Network Working Group Maria-Carmen Belinchon
INTERNET-DRAFT Miguel-Angel Pallares
Category: Standards Track Carolina Canales
Expires: May 2003 Ericsson
Peter J. McCann
Lucent
Jaakko Rajaniemi
Nokia
November, 2002
Diameter Multimedia Application
<draft-johansson-aaa-diameter-mm-app-02.txt>
Status of this memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that other
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The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/lid-abstracts.txt
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This document is an individual submission to the IETF. Comments
should be directed to the authors.
Abstract
This document specifies a Diameter application that allows to perform
the authentication, authorization, and collection of accounting
information for Session Initiation Protocol (SIP) services rendered
to a client node. This application, combined with the base Diameter
protocol and appropriate SIP extensions, allows SIP User Agents (UAs)
to obtain services from SIP servers that are connected to a Diameter
infrastructure. When combined with the Inter-Domain capability of
the base protocol, service may even be obtained from SIP servers that
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belong to foreign domains, as would be encountered by roaming mobile
nodes.
Note that the specification defined here may be used independently of
the authentication technique used for authenticating a node's link
layer or network-layer access. In particular, we do not require that
the client node was authenticated for access with the use of either
the Mobile IP [4] or NASREQ [3] Diameter application.
TABLE OF CONTENTS
1. Introduction.....................................................3
1.1 Requirements language...........................................4
2 Description of a SIP network architecture.........................4
2.1 User authentication by SSP......................................5
2.2 User authentication by AAA server...............................7
2.3 Invitation......................................................9
2.4 User Profile Updating...........................................9
2.5 User registration termination..................................10
3 Command Codes...................................................10
3.1 User-Authorization-Request (UAR) Command.......................10
3.2 User-Authorization-Answer (UAA) Command........................11
3.3 Server-Assignment-Request (SAR) Command........................11
3.4 Server-Assignment-Answer (SAA) Command.........................12
3.5 Location-Info-Request (LIR) Command............................13
3.6 Location-Info-Answer (LIA) Command.............................13
3.7 Multimedia-Auth-Request (MAR) Command..........................14
3.8 Multimedia-Auth-Answer (MAA) Command...........................14
3.9 Registration-Termination-Request (RTR) Command.................15
3.10 Registration-Termination-Answer (RTA) Command.................15
3.11 Push-Profile-Request (PPR) Command............................16
3.12 Push-Profile-Answer (PPA) Command.............................16
4 Result Code AVP values...........................................17
4.1 Success........................................................17
4.2 Permanent failures.............................................17
5 Diameter AVP values..............................................18
5.1 SIP-Server AVP.................................................18
5.1.1 SIP-Server-Name AVP..........................................18
5.1.2 SIP-Server-Capability AVP....................................18
5.1.2.1 Mandatory-Capability AVP...................................18
5.1.2.2 Optional -Capability AVP...................................19
5.2 SIP-Public-Identity AVP........................................19
5.3 SIP-Visited-Network-Identifier AVP.............................19
5.4 SIP-Server-Assignment-Type AVP.................................19
5.5 SIP-Auth-Data-Item AVP.........................................20
5.5.1 SIP-Item-Number AVP..........................................21
5.5.2 SIP-Authentication-Scheme AVP................................21
5.5.3 SIP-Authenticate AVP.........................................21
5.5.4 SIP-Authorization AVP........................................21
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5.5.5 SIP-Authentication-Info AVP..................................21
5.5.6 SIP-Authentication-Context AVP...............................21
5.6 SIP-Number-Auth-Items AVP......................................22
5.7 SIP-User-Data AVP..............................................22
5.8 NAS-Session-Key AVP............................................22
5.9 NAS-Key-Binding AVP............................................22
5.10 SIP-Deregistration-Reason AVP.................................22
5.10.1 Reason-Code AVP.............................................22
5.10.2 Reason-Info AVP.............................................23
5.11 Charging-Information AVP......................................23
5.11.1 Primary-Event-Charging-Function-Name AVP....................23
5.11.2 Secondary -Event-Charging-Function-Name AVP.................23
5.11.3 Primary-Charging-Collection-Function-Name AVP...............23
5.11.4 Secondary -Charging-Collection-Function-Name AVP............23
5.12 User-Authorization-Type AVP...................................23
5.13 User-Data-Request-Type AVP....................................24
5.14 User-Data-Already-Available AVP...............................24
6. Authentication Details..........................................25
7. IANA Considerations.............................................25
8 References.......................................................25
9 Authors' Addresses...............................................26
10. Full Copyright Statement.......................................27
1. Introduction
This document specifies a Diameter application that allows to perform
the authentication, authorization and collection of accounting
information for SIP-based IP multimedia services rendered to a client
node. We assume that a client node implements a SIP User Agent (UA)
that carries out SIP protocol actions with a SIP server, which in
turn relies on the AAA infrastructure for authenticating the client,
authorizing it for particular SIP services, and accounting for this
usage.
SIP servers can be proxy, redirect, registration, or user agent
servers. Additionally, SIP servers may be arranged in arbitrary ways
according to the inter-service provider relationships involved in
servicing a given client. For example, a mobile node may use a SIP
proxy in the visited network, but its SIP messages may be proxied
back to a SIP server in the home network that implements call control
features. Combined with the Inter-Domain capability of the base
protocol, this extension would allow such mobile terminals to receive
service from foreign service providers according to their location
and subscription profile. Any or all of the SIP servers may need to
independently authenticate the client, authorize service, and account
for usage.
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Authentication must take place at the time the user agent registers
with the SIP server (or chain of SIP proxies and servers) or at any
other moment agreed by the entities involved in the authentication
(e.g., at SIP session initiation). The particular algorithm used to
authenticate a SIP user agent client is a matter of policy agreement
between the user agent client, the SIP server, and the home AAA
server. This document supports the WWW-Authenticate methods Basic
and Digest, which are supported by SIP. In addition to
authenticating the user agent client, such a method could also be
used to generate or distribute keys for subsequent SIP-layer message
integrity and privacy. The specification of such an algorithm, and
its embedding in SIP, is outside the scope of this document.
Authorization for SIP services may take many forms. For example, a
proxy may need to know that the user agent client is authorized to
register, but from then on it may simply pass messages through to
other SIP servers. However, a SIP server that implements call
control features may need a richer and more complete description of
the services to which the user has subscribed.
Accounting for SIP services is on a per-call basis. An accounting
record contains a SIP Call-ID, any SDP that was exchanged to set up
the call, the duration of the call, and any resources that were
consumed on behalf of the call (such as number of bytes exchanged
between the parties). Note that accounting for resources may require
the SIP server to interact with other network entities, such as media
gateways, for the collection of this information. Such interaction
is outside the scope of this document. Some example scenarios,
inspired by the emerging wireless applications of SIP, are given in
Section 2. Sections 3, 4 and 5 address the Diameter Multimedia
Application's specific commands, result codes, and AVPs,
respectively. Section 7 gives IANA considerations.
1.1 Requirements language
In this document, the key words "MAY", "MUST, "MUST NOT", "optional",
"recommended", "SHOULD", and "SHOULD NOT", are to be interpreted as
described in [10].
2 Description of a SIP network architecture
Home Realm
+-------+
UAR/UAA +-->| AAA |<--+ PPR/PPA
LIR/LIA | |xyz.com| | MAR/MAA
| | | | SAR/SAA
| +-------+ | RTR/RTA
Local Realm v v
+-------+ +-------+ +-------+
| OSP |<----------->| HSP |<----->| SSP |
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|abc.com| SIP |xyz.com| SIP |xyz.com|
+-------+ +-------+ +-------+
^ ^
| SIP |
v |
+-------+ SIP |
| UAE |<----------------+
+-------+
bob@xyz.com
Figure 1: SIP network infrastructure
Figure 1 above illustrates the nodes involved in a SIP multimedia
network architecture, according to the requirements in [1]. The home
realm (xyz.com) is comprised of a Diameter AAA server, at least one
home entry SIP proxy (HSP) which is the gateway SIP proxy seen by the
rest of the world, and any number of serving SIP proxy (SSP) nodes.
These SSP nodes may be deployed piecemeal for various reasons such as
but not limited to load balancing, scalability, and offering
distinct, separate services.
The mobile node in this scenario (bob@xyz.com) may either connect
directly to its HSP, or via an outbound SIP server (OSP) in the local
realm. In larger networks, registrations MAY be routed to different
HSPs, potentially even for a subsequent SIP registration for the same
user, and thus HSPs are usually stateless.
The next few sections will describe in detail the different modes of
operation that are available to such an infrastructure. These
options may be either administratively configured to suit local
policies, or determined dynamically by the network. For the purposes
of authentication and authorization, the procedures involved when
using a OSP are a superset of the procedures involved in the absence
of a OSP, and therefore we will skip a needless explanation of the
latter scenario.
2.1 User authentication by SSP
An operator with a large base of installed SIP servers may wish to
minimize the impact of modifying SIP servers to interact with
Diameter AAA servers. This can be achieved by allowing SIP servers
to retain the functionality of authentication, rather than exporting
this capability to the AAA server. However, it should be noted that
this mode will not leverage the extensive array of authentication and
authorization services which will already be present regardless in
diameter servers. Below follows an example of a SIP user
registration using the SSP authentication mode.
+-------+ +-------+ +-------+
| HSP | | AAA | | SSP |
+---+---+ +---+---+ +---+---+
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| | |
1. SIP-REG | | |
---------->| 2. UAR | |
+------------------>| |
| 3. UAA | |
|<------------------+ |
| 4. SIP-REG | |
+-------------------------------------->|
| | 5. MAR |
| |<------------------+
| | 6. MAA |
| +------------------>|
| 7. 401 (Unauthorized) |
8. 401 |<--------------------------------------+
<-----------+ | |
9. SIP-REG | | |
---------->| 10. UAR | |
+------------------>| |
| 11. UAA | |
|<------------------+ |
| | 12. SIP-REG |
+-------------------------------------->|
| | 13. SAR |
| |<------------------+
| | 14. SAA |
| +------------------>|
| 15. 200 (OK) | |
16. 200 |<--------------------------------------+
<-----------+ | |
| | |
Figure 2: Authentication performed by the SSP
In this scenario, a user sends a SIP registration to the home domain.
The HSP will contact its local diameter server with a "User-
Authorization-Request" (UAR) to authorize if this user is allowed to
receive service, and if so, request the identity of a local SIP
server capable of handling this user. The diameter server will
respond with a "User-Authorization-Answer" (UAA), which will inform
about the result of the user authorization request in the Result-Code
AVP. The result values are defined in section 4 in addition to the
values defined in [2]. When the authorization successes, the UAA will
indicate either the identity of a local SIP server or a list of
capabilities from which the HSP will select the SSP.
If the result falls into the success category, then the HSP will
forward the registration request to the appropriate SSP. The SSP will
then request authentication parameters from the diameter server
through a "Multimedia-Auth-Request" (MAR). This request MAY also
serve to identify the SSP, so as to return subsequent registration
requests of the same user to the same SSP. The diameter server will
respond with a "Multimedia-Auth-Answer" (MAA), which will include all
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parameters necessary for the designated authentication algorithm
associated with the user. The SSP will then create the 401
(Unauthorized) message, including the authentication material needed
by the mobile user to prove his/her identity.
When the subsequent SIP registration is received from the user, the
HSP (assumed to be stateless) will once again contact the diameter
server with a UAR to determine to which SSP to forward the
registration. The HSP will then forward the SIP registration to the
SSP node. The SSP node performed the authentication in the previous
registration request by means of MAR/MAA, so at this point it is not
necessary to ask for it again, instead, it will contact the AAA
server by means of a Server-Assignment-Request (SAR) requesting it to
store the name of the server that is currently serving the user.
The AAA server will respond with a "Server-Assignment-Answer" (SAA).
If the Result-Code does not inform about an error, the User-Data AVP
shall contain the information that the SSP needs to give service to
the user.
The SSP will produce then a 200 (OK) message, and send it to the HSP.
The HSP will then forward the 200 (OK) message towards the mobile
user.
2.2 User authentication by AAA server
A different approach in deploying SIP networks is to allow the
Diameter server to perform the actual authentication. In addition to
leveraging the robust authentication services offered by the AAA
server, it will reduce the number of messages sent in the network.
+-------+ +-------+ +-------+
| HSP | | AAA | | SSP |
+---+---+ +---+---+ +---+---+
| | |
1. SIP-REG | | |
---------->| 2. UAR | |
+------------------>| |
| 3. UAA | |
|<------------------+ |
| | 4. SIP-REG |
+-------------------------------------->|
| | 5. MAR |
| |<------------------+
| | 6. MAA |
| +------------------>|
| 7. 401 (Unauthorized) |
8. 401 |<--------------------------------------+
<-----------+ | |
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9. SIP-REG | | |
---------->| 10. UAR | |
+------------------>| |
| 11. UAA | |
|<------------------+ |
| | 12. SIP-REG |
+-------------------------------------->|
| | 13. MAR |
| |<------------------+
| | 14. MAA |
| +------------------>|
| 15. 200 (OK) | |
16. 200 |<--------------------------------------+
<-----------+ | |
| | |
Figure 3: Authentication performed by the AAA server
In this scenario, the user will send a SIP register message to it's
home domain. When the HSP receives this request, it will contact its
local diameter server with a "User-Authorization-Request" (UAR) to
determine if this user is allowed to receive service and if so,
request the identity of a local SIP server capable of handling this
user, as described in the previous section. The diameter server will
respond with a "User-Authorization-Answer" (UAA), which will indicate
a list of capabilities from which the HSP will use to select the SSP.
Once it forwards the initial SIP registration to the appropriate SSP,
the SSP will then request user authentication from the Diameter
server through a "Multimedia-Auth-Request" (MAR). This request MAY
also serve to identify the SSP, so as to return subsequent
registration requests to the same SSP. The Diameter server will then
respond with a "Multimedia-Auth-Answer" (MAA) with Result-Code equal
to DIAMETER_MULTI_ROUND_AUTH and the challenge information, which the
SSP will use to map into the WWW-authentication header in the SIP 401
unauthorized and send back to the HSP.
When the subsequent SIP registration is received from the user, the
HSP will once again contact the diameter server with a UAR to
determine to which SSP to forward the registration. The HSP will then
forward the SIP registration to the SSP node, which will then extract
the relevant authentication parameters, and include these in a MAR
message to the AAA server. This request MAY also serve to identify
the SSP, so as to return subsequent registration requests to the same
SSP. At this point, the Diameter server will be able to authenticate
the user, and upon success, will return a MAA with Result-Code equal
to DIAMETER_SUCCESS and include user profile information, which the
SSP will use to give service to the user, the SSP will then produce a
200 (OK) message and send it to the HSP, which will then forward it
to the mobile user.
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2.3 Invitation
When a registered user wishes to invite another registered user, it
will send a SIP Invite request to the home domain (HSP) of the
invitee.
+-------+ +-------+ +-------+
| HSP | | AAA | | SSP |
+---+---+ +---+---+ +---+---+
| | |
1. SIP-INV | | |
---------->| 2. LIR | |
+------------------>| |
| 3. LIA | |
|<------------------+ |
| | 4. SIP-INV |
+-------------------------------------->|
| | |
Figure 5. A SIP Invite request
In this scenario, when a user, say Bob, contacts the HSP to invite
another user, say Mary, the MaryÆs HSP will issue a diameter
"Location-Info- Request" (LIR) message to the AAA server to request
the identity of the SSP currently assigned to Mary. The AAA server
will respond with a diameter "Location-Info-Answer" (LIA), indicating
the appropriate SSP, and the HSP will forward the SIP Invite message
directly to the named SSP.
2.4 User Profile Updating
Whenever a modification in the user profile has occurred, the AAA
server and SSP must synchronize their user profile data.
+-------+ +-------+
| AAA | | SSP |
+---+---+ +---+---+
| |
| 1. PPR |
+------------------>|
| |
| 2. PPA |
|<------------------+
| |
Figure 6. User profile update initiated by AAA server
The AAA server sends a Push-Profile-Request (PPR) to the serving SIP
server to which the user is registered. The PPR message contains a
SIP-User-Data AVP, a SIP-User-Name AVP, and zero or more SIP-Public-
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Identity AVPs. The presence of the SIP-User-Name AVP without any
SIP- Public-Identity AVPs serves to indicate that the entire user
profile associated with the SIP-User-Name AVP should be updated. A
PPR with a SIP-User-Name AVP and one or more SIP-Public-Identity AVPs
serves to indicate that the user profile data associated with each of
the SIP- Public-Identity AVPs should be updated.
2.5 User registration termination
Termination of an entire user registration can be achieved by one of
two mechanisms. In the event that NO_STATE_MAINTAINED (i.e NO
Diameter user session-id is maintained) has been indicated in a prior
Auth-Session-State AVP, termination is handled with a Session-
Termination-Request (if it is initiated by the SSP/HSP) or with a
Registration-Termination-Request (if it is initiated by the AAA).
On the other hand, if STATE_MAINTAINED has been indicated in a prior
Auth-Session-State AVP, the use of Session-Termination-Request (STR)
and Abort-Session-Request (ASR) messages as defined in the base
protocol are used to terminate an entire user registration.
Reasons for terminating a user registration could be due to the
expiration of the SIP registration timer in the SIP server, a user
initiated SIP de-registration, or a AAA-initiated de-registration as
a result of administrative reasons.
3 Command Codes
This section will define the specific message formats used by this
diameter application.
3.1 User-Authorization-Request (UAR) Command
The User-Authorization-Request (UAR), indicated by the Command-Code
field set to TBD and the 'R' bit set in the Command Flags field, is
sent by an HSP node, acting as a Diameter client, to a AAA server in
order to request authorization of a mobile user.
Message Format
< User-Authorization-Request > ::= Diameter Header: TBD: REQ, PXY >
< Session-ID >
< Auth-Application-Id >
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
[ Destination-Host ]
{ Destination-Realm }
{ SIP-User-Name }
{ SIP-Public-Identity }
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{ Visited-Network-Identifier }
[ User-Authorization-Type ]
* [ AVP ]
* [ Proxy-Info ]
* [ Route-Record ]
3.2 User-Authorization-Answer (UAA) Command
The User-Authorization-Answer (UAA), indicated by the Command-Code
field set to TBD and the 'R' bit cleared in the Command Flags field,
is sent by a AAA server in response to the User-Authorization-Request
command. The Result-Code AVP may contain one of the values defined in
section 4 in addition to the values defined in [2].
If the user has not previously been authorized, the UAA will make use
of the Server-Capabilities AVP to convey information needed by the
HSP to select an appropriate SSP.
If the user has already been authorized and a server has already been
assigned which is still valid for the user's service profile, the
SIP-Server-Name AVP MUST be present which contains the SIP URL of the
currently assigned server, so that the HSP can forward the
registration request to it.
If the user has already been authorized, and a server has already
been assigned which may not be valid for the user's service profile,
two pieces of information must be returned to allow the HSP to decide
what action to take. First, the Server-Name AVP MUST be present
which contains the SIP URL of the currently assigned server. Second,
the Server-Capabilities AVP MUST present which contains information
to allow the HSP to select an appropriate SIP server.
Message Format
< User-Authorization-Answer > ::= < Diameter Header: TBD: PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Session-State }
[ Result-Code ]
{ Origin-Host }
{ Origin-Realm }
[ SIP-Server]
[ Authorization-Lifetime ]
[ Auth-Grace-Period ]
*[ AVP ]
*[ Proxy-Info ]
*[ Route-Record ]
3.3 Server-Assignment-Request (SAR) Command
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The Server-Assignment-Request (SAR) command, indicated by the
Command-Code field set to TBD and the 'R' bit set in the Command
Flags field, is sent by a Diameter Multimedia client to a Diameter
Multimedia server in order to request it to store the name of the
server that is currently serving the user.
Message Format
<Server-Assignment-Request> ::= < Diameter Header: TBD, REQ, PXY>
< Session-Id >
{ Auth-Application-Id }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
[ Destination-Host ]
{ Destination-Realm }
[ SIP-User-Name ]
*[ SIP-Public-Identity ]
[ SIP-Server ]
{ SIP-Server-Assignment-Type }
{ User-Data-Request-Type }
{ User-Data-Already-Available }
*[ AVP ]
*[ Proxy-Info ]
*[ Route-Record ]
3.4 Server-Assignment-Answer (SAA) Command
The Server-Assignment-Answer (SAA) command, indicated by the Command-
Code field set to TBD and the 'R' bit cleared in the Command Flags
field, is sent by a server in response to the Server-Assignment-
Request command. The Result-Code AVP may contain one of the values
defined in section 4 in addition to the values defined in [2]. If
Result-Code does not inform about an error, the User-Data AVP shall
contain the information that the S-CSCF needs to give service to the
user.
Message Format
<Server-Assignment-Answer> ::= < Diameter Header: TBD: PXY >
< Session-Id >
{ Auth-Application-Id }
[ Result-Code ]
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
[ SIP-User-Data ]
[ Charging-Information ]
[ Auth-Grace-Period ]
[ Authorization-Lifetime ]
*[ AVP ]
*[ Proxy-Info ]
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*[ Route-Record ]
3.5 Location-Info-Request (LIR) Command
The Location-Info-Request (LIR), indicated by the Command-Code field
set to TBD and the 'R' bit set in the Command Flags field, is sent by
a HSP node, acting as a Diameter client, to a Diameter server in
order to request the identity of SIP server currently associated with
a particular user.
Message Format
< Location-Info-Request > ::= < Diameter Header: TBD, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
[ Destination-Host ]
{ Destination-Realm }
{ SIP-Public-Identity }
*[ AVP ]
*[ Proxy-Info ]
*[ Route-Record ]
3.6 Location-Info-Answer (LIA) Command
The Location-Info-Answer (LIA), indicated by the Command-Code field
set to TBD and the 'R' bit cleared in the Command Flags field, is
sent by a Diameter server in response to a Location-Info-Request. If
the user in the request is currently registered in the AAA server,
the answer will include the identity of the SIP server currently
associated with the user. The Result-Code AVP may contain one of the
values defined in section 4 in addition to the values defined in [2].
Message Format
< Location-Info-Answer > ::= < Diameter Header: TBD: PXY >
< Session-Id >
{ Auth-Application-Id }
[ Result-Code ]
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
[ SIP-Server ]
[ Auth-Grace-Period ]
[ Authorization-Lifetime ]
*[ AVP ]
*[ Proxy-Info ]
*[ Route-Record ]
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3.7 Multimedia-Auth-Request (MAR) Command
The Multimedia-Auth-Request (MAR), indicated by the Command-Code
field set to TBD and the 'R' bit set in the Command Flags field, is
sent by an SSP node, acting as a Diameter client, to a server in
order to request the authentication of a mobile user. The Diameter
client uses information found in the SIP Request to construct the
AVPs that are to be included as part of the MAR.
Message Format
< Multimedia-Auth-Request > ::= < Diameter Header: TBD, REQ, PXY >
< Session-ID >
{ Auth-Application-Id }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
[ Destination-Host ]
{ SIP-User-Name }
[ SIP-Public-Identity }]
[ SIP-Auth-Data-Item ]
[ SIP-Number-Auth-Items ]
[ SIP-Server ]
* [ AVP ]
* [ Proxy-Info ]
* [ Route-Record ]
3.8 Multimedia-Auth-Answer (MAA) Command
The Multimedia-Auth-Answer (MAA), indicated by the Command-Code field
set to TBD and the 'R' bit cleared in the Command Flags field, is
sent by the server in response to the Multimedia-Auth-Request
command. The Result-Code AVP may contain one of the values defined in
section 4 in addition to the values defined in [2].
Message Format
< Multimedia-Auth-Answer > ::= < Diameter Header: TBD, PXY >
< Session-Id >
{ Auth-Application-Id }
[ Result-Code ]
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
[ SIP-User-Name ]
[ SIP-Public-Identity ]
[ SIP-Number-Auth-Items ]
* [ SIP-Auth-Data-Item ]
[ SIP-User-Data ]
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[ Authorization-Lifetime ]
[ Auth-Grace-Period ]
* [ AVP ]
* [ Proxy-Info ]
* [ Route-Record ]
3.9 Registration-Termination-Request (RTR) Command
The Registration-Termination-Request (RTR) command, indicated by the
Command-Code field set to TBD and the 'R' bit set in the Command
Flags field, is sent by a Diameter Multimedia server to a Diameter
Multimedia client in order to request the de-registration of a user.
Message Format
<Registration-Termination-Request> ::= < Diameter Header: TBD, REQ,
PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Host }
{ Destination-Realm }
{ SIP-User-Name }
*[ SIP-Public-Identity ]
{ DeRegistration-Reason }
*[ AVP ]
*[ Proxy-Info ]
*[ Route-Record ]
3.10 Registration-Termination-Answer (RTA) Command
The Registration-Termination-Answer (RTA) command, indicated by the
Command-Code field set to TBD and the 'R' bit cleared in the Command
Flags field, is sent by a client in response to the Registration-
Termination-Request command. The Result-Code AVP may contain one of
the values defined in section 4 in addition to the values defined in
[2].
Message Format
<Registration-Termination-Answer> ::= < Diameter Header: TBD, PXY >
< Session-Id >
{ Auth-Application-Id }
[ Result-Code ]
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
[ Auth-Grace-Period ]
[ Authorization-Lifetime ]
*[ AVP ]
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*[ Proxy-Info ]
*[ Route-Record ]
3.11 Push-Profile-Request (PPR) Command
The Push-Profile-Request (PPR) command, indicated by the Command-Code
field set to TBD and the 'R' bit set in the Command Flags field, is
sent by a Diameter Multimedia server to a Diameter Multimedia client
in order to update the subscription data of a multimedia user in the
Diameter Multimedia client whenever a modification has occurred in
the subscription data that constitutes the data used by the client.
Message Format
< Push-Profile-Request > ::= < Diameter Header: TBD, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Host }
{ Destination-Realm }
{ SIP-User-Name }
{ SIP-User-Data }
*[ SIP-Public-Identity ]
[ Authorization-Lifetime ]
[ Auth-Grace-Period ]
*[ AVP ]
*[ Proxy-Info ]
*[ Route-Record ]
3.12 Push-Profile-Answer (PPA) Command
The Push-Profile-Answer (PPA) command, indicated by the Command-Code
field set to TBD and the 'R' bit cleared in the Command Flags field,
is sent by a client in response to the Push-Profile-Request command.
The Result-Code AVP may contain one of the values defined in section
4 in addition to the values defined in [2].
Message Format
< Push-Profile-Answer > ::=< Diameter Header: 10415: 305 >
< Session-Id >
{ Auth-Application-Id }
[Result-Code ]
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
*[ AVP ]
*[ Proxy-Info ]
*[ Route-Record ]
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4 Result Code AVP values
This section defines new Result codes in addition to the values
defined in [2].
4.1 Success
Errors that fall within the Success category are used to inform a
peer that a request has been successfully completed.
DIAMETER_FIRST_REGISTRATION 2xxx
The user was not previously registered, and has now been authorized
by the AAA server. Information necessary to select an appropriate
SSP SHOULD be included in the message.
DIAMETER_SUBSEQUENT_REGISTRATION 2xxx
The user has been previously registered, and has now been re-
authorized by the AAA server. The identity of the SSP to which the
user is currently registered SHOULD be included in the message.
DIAMETER_SEPARATE_REGISTRATION 2xxx
The user has been previously registered, but with a different public
identifier (and associated service profile). The identity of the SSP
to which the user is currently registered MUST be included in the
message, and in the event a new SSP must be assigned (based on the
new service profile), information necessary to select an appropriate
SSP MUST be included in the message as well.
DIAMETER_UNREGISTERED_SERVICE 2xxx
The user is not currently registered, but the requested service can
still be granted to the user.
4.2 Permanent failures
Errors that fall within the permanent failures category are used to
inform the peer that the request failed, and should not be attempted
again.
DIAMETER_ERROR_ROAMING_NOT_ALLOWED 5xxx
This error code is used to indicate that there is no multimedia
roaming agreement between the home and visited networks.
DIAMETER_ERROR_IDENTITY_ALREADY_REGISTERED 5xxx
The identity being registered has already a server assigned and the
registration status does not allow that it is overwritten.
DIAMETER_ERROR_IDENTITY_NOT_REGISTERED 5xxx
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This error code is used to inform that the received public identity
has not been registered before and the user to which this identity
belongs cannot be given service in this situation.
DIAMETER_ERROR_IDENTITIES_DONT_MATCH 5xxx
The value in one of the Public-Identity AVPs does not correspond to
the user specified in the SIP-User-Name AVP.
5 Diameter AVP values
The following sections define the AVPs used in this diameter
application.
5.1 SIP-Server AVP
The SIP-Server AVP (AVP code TBD) is of type Grouped. This AVP MAY be
used by the HSP to assist in the selection of a SSP.
SIP-Server ::= < AVP Header: TBD >
{ SIP-Server-Name }
* [ SIP-Server-Capability ]
* [ AVP ]
5.1.1 SIP-Server-Name AVP
The SIP-Server-Name AVP (AVP Code TBD) is of type UTF8String. This
AVP contains a SIP-URL (as defined in [5] and [6]) used to identify a
SIP server.
The HSP MAY include the SIP-Server-Name AVP to inform the Diameter
server which SSP to use for the SIP user or the SIP-Server-Name AVP
MAY be used by the Diameter server to inform the HSP that the SIP UA
client is assigned at the following SSP server.
5.1.2 SIP-Server-Capability AVP
The SIP-Capability AVP (AVP Code TBD) is of type Grouped. This AVP
is used to indicate support for particular SIP capability, and
contains the information to assist the HSP in the selection of an
SSP.
SIP-Capability ::= < AVP Header: TBD >
*[ Mandatory-Capability ]
*[ Optional-Capability ]
*[ AVP ]
5.1.2.1 Mandatory-Capability AVP
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The Mandatory-Capability AVP (AVP Code TBD) is of type Unsigned32.
The value included in this AVP can be used to represent a single
determined mandatory capability of an SSP. Each mandatory capability
available in an individual operatorÆs network shall be allocated a
unique value. The allocation of these values to individual
capabilities is an operator issue.
5.1.2.2 Optional -Capability AVP
The Optional-Capability AVP (AVP Code TBD) is of type Unsigned32. The
value included in this AVP can be used to represent a single
determined optional capability of an SSP. Each optional capability
available in an individual operatorÆs network shall be allocated a
unique value. The allocation of these values to individual
capabilities is an operator issue.
5.2 SIP-Public-Identity AVP
The SIP-Public-Identity AVP (AVP Code TBD) is of type OctetString,
encoded in the UTF-8 format. The syntax of this AVP corresponds
either to a SIP URL (with the format defined in [5] and [6]) or a TEL
URL (with the format defined in [7]).
This AVP contains the SIP public identity of a user in the IMS.
The Diameter client (HSP or SSP) uses information found in the header
of the SIP messages (e.g. To: field in REGISTER messages or From:
field in INVITE messages) to construct the SIP-Public-Identity AVP.
5.3 SIP-Visited-Network-Identifier AVP
The SIP-Visited-Network-Identifier AVP (AVP Code TBD) is of type
OctetString. This AVP contains an identifier that helps the home
network to identify the visited network (e.g. the visited network
domain name).
5.4 SIP-Server-Assignment-Type AVP
The Server-Assignment-Type AVP (AVP code TBD) is of type Enumerated,
and indicates the type of server update being performed in a Server-
Assignment-Request operation. The following values are defined:
NO_ASSIGNMENT (0)
This value is used to request from AAA the user profile assigned to
one or more public identities, without affecting the registration
state of those identities.
REGISTRATION (1)
The request is generated as a consequence of a first registration of
an identity.
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RE_REGISTRATION (2)
The request corresponds to the re-registration of an identity.
UNREGISTERED_USER (3)
The request is generated because the SSP received an INVITE for a
public identity that is not registered.
TIMEOUT_DEREGISTRATION (4)
The SIP registration timer of an identity has expired.
USER_DEREGISTRATION (5)
The SSP has received a user initiated de-registration request.
TIMEOUT_DEREGISTRATION_STORE_SERVER_NAME (6)
The SIP registration timer of an identity has expired. The S-CSCF
keeps the user data stored in the SSP and requests AAA to store the
SSP name.
USER_DEREGISTRATION_STORE_SERVER_NAME (7)
The SSP has received a user initiated de-registration request. The
SSP keeps the user data stored in the SSP and requests AAA to store
the SSP name.
ADMINISTRATIVE_DEREGISTRATION (8)
The SSP, due to administrative reasons, has performed the de-
registration of an identity.
AUTHENTICATION_FAILURE (9)
The authentication of a user has failed.
AUTHENTICATION_TIMEOUT (10)
The authentication timeout has expired.
5.5 SIP-Auth-Data-Item AVP
The SIP-Auth-Data-Item (AVP code TDB) is of type Grouped, and
contains the authentication and/or authorization information for the
Diameter client.
SIP-Auth-Data-Item :: = < AVP Header : TBD >
[ SIP-Item-Number ]
[ SIP-Authentication-Scheme ]
[ SIP-Authenticate ]
[ SIP-Authorization ]
[ SIP-Authentication-Info ]
[ SIP-Authentication-Context ]
* [ NAS-Session-Key ]
* [ AVP ]
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5.5.1 SIP-Item-Number AVP
The SIP-Item-Number (AVP code TDB) is of type Unsigned32, and is
included in a SIP-Auth-Data-Item grouped AVP in circumstances where
there are multiple occurrences of SIP-Auth-Data-Item AVPs, and the
order in which they should be processed is significant. In this
scenario, SIP-Auth-Data-Item AVPs with a low SIP-Item-Number value
(such as 1) should be processed before SIP-Auth-Data-Items AVPs with
a high SIP-Item-Number value (such as 13).
5.5.2 SIP-Authentication-Scheme AVP
The SIP-Authentication-Scheme AVP (AVP code TBD) is of type
UTF8String and indicates the authentication scheme used in the
authentication of SIP messages. Current values are "Basic" and
"Digest", defined in [8].
5.5.3 SIP-Authenticate AVP
The SIP-Authenticate AVP (AVP code TBD) is of type UTF8String and
contains the data portion of the WWW-Authenticate or Proxy-
Authenticate SIP headers if present in a SIP response.
5.5.4 SIP-Authorization AVP
The SIP-Authorization AVP (AVP code TBD) is of type UTF8String and
contains the data portion of the Authorization or Proxy-Authorization
SIP headers if present in a SIP request.
5.5.5 SIP-Authentication-Info AVP
The SIP-Authentication-Info AVP (AVP Code TBD) is of type OctetString
and contains additional authentication information sent by the AAA
server in case of Digest authentication. It follows the format
defined in RFC2617 for the Authentication-Info Header (sect 3.2.3).
The content of this AVP is to be mapped to the SIP Authentication-
Info header upon reception by the SIP server.
5.5.6 SIP-Authentication-Context AVP
The SIP-Authentication-Context AVP (AVP code TBD) is of type
OctectString, and contains authentication-related information
relevant for performing the authentication but that is not part of
the SIP authentication headers.
Some mechanisms (e.g. PGP, digest with quality of protection set to
auth-int [RFC 2617], digest with predictive nonces [7] or sip access
digest [8]) request that part or the whole SIP request is passed to
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the entity performing the authentication. In such cases the SIP-
Authentication-Context AVP would be carrying such information.
5.6 SIP-Number-Auth-Items AVP
The SIP-Number-Auth-Items AVP (AVP Code TBD) is of type Unsigned32
and indicates the number of authentication and/or authorization
vectors provided by the Diameter server.
When used in a request, it indicates the number of SIP-Auth-Data-
Items the SSP is requesting. This can be used, for instance, when the
SSP is requesting several pre-calculated authentication vectors. In
the answer message the SIP-Number-Auth-Items AVP indicates the actual
number of items provided by the Diameter server.
5.7 SIP-User-Data AVP
The SIP-User-Data AVP (AVP Code TBD) is of type OctetString, and MUST
NOT be interpreted by the Diameter protocol. This AVP contains the
user profile data required for a SIP server to give service to a
user.
5.8 NAS-Session-Key AVP
The NAS-Session-Key AVP is defined in [3].
5.9 NAS-Key-Binding AVP
The NAS-Key-Binding AVP is defined in [3].
5.10 SIP-Deregistration-Reason AVP
The SIP-Deregistration-Reason AVP (AVP Code TBD) is of type Grouped,
and indicates the reason for a deregistration operation.
Message format
SIP-Deregistration-Reason::= < AVP Header: TBD >
{ SIP-Reason-Code }
[ SIP-Reason-Info ]
* [ AVP ]
5.10.1 Reason-Code AVP
The Reason-Code AVP (AVP code TBD) is of type Enumerated, and defines
the reason for the network initiated de-registration. The following
values are defined:
PERMANENT_TERMINATION (0)
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NEW_SERVER_ASSIGNED (1)
SERVER_CHANGE (2)
REMOVE_SSP (3)
5.10.2 Reason-Info AVP
The Reason-Info AVP (AVP code TBD) is of type UTF8String, and
contains textual information to inform the user about the reason for
a de-registration.
5.11 Charging-Information AVP
The Charging-Information (AVP code TBD) is of type Grouped, and
contains the addresses of the charging functions.
AVP format
Charging-Information :: = < AVP Header : TBD >
[ Primary-Event-Charging-Function-Name ]
[ Secondary-Event-Charging-Function-Name ]
[ Primary-Charging-Collection-Function-Name ]
[ Secondary-Charging-Collection-Function-Name ]
*[ AVP]
5.11.1 Primary-Event-Charging-Function-Name AVP
The Primary-Event-Charging-Function-Name AVP (AVP Code TBD) is of
type DiameterURI. This AVP contains the address of the Primary Event
Charging Function.
5.11.2 Secondary -Event-Charging-Function-Name AVP
The Secondary-Event-Charging-Function-Name AVP (AVP Code TBD) is of
type DiameterURI. This AVP contains the address of the Secondary
Event Charging Function.
5.11.3 Primary-Charging-Collection-Function-Name AVP
The Primary-Charging-Collection-Function-Name AVP (AVP Code 22) is of
type DiameterURI. This AVP contains the address of the Primary
Charging Collection Function.
5.11.4 Secondary -Charging-Collection-Function-Name AVP
The Secondary-Charging-Collection-Function-Name AVP (AVP Code 23) is
of type DiameterURI. This AVP contains the address of the Secondary
Charging Collection Function.
5.12 User-Authorization-Type AVP
The User-Authorization-Type AVP (AVP code 24) is of type Enumerated,
and indicates the type of user authorization being performed in a
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User Authorization operation, i.e. UAR command. The following values
are defined:
REGISTRATION (0)
This value is used in case of the initial registration or re-
registration. HSP determines this from the Expires field in the SIP
REGISTER method if it is not equal to zero.
This is the default value.
DE_REGISTRATION (1)
This value is used in case of the de-registration. HSP determines
this from the Expires field in the SIP REGISTER method if it is equal
to zero.
REGISTRATION_AND_CAPABILITIES (3)
This value is used in case of initial registration or re-registration
and when the HSP explicitly requests SSP capability information from
the AAA.
5.13 User-Data-Request-Type AVP
The User-Data-Request-Type AVP (AVP code TBD) is of type Enumerated,
and indicates the type of user profile the SSP is requesting from the
HSS. The following values are defined:
COMPLETE_PROFILE (0)
This value is used to request from the AAA the complete user profile
corresponding to one or more public identities.
REGISTERED_PROFILE (1)
This value is used to request from the AAA the registered part of the
user profile corresponding to one or more public identities.
UNREGISTERED_PROFILE (2)
This value is used to request from the AAA the unregistered part of
the user profile corresponding to one or more public identities.
5.14 User-Data-Already-Available AVP
The User-Data-Already-Available AVP (AVP code TBD) is of type
Enumerated, and indicates to the HSS whether or not the SSP already
has the part of the user profile that it needs to serve the user. The
following values are defined:
USER_DATA_NOT_AVAILABLE (0)
The SSP does not have the data that it needs to serve the user.
USER_DATA_ALREADY_AVAILABLE (1)
The SSP already has the data that it needs to serve the user.
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6. Authentication Details
Authenticating a mobile user can occur through various mechanisms
(http basic or digest authentication have currently been prescribed),
with the actual authentication being performed in either the SIP
server or the AAA server. The choice of the server will determine
the AVPs to be utilized in the SIP-Auth-Data-Item grouped AVP, as
well as a few AVPs in the MAR/MAA.
In the event that the SIP server performs the authentication of a
mobile user, the MAR from the SIP server to the AAA server will
include the SIP-User-Name and SIP-Public-Identity AVPs as necessary,
as well a SIP-Number-Auth-Items AVP to indicate how many
authentication vectors (the actual contents of the vector are
dependent upon the authentication method) are being requested. In
the MAA, the AAA server SHOULD indicate how many SIP-Auth-Data-Item
AVPs are present with the Number-Auth-Items AVP, and may be different
from the amount requested in the MAR. If multiple SIP-Auth-Data-Item
AVPs are present, and their ordering is significant, the Item-Number
MUST be included in each grouping. The Authentication-Scheme and
SIP- Authenticate AVPs will contain data (typically a challenge of
some kind) to be used by the mobile user to authenticate itself. The
SIP- Authorization AVP will contain the response which is expected
from the user. In order to support some auth methods which combine
key distribution with authentication, NAS-Session-Key AVPs may be
included in the event they were requested by including "SIP crypto
node" as one of the Server-Type AVPs in the MAR.
In the event that the AAA server performs the authentication of a
mobile user, the MAR from the SIP server will include a single SIP-
Auth-Data-Item AVP. The SIP-Authentication-Scheme and SIP
Authorization AVPs will contain the relevant parameters from the SIP
message if present, and if necessary, the SIP-Authentication-Context
AVP will contain any additional information needed to perform the
authentication. If the authentication is successful, the MAA will
contain a result code indicating success, and if necessary, the SIP-
Auth-Data-Item AVP may be included to carry session keys back to the
SIP server. If the authentication is unsuccessful due to missing
credentials, the MAA will include an SIP-Auth-Data-Item with the SIP-
Authentication-Scheme and SIP-Authenticate AVPs containing data
(typically a challenge of some kind) to be used by the mobile user to
authenticate itself.
7. IANA Considerations
Command Code values are assigned according to the reference [9].
8 References
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[1] Loughney, Camarillo, Authentication, Authorization and
Accounting Requirements ", draft-ietf-sipping-aaa- req-00.txt, IETF
work in progress, August 2002
[2] Calhoun, Akhtar, Arkko, Guttman, Rubens, Zorn, "Diameter Base
Pro¡tocol", draft-ietf-aaa-diameter-15.txt, IETF work in progress,
October 2002
[3] Calhoun, Bulley, Rubens, Haag, Zorn, "Diameter NASREQ
Application", daft-ietf-aaa-diameter-nasreq-09.txt, IETF work in
progress, March 2002
[4] Calhoun, Johansson, Perkins, "Diameter Mobile IPv4 Application,"
draft-ietf-diameter-mobileip-13.txt, IETF work in progress, October
2002
[5] M. Handley, H. Schulzrinne, E. Schooler, J. Rosenberg, "SIP:
Ses¡sion Initiation Protocol". RFC 3261, June 2002
[6] IETF RFC 2396: "Uniform Resource Identifiers (URI): generic
syntax"
[7] IETF RFC 2806: "URLs for Telephone Calls"
[8] IETF RFC 2617: "HTTP Authentication: Basic and Digest Access
Authentication"
[9] J. Loughney, "Provisional Diameter Command Codes for 3GPP",
draft-loughney-aaa-cc-3gpp-00.txt, IETF work in progress, October
2002
[10] IETF RFC 2119: "Key words for use in RFCs to Indicate
Requirement Levels"
9 Authors' Addresses
Carolina Canales Phone: +34 913392680
Ericsson Spain Fax: +34 913392538
Via de los Poblados, 13
28033 Madrid
Spain
E-mail: carolina.canales-valenzuela@ece.ericsson.se
Miguel-Angel Pallares Phone: +34 913394222
Ericsson Spain Fax: +34 913392538
Via de los Poblados, 13
28033 Madrid
Spain
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E-mail: miguel-angel.pallares-lopez@ece.ericsson.se
Maria-Carmen Belinchon Phone: +34 913393535
Ericsson Spain Fax: +34 913392906
Via de los Poblados, 13
28033 Madrid
Spain
E-mail: maria.c.belinchon@ericsson.com
Peter J. McCann Phone: +1 630 713 9359
Lucent Technologies Fax: +1 630 713 4982
Rm 2Z-305
263 Shuman Blvd
Naperville, IL 60566-7050
USA
E-Mail: mccap@lucent.com
Jaakko Rajaniemi Phone: +358 50 3391387
Nokia Networks Fax: +358 9 51130163
P.O. Box 301
00045 Nokia Group
Finland
E-mail: jaakko.rajaniemi@nokia.com
10. Full Copyright Statement
Copyright (C) The Internet Society (2001). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this docu¡
ment itself may not be modified in any way, such as by removing the
copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of develop¡
ing Internet standards in which case the procedures for copyrights
defined in the Internet Standards process must be followed, or as
required to translate it into languages other than English. The lim¡
ited permissions granted above are perpetual and will not be revoked
by the Internet Society or its successors or assigns. This document
and the information contained herein is provided on an "AS IS" basis
and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DIS¡
CLAIMS 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.
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