EBMDP: Equal Balance Message Drop Policy for QoS Optimization in Delay Tolerant Networks

Delay-tolerant networks (DTNs) are ad hoc in nature. It is known for characteristics such as intermittent connectivity and dynamic topology. However, a unique characteristic of DTNs is that there is no guarantee of an end-to-end connection between sender and receiver. Therefore, nodes observe long delays in establishing the connection. Once a connection is established between the nodes, the links connecting the nodes are fully utilized, and the buffer memory overflows, resulting in congestion that significantly compromises the quality of services (QoS). To avoid congestion, researchers have developed different buffer management policies. This research presents an efficient buffer management policy, known as the Equal Balance Message Drop Policy (EBMDP), designed to improve QoS in DTN. The EBMDP discourages unnecessary message drop. EBMDP drops selected messages from the overflowed node, and the selection of messages for the drop from the overflowed node is based on the conditions defined by the EBMDP. The results of EBMDP are better than the drop-oldest ap proach (DOA) and size-aware drop (SAD) regarding delivery probability (DP), overhead ratio (OR), buffer time average (BTA), and dropped messages. The delivery probability of EBMDP obtained by simulation is 0.1861, which is higher than the delivery probabilities of SAD and DOA, which are 0.1069 and 0.1114, respectively. Similarly, the overhead ratio of EBMDP is lower than that of SAD and DOA. The results show a significant improvement in the buffer time average, as the buffer time average of messages using EBMDP is greater than that of SAD and DOA. The results also show lower messages dropped (MD) for EBMDP than for MD of SAD and DOA.