The Media Application Server (MAS)

When people ask me about MAS, I tell them it's "Sound for the X Window System". Then, I say, "Yeah, network transparent, platform independent sound. You know how you can run your X applications over the network? Well, this gives those applications sound support." If they're still interested, I let 'em have it, "Actually, MAS is completely format-independent. It doesn't care what kind of data it handles, it only knows about sequences of timed events on timestamped data. So you can do video, or any conceivable future time-sensitive data." This is what I've been doing at Shiman Associates Inc. for the past 3 years.

XUDP: A Real-Time Multimedia Networking Protocol - WPI Senior Undergraduate Project

A study of chronological advancements in TCP/IP combines with advanced topics in multimedia communications to produce a functional implementation of a real-time, multimedia internetworking data transmission protocol. This new IP-based protocol, named XUDP, uses the concept of timed-obsolescence and the lessons learned from the development of TCP/IP, yielding an end product that efficiently utilizes the available network bandwidth to transmit real-time multimedia data in a manner that maintains the end user's perception of the linear progression of timed sequential data.

The XUDP Protocol for Timely Multimedia Transport

co-written with David Cyganski

Current efforts to make networked real-time multimedia data distribution a practical reality have focused primarily on the development of means to exploit the TCP protocol. However, much of the Internet is sufficiently slow or congested as to force most multimedia applications to use large ``streaming buffers'' to accommodate the highly non-deterministic nature of this communications channel. Some users may prefer to trade full reliability and corresponding fidelity for a variable quality, but low latency and properly paced transmission.

XUDP (eXtended User Datagram Protocol) is a transport layer protocol that provides an alternative, semi-reliable, method for transmitting real-time, multimedia data over an internet. Through a process of ``timed obsolescence,'' an application can deliberately specify a time to discard any given data parcel for which all comprising UDP datagrams have not been received. This allows placement of a value on the preservation of the timing relationships between sequential multimedia data parcels which is higher than the value given to reliable but un-timely delivery. XUDP is currently implemented as a user-space daemon, operating above UDP through Berkeley sockets, taking advantage of UDP's fast payload checksum and multiplexing ability. It offers full flow-control with a number of TCP-like optimizations and a sockets-like API.

The XUDP Protocol for Timely Multimedia Transport - Presentation

A presentation of the 1997 paper of the same name. Remember, someday the Internet is going to go right to your TV.