Communication system architecture and operating methods thereof

To ensure an effective mechanism for disaster recovery, system migration and network enlargement, a communication system (FIG. ) comprises a narrowband-to-broadband interface having a plurality of network adaptors (-) interconnected to a switch (-) that provides access to a plurality of virtual channels (-) supported by a broadband network. The plurality of network adaptors (-) are also coupled to a plurality of trunks (-) that each support at least one of a plurality of different communication functions. At least two call servers (-) are independently coupled to the narrowband-to-broadband interface and are arranged to control interconnection of trunks to virtual channels, while each of the at least two call servers is responsible for controlling interconnections of group of trunks that share a common communication function within each group. Communication system functionality is therefore separated between the at least two call servers.