Memory performance optimization of DTN relay node based on M/G/1

摘要

Delay/Disruption Tolerant Networking offers a solution to communications in challenged networks despite the long propagation delay, and intermittent connectivity is commonly characteristic of deep-space communications. It combined with the actual application scenarios of M/G/1 queuing model and based on the data delivery mechanism of store-and-forward and retransmission under Bundle Protocol/Licklider Transmission Protocol in DTN. The data delivery time can be divided into two parts by the last round of LTP data segments transmission process, the custody queue length model of BP data unit (i.e. bundle) in relay nodes memory space is determined by calculating the retransmission time of LTP data segments spent in different delivery parts, which can directly measure the consumption and use of relay nodes memory resources. Without affecting the correct delivery of data and in order to obtain a more perfect memory resources allocation strategy, the optimized length of LTP data segment and the optimized number of bundles aggregated by per LTP block are proposed as the joint optimization scheme. The simulation results show that in deep-space channel environment where bundle arrival rate and bit error rate constantly change, the joint optimization scheme proposed in this paper can always maintain the shortest average queue length, which means, occupy less memory space. Compared with the queue without optimization, the queue length of the joint optimization scheme is reduced by 76.65%, which demonstrates the superior performance of this scheme, and realizes the reasonable optimization and utilization of the memory resources of the relay nodes in DTN.