain name. At PDP context corresponds to a fully qualified domain name. At PDP context
activation, the SGSN performs a DNS query to find out the GGSN(s) activation, the SGSN performs a DNS query to find out the GGSN(s)
serving the APN requested by the terminal. The DNS response serving the APN requested by the terminal. The DNS response contains
contains a list of GGSN addresses from which the SGSN selects one a list of GGSN addresses from which the SGSN selects one (in a
(in a round-robin fashion). round-robin fashion).
--------- -------- --------- --------
| | | GGSN | | | | GGSN |
| | LINK 1 | | | | LINK 1 | |
| -======== PDP Context A ========- - - -> ISP X | -======== PDP Context A ========- - - -> ISP X
| | | | | | | |
| | | | | | | |
| | | | | | | |
| /======= PDP Context B =======\ | | /======= PDP Context B =======\ |
| - | LINK 2 | - - - -> ISP Y | - | LINK 2 | - - - -> ISP Y
skipping to change at line 543 skipping to change at page 11, line 46
| TE | | | | | | TE | | | | |
|(laptop)| | | | - - -> ISP Z |(laptop)| | | | - - -> ISP Z
| | | | LINK 4 | | | | | | LINK 4 | |
| -====PPP====-----======== PDP Context E ========- | | -====PPP====-----======== PDP Context E ========- |
| | | | | | | | | | | |
| | | | | | | | | | | |
-------- --------- -------- -------- --------- --------
Figure 3: Correspondence of PDP Contexts to IPv6 Links Figure 3: Correspondence of PDP Contexts to IPv6 Links
Wasserman, Editor Expires May 2002 10 1.5.3 IPv6 Address Autoconfiguration in GPRS
Recommendations for IPv6 in 3GPP Standards April 2002
6.5.3 IPv6 Address Autoconfiguration in GPRS
GPRS supports static and dynamic address allocation. Two types of GPRS supports static and dynamic address allocation. Two types of
dynamic address allocation are supported -- stateless, and dynamic address allocation are supported -- stateless, and stateful.
stateful. Stateful address configuration uses an external protocol Stateful address configuration uses an external protocol to connect
to connect to a server that gives the IP address, e.g. DHCP. to a server that gives the IP address, e.g., DHCP.
The stateless IPv6 autoconfiguration works differently in GPRS than The stateless IPv6 autoconfiguration works differently in GPRS than
in Ethernet networks. GPRS nodes have no unique identifier, whereas in Ethernet networks. GPRS nodes have no unique identifier, whereas
Ethernet nodes can create an identifier from their EUI-48 address. Ethernet nodes can create an identifier from their EUI-48 address.
Because GPRS networks are similar to dialup networks, the stateless Because GPRS networks are similar to dialup networks, the stateless
address autoconfiguration in GPRS was based on PPPv6 [PPPV6]. address autoconfiguration in GPRS was based on PPPv6 [PPPV6].
3GPP address autoconfiguration has the following steps: 3GPP address autoconfiguration has the following steps:
1. The Activate PDP Context message is sent to the SGSN (PDP 1. The Activate PDP Context message is sent to the SGSN (PDP
Type=IPv6, PDP Address = 0, etc.). Type=IPv6, PDP Address = 0, etc.).
2. The SGSN sends a Create PDP Context message to the GGSN with 2. The SGSN sends a Create PDP Context message to the GGSN with
the above parameters. the above parameters.
3. GGSN chooses an interface identifier for the PDP Context and 3. GGSN chooses an interface identifier for the PDP Context and
creates the link-local address. It answers the SGSN with a creates the link-local address. It answers the SGSN with a
Create PDP Context response (PDP Address = link-local Create PDP Context response (PDP Address = link-local address).
address).
4. The SGSN sends an Activate PDP Context accept message to the 4. The SGSN sends an Activate PDP Context accept message to the UE
UE (PDP Address = link-local address). (PDP Address = link-local address).
5. The UE keeps the link-local address, and extracts the 5. The UE keeps the link-local address, and extracts the interface
interface identifier for later use. The UE may send a Router identifier for later use. The UE may send a Router
Solicitation message to the GGSN (first hop router). Solicitation message to the GGSN (first hop router).
6. After the PDP Context Activation the GGSN sends a Router 6. After the PDP Context Activation, the GGSN sends a Router
Advertisement to the UE. Advertisement to the UE.
7. The UE should be configured not to send Neighbor 7. The UE should be configured not to send a Neighbor Solicitation
Solicitation message. However, if one is sent the GGSN will message. However, if one is sent, the GGSN will silently
silently discard it. discard it.
8. The GGSN updates the SGSN with the whole IPv6 address. 8. The GGSN updates the SGSN with the whole IPv6 address.
Each connected handset or laptop will create a primary PDP context Each connected handset or laptop will create a primary PDP context
for communication on the Internet. A handset may create many for communication on the Internet. A handset may create many primary
primary and/or secondary PDP contexts throughout the life of its and/or secondary PDP contexts throughout the life of its connection
connection with a GGSN. with a GGSN.
Within 3GPP, the GGSN assigns a single 64-bit identifier to each Within 3GPP, the GGSN assigns a single 64-bit identifier to each
primary PDP context. The GGSN also advertises a single /64 prefix primary PDP context. The GGSN also advertises a single /64 prefix to
to the handset, and these two items are assembled into a single the handset, and these two items are assembled into a single IPv6
IPv6 address. Later, the GGSN modifies the PDP context entry in address. Later, the GGSN modifies the PDP context entry in the SGSN
the SGSN to include the whole IPv6 address, so that the SGSN can to include the whole IPv6 address, so that the SGSN can know the
know the single address of each 3GPP node (e.g. for billing single address of each 3GPP node (e.g., for billing purposes). This
address is also used in the GGSN to identify the PDP context
Wasserman, Editor Expires May 2002 11 associated with each packet. It is assumed that 3GPP nodes will not
Recommendations for IPv6 in 3GPP Standards April 2002 generate any addresses, except for the single identifier/prefix
combination assigned by the GGSN. DAD is not performed, as the GGSN
purposes). This address is also used in the GGSN to identify the will not assign the same address to multiple nodes.
PDP context associated with each packet. It is assumed that 3GPP
nodes will not generate any addresses, except for the single
identifier/prefix combination assigned by the GGSN. DAD is not
performed, as the GGSN will not assign the same address to multiple
nodes.
Wasserman, Editor Expires May 2002 12
Recommendations for IPv6 in 3GPP Standards April 2002
7 Recommendations to the 3GPP 2 Recommendations to the 3GPP
In the spirit of productive cooperation, the IPv6 Working Group In the spirit of productive cooperation, the IPv6 Working Group
recommends that the 3GPP consider three changes regarding the use recommends that the 3GPP consider three changes regarding the use of
of IPv6 within GPRS. Specifically, we recommend that the 3GPP IPv6 within GPRS. Specifically, we recommend that the 3GPP:
1. Specify that multiple prefixes may be assigned to each 1. Specify that multiple prefixes may be assigned to each primary
primary PDP context, PDP context,
2. Require that a given prefix must not be assigned to more 2. Require that a given prefix must not be assigned to more than
than one primary PDP context, and one primary PDP context, and
3. Allow 3GPP nodes to use multiple identifiers within those 3. Allow 3GPP nodes to use multiple identifiers within those
prefixes, including randomly generated identifiers. prefixes, including randomly generated identifiers.
Making these changes would provide several advantages for 3GPP Making these changes would provide several advantages for 3GPP
implementers and users: implementers and users:
Laptops that connect to 3GPP handsets will work without any Laptops that connect to 3GPP handsets will work without any
software changes. Their implementation of standard IPv6 over software changes. Their implementation of the standard IPv6 over
PPP, address assignment, and autoconfiguration mechanisms PPP, address assignment, and autoconfiguration mechanisms will
will work without any modification. This will eliminate the work without any modification. This will eliminate the need for
need for vendors and operators to build and test special 3GPP vendors and operators to build and test special 3GPP drivers and
drivers and related software. As currently specified, the related software. As currently specified, the 3GPP standards will
3GPP standards will be incompatible with laptop be incompatible with laptop implementations that generate their
implementations that generate their own identifiers for own identifiers for privacy or other purposes.
privacy or other purposes.
IPv6 software implementations could be used in 3GPP handsets IPv6 software implementations could be used in 3GPP handsets
without any modifications to the IPv6 protocol mechanisms. without any modifications to the IPv6 protocol mechanisms. This
This will make it easier to build and test 3GPP handsets. will make it easier to build and test 3GPP handsets.
Applications in 3GPP handsets will be able to take advantage Applications in 3GPP handsets will be able to take advantage of
of different types of IPv6 addresses (e.g., static addresses, different types of IPv6 addresses (e.g., static addresses,
temporary addresses for privacy, site-scoped addresses for temporary addresses for privacy, site-scoped addresses for site
site only communication, etc.) only communication, etc.)
The GPRS system will be better positioned to take advantage of The GPRS system will be better positioned to take advantage of new
new IPv6 features that are built around the current addressing IPv6 features that are built around the current addressing
architecture. architecture.
7.1 Limitations of 3GPP Address Assignment 2.1 Limitations of 3GPP Address Assignment
The current 3GPP address assignment mechanism has the following The current 3GPP address assignment mechanism has the following
limitations: limitations:
The GGSN only advertises a single /64 prefix, rather than a The GGSN only advertises a single /64 prefix, rather than a set of
set of prefixes. This will prevent the participation of 3GPP prefixes. This will prevent the participation of 3GPP nodes
nodes (e.g. handsets or 3GPP-attached laptops) in IPv6 site (e.g., handsets or 3GPP-attached laptops) in IPv6 site
renumbering, or in other mechanisms that expect IPv6 hosts to renumbering, or in other mechanisms that expect IPv6 hosts to
create addresses based on multiple advertised prefixes. create addresses based on multiple advertised prefixes.
Wasserman, Editor Expires May 2002 13 A 3GPP node is assigned a single identifier and is not allowed to
Recommendations for IPv6 in 3GPP Standards April 2002 generate additional identifiers. This will prevent the use of
privacy addresses by 3GPP nodes. This also makes 3GPP mechanisms
A 3GPP node is assigned a single identifier and is not allowed not fully compliant with the expected behavior of IPv6 nodes,
to generate additional identifiers. This will prevent the use which will result in incompatibility with popular laptop IPv6
of privacy addresses by 3GPP nodes. This also makes 3GPP stacks. For example, a laptop that uses privacy addresses for web
mechanisms not fully compliant with the expected behavior of browser connections could not currently establish a web browser
IPv6 nodes, which will result in incompatibility with popular connection over a 3GPP link.
laptop IPv6 stacks. For example, a laptop that uses privacy
addresses for web browser connections could not currently not
currently establish a web browser connection over a 3GPP link.
These limitations could be avoided by enabling the standard IPv6 These limitations could be avoided by enabling the standard IPv6
address allocation mechanisms in 3GPP nodes. The GGSN could address allocation mechanisms in 3GPP nodes. The GGSN could
advertise one or more prefixes for the local link in standard IPv6 advertise one or more prefixes for the local link in standard IPv6
Router Advertisements, and IPv6 addresses could be assembled, as Router Advertisements, and IPv6 addresses could be assembled, as
needed, by the IPv6 stack on the handset or laptop. An interface needed, by the IPv6 stack on the handset or laptop. An interface
identifier could still be assigned by the GGSN, as is currently identifier could still be assigned by the GGSN, as is currently
specified in the 3GPP standards. However, the handset or laptop specified in the 3GPP standards. However, the handset or laptop
could generate additional identifiers, as needed for privacy or could generate additional identifiers, as needed for privacy or other
other reasons. reasons.
7.2 Advertising Multiple Prefixes 2.2 Advertising Multiple Prefixes
For compliance with current and future IPv6 standards, the IPv6 WG For compliance with current and future IPv6 standards, the IPv6 WG
recommends that the 3GPP allow multiple prefixes to be advertised recommends that the 3GPP allow multiple prefixes to be advertised for
for each primary PDP context. This would have several advantages, each primary PDP context. This would have several advantages,
including: including:
3GPP nodes could participate in site renumbering and future 3GPP nodes could participate in site renumbering and future IPv6
IPv6 mechanisms that rely on the use of multiple global mechanisms that rely on the use of multiple global prefixes on a
prefixes on a single link. single link.
Site-local prefixes could be advertised on 3GPP links, if Site-local prefixes could be advertised on 3GPP links, if desired,
desired, allowing for site-constrained communication that allowing for site-constrained communication that could survive
could survive changes to global prefix information (e.g. site changes to global prefix information (e.g., site renumbering).
renumbering).
7.3 Assigning a Prefix to Only One Primary PDP Context 2.3 Assigning a Prefix to Only One Primary PDP Context
The IPv6 WG recommends that the 3GPP treat a primary PDP context, The IPv6 WG recommends that the 3GPP treat a primary PDP context,
along with its secondary PDP contexts, as a single IPv6 link, and along with its secondary PDP contexts, as a single IPv6 link, and
that the GGSN view each primary PDP context as a single subnet. that the GGSN view each primary PDP context as a single subnet.
Accordingly, a given global (or site-local) prefix should not be Accordingly, a given global (or site-local) prefix should not be
assigned to more than one PDP context. assigned to more than one PDP context.
Because multiple IPv6 hosts may attach through a 3GPP handset, the Because multiple IPv6 hosts may attach through a 3GPP handset, the
IPv6 WG recommends that one or more /64 prefixes should be assigned IPv6 WG recommends that one or more /64 prefixes should be assigned
to each primary PDP context. This will allow sufficient address to each primary PDP context. This will allow sufficient address
space for a 3GPP-attached node to allocate privacy addresses and/or space for a 3GPP-attached node to allocate privacy addresses and/or
route to a multi-link subnet [MULTLINK], and will discourage the route to a multi-link subnet [MULTLINK], and will discourage the use
use of NAT within 3GPP-attached devices. of NAT within 3GPP-attached devices.
7.3.1 Is a /64 per PDP Context Too Much?
If an operator assigns a /64 per PDP context, can we be assured
that there is enough address space for millions of mobile devices?
Wasserman, Editor Expires May 2002 14 2.3.1 Is a /64 per PDP Context Too Much?
Recommendations for IPv6 in 3GPP Standards April 2002
This question can be answered in the positive using the Host If an operator assigns a /64 per PDP context, can we be assured that
Density (HD) Ratio for address assignment efficiency [HD]. This is there is enough address space for millions of mobile devices? This
a measure of the number of addresses that can practically and question can be answered in the positive using the Host Density (HD)
easily be assigned to hosts, taking into consideration the Ratio for address assignment efficiency [HD]. This is a measure of
inefficiencies in usage resulting from the various address the number of addresses that can practically and easily be assigned
assignment processes. The HD ratio was empirically derived to hosts, taking into consideration the inefficiencies in usage
from actual telephone number and data network address assignment resulting from the various address assignment processes. The HD
cases. ratio was empirically derived from actual telephone number and data
network address assignment cases.
We can calculate the number of easily assignable /64's making the We can calculate the number of easily assignable /64's making the
following assumptions: following assumptions:
An HD ratio of 0.8 (representing the efficiency that can be An HD ratio of 0.8 (representing the efficiency that can be
achieved with no particular difficulty). achieved with no particular difficulty).
Only addresses with the 3-bit prefix 001 (the Aggregatable Only addresses with the 3-bit prefix 001 (the Aggregatable Global
Global Unicast Addresses defined by RFC 2373) are used, Unicast Addresses defined by RFC 2373) are used, resulting in 61
resulting in 61 bits of assignable address space. bits of assignable address space.
Using these assumptions, a total of 490 trillion (490x10^12) /64 Using these assumptions, a total of 490 trillion (490x10^12) /64
prefixes can be assigned. This translates into around 80,000 PDP prefixes can be assigned. This translates into around 80,000 PDP
Contexts per person on the earth today. Even assuming that a Contexts per person on the earth today. Even assuming that a
majority of these IPv6 /64 prefixes will be used by non-3GPP majority of these IPv6 /64 prefixes will be used by non-3GPP
networks, there is still clearly a sufficient number of /64 networks, there is still clearly a sufficient number of /64 prefixes.
prefixes.
Given this, it can be safely concluded that the IPv6 address space Given this, it can be safely concluded that the IPv6 address space
will not be exhausted if /64 prefixes are allocated to primary PDP will not be exhausted if /64 prefixes are allocated to primary PDP
contexts. contexts.
For more information regarding policies for IPv6 address For more information regarding policies for IPv6 address assignment,
assignment, refer to the IAB/IESG recommendations regarding address refer to the IAB/IESG recommendations regarding address assignment
assignment [IABAA], and the APNIC, ARIN and RIPE address allocation [IABAA], and the APNIC, ARIN and RIPE address allocation policy
policy [AAPOL]. [AAPOL].
7.3.2 Prefix Information in the SGSN 2.3.2 Prefix Information in the SGSN
Currently, the 3GPP standards allow only one prefix and one Currently, the 3GPP standards allow only one prefix and one
identifier for each PDP context. So, the GGSN can send a single identifier for each PDP context. So, the GGSN can send a single IPv6
IPv6 address to the SGSN, to be used for billing purposes, etc. address to the SGSN, to be used for billing purposes, etc.
Instead of using the full IPv6 address to identify a PDP context, Instead of using the full IPv6 address to identify a PDP context, the
the IPv6 WG recommends that the SGSN be informed of each prefix IPv6 WG recommends that the SGSN be informed of each prefix that is
that is currently assigned to a PDP context. By assigning a prefix currently assigned to a PDP context. By assigning a prefix to only
to only one primary PDP context, the SGSN can associate a prefix one primary PDP context, the SGSN can associate a prefix list with
list with each PDP context. each PDP context.
7.4 Multiple Identifiers per PDP Context 2.4 Multiple Identifiers per PDP Context
The IPv6 WG also recommends that the 3GPP standards be modified to The IPv6 WG also recommends that the 3GPP standards be modified to
allow multiple identifiers, including randomly generated allow multiple identifiers, including randomly generated identifiers,
identifiers, to be used within each assigned prefix. This would to be used within each assigned prefix. This would allow 3GPP nodes
allow 3GPP nodes to generate and use privacy addresses, and would to generate and use privacy addresses, and would be compatible with
be compatible with future IPv6 standards that may depend on the future IPv6 standards that may depend on the ability of IPv6 nodes to
generate new interface identifiers for communication.
Wasserman, Editor Expires May 2002 15
Recommendations for IPv6 in 3GPP Standards April 2002
ability of IPv6 nodes to generate new interface identifiers for
communication.
This is a vital change, necessary to allow standards-compliant IPv6 This is a vital change, necessary to allow standards-compliant IPv6
nodes to connect to the Internet through 3GPP handsets, without nodes to connect to the Internet through 3GPP handsets, without
modification. It is expected that most IPv6 nodes, including the modification. It is expected that most IPv6 nodes, including the
most popular laptop stacks, will generate privacy addresses. The most popular laptop stacks, will generate privacy addresses. The
current 3GPP specifications will not be compatible with those current 3GPP specifications will not be compatible with those
implementations. implementations.
Wasserman, Editor Expires May 2002 16 3 Additional IPv6 Work Items
Recommendations for IPv6 in 3GPP Standards April 2002
8 Additional IPv6 Work Items
During our work on this document, we have discovered several areas During our work on this document, we have discovered several areas
that could benefit from further informational or standards-track that could benefit from further informational or standards-track work
work within the IPv6 Working Group. within the IPv6 Working Group.
The IPv6 WG should work to define a point-to-point architecture and The IPv6 WG should work to define a point-to-point architecture and
specify how the standard IPv6 address assignment mechanisms are specify how the standard IPv6 address assignment mechanisms are
applicable to IPv6 over point-to-point links. We should also applicable to IPv6 over point-to-point links. We should also review
review and clarify the IPv6 over PPP specification [PPP] to match and clarify the IPv6 over PPP specification [PPP] to match the
the current IPv6 addressing architecture [ADDRARCH]. current IPv6 addressing architecture [ADDRARCH].
The IPv6 WG should consider publishing an "IPv6 over PDP Contexts" The IPv6 WG should consider publishing an "IPv6 over PDP Contexts"
(or similar) document. This document would be useful for (or similar) document. This document would be useful for developers
developers writing drivers for IPv6 stacks to work over 3GPP PDP writing drivers for IPv6 stacks to work over 3GPP PDP Contexts.
Contexts.
The IPv6 working group should undertake an effort to define the The IPv6 working group should undertake an effort to define the
minimal requirements for all IPv6 nodes. minimal requirements for all IPv6 nodes.
9 Security Considerations 4 Security Considerations
This document contains recommendations on the use of the IPv6 This document contains recommendations on the use of the IPv6
protocol in 3GPP standards. It does not specify a protocol, and it protocol in 3GPP standards. It does not specify a protocol, and it
introduces no new security considerations. introduces no new security considerations.
Wasserman, Editor Expires May 2002 17 Appendix A: Analysis of Findings
Recommendations for IPv6 in 3GPP Standards April 2002
10 Appendix A: Analysis of Findings
This section includes some analysis that may be useful to This section includes some analysis that may be useful to
understanding why the IPv6 working group is making the above understanding why the IPv6 working group is making the above
recommendations. It also includes some other options that were recommendations. It also includes some other options that were
explored, and the reasons why those options were less suitable than explored, and the reasons why those options were less suitable than
the recommendations outlined above. the recommendations outlined above.
10.1 Address Assignment Solutions A.1 Address Assignment Solutions
In order to allow for the configuration and use of multiple IPv6 In order to allow for the configuration and use of multiple IPv6
addresses per primary PDP Context having different interface addresses per primary PDP Context having different interface
identifiers, some modifications to the current 3GPP specifications identifiers, some modifications to the current 3GPP specifications
would be required. would be required.
The solutions to achieve this were evaluated against the following The solutions to achieve this were evaluated against the following
factors: factors:
- Scarcity and high cost of wireless spectrum - Scarcity and high cost of wireless spectrum
- Complexity of implementation and state maintenance - Complexity of implementation and state maintenance
- Stability of the relevant IETF standards - Stability of the relevant IETF standards
- Impact on current 3GPP standards - Impact on current 3GPP standards
Two solutions to allow autoconfiguration of multiple addresses on Two solutions to allow autoconfiguration of multiple addresses on the
the same primary PDP Context were considered: same primary PDP Context were considered:
1. Assign one or more entire prefixes (/64s) to a PDP Context 1. Assign one or more entire prefixes (/64s) to a PDP Context upon
upon PDP Context activation and allow the autoconfiguration PDP Context activation and allow the autoconfiguration of
of multiple addresses. multiple addresses.
a) The assignment may be performed by having the GGSN a) The assignment may be performed by having the GGSN advertise
advertise one or more /64 prefixes to the mobile one or more /64 prefixes to the mobile device.
device.
b) The assignment may be performed by building "prefix b) The assignment may be performed by building "prefix
delegation" functionality into the PDP Context delegation" functionality into the PDP Context messages or
messages or by using layer 3 mechanisms such as by using layer 3 mechanisms such as [PREFDEL]. In this way,
[PREFDEL]. In this way the prefix is not assigned to the prefix is not assigned to the link between the GGSN and
the link between the GGSN and the mobile device (as in the mobile device (as in 1a), but it is assigned to the
1a) but it is assigned to the mobile device itself. mobile device itself. Note that [PREFDEL] cannot be
Note that [PREFDEL] cannot be considered stable considered stable and has not, at this stage, been adopted
and has not at this stage been adopted by the IPv6 WG by the IPv6 WG as a WG document.
as a WG document.
2. Share the same prefix between multiple PDP Contexts
connected to the same GGSN (and APN). Given that mobile
devices may generate multiple addresses using more than one
interface identifier, this would require DAD for the newly
generated addresses over the air interface, and a proxy DAD
function which would increase the complexity and the amount
of state to be kept in the GGSN. Also, the GGSN would need
to determine when the temporary addresses are no longer in
use which would be difficult. One possible solution could be
Wasserman, Editor Expires May 2002 18
Recommendations for IPv6 in 3GPP Standards April 2002
using periodic unicast neighbor solicitations for the 2. Share the same prefix between multiple PDP Contexts connected
temporary addresses [IPV6ND]. to the same GGSN (and APN). Given that mobile devices may
generate multiple addresses using more than one interface
identifier, this would require DAD for the newly generated
addresses over the air interface, and a proxy DAD, function
which would increase the complexity and the amount of state to
be kept in the GGSN. Also, the GGSN would need to determine
when the temporary addresses are no longer in use, which would
be difficult. One possible solution could be using periodic
unicast neighbor solicitations for the temporary addresses
[IPV6ND].
Considering all the factors when evaluating the solutions, the Considering all the factors when evaluating the solutions, the
recommendation is to use Solution 1a. This solution requires the recommendation is to use Solution 1a. This solution requires the
least modification to the current 3GPP standards and maintains all least modification to the current 3GPP standards and maintains all
the advantages of the other solutions. the advantages of the other solutions.
Effectively this would mean that each APN in a GGSN would have a Effectively, this would mean that each APN in a GGSN would have a
certain number of /64 prefixes that can be handed out at PDP certain number of /64 prefixes that can be handed out at PDP context
context Activation, through Router Advertisements. Therefore, Activation, through Router Advertisements. Therefore, instead of
instead of using the full IPv6 address to identify a primary PDP using the full IPv6 address to identify a primary PDP context, the
context, the IPv6 WG recommends that the GGSN use the entire prefix IPv6 WG recommends that the GGSN use the entire prefix (together with
(together with other 3GPP specific information) and that the SGSN other 3GPP specific information) and that the SGSN be informed of the
be informed of the prefixes that are assigned to a PDP context. By prefixes that are assigned to a PDP context. By assigning a given
assigning a given prefix to only one primary PDP context, the GGSN prefix to only one primary PDP context, the GGSN and SGSN can
and SGSN can associate a prefix list with each PDP context, as associate a prefix list with each PDP context, as needed.
needed.
Note that the recommended solution does not imply or assume that Note that the recommended solution does not imply or assume that the
the mobile device is a router. The MT is expected to use the /64 mobile device is a router. The MT is expected to use the /64 for
for itself and may also use this prefix for devices attached to it. itself and may also use this prefix for devices attached to it.
However this is not necessary if each device behind the MT is However, this is not necessary if each device behind the MT is
connected to a separate primary PDP Context and therefore can use a connected to a separate primary PDP Context and therefore can use a
/64 which is not shared with other devices. The MT is also expected /64, which is not shared with other devices. The MT is also expected
to handle DAD locally for devices attached to it (e.g. laptops) to handle DAD locally for devices attached to it (e.g., laptops)
without forwarding Neighbor Solicitations over the air to the GGSN. without forwarding Neighbor Solicitations over the air to the GGSN.
Wasserman, Editor Expires May 2002 19 References
Recommendations for IPv6 in 3GPP Standards April 2002
11 References
[OLD-TS23060]
TS 23.060, "General Packet Radio Service (GPRS); Service
description; Stage 2", V4.1.0
[NEW-TS23060] [OLD-TS23060] TS 23.060, "General Packet Radio Service (GPRS);
TS 23.060 version 3.11.0 (release 99), 4.4.0 (release 4) Service description; Stage 2", V4.1.0
and 5.1.0 (release 5).
[3GPP-URL] [NEW-TS23060] TS 23.060 version 3.11.0 (release 99), 4.4.0 (release
http://www.3gpp.org 4) and 5.1.0 (release 5).
[IETF-URL] [3GPP-URL] http://www.3gpp.org
http://www.ietf.org
[RFC2026] [IETF-URL] http://www.ietf.org
S. Bradner, "The Internet Standards Process -- Revision 3",
RFC 2026, BCP9, October 1996
[KEYWORD] [RFC2026] Bradner, S., "The Internet Standards Process --
S. Bradner, "Key words for use in RFCs to Indicate Requirement Revision 3", BCP 9, RFC 2026, October 1996
Levels", RFC 2119, BCP14, March 1999.
[TR21905] [KEYWORD] Bradner, S., "Key words for use in RFCs to Indicate
3GPP TR 21.905, "Vocabulary for 3GPP Specifications", V5.0.0 Requirement Levels", BCP 14, RFC 2119, March 1999.
[IPV6] [TR21905] 3GPP TR 21.905, "Vocabulary for 3GPP Specifications",
S. Deering, R. Hinden, "Internet Protocol, Version 6 (IPv6) V5.0.0
Specification", RFC 2460, December 1998.
[NAT-PT] [IPV6] Deering, S. and R. Hinden, "Internet Protocol, Version
G. Tsirtsis, P. Shrisuresh, "Network Address Translation - 6 (IPv6) Specification", RFC 2460, December 1998.
Protocol Translation (NAT-PT)", RFC2766, February 2000.
[PPP] [NAT-PT] Tsirtsis, G. and P. Shrisuresh, "Network Address
Simpson, W., "The Point-to-Point Protocol (PPP)", STD 51, RFC Translation - Protocol Translation (NAT-PT)", RFC 2766,
1661, July 1994. February 2000.
[SIIT] [PPP] Simpson, W., "The Point-to-Point Protocol (PPP)", STD
E. Nordmark, "Stateless IP/ICMP Translation Algorithm", RFC 51, RFC 1661, July 1994.
2765, February 2000.
[ADDRARCH] [SIIT] Nordmark, N., "Stateless IP/ICMP Translation
R. Hinden, S. Deering, "IP Version 6 Addressing Architecture", Algorithm", RFC 2765, February 2000.
RFC 2373, July 1998
[IPV6ND] [ADDRARCH] Hinden, R. and S. Deering, "IP Version 6 Addressing
T. Narten, E. Nordmark, W. Simpson, "Neighbor Discovery for IP Architecture", RFC 2373, July 1998.
Version 6 (IPv6)", RFC 2461, December 1998
Wasserman, Editor Expires May 2002 20 [IPV6ND] Narten, T., Nordmark, E. and W. Simpson, "Neighbor
Recommendations for IPv6 in 3GPP Standards April 2002 Discovery for IP Version 6 (IPv6)", RFC 2461, December
1998.
[AUTOCONF] [AUTOCONF] Thomson, S. and T. Narten, "IPv6 Stateless Address
S. Thomson, T. Narten, "IPv6 Stateless Address
Autoconfiguration", RFC 2462, December 1998 Autoconfiguration", RFC 2462, December 1998
[PRIVADDR] [PRIVADDR] Narten, T. and R. Draves, "Privacy Extensions for
T. Narten, R. Draves, "Privacy Extensions for Stateless Stateless Address Autoconfiguration in IPv6", RFC 3041,
Address Autoconfiguration in IPv6", RFC 3041, January 2001 January 2001.
[IPV6ETH] [IPV6ETH] Crawford, M., "Transmission of IPv6 Packets over
M. Crawford, "Transmission of IPv6 Packets over Ethernet Ethernet Networks", RFC 2464, December 1998.
Networks", RFC 2464, December 1998
[PPPv6] [PPPv6] Haskin, D. and E. Allen, "IP Version 6 over PPP", RFC
D. Haskin, E. Allen, "IP Version 6 over PPP", RFC2472, 2472, December 1998.
December 1998.
[MULTLINK] [MULTLINK] C. Huitema, D. Thaler, "Multi-link Subnet Support in
C. Huitema, D. Thaler, "Multi-link Subnet Support in IPv6", IPv6", Work in Progress.
draft-thaler-ipngwg-multilink-subnets-01.txt, July 2001
[SITEREN] [SITEREN] C. Huitema, "IPv6 Site Renumbering", Work in Progress.
C. Huitema, "IPv6 Site Renumbering", draft-huitema-ipv6-
renumber-00.txt, July 2001
[HD] [HD] Durand, A. and C. Huitema, "The Host-Density Ratio for
C. Huitema, A. Durand, "The Host-Density Ratio for Address Address Assignment Efficiency: An update on the H
Assignment Efficiency: An update on the H ratio", draft- ratio", RFC 3194, November 2001.
durand-huitema-h-density-ratio-02.txt, August 2001
[IABAA] [IABAA] IAB, IESG, "IAB/IESG Recommendations on IPv6 Address
IAB, IESG, "IAB/IESG Recommendations on IPv6 Address
Allocations to Sites", RFC3177, September 2001. Allocations to Sites", RFC3177, September 2001.
[AAPOL] [AAPOL] APNIC, ARIN, RIPE-NCC, "IPv6 Address Allocation and
APNIC, ARIN, RIPE-NCC, "IPv6 Address Allocation and Assignment Assignment Global Policy", Work in Progress.
Global Policy". Draft of December, 22 2001, Version 2001-12-
22 [ftp://ftp.cs.duke.edu/pub/narten/global-ipv6-assign-2001-
12-22.txt]
[SCOPARCH]
S. Deering, et. al, "IPv6 Scoped Address Architecture", draft-
ietf-ipngwg-scoping-arch-02.txt, March 2001
[CELLREQ] [SCOPARCH] S. Deering, et. al., "IPv6 Scoped Address
J. Arkko, et. al, "Minimum IPv6 Functionality for a Cellular Architecture", Work in Progress.
Host", draft-manyfolks-ipv6-cellular-host-01.txt, September
2001
[PREFDEL] [CELLREQ] J. Arkko, et. al., "Minimum IPv6 Functionality for a
J. Martin, B. Haberman, "Automatic Prefix Delegation Protocol Cellular Host", Work in Progress.
for Internet Protocol Version 6 (IPv6)", draft-haberman-
ipngwg-auto-prefix-01.txt, July 2001
Wasserman, Editor Expires May 2002 21 [PREFDEL] J. Martin, B. Haberman, "Automatic Prefix Delegation
Recommendations for IPv6 in 3GPP Standards April 2002 Protocol for Internet Protocol Version 6 (IPv6)", Work
in Progress.
12 Authors and Acknowledgements Authors and Acknowledgements
This document was written by the IPv6 3GPP design team: This document was written by the IPv6 3GPP design team:
Steve Deering, Cisco Systems Steve Deering, Cisco Systems
<deering@cisco.com> EMail: deering@cisco.com
Karim El-Malki, Ericsson Radio Systems Karim El-Malki, Ericsson Radio Systems
<Karim.El-Malki@era.ericsson.se> EMail: Karim.El-Malki@era.ericsson.se
Paul Francis, Tahoe Networks Paul Francis, Tahoe Networks
<francis@tahoenetworks.com> EMail: francis@tahoenetworks.com
Bob Hinden, Nokia Bob Hinden, Nokia
<hinden@iprg.nokia.com> EMail: hinden@iprg.nokia.com
Christian Huitema, Microsoft Christian Huitema, Microsoft
<huitema@windows.microsoft.com> EMail: huitema@windows.microsoft.com
Niall Richard Murphy, Hutchison 3G Niall Richard Murphy, Hutchison 3G
<niallm@enigma.ie> EMail: niallm@enigma.ie
Markku Savela, Technical Research Centre of Finland Markku Savela, Technical Research Centre of Finland
<Markku.Savela@vtt.fi> Email: Markku.Savela@vtt.fi
Jonne Soininen, Nokia Jonne Soininen, Nokia
<Jonne.Soininen@nokia.com> EMail: Jonne.Soininen@nokia.com
Margaret Wasserman, Wind River Margaret Wasserman, Wind River
<mrw@windriver.com> EMail: mrw@windriver.com
Information was incorporated from a presentation co-authored by: Information was incorporated from a presentation co-authored by:
Juan-Antonio Ibanez, Ericsson Eurolab Juan-Antonio Ibanez, Ericsson Eurolab
13 Editor's Contact Information Editor's Address
Comments or questions regarding this document should be sent to: Comments or questions regarding this document should be sent to:
Margaret Wasserman Margaret Wasserman
Wind River Wind River
10 Tara Blvd., Suite 330 Phone: (603) 897-2067 10 Tara Blvd., Suite 330
Nashua, NH 03062 USA Email: mrw@windriver.com Nashua, NH 03062 USA
Wasserman, Editor Expires May 2002 22 Phone: (603) 897-2067
EMail: mrw@windriver.com
Full Copyright Statement
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