VoIP Over the Internet: Is Toll Quality Achievable?

Wednesday, May 12th, 2004 at 6:00 PM

TI Auditorium


Speaker: Dr. Mansour Karam

Bio: Mansour Karam (M 98)received the B. Engineering degree in Computer and Communications Engineering from the American University of Beirut, Beirut, Lebanon, in 1995 and the M.S. and Ph.D.degrees in Electrical Engineering from Stanford University in 1997 and 2001, respectively. He is currently a Technical Lead at RouteScience Technologies. His research interests include the support of multimedia applications in wired and wireless networks and routing control over the Internet.

Mansour Karam is a member of the IEEE, and has co-authored the paper "Assessment of Voice over IP in Internet backbones", which was selected among the best 10 papers of Infocom 2002.

Title: VoIP Over the Internet: Is Toll Quality Achievable?

Abstract: A main obstacle to the migration of voice communications from the public switched telephone network (PSTN) to voice-over-IP technology on the Internet has been a well-founded concern about the resulting degradation in call quality and reliability.
VoIP has been demonstrated to work effectively on private IP networks where link quality is consistently high and where other IP traffic is tightly regulated. The public Internet, however, was originally architected for best effort data communications, and is comprised of many different regional networks with varying link quality and completely unpredictable traffic flow.
With the current move toward data/voice convergence, the expectations for IP infrastructure in terms of network reliability, as well as application quality and availability, have increased drastically. Despite constant progress in these areas, the observed overall availability of typical Internet infrastructure rarely exceeds 99.9 percent, or three nines. This is significantly short of the 99.999 percent five nines expectation that is customary in traditional circuit switched voice communications. Recent technological advances can close this availability gap through an intelligent use of infrastructure monitoring, real-time call quality assessment and adaptive control that leverages the inherent redundancy in most networks. This article will first present an overview of these technological advances, and will then go over case studies which demonstrate that toll quality voice communications is possible over the Internet, given the appropriate amount of network redundancy and adaptive control technology that is capable of taking advantage of this redundancy.