摘要 |
A method of controlling subscriber access to SIP-based services facilitated by an IP Multimedia Subsystem. The method comprises defining at a Serving Call Session Control Function node at least one default screening trigger, and downloading from a Home Subscriber Subsystem, specific screening triggers allocated to at least certain subscribers. At the Serving Call Session Control Function node, at least certain SIP messages originating at subscriber terminals are intercepted and, for each intercepted message and in the absence of a matching specific screening trigger, the default trigger is activated so as to cause the SIP message to be forwarded to a specific SIP application service.
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