Internet Engineering Task Force (IETF) R. Wakikawa
Request for Comments: 5844 Toyota ITC
Category: Standards Track S. Gundavelli
ISSN: 2070-1721 Cisco
May 2010
IPv4 Support for Proxy Mobile IPv6
Abstract
This document specifies extensions to the Proxy Mobile IPv6 protocol
for adding IPv4 protocol support. The scope of IPv4 protocol support
is two-fold: 1) enable IPv4 home address mobility support to the
mobile node, and 2) allow the mobility entities in the Proxy Mobile
IPv6 domain to exchange signaling messages over an IPv4 transport
network.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc5844.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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publication of this document. Please review these documents
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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RFC 5844 IPv4 Support for Proxy Mobile IPv6 May 2010
Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Stated Assumptions . . . . . . . . . . . . . . . . . . . . 4
1.2. Relevance to Dual-Stack Mobile IPv6 . . . . . . . . . . . 5
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 6
2.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 6
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6
3. IPv4 Home Address Mobility Support . . . . . . . . . . . . . . 8
3.1. Local Mobility Anchor Considerations . . . . . . . . . . . 9
3.1.1. Extensions to Binding Cache Entry . . . . . . . . . . 9
3.1.2. Signaling Considerations . . . . . . . . . . . . . . . 10
3.1.3. Routing Considerations for the Local Mobility
Anchor . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1.4. ECN and Payload Fragmentation Considerations . . . . . 16
3.2. Mobile Access Gateway Considerations . . . . . . . . . . . 17
3.2.1. Extensions to Binding Update List Entry . . . . . . . 17
3.2.2. Extensions to Mobile Node's Policy Profile . . . . . . 17
3.2.3. Signaling Considerations . . . . . . . . . . . . . . . 17
3.2.4. Routing Considerations for the Mobile Access
Gateway . . . . . . . . . . . . . . . . . . . . . . . 21
3.3. Mobility Options and Status Codes . . . . . . . . . . . . 22
3.3.1. IPv4 Home Address Request Option . . . . . . . . . . . 22
3.3.2. IPv4 Home Address Reply Option . . . . . . . . . . . . 23
3.3.3. IPv4 Default-Router Address Option . . . . . . . . . . 25
3.3.4. IPv4 DHCP Support Mode Option . . . . . . . . . . . . 25
3.3.5. Status Codes . . . . . . . . . . . . . . . . . . . . . 26
3.4. Supporting DHCP-Based Address Configuration . . . . . . . 27
3.4.1. DHCP Server Co-Located with the Mobile Access
Gateway . . . . . . . . . . . . . . . . . . . . . . . 28
3.4.2. DHCP Relay Agent Co-Located with the Mobile Access
Gateway . . . . . . . . . . . . . . . . . . . . . . . 31
3.4.3. Common DHCP Considerations . . . . . . . . . . . . . . 33
4. IPv4 Transport Support . . . . . . . . . . . . . . . . . . . . 35
4.1. Local Mobility Anchor Considerations . . . . . . . . . . . 37
4.1.1. Extensions to Binding Cache Entry . . . . . . . . . . 37
4.1.2. Extensions to Mobile Node's Policy Profile . . . . . . 37
4.1.3. Signaling Considerations . . . . . . . . . . . . . . . 37
4.1.4. Routing Considerations . . . . . . . . . . . . . . . . 39
4.2. Mobile Access Gateway Considerations . . . . . . . . . . . 40
4.2.1. Extensions to Binding Update List Entry . . . . . . . 40
4.2.2. Signaling Considerations . . . . . . . . . . . . . . . 40
4.3. IPsec Considerations . . . . . . . . . . . . . . . . . . . 43
4.3.1. PBU and PBA . . . . . . . . . . . . . . . . . . . . . 43
4.3.2. Payload Packet . . . . . . . . . . . . . . . . . . . . 43
5. Protocol Configuration Variables . . . . . . . . . . . . . . . 44
5.1. Local Mobility Anchor - Configuration Variables . . . . . 44
5.2. Mobile Access Gateway - Configuration Variables . . . . . 44
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RFC 5844 IPv4 Support for Proxy Mobile IPv6 May 2010
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 45
7. Security Considerations . . . . . . . . . . . . . . . . . . . 46
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 46
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 47
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 47
10.1. Normative References . . . . . . . . . . . . . . . . . . . 47
10.2. Informative References . . . . . . . . . . . . . . . . . . 48
1. Overview
The transition from IPv4 to IPv6 is a long process, and during this
period of transition, both the protocols will be enabled over the
same network infrastructure. Thus, it is reasonable to assume that a
mobile node in a Proxy Mobile IPv6 domain may operate in an IPv4-
only, IPv6-only, or dual-stack mode, and the network between the
mobile access gateway and a local mobility anchor may be an IPv4 or
an IPv6 network. It is also reasonable to expect the same mobility
infrastructure in the Proxy Mobile IPv6 domain to provide mobility to
the mobile nodes operating in IPv4, IPv6, or in dual mode and whether
the transport network is IPv4 or IPv6 network. The motivation and
scope of IPv4 support in Mobile IPv6 is summarized in [RFC4977], and
all those requirements apply to Proxy Mobile IPv6 protocol as well.
The Proxy Mobile IPv6 protocol [RFC5213] specifies a mechanism for
providing IPv6 home address mobility support to a mobile node in a
Proxy Mobile IPv6 domain. The protocol requires IPv6 transport
network between the mobility entities. The extensions defined in
this document specify IPv4 support to the Proxy Mobile IPv6 protocol
[RFC5213].
The scope of IPv4 support in Proxy Mobile IPv6 includes the support
for the following two features:
o IPv4 Home Address Mobility Support: A mobile node that is dual-
stack or IPv4-only enabled will be able to obtain an IPv4 address
and be able to use that address from any of the access networks in
that Proxy Mobile IPv6 domain. The mobile node is not required to
be allocated or assigned an IPv6 address to enable IPv4 home
address support.
o IPv4 Transport Network Support: The mobility entities in the Proxy
Mobile IPv6 domain will be able to exchange Proxy Mobile IPv6
signaling messages over an IPv4 transport.
These two features, the IPv4 home address mobility support and the
IPv4 transport support features, are independent of each other, and
deployments may choose to enable either one or both of these features
as required.
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RFC 5844 IPv4 Support for Proxy Mobile IPv6 May 2010
Figure 1 shows a typical Proxy Mobile IPv6 domain with an IPv4
transport network and with IPv4 enabled mobile nodes. The terms used
in this illustration are explained in the Terminology section.
+----+ +----+
|LMA1| |LMA2|
+----+ +----+
IPv4-LMAA -> | IPv4-LMAA-> | <-- LMAA
| |
\\ //\\
\\ // \\
\\ // \\
+---\\------------- //------\\----+
( \\ IPv4/IPv6 // \\ )
( \\ Network // \\ )
+------\\--------//------------\\-+
\\ // \\
\\ // \\
\\ // \\
IPv4-Proxy-CoA --> | | <-- Proxy-CoA
+----+ +----+
|MAG1|-----{MN2} |MAG2|
+----+ | +----+
(MN-HoA) | | | <-- (MN-HoA)
(IPv4-MN-HoA) --> | (IPv4-MN-HoA) | <-- (IPv4-MN-HoA)
{MN1} {MN3}
Figure 1: IPv4 Support for Proxy Mobile IPv6
1.1. Stated Assumptions
The following are the system and configuration requirements from the
mobility entities in the Proxy Mobile IPv6 domain for supporting the
extensions defined in this document.
o Both the mobility entities, the local mobility anchor and the
mobile access gateway are dual-stack (IPv4/IPv6) enabled.
Irrespective of the type of transport network (IPv4 or IPv6)
separating these two entities, the mobility signaling is always
based on Proxy Mobile IPv6 protocol [RFC5213].
o A deployment where a mobile access gateway uses an IPv4 private
address with NAT [RFC3022] translation devices in the path to a
local mobility anchor is not supported by this specification.
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RFC 5844 IPv4 Support for Proxy Mobile IPv6 May 2010
o The mobile node can be operating in IPv4-only, IPv6-only or in
dual mode. Based on the enabled configuration for a mobile node,
the mobile node should be able to obtain IPv4-only, IPv6-only, or
both IPv4 and IPv6 addresses for its interface and furthermore
achieve mobility support for those addresses.
o For enabling IPv4 home address mobility support to a mobile node,
it is not required that the IPv6 home address mobility support
need be enabled. However, the respective protocol(s) support,
such as IPv4 or IPv6 packet forwarding, must be enabled on the
access link between the mobile node and the mobile access gateway.
o The mobile node can obtain an IPv4 address for its attached
interface. Based on the type of link, it may be able to acquire
its IPv4 address configuration using standard IPv4 address
configuration mechanisms such as DHCP [