Faculty Publications
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Item TCP congestion control in data center networks(Springer New York, 2015) Tahiliani, R.P.; Tahiliani, M.P.; Chandra Sekaran, K.C.Data Center Networks (DCNs) provide the core infrastructure backbone for various small and large scale enterprise applications, including Cloud Computing applications. TCP is used by a plethora of Internet applications today and it also retains its dominance in DCNs, in terms of the most widely deployed transport protocol. The nature of DCN traffic, however, largely differs from that of the Internet. The fundamental assumptions made during the initial design of TCP hinder its suitability in state-of-the-art DCNs. Impairments such as TCP Incast, TCP Outcast, Buffer pressure, Queue build-up and pseudo-congestion effect severely degrade the performance of traditional TCP variants in DCNs. With cloud computing becoming an important part of the forseeable future, it is extremely crucial to eliminate these impairments. First, this chapter describes the above mentioned impairments in brief and explores TCP variants proposed so far to overcome the same. Second, the advantages and shortcomings of each TCP variant are highlighted in terms of its effificacy and the deployment complexity. Open research issues related to the TCP’s performance in DCNs are also discussed. © Springer Science+Business Media New York 2015.Item Anomalous event detection methodologies for surveillance application: An insight(IGI Global, 2017) Rao, T.J.N.; Tahiliani, M.P.; Girish, G.N.; Rajan, J.Automatic visual surveillance systems serve as in-place threat detection devices being able to detect and recognize anomalous activities which otherwise would lead to potentially harmful situations, and alert the concerned authorities to take appropriate counter actions. However, development of an efficient visual surveillance system is quite challenging. Designing an unusual activity detection mechanism which is accurate and real-time is the primary challenge. Review of literature carried out led to the inference that there are some attributes which are essential for a successful unusual event detection mechanism for surveillance application. The desired approach must detect genuine anomalies in real-world scenarios with acceptable accuracy, should adapt to changing environments and, should require less computational time and memory. In this chapter, an attempt has been made to provide an insight into some of the prominent approaches employed by researchers to solve these issues with a hope that it will benefit researchers towards developing a better surveillance system. © 2018 IGI Global. All rights reserved.Item Anomalous event detection methodologies for surveillance application: An insight(IGI Global, 2018) Rao, T.J.N.; Girish, G.N.; Tahiliani, M.P.; Rajan, J.Automatic visual surveillance systems serve as in-place threat detection devices being able to detect and recognize anomalous activities which otherwise would lead to potentially harmful situations, and alert the concerned authorities to take appropriate counter actions. However, development of an efficient visual surveillance system is quite challenging. Designing an unusual activity detection mechanism which is accurate and real-time is the primary challenge. Review of literature carried out led to the inference that there are some attributes which are essential for a successful unusual event detection mechanism for surveillance application. The desired approach must detect genuine anomalies in real-world scenarios with acceptable accuracy, should adapt to changing environments and, should require less computational time and memory. In this chapter, an attempt has been made to provide an insight into some of the prominent approaches employed by researchers to solve these issues with a hope that it will benefit researchers towards developing a better surveillance system. © 2019 by IGI Global.Item Performance evaluation of TCP variants over routing protocols in multi-hop wireless networks(2010) Tahiliani, M.P.; Shet, K.C.; Basavaraju, T.G.Wireless internet has become popular in recent years due to the tremendous growth in the number of mobile computing devices and high demand for continuous network connectivity regardless of physical locations. In this paper, we investigate the effects of routing protocols on the performance of Transmission Control Protocol (TCP) variants in multi-hop wireless networks. Through simulations we study the effects of Destination Sequenced Distance Vector (DSDV), Optimized Link State Routing (OLSR), Ad hoc On demand Distance Vector (AODV) and Dynamic Source Routing (DSR) routing protocols on TCP Tahoe, TCP Reno, TCP Newreno, TCP with Selective Acknowledgment (SACK) option and TCP Vegas. The simulations are carried out for static as well as mobile nodes. The performance metric used is throughput. Another metric, expected throughput is used for the comparison of throughput when nodes are mobile. ©2010 IEEE.Item AMul: Adaptive multicast routing protocol for multi-hop wireless networks(2011) Panwala, V.; Hegde, S.; Tahiliani, M.P.Wireless Networks have evolved as promising technology for numerous applications to provide Internet access to fixed and mobile wireless devices. Multicasting plays a crucial role in many applications of Wireless Networks. Several routing protocols have been proposed for multicast communication in mobile wireless networks. In this paper we propose a reactive and receiver initiated multicast routing protocol called Adaptive Multicast (AMul) to provide better Quality of Service (QoS) in Wireless Networks. Using simulations, we compare AMul with Protocol for Unified Multicasting through Announcements (PUMA) which is also a reactive and receiver initiated multicast routing protocol for Multi- Hop Wireless Networks. Based on the simulation results, we observe that AMul reduces the overall end to end delay while inducing negligible control overhead in the network. © Springer-Verlag 2011.Item Robust two-way locking protocol for key exchange(2011) Shetty, S.; Hegde, S.; Tahiliani, M.P.Sharing of symmetric key between the sender and receiver for encryption and decryption is considered to be one of the major issues in the communication networks. It is due to the fact that the strength of cryptosystem depends not only on the strength of the key, but also on the underlying key exchange protocol. In this paper, we propose a Robust Two-way Locking Protocol which overcomes the drawback of Diffie-Hellman key exchange protocol in terms of flexibility provided to the sender for selecting the desired key. Moreover we demonstrate the applicability of the proposed protocol in TCP handshake and compare it with Secure TCP which is based on Diffie-Hellman (DH) key exchange protocol. Based on the simulation results it is observed that Robust Two-way Locking (RoToLo) Protocol incurs negligible overhead in the network while providing greater flexibility of key selection to the sender as compared to Secure TCP. © Springer-Verlag 2011.Item Ant-CAMP: Ant based congestion adaptive multi-path routing protocol for wireless networks(2011) Raval, C.; Hegde, S.; Tahiliani, M.P.The advent of mobile computing devices and wide deployment of wireless networks have led to an exponential increase in the internet traffic. Long congestion epochs and frequent link failures in wireless network lead to more number of packets being dropped and incur high end-to-end delay, thereby degrading the overall performance of the network. Congestion control, though mainly incorporated at the transport layer, if coupled with the routing protocols, can significantly improve overall performance of the network. In this paper we propose Ant based Congestion Adaptive Multipath (Ant-CAMP) routing protocol that aims to avoid congestion by proactively sending congestion notification to the sender. The proposed Ant-CAMP routing protocol is implemented in Network Simulator-2 (NS-2) and its performance is compared with Ad-hoc On Demand Multi-Path Distance Vector (AOMDV) in terms of Packet Drops due to Congestion, Packet Delivery Fraction and Average End-to-End Delay. © Springer-Verlag 2011.Item TCP variants for data center networks: A comparative study(IEEE Computer Society help@computer.org, 2012) Tahiliani, R.P.; Tahiliani, M.P.; Chandra Sekaran, K.C.Transmission Control Protocol (TCP) has been the workhorse of the Internet ever since its inception. The success of the Internet, infact, can be partly attributed to the congestion control mechanisms implemented in TCP. Though the scale of the Internet and its usage increased exponentially in recent past, TCP has evolved to keep up with the changing network conditions and has proven to be scalable and robust. However, the performance of TCP in Data Center Networks has been a major concern recently because it leads to impairments such as TCP Incast, TCP Outcast, Queue build-up and Buffer pressure. With cloud computing becoming an important part of the foreseeable future, it has become extremely important to enhance the performance of TCP in Data Center Networks and overcome these impairments. In this paper, we describe the above mentioned impairments in brief and then compare the TCP variants proposed so far to ovecome these impairments in Data Center Networks. The advantages and shortcomings of every TCP variant are highlighted with respect to its efficacy and the deployment complexity. A few open issues related to TCP's performance in Data Center Networks are also discussed. © 2012 IEEE.Item CAMP: Congestion adaptive multipath routing protocol for VANETs(2012) Raviteja, B.L.; Annappa, B.; Tahiliani, M.P.Long congestion periods, frequent link failures and hand-offs in VANETs lead to more number of packets being dropped and incur high end to end delay, there by degrading the overall performance of the network. Congestion control mechanism, though mainly incorporated in transport protocols, if coupled with the routing protocols, can significantly improve overall performance of the network. In this paper we propose Congestion Adaptive Multipath Routing Protocol (CAMP) that aims to avoid congestion by proactively sending congestion notification to the sender. The proposed CAMP routing protocol is implemented in Network Simulator-2 (NS-2) and its performance is compared with Ad-hoc On Demand Multipath Distance Vector (AOMDV) in terms of Packet Drop due to Congestion, Packet Delivery Fraction, Throughput and Average End-to-End Delay. Simulation results show that CAMP routing protocol achieves significant performance gain as compared to that of AOMDV. © 2012 Springer-Verlag.Item FARED: Fast adapting RED gateways for TCP/IP networks(2012) Tahiliani, M.P.; Shet, K.C.; Basavaraju, T.G.Random Early Detection (RED) is a widely deployed active queue management mechanism to improve the performance of the network in terms of throughput and packet drop rate. The effectiveness of RED, however, highly depends on appropriate setting of its parameters. In this paper, we propose a Fast Adapting Random Early Detection (FARED) algorithm which efficiently varies the maximum drop probability to improve the overall performance of the network. Based on extensive simulations, we show that FARED algorithm reduces the packet drop rate and achieves better throughput than Adaptive RED (ARED) and Refined Adaptive RED (Re-ARED). Moreover, FARED algorithm does not introduce new parameters to improve the performance and hence can be deployed without any additional complexity. © 2012 Springer-Verlag.