Delay Constrained Communications in a Disaster Site using SDN Framework

In a disaster scenario, it is important to handle the network requests in a delay bound manner such that the rescue teams and survivors can communicate with the outside world effectively and vice versa. This paper addresses the problem of offering multiple service requirements, one having stringent delay but less bandwidth specifications whereas the other type of service can tolerate higher delay. We handle this problem using the SDN framework leveraging its programmability and centralized control. In our solution, each flow is labeled based on the Type of Service field and the controller decides at every switch the link to follow based on the latest delay information. The controller makes use of Dijkstra's algorithm to obtain a path with the shortest delay and alternate paths as well with higher delays. The path also requires to satisfy the minimum bandwidth requirement as specified by a particular flow. Moreover, SDN is able to handle any dynamic scenarios in the network. If there is a link failure or congestion in any path, SDN is able to modify flow rules and make the flow follow alternate paths. Thus, it is able to offer reliable communications in a disaster scenario.