Research On DSR Protocol With Supporting Real Time Multimedia Transmission And Test-bed Implementation

Among the numerous routing protocols of the wireless Ad hoc networks, the Dynamic Source Routing protocol is very representative. It was proposed by Carnegie Mellon University in 1996. During the development of wireless network, although this routing protocol is improving from time to time, due to the characteristic of DSR, it has the problem of expensive control overhead and the mechanism of judging link failure does not work well. Furthermore, the DSR routing protocol and other wireless Ad hoc routing protocols ignore the requirements of multimedia traffic transmission. They don't take care of and optimize the transmission of multimedia traffic which has the characteristic of large bandwidth, low delay, tolerance of low packet loss ratio. With the technology improvement in wireless network, more and more applications and business require multimedia support, so how to extend the wireless routing protocol to support multimedia traffic is out topic of this paper. In this paper, due to the low efficient and unreasonable architecture of DSR test-bed program, we firstly rebuild the whole architecture of DSR test-bed program according to architecture of AODV test-bed program. Secondly, we extend the DSR routing protocol, add the QoS support and admission control mechanism. For each new multimedia traffic in Ad hoc wireless network, the admission control mechanism judges weather the QoS parameters such as bandwidth, delay meet the new multimedia traffic requirements. If so, the new traffic is allowed to enter the network.At last, in order to solve the large delay of route discovery in real Ad hoc network which could greatly degrade the quality of multimedia traffic, we proposed backup route mechanism. During the traffic transmission using the primary route, we maintain a backup route. When the primary route breaks down, this mechanism guarantee traffic will switch to the backup route with no delay which avoid delay of re-finding route.At last, in order to test the extension and improvement of original DSR, we have done a series of experiments outdoors. According to analyzed experimental data and compared with original DSR routing protocol, the new DSR routing protocol has great improvements in packets delivery ratio, the times of route failure, admission control. It could guarantee the transmission of multimedia traffic when each node in Ad hoc wireless network is moving less than or equal than the walking speed. In a word, the success of the experiments shows that after our improvement and extension to the original DSR protocol it has been able to support the real-time multimedia traffic's transfer very well and been getting more useful in our daily life.