Queueing Analysis for Delay/Disruption Tolerant Networks with Random Link Interruptions
Yanglong Wu, Zexue Li · 2016
In Delay/Disruption Tolerant Networks (DTNs), the Licklider Transmission Protocol (LTP) is proposed to further improve the efficiency of data delivery over links with long delay and frequent interruptions, which operates under the bundle layer running the Bundle Protocol (BP). In this paper, we focus on such kind of BP/LTP based DTN architecture and analyze its performance from the viewpoint of queueing theory. The distinguishing feature of our work is that we take account of random link interruptions in proposed queueing analysis. In DTNs, link interruptions occur inevitably and randomly, having a significant impact on the performance of data delivery. Considering the randomness of link interruptions during bundle delivery, we model the queue at the bundle layer as an M/G/1 queue with random vacations. It should be noted that the service process of the bundle queue is mainly determined by the underlying LTP data delivery mechanism. Firstly, we derive the probability distribution of the bundle service time under random link interruptions. Based on this, the stability condition of the bundle queue is given, which imposes constraints on the bundle arrival process and the link interruption model. Furthermore, we analyze the impact of random link interruptions on the bundle service process and derive the average delay of the bundle queue. Finally, numerical analysis and simulations are conducted to validate our theoretical analysis. We believe that the results of our work are beneficial to optimization and practical deployment of DTNs.