Using NS2 for a new routing method to note the packet drop problem in DTNs

In this paper, we use ns2 to simulate routing methods. Not only compare the delivery ratio but also understand the factors that affect the delivery ratio. We choose four routing methods including our new routing method just been accepted in ICCNT2012 [11], named OOPFE-Routing. We will focus on the packet-drop-problems that don´t depend on buffer queue and don´t consider the network security in delay tolerant networks. From our results, the number of delivery ratio of OOPFE is even better than Epidemic-Routing which is high-bound in theory. The major reason is the overhead of OOPFE lower than Epidemic. Therefore, we discuss about the reasons of overhead. There are three; the first reason is the numbers of repeatedly received packets. The second is the numbers of packets dropped by our setting, when the value of buffer queue is less than 100%. The last is the numbers of packets dropped by other five type reasons in the routing time.