In another embodiment, call control may be split or partitioned between the carrier and enterprise networks as depicted in the network configuration 200 of FIG. 2. In this implementation, an enterprise gateway server (GS-E) 182 interacts with a carrier gateway server (GS-C) 180 deployed in the carrier network. The connection between GS-E 182 and GS-C 180 may be made over SIP or other protocols. This configuration may enable cellular network system 110 to have a central point of control for interacting with multiple enterprises, and may not require the use of SS7 messaging to the enterprise. Rather, it is possible to have a secure IP connection supporting SIP. This is also useful for offering a Centrex solution for interconnecting with a carrier-hosted PBX, or for interconnecting a carrier-hosted gateway server with enterprise-hosted PBX 158 systems. GS-C 180 may support an SS7 point code multiplexer in which only one or two point codes are needed to address all enterprises since GS-C 180 can identify for which enterprise the message is intended. In the illustrative example, GS-C 180 has a point code “Point CodeA” and softswitch media gateway 181 has a point code “Point CodeB”. GS-E 182 may be adapted to provision GS-C 180 automatically over the IP interface to manage subscribers, e.g., to add new pilot directory numbers (DNs) for new subscribers. In this case, originating and terminating triggers used in cellular network system 110 for routing calls to GS-C 180 can add identifying information of the specific enterprise in the triggering messages. Alternatively, GS-C 180 may identify the enterprise based on the calling party information.
