TSSBV: A Conflict-Free Flow Rule Management Algorithm in SDN Switches

Software-Defined Network (SDN) radically changes the network architecture in a mobile broadband network by decoupling the network logic from the underlying forwarding devices. The application in 5G systems will face the challenge of detecting conflict policy provided by the SDN controller. Multiple active network functions in 5G systems with the same priority will potentially trigger conflicts among policies with overlapped flow space, causing the flow table explosion. Focusing on the problem that state-of-art flow rule management methods may cause high consumption of ternary content addressable memory (TCAM) during the process of conflict detection and resolution, we propose TSSBV. Our TSSBV algorithm groups the flow entries with the same prefix length together and decreases the redundant bit in vectors. Also, we present techniques for global prioritization of flow rules in SDN switches and provide dynamic priorities for unassisted resolution of these conflicts. We demonstrate the effectiveness and feasibility of TSSBV in a simulated SDN networks through generating synthetic flows that reflect the characteristics of the flows used in real OpenFlow scenarios. Both the emulations and results confirm that TSSBV is more efficient than state-of-art methods in terms of less initialization time and lower conflict search time.