Proposal for supporting variable bit rate services in a TDM circuit-switched network

One of the great challenges for circuit switching systems to be the candidate of the broadband ISDN (Integrated Services Digital Networks) would be the supporting of variable bit rate services. Peak bit rate allocation wastes a lot of bandwidth in case that the traffic is bursty. This paper proposes a novel approach, namely the Dynamic Time-Slot Allocation (DTSA), which provides a way of statistical multiplexing between the variable bit rate sources. The support of DTSA regarding the call admission control and switching are also described. A traffic model for characterizing the behavior of variable bit rate sources is proposed. Performance evaluation is given in terms of the segment loss rate and the statistical multiplexing gain through the analysis based on the proposed traffic model. Unlike the ATM (Asynchronous Transfer Mode), the scheme presented might provide a smooth transition from narrowband ISDN to broadband ISDN.