QoS in Routing Based on Bandwidth Measurement for Mobile Adhoc Networks

Many applications require guarantees on available bandwidth, small delays and few packet losses. To ensure the constraints, QoS is added to the network. When a node wants to transmit data, it has to consider the bandwidth consumed by the nodes in the transmission range as well as in the carrier sense range. In mobile adhoc networks, measuring the residual bandwidth is a challenging task. Residual bandwidth is estimated by subtracting the consumed bandwidth from channel bandwidth and this new available bandwidth is integrated into the routing process. This paper proposes a QoS based passive technique to measure the remaining bandwidth on the link by considering the bandwidth loss due to the control packets, backoff scheme and collision of packets. Also there is a black hole attack in MANets due to an incorrect reply from an intermediate node. This kind of attack consumes more bandwidth and uses more network resources. The attacker is identified and blocked. It is implemented using enhanced QoS AODV (Adhoc On Demand Distance Vector) routing protocol. This protocol improves performance metrics such as average end-end delay, throughput and packet delivery ratio.