One document matched: draft-calhoun-diameter-mobileip-01.txt
Differences from draft-calhoun-diameter-mobileip-00.txt
INTERNET DRAFT Pat R. Calhoun
Category: Standards Track Charles E. Perkins
Title: draft-calhoun-diameter-mobileip-01.txt Sun Laboratories, Inc.
Date: November 1998
DIAMETER Mobile IP Extensions
Status of this Memo
Comments should be submitted to the diameter@ipass.com mailing list.
Distribution of this memo is unlimited.
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute
working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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To view the entire list of current Internet-Drafts, please check the
``1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow
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Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu (US West Coast).
Abstract
DIAMETER is an Authentication, Authorization and Accounting (AAA)
Policy Protocol that is used between two entities for various
services. This document defines an extension that allow a DIAMETER
Client to request authentication and receive autorization information
for a Mobile IP Mobile Node.
Table of Contents
1.0 Introduction
1.1 Specification of Requirements
2.0 Command Codes
2.1 AA-Mobile-Node-Request (AMR)
2.2 AA-Mobile-Node-Answer (AMA)
2.3 Home-Agent-MIP-Request
2.4 Home-Agent-MIP-Answer
3.0 DIAMETER AVPs
3.1 MIP-Registration-Request
3.2 MIP-Registration-Reply
3.3 MN-FA-Challenge
3.4 MN-FA-Response
3.5 MN-FA-SPI
3.6 MN-to-FA-Key
3.7 FA-to-MN-Key
3.8 FA-HA-SPI
3.9 FA-to-HA-Key
3.10 HA-to-FA-Key
3.11 MN-HA-SPI
3.12 MN-to-HA-Key
3.13 HA-to-MN-Key
3.14 Mobile-Node-Address
3.15 Home-Agent-Address
3.16 Previous-FA-NAI
3.17 Foreign-Home-Agent-Available
4.0 Protocol Definition
4.1 Inter-Domain Mobile IP
4.2 Allocation of Home Agent in Foreign Network
5.0 References
6.0 Authors' Addresses
1.0 Introduction
The Mobile IP [4] protocol defines a method that allows a Mobile Node
to change its point of attachment to the Internet without service
disruption. The protocol requires that all Mobility Agents share a
pre-existing security association, which leads to scaling and
configuration problems. Mobile IP also does not mention how Mobility
Agents account for services rendered, which does not make it an
attractive protocol for use by service providers.
This document specifies extensions to DIAMETER that allow cross-
domain authentication and authorization, assignment of Mobile Node
Home Addresses, assignment of Home Agent, as well as Key Distribution
to allow the Mobile IP network to scale in a large network of service
providers.
The dynamic assignment of Mobile Node and Home Agent addresses are
useful for Service Providers wishing to provide Mobile IP services
for mobile nodes.
The DIAMETER Accounting extension [x] will be used to collect
accounting information.
Small modifications to the Mobile IP protocol [4], which already
exists in the TEP protocol [8], to allow a Mobile Node to identify
itself using an NAI [6] in addition to an IP address. The use of the
Network Access Identifier (NAI) [6] is consistent with the current
roaming model which makes use of DIAMETER proxying [7].
The Extension number for this draft is four (4). This value is used
in the Extension-Id Attribute value Pair (AVP) as defined in [1].
1.1 Specification of Requirements
In this document, several words are used to signify the requirements
of the specification. These words are often capitalized.
MUST This word, or the adjective "required", means that the
definition is an absolute requirement of the
specification.
MUST NOT This phrase means that the definition is an absolute
prohibition of the specification.
SHOULD This word, or the adjective "recommended", means that
there may exist valid reasons in particular circumstances
to ignore this item, but the full implications must be
understood and carefully weighed before choosing a
different course.
MAY This word, or the adjective "optional", means that this
item is one of an allowed set of alternatives. An
implementation which does not include this option MUST
be prepared to interoperate with another implementation
which does include the option.
2.0 Command Codes
This section will define the Commands [1] for DIAMETER
implementations supporting the Mobile IP extension.
Command Name Command Code
-----------------------------------
AA-Mobile-Node-Request 306
AA-Mobile-Node-Answer 307
Home-Agent-MIP-Request 308
Home-Agent-MIP-Answer 309
2.1 AA-Mobile-Node-Request (AMR)
Description
The AA-Mobile-Node-Request is sent by a Foreign Agent acting as a
DIAMETER client to a server to request authentication and
authorization of a Mobile Node.
The AA-Mobile-Node-Request message MUST include the MIP-
Registration-Request, User-Name, MN-FA-Challenge, MN-FA-Response
AVP as well as the Session-ID AVPs.
The Mobile-Node-Address AVP contains the the Home Address found in
the Mobile Node's Registration Request. The Home-Agent-Address AVP
contains the Home Address found in the Registration Request. If
the Home Address is zero, it indicates that the Mobile Node is
requesting that an address be allocated to it.
The User-Name AVP contains the NAI found in the Mobile IP
Registration Request's Mobile-Node-NAI Extension.
If the Previous-FA-NAI AVP is found in the request, the DIAMETER
Client is requesting that the Server return the Session Key that
was assigned to the previous Foreign Agent for use with the Mobile
Node. The Session Key is identified through the use of the
Mobile-Foreign-SPI AVP.
Message Format
<AA-Mobile-Node-Request> ::= <DIAMETER Header>
<AA-Mobile-Node-Request Command AVP>
<Session-ID AVP>
<User-Name AVP>
<MIP-Registration-Request AVP>
<MN-FA-Challenge AVP>
<MN-FA-Response AVP>
<Mobile-Node-Address AVP>
<Home-Agent-Address AVP>
[<Previous-FA-NAI AVP>]
[<MN-FA-SPI AVP>]
<Timestamp AVP>
<Initialization-Vector AVP>
{<Integrity-Check-Vector AVP> ||
<Digital-Signature AVP> }
AVP Format
The AA-Mobile-Node-Request Command AVP format is shown below. The
fields are transmitted from left to right.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Command Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AVP Code
256 DIAMETER-Command
AVP Length
The length of this AVP MUST be at exactly 12.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Command Code
The Command Code field MUST be set to 306 (AA-Mobile-Node-
Request).
2.2 AA-Mobile-Node-Answer (AMA)
Description
The AA-Mobile-Node-Answer is sent by the DIAMETER Server to the
client in response to the AA-Mobile-Node-Request message. The
message MUST include the Session-Id, Result-Code, MIP-
Registration-Reply as well as the various key and SPI AVPs (see
section 3.0) and MAY include the Home-Agent-Address and Mobile-
Node-Address AVPs.
The Home-Agent-Address AVP contains the Home Agent assigned to the
Mobile Node. If the AVP contains a zero address, it is a request
to allocate a Home Agent locally.
The Home-Agent-Address AVP contains the IP Address assigned to the
Mobile Node. If this AVP contains a zero address, it is a request
to allocate a Home Address for the Mobile Node.
The following error codes are defined for this message for use in
the Error-Code AVP [1]:
DIAMETER_ERROR_UNKNOWN_DOMAIN 1
This error code is used to indicate to the initiator of the
request that the requested domain is unknown and cannot be
resolved.
DIAMETER_ERROR_USER_UNKNOWN 2
This error code is used to indicate to the initiator that
the username request is not valid.
DIAMETER_ERROR_BAD_PASSWORD 3
This error code indicates that the password provided is
invalid.
DIAMETER_ERROR_CANNOT_AUTHORIZE 4
This error code is used to indicate that the user cannot be
authorized due to the fact that the user has expended local
resources. This could be a result that the server believes
that the user has already spent the number of credits in
his/her account, etc.
Message Format
<AA-Mobile-Node-Answer> ::= <DIAMETER Header>
<AA-Mobile-Node-Answer Command AVP>
<Session-Id AVP>
<Result-Code AVP>
[<Error-Code AVP>]
<MIP-Registration-Reply AVP>
<MN-FA-SPI AVP>
<FA-to-MN-Key AVP>
<FA-HA-SPI AVP>
<FA-to-HA-Key AVP>
<Home-Agent-Address AVP>
<Mobile-Node-Address AVP>
<Session-Timeout AVP>
<Timestamp AVP>
<Initialization-Vector AVP>
{<Integrity-Check-Vector AVP> ||
<Digital-Signature AVP> }
AVP Format
The AA-Mobile-Node-Answer Command AVP format is shown below. The
fields are transmitted from left to right.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Command Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AVP Code
256 DIAMETER-Command
AVP Length
The length of this AVP MUST be at exactly 12.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Command Code
The Command Code field MUST be set to 307 (AA-Mobile-Node-
Answer).
2.3 Home-Agent-MIP-Request (HAR)
Description
The Home-Agent-MIP-Request is sent by the home DIAMETER server to
the Home Agent overseeing the Mobile Node to process the Mobile IP
Registration Request.
The Home-Agent-MIP-Request message MUST include the MIP-
Registration-Request, User-Name, Session-ID as well as the SPI and
key AVPs (see section 3.0) to be used by the Mobile Node and the
Home Agent.
If the Mobile-Node-Address AVP is set to a zero Address, it is a
request to the Home Agent to allocate a Home Address to the Mobile
Node.
Message Format
<Home-Agent-MIP-Request> ::= <DIAMETER Header>
<Home-Agent-MIP-Request Command AVP>
<Session-Id AVP>
<User-Name AVP>
<MIP-Registration-Request AVP>
<MN-HA-SPI AVP>
<HA-to-MN-Key AVP>
<MN-to-HA-Key AVP>
<FA-HA-SPI AVP>
<HA-to-FA-Key AVP>
<MN-FA-SPI AVP>
<MN-to-FA-Key AVP>
<Home-Agent-Address AVP>
<Mobile-Node-Address AVP>
<Session-Timeout AVP>
<Timestamp AVP>
<Initialization-Vector AVP>
{<Integrity-Check-Vector AVP> ||
<Digital-Signature AVP> }
AVP Format
The Home-Agent-MIP-Request Command AVP format is shown below. The
fields are transmitted from left to right.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Command Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AVP Code
256 DIAMETER-Command
AVP Length
The length of this AVP MUST be at exactly 12.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Command Code
The Command Code field MUST be set to 308 (Home-Agent-MIP-
Request).
2.4 Home-Agent-MIP-Answer (HAA)
Description
The Home-Agent-MIP-Answer is sent by the Home Agent to the home
DIAMETER Server in response to the Home-Agent-MIP-Request. The
message MUST include the Session-Id, Result-Code, MIP-
Registration-Reply and the Mobile-Node-Address.
The following error codes are defined for this message for use in
the Error-Code AVP [1]:
DIAMETER_ERROR_BAD_KEY 1
This error code is used by the Home Agent to indicate to the
local DIAMETER Server that the key generated is invalid.
DIAMETER_ERROR_BAD_HOME_ADDRESS 2
This error code is used by the Home Agent to indicate that
the Home Address chosen by the Mobile Node or assigned by
the local DIAMETER server is unavailable.
DIAMETER_ERROR_TOO_BUSY 3
This error code is used by the Home Agent to inform the
DIAMETER Server that it cannot handle an extra Mobile Node.
Upon receiving this error the DIAMETER Server can try to use
an alternate Home Agent if one is available.
DIAMETER_ERROR_MIP_REPLY_FAILURE 4
This error code is used by the Home Agent to inform the
DIAMETER Server that the Registration Request failed.
Message Format
<Home-Agent-MIP-Answer> ::= <DIAMETER Header>
<Home-Agent-MIP-Answer Command AVP>
<Session-Id AVP>
<Result-Code AVP>
[<Error-Code AVP>]
<MIP-Registration-Reply AVP>
<Mobile-Node-Address AVP>
<Home-Agent-Address AVP>
<Timestamp AVP>
<Initialization-Vector AVP>
{<Integrity-Check-Vector AVP> ||
<Digital-Signature AVP> }
AVP Format
The Home-Agent-MIP-Answer Command AVP format is shown below. The
fields are transmitted from left to right.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Command Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AVP Code
256 DIAMETER-Command
AVP Length
The length of this AVP MUST be at exactly 12.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Command Code
The Command Code field MUST be set to 309 (Home-Agent-MIP-
Answer).
3.0 DIAMETER AVPs
This section will define the mandatory AVPs which MUST be supported
by all DIAMETER implementations supporting this extension. The
following AVPs are defined in this document:
Attribute Name Attribute Code
-----------------------------------
MIP-Registration-Request 320
MIP-Registration-Reply 321
MN-FA-Challenge 322
MN-FA-Response 323
MN-FA-SPI 324
MN-to-FA-Key 325
FA-to-MN-Key 326
FA-HA-SPI 327
FA-to-HA-Key 328
HA-to-FA-Key 329
MN-HA-SPI 330
MN-to-HA-Key 331
HA-to-MN-Key 332
Mobile-Node-Address 333
Home-Agent-Address 334
Previous-FA-NAI 335
3.1 MIP-Registration-Request
Description
This AVP is used to carry the Mobile IP Registration Request [4]
sent by the Mobile Node to the Foreign Agent within a DIAMETER
message.
AVP Format
A summary of the MIP-Registration-Request AVP format is shown
below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data ...
+-+-+-+-+-+-+-+-+
Type
320 MIP-Registration-Request
AVP Length
The length of this attribute MUST be at least 9.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Data
The data field contains the Mobile IP Registration Request.
3.2 MIP-Registration-Reply
Description
This AVP is used to carry the Mobile IP Registration Reply [4]
sent by the Home Agent to the Foreign Agent within a DIAMETER
message.
AVP Format
A summary of the MIP-Registration-Reply AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data ...
+-+-+-+-+-+-+-+-+
AVP Code
321 MIP-Registration-Reply
AVP Length
The length of this attribute MUST be at least 9.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Data
The data field contains the Mobile IP Registration Reply.
3.3 MN-FA-Challenge
Description
The Challenge field consists of a 32 bit NTP timstamp followed by
a random value of at least 32 bits. The random value SHOULD be at
least 96 bits in length [5].
AVP Format
A summary of the MN-FA-Challenge AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data ...
+-+-+-+-+-+-+-+-+
AVP Code
322 MN-FA-Challenge
AVP Length
The length of this attribute MUST be at least 16.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Data
The data field contains the Foreign Agent's Challenge to the
Mobile Node.
3.4 MN-FA-Response
Description
This AVP contains the Response generated by the Mobile Node as
defined in the Mobile-Node Response extension [5]. The value is
the result of the Challenge presented by the Foreign Agent hashed
using the secret the Mobile Node shares with its Home DIAMETER
Server.
AVP Format
A summary of the MN-FA-Response AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data ...
+-+-+-+-+-+-+-+-+
AVP Code
323 MN-FA-Response
AVP Length
The length of this attribute MUST be at least 9.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Data
The data field contains the Mobile Node's Challenge Response.
3.5 MN-FA-SPI
Description
The MN-FA-SPI is sent in both the Home-Agent-MIP-Request as well
as the AA-Mobile-Node-Answer messages and contains the SPI value
associated with the key generated by the home DIAMETER Server for
use between the Foreign Agent and the Mobile Node (MN-to-FA-Key,
FA-to-MN-Key).
AVP Format
A summary of the MN-FA-SPI AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SPI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AVP Code
324 MN-FA-SPI
AVP Length
The length of this attribute MUST be 12.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Integer32
The Integer32 field contains the SPI value associated with the
key shared between the Mobile Node and the Foreign Agent.
3.6 MN-to-FA-Key
Description
This AVP contains the Key generated by the home DIAMETER Server
that must be used by the Mobile Node when computing the Mobile-
Foreign Authentication extension in the Mobile IP Registration
Request [4].
AVP Format
A summary of the MN-to-FA-Key AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data ...
+-+-+-+-+-+-+-+-+
AVP Code
325 MN-to-FA-Key
AVP Length
The length of this attribute MUST be at least 9.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Data
The data field contains the encrypted key to be used by the
Mobile Node when generating the Mobile IP Mobile-Foreign-
Authentication-Extension.
3.7 FA-to-MN-Key
Description
This AVP contains the Key generated by the home DIAMETER Server
that must be used by the Foreign Agent when computing the Mobile-
Foreign- Authentication extension in the Mobile IP Registration
Reply [4].
AVP Format
A summary of the FA-to-MN-Key AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data ...
+-+-+-+-+-+-+-+-+
AVP Code
326 FA-to-MN-Key
AVP Length
The length of this attribute MUST be at least 9.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Data
The data field contains the encrypted key to be used by the
Foreign Agent when generating the Mobile IP Mobile-Foreign-
Authentication-Extension.
3.8 FA-HA-SPI
Description
The FA-HA-SPI is sent in both the Home-Agent-MIP-Request as well
as the AA-Mobile-Node-Answer messages and contains the SPI value
associated with the key generated by the home DIAMETER Server for
use between the Foreign Agent and the Home Agent (FA-to-HA-Key,
HA-to-FA-Key).
AVP Format
A summary of the FA-HA-SPI AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SPI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AVP Code
327 FA-HA-SPI
AVP Length
The length of this attribute MUST be 12.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
SPI
The SPI field contains the SPI value associated with the key
shared between the Foreign Agent and the Home Agent.
3.9 FA-to-HA-Key
Description
This AVP contains the Key generated by the home DIAMETER Server
that must be used by the Foreign Agent when computing the
Foreign-Home Authentication extension in the Mobile IP
Registration Request [4].
AVP Format
A summary of the FA-to-HA-Key AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data ...
+-+-+-+-+-+-+-+-+
AVP Code
328 FA-to-HA-Key
AVP Length
The length of this attribute MUST be at least 9.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Data
The data field contains the encrypted key to be used by the
Foreign Agent when generating the Mobile IP Foreign-Home-
Authentication-Extension.
3.10 HA-to-FA-Key
Description
This AVP contains the Key generated by the home DIAMETER Server
that must be used by the Home Agent when computing the Foreign-
Home Authentication extension in the Mobile IP Registration Reply
[4].
AVP Format
A summary of the HA-to-FA-Key AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data ...
+-+-+-+-+-+-+-+-+
AVP Code
329 HA-to-FA-Key
AVP Length
The length of this attribute MUST be at least 9.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Data
The data field contains the encrypted key to be used by the
Home Agent when generating the Mobile IP Foreign-Home-
Authentication-Extension.
3.11 MN-HA-SPI
Description
The MN-HA-SPI is sent in both the Home-Agent-MIP-Request as well
as the AA-Mobile-Node-Answer messages and contains the SPI value
associated with the key generated by the home DIAMETER Server for
use between the Mobile Node and the Home Agent (MN-to-HA-Key, HA-
to-MN-Key).
AVP Format
A summary of the MN-HA-SPI AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SPI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AVP Code
330 MN-HA-SPI
AVP Length
The length of this attribute MUST be 12.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Integer32
The Integer32 field contains the SPI value associated with the
Session Key shared between the Mobile Node and the Home Agent.
3.12 MN-to-HA-Key
Description
This AVP contains the Key generated by the home DIAMETER Server
that must be used by the Mobile Node when computing the Mobile-
Home Authentication extension in the Mobile IP Registration
Request [4].
AVP Format
A summary of the MN-to-HA-Key AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data ...
+-+-+-+-+-+-+-+-+
AVP Code
331 MN-to-HA-Key
AVP Length
The length of this attribute MUST be at least 9.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Data
The data field contains the encrypted key to be used by the
Mobile Node when generating the Mobile IP Mobile-Home-
Authentication-Extension.
3.13 HA-to-MN-Key
Description
This AVP contains the Key generated by the home DIAMETER Server
that must be used by the Home Agent when computing the Mobile-Home
Authentication extension in the Mobile IP Registration Reply [4].
AVP Format
A summary of the HA-to-MN-Key AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data ...
+-+-+-+-+-+-+-+-+
AVP Code
332 HA-to-MN-Key
AVP Length
The length of this attribute MUST be at least 9.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Data
The data field contains the encrypted key to be used by the
Home Agent when generating the Mobile IP Mobile-Home-
Authentication-Extension.
3.14 Mobile-Node-Address
Description
The Mobile-Node-Address AVP contains the Mobile Node's Home
Address. When this AVP has a NULL Address (0.0.0.0), it is a
request that a Home Address be allocated to the Mobile Node.
AVP Format
A summary of the Mobile-Node-Address AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AVP Code
333 Mobile-Node-Address
AVP Length
The length of this attribute MUST be 12.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Address
The Address field contains the IP address assigned to the
Mobile Node, or 0.0.0.0 if one is requested.
3.15 Home-Agent-Address
Description
The Home-Agent-Addess AVP contains the Mobile Node's Home Agent
Address. When this AVP has a NULL address (0.0.0.0), it is a
request that a Home Agent be allocated to the Mobile Node.
AVP Format
A summary of the Home-Agent-Address AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AVP Code
334 Home-Agent-Address
AVP Length
The length of this attribute MUST be 12.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Address
The Address field contains the Home Agent address assigned to
the Mobile Node. If the address is set to 0.0.0.0, the Mobile
Node is requesting that a Home Agent be allocated either in the
foreign network or in its home network. If the address is set
to 255.255.255.255 the Mobile Node is requesting that the Home
Agent be allocated only within its home network.
3.16 Previous-FA-NAI
Description
The Previous-FA-NAI AVP contains the Network Access Identifier of
the Mobile Node's old Foreign Agent. The Mobile Node will include
this information in the Registration Request when it moves it
point of attachment to a new foreign agent under the same
administrative domain as the old FA (identified by the domain part
of the NAI).
When this AVP is present in the AA-Mobile-Node-Request, it
indicates that the local DIAMETER Server overseeing the Foreign
Agent should attempt to return the session key that was previously
allocated to the old Foreign Agent for the Mobile Node. The
session key is identified through the use of the MN-FA-SPI AVP,
which MUST be present if this extension is present.
This allows the Mobile Node to move from one Foreign Agent to
another within the same administrative domain without having to
send the request back to the Mobile Node's Home DIAMETER Server.
AVP Format
A summary of the Previous-FA-NAI AVP format is shown below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| String ...
+-+-+-+-+-+-+-+-+
AVP Code
335 Previous-FA-NAI
AVP Length
The length of this attribute MUST be at least 9.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
String
The String field contains the Mobile Node's old Foreign Agent's
NAI.
3.167 Foreign-Home-Agent-Available
Description
The Foreign-Home-Agent-Available AVP is added by the AAAF owned by
the same adminitrative domain as the Foreign Agent if it is
willing and able to allocate a Home Agent within the Foreign
network for the Mobile Node.
If this extension is present in the AMR and the Home-Agent-Address
AVP is set to 0.0.0.0, the AAAH MAY allow the AAAF to assign a
Home Agent for the Mobile Node. This is done by including the
Home-Agent-Address AVP with a value of 0.0.0.0 in the AMR.
AVP Format
A summary of the Foreign-Home-Agent-Available AVP format is shown
below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AVP Length | Reserved |P|T|V|E|H|M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Integer32 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AVP Code
335 Foreign-Home-Agent-Available
AVP Length
The length of this attribute MUST be at least 9.
AVP Flags
The 'M' bit MUST be set. The 'H' and 'E' MAY be set depending
upon the security model used. The 'V', 'T' and the 'P' bits
MUST NOT be set.
Integer32
The Integer32 field MUST be set to 1 to inform the AAAH that
the AAAF is able and willing to allocate a Home Agent for the
Mobile Node.
4.0 Protocol Definition
This section will outline how the DIAMETER Mobile IP Extension can be
used.
4.1 Inter-Domain Mobile IP
The following diagram is an example of an inter-domain Mobile IP
network.
ISP Home Network
+--------+ +--------+
| | AMR/A | |
| AAAF |<--------------->| AAAH |
| server | server-server | server |
+--------+ communication +--------+
/ /|\ /|\
/AMR/A | client-server | HAR/A
/ | communication |
|/_ \|/ \|/
+---------+ +---------+ +---------+
| Foreign | | Foreign | | Home |
| Agent | | Agent | | Agent |
+---------+ +---------+ +---------+
/|\
| Mobile IP
|
\|/
+--------+
| Mobile |
| Node |
+--------+
The AA-Mobile-Node-Request (AMR) is generated by the Foreign Agent
and includes the AVPs defined in section 2.1. The Mobile-Node-Address
AVP's value is copied from the Registration Request's Home Address
field. The Home-Agent-Address AVP's value is copied from the
Registration Request's Home Agent field. The value of the User-Name
AVP is taken from the Mobile-Node-NAI extension as described in [8].
The request is then forwarded to the Foreign Agent's local DIAMETER
server, known as the AAA-Foreign, or AAAF.
When the AAAF receives the message, it uses the User-Name AVP [1] to
determine whether authentication and authorization can be handled
locally. The User-Name format is consistent with the NAI described in
[6] and the user's domain is used to determine the Mobile Node's home
DIAMETER Server (or AAAH). In the example below, the request cannot
be processed by the AAAF, therefore the request is proxied [9] to the
AAAH. Note that this exchange is only required when the Mobile Node
attempts to gain service with a new Foreign Agent, or if the keys
previously distributed expire.
Mobile Node Foreign Agent AAAF AAAH Home Agent
----------- ------------- ------------ ---------- ----------
<-------Challenge
Reg-Req(Response)->
AMR------------->
AMR------------>
HAR----------->
<----------HAA
<-----------AMA
<------------AMA
<-------Reg-Reply
The AAAH must first authenticate the user by validating the MN-FA-
Challenge which contains a timestamp, which is described in [5]. If
the timestamp information is valid, the AAAH uses the security
association shared between the itself and the Mobile Node in order to
validate the MN-FA-Response. If the response is invalid, the AAAH
returns the AA-Mobile-Node-Answer (AMA, see section 2.2) with a
Result-Code set to the appropriate value.
If the Mobile Node was successfully authenticated, the AAAH checks
whether the Home-Agent-Address AVP specified a Home Agent. If one was
specified, the AAAH must validate the address to ensure that it is a
known Home Agent. If no Home Agent was specified the AAAH SHOULD
allocate one on behalf of the Mobile Node. This can be done in a
variety of ways, including using a load balancing algorithm in order
to keep the load on all Home Agents equal. The actual algorithm used
and the method of discovering the Home Agents is outside of this
specification, but the method proposed in [4] can be used.
If the AMR's Mobile-Node-Address AVP did not specify an address, the
AAAH has the option of assigning an address for the Mobile Node, or
it can leave this up to the Home Agent. This is purely a local policy
decision.
The AAAH then proceeds to generate three short-lived session keys;
one which is shared between the Mobile Node and the Home Agent, one
between the Mobile Node and the Foreign Agent, and one between the
Foreign Agent and the Home Agent.
The keys destined for the Mobile Node are encrypted either using the
Mobile Node's secret or its public key [1]. The keys destined for the
Foreign Agent are encrypted either using the secret shared between
the AAAH and the AAAF, or using public key cryptography [1]. The keys
destined for the Home Agent can be either encrypted using the secret
it shares with the AAAH. The Session-Timeout AVP is included and
contains the number of seconds before the session keys expire. A
value of zero indicates that the session keys have no expiration.
Note that this extension requires a departure from the existing SPI
usage described in [4]. The AAAH generates SPI values for the
Mobility Agents as opposed to a receiver choosing its own SPI value.
The SPI values are used as Key Identifiers, meaning that each short-
lived session key has its own SPI value and since two nodes share a
session key they share an SPI as well.
Suppose a Mobile Node and a Foreign Agent share a key that was
created by the AAAH. The AAAH also generated a corresponding SPI
value of 37,496. All Mobile-Foreign Authentication extensions must be
computed by either entity using the shared session key would then
include the SPI value of 37,496.
The AAAH then sends a Home-Agent-MIP-Request (HAR) to the assigned or
requested Home Agent. The HAR contains the MIP-Registration-Request
as well as the keys and SPIs destined for the Home Agent (HA-to-MN-
Key, MN-HA-SPI, HA-to-FA-Key and FA-HA-SPI AVPs) and the Mobile Node
(MN-FA-SPI, MN-to-FA-Key, MN-HA-SPI and MN-to-HA-Key AVP). The
Mobile-Node-Address AVP contains an address if the Mobile Node
specified a home address or if the AAAH assigned an address, but no
address would be specified if the Home Agent were to assign one.
The Home Agent processes the DIAMETER Home-Agent-MIP-Request as well
as the embedded Mobile IP Registration Request. If both are
successfull, the Home Agent creates the Mobile IP Registration Reply,
and furthermore includes the keying material to be used by the Mobile
Node (MN-FA SPI, MN-to-FA-Key, MN-HA-SPI and MN-to-HA-Key) in the
MIP-Registration-Reply AVP. If no Mobile-Node-Address AVP was present
in the request the Home Agent must assign an address for the Mobile
Node. The Result-Code AVP is included and the Home-Agent-MIP-Answer
is sent to the AAAH.
The AAAH then issues a AA-Mobile-Node-Answer to the AAAF which
includes the MIP-Registration-Reply, Result-Code and the Mobile-
Node-Address AVP. The message also includes the keys and SPI AVPs
used by the Foreign Agent (MN-FA-SPI, FA-to-MN-Key, FA-HA-SPI and the
FA-to-HA-Key AVPs).
Upon receipt of the successful AA-Mobile-Node-Answer the AAAF
decrypts the FA-to-MN-Key and the FA-to-HA-Key AVPs. These keys are
then re-encrypted using the DIAMETER secret, unless IPSEC's ESP [x]
is used between the Foreign Agent and the AAAF. The message is
transmitted to the Foreign Agent.
The Foreign Agent, upon receipt of the AA-Mobile-Node-Answer,
decrypts the appropriate KEY AVPs, and processes the Mobile IP
Registration Reply which is then forwarded to the Mobile Node.
From this point on, all Registration Request and Replies need rely on
the DIAMETER proxy chain, the Foreign Agent can contact the Home
Agent directly using the keys which were previously distributed. This
can continue until the session keys expire, as indicated in the Key-
Lifetime AVP.
The following is an example of subsequent Mobile IP message exchange.
Mobile Node Foreign Agent Home Agent
----------- ------------- ----------
Reg-Req(MN-FA-Auth, MN-HA-Auth)-------->
Reg-Req(MN-HA-Auth, FA-HA-Auth)-------->
<--------Reg-Rep(MN-HA-Auth, FA-HA-Auth)
<--------Reg-Rep(MN-HA-Auth, MN-FA-Auth)
Note that subsequent registrations MUST use the MN-FA Authentication
extension[4].
4.2 Allocation of Home Agent in Foreign Network
When the AAAF receives the AMR message, it can add the Foreign-Home-
Agent-Available AVP to inform the AAAH that it is able and willing to
assign a Home Agent for the Mobile Node. The AAAH will only allow
this if the Home-Agent-Address in the AMR is set to zero (0). The
AAAH does this by sending the AMA message to the AAAF with the Home-
Agent-Address AVP set to zero (0). The AMA message still includes all
of the keying information that was previously discussed, except that
the keys for the Home Agent are encrypted using the security
association the AAAH shares with the AAAF.
ISP Home Network
+--------+ +--------+
| | AMR/A | |
| AAAF |<--------------->| AAAH |
| server | server-server | server |
+--------+ communication +--------+
/ /|\
HAR/A /AMR/A | client-server
/ | communication
|/_ \|/
+---------+ +---------+
| Home | | Foreign |
| Agent | | Agent |
+---------+ +---------+
/|\
| Mobile IP
|
\|/
+--------+
| Mobile |
| Node |
+--------+
Upon receipt of such a message, the AAAF issues the HAR message to
the Home Agent. Upon receipt of the response from the Home Agent the
AAAF issues the AMA message to the Foreign Agent in the same method
described earlier.
Mobile Node Foreign Agent AAAF Home Agent AAAH
----------- ------------- ------------- ---------- ----------
<-------Challenge
Reg-Req(Response)->
AMR------------->
AMR-------------------------->
<------------------------AMA
HAR------------->
<----------HAA
<------------AMA
<-------Reg-Reply
If the Mobile Node moves to another Foreign Network, which it detects
from the Router Advertisement message, it can either request to keep
the same Home Agent within the old foreign network, or it can request
that a new one be assigned. If the Home-Agent-Address AVP is set to a
value, it indicates that the same Home Agent should be used.
In this case the new AAAF would issue the AMR message towards the
Mobile Node's AAAH, which would create the keys as previously
defined. In this case all of the keys destined for the Home Agent
would be encrypted using the security association it shares with the
old Foreign Network's AAAF, while the keys for the Foreign Agent
would be encrypted using the security association shared with the new
Foreign Network's AAAF.
5.0 References
[1] Calhoun, Rubens, "DIAMETER", Internet-Draft,
draft-calhoun-diameter-07.txt, Work in Progress,
November 1998.
[2] Calhoun, Zorn, Pan, "DIAMETER Framework", Internet-
Draft, draft-calhoun-diameter-framework-01.txt,
Work in Progress, August 1998
[3] P. Calhoun, G. Montenegro, C. Perkins, "Tunnel Establishment
Protocol", draft-ietf-mobileip-calhoun-tep-01.txt,
Work in Progress, March 1998.
[4] C. Perkins, Editor. IP Mobility Support. RFC 2002, October
1996.
[5] P. Calhoun, C. Perkins, "Mobile IP Challenge/Response",
draft-ietf-mobileip-challenge-00.txt, Work in Progress,
November 1998.
[6] B. Aboba. "The Network Access Identifier." draft-ietf-roamops-
nai-11.txt, Work in Progress, July 1998.
[7] Aboba, Zorn, "Roaming Requirements", draft-ietf-roamops-
roamreq-09.txt, Work in Progress, April 1998.
[8] P. Calhoun, C. Perkins, "Mobile IP Dynamic Home Agent
Allocation", draft-ietf-mobileip-ha-alloc-00.txt,
Work in Progress, November 1998.
[9] P. Calhoun, W. Bulley, "DIAMETER Proxy Server Extensions",
draft-calhoun-diameter-proxy-00.txt, Work in Progress,
August 1998.
6.0 Authors' Addresses
Questions about this memo can be directed to:
Pat R. Calhoun
Technology Development
Sun Microsystems, Inc.
15 Network Circle
Menlo Park, California, 94025
USA
Phone: 1-650-786-7733
Fax: 1-650-786-6445
E-mail: pcalhoun@eng.sun.com
Charles E. Perkins
Technology Development
Sun Microsystems, Inc.
15 Network Circle
Menlo Park, California, 94025
USA
Phone: 1-650-786-6464
Fax: 1-650-786-6445
E-mail: charles.perkins@eng.sun.com
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