A review of flow conflicts and solutions in software defined networks (SDN)

Abstract

Software Defined Networks (SDN) are a modern networking technology introduced to simplify network management via the separation of the data and control planes. Characteristically, flow entries are propagated between the control plane layer and application or data plane layers respectively while following flow table instructions through an OpenFlow protocol. More often than not, conflicts in flows occur as a result of traffic load and priority of instructions in the data plane. Several research works have been conducted on flow conflicts in SDN to reduce their adverse effect. Solutions to flow conflict in SDN have three main limitations. First, the OpenFlow table may still cause a defect in the security module according to the priority and action matching in the OpenFlow of the control plane. Second, flow conflict detection requires more time due to flow tracking and incremental update, whereas in such a case, delay affects the efficiency of SDN. Besides, the SDN algorithm and mechanism have substantially high memory requirement for instruction and proper functioning. Third, most of the available algorithms and detection methods used to avoid flow conflicts have not fully covered the security model policy. This study reviews these limitations and suggest solutions for future research directions.