STDM - Computer Definition
An improved TDM method that makes use of intelligent muxes, or stat muxes, that can dynamically adapt to the changing nature and associated requirements of the load placed on it in consideration of the available capacity of the circuit. STDM muxes can allocate bandwidth in consideration of the device and application priorities. An STDM can oversubscribe a trunk, supporting aggregate port speeds that can be multiples of the trunk speed, exercising flow control by buffering data during periods of high activity, restraining low-priority transmissions in favor of those of higher priority. STDM muxes may perform data compression, error detection and correction, and reporting of traffic statistics. As shown in Figure S-10, STDMs typically divide a high-speed, four-wire digital circuit into multiple time slots to carry multiple voice conversations or data transmissions. Channelized T1 (North America), for example, commonly provides 24 time slots of 64 kbps. Channelized E-1 (European) commonly provides 30 time slots. Additionally, the individual channels can be grouped to yield higher transmission rates (superrate) for an individual, bandwidth-intensive communication such as a videoconference.The individual channels also can be subdivided into lower-speed (subrate) channels to accommodate many more, less bandwidth-intensive communications, such as low speed data. Also, many muxes allocate bandwidth on a priority basis, providing delay-sensitive traffic, such as real-time voice or video, with top priority. See also buffer, channel, FDM, flow control, oversubscribe, and TDM.