Call Admission Control (CAC) is an extension to Quality of Service (QoS) for voice traffic over IP and prevents the over subscription of voice traffic. For real-time delay-sensitive traffic such as voice, it is better not to initiate a new voice session rather than to allow voice sessions to be dropped or delayed later, causing intermittent impaired QoS and resulting in customer dissatisfaction. Dynamic routing mechanisms can be integrated with CAC to further extend the capabilities of QoS for VoIP traffic. In dynamic routing mechanisms, probe packets are sent to sense the congestion level of the network and according to the defined threshold, routes are chosen dynamically. CAC is therefore a deterministic and informed decision that is made before a voice call is established to provide suitable QoS for the new call. All of the dynamic routing mechanisms have some issues in selecting random routes. This includes not considering number of hops, not doing admission threshold test, calculating all possible paths. In this research work, authors propose a new dynamic routing scheme, which considers a route history table with endpoint admission control. The main objectives of proposed approach are to increase the call admission probability, make call establishment time faster and save valuable CPU resources. Performance of the proposed scheme with respect to other dynamic routing schemes is studied using a mathematical/analytical model.

Paper presented to the 3rd Annual Symposium on Graduate Research and Scholarly Projects (GRASP) held at the Hughes Metropolitan Complex, Wichita State University, April 27, 2007.Research completed Department of Electrical and Computer Engineering, College of Engineering.