AAA Working Group M. Garcia-Martin, Ed.
Internet-Draft Nokia
Expires: June 16, 2005 M. Belinchon
M. Pallares-Lopez
C. Canales
Ericsson
K. Tammi
Nokia
December 16, 2004
Diameter Session Initiation Protocol (SIP) Application
draft-ietf-aaa-diameter-sip-app-05
Status of this Memo
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RFC 3668.
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Copyright Notice
Copyright (C) The Internet Society (2004).
Abstract
This document specifies the Diameter Session Initiation Protocol
(SIP) Application. This is a Diameter application that allows a
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Diameter client to request authentication and authorization
information. This application is designed to be used in conjunction
with the Session Initiation Protocol (SIP), and provides a Diameter
client in a SIP server with the ability to request a Diameter server
the authentication of users and authorization of SIP resources usage.
Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Applicability . . . . . . . . . . . . . . . . . . . . . . . 6
5. Overview of Operation . . . . . . . . . . . . . . . . . . . 6
5.1 General Architecture . . . . . . . . . . . . . . . . . . . 7
5.2 Diameter Server Authenticates the User . . . . . . . . . . 8
5.3 Delegating Final Authentication Check to the SIP Server . 11
5.4 SIP Server Authenticates a Request . . . . . . . . . . . . 14
5.5 Locating the recipient of the SIP request . . . . . . . . 15
5.6 Update of the User Profile . . . . . . . . . . . . . . . . 16
5.7 SIP Soft State Termination . . . . . . . . . . . . . . . . 17
5.8 Diameter Server Discovery . . . . . . . . . . . . . . . . 18
6. Advertising Application Support . . . . . . . . . . . . . . 20
7. Diameter SIP Application Command Codes . . . . . . . . . . . 21
7.1 User-Authorization-Request (UAR) Command . . . . . . . . . 21
7.2 User-Authorization-Answer (UAA) Command . . . . . . . . . 22
7.3 Server-Assignment-Request (SAR) Command . . . . . . . . . 26
7.4 Server-Assignment-Answer (SAA) Command . . . . . . . . . . 28
7.5 Location-Info-Request (LIR) Command . . . . . . . . . . . 32
7.6 Location-Info-Answer (LIA) Command . . . . . . . . . . . . 32
7.7 Multimedia-Auth-Request (MAR) Command . . . . . . . . . . 34
7.8 Multimedia-Auth-Answer (MAA) Command . . . . . . . . . . . 35
7.9 Registration-Termination-Request (RTR) Command . . . . . . 38
7.10 Registration-Termination-Answer (RTA) Command . . . . . 39
7.11 Push-Profile-Request (PPR) Command . . . . . . . . . . . 41
7.12 Push-Profile-Answer (PPA) Command . . . . . . . . . . . 42
8. Diameter SIP Application AVPs . . . . . . . . . . . . . . . 43
8.1 SIP-Accounting-Information AVP . . . . . . . . . . . . . . 45
8.1.1 SIP-Accounting-Server-URI AVP . . . . . . . . . . . . 46
8.1.2 SIP-Credit-Control-Server-URI AVP . . . . . . . . . . 46
8.2 SIP-Server-URI AVP . . . . . . . . . . . . . . . . . . . . 46
8.3 SIP-Server-Capabilities AVP . . . . . . . . . . . . . . . 46
8.3.1 SIP-Mandatory-Capability AVP . . . . . . . . . . . . . 46
8.3.2 SIP-Optional-Capability AVP . . . . . . . . . . . . . 47
8.4 SIP-Server-Assignment-Type AVP . . . . . . . . . . . . . . 47
8.5 SIP-Auth-Data-Item AVP . . . . . . . . . . . . . . . . . . 48
8.5.1 SIP-Authentication-Scheme AVP . . . . . . . . . . . . 48
8.5.2 SIP-Item-Number AVP . . . . . . . . . . . . . . . . . 49
8.5.3 SIP-Authenticate AVP . . . . . . . . . . . . . . . . . 49
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8.5.4 SIP-Authorization AVP . . . . . . . . . . . . . . . . 50
8.5.5 SIP-Authentication-Info AVP . . . . . . . . . . . . . 50
8.5.6 Digest AVPs . . . . . . . . . . . . . . . . . . . . . 51
8.6 SIP-Number-Auth-Items AVP . . . . . . . . . . . . . . . . 53
8.7 SIP-Deregistration-Reason AVP . . . . . . . . . . . . . . 53
8.7.1 SIP-Reason-Code AVP . . . . . . . . . . . . . . . . . 53
8.7.2 SIP-Reason-Info AVP . . . . . . . . . . . . . . . . . 53
8.8 SIP-AOR AVP . . . . . . . . . . . . . . . . . . . . . . . 54
8.9 SIP-Visited-Network-Id AVP . . . . . . . . . . . . . . . . 54
8.10 SIP-User-Authorization-Type AVP . . . . . . . . . . . . 54
8.11 SIP-Supported-User-Data-Type AVP . . . . . . . . . . . . 55
8.12 SIP-User-Data AVP . . . . . . . . . . . . . . . . . . . 55
8.12.1 SIP-User-Data-Type AVP . . . . . . . . . . . . . . . 56
8.12.2 SIP-User-Data-Contents AVP . . . . . . . . . . . . . 56
8.13 SIP-User-Data-Already-Available AVP . . . . . . . . . . 56
8.14 SIP-Method AVP . . . . . . . . . . . . . . . . . . . . . 56
9. New Values for Existing AVPs . . . . . . . . . . . . . . . . 57
9.1 Extension to the Result-Code AVP Values . . . . . . . . . 57
9.1.1 Success Result-Code AVP Values . . . . . . . . . . . . 57
9.1.2 Transient Failures Result-Code AVP Values . . . . . . 58
9.1.3 Permanent failures Result-Code AVP Values . . . . . . 58
10. Authentication Details . . . . . . . . . . . . . . . . . . . 59
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . 60
11.1 Application Identifier . . . . . . . . . . . . . . . . . 60
11.2 Command Codes . . . . . . . . . . . . . . . . . . . . . 61
11.3 AVP Codes . . . . . . . . . . . . . . . . . . . . . . . 61
11.4 Additional Values for the Result-Code AVP Value . . . . 61
12. Security Considerations . . . . . . . . . . . . . . . . . . 61
13. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 62
14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 62
15. Changes With Respect Previous Versions . . . . . . . . . . . 62
15.1 Changes in draft-ietf-aaa-diameter-sip-app-05.txt
from -04.txt . . . . . . . . . . . . . . . . . . . . . . 62
15.2 Changes in draft-ietf-aaa-diameter-sip-app-04.txt
from -03.txt . . . . . . . . . . . . . . . . . . . . . . 63
15.3 Changes in draft-ietf-aaa-diameter-sip-app-03.txt
from -02.txt . . . . . . . . . . . . . . . . . . . . . . 64
15.4 Changes in draft-ietf-aaa-diameter-sip-app-02.txt
from -01.txt . . . . . . . . . . . . . . . . . . . . . . 65
15.5 Changes in draft-ietf-aaa-diameter-sip-app-01.txt
from -00.txt . . . . . . . . . . . . . . . . . . . . . . 65
15.6 Changes in draft-ietf-aaa-diameter-sip-app-00.txt
from draft-belinchon-aaa-diameter-mm-app-01.txt . . . . 66
16. References . . . . . . . . . . . . . . . . . . . . . . . . . 66
16.1 Normative References . . . . . . . . . . . . . . . . . . . 66
16.2 Informational References . . . . . . . . . . . . . . . . . 67
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 68
Intellectual Property and Copyright Statements . . . . . . . 70
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1. Terminology
In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT
RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as
described in BCP 14, RFC 2119 [RFC2119] and indicate requirement
levels for compliant implementations.
2. Definitions
For the purpose of this document, the following terms and definitions
apply.
o 'Node: ' an addressable device attached to a computer network that
implements SIP functionality, Diameter functionality or a
combination of both.
For the purpose of this document, the following terms and definitions
given in RFC 3261 [RFC3261] Section 6, apply:
o 'Address-of-Record (AOR)'
o 'Outbound proxy'
o 'Proxy'
o 'Server (SIP server)'
o 'User Agent (UA)'
o 'User Agent Client (UAC)'
For the purpose of this document, the following terms and definitions
given in RFC 3588 [RFC3588] Section 1.3, apply:
o 'Authorization'
o 'Authentication'
o 'AVP'
o 'Diameter Client'
o 'Diameter Server'
o 'Home Realm'
o 'Redirect Agent'
o 'User'
3. Introduction
This document specifies the Diameter Session Initiation Protocol
(SIP) Application. This is a Diameter application that allows a
Diameter client to request authentication and authorization
information to a Diameter server for Session Initiation Protocol
(SIP) [RFC3261] based IP multimedia services. We assume that the SIP
server and the Diameter client are located in the same node, so that
the SIP server is able to receive and process SIP requests and
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responses which in turn relies on the AAA infrastructure for
authenticating the SIP request and authorizing the usage of
particular SIP services.
This document provides Diameter procedures to implement certain
required functionality when SIP is the protocol chosen to initiate
and tear-down multimedia sessions or when SIP is used for other
non-session related applications. However, this document does not
mandate any particular mapping of SIP procedures to Diameter SIP
application procedures, nor does it mandate any particular sequence
of events between SIP and Diameter. This document provides useful
examples to show the interaction between SIP and the Diameter SIP
application in order to achieve the desired functionality.
This application does not require or is not related to other
authentication services provided by the Mobile IP Diameter
[I-D.ietf-aaa-diameter-mobileip] or the Network Access Server
Diameter [I-D.ietf-aaa-diameter-nasreq] applications.
This Diameter SIP application is loosely related to the Diameter
Credit Control Application [I-D.ietf-aaa-diameter-cc]. Although both
applications are independent, the Diameter SIP application is able to
supply the addresses of credit control servers that will be
implementing the Diameter Credit Control Application
[I-D.ietf-aaa-diameter-cc].
The Applicability section (Section 4) discusses assumptions and
configurations assumed by this document.
The Overview of Operation section (Section 5) provides the reader
with informative descriptions of the Diameter SIP application
commands and responses and some guidance to their linkage with SIP
procedures.
Advertising of this application is specified in Section 6.
The Diameter SIP application Command Codes chapter (Section 7)
provides a normative description of all the new Diameter commands
defined by this specification.
This application extends the Result-Code Attribute-Value-Pair (AVP)
with some new values. Further information is described in the New
values for existing AVPs chapter (Section 9).
This application defines some new AVPs. All these AVPs are described
in the Diameter SIP application AVPs chapter (Section 8).
Some extra information about authentication is provided in the
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Authentication details chapter (Section 10).
4. Applicability
This document assumes a general architecture where a Home Realm is
composed of one or more nodes implementing Diameter or SIP functions.
Users are issuing SIP request to access SIP resources. For each
particular user, the Home Realm needs to authenticate and authorize
the usage of those resources and/or route to the appropriate node.
We assume that the database containing the user related data is
located outside the SIP node that requires authorization. Data
belonging to different users may be stored in different nodes in the
Home Realm, but we assume that all the data related to a particular
user is stored in a single node.
Central to the architecture is the fact that the user data is
stored in a single point in the network. This restriction does
not mandate a particular implementation, e.g., it is possible to
implement clusters of databases operating in mirror mode to
provide redundancy. The property required by this specification
is that the user data the Diameter Server has access to is stored
safely in what, from the external point of view, is seen as a
single user database.
This document allows several configurations of the Home Realm. In
one configuration, a SIP server is allocated to a user for the
purpose of triggering and executing services. The allocation of the
SIP server may be done dynamically, e.g., at the time the user
registers in the network. This configuration requires a SIP server,
typically located at the edge of the network, that is able to
allocate another SIP server for the user and also supports routing of
SIP requests and responses towards that allocated SIP server. Both
SIP server nodes implement a Diameter Client.
In another configuration, the address of a SIP outbound proxy is
configured (by means outside the scope of this specification) into
the SIP endpoint. The outbound Diameter Client in the SIP outbound
proxy node authenticates the user, requests authorization for SIP
requests and performs accounting activities.
5. Overview of Operation
This section provides an informative description of how the Diameter
SIP application can be used together with SIP. This section is not
intended to mandate any specific usage of the Diameter SIP
application nor does it mandate a specific mapping between SIP and
Diameter messages. This section is a collection of examples that
show how the required AAA functionality can be achieved in
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conjunction with SIP.
5.1 General Architecture
The Diameter SIP application can be used in a SIP environment where
an interface to a AAA infrastructure is required to authenticate and
authorize the usage of SIP resources. This application provides a
limited support for accounting services, limited to the Diameter
server being able to provide the addresses of accounting severs to
the Diameter client. Figure 1 below shows a general overview of the
integration of the SIP architecture with the AAA architecture.
According to Figure 1, there is one or more SIP User Agents (UA) that
initiate or terminate SIP traffic through one or more SIP servers.
Both SIP servers implement a Diameter client that supports the
Diameter application described in this specification.
+--------+
UAR/UAA +--->|Diameter|<----+ PPR/PPA
LIR/LIA | | server | | MAR/MAA
| +--------+ | SAR/SAA
| | RTR/RTA
| |
v v
+------+ SIP +--------+ SIP +--------+ SIP +------+
| SIP |<--------->| SIP |<-------->| SIP |<--------->| SIP |
| UA | |server 1| |server 2| | UA |
+------+ +--------+ +--------+ +------+
^ ^
UAR/UAA | |
LIR/LIA | | MAR/MAA
| +--------+ | SAR/SAA
+--->|Diameter|<----+
| SL |
+--------+
Figure 1: Architecture of the Diameter application for SIP
In Figure 1, it can be seen that SIP server 1 sends different
Diameter commands and receives different responses to those sent and
received by SIP server 2. This is because SIP server 1 in Figure 1
is located at the edge of a network, and its main task is to locate
SIP server 2. SIP server 2 is requesting and receiving
authentication and authorization data from the Diameter server and is
not located at the edge of the network.
The Diameter Subscriber Locator (SL) serves for the purposes of
locating the Diameter server that contains the user related data.
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Its functionality is based on the Diameter redirect mechanism, and is
further described in Section 5.8.
It should be noted that this document does not mandate any particular
SIP/AAA architecture. However, the Diameter SIP application provides
the functionality needed to accommodate all the different
architectures where SIP and Diameter are used.
The following subsections provide an informative overview of the
Diameter SIP application, its commands, and a possible interaction
with SIP signaling.
5.2 Diameter Server Authenticates the User
This is the generic mechanism to authenticate users. In this
approach we show an example of an administrative network where the
Diameter server is authenticating SIP user requests. This could be
the case of a medium size network where the Diameter server is
keeping user records and authenticating SIP requests to perform a
certain transaction. We have chosen to show a SIP REGISTER request
in the example, but the SIP server could request authentication of
any other SIP request.
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+--------+ +--------+ +--------+
| SIP | |Diameter| | SIP |
|server 1| | server | |server 2|
+--------+ +--------+ +--------+
| | |
1. SIP REGISTER | | |
-------------------->| 2. UAR | |
|------------------>| |
| 3. UAA | |
|<------------------| |
| 4. SIP REGISTER |
|-------------------------------------->|
| | 5. MAR |
| |<------------------|
| | 6. MAA |
| |------------------>|
| 7. SIP 401 (Unauthorized) |
8. SIP 401 (Unauth.) |<--------------------------------------|
<--------------------| | |
9. SIP REGISTER | | |
-------------------->| 10. UAR | |
|------------------>| |
| 11. UAA | |
|<------------------| |
| 12. SIP REGISTER |
|-------------------------------------->|
| | 13. MAR |
| |<------------------|
| | 14. MAA |
| |------------------>|
| 15. SIP 200 (OK) |
16. SIP 200 (OK) |<--------------------------------------|
<--------------------| | |
| | 17. SAR |
| |<------------------|
| | 18. SAA |
| |------------------>|
| | |
Figure 2: Authentication performed in the Diameter server
According to Figure 2 a SIP User Agent Client (UAC) sends a SIP
REGISTER request (step 1) to SIP server 1, which will receive the SIP
request. We assume that this SIP server may be located, e.g., at the
edge of the administrative home domain. The Diameter client in SIP
server 1 will contact its Diameter server by sending a Diameter
User-Authorization-Request (UAR) message (step 2) to determine if
this user is allowed to receive service, and if so, request the
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address of a local SIP server capable of handling this user. The
Diameter server will answer with a Diameter User-Authorization-Answer
(UAA) message (step 3), which will indicate either a list of
capabilities that SIP server 1 may use to select an appropriate SIP
server (SIP server 2) and/or a SIP or SIPS URI pointing to SIP server
2.
SIP server 1 will forward the SIP REGISTER request (step 4) to an
appropriate SIP server (SIP server 2). The Diameter client in SIP
server 2 will then request user authentication from the Diameter
server by sending a Diameter Multimedia-Auth-Request (MAR) message
(step 5). This request will also serve to make the Diameter server
aware of the SIP or SIPS URI of SIP server 2, so as to return
subsequent requests for the same user to the same SIP server 2. The
Diameter server will respond with a Diameter Multimedia-Auth-Answer
(MAA) message (step 6) with Result-Code AVP set to the value
DIAMETER_MULTI_ROUND_AUTH. The Diameter server will also include a
challenge, which SIP server 2 will use to map into the
WWW-authentication header in the SIP 401 (Unauthorized) response
(step 7), which is sent back to SIP server 1 and then to the SIP UAC
(step 8).
SIP server 1 will receive a next SIP REGISTER request containing the
user credentials (step 9). Note that SIP server 1 does not need to
keep a state, and even more, there is no guarantee that the SIP
request will arrive at the same SIP server 1, there could be a farm
of SIP servers 1 operating in redundant configuration. The Diameter
client in SIP server 1 will contact a Diameter server by sending a
Diameter UAR message (step 10) to determine the SIP server allocated
to the user. The Diameter server will send the SIP or SIPS URI of
SIP server 2 in a Diameter UAA message (step 11).
SIP server 1 will then forward the SIP REGISTER request to SIP server
2 (step 12). SIP server 2 will extract the credentials from the SIP
REGISTER request. The Diameter client in SIP server 2 will send
those credentials in a Diameter MAR message (step 13) to the Diameter
server. At this point, the Diameter server will be able to
authenticate the user, and upon success, will return a Diameter MAA
message (step 14) with the AVP Result-Code set to the value
DIAMETER_SUCCESS.
SIP server 2 will then generate a SIP 200 (OK) response (step 15)
which is forwarded to SIP server 1 and eventually to the SIP UAC
(step 16).
If the Diameter client in SIP server 2 is interested in downloading
the user profile information or requires to store the address of the
SIP server in the Diameter server, then the Diameter client will send
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a Diameter SAR message (step 17) to the Diameter server. The
Diameter server will reply with a Diameter SAA message (step 18) that
contains the requested user profile information and the
acknowledgement of the SIP server address storage. These actions are
needed when the SIP server needs to retrieve a user profile used to
provide services to the served user or when the SIP server will keep
a state for the user, so the Diameter server needs to store its
address.
5.3 Delegating Final Authentication Check to the SIP Server
An operator with a large base of installed SIP servers may wish to
minimize the number of round trips between the Diameter client and
the Diameter server. We provide support for a mechanism that allows
the Diameter server to delegate the final authentication check to the
SIP server, saving a round trip. However, it must also noted that
this scenario is only applicable when the authentication of the user
does not use client nonces, since the mechanism is based on the
computation of an expected response in the Diameter server, which
makes it available to the SIP server.
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+--------+ +--------+ +--------+
| SIP | |Diameter| | SIP |
|server 1| | server | |server 2|
+--------+ +--------+ +--------+
| | |
1. SIP REGISTER | | |
-------------------->| 2. UAR | |
|------------------>| |
| 3. UAA | |
|<------------------| |
| 4. SIP REGISTER |
|-------------------------------------->|
| | 5. MAR |
| |<------------------|
| | 6. MAA |
| |------------------>|
| 7. SIP 401 (Unauthorized) |
8. SIP 401 (Unauth.) |<--------------------------------------|
<--------------------| | |
9. SIP REGISTER | | |
-------------------->| 10. UAR | |
|------------------>| |
| 11. UAA | |
|<------------------| |
| 12. SIP REGISTER |
|-------------------------------------->|
| | 13. SAR |
| |<------------------|
| | 14. SAA |
| |------------------>|
| 15. SIP 200 (OK) |
16. SIP 200 (OK) |<--------------------------------------|
<--------------------| | |
| | |
Figure 3: Delegation of authentication to the SIP server
Figure 3 shows an example where a SIP server is dynamically allocated
to serve a SIP User Agent with the support of the Diameter server.
This may be the case of certain architectures, such as that of the
3rd Generation Partnership Project (3GPP) IP Core Network Multimedia
Subsystem (IMS).
A first SIP server receives a SIP REGISTER request (step 1) whose
target is the home network domain. We assume that this SIP server
may be located, e.g., at the edge of the administrative home domain.
The Diameter client in this SIP server requests authorization from
the Diameter server to proceed with the registration, by sending a
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Diameter User-Authorization-Request (UAR) message (step 2). The
message includes, among other Attribute-Value-Pairs (AVP), the SIP
address-of-record that is included in the SIP REGISTER request. The
Diameter server will verify the SIP address-of-record and, if it is a
valid defined user in the home network, will authorize the
registration to proceed. The Diameter server will respond with a
Diameter User-Authorization-Answer (UAA) message (step 3), which will
inform the Diameter client/SIP server about the result of the user
authorization. In case of a successful authorization, the Diameter
UAA message will indicate either the address of a local SIP server
(SIP server 2 in Figure 3) and/or a list of capabilities that SIP
server 1 may use to select an appropriate SIP server 2.
When the authorization is successful, SIP server 1 will forward the
SIP REGISTER request (step 4) to the appropriate SIP server (SIP
server 2). The Diameter client in SIP server 2 will then request
authentication parameters by sending a Diameter
Multimedia-Auth-Request (MAR) message (step 5) to the Diameter
server. This request will also serve to make the Diameter server
aware of the SIP or SIPS URI of SIP server 2, so as to return
subsequent requests of the same user to the same SIP server 2. The
Diameter server will respond with a Diameter Multimedia-Auth-Answer
(MAA) message (step 6), which will include all parameters necessary
for the designated authentication algorithm associated with the user.
Among others, the MAA message will include a Digest-HA1 AVP that
contains H(A1) (as defined in RFC 2617 [RFC2617]), and allows the
Diameter client to calculate the expected response. Then the
Diameter client can use this expected response compare it with the
response to the challenge sent from the SIP UA. If the Digest-HA1
AVP is not present in MAA, it indicates that authentication and
authorization will take place in the Diameter server, as per the
scenario described in Section 5.2.
SIP server 2 will then create a SIP 401 (Unauthorized) SIP response
(step 7) based on the challenge included in the MAA message,
including the authentication material needed by the SIP User Agent
Client (UAC) to include the appropriate credentials. SIP server 1
forwards the SIP response to the SIP UAC (step 8).
When SIP server 1 receives a next SIP REGISTER request containing the
user credentials (step 9), as SIP server 1 does not need to keep a
state (even there is no guarantee that the SIP request arrives to the
same SIP server 1), the Diameter client in SIP server 1 will contact
again the Diameter server by sending a Diameter UAR message (step 10)
to determine the SIP server allocated to the user. The Diameter
server will send the SIP or SIPS URI of SIP server 2 in a Diameter
UAA message (step 11).
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SIP server 1 will then forward the SIP REGISTER request to SIP server
2 (step 12). If the credentials include a client nonce, then SIP
server 2 falls back to the authentication in the Diameter server (see
Section 5.2). Otherwise, SIP server 2 will validate the credentials
by comparing the response supplied by the SIP UA with the expected
response supplied by the Diameter server.
If the credentials are valid, SIP server 2 will send a Diameter
Server-Assignment-Request (SAR) message (step 13) requesting the
Diameter server to confirm the completion of the authentication
procedure and to confirm the SIP or SIPS URI of the SIP server that
is currently serving the user. The Diameter SAR message also serves
the purpose to request the Diameter server to send the user profile
to the SIP server. The Diameter server will respond with a Diameter
Server-Assignment-Answer (SAA) message (step 14). If the Result-Code
AVP value does not inform about an error, the SAA message can contain
zero or more SIP-User-Data AVPs will contain the information that SIP
server 2 needs in order to provide a service to the user.
SIP server 2 generates a SIP 200 (OK) response (step 15) that will be
forwarded to SIP server 1 and eventually to the SIP UAC (step 16).
5.4 SIP Server Authenticates a Request
Figure 4 depicts a typical scenario where a stateless SIP proxy
requests authentication information and authorization to a Diameter
server, for the purpose of providing SIP routing services to a SIP
User Agent. The SIP proxy server may be configured as an outbound
SIP proxy, so that all the requests initiated by the SIP UA traverse
the SIP proxy.
According to Figure 4, a SIP User Agent sends a SIP request to its
outbound SIP proxy server. In this case, the message is a SIP INVITE
request (see step 1), but it could be any other SIP request. We
assume that this SIP request does not contain any credentials at this
time. The outbound SIP proxy server needs to authenticate and
authorize the proxy services offered to the user. The Diameter
client in the SIP server sends a Multimedia-Auth-Request (MAR)
message (step 2). The Diameter server sends a Multimedia-Auth-Answer
(MAA) message (step 3) that includes all the data necessary for the
SIP server to challenge the user, typically with HTTP Digest
Authentication indicated in the MAA message. This data will serve
the SIP server to create a SIP 407 (Proxy Authentication Required)
response (step 4) that contains a challenge. The SIP UA will create
a new INVITE request (step 5) that contains the credentials. The
Diameter client in the SIP server will send the credentials to the
Diameter server in a new Diameter MAR message (step 6). The Diameter
server will validate the credentials and authorize the SIP
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transaction in a Diameter MAA message (step 7). The SIP server
forwards the SIP INVITE request to its destination (step 8) as per
regular SIP procedures. Eventually, the session setup will be
confirmed with a SIP 200 (OK) response (step 9) that is forwarded to
the SIP UA (step 10). The session setup is complete.
+--------+ +--------+
|Diameter| | SIP |
| server | | server |
+--------+ +--------+
| |
| |
1. SIP INVITE |
----------------------------------->|
| 2. MAR |
|<------------------|
| 3. MAA |
|------------------>|
| |
4. SIP 407 (Proxy |
Authentication Required) |
<-----------------------------------|
| |
5. SIP INVITE |
----------------------------------->|
| 6. MAR |
|<------------------|
| 7. MAA |
|------------------>| 8. SIP INVITE
| |---------------->
| | 9. SIP 200 (OK)
10. SIP 200 (OK) |<----------------
<-----------------------------------|
| |
Figure 4: SIP server requests authorization
5.5 Locating the recipient of the SIP request
Figure 5 shows the scenario where SIP server 1 may be configured as a
SIP edge proxy server, processing SIP traffic at the edge of a
network. SIP server 1 receives a SIP INVITE request (step 1). SIP
server 1 needs to find the address of SIP server 2, which is serving
the recipient of the SIP request. The Diameter client in SIP server
1 sends Diameter Location-Info-Request (LIR) message (step 2) to the
Diameter server. The Diameter server responds with a Diameter
Location-Info-Answer (LIA) message (step 3) that contains the SIP or
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SIPS URI of SIP server 2. SIP server 1 then forwards the SIP INVITE
to SIP server 2 (step 4). SIP server 2 will eventually forward the
SIP INVITE to the appropriate UAS (step 5).
+--------+ +--------+ +--------+
| SIP | |Diameter| | SIP |
|server 1| | server | |server 2|
+--------+ +--------+ +--------+
| | |
1. SIP INVITE | | |
-------------->| 2. LIR | |
|---------------->| |
| 3. LIA | |
|<----------------| |
| 4. SIP INVITE |
|--------------------------------->|
| | | 5. SIP INVITE
| | |-------------->
| | |
| | |
Figure 5: Locating the SIP server of the recipient
Although the example shows the connection between a SIP INVITE
request and the Diameter LIR message, any other SIP request other
than REGISTER (such as SUBSCRIBE, OPTIONS, etc.) would trigger the
same Diameter message (A SIP REGISTER request will trigger a Diameter
UAR message, as indicated in Figures Figure 2 and Figure 3.
The scenario described in this section is also applicable in case an
outbound SIP server is interested not in authenticating the user, but
requires to locate a further SIP server to route the outbound SIP
requests. In this case, the outbound SIP server is mapped to SIP
server 1 in Figure 5.
5.6 Update of the User Profile
The Diameter SIP application provides a mechanism for a Diameter
server to asynchronously download a user profile to a SIP server
whenever there is an update of such user profile. It must be noted
that the Diameter server also attaches the user profile in the
Diameter Server-Assignment-Answer (SAA) message. Although this is
valid for most of the daily situations, it may happen that the
administrator decides to update or modify the user profile for a
particular user, due to, e.g., new services made available to the
user. This may involve mechanisms outside the scope of this
specification, such as human intervention, in the Diameter server.
In this situation, the Diameter server is able to push the new user
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profile into the SIP server allocated to the user.
The scenario is illustrated in Figure 6. Where the user profile
changes, the Diameter server will send a Diameter
Push-Profile-Request (PPR) message (step 1) to the Diameter client in
the SIP server allocated to that user (SIP server 2 in the examples).
The Diameter PPR message will contain one or more SIP-User-Data AVP,
a User-Name AVP and zero or more SIP-AOR AVPs. The Diameter client
in SIP server 2 will acknowledge the Diameter PPR message by sending
a Diameter Push-Profile-Answer (PPA) message (step 2) to the Diameter
server.
+--------+ +--------+
|Diameter| | SIP |
| server | |server 2|
+--------+ +--------+
| |
| 1. PPR |
|------------------>|
| |
| 2. PPA |
|<------------------|
| |
Figure 6: Diameter server pushes an update of the user profile
5.7 SIP Soft State Termination
SIP can create soft states in SIP nodes based on, e.g., SIP
registrations or SIP event subscriptions. These states are
periodically refreshed, and cease to exist if they are not refreshed.
Additionally, an administrative action can be taken to terminate a
SIP soft state, or the SIP UA can explicitly terminate a SIP soft
state.
The Diameter base protocol offers a mechanism to create and delete
states in Diameter nodes. These states are called Diameter user
sessions. The Diameter server decides whether to use a Diameter user
session as a mechanism to map to a SIP soft state. If the Diameter
server decides to use Diameter user sessions, the termination of a
Diameter user session implies the termination of the corresponding
SIP soft state (e.g., registration, event subscription), and vice
versa. If the Diameter server does not use Diameter user sessions,
this Diameter SIP application offers specific commands to manage the
SIP soft states. Implementations compliant to this specification
MUST support both mechanisms of session management.
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We provide support for both Diameter client and Diameter server
initiated session termination.
Depending on whether Diameter sessions are used or not, termination
of a SIP soft state can be achieved by either of the following
methods:
When the Diameter client (SIP proxy) wants to terminate the SIP soft
state and Diameter user sessions are not maintained (i.e., the
Auth-Session-State AVP has been previously set to
NO_STATE_MAINTAINED), the Diameter client MUST send a
Server-Assignment-Request (SAR) message with the
SIP-Server-Assignment-Type AVP set to the value DE-REGISTRATION.
When the Diameter client (SIP proxy) wants to terminate the SIP soft
state and Diameter user sessions are maintained (i.e., the
Auth-Session-State AVP has been previously set to STATE_MAINTAINED)
the Diameter client MUST send a Session-Termination-Request message
as per regular procedures according to the RFC 3588 [RFC3588].
When the Diameter server wants to terminate the SIP soft state and
Diameter user sessions are not maintained (i.e., the
Auth-Session-State AVP has been previously set to
NO_STATE_MAINTAINED), the Diameter server MUST send a
Registration-Termination-Request message (see Section 7.9).
When the Diameter server wants to terminate the SIP soft state and
Diameter user sessions are maintained (i.e., the Auth-Session-State
AVP has been previously set to STATE_MAINTAINED), the Diameter server
MUST send an Abort-Session-Request message as per regular procedures
according to the RFC 3588 [RFC3588].
5.8 Diameter Server Discovery
The basic architecture assumption of this document is that all the
data related to a user is stored in a unique Diameter server. This
does not create a single point of failure, as it may be generally
thought. It is assumed that Diameter servers will be configured in a
redundant fashion as an attempt to mitigate the single point of
failure problem.
In large networks, where the number of users may be significantly
high, there might be a need to scale the number of Diameter servers.
All the data associated with a user will be still stored in one
Diameter server (typically operating in a redundant configuration).
But the data associated with different users may reside in different
Diameter servers.
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This configuration, although scales well, introduces a new problem,
namely: given the user's SIP AOR as an input, how to determine which
of various Diameter servers is storing the data for that particular
SIP AOR. We solve this problem by inspiring on the Diameter
redirection mechanism specified in RFC 3588 [RFC3588]. We include in
the architecture a new Diameter node that, for the purpose of this
document, it is known as Diameter Subscriber Locator (SL). The
Diameter Subscriber Locator contains a database or routing tables
that maps SIP AORs with Diameter server URIs. A particular Diameter
server URI points to the actual Diameter server that stores all the
data related to a particular SIP AOR, and in consequence, to the user
who owns the SIP AOR. The Diameter Subscriber Locator acts in a
similar way to a Diameter Redirect Agent, dispatching Diameter
requests (e.g., providing the redirection URI in the answer). The
Diameter Subscriber Locator can redirect all the request pertaining
to a user by setting the Redirect-Host-Usage AVP with a value
ALL_USER, as specified in RFC 3588 [RFC3588].
The Diameter SL can be replicated in different nodes along the
network, for the purpose of building scalability and redundancy. The
database or routing tables have to be consistent across all these
different Diameter SLs, so that equal Diameter requests will produce
the equal Diameter answers no matter which Diameter SL processes the
request.
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+--------+ +--------+ +--------+ +--------+
| SIP | |Diameter| |Diameter| | SIP |
|server 1| |SL red. | |server 1| |server 2|
+--------+ +--------+ +--------+ +--------+
| | | |
1. SIP INVITE| | | |
------------>| 2. LIR | | |
|---------->| | |
| 3. LIA | | |
|<----------| | |
| 4. LIR | |
|---------------------->| |
| 5. LIA | |
|<----------------------| |
| 6. SIP INVITE | |
|----------------------------------->| 7. SIP INVITE
| | | | ------------->
| | | |
Figure 7: Locating a Diameter server. SL redirecting requests
Figure 7 shows an example of operation of a Diameter Subscriber
Locator acting in redirect mode. SIP server 1 is receiving an INVITE
request (step 1) addressed (in the SIP Request-URI) to a user for
which the Diameter client in SIP server 1 does not posses routing
information. In other words, the Diameter client in SIP server 1
does not know the URI of Diameter server 1. The Diameter client
sends a Diameter LIR message (step 2) to any of the Diameter SLs
configured in the network. The address of those SLs is assumed to be
pre-provisioned in the Diameter client. The Diameter SL, based on
the contents of the SIP-AOR AVP and its own routing tables determines
the Diameter server that stores the information allocated to such
user. Then it builds a Diameter LIA message (step 3) that includes a
Result-Code AVP set to DIAMETER_REDIRECT_INDICATION and one or more
Redirect-Host AVPs, whose values are set to one or more URIs of
Diameter servers that store the information related to such user.
Then the Diameter client in SIP server 1 builds a new LIR message
(step 4) addressed to any of the Diameter servers received in the
Redirect-Host AVPs. The rest of procedure is completed as described
in previous sections.
6. Advertising Application Support
Diameter implementations conforming to this specification MUST
advertise its support by including an Auth-Application-Id AVP in the
Capabilities-Exchange-Request (CER) and Capabilities-Exchange-Answer
(CEA) commands, according to the Diameter base protocol, RFC 3588
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[RFC3588]. This Auth-Application-Id AVP MUST be set to the value of
this Diameter SIP application (Section 11.1 indicates the actual
value allocated by IANA).
7. Diameter SIP Application Command Codes
All the Diameter implementations conforming to this specification
MUST implement and support the list of Diameter commands listed in
Table 1.
+----------------------------------+-------+-------+----------------+
| Command Name | Abbr. | Code | Reference |
+----------------------------------+-------+-------+----------------+
| User-Authorization-Request | UAR | aaa | Section 7.1 |
| User-Authorization-Answer | UAA | aaa | Section 7.2 |
| Server-Assignment-Request | SAR | bbb | Section 7.3 |
| Server-Assignment-Answer | SAA | bbb | Section 7.4 |
| Location-Info-Request | LIR | ccc | Section 7.5 |
| Location-Info-Answer | LIA | ccc | Section 7.6 |
| Multimedia-Auth-Request | MAR | ddd | Section 7.7 |
| Multimedia-Auth-Answer | MAA | ddd | Section 7.8 |
| Registration-Termination-Request | RTR | eee | Section 7.9 |
| Registration-Termination-Answer | RTA | eee | Section 7.10 |
| Push-Profile-Request | PPR | fff | Section 7.11 |
| Push-Profile-Answer | PPA | fff | Section 7.12 |
+----------------------------------+-------+-------+----------------+
Table 1: Defined command codes
[Note to IANA and the RFC editor: replace aaa, bbb, ccc, and so on
with the actual values allocated to these commands.]
7.1 User-Authorization-Request (UAR) Command
The User-Authorization-Request (UAR) is indicated by the Command-Code
set to aaa and the Command Flags' 'R' bit set. The Diameter client
in a SIP server sends this command to the Diameter server to request
authorization for the SIP User Agent to route a SIP REGISTER request.
As the SIP REGISTER request implicitly carries a permission to bind
an AOR to a contact address, the Diameter client uses the Diameter
UAR as a first authorization request towards the Diameter server to
authorize the registration. For instance, the Diameter server can
verify that the AOR is a legitimate user of the realm.
The Diameter client in the SIP server will request authorization for
one of the possible values defined in the SIP-User-Authorization-Type
AVP (Section 8.10).
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The user name used for authentication of the user is conveyed in a
User-Name AVP (defined in the Diameter base protocol, RFC 3588
[RFC3588]). The location of the authentication user name in the SIP
REGISTER request varies depending on the authentication mechanism.
When the authentication mechanism is HTTP Digest as defined in RFC
2617 [RFC2617], the authentication user name is found in the
"username" directive of the SIP Authorization header field value.
This Diameter SIP application only provides support for HTTP Digest
authentication in SIP: other authentication mechanisms are not
currently supported.
The SIP or SIPS URI to be registered is conveyed in the SIP-AOR AVP
(Section 8.8). Typically this SIP or SIPS URI is found in the To
header field value of the SIP REGISTER request that triggered the
Diameter UAR message.
The SIP-Visited-Network-Id AVP indicates the network that is
providing SIP services (e.g., SIP proxy functionality or any other
kind of services) to the SIP User Agent.
Message Format
<UAR> ::= < Diameter Header: aaa, REQ, PXY >
< Session-ID >
< Auth-Application-Id >
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ SIP-AOR }
[ Destination-Host ]
[ User-Name ]
[ SIP-Visited-Network-Id ]
[ SIP-User-Authorization-Type ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]
7.2 User-Authorization-Answer (UAA) Command
The User-Authorization-Answer (UAA) is indicated by the Command-Code
set to aaa and the Command Flags' 'R' bit cleared. The Diameter
server sends this command in response to a previously received
Diameter User-Authorization-Request (UAR) command. The Diameter
server indicates the result of the requested registration
authorization. Additionally, the Diameter serve may indicate a
collection of SIP capabilities that assists the Diameter client to
select a SIP proxy to the AOR under registration.
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In addition to the values already defined in RFC 3588 [RFC3588], the
Result-Code AVP may contain one of the values defined in Section 9.1.
Whenever the Diameter server fails to process the Diameter UAR
message, it MUST stop processing and return the concerned error in
the Diameter UAA message. When there is success in the process, the
Diameter server MUST set the code to DIAMETER_SUCCESS in the Diameter
UAA message.
If the Diameter server requires a User-Name AVP value to process the
Diameter UAR request, but the Diameter UAR message did not contain a
User-Name AVP value, the Diameter server MUST set the Result-Code AVP
value to DIAMETER_USER_NAME_REQUIRED (see Section 9.1.2) and return
it in a Diameter UAA message. Upon reception of this Diameter UAA
message with the Result-Code AVP value set to
DIAMETER_USER_NAME_REQUIRED, the SIP server will typically request
authentication by generating a SIP 401 (Unauthorized) or SIP 407
(Proxy Authentication Required) response back to the originator.
When the authorization procedure succeeds, the Diameter server
constructs a User-Authorization-Answer (UAA) message that MUST
include the address of the SIP server already assigned to the user,
the capabilities needed by the SIP server (Diameter client) to select
another SIP server for the user or a combination of the previous two
options.
The Diameter UAA message contains the address of the SIP server
allocated to the user if the Diameter server is already aware of an
allocated SIP server to the user.
The Diameter UAA message contains the capabilities required by a SIP
server when there is a possibility that the Diameter client (in the
SIP server) needs to allocate another SIP server that will be
handling all the requests associated with this user, and possibly
triggering and executing services.
If a User-Name AVP is present in the Diameter UAR message, then the
Diameter server MUST verify the existence of the user in the realm,
i.e., the User-Name AVP value is a valid user within that realm. If
the Diameter server does not recognize the user name received in the
User-Name AVP, the Diameter server MUST build a Diameter
User-Authorization-Answer (UAA) message and MUST set the Result-Code
AVP to DIAMETER_ERROR_USER_UNKNOWN.
If a User-Name AVP is present in the Diameter UAR message, then the
Diameter server MUST authorize that User-Name AVP value is able to
register the SIP or SIPS URI included in the SIP-AOR AVP. If this
authorization fails, the Diameter server must set the Result-Code AVP
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to DIAMETER_ERROR_IDENTITIES_DONT_MATCH and send it in a Diameter
User-Authorization-Answer (UAA) message.
Correlation between User-Name and SIP-AOR AVP values is required
just to avoid that any user can register a SIP-AOR allocated to
another user.
If there is a SIP-Visited-Network-Id AVP in the Diameter UAR message,
and the SIP-User-Authorization-Type AVP value received in the
Diameter UAR message is set to REGISTRATION or
REGISTRATION&CAPABILITIES then the Diameter server SHOULD verify
whether the user is allowed to roam into the network specified in the
SIP-Visited-Network-Id AVP in the Diameter UAR message. If the user
is not allowed to roam into such network, the Diameter AAA server
MUST set the Result-Code AVP value in the Diameter UAA message to
DIAMETER_ERROR_ROAMING_NOT_ALLOWED.
If the SIP-User-Authorization-Type AVP value received in the Diameter
UAR message is set to REGISTRATION or REGISTRATION&CAPABILITIES then
the Diameter server SHOULD verify whether the SIP-AOR AVP value is
authorized to register in the home realm. Where the SIP Address of
Record is not authorized to register in the home realm, the Diameter
server MUST set the Result-Code AVP to
DIAMETER_AUTHORIZATION_REJECTED and send it in a Diameter UAA
message.
When the SIP-User-Authorization-Type AVP is not present in the
Diameter UAR message, or it is present and its value is set to
REGISTRATION then:
o If the Diameter server is not aware of any previous registration
of the user name (including registrations of other SIP Addresses
of Record allocated to the same user name), then the Diameter
server does not know of any SIP server allocated to the user. In
this case the Diameter server MUST set the Result-Code AVP value
to DIAMETER_FIRST_REGISTRATION in the Diameter UAA message, and
the Diameter server SHOULD include the required SIP server
capabilities in the SIP-Server-Capabilities AVP value in the
Diameter UAA message. The SIP-Server-Capabilities AVP will assist
the Diameter client (SIP server) to select an appropriate SIP
server for the user, according to the required capabilities.
o In some cases, the Diameter server is aware of a previously
assigned SIP server for the same or different SIP Addresses of
Record allocated to the same user name. In these cases,
re-assignment of a new SIP server may or may not be needed,
depending on the capabilities of the SIP server. The Diameter
server MUST always include the allocated SIP server URI in the
SIP-Server-URI AVP of the UAA message. If the Diameter server
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does not return the SIP capabilities, the Diameter server MUST set
the Result-Code AVP in the Diameter UAA message to
DIAMETER_SUBSEQUENT_REGISTRATION. Otherwise, if the Diameter
server includes a SIP-Server-Capabilities AVP then the Diameter
server MUST set the Result-Code AVP in the Diameter UAA message to
DIAMETER_SERVER_SELECTION. The Diameter client will then
determine, based on the received information, whether it needs to
select a new SIP server or not.
When the SIP-User-Authorization-Type AVP value received in the
Diameter UAR message is set to REGISTRATION&CAPABILITIES then
Diameter Server MUST return the list of capabilities in the
SIP-Server-Capabilities AVP value of the Diameter UAA message, it
MUST set the Result-Code to DIAMETER_SUCCESS and it MUST NOT return a
SIP-Server-URI AVP. The SIP-Server-Capabilities AVP enables the SIP
server (Diameter Client) to select another appropriate SIP server for
invoking and executing services for the user, depending on the
required capabilities. The Diameter server MAY leave the list of
capabilities empty to indicate that any SIP server can be selected.
When the SIP-User-Authorization-Type AVP value received in the
Diameter UAR message is set to DE-REGISTRATION then:
o If the Diameter server is aware of a SIP server assigned to the
SIP AOR under de-registration, the Diameter server MUST set the
Result-Code AVP to DIAMETER_SUCCESS and MUST set the
SIP-Server-URI AVP value to the known SIP server, and return them
in the Diameter UAA message.
o If the Diameter server is not aware of a SIP server assigned to
the SIP AOR under de-registration, then the Diameter server MUST
set the Result-Code AVP in the Diameter UAA message to
DIAMETER_ERROR_IDENTITY_NOT_REGISTERED.
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Message Format
<UAA> ::= < Diameter Header: aaa, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Session-State }
{ Result-Code }
{ Origin-Host }
{ Origin-Realm }
[ SIP-Server-URI ]
[ SIP-Server-Capabilities ]
[ Authorization-Lifetime ]
[ Auth-Grace-Period ]
* [ Redirect-Host ]
[ Redirect-Host-Usage ]
[ Redirect-Max-Cache-Time ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]
7.3 Server-Assignment-Request (SAR) Command
The Server-Assignment-Request (SAR) command is indicated by the
Command-Code set to bbb and the Command Flags' 'R' bit set. The
Diameter client in a SIP server sends this command to the Diameter
server to indicate the completion of the authentication process and
to request the Diameter server to store the URI of the SIP server
that is currently serving the user. The Diameter SAR command has the
main function to inform and store/clear in the Diameter server the
URI of the SIP server allocated to the user. Additionally, the
Diameter client can request to download the user profile or part of
it.
During the registration procedure, a SIP server becomes assigned to
the user. The Diameter client in the assigned SIP server MUST
include its own URI in the SIP-Server-URI AVP of the
Server-Assignment-Request (SAR) Diameter message and send it to the
Diameter server. The Diameter server then becomes aware of the
allocation of the SIP server and its URI.
The Diameter client in the SIP server MAY send a Diameter SAR message
because of other reasons. These reasons are identified in the
SIP-Server-Assignment-Type AVP value (Section 8.4). For instance, a
Diameter client in a SIP server may contact the Diameter server to
request de-registration of a user, to inform the Diameter server of
an authentication failure or just to download the user profile. For
a complete description of all the SIP-Server-Assignment-Type AVP
values see Section 8.4.
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Typically the reception of a SIP REGISTER request in a SIP server
will trigger the Diameter client in the SIP server to send the
Diameter SAR message. However, if a SIP server is receiving other
SIP request, such as INVITE, and the SIP server does not have the
user profile, the Diameter client in the SIP server may send the
Diameter SAR message to the Diameter server in order to download the
user profile and make the Diameter server aware of the SIP server
assigned to the user.
The user profile is an important piece of information that dictates
the behavior of the SIP server when triggering or providing services
for the user. Typically the user profile is divided into:
o Services to be rendered to the user when the user is registered
and initiates a SIP request.
o Services to be rendered to the user when the user is registered
and a SIP request destined to that user arrives to the SIP proxy.
o Services to be rendered to the user when the user is not
registered and a SIP request destined to that user arrives to the
SIP proxy.
The SIP-Server-Assignment-Type AVP will indicate the reason why the
Diameter client (SIP server) contacted the Diameter server. If the
Diameter client sets the SIP-Server-Assignment-Type AVP value to
REGISTRATION, RE_REGISTRATION, UNREGISTERED_USER, NO_ASSIGNMENT,
AUTHENTICATION_FAILURE or AUTHENTICATION_TIMEOUT, the Diameter client
MUST include exactly one SIP-AOR AVP in the Diameter SAR message.
The SAR message MAY contain zero or more SIP-Supported-User-Data-Type
AVPs. Each of them will contain a type of user data understood by
the SIP server. This allows the Diameter client to provide an
indication to the Diameter server of the different format of user
data understood by the SIP server. The Diameter server will use this
information to select one more SIP-User-Data AVPs that will be
included in the SAA message.
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Message Format
<SAR> ::= < Diameter Header: bbb, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ SIP-Server-Assignment-Type }
{ SIP-User-Data-Already-Available }
[ Destination-Host ]
[ User-Name ]
[ SIP-Server-URI ]
* [ SIP-Supported-User-Data-Type ]
* [ SIP-AOR ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]
7.4 Server-Assignment-Answer (SAA) Command
The Server-Assignment-Answer (SAA) is indicated by the Command-Code
set to bbb and the Command Flags' 'R' bit cleared. The Diameter
server sends this command in response to a previously received
Diameter Server-Assignment-Request (SAR) command. The response may
include the user profile or part of it, if requested.
In addition to the values already defined in RFC 3588 [RFC3588], the
Result-Code AVP may contain one of the values defined in Section 9.1.
The Result-Code AVP value in the Diameter SAA message may indicate a
success or an error in the execution of the Diameter SAR command. If
Result-Code AVP value in the Diameter SAA message does not contain an
error code, the SAA message MAY include one more SIP-User-Data AVPs
that will typically contain the profile of the user, indicating
services that the SIP server can provide to that user. The Diameter
server MAY include one or more SIP-Supported-User-Data-Type AVPs,
each one include an identifier of the supported user data formats a
the Diameter server. If the Diameter server does not include any
SIP-User-Data AVP then it SHOULD include one more
SIP-Supported-User-Data-Type AVPs indicating the list of supported
user data formats.
If the Diameter server requires a User-Name AVP value to process the
Diameter SAR request, but the Diameter SAR message did not contain a
User-Name AVP value, the Diameter server MUST set the Result-Code AVP
value to DIAMETER_USER_NAME_REQUIRED (see Section 9.1.2) and return
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it in a Diameter SAA message. Upon reception of this Diameter SAA
message with the Result-Code AVP value set to
DIAMETER_USER_NAME_REQUIRED, the SIP server will typically request
authentication by generating a SIP 401 (Unauthorized) or SIP 407
(Proxy Authentication Required) response back to the originator.
If the User-Name AVP is included in the Diameter SAR message, at
reception of the Diameter SAR message, the Diameter server MUST
verify the existence of the user in the realm, i.e., the User-Name
AVP value is a valid user within that realm. If the Diameter server
does not recognize the user name received in the User-Name AVP, the
Diameter server MUST build a Diameter Server-Assignment-Answer (SAA)
message and MUST set the Result-Code AVP to
DIAMETER_ERROR_USER_UNKNOWN.
Then the Diameter server MUST authorize that User-Name AVP value is a
valid authentication name for the SIP or SIPS URI included in the
SIP-AOR AVP of the Diameter SAR message. If this authorization
fails, the Diameter server must set the Result-Code AVP to
DIAMETER_ERROR_IDENTITIES_DONT_MATCH and send it in a Diameter
Server-Assignment-Answer (SAA) message.
The actions of the Diameter server at the reception of the Diameter
SAR message depends on the value of the SIP-Server-Assignment-Type:
o If the SIP-Server-Assignment-Type AVP value in the Diameter SAR
message is set to REGISTRATION or RE_REGISTRATION, the Diameter
server SHOULD verify that there is only one SIP-AOR AVP.
Otherwise, the Diameter server MUST answer with a Diameter SAA
message with the Result-Code AVP value set to
DIAMETER_AVP_OCCURS_TOO_MANY_TIMES and MUST NOT include any
SIP-User-Data AVP. If there is only one SIP-AOR AVP and if the
SIP-User-Data-Already-Available AVP value is set to
USER_DATA_NOT_AVAILABLE, then the Diameter server SHOULD include
one or more user profile data with the SIP or SIPS URI (SIP-AOR
AVP) and all other SIP identities associated with that AVP in the
SIP-User-Data AVP value of the Diameter SAA message. On selecting
the type of user data, the Diameter server SHOULD take into
account the supported formats at the SIP server
(SIP-Supported-User-Data-Type AVP in the SAR message) and the
local policy. Additionally, the Diameter server MUST set the
Result-Code AVP value to DIAMETER_SUCCESS in the Diameter SAA
message. The Diameter server considers the SIP AOR authenticated
and registered.
o If the SIP-Server-Assignment-Type AVP value in the Diameter SAR
message is set to UNREGISTERED_USER then the Diameter server MUST
store the SIP server address included in the SIP-Server-URI AVP
value. The Diameter server will return the SIP server address in
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Diameter Location-Info-Answer (LIA) messages. If the
SIP-User-Data-Already-Available AVP value is set to
USER_DATA_NOT_AVAILABLE, then the Diameter server SHOULD include
one or more user profile data associated with the SIP or SIPS URI
(SIP-AOR AVP) and associated identities in the SIP-User-Data AVP
value of the Diameter SAA message. On selecting the type of user
data, the Diameter server SHOULD take into account the supported
formats at the SIP server (SIP-Supported-User-Data-Type AVP in the
SAR message) and the local policy. The Diameter server MUST set
the Result-Code AVP value to DIAMETER_SUCCESS. The Diameter
server considers the SIP AOR UNREGISTERED, but with a SIP server
allocated to trigger and provide services for unregistered users.
Note that in case of UNREGISTERED_USER (SIP-Server-Assignment-Type
AVP), the Diameter server MUST verify that there is only one
SIP-AOR AVP. Otherwise, the Diameter server MUST answer the
Diameter SAR message with a Diameter SAA message, it MUST set the
Result-Code AVP value to DIAMETER_AVP_OCCURS_TOO_MANY_TIMES and
MUST NOT include any SIP-User-Data AVP.
If the User-Name AVP was not present in the Diameter SAR message
and the SIP-AOR is not known for the Diameter server, the Diameter
server MUST NOT include a User-Name AVP in the Diameter SAA
message and MUST set the Result-Code AVP value to
DIAMETER_ERROR_USER_UNKNOWN.
o If the SIP-Server-Assignment-Type AVP value in the Diameter SAR
message is set to TIMEOUT_DEREGISTRATION, USER_DEREGISTRATION,
DEREGISTRATION_TOO_MUCH_DATA or ADMINISTRATIVE_DEREGISTRATION the
Diameter server MUST clear the SIP server address associated with
all SIP Addresses of Record indicated in each of the SIP-AOR AVP
values included in the Diameter SAR message. The Diameter server
considers all of these SIP Addresses of Record as not registered.
The Diameter server MUST set the Result-Code AVP value to
DIAMETER_SUCCESS in the Diameter SAA message.
o If the SIP-Server-Assignment-Type AVP value in the Diameter SAR
message is set to TIMEOUT_DEREGISTRATION_STORE_SERVER_NAME or
USER_DEREGISTRATION_STORE_SERVER_NAME the Diameter server MAY keep
the SIP server address associated with the SIP Addresses of Record
included in the SIP-AOR AVP values of the Diameter SAR message,
even though the SIP Addresses of Record will become unregistered.
This feature allows a SIP server to request the Diameter server to
remain as an assigned SIP server for those SIP Addresses of Record
(SIP-AOR AVP values), and avoid SIP server assignment. The
Diameter server MUST consider all these SIP Addresses of Record as
not registered. If the Diameter server honors the request of the
Diameter client (SIP server) to remain as an allocated SIP server,
then the Diameter server MUST keep the SIP server assigned to
those SIP Addresses of Record and MUST set the Result-Code AVP
value to DIAMETER_SUCCESS in the Diameter SAA message. Otherwise,
when the Diameter server does not honor the request of the
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Diameter client (SIP server) to remain as an allocated SIP server,
the Diameter server MUST clear the SIP server name assigned to
those SIP Addresses of Record and it MUST set the Result-Code AVP
value to DIAMETER_SUCCESS_SERVER_NAME_NOT_STORED in the Diameter
SAA message.
o If the SIP-Server-Assignment-Type AVP value in the Diameter SAR
message is set to NO_ASSIGNMENT, the Diameter server SHOULD first
verify that the SIP-Server-URI AVP value in the Diameter SAR
message is the same URI as the as the one assigned to the SIP-AOR
AVP value. If they differ, then the Diameter server MUST set the
Result-Code AVP value to DIAMETER_UNABLE_TO_COMPLY in the Diameter
SAA message. Otherwise, if the SIP-User-Data-Already-Available
AVP value is set to USER_DATA_NOT_AVAILABLE, then the Diameter
server SHOULD include the user profile data with the SIP or SIPS
URI (SIP-AOR AVP) and all other SIP identities associated with
that AVP in the SIP-User-Data AVP value of the Diameter SAA
message. On selecting the type of user data, the Diameter server
SHOULD take into account the supported formats at the SIP server
(SIP-Supported-User-Data-Type AVP in the SAR message) and the
local policy.
o If the SIP-Server-Assignment-Type AVP value in the Diameter SAR
message is set to AUTHENTICATION_FAILURE or
AUTHENTICATION_TIMEOUT, the Diameter server MUST verify that there
is only SIP-AOR AVP in the Diameter SAR message. If the number of
occurrences of the SIP-AOR AVP is not exactly one, the Diameter
server MUST set the Result-Code AVP value to
DIAMETER_AVP_OCCURS_TOO_MANY_TIMES in the Diameter SAA message,
and SHOULD not take further actions. If there is exactly one
SIP-AOR AVP in the Diameter SAR message, the Diameter server MUST
clear the address of the SIP server assigned to the SIP Address of
Record, and the Diameter server MUST set the Result-Code AVP value
to DIAMETER_SUCCESS in the Diameter SAA message. The Diameter
server MUST consider the SIP AOR as not registered.
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Message Format
<SAA> ::= < Diameter Header: bbb, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Result-Code }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
* [ SIP-User-Data ]
[ SIP-Accounting-Information ]
* [ SIP-Supported-User-Data-Type ]
[ User-Name ]
[ Auth-Grace-Period ]
[ Authorization-Lifetime ]
* [ Redirect-Host ]
[ Redirect-Host-Usage ]
[ Redirect-Max-Cache-Time ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]
7.5 Location-Info-Request (LIR) Command
The Location-Info-Request (LIR) is indicated by the Command-Code set
to ccc and the Command Flags' 'R' bit set. The Diameter client in a
SIP server sends this command to the Diameter server to request
routing information, e.g., the URI of the SIP server assigned to a
particular user. The user is identified by the SIP-AOR AVP value.
Message Format
<LIR> ::= < Diameter Header: ccc, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ SIP-AOR }
[ Destination-Host ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]
7.6 Location-Info-Answer (LIA) Command
The Location-Info-Answer (LIA) is indicated by the Command-Code set
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to ccc and the Command Flags' 'R' bit cleared. The Diameter server
sends this command in response to a previously received Diameter
Location-Info-Request (LIR) command.
In addition to the values already defined in RFC 3588 [RFC3588], the
Result-Code AVP may contain one of the values defined in Section 9.1.
When the Diameter server finds an error in processing the Diameter
LIR message, the Diameter server MUST stop the process of the message
and answer with a Diameter LIA message that includes the appropriate
error code in the Result-Code AVP value. When there is no error, the
Diameter server MUST set the Result-Code AVP value to
DIAMETER_SUCCESS in the Diameter LIA message.
One of the errors that the Diameter server may find is that the
SIP-AOR AVP value is not a valid user in the realm. In such cases,
the Diameter server MUST set the Result-Code AVP value to
DIAMETER_ERROR_USER_UNKNOWN and return it in a Diameter LIA message.
If the Diameter server cannot process the Diameter LIR command, e.g.,
due to a database error, the Diameter server MUST set the Result-Code
AVP value to DIAMETER_UNABLE_TO_COMPLY and return it in a Diameter
LIA message. The Diameter server MUST NOT include any SIP-Server-URI
or SIP-Server-Capabilities AVP in the Diameter LIA message.
The Diameter server can or cannot be aware of a SIP server assigned
to the user contained in the SIP-AOR AVP value in the Diameter LIR
message. If the Diameter server is aware of a SIP server allocated
to that particular user, the Diameter server MUST include the URI of
such SIP server in the SIP-Server-URI AVP and return it in a Diameter
LIA message. This is typically the situation when the user is either
registered, or unregistered but there is a SIP server still assigned
to the user.
When the Diameter server is not aware of a SIP server allocated to
the user, typically the case when the user unregistered, the
Result-Code AVP value in the Diameter LIA message depends on whether
the Diameter server is aware that the user has services defined for
unregistered users or not:
o Those users who have services defined for unregistered users may
require the allocation of a SIP server to trigger and perhaps
execute those services. Therefore, when the Diameter server is
not aware of an assigned SIP server, but the user has services
defined for unregistered users, the Diameter server MUST set the
Result-Code AVP value to DIAMETER_UNREGISTERED_SERVICE and return
it in a Diameter LIA message. The Diameter server MAY also
include a SIP-Server-Capabilities AVP to facilitate the SIP server
(Diameter client) with the selection of an appropriate SIP server
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with the required capabilities. Absence of the
SIP-Server-Capabilities AVP will indicate to the SIP server
(Diameter client) that any SIP server is suitable to be allocated
for the user.
o Those users who do not have service defined for unregistered users
do not require further processing. The Diameter server MUST set
the Result-Code AVP value to
DIAMETER_ERROR_IDENTITY_NOT_REGISTERED and return it to the
Diameter client in a Diameter LIA message. The SIP server
(Diameter client) may return the appropriate SIP response (e.g.,
480 (Temporarily unavailable)) to the original SIP request.
Message Format
<LIA> ::= < Diameter Header: ccc, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Result-Code }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
[ SIP-Server-URI ]
[ SIP-Server-Capabilities ]
[ Auth-Grace-Period ]
[ Authorization-Lifetime ]
* [ Redirect-Host ]
[ Redirect-Host-Usage ]
[ Redirect-Max-Cache-Time ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]
7.7 Multimedia-Auth-Request (MAR) Command
The Multimedia-Auth-Request (MAR) command is indicated by the
Command-Code set to ddd and the Command Flags' 'R' bit set. The
Diameter client in a SIP server sends this command to the Diameter
server to request the Diameter server to authenticate and authorize a
user attempt to use some SIP service (in this context, SIP service
can be something as simple as a SIP subscription or using the proxy
services for a SIP request). Unlike the Diameter UAR command, MAR
does not store any state in the Diameter server.
The MAR command also registers the SIP server's own URI to the
Diameter server, so that future LIR/LIA messages can return this URI.
The SIP-Method AVP MUST include the SIP method name of the SIP
request that triggered this Diameter MAR message. The Diameter
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server can use this AVP to authorize some SIP requests depending on
the method.
The Diameter MAR message MUST include a SIP-AOR AVP. The SIP-AOR AVP
indicates the target of the SIP request. The value of the AVP is
extracted from different places in SIP request, depending on the
semantics of the SIP request. For SIP REGISTER messages the SIP-AOR
AVP value indicates the intended public user identity under
registration, and it is the SIP or SIPS URI populated in the To
header field value (addr-spec, according to the SIP ABNF) of the SIP
REGISTER request. For other types of SIP requests, such as INVITE,
SUBSCRIBE, MESSAGE, etc., the SIP-AOR AVP value indicates the
intended destination of the request. This is typically populated in
the Request-URI of the SIP request. It is the Diameter client
responsibility to extract the SIP-AOR AVP value from the proper SIP
header field. Extensions to SIP (new SIP methods or new semantics)
may require to extract the SIP-AOR from other parts of the request.
If the SIP request includes some sort of authentication information,
the Diameter client MUST include the user name, extracted from the
authentication information of the SIP request, in the User-Name AVP
value.
Message Format
<MAR> ::= < Diameter Header: ddd, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ SIP-AOR }
{ SIP-Method }
[ Destination-Host ]
[ User-Name ]
[ SIP-Server-URI ]
[ SIP-Number-Auth-Items ]
[ SIP-Auth-Data-Item ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]
7.8 Multimedia-Auth-Answer (MAA) Command
The Multimedia-Auth-Answer (MAA) is indicated by the Command-Code set
to ddd and the Command Flags' 'R' bit cleared. The Diameter server
sends this command in response to a previously received Diameter
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Multimedia-Auth-Request (MAR) command.
In addition to the values already defined in RFC 3588 [RFC3588], the
Result-Code AVP may contain one of the values defined in Section 9.1.
If the Diameter server requires a User-Name AVP value to process the
Diameter MAR request, but the Diameter MAR message did not contain a
User-Name AVP value, the Diameter server MUST set the Result-Code AVP
value to DIAMETER_USER_NAME_REQUIRED (see Section 9.1.2) and return
it in a Diameter MAA message. The Diameter server MAY include a
SIP-Number-Auth-Items AVP and one or more SIP-Auth-Data-Item AVPs
with authentication information (e.g., a challenge). Upon reception
of this Diameter MAA message with the Result-Code AVP value set to
DIAMETER_USER_NAME_REQUIRED, the SIP server will typically request
authentication by generating a SIP 401 (Unauthorized) or SIP 407
(Proxy Authentication Required) response back to the originator.
If the User-Name AVP is present in the Diameter MAR message, the
Diameter server MUST verify the existence of the user in the realm,
i.e., the User-Name AVP value is a valid user within that realm. If
the Diameter server does not recognize the user name received in the
User-Name AVP, the Diameter server MUST build a Diameter
Multimedia-Auth-Answer (MAA) message and MUST set the Result-Code AVP
to DIAMETER_ERROR_USER_UNKNOWN.
If the SIP-Methods AVP value of the Diameter MAR message is set to
REGISTER and a User-Name AVP is present, then the Diameter server
MUST authorize that User-Name AVP value is able to use the URI
included in the SIP-AOR AVP. If this authorization fails, the
Diameter server must set the Result-Code AVP to
DIAMETER_ERROR_IDENTITIES_DONT_MATCH and send it in a Diameter
Multimedia-Auth-Answer (MAA) message.
Correlation between User-Name and SIP-AOR AVP values is only
required for SIP REGISTER request, just to avoid that any user can
register a SIP-AOR allocated to another user. In other types of
SIP requests (e.g., INVITE), the SIP-AOR will indicate the
intended destination of the request, rather than the originator of
it.
Then Diameter server MUST verify whether the authentication scheme
(SIP-Authentication-Scheme AVP value) indicated in the grouped
SIP-Auth-Data-Item AVP is supported or not. If that authentication
scheme is not supported, then the Diameter server MUST set the
Result-Code AVP to DIAMETER_ERROR_AUTH_SCHEME_NOT_SUPPORTED and send
it in a Diameter Multimedia-Auth-Answer (MAA) message.
If the received Diameter MAR message contains a grouped
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SIP-Authorization AVP within the grouped SIP-Auth-Data-Item AVP, the
Diameter server considers that the authorization information is being
requested after a synchronization failure. In this case, the
sequence of the SIP-Auth-Data-Item AVPs would take into account the
SIP-Authorization AVP value to synchronize the vectors. The Diameter
server MUST set the Result-Code AVP to DIAMETER_SUCCESS.
If the SIP-Number-Auth-Items AVP is present in the Diameter MAR
message, it will indicate the number of authentication data items
that the Diameter client is requesting. It is RECOMMENDED that the
Diameter server, when building the Diameter MAA message, includes a
number of SIP-Auth-Data-Item AVPs that is a subset of the
authentication data items requested by the Diameter client in the
SIP-Number-Auth-Items AVP value of the Diameter MAR message.
If the SIP-Server-URI AVP is present in the Diameter MAR message,
then the Diameter server MUST compare the stored SIP server assigned
to the SIP AOR with the SIP-Server-URI AVP value received in the
Diameter MAR message. If there is not a match, the Diameter server
MUST update the stored SIP server assigned to the SIP AOR, and MUST
set an "authentication pending" flag for the SIP AOR. If there is a
match, the Diameter server shall clear the "authentication pending"
flag for the SIP AOR.
In any other situation, if there is a success in processing the
Diameter MAR command and the Diameter server stored the
SIP-Server-URI, the Diameter server MUST set the Result-Code AVP
value to DIAMETER_SUCCESS and return it in a Diameter MAA message.
If there is a success in processing the Diameter MAR command but the
Diameter server does not store the SIP-Server-URI because the AVP was
not present in the Diameter MAR command, then the Diameter server
MUST set the Result-Code AVP value to either:
1. DIAMETER_SUCCESS_AUTH_SENT_SERVER_NOT_STORED, if the Diameter
server is sending authentication vectors to create a challenge.
2. DIAMETER_SUCCESS_SERVER_NAME_NOT_STORED, if the Diameter server
successfully authenticated the user and authorized the SIP server
to proceed with the SIP request.
Otherwise, the Diameter server MUST set the Result-Code AVP value to
DIAMETER_UNABLE_TO_COMPLY and it MUST NOT include any
SIP-Auth-Data-Item AVP.
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Message Format
<MAA> ::= < Diameter Header: ddd, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Result-Code }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
[ User-Name ]
[ SIP-AOR ]
[ SIP-Number-Auth-Items ]
* [ SIP-Auth-Data-Item ]
[ Authorization-Lifetime ]
[ Auth-Grace-Period ]
* [ Redirect-Host ]
[ Redirect-Host-Usage ]
[ Redirect-Max-Cache-Time ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]
7.9 Registration-Termination-Request (RTR) Command
The Registration-Termination-Request (RTR) command is indicated by
the Command-Code set to eee and the Command Flags' 'R' bit set. The
Diameter server sends this command to the Diameter client in a SIP
server to indicate the SIP server that one or more SIP AORs have to
be de-registered. The command allows an operator to administratively
cancel the registration of a user from a centralized Diameter server.
The Diameter server has the capability to initiate the
de-registration of a user and inform the SIP server by means of the
Diameter RTR command. The Diameter server can decide whether only
one SIP AOR is going to be deregistered, a list of SIP AORs, or all
the SIP AORs allocated to the user.
The absence of a SIP-AOR AVP in the Diameter RTR message indicates
that all the SIP Addresses of Record allocated to the user identified
by the User-Name AVP are being deregistered.
The Diameter server MUST include a SIP-Deregistration-Reason AVP
value to indicate the reason for the deregistration.
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Message Format
<RTR> ::= < Diameter Header: eee, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Host }
{ SIP-Deregistration-Reason }
[ Destination-Realm ]
[ User-Name ]
* [ SIP-AOR ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]
7.10 Registration-Termination-Answer (RTA) Command
The Registration-Termination-Answer (RTA) is indicated by the
Command-Code set to eee and the Command Flags' 'R' bit cleared. The
Diameter client sends this command in response to a previously
received Diameter Registration-Termination-Request (RTR) command.
In addition to the values already defined in RFC 3588 [RFC3588], the
Result-Code AVP may contain one of the values defined in Section 9.1.
If the Diameter server requires a User-Name AVP value to process the
Diameter RTR request, but the Diameter RTR message did not contain a
User-Name AVP value, the Diameter server MUST set the Result-Code AVP
value to DIAMETER_USER_NAME_REQUIRED (see Section 9.1.2) and return
it in a Diameter RTA message. Upon reception of this Diameter RTA
message with the Result-Code AVP value set to
DIAMETER_USER_NAME_REQUIRED, the SIP server will typically request
authentication by generating a SIP 401 (Unauthorized) or SIP 407
(Proxy Authentication Required) response back to the originator.
The SIP server (Diameter client) will apply the administrative
deregistration to each of the URIs included in each of the SIP-AOR
AVP values, or, if there is no SIP-AOR AVP present in the Diameter
RTR request, to all the URIs allocated to the User-Name AVP value.
The value of the SIP-Deregistration-Reason AVP in the Diameter RTR
command will have an effect on the actions performed at the SIP
server (Diameter client):
o If the value is set to PERMANENT_TERMINATION, then the user has
terminated his/her registration to the realm. The SIP server
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(Diameter client), if supported through SIP procedures, SHOULD
inform the interested parties (e.g., subscribers to the
registration event) about the administrative de-registration and
SHOULD NOT request a new user registration. The SIP server SHOULD
clear the registration state of the de-registered AORs.
o If the value is set to NEW_SIP_SERVER_ASSIGNED, the Diameter
server informs the SIP server (Diameter client) that a new SIP
server has been allocated to the user, due to some reason. The
SIP server, if supported through SIP procedures, SHOULD inform the
interested parties (e.g., subscribers to the registration event)
about the administrative de-registration at this SIP server and
SHOULD NOT request a new user registration. The SIP server SHOULD
clear the registration state of the de-registered SIP AORs.
o If the value is set to SIP_SERVER_CHANGE, the Diameter server
informs the SIP server (Diameter client) that a new SIP server has
to be allocated to the user, due to e.g. user's capabilities
requiring a new SIP server, or not enough resources in the current
SIP server. The SIP server, if supported through SIP procedures,
SHOULD inform the interested parties (e.g., subscribers to the
registration event) about the administrative de-registration at
this SIP server and SHOULD request a new user registration. The
SIP server SHOULD clear the registration state of the
de-registered SIP AORs.
o If the value is set to REMOVE_SIP_SERVER, the Diameter server
informs the SIP server (Diameter client) that the SIP server will
no longer be bound in the Diameter server with such user. The SIP
server can delete all data related to the user.
Message Format
<RTA> ::= < Diameter Header: eee, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Result-Code }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
[ Authorization-Lifetime ]
[ Auth-Grace-Period ]
* [ Redirect-Host ]
[ Redirect-Host-Usage ]
[ Redirect-Max-Cache-Time ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]
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7.11 Push-Profile-Request (PPR) Command
The Push-Profile-Request (PPR) command is indicated by the
Command-Code set to fff and the Command Flags' 'R' bit set. The
Diameter server sends this command to the Diameter client in a SIP
server to update the user profile of an already registered user in
that SIP server. This allows an operator to modify the data of a
user profile and push it to the SIP server where the user is
registered.
Each user has a user profile associated with him/her. The profile
may change with time, due to, e.g., addition of new services to the
user. When the user profile changes, the Diameter server sends a
Diameter Push-Profile-Request (PPR) command to the Diameter client in
a SIP server, in order to start applying those new services.
A PPR command MAY contain a SIP-Accounting-Information AVP that
updates the addresses of the accounting servers. Changes in the
addresses of the accounting servers take effect immediately. The
Diameter client SHOULD close any existing accounting session with the
existing server an start providing accounting information to the
newly acquired accounting server.
The Diameter server sends the new user profile in one or more
SIP-User-Data AVP value. On selecting the type of user data, the
Diameter server SHOULD take into account the supported formats at the
SIP server (SIP-Supported-User-Data-Type AVP sent in a previous SAR
message) and the local policy.
The user to who the profile is applicable is indicated by the
User-Name AVP.
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Message Format
<PPR> ::= < Diameter Header: fff, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
* { SIP-User-Data }
{ User-Name }
[ SIP-Accounting-Information ]
[ Destination-Host ]
[ Authorization-Lifetime ]
[ Auth-Grace-Period ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]
7.12 Push-Profile-Answer (PPA) Command
The Push-Profile-Answer (PPA) is indicated by the Command-Code set to
fff and the Command Flags' 'R' bit cleared. The Diameter client
sends this command in response to a previously received Diameter
Push-Profile-Request (PPR) command.
In addition to the values already defined in RFC 3588 [RFC3588], the
Result-Code AVP may contain one of the values defined in Section 9.1.
If there is no error when processing the received Diameter PPR
message, the SIP server (Diameter client) MUST download the received
user profile from the SIP-User-Data AVP values in the Diameter PPR
message and store it associated with the user specified in the
User-Name AVP value.
If the SIP server does not recognize or does not support some of the
data transferred in the SIP-User-Data AVP values, the Diameter client
in the SIP server MUST return a Diameter PPA message that includes a
Result-Code AVP set to the value
DIAMETER_ERROR_NOT_SUPPORTED_USER_DATA.
If the SIP server (Diameter client) receives a Diameter PPR message
with a User-Name AVP that is unknown, the Diameter client MUST set
the Result-Code AVP value to DIAMETER_ERROR_USER_UNKNOWN and MUST
return it to the Diameter server in a Diameter PPA message.
If the SIP server (Diameter client) receives in the
SIP-User-Data-Content AVP value (of the grouped SIP-User-Data AVP)
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more data than it can accept, it MUST set the Result-Code AVP value
to DIAMETER_ERROR_TOO_MUCH_DATA and MUST return it to the Diameter
server in a Diameter PPA message. The SIP server MUST NOT override
the existing user profile with that received in the PPR message.
If the Diameter server receives the Result-Code AVP value set to
DIAMETER_ERROR_TOO_MUCH_DATA in a Diameter PPA message, it SHOULD
force a new re-registration of the user by sending to the Diameter
client a Diameter Registration-Termination-Request (RTR) with the
SIP-Deregistration-Reason AVP value set to SIP_SERVER_CHANGE. This
will force a re-registration of the user, and will trigger a
selection of a new SIP server.
If the Diameter client is not able to honor the command, for any
other reason, it MUST set the Result-Code AVP value to
DIAMETER_UNABLE_TO_COMPLY and it MUST return it in a Diameter PPA
message.
Message Format
<PPA> ::= < Diameter Header: fff, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Result-Code }
{ Auth-Session-State }
{ Origin-Host }
{ Origin-Realm }
* [ Redirect-Host ]
[ Redirect-Host-Usage ]
[ Redirect-Max-Cache-Time ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]
8. Diameter SIP Application AVPs
This section defines new AVPs used in this Diameter SIP application.
Applications compliant to this specification MUST implement these
AVPs.
Table 2 and Table 3 list the new AVPs defined in this Diameter SIP
application.
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+----------------------------------+------+-----------+-------------+
| AVP Name | AVP | Reference | Data-Type |
| | Code | | |
+----------------------------------+------+-----------+-------------+
| SIP-Accounting-Information | xx01 | Section | Grouped |
| | | 8.1 | |
| SIP-Accounting-Server-URI | xx02 | Section | DiameterURI |
| | | 8.1.1 | |
| SIP-Credit-Control-Server-URI | xx03 | Section | DiameterURI |
| | | 8.1.2 | |
| SIP-Server-URI | xx04 | Section | UTF8String |
| | | 8.2 | |
| SIP-Server-Capabilities | xx05 | Section | Grouped |
| | | 8.3 | |
| SIP-Mandatory-Capability | xx06 | Section | Unsigned32 |
| | | 8.3.1 | |
| SIP-Optional-Capability | xx07 | Section | Unsigned32 |
| | | 8.3.2 | |
| SIP-Server-Assignment-Type | xx08 | Section | Enumerated |
| | | 8.4 | |
| SIP-Auth-Data-Item | xx09 | Section | Grouped |
| | | 8.5 | |
| SIP-Authentication-Scheme | xx10 | Section | Enumerated |
| | | 8.5.1 | |
| SIP-Item-Number | xx11 | Section | Unsigned32 |
| | | 8.5.2 | |
| SIP-Authenticate | xx12 | Section | Grouped |
| | | 8.5.3 | |
| SIP-Authorization | xx13 | Section | Grouped |
| | | 8.5.4 | |
| SIP-Authentication-Info | xx14 | Section | Grouped |
| | | 8.5.5 | |
+----------------------------------+------+-----------+-------------+
Table 2: Defined AVPs, part 1
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+----------------------------------+------+-----------+-------------+
| AVP Name | AVP | Reference | Data-Type |
| | Code | | |
+----------------------------------+------+-----------+-------------+
| SIP-Number-Auth-Items | xx15 | Section | Unsigned32 |
| | | 8.6 | |
| SIP-Deregistration-Reason | xx16 | Section | Grouped |
| | | 8.7 | |
| SIP-Reason-Code | xx17 | Section | Enumerated |
| | | 8.7.1 | |
| SIP-Reason-Info | xx18 | Section | UTF8String |
| | | 8.7.2 | |
| SIP-AOR | xx19 | Section | UTF8String |
| | | 8.8 | |
| SIP-Visited-Network-Id | xx20 | Section | UTF8String |
| | | 8.9 | |
| SIP-User-Authorization-Type | xx21 | Section | Enumerated |
| | | 8.10 | |
| SIP-Supported-User-Data-Type | xx22 | Section | UTF8String |
| | | 8.11 | |
| SIP-User-Data | xx23 | Section | Grouped |
| | | 8.12 | |
| SIP-User-Data-Type | xx24 | Section | UTF8String |
| | | 8.12.1 | |
| SIP-User-Data-Contents | xx25 | Section | OctetString |
| | | 8.12.2 | |
| SIP-User-Data-Already-Available | xx26 | Section | Enumerated |
| | | 8.13 | |
| SIP-Method | xx27 | Section | UTF8String |
| | | 8.14 | |
+----------------------------------+------+-----------+-------------+
Table 3: Defined AVPs, part 2
[Note to IANA and the RFC editor: replace xx01, xx02, xx03, and so on
with the actual values allocated to these AVPs.]
8.1 SIP-Accounting-Information AVP
The SIP-Accounting-Information (AVP code TBD) is of type Grouped, and
contains the Diameter addresses of those nodes that are able to
collect accounting information. The Grouped Data field has the
following ABNF grammar:
SIP-Accounting-Information :: = < AVP Header: TBD >
* [ SIP-Accounting-Server-URI ]
* [ SIP-Credit-Control-Server-URI ]
* [ AVP]
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8.1.1 SIP-Accounting-Server-URI AVP
The SIP-Accounting-Server-URI AVP (AVP Code TBD) is of type
DiameterURI. This AVP contains the address of a Diameter server that
is able to receive SIP session related accounting information.
8.1.2 SIP-Credit-Control-Server-URI AVP
The Credit-Control-Server-URI AVP (AVP Code TBD) is of type
DiameterURI. This AVP contains the address of the a Diameter server
that is able to authorize real-time credit control usage. The
Diameter Credit Control Application [I-D.ietf-aaa-diameter-cc] may be
used for this purpose.
8.2 SIP-Server-URI AVP
The SIP-Server-URI AVP (AVP Code TBD) is of type UTF8String. This
AVP contains a SIP or SIPS URI (as defined in RFC 3261 [RFC3261])
that identifies a SIP server.
8.3 SIP-Server-Capabilities AVP
The SIP-Server-Capabilities AVP (AVP Code TBD) is of type Grouped.
The Diameter indicates in this AVP the requirements for a particular
SIP capability, so that the Diameter client (SIP server) is able to
select another appropriate SIP server to serve the user.
SIP-Server-Capability ::= < AVP Header: TBD >
* [ SIP-Mandatory-Capability ]
* [ SIP-Optional-Capability ]
* [ SIP-Server-URI ]
* [ AVP ]
8.3.1 SIP-Mandatory-Capability AVP
The SIP-Mandatory-Capability AVP (AVP Code TBD) is of type
Unsigned32. The value represents a certain capability (or set of
capabilities) that the SIP server to be allocated to the user has to
fulfil.
The semantics of the different values are not standardized, as it is
a matter of the administrative network to allocate its own semantics
within its own network. Each value has to represent a single
capability within the administrative network.
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8.3.2 SIP-Optional-Capability AVP
The SIP-Optional-Capability AVP (AVP Code TBD) is of type Unsigned32.
The value represents a certain capability (or set of capabilities)
that the SIP server to be allocated may, optionally, fulfil.
The semantics of the different values are not standardized, as it is
a matter of the administrative network to allocate its own semantics
within its own network. Each value has to represent a single
capability within the administrative network.
8.4 SIP-Server-Assignment-Type AVP
The SIP-Server-Assignment-Type AVP (AVP code TBD) is of type
Enumerated, and indicates the type of server update being performed
in a Diameter Server-Assignment-Request (SAR) operation. The
following values are defined:
o NO_ASSIGNMENT (0)
The Diameter client uses this value to request the user profile of
a SIP AOR, without affecting the registration state of such
identity.
o REGISTRATION (1)
First SIP registration of a SIP AOR.
o RE_REGISTRATION (2)
Subsequent SIP registration of a SIP AOR.
o UNREGISTERED_USER (3)
The SIP server has received a SIP request (e.g., SIP INVITE)
addressed for a SIP AOR that is not registered.
o TIMEOUT_DEREGISTRATION (4)
The SIP registration timer of an identity has expired.
o USER_DEREGISTRATION (5)
The SIP server has received a request to de-register a SIP AOR.
o TIMEOUT_DEREGISTRATION_STORE_SERVER_NAME (6)
The SIP registration timer of an identity has expired. The SIP
server keeps the user data stored and requests the Diameter server
to store the SIP server address.
o USER_DEREGISTRATION_STORE_SERVER_NAME (7)
The SIP server has received a user initiated de-registration
request. The SIP server keeps the user data stored and requests
the Diameter server to store the SIP server address.
o ADMINISTRATIVE_DEREGISTRATION (8)
The SIP server, due to administrative reasons, has de-registered a
SIP AOR.
o AUTHENTICATION_FAILURE (9)
The authentication of a user has failed.
o AUTHENTICATION_TIMEOUT (10)
The authentication timer has expired.
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o DEREGISTRATION_TOO_MUCH_DATA (11)
The SIP server has requested user profile information from the
Diameter server and has received a volume of data higher than it
can accept.
8.5 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 pertaining to a
user.
If the SIP-Auth-Data-Item is used to convey a SIP-Authenticate
grouped AVP, then the Diameter client MUST send a maximum of one
authentication data item (e.g., in case the SIP request contained
several credentials). Section 10 contains a detailed discussion and
normative text of the case when a SIP request contains several
credentials.
SIP-Auth-Data-Item :: = < AVP Header: TBD >
{ SIP-Authentication-Scheme }
[ SIP-Item-Number ]
[ SIP-Authenticate ]
[ SIP-Authorization ]
[ SIP-Authentication-Info ]
* [ AVP ]
8.5.1 SIP-Authentication-Scheme AVP
The SIP-Authentication-Scheme AVP (AVP code TBD) is of type
Enumerated and indicates the authentication scheme used in the
authentication of SIP services. RFC 2617 identifies this value as an
"auth-scheme" (see section 1.2 of RFC 2617 [RFC2617]). The only
currently defined value is:
o DIGEST (0) to indicate HTTP Digest authentication as specified in
RFC 2617 [RFC2617] Section 3.2.1. Derivative work is also
considered Digest authentication scheme, as long as the
"auth-scheme" is identified as Digest in the SIP headers carrying
the HTTP authentication. This includes, e.g., the HTTP Digest
authentication using AKA [RFC3310].
Each HTTP Digest directive (parameter) is transported in a
corresponding AVP, whose name follows the pattern Digest-*. The
Digest-* AVPs are RADIUS attributes imported from the RADIUS
Extension for Digest Authentication [ietf-radext-digest-auth]
namespace, allowing a smooth transition between RADIUS and Diameter
applications supporting SIP. The Diameter SIP application goes a
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step further by grouping the Digest-* AVPs into the SIP-Authenticate,
SIP-Authorization, and SIP-Authentication-Info grouped AVPs, that
correspond to the SIP Authenticate/Proxy-Authenticate,
Authorization/Proxy-authorization and Authentication-Info headers
fields, respectively.
NOTE: Due to the fact that HTTP Digest authentication [RFC2617] is
the only mandatory authentication mechanism in SIP, this memo only
provides support for HTTP Digest authentication and derivative
work such as HTTP Digest authentication using AKA [RFC3310].
Extensions to this memo can register new values and new AVPs to
provide support for other authentication schemes.
NOTE: Although RFC 2617 [RFC2617] defines the Basic and Digest
schemes for authenticating HTTP requests, RFC 3261 [RFC3261] only
imports HTTP Digest as a mechanism to provide authentication in
SIP.
8.5.2 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 of processing is relevant. The AVP indicates the order in
which the Grouped SIP-Auth-Data-Item should be processed. Lower
values of the SIP-Item-Number AVP indicate that the whole
SIP-Auth-Data-Item SHOULD be processed before other
SIP-Auth-Data-Item AVP that contain a higher value number in the
SIP-Item-Number AVP.
8.5.3 SIP-Authenticate AVP
The SIP-Authenticate AVP (AVP code TBD) is of type Grouped and
contains a reconstruction of either the SIP WWW-Authenticate or
Proxy-Authenticate header fields specified in RFC 2617 [RFC2617] for
the HTTP Digest authentication scheme. Additionally, the AVP may
include a Digest-HA1 AVP that contains H(A1) (as defined in RFC 2617
[RFC2617]). H(A1) allows the Diameter client to create an expected
response and compare it with the Digest response received from the
SIP UA.
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SIP-Authenticate ::= < AVP Header: TBD >
{ Digest-Realm }
{ Digest-Nonce }
[ Digest-Domain ]
[ Digest-Opaque ]
[ Digest-Stale ]
[ Digest-Algorithm ]
[ Digest-QoP ]
[ Digest-HA1]
* [ Digest-Auth-Param ]
* [ AVP ]
8.5.4 SIP-Authorization AVP
The SIP-Authorization AVP (AVP code TBD) is of type Grouped and
contains a reconstruction of either the SIP Authorization or
Proxy-Authorization header fields specified in RFC 2617 [RFC2617] for
the HTTP Digest authentication scheme.
SIP-Authorization ::= < AVP Header: TBD >
{ Digest-Username }
{ Digest-Realm }
{ Digest-Nonce }
{ Digest-URI }
{ Digest-Response }
[ Digest-Algorithm ]
[ Digest-CNonce ]
[ Digest-Opaque ]
[ Digest-QoP ]
[ Digest-Nonce-Count ]
[ Digest-Method]
[ Digest-Entity-Body-Hash ]
* [ Digest-Auth-Param ]
* [ AVP ]
8.5.5 SIP-Authentication-Info AVP
The SIP-Authentication-Info AVP (AVP Code TBD) is of type Grouped and
contains a reconstruction of the SIP Authentication-Info header
specified in RFC 2617 [RFC2617] for the HTTP Digest authentication
scheme.
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SIP-Authentication-Info ::= < AVP Header: TBD >
{ Digest-Nextnonce }
[ Digest-QoP ]
[ Digest-Response-Auth ]
[ Digest-CNonce ]
[ Digest-Nonce-Count ]
* [ AVP ]
Note that, in some cases, the Digest-Response-Auth AVP cannot be
calculated at the Diameter server, but has to be calculated at the
Diameter client (SIP server). For example, if the value of the
quality of protection (qop) parameter in Digest is set to "auth-int",
then the response-digest (rspauth parameter value in Digest) is
calculated with the hash of the body of the SIP response, which is
not available at the Diameter server. In this case, the Diameter
client (SIP server) must calculate the response-digest once the body
of the SIP response will be calculated.
Therefore, a value of "auth-int" in the Digest-QoP AVP of the
SIP-Authentication-Info AVP indicates that the Diameter client (SIP
server) MUST compute the Digest "rspauth" parameter value at the
Diameter client (SIP server).
8.5.6 Digest AVPs
The following AVPs are RADIUS attributes defined in the RADIUS
Extension for Digest Authentication [ietf-radext-digest-auth]:
Digest-AKA-Auts, Digest-Algorithm, Digest-Auth-Param, Digest-CNonce,
Digest-Domain, Digest-Entity-Body-Hash, Digest-HA1, Digest-Method,
Digest-Nextnonce, Digest-Nonce, Digest-Nonce-Count, Digest-Opaque,
Digest-QoP, Digest-Realm, Digest-Response, Digest-Response-Auth,
Digest-URI, Digest-Username, and Digest-Stale.
8.5.6.1 Considerations about Digest-HA1 AVP
The Digest-HA1 AVP contains the value, pre-calculated at the Diameter
server, of H(A1) as defined in RFC 2617 [RFC2617]. The Diameter
client can use H(A1) to calculate the expected Digest response,
according to this challenge. If the SIP UA is in possession of the
credentials, the calculated expected response and the response sent
from the SIP UA will match. The Diameter server MAY include this AVP
to enable and assist the SIP server in authenticating the SIP UA.
This pre-authentication mechanism is only applicable when the SIP UA
does not use client nonces (see below).
It is up to the Diameter server to include a Digest-HA1 AVP. The
Diameter server calculates the Digest H(A1) with the username,
password, realm, (and nonce and cnonce if applicable), as inputs, and
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places the result in the Digest-HA1 AVP value. For more details of
the A1 computation see RFC 2617 [RFC2617] Section 3.2.2.2. The
Diameter client can calculate the Digest expected response with H(A1)
as input, as described in RFC 2617 [RFC2617] Section 3.2.2.
Please note that the expected response calculation does not take into
account any client nonces, since the Diameter server does not have
them at the time of calculation. Therefore, the Diameter client MUST
NOT use the Digest-HA1 AVP if the SIP UA sent a expected response
based on client nonces (e.g., if the "qop" parameter is present in
the Digest header).
Section 10 provide further normative details about the usage of the
Digest-HA1 AVP.
8.5.6.2 Considerations about Digest-Entity-Body-Hash AVP
The Digest-Entity-Body-Hash AVP contains a hash of the entity body
contained in the SIP message. This hash is required by HTTP Digest
with quality of protection set to "auth-int". Diameter clients MUST
use this AVP to transport the hash of the entity body when HTTP
Digest is the authentication mechanism and the Diameter server
requires to verify the integrity of the entity body (e.g., qop
parameter set to "auth-int").
The clarifications described in Section 22.4 of RFC 3261 [RFC3261]
about the hash of empty entity bodies apply to the
Digest-Entity-Body-Hash AVP.
8.5.6.3 Considerations about Digest-Auth-Param AVP
The Digest-Auth-Param AVP (AVP code TBD) is of type UTF8String and is
the mechanism whereby the Diameter client and Diameter server can
exchange possible extension parameters contained in Digest headers
that are not understood by the Diameter client and for which there
are no corresponding stand-alone AVPs. Unlike the previously listed
Digest-* AVPs, the Digest-Auth-Param contains not only the value, but
also the parameter name, since the parameter name is unknown to the
Diameter client. The Diameter node MUST insert one Digest
parameter/value combination per AVP value. If the Digest header
contains several unknown parameters, then the Diameter implementation
MUST repeat this AVP and each instance MUST contain one different
unknown Digest parameter/value combination. This AVP corresponds to
the "auth-param" parameter defined in Section 3.2.1 of RFC 2617
[RFC2617].
Example: Assume that the Diameter server wants the SIP server to send
a "foo" parameter with the value set to "bar", so that the SIP server
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sends that combination in a SIP WWW-Authenticate header field. The
Diameter server builds a grouped SIP-Authenticate AVP that contains a
Digest-Auth-Param whose value is set to foo="bar". Then the SIP
server creates the WWW-Authenticate header field with all the digest
parameters (received in Digest-* AVPs) and adds the foo="bar"
parameter to that header field.
8.6 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 that the Diameter server included in a Diameter message.
When the AVP is present in a request, it indicates the number of
SIP-Auth-Data-Items the Diameter client is requesting. This can be
used, for instance, when the SIP server is requesting several
pre-calculated authentication vectors. In the answer message, the
SIP-Number-Auth-Items AVP indicates the actual number of items that
the Diameter server included.
8.7 SIP-Deregistration-Reason AVP
The SIP-Deregistration-Reason AVP (AVP Code TBD) is of type Grouped,
and indicates the reason for a deregistration operation.
SIP-Deregistration-Reason ::= < AVP Header: TBD >
{ SIP-Reason-Code }
[ SIP-Reason-Info ]
* [ AVP ]
8.7.1 SIP-Reason-Code AVP
The SIP-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:
o PERMANENT_TERMINATION (0)
o NEW_SIP_SERVER_ASSIGNED (1)
o SIP_SERVER_CHANGE (2)
o REMOVE_SIP_SERVER (3)
8.7.2 SIP-Reason-Info AVP
The SIP-Reason-Info AVP (AVP code TBD) is of type UTF8String, and
contains textual information that can be rendered to the user, about
the reason for a de-registration.
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8.8 SIP-AOR AVP
The SIP-AOR AVP (AVP Code TBD) is of type UTF8String. The syntax of
this AVP corresponds either to a SIP URI (with the format defined in
RFC 3261 [RFC3261]) or a TEL URI (with the format defined in RFC 3966
[RFC3966]).
The Diameter client (SIP server) uses the value found in a SIP
Request-URI or a header field value of the SIP request to construct
the SIP-AOR AVP. The selection of a Request-URI or a particular
header field depends on the semantics of the SIP message and whether
the SIP server is acting for originating or terminating requests.
For instance, when the SIP server receives an INVITE request
addressed to the served user, it maps the SIP Request-URI of the SIP
request to this AVP. However, when the SIP server receives an INVITE
request originated by the served user, it can map either the
P-Asserted-Identity or the From header field values to this AVP.
8.9 SIP-Visited-Network-Id AVP
The SIP-Visited-Network-Id AVP (AVP Code TBD) is of type UTF8String.
This AVP contains an identifier that helps the home network to
identify the visited network (e.g. the visited network domain name),
in order to authorize roaming to such visited network.
8.10 SIP-User-Authorization-Type AVP
The SIP-User-Authorization-Type AVP (AVP code TBD) is of type
Enumerated, and indicates the type of user authorization being
performed in a User Authorization operation, i.e., the Diameter
User-Authorization-Request (UAR) command. The following values are
defined:
o REGISTRATION (0)
This value is used in case of the initial registration or
re-registration.
This is the default value.
o DE_REGISTRATION (1)
This value is used in case of the de-registration.
o REGISTRATION_AND_CAPABILITIES (2)
This value is used in case of initial registration or
re-registration when the SIP server explicitly requests the
Diameter server to get capability information. This capability
information will help the SIP server to allocate another SIP
server to serve the user.
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8.11 SIP-Supported-User-Data-Type AVP
The SIP-Supported-User-Data-Type AVP (AVP Code TBD) is of type
UTF8String, and contains a string that identifies the type of
supported user data (user profile, see SIP-User-Data AVP (Section
8.12)) supported in the node. The AVP can be repeated, if the SIP
server supports several user data types. In case of repetition, the
Diameter client should order the different instances of this AVP
according to its preferences.
When the Diameter client inserts this AVP in a SAR message, it allows
the Diameter client to provide an indication to the Diameter server
of the types of user data supported by the SIP server. The Diameter
server, upon inspection of these AVPs, will return a suitable
SIP-User-Data AVP (Section 8.12) of the type indicated in the
SIP-User-Data-Type AVP (Section 8.12.1).
The Diameter server SHOULD include a SIP-Supported-User-Data-Type AVP
in a Diameter SAA message if none of the supported user data types at
the SIP server in the Diameter client are supported at the Diameter
server, and thus, there is not SIP-User-Data AVP included in the SAA
message. This indication is merely for debugging reasons, since
there is not a fallback mechanism that allows the Diameter client to
retrieve the profile in a supported format.
The Diameter server MAY always include one or more
SIP-Supported-User-Data-Type AVPs to indicate the list of supported
user data types.
8.12 SIP-User-Data AVP
The SIP-User-Data AVP (AVP Code TBD) is of type Grouped. This AVP
allows the Diameter server to transport user specific data, such as a
user profile, to the SIP server (in the Diameter client). The
Diameter server selects a type of user data that is understood by the
SIP server in the Diameter client, and has been indicated in a
SIP-Supported-User-Data-Type AVP. In case the Diameter client
indicated support for several types of user data, the Diameter server
SHOULD choose the first type supported by the client.
The SIP-User-Data grouped AVP contains a SIP-User-Data-Type AVP, that
indicates the type of user data included in the
SIP-User-Data-Contents-AVP.
SIP-User-Data ::= < AVP Header: TBD >
{ SIP-User-Data-Type }
{ SIP-User-Data-Contents }
* [ AVP ]
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8.12.1 SIP-User-Data-Type AVP
The SIP-User-Data AVP (AVP Code TBD) is of type UTF8String, and
contains a string that identifies the type of user data included in
the SIP-User-Data AVP (Section 8.12).
This document does not specify a convention to characterize the type
of user data contained in the SIP-User-Data AVP (Section 8.12). It
is believed that in most cases this feature will be used in
environments controlled by a network administrator who can configure
both the client and server to assign the same value type at the
client and server. It is also RECOMMENDED that organizations
developing their own profile of SIP-User-Data AVP (Section 8.12)
allocate a type based on their canonical DNS name. For instance,
organization "example.com" can define several types of SIP-User-Data
an allocate the types "type1.dsa.example.com",
"type2.dsa.example.com", and so on. This convention will avoid clash
in the allocation of types of SIP-User-Data AVP (Section 8.12).
This AVP MUST always be included when a SIP-User-Data AVP is also
included in a Diameter command.
8.12.2 SIP-User-Data-Contents AVP
The SIP-User-Data AVP (AVP Code TBD) is of type OctetString. The
Diameter peers do not need to understand the value of this AVP.
The AVP contains the user profile data required for a SIP server to
give service to the user.
8.13 SIP-User-Data-Already-Available AVP
The SIP-User-Data-Already-Available AVP (AVP code TBD) is of type
Enumerated, and gives an indication to the Diameter server about
whether the Diameter client (SIP server) already got the portion of
the user profile that it needs to serve the user. The following
values are defined:
o USER_DATA_NOT_AVAILABLE (0)
The Diameter client (SIP server) does not have the data that it
needs to serve the user.
o USER_DATA_ALREADY_AVAILABLE (1)
The Diameter client (SIP server) already has got the data that it
needs to serve the user.
8.14 SIP-Method AVP
The SIP-Method-AVP (AVP code TBD) is of type UTF8String and contains
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the method of the SIP request that triggered the Diameter message.
The Diameter server MUST use this AVP solely to for authorization of
SIP requests, and MUST NOT use it to compute the Digest
authentication. To compute the Digest authentication, the Diameter
server MUST use the Digest-Method AVP instead.
9. New Values for Existing AVPs
This section defines new values that the Diameter SIP application
extends to already existing AVPs.
9.1 Extension to the Result-Code AVP Values
The Result-Code AVP is already defined in RFC 3588 [RFC3588]. In
addition to the values already defined in RFC 3588 [RFC3588], the
Diameter SIP application defines the following new Result-Code AVP
values:
9.1.1 Success Result-Code AVP Values
A Diameter peer uses Result-Code AVP values that fall into the
success category to inform the remote peer that a request has been
successfully completed.
o DIAMETER_FIRST_REGISTRATION 2xx1
The user was not previously registered. The Diameter server has
now authorized the registration.
o DIAMETER_SUBSEQUENT_REGISTRATION 2xx2
The user is already registered. The Diameter server has now
authorized the re-registration.
o DIAMETER_UNREGISTERED_SERVICE 2xx3
The user is not currently registered, but the requested service
can still be granted to the user.
o DIAMETER_SUCCESS_SERVER_NAME_NOT_STORED 2xx4
The request operation was successfully processed. The Diameter
server does not keep a record of the SIP server address assigned
to the user.
o DIAMETER_SERVER_SELECTION 2xx5
The Diameter server has authorized the registration. The user has
already a SIP server assigned, but it may be necessary to select a
new SIP server for the user.
o DIAMETER_SUCCESS_AUTH_SENT_SERVER_NOT_STORED 2xx6
The requested operation was successfully executed. The Diameter
server is sending authentication vectors in the answer message.
The Diameter server does not keep a record of the SIP server.
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9.1.2 Transient Failures Result-Code AVP Values
A Diameter peer uses a Result-Code AVP value that falls in the
transient failures category to inform the remote peer that a request
could not be satisfied at the time it was received, but MAY be able
to satisfy the request in the future.
o DIAMETER_USER_NAME_REQUIRED 4xx1
The Diameter request did not contain a User-Name AVP, and it is
required to complete the transaction. The Diameter peer MAY
attempt the request again including a User-Name AVP.
9.1.3 Permanent failures Result-Code AVP Values
A Diameter peer uses a Result-Code AVP value that fall into the
permanent failure category to inform the remote peer that the request
failed and should not be attempted again.
o DIAMETER_ERROR_USER_UNKNOWN 5xx1
The SIP-AOR AVP value does not belong to a known user in this
realm.
o DIAMETER_ERROR_IDENTITIES_DONT_MATCH 5xx2
The value in one of the SIP-AOR AVPs is not allocated to the user
specified in the User-Name AVP.
o DIAMETER_ERROR_IDENTITY_NOT_REGISTERED 5xx3
A query for location information is received for a SIP AOR that
has not been registered before. The user to which this identity
belongs cannot be given service in this situation.
o DIAMETER_ERROR_ROAMING_NOT_ALLOWED 5xx4
The user is not allowed to roam to the visited network.
o DIAMETER_ERROR_IDENTITY_ALREADY_REGISTERED 5xx5
The identity being registered has already a server assigned and
the registration status does not allow that it is overwritten.
o DIAMETER_ERROR_AUTH_SCHEME_NOT_SUPPORTED 5xx6
The authentication scheme indicated in an authentication request
is not supported.
o DIAMETER_ERROR_IN_ASSIGNMENT_TYPE 5xx7
The SIP server address sent in the SIP-Server-URI AVP value of the
Diameter Server-Assignment-Request (SAR) command is the same SIP
server address that is currently assigned, but the
SIP-Server-Assignment-Type AVP is not allowed, e.g., the user is
registered and the Server-Assignment-Request indicates the
assignment for an unregistered user.
o DIAMETER_ERROR_TOO_MUCH_DATA 5xx8
The Diameter peer in the SIP server receives more data than it can
accept. The SIP server cannot overwrite the already stored data.
o DIAMETER_ERROR_NOT SUPPORTED_USER_DATA 5xx9
The SIP server informs Diameter server that the received
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subscription data contained information which was not recognized
or supported.
10. Authentication Details
Authenticating a user can occur through various mechanisms.
Currently HTTP Digest authentication is supported. The actual
authentication is performed in either the SIP server or the Diameter
server.
If the Diameter server wants to retain authentication of the user, it
MUST NOT include a Digest-HA1 AVP (part of the grouped
SIP-Authenticate AVP which in turn is part of the SIP-Auth-Data-Item
AVP) in a MAA message. The Diameter server MAY include a
pre-calculated Digest-HA1 AVP in the MAA message if it wants to
delegate authentication of the user to the SIP server.
The fact that the SIP server is enabled to perform authentication
(i.e., the Digest-HA1 AVP is available to the SIP server) is not
enough to conclude that authentication will take place in the SIP
server. It might be still possible that the SIP UA includes client
nonces in the expected response (e.g., "qop" parameter present in the
Digest header), in which case the pre-calculated expected response is
not valid anymore. In this case the SIP server MUST request
authentication to the Diameter server and MUST send a MAR message to
the Diameter server, which includes a grouped SIP-Authorization AVP
(part of the grouped SIP-Auth-Data-Item AVP) that mimics the Digest
header containing the credentials.
When requesting authentication, the Diameter client indicates in the
SIP-Number-Auth-Items AVP value of a Diameter MAR message how many
authentication vectors are being requested. In the Diameter MAA
message, the Diameter server SHOULD indicate how many instances of
SIP-Auth-Data-Item AVPs are present with the SIP-Number-Auth-Items
AVP. This number may be different from the one requested in the
Diameter MAR message. If multiple SIP-Auth-Data-Item AVPs are
present, and their ordering is significant, the Diameter server MUST
include a SIP-Item-Number AVP in each grouping to indicate the order.
The SIP-Authentication-Scheme and SIP-Authenticate AVPs will contain
data (typically a challenge of some kind) which the user can use for
her authentication. The grouped SIP-Authorization AVP will contain
the AVPs that conform the response which is expected from the user.
If the Diameter server performs the authentication of the user, the
Diameter MAR message that the Diameter client sends to the Diameter
server MUST include all the authentication credentials supplied by
the SIP UA (there might be more than one credential, e.g., different
realms, authentication of proxies, etc.). Each credential is
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inserted in a grouped SIP-Authorization AVP (part of the grouped
SIP-Auth-Data-Item AVP). The Diameter client MUST insert a
SIP-Number-Auth-Items AVP with the value set to the number of
credentials enclosed. If necessary, the Digest-Entity-Body-Hash AVP
will contain a hash of the body, needed to perform the
authentication. If the authentication is successful, the Diameter
MAA message will contain a Result-Code AVP indicating success, and if
necessary, the Diameter server MAY include one or more
SIP-Auth-Data-Item AVPs to provide further authentication vectors to
the SIP server. If the authentication is unsuccessful due to missing
credentials, the Diameter MAA message will include an
SIP-Auth-Data-Item AVP with the SIP-Authentication-Scheme and
SIP-Authenticate AVPs containing data (typically a challenge of some
kind) that the user can use to authenticate itself.
There are situation where a SIP request traverses several proxies,
and each of the proxies request to authenticate the SIP UA. In this
situation, it is a valid scenario that a SIP request received at a
SIP server contains several sets of credentials. The 'realm'
directive in HTTP is the key that the Diameter client can use to
determine which credential is applicable. It may happen also that
none of the realms are of interests to the Diameter client, in which
case the Diameter client MUST consider that no credentials (of
interest) were sent. In any case, a Diameter client MUST send zero
or exactly one credential to the Diameter server. The Diameter
client MUST choose the credential based on the 'realm' directive in
the Authorization/Proxy-Authorization header field, and it MUST match
the realm of the Diameter client.
11. IANA Considerations
This document serves as IANA registration request for a number of
items that should be registered in the AAA parameters registry.
11.1 Application Identifier
This document defines a standards-track Application-ID that falls
into the Application Identifier standards-track address space defined
by RFC 3588 [RFC3588] Section 11.3. This Application ID should be
registered in the Application IDs sub-registry of the AAA parameters
registry with the following data:
ID values Name Reference
----------- ------------------------ ---------
XXX Diameter Session Intiation [RFC YYYY]
Protocol (SIP) application
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[IANA to replace XXX with the allocated number, YYYY with the RFC
number of this specification]
11.2 Command Codes
This document defines new standard commands, whose Command Codes are
to be allocated within the standard permanent Command Codes address
space defined n RFC 3588 [RFC3588] Section 11.2.1. These command
codes should be registered in the Command Codes sub-registry of the
AAA parameters registry.
Table 1 in Section 7 contains the detailed list of Command Code names
and values that are part of this Diameter application.
11.3 AVP Codes
This document defines new standard AVPs, whose AVP Codes are to be
allocated within the AVP Codes address space defined in RFC 3588
[RFC3588] Section 11.4. These AVP codes should be registered in the
AVP Codes sub-registry of the AAA parameters registry.
Table 2 and Table 3 in Section 8 contains the detailed list of AVP
names and AVP codes that are part of this Diameter application.
11.4 Additional Values for the Result-Code AVP Value
This document defines new standard Result-Code AVP values to be
allocated within the Result-Code AVP address space defined in RFC
3588 [RFC3588] Section 14.4.1. These values should be listed in the
Result-Code AVP values section of the AVP Specific Values
sub-registry of the AAA parameters registry.
Section 9.1.1 lists the new Result-Code AVP values that fall into the
success category, according to RFC 3588 [RFC3588] Section 7.1.2.
Section 9.1.2 lists the new Result-Code AVP values that fall into the
transient failure category, according to RFC 3588 [RFC3588] Section
7.1.4.
Section 9.1.3 lists the new Result-Code AVP values that fall into the
permanent failures category, according to RFC 3588 [RFC3588] Section
7.1.5.
12. Security Considerations
This memo does not describe a stand-alone protocol, but a particular
application for the Diameter protocol [RFC3588]. Consequently, all
the security considerations applicable to Diameter automatically
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apply to this memo. In particular, section 13 of RFC 3588 applies to
this memo.
This Diameter SIP application allows a Diameter client to use the
properties of HTTP Digest authentication [RFC2617] by evaluating or
sending to the Diameter server the credentials supplied by a user.
When Section 4 of RFC 2617 [RFC2617] discusses HTTP Digest
authentication, it is also applicable to this memo.
This Diameter SIP application also allows a Diameter client to use
the properties of HTTP Digest authentication using AKA [RFC3310] by
evaluating or sending to the Diameter server the credentials supplied
by a user. Section 5 of RFC 3310 [RFC3310] is also applicable to
this memo.
13. Contributors
The authors would like to thank the following contributors who made
substantial contributions to this work:
Pete McCann Lucent
Jaako Rajaniemi Nokia
14. Acknowledgements
The authors would like to thank Tony Johansson and Kevin Purser for
their invaluable contribution to the start up of this application and
the continuous progress. The authors would like to thank Daniel
Warren, Jayshree Bharatia, Kuntal Chowdhury, Jari Arkko, Avi Lior,
Wolfgang Beck, and Ulrich Wiehe for their valuable comments.
The Diameter SIP Application is based on the Diameter Application for
the Cx interface of the 3GPP IP Multimedia Subsystem [3GPP.29.229].
The authors would like to thank 3GPP Working Group CN4 for this work.
15. Changes With Respect Previous Versions
Note to the RFC editor: Delete this section before publication as
RFC.
15.1 Changes in draft-ietf-aaa-diameter-sip-app-05.txt from -04.txt
o The Digest-* AVPs are imported from the the RADIUS Extension for
Digest Authentication [ietf-radext-digest-auth]. An introduction
paragraph has been added in Section 8.5.1.
o As a side effect of the above change, the
SIP-Authentication-Context disappeared. This was a grouped AVP
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that only contained a Digest-Entity-Body-Hash AVP. The latter
will remain (in the RADIUS draft).
o The Digest-Expected-Response was considered not secure enough.
Instead, the Digest-Expected-Response has been replaced by
Digest-HA1, which contains a hash of A1 (see RFC 2617 [RFC2617]
Section 3.2.2 for more details. This allows the Diameter server
to delegate the final authentication to the Diameter client in a
secure way. The Digest-HA1 AVP is also imported from RADIUS
Extension for Digest Authentication [ietf-radext-digest-auth].
o The Digest-Digest-URI has been renamed as Digest-URI, as it is now
imported from RADIUS Extension for Digest Authentication
[ietf-radext-digest-auth].
o The SIP-Accounting-Information AVP was originally specified in the
SAA command. It has been also added to the PPR command, so that
it is possible that PPR updates the addresses of the accounting
servers.
o It has been clarified that when the Diameter client receives a
answer command that contains the Result-Code AVP set to
DIAMETER_USER_NAME_REQUIRED the SIP server will typically request
authentication. Previously, the description seemed to indicate
that this typical action applied to any Result-Code.
o The TEL URI (RFC 2806bis) is now known as RFC 3966.
o If multiple SIP proxies are authenticating the user, the SIP
request may contain several Proxy-Authorization headers. The
Diameter server cannot send all the credentials, since the
Diameter server may be serving several common realms for which
credentials exist. In this situation the Diameter server will not
known which credentials to use. It has been clarified that the
Diameter client MUST send only one set of credentials at a time,
those belonging to the served realm.
o Reference added to RFC 3588 when a Subscriber Locator Function can
populate the Redirect-Host-Usage with the value ALL_USER.
o The IANA registration section has clarified what are the registry
and sub-registries where IANA needs to take an action.
15.2 Changes in draft-ietf-aaa-diameter-sip-app-04.txt from -03.txt
o DIAMETER_SUCCESS_SERVER_NAME_NOT_STORED and
DIAMETER_SUCCESS_SERVER_NOT_STORED have the same semantics: the
former is kept, the latter is deleted.
o Added a new Digest-Method AVP. This AVP contains the method used
to compute the Digest authentication, and it is independent from
the SIP-Method AVP. It has been clarified that Digest-Method is
used for authentication whereas SIP-Method is used for
authorization.
o SIP-User-Data-Request-Type AVP is removed. Its purpose was to
retrieve a fraction of the user profile. This seems to create
expensive complexity, and we don't seem to have requirements to
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support this function anymore.
o Fixed the general section layout. Some sections got, by accident,
buried in deep level section.
o The grouped SIP-Authenticate AVP allowed multiple instances of the
Digest-Expected-Response AVP. However, since there can be only
one expected response computed at the Diameter server, we now
allow a single Digest-Expected-Response.
o A note is added indicating that if Digest-Qop is set to "auth-int"
in the SIP-Authentication-Info AVP, then the Diameter client (SIP
server) is responsible to compute the "rspauth" value in the
Digest Authentication-Info header.
o This version of the draft provides support to identify the type of
user data included in the SIP-User-Data AVP (this can contain a
user profile). The following changes has been made:
o
* Added a new SIP-Supported-User-Data-Type AVP.
* The old SIP-User-Data AVP is now a grouped AVP that contains
two AVPs: SIP-User-Data-Type and SIP-User-Data-Contents.
* Added a new SIP-User-Data-Type AVP.
* Added a new SIP-User-Data-Contents (that contains the profile).
This is equivalent to the old SIP-User-Data AVP.
* All the above AVPs are visible in SAR, SAA, and PPR commands.
* The new SIP-User-Data and SIP-Supported-User-Data-Type allows
repetition (a server could potential send more than one
profile; a client can express support for more than one type of
profile).
o Fixed a typo that defined the SIP-Visited-Network-Id AVP as an
OctetString AVP rather than UTF8.
15.3 Changes in draft-ietf-aaa-diameter-sip-app-03.txt from -02.txt
o A Diameter Subscriber Locator was either a Diameter Relay or a
Diameter Redirect node. We have removed the Diameter Relay
functionality, since Diameter relays will not relay CER/CEA
messages, thus, a Diameter client will never be able to determine
which Diameter applications are running in a given Diameter
server. So a Diameter Subscriber Locator is implemented as a
Diameter redirect node.
o Section "Registration termination" has been rewritten. Now the
procedures speak about SIP soft state management, rather than SIP
registration, so this procedures are applicable to SIP event
subscriptions as well. A discussion on how to couple Diameter
user sessions with SIP soft states is also added
o Added a new Digest-Expected-Response AVP that allows the Diameter
server to send a pre-calculated expected digest response to the
Diameter client. This is only applicable to the case when the SIP
UA does not use client nonces.
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o The Authentication Details Section has been updated with the
latest details of the authentication process.
15.4 Changes in draft-ietf-aaa-diameter-sip-app-02.txt from -01.txt
o We have changed the type of the SIP-Authenticate,
SIP-Authorization, SIP-Authentication-Info AVPs. Now, each is a
grouped AVP and contains one or more AVPs that maps to the
corresponding Digest parameter. This means that the Diameter
server will receive in a different AVP each of the values of the
different parameters contained in the Digest headers. This
approach relieves the Diameter server of implementing a SIP parser
to determine the values of each of the parameters.
o Specifically added support for Digest AKA operation, as per RFC
3310 [RFC3310]. A Digest-AKA-Auts AVP is added.
o List of authors trimmed. Contributors section added.
o The SIP-Entity-Body-Hash is renamed to Digest-Entity-Body-Hash to
be aligned with the rest of the Digest-* AVPs.
o The NAS-Session-Key AVP has been deleted. We never knew why this
AVP was here.
o We have removed the support for key distribution. Specifically we
have removed the Confidentiality-Key and Integrity-Key AVPs.
15.5 Changes in draft-ietf-aaa-diameter-sip-app-01.txt from -00.txt
o The SIP-Authentication-Info AVP was mistakenly typed as
OctetString. We changed it to UTF8String. Since SIP is encoded
in UTF8String, there is no point in having an OctetString AVP
here.
o The SIP-Authentication-Context AVP is changed to be a grouped AVP.
It contains an SIP-Entity-Body-Hash AVP that contains the hash of
the entity body (e.g., the hash of the SDP). This is because some
authentication mechanisms require to make a hash of the entity
body. Instead of sending the whole entity body to the Diameter
server, it is more efficient to send the hash of the body.
o Added an descriptive text indicating the intended use/actions of
each command.
o Removed references to PGP since it is deprecated in SIP.
o We have focused on providing support for HTTP Digest
authentication in SIP, since it is the mandatory authentication
mechanism in SIP. Other documents can extend this one adding
support for other authentication mechanisms if that is required in
the future.
o Added a Security Considerations section.
o The scenario "Diameter server authenticates the user" had an
error, because it was assuming that the MAR/MAA commands were used
to download the user profile. However, MAR/MAA do not contain
provisions to download any user profile. The solution is to add a
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SAR/SAA commands that allow the SIP server to get the user profile
stored in the Diameter server.
o Added the missing Redirect-Host-Usage and Redirect-Max-Cache-Time
to all the answers.
15.6 Changes in draft-ietf-aaa-diameter-sip-app-00.txt from
draft-belinchon-aaa-diameter-mm-app-01.txt
o Application name changed to Diameter SIP application.
o New Definitions section added.
o New Applicability section added.
o The problem of locating a Diameter server is addressed with the
introduction of a new Diameter Subscriber Locator role.
o Added new scenarios to indicate usage in a more generic Internet
environment.
o A few AVPs have been renamed to accurately reflect the intention
of the AVP. For instance, SIP-Server-Name becomes SIP-Server-URI,
and SIP-Public-User-ID becomes SIP-AOR.
o MAR command can be used more generically. Particularly, it does
not assume a SIP REGISTER message. So we had to add a new
SIP-Method AVP to indicate the SIP method that triggered the MAR
command.
o User-Name is no longer mandatory in requests, as typically a SIP
request will not contain a user name. As a result of this change,
a new transit failure Result-Code AVP value has been added:
DIAMETER_USER_NAME_REQUIRED, to indicate the Diameter client that
the request didn't include a User-Name AVP and it is required to
process it. Typically, SIP servers, upon reception of this
Result-Code AVP value, will generate a SIP 401 (Unauthorized) or
SIP 407 (Proxy Authentication Required) to request the user name
from the user.
o IANA section has been carefully rewritten to give detailed
instructions to IANA on what is required to register.
16. References
16.1 Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
Leach, P., Luotonen, A. and L. Stewart, "HTTP
Authentication: Basic and Digest Access Authentication",
RFC 2617, June 1999.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M. and E. Schooler,
Garcia-Martin, et al. Expires June 16, 2005 [Page 66]
Internet-Draft Diameter SIP application December 2004
"SIP: Session Initiation Protocol", RFC 3261, June 2002.
[RFC3310] Niemi, A., Arkko, J. and V. Torvinen, "Hypertext Transfer
Protocol (HTTP) Digest Authentication Using Authentication
and Key Agreement (AKA)", RFC 3310, September 2002.
[RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G. and J.
Arkko, "Diameter Base Protocol", RFC 3588, September 2003.
[ietf-radext-digest-auth]
Sterman, B., Sadolevsky, D., Schwartz, D., Williams, D.
and W. Beck, "RADIUS Extension for Digest Authentication",
December 2004.
16.2 Informational References
[RFC3966] Schulzrinne, H., "The tel URI for Telephone Numbers", RFC
3966, December 2004.
[I-D.ietf-aaa-diameter-mobileip]
Calhoun, P., Johansson, T., Perkins, C. and T. Hiller,
"Diameter Mobile IPv4 Application",
draft-ietf-aaa-diameter-mobileip-20 (work in progress),
August 2004.
[I-D.ietf-aaa-diameter-nasreq]
Calhoun, P., Zorn, G., Spence, D. and D. Mitton, "Diameter
Network Access Server Application",
draft-ietf-aaa-diameter-nasreq-17 (work in progress), July
2004.
[I-D.ietf-aaa-diameter-cc]
Mattila, L., Koskinen, J., Stura, M., Loughney, J. and H.
Hakala, "Diameter Credit-control Application",
draft-ietf-aaa-diameter-cc-06 (work in progress), August
2004.
[3GPP.29.229]
3GPP, "Cx and Dx interfaces based on the Diameter
protocol; Protocol details", 3GPP TS 29.229, September
2004.
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Authors' Addresses
Miguel A. Garcia Martin (editor)
Nokia
P.O. Box 407
NOKIA GROUP, FIN 00045
Finland
Phone: +358 50 480 4586
EMail: miguel.an.garcia@nokia.com
Maria-Carmen Belinchon
Ericsson
Via de los Poblados 13
Madrid 28033
Spain
Phone: +34 91 339 3535
EMail: maria.carmen.belinchon@ericsson.com
Miguel A. Pallares-Lopez
Ericsson
Via de los Poblados 13
Madrid 28033
Spain
Phone: +34 91 339 4222
EMail: miguel-angel.pallares@ericsson.com
Carolina Canales-Valenzuela
Ericsson
Via de los Poblados 13
Madrid 28033
Spain
Phone: +34 91 339 2680
EMail: carolina.canales@ericsson.com
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Kalle Tammi
Nokia
P.O.Box 785
Tampere 33101
Finland
Phone: +358 40 505 8670
EMail: kalle.tammi@nokia.com
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