Heterogeneous Flow Table Integration for Capacity Enhancement in Software-Defined Networks

Commercial OpenFlow-enabled legacy switches implement flow tables with Ternary Content Addressable Memory (TCAM) to perform high speed flow matching process. However, the size of TCAM-based flow table is restricted to few thousands of entries due to manufacturing cost and high power consumption. In this paper, we propose the Flow Entry Agent which can integrate heterogeneous flow tables, such as ASIC-side MAC/IP/ACL tables and CPU-side SRAM-based tables to increase the storage capacity without modifying ASIC. Besides, the Agent will compress the CPU-side tables and perform flow matching process with these tables. Simulation results show that our Agent can not only increase the capacity of flow table to 11.38x to 65.24x but also reduce 80.99% to 87.36% of Packet_In messages with additional 1 MB CPU-side SRAM.