Analysis of Different Buffer Management Strategies in Delay Tolerance Network Routing

Abstract

Delay Tolerant Networks or DTNs are the results of the evolutions in the mobile ad hoc networks (MANETs). In such environments the link between the pair of nodes is frequently disrupted due to the dissemination nature, mobility of nodes, and power outages. Because of the environment nature in Delay Tolerant Networks like under water, ocean sensor networks etc., the delays may be very extensive. To obtain data delivery in such challenging and harsh networking environments, researchers have proposed a technique in which the messages is stored into the buffers of intermediary nodes until it is forwarded to the destination. The DTNs are based on the concept of store-carry-and-forward protocols. So, node have to store message for long or short period of time and when connection established replica will be sent to encountered node. A critical challenge is to determine routes through the network without even having an end-to-end connection. This combination of long term storage and message replication imposes a high storage and bandwidth overhead. Thus, efficient scheduling and dropping policies are necessary to decide which messages should be discarded when nodes’ buffers operate close to their capacity. If a relay buffer is full and needs to store a new packet, it has to decide either to keep the current message or to drop it. This paper will give survey on different transmission and dropping policies with their mechanism, their performance in different routing and their limitations.