Design and analysis of a credit-based controller for congestion control in B-ISDN/ATM networks

A credit-based controller (CBC), which has a provision for cell tagging, is proposed for usage parameter control (UPC). Similar in concept to the leaky bucket, the CBC has a credit counter and a data buffer. Credits are accumulated at a rate initiated from the network (equivalent to the sustainable cell rate), and depleted at a rate pertaining to the network traffic load. A source has the prerogative whether or not to send its cells as tagged cells when the credit level is nonpositive. The queueing behavior of the CBC fed by a Marcov modulated source, is analyzed using a stochastic fluid flow model. It is shown that the performance of the CBC can be altered by tuning the weighting parameter within the CBC. Also, adjustments can be made to balance the ratio of tagged and untagged cells sent into the network.