Abstract: A telecommunications system uses an external application gateway (EAG) in communication with a network call control element and external server systems for controlling calls. The telecommunications system further includes a session initiation protocol (SIP) proxy, an intelligent application proxy, and an intelligent application call control. The EAG communicates with a network call control element of a packet network and a third party application server for controlling calls. The external application gateway controls the flow of information between the network call control element and the third party application server, performing such functions as modifying or stripping out network-proprietary information with delivery of the modified messages to the third party application server, keeping track of call state information and associating messages with specific calls, verifying that the third party application server is making only allowed requests, and limiting traffic volumes.

Abstract: Telecommunications systems for providing third party service support and call control in using a packet network are disclosed. The telecommunications systems for providing a Session Initiation Protocol (SIP) are based interface for third party service call control and communication connections and support via an external application gateway in communication with a call control element of a packet network. The external application gateway signals a third party application server that controls the call via the SIP interface. The systems include border elements located between the call control elements of the packet network and the media servers of communication systems for providing SIP and media interfaces for the third party media servers or endpoints, which can be located inside or outside of the packet network. The systems include the reuse of existing network architectural elements to provide third party communications support and call control.