Core-Based GRASP for Delay-Constrained Group Communications

Introduction

The recent proliferation of different multimedia real-time applications over the internet —such as Voice-over-IP (VoIP), videoconference, TV over the internet, radio over the internet, multipoint video streaming, distance learning, games, etc.— has created the need for scalable and efficient network support that is capable of providing the level of performance needed for these applications to function properly. The real-time transmission of multimedia information over the internet is characterized by large amount of data that have to be processed and transmitted simultaneously to multiple recipients through underlying computer networks. The transmission must be done under rigorous Quality-of-Service (QoS) constraints in order to ensure that audio and video data are delivered smoothly to the intended recipients. For instance, according to the International Telecommunication Union one-way transmission recommendations (ITU-T Recommendation G.114, 2003), data stream for video/audio conferencing with real-delivery of voice data should be delivered within 400ms. Such delay is acceptable in most situations, though users often start to become dissatisfied if the delay exceeds 200ms. Likewise, latency requirement for first-person shooter games is 100ms (ITU-T Recommendation G.114, 2003). Since most of the multimedia applications are delay-sensitive, the problem of establishing the group communication with minimum cost while satisfying the delay constraints has become one of the most relevant QoS problems.