Abstract

A method and apparatus for computing a congestion indicator in a communications switch including monitoring at least one first congestion indicator in the communication switch, computing an arrival rate and a first and a second service rate, incrementing a second congestion indicator using the arrival rate, and decrementing the second congestion indicator using the first and second service rates. The method and apparatus are used for deciding to store the data and electronic code that arrives at a communications switch when the second congestion indicator is below a first threshold, and for deciding not to store the data and electronic code that arrives at a communications switch when the second congestion indicator equals or exceeds the first threshold. The method and apparatus are also used for controlling the data transfer rates of data sources in an ATM-based network when both available bit rate and other traffic is present in a communications switch. The method and the apparatus utilize intelligent marking to identify data sources with data transfer rates exceeding a marking threshold and direct those data sources to reduce their data transfer rates when the second congestion indicator exceeds a second threshold. When the second congestion indicator exceeds a third threshold or the first congestion indicator exceeds a fourth threshold, the method and apparatus direct all the data sources to reduce their data transfer rates. The marking threshold equals a function of the maximum data transfer rate multiplied by a function of the second congestion indicator.