Patent ID: 7929419

Claim:
A method for forwarding or inhibiting message traffic to a terminating session initiation protocol (SIP) server using a SIP server exception list, the method comprising: at an originating Internet Protocol (IP) multimedia subsystem (IMS) call session control function (CSCF): sending status request messages to a plurality of terminating SIP servers to determine their operational statuses, and, in response to failing to receive a response from a terminating SIP server within a timeout period or receiving a response indicating that the terminating SIP server is unavailable, placing the terminating SIP server in an exception list; receiving a request to contact a destination, the request including a domain name; querying a domain name system (DNS) server to resolve the domain name and receiving, from the DNS server, a list of IP addresses corresponding to the domain name and identifying terminating SIP servers; indexing the list of IP addresses received from the DNS server and identifying a first terminating SIP server; determining whether the first terminating SIP server is in the exception list; and in response to determining that the first terminating SIP server is in the exception list, refraining from sending SIP message traffic to the first terminating SIP server, identifying a second terminating SIP server from the list of IP addresses received from the DNS server, determining that the second terminating SIP server is not in the exception list, and sending a request to the second terminating SIP server.