Abstract: The balance between real-time and flexibility is one of the key points for application of SDN technology in power communication networks. Delay calculation of transmission network and data network under traditional architecture as well as the influence of two flow table release mode on control delay under SDN architecture are described in the article. In simulation and test environment, through comparative analysis, hop control strategy and hybrid mode flow table release strategy are proposed based on end-to-end service time delay of power communication. It is concluded that 1) the additional control delay introduced by SDN can be controlled by hop controlling to meet the delay tolerance, 2) the hybrid mode flow table strategy can dynamically balance real-time and flexibility under the premise of satisfying the delay tolerance.

Key words: delay tolerance, software defined networking, flow table release mechanism, reactive mode, proactive mode, hybrid mode