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

The challeges in implementing security in spontaneous ad hoc networks

Mobile Ad Hoc Networks (MANETS) promise much in the ability to rapidly deploy a wireless network in a fashion where no prior planning is needed and the network can be running efficiently and with high security within minutes. Natural disaster response, military, education and business provide areas where MANETS can offer significant advantages in communication where infrastructure networks may take days to set up or may be impossible to implement. This research reviews a selection of MANET protocols to show the progression of the research and the issues that are yet to be addressed. It discusses the challenges to researchers in improving ad hoc schemes to the point where they work in theory and in practice. Areas are highlighted that pose the most significant challenges to developing new security protocols and some food-for-thought is given for those who wish to contribute to this growing area of importance for wireless communication

Requirement analysis for building practical accident warning systems based on vehicular ad-hoc networks

An Accident Warning System (AWS) is a safety application that provides collision avoidance notifications for next generation vehicles whilst Vehicular Ad-hoc Networks (VANETs) provide the communication functionality to exchange these notifi- cations. Despite much previous research, there is little agreement on the requirements for accident warning systems. In order to build a practical warning system, it is important to ascertain the system requirements, information to be exchanged, and protocols needed for communication between vehicles. This paper presents a practical model of an accident warning system by stipulating the requirements in a realistic manner and thoroughly reviewing previous proposals with a view to identify gaps in this area

A survey of distributed certificate authorities in MANETs

A Certificate Authority (CA) provides the critical authentication and security services for Public Key Infrastructure (PKI) which are used for the Internet and wired networks. In MANETs (wireless and ad hoc) there is an inability to offer a centralized CA to provide these security services. Recent research has looked to facilitate the use of CAs within MANETs through the use of a Distributed Certificate Authority (DCA) for wireless and ad hoc networks. This paper presents a number of different types of DCA protocols and categorizes them into groups based on their factors and specifications. The paper concludes by proposing the best DCA security services in terms of performance and level of security

A fully-distributed, multiagent approach to negotiation in mobile ad-hoc networks

This paper presents an interaction protocol intended to be used in distributed negotiation problems using software agents,\ud which could be applied to multi-agent systems deployed over Personal Digital Assistants (PDAs) connected via wireless\ud networks. We are especially interested in semi-competitive scenarios, where each agent in the system acts on behalf of a\ud user, trying to maximize its user preferences while pursuing a common agreement. In these conditions, and especially if\ud we are dealing with open and dynamic environments like mobile ad-hoc networks, the goals and attitudes of software\ud agents cannot be guaranteed. Taking this into account we propose a protocol where interaction among agents is done in a\ud fully-distributed manner, so that no user can have negotiation privileges over the others