Phase 2: Token Ring
CIBER then moved to a 16 Mbps token ring. With its higher data rate and more efficient access-control technique, token ring seemed poised to handle the load. With the museum's opening date approaching, CIBER went ahead with an installation that involved the token ring LAN, dual servers, and Macintosh Quadra 840 workstations. After about a month of installation and shakedown, CIBER was ready for a "dress rehearsal" demonstration. Much to everyone's dismay, the new configuration also dropped packets. Full-motion video consists of 30 frames per second, and the system dropped about half of these frames. With the audio, the delivery was so choppy that the workstations would fill up a local cache until it was full, play part of the tune, and then have to wait for more data to arrive.
With less than three months until opening, CIBER needed to go into high gear. An analysis of the working configuration indicated both raw performance problems as well as problems in the way that the communications software and protocols were handling requests. For example, at the server end, the software was chopping the audio and video streams into very small packets, and the Macintosh workstations were unable to reassemble them fast enough to provide real-time audio and video.