Emergency and rescue applications must always be available, placing strong demands on middleware solutions running over mobile ad-hoc networks. This highly available distributed event notification service can reach the different network partitions and provide a useful delivery solution. One of the main aims of the ongoing research is to look at different rescue situations that might benefit from mobile devices. These scenarios include equipment delivery, medical diagnosis and treatment, and real-time evidence collections and management.

Among several technical challenges of mobile ad-hoc networks, the sharing of information among various computing devices can be regarded as one of the important issues. Information access and sharing is difficult in mobile ad-hoc networks because of their dynamic nature, scarce resources, and heterogeneous user devices.

A rescue scenario further complicates matters because of requirements llike fault tolerance, survivability, real-time operations, and security. Solving these issues from scratch for every new application based on a mobile ad-hoc network isn't very feasible. A better solution would be to setup middleware services that can support the development of specific applications for the mobile ad-hoc network.

The dynamic nature of a mobile ad-hoc network makes middleware services unsuitable for synchronous communication because they are too vulnerable to communication disruptions. For example, devices might suddenly be out of reach or turned off. The classic alternative to synchronous solutions is a distributed event notification system, shown in Figure A.

FIGURE A

This model illustrates a distributed management system for mobile ad-hoc networks. Click picture for a larger image.

Mobile ad-hoc networks need an effective distributed management solution which can handle various tasks in emergency and rescue operations. This solution should be able to tackle some of the other components of a management system, such as resource management, privacy management and key management.

Resource management in a mobile ad-hoc network is used to track neighboring nodes and their resources to provide information for replication decisions. Privacy management is based on previously gathered certificates, and key management is used for signing and encrypting messages.

Therefore, it's almost crucial to have each of these management issues well addressed at a satisfactorily level, or it's simply not possible to have a powerful distributed management system which can cope with the typical environment of the mobile ad-hoc network.

Dr. Humayun Bakht completed his Ph.D at the School of Computing and Mathematics in Liverpool at John Moores University. Prior to his current course of studies, he has successfully completed his MSc Software Engineering and BSc Electronics Engineering from University of Liverpool UK and Sir Syed University of Engineering and Technology in Karachi, Pakistan. Humayun's research interest is mobile ad-hoc networks, in particular, the development of a new routing algorithm for this type of networking. He can be reached at humayunbakht@yahoo.co.uk and you can visit his Web site at http://www.geocities.com/humayunbakht/.