Reactive Weight Based Buffer Management Policy for DTN Routing Protocols

摘要

Delay-tolerant networks (DTNs) are distinguished by low connectivity and/or unreliable links, dynamic topology change and network partitioning. Therefore, each node transmits the multiple copies of the message to increase its delivery likelihood. This phenomenon produces congestion that results in the dropping of earlier stored messages. The objective of buffer management policy is to determine which message should be eliminated when the buffer overflow happens. The existing buffer management policies can be divided into two categories: (i) local knowledge-based and (ii) global knowledge based. In a DTN environment, getting global knowledge is impossible and local knowledge-based policies are more practical. This study focuses on the local knowledge-based policies in order to reduce the drop ratio and maximize the delivery. In this paper, we presented a buffer scheduling policy called as weight based drop policy. In this proposed scheme, we dynamically adjust message weight criteria assuming message's properties, which are message size, remaining time-to-live, message stay time in queue, hop count, and replication count. In order to utilize the buffer efficiently we use weight criteria for finding the most appropriate message for drop and rank the forward messages to its neighboring nodes. The simulation performed in ONE simulator. The simulation results of weight based drop policy by using map based mobility movement outperformed the existing DLA, FIFO, MOFO, SHIL and LIFO in terms of reducing a number of transmission, dropped messages, overhead and enhanced delivery and buffer time average.