A Study on the Call Admission and Preemption Control Algorithms for Secure Wireless Ad Hoc Networks Using IPSec Tunneling

In this paper the network architecture under consideration is secure networking, in which an IPSec tunneling encryption device is located at the boundary between the insecure LAN and the secure WAN. This architecture has been used in many DoD tactical networks to satisfy the COMSEC requirements. This makes providing end-to-end QoS support in this type of network very challenging. To address this, a study was launched under the ARMY CERDEC multi-functional on-the-move secure adaptive integrated communications (MOSAIC) program. The salient feature of our solution is that call admission control and preemption control decision is based on the real-time measurements on the traffic loading. We simulated the QoS architecture using OPNET to evaluate the performance characteristics. We studied the performance over five different priority classes for six different applications. The performance metrics under consideration include average delay per priority class for UDP applications, throughput and file transfer completion time for TCP applications, and per class preemption/blocking probability. Our study showed that this integrated solution exhibited superb end-to-end QoS performance over a wide range of traffic loadings