| 主权项 |
1. A method for authorizing access by a user device to at least one service offered over an Internet Protocol (IP) network, comprising:
receiving, by a server, a SIP message from the user device, wherein the SIP message includes a Contact header that indicates that the user device is configured to support the at least one service; retrieving from a database, by the server, policy data associated with the user device, said policy data including Dynamic Service Activation Information; validating, by the server, based on the policy data that the user device is authorized to advertise the at least one service and the at least one service is available for access by the user device, when said validating determines that the at least one service is unauthorized or unavailable for access by the user device, modifying, by the server, the received message to generate a modified message, modifying said received message including omitting from said modified message Contact header information corresponding to the at least one service that is unauthorized or unavailable for access by the user device while including information from said received message indicating one or more authorized and available services for the user device; forwarding, by the server, the modified message to a second user device or to a network server; and
when there is a change in a Dynamic Service Activation Information mask value associated with said user device the database sends a message to the server notifying the server of a change in a service authorization state for the user device. |
