In this paper, we present a scalable algorithm, capable of finding a single-path traffic-engineered solution for routing traffic in a Differentiated Services network by means of explicit paths. Additional supported features are preemption, fast restoration, with a choice of protection scheme, oversubscription and resource class affinity. The performance of the algorithm is demonstrated by means of statistical simulations on randomly generated network topologies.

We develop a methodology to set the VoIP application parameters (voice packet size and dejittering delay) and the UMTS air interface parameters in such a way that the quality of VoIP calls involving a UMTS party is ensured. We use analytical techniques to determine the delay and packet loss contributions of the various transmission stages crossed by the voice packet flow, and the E-model to predict the perceived quality. Our numerical results show that provided the parameters of the VoIP application and the UMTS air interface are chosen properly, UMTS access and the stringent delay and packet loss requirements of VoIP are reconcilable.