Characterizing and Estimating Bulk Transfer Size in Mobile Opportunistic Network

In Mobile Opportunistic Networks (MON), messages are transferred in bulk during a contact event. Such bulk transfers may cause a sudden increase in buffer occupancy, which may lead to congestion, and hence impact network performance. Apriori information of bulk transfer size distribution may help in taking proactive measures to prevent the onset of congestion. Therefore, we study the characteristic of bulk transfer size (BTS) and its impact on buffer occupancy. For this, we simulated the network using synthetic and real-life mobility traces and found that the aggregate inter-contact time (ICT) and aggregate BTS can be well approximated by the lognormal distribution. Further, we devised an estimator for mean BTS, which can be used by a receiving node to decide whether to accept or reject the bulk in order to avoid buffer overflow. We also found that an increase in expected ICT leads to an increase in expected BTS, which is confirmed using a simple linear regression model.