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Chapter 18 - Service Configuration in the IMS

Chapter 17 provided a description of the protocols at the user’s disposal for configuring services on the Internet. We saw that the service configuration architecture assumes an XML document stored on a server. The client retrieves a copy of the XML document, makes changes to it, and sends the delta back to the server. In IMS, the architecture for service configuration architecture is developed around the XML Document Management (XDM) architecture created by the Open Mobile Alliance (OMA) in the XDM [244] set of specifications. . | Chapter 18 Service Configuration in the IMS Chapter 17 provided a description of the protocols at the user s disposal for configuring services on the Internet. We saw that the service configuration architecture assumes an XML document stored on a server. The client retrieves a copy of the XML document makes changes to it and sends the delta back to the server. In IMS the architecture for service configuration architecture is developed around the XML Document Management XDM architecture created by the Open Mobile Alliance OMA in the XDM 244 set of specifications. XDM allows a user to modify XML documents stored in remote network servers. It also allows the local copy of those XML documents in the IMS terminal to be synchronized with the copy stored in network servers so that if the user makes changes to one XML document from a given IMS terminal other terminals are updated with the latest changes. Last the XDM architecture also provides limited support for searches of information stored in these XML documents. 18.1 XDM architecture Let us describe the XDM architecture with the help of Figure 18.1. The XDM architecture assumes a terminal that implements the role of an XCAP client and one or more servers called XDM servers that implement the role of XCAP servers. XML documents are stored in any of the servers and kept synchronized with the copy in the client. When a user wants to change a configuration setting in a service such as adding a friend to a presence list the user changes the local copy of the XML document in the client and sends the change to the server which applies it and stores an updated version of the XML configuration document. The XDM architecture introduces the following concepts. XDM client XDMC . This is an XCAP client running in the IMS terminal. The XDMC implements the core XDM features and some application-specific features. Aggregation proxy. This is an HTTP proxy that is configured as an HTTP reverse proxy. The Aggregation Proxy authenticates