Design of Modified RED Implemented in a Class Based CIOQ Switch

A Combined Input and Output Queued (CIOQ) switch with a certain speedup of S (1<S<N) can achieve 100% throughput and offer QoS guarantees. In this paper, we present the deployment of Random Early Detection (RED) on a CIOQ switch that has priority queues with shared buffer (class based switch). We first give an estimated model to concrete that one RED controller per output port is sufficient for a CIOQ switch as long as the speedup is larger than two, and then we extend this conclusion to propose a class based CIOQ switch structure. Furthermore, we modify RED to propose two schemes based on such structure by adaptively setting RED parameters and introduce a dynamic priority queue scheduling scheme. The simulation results prove and demonstrate that our analysis is correct and the proposed algorithms can achieve high utilization and provide delay guarantees.