An efficient implementation of storage and lookup for flow tables in OpenFlow

The storage and lookup of OpenFlow flow tables still faces many challenges such as the increasing number of fields in flow inlets, the explosive growth of flow scales, and difficulties in achieving wired-speed processing of ports in OpenFlow switches. To solve these problems, this paper presents an efficient storage and lookup method for flow tables in OpenFlow. This method divides flow tables into multiple sub-flow tables of smaller scale and fewer matching fields. Based on the different types of matching fields, sub-flow tables are split into multiple slices, which can be handled by different algorithms and hardware. The matching result of sub-flow tables can be obtained using the matching results of slices in sub-flow and summary tables. By splitting the flow and sub-flow tables, this method compresses the storage space of the flow table in OpenFlow switches. By optimizing of subflow table selection and lookup processes, this method reduces the cost of hardware resources when executing the lookup process. Extensive simulation experiments show that the proposed method can compress storage space by about 50% and can reduce hardware resource consumption to 80% when executing matching processes.