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Ammar, Mostafa H.

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Author: Almeroth, Kevin C. × Item Type: Publication × search.filters.applied.f.isSeriesOfPublicationTitle: College of Computing Technical Report Series ×

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Now showing 1 - 4 of 4
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    Scalable Delivery of Web Pages Using Cyclic Best-Effort (UDP) Multicast
    (Georgia Institute of Technology, 1997) Ammar, Mostafa H. ; Fei, Zongming ; Almeroth, Kevin C.
    The World Wide Web (WWW) has gained tremendously in popularity over the last several years. Solutions to the problem of overloaded web servers have included buying more hardware, the use of transparent server replication and mirroring, and caching of hot pages. Another technique that can be used in conjunction with these other solutions is the use of multicast for the delivery of web pages. In this work we explore the use of UDP, best-effort multicast as a delivery option. Reliability is achieved through repetitive, cyclic transmission of a requested page. This solution is expected to be most efficient when used for highly requested pages. We view this cyclic multicast technique as a delivery option that can be integrated with the traditional reliable unicast and recently proposed reliable multicast options. We first describe the architecture of an integrated web server employing all three delivery options. We then describe the cyclic multicast technique and consider the various procedures needed for its successful operation. We characterize the gains in performance achieved by our proposal through an extensive performance analysis and simulation of our technique by itself, and when integrated with the other delivery options. We also describe our experience with an implementation of a prototype cyclic multicast server and its performance over the Multicast Backbone (MBone).
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    Characterization of Mbone Session Dynamics: Developing and Applying a Measurement Tool
    (Georgia Institute of Technology, 1995) Ammar, Mostafa H. ; Almeroth, Kevin C.
    Much of our current understanding of the operational aspects and the network requirements of multicast communication derives from the MBone. As an experimental network that overlays the Internet, the MBone has served as the testbed for multicast protocols. This work has led to the development of audio and video conferencing tools that have been used extensively recently. This paper describes our efforts in developing and using a measurement tool, called Mlisten for characterizing the dynamic behavior of MBone sessions. Such a characterization will be of great benefit in understanding how any future networking infrastructure with multicast and real-time capabilities will be used. We discuss the challenges in monitoring MBone session participation and report on a methodology for pre-processing observed data to make it better reflect the true behavior of members in an MBone session. We also report on the results of using Mlisten to determine temporal, geographical and resource usage characteristics of several recent MBone sessions
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    On the Performance of a Multicast Delivery Video-On-Demand Service with Discontinuous VCR Actions
    (Georgia Institute of Technology, 1994) Ammar, Mostafa H. ; Almeroth, Kevin C.
    In most proposed architectures for Video-On-Demand (VOD) systems, the customers are serviced individually by allocating and dedicating a trans- mission channel and a set of video server resources to each customer. This approach leads to an expensive-to-operate, non-scalable system. We consider a VOD system that uses multicast delivery to service multiple customers with a single set of resources. The use of multicast requires that some interactivity and part of the on-demand nature of the system are sacrificed to achieve scalability and cost-effectiveness. Previous work has considered how VCR actions could be handled in this type of system through the provisioning of set-top box buffering. In this paper we consider a modification of the semantics of the VCR functions in order to avoid this buffering requirement. In particular we consider the provision of discontinuous VCR actions in which the duration of the action is specified in integer multiples of a specified time increment. We evaluate the performance of this system through the use of simulation and compare its performance with an individual delivery (unicast) system and a multicast system with continuous VCR actions.
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    Providing A Scalable, Interactive Video-On-Demand Service Using Multicast Communication
    (Georgia Institute of Technology, 1994) Ammar, Mostafa H. ; Almeroth, Kevin C.
    Video-On-Demand (VOD) systems are typically designed around the provision of a one-to-one connection between a customer and a video server. Such a scheme is not scalable due to bandwidth and video server resource limitations. On the other hand, it is attractive because it can provide an on-demand system and a high degree of interactivity. In this paper we propose the use of multicast communication in a VOD system wherein multiple users may be served simultaneously by a single video stream transmitted by the server. A limited amount of synchronization of customer requests is needed to further enhance the benefits of the multicast operation. Done properly this should not detract from the on-demand nature of the system. We consider how interactive features, giving the illusion of a one-to-one service, can be added to such a system at the expense of added complexity to system operation and set-top box hardware. The performance of our proposed system is investigated through the use of a simulation.