Dynamic Weight Dropping Policy for Improve High-Priority Message Delivery Delay in Vehicular Delay-Tolerant Network

Abstract

Vehicular Delay-Tolerant Network (VDTN) is a special case of Delay-Tolerant Network (DTN) in which connectivity is provided by movement of vehicles with traffic prioritization to meet the requirements of different applications. Due to high node mobility, short contact time, intermittent connectivity, VDTNs use multi-copy routing protocols to increase message delivery rates and reduce the delay. However due to limited resources (bandwidth and storage capacity), these protocols cause the rapid buffer overflow and therefore the degradation of overall network performance. In this paper, we propose a buffer drop policy based on message weight by including traffic prioritization to improve the high priority messages delivery delay. Thus, the memory is subdivided into a high-weight queue and a low-weight queue. When the buffer is overflowing, and a new message arrives, the algorithm determines the message to be dropped in the queues considering that the current node is the destination of the message, the position of the current node with respect to the destination of the message and the age of the messages in the network.

Assessment of the Performance of a Buffer Management System to Improve High Priority Message Delivery Time Limit

“…As mentioned in the previous section, the buffer management strategy proposed in [13] is composed of, on the one hand, the message weight based on local network information, and on the other hand, the combination of the current node's position with respect to the destination and the performance of the PRoPHET routing protocol [14].…”

“…In [13], the weight of a message in the buffer is determined from the following local information: number of jumps, number of copies, size, lifetime, time in buffer and priority class of the message. This weight is given by the following expression:…”

“…In [13], the low weight queue consists of messages that are recent because these messages have low hop counts and low copy counts. In our model, when the current node is an intermediate node and the size of the incoming message is greater than the sum of the high-weight queue size and free space, then we decide to delete all messages from the high-weight queue and then delete the messages from the low-weight queue according to their increasing TTL under a particular condition.…”

“…In [13], the authors proposed a buffer memory management policy based on message weight and the distance between the destination and the intermediate node with high delivery predictability [14]. The message weight is based on local message information.…”

DesCom: Routing Decision using Estimation Time in VDTN

“…chose the alternate route, slow down the speed of the vehicle of change the lane. The paper [19]elaborate buffer management strategy which not only increases delivery rate but also decreases high priority by using the ProPHET routing protocol [20]. According to which, among multiple nearest nodes, the node with maximum delivery probability and situated near to destination is defined as the closest node to the destination due to which delivery rate may be increased.…”