More About This Multicast Project

This multicast is a cooperative endeavor of the North Dakota State University Archaeology Technologies Lab and Archaeological Legacy Institute.

Multicast is a form of Internet media broadcasting that differs in important ways from standard on-demand streaming.  On-demand streaming involves a two-way "conversation" between the end-user's computer and the media file server.  This type of communication requires close real-time coordination between the two ends of the relationship and occupies large amounts of Internet bandwidth as well as lots of computer power (RAM and microprocessor capacity) at the server end.  This could be referred to as "unicasting" because it uses a separate data stream for each member of the audience.   Multicast is a one-way scheduled broadcast of data from the media server to the end-user via an intervening user network node.  Multicasting sends out only one data stream to the routers, which replicate it and send it on to the audience.  It therefore takes much less Internet bandwidth (because end-users do not send data to the media server) and much less computer power for the media server (because no coordination and exchange of data is required with the end-user computers).

Thus, multicast is similar to standard radio and television broadcasting in that the programs are scheduled and sent one way to the user community.  Because the programs are digitally encoded rather than analog (as in radio and most TV), however, the potential quality of the sound and images is very high, depending on the capacity of the system delivering the data and the bandwidth at which the program file is encoded.  The digital format also permits the delivery of multimedia (both moving and still images, sound and text) programming such as is commonplace on The Archaeology Channel.  We have encoded our first program, the Tonto video, at a bandwidth of 1 Mb/sec, which is much higher than standard broadband streaming video, allowing end-users to experience the program full-screen and full-motion (that is, 30 frames/sec) and with video and audio quality comparable to standard TV.  In time, multicast quality could equal or even exceed the standards of HDTV, but this future awaits the creation of a much more robust Internet delivery infrastructure and proliferation of computer hardware with the capacity to take advantage of it.  Our multicast project is an experiment intended to explore the issues associated with, and to prepare for, this development.