Application of Modified ACO Meta heuristic in Spray and Wait Routing

Routing decision plays a vital role in delivering a message to its destination in a network, especially in an opportunistic network where connectivity between nodes is unpredictable i.e. intermittent connectivity; routing decision dominates in measuring the network performance parameters. Delay Tolerant Networking (DTN) was proposed to address the technical communication problems in heterogeneous networking ranging from extreme terrestrial environments to planned networks in space. Designing a routing policy for such a network should ideally feature proper handling of the implementation risk and must increase the delivery ratio maintaining a cost of minimum overhead. This paper elucidates a new routing policy based on Swarm intelligence specifically Ant colony optimization technique. An existing routing algorithm in DTN called Spray and Wait (SnW) Routing has been modified by changing the spray phase where the ant colony algorithm will make decisions about the number of copies to be sprayed at each relay node. Proposed method gives much more effective results when compared to existing spray and wait mechanism and Ant colony based protocol in DTN. Spray and wait mechanism lags behind in terms of overhead ratio while the latter lingers with regard to both; delivery ratio as well as overhead ratio. The results obtained through simulations open the gates of great opportunities for the successful implementation and desired performance of the proposed algorithm in real life scenarios as well.