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Mobile Adhoc Networks (MANETs) are open to a wide range of attacks due to their unique characteristics like dynamic topology, shared medium, absence of infrastructure, and resource constraints. Data packets sent by a source node may reach destination through a number of intermediate nodes. In the absence of security mechanism, it is easy for an intermediate node to intercept or modify the messages, thus attacking the normal operation of MANET. One such attack is Black hole attack, in which, a malicious node called Black hole node attracts all the traffic of the network towards itself, and discards all the packets without forwarding them to the intended recipients. This paper evaluates the performance of Adhoc on-demand Distance Vector (AODV) and its multi-path variant Adhoc On-demand Multi-path Distance Vector (AOMDV) routing protocols under black hole attack. Non-cryptographic solutions Secure Blackhole AODV (SBAODV) and Secure Blackhole AOMDV (SBAOMDV) have been proposed to mitigate the effect of black hole attack. Through NS-2 simulations, the performance of the proposed protocols with video streaming is analyzed. The results show that the proposed solutions provide better performance than the conventional AODV and AOMDV.

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Transmission Control Protocol (TCP) is working well in wired networks. TCP needs modification to work well in wireless networks. This work analyses the performance of the proposed two TCP cross layer flavours, namely the TCP-AL and TCP-WPAL. The cross layer interaction (TCP-WPAL) produces better performance than the TCP-AL. The PDR (Packet Delivery Ratio) of the TCP-WPAL is increased, and the delay and jitter of the TCP-WPAL are decreased in multihop wireless networks. Keywords: TCP, Wireless networks, TCP-AL and TCP-WPAL