Internet Protocol Version 6 (IPv6) for Some Second and Third Generation Cellular Hosts
draft-ietf-ipv6-cellular-host-02
The information below is for an old version of the document that is already published as an RFC.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 3316.
|
|
|---|---|---|---|
| Authors | Gerben Kuijpers , Juha Wiljakka , Jari Arkko , Hesham Soliman , John A. Loughney | ||
| Last updated | 2015-10-14 (Latest revision 2002-05-17) | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Informational | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | (None) | |
| Document shepherd | (None) | ||
| IESG | IESG state | Became RFC 3316 (Informational) | |
| Action Holders |
(None)
|
||
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | Dr. Thomas Narten | ||
| IESG note | |||
| Send notices to | <mrw@windriver.com> |
draft-ietf-ipv6-cellular-host-02
INTERNET-DRAFT Jari Arkko
Internet Engineering Task Force Peter Hedman
Gerben Kuijpers
Hesham Soliman
Ericsson
John Loughney
Pertti Suomela
Juha Wiljakka
Nokia
Issued: May 17, 2002
Expires: November 17, 2002
IPv6 for Some Second and Third Generation Cellular Hosts
<draft-ietf-ipv6-cellular-host-02.txt>
Status of This Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC 2026.
Internet-Drafts are working documents of the Internet Engineering
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
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.'
The list of current Internet-Drafts can be accessed at
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.
Abstract
As the deployment of second and third generation cellular networks
progresses, a large number of cellular hosts are being connected to
the Internet. Standardization organizations are making IPv6
mandatory in their specifications. However, the concept of IPv6
covers many aspects and numerous specifications. In addition, the
characteristics of cellular links in terms of bandwidth, cost and
delay put special requirements on how IPv6 is used. This document
considers IPv6 for cellular hosts that attach to the General Packet
Radio Service (GPRS), or Universal Mobile Telecommunications System
(UMTS) networks. The document lists basic components of IPv6
functionality and discusses some issues relating to the use of these
components when operating in these networks.
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
Abstract.............................................................1
1 Introduction.......................................................3
1.1 Scope of this Document..........................................3
1.2 Abbreviations...................................................4
1.4 Cellular Host IPv6 Features.....................................5
2 Basic IP...........................................................5
2.1 RFC1981 - Path MTU Discovery for IP Version 6...................5
2.2 RFC2373 - IP Version 6 Addressing Architecture..................5
2.3 RFC2460 - Internet Protocol Version 6...........................6
2.4 RFC2461 - Neighbor Discovery for IPv6...........................6
2.5 RFC2462 - IPv6 Stateless Address Autoconfiguration..............7
2.6 RFC2463 - Internet Control Message Protocol for the IPv6........7
2.7 RFC2472 - IP version 6 over PPP.................................8
2.8 RFC2473 - Generic Packet Tunneling in IPv6 Specification........8
2.9 RFC2710 - Multicast Listener Discovery (MLD) for IPv6...........8
2.10 RFC2711 - IPv6 Router Alert Option.............................9
2.11 RFC2893 - Transition Mechanisms for IPv6 Hosts and Routers.....9
2.12 RFC3041 - Privacy Extensions for Address Configuration in IPv6.9
2.13 RFC3056 - Connection of IPv6 Domains via IPv4 Clouds...........9
2.14 Dynamic Host Configuration Protocol for IPv6 (DHCPv6)..........9
2.15 Default Address Selection for IPv6.............................9
2.16 DNS............................................................9
3 IP Security.......................................................10
3.1 RFC2104 - HMAC: Keyed-Hashing for Message Authentication.......10
3.2 RFC2401 - Security Architecture for the Internet Protocol......10
3.3 RFC2402 - IP Authentication Header.............................10
3.4 RFC2403 - The Use of HMAC-MD5-96 within ESP and AH.............11
3.5 RFC2404 - The Use of HMAC-SHA-96 within ESP and AH.............11
3.6 RFC2405 - The ESP DES-CBC Cipher Algorithm With Explicit IV....11
3.7 RFC2406 - IP Encapsulating Security Payload (ESP)..............11
3.8 RFC2407 - The Internet IP Security DoI for ISAKMP..............11
3.9 RFC2408 - The Internet Security Association and Key Management 11
Protocol...........................................................11
3.10 RFC2409 - The Internet Key Exchange (IKE).....................11
3.11 RFC2410 - The NULL Encryption Algorithm & its Use With IPsec..12
3.12 RFC2451 - The ESP CBC-Mode Cipher Algorithms..................12
4. Mobility.........................................................12
5. Security Considerations..........................................13
6. References.......................................................14
6.1. Normative.....................................................14
6.2. Non-Normative.................................................16
7. Acknowledgements.................................................17
8. Authors' Addresses...............................................17
Appendix A Revision History.........................................19
Appendix B Cellular Host IPv6 Addressing in the 3GPP Model..........19
Appendix C Transition Issues........................................20
Manyfolks [Page 2]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
1 Introduction
Technologies such as GPRS (General Packet Radio Service), UMTS
(Universal Mobile Telecommunications System) and CDMA2000 (Code
Division Multiple Access 2000) are making it possible for cellular
hosts to have an always-on connection to the Internet. IPv6 becomes
necessary, as it is expected that the number of such cellular hosts
will increase rapidly. Standardization organizations working with
cellular technologies have recognized this and are making IPv6
mandatory in their specifications.
Support for IPv6 and the introduction of UMTS starts with 3GPP
Release 99 networks and hosts. IPv6 is specified as the only IP
version supported in Release 5 for IP Multimedia Subsystem (IMS).
1.1 Scope of this Document
For the purposes of this document, a cellular interface is
considered to be the interface to a cellular access network based on
the following standards: 3GPP GPRS and UMTS Release 99, Release 4,
Release 5, as well as future UMTS releases. A cellular host is
considered to be a host with such a cellular interface.
This document lists IPv6 specifications and discusses some issues
relating to the use of these specifications when operating over
cellular interfaces. Such a specification is necessary in order for
the optimal use of IPv6 in a cellular environment. The description
is made from a cellular host point of view. Important considerations
are given in order to eliminate unnecessary user confusion over
configuration options, ensure interoperability and to provide an
easy reference for those implementing IPv6 in a cellular host. It is
necessary to ensure that cellular hosts are good citizens of the
Internet.
The main audience of this document are the implementers of cellular
hosts that will be used with GPRS, 3GPP UMTS Release 99, Release 4,
Release 5, or future releases of UMTS. The document provides
guidance on which parts of IPv6 to implement in such cellular hosts.
Parts of this document may also apply to other cellular link types,
but no such detailed analysis has been done yet and is a topic of
future work. This document should not be used as a definitive list
of IPv6 functionality for cellular links other than those listed
above. Future changes in 3GPP networks that require changes in host
implementations may result in updates to this document.
There are different ways to implement cellular hosts:
- The host can be a "closed 2G or 3G host" with a very compact
size and optimized applications, with no possibility to add
or download applications that can have IP communications. An
example of such a host is a very simple form of a mobile
phone.
Manyfolks [Page 3]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
- The host can be an "open 2G or 3G host" with a compact size,
but where it is possible to download applications; such as a
PDA-type of phone.
If a cellular host has additional interfaces on which IP is used,
(such as Ethernet, WLAN, Bluetooth, etc.) then there may be
additional requirements for the device, beyond what is discussed in
this document. Additionally, this document does not make any
recommendations on the functionality required on laptop computers
having a cellular interface such as a PC card, other than
recommending link specific behavior on the cellular link.
This document discusses IPv6 functionality as specified when this
draft is written. Ongoing work on IPv6 may affect what is needed
from future hosts. The reader should also be advised other relevant
work exists for various other layers. Examples of this include the
header compression work done in the IETF ROHC group, or the TCP work
in [TCPWIRELESS].
1.2 Abbreviations
2G Second Generation Mobile Telecommunications, such as GSM
and GPRS technologies.
3G Third Generation Mobile Telecommunications, such as UMTS
technology.
3GPP 3rd Generation Partnership Project. Throughout the
document, the term 3GPP (3rd Generation Partnership
Project) networks refers to architectures standardized
by 3GPP, in Second and Third Generation releases: 99, 4,
and 5, as well as future releases.
AH Authentication Header
APN Access Point Name. The APN is a logical name referring
to a GGSN and an external network.
ESP Encapsulating Security Payload
ETSI European Telecommunications Standards Institute
IMS IP Multimedia Subsystem
GGSN Gateway GPRS Support Node (a default router for 3GPP
IPv6 cellular hosts)
GPRS General Packet Radio Service
GSM Global System for Mobile Communications
IKE Internet Key Exchange
ISAKMP Internet Security Association and Key Management
Protocol
MT Mobile Terminal, for example, a mobile phone handset.
MTU Maximum Transmission Unit
PDP Packet Data Protocol
SGSN Serving GPRS Support Node
TE Terminal Equipment, for example, a laptop attached
through a 3GPP handset.
UMTS Universal Mobile Telecommunications System
WLAN Wireless Local Area Network
Manyfolks [Page 4]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
1.4 Cellular Host IPv6 Features
This specification defines IPv6 features for cellular hosts in three
groups.
Basic IP
In this group, basic parts of IPv6 are described.
IP Security
In this group, the IP Security parts, as well as, the
suitability of various security functions to different
applications in cellular hosts are discussed.
Mobility
In this group, IP layer mobility issues are discussed.
2 Basic IP
2.1 RFC1981 - Path MTU Discovery for IP Version 6
Path MTU Discovery [RFC-1981] may be used. Cellular hosts with a
link MTU larger than the minimum IPv6 link MTU (1280 octets) can use
Path MTU Discovery in order to discover the real path MTU. The
relative overhead of IPv6 headers is minimized through the use of
longer packets, thus making better use of the available bandwidth.
The IPv6 specification [RFC-2460] states in chapter 5 that "a
minimal IPv6 implementation (e.g., in a boot ROM) may simply
restrict itself to sending packets no larger than 1280 octets, and
omit implementation of Path MTU Discovery."
If Path MTU Discovery is not implemented then the sending packet
size is limited to 1280 octets (standard limit in [RFC-2460]).
However, if this is done, the cellular host must be able to receive
packets with size up to the link MTU before reassembly. This is
because the node at the other side of the link has no way of knowing
less than the MTU is accepted.
2.2 RFC2373 - IP Version 6 Addressing Architecture
The IPv6 Addressing Architecture [RFC-2373] is a mandatory part of
IPv6. Currently, this specification is being updated by
[ADDRARCHv3]; therefore, this specification may be made obsolete by
the new one, in which case the new specification must be supported.
Manyfolks [Page 5]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
2.3 RFC2460 - Internet Protocol Version 6
The Internet Protocol Version 6 is specified in [RFC-2460]. This
specification is a mandatory part of IPv6.
By definition, a cellular host acts as a host, not as a router.
Implementation requirements for a cellular router are not defined in
this document.
Consequently, the cellular host must implement all non-router packet
receive processing as described in RFC 2460. This includes the
generation of ICMPv6 error reports, and the processing of at least
the following extension headers:
- Hop-by-Hop Options header: at least the Pad1 and PadN options
- Destination Options header: at least the Pad1 and PadN options
- Routing (Type 0) header: final destination (host) processing
only
- Fragment header
- AH and ESP headers (see also a discussion on the use of IPsec
for various purposes in Section 3)
- The No Next Header value
Unrecognized options in Hop-by-Hop Options or Destination Options
extensions must be processed as described in RFC 2460.
The cellular host must follow the packet transmission rules in RFC
2460.
The cellular host must always be able to receive and reassemble
fragment headers. It will also need to be able to send a fragment
header in cases where it communicates with an IPv4 host through a
translator.
Cellular hosts should only process routing headers when they are the
final destination and return errors if the processing of the routing
header requires them to forward the packet to another node. This
will also ensure that the cellular hosts will not be inappropriately
used as relays or components in Denial-of-Service attacks. Acting as
the destination involves the following: the cellular hosts must
check the Segments Left field in the header, and proceed if it is
zero or one and the next address is one of the host's addresses. If
not, however, the host must implement error checks as specified in
section 4.4 of RFC 2460. There is no need for the host to send
Routing Headers.
2.4 RFC2461 - Neighbor Discovery for IPv6
Neighbor Discovery is described in [RFC-2461]. This specification is
a mandatory part of IPv6.
Manyfolks [Page 6]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
2.4.1 Neighbor Discovery in 3GPP Networks
In GPRS and UMTS networks, some Neighbor Discovery messages can
cause unnecessary traffic and consume valuable (limited) bandwidth.
GPRS and UMTS links resemble a point-to-point link; hence, the
host's only neighbor on the cellular link is the default router that
is already known through Router Discovery. This router is
typically not the final destination for the host's traffic.
Additionally, due to special characteristics of the cellular link,
lower layer connectivity information should make it unnecessary to
track the reachability of the router. Therefore, while the host must
support Neighbor Solicitation and Advertisement messages, their use
is not necessary and the host may choose to not initiate them.
In addition, a cellular host should not send the link layer option
on its cellular interface, and should silently ignore it when
received on the same interface.
Hosts in a UMTS network, only need to use Router Solicitations and
Router Advertisements for 3GPP IPv6 Address Autoconfiguration (see
appendix B). Neighbor Solicitations and Advertisements may be used
for Neighbor Unreachability Detection (NUD). They are not required
for 3GPP IPv6 Stateless Address Autoconfiguration, since address
duplication is not possible in this address assignment mechanism
(see section 2.5.1).
2.5 RFC2462 - IPv6 Stateless Address Autoconfiguration
IPv6 Stateless Address Autoconfiguration is defined in [RFC-2462].
This specification is a mandatory part of IPv6.
2.5.1 Stateless Address Autoconfiguration in 3GPP Networks
A cellular host in a 3GPP network must process a Router
Advertisement as stated in section 2.4.
Hosts in 3GPP networks can set DupAddrDetectTransmits equal to zero,
as each delegated prefix is unique within its scope when allocated
using the 3GPP IPv6 Stateless Address Autoconfiguration. Thus,
Duplicate Address Detection is not required on the cellular
interface. DAD messages will not be sent or received by the IPv6
cellular host on the cellular interface.
See appendix B for more details on 3GPP IPv6 Stateless Address
Autoconfiguration.
2.6 RFC2463 - Internet Control Message Protocol for the IPv6
The Internet Control Message Protocol for the IPv6 is defined [RFC-
2463]. This specification is a mandatory part of IPv6. Currently,
this work is being updated.
Manyfolks [Page 7]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
As per RFC 2463 section 2, ICMPv6 requirements must be fully
implemented by every IPv6 node. See also Section 3 for an
explanation of the use of IPsec for protecting ICMPv6
communications.
2.7 RFC2472 - IP version 6 over PPP
IPv6 over PPP [RFC-2472] must be supported for cellular hosts that
implement PPP.
2.7.1 IP version 6 over PPP in 3GPP Networks
A cellular host in a 3GPP network must support the IPv6CP interface
identifier option. This option is needed to be able to connect other
devices to the Internet using a PPP link between the cellular device
(MT) and other devices (TE, e.g. a laptop). The MT performs the PDP
Context activation based on a request from the TE. This results in
an interface identifier being suggested by the MT to the TE, using
the IPv6CP option. To avoid any duplication in link-local addresses
between the TE and the GGSN, the MT must always reject other
suggested interface identifiers by the TE. This results in the TE
always using the interface identifier suggested by the GGSN for its
link-local address.
The rejection of interface identifiers suggested by the TE is only
done for creation of link local addresses, according to 3GPP
specifications. The use of privacy addresses [RFC-3041] for site-
local and global addresses is not affected by the above procedure.
The above procedure is only concerned with assigning the interface
identifier used for forming link-local addresses, and does not
preclude TE from using other interface identifiers for addresses
with larger scopes (i.e. site-local and global).
2.8 RFC2473 - Generic Packet Tunneling in IPv6 Specification
Generic Packet Tunneling [RFC-2473] may be supported if needed for
transition mechanisms.
2.9 RFC2710 - Multicast Listener Discovery (MLD) for IPv6
Multicast Listener Discovery [RFC-2710] may be supported, if the
cellular host is supporting applications that require the use of
multicast services. There is no need for MLD if the host only
supports the well-known (hard coded in IPv6 implementations) link
local multicast addresses. MLD is not used for listening on such
addresses.
Manyfolks [Page 8]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
2.10 RFC2711 - IPv6 Router Alert Option
The Router Alert Option [RFC-2711] may be supported. Currently, this
option is needed for MLD implementations (see section 2.9) or when
RSVP [RFC-2205] is used.
2.11 RFC2893 - Transition Mechanisms for IPv6 Hosts and Routers
[RFC-2893] specifies a number of transition mechanisms for IPv6
hosts. Cellular hosts may support the dual stack mechanism mentioned
in this specification. This also includes resolving addresses from
the DNS and selecting the type of address for the correspondent host
(IPv4 vs. IPv6). Cellular hosts should not support configured or
automatic tunnels to avoid unnecessary tunneling over the air
interface, unless there are no other mechanisms available. Tunneling
can lead to poor usage of available bandwidth.
2.12 RFC3041 - Privacy Extensions for Address Configuration in IPv6
Privacy Extensions for Stateless Address Autoconfiguration [RFC-
3041] may be used. Refer to section 5 for a discussion of the
benefits of privacy extensions in a 3GPP network.
2.13 RFC3056 - Connection of IPv6 Domains via IPv4 Clouds
Connection of IPv6 domains via IPv4 clouds [RFC-3056] should not be
supported to avoid unnecessary tunneling over the air interface. For
a cellular host, this specification would mean capability to create
6to4 tunnels starting from the cellular host itself. In a cellular
environment, tunneling over the air interface should be minimized as
tunneling can lead to poor usage of available bandwidth. Hence,
intermediate 6to4 routers should carry out 6to4 tunneling, instead
of cellular hosts.
2.14 Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
The Dynamic Host Configuration Protocol for IPv6 [DHCPv6] may be
used. DHCPv6 is not required for address autoconfiguration when IPv6
stateless autoconfiguration is used. However, DHCPv6 may be useful
for other configuration needs on a cellular host.
2.15 Default Address Selection for IPv6
Default Address Selection for IPv6 [DEFADDR] is needed for cellular
hosts with more than one address.
2.16 DNS
Cellular hosts should support DNS, as described in [RFC-1034], [RFC-
1035] and [RFC-1886].
Manyfolks [Page 9]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
If DNS is used, a cellular host should perform DNS requests in the
recursive mode, to limit signaling over the air interface.
3 IP Security
IPsec [RFC-2401] is a fundamental part of IPv6, and support for AH
and ESP is described as mandatory in the specifications.
The first part of this section discusses the applicability of IP
Security and other security mechanisms for common tasks in cellular
hosts. The second part, subsections 3.1 to 3.13, lists the RFCs
related to IPsec and discusses the use of these parts of IPsec in a
cellular context.
In general, the need to use a security mechanism depends on the
intended application for it. Different security mechanisms are
useful in different contexts, and have different limitations. Some
applications require the use of TLS [RFC-2246], in some situations
IPsec is used.
It is not realistic to list all possible services here, and it is
expected that application protocol specifications have requirements
on what security services they require. Note that cellular hosts
able to download applications must be prepared to offer sufficient
security services for these applications regardless of the needs of
the initial set of applications in those hosts.
The following sections list specifications related to the IPsec
functionality, and discuss their applicability in a cellular
context. In some applications, a different set of protocols may
need a different set of protocols may need to be employed.
In particular, the below discussion is not relevant for applications
that use other security services than IPsec.
3.1 RFC2104 - HMAC: Keyed-Hashing for Message Authentication
This specification [RFC-2104] must be supported. It is referenced by
RFC 2403 that describes how IPsec protects the integrity of packets.
3.2 RFC2401 - Security Architecture for the Internet Protocol
This specification [RFC-2401] must be supported.
3.3 RFC2402 - IP Authentication Header
This specification [RFC-2402] must be supported. The IPsec WG has
discussed the role of AH in the future, and it is possible that it
will be made optional in the future versions of the IPsec protocol
set. Implementers are recommended to take this in account.
Manyfolks [Page 10]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
3.4 RFC2403 - The Use of HMAC-MD5-96 within ESP and AH
This specification [RFC-2403] must be supported.
3.5 RFC2404 - The Use of HMAC-SHA-96 within ESP and AH
This specification [RFC-2404] must be supported.
3.6 RFC2405 - The ESP DES-CBC Cipher Algorithm With Explicit IV
This specification [RFC-2405] may be supported. It is, however,
recommended that stronger algorithms than DES be used. Algorithms,
such as AES, are undergoing work in the IPsec working group.
3.7 RFC2406 - IP Encapsulating Security Payload (ESP)
This specification [RFC-2406] must be supported.
3.8 RFC2407 - The Internet IP Security DoI for ISAKMP
Automatic key management, [RFC-2408] and [RFC-2409], is not a
mandatory part of the IP Security Architecture. Note, however, that
in the cellular environment the IP addresses of a host may change
dynamically. For this reason the use of manually configured Security
Associations is not practical, as the newest host address would have
to be updated to the SA database of the peer as well.
Even so, it is not clear that all applications would use IKE for key
management. For instance, hosts may use IPsec ESP [RFC-2406] for
protecting SIP signaling in the IMS [3GPP-ACC] but provide
authentication and key management through another mechanism such as
UMTS AKA (Authentication and Key Agreement) [UMTS-AKA].
It is likely that several simplifying assumptions can be made in the
cellular environment, with respect to the mandated parts of the IP
Security DoI, ISAKMP, and IKE. Although work on such simplifications
would be useful, is not described here.
3.9 RFC2408 - The Internet Security Association and Key Management
Protocol
This specification [RFC-2408] is optional according to the IPv6
specifications, but may be necessary in some applications, as
described in Section 3.8.
3.10 RFC2409 - The Internet Key Exchange (IKE)
This specification [RFC-2409] is optional according to the IPv6
specifications, but may be necessary in some applications, as
described in Section 3.8.
Manyfolks [Page 11]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
Interactions with the ICMPv6 packets and IPsec policies may cause
unexpected behavior for IKE-based SA negotiation unless some special
handling is performed in the implementations.
The ICMPv6 protocol provides many functions, which in IPv4 were
either non-existent or provided by lower layers. For instance, IPv6
implements address resolution using an IP packet, ICMPv6 Neighbor
Solicitation message. In contrast, IPv4 uses an ARP message at a
lower layer.
The IPsec architecture has a Security Policy Database that specifies
which traffic is protected, and how. It turns out that the
specification of policies in the presence of ICMPv6 traffic is not
easy. For instance, a simple policy of protecting all traffic
between two hosts on the same network would trap even address
resolution messages, leading to a situation where IKE can't
establish a Security Association since in order to send the IKE UDP
packets one would have had to send the Neighbor Solicitation
Message, which would have required an SA.
In order to avoid this problem, Neighbor Solicitation, Neighbor
Advertisement, Router Solicitation, and Router Advertisement
messages must not lead to the use of IKE-based SA negotiation. The
Redirect message should not lead to the use of IKE-based SA
negotiation. Other ICMPv6 messages may use IKE-based SA negotiation
as is desired in the Security Policy Data Base.
Note that the above limits the usefulness of IPsec in protecting all
ICMPv6 communications. For instance, it may not be possible to
protect the ICMPv6 traffic between a cellular host and its next hop
router. (Which may be hard in any case due to the need to establish
a suitable public key infrastructure. Since roaming is allowed, this
infrastructure would have to authenticate all hosts to all routers.)
3.11 RFC2410 - The NULL Encryption Algorithm & its Use With IPsec
This specification [RFC-2410] must be supported.
3.12 RFC2451 - The ESP CBC-Mode Cipher Algorithms
This specification [RFC-2451] must be supported if encryption
algorithms other than DES are implemented, e.g.: CAST-128, RC5,
IDEA, Blowfish, 3DES.
4. Mobility
For the purposes of this document, IP mobility is not relevant. When
Mobile IPv6 specification is approved, a future update to this
document may address these issues, as there may be some effects on
IPv6 hosts due to Mobile IP. The movement of cellular hosts within
3GPP networks is handled by link layer mechanisms.
Manyfolks [Page 12]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
5. Security Considerations
This document does not specify any new protocols or functionality,
and as such, it does not introduce any new security vulnerabilities.
However, specific profiles of IPv6 functionality are proposed for
different situations, and vulnerabilities may open or close
depending on which functionality is included and what is not. There
are also aspects of the cellular environment that make certain types
of vulnerabilities more severe. The following issues are discussed:
- The suggested limitations (Section 2.3) in the processing of
routing headers limits also exposure to Denial-of-Service attacks
through cellular hosts.
- IPv6 addressing privacy [RFC3041] may be used in cellular hosts.
However, it should be noted that in the 3GPP model, the network
would assign new addresses, in most cases, to hosts in roaming
situations and typically, also when the cellular hosts activate a
PDP context. This means that 3GPP networks will already provide a
limited form of addressing privacy, and no global tracking of a
single host is possible through its address. On the other hand,
since a GGSN's coverage area is expected to be very large when
compared to currently deployed default routers (no handovers
between GGSNs are possible), a cellular host can keep an address
for a long time. Hence, IPv6 addressing privacy can be used for
additional privacy during the time the host is on and in the same
area. The privacy features can also be used to e.g. make different
transport sessions appear to come from different IP addresses.
However, it is not clear that these additional efforts confuse
potential observers any further, as they could monitor only the
network prefix part.
- The use of various security services such as IPsec or TLS in the
connection of typical applications in cellular hosts is discussed
in Chapter 3 and recommendations are given there.
- Chapter 3 also discusses under what conditions it is possible to
provide IPsec protection of e.g. ICMPv6 communications
- The airtime used by cellular hosts is expensive. In some cases,
users are billed according to the amount of data they transfer to
and from their host. It is crucial for both the network and the
users that the airtime is used correctly and no extra charges are
applied to users due to misbehaving third parties. The cellular
links also have a limited capacity, which means that they may not
necessarily be able to accommodate more traffic than what the user
selected, such as a multimedia call. Additional traffic might
interfere with the service level experienced by the user. While
Quality of Service mechanisms mitigates these problems to an
extent, it is still apparent that Denial-of-Service (DoS) aspects
may be highlighted in the cellular environment. It is possible for
Manyfolks [Page 13]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
existing DoS attacks that use for instance packet amplification to
be substantially more damaging in this environment. How these
attacks can be protected against is still an area of further
study. It is also often easy to fill the cellular link and queues
on both sides with additional or large packets.
- Within some service provider networks, it is possible to buy a
prepaid cellular subscription without presenting personal
identification. Attackers that wish to remain unidentified could
leverage this. Note that while the user hasn't been identified,
the equipment still is; the operators can follow the identity of
the device and block it from further use. The operators must have
procedures in place to take notice of third party complaints
regarding the use of their customers' devices. It may also be
necessary for the operators to have attack detection tools that
enable them to efficiently detect attacks launched from the
cellular hosts.
- Cellular devices that have local network interfaces (such as IrDA
or Bluetooth) may be used to launch attacks through them, unless
the local interfaces are secured in an appropriate manner.
Therefore, local network interfaces should have access control to
prevent others from using the cellular host as an intermediary.
6. References
6.1. Normative
[ADDRARCHv3] Hinden, R. and Deering, S. "IP Version 6 Addressing
Architecture", Work in progress.
[DEFADDR] Draves, R., "Default Address Selection for IPv6",
Work in progress.
[DHCPv6] Bound, J. et al., "Dynamic Host Configuration
Protocol for IPv6 (DHCPv6)", Work in progress.
[RFC-1981] McCann, J., Mogul, J. and Deering, S., "Path MTU
Discovery for IP version 6", RFC 1981, August 1996.
[RFC-1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC-1886] Thomson, S. and Huitema, C., "DNS Extensions to
support IP version 6, RFC 1886, December 1995.
[RFC-2104] Krawczyk, K., Bellare, M., and Canetti, R., "HMAC:
Keyed-Hashing for Message Authentication", RFC 2104,
February 1997.
Manyfolks [Page 14]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
[RFC-2246] Dierks, T. and Allen, C., "The TLS Protocol Version
1.0", RFC 2246, January 1999
[RFC-2373] Hinden, R. and Deering, S., "IP Version 6 Addressing
Architecture", RFC 2373, July 1998.
[RFC-2401] Kent, S. and Atkinson, R., "Security Architecture for
the Internet Protocol", RFC 2401, November 1998.
[RFC-2402] Kent, S. and Atkinson, R., "IP Authentication
Header", RFC 2402, November 1998.
[RFC-2403] Madson, C., and Glenn, R., "The Use of HMAC-MD5
within ESP and AH", RFC 2403, November 1998.
[RFC-2404] Madson, C., and Glenn, R., "The Use of HMAC-SHA-1
within ESP and AH", RFC 2404, November 1998.
[RFC-2405] Madson, C. and Doraswamy, N., "The ESP DES-CBC Cipher
Algorithm With Explicit IV", RFC 2405, November 1998.
[RFC-2406] Kent, S. and Atkinson, R., "IP Encapsulating Security
Protocol (ESP)", RFC 2406, November 1998.
[RFC-2407] Piper, D., "The Internet IP Security Domain of
Interpretation for ISAKMP", RFC 2407, November 1998.
[RFC-2408] Maughan, D., Schertler, M., Schneider, M., and
Turner, J., "Internet Security Association and Key
Management Protocol (ISAKMP)", RFC 2408, November
1998.
[RFC-2409] Harkins, D., and Carrel, D., "The Internet Key
Exchange (IKE)", RFC 2409, November 1998.
[RFC-2410] Glenn, R. and Kent, S., "The NULL Encryption
Algorithm and Its Use With IPsec", RFC 2410, November
1998
[RFC-2451] Pereira, R. and Adams, R., "The ESP CBC-Mode Cipher
Algorithms", RFC 2451, November 1998
[RFC-2460] Deering, S. and Hinden, R., "Internet Protocol,
Version 6 (IPv6) Specification", RFC 2460, December
1998.
[RFC-2461] Narten, T., Nordmark, E. and Simpson, W., "Neighbor
Discovery for IP Version 6 (IPv6)", RFC 2461,
December 1998.
Manyfolks [Page 15]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
[RFC-2462] Thomson, S. and Narten, T., "IPv6 Stateless Address
Autoconfiguration", RFC 2462.
[RFC-2463] Conta, A. and Deering, S., "ICMP for the Internet
Protocol Version 6 (IPv6)", RFC 2463, December 1998.
[RFC-2473] Conta, A. and Deering, S., "Generic Packet Tunneling
in IPv6 Specification", RFC 2473, December 1998.
[RFC-2710] Deering, S., Fenner, W. and Haberman, B., "Multicast
Listener Discovery (MLD) for IPv6", RFC 2710, October
1999.
[RFC-2711] Partridge, C. and Jackson, A., "IPv6 Router Alert
Option", RFC 2711, October 1999.
[RFC-2874] Crawford, M. and Huitema, C., "DNS Extensions to
Support IPv6 Address Aggregation and Renumbering",
RFC 2874, July 2000.
[RFC-3041] Narten, T. and Draves, R., "Privacy Extensions for
Stateless Address Autoconfiguration in IPv6", RFC
3041, January 2001.
6.2. Non-Normative
[3GPP-ACC] 3GPP Technical Specification 3GPP TS 33.203,
"Technical Specification Group Services and System
Aspects; 3G Security; Access security for IP-based
services (Release 5)", 3rd Generation Partnership
Project, March 2002.
[3GPP-IMS] 3rd Generation Partnership Project; Technical
Specification Group Services and System Aspects; IP
Multimedia (IM) Subsystem - Stage 2; (3G TS 23.228)
[3GPP-IPv6] 3rd Generation Partnership Project; Technical
Specification Group Services and System Aspects
"Architectural requirements" (TS 23.221)
[IPv6-3GPP] Wasserman, M (editor), "Recommendations for IPv6 in
3GPP Standards" Work in Progress.
[RFC-1034] Mockapetris, P., "Domain names - concepts and
facilities", RFC 1034, November 1987
[RFC-2529] Carpenter, B. and Jung, C., "Transmission of IPv6
over IPv4 Domains without Explicit Tunnels", RFC
2529, March 1999.
Manyfolks [Page 16]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
[RFC-2893] Gilligan, R. and Nordmark, E., "Transition Mechanisms
for IPv6 Hosts and Routers", RFC 2893, August 2000.
[RFC-3056] Carpenter, B. and Moore, K., "Connection of IPv6
domains via IPv4 clouds", RFC 3056, February 2001.
[RFC-2205] Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification. R. Braden, Ed., L. Zhang,
S. Berson, S. Herzog, S. Jamin, RFC 2205September
1997.
[TCPWIRELESS] Inamura, H. et al. "TCP over 2.5G and 3G Networks".
IETF, Work in progress.
[UMTS-AKA] 3GPP Technical Specification 3GPP TS 33.102,
"Technical Specification Group Services and System
Aspects; 3G Security; Security Architecture (Release
4)", 3rd Generation Partnership Project, December
2001.
7. Acknowledgements
The authors would like to thank Jim Bound, Brian Carpenter, Steve
Deering, Bob Hinden, Keith Moore, Thomas Narten, Erik Nordmark,
Michael Thomas, Margaret Wasserman and others at the IPv6 WG mailing
list for their comments and input.
We would also like to thank David DeCamp, Karim El Malki, Markus
Isomki, Petter Johnsen, Janne Rinne, Jonne Soininen, Vlad Stirbu
and Shabnam Sultana for their comments and input in preparation of
this document.
8. Authors' Addresses
Jari Arkko
Ericsson
02420 Jorvas
Finland
Phone: +358 40 5079256
Fax: +358 40 2993401
E-Mail: Jari.Arkko@ericsson.com
Peter Hedman
Ericsson
SE-221 83 LUND
SWEDEN
Phone: +46 46 231760
Fax: +46 46 231650
E-mail: peter.hedman@emp.ericsson.se
Manyfolks [Page 17]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
Gerben Kuijpers
Ericsson
Skanderborgvej 232
DK-8260 Viby J
DENMARK
Phone: +45 89385100
Fax: +45 89385101
E-mail: gerben.a.kuijpers@ted.ericsson.se
Hesham Soliman
Ericsson Radio Systems AB
Torshamnsgatan 23, Kista, Stockholm
SWEDEN
Phone: +46 8 4046619
Fax: +46 8 4047020
E-mail: Hesham.Soliman@era.ericsson.se
John Loughney
Nokia Research Center
Itmerenkatu 11 û 13
FIN-00180 HELSINKI
FINLAND
Phone: +358 7180 36242
Fax: +358 7180 36851
E-mail: john.loughney@nokia.com
Pertti Suomela
Nokia Mobile Phones
Sinitaival 5
FIN-33720 TAMPERE
Finland
Phone: +358 7180 40546
Fax: +358 7180 47518
E-mail: pertti.suomela@nokia.com
Juha Wiljakka
Nokia Mobile Phones
Sinitaival 5
FIN-33720 TAMPERE
Finland
Phone: +358 7180 47562
Fax: +358 7180 47518
E-mail: juha.wiljakka@nokia.com
Manyfolks [Page 18]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
Appendix A Revision History
Changes from draft-ietf-ipv6-cellular-host-01.txt:
- Additional clarification to the scope of the document.
- Additional text on Path MTU added.
- Additional explanation in section 2.5.1
- Additional text (chapter 2.3) to show that hosts need to be
able to send the fragmentation header.
- Discussion on the use of Privacy addresses added.
- Clarification on the use of DHCPv6 added.
- Additional text to clarify the use of DAD
- Removed some references to application-specific security
mechanisms in chapter 3.
- Removed the reference to MIPv6 from 2.8
- Clarified when MLD was needed in chapter 2.9
- Removed Appendix D and references to MIPv6
- Several editorial changes.
Appendix B Cellular Host IPv6 Addressing in the 3GPP Model
The appendix aims to very briefly describe the 3GPP IPv6 addressing
model for 2G (GPRS) and 3G (UMTS) cellular networks from Release 99
onwards. More information can be found from 3GPP Technical
Specification 23.060.
There are two possibilities to allocate the address for an IPv6
node: stateless and stateful autoconfiguration. The stateful address
allocation mechanism needs a DHCP server to allocate the address for
the IPv6 node. On the other hand, the stateless autoconfiguration
procedure does not need any external entity involved in the address
autoconfiguration (apart from the GGSN).
In order to support the standard IPv6 stateless address
autoconfiguration mechanism, as recommended by the IETF, the GGSN
shall assign a prefix that is unique within its scope to each
primary PDP context that uses IPv6 stateless address
autoconfiguration. This avoids the necessity to perform Duplicate
Address Detection at the network level for every address built by
the mobile host. The GGSN always provides an Interface Identifier to
the mobile host. The Mobile host uses the interface identifier
provided by the GGSN to generate its link-local address. Since the
GGSN provides the cellular host with the interface identifier, it
must ensure the uniqueness of such identifier on the link (I.e. no
collisions between its own link local address and the cellular
host's).
In addition, the GGSN will not use any of the prefixes assigned to
cellular hosts to generate any of its own addresses.
This use of the interface identifier, combined with the fact that
each PDP context is allocated a unique prefix, will eliminate the
Manyfolks [Page 19]
Internet Draft IPv6 for Some 2G and 3G Cellular Hosts May 17, 2002
need for DAD messages over the air interface, and consequently
allows an efficient use of bandwidth. Furthermore, the allocation of
a prefix to each PDP context will allow hosts to implement the
privacy extensions in RFC 3041 without the need for further DAD
messages.
Appendix C Transition Issues
IETF has specified a number of IPv4 / IPv6 transition mechanisms
[RFC-2893] to ensure smooth transition from IPv4 to IPv6 and
interoperability between IPv4 and IPv6 during the transition period.
The three main transition methods from a cellular network point of
view are dual IPv4 / IPv6 stacks, tunneling and protocol
translators, such as NAT-PT or SIIT.
It is recommended that cellular hosts have dual IPv4 / IPv6 stacks
to be able to interoperate with both IPv4 and IPv6 domains and use
both IPv6 and IPv4 applications / services. Tunneling (for example
RFC 3056 - Connection of IPv6 Domains via IPv4 Clouds) should be
carried out in the network. In addition, any protocol translation
function, such as NAT-PT, should be implemented in the network, not
in the cellular host.
The tunneling mechanism specified by [RFC-2529] is not relevant for
a cellular host. [RFC-2529] allows isolated IPv6-only hosts to
connect to an IPv6 router via an IPv4 domain. The scenario of an
IPv6-only host in an IPv4-only cellular network is considered
unlikely.
Manyfolks [Page 20]