Performance Optimization of VoIP using an Overlay Network

Voice traffic on the Internet (VoIP) is poised to grow rapidly but the Internet is not engineered for such delay-sensitive applications. We show how the end-user quality of VoIP calls can be improved by rerouting them in an intermediate overlay network and thought the use of various path-diversity and error-coding techniques. We introduce our overlay network (OverPhone) that is tuned to optimize VoIP quality and provide experimental results of its implementation on the PlanetLab testbed. We show that re-routing VoIP calls through OverPhone improves the quality of more than a third of the paths by significant amounts when using the G.711 codec. We believe that this benefit extends to other well known and proprietary codecs as well. We also investigated the benefits and trade-offs of using techniques such as path-diversity and paritycoding. We found that path-diversity is useful in sustaining throughput at high loads, and that parity-codes can be used to trade-off bandwidth for path-quality. 1

[1]  Andreas Terzis,et al.  1-800-OVERLAYS: using overlay networks to improve VoIP quality , 2005, NOSSDAV '05.

[2]  Amin Vahdat,et al.  Detour: informed Internet routing and transport , 1999, IEEE Micro.

[3]  Henning Schulzrinne,et al.  An RTP Payload Format for Generic Forward Error Correction , 1999, RFC.

[4]  Alan Clark,et al.  Modeling the effects of burst packet loss and recency on subjective voice quality , 2001 .

[5]  Robert G. Cole,et al.  Voice over IP performance monitoring , 2001, CCRV.

[6]  Keith W. Ross,et al.  Computer networking - a top-down approach featuring the internet , 2000 .

[7]  Hari Balakrishnan,et al.  Best-path vs. multi-path overlay routing , 2003, IMC '03.

[8]  Rafik A. Goubran,et al.  Speech quality prediction in VoIP using the extended E-model , 2003, GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489).

[9]  Bernd Girod,et al.  Real-time voice communication over the internet using packet path diversity , 2001, MULTIMEDIA '01.

[10]  Henning Schulzrinne,et al.  Integrating packet FEC into adaptive voice playout buffer algorithms on the Internet , 2000, Proceedings IEEE INFOCOM 2000. Conference on Computer Communications. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies (Cat. No.00CH37064).

[11]  Hari Balakrishnan,et al.  Resilient overlay networks , 2001, SOSP.

[12]  Randy H. Katz,et al.  OverQoS: An Overlay Based Architecture for Enhancing Internet QoS , 2004, NSDI.

[13]  Paul E. McKenney,et al.  Packet recovery in high-speed networks using coding and buffer management , 1990, Proceedings. IEEE INFOCOM '90: Ninth Annual Joint Conference of the IEEE Computer and Communications Societies@m_The Multiple Facets of Integration.

[14]  Donald F. Towsley,et al.  Improving VoIP quality through path switching , 2005, Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies..

[15]  Bo Li,et al.  DONet: A Data-Driven Overlay Network For Efficient Live Media Streaming , 2004, INFOCOM 2005.