Buffer Space Tradeoffs for VoIP QoS in Deflection Networks

We consider the issue of QoS (Quality of Service) in a network catering to isochronous VoIP (Voice over IP) sessions. Our simulation experiments strongly suggest that the single–path paradigm of implementing network–layer virtual circuits neither yields the best utilization of network resources (buffer space) nor is it able to provide the best end-to-end service in terms of loss rate and delay. Instead, it turns out that the dynamic exploration of alternative paths at the packet level, i.e., asynchronous deflection routing assisted with small buffer space at the routers, results in a more efficient, and also more economical, delivery. By the latter we mean the lower overall buffer space requirements, aggregated over the routers as well as the end–points of the isochronous sessions.