Due to the dynamic nature of a mobile ad-hoc network, it suffers with frequent topology changes. The network topology may change rapidly and unpredictably and the connectivity among the terminals may vary with time. The mobile nodes in the network dynamically establish routing among themselves as they move about; moreover a user in the mobile ad-hoc network may not only operate within the ad-hoc network, but may require access to a public fixed network. Mobile ad-hoc networks therefore should be able to adapt the traffic and propagation conditions as well as the mobility patterns of the mobile network nodes.

Routing is the process of information exchange from one host to the other host in a network. It is an important aspect; an effective routing mechanism is required to establish a smooth transmission across the network. Since the topology of the network is constantly changing, the issue of routing packets between any pair of nodes becomes a challenging task in mobile ad-hoc networks.

Quality of service refers to the ability of a network to provide a more reliable service to selected network traffic. Providing quality of service levels in a constantly changing environment is a challenge. The inherent stochastic nature of communications quality in a mobile ad-hoc network makes it difficult to offer fixed guarantees on the services offered to a device. An adaptive quality of service must therefore be implemented over the traditional resource reservation to support the multimedia services in mobile ad-hoc network.

For most of the light-weight mobile terminals, the communication-related functions should be optimized to save unnecessary power consumption. Wireless ad-hoc networks pose a different challenge for designing power efficient systems. Due to the absence of an infrastructure, each node in an ad-hoc network also acts as a router. For an ad-hoc network to exist, nodes have to be at least in the reception mode most of the time. Ad-hoc networks should be able to balance traffic load among nodes such that power constrained nodes can be put into a sleep mode while traffic is routed through other nodes.

In conclusion, mobile ad-hoc networks have several advantages over traditional wireless networks including ease of deployment, speed of deployment, and decreased dependence on a fixed infrastructure. Mobile ad-hoc networks constitute an emerging wireless networking technology for future mobile communications. In moving forward towards fulfilling this opportunity, the task of finding good solutions for these challenges will play a critical role in achieving the eventual success and potential of mobile ad-hoc network technology.

Eng. Humayun Bakht is pursing 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.