Link Failure Recovery Mechanism in Software Defined Networks

In traditional networks, the pre-routed packets are dropped during the link failure leading to a huge data loss. Survivability techniques such as protection and restoration are available to provide the solution before and after the link failure. But, the new flow entries that are to be added in the flow table increase the initial network demand leading to an increase in memory demand per switch. The saved data not only reduces the network speed but also demands of repeated processing of entries. In this paper, we propose a new scheme of Group Table based Rerouting (GTR) technique to find the response against single link failure through Fast Fail-over (FF) group table feature provided by OpenFlow. This scheme provides equal roles for both controllers and forwarding OpenFlow enabled switches. Here, the controller maintains a look-up table which is updated periodically according to the change in network structure. Also, it has to update the FF group table simultaneously corresponding to every active port of the switches. The controller relabels the packets and updates the flow entries on respective switches.