Diameter Maintenance and J. Korhonen (ed.)
Extensions (DIME) TeliaSonera
Internet-Draft J. Bournelle
Intended status: Standards Track France Telecom R&D
Expires: July 27, 2007 H. Tschofenig
Siemens Networks GmbH & Co KG
C. Perkins
Nokia Research Center
K. Chowdhury
Starent Networks
January 23, 2007
Diameter Mobile IPv6: NAS <-> HAAA Support
draft-ietf-dime-mip6-integrated-02.txt
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Copyright Notice
Copyright (C) The IETF Trust (2007).
Abstract
A Mobile IPv6 node requires a Home Agent address, a home address, and
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a security association with its Home Agent before it can start
utilizing Mobile IPv6. RFC 3775 requires that some or all of these
parameters are statically configured. Ongoing Mobile IPv6
bootstrapping work aims to make this information dynamically
available to the Mobile Node. An important aspect of the Mobile IPv6
bootstrapping solution is to support interworking with existing
authentication, authorization and accounting infrastructure. This
document describes the MIPv6 bootstrapping using the Diameter Network
Access Server (NAS) <-> home Authentication, Authorization and
Accounting server (HAAA) interface.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology and Abbreviations . . . . . . . . . . . . . . . . 4
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Commands, AVPs and Advertising Application Support . . . . . . 7
4.1. Advertising Application Support . . . . . . . . . . . . . 7
4.2. Command Codes . . . . . . . . . . . . . . . . . . . . . . 7
4.3. Diameter-EAP-Request (DER) . . . . . . . . . . . . . . . . 7
4.4. Diameter-EAP-Answer (DEA) . . . . . . . . . . . . . . . . 8
4.5. AA-Request (AAR) . . . . . . . . . . . . . . . . . . . . . 9
4.6. AA-Answer (AAA) . . . . . . . . . . . . . . . . . . . . . 10
4.7. Attribute Value Pair Definitions . . . . . . . . . . . . . 11
4.7.1. MIP6-Home-Agent-Address AVP . . . . . . . . . . . . . 11
4.7.2. MIP6-Home-Agent-FQDN AVP . . . . . . . . . . . . . . . 11
4.7.3. MIP6-Home-Link-Prefix AVP . . . . . . . . . . . . . . 12
4.7.4. MIP4-Home-Agent-Address AVP . . . . . . . . . . . . . 12
4.7.5. MIP6-Home-Address AVP . . . . . . . . . . . . . . . . 12
4.8. Capability Advertisement . . . . . . . . . . . . . . . . . 12
5. Diameter Client and Server Behavior During MIPv6
Bootstrapping . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1. Client (NAS) Behavior . . . . . . . . . . . . . . . . . . 13
5.2. Server Behavior . . . . . . . . . . . . . . . . . . . . . 14
6. Example Message Flows . . . . . . . . . . . . . . . . . . . . 15
6.1. EAP-based authentication . . . . . . . . . . . . . . . . . 15
6.2. Integrated scenario and HA allocation in MSP . . . . . . . 16
6.3. Integrated scenario and HA allocation in ASP . . . . . . . 18
7. AVP Occurrence Tables . . . . . . . . . . . . . . . . . . . . 19
7.1. DER and DEA Commands AVP Table . . . . . . . . . . . . . . 19
7.2. AAR and AAA Commands AVP Table . . . . . . . . . . . . . . 20
8. MIPv6 Bootstrapping NAS - HAAA Interface AVPs . . . . . . . . 21
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
10. Security Considerations . . . . . . . . . . . . . . . . . . . 22
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 22
12. Revision history . . . . . . . . . . . . . . . . . . . . . . . 23
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
13.1. Normative References . . . . . . . . . . . . . . . . . . . 23
13.2. Informative References . . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 25
Intellectual Property and Copyright Statements . . . . . . . . . . 27
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1. Introduction
The Mobile IPv6 (MIPv6) specification [RFC3775] requires a Mobile
Node (MN) to perform registration with a Home Agent (HA) with
information about its current point of attachment (Care-of Address).
The HA creates and maintains binding between the MN's Home Address
and the MN's Care-of Address.
In order to register with a HA, the MN needs to know some information
such as, the Home Link prefix, the HA address, the Home Address(es),
the Home Link prefix Length and security association related
information.
The aforementioned set of information may be statically provisioned
in the MN. However, static provisioning of this information becomes
easily provisioning and network administratiOn burden for an
operator. Moreover, static provisioning does not address load
balancing, failover, opportunistic home link assignment and assigment
of local home agents in close proximity to the MN. Also the ability
to react on sudden environmental or topological changes is minimal.
In a light of above issues static provisioning may not be desirable.
Dynamic assignment of MIPv6 home registration information is a
desirable feature for ease of deployment and network maintenance.
For this purpose, the AAA infrastructure, which is used for access
authentication, can be leveraged to assign some or all of the
necessary parameters. The Diameter server in Access Service
Provider's (ASP) or in Mobility Service Provider's (MSP) network may
return these parameters to the AAA client. Regarding the
bootstrapping procedures, the AAA client might either be the NAS, in
case of the integrated scenario, or the HA, in case of the split
scenario [I-D.ietf-mip6-bootstrapping-split]. The terms integrated
and split are described in the terminology section and were
introduced in [RFC4640] and [I-D.ietf-mip6-aaa-ha-goals].
2. Terminology and Abbreviations
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC2119 [RFC2119].
General mobility terminology can be found in [RFC3753]. The
following additional terms, as defined in [RFC4640], are used in this
document:
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Access Service Authorizer (ASA):
A network operator that authenticates a MN and establishes the
MN's authorization to receive Internet service.
Access Service Provider (ASP):
A network operator that provides direct IP packet forwarding to
and from the MN.
Mobility Service Authorizer (MSA):
A service provider that authorizes MIPv6 service.
Mobility Service Provider (MSP):
A service provider that provides MIPv6 service. In order to
obtain such service, the MN must be authenticated and authorized
to obtain the MIPv6 service.
Split scenario:
A scenario where the mobility service and the network access
service are authorized by different entities.
Integrated Scenario:
A scenario where the mobility service and the network access
service are authorized by the same entity.
Network Access Server (NAS):
A device that provides an access service for a user to a network.
Home AAA (HAAA):
An authentication, authorization and accounting server located in
user's home network.
3. Overview
This document addresses the authentication, authorization and
accounting functionality required by for the MIPv6 bootstrapping as
outlined in the MIPv6 bootstrapping problem statement document
[RFC4640]. This document focuses on the Diameter based AAA
functionality for the NAS - HAAA interface.
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In the integrated scenario MIPv6 bootstrapping is provided as part of
the network access authentication procedure. Figure 1 shows the
participating entities. This document, however, only concentrates on
the NAS, possible local Diameter proxies and the home Diameter
server.
+---------------------------+ +-----------------+
|Access Service Provider | |ASA/MSA/(MSP) |
|(Mobility Service Provider)| | |
| | | |
| +--------+ | | +--------+ |
| |Local | Diameter | | |Home | |
| |Diameter|<---------------------->|Diameter| |
| |Proxy | | | |Server | |
| +--------+ | | +--------+ |
| ^ ^ | | ^ |
| | | | | | |
| | | | | | |
| Diameter | | v |
| | | +-------+ | | +-------+ |
| | | |Home | | | |Home | |
| | +-------->|Agent | | | |Agent | |
| | |in ASP | | | |in MSP | |
| v +-------+ | | +-------+ |
+-------+ IEEE | +-----------+ +-------+ | +-----------------+
|Mobile | 802.1X | |NAS/Relay | |DHCPv6 | |
|Node |------------|Diameter |---|Server | |
| | PANA,... | |Client | | | |
+-------+ DHCP | +-----------+ +-------+ |
+---------------------------+
Figure 1: Mobile IPv6 Bootstrapping in the Integrated Scenario
In a typical MIPv6 access scenario the MN is attached to an ASP's
network. During the network attachment procedure, the NAS/Diameter
client interacts with the MN.
During the time of authentication the Diameter server in the MSA
detects that the user is also authorized for MIPv6 access. Based on
the MSA's policy, the Diameter server may return several MIPv6
bootstrapping related parameters.
Depending on the details of the bootstrapping solution interaction
with the DHCPv6 server may be required, as described in
[I-D.ietf-mip6-bootstrapping-integrated-dhc]. However, the Diameter
based NAS - HAAA interface described in this document is not tied to
DHCPv6 as the only possible MIPv6 bootstrapping method.
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4. Commands, AVPs and Advertising Application Support
This section describes command codes, defines AVPs and advertised
application identifiers for the Diameter MIPv6 bootstrapping in the
NAS - HAAA interface.
4.1. Advertising Application Support
Diameter nodes conforming to this specification SHOULD include the
value of 1 (NASREQ application) or 5 (EAP application) in the Auth-
Application-Id or the Acct-Application-Id AVP in the Capabilities-
Exchange-Request and Capabilities-Exchange-Answer commands [RFC3588].
4.2. Command Codes
This document re-uses the Diameter NASREQ application [RFC4072] and
the EAP application commands [RFC4005]. The following commands are
used to carry MIPv6 related bootstrapping AVPs:
Command-Name Abbrev. Code Reference Application
Diameter-EAP-Request DER 268 RFC 4072 EAP
Diameter-EAP-Answer DEA 268 RFC 4072 EAP
AA-Request AAR 265 RFC 4005 NASREQ
AA-Answer AAA 265 RFC 4005 NASREQ
Figure 2: MIPv6 Bootstrapping NAS - HAAA Interface Command Codes
When the Re-Auth-Request (RAR), Re-Auth-Answer (RAA), Session-
Termination-Request (STR), Session-Termination-Answer (STA), Abort-
Session-Request (ASR), Abort-Session-Answer (ASA), Accounting-Request
(ACR), and Accounting-Answer (ACA) commands are used together with
the MIPv6 bootstrapping NAS - HAAA interface, they follow the rules
in the Diameter NASREQ [RFC4005], EAP [RFC4072] and RFC 3588
[RFC3588] applications. The accounting commands use the Application
Identifier value of 3 (Diameter Base Accounting); the others use 0
(Diameter Common Messages).
4.3. Diameter-EAP-Request (DER)
The Diameter-EAP-Request (DER) command [RFC4072], indicated by the
Command-Code field set to 268 and the 'R' bit set in the Command
Flags field, may be sent by the NAS to the Diameter server providing
network access authentication and authorization services. At the
same time with the network access authentication and authorization
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the NAS MAY indicate the access network capability of MIPv6
bootstrapping and optionally also the capability of a local HA
assignment.
The message format is the same as defined in [RFC4072] with an
addition of optional MIPv6 bootstrapping NAS - HAAA interface AVPs to
indicate capabilities of the NAS and the ASP:
<Diameter-EAP-Request> ::= < Diameter Header: 268, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Auth-Request-Type }
[ MIP6-Home-Agent-Address ]
[ MIP6-Home-Agent-FQDN ]
[ MIP6-Home-Link-Prefix ]
[ MIP6-Home-Address ]
[ MIP4-Home-Agent-Address ]
[ Destination-Host ]
...
* [ AVP ]
Figure 3: Diameter EAP Request Command
4.4. Diameter-EAP-Answer (DEA)
The Diameter-EAP-Answer (DEA) message define in [RFC4072], indicated
by the Command-Code field set to 268 and 'R' bit cleared in the
Command Flags field is sent in response to the Diameter-EAP-Request
message (DER). If the network access authentication procedure was
successful then the response MAY include any set of MIP6-Home-Agent-
Address AVP, MIP6-Home-Link-Prefix, MIP6-Home-Agent-FQDN, MIP6-Home-
Address and MIP4-Home-Agent-address AVPs.
The message format is the same as defined in [RFC4072] with an
addition of optional MIPv6 bootstrapping NAS - HAAA AVPs:
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<Diameter-EAP-Answer> ::= < Diameter Header: 268, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Request-Type }
{ Result-Code }
{ Origin-Host }
{ Origin-Realm }
[ MIP6-Home-Agent-Address ]
[ MIP6-Home-Agent-FQDN ]
[ MIP6-Home-Link-Prefix ]
[ MIP6-Home-Address ]
[ MIP4-Home-Agent-Address ]
[ User-Name ]
...
* [ AVP ]
Figure 4: Diameter EAP Answer Command
4.5. AA-Request (AAR)
The AA-Request (AAR) message, indicated by the Command-Code field set
to 265 and 'R' bit set in the Command Flags field, may be sent by the
NAS to the Diameter server providing network access configuration
services. At the same time with the network access configuration the
NAS MAY request HA assignment, to authorize for mobility service
usage and optionally to indicate the support of possible local HA
assignment.
The message format is the same as defined in [RFC4005] with an
addition of optional MIPv6 bootstrapping NAS - HAAA AVPs:
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<AA-Request> ::= < Diameter Header: 265, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Auth-Request-Type }
[ MIP6-Home-Agent-Address ]
[ MIP6-Home-Agent-FQDN ]
[ MIP6-Home-Link-Prefix ]
[ MIP6-Home-Address ]
[ MIP4-Home-Agent-Address ]
[ Destination-Host ]
...
* [ AVP ]
Figure 5: AA Request Command
4.6. AA-Answer (AAA)
The AA-Answer (AAA) message, indicated by the Command-Code field set
to 265 and 'R' bit cleared in the Command Flags field is sent in
response to the AA-Request (AAR) message for confirmation of the
result of MIPv6 HA bootstrapping. If the network access
authentication procedure was successful then the response MAY include
any set of MIP6-Home-Agent-Address AVP, MIP6-Home-Link-Prefix, MIP6-
Home-Agent-FQDN, MIP6-Home-Address and MIP4-Home-Agent-address AVPs.
The message format is the same as defined in [RFC4005] with an
addition of optional MIPv6 bootstrapping NAS - HAAA interface AVPs:
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<AA-Answer> ::= < Diameter Header: 265, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Request-Type }
{ Result-Code }
{ Origin-Host }
{ Origin-Realm }
[ MIP6-Home-Agent-Address ]
[ MIP6-Home-Agent-FQDN ]
[ MIP6-Home-Link-Prefix]
[ MIP6-Home-Address ]
[ MIP4-Home-Agent-address ]
[ User-Name ]
...
* [ AVP ]
Figure 6: AA Answer Command
4.7. Attribute Value Pair Definitions
4.7.1. MIP6-Home-Agent-Address AVP
The MIP6-Home-Agent-Address AVP (AVP Code TBD) is of type OctetString
and contains the MIPv6 HA address and the prefix length of the said
address. The AVP is a discriminated union, representing IPv6 address
in network byte order. The first two octets of this AVP represents
the home link prefix length followed by 16 octets of the IPv6
address.
The Diameter server MAY decide to assign a MIPv6 HA to the MN that is
in close proximity to the point of attachment (e.g. determined by the
NAS-Identifier). There may be other reasons for dynamically
assigning HAs to the MN, for example to share the traffic load. The
AVP also contains the prefix length so that the MN can easily infer
one of the possible Home Link prefixes from the HA address.
This AVP MAY also be sent by the NAS to the Diameter server in a
request message as a hint to suggest a dynamic HA may be assigned to
the MN. Based on local policy information the Diameter server may
decide to follow the hint or to override this suggestion with its
preferred HA IP address.
4.7.2. MIP6-Home-Agent-FQDN AVP
The MIP6-Home-Agent-FQDN AVP (AVP Code TBD) is of type UTF8String and
contains the FQDN of a MIPv6 HA. The usage of this AVP is equivalent
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to the MIP6-Home-Agent-Address AVP except that the host using the
FQDN needs to perform a DNS query in order to discover the HA
address.
4.7.3. MIP6-Home-Link-Prefix AVP
The MIP6-Home-Link-Prefix AVP (AVP Code TBD) is of type OctetString
and contains the MIPv6 home link prefix. There may be reasons for
the Diameter server to dynamically assigning home link prefix to the
MN, for example one that is in close proximity to the point of
attachment.
The MN can perform RFC 3775 [RFC3775] specific procedures to discover
other information for MIPv6 registration.
4.7.4. MIP4-Home-Agent-Address AVP
The MIP4-Home-Agent-Address AVP (AVP Code TBD) is of type OctetString
and contains the IPv4 HA address and the prefix length of the said
address. The AVP is a discriminated union, representing IPv4 address
in network byte order. The first two octets of this AVP represents
the home link prefix length followed by 4 octets of the IPv4 address.
The Diameter server MAY decide to assign a MIPv4 HA to the MN in a
case where dual stack Mobile IP is supported
[I-D.ietf-mip6-nemo-v4traversal].
4.7.5. MIP6-Home-Address AVP
The MIP6-Home-Address AVP (AVP Code TBD) is of type OctetString and
contains the MIPv6 Home Address and the prefix length of the said
address. The AVP is a discriminated union, representing IPv6 address
in network byte order. The first two octets of this AVP represents
the Home Address prefix length followed by 16 octets of the IPv6
address.
The Diameter server MAY assign a home address to the MN. This allows
the network operator to support MNs that are not configured with
static addresses. The attribute also contains the prefix length so
that the MN can easily infer the home link prefix from the HA
address.
4.8. Capability Advertisement
The NAS/ASP may include any MIPv6 bootstrapping AVPs in the DER or
AAR messages in order to advertise its MIPv6 bootstrapping
capabilities to the Diameter server. This capability advertisement
may also be used to propose locally allocated mobility agents,
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locally allocated prefix or home address to the Diameter server. As
an example the MIP6-Home-Agent-Address AVP could contain the IP
address of the locally allocated HA.
If the MIP6-Home-Agent-Address AVP is only used as a MIPv6
bootstrapping capability indicator then the IP address MUST be set to
unspecified address (::/128). The MIP6-Home-Agent-FQDN AVP SHOULD
NOT be used for the capability advertisement if it does not name a
locally allocated HA.
5. Diameter Client and Server Behavior During MIPv6 Bootstrapping
This section describes the Diameter server and client behavior in
case of the MIPv6 bootstrapping in the integrated scenario. The text
makes several assumptions.
o The Diameter server supports at least the Diameter BASE, EAP and
NASREQ applications.
o The Diameter client (i.e., the NAS) supports at least the Diameter
BASE, EAP and NASREQ applications.
o The MN uses such network access authentication method and
credentials that are supported by the NAS/ASP and ASA/MSA.
o The MN has been provisioned with a MIPv6 service.
5.1. Client (NAS) Behavior
If the ASP/NAS does not support MIPv6 integrated scenario
bootstrapping then the NAS either selects the basic Diameter NASREQ
or EAP application depending on which authentication method gets
used. Naturally after a successful or a failed authentication the
NAS does not have to carry out any MIPv6 bootstrapping related
procedures.
Next, we describe two different scenarios for the network access
authentication when the ASP/NAS supports MIPv6 integrated scenario
bootstrapping.
1) The MN uses some EAP-based method for network access
authentication. In this scenario the NAS uses commands originally
defined for the EAP application.
2) The MN uses a non-EAP-based network access authentication
procedure. In this scenario the NAS uses the Diameter NASREQ
application commands.
The NAS may include the MIPv6 NAS - HAAA AVPs in the DER or in the
AAR messages. This serves two purposes. Firstly the NAS/ASP may
advertise its MIPv6 bootstrapping capability to the Diameter server.
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Secondly the NAS/ASP may suggest locally allocated HAs to the
Diameter server. Whether the locally allocated HAs are allowed for
the forthcoming MIPv6 session depends on the MN's subscription and
the ASA/MSA(/MSP) policies. If the NAS/ASP only wants to advertise
its capability for local agent allocation but does not want to
provide any specific agent at this point of time (e.g. that is left
for later steps during the actual Mobile IP registration) the AVPs
MUST contain values described in Section 4.8.
If the network access authentication failed the NAS receives
appropriate error codes as defined for the Diameter EAP or NASREQ
applications. The NAS does not allow the MN to access the network
and does not do any MIPv6 bootstrapping related procedures.
If the network access authentication completed successfully, the NAS
looks for HA defining AVPs in the reply messages (either DEA or AAA
depending on the used authentication method). The NAS associates the
received bootstrapping information to the MN that initiated the
access authentication and stores the information internally (storing
time is determined by the ASP policy). The stored bootstrapping
information is then available for the NAS and the DHCP relay for
later step during the MN bootstrapping process.
The actual bootstrapping from the MN point of view takes place after
the network access authentication has completed. The bootstrapping
may be realized e.g. using DHCP as defined in
[I-D.ietf-mip6-bootstrapping-integrated-dhc] and [RFC2132].
The MN has no consistent way of indicating to the NAS that it
supports MIPv6 integrated scenario way of bootstrapping during the
network access authentication. Subsequently the NAS has no
possibilities to find out whether the terminal attempting to
authenticate is actually a MN with MIPv6 bootstrapping functionality
prior the network access authentication has completed. Thus, it is
possible that the NAS initiates MIPv6 integrated scenario
bootstrapping configuration even if the MN is not able to make any
use of it later. The Diameter server in the ASA/MSA might be able to
detect this situation during the authentication phase based on the
information in the subscriber database assuming the ASA is able to
verify whether the MN has been provisioned with a MIPv6 service (from
the MSA/MSP).
5.2. Server Behavior
If the NAS/ASP does not support MIPv6 integrated scenario
bootstrapping then the NAS either selects the Diameter NASREQ or EAP
application depending on which access authentication method the MN
has to use to authenticate. In this case the NAS does not either
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include any MIPv6 NAS - HAAA interface AVPs as a hint of the
bootstrapping capability in the NAS/ASP. The Diameter server in the
ASA/MSA(/MSP) detects this case (based on AVPs that serve as a
capability hint) and does not have to carry out any MIPv6
bootstrapping related procedures. However, as the capability
advertisement mechanism described in this document serves only as an
optional hint, the Diameter server should not entirely rely on the
received capability hints but also base its working logic on
subscription information and general MSA(/MSP) policies.
Next we describe two different scenarios for the network access
authentication when the NAS/ASP supports MIPv6 integrated scenario
bootstrapping.
1) The MN uses some EAP-based method to authenticate to the network
and the NAS uses Diameter EAP application commands. Depending on
the ASA/MSA(/MSP) policy the Diameter server SHOULD assign a MIPv6
HA to the MN and include corresponding MIP6-Home-Agent-Address,
the MIP6-Home-Agent-FQDN AVPs and the MIP6-Home-Link-Prefix in the
final DEA message.
2) The MN uses some other than EAP-based method to authenticate to
the network and the NAS uses Diameter NASREQ application commands.
Depending on the ASA/MSA(/MSP) policy the Diameter server SHOULD
assign a MIPv6 HA to the MN and include corresponding MIP6-Home-
Agent-Address, the MIP6-Home-Agent-FQDN AVPs and the MIP6-Home-
Link-Prefix in the final AAA message.
If the Diameter request message contained any MIPv6 NAS -HAAA
interface AVPs the Diameter server should regard them as a hint of
the MIPv6 bootstrapping capability in the NAS/ASP. Any of these AVPs
may contain values as described in Section 4.8 which indicate the
NAS/ASP would like to locally allocate a HA or a home link to the MN.
The Diameter server may or may not honor the NAS/ASP hint based on
the MN's subscription and ASA/MAS(/MSP) policies.
6. Example Message Flows
6.1. EAP-based authentication
This section shows basic message flows of MIPv6 integrated scenario
bootstrapping and dynamic HA assignment. In the Figure 7 network
access authentication is based on EAP (e.g. 802.11i/802.1X). The NAS
informs the home Diameter server that HA assignment in the foreign
network is possible. The Diameter server assigns the MN a HA either
in the home MSP or in the ASP. The assignment procedure is out of
scope of this document. The Diameter server then replies to the NAS
with HA related bootstrapping information.
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NAS Local proxy Home server
| | |
| Diameter-EAP-Request | |
| MIP6-Home-Agent-Address(IPv6 address) |
| MIP6-Home-Agent-FQDN=visited_ha6.example.com |
| MIP4-Home-Agent-Address(IPv4 address) |
| MIP6-Home-Link-Prefix(IPv6 prefix) |
| MIP6-Home-Address(IPv6 address) |
| Auth-Request-Type=AUTHORIZE_AUTHENTICATE |
| EAP-Payload(EAP Start) | |
|------------------------------->|------------------------------->|
| | |
| : |
: ...more EAP Request/Response pairs... :
| : |
| | |
| | Diameter-EAP-Answer |
| MIP6-Home-Agent-Address(IPv6 address) |
| MIP6-Home-Agent-FQDN=ha.example.com |
| MIP6-Home-Address(IPv6 address) |
| | Result-Code=DIAMETER_SUCCESS |
| | EAP-Payload(EAP Success) |
| | EAP-Master-Session-Key |
| | (authorization AVPs) |
| | ... |
|<-------------------------------|<-------------------------------|
| | |
Figure 7: MIPv6 integrated scenario bootstrapping and NAS - HAAA
interface example when EAP is used for access authentication
6.2. Integrated scenario and HA allocation in MSP
Diameter is used to authenticate and authorize the MN for the
mobility service, and to send information about the allocated HA to
the NAS. In this example scenario the MN uses DHCP for its IP
address configuration.
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|
--------------ASP------>|<--ASA/MSA/(MSP)--
|
+----+ +--------+ +-------+ +--------+
| | |Diameter| | | | |
| | | Client | | | | |
| MN | | NAS/ | | DHCP | | Home |
| | | DHCP | | Server| |Diameter|
| | | Relay | | | | Server |
+-+--+ +----+---+ +---+---+ +--------+
| | | |
| 1 | 2 | |
|<------------->|<----------------------->|
| | | |
| | | |
| 3 | | |
|-------------->| | |
| | | |
| | 4 | |
| |------------>| |
| | | |
| | 5 | |
| |<------------| |
| | | |
| 6 | | |
|<--------------| | |
| | | |
Figure 8: HA allocation in MSP
1) The MN executes the normal network access authentication procedure
(IEEE 802.11i/802.1X, PANA, ...) with the NAS. The NAS acts as an
authenticator in "pass-through" mode. The other endpoint of the
authentication dialogue is the MN's home Diameter server. This is
a typical scenario for e.g. EAP-based authentication methods.
The NAS includes at least one of the NAS-HAAA interface AVPs in
the DER or in the AAR messages to indicate MIPv6 bootstrapping
capability. For example the NAS could include MIP6-Home-Agent-
Address AVP with 0::/128 as the HA address (the NAS has no
particular HA to propose to the Diameter server).
2) Depending on the Diameter server configuration and the
subscription profile, the MIP6-Home-Agent-Address AVP or the MIP6-
Home-Agent-FQDN AVP may be appended to the DEA or to the AAA
message, assuming the home Diameter server knows or has allocated
a HA to the MN. In case the MIP6-Home-Agent-FQDN AVP was returned
the MN ultimately needs to perform a DNS query in order to
discover the HA address. For example the home Diameter server
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could return the following AVPs:
o MIP6-Home-Agent-Address = 2001:2001:6000:302::1/64
o MIP6-Home-Address = 2001:2001:6000:302::dead:beef/64
o MIP6-Home-Link-Prefix = 2001:2001:6000:302::/64
3) the MN sends a DHCPv6 Information Request message to
all_DHCP_Relay_Agents_and_Servers address. In the OPTION_ORO,
Option Code for the Home Network Identifier Option shall be
included in that message
[I-D.ietf-mip6-bootstrapping-integrated-dhc]. The Home Network
Identifier Option should have id-type of 1, the message is a
request to discover home network information that pertains to the
given realm, i.e., the user's home domain (identified by the NAI
of the MN). The OPTION_CLIENTID is set by the MN to identify
itself to the DHCP server.
Steps 4 to 6 are not relevant in NAS-HAAA Diameter interface point of
view and are not described in this document. Refer
[I-D.ietf-mip6-bootstrapping-integrated-dhc] for detailed information
about the rest of the integrated scenario bootstrapping procedure.
6.3. Integrated scenario and HA allocation in ASP
This scenario is similar to the one described in Section 6.2 and
illustrated in Figure 8. There are slight differences in steps 2)
and 3).
2) The NAS/ASP has allocated a local HA (e.g. with IP address 2001:
788:1:c020::1/64) and a local prefix, and proposes those to MN's
home Diameter server. For example the NAS includes following AVPs
in the DER or in the AAR messages:
o MIP6-Home-Agent-Address = 2001:788:1:c020::1/64
o MIP6-Home-Link-Prefix = 2001:788:1:c020::/64
Depending on the Diameter server configuration and the
subscription profile, the Diameter server either accepts or
rejects the HA IP address (or FQDN) proposed by the NAS/ASP. If
the Diameter server accepts the proposed HA the AVP containing the
HA information is returned as is back to the NAS. In this example
the returned IP6-Home-Agent-Address AVP would contain the same
2001:788:1:c020::1/64 IP address value. On the orher hand if the
Diameter server does not accept the proposed HA, the Diameter
server overwrites the MIP6-Home-Agent-Address AVP value with an IP
address of the preferred HA (e.g. 2001:2001:6000::1/64) and
returns the new IP address back to the NAS/ASP (the MIP6-Home-
Agent-FQDN AVP is handled in the same way when present). This is
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also an indication to the NAS/ASP that locally allocated HAs are
not to be used. In a case when the home Diameter server accepted
the NAS/ASP proposed local HA the home Diameter server would
return e.g. the following AVPs:
o MIP6-Home-Agent-Address = 2001:788:1:c020::1/64
o MIP6-Home-Link-Prefix = 2001:788:1:c020::/64
3) The type-id field in the Home Network Identifier Option is set to
zero, indicating that a HA is requested in the ASP instead of in
the MSP. Depending on the result of the phase 2) the DHCP relay
agent places in the OPTION_MIP6-RELAY-Option either the locally
allocated HA information or the HA information that was returned
(overwritten) by home Diameter server.
7. AVP Occurrence Tables
7.1. DER and DEA Commands AVP Table
The following table lists the additional MIPv6 bootstrapping NAS -
HAAA interface AVPs that optionally may be present in the DER and DEA
Commands, as defined in this document and in [RFC4072].
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+---------------+
| Command-Code |
|-------+-------+
Attribute Name | DER | DEA |
-------------------------------+-------+-------+
MIP6-Home-Agent-Address [ab] | 0-1 | 0-1 |
MIP6-Home-Agent-FQDN [ab] | 0-1 | 0-1 |
MIP4-Home-Agent-Address | 0-1 | 0-1 |
MIP6-Home-Link-Prefix [cd] | 0-1 | 0-1 |
MIP6-Home-Address [cd] | 0-1 | 0-1 |
+-------+-------+
Notes:
[a] Either MIP6-Home-Agent-Address or MIP6-Home-Agent-FQDN
MAY appear in DER or DEA Commands.
[b] If the Diameter server accepts the NAS suggestion for
the HA, then the Diameter server MUST also include the
values received in these AVPs in the DEA Command.
[c] Either MIP6-Home-Link-Prefix or MIP6-Home-Address MAY
appear in DER or DEA Commands.
[d] If either MIP6-Home-Agent-Address or MIP6-Home-Agent-FQDN
are present in DER Command then this AVP MUST also be
included in the corresponding DER Command. If the Diameter
server accepts the NAS suggestion for the HA then the
Diameter server MUST also include the value received in
this AVP in the DEA Command.
Figure 9: DER and DEA Commands AVP Table
7.2. AAR and AAA Commands AVP Table
The following table lists the additional MIPv6 bootstrapping NAS -
HAAA interface AVPs that may optionally be present in the AAR and AAA
Commands, as defined in this document and in [RFC4005].
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+---------------+
| Command-Code |
|-------+-------+
Attribute Name | AAR | AAA |
-------------------------------|-------+-------|
MIP6-Home-Agent-Address [ab] | 0-1 | 0-1 |
MIP6-Home-Agent-FQDN [ab] | 0-1 | 0-1 |
MIP4-Home-Agent-Address | 0-1 | 0-1 |
MIP6-Home-Link-Prefix [cd] | 0-1 | 0-1 |
MIP6-Home-Address [cd] | 0-1 | 0-1 |
+-------+-------+
Notes:
[a] Either MIP6-Home-Agent-Address or MIP6-Home-Agent-FQDN
MAY appear in AAR or AAA Commands.
[b] If the Diameter server accepts the NAS suggestion for
the HA, then the Diameter server MUST also include the
values received in these AVPs in the AAA Command.
[c] Either MIP6-Home-Link-Prefix or MIP6-Home-Address MAY
appear in AAR or AAA Commands.
[d] If either MIP6-Home-Agent-Address or MIP6-Home-Agent-FQDN
are present in AAR Command then this AVP MUST also be
included in the corresponding AAR Command. If the Diameter
server accepts the NAS suggestion for the HA then the
Diameter server MUST also include the value received in
this AVP in the AAA Command.
Figure 10: AAR and AAA Commands AVP Table
8. MIPv6 Bootstrapping NAS - HAAA Interface AVPs
This section defines the AVPs that are specific to Diameter MIPv6
bootstrapping NAS - HAAA interface and MAY be included in the
Diameter EAP [RFC4072] and the NASREQ [RFC4005] applications messages
listed in Section 4 of this document. The Diameter AVP rules are
defined in the Diameter Base [RFC3588], Section 4. These AVP rules
are observed in AVPs defined in this section.
The following table describes the Diameter AVPs, their AVP Code
values, types, possible flag values, and whether the AVP MAY be
encrypted. The Diameter base [RFC3588] specifies the AVP Flag rules
for AVPs in section 4.5.
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+---------------------+
| AVP Flag rules |
+----+-----+----+-----+----+
AVP Section | | |SHLD|MUST | |
Attribute Name Code Defined Data Type |MUST| MAY |NOT |NOT |Encr|
-----------------------------------------+----+-----+----+-----+----+
MIP6-Home-Agent- TBD 4.7.1 OctetString| | P | | M,V | Y |
Address | | | | | |
MIP6-Home-Agent- TBD 4.7.2 UTF8String | | P | | M,V | Y |
FQDN | | | | | |
MIP4-Home-Agent- TBD 4.7.4 OctetString| | P | | M,V | Y |
address | | | | | |
MIP6-Home-Link- TBD 4.7.3 Unsigned32 | | P | | M,V | Y |
Prefix | | | | | |
MIP6-Home-Address TBD 4.7.5 OctetString| | P | | M,V | Y |
-----------------------------------------+----+-----+----+-----+----+
Figure 11: AVP Flag Rules Table
9. IANA Considerations
This specification defines the following new AVPs:
MIP6-Home-Agent-Address is set to TBD
MIP6-Home-Agent-FQDN is set to TBD
MIP4-Home-Agent-Address is set to TBD
MIP6-Home-Link-Prefix is set to TBD
MIP6-Home-Address is set to TBD
10. Security Considerations
The security considerations for the Diameter interaction required to
accomplish the integrated scenario are described in
[I-D.ietf-mip6-bootstrapping-integrated-dhc] . Additionally, the
security considerations of the Diameter base protocol [RFC3588],
Diameter NASREQ application [RFC4005] / Diameter EAP [RFC4072]
application (with respect to network access authentication and the
transport of keying material) are applicable to this document.
11. Acknowledgements
This document is heavily based on the ongoing work for RADIUS MIPv6
interaction. Hence, credits go to respective authors for their work
with draft-ietf-mip6-radius-00.txt. Furthermore, the author would
like to thank the authors of draft-le-aaa-diameter-mobileipv6-04.txt
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(Franck Le, Basavaraj Patil, Charles E. Perkins, Stefano Faccin) for
their work in context of MIPv6 Diameter interworking. Their work
influenced this document. Julien Bournelle would like to thank GET/
INT since he began to work on this document while he was in their
employ.
12. Revision history
The following changes were made to the -01 version of the draft:
o The document title was changed to "The NAS - HAAA Interface for
MIPv6 Bootstrapping".
o Added HAAA and NAS to terminology section".
o Changed NAS application to NASREQ application.".
o Changed "Integrated Scenario" to NAS-HAAA interface".
o The separate Diameter Application-ID for MIPv6 bootstrapping
(MIP6BSTI) got removed and all bootstrapping is based on Diameter
EAP application and Diameter NAS application.
o MIPv6-Bootstrapping-Feature AVP was removed and General text
regarding to the capability advertisement based on optional AVPs
was added.
o The capability exchange was modified so that the NAS may suggest a
specific HA to the AAAH. Original MIPv6-Bootstrapping-Feature AVP
was replaces with a possibility to include any bootstrapping AVP
to the Diameter AAR or DER messages as a capability and local
allocation hint.
The following changes were made to the -02 version of the draft:
o Section 7 NAS - HAAA Interface AVPs flags were corrected. 'M'
flag was listed as MUST even if it should have been MUST NOT.
o General shortening of the text.
o Addition of the MIP6-Home-Address AVP.
o Checked against draft-ietf-mip6-radius-01.
o Addition of noted & constrains to AVP tables.
o Miscellaneous corrections like Mobile IPv6 -> MIPv6.
o Added signaling examples for HA assignment from MSP, and local HA
assignment.
13. References
13.1. Normative References
[I-D.ietf-mip6-aaa-ha-goals]
Giaretta, G., "AAA Goals for Mobile IPv6",
draft-ietf-mip6-aaa-ha-goals-03 (work in progress),
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September 2006.
[I-D.ietf-mip6-bootstrapping-integrated-dhc]
Chowdhury, K. and A. Yegin, "MIP6-bootstrapping via DHCPv6
for the Integrated Scenario",
draft-ietf-mip6-bootstrapping-integrated-dhc-01 (work in
progress), June 2006.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", March 1997.
[RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.
Arkko, "Diameter Base Protocol", RFC 3588, September 2003.
[RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
in IPv6", RFC 3775, June 2004.
[RFC4640] Patel, A. and G. Giaretta, "Problem Statement for
bootstrapping Mobile IPv6 (MIPv6)", RFC 4640,
September 2006.
13.2. Informative References
[I-D.ietf-mip6-bootstrapping-split]
Giaretta, G., "Mobile IPv6 bootstrapping in split
scenario", draft-ietf-mip6-bootstrapping-split-04 (work in
progress), December 2006.
[I-D.ietf-mip6-nemo-v4traversal]
Soliman, H., "Mobile IPv6 support for dual stack Hosts and
Routers (DSMIPv6)", draft-ietf-mip6-nemo-v4traversal-03
(work in progress), October 2006.
[RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, March 1997.
[RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology",
RFC 3753, June 2004.
[RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton,
"Diameter Network Access Server Application", RFC 4005,
August 2005.
[RFC4072] Eronen, P., Hiller, T., and G. Zorn, "Diameter Extensible
Authentication Protocol (EAP) Application", RFC 4072,
August 2005.
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Authors' Addresses
Jouni Korhonen
TeliaSonera
Teollisuuskatu 13
Sonera FIN-00051
Finland
Email: jouni.korhonen@teliasonera.com
Julien Bournelle
France Telecom R&D
38-4O rue du general Leclerc
Issy-Les-Moulineaux 92794
France
Email: julien.bournelle@orange-ftgroup.com
Hannes Tschofenig
Siemens Networks GmbH & Co KG
Otto-Hahn-Ring 6
Munich, Bavaria 81739
Germany
Email: Hannes.Tschofenig@siemens.com
URI: http://www.tschofenig.com
Charles E. Perkins
Nokia Research Center
313 Fairchild Drive
Mountain View CA 94043
US
Phone: +1 650 625-2986
Email: charliep@iprg.nokia.com
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Kuntal Chowdhury
Starent Networks
30 International Place
Tewksbury MA 01876
US
Phone: +1 214 550 1416
Email: kchowdhury@starentnetworks.com
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Full Copyright Statement
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