dc.description.abstract |
A Mobile Ad-hoc Network (MANET) is a collection of mobile nodes where the mobile nodes
are act as router and forming a communications network without pre-existing network
infrastructure and any centralized monitoring. MANET is highly vulnerable to security attacks
so that the performance of congestion control variant of Transmission Control Protocol (TCP)
and routing protocols are affected by the malicious node. TCP assumes that packet drop or loss
is an indication of network congestion, consequently it wrongly retransmits the lost packet and
reduces the packet sending rate, which degrades its performance significantly. In this regard,
an investigation is made into how well these variants and routing protocol respond to different
network conditions particularly with respect to extension of network size and variation of smart
Grey-hole attack. This research aims to analyse four TCP variants (TCP Reno, NewReno,
Vegas and Westwood+) with considering three routing protocol which are Ad-hoc On-demand
Distance Vector (AODV), Ad-hoc On-demand Multipath Distance Vector (AOMDV) and
Destination Sequence Distance Vector (DSDV). Simulation is conducted with lower and higher
node densities and increasing the percentage of malicious smart Grey-hole attack from 0%-
35%. The simulation result reveal that TCP Vegas with AOMDV is the ideal combination of
transport and routing protocol which can adapt fairly well to the changing network size despite
Vegas has a high energy usage especially with AODV routing protocol. However, Vegas has
outperformed other variants with low energy usage in the presence of malicious nodes.
Alongside Vegas with greyholeAODV is the absolute combination of transport and routing
protocols which is less vulnerable for random dropping of packets. On the other hand, the
research affirms the superiority of reactive protocols, over proactive ones with extension of
network size and variation of smart Grey-hole attack. Among the reactive protocols, AOMDV
has been found to be remarkable with extension of network size. Nevertheless, greyholeAODV
outperforms other routing protocols under smart Grey-hole attack. In terms of communication
energy cost, DSDV is the best routing protocol when deploying 0% attack as well us under
10% to 35% of Grey-hole nodes. |
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