Illustrated TCP/IP by Matthew G. Naugle Wiley Computer Publishing, John Wiley & Sons, Inc. ISBN: 0471196568   Pub Date: 11/01/98

Chapter 207
Mixers

Mixers perform a vital service. Mixers do not intake a source stream and translate it to another type of stream. Mixers combine multiple source streams into one single stream and preserve the original format. For example, if you were having a audio conference between four network stations, and another network station over a low-speed link would like to join, the mixer would simply pull the three network stations into one single stream instead of three for communication to the network station over the low-speed link. As shown in the slide, a digital audio conversation is being carried on between four workstations, each consuming 64 kbps for their own personal use. When the fifth network station wants to join the conversation, but its link is only 64 kbps, the mixer combines all four higher-speed audio signals into one 64 kbps stream. This allows the network station over the low-speed link to join the conversation and the other network stations maintain their high-speed and probably high-quality audio links.

Basically, mixers and translators allow for variances to occur in an multimedia stream. Whether it is translating streams from one format to another, or allowing for the mixing of signals to accommodate for differences, these two types of devices are very much a part of the RTP protocol.

Mixers