LAP: Link-aware protection for improving performance of loss and delay sensitive applications in wireless LANs

Radio links exhibit highly unpredictable properties such as variable bandwidth and bit error rates that affect the performance of applications in wireless networks. Besides, another critical concern is the protection of applications due to shared and open wireless medium. However, protection services add additional performance overhead to carry out their operations, and incur varying effects on the network performance, depending on link characteristics. Thus, how to provide protected and high performance service is a challenging issue in wireless networks. The problem is even more challenging for real-time applications such as voice over IP (VorIP) with stringent delay and packet loss requirements. In this paper, we present a novel approach to improve application performance by implementing Link Aware Protection (LAP) in wireless local area networks (LANs). LAP exploits dynamic security policy management (DSPM) scheme for adapting protection with varying link quality. We present a real-time implementation of LAP in our wireless LAN test-bed. As a case study, we demonstrate VoIP performance on our LAP enabled wireless clients. The results show the possibility of maintaining an adequate protection and achieving improved performance for VoIP streams under link variations.