Maximum Concurrent Flow Problem in MPLS-Based Software Defined Networks

Multi-protocol label switching (MPLS) is supported by OpenFlow version 1.2 or higher and widely used in software defined networking (SDN) to achieve higher performance and flexibility. Due to the shortage of the ternary content addressable memory (TCAM), the number of forwarding entries installed in a switch needs to be bounded (node path-degree constraints). Besides, the maximum concurrent flow problem, which asks to maximize the minimum fraction of the flow of a commodity to its demand, is widely studied because of a wide range of applications. In this paper, we address the maximum concurrent flow problem while ensuring the flow routed for a commodity does not exceed its demand (demand constraints) and the node path-degree constraints are imposed, termed the bounded path- degree maximum concurrent flow (BPMCF) problem. We first show the BPMCF problem is NP-hard and intractable to devise any approximation algorithm. Then, we propose an algorithm for the BPMCF problem. Finally, we evaluate the performance of the proposed algorithm through computer simulations and experiments on Global Environment for Network Innovations (GENI) testbed using the real-life traces collected from SNDlib.