Virtual-credit: Efficient end-to-end credit based flow control

A new ow control scheme, called virtual credit that may be considered either as a credit based ow-control algorithm without a queue per session at the ports, or as a way to modify the credit based scheme and to bring it closer to an end-to-end rate based scheme, is presented. The new scheme brings the credit based and rate based ow-control schemes closer to each other, giving an attractive compromise between the two schemes. The new scheme enjoys the main advantages of the credit based ow-control scheme while not requiring a queue per session at the switches. A possible disadvantage of the scheme is the large buuer requirement at the switches to ensure very low cell loss rate (but no more than the corresponding buuer requirements in rate based schemes).