Sachin Garg - Academia.edu (original) (raw)

Papers by Sachin Garg

Research paper thumbnail of On the Throughput of 802.11b Networks for VoIP

Abstract In this paper, we study the use of IEEE 802.11 b networks for VoIP traffic. Due to the l... more Abstract In this paper, we study the use of IEEE 802.11 b networks for VoIP traffic. Due to the large fixed overhead in IEEE 802.11 b, the bandwidth available at the payload sizes typical for VoIP traffic is far less than the bandwidth available when using the network for data ...

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Research paper thumbnail of Admission control for VoIP traffic in IEEE 802.11 networks

Abstract— In this paper, we propose a metric for measuring the utilization of an IEEE 802.11b wir... more Abstract— In this paper, we propose a metric for measuring the utilization of an IEEE 802.11b wireless network and outline how this metric can be accurately estimated using data that is readily available in most Access Points. We furthermore describe how this metric can be used to ...

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Research paper thumbnail of Supporting VoIP Traffic in IEEE 802.11 WLAN with Enhanced Medium Access Control (MAC) for Quality of Service

... Control (MAC) for Quality of Service Dongyan Chen , Sachin Garg ¡ , Martin Kappes ¡ and Kisho... more ... Control (MAC) for Quality of Service Dongyan Chen , Sachin Garg ¡ , Martin Kappes ¡ and Kishor S. Trivedi ... Although EDCF is a distributed control mechanism and suit-able for wireless ad-hoc networks where an AP does not exist, it cannot provide “hard” QoS guarantees. ...

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Research paper thumbnail of An experimental study of throughput for UDP and VoIP traffic in IEEE 802.11b networks

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Research paper thumbnail of Optimal rejuvenation for tolerating soft failures

Performance Evaluation, 1996

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Research paper thumbnail of Wireless access server for quality of service and location based access control in 802.11 networks

... in 802.11 Networks Sachin Garg Avaya Labs Basking Ridge, NJ sgarg@avaya.com Martin Kappes Ava... more ... in 802.11 Networks Sachin Garg Avaya Labs Basking Ridge, NJ sgarg@avaya.com Martin Kappes Avaya Labs Basking Ridge, NJ mkappes@avaya.com MahalingamMani Avaya Inc. Milpitas, CA mmani@avaya.com Abstract ...

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Research paper thumbnail of Analysis of software rejuvenation using Markov Regenerative Stochastic Petri Net

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Research paper thumbnail of Supporting VBR VoIP Traffic in IEEE 802.11 WLAN in PCF Mode

IEEE Transactions on Wireless Communications, 2002

... Our future work thus includes the performance evaluation of the enhanced MAC schemes in suppo... more ... Our future work thus includes the performance evaluation of the enhanced MAC schemes in support of VBR ... to end delay for VBR traffic is significantly reduced compared with CBR VoIP traffic, and ... Our results also show that the performance of PCF is not sensitive to traffic load ...

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Research paper thumbnail of Minimizing Completion Time of a Program by Checkpointing and Rejuvenation

Sigmetrics Performance Evaluation Review, 1996

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Research paper thumbnail of Analysis of Preventive Maintenance in Transactions Based Software Systems

IEEE Transactions on Computers, 1998

Preventive maintenance of operational software systems, a novel technique for software fault tole... more Preventive maintenance of operational software systems, a novel technique for software fault tolerance, is used specifically to counteract the phenomenon of software “aging”. However, it incurs some overhead. The necessity to do preventive maintenance, not only in general purpose software systems of mass use, but also in safety-critical and highly available systems, clearly indicates the need to follow an analysis based approach to determine the optimal times to perform preventive maintenance. In this paper, we present an analytical model of a software system which serves transactions. Due to aging, not only the service rate of the software decreases with time, but also the software itself experiences crash/hang failures which result in its unavailability. Two policies for preventive maintenance are modeled and expressions for resulting steady state availability, probability that an arriving transaction is lost and an upper bound on the expected response time of a transition are derived. Numerical examples are presented to illustrate the applicability of the models

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Research paper thumbnail of Network survivability performance evaluation:: a quantitative approach with applications in wireless ad-hoc networks

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Research paper thumbnail of Performance and Reliability Evaluation of Passive Replication Schemes in Application Level Fault Tolerance

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Research paper thumbnail of A methodology for detection and estimation of software aging

The phenomenon of software aging refers to the accumulation of errors during the execution of the... more The phenomenon of software aging refers to the accumulation of errors during the execution of the software which eventually results in it's crash/hang failure. A gradual performance degradation may also accompany software aging. Pro-active fault management techniques such as “software rejuvenation” (Y. Huang et al., 1995) may be used to counteract aging if it exists. We propose a methodology for detection and estimation of aging in the UNIX operating system. First, we present the design and implementation of an SNMP based, distributed monitoring tool used to collect operating system resource usage and system activity data at regular intervals, from networked UNIX workstations. Statistical trend detection techniques are applied to this data to detect/validate the existence of aging. For quantifying the effect of aging in operating system resources, we propose a metric: “estimated time to exhaustion”, which is calculated using well known slope estimation techniques. Although the distributed data collection tool is specific to UNIX, the statistical techniques can be used for detection and estimation of aging in other software as well

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Research paper thumbnail of On the Throughput of 802.11b Networks for VoIP

Abstract In this paper, we study the use of IEEE 802.11 b networks for VoIP traffic. Due to the l... more Abstract In this paper, we study the use of IEEE 802.11 b networks for VoIP traffic. Due to the large fixed overhead in IEEE 802.11 b, the bandwidth available at the payload sizes typical for VoIP traffic is far less than the bandwidth available when using the network for data ...

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Research paper thumbnail of Admission control for VoIP traffic in IEEE 802.11 networks

Abstract— In this paper, we propose a metric for measuring the utilization of an IEEE 802.11b wir... more Abstract— In this paper, we propose a metric for measuring the utilization of an IEEE 802.11b wireless network and outline how this metric can be accurately estimated using data that is readily available in most Access Points. We furthermore describe how this metric can be used to ...

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Research paper thumbnail of Supporting VoIP Traffic in IEEE 802.11 WLAN with Enhanced Medium Access Control (MAC) for Quality of Service

... Control (MAC) for Quality of Service Dongyan Chen , Sachin Garg ¡ , Martin Kappes ¡ and Kisho... more ... Control (MAC) for Quality of Service Dongyan Chen , Sachin Garg ¡ , Martin Kappes ¡ and Kishor S. Trivedi ... Although EDCF is a distributed control mechanism and suit-able for wireless ad-hoc networks where an AP does not exist, it cannot provide “hard” QoS guarantees. ...

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Research paper thumbnail of An experimental study of throughput for UDP and VoIP traffic in IEEE 802.11b networks

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Optimal rejuvenation for tolerating soft failures

Performance Evaluation, 1996

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Research paper thumbnail of Wireless access server for quality of service and location based access control in 802.11 networks

... in 802.11 Networks Sachin Garg Avaya Labs Basking Ridge, NJ sgarg@avaya.com Martin Kappes Ava... more ... in 802.11 Networks Sachin Garg Avaya Labs Basking Ridge, NJ sgarg@avaya.com Martin Kappes Avaya Labs Basking Ridge, NJ mkappes@avaya.com MahalingamMani Avaya Inc. Milpitas, CA mmani@avaya.com Abstract ...

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Research paper thumbnail of Analysis of software rejuvenation using Markov Regenerative Stochastic Petri Net

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Research paper thumbnail of Supporting VBR VoIP Traffic in IEEE 802.11 WLAN in PCF Mode

IEEE Transactions on Wireless Communications, 2002

... Our future work thus includes the performance evaluation of the enhanced MAC schemes in suppo... more ... Our future work thus includes the performance evaluation of the enhanced MAC schemes in support of VBR ... to end delay for VBR traffic is significantly reduced compared with CBR VoIP traffic, and ... Our results also show that the performance of PCF is not sensitive to traffic load ...

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Research paper thumbnail of Minimizing Completion Time of a Program by Checkpointing and Rejuvenation

Sigmetrics Performance Evaluation Review, 1996

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Analysis of Preventive Maintenance in Transactions Based Software Systems

IEEE Transactions on Computers, 1998

Preventive maintenance of operational software systems, a novel technique for software fault tole... more Preventive maintenance of operational software systems, a novel technique for software fault tolerance, is used specifically to counteract the phenomenon of software “aging”. However, it incurs some overhead. The necessity to do preventive maintenance, not only in general purpose software systems of mass use, but also in safety-critical and highly available systems, clearly indicates the need to follow an analysis based approach to determine the optimal times to perform preventive maintenance. In this paper, we present an analytical model of a software system which serves transactions. Due to aging, not only the service rate of the software decreases with time, but also the software itself experiences crash/hang failures which result in its unavailability. Two policies for preventive maintenance are modeled and expressions for resulting steady state availability, probability that an arriving transaction is lost and an upper bound on the expected response time of a transition are derived. Numerical examples are presented to illustrate the applicability of the models

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Research paper thumbnail of Network survivability performance evaluation:: a quantitative approach with applications in wireless ad-hoc networks

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Performance and Reliability Evaluation of Passive Replication Schemes in Application Level Fault Tolerance

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A methodology for detection and estimation of software aging

The phenomenon of software aging refers to the accumulation of errors during the execution of the... more The phenomenon of software aging refers to the accumulation of errors during the execution of the software which eventually results in it's crash/hang failure. A gradual performance degradation may also accompany software aging. Pro-active fault management techniques such as “software rejuvenation” (Y. Huang et al., 1995) may be used to counteract aging if it exists. We propose a methodology for detection and estimation of aging in the UNIX operating system. First, we present the design and implementation of an SNMP based, distributed monitoring tool used to collect operating system resource usage and system activity data at regular intervals, from networked UNIX workstations. Statistical trend detection techniques are applied to this data to detect/validate the existence of aging. For quantifying the effect of aging in operating system resources, we propose a metric: “estimated time to exhaustion”, which is calculated using well known slope estimation techniques. Although the distributed data collection tool is specific to UNIX, the statistical techniques can be used for detection and estimation of aging in other software as well

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