AAA WG Franck Le
INTERNET-DRAFT Basavaraj Patil
Date: November 2004 Charles E. Perkins
Expires: May 2005 Stefano Faccin
Nokia
Diameter Mobile IPv6 Application
<draft-le-aaa-diameter-mobileipv6-04.txt>
Status of This Memo
By submitting this Internet-Draft, I certify that any applicable
patent or other IPR claims of which I am aware have been disclosed,
and any of which I become aware will be disclosed, in accordance with
RFC 3668.
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Abstract
Mobile IPv6 capable mobile nodes can roam between networks that
belong to their home service provider as well as others. Roaming in
foreign networks is enabled as a result of the service level and
roaming agreements that exist between operators. One of the key
protocols that allows this kind of a roaming mechanism to be enabled
is Diameter. This Internet Draft specifies a new application to
Diameter that enables Mobile IPv6 roaming in networks other than its
home.
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Table of Contents
Status of This Memo . . . . . . . . . . . . . . . . . . . . . . . . i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. Advertising Application support . . . . . . . . . . . . . . . . . 2
3. The model and assumptions . . . . . . . . . . . . . . . . . . . . 2
3.1. The model . . . . . . . . . . . . . . . . . . . . . . . . . 2
3.2. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Basic features supported in this Internet Draft . . . . . . . . . 5
4.1. Authentication/authorization . . . . . . . . . . . . . . . . 5
4.2. Dynamic Home Agent assignment in Home domain . . . . . . . . 5
4.3. Key distribution . . . . . . . . . . . . . . . . . . . . . . 6
4.4. Optimization of Binding Updates . . . . . . . . . . . . . . 7
4.5. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5. Mobile IPv6 Application Diameter messages . . . . . . . . . . . . 7
5.1. Command Codes . . . . . . . . . . . . . . . . . . . . . . . 8
5.2. AVPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.2.1. MIP-Binding-Update AVP . . . . . . . . . . . . . . . . 8
5.2.2. MIP-Binding-acknowledgement AVP . . . . . . . . . . . . 8
5.2.3. MIPv6-Mobile-Node-Address AVP . . . . . . . . . . . . . 8
5.2.4. MIPv6-Home-Agent-Address AVP . . . . . . . . . . . . . 8
5.2.5. MIPv6-Feature-Vector AVP . . . . . . . . . . . . . . . 9
5.2.6. Security Key AVPs . . . . . . . . . . . . . . . . . . . 9
6. Information exchange between the mobile node and the AAA Client . 9
6.1. MIP Feature Data . . . . . . . . . . . . . . . . . . . . . . 9
6.2. EAP Data . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.3. Security Key Data . . . . . . . . . . . . . . . . . . . . . 10
6.4. Embedded Data . . . . . . . . . . . . . . . . . . . . . . . 10
7. Basic Protocol Overview . . . . . . . . . . . . . . . . . . . . . 10
7.1. Authentication . . . . . . . . . . . . . . . . . . . . . . . 11
7.2. Information flows . . . . . . . . . . . . . . . . . . . . . 11
7.3. MN Considerations . . . . . . . . . . . . . . . . . . . . . 12
7.3.1. Generation of information in MN . . . . . . . . . . . . 12
7.3.2. Replies to MN . . . . . . . . . . . . . . . . . . . . . 13
7.4. AAA Client Operation . . . . . . . . . . . . . . . . . . . . 13
7.5. AAAv Operation . . . . . . . . . . . . . . . . . . . . . . . 14
7.6. AAAh operations . . . . . . . . . . . . . . . . . . . . . . 15
7.7. Home Agent Behavior . . . . . . . . . . . . . . . . . . . . 16
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8. Enhanced features . . . . . . . . . . . . . . . . . . . . . . . . 17
8.1. Dynamic Home Agent/ Home Address assignment in Visited
domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.2. Dynamic Home address assignment in Home Domain . . . . . . . 18
8.3. Enhanced AVPs . . . . . . . . . . . . . . . . . . . . . . . 18
8.3.1. MIPv6-Feature-Vector AVP . . . . . . . . . . . . . . . 18
9. Enhanced Protocol Overview . . . . . . . . . . . . . . . . . . . 19
9.1. Information flow . . . . . . . . . . . . . . . . . . . . . . 19
9.2. MN Considerations . . . . . . . . . . . . . . . . . . . . . 20
9.2.1. Generation of information in MN . . . . . . . . . . . . 20
9.2.2. Replies to MN . . . . . . . . . . . . . . . . . . . . . 22
9.3. AAA Client Operation . . . . . . . . . . . . . . . . . . . . 22
9.4. AAAv Operation . . . . . . . . . . . . . . . . . . . . . . . 23
9.5. AAAh operations . . . . . . . . . . . . . . . . . . . . . . 24
9.5.1. Home Agent Assignement in Visited Network . . . . . . . 25
9.5.2. Home Agent Assignment in Home Network . . . . . . . . . 26
9.6. Home Agent Behavior . . . . . . . . . . . . . . . . . . . . 28
10. Key distribution . . . . . . . . . . . . . . . . . . . . . . . . 28
10.1. Key distribution based on Random numbers . . . . . . . . . 28
10.2. Key distribution based on Diffie Hellman . . . . . . . . . 29
11. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 30
12. Security Considerations . . . . . . . . . . . . . . . . . . . . 30
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
14. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32
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1. Introduction
Mobile IP defines a method that allows a Mobile Node to change its
point of attachment to the Internet with minimal service disruption.
Mobile IP in itself does not provide any specific support for
mobility across different administrative domains, which limits the
applicability of Mobile IP in a large scale commercial deployment.
AAA protocols such as Diameter precisely enable mobile users to roam
and obtain service in networks that may not necessarily be owned by
their home service provider. For Mobile IP to be deployed in
commercial networks, there therefore has to be AAA support for the
protocol.
Diameter extensions for Mobile IPv4 [1] have already been specified
allowing a MIPv4 node to receive services from service providers
(home and foreign) and allowing the Diameter servers to authenticate,
authorize and collect accounting information for those MIPv4 nodes.
Even though MIPv4 and MIPv6 are similar when observed at high level,
the two protocols are actually quite different when considering the
support for Inter Domain deployment. Mobile IPv6 e.g. does not have
the equivalent of a Foreign Agent as defined in Mobile IPv4, and as a
result does not define any mechanism by which the visited network can
authenticate and authorize access to the network and use of
resources. In addition, extending the Diameter Mobile IPv4
Application [1] to support Mobile IPv6 will reduce the flexibility
and result in some AAA capability exchange issues: it will be
difficult to differentiate which AAA nodes support only Mobile IPv4,
which ones support only Mobile IPv6 and which ones support both. This
document therefore provides a solution for Mobile IPv6 and AAA
interworking and e.g. defines the IPv6 specific solution to support
roaming of an IPv6 mobile node between different administrative
domains.
In order to give access to a mobile node to network resources, the
mobile node needs to be authenticated and authorized. Besides
supporting mobile node authentication and authorization, the AAA
infrastructure can also be used for distributing the security keys
needed to support the mobile node roaming. Optionally, the AAA
infrastructure can be used to support mobility procedures and to
optimize authentication, authorization and mobility in a common
procedure.
This internet draft defines the Diameter Mobile IPv6 application. It
identifies the information that needs to be exchanged between the MN
and the AAA Client but it does not specify any particular mechanism
to convey information between the mobile node and the AAA Client: the
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set of information identified in the following internet draft, can be
conveyed between the mobile node and the AAA client in a different
suitable manner outside the scope of this document (e.g. ICMP, the
protocol defined by the PANA WG, etc.). The extensions defined for
Diameter allow for any of these alternatives, thus enabling such
extensions to be deployed independently of the choice of the protocol
used between the MN and the AAA client in the visited or access
network.
The basic AAA model for inter domain roaming and the assumptions
behind the model are described first. The basic features supported by
the Diameter Mobile IPv6 application are described next, with the
definition of the Diameter messages and AVPs and with the behavior of
the various elements. Finally, enhanced features are described and
the AVPs and the behavior of the various elements is described.
2. Advertising Application support
Diameter nodes conforming to this specification MAY advertise support
by including the value of (TBD) in the Auth-Application-Id or the
Acct-Application-Id AVP of the Capabilities-Exchange-Request and
Capabilities-Exchange-Answer command [7].
3. The model and assumptions
3.1. The model
The following entities are involved in the model:
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Visited Domain Home Domain
+--------+ +--------+
|abc.com | (3) |xyz.com |
| AAAv |<------------------->| AAAH |
+->| server | server-server | server |
| +--------+ communication +--------+
| ^ ^
(2) | | (2) client-server | (4)
| | communication |
v v v
+---------+ +---------+ +---------+
| AAA | | AAA | | Home |
| Client | | Client | | Agent |
+---------+ +---------+ +---------+
^
| (1)
|
v
+--------+
| Mobile |
| Node | mn@xyz.com
+--------+
* The Mobile Node
* The AAA Client: it is the function that allows the MN to register
and be authenticated by the network service provider, by providing
identity and authentication information to the local network which
then uses a AAA infrastructure to validate the user, generate
accounting data for network usage and, authorize use of resources.
In addition to authorization and authentication, the MN may
provide the AAA Client with mobility management information (e.g.
embedded Binding Updates) to perform Mobile IP procedures. The AAA
Client can be an attendant, e.g. located in an Access Router, or
can be an AA Agent (Auth/Authorization agent) as the one
identified in UNAP.
* AAAv: is the AAA server in the visited network
* AAAh: is the AAA server in the home network of the MN
* HA: is a Home Agent
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3.2. Assumptions
1) Mobile nodes are identified by their Network Access Identifier
(NAI) in an unique manner:
RFC2794 specifies an identifier for mobile nodes, the MN-NAI. The MN-
NAI is used by the AAA infrastructure to authenticate mobile IPv4
nodes.
The Mobile IPv6 specification mandates the existence of a security
association between the MN and its Home Agent (HA). In certain
scenarios and future deployments a MN may not have any Home Agent or
a home address assigned to it. A MN may instead have a security
association with the home AAA network element and may use this to
obtain a home address, and an HA.
In this document it is assumed that an IPv6 mobile node SHOULD
identified by a MN-NAI in a unique manner, and that an IPv6 mobile
node SHOULD be able to use its NAI instead of its home address to get
authenticated/authorized by the AAA infrastructure when roaming to
foreign domains. In fact, in general the network needs to
authenticate the user that is roaming, not the specific device, and
in the future there may be cases where a specific user is accessing
the network through several devices, or several users are accessing
the network through the same device.
In general, anyway, it is better to allow identification of an IPv6
mobile node also through the use of its IPv6 home address: this
allows users that have not been provided with a NAI by their home
domain to get authenticated and authorized by the AAA infrastructure.
The assumption made in this document is that:
* When the identifier associated with a mobile is the MN-NAI, it
SHOULD use the MN_NAI to get authenticated/authorized by the AAA
infrastructure, independently of whether the MN has or not a home
address
* when the MN does not have a MN-NAI but only a home address, the MN
MAY use the IPv6 home address to get authenticated/authorized by
the AAA infrastructure
2) Mobile Node and AAAh share a long-term key:
This long-term key provides network authentication and user
authentication; it can also be used in order to derive session keys
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or local security associations as explained in the following
sections.
3) Communications between AAAv and AAAh are secure
This inter AAA security association allows the home and visited
domain to trust each other, and to exchange information in an
authenticated and protected manner.
4. Basic features supported in this Internet Draft
4.1. Authentication/authorization
Before giving access to the network, the visited network wants to
authenticate the user. The IPv6 mobile node may also want to
authenticate the network to prevent network impersonation such as
false BTS attacks.
The IPv6 mobile nodes SHOULD have the capability to use many
different authentication methods: The IPv6 mobile nodes could e.g.
use EAP at layer 3 for authentication: This document does not define
how the authentication information are exchanged between the Mobile
nodes and the network (it could be performed using the protocol
defined by the PANA WG, ICMPv6 messages) but the AAA infrastructure
allows that authentication and authorization; and the defined
Diameter messages support many round trips if the authentication
method adopted requires it.
4.2. Dynamic Home Agent assignment in Home domain
It is possible that when the mobile node needs to send a Binding
Update to its home agent to register its new primary care-of address,
the mobile node may not know the address of any router on its home
link that can serve as a home agent for it. For example, some nodes
on its home link may have been reconfigured while the mobile node has
been away from home, such that the router that was operating as the
mobile node's home agent has been replaced by a different router
serving this role.
The dynamic Home agent assignment feature also provides more
flexibility to the service provider: in general, a mobile node home
network may not assign statically a home agent to the mobile node to
maintain flexibility in the allocation of the home agent to achieve
better load sharing and fault tolerance.
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In this case, the mobile node MAY use the dynamic home agent address
discovery mechanism to find the address of a suitable home agent on
its home link.
The current Mobile IPv6 specification describes a dynamic Home Agent
discovery procedure; as an alternative, this document describes
another home agent assignment procedure relying on the present AAA
infrastructure.
Whereas the current dynamic home agent address discovery mechanism
requires many round trips between the mobile node and its home domain
thus resulting in additional signaling over the access link and
between the home and visited domains; and also adding more delay in
the procedure, the solution relying on the AAA infrastructure only
requires one round trip.
And instead of sending specific IP address to request for a Home
address/Home agent in the Home/Visited domain, the proposed solution
is based on flags: less data thus needs to be sent over the access
link, and the AAAh (AAAv) instead creates the binding update message
when assigning the home agent.
4.3. Key distribution
Many security associations need to be dynamically established such
as:
* the security association between the mobile node and the visited
network to protect data (e.g. confidentiality and integrity
protection) over the access link
* the security association between the mobile node and the home
agent, to authenticate the binding update/acknowledgement
messages. According to the current specifications, after the
dynamic home agent address discovery is performed, the mobile node
sends a Binding Update to the selected Home agent to create the to
create a forwarding entry in the route table for the home address
associated with the MN. This Binding Update MUST be authenticated,
therefore a key distribution, e.g. IKE, may need to be executed.
This requires many messages to be exchanged between the mobile
node and the Home Agent.
As an alternative, after the authentication and authorization steps,
the AAA servers can be involved and play a role in the key generation
and/or the key distribution.
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Diameter Mobile IPv4 Application defines one key distribution
mechanism; for Mobile IPv6, many different schemes could be applied
thus providing more flexibility and different properties as outlined
in the following sections.
4.4. Optimization of Binding Updates
As previously explained, in addition to authentication, authorization
and key distribution functionalities, the AAA servers can perform
mobility procedures such as dynamic home agent assignment. In case,
the IPv6 mobile node already has a pre-configured Home Agent, some
optimization can also be achieved by having the mobile node
encapsulating the binding update to its Home agent in the AAA request
message.
4.5. Summary
MN authentication is in general required to grant access to a MN to
the foreign domain. In fact, this may be needed in most of the cases
even if access to the foreign domain resources is free. Due to the
fact that the MN is away from its home network and hence considered
roaming the MN needs to perform also mobility procedures to obtain
reachability in the new location. Optionally, key distribution may be
need to take place. Using the AAA infrastructure to achieve these
functions can significantly reduce inter domain signaling and time
delay of the overall procedure performed by a MN to get access to the
foreign domain.
Currently the mobile node first gets authenticated using the AAA
infrastructure to obtain network access, then it may perform dynamic
home agent address discovery [4] and set up a security association
(using e.g. Internet Key Exchange [5]) with the selected Home agent
before sending a Binding Update. This will require many round trips
between the foreign domain and the home domain, whereas the use of
the AAA infrastructure provides a more efficient and quicker
alternative.
5. Mobile IPv6 Application Diameter messages
This memo introduces some new Command codes (AA-Registration-Request,
AA-Registration-Answer, Home-Agent-MIPv6-Request, Home-Agent-
MIPv6-Answer) and AVPs (MIP-Binding-Update AVP, MIP-Binding-
acknowledgement AVP, MIPv6-Mobile-Node-Address AVP, MIPv6-Home-Agent-
Address AVP, MIPv6-Feature-Vector AVP, Key-Request AVP, MN-Key-
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Distribution AVP, Key-Distribution AVP) to achieve all the previously
identified functionalities.
5.1. Command Codes
This document introduces four new Command Codes:
* AA-Registration-Request Command (ARR) (Code TBD)
* AA-Registration-Answer Command(ARA) (Code TBD)
* Home-Agent-MIPv6-Request Command (HOR) (Code TBD)
* Home-Agent-MIPv6-Answer Command (HOA) (Code TBD)
5.2. AVPs
5.2.1. MIP-Binding-Update AVP
The MIP-Binding-Update AVP (AVP Code TBD) is of type OctetString and
contains the Mobile IP Binding Update message.
5.2.2. MIP-Binding-acknowledgement AVP
The MIP-Binding-acknowledgement AVP (AVP Code TBD) is of type
OctetString and contains the Mobile IP Binding Acknowledgement
message sent by the Home Agent to the MN.
5.2.3. MIPv6-Mobile-Node-Address AVP
The Mobile-Node-Address AVP (AVP Code TBD) is of type IPAddress and
contains the Mobile Node's Home Address.
5.2.4. MIPv6-Home-Agent-Address AVP
The Home-Agent-Address AVP (AVP Code TBD) is of type IPAddress and
contains the Mobile Node's Home Agent Address.
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5.2.5. MIPv6-Feature-Vector AVP
The MIPv6-Feature-Vector AVP (AVP Code TBD) is of type Unsigned32 and
allows for dynamic Home Agent assignment in Home Domain. In the basic
proposal, only one flag is defined; the other ones are reserved for
the enhanced version and for future utilization.
Flag values currently defined include:
1 Home-Agent-Requested: This flag is set to 1 when the
mobile node requests for a dynamic home agent
assignment. When this flag is set to 1, a dynamic
session key to be shared between the MN and the HA is
also required in order to authenticate BUs from the MN
to the HA: the MN may indicate through some Security Key
Request the methods it supports to compute it; or a
default method known to the MN and the AAAh should
exist(e.g. pre-set by the home domain and communicated
to the MN at subscription time).
5.2.6. Security Key AVPs
The AAA servers can play a role in key distribution and many methods
can be used with their own properties and characteristics. The
security keys AVPs format and utilization will be described in more
details in the next versions as well as the AAA servers' behaviors.
6. Information exchange between the mobile node and the AAA Client
Although this document is not intended to specify any particular
mechanism to convey information between the mobile node and the AAA
Client, the information that needs to be exchanged is described. The
set of information identified in the follow can actually be conveyed
between the mobile node and the network in a different suitable
manner outside the scope of this document (e.g. ICMP, the protocol
defined by the PANA WG, etc.). The extensions defined for Diameter
allow for any of these alternatives, thus enabling such extensions to
be deployed independently of the choice of the protocol used between
the MN and the network.
6.1. MIP Feature Data
Contrary to Mobile IPv4 where the Mobile nodes send a Registration
Request with specific IP addresses values to request for dynamic home
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agent assignment in home/visited networks; the IPv6 mobiles nodes
SHOULD use some MIP Feature data whose content includes the
information required in the previously defined MIPv6 Feature Vector
AVP: The IPv6 mobile nodes will not use specific IPv6 addresses
values but use flags and this will significantly reduces the amount
of data to be sent over the access link. In addition, the attendant
will only need to encapsulate that data in the corresponding
MIPv6-Feature-Vector AVP.
The MIP Feature data could be sent as an extension to ICMPv6
messages, a new Destination Option or carried in any other way.
6.2. EAP Data
The IPv6 Mobile Node should be able to use different authentication
methods such as the different EAP types.
The EAP Data could be sent as an extension to ICMPv6 messages,
carried using the protocol defined by the PANA WG or any other
protocol.
6.3. Security Key Data
This document does not defines the protocol between the mobile nodes
and the network but the mobile node SHOULD use some key request to
indicate the keys it needs, but also the methods it supports to
generate them.
Those Security Key data SHOULD contain the relevant information so
the AAA client can create the corresponding Security Keys AVPs.
6.4. Embedded Data
The embedded data enables the mobile node to send a binding update at
the same time the mobile node gets authorized/authenticated by the
network (e.g. by mechanism that the protocol defined by the PANA WG
will provide) thus saving round trips between the home and the
visited domains.
7. Basic Protocol Overview
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7.1. Authentication
Authentication is required before providing network access to the
user.
Different authentication should be supported to allow more
flexibility; but as demonstrated in [6], both network and user
authentication should be supported.
And current authentication mechanisms, even those recently specified
in different standardization fora (e.g. CAVE based security functions
in IS41 Systems) have security flaws.
For these reasons, even as previously mentioned any existing
authentication could be used, in the following illustrations and
procedures, a mutual challenge response based authentication method
will be suggested and used as default.
The authentication mechanism assumed here assumes that a Local
Challenge is broadcast over the access link e.g. in Router
Advertisement messages.
7.2. Information flows
Basic Procedure with dynamic Home Agent assignment in the Home
network or pre-configured Home Agent
Mobile Node AAA Client AAAv AAAh Home Agent
----------- ----------- ------------ ---------- ----------
Advertisement &
<---1.1 - Challenge
-1.2 -------->
1.3 ARR------------->
1.4 ARR------------>
1.5 HOR------->
<------1.6 HOA
<---------1.7 ARA
<------------1.8 ARA
<-------1.9
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7.3. MN Considerations
7.3.1. Generation of information in MN
1) When entering a new network or at power up, the MN listens to the
router advertisements and retrieves:
The Local Challenge
The visited network identifier
The information to derive the CoA
2) It computes the CoA, and based on the following information,
* The NAI
* The long-term security key shared with its AAAh
* The Home Address: in the basic mode, the mobile node is
assumed to have a pre-configured Home IP address
* The Home Agent (if any), otherwise MN can request to have one
assigned
creates a message with the CoA as the Source IP address and the AAA
Client address as the Destination IP address. (The MN can learn the
IP address of the AAA Client through router advertisements or others
mechanisms outside the scope of this document.) As previously
explained, the mobile node also sends its NAI.
3) The MN optionally generates a Host Challenge that it will send to
the network for both network authentication and anti replay attacks.
Then the MN computes the MN authentication data using the long-term
key, the host challenge, the visited network identifier, the local
challenge, and an authentication algorithm it shares with its home
network. The MN authentication data is then sent to the AAA Client,
4) If the MN does not have a Home Agent and requests one, the MN
includes some MIP Feature data with the Home-Agent-Requested flag set
to 1. The home agent will then be assigned by the home AAA server,
and the binding update will be sent by the AAA server to the Home
Agent on behalf of the mobile node that, in turn, does not need to
send any.
If the MN have a pre configured Home Agent, it may creates the
binding update message and sends it encapsulated to the AAA client.
The Binding Update message will be forwarded to the designated home
agent via the AAA infrastructure. This binding update message has
the MN IP CoA as the source IP address, the pre-configured HA as the
destination IP address and the BU option with the pre-configured Home
IP address in the Home address option.
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5) The MN may also requests for some security keys thanks to the
Security Key Request.
The MN SHOULD perform authentication in the following cases:
* When changing visited domain: MN can know that by
listening the router advertisements
* When requesting session keys
* When requesting a Home Agent assignment
7.3.2. Replies to MN
When receiving the reply from the AAA Client, the MN:
* Authenticates the network thanks to the network authentication
data sent by the AAA Client
* If the MN requested a Home agent, it will learn and store the Home
Agent address from the source IP address of the Home Binding
Acknowledgement.
The MN creates the security associations from the keying material
received.
7.4. AAA Client Operation
As indicated above, the mobile node may interact with the AAA Client
to perform authentication/authorization and optionally Mobile IP
procedures. Thus, the AAA client may perform authentication functions
and optionally Mobile IP functions
When the AAA Client receives an authentication request message from a
IPv6 Mobile node:
The AAA Client first verifies the freshness of the request thanks to
the Local Challenge contained in it (i.e. the MN may use an older
Local Challenge) and if successful, performs Duplicate Address
Detection and creates a Diameter ARR (AA-Registration-Request) [7]
message carrying the following information to the AAAh:
* User Name AVP [7] carrying the user's NAI
* EAP AVP to carry the authentication data for mutual authentication
derived from the content of the received authentication data
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* if some MIP feature data were received from the MN, a
MIPv6-Feature-Vector AVP whose content is derived from the MIP
feature data, sent within the ARR message it sends to the AAAv
* MIP-Binding Update AVP if the MN sent a Home Binding Update as
Embedded data
* MIPv6-Home-Agent-Address AVP if the MN sent a binding update
message: the Home agent address value is extracted from the
Destination IP address field of the embedded home binding update.
This AVP enables the AAAh to know where to send the MIP-Home-
binding-Update AVP if one was present.
* if the MN provides some Key Request data, some Security Key AVPs
whose content is derived from the Key Request data.
When receiving an ARA [7] (AA-Registration-Answer) message from AAAv,
the AAA Client converts the message to the appropriate protocol to
the MN; this message carries:
* the authentication data
* Binding Acknowledgement as Embedded Data if MN sent a home Binding
Update or requested for a dynamic home agent assignement.
The message may also include:
* Keying material to set up the different session keys, converted
and conveyed in the appropriate protocol by the AAA Client from
the Security Key AVPs. When the MN asks for a dynamic Home Agent,
AAAh SHOULD compute the security key to be shared between MN and
the HA for authenticating subsequent Binding Updates, and sends
the corresponding keying material to the MN.
7.5. AAAv Operation
When AAAv receives an ARR message [7]:
First the AAAv verifies the message is coming from a valid AAA Client
and then, checks the MIPv6 Feature Vector AVP, and then sends it to
the MN's home AAA server.
When receiving a ARA message from the AAAh, the AAAv MAY optionally,
according to the behaviour specific for speficic EAPs or other
mechanisms defined elsewhere, store locally information contained in
the AVPs of the message received from the AAAh (e.g. session keys,
etc.) and then forwards the message to the AAA Client.
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7.6. AAAh operations
* When receiving an ARR message from an AAAv, the AAAh first
verifies the message is coming from a valid AAAv. Security
associations between AAA server are outside the scope of the
present document.
The AAAh then authenticates the user using the NAI provided by the MN
as MN identity. If the mobile Node is successfully authenticated:
* AAAh also computes some network authentication data based on the
Host Challenge and eventually other information depending on the
authentication algorithm adopted.
Depending on the authentication method requirements, the AAAh may
exchange many messages with the MN via the AAAv (e.g. for a user
authentication mechanism that requires more than one round-trip):
AAAh may send a ARA Command with the appropriate authentication
information and indication, which will be converted to EAP data by
the AAA Client to the MN and conveyed to the MN in a suitable manner
(outside the scope of this document). The number of round trips
varies depending on the authentication mechanism used.
* If the MN asks for some security keys, the AAAh performs the
appropriate steps and eventually sends the corresponding messages
to achieve the key distribution: many mechanisms exist and some of
them will be described later on. Such steps may require the AAAh
to distribute keys and keying material to the MN, to other AAA
servers or other nodes.
* If a MIPv6-Home-Agent-Address AVP is present: the AAAh checks that
the address is that of a known and valid Home Agent, and one that
the Mobile Node is allowed to request. AAAh then forwards the MIP-
Home-Binding-Update AVP to the Home Agent in a HOR (Home-Agent-
MIP-Request) message.
* If no MIPv6-Home-Agent-Address AVP is present, AAAh looks at the
MIPv6-Feature-Vector AVP if any. If present, AAAh performs the
dynamic home agent assignment in the Home network:
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Mobile Node AAA Client AAAv AAAh Home Agent
----------- ----------- ------------ ---------- ----------
Advertisement &
<---1.1 -- Challenge
-1.2 -------->
1.3 ARR------------->
1.4 ARR---------->
1.5 HOR------->
<--------1.6 HOA
<-------1.7 ARA
<------------1.8 ARA
<-------1.9
(1.5) AAAh allocates a Home agent on behalf of the MN: this can be
done in a variety of ways, including using a load balancing
algorithm in order to keep the load on all HAs equal.
* AAAh sends a HOR message to the HA including a newly created
binding update.
* AAAh sends some security keying material to allow the Home
Agent to comupte the key(s) for the security association
between the MN and the Home Agent to authenticate future
Binding Updates.
(1.6) the Home Agent creates the Binding Cache and computes the
key(s) for the security association with the MN from the data
received. It also generates a Binding Acknowledgement message to
be sent encapsulated to the MN.
* The HA sends a HOA message to the AAAh including the Binding
Ack.
(1.7) AAAh may also compute other keying material according to the
keys requested by the MN and send it to the MN passing through the
AAAv.
* AAAh then send an ARA message to the AAAv including the MIP-
Binding-acknowledgement AVP if the MN sent an embedded BU or
request for a HA.
7.7. Home Agent Behavior
Upon receipt of the HOR, the Home Agent first processes the DIAMETER
message: if the HOR is invalid, a HOA is returned with the Result-
Code AVP set to DIAMETER_ERROR_BAD_HOR. Otherwise, the Home Agent
processes the MIP-Binding-update AVP and creates the Binding
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Acknowledgement, encapsulating it within the MIP-binding-
acknowledgement AVP.
HA also creates the Binding Cache and computes the key(s) for the
security association with the MN from the data received.
8. Enhanced features
In addition to the previously described features, additional features
can be supported by the AAA infrastructure for the inter-domain
roaming of an IPv6 mobile node, thus providing more flexibility and
allowing new options to the services providers to develop business
models.
A IPv6 mobile node can have a pre-configured home address, may have a
pre-configured home agent or request for one and, as explained in the
previous section, the basic features of the Mobile IPv6 Diameter
Application allow an optimization of the authentication, the binding
update, the optional home agent assignment in the home domain and the
key distribution procedures.
Optionally, two enhanced features are suggested:
* The dynamic Home agent assignment in the Visited Domain
* The dynamic Home address assignment
8.1. Dynamic Home Agent/ Home Address assignment in Visited domain
The Dynamic Home Agent assignment in visited networks allows more
flexibility and allows new business scenarios. As an example, service
providers may just own a AAA server for accounting purposes and,
thanks to roaming agreements, they may offer Mobile IP services to
its subscribers. Another scenario where this can be applied is when
IPv6 mobile nodes need to obtain reachability from other CN only at
the application level, i.e. through a SIP infrastructure. This may be
the case of a basic IPv6 MN supporting only voice services through
SIP. In such cases, when a CN needs to reach the MN an identifier at
the application level (e.g. MN SIP URL) is used, and the CN does not
need to know the home address of the MN. Somebody may argue that
Mobile IP is not needed at all in such cases, but it may instead be
used to support mobility between the initial point of attachment
(i.e. when the MN powered up in the foreign domain) and following
points of attachment in the foreign domain.
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8.2. Dynamic Home address assignment in Home Domain
The mobile node may not always have a pre-configured IPv6 address and
may need to have one dynamically assigned. In addition since the Home
Agent and the mobile node home address need to be on the same link,
to support dynamic home agent assignment in visited networks, dynamic
home address assignment in visited networks is supported.
Finally, this dynamic Home address feature provides more flexibility
to the service provider even when the Home agent is to be assigned in
the Home network since the Home agent and the home address should be
on the same subnet. Additionally, the scenario described in section
7.2 of a MN node needing reachability only at the application layer
applies to this case too.
8.3. Enhanced AVPs
In addition to the Command Codes and AVPs described in section 4,
some new AVP need to be defined to support the enhanced features.
8.3.1. MIPv6-Feature-Vector AVP
In the extended mode, dynamic home agent assignment in the visited
network is feasible.Additional flags of the MIPv6-Feature-Vector AVP
are therefore defined.
The following flags allow the Visited AAA server, AAAv, to inform of
its capabilities and if the Home agent is assigned in the visited
network, the Home address must also be assigned in the visited
network.
The AAA Client includes a MIPv6-Feature-Vector AVP within the ARR
message it sends to the AAAv if the MN sent some MIP Feature data.
Flag values currently defined include:
1 Home-Agent-Requested: This flag is set to 1 when the
mobile node requests for a dynamic home agent
assignment. When this flag is set to 1, a dynamic
session key to be shared between the MN and the HA is
also required in order to authenticate BUs from the MN
to the HA: the MN may indicate through some Security Key
Request the methods it supports to compute it; or a
default method known to the MN and the AAAh should
exist(e.g. pre-set by the home domain and communicated
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to the MN at subscription time).
2 Mobile-Node-Home-Address-Requested flag: This flag is
set to 1 if the mobile node does not have any Home
address and requires one. Default value is 0.
4 Home-Address-Allocatable-Only-in-Home-Domain flag: This
flags is set to 1 if the mobile node requests for one
Home address and wants it to be assigned by its home
network. Default value is 0 and means that the MN does
not have any preference on whether the Home Address
shall be allocated in the home domain and visited
domain.
8 Home-Agent-in-Visited-Domain flag: The mobile node
indicates its preference to have its Home Agent
allocated in the visited domain by having this flag set
to 1
16 Visited-Home-Agent-Available flag: The Visited Domain
sets this flag to 1 if the MN asks a dynamic Home Agent
assignment in the Visited Domain and the Visited Domain
agrees to allocate one to the MN.
9. Enhanced Protocol Overview
The enhanced mode allows dynamic home agent assignment in the visited
network and dynamic home address assignment. The mobile node may not
have any preconfigured home address nor any home agent. The following
text describes the different entities' behaviors in the Enhanced
mode.
The authentication procedure is the same than the one described
above.
All the functionalities (key distribution, optimization of Binding
Upate, dynamic Home Agent assignment in Home network) of the basic
mode are present but in addition the Home agent can be assigned in
the visited network and the home address can be dynamically assigned
either in the home or visited domain: the entities behaviours and the
way the corresponding AVPs are processed, are explained
9.1. Information flow
Enhanced Procedure with dynamic Home agent assignment in the visited
network and dynamic home address assignment in home or visited domain
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Mobile Node AAA Client Home Agent AAAv AAAh
----------- ----------- ------------- ---------- ----------
<---2.1 Challenge---
-2.2 ----->
----------2.3 ARR------------->
---2.4 ARR---->
<--2.5 HOR-----
<---2.6 HOR---
----2.7 HOA--->
---2.8 HOA---->
<--2.9 ARA-----
<-----------2.10 ARA------------
<-2.11--
9.2. MN Considerations
9.2.1. Generation of information in MN
The mobile node performs the same steps as in the basic mode (steps
(1), (2), (3) section 6.3.1) and then
4) If the MN does not have a Home Address and requests one, the MN
also includes some MIP Feature data with the Mobile-Node-Home-
Address-Requested flag set to 1:
* If MN wants its Home address to be allocated by its home network,
it also sets the value of Home-Address-Allocatable-Only-in-Home-
Domain flag to 1.
If the MN does not have a Home Agent and requests one, the MN also
includes some MIP Feature data with the Home-Agent-Requested flag set
to 1. The home agent will then be assigned by the AAA server, and the
binding update will be sent by the AAA server to the Home Agent on
behalf of the mobile node that, in turn, does not need to send any.
* If MN wants its Home agent to be allocated by the visited network,
it also sets the Home-Agent-in-Visited-Network flag to 1.
The following table describes the different supported cases and the
flags that need to be set according to the needs:
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INTERNET-DRAFT Diameter Mobile IPv6 Application November 2004
HD means Home Domain
VD means Visited Domain
NP means MN has No Preference
X means not supported
P: Mobile-Node-Home-Address-Requested flag
H: Home-Address-Allocatable-Only-in-Home-Domain
A: Home-Agent-Requested
V: Home-Agent-In-Visited-Network
+---------+------------------------------------------------+
| | Home agent Requested |
+---------+---+--------------------+-----------------------+
| | | YES | NO |
| +---+--+-----+-----+-----+-----------------------+
| | | | HD | VD | NP | |
|Home addr| +--+-----+-----+-----+-----------------------+
|Requested| |HD| PAH | x | x | PH |
| | +--+-----+-----+-----+-----------------------+
| |YES|VD| x |PAV | x | x |
| | +--+-----+-----+-----+-----------------------+
| | |NP| x | x |PA | P |
| +---+--+-----+-----+-----+-----------------------+
| | | | | | | |
| | NO| | A* | x | x | no MIP Feature data |
| | | | | | | |
+---------+---+--+-----+-----+-----+-----------------------+
A*: MN already has a home address in its Home network and may request
for a Home Agent. The HA can thus only be assigned in the Home
Network.
While the MN gets authenticated and authorized, if the MN already has
a home address and a home agent, it can send a Home Binding Update
together with the request to be authorized and authenticated to save
one round trip over the access link and between the visited and home
networks. This binding update is in this case sent as Embedded Data:
The Home Binding Update has:
* The H flag set to 1.
* The source IP address equals to the CoA
* The destination IP address set to the Home agent address
* The Home Address option set to the MN Home address
5) The MN may also requests for some security keys thanks to the
Security Key Request.
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The MN SHOULD perform authentication in the following cases:
* When changing visited domain: MN can know that by
listening the router advertisements
* When requesting session keys
* When requesting a Home Agent assignment
* When requesting a home address assignment
9.2.2. Replies to MN
When receiving the reply from the AAA Client, the MN:
* Authenticates the network thanks to the network authentication
data sent by the AAA Client
* If the MN requested a Home agent, it will learn and store the Home
Agent address from the source IP address of the Home Binding
Acknowledgement.
* If the MN did not have a Home IP address and requested for one,
the MN will learn and store the assigned home address from the
home address option of the Home Binding Acknowledgement (embedded
data).
The MN creates the security associations from the keying material
received.
9.3. AAA Client Operation
As indicated above, the mobile node may interact with the AAA Client
to perform authentication/authorization and optionally Mobile IP
procedures. Thus, the AAA client may perform authentication functions
and optionally Mobile IP functions
When the AAA Client receives an authentication request message from a
IPv6 Mobile node:
The AAA Client first verifies the freshness of the request thanks to
the Local Challenge contained in it (i.e. the MN may use an older
Local Challenge) and if successful, performs Duplicate Address
Detection and creates a Diameter ARR (AA-Registration-Request) [7]
message carrying the following information to the AAAh:
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* User Name AVP [7] carrying the user's NAI
* EAP AVP to carry the authentication data for mutual authentication
derived from the content of the received authentication data
* if some MIP feature data were received from the MN, a
MIPv6-Feature-Vector AVP whose content is derived from the MIP
feature data, sent within the ARR message it sends to the AAAv
* MIP-Binding Update AVP if the MN sent a Home Binding Update as
Embedded data
* MIPv6-Home-Agent-Address AVP if the MN sent a Home binding update:
the Home agent address value is extracted from the Destination IP
address field of the embedded home binding update. This AVP
enables the AAAh to know where to send the MIP-Home-binding-Update
AVP if one was present.
* if the MN provides a Key Request, some Security Key AVPs whose
content is derived from the Key Request.
When receiving an ARA [7] (AA-Registration-Answer) message from AAAv,
the AAA Client converts the message to appropriate protocol to the
MN; this message carries:
* the authentication data
* Binding Acknowledgement as Embedded Data if MN sent a home Binding
Update or requested for a dynamic home agent assignment.
The message may also include:
* Keying material to set up the different session keys, in different
Security Key Data created by the AAA Client from the Security Key
AVPs. When the MN asks for a dynamic Home Agent, AAAh must compute
the security key to be shared between MN and the HA for
authenticating subsequent Binding Updates, and sends the
corresponding keying material to the MN.
9.4. AAAv Operation
When AAAv receives an ARR message [7]:
First the AAAv verifies the message is coming from a valid AAA Client
and then, checks the MIPv6 Feature Vector AVP:
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* If the MN requested a Home Agent by setting the Home-Agent-
Requested flag to 1, and does not specify that this one should be
assigned only in its Home domain by setting the Home-Address-
Allocatable-Only-in-Home-Domain flag to 1, the AAAv checks if it
can allocate a Home Agent for the mobile node in the visited
domain. If AAAv can allocate a Home Agent in the visited domain,
it indicates this to the AAAh by setting the Visited-Home-Agent-
Available flag to 1 of the MIPv6 Feature Vector AVP forwarded to
the AAAh.
When receiving a HOR message from the AAAh for a dynamic Home Agent
assignment in the visited network, the AAAv performs the dynamic Home
agent assignment and MAY perform some key distribution depending on
the mechanisms.
When receiving a ARA message from the AAAh, the AAAv MAY optionally,
according to the behavior specific for speficic EAPs or other
mechanisms defined elsewhere, store locally information contained in
the AVPs of the message received from the AAAh (e.g. session keys,
etc.) and then forwards the message to the AAA Client.
9.5. AAAh operations
* When receiving an ARR message from an AAAv, the AAAh first
verifies the message is coming from a valid AAAv. Security
associations between AAA server are outside the scope of the
present document.
The AAAh then authenticates the user using the NAI provided by the MN
as MN identity. If the mobile Node is successfully authenticated:
* AAAh also computes some network authentication data based on the
Host Challenge and eventually other information depending on the
authentication algorithm adopted.
Depending on the authentication method requirements, the AAAh may
exchange many messages with the MN via the AAAv (e.g. for a user
authentication mechanism that requires more than one round-trip):
AAAh may send a ARA Command with the appropriate authentication
information and indication, which will be converted to EAP data by
the AAA Client to the MN or conveyed to the MN in other suitable
manner (outside the scope of this document). The number of round
trips varies depending on the authentication mechanism used.
* If the MN asks for some security keys, the AAAh performs the
appropriate steps and eventually sends the corresponding messages
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to achieve the key distribution: many mechanisms exist and will be
described later on. Such steps may require the AAAh to distribute
keys and keying material to the MN, to other AAA servers or other
nodes.
* If a MIPv6-Home-Agent-Address AVP is present: the AAAh checks that
the address is that of a known and valid Home Agent, and one that
the Mobile Node is allowed to request. AAAh then forwards the MIP-
Home-Binding-Update AVP to the Home Agent in a HOR (Home-Agent-
MIP-Request) message including the appropriate key material to set
up the security association between the MN and the Home Agent.
* If no MIPv6-Home-Agent-Address AVP is present, AAAh looks at the
MIPv6-Feature-Vector AVP if any. Depending on the mobile node
request (Home-Agent-in-Visited-Network flag, Home-Address-
Allocatable-Only-in-Home-Domain), the visited network capabilities
(Visited-Agent-Available AVP) and the local policy, the AAAh
decides whether to assign the HA in the home or visited network:
9.5.1. Home Agent Assignement in Visited Network
If the AAAh accepts the HA to be assigned in the visited domain, the
following exchange of messages takes place:
Mobile Node AAA Client Home Agent AAAv AAAh
----------- ----------- ------------- ---------- ----------
<---2.1 Challenge-
-2.2 ---->
----------2.3 ARR------------->
---2.4 ARR---->
<--2.5 HOR-----
<---2.6 HOR-----
----2.7 HOA----->
---2.8 HOA---->
<--2.9 ARA-----
<-----------2.10 ARA------------
<-2.11 ---
(2.5): AAAh sends a HOR message to the AAAv with neither any
MIPv6-Mobile-Node-Address AVP nor any MIPv6-Home-Agent-Address
AVP.
* AAAh may send some keying material for HA to derive the key(s)
for the security association between the MN and the Home Agent
to authenticate future Binding Updates depending on the key
distribution mechanism chosen
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* AAAh may also send other keying material according to the keys
requested by the MN
(2.6): AAAv assigns a Home agent and then creates and sends it a
newly created Binding Update encapsulated in the HOR message.
* AAAv may assign Home IP address for the MN and informs the Home
Agent by adding a MIPv6-Mobile-Node-Address AVP in the HOR
message; or let the Home Agent assigns the Home address by not
providing a MIPv6-Mobile-Node-Address AVP in the HOR message.
* AAAv may forward to the Home Agent some keying material
depending on the key distribution mechanism adopted to set up
the security association between the MN and the Home Agent
(2.7): The Home agent assigns a Home IP address if requested and
creates a Binding Cache for the MN.
* The Home agent creates the Security Association according to
the mechanism adopted
* The Home Agent creates the Binding Acknowledgement to be sent
encapsulated to the MN.
* The Home Agent sends back a HOA to the AAAv to inform it of the
status: it includes the assigned Mobile Node Home Address if
the Home Agent assigned one; it also includes the Binding ack
created by the Home Agent to be sent encapsulated to the MN.
(2.8) The AAAh is informed of the assigned Home IP address
(contained in the MIPv6-Mobile-Node-Address AVP) and the Home
Agent address (contained in the MIPv6-Home-Agent-Address AVP) by
the HOA message sent from the AAAv.
(2.9) The AAAh sends the AAAv an ARA carrying the Home IP address,
the Home Agent IP address, the keying material with the previous
information.
9.5.2. Home Agent Assignment in Home Network
If the AAAh decides to assign the HA in the Home network, the
following exchange of messages takes place:
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Mobile Node AAA Client AAAv AAAh Home Agent
----------- ----------- ------------ ---------- ----------
Advertisement &
<---3.1 -- Challenge
-3.2 ----->
3.3 ARR------------->
3.4 ARR-------->
3.5 HOR------>
<----3.6 HOA
<------3.7 ARA
<------------3.8 ARA
<-------3.9
(3.5) AAAh allocates a Home agent on behalf of the MN: this can be
done in a variety of ways, including using a load balancing algorithm
in order to keep the load on all HAs equal.
* AAAh sends a HOR message to the HA including a newly created
binding update and:
* The AAAh may allocate a home address for the mobile node and
include it in a MIPv6-Mobile-Node-Address AVP within the HOR or
else leave this allocation responsibility for the HA by leaving
the Home address option of the binding update to zero and not
sending any MIPv6-Mobile-Node-Address AVP.
* AAAh sends some security keying material to allow the Home Agent
to compute the key(s) for the security association between the MN
and the Home Agent to authenticate future Binding Updates.
(3.6) If the Home Agent does not receive any MIP-Mobile-node-address,
and receives a BU with a Home address equals to 0, it assigns a Home
IP address for that user; then creates the Binding Cache and computes
the key(s) for the security association with the MN from the data
received. It also generates a Binding Acknowledgement message to be
sent encapsulated to the MN.
* The HA sends a HOA message to the AAAh including the Binding Ack
and eventually the assigned Home IP address if one was requested.
(3.7) AAAh may also compute other keying material according to the
keys requested by the MN and send it to the MN passing through the
AAAv.
* AAAh then send an ARA message to the AAAv including the
MIPv6-Mobile-Node-Address and MIPv6-Home-Agent-Address AVPs if the
MN did not have any Home address or Home agent.
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9.6. Home Agent Behavior
Upon receipt of the HOR, the Home Agent first processes the DIAMETER
message: if the HOR is invalid, a HOA is returned with the Result-
Code AVP set to DIAMETER_ERROR_BAD_HOR. Otherwise, the Home Agent
processes the MIP-Binding-update AVP and creates the Binding
Acknowledgement, encapsulating it within the MIP-binding-
acknowledgement AVP.
If a home address is needed, the Home Agent assigns one and includes
the address in both the Binding acknowledgement message (Home address
option) and in the MIPv6-Mobile-Node-Address AVP.
HA then creates the Binding Cache and computes the key(s) for the
security association with the MN from the data received.
10. Key distribution
As identified in the previous sections, many security keys need to be
set up and shared between the IPv6 mobile nodes and other network
entities, such as:
* the key between the mobile node and its Home Agent to authenticate
the binding Update and Binding acknowledgement messages
* the key between the mobile node and the access router to protect
(e.g. for confidentiality and integrity protection) the data over
the access link.
The AAA entities can play a major role in the computation and
distribution of these security keys. Two key distribution methods,
relying on this AAA infrastructure and allowing authenticated key
distribution, are proposed.
10.1. Key distribution based on Random numbers
The home AAA server generates one random number for each required
security key. Then taking as inputs, to a key derivation algorithm
shared with the mobile node, this random number, the long term key
shared with the mobile node and optionally other data, the home AAA
server derives the desired security key.
This one is securely transmitted to the network entity, the mobile
node wants to share the key with.
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And the random number is sent to the Mobile node which can derive the
security session key thanks to the knowledge of the long term key and
the key derivation algorithm shared with its home network.
This key distribution based on Random numbers is currently used in
cellular networks and in the Diameter Mobile IPv4 Application [1]
10.2. Key distribution based on Diffie Hellman
As another possibility, the key distribution can be based on the
Diffie Hellman mechanism.
Diffie Hellman allows two nodes to establish a shared secret key in a
secure fashion. It, although, has a major vulnerability since it does
not allow a node to figure out with whom it is establishing that
secret key. To defeat this vulnerability, the two nodes public values
must be authenticated.
The AAA infrastructure, and more particularly the security
association between the Mobile node and its home network (AAAh) and
the security association between the AAAv and AAAh, can provide that
authentication.
If the mobile node wants to set up a securiy association with an
entity in the visited domain (e.g. home agent assigned in the visited
domain), the mobile node first sends its public Diffie Hellman value
DH_MN authenticated with the long term security association shared
with its AAAh. If the entity with whom the MN wants to set up a
security association is in the visited domain, AAAv retrieves the
entity's Diffie Hellman public value using intra domain security and
sends this value, authenticated with the security association it
shares with the AAAh, to the home network of the MN together with the
message from the MN.
AAAh authenticates the Diffie Hellman Public values of the entity and
the MN. It then sends the MN's Diffie Hellman Public Value to the
AAAv using the security association it shares with AAAv, and sends
the entity's Diffie Hellman Public Value to the MN, authenticated
with the security association shared with the MN.
In this way, AAAh is used to authenticate the Diffie Hellman public
values but as a difference with the previous method, since it does
not have knowledge of the secret values, it can not derive the value
of the session key. This method thus allow to securely distribute
the security keys without having the AAA servers being aware of the
value of those keys. AAA servers are here used as certificate
authorities.
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11. Conclusions
The Diameter Mobile IPv6 application defined in this document allows
for support of authentication and authorization of IPv6 mobile nodes
roaming between different domains. In addition, it support key
distribution and mobility by optimizing these procedures. The
application defines also new enhanced features that introduce
flexibility in the definition of business models for service
providers and allow for different types of terminals.
This first version focuses on the different functionalities involved
in the support by the AAA infrastructure of inter domain roaming of
Mobile IPv6 nodes.
12. Security Considerations
The Diameter Mobile IPv6 application defined in this document does
not create new security breaches for the IPv6 MN and the foreign and
visited domain. On the contrary, it allows for an effective and
efficient MN authentication and authorization when roaming between
different domains.
Full Copyright Statement
Copyright (C) The Internet Society (2004). This document is subject
to the rights, licenses and restrictions 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
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Le, Patil, Perkins, Faccin [Page 30]
INTERNET-DRAFT Diameter Mobile IPv6 Application November 2004
13. References
[1] Pat R. Calhoun, Charles E. Perkins, "Diameter Mobile IPv4
Application" Internet draft, Internet Engineer Task Force,
November 2001
[2] Diffie, W. and Hellman, M., "New Directions ijn
Cryptography", IEEE Transactions on Information Theory,
Vol. IT-22, Nov. 1976, pp. 664-654
[3] Franck Le, Stefano M. Faccin, "Key distribution mechanisms
for Mobile IPv6" Internet draft, Internet Engineer Task
Force, February 2001
[4] David B. Johnson, Charles Perkins, "Mobility Support in
IPv6" Internet draft, Internet Engineer Task Force,
November 2001
[5] D. Harkins, D. Carrel, "The Internet Key Exchange (IKE)",
RFC 2409, Internet Engineer Task Force, November 1998
[6] Sarvar Patel, "Weaknesses of North American Wireless
Authentication Protocol", IEEE Personal Communications,
June 1997
[7] Pat R. Calhoun, Haseeb Akhtar, Jari Arkko, Erik Guttman,
Allan C. Rubens,Glen Zorn, "Diameter Base Protocol"
Internet draft, Internet Engineer Task Force, November 2001
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14. Authors' Addresses
Franck Le
Nokia Research Center
6000 Connection Drive
Irving, TX 75039
USA
Phone: +1 972 374-1256
E-mail: franck.le@nokia.com
Basavaraj Patil
Nokia Corporation
6000 Connection Drive
Irving, TX 75039
USA
Phone: +1 972-894-6709
E-Mail: basavaraj.patil@nokia.com
Charles E. Perkins
Nokia Research Center
313 Fairchild Drive
Mountain View, California 94043
USA
Phone: +1 650-625-2986
E-Mail: charles.perkins@nokia.com
Stefano M. Faccin
Nokia Research Center
6000 Connection Drive
Irving, TX 75039
USA
Phone: +1 972 894-4994
E-mail: stefano.faccin@nokia.com
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