2009年10月29日

IMS Service and Application (1): XDM




Contacts information distributed on multiple databases and terminals: XDM enabler allowing end-users to manage their contacts lists and user profile information from several applications


- Is a presence-based communication for subscribers to store information such as contact lists, bookmarks, and preferences on the network
- Manage the user request and accesses to the XDM/XCAP database – like XML documents (service data and user profile)
- Store well-structured XML documents in the network where it can be located, accessed and manipulated (retrieved, created, changed, deleted, etc.) via XCAP operations (GET, PUT, DELETE)
- While the users publish information over IMS core, the XDM can not be reached directly for control and security reasons, but updated through requesting the Application Server.

- Introduce a new domain for both fixed and mobile services and applications. And always access up to date information from any clients (fixed or mobile)
- Manipulate of the data is performed via an XDM Client (XDMC)
- Authentication and Routing of XDM Client requesting will be supported for access control
- XDM Client via XCAP may need to connect to a proxy server (as a contact point) which can “aggregate to reach several XDMs” for different applications
- Receive an OMA Directory request or an XCAP Capabilities request, aggregate all the results into one single XML document after broadcast the request to all XDMs with user’s data
- Notify client while any changes subscribed in the stored data
- Support partial updates - only send the notification for the changed information, not the entire XML document.
- Synchronization support for multiple clients/devices manipulating the same document

- Store documents accessed and manipulated in a central repository (as an XCAP Database) via XCAP - XML Configuration Access Protocol, as defined by IETF, has been chosen as the common XML Document Management protocol
- XDM interfaces to IMS Core via SIP
- Levels of roles and permissions based on read/write actions during administration or operation will be required.
- Refer to OMA-AD-XDM-V1_0-20060612-A document, or 3GPP TS 23.511, 23.611

3). XDM Functional Entity:

1. The XDM Client (XDMC) is a client entity that provides access to the various XDMS features
2. The Aggregation Proxy is the single contact point for the XDMC implemented in a UE to access XML documents stored in any XDMS.
- Performs authentication of the XDMC;
- Routes individual XCAP requests to the correct XDMS or to the Cross-Network Proxy;
- Routes individual Search requests to the Search Proxy;
- Optionally performs compression/decompression;
- Support secure data transfer between the Aggregation Proxy and the XDMC, using TLS or other means.
3. The Subscription Proxy is the contact point for the XDMC to subscribe for notification of changes in XML documents stored in any XDMS.
- Performs back-end subscriptions as an RLS as described in [RFC4662], using procedures defined in [IETFXCAP_Diff_Event] for notification of changes in XML documents from a particular XDMS;
- Maps XCAP Resources to SIP addresses of appropriate XDMSs;
- Receives notifications from XDMS, and using RLMI as defined in [RFC4662] aggregates them prior to sending them to the XDMC;
- Sends aggregated notifications to the XDMC.
4. The Search Proxy is a server entity to forward & send search request / response
- Forwards search requests to the XDMS, and to the Cross-Network Proxy when needed;
- Receives responses from the XDMS, and from the Cross-Network Proxy when needed;
- Combines results from the XDMS, and also from the Cross-Network Proxy before sending responses to the XDMC;
- Sends search responses to the XDMC.
5. The Cross-Network Proxy is the single contact point for the XDM enablers located in different networks to communicate over trusted connection.
- Performs authorization of the trusted network;
- Routes individual outgoing XCAP requests to the Cross-Network Proxy of the remote network;
- Routes individual outgoing search requests to the Cross-Network Proxy of the remote network;
- Routes individual incoming XCAP responses to the Aggregation Proxy;
- Routes individual incoming search responses to the Search proxy;
- Optionally performs compression/decompression;
- Support secure data transfer between Cross-Network Proxies using TLS or other means.
6. The Shared List XDMS is a server entity that supports:
- Manages and supports content of URI List and Group Usage List XML documents
- Performs authorization of incoming SIP and XCAP requests;
- Notifies subscribers of changes in XML documents;
- Provides aggregation of notifications of changes to multiple XML documents.
7. The Shared Group XDMS is a server entity that supports:
- Manages and supports content of Group XML documents as described in [XDM_Group];
- Performs authorization of incoming SIP and XCAP requests;
- Notifies subscribers of changes in XML documents;
- Provides aggregation of notifications of changes to multiple XML documents;
- Provides search results.
8. The Shared Profile XDMS is a server entity that supports
- Manages and supports content of User Profile XML documents as described in [XDM_Profile];
- Performs authorization of incoming SIP and XCAP requests;
- Notifies subscribers of changes in XML documents;
- Provides aggregation of notifications of changes to multiple XML documents;
- Provides search results.
9. The Shared Policy XDMS is a server entity that supports
- Manages and supports content of user access policy XML documents
- Performs authorization of incoming SIP and XCAP requests;
- Notifies subscribers of changes in XML documents;
- Provides aggregation of notifications of changes to multiple XML documents.
10. The enabler specific XDMSs are server entities that support
- Performs authorization of incoming SIP and XCAP requests;
- Manages XML documents, which are specific to the service enabler;
- Provides aggregation of notifications of changes to multiple documents stored on the enabler
specific XDMS;
- Notifies subscribers of changes to the enabler specific documents stored in the network;
- Provides search results if applicable.
11. The functionality of the enabler specific Servers are defined in the specifications for the enabler in question.
12. The SIP/IP Core is a network of servers, such as proxies and/or registrars, which perform a variety of services in support of the XDM Service, such as routing, authentication, compression, etc. The specific features offered by different types of SIP/IP Core networks will depend on the particulars of those networks. When the SIP/IP Core is realized using IMS, the OMA XDMSs utilizes the capabilities of IMS as specified in 3GPP [3GPP TS_23.228] and 3GPP2 [3GPP2-X.S0013-002], respectively.
- Routes the SIP signalling between the XDMC, Subscription Proxy and the XDMSs;
- Provides discovery and address resolution services;
- Supports SIP compression;
- Performs a certain type of authorization of the XDMC based on user’s service profile;
- Maintains the registration state;
- Provides charging information.

4). XDM Interface and Protocol Supported:

Interface

Between NEs

Protocol Used

XDM-1

XDMC – SIP/IP Core

SIP

XDM-2

Shared XDMSs – SIP/IP-Core

SIP

XDM-3

XDMC – Aggregation Proxy

XCAP

XDM-4

Aggregation Proxy – Shared XDMSs

XCAP

XDM-5

XDMC – Aggregation Proxy

Limited XQuery over HTTP

XDM-6

Aggregation Proxy – Search Proxy

Limited XQuery over HTTP

XDM-7

Search Proxy – Shared XDMSs

Limited XQuery over HTTP

XDM-8

Aggregation Proxy – Cross-Network Proxy

XCAP

XDM-9

Search Proxy – Cross-Network Proxy

Limited XQuery over HTTP

XDM-10

Subscription Proxy – SIP/IP Core

SIP

IP-1

SIP/IP Core – SIP/IP Core of remote network

SIP

NNI-1

Cross-Network Proxy – Cross-Network Proxy of remote network

XCAP and Limited XQuery over HTTP

“Enabler specific XDMS” – SIP/IP-Core

SIP

Shared XDMSs – “Enabler Specific Server”

XCAP

“Enabler specific XDMS” – “Enabler specific Server”

N/A

“Search Proxy” – “Enabler specific XDMSs”

Limited XQuery over HTTP

“Enabler specific Server” – “Aggregation Proxy”

XCAP

DM-1

DM Client – DM Server

Described in [OMA_DM]

CH-1/-2

Charging Enabler – Charging Enabler Users

Described in [Charging_AD].



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