H-SOFT: a heuristic storage space optimisation algorithm for flow table of OpenFlow

摘要

OpenFlow has become the key standard and technology for software defined networking, which has been widelyrnadopted in various environments. However, the global deployment of OpenFlow encountered several issues, suchrnas the increasing number of fields and complex structure of flow entries, making the size of flowtable inOpenFlowrnswitches explosively grows, which results in hardware implementation difficulty. To this end, this paper presentsrnthe modelling on the minimisation for storage space of flow table and proposes a Heuristic Storage space Optimisationrnalgorithm for Flow Table (H-SOFT) to solve this optimisation problem. The H-SOFT algorithm degradesrnthe complex and high-dimensional fields of a flow table intomultiple flow tables with simple and low-dimensionalrnfields based on the coexistence and conflict relationships among fields to release the unused storage space due tornblank fields. Extensive simulation experiments demonstrate that the H-SOFT algorithm can effectively reduce thernstorage space of flow table. In particular, with frequent updates on flow entries, the storage space compression raternof flow table is stable and can achieve at ～70%. Moreover, in comparison with the optimal solution, the H-SOFTrnalgorithm can achieve the similar compression rate with much lower execution time.