Fast Failover Mechanism for SDN-Enabled Data Centers

In this paper, we present mechanisms for fast failover of both the control and data channels in the SDN-enabled data centers. For the data channel recovery, both restoration and protection mechanisms are proposed. The SDN controller computes backup paths based on the complete bipartite graphs of the network topology and configures flow entries of the SDN switches according to both mechanisms, respectively. For the control channel recovery, we assume that the SDN network adopts an in-band control. As a consequence, a restoration mechanism is adopted which re-builds the control path for switches losing the control channel based on a weighting function. We evaluate the proposed mechanisms via a real network as well as the Mininet simulations. Our numerical results show that, for the data channel recovery, the average recovery times for both restoration and protection mechanisms are less than 100ms, and the protection mechanism provides a faster recovery time. We also address the scalability issues, in terms of the size of flow table and the time complexity, of the proposed mechanisms.