Abstract
Multimedia applications have been the key driving force in converging fixed, mobile and IP networks. A major hurdle in the realisation of this convergence is obtaining Quality of Service from a heterogeneous, best-effort service network. Interactive voice requires strict bounds on delay, jitter and packet losses, for Different Network Traffic Intensity, whereas video adds significant bandwidth requirements to the network, while Internet only makes its best effort to deliver a packet. Hence, the end-to-end QoS management of heterogeneous networks supporting multimedia services is of paramount importance. We present an empirical performance study of multimedia applications over 802.11 networks within metropolitan area networking environments. Specifically, we study the QoS performance of Voice over IP (VoIP) applications over 802.11-based networks, while sharing the network resources with HTTP and video applications. Using the OPNET simulator, we simulate several realistic application traffic scenarios, and we investigate the performance of VoIP applications by analyzing QoS parameters, such as delay, jitter, MOS, and packet loss ratio. Subsequently, the performance characteristics data of the network, which we obtain through simulations, are used to build a Markov model of the network performance to extend our analysis and gain further insight into the network performance dynamics.