CGRED: class guided random early discarding

A novel active queue management scheme for Internet DiffServ named class-guided random early discarding (CGRED) is proposed in this paper. The key enhancement of CGRED to standard RED is to introduce per-class states at routers and compute probability of discarding packets of different traffic classes adaptively based on the periodical measurements of actually consumed bandwidth of each classes, CGRED can maintain the assigned priority and pre-allocated bandwidth for each service class, eliminate the starvation of lower-priority classes, and ensure that each individual flows of a higher-priority class to obtain averaged rate not less than that of lower classes. Simulation results are presented to show that CGRED is simple, robust and scalable to be implemented.