Dynamic Selection of Network Protocols for Group Communications in Mobile Ad-hoc Networks

This thesis addresses the topic of dynamically selecting protocols at various levels of network stacks in challenged environments, speci cally those with message loss, long-term fragmentation, and high mobility, in an e ort to meet the demands of group-based messaging applications. Currently, developers select protocols based on a static set of assumptions about the underlying network and application requirements. This thesis introduces a method of sensing the network state, merging this with similar information from peers, and dynamically changing the underlying protocols. This alleviates the need for developers to select protocols and instead assert message requirements. Further, since application instances are involved in group communications, they likely act as such from a mobility perspective, causing di erent portions of the network to have drastically di erent properties. For example, there may be clusters of nodes in certain locations, but minimal connectivity between them. The proposed solution allows systems to adapt to these situations as protocols may be interchanged at any time, allowing the best to be used in any given scenario. The thesis rst establishes a formal de nition of the problem space, and then proposes a solution utilizing Markov Random Fields to classify the network. This classi cation is then used to dynamically select the protocols utilized by the network stack. The Dynamic Protocol Selection Middleware (DPSM) is introduced as the implementation of this approach. Using this middelware, the e ectiveness of the approach is tested in both random group environments and real-world scenarios. In general, DPSM delivered at least as many messages as any statically selected protocol, while delivering substantially more messages in many scenarios with only modest increases in overhead or latency.M.S., Computer Science -- Drexel University, 201