Title: Reliable, Scalable and Interoperable Internet Telephony
Speaker: Dr. Kundan Singh
Date: November 27, 2008
Abstract:
The public switched telephone network (PSTN) provides ubiquitous availability and very high scalability of more than a million busy hour call attempts per switch. If large carriers are to adopt Internet telephony, then Internet telephony servers should offer at least similar quantifiable guarantees. I present a reliable, scalable and interoperable Internet telephony architecture for user registration, call routing, conferencing and unified messaging using commodity hardware.
The results extend beyond Internet telephony to encompass multimedia communication in general. The architecture deals with two aspects: at least PSTN-grade reliability and scalability of the Internet telephony servers, and interoperable Internet telephony services such as conferencing and voice mail using existing protocols. I describe Columbia InterNet Extensible Multimedia Architecture (CINEMA) that consists of a registration and proxy server, a multi-party conferencing server, an interactive voice response system and a multimedia mail server. CINEMA facilitates collaboration using synchronous communications like multimedia conferencing, instant messaging, shared web-browsing, asynchronous communications like discussion forum, shared files, voice and video mails, and seamless integration with telephone, IP phone, web and electronic mail.
I present two techniques for providing scalability and reliability in the Session Initiation Protocol (SIP): server redundancy and a novel peer-to-peer architecture. For the former, I use DNS-based load sharing among multiple distributed servers that use backend SQL databases to maintain user records. The two-stage architecture scales linearly with the number of servers. For the latter, I describe a peer-to-peer Internet telephony architecture that supports basic user registration and call setup as well as advanced services such as offline message delivery, voice mail and multi-party conferencing using SIP. It interworks with server-based SIP infrastructures.
Finally, I present some of the scalability, robustness and performance challenges in an Internet-wide web-based video telephony platform.
About the Speaker:
Dr. Kundan Singh did his Ph.D. in networking from columbia university in 2006. More information about his work can be found at: http://www.cs.columbia.edu/~kns10/publication/.