CECT: Computationally Efficient Congestion-avoidance and Traffic Engineering in Software-defined Cloud Data Centers

The proliferation of cloud data center applications and network functionvirtualization (NFV) boosts dynamic and QoS dependent traffic into the datacenters network. Currently, lots of network routing protocols are requirementagnostic, while other QoS-aware protocols are computationally complex andinefficient for small flows. In this paper, a computationally efficientcongestion avoidance scheme, called CECT, for software-defined cloud datacenters is proposed. The proposed algorithm, CECT, not only minimizes networkcongestion but also reallocates the resources based on the flow requirements.To this end, we use a routing architecture to reconfigure the network resourcestriggered by two events: 1) the elapsing of a predefined time interval, or, 2)the occurrence of congestion. Moreover, a forwarding table entries compressiontechnique is used to reduce the computational complexity of CECT. In this way,we mathematically formulate an optimization problem and define a geneticalgorithm to solve the proposed optimization problem. We test the proposedalgorithm on real-world network traffic. Our results show that CECT iscomputationally fast and the solution is feasible in all cases. In order toevaluate our algorithm in term of throughput, CECT is compared with ECMP (wherethe shortest path algorithm is used as the cost function). Simulation resultsconfirm that the throughput obtained by running CECT is improved up to 3xcompared to ECMP while packet loss is decreased up to 2x