OpenISMA: An Approach of Achieving a Scalable OpenFlow Network by Identifiers Separating and Mapping

Scalability is always a serious issue influencing the development of Software-Defined Network (SDN). Identifiers Separating and Mapping Architecture (ISMA) is a promising solution to the current Internet scaling problems by dividing the network into edge network and core network. In this paper, we adopt the idea of identity and locator splitting with SDN to aggregate flow table entries in the core network switches. Particularly we propose an approach of flow table entries compression in Open Flow network. We define an Open Flow based core forwarding element in core network and propose another coarse-grain forwarding flow table besides the fine-grain flow table to make flow table entries aggregation. Furthermore, we define another Open Flow based access forwarding element connecting the edge network and core network which has a mapping flow table inside. Then we design the prototype including forwarding elements and Open Flow controller with mapping module. Additionally, we compare the performance of our approach with individually applying Open Flow in the Internet, verify the feasibility and flow table entries compression effort using the prototype. The number of forwarding flow table entries in core network can be reduced dramatically.