Random early detection algorithm using an indicator bit to detect congestion in a computer network

摘要

A switching fabric sets a congestion indicator bit (EFCI bit) in an ATM cell if any queue through which the ATM cell passes is filled above a lower threshold. A Traffic Manager monitors the field of the EFCI bit as cells arrive at an output port of the switching fabric. The traffic manager periodically calculates the ratio of ATM cells having the EFCI congestion bit set to all ATM cells routed to a particular output port. The periodically calculated ratio is used as an input parameter to a Random Early Detection (RED) algorithm. The RED algorithm selects a cell for the switch fabric to drop, by use of a random selection method. The destination computer then does not receive the packet since cells forming part of the packet have been discarded.