Differentiated Services and Vertical Handovers Supporting Multimedia in Heterogeneous Networks

The popularity of delay and jitter sensitive real-time multimedia applications have raised the need for wireless quality of service (QoS) aware network solutions. Designing heterogeneous wireless systems that support mobility of users is a challenging task because of the diverse QoS of the network systems. The existing QoS mechanisms, such as differentiated services (DiffServ), have been designed for wired networks but the effect on wireless heterogeneous networks is an interesting issue. In this work, we describe an implementation of a DiffServ test network which serves wireless access systems and mobile users. We have measured the impact of DiffServ on one-way delay and jitter of voice over IP (VoIP) traffic. Valuable novelty in our work is gained by measuring the end-to-end QoS using DiffServ during vertical handovers in various system configurations.