In current telecommunication networks, the value-added services available to subscribers are almost exclusively offered by the carrier providing local telephony service. This results from two factors: the processing for services is either based in or triggered from software executing on the access telecommunication switches, and signaling links over which subscribers request services are terminated on these access switches. In a direct signaling system, the signaling link from a subscriber does not necessarily terminate on an access switch, but rather on an intelligent server we call a call server. The call server invokes service functions and coordinates their interactions. This direct signaling system may be overlaid on various types of access networks, including circuit-switched telephony, packet telephony, wireless local loop, cable, etc. In this paper, we discuss the design, implementation, and performance of a direct signaling system, including procedures that provide varying amounts of integration with current telecommunication systems. Our results show that a direct signaling system using a low-delay direct signaling link and in which no changes are made to existing telecommunication switches incurs approximately 100 ms higher postdial delay than a standard ISDN system. A direct signaling system in which telecommunication switches provide open interfaces and coordinate processing with direct signaling servers incurs approximately 100 ms lower postdial delay than a standard ISDN system.
All Science Journal Classification (ASJC) codes
- Computer Science Applications
- Computer Networks and Communications
- Electrical and Electronic Engineering