Control traffic parameters analysis in various software-defined networking topologies

Software-defined networking (SDN) is one of the most debated topics in the modern IT industry. This networking concept implies that all network control functions are concentrated in a single logical center referred to as the SDN controller. This paper dwells upon the ways to reduce control traffic latency in the OpenFlow-based software-defined network. We have analyzed and classified the main latency types occurring in software-defined networks running the ARP protocol. As a result of our experiments, we have analytically derived an algorithm for processing ARP packets using an OpenDaylight controller. Based on the algorithm, we have derived formulas to calculate the number of OpenFlow control traffic packets. It is shown there is a positive linear dependence between the total control traffic latency, latencies occurring at switches and the controller, and the number of service traffic packets in the network. The paper proposes methods to reduce the total control traffic latency; these methods can be used to optimize software-defined networking in operation so as to comply with approved regulations and recommendations.