WDIFF

draft-ietf-netlmm-proxymip6-01.txt --> draft-ietf-netlmm-proxymip6-02.txt

NETLMM WG S. Gundavelli
Internet-Draft K. Leung
Intended status: Standards Track Cisco
Expires: December 20, 2007 March 7, 2008 V. Devarapalli
Azaire Networks
K. Chowdhury
Starent Networks
B. Patil
Nokia Siemens Networks
June 18,
September 4, 2007

Proxy Mobile IPv6
draft-ietf-netlmm-proxymip6-01.txt
draft-ietf-netlmm-proxymip6-02.txt

Status of this Memo

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This Internet-Draft will expire on December 20, 2007. March 7, 2008.

Abstract

Host based IPv6

This specification describes a network-based mobility management
protocol. It is specified in called Proxy Mobile IPv6 base
specification [RFC3775]. In that model, the mobile node and is based on Mobile IPv6

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responsible for doing the signaling

Protocol [RFC-3775]. This protocol enables mobility support to a
host within a domain and without requiring its home agent to enable
session continuity as it moves between subnets. participation in any
mobility related signaling. The design principle in the case of host-based
network-based mobility management protocol relies on the mobile node network
being in control of the mobility management. Network based mobility allows IP
session continuity for a mobile node without its involvement in
mobility management. This specification describes a protocol
solution for network based mobility management that relies on Mobile
IPv6 signaling and reuse of home agent functionality. A proxy
mobility agent in the network which manages the mobility for a mobile
node is the reason for referring to this protocol as Proxy Mobile
IPv6.

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Conventions & Terminology . . . . . . . . . . . . . . . . . . 5
2.1. Conventions used in this document . . . . . . . . . . . . 5
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
3. Proxy Mobile IPv6 Protocol Overview . . . . . . . . . . . . . 7 8
4. Proxy Mobile IPv6 Protocol Security . . . . . . . . . . . . . 11
4.1. Peer Authorization Database Entries . . . . . . . . . . . 11 12
4.2. Security Policy Database Entries . . . . . . . . . . . . . 12 13
5. Local Mobility Anchor Operation . . . . . . . . . . . . . . . 13
5.1. Extensions to Binding Cache Conceptual Entry Data Structure . . 14
5.2. Bi-Directional Tunnel Management . . . 14
5.2. Supported Home Network Prefix Models . . . . . . . . . . . 14
5.3. Routing Signaling Considerations . . . . . . . . . . . . . . . . . . 15
5.4. Local Mobility Anchor Address Discovery
5.3.1. Processing Binding Registrations . . . . . . . . . 16
5.5. Sequence Number and Time-Stamps . . 15
5.4. Timestamp Option for Message Ordering . . . 16
5.6. Route Optimizations Considerations . . . . . . . 19
5.5. Routing Considerations . . . . . 17
5.7. Mobile Prefix Discovery Considerations . . . . . . . . . . 18
5.8. Signaling Considerations . . . 21
5.5.1. Bi-Directional Tunnel Management . . . . . . . . . . . 21
5.5.2. Forwarding Considerations . . . 18
5.8.1. Initial Proxy Binding Registration . . . . . . . . . . 18
5.8.2. Extending the binding lifetime . 22
5.6. Local Mobility Anchor Address Discovery . . . . . . . . . 23
5.7. Mobile Prefix Discovery Considerations . . 20
5.8.3. De-registration of the binding . . . . . . . . 23
5.8. Route Optimizations Considerations . . . . 20
5.9. Local Mobility Anchor Operational Summary . . . . . . . . 20 24
6. Mobile Access Gateway Operation . . . . . . . . . . . . . . . 21 24
6.1. Supported Access Link Types . . Extensions to Binding Update List Entry Data Structure . . 25
6.2. Mobile Node's Policy Profile . . . . . . . . . . . 21
6.2. . . . . 26
6.3. Supported Home Network Prefix Models Access Link Types . . . . . . . . . . . 22
6.3. . . . . 26
6.4. Supported Address Configuration Models . . . . . . . . . . 22
6.4. 26
6.5. Access Authentication & Mobile Node Identification . . . . 23
6.5. 27
6.6. Acquiring Mobile Node's Policy Profile . . . . . . . . . . . . . . . 23
6.6. Conceptual Data Structures . . . . Identifier . . . . . . . . . . . . 24 27
6.7. Home Network Emulation . . . . . . . . . . . . . . . . . . 24
6.7.1. Home Network Prefix Renumbering . . . . . . . . . . . 25 28
6.8. Link-Local and Global Address Uniqueness . . . . . . . . . 26 28
6.9. Signaling Considerations . . . . . . . . . . . . . . . . . 27
6.9.1. Initial Attachment and binding registration . . . . . 27

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6.9.2. Extending the binding lifetime . . . . . . . . . . . . 28
6.9.3. De-registration of the binding . . . . . . . . . . . . 28 30
6.10. Routing Considerations . . . . . . . . . . . . . . . . . . 28 32
6.10.1. Transport Network . . . . . . . . . . . . . . . . . . 29 32
6.10.2. Tunneling & Encapsulation Modes . . . . . . . . . . . 29 32
6.10.3. Routing State . . . . . . . . . . . . . . . . . . . . 30 33
6.10.4. Local Routing . . . . . . . . . . . . . . . . . . . . 31 34
6.10.5. Tunnel Management . . . . . . . . . . . . . . . . . . 31 35
6.10.6. Forwarding Rules . . . . . . . . . . . . . . . . . . . 31 35
6.11. Interaction with DHCP Relay Agent . . . . . . . . . . . . 32 35
6.12. Home Network Prefix Renumbering . . . . . . . . . . . . . 36

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6.13. Mobile Node Detachment Detection and Resource Cleanup . . 32
6.13. 36
6.14. Allowing network access to other IPv6 nodes . . . . . . . 33 37
7. Mobile Node Operation . . . . . . . . . . . . . . . . . . . . 34 37
7.1. Booting up in Moving into a Proxy Mobile IPv6 Domain . . . . . . . . . 34 . 38
7.2. Roaming in the Proxy Mobile IPv6 Network Domain . . . . . . . . . 35 39
7.3. IPv6 Host Protocol Parameters . . . . . . . . . . . . . . 36 39
8. Message Formats . . . . . . . . . . . . . . . . . . . . . . . 37 40
8.1. Proxy Binding Update . . . . . . . . . . . . . . . . . . . 37 41
8.2. Proxy Binding Acknowledgment . . . . . . . . . . . . . . . 38 42
8.3. Home Network Prefix Option . . . . . . . . . . . . . . . . 39 42
8.4. Time Stamp Link-local Address Option . . . . . . . . . . . . . . . . 43
8.5. Timestamp Option . . . . . . 40
8.5. Status Codes . . . . . . . . . . . . . . . 44
8.6. Status Values . . . . . . . . 41 . . . . . . . . . . . . . . 45
9. Protocol Configuration Variables . . . . . . . . . . . . . . . 42 46
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 42 47
11. Security Considerations . . . . . . . . . . . . . . . . . . . 42 47
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 44 48
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 44 49
13.1. Normative References . . . . . . . . . . . . . . . . . . . 44 49
13.2. Informative References . . . . . . . . . . . . . . . . . . 45 50
Appendix A. Proxy Mobile IPv6 interactions with AAA
Infrastructure . . . . . . . . . . . . . . . . . . . 46 51
Appendix B. Supporting Shared-Prefix Model using DHCPv6 . . . . . 46 51
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 47 52
Intellectual Property and Copyright Statements . . . . . . . . . . 49 54

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1. Introduction

Mobile IPv6 [RFC-3775] is the enabler for IPv6 mobility. It requires
Mobile IPv6 client functionality in the IPv6 stack of a mobile node.
Signaling between the mobile node and home agent enables the creation
and maintenance of a binding between the mobile node's home address
and care-of-address. Mobile IPv6 has been designed to be an integral
part of the IPv6 stack in a host. However there exist IPv6 stacks
today that do not have Mobile IPv6 functionality and there would
likely be IPv6 stacks without Mobile IPv6 client functionality in the
future as well. It is desirable to support IP mobility for all hosts
irrespective of the presence or absence of mobile IPv6 functionality
in the IPv6 stack.

It is possible to support mobility for IPv6 nodes by extending Mobile
IPv6 [RFC-3775] signaling and reusing the home agent via a proxy
mobility agent in the network. This approach to supporting mobility
does not require the mobile node to be involved in the signaling
required for mobility management. The proxy mobility agent in the
network performs the signaling and does the mobility management on
behalf of the mobile node. Because of the use and extension of
Mobile IPv6 signaling and home agent functionality, it this protocol is
referred to as Proxy Mobile IPv6 (PMIP6) in the context of this document. (PMIPv6).

Network deployments which are designed to support mobility would be
agnostic to the capability in the IPv6 stack of the nodes which it
serves. IP mobility for nodes which have mobile IP client
functionality in the IPv6 stack as well as those hosts which do not,
would be supported by enabling Proxy Mobile IPv6 protocol
functionality in the network. The advantages of developing a network
based mobility protocol based on Mobile IPv6 are:

o Reuse of home agent functionality and the messages/format used in
mobility signaling. Mobile IPv6 is a mature protocol with several
implementations that have been through interoperability testing.

o A common home agent would serve as the mobility agent for all
types of IPv6 nodes.

o Addresses a real deployment need.

The problem statement and the need for a network based mobility
protocol solution has been documented in [RFC-4830]. Proxy Mobile
IPv6 is a solution that addresses these issues and requirements.

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2. Conventions & Terminology

2.1. Conventions used in this document

The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" used in
this document are to be interpreted as described in RFC 2119.

2.2. Terminology

All the general mobility related terms used in this document are to
be interpreted as defined in the Mobile IPv6 base specification [RFC-
3775].

This document adopts the terms, Local Mobility Anchor (LMA) and
Mobile Access Gateway (MAG) from the NETLMM Goals document [RFC-
4831]. This document also provides the following context specific
explanation to the following terms used in this document.

Proxy Mobile IPv6 Domain (PMIPv6-Domain)

Proxy Mobile IPv6 domain refers to the network where the mobility
management of a mobile node is handled using Proxy Mobile IPv6
protocol as defined in this specification. The Proxy Mobile IPv6
domain includes local mobility anchors and mobile access gateways
between which security associations can be setup and authorization
for sending Proxy Binding Updates on behalf of the mobile nodes
can be ensured.

Local Mobility Anchor (LMA)

Local Mobility Anchor is the home agent for the mobile node in the
Proxy Mobile IPv6 domain. It is the topological anchor point for
the mobile node's home network prefix and is the entity that
manages the mobile node's reachability state. It is important to
understand that the local mobility anchor has the functional
capabilities of a home agent as defined in Mobile IPv6 base
specification [RFC-3775] and with the additional required
capabilities for supporting Proxy Mobile IPv6 protocol as defined
in this specification.

Mobile Access Gateway (MAG)

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Mobile Access Gateway is a function that manages the mobility
related signaling for a mobile node that is attached to its access
link. It is responsible for tracking the mobile node's attachment
to the link and for signaling the mobile node's local mobility
anchor.

Mobile Node (MN)

Through out this document, the term mobile node is used to refer
to an IP node whose mobility is managed by the network. The
mobile node may be operating in IPv6 mode, IPv4 mode or in IPv4/
IPv6 dual mode. The mobile node is not required to participate in
any mobility related signaling for achieving mobility for an IP
address that is obtained in that local domain. This document
further uses explicit text when referring to a mobile node that is
involved in mobility related signaling as per Mobile IPv6
specification [RFC-3775].

LMA Address (LMAA)

The address that is configured on the interface of the local
mobility anchor and is the transport endpoint of the tunnel
between the local mobility anchor and the mobile access gateway.
This is the address to where the mobile access gateway sends the
Proxy Binding Update messages. When supporting IPv4 traversal,
i.e. when the network between the local mobility anchor and the
mobile access gateway is an IPv4 network, this address will be an
IPv4 address and will be referred to as IPv4-LMAA, as specified in
[ID-IPV4-PMIP6].

Proxy Care-of Address (Proxy-CoA)

Proxy-CoA is the address configured on the interface of the mobile
access gateway and is the transport endpoint of the tunnel between
the local mobility anchor and the mobile access gateway. The
local mobility anchor views this address as the Care-of Address of
the mobile node and registers it in the Binding Cache entry for
that mobile node. When the transport network between the mobile
access gateway and the local mobility anchor is an IPv4 network
and if the care-of address that is registered at the local
mobility anchor is an IPv4 address, the term, IPv4-Proxy-CoA is
used, as defined specified in [ID-IPV4-PMIP6].

Mobile Node's Home Address (MN-HoA)

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MN-HoA is the home address of a mobile node in a Proxy Mobile IPv6
domain. It is an address from its home network prefix obtained by the
a mobile node in that a Proxy Mobile IPv6 domain. The mobile node can
continue to use this address as long as it is attached to the
network that is in the scope of that Proxy Mobile IPv6 domain.

Mobile Node's Home Network Prefix (MN-HNP)

This is the on-link IPv6 prefix that is always present in the
Router Advertisements that the mobile node always sees
in receives on any of the
access links in that Proxy Mobile IPv6 domain. The This home network
prefix is topologically anchored at the mobile node's local
mobility anchor. The mobile node configures its interface with an
address from this prefix.

Mobile Node's Home Link

This is the link on which the mobile node obtained its initial
address configuration after it moved into that Proxy Mobile IPv6
domain. This is the link that conceptually follows the mobile
node. The network will ensure the mobile node always sees this
link with respect to the layer-3 network configuration, on any
access link that it attaches to in that proxy mobile IPv6 domain.

Mobile Node Identifier (MN-Identifier)

The identity of the a mobile node that in the Proxy Mobile IPv6 domain.
This is presented to the network
as part stable identifier of a mobile node that the access authentication. mobility
entities in a Proxy Mobile IPv6 domain can always acquire and
using which can predictably identify a mobile node. This is
typically an identifier such as Mobile Node NAI [RFC-4283], or any other type
of identifier which may be specific to the access technology. [RFC-4282].

Proxy Binding Update (PBU)

A signaling request message sent by the a mobile access gateway to a mobile
node's local mobility anchor for establishing a binding between
the mobile node's MN-HoA MN-HNP and the Proxy-CoA.

Proxy Binding Acknowledgement (PBA)

A response message sent by a local mobility anchor in response to
a Proxy Binding Update message that it received from a mobile
access gateway.

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3. Proxy Mobile IPv6 Protocol Overview

This specification describes a network-based mobility management
protocol. It is called Proxy Mobile IPv6 and is based on Mobile IPv6
[RFC-3775]. This

Proxy Mobile IPv6 protocol is intended for providing network-based
mobility

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topologically localized portion of the network and with out without requiring the
participation of the mobile node in any mobility related signaling.

Every mobile node that roams
The mobility entities in a Proxy Mobile IPv6 domain, would
typically be identified by an identifier, MN-Identifier, and using
that identifier the network will track the mobile node's policy profile can be obtained from
movements and will initiate the policy store. mobility signaling and setup the
required routing state.

The policy profile typically contains core functional entities in the
provisioned network-based mobility service characteristics NETLMM infrastructure are the
Local Mobility Anchor and other
related parameters such as the mobile node's Identifier, Mobile Access Gateway. The local
mobility anchor address, permitted address configuration modes,
roaming policy and other parameters that are essential is responsible for providing maintaining the network based mobility service.

Once a mobile node enters its Proxy Mobile IPv6 domain node's
reachability state and performs
access authentication, is the network will ensure that topological anchor point for the mobile node
is always on its
node's home network and can obtain its home address on any
access link using any of prefix. While the address configuration procedures. In
other words, there mobile access gateway is a home network prefix the
entity that is assigned to performs the mobility management on behalf of a mobile
node and conceptually that address always follows the mobile
node, where ever it roams within that Proxy Mobile IPv6 domain. From resides on the perspective of access link where the mobile node, node is
anchored. The mobile access gateway is responsible for detecting the entire Proxy Mobile IPv6
domain appears as
mobile node's movements on its home access link or a single link.

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registrations to the mobile node's local mobility anchor.

+----+ +----+
|LMA1| |LMA2|
+----+ +----+
LMAA1 -> | | <-- LMAA2
| |
\\ //\\
\\ // \\
\\ // \\
+---\\------------- //------\\----+
( \\ IPv4/IPv6 // \\ )
( \\ Network // \\ )
+------\\--------//------------\\-+
\\ // \\
\\ // \\
\\ // \\
Proxy-CoA1--> | | <-- Proxy-CoA2
+----+ +----+
|MAG1|-----[MN2] |MAG2|
+----+ | +----+
| | |
MN-HoA1 --> | MN-HoA2 | <-- MN-HoA3
[MN1] [MN3]

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Figure 1: Proxy Mobile IPv6 Domain

The

Once a mobile node enters a Proxy Mobile IPv6 scheme introduces a new function, domain and attaches to
an access network, the mobile access gateway. It is a function that is gateway on the that access link where network
after identifying the mobile node is anchored and does the mobility related signaling
on acquiring its behalf. From the perspective of the local mobility anchor, identifier, will
determine if the mobile access gateway node is a special element in authorized for network-based mobility
management service.

If the network determines that is
authorized the network-based mobility management
service needs to send Mobile IPv6 signaling messages on behalf of other be offered to that mobile nodes.

When node, the mobile node attaches to an access link connected to the
mobile access gateway, network will
ensure that the mobile node presents its identity, MN-
Identifier, as part using any of the access authentication procedure. After a
successful access authentication, the mobile access gateway obtains
the mobile node's profile from the policy store. The mobile access
gateway would have all address configuration
mechanisms permitted by the required information for it network, will be able to emulate the
mobile node's obtain an
address from its home network on the access link. It sends Router
Advertisement messages to the prefix and move anywhere in that proxy
mobile node on IPv6 domain. From the access link
advertising perspective of the mobile node's home network prefix as node, the hosted on-
link-prefix.

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The
entire proxy mobile node on receiving these Router Advertisement messages on
the access link will attempt to configure its interface either using
stateful or stateless address configuration modes, based on modes
that are permitted on that access link. At the end of IPv6 domain appears as a successful
address configuration procedure, single link, the mobile node would have obtained
an address from its home network prefix. If
ensures that the mobile node believes it is IPv4
capable and if network offers IPv4 network mobility for the mobile
node, always on the mobile node would have same link
where it obtained an IPv4 its initial address as well. configuration, even after
changing its point of attachment in that network.

The mobile node can may be operating in an IPv4-only mode, IPv6-only mode
or in
dual-mode and based dual IPv4/IPv6 mode. Based on the services enabled for that mobile, the
mobility what is enabled only for those address types. Also, in the network
between the local mobility anchor and
for that mobile node, the mobile access gateway can node will be either able to obtain an IPv4,
IPv6 or a private dual IPv4/IPv6 addresses and move any where in that Proxy
Mobile IPv6 domain. However, the specific details related to the
IPv4 with NAT translation devices. addressing or IPv4 transport support is specified in the
companion document [ID-IPV4-PMIP6].

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+-----+ +-----+ +-----+
| MN | | MAG | | LMA |
+-----+ +-----+ +-----+
| | |
MN Attached | |
| | |
| MN Attached Event |
| (Acquire MN-Id and Profile) |
| | |
| |----- PBU ----------->|
| | |
| | Accept PBU
| | (Allocate MN-HNP, Setup BCE and Tunnel)
| | |
| |<--------- PBA -------|
| | |
| Accept PBA |
| (Setup Tunnel and Routing) |
| | |
| |==== Bi-Dir Tunnel ===|
| | |
|--- Rtr Sol --------->| |
| | |
|<------- Rtr Adv -----| |
| | |
IP Address | |
Configuration | |
| | |

Figure 2: Mobile Node Attachment - Signaling Call Flow

For updating the local mobility anchor about the current location of
the mobile node, the mobile access gateway sends a Proxy Binding
Update message to the mobile node's local mobility anchor. The
message will have the mobile node's NAI identifier option and other
required options. Upon
accepting the this Proxy Binding Update message, the local mobility
anchor sends a Proxy Binding Acknowledgment message including the
mobile node's home network prefix option. prefix. It also sets up a route for the mobile node's home network prefix over creates the binding cache
entry and establishes a bi-directional tunnel to the mobile access
gateway.

The mobile access gateway on receiving this the Proxy Binding
Acknowledgment message sets up a bi-directional tunnel to the local
mobility anchor and adds a default route over the tunnel to sets up the local
mobility anchor. All traffic from data path for the mobile node gets routed to its
local mobility anchor through the bi-directional tunnel. node's

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traffic. At this point, the mobile node has a valid address from its home
network prefix, at the current point of attachment. The serving the mobile access gateway and the local mobility anchor also will have proper
routing states all the
required information for handling emulating the mobile node's home link. It
sends Router Advertisement messages to the mobile node on the access
link advertising the mobile node's home network prefix as the hosted
on-link-prefix.

The mobile node on receiving these Router Advertisement messages on
the access link will attempt to configure its interface either using
stateful or stateless address configuration modes, based on the modes
that are permitted on that access link. At the end of a successful
address configuration procedure, the mobile node will end up with an
address from its home network prefix.

Once the address configuration is complete, the mobile node has a
valid address from its home network prefix, at the current point of
attachment. The serving mobile access gateway and the local mobility
anchor also have proper routing states for handling the traffic sent
to and from the mobile node using an address from its home network
prefix.

The local mobility anchor, being the topological anchor point for the
mobile node's home network prefix, receives any packet packets that is are sent
by any corresponding node to the mobile node. Local mobility anchor
forwards the these received packet packets to the mobile access gateway through
the bi-directional tunnel. The mobile access gateway on other end of
the tunnel, after receiving the packet, removes the outer header and
forwards the packet on the access link to the mobile node.

The mobile access gateway typically acts as a default router on the
access link and any packet that the mobile node sends to any
corresponding node is received by the mobile access gateway and it
forwards the packet to its local mobility anchor through the bi-

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directional tunnel. The local mobility anchor on the other end of
the tunnel, after receiving the packet removes the outer header and
routes the packet to the destination.

After obtaining the address configuration, if the mobile node changes

4. Proxy Mobile IPv6 Protocol Security

The mobile access gateway and the local mobility anchor MUST support
and SHOULD use IPsec to protect the integrity and authenticity of the
signaling messages. The signaling messages, Proxy Binding Update and
Proxy Binding Acknowledgement, exchanged between the mobile access
gateway and the local mobility anchor are SHOULD be protected using IPsec
[RFC-4301] and using the established security association between

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them. The security association of the specific mobile node for which
the signaling message is initiated is not required for protecting
these messages.

IPsec ESP [RFC-4303] in transport mode with mandatory integrity
protection is SHOULD be used for protecting the signaling messages.
Confidentiality protection of these messages is not required.

IKEv2 is [RFC-4306] SHOULD be used to setup security associations
between the mobile access gateway and the local mobility anchor to
protect the Proxy Binding Update and Proxy Binding Acknowledgment
messages. The mobile access gateway and the local mobility anchor
can use any of the authentication mechanisms, as specified in IKEv2,
for mutual authentication.

Mobile IPv6 specification [RFC-3775] requires the home agent to
prevent a mobile node from creating security associations or creating
binding cache entries for another mobile node's home address. In the
protocol described in this document, the mobile node is not involved
in creating security associations for protecting the signaling
messages or sending binding updates. Therefore, this is not a
concern. However, the local mobility anchor MUST allow only
authorized mobile access gateways to create binding cache entries on
behalf of the mobile nodes. The actual mechanism by which the local
mobility anchor verifies if a specific mobile access gateway is
authorized to send Proxy Binding Updates on behalf of a mobile node
is outside the scope of this document. One possible way this could
be achieved is by sending a query to the policy store store, such as by using AAA
infrastructure. AAA.

4.1. Peer Authorization Database Entries

The following

This section describes PAD entries on the mobile access gateway and
the local mobility anchor. The PAD entries are only example
configurations. Note that the PAD is a logical concept and a
particular mobile access gateway or a local mobility anchor
implementation can implement the PAD in an any implementation specific

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manner. The PAD state may also be distributed across various
databases in a specific implementation.

mobile access gateway PAD:
- IF remote_identity = lma_identity_1
Then authenticate (shared secret/certificate/EAP)
and authorize CHILD_SA for remote address lma_addres_1

local mobility anchor PAD:
- IF remote_identity = mag_identity_1
Then authenticate (shared secret/certificate/EAP)

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and authorize CHILD_SAs for remote address mag_address_1

The list of authentication mechanisms in the above examples is not
exhaustive. There could be other credentials used for authentication
stored in the PAD.

4.2. Security Policy Database Entries

The following

This section describes the security policy entries on the mobile
access gateway and the local mobility anchor required to protect the
Proxy Mobile IPv6 signaling messages. The SPD entries are only
example configurations. A particular mobile access gateway or a
local mobility anchor implementation could configure different SPD
entries as long as they provide the required security.

In the examples shown below, the identity of the mobile access
gateway is assumed to be mag_1, the address of the mobile access
gateway is assumed to be mag_address_1, and the address of the local
mobility anchor is assumed to be lma_address_1.

mobile access gateway SPD-S:
- IF local_address = mag_address_1 &
remote_address = lma_address_1 &
proto = MH & local_mh_type = BU & remote_mh_type = BAck
Then use SA ESP transport mode
Initiate using IDi = mag_1 to address lma_1

local mobility anchor SPD-S:
- IF local_address = lma_address_1 &
remote_address = mag_address_1 &
proto = MH & local_mh_type = BAck & remote_mh_type = BU
Then use SA ESP transport mode

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5. Local Mobility Anchor Operation

For supporting the Proxy Mobile IPv6 scheme protocol specified in this
document, the Mobile IPv6 home agent entity, defined function, specified in Mobile IPv6
specification [RFC-3775], needs some [RFC-3775] requires
certain functional modifications and enhancements. The local
mobility anchor is an entity that has the functional capabilities of
a home agent and
with the additional required these modifications and enhanced capabilities for supporting
Proxy Mobile IPv6 protocol is referred to as defined in this
specification. This the local mobility
anchor.

The section describes the operational details of the local mobility
anchor.

The base Mobile IPv6 specification [RFC-3775], defines home agent and
the mobile node as the two functional entities. The

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5.1. Extensions to Binding Cache Entry Data Structure

Every local mobility anchor MUST maintain a new entity, the Binding Cache Entry for
each currently registered mobile access gateway. This node. Binding Cache Entry is a
conceptual data structure, described in Section 9.1 [RFC-3775].

For supporting this specification, the entity Binding Cache Entry data
structure needs to be extended with the following additional fields.

o A flag indicating whether or not this Binding Cache entry is
created due to a proxy registration. This flag is enabled for
Binding Cache entries that will participate in are proxy registrations and is turned
off for all other entries that are created due to the mobility related
signaling. From
registrations directly sent by the perspective mobile node.

o The identifier of the local mobility anchor, the registered mobile access gateway node, MN-Identifier. This
identifier is a special element in obtained from the network that has NAI Option [RFC-4283] present in
the privileges to send mobility related signaling messages on behalf received Proxy Binding Update request.

o The Link-local address of the mobile node. Typically, node on the local mobility anchor is
provisioned with interface
attached to the list of mobile access gateways authorized to
send proxy registrations.

When link. This is obtained from the Link-local
Address option, present in the local mobility anchor receives a Proxy Binding Update
message from a request.

o The IPv6 home network prefix of the registered mobile access gateway, node. The
home network prefix of the message is protected using mobile node may have been statically
configured in the IPSec Security Association established between mobile node's policy profile, or, it may have
been dynamically allocated by the local mobility
anchor and anchor. The IPv6
home network prefix also includes the mobile access gateway. corresponding prefix length.

o The interface identifier of the bi-directional tunnel established
between the local mobility anchor can
distinguish between a Proxy Binding Update message received from a and the mobile access gateway from a Binding Update message received directly
from a
where the mobile node. This distinction node is important for using currently anchored. The tunnel interface
identifier is acquired during the
right security association for validating tunnel creation.

o The 64-bit timestamp value of the most recently accepted Proxy
Binding Update and request sent for this mobile node. This is achieved by relaxing
obtained from the MUST requirement for having Timestamp option, present in the request.

5.2. Supported Home
Address Option presence in Destination Options header Network Prefix Models

This specification supports Per-MN-Prefix model and by
introducing a new flag in does not support
Shared-Prefix model. As per the Binding Update message. Per-MN-Prefix model, there will be
an unique home network prefix assigned to each mobile node and no
other node shares an address from that prefix.

The local
mobility anchor as a traditional IPSec peer can use mobile node's home network prefix is always hosted on the SPI in access
link where the
IPSec header [RFC-4306] of the received packet for locating the
correct security association and for processing the Proxy Binding
Update message in the context of mobile node is anchored. Conceptually, the entire

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For protocol simplicity, the current specification supports the Per-
MN-Prefix addressing model. In this addressing model, each mobile
node is allocated an exclusively unique September 2007

home network prefix. The
local mobility anchor in this model is just a topological anchor
point for that prefix and the prefix is physically hosted on the
access link where follows the mobile node is attached. as it moves within the
Proxy Mobile IPv6 domain. The local mobility anchor is not required
to perform any proxy ND operations [RFC-2461] for defending the
mobile node's home address on the home link. However, from the
routing perspective, the home network prefix is topologically
anchored on the local mobility anchor and is required to manage the binding
cache entry gateway to that home
network prefix.

5.3. Signaling Considerations

5.3.1. Processing Binding Registrations

Upon receiving a Proxy Binding Update request from a mobile access
gateway on behalf of the a mobile node for managing node, the local mobility session and

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also anchor MUST
process the routing state for creating request as defined in Section 10.3 [RFC-3775], with one
exception that this request is a proper route path for traffic
to/from proxy binding registration request
and hence the mobile node.

5.1. Extensions to Binding Cache Conceptual Data Structure following additional considerations must be applied.

o The local mobility anchor maintains a Binding Cache entry for each
currently registered mobile node. Binding Cache is a conceptual data
structure, MUST observe the rules described in
Section 9.1 of [RFC-3775]. For supporting
this specification, 9.2 [RFC-3775] when processing Mobility Headers in the conceptual
received Proxy Binding Cache entry needs to be
extended with the following additional fields.

o A flag indicating whether or not this Binding Cache entry is
created due to a proxy registration. This flag is enabled for
Binding Cache entries that are proxy registrations and is turned
off for all other entries that are direct registrations from the
mobile node. Update request.

o The identifier of local mobility anchor MUST identify the mobile node, MN-Identifier. This MN-
Identifier is obtained node from the NAI Option
identifier present in the NAI option of the Proxy Binding Update request [RFC-4285].

o A flag indicating whether or not
request. If the Binding Cache entry has a
home address that is on virtual interface. This flag NAI option is enabled,
if not present in the home prefix of Proxy Binding
Update request, the mobile node is configured on a virtual
interface. When local mobility anchor MUST reject the configured home prefix of a mobile is on request
and send a
virtual interface, the home agent is not required Proxy Binding Acknowledgement message with Status field
set to function as a
Neighbor Discovery proxy for the mobile node.

o The IPv6 home network prefix of the mobile node.

o The IPv6 home network prefix length of the MISSING_MN_IDENTIFIER_OPTION (Missing mobile node. node
identifier).

o The interface id of the bi-directional tunnel between If the local mobility anchor and cannot identify the mobile access gateway used for sending and
receiving node, from
the NAI option present in the request, it MUST reject the Proxy
Binding Update request and send a Proxy Binding Acknowledgement
message with Status field set to 133 (Not home agent for this
mobile node's traffic.

5.2. Bi-Directional Tunnel Management

The bi-directional tunnel between node).

o If the local mobility anchor and determines that the mobile access gateway node is used
not authorized for routing the traffic to and from the
mobile node. The tunnel hides network-based mobility management service, it
MUST reject the topology request and enables send a mobile node Proxy Binding Acknowledgement
message with Status field set to use an IP address that is topologically anchored at the PROXY_REG_NOT_ENABLED (Proxy
Registration not enabled).

o The local mobility anchor, from any attached access link anchor MUST ignore the check, specified in that proxy mobile
IPv6 domain. The base Mobile IPv6 specification
Section 10.3.1 [RFC-3775], does use
the tunneling scheme for routing traffic related to and from the mobile that
is using its home address. However, there are subtle differences presence of Home Address
destination option in the way Proxy Mobile IPv6 uses the tunneling scheme. Binding Update request.

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As in Mobile IPv4 [RFC-3344], the tunnel between the

o The local mobility anchor and MUST authenticate the mobile access gateway is typically a shared tunnel and
can be used for routing traffic streams for different mobile nodes
attached to Proxy Binding
Update request as described in Section 4.0. It MUST use the same mobile access gateway. This specification
extends that 1:1 relation between a tunnel and a binding cache entry
to 1:m relation, reflecting SPI
in the shared nature IPSec header [RFC-4306] of the tunnel.

The tunnel is creating after accepting a received packet for locating
the security association needed for processing the Proxy Binding
Update message
for a mobile node from a mobile access gateway. request.

o The created tunnel
may be shared with other mobile nodes attached local mobility anchor MUST apply the required policy checks,
as explained in Section 4.0, to verify the same sender is a trusted
mobile access gateway and with gateway, authorized to send proxy binding
registration requests on behalf of this mobile node.

o If the local mobility anchor having a binding
cache entry for those mobile nodes. Some implementations may prefer
to use static tunnels as supposed determines that the requesting node
is not authorized to creating send proxy binding registration requests, it
MUST reject the Proxy Binding Update request and tearing them down
on send a need basis.

The one end point of Proxy
Binding Acknowledgement message with Status field set to
MAG_NOT_AUTHORIZED_FOR_PROXY_REG (Not authorized to send proxy
registrations).

o If the tunnel Home Network Prefix option is not present in the address configured on the
interface of Proxy
Binding Update request, the local mobility anchor, LMAA. The other end point of
the tunnel is the address configured on the interface of anchor MUST reject the mobile
access gateway, Proxy-CoA. The details related
Proxy Binding Update request and send a Proxy Binding
Acknowledgement message with Status field set to 129
(Administratively Prohibited).

o The local mobility anchor MUST apply the supported
encapsulation modes and transport protocols is covered in detail considerations specified
in Section 6.10.2.

Implementations typically use a software timer 5.4, for managing processing the
tunnel lifetime Sequence Number field and a counter for keeping a count of all the mobiles
that are sharing
Timestamp option, in the tunnel. Proxy Binding Update request.

o The timer value will be set to local mobility anchor MUST use the
accepted binding life-time and will be updated after each periodic
registrations for extending identifier in the lifetime. If NAI
option present in the tunnel is shared Proxy Binding Update request for multiple mobile node's traffic, performing
the tunnel lifetime will be set
to Binding Cache entry existence test. If the highest binding life time across all entry does not
exist, the local mobility MUST consider this request as an initial
binding life time
that is granted for all registration request.

Initial Binding Registration:

o If the mobiles sharing that tunnel.

5.3. Routing Considerations

This section describes how the data traffic to/from Home Network Prefix option present in the mobile node
is handled at Proxy Binding
Update request has the local mobility anchor.

When a local mobility anchor is serving a mobile node, it MUST
attempt to intercept packets that are sent to any address that is in value 0::/0, the mobile node's home network prefix address range. The local mobility anchor MUST advertise
allocate a connected route in to the Routing
Infrastructure for that mobile node's home network prefix or for an
aggregated prefix with the mobile node and send a larger scope. This essentially enables
routers in Proxy Binding
Acknowledgement message with the IPv6 network to detect Home Network Prefix option
containing the allocated prefix value. The specific details on
how the local mobility anchor as
the last-hop router for that prefix.

When forwarding any packets that have the destination address
matching allocates the mobile node's home network prefix, prefix is
outside the scope of this document. The local mobility anchor
MUST encapsulate the packet with ensure the outer IPv6 header, as allocated prefix is not in use by any other mobile
node.

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specified in Generic Packet Tunneling in IPv6 specification [RFC-
2473].

o If the negotiated encapsulation header local mobility anchor is either IPv6-over-
IPv4 or IPv6-over-IPv4-UDP, as specified in the companion document,
IPv4 support unable to allocate a home network
prefix for Proxy Mobile IP6 [ID-Pv4-PMIP6], the packet must be
encapsulated mobile node, it MUST reject the request and routed as specified send a
Proxy Binding Acknowledgement message with Status field set to 130
(Insufficient resources).

o If the Home Network Prefix option present in that specification.

All the reverse tunneled packets that request has a
specific prefix hint, the local mobility anchor
receives from the tunnel, after removing the outer header before accepting
that request, MUST be
routed to the destination specified in the inner packet header.
These routed packets will have ensure the source address field set to prefix is owned by the
address from local
mobility anchor and further the mobile node's home network prefix.

5.4. Local Mobility Anchor Address Discovery

Dynamic Home Agent Address Discovery, as explained in Section 10.5 of
[RFC-3775], allows a mobile node is authorized to discover all the home agents on
its home link by sending an ICMP Home Agent Address Discovery Request
message to the Mobile IPv6 Home-Agents anycast address, derived from
its home network use
that prefix.

In Proxy Mobile IPv6, If the address of mobile node is not authorized to use that
prefix, the local mobility anchor
configured to serve MUST reject the request and send
a mobile Proxy Binding Acknowledgement message with Status field set to
NOT_AUTHORIZED_FOR_HOME_NETWORK_PREFIX (Mobile node can be discovered by not authorized
to use that prefix).

o Upon accepting the request, the local mobility
entities in one or more ways. This MAY be anchor MUST create
a configured Binding Cache entry in for the mobile node's policy profile, or it MAY be obtained through
mechanisms outside the scope of this document. node. It is important must set the fields
in the Binding Cache entry to
note the accepted value for that binding.
If there is little value a Link-local Address option present in using DHAAD message the request,
the address must be copied to the link-local address field in the current
form for discovering
Binding Cache entry.

o Upon accepting the Proxy Binding Update request, the local
mobility anchor address dynamically.
As MUST establish a mobile node moves from one mobile access gateway tunnel to the another,
the serving mobile access gateway will not predictably
gateway, as described in [RFC-2473]. Considerations from Section
5.5 must be able to
locate applied.

Binding Re-Registration:

o If the serving local mobility anchor for that mobile that has its requesting prefix in the Home Network Prefix option is a
non 0::/0 value and is different from what is present in the
currently active binding cache entry for the that mobile node. Hence, this specification
does not support Dynamic Home Agent Address Discovery protocol.

5.5. Sequence Number and Time-Stamps for Message Ordering

Mobile IPv6 [RFC-3775] uses the Sequence Number field in registration
messages as a way to ensure node, the correct packet ordering. The
local mobility anchor and the mobile node are required to manage this
counter over MUST reject the lifetime of request and send a binding.

In Proxy Mobile IPv6, the
Binding Acknowledgement message with Status field set to 129
(Administratively Prohibited).

o Upon accepting a Proxy Binding Update messages that request for extending the
lifetime of a currently active binding for a mobile node, the
local mobility anchor receives on behalf of a specific MUST update the existing Binding Cache entry
for this mobile node
may not be from node. Unless there exists an established tunnel
to the same mobile access gateway as with the previously
received message. It creates certain ambiguity same transport and
encapsulation mode, the local mobility anchor will not be predictably order the messages. This
could lead MUST create a tunnel
to the local mobility anchor processing an older message
from a mobile access gateway where gateway, as described in [RFC-2473] and also
delete the existing tunnel established with the previous mobile node was previously
attached, while ignoring
access gateway. It MUST also send a Proxy Binding Acknowledgment
message to the latest binding update message. mobile access gateway with the Status field set to
0 (Proxy Binding Update Accepted).

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Binding De-Registration:

o If the received Proxy Mobile IPv6, Binding Update request with the ordering lifetime
value of packets 0, has to be
established across packets received from multiple senders. The
sequence number scheme as specified in [RFC-3775] will not be
sufficient. A global scale, such as a time stamp, can be used to
ensure the correct ordering of the packets. This document proposes
the use of a Time Stamp Option, specified in Section 8.4, Source Address in all
Proxy Binding Update messages sent by mobile access gateways. By
leveraging the NTP [RFC-1305] service, all the entities in Proxy
Mobile IPv6 domain will be able to synchronize their respective
clocks. Having a time stamp option header, different
from what is present in Proxy the Proxy-CoA address field in its Binding Update messages
will enable
Cache entry, the local mobility anchor MAY either choose to predictably identify ignore
the
latest message from request or send a list of messages delivered in an out-of-order
fashion.

The valid Proxy Mobile IPv6 model, defined in this document requires Binding Acknowledgement message
with the
Proxy Status field set to 0 (Proxy Binding Update messages sent by Accepted).

o Upon accepting the Proxy Binding Update request for a mobile access gateway to
have node,
with the lifetime value of zero, the Time Stamp option. The local mobility anchor processing a
proxy registration MUST ignore the sequence number field and MUST the
value from the Time Stamp option to establish ordering
wait for MinDelayBeforeBCEDelete [Section 9] amount of time,
before it deletes the
received mobile node's Binding Update messages. If Cache entry. Within
this wait period, if the local mobility anchor receives a Proxy
Binding Update request message with an invalid Time Stamp
Option, for the Proxy Binding Update MUST be rejected same mobile node and from a Proxy
different mobile access gateway, with the lifetime value of
greater than zero, and if that request is accepted, then the
Binding
Acknowledgement Cache entry MUST NOT be returned in which deleted, but must be updated with
the Status field is set to
148 (invalid time stamp option).

In new values. However, the absence of Time Stamp option in local mobile anchor MUST send the
Proxy Binding Update, Acknowledgment message, immediately upon accepting
the
entities can fall back to Sequence Number scheme for message
ordering, as defined in RFC-3775. However, request.

o Upon accepting the specifics on how
different mobile access gateways synchronize request, the sequence number is
outside local mobility anchor MUST delete
the scope of this document.

When using mobile node's Binding Cache entry and remove the Time Stamp Option, Routing state
for the mobile node's home network prefix.

Constructing Proxy Binding Acknowledgement Message

o The local mobility anchor or when sending the Proxy Binding
Acknowledgment message to the mobile access gateway MUST set construct
the timestamp field to a 64-bit value
formatted message as specified by the below.

IPv6 header (src=LMAA, dst=Proxy-CoA)
Mobility header
-BA /*P flag is set*/
Mobility Options
- Home Network Time Protocol [RFC-1305]. Prefix Option
- Link-local Address Option (optional)
- Timestamp Option (optional)
- NAI Option

Proxy Binding Acknowledgment message contents

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o The
low-order 32 bits Source Address field in the IPv6 header of the NTP format represent fractional seconds, and
those bits which are not available from a time source message SHOULD
be
generated from a good source of randomness.

5.6. Route Optimizations Considerations

Mobile IPv6 route optimization, as defined in [RFC-3775], enables a
mobile node set to communicate with a corresponding node directly using
its care-of the destination address and further of the Return Routability procedure
enables received Proxy Binding
Update request.

o The Destination Address field in the corresponding node to have reasonable trust that IPv6 header of the
mobile node owns both message
SHOULD be set to the home source address and care-of address.

In of the received Proxy Mobile IPv6 model, the mobile Binding
Update request.

o If the Status field is set to a value greater less than 128, i.e.
if the binding request was rejected, then the prefix value in the
Home Network Prefix option MUST be set to the prefix value from
the received Home Network Prefix option. For all other cases, the
prefix value MUST be set to the allocated prefix value for that
mobile node.

o The Link-local Address option MUST be present in the Proxy Binding
Acknowledgement message, if the same option was present in the
corresponding Proxy Binding Update request message. If there is
an existing Binding Cache entry for that mobile node with the
link-local address value of ALL_ZERO (value not set), or if there
was no existing Binding Cache entry, then the link-local address
MUST be copied from the received Link-local Address option in the
received Proxy Binding Update request. For all other cases, it
MUST be copied from the Binding Cache entry.

o Considerations from Section 5.4 must be applied for constructing
the Timestamp option.

o The identifier in the NAI option MUST be copied from the received
Proxy Binding Update request. If the Status field value is set to
MISSING_MN_IDENTIFIER_OPTION, the NAI option MUST NOT be present
in the reply message.

o The message SHOULD be protected by using IPsec ESP, using the
security association existing between the local mobility anchor
and the mobile access gateway, created either dynamically or
statically.

5.4. Timestamp Option for Message Ordering

Mobile IPv6 [RFC-3775] uses the Sequence Number field in binding
registration messages as a way for the home agent to process the
binding updates in the order they were sent by a mobile node. The
home agent and the mobile node are required to manage this counter
over the lifetime of a binding. However, in Proxy Mobile IPv6, as
the mobile node moves from one mobile access gateway to another and
in the absence of context transfer mechanism, the serving mobile
access gateway will be unable to determine the sequence number that

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it needs to use in the signaling messages. Hence, the sequence
number scheme as specified in [RFC-3775], will be insufficient for
Proxy Mobile IPv6.

If the local mobility anchor cannot determine the sending order of
the received binding registration messages, it may potentially
process an older message sent by a mobile access gateway, where the
mobile node was previously anchored, resulting in an incorrect
binding cache entry.

For solving this problem, this specification RECOMMENDS the use of
Timestamp option [Section 8.4]. The basic principle behind the use
of timestamps in binding registration messages is that the node
generating the message inserts the current time-of-day, and the node
receiving the message checks that this timestamp is greater than all
previously accepted timestamps.

Alternatively, the specification also allows the use of Sequence
Number based scheme, as per [RFC-3775]. The sequence number MUST be
maintained on a per mobile node basis and MUST be synchronized
between the serving mobile access gateways. However, the specific
details on how a mobile node's sequence number is synchronized
between different mobile access gateways is outside the scope of this
document.

Using Timestamps based approach:

o An implementation MUST support Timestamp option. If the Timestamp
option is present in the received Proxy Binding Update request
message, then the local mobility anchor MUST include a valid
Timestamp option in the Proxy Binding Acknowledgment message that
it sends to the mobile access gateway.

o All the mobility entities in a Proxy Mobile IPv6 domain,
exchanging binding registration messages using Timestamp option
must have adequately synchronized time-of-day clocks. These nodes
SHOULD synchronize their clocks to a common time source, such as
using Network Time Protocol [RFC-1305] or in any other ways
suitable for that specific deployment.

o Upon receipt of a Proxy Binding Update message with the Timestamp
option, the local mobility anchor MUST check the timestamp field
for validity. In order for it to be considered valid, the
timestamp value contained in the Timestamp option MUST be close
enough to the local mobility anchor's time-of-day clock and the
timestamp MUST be greater than all previously accepted timestamps
in the Proxy Binding Update messages sent for that mobile node.

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o If the Timestamp option is present in the received Proxy Binding
Update message, the local mobility anchor MUST ignore the sequence
number field in the message. However, it MUST copy the sequence
number from the received Proxy Binding Update message to the Proxy
Binding Acknowledgement message.

o If the timestamp value in the received Proxy Binding Update is
valid, the local mobility anchor MUST return the same timestamp
value in the Timestamp option included in the Proxy Binding
Acknowledgment message that it sends to the mobile access gateway.

o If the timestamp value in the received Proxy Binding Update is not involved in any
valid, the local mobility related signaling anchor MUST reject the Proxy Binding
Update and send a Proxy Binding Acknowledgement message with
Status field set to TIMESTAMP_MISMATCH (Timestamp mismatch). The
message MUST also it does include the Timestamp option with the value set
to the current time-of-day on the local mobility anchor.

Using Sequence Number based approach:

o If the Timestamp option is not operate present in the received Proxy
Binding Update request, the local mobility anchor MUST fallback to
the Sequence Number based scheme. It MUST process the sequence
number field as specified in [RFC-3775]. Also, it MUST NOT
include the Timestamp option in the Proxy Binding Acknowledgment
messages that it sends to the mobile access gateway.

5.5. Routing Considerations

5.5.1. Bi-Directional Tunnel Management

o A bi-directional tunnel is established between the local mobility
anchor and the mobile access gateway with IP-in-IP encapsulation,
as described in [RFC-2473]. The tunnel end points are the Proxy-
CoA and LMAA. When using IPv4 transport with a specific
encapsulation mode, the end points of the tunnel are the IPv4-LMAA
and IPv4-Proxy-CoA, as specified in [ID-IPV4-PMIP6].

o The bi-directional tunnel is used for routing the mobile node's
data traffic between the mobile access gateway and the local
mobility anchor. The tunnel hides the topology and enables a
mobile node to use an address from its home network prefix from
any access link attached to the mobile access gateway.

o The bi-directional tunnel is established after accepting the dual- Proxy
Binding Update request message. The created tunnel may be shared

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address mode. Hence, the return routability procedure as defined in
RFC-3775 is not applicable for the proxy model.

5.7. Mobile Prefix Discovery Considerations

The ICMP Mobile Prefix Advertisement message, described in Section
6.8 and Section 11.4.3 of [RFC-3775], allows a home agent to send a
Mobile Prefix Advertisement to the mobile node.

In Proxy Mobile IPv6, the

with other mobile node's home network prefix is hosted
on the access link connected nodes attached to the same mobile access gateway. but
topologically anchored on gateway
and with the local mobility anchor. Since, there is
no physical home-link anchor having a binding cache entry
for the those mobile node's home network prefix nodes. Implementations MAY choose to use static
tunnels as supposed to dynamically creating and tearing them down
on a need basis.

o The tunnel between the local mobility anchor and as the mobile access
gateway is always on the link
where the prefix is hosted, any prefix change messages typically a shared tunnel and can just be
advertised by the used for routing
traffic streams for different mobile access gateway on nodes attached to the same
mobile access link and thus
there is no applicability of this message for Proxy Mobile IPv6.
This specification does not gateway.

o Implementations typically use Mobile Prefix Discovery.

5.8. Signaling Considerations

5.8.1. Initial Proxy Binding Registration

Upon receiving a Proxy Binding Update message from a mobile access
gateway on behalf of mobile node, the local mobility anchor MUST
process the request as defined in Section 10, of software timer for managing the base Mobile IPv6
specification [RFC-3775], with one exception that this request is
tunnel lifetime and a
proxy request, the sender is not counter for keeping a count of all the
mobile node and so nodes that are sharing the message
has to tunnel. The timer value will be processed with
set to the considerations explained in this
section.

The local mobility anchor MUST apply accepted binding life-time and will be updated after
each periodic registrations for extending the required policy checks, as
explained in Section 4.0 of this document to verify lifetime. If the sender
tunnel is a
trusted mobile access gateway, authorized to send Proxy Binding
Updates requests on behalf of that shared for multiple mobile nodes, using its own
identity. The local mobility anchor must check the local/remote
policy store tunnel lifetime
will be set to ensure the requesting node highest binding lifetime that is authorized granted to send
Proxy Binding Update messages.

The any
one of those mobile nodes sharing that tunnel.

5.5.2. Forwarding Considerations

Intercepting Packets Sent to the Mobile Node's Home Network

o When the local mobility anchor is serving a mobile node, it MUST use the MN-Identifier from
be able to receive packets that are sent to the NAI
option of mobile node's home
network. In order for it to receive those packets, it MUST
advertise a connected route in to the Proxy Binding Update message Routing Infrastructure for identifying
the mobile
node.

The node's home network prefix or for an aggregated prefix
with a larger scope. This essentially enables IPv6 routers in
that network to detect the local mobility anchor MUST ignore as the sequence number field in last-hop
router for that prefix.

Forwarding Packets Sent by the Proxy Binding Updates requests, if Mobile Node to the Time-Stamp Option is
present in Corresponding Node

o On receiving a packet from a corresponding node with the
destination address matching a mobile node's home network prefix,
the local mobility anchor MUST forward the message. It must also skip all packet through the checks related to
sequence number bi-
directional tunnel setup for that are required as per mobile node. The format of the Mobile
tunneled packet is shown below.

IPv6
specification [RFC-3775]. However, the received sequence number MUST header (src= LMAA, dst= Proxy-CoA /* Tunnel Header */
IPv6 header (src= CN, dst= MN-HNP ) /* Packet Header */
Upper layer protocols /* Packet Content*/

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be copied and returned in the Proxy Binding Acknowledgement message
sent

Figure 6: Tunneled Packets from LMA to MAG

Forwarding Packets Sent by the mobile access gateway.

The local mobility anchor before accepting a Proxy Binding Update
request containing Corresponding Node to the Home Network Prefix Option with a specific
prefix, MUST ensure Mobile Node

o All the prefix is owned by reverse tunneled packets that the local mobility anchor
and further
receives from the mobile node is authorized access gateway, after removing the tunnel
header MUST be routed to use that prefix. If the
Home Network Prefix Option has destination specified in the value 0::/0, inner
packet header. These routed packets will have the local mobility
anchor MUST allocate a prefix for source address
field set to the mobile node and send node's home address.

5.6. Local Mobility Anchor Address Discovery

Dynamic Home Agent Address Discovery, as explained in Section 10.5
[RFC-3775], allows a Proxy
Binding Acknowledgement message with mobile node to discover all the home agents on
its home link by sending an ICMP Home Network Prefix Option
containing Agent Address Discovery Request
message to the allocated value. Mobile IPv6 Home-Agents anycast address, derived from
its home network prefix.

The specific details on how DHAAD message in the current form cannot be used in Proxy Mobile
IPv6 for discovering the address of the mobile node's local mobility
anchor. In Proxy Mobile IPv6, the local mobility anchor allocates will not be
able to receive any messages sent to the Mobile IPv6 Home-Agents
anycast address corresponding to the mobile node's home network
prefix, as the prefix is outside
the scope not hosted on any of this document.

Upon accepting a Proxy Binding Update request from a its interfaces.
Further, the mobile access
gateway, gateway will not predictably be able to
locate the serving local mobility anchor must check if there exists a
binding cache entry for that mobile node, identified using the MN-
Identifier, that was created due to a direct registration from has the mobile node. If there exists a node's
binding cache entry with entry. Hence, this specification does not support
Dynamic Home Agent Address Discovery protocol.

In Proxy Mobile IPv6, the proxy
registration flag turned off, address of the local mobility anchor MUST NOT
modify that binding state, instead it must create
configured to serve a tentative binding
cache entry and update mobile node can be discovered by the tentative binding cache mobility
entities in other ways. This may be a configured entry fields in the mobile
node's policy profile, or it may be obtained through mechanisms
outside the scope of
that binding cache entry.

Upon receiving a Binding Update request from this document.

5.7. Mobile Prefix Discovery Considerations

The ICMP Mobile Prefix Advertisement message, described in Section
6.8 and Section 11.4.3 of [RFC-3775], allows a mobile node with
lifetime value set home agent to 0, from a tunnel between itself and send a trusted
Mobile Prefix Advertisement to the mobile access gateway, node.

In Proxy Mobile IPv6, the local mobility anchor upon accepting that
de-registration message, MUST forward mobile node's home network prefix is hosted
on the Binding Acknowledgement
message in access link connected to the tunnel from where mobile access gateway. but it received the Binding Update
request. It must also replace the binding cache entry with is
topologically anchored on the
tentative binding cache entry and enable routing local mobility anchor. Since, there is
no physical home-link for the mobile node's home network prefix through the proxy mobile IPv6 tunnel.

Upon accepting this Proxy Binding Update message, on
the local mobility anchor must create a Binding Cache entry and must set up a tunnel to as the mobile node is always on the
link where the prefix is hosted, any prefix change messages can just

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be advertised by the mobile access gateway serving on the access link and
thus there is no applicability of this message for Proxy Mobile IPv6.
Hence, this specification does not support Mobile Prefix Discovery.

5.8. Route Optimizations Considerations

The Route Optimization in Mobile IPv6, as defined in [RFC-3775],
enables a mobile node to communicate with a corresponding node
directly using its care-of address and further the Return Routability
procedure enables the corresponding node to have reasonable trust
that the mobile node. This bi-
directional tunnel between node is reachable at both its home address and
care-of address.

In Proxy Mobile IPv6, the local mobile node is not involved in any mobility anchor
related signaling. The mobile node uses only its home address for
all its communication and the Care-of address (Proxy-CoA) is not
visible to the mobile node. Hence, the Return Routability procedure
as defined in Mobile IPv6 cannot be used in Proxy Mobile IPv6.

6. Mobile Access Gateway Operation

The Proxy Mobile IPv6 protocol described in this document, introduces
a new functional entity, the Mobile Access Gateway (MAG). The mobile
access gateway is used the entity that is responsible for routing detecting the
mobile node's traffic.

The Proxy Binding Acknowledgment message must be constructed as shown
below.

IPv6 header (src=LMAA, dst=Proxy-CoA)
Mobility header
-BA /*P flag is set*/
Mobility Options
- Home Network Prefix Option

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- TimeStamp Option (optional)
- NAI Option

Proxy Binding Acknowledgment message contents

5.8.2. Extending movements on its access link and sending the binding lifetime

Upon accepting the Proxy Binding Update request for extending the
lifetime of a currently active binding,
registration requests to the local mobility anchor
MUST update anchor. In essence, the lifetime for that binding and send
mobile access gateway performs mobility management on behalf of a Proxy Binding
Acknowledgment message to the
mobile node.

The mobile access gateway. gateway is a function that typically runs on an
access router. However, implementations MAY choose to split this
function and run it across multiple systems. The Proxy
Binding Acknowledgment message MUST be constructed as specified in
Section 5.8.1.

5.8.3. De-registration of the binding

Upon accepting the Proxy Binding Update request sent with specifics on how
that is achieved is beyond the
lifetime value scope of zero, the local mobility anchor MUST delete this document.

The mobile access gateway has the
binding from its Binding Cache and MUST send a Proxy Binding
Acknowledgment message to following key functional roles:

o It is responsible for detecting the mobile node's movements on the
access gateway. The message
MUST be constructed as specified in Section 6.9.1.

The local mobility anchor MUST also remove link and for initiating the prefix route over mobility signaling with the
tunnel for that
mobile node's home network prefix.

5.9. Local Mobility Anchor Operational Summary

o For supporting this scheme, the local mobility anchor MUST satisfy
all the requirements listed in Section 8.4 anchor.

o Emulation of Mobile IPv6
specification [RFC-3775] the mobile node's home link on the access link by
sending Router Advertisements with the following considerations. mobile node's home network
prefix information.

o For supporting Responsible for setting up the per-MN-Prefix addressing model as defined in
this specification, data path for enabling the local mobility anchor service MUST NOT be
tied to a specific interface. It SHOULD be able to accept Proxy
Binding Update requests sent mobile
node to any of the addresses configured on
any of configure an address from its interfaces.

o The requirement for a home agent network prefix and use
it from its access link.

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6.1. Extensions to Binding Update List Entry Data Structure

Every mobile access gateway MUST maintain a list of home agents
for Binding Update List.
Each entry in the Binding Update List represents a mobile node's home link is not applicable for the local
mobility anchor, when supporting Per-MN-Prefix addressing model.

o The binding with its local mobility anchors SHOULD drop all HoTI messages received
for anchor. The Binding Update
List is a home address that has corresponding conceptual data structure, described in Section 11.1 [RFC-
3775].

For supporting this specification, the conceptual Binding Cache Update List
entry data structure needs be extended with the proxy registration flag set. following additional
fields.

o The local mobility anchor must handle Identifier of the attached mobile node, MN-Identifier. This
identifier is acquired during the mobile node's data
traffic as explained in attachment to the
access link or through mechanisms outside the Routing Considerations section scope of this

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document.

6. Mobile Access Gateway Operation

o The Proxy Mobile IPv6 scheme specified in this document, introduces a
new functional entity, Link-layer address of the Mobile Access Gateway (MAG). It is mobile node. This address can be
acquired from the
entity that detects received Router Solicitation messages from the
mobile node or during the mobile node's movements and initiates attachment to the
signaling with access
network.

o The IPv6 home network prefix of the attached mobile node. The
home network prefix of the mobile node is acquired from the mobile
node's local mobility anchor for updating
the route to through the mobile node's received Proxy Binding
Acknowledgment messages. The IPv6 home address. In essence, network prefix also
includes the mobile
access gateway performs mobility management on behalf corresponding prefix length.

o The Link-local address of the mobile
node.

From node on the perspective interface
attached to the access link.

o The IPv6 address of the local mobility anchor, anchor serving the attached
mobile access
gateway node. This address is a special element in acquired from the network that sends Mobile IPv6
signaling messages on behalf mobile node's
policy profile.

o The interface identifier of a the access link where the mobile node, but using its own
identity. It node
is the entity that binds currently attached. The interface identifier is acquired
during the mobile node's home address attachment to an address on its own the access interface. link.

o The interface identifier of the bi-directional tunnel between the
mobile access gateway has node's local mobility anchor and the following functional roles.

o Responsible for detecting mobile access gateway.
The tunnel interface identifier is acquired during the tunnel
creation.

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6.2. Mobile Node's Policy Profile

A mobile node's attachment or
detachment on policy profile contains the connected access link and for initiating essential operational
parameters that are required by the
mobility signaling with network entities for managing the
mobile node's local mobility anchor.

o Emulation of service. These policy profiles are stored in
a local or a remote policy store, the mobile node's home link on the access link.

o Registering the binding state at gateway and the mobile node's
local mobility
anchor.

o Responsible for setting up the data path for enabling the mobile
node anchor MUST be able to use an address from its home network prefix and use it
from the access link. obtain a mobile node's policy
profile. The policy profile may also be handed over to a serving
mobile access gateway is as part of a function that typically runs on an
access router. However, implementations MAY choose to split this
function and run it across multiple systems. context transfer procedure during
a handoff. The specifics exact details on how
that is this achieved is beyond outside the
scope of this document.

6.1. However, this specification requires that a
mobile access gateway serving a mobile node MUST have access to its
policy profile.

The following are the mandatory fields of the policy profile:

o The mobile node's identifier (MN-Identifier)

o The IPv6 address of the local mobility anchor (LMAA)

o Supported address configuration procedures on the link (Stateful,
Stateless or both)

The following are the optional fields of the policy profile:

o The mobile node's IPv6 home network prefix (MN-HNP)

6.3. Supported Access Link Types

This specification supports only point-to-point access link types and
thus it assumes that the link between the mobile node and the mobile
access gateway is a dedicated point-to-point access link types and
thus it assumes that the mobile node and the mobile access gateway
are the only two nodes present on that link.
The assumed properties for the point-to-point link type are just as
assumed by the Neighbor Discovery specification [RFC-2461] for that
link type. access link. The link is assumed to
have multicast capability and the

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interfaces connecting to the link can be configured with a link-local
address.

Support for shared links or other link types is left for the future
work.

6.2. Supported Home Network Prefix Models

This specification supports Per-MN-Prefix model and does not support
Shared-Prefix model. As per the Per-MN-Prefix model, there will be a
unique home network prefix assigned for each mobile node and no other
host shares an address from that prefix. The prefix is always hosted
on the access link where the mobile node is anchored. Conceptually,
the prefix follows the mobile node as it moves within the proxy
mobile IPv6 domain. However, from the routing perspective, the home
network prefix is topologically anchored on the local mobility
anchor.

6.3. capability.

6.4. Supported Address Configuration Models

A mobile node in the proxy mobile Proxy Mobile IPv6 domain can configure one or
more IPv6 addresses on its interface using Stateless or Stateful
address autoconfiguration procedures. The Router Advertisement
messages sent on the access link, specify the address configuration
methods permitted on that access link for that mobile node. The
exact semantics of the flags that are enabled, the options that are
carried in these advertisement messages is as per the Neighbor
Discovery specification [RFC-2461]. However,
the advertised flags with respect the address configuration will be
consistent for a mobile node, on any of the access links in that proxy mobile
Proxy Mobile IPv6 domain. Typically, these configuration settings
will be based on the domain wide policy or based on a policy specific to each mobile node.
This specification requires that all the mobile access gateways in a
given proxy mobile IPv6 domain MUST ensure that the permitted address
configuration procedures or the address configuration parameters that
are sent in the Router Advertisements are consistent for a mobile
node when attached to on any of the access links in the proxy policy specific
to each mobile node.

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When stateless address autoconfiguration is supported on the link,
the mobile node can generate one or more IPv6 addresses by combining
the network prefix advertised on the access link with an interface
identifier, using the techniques described in Stateless
Autoconfiguration specification [RFC-2462] or in as per Privacy
extension specification [RFC-3041].

When stateful address autoconfiguration is supported on the link, the
mobile node obtains can obtain the address configuration from the DHCPv6
server

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specification [RFC-3315].

In addition to this,

Additionally, other address configuration mechanisms specific to the
access link between the mobile node and the mobile access gateway may
also be used for pushing the address configuration to the mobile
node.

6.4.

6.5. Access Authentication & Mobile Node Identification

When a mobile node attaches to an access link connected to the mobile
access gateway, the deployed access security protocols on that link
will ensure that the network-based mobility management service is
offered only after authenticating and authorizing the mobile node for
that service. The exact specifics on how this is achieved or the
interactions between the mobile access gateway and the access
security service is outside the scope of this document. This
specification goes with the stated assumption of having an
established trust and a secured communication link between the mobile
node and mobile access gateway, before the protocol operation begins.
The specification also requires that the mobile access gateway MUST
be able to identify the mobile node by its MN-Identifier and it must
also be able to associate this identity to the sender of any IPv4 or
IPv6 packets on the access link. The mobile access gateway MUST also
be able to obtain the mobile node's policy profile using the MN-
Identifier.

6.5. Mobile Node's Policy Profile

A mobile node's policy profile contains the essential operational
parameters that are required by the network entities for managing the
mobile node's mobility service. These policy profiles are stored in
a local or a remote policy store, the mobile access gateway and the
local mobility anchor MUST be able to obtain a mobile node's policy
profile using its MN-Identifier. The policy profile may also be
handed over to a serving
SHOULD ensure that the network-based mobility management service is
offered only after authenticating and authorizing the mobile access gateway as part of a context
transfer procedure during a handoff. node for
that service. The exact details specifics on how this is achieved or the
interactions between the mobile access gateway and the access
security service is outside the scope of this document. However, this This
specification requires that a mobile access gateway serving a mobile
node MUST have access to its policy profile.

The following are goes with the mandatory fields stated assumption of having an
established trust between the policy profile:

o The mobile node's identifier (MN-Identifier)

o The IPv6 address of node and mobile access gateway,
before the local mobility anchor (LMAA)

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6.6. Acquiring Mobile IPv6 June 2007

o Supported address configuration procedures on the link (Stateful,
Stateless or both)

The following are the optional fields of Node's Identifier

All the policy profile:

o The mobile node's IPv6 home network prefix (MN-HoA)

o The mobile node's IPv6 home network prefix length

6.6. Conceptual Data Structures

Every mobile access gateway MUST maintain a Binding Update List for
each currently attached mobile node. The Binding Update List is a
conceptual data structure, described entities in Section 11.1 of a Proxy Mobile IPv6
base specification [RFC-3775]. For supporting this specification,
the conceptual Binding Update List data structure must domain MUST be extended
with the following new additional fields.

o The Identifier of the able
to identify a mobile node, using its MN-Identifier.

o The MAC address of the mobile node's connected interface.

o The IPv6 home network prefix of the mobile node.

o The This identifier
MUST be stable across the Proxy Mobile IPv6 home network prefix length of domain and the mobile node.

o The interface entities
must be able to use this identifier of in the point-to-point link to signaling messages.
Typically, this identifier is obtained as part of the mobile
node. access
authentication or through other means as specified below.

o The interface identifier of the tunnel between the mobile access
gateway and the mobile node's local mobility anchor.

6.7. Home Network Emulation

One of node that the key functions of a mobile access gateway is to emulate the
mobile node's home network prefix on
obtains as part of the access link. It must
ensure, the mobile node believes it is still connected to its home
link authentication or on from the link where it obtained its address configuration after
it moved into that proxy mobile IPv6 domain.

After detecting new mobile node on its access link and after notified
network attachment event, can be a
successful access authentication temporary identifier and authorization of the mobile node
for network-based mobility service, this
identifier may also change at each re-authentication. However,
the mobile access gateway MUST be able to
emulate authenticate the mobile node's home link by sending
node based on this identifier and MUST be able to obtain the Router
Advertisements with MN-
Identifier from the mobile node's home network prefix policy store, such as from the
hosted on-link prefix. The Router Advertisement MUST be sent in RADIUS
attribute, Chargeable-User-Identifier.

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response to a Router Solicitation message that it received from the
mobile node.

o The Router Advertisement messages MAY also be sent
periodically, based on the interface configuration on the mobile
access gateway.

For emulating the mobile node's home link on the access link, MN-Identifier that the policy store delivers to the mobile
access gateway must know MAY NOT be the home network prefix true identifier of the mobile
node for constructing the Router Advertisement. Typically and as a
default method, node.
However, the mobile mobility access gateway learns the mobile node's
home network prefix information from the Proxy Binding
Acknowledgement message, it received in response MUST be able to use this
identifier in the Proxy Binding
Update message that it sent to signaling messages exchanged with the mobile node's local
mobility
anchor for that mobile node.

However, it is also possible, the anchor.

o The mobile node's home network prefix
information may access gateway MUST be statically configured in able identify the mobile node's policy
profile or node by
its MN-Identifier and it may MUST be handed over able to associate this identity
to the mobile sender of any IPv4 or IPv6 packets on the access gateway as part link.

6.7. Home Network Emulation

One of a context transfer procedure. If the key functions of a mobile access gateway can
predictably know is to emulate the
mobile node's home network prefix information,
it MAY choose to send the Router Advertisement prior to receiving the
Proxy Binding Acknowledgement message from the local mobility anchor.
However, in the event, the local mobility anchor rejects the Proxy
Binding Update message, or if on the prefix that is received from access link. It must ensure, the
local mobility anchor for that
mobile node believes it is a different prefix than
what the mobile access gateway previously advertised, the mobile
access gateway MUST withdraw the prefix by sending a Router
Advertisement message with zero lifetime for still connected to its home link or on the prior advertised
prefix.

If
link where it obtained its initial address configuration after it
moved into that Proxy Mobile IPv6 domain.

For emulating the access mobile node's home link connecting on the mobile access gateway and the
mobile node is a point-to-point link, the
mobile access gateway must be able to send Router Advertisements
advertising a specific the mobile node's home network prefix is received only by the
respective mobile node and hence there is clearly a unique other address
configuration parameters consistent with its home link for
each mobile node that is attached to that properties.

Typically, the mobile access gateway.

6.7.1. Home Network Prefix Renumbering

If gateway learns the mobile node's home
network prefix gets renumbered information from the received Proxy Binding
Acknowledgement message or becomes
invalid during it may be obtained from the middle of a mobility session, mobile node's
policy profile. However, the mobile access gateway MUST withdraw SHOULD send the prefix by sending a
Router Advertisement on
the access link with zero prefix lifetime for Advertisements advertising the mobile node's home network prefix. Also,
prefix only after successfully completing the local mobility anchor and binding registration
with the mobile
access gateway MUST delete the routing state for that prefix.
However, the specific details on how the node's local mobility anchor
notifies the mobile access gateway is outside the scope of this
document.

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6.8. Link-Local and Global Address Uniqueness

A mobile node in the proxy mobile Proxy Mobile IPv6 domain, as it moves from one
mobile access gateway to the other, it will continue to detect its
home network and thus making the node it believe it is still on the same link.
Every time the mobile node attaches to a new link, the event related
to the interface state change, will trigger the mobile node to
perform DAD operation on the link-local and global addresses.
However, if the mobile node is DNAv6 enabled, as specified in [ID-DNAV6], [ID-
DNAV6], it may not detect the link change due to DNAv6 optimizations
and hence
it will may not trigger the duplicate address detection (DAD) procedure
for establishing the link-local address uniqueness on that new link.
Further, if the mobile node uses an interface identifier that is not
based on EUI-64 identifier, such as specified in IPv6 Stateless
Autoconfiguration specification [RFC-2462], there is a possibility,
with the odds of 1 to billion, of a link-local address collision
between the two neighbors, the mobile node and the mobile neighbors on that access
gateway. link.

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One of the workarounds for this issue is to set the DNAv6
configuration parameter, DNASameLinkDADFlag to TRUE and that will
force the mobile node to redo DAD operation every time the interface
comes up, even when DNAv6 does detect a link change .

However, this issues will not impact point-to-point links based on
PPP session. Each time the mobile node moves and attaches to a new
mobile access gateway, either the PPP session [RFC-1661] is
reestablished or the PPP session may be moved as part of context
transfer procedures between the old and the new mobile access
gateway.

When the mobile node tries to establish a PPP session with the mobile
access gateway, the PPP goes through the Network layer Protocol phase
and the IPv6 Control Protocol, IPCP6 [RFC-2472] gets triggered. Both
the PPP peers negotiate a unique identifier using Interface-
Identifier option in IPV6CP and the negotiated identifier is used for
generating a unique link-local address on that link. Now, if the
mobile node moves to a new mobile access gateway, the PPP session
gets torn down with the old mobile access gateway and a new PPP
session gets established with the new mobile access gateway, and the
mobile node obtains a new link-local address. So, even if the mobile
node is DNAv6 capable, the mobile node always configures a new link-
local address when ever it moves to a new link.

If the PPP session state is moved to the new mobile access gateway,
as part of context transfer procedures that are in place, there will
not be any change to the interface identifiers of the two nodes on
that point-to-point change. The whole link is moved to the new

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mobile access gateway and there will not be any need and there will not be any need for establishing
link-local address uniqueness on that link.

Alternatively, this specification allows the mobile access gateway to
upload the mobile node's link-local address to the local mobility
anchor using the Link-local Address option, exchanged in the binding
registration messages. The mobile access gateway can learn the
mobile node's link-local address, by snooping the DAD messages sent
by the mobile node for establishing the link-local address uniqueness
on that the access link. Subsequently, at each handoff, the mobile access
gateway can obtain this address from the local mobility anchor and
can change its own link-local address, if it detects an address
collision.

This issue is not relevant to the mobile node's global address.
Since, there is a unique home network prefix for each mobile node,
the uniqueness for the mobile node's global address is ensured assured on the
access link.

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6.9. Signaling Considerations

6.9.1.

Initial Attachment and binding registration

o After detecting a new mobile node on its access link after a
successful access authentication and authorization, link, the mobile
access gateway MUST send a Proxy Binding Update message to the
mobile node's local mobility anchor.

The Proxy Binding Update message must be constructed as shown below.

IPv6 header (src=Proxy-CoA, dst=LMAA)
Mobility header
-BU /*P flag is set*/
Mobility Options
- Home Network Prefix Option*
- TimeStamp Option (optional)
- NAI Option

*Home Network Prefix option may contain 0::/0 or a specific prefix.

Proxy Binding Update message contents

o The Proxy Binding Update message that the mobile access gateway
sends to the mobile node's local mobility anchor MUST have the NAI
option, identifying the mobile node, the Home Network Prefix
option and optionally the Time Stamp option SHOULD be present. The Time Stamp Timestamp option is not required if the mobile access gateway can send or a valid sequence number that matches the sequence number maintained by the
local mobility anchor for that mobile node in its binding cache
entry. The message MUST be protected by using IPsec ESP, using the
security association existing between the local mobility anchor and
the mobile access gateway, created either dynamically or statically.
number.

o If the mobile access gateway learns the mobile node's home network
prefix either from its policy store or from other means, the
mobile access gateway MAY choose to specify the same in the Home
Network Prefix option for requesting the local mobility anchor to register

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allocate that prefix. If the specified value is 0::/0, then the
local mobility anchor will allocate consider this as a request for prefix to
allocation.

o If the mobile node.

After receiving access gateway receives a Proxy Binding
Acknowledgment with the status code
indicating the acceptance of Status field value set to 0 (Proxy Binding
Update accepted), the Proxy mobile access gateway MUST create Binding Update,
Update List entry for the mobile
access gateway MUST node and must setup a tunnel to
the mobile node's local mobility anchor, as explained in section
6.10. The mobile access gateway MUST also add a policy route for
tunneling all the packets that it receives from the mobile node to
its local mobility anchor.

o If the local mobility anchor rejects the mobile access gateway receives a Proxy Binding Update
message,
Acknowledgment with the Status field value greater than 128
(binding request is rejected), the mobile access gateways MUST NOT
advertise the mobile node's home network prefix on the access link
and there by denying mobility service to the mobile node.

6.9.2.

Extending the binding lifetime

o For extending the lifetime of a currently existing binding at the
local mobility, the mobile access gateway MUST send a Proxy
Binding Update message with a specific lifetime. The message MUST be
constructed as specified in Section 6.9.1.

6.9.3. De-registration message, before the expiry of the currently
accepted binding.

De-Registration of the binding

o At any point, the mobile access gateway detects that the mobile
node has moved away from its access link, it MUST send a Proxy Binding
Update message Proxy

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Binding Update message to the mobile node's local mobility anchor
with the lifetime value set to zero.

o The mobile access gateway MUST also remove the default route over
the tunnel for that mobile node and delete the Binding Update List
for that mobile node, either upon receiving an Proxy Binding
Acknowledgment message from the local mobility anchor or after a
certain timeout waiting for the acknowledgment message.

Constructing Proxy Binding Update Message

o The mobile access gateway when sending the Proxy Binding Update
request to the local mobility anchor MUST construct the message as
specified below.

IPv6 header (src=Proxy-CoA, dst=LMAA)
Mobility header
-BU /*P & A flags are set*/
Mobility Options
- Home Network Prefix option
- Link-local Address option (Optional)
- Timestamp Option (optional)
- NAI Option

Proxy Binding Update message contents

o The Source Address field in the IPv6 header of the message SHOULD
be set to the address of the mobile access gateway.

o The Destination Address field in the IPv6 header of the message
SHOULD be set to the local mobility anchor address.

o The Home Network Prefix option MUST be present. The prefix value
may be set 0::/0 or to a specific value.

o The Link-local Address option MAY be present. The value may be
set to ALL_ZERO or the mobile node's local mobility anchor with link-local address.

o Considerations from Section 5.4 must be applied for constructing
the
lifetime value set to zero. Timestamp option.

o The message NAI option MUST be constructed as
specified in Section 6.9.1.

The mobile access gateway MUST also remove the default route over present, the
tunnel for that mobile node and delete identifier field in the Binding Update List for
that option
MUST be set to mobile node, either upon receiving an node's identifier, MN-Identifier.

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Acknowledgment Mobile IPv6 September 2007

o The message from SHOULD be protected by using IPsec ESP, using the
security association existing between the local mobility anchor or after a
certain timeout waiting for
and the acknowledgment message. mobile access gateway, created either dynamically or
statically.

6.10. Routing Considerations

This section describes how the mobile access gateway handles the
traffic to/from the mobile node that is attached to one of its access
interface.

Proxy-CoA LMAA
| |
+--+ +---+ +---+ +--+
|MN|----------|MAG|======================|LMA|----------|CN|
+--+ +---+ +---+ +--+

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IPv6 Tunnel

6.10.1. Transport Network

The transport network between the local mobility anchor and the
mobile access can be either an IPv6 or IPv4 network. However, this
specification only deals with the scenario where the transport
network between the mobility entities is IPv6-only and requires
reachability between the local mobility anchor and the mobile access
gateway over IPv6 transport. Just as in Mobile IPv6 specification
[RFC-3775], the negotiated tunnel transport between the local
mobility anchor and the mobile access gateway is IPv6, by default.
The companion document, IPv4 support for Proxy Mobile IPv6 [IPv4-
PMIP6-SPEC]
document [ID-IPV4-PMIP6] specifies the required extensions for
negotiating IPv4
tunneling mechanism transport and a specific the corresponding encapsulation mode mode,
for supporting this protocol operation over IPv4 transport network. operation.

6.10.2. Tunneling & Encapsulation Modes

The IPv6 address that a mobile node uses from its home network prefix
is topologically anchored at the local mobility anchor. For a mobile
node to use this address from an access network attached to a mobile
access gateway, proper tunneling techniques have to be in place.
Tunneling hides the network topology and allows the mobile node's
IPv6 datagrams to be encapsulated as a payload of another IPv6 packet
and be routed between the local mobility anchor and the mobile access
gateway. The Mobile IPv6 base specification [RFC-3775] defines the
use of IPv6-over-IPv6 tunneling, between the home agent and the
mobile node and this specification extends the use of the same
tunneling mechanism between the local mobility anchor and the mobile
access gateway.

On most operating systems, tunnels are implemented as a virtual
point-to-point interface. The source and the destination address of
the two end points of this virtual interface along with the
encapsulation mode are specified for this virtual interface. Any

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packet that is routed over this interface, get encapsulated with the
outer header and the addresses as specified for that point to point
tunnel interface. For creating a point to point tunnel to any local
mobility anchor, the mobile access gateway may implement a tunnel
interface with the source address field set to its Proxy-CoA address
and the destination address field set to the LMA address.

The following are the supported packet encapsulation modes that can
be used by the mobile access gateway and the local mobility anchor
for routing mobile node's IPv6 datagrams.

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o IPv6-In-IPv6 - IPv6 datagram encapsulated in an IPv6 packet. This
mechanism is defined in the Generic Packet Tunneling for IPv6
specification [RFC-2473].

o IPv6-In-IPv4 - IPv6 datagram encapsulation in an IPv4 packet. The
details related to this encapsulation mode and the specifics on
how this mode is negotiated is specified in the companion
document, IPv4 support for Proxy Mobile IPv6 [ID-IPv4-PMIP6]. [ID-IPV4-PMIP6].

o IPv6-In-IPv4-UDP - IPv6 datagram encapsulation in an IPv4 UDP
packet. The details related to this mode are covered in the
companion document, IPv4 support for Proxy Mobile IPv6 [IPv4-
PMIP6-SPEC]. [ID-IPV4-
PMIP6].

6.10.3. Routing State

The following section explain the routing state for a mobile node on
the mobile access gateway. This routing state reflects only one
specific way of implementation and one MAY choose to implement it in
other ways. The policy based route defined below acts as a traffic
selection rule for routing a mobile node's traffic through a specific
tunnel created between the mobile access gateway and that mobile
node's local mobility anchor and with the specific encapsulation
mode, as negotiated.

The below example identifies the routing state for two visiting
mobile nodes, MN1 and MN2 with their respective local mobility
anchors LMA1 and LMA2.

For all traffic from the mobile node, identified by the mobile node's
MAC address, ingress interface or source prefix (MN-HNP) to
_ANY_DESTINATION_ route via interface tunnel0, next-hop LMAA.

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+==================================================================+
| Packet Source | Destination Address | Destination Interface |
+==================================================================+
| MAC_Address_MN1, | _ANY_DESTINATION_ | Tunnel0 |
| (IPv6 Prefix or |----------------------------------------------|
| Input Interface) | Locally Connected | Tunnel0 |
+------------------------------------------------------------------+
| MAC_Address_MN2 MAC_Address_MN2, | _ANY_DESTINATION_ | Tunnel1 |
+ (IPv6 Prefix or -----------------------------------------------|
| Input Interface | Locally Connected | direct |
+------------------------------------------------------------------+

Example - Policy based Route Table

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Example - Tunnel Interface Table

6.10.4. Local Routing

If there is data traffic between a visiting mobile node and a
corresponding node that is locally attached to an access link
connected to the mobile access gateway, the mobile access gateway MAY
optimize on the delivery efforts by locally routing the packets and
by not reverse tunneling them to the mobile node's local mobility
anchor. However, this has an implication on the mobile node's
accounting and policy enforcement as the local mobility anchor is not
in the path for that traffic and it will not be able to apply any
traffic policies or do any accounting for those flows.

This decision of path optimization SHOULD be based on the configured
policy configured on the mobile access gateway, but enforced by the
mobile node's local mobility anchor. The specific details on how
this is achieved is beyond of the scope of this document.

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6.10.5. Tunnel Management

All the considerations mentioned in Section 5.2, 5.5.1, for the tunnel
management on the local mobility anchor apply for the mobile access
gateway as well.

As explained in Section 5.2, the life of the Proxy Mobile IPv6 tunnel
should not be based on a single visiting mobile node's lifetime. The
tunnel may get created as part of creating a mobility state for a
visiting mobile node and later the same tunnel may be associated with
other mobile nodes. So, the tearing down logic of the tunnel must be
based on the number of visitors over that tunnel.

6.10.6. Forwarding Rules

Upon receipt of an encapsulated packet sent to its configured Proxy-
CoA address i.e. on receiving a packet from a tunnel, the mobile
access gateway MUST use the destination address of the inner packet
for forwarding it to the interface where the prefix for that address
is hosted. The mobile access gateway MUST remove the outer header

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before forwarding the packet. If the mobile access gateway cannot
find the connected interface for that destination address, it MUST
silently drop the packet. For reporting an error in such scenario,
in the form of ICMP control message, the considerations from Generic
Packet Tunneling specification [RFC-2473] apply.

On receiving a packet from a mobile node connected to its access
link, the mobile access gateway MUST ensure that there is an
established binding for that mobile node with its local mobility
anchor before forwarding the packet directly to the destination or
before tunneling the packet to the mobile node's local mobility
anchor.

On receiving a packet from a mobile node connected to its access
link, to a destination that is locally connected, the mobile access
gateway MUST check the configuration variable, EnableMAGLocalRouting,
to ensure the mobile access gateway is allowed to route the packet
directly to the destination. If the mobile access gateway is not
allowed to route the packet directly, it MUST route the packet
through the bi-directional tunnel established between itself and the
mobile's local mobility anchor.

On receiving a packet from the mobile node to any destination i.e.
not directly connected to the mobile access gateway, the packet MUST
be forwarded to the local mobility anchor through the bi-directional
tunnel established between itself and the mobile's local mobility
anchor. However, the packets that are sent with the link-local
source address MUST not be forwarded.

6.11. Interaction with DHCP Relay Agent

If Stateful Address Configuration using DHCP is supported on the link
on which
where the mobile node is attached, the DHCP relay agent [RFC-3315]
needs to be configured on the that access router. link.

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When the mobile node sends a DHCPv6 Request message, the DHCP relay
agent function on the access router MUST link will set the link-address field in
the DHCPv6 message to the mobile node's home network prefix, so as to
provide a prefix hint to the DHCP Server. Since, Server for the address pool
selection.

6.12. Home Network Prefix Renumbering

If the mobile node's home network prefix gets renumbered or becomes
invalid during the middle of a mobility session, the mobile access link is
gateway MUST withdraw the prefix by sending a point-to-point Router Advertisement on
the access link with zero prefix lifetime for the configured mobile node's prefix as home
network prefix. Also, the on-link prefix, local mobility anchor and the normal DHCP relay agent configuration mobile
access gateway MUST delete the routing state for that prefix.
However, the specific details on how the MAG will ensure local mobility anchor
notifies the
prefix hint is set to mobile access gateway about the mobile node's home
network prefix.

6.12. prefix renumbering is outside the scope of this document.

6.13. Mobile Node Detachment Detection and Resource Cleanup

Before sending a Proxy Binding Update message to the local mobility
anchor for extending the lifetime of a currently existing binding of
a mobile node, the mobile access gateway MUST make sure the mobile
node is still attached to the connected link by using some reliable

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method. If the mobile access gateway cannot predictably detect the
presence of the mobile node on the connected link, it MUST NOT
attempt to extend the registration lifetime of the mobile node.
Further, in such scenario, the mobile access gateway MUST SHOULD terminate
the binding of the mobile node by sending a Proxy Binding Update
message to the mobile node's local mobility anchor with lifetime
value set to 0. It MUST also remove any local state such as the
Binding Update List created for that mobile node.

The specific detection mechanism of the loss of a visiting mobile
node on the connected link is specific to the access link between the
mobile node and the mobile access gateway and is outside the scope of
this document. Typically, there are various link-layer specific
events specific to each access technology that the mobile access
gateway can depend on for detecting the node loss. In general, the
mobile access gateway can depend on one or more of the following
methods for the detection presence of the mobile node on the
connected link:

o Link-layer event specific to the access technology

o PPP Session termination event on point-to-point link types

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o IPv6 Neighbor Unreachability Detection event from IPv6 stack

o Notification event from the local mobility anchor

o Absence of data traffic from the mobile node on the link for a
certain duration of time

6.13. Allowing network access to other IPv6 nodes

In some proxy mobile IPv6 deployments, network operators may want to
provision the mobile access gateway to offer network-based mobility
management service only to some visiting mobile nodes and enable just
regular IPv6/IPv4 access to some other nodes attached to that mobile
access gateway. This requires the network to have the control on
when to enable network-based mobility management service to a mobile
node and when to enabled a regular IPv6 access. This specification
does not disallow such configuration.

Upon obtaining the mobile node's profile after a successful access
authentication and after a policy consideration, the mobile access
gateway MUST determine if the network based mobility service should
be offered to that mobile node. If the mobile node is entitled for
such service, then the mobile access gateway must ensure the mobile
node believes it is on its home link, as explained in various
sections of this specification.

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If the mobile node is not entitled for the network-based mobility
management service, as enforced by the policy, the mobile access
gateway MAY choose to offer regular IPv6 access to the mobile node
and hence the normal IPv6 considerations apply. If IPv6 access is
enabled, the mobile node SHOULD be able
certain duration of time

6.14. Allowing network access to obtain any other IPv6 address
using normal nodes

In some proxy mobile IPv6 address configuration mechanisms. The obtained
address must be from a local visitor deployments, network prefix. This
essentially ensures, operators may want to
provision the mobile access gateway functions as any other
access router and does not impact the protocol operation of a mobile
node attempting to use host-based offer network-based mobility
management service when it
attaches only to an some visiting mobile nodes and enable just
regular IPv6/IPv4 access link connected to a some other nodes attached to that mobile
access gateway in gateway. This requires the network to have the control on
when to enable network-based mobility management service to a
proxy mobile
node and when to enable regular IPv6 domain.

7. Mobile Node Operation access. This non-normative section discusses specification does
not disallow such configuration.

Upon obtaining the mobile node's operation in a
Proxy Mobile IPv6 domain.

Once the mobile node enters profile after a Proxy Mobile IPv6 domain and attaches
to an successful access network
authentication and after the access authentication, the network
ensures, a policy consideration, the mobile using any of the address configuration mechanisms
permitted by access
gateway MUST determine if the network for that mobile node, will based mobility service should
be able offered to obtain
an address and move anywhere in that proxy mobile IPv6 domain. From
the perspective of the mobile, the entire proxy mobile IPv6 domain
appears as a single link, the network ensures the mobile believes it
is always on node. If the same link.

The mobile node can be operating in an IPv4-only mode, IPv6-only mode
or in dual IPv4/IPv6 mode. However, the specific details on how the
IPv4 network-based mobility management service is offered to entitled for
such service, then the mobile access gateway must ensure the mobile
node believes it is specified on its home link, as explained in various
sections of this specification.

If the companion document, IPv4 Support mobile node is not entitled for
Proxy Mobile IPv6 [ID-IPV4-PMIP6].

Typically, the configured policy in network-based mobility
management service, as enforced by the network determines if policy, the mobile node is authorized for IPv6, IPv4 or IPv6/IPv4 home address
mobility. If access
gateway MAY choose to offer regular IPv6 access to the configured policy for a mobile node
and hence the normal IPv6 considerations apply. If IPv6 access is for IPv6-
only home address mobility,
enabled, the mobile node will SHOULD be able to obtain
its IPv6 home address, any where in that Proxy Mobile IPv6 domain,
otherwise the address
using normal IPv6 address configuration mechanisms. The obtained
address will must be from a local prefix and not
from a prefix that is topologically anchored at visitor network prefix. This
essentially ensures, the local mobility
anchor mobile access gateway functions as any other
access router and hence does not impact the protocol operation of a mobile will loose that address after
node attempting to use host-based mobility management service when it moves
attaches to an access link connected to a new link.

7.1. Booting up mobile access gateway in a
Proxy Mobile IPv6 Domain

When a domain.

7. Mobile Node Operation

This non-normative section explains the mobile node moves into node's operation in a proxy mobile
Proxy Mobile IPv6 domain and attaches domain.

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to an access link, the mobile node will present its identity, MN-
Identity, to the network as part of the access authentication
procedure.

7.1. Moving into a Proxy Mobile IPv6 Domain

Once the authentication procedure is complete and the a mobile node is authorized enters a Proxy Mobile IPv6 domain and attaches to
an access the network, the network or
specifically the mobile access gateway on the access link will have
detects the mobile node's profile and so it would know attachment of the mobile node's home
network prefix node and completes the permitted address configuration modes. The
mobile node's home network prefix may also be dynamically assigned by binding
registration with the mobile node's local mobility anchor and anchor. If the same may be learnt by
binding update operation is successfully performed, the mobile access gateway.
gateway will create the required state and setup the data path for
the mobile node's data traffic.

If the mobile node is IPv6 enabled, on attaching to the link and
after access authentication, the mobile node link,
it will typically would send a Router Solicitation message. message [RFC-2461]. The
mobile access gateway on the
attached access link will respond to the Router
Solicitation message with a Router Advertisement. The Router
Advertisement will have the mobile node's home network prefix,
default-router address and other address configuration parameters. The address configuration parameters such
as Managed Address Configuration, Stateful Configuration flag values
will typically

If the mobile access gateway on the access link, receives a Router
Solicitation message from the mobile node, before it completed the
signaling with the mobile node's local mobility anchor, the mobile
access gateway may not know the mobile node's home network prefix and
may not be consistent through out that domain for that able to emulate the mobile
node. node's home link on the access
link. In such scenario, the mobile node may notice a slight delay
before it receives a Router Advertisement message.

If the received Router Advertisement has the Managed Address
Configuration flag set, the mobile node, as it would normally do,
will send a DHCPv6 Request and the mobile access gateway [RFC-3315]. The DHCP relay service
enabled on that access link will
ensure, ensure the mobile node gets an address from will obtain
its home network prefix IPv6 address as a lease from the DHCP server. its home network prefix.

If the received Router Advertisement does not have the Managed
Address Configuration flag set and if the mobile node is allowed to
use an autoconfigured address, the mobile node will generate be able to obtain
an IPv6 address using an interface
identifier, identifier generated as per the
Autoconf specification [RFC-2462] or using
privacy extensions as specified in per the Privacy Extensions
specification [RFC-3041].

If the mobile node is IPv4 enabled or IPv4-only enabled, the mobile
node after and if the access authentication, network permits, it
will be able to obtain the IPv4 address configuration for the
connected interface by using DHCPv4. DHCP [RFC-2131]. The details related to
IPv4 support is specified in the companion document [ID-IPV4-PMIP6].

Once the address configuration is complete, the mobile node can
continue to use the obtained this address configuration as long as it is
with attached
to the network that is in the scope of that Proxy Mobile IPv6 domain.

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7.2. Roaming in the Proxy Mobile IPv6 Network Domain

After booting obtaining the address configuration in the Proxy Mobile IPv6 domain and obtaining the
address configuration,
domain, as the mobile node as it roams in the network
between access links, will always detect moves and changes its home network prefix on

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from one mobile access gateway to the link, as other, it can still continue to
use the same address configuration. As long as the attached access
network is in the scope of that Proxy Mobile IPv6 domain. The domain, the mobile
node can continue to use will always detect the same link, where it obtained its IPv4/IPv6 MN-HoA for sending and receiving packets. initial
address configuration. If the mobile node uses performs DHCP for address configuration, operation,
it will always be
able to obtain its MN-HoA using DHCP. the same address as before.

However, the mobile node will always detect a new default-router on
each connected link, but still advertising the mobile node's home
network prefix as the on-link prefix and with the other configuration
parameters consistent with its home link properties.

7.3. IPv6 Host Protocol Parameters

This specification does not require any changes to the mobile node's
IP stack. It assumes the mobile node to be a normal IPv6 IPv4/IPv6 node,
with its protocol operation consistent with the base IPv6
specification [RFC-2460]. All aspects of Neighbor Discovery
Protocol, including Router Discovery, Neighbor Discovery, Address
Configuration procedures will just remain consistent with the base
IPv6 Neighbor Discovery Specification [RFC-2461]. respective
specifications.

However, this specification recommends that the following IPv6
operating parameters on the mobile node be adjusted to the below
recommended values for protocol efficiency and for achieving faster
hand-offs.

Lower Default-Router List Cache Time-out:

As per the base IPv6 specification [RFC-2460], [RFC-2461], each IPv6 host will is
required to maintain certain host data structures including a
Default-Router list. This is the list of on-link routers that have
sent Router Advertisement messages and are eligible to be default
routers on that link. The Router Lifetime field in the received
Router Advertisement defines the life of this entry.

In the case of Proxy Mobile IPv6 scenario, IPv6, when the a mobile node moves from one link
to another, the source address of the received Router Advertisement
messages advertising the mobile's mobile node's home network prefix will be
from a different link-local address and thus making the mobile node
believe that there is a new default-router on the link. It is
important that the mobile node uses the newly learnt default-router
as supposed to the previously learnt known default-router. The mobile node
must update its default-router list with the new default router entry
and must age out the previously learnt default router entry from its
cache, just as specified in Section 6.3.5 of the base IPv6 ND specification [RFC-
2461]. [RFC-2461]. This action is

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critical for minimizing packet losses during a hand off switch.

On detecting a reachability problem, the mobile node will certainly
detect the neighbor or the default-router unreachability loss by performing a the Neighbor
Unreachability Detection procedure, but it is

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mobile node times out the previous default router entry at the
earliest. If a given IPv6 host implementation has the provision to
adjust these flush timers, still conforming to the base IPv6 ND
specification, it is desirable to keep the flush-timers to suit the
above consideration.

However, if

In access network where SEND [RFC-3971] is not deployed, the mobile
access gateway has the ability to may withdraw the previous default-router entry, by
sending a Router Advertisement using the link-local address that of
the previous mobile access gateway and with the Router Lifetime field
set to value 0, then it is
possible to value 0, then this will force the flush of the Previous
Default-Router entry from the mobile node's cache. This certainly
requires some context-
transfer context-transfer mechanisms in place for notifying the link-local link-
local address of the default-router on the previous link to the
mobile access gateway on the new link.

There are other solutions possible for this problem, including the
assignment of a unique link-local address for all the mobile access
gateways access
gateways in a Proxy Mobile IPv6 domain and where SEND [RFC-3971] is
not deployed. In such scenario, the mobile node is not required to
update the default-router entry. However, this is an implementation
choice and has no bearing on the protocol interoperability.
Implementations are free to adopt the best approach that suits their
target deployments.

8. Message Formats

This section defines extensions to the Mobile IPv6 [RFC-3775]
protocol messages.

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8.1. Proxy Binding Update

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|H|L|K|M|R|P| Reserved | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 11: Proxy Binding Update Message

A Binding Update message that is sent by a mobile access gateway to a
local mobility anchor is referred to as the "Proxy Binding Update"
message. A new flag (P) is included in the Binding Update message.
The rest of the Binding Update message format remains the same as
defined in [RFC-3775].

Proxy Registration Flag (P)

A new flag (P) is included in the Binding Update message to indicate
to the local mobility anchor that the Binding Update message is a
proxy registration. The flag MUST be set to the value of 1 for proxy
registrations and MUST be set to 0 for direct registrations sent by a
mobile node.

For descriptions of other fields present in a Proxy Mobile IPv6 domain. In any case, this is an
implementation choice and has no bearing on the protocol
interoperability. Implementations are free message, refer to adopt the best
approach that suits their target deployments.

8. Message Formats

This
section defines extensions to the 6.1.7 [RFC-3775].

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protocol messages.

8.1. September 2007

8.2. Proxy Binding Update Acknowledgment

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # Status |K|R|P|Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|H|L|K|M|R|P| Reserved
| Sequence # | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 9: 12: Proxy Binding Update Acknowledgment Message

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A Binding Update Acknowledgement message that is sent by a local mobility
anchor to a mobile access gateway is referred to as the Proxy "Proxy
Binding Update Acknowledgement" message.

Proxy Registration Flag A new flag (P) is included in the
Binding Acknowledgment message. The rest of the Binding
Acknowledgment message format remains the same as defined in [RFC-
3775].

Proxy Registration Flag (P)

A new flag (P) is set included in the Binding Acknowledgement message to
indicate to that the local mobility anchor that processed the
corresponding Proxy Binding Update is from a mobile access gateway acting
as a message supports proxy mobility agent.
registrations. The flag MUST be is set to only if the value of 1
for proxy registrations and MUST be corresponding Proxy
Binding Update had the Proxy Registration Flag (P) set to 0 for direct registrations
sent by a mobile node when using host-base mobility. value of 1.

For descriptions of other fields present in this message, refer to
the section 6.1.7 6.1.8 [RFC-3775].

8.3. Home Network Prefix Option

A new option, Home Network Prefix Option is defined for using it in
the Proxy Binding Update and Proxy Binding Acknowledgment messages
exchanged between a local mobility anchor and a mobile access
gateway. This option is used for exchanging the mobile node's home
network prefix information.

The Home Network Prefix Option has an alignment requirement of 8n+4.
Its format is as follows:

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8.2. Proxy Binding Acknowledgment September 2007

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status |K|R|P|Reserved Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Length | Sequence # Reserved | Lifetime Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Home Network Prefix +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 10: Proxy Binding Acknowledgment Message

A Binding Acknowledgment message that is sent by

Type
<IANA>

Length

8-bit unsigned integer indicating the local mobility
anchor to length of the mobile access gateway is referred to as "Proxy Binding
Acknowledgement".

Proxy Registration Flag (P)

A new flag (P) is included option
in octets, excluding the Binding Acknowledgement message type and length fields. This field
MUST be set to
indicate that the local mobility anchor that processed the
corresponding Proxy Binding Update message supports Proxy
Registrations. The flag 18.

Reserved

This field is set only if unused for now. The value MUST be initialized
to 0 by the corresponding Proxy
Binding Update had sender and MUST be ignored by the Proxy Registration Flag (P) set to value of 1.
The rest of receiver.

Prefix Length

8-bit unsigned integer indicating the Binding Acknowledgement format remains prefix length of the same, as
defined in [RFC-3775].

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IPv6 June 2007

For descriptions of other fields present prefix contained in this message, refer to the section 6.1.8 of Mobile option.

Home Network Prefix

A sixteen-byte field containing the mobile node's IPv6 specification [RFC3775].

8.3. Home
Network Prefix.

Figure 13: Home Network Prefix Option

8.4. Link-local Address Option

A new option, Home Network Prefix Link-local Address Option is defined for using it in
the Proxy Binding Update and Proxy Binding Acknowledgment messages
exchanged between the a local mobility anchor and the a mobile access
gateway. This option can be is used for exchanging the mobile node's home network
prefix information. link-
local address.

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The home network prefix Option Link-local Address option has an alignment requirement of 8n+4. 8n+6.
Its format is as follows:

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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved | Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Home Network Prefix Link-local Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Type
<IANA>

Length

8-bit unsigned integer indicating the length in octets of the option, option
in octets, excluding the type and length fields. This field
MUST be set to 18.

Reserved

This field is unused for now. The value MUST be initialized
to 0 by the sender and MUST be ignored by the receiver.

Prefix Length

8-bit unsigned integer indicating the prefix length of the
IPv6 prefix contained in the option.

Home Network Prefix 16.

Link-local Address

A sixteen-byte field containing the mobile node's IPv6 Home
Network Prefix. link-local
address.

Figure 11: Home Network Prefix 14: Link-local Address Option

8.4. Time Stamp

8.5. Timestamp Option

A new option, Time Stamp Timestamp Option is defined for use in the Proxy
Binding Update and Acknowledgement messages. This option can be used
in Proxy Binding Update and Proxy Binding Acknowledgement messages.

The Timestamp option has an alignment requirement of 8n+2. Its
format is as follows:

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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Option Type | Option Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Timestamp +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Type
<IANA>

Length

8-bit unsigned integer indicating the length in octets of
the option, excluding the type and length fields. This The value
for this field MUST be set to 8.

Timestamp

A 64-bit time stamp

Figure 12: Time Stamp Option

8.5. Status Codes

This document defines unsigned integer field containing a timestamp. The value
indicates the following new Binding Acknowledgement
status values:

145: Proxy Registration not supported number of seconds since January 1, 1970, 00:00 UTC,
by the local mobility anchor

146: Proxy Registrations from this mobile access gateway not allowed

147: Home Network prefix for using a fixed point format. In this NAI format, the integer number
of seconds is not configured contained in the first 48 bits of the field, and the Home
Network Prefix Option not present in
remaining 16 bits indicate the Proxy Binding Update.

148: Invalid Time Stamp number of 1/64K fractions of a
second.

Figure 15: Timestamp Option in

8.6. Status Values

This document defines the received following new Status values for use in
Proxy Binding Update Acknowledgment message. These values are to be
allocated from the same number space, as defined in Section 6.1.8
[RFC-3775].

Status values less than 128 indicate that the Proxy Binding Update
was processed successfully by the receiving nodes. Values local mobility anchor. Status
values greater than 128 indicate that the Proxy Binding Update was
rejected by the local mobility anchor.

The value allocation for this usage needs to be approved by the IANA

PROXY_REG_NOT_ENABLED:

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and must be updated

Proxy Registration not enabled for the mobile node.

MAG_NOT_AUTHORIZED_FOR_PROXY_REG:

The mobile access gateway is not authorized to send proxy binding.
updates.

NOT_AUTHORIZED_FOR_HOME_NETWORK_PREFIX

The mobile node is not authorized for the requesting home network
prefix.

TIMESTAMP_MISMATCH:

Invalid Timestamp value in the IANA registry. received Proxy Binding Update
message.

MISSING_MN_IDENTIFIER_OPTION:

Missing mobile node identifier in the Proxy Binding Update
message.

9. Protocol Configuration Variables

The mobile access gateway MUST allow the following variables to be
configured by the system management.

EnableMAGLocalrouting

This flag indicates whether or not the mobile access gateway is
allowed to enable local routing of the traffic exchanged between a
visiting mobile node and a corresponding node that is locally
connected to one of the interfaces of the mobile access gateway.
The corresponding node can be another visiting mobile node as
well, or a local fixed node.

The default value for this flag is set to "FALSE", indicating that
the mobile access gateway MUST reverse tunnel all the traffic to
the mobile node's local mobility anchor.

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When the value of this flag is set to "TRUE", the mobile access
gateway MUST route the traffic locally.

This aspect of local routing MAY be defined as policy on a per
mobile basis and when present will take precedence over this flag.

The local mobility anchor MUST allow the following variables to be
configured by the system management.

MinDelayBeforeBCEDelete

This variable specifies the amount of time in milli-seconds the
local mobility anchor MUST wait before it deletes a binding cache
entry of a mobile node, upon receiving a Proxy Binding Update
message from a mobile access gateway with a lifetime value of 0.
During this wait time, if the local mobility anchor receives a
Proxy Binding Update for the same mobile node, identified by its
MN-Identifier, with lifetime value greater than 0, then it must
update the binding cache entry with the accepted binding values.
At the end of this wait-time, if the local mobility anchor did not
receive any valid Proxy Binding Update message, it MUST delete the
binding cache entry for that mobile node.

The default value for this variable is 1000 milli-seconds.

10. IANA Considerations

This document defines a two three new Mobility Header Options, the Home
Network Prefix Option option, Link-local Address option and the Time Stamp Option. Timestamp
option. These options are described in Sections 8.3 8.3, 8.4 and 8.5
respectively. The Type value for these options needs to be assigned
from the same numbering space as allocated for the other mobility
options, as defined in [RFC-3775].

This document also defines new Binding Acknowledgement status values
as described in Section 8.5. 8.6. The status values MUST be assigned from
the same number space used for Binding Acknowledgement status values,
as defined in [RFC-3775].

11. Security Considerations The potential security threats against any general network-based
mobility management protocol are covered in the document, Security
Threats to Network-Based Localized Mobility Management [RFC-4832].
This section analyses those vulnerabilities in the context of Proxy

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Mobile IPv6 protocol solution and covers all aspects around those
identified vulnerabilities.

A compromised mobile access gateway can potentially send Proxy
Binding Update messages on behalf of the mobile nodes that are not
attached to its access link. This threat is similar to an attack on
a typical routing protocol or equivalent to the compromise of an on-
path router. This threat exists in the network today and this
specification does not make this vulnerability any worse than what it
is. However, to eliminate this vulnerability, the local mobility
anchor before accepting Proxy Binding Update message received from a
mobile access gateway, MUST ensure the mobile node is attached to the
mobile access gateway that sent the Proxy Binding Update message.
This can be achieved using out of band mechanisms and the specifics
of how that is achieved is beyond the scope of this document.

This document does not cover the security requirements for
authorizing the mobile node allocated values for the use each of the access link. It is
assumed that there are proper Layer-2/Layer-3 based authentication
procedures, such as EAP, are in place and will ensure the mobile node
is properly identified and authorized before permitting it to access
the network. It is further assumed that the same security mechanism
will ensure the mobile session is not hijacked by malicious nodes on
the access link. these
status values MUST be greater than 128.

11. Security Considerations

The potential security threats against any network-based mobility
management protocol are described in [RFC-4832]. This specification section

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explains how Proxy Mobile IPv6 protocol defends itself against those
threats.

Proxy Mobile IPv6 protocol requires that all the signaling messages messages, Proxy
Binding Update and Proxy Binding Acknowledgement, exchanged between
the mobile access gateway and the local mobility anchor MUST
be authenticated by IPsec [RFC-4301]. The use of IPsec to protect
Mobile IPv6 signaling messages is described in detail in be
protected using IPsec, using the HA-MN
IPsec specification [RFC-3776] and established security association
between them. This essentially eliminates the applicability threats related to the
impersonation of that security
model the mobile access gateway or the local mobility
anchor.

This specification allows a mobile access gateway to Proxy Mobile IPv6 protocol is covered in Section 4.0 send binding
registration messages on behalf of this
document.

As described a mobile node. If proper
authorization checks are not in the base Mobile IPv6 place, a malicious node may be able
to hijack a mobile node's session or may do a denial-of-service
attacks. To prevent this attack, this specification [RFC-3775], both requires the
local mobility anchor to allow only authorized mobile node (in case access gateways
to send binding registration messages on behalf of Proxy Mobile IPv6, its a mobile node.

To eliminate the threats on the interface between the mobile access
gateway)
gateway and the local mobility anchor MUST support mobile node, this specification requires an
established trust between the mobile access gateway and SHOULD use the Encapsulating Security Payload (ESP) header in transport mode mobile
node and
MUST use a non-NULL payload authentication algorithm to provide data
origin authentication, data integrity and optional anti-replay
protection.

The proxy solution allows one device creating a routing state for
some other device at authenticate and authorize the local mobility anchor. It mobile node before it is important
allowed to access the network.

To eliminate the threats related to a compromised mobile access
gateway, this specification recommends that the local mobility anchor has proper authorization services in place
to ensure
before accepting a Proxy Binding Update message for a given mobile
node, to reasonably ensure, using some out of band mechanisms, that
the given mobile node is attached to that mobile access gateway is permitted that
sent the request.

The issues related to be a proxy
for a specific compromised mobile node. If proper security checks are not access gateway in
place, a malicious node may be able to hijack a session or may do a
denial-of-service attacks.

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scenario where the local mobility anchor and the mobile access
gateway in different domains, is outside the scope of this document.
This scenario is beyond the applicability of this document.

12. Acknowledgements

The authors would like to specially thank Julien Laganier, Christian
Vogt, Pete McCann, Brian Haley, Ahmad Muhanna, JinHyeock Choi for
their thorough review of this document.

The authors would also like to thank the Alex Petrescu, Alice Qinxia,
Alper Yegin, Ashutosh Dutta, Behcet Sarikaya, Fred Templing, Genadi
Velev, George Tsirtsis, Gerardo Giaretta, Henrik Levkowetz, Hesham
Soliman, James Kempf, Jari Arkko, Jean-Michel Combes, John Zhao,

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Jong-Hyouk Lee, Jonne Soininen, Jouni Korhonen, Kilian Weniger, Alex Petrescu, Marco
Liebsch, Mohamed Khalil, Fred Templing, Nishida Katsutoshi, James Kempf, Vidya Narayanan, Henrik Levkowetz, Phil Roberts, Jari Arkko, Ashutosh Dutta, Hesham Soliman, Behcet Sarikaya,
George Tsirtsis Ryuji
Wakikawa, Sangjin Jeong, Suresh Krishnan, Vidya Narayanan, Youn-Hee
Han and many others for their passionate discussions in the working
group mailing list on the topic of localized mobility management
solutions. These discussions stimulated much of the thinking and
shaped the draft to the current form. We acknowledge that !

The authors would also like to thank Ole Troan, Akiko Hattori, Parviz
Yegani, Mark Grayson, Michael Hammer, Vojislav Vucetic, Jay Iyer and
Tim Stammers for their input on this document.

13. References

13.1. Normative References

[RFC-1305]

[RFC-2030] Mills, D., "Network "Simple Network Time Protocol (Version 3)
Specification, Implementation", RFC 1305, March 1992.

[RFC-2460] Deering, S. and R. Hinden, "Internet Protocol, (SNTP) Version 6
(IPv6) Specification", 4
for IPv4, IPv6 and OSI", RFC 2460, December 1998. 2030, October 1996.

[RFC-2131] Droms, R., "Dynamic Host Configuration Protocol", RFC
2131, March 1997.

[RFC-2461] Narten, T., Nordmark, E. and W. Simpson, "Neighbor
Discovery for IP Version 6 (IPv6)", RFC 2461, December 1998.

[RFC-2462] Thompson, S., Narten, T., "IPv6 Stateless Address
Autoconfiguration", RFC 2462, December 1998.

[RFC-2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
IPv6 Specification", RFC 2473, December 1998.

[RFC-3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C. and
M.Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
RFC 3315, July 2003.

[RFC-3775] Johnson, D., Perkins, C., Arkko, J., "Mobility Support in
IPv6", RFC 3775, June 2004.

[RFC-3776] Arkko, J., Devarapalli, V., and F. Dupont, "Using IPsec to

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[RFC-3776] Arkko, J., Devarapalli, V., and F. Dupont, "Using IPsec to
Protect Mobile IPv6 Signaling Between Mobile Nodes and Home Agents",
RFC 3776, June 2004.

[RFC4282] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The
Network Access Identifier", RFC 4282, November 2005.

[RFC-4283] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K.
Chowdhury, "Mobile Node Identifier Option for Mobile IPv6", RFC 4283,

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November 2005.

[RFC-4301] Kent, S. and Atkinson, R., "Security Architecture for the
Internet Protocol", RFC 4301, December 2005.

[RFC-4303] Kent, S. "IP Encapsulating Security Protocol (ESP)", RFC
4303, December 2005.

[RFC-4306] Kaufman, C, et al, "Internet Key Exchange (IKEv2)
Protocol", RFC 4306, December 2005.

[RFC-4830] Kempf, J., Leung, K., Roberts, P., Nishida, K., Giaretta,
G., Liebsch, M., "Problem Statement for Network-based Localized
Mobility Management", September 2006.

[RFC-4831] Kempf, J., Leung, K., Roberts, P., Nishida, K., Giaretta,
G., Liebsch, M., "Goals for Network-based Localized Mobility
Management", October 2006.

[RFC-4832] Vogt, C., Kempf, J., "Security Threats to Network-Based
Localized Mobility Management", September 2006.

[ID-IPV4-PMIP6] Wakikawa, R.

[RFC-4877] Devarapalli, V. and Gundavelli, S., "IPv4 Support for
Proxy Mobile IPv6", draft-ietf-netlmm-pmip6-ipv4-support-00.txt, May
2007.

[ID-DSMIP6] Soliman, H. et al, Dupont, F., "Mobile IPv6 support for dual stack
Hosts Operation
with IKEv2 and Routers (DSMIPv6)",
draft-ietf-mip6-nemo-v4traversal-03.txt, October 2006. the revised IPsec Architecture", RFC 4877, April 2007.

13.2. Informative References

[RFC-1332] McGregor, G., "The PPP Internet Protocol Control Protocol
(IPCP)", RFC 1332, May 1992.

[RFC-1661] Simpson, W., Ed., "The Point-To-Point Protocol (PPP)", STD
51, RFC 1661, July 1994.

[RFC-2472] Haskin, D. and Allen, E., "IP version 6 over PPP", RFC
2472, December 1998.

[RFC-2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998.

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[RFC-3041] Narten, T. and Draves, R., "Privacy Extensions for
Stateless Address Autoconfiguration in IPv6", RFC 3041, January 2001.

[RFC-3344] Perkins, C., "IP Mobility Support for IPv4", RFC 3344,
August 2002.

[RFC-3756] Nikander, P., Kempf, J., and E. Nordmark, "IPv6 Neighbor
Discovery (ND) Trust Models and Threats", RFC 3756, May 2004.

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[ID-IPV4-PMIP6] Wakikawa, R. and Gundavelli, S., "IPv4 Support for
Proxy Mobile IPv6", draft-ietf-netlmm-pmip6-ipv4-support-00.txt, May
2007.

[ID-DNAV6] Kempf, J., et al "Detecting Network Attachment in IPv6
Networks (DNAv6)", draft-ietf-dna-protocol-03.txt, October 2006.

[ID-MIP6-IKEV2] Devarapalli, V.

[ID-MN-AR-INTERFACE] Laganier, J. and Dupont, F., Narayanan, S., "Network-based
Localized Mobility Management Interface between Mobile Node and
Mobility Access Gateway", draft-ietf-netlmm-mn-ar-if-02.txt, May
2007.

[ID-DSMIP6] Soliman, H. et al, "Mobile IPv6
Operation with IKEv2 support for dual stack
Hosts and the revised IPsec Architecture",
draft-ietf-mip6-ikev2-ipsec-08.txt, December Routers (DSMIPv6)",
draft-ietf-mip6-nemo-v4traversal-03.txt, October 2006.

Appendix A. Proxy Mobile IPv6 interactions with AAA Infrastructure

Every mobile node that roams in a proxy Mobile IPv6 domain, would
typically be identified by an identifier, MN-Identifier, and that
identifier will have an associated policy profile that identifies the
mobile node's home network prefix, permitted address configuration
modes, roaming policy and other parameters that are essential for
providing network-based mobility service. This information is
typically configured in AAA. It is possible the home network prefix
is dynamically allocated for the mobile node when it boots up for the
first time in the network, or it could be a statically configured
value on per mobile node basis. However, for all practical purposes,
the network entities in the proxy Mobile IPv6 domain, while serving a
mobile node will have access to this profile and these entities can
query this information using RADIUS/DIAMETER protocols.

Appendix B. Supporting Shared-Prefix Model using DHCPv6

For supporting shared-prefix model, i.e, if multiple mobile nodes are
configured with a common IPv6 network prefix, as in Mobile IPv6
specification,

This specification supports Per-MN-Prefix model. However, it is
possible to support that configuration Shared-Prefix model under the following guidelines:
guidelines.

The mobile node is allowed to use stateful address configuration
using DHCPv6 for obtaining its address configuration. The mobile
nodes
node is not allowed to use any of the stateless autoconfiguration
techniques. The permitted address configuration models for the

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mobile node on the access link can be enforced by the mobile access

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gateway, by setting the relevant flags in the Router Advertisements,
as per ND Specification, [RFC-2461].

The Home Network Prefix Option option that is sent by the mobile access
gateway in the Proxy Binding Update message, must contain the 128-bit
host address that the mobile node obtained via DHCPv6.

Routing state at the mobile access gateway:

For all IPv6 traffic from the source MN-HoA::/128 to
_ANY_DESTINATION_, route via tunnel0, next-hop LMAA, where tunnel0 is
the MAG to LMA tunnel.

Routing state at the local mobility anchor:

For all IPv6 traffic to destination MN-HoA::/128, route via tunnel0,
next-hop Proxy-CoA, where tunnel0 is the LMA to MAG tunnel.

Authors' Addresses

Sri Gundavelli
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA

Email: sgundave@cisco.com

Kent Leung
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA

Email: kleung@cisco.com

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Vijay Devarapalli
Azaire Networks
4800 Great America Pkwy
Santa Clara, CA 95054
USA

Email: vijay.devarapalli@azairenet.com

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Kuntal Chowdhury
Starent Networks
30 International Place
Tewksbury, MA

Email: kchowdhury@starentnetworks.com

Basavaraj Patil
Nokia Siemens Networks
6000 Connection Drive
Irving, TX 75039
USA

Email: basavaraj.patil@nsn.com

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Full Copyright Statement

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contained in BCP 78, and except as set forth therein, the authors
retain all their rights.

This document and the information contained herein are provided on an
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Acknowledgment

Funding for the RFC Editor function is provided by the IETF
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