scope:

In multimedia communications, presence, and instant messaging systems, there is a need to define Uniform Resource Identifiers (URIs) that represent services that are associated with a group of users. One example is a resource list service. If a user sends a Session Initiation Protocol (SIP) SUBSCRIBE message to the URI representing the resource list service, the server will obtain the state of the users in the associated group, and provide it to the sender. To facilitate definition of these services, this specification defines two Extensible Markup Language (XML) documents. One document contains service URIs, along with their service definition and a reference to the associated group of users. The second document contains the user lists that are referenced from the first. This list of users can be utilized by other applications and services. Both documents can be created and managed with the XML Configuration Access Protocol (XCAP).