An algebraic approach for verifying compositions of SDN components

Due to heterogeneity of protocols and time-variation of topology in space information network, Software-Defined Networking (SDN) begins to be used as a novel network architecture. SDN facilitates flexible, scalable and efficient network management, through separating control plane from data plane, thus enabling huge innovation. Network can be easily built, maintained and extended by developing upper SDN applications using API supplied by SDN controller. Similar to general software, modular and componentized development method can increase the reusability of SDN application modules and therefore shorten development period. By composing components already tested or verified, complicated network control functions can be easily constructed. However, it is a problem to ensure the correctness of the network application composed. Verification is a useful means besides testing, but there is a `composition explosion' problem because of plenty of components to compose. This paper proposes an algebraic system, Verification Algebra(VA), for reducing verification transactions when verifying compositions of SDN components. Rules are defined in VA to eliminate configurations or interactions for future verification, based on the existing results of compositions. Multi-tenant network configuration verification is also supported by the algebraic approach proposed in this paper.