Govindarajan J. currently serves as Assistant Professor at Department of Computer Science and Engineering, School of Engineering, Coimbatore Campus. His areas of research include Computer Networking and Software Engineering.






Publication Type: Journal Article
Year of Publication Publication Type Title
2016 Journal Article J. Govindarajan and Kousalya, G., “A Novel Flow Regulation Protocol to Optimize the End-to-End Performance and Fairness Over LEO Satellite Network”, Arabian Journal for Science and Engineering, vol. 41, pp. 3239-3253, 2016.[Abstract]

The major challenge in the utilization of satellite network for the Internet access is its differing nature with wired network. To increase the performance of TCP-based applications over satellite network, performance enhancement proxies (PEP) had been incorporated. However, the existing PEP solutions have violated the end-to-end semantics of Internet applications. To solve this problem and to meet the future needs of the communication network, next-generation transport architecture (Iyengar and Ford in flow splitting with fate sharing in a next-generation transport services architecture, 2009; in A next-generation transport services architecture, 2009. has been proposed. In this architecture, flow regulation functions (flow regulation layer) are factored out from end-to-end best delivery (endpoint layer). As a contribution to this research direction, we propose a novel flow regulation protocol to control the flows in terms of congestion, error and fairness over the Low Earth Orbit satellite environment. Simulation results reveal that the proposed protocol can provide optimized end-to-end performance (high throughput, high goodput and high information efficiency) without violating end-to-end semantics, and it also meets the network-level objective of fairness among the flows. More »»
2015 Journal Article J. Govindarajan, “An enhanced cross layer selfish node detection scheme to avoid false negative case in MANET”, International Journal of Applied Engineering Research, vol. 10, pp. 6151-6162, 2015.[Abstract]

Cooperation between the nodes is the main idea behind the MANET design. The presence of partial cooperative and non-cooperative nodes inside the network significantly reduces the performance of other nodes inside the network. Cross layer misbehavior detection is an approach to improve the detection efficiency with help of MAC and Network layer information. However, the existing detection schemes have not addressed the false negative case. The main aim of this work is to propose a modification to avoid false negative case in cross layer based misbehavior detection. © Research India Publications.

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2015 Journal Article J. Govindarajan, Vibhurani, N., and Kousalya, G., “An analysis on TCP packet reordering problem in Mobile Ad-hoc Network”, Indian Journal of Science and Technology, vol. 8, 2015.[Abstract]

In Ad-hoc network, Packet reorder is effect of many causes like congestion loss, packet loss due to corruption, multi-path routing and node's mobility. Transmission Control Protocol (TCP) performs poorly over wireless links which misinterprets the reordered packets as lost packets due to congestion. This has motivated researchers on developing TCP variants towards packet reordering problem for enhancing TCP performance. Some researchers have found the opportunity to use existing TCP variants like SACK, TCP-Westwood to address the reordering problem. TCP-DCR (TCP-Delayed Congestion Response) and RR-TCP (Reordering Robust TCP) are the TCP variants to acknowledge the packet reordering at the end level. In the existing investigations, the protocols were tested in a simulation environment with one or two causes (congestion or error) at a time over a simple topology. In our experiments, the simulation study of TCP variants has been done with all reordering causes simultaneously, over a large ad-hoc environment including mobility and multi-path routing. A performance analysis had been done using reordering metric (percentage of reordering) which accounts for earlier and lately arriving reordered packets and estimated using throughput and goodput metrics. From our analysis, it is observed that the Selective acknowledgement option of SACK-TCP and the delayed congestion response of DCR help to achieve better performance than other variants in presence of low reordering due to high congestion and low error. However, these variants were failed to meet up their performance in case of high reordering (reordering greater than 50%) due to high congestion loss and high channel error losses. This observation has given the research opportunity to incorporate a discrimination algorithm in the existing reordering solutions to classify the packet error from packet reordering.

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2015 Journal Article J. Govindarajan, Devi, G. Aa, and Kousalya, Gb, “Analysis of TCP-unfairness from MAC layer perspective in wireless Ad-hoc networks”, Indian Journal of Science and Technology, vol. 8, 2015.[Abstract]

In Ad-hoc networks every single node or station takes the responsibility to forward the data packets from the nodes that lie in the range with them. This additional routing responsibility might lead to performance degradation in some cases. Moreover, it is also reported that TCP which is designed for wired networks exhibit poor performance in terms of throughput and fairness in ad-hoc networks. Attempts to alleviate this issue included solutions from both TCP and MAC layer protocol modifications. This work aims at in-depth analysis of MAC level solutions (basic 802.11, 802.11 with RTS/CTS and Collision Detection Mechanism Based-MAC) to address TCP unfairness problem in 802.11-based multi-hop networks. A set of simulation based experiments are conducted and their observations are analyzed using metrics like throughput, goodput and loss probability. The metric loss probability is taken to investigate the protocols both from the perspective of congestion and collision i.e. the impact of congestion window and contention procedure on the end-to-end performance. The results obtained from the simulation revealed the inefficiency of the CDMB-MAC in the scenarios where hidden and exposed terminals do not exist. Further when TCP congestion window is set to 1 the basic 802.11 MAC is found sufficient to provide higher throughput with better fairness among the TCP connections but when TCP congestion window size is increased to 32 the 802.11 MAC with RTS/CTS scheme gives better performance. Added to this all the three MAC protocols fail in the scenario where the source and destination of a connection lie in the transmission ranges of destination and source of other connections. Therefore it can be concluded that it is indispensable to design an adaptive MAC protocol that could provide Fairness among TCP connections in all scenarios.

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2013 Journal Article R. Gomathi, J. Govindarajan, and Jose, S., “A Survey on Detection Schemes of Misbehaving Nodes in MANETs”, International Journal of Advanced Research in Computer Science and Software Engineering, vol. 3, pp. 1105-1111, 2013.[Abstract]

Mobile Ad hoc Networks (MANETs) are very popular because of their widespread usage. In MANET, each node has to co-operate with each other to perform functions in the network. However some nodes do not participate in routing and forwarding packets which are not destined to them, in order to save their energy. Such misbehaving nodes which try to get benefitted from other nodes but refusing to forward other nodes packets can severely degrade the performance of the whole network. In MANETs, detection of such misbehaving nodes is very important. In this survey, a detailed study of misbehaving nodes, their characteristics and their effects in various layers of the network are discussed. Moreover, various detection schemes which deal with misbehaving nodes are also considered in the discussion. This paper discusses the different schemes for misbehaving node detection in MANETs. More »»
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