Combining narrowband applications with broadband transport

摘要

ATM is used as a transport and switching mechanism in a hybrid STM/ATM network (20), while the signaling remains normal narrowband signaling. The narrowband signaling is transported on permanent paths over ATM connections, and the narrowband speech channels are transported on ATM and switched on a "per call basis" (on-demand) through an ATM switch. The hybrid STM/ATM network has an access node (22) which services narrowband terminals and which generates a signaling message in connection with call setup. A translator (50) formats the first signaling message into ATM cells so that the first signaling message can be routed through an ATM switch (40) to a circuit switched (STM) node (30). The circuit switched node (PSTN/ISDN) sets up a physical connection for the call and generates a further signaling message for the call, the further signaling message pertaining to the physical connection. The ATM switch routes an ATM cell-formatted version of the further signaling message to another ATM switch over an ATM physical interface (41). Thus, the ATM switch switches both narrow band traffic and signaling for the call over the ATM physical interface.