An Overlay Architecture for High Quality VoIP

Abstract — The cost savings and novel features associated with Voice over IP (VoIP) are driving its adoption by service providers. Such a transition however can successfully happen only if the quality and reliability offered is comparable to the existing PSTN. Unfortunately, the Internet’s best effort service model provides no inherent quality of service guarantees. Because low latency and jitter is the key requirement for supporting high quality interactive conversations, VoIP applications use UDP to transfer data, thereby subjecting themselves to quality degradations caused by packet loss and network failures. In this paper we describe an architecture to improve the performance of such VoIP applications. Two protocols are used for localized packet loss recovery and rapid rerouting in the event of network failures. The protocols are deployed on the routers of an application-level overlay network and require no changes to the underlying infrastructure. Experimental results indicate that the architecture and protocols can be combined to yield voice quality on par with the PSTN. I