20 results for Kolahi, Samad, Conference paper

  • Performance evaluation of virtual private network protocols in Windows 2003 environment

    Narayan, Shaneel; Kolahi, Samad; Brooking, Kris; de Vere, Simon (2008-12-20)

    Conference paper
    Unitec

    Virtual Private Network (VPN) is a technology that provides secure communication for data as it transits through insecure regions of information technology infrastructure. With prolific development of the Internet, businesses nowadays implement VPN tunnels using different protocols that guarantee data authenticity and security between multiple sites connected using public telecommunication infrastructure. VPN provides a low-cost alternative to leasing a line to establish communication between sites. In this research we empirically evaluate performance difference between three commonly used VPN protocols, namely Internet Protocol Security (IPSec), Point-to-Point Tunneling Protocol (PPTP) and Secure Socket Layer (SSL). We compare performance differences in these protocols by implementing each using different algorithms in a Windows Server 2003 environment. Results obtained indicate that throughput in a VPN tunnel can range from approximately 40 to 90Mbps depending on the choice of protocol, algorithm and window size. These three attributes also govern CPU utilization of VPN servers.

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  • Simulation model, warm-up period, and simulation length of cellular systems

    Kolahi, Samad (2011-01-25)

    Conference paper
    Unitec

    In this paper, discrete event simulation by batch-means of a M/M/∞ queuing system is utilised to simulate a cellular CDMA system. The details of the simulation model, warm-up period, and simulation run time are discussed. The warm-up period is studied because it affects the accuracy of the results in simulation of communication systems. During the warm-up period-when the simulation system has not reached the steady-state situation-, the system results (eg blocking probability) vary very rapidly from zero to 0.037 for the parameters used. In the batch-means method with 10,000 calls per batch and for 50 batches (500,000 calls), the CDMA blocking probability is 0.0192 with 99% confidence interval.

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  • Bandwidth-IPSec security trade-off in IPv4 and IPv6 in Windows 7 environment

    Kolahi, Samad; Cao, Yuqing (Rico); Chen, Hong (2013-11-12)

    Conference paper
    Unitec

    Due to overheads of security algorithms used in IPSec, transferring data using IPSec is known to be significantly slow compared with open system. In this paper, we present new results on performance of IPSec using 7 encryption systems for both IPv4 and IPv6 using Windows 7 and wireless network access. For the system studied, enabling IPSec results in approximately 60% (IPv4) and 48% (IPv6) less TCP throughput compared to open system. Among encryption mechanisms, 3DES-SHA provides the highest TCP bandwidth for IPv4, while 3DES-MD5 gives the best result for IPv6. We also provide the results for UDP.

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  • Evaluation of IPv6 with IPSec in IEEE 802.11n Wireless LAN using Fedora 15 Operating System

    Kolahi, Samad; Cao, Yuqing (Rico); Chen, Hong (2013-07-07)

    Conference paper
    Unitec

    IPSec (IP Security) is a robust technique for securing communications over the Internet. Due to security algorithms used, transferring data using IPSec is known to be significantly slow. In this paper using a test bed environment for a site to site IPSec, we present new results on performance of IPSec for both IPv4 and IPv6 using Fedora 15 operating system and wireless network. Compared to open system, enabling IPSec results in approximately 50% and 40% less throughput for IPv4 and IPv6 networks respectively.

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  • The impact of wireless LAN security on performance for different windows operating systems

    Kolahi, Samad; Narayan, Shaneel; Nguyen, Du D. T.; Sunarto, Yonathan; Mani, Paul (2008-07-09)

    Conference paper
    Unitec

    This paper investigates the impact of various encryption techniques (WEP-64, WEP-128 and WPA) on performance of wireless LANs for Windows operating systems (Windows Server 2003, Windows XP and Windows Vista) and for both TCP and UDP protocols. The parameters considered are throughput and response time. The results indicate that security mechanism does influence the wireless performance and different operating systems provide various results.

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  • The Influence of WPA2 Security on the UDP performance of IPv4 and IPv6 Using 802.11n WLAN in Windows 7-Windows 2008 environment

    Kolahi, Samad; Singla, Hitesh; Ehsan, Mohd Nash; Dong, Clarence (2011-02-16)

    Conference paper
    Unitec

    The impact of WPA2 security-bandwidth trade-off for IPv4 and IPv6 on wireless 802.11n network implementing Windows 7-Windows Server 2008 is investigated. The highest point of difference between open system and WPA2 for UDP was noticed at packet size 1408 bytes where IPv4 provided 31.48 Mbps and IPv6 provided 24.33 Mbps higher throughput in the open environment. The performance of IPv4 and IPv6 are also compared.

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  • Performance comparison of category 5e vs. category 6 cabling systems for both IPv4 and IPv6 in gigabit ethernet

    Soorty, Burjiz. K.; Kolahi, Samad; Qu, Zhang; Chand, Navneet (2010-07-01)

    Conference paper
    Unitec

    The performance of category 5e and 6 cabling is compared for both IPv4 and IPv6 using Gigabit Ethernet LAN. The maximum bandwidth achieved was 700Mbps and it was for IPv4 and category 5e cabling.

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  • On Erlang capacity of CDMA systems

    Kolahi, Samad (2003-12-01)

    Conference paper
    Unitec

    In this paper, the Erlang capacity of mobile protocols such as FDMA (Frequency Division Multiple Access), TDMA (Time Division Multiple Access), and CDMA (Code Division Multiple Access) systems are compared assuming perfect power control. Methods of calculating the traffic capacity of such systems are discussed. A simulation and modeling method is used and the results are compared with previous analytical methods. The simulation result is close to analytical result although a different approach is adopted. CDMA can provide up-to 20 times more traffic capacity than FDMA and 5.3 times more traffic capacity than TDMA.

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  • Impact of SSL Security on bandwidth and delay in IEEE 802.11n WLAN Using Windows 7

    Kolahi, Samad; Cao, Yuqing; Chen, Hong (2016-07-22)

    Conference paper
    Unitec

    IPSec (IP Security) and SSL (Secure Socket Layer) are the main technologies for securing communications via the Internet. In this paper, we present new results on the performance of SSL using Windows 7 operating system under IEEE802.11n wireless network. Enabling IPSec security results on average approximately 50% less TCP throughout while enabling SSL security results on average approximately 96% less TCP throughput compared to open system. In IPSec, 3DES-SHA encrypted system outperformed AES128-SHA encrypted system with a maximum difference of 2.40 Mbps for packet size of 1408. However, in SSL, AES128-SHA and 3DES-SHA had almost the same performance.

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  • Effect of WPA2 Security on IEEE 802.11n bandwidth and round trip time in peer-peer wireless local area networks

    Li, Peng; Kolahi, Samad; Safdari, Mustafa; Argawe, Mulugeta (2011-03-22)

    Conference paper
    Unitec

    In this paper 802.11 wireless peer-peer network is evaluated for both IPv4 and IPv6 in Windows 7 and Fedora 12 operating systems. IPv4 has higher throughput than IPv6 for all packet sizes for both Windows 7 and Fedora 12 operating systems. Results further indicate that implementing WPA2 wireless security reduces bandwidth and increase delay in wireless networks.

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  • Analysis of UDP DDoS floor cyber attack and defense mechanisms on web server with Linux Ubuntu 13

    Kolahi, Samad; Treseangrat, Kiattiku; Sarrafpour, Bahman (2015-02-19)

    Conference paper
    Unitec

    Denial of Service (DoS) attacks is one of the major threats and among the hardest security problems in the Internet world. Of particular concern are Distributed Denial of Service (DDoS) attacks, whose impact can be proportionally severe. With little or no advance warning, an attacker can easily exhaust the computing resources of its victim within a short period of time. In this paper, we study the impact of a UDP flood attack on TCP throughput, round-trip time, and CPU utilization for a Web Server with the new generation of Linux platform, Linux Ubuntu 13. This paper also evaluates the impact of various defense mechanisms, including Access Control Lists (ACLs), Threshold Limit, Reverse Path Forwarding (IP Verify), and Network Load Balancing. Threshold Limit is found to be the most effective defense.

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  • Analysis of UDP DDoS cyber flood attack and defense mechanisms on Windows Server 2012 and Linux Ubuntu 13

    Treseangrat, Kiattikul; Kolahi, Samad; Sarrafpour, Bahman (2015-07-15)

    Conference paper
    Unitec

    Distributed Denial of Service (DoS) attacks is one of the major threats and among the hardest security problems in the Internet world. In this paper, we study the impact of a UDP flood attack on TCP throughputs, round-trip time, and CPU utilization on the latest version of Windows and Linux platforms, namely, Windows Server 2012 and Linux Ubuntu 13. This paper also evaluates several defense mechanisms including Access Control Lists (ACLs), Threshold Limit, Reverse Path Forwarding (IP Verify), and Network Load Balancing. Threshold Limit defense gave better results than the other solutions.

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  • Other cells interference of power controlled CDMA systems

    Kolahi, Samad (2002-12-17)

    Conference paper
    Unitec

    In this paper, using a simulation and modelling technique, the other cell interference factor is obtained and compared with previous upper bounds. The effect of propagation parameters on other cell interference is investigated. Two scenarios are studied, when the mobile chooses the nearest base station and when it chooses the least attenuation base station. The results indicate that that the other cell interference factor can be substantially less than the upper bounds obtained in previous works.

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  • UDP performance analysis of IPv4 and IPv6 on Windows Vista and Windows XP over fast ethernet peer-peer LAN

    Manford, Chris; Kolahi, Samad; Soorty, Burjiz. K.; Qu, Zhang; Chand, Navneet (2009-12-20)

    Conference paper
    Unitec

    In this paper, the performance of IPv4 and IPv6 are compared using Windows Vista and the UDP (User Datagram Protocol) throughput results are compared with Windows XP in a peer-peer environment. The results indicated that the UDP bandwidth using Windows Vista and fast Ethernet for IPv4 ranged between 26.5 and 85.6 Mbps and between 24 and 84.6 Mbps for IPv6. Windows XP bandwidth ranged from 21.8 and 86 Mbps for IPv4 and between 20.7 and 81 Mbps for IPv6.

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  • The performance of IPv4 and IPv6 using UDP on IEEE 802.11n WLANS with WPA2 security.

    Kolahi, Samad; Qu, Zhang; Soorty, Burjiz K.; Chand, Navneet (2009-07-01)

    Conference paper
    Unitec

    The IPv4 and IPv6 performance with UDP (User Datagram Protocol) on two client-server wireless 802.11n LANs implementing Windows Vista-Windows Server 2008 and Windows XP-Windows Server 2008 are compared. The impact of wireless security implementation (WPA2 security against no security) in IEEE 802.11n networks for IPv4 and IPv6 is investigated.

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  • WPA2 security-bandwith trade-off in 802.11n peer-peer WLAN for IPv4 and IPv6 using Windows XP and Windows 7 operating systems

    Kolahi, Samad; Li, Peng; Safdari, Mustafa; Argawe, Mulugeta (2012-07-01)

    Conference paper
    Unitec

    In this paper, we present new results on the performance of IEEE 802.11n using open system (no security) and WPA2 security for Windows XP and Windows 7. Enabling WPA2 security results in approximately 4.4 Mbps less TCP throughput than open system for both IPv4 and IPv6 on Windows XP and up to 2.8 Mbps less TCP throughput for Windows 7. For both open system and WPA2 security, Windows 7 provides higher IPv4 and IPv6 bandwidth than Windows XP and IPv4 provides higher bandwidth than IPv6.

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  • Performance Comparison of Defense Mechanisms Against TCP SYN Flood DDoS Attack

    Kolahi, Samad; Alghalbi, Amro A.; Alotaibi, Abdulmohsen F.; Ahmed, Saarim S.; Lad, Divyesh (2014)

    Conference paper
    Unitec

    The TCP SYN DDoS attack and defense prevention mechanisms is studied. Each prevention mechanism has some exclusive pros and cons over the others. In this paper, we have compared various defence mechanisms for preventing potential TCP SYN DDoS attacks. Router based TCP Intercept is found to provide the best defense while Anti DDoS Guardian gave the worst defese.

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  • Performance comparison of IPv4 and IPv6 in peer-peer and client server local area networks

    Kolahi, Samad; Soorty, Burjiz; Chand, Navneet; Qu, Zhang (2010-06-29)

    Conference paper
    Unitec

    In this paper, the performance of IPv4 and IPv6 are compared for both Client-Server and Peer-Peer networks. For both networks, IPv4 produced higher bandwidth for TCP protocol. For UDP, IPv4 and IPv6 showed insignificant bandwidth differences except for packet size of 384 bytes where IPv4 had better performance in client-server environment.

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  • Analysis of results in simulation and modeling of CDMA systems

    Kolahi, Samad (2007-07-01)

    Conference paper
    Unitec

    In this paper, using discrete event stochastic simulation by batch-means, new results have been obtained by analysing the sensitivity of CDMA blocking probability for a given traffic load against various number of calls per batch and confidence intervals. It is found that for the system under study one long simulation with one million call arrivals produce approximately 99% confidence in results while it needs 100,000 calls to achieve 95% confidence. For system under study and with 27 Erlang of traffic, the blocking probability is 0.0202 with 99% confidence and 0.0192 with 95% confidence. The impact of warm-up period on CDMA simulation is discussed. Situation with three tiers of neighbouring cells are considered when mobile compares three base stations and chooses the base station with the strongest signal.

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  • Performance monitoring of various network traffic generators

    Kolahi, Samad; Narayan, Shaneel; Nguyen, D.D.T; Sunarto, Y. (2011-03-31)

    Conference paper
    Unitec

    In this paper, in a laboratory environment, the performance of four network traffic generators (Iperf, Netperf, D-ITG and IP Traffic) are compared. Two computers with Windows operating systems were connected via a 100 Mbps link and for various payload sizes, ranging from 128 Bytes to 1408 Bytes, the TCP traffic on the link was measured using the various monitoring tools mentioned above. The results indicate that these tools can produce significantly different results. In the Windows environment, the bandwidth that the tools measure can vary as much as 16.5 Mbps for a TCP connection over a 100 Mbps link. For the same network set up, Iperf measured the highest bandwidth (93.1 Mbps) while IP traffic the lowest (76.7 Mbps). A comparison of capabilities of traffic generators is also provided.

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