| Abstract |
A vast expansion of wireless telecommunications technologies has been observed over the last years. A Mobile Ad hoc NETwork (MANET) is an autonomous and dynamic system of mobile hosts that use wireless communication technologies for data transfer. Routing is the process of defining the path of the transmitted data that need to be traversed through a MANET and it is one of the basic network functions. Routing in mobile ad-hoc networks constitutes a basic field of research because the existing routing protocols perform poorly due to the special characteristics of this kind of networks. We will describe the most important suggested protocols and categorize them according to their individual features. The most important amongst them is the Dynamic Source Routing protocol (DSR) is a simple and efficient routing protocol designed specifically for use in multi-hop wireless ad hoc networks of mobile nodes. Using DSR, the network is completely self-organizing and self-configuring, requiring no existing network infrastructure or administration. The use of this protocol has raised many questions concerning its performance. There are several ways for improving the DSR protocols performance; we present and compare the results of using a technique for the management of the routing data stored in the route caches of the nodes by optimizing the cached route lifetime using a Time-To-Live (TTL) interval. Firstly, we study the route lifetime for different length routes in an ad-hoc wireless network. We compare the result with those obtained from a mathematical analysis and conclude that the use of this technique enables the protocol to avoid using routes that lead to time consuming errors. In addition, an algorithm that estimates the lifetime of all routes while the network is active and uses this estimate for routing, was developed. Finally we confirm that the use of the Time-To-Live (TTL) parameter in route caching in a on-demand routing protocol, can significantly improve the networks throughput, decrease the total data transmission delay, and decrease the route caches erroneous information ratio.
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Θέματα Δρομολόγησης σε ad-hoc ΤΗΛΕΠΙΚΟΙΝΩΝΙΑΚΑ δίκτυα
