SIP-BASED CALL SESSION SERVER AND MESSAGE-ROUTING METHOD

摘要

A method and SIP-based Call Session Server (50) for routing SIP messages. A Network and Transport layer (53) receives an incoming SIP message and forwards it to one of a plurality of SIP message routing process instances (56a-56n) in a SIP Message Routing Framework (52). The receiving SIP message routing process instance determines a Routing-Key based upon at least one header field in the incoming message, and based upon the Routing-Key, forwards the incoming message to a selected one of a plurality of Back-to-Back User Agent (B2BUA) instances (54a~54n) in a Call Session Control Framework (51). The selected B2BUA instance creates an outgoing SIP message utilizing the Routing-Key to generate a From-Tag in an outgoing request message, or to generate a To-Tag in an outgoing response message, and then forwards the outgoing message to the Network and Transport layer (53), which transmits the outgoing message.