Evaluation and Innovation in Opportunistic Networks

The presence of an increasing number of mobile devices has prompted the demand to use them for information dispersion through opportunistic networks, which they form coincidently due to their geographic location. Opportunistic networks pose several new challenges to the current transmission protocols as they are not only capable of store and forward routing, but also lack the offline routing capability, i.e. source and destination must be connected to the network simultaneously. We can find several opportunistic network protocols in literature, but neither a solid comparison nor a trusted baseline has been presented. In this study, we have analyzed and evaluated eight existing routing algorithms on a common basis in an effort to grasp the strong and weak points of each of them and to see whether it is possible to design a hybrid technique that may take advantage of the strengths of several other techniques. We propose three important criticisms regarding the evaluation of existing routing algorithms. 1. Most evaluations restrict themselves to comparing against the two extremes, direct-contact forwarding and flooding. 2. Each attempt uses a completely different choice of scenario and simulation parameters. 3. Most attempts concentrate on methods to find a path to destination but the reliability of the path cannot be ensured in this paradigm. The findings have revealed that almost all the techniques fail to perform under variable conditions, i.e. bandwidth hungry techniques failed to deliver when bottlenecks existed although, they outclassed every other technique where network had sufficient capacity. In contrast, techniques that required good network connectivity failed to perform in sparse network. As a result of our comparison of selected networks under a wide variety of realistic scenarios, we have not only been able to identify and describe favorable traits of protocols, but also necessary relationships of successful mobile opportunistic network protocols with QoS routing. This study defines a very light weight metric, which not only encapsulates the path bandwidth but also maintains a dynamic path ranking by degrading the path efficiency as it suffers from data load. Moreover, this study focuses on the routing algorithm Nile1 that has an adapting capability with the underlying network. It thereby maintains acceptable performance without exhausting the network resources keeping a check on the network “pulse”, i.e. bandwidth. Nile 1Motivation comes from the notion of controlling floods from the river Nile by constructing dams and barrages across the river banks.