A new VoIP call admission control scheme with use of alternate routing for low call loss probability

Call admission control (CAC) is essential for the QoS guarantee communications. VoIP services require QoS guarantee in the existing telephony services. This paper proposes a new CAC scheme for VoIP to achieve an efficient use of network resources by adopting a dynamic routing and a routing history table. This scheme chooses the better route out of the two candidate routes where the admission conditions are satisfied. Two candidate routes are randomly chosen from all the available candidate routes. The routing history table memorizes the resulting routing information for the fixed time interval for the succeeding calls. Within the fixed time interval, the succeeding calls are assigned to the same route. After the fixed time interval, the memorized routing information is cleared, and the call admission control algorithm starts again from the beginning. It is confirmed by simulations that the proposed scheme achieves better performance than the existing CAC with alternate routing scheme.