Browsing by Subject "Congestion control"
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Item Open Access A simple and effective mechanism for stored video streaming with TCP transport and server-side adaptive frame discard(Elsevier, 2005) Gürses, E.; Akar, G. B.; Akar, N.Transmission control protocol (TCP) with its well-established congestion control mechanism is the prevailing transport layer protocol for non-real time data in current Internet Protocol (IP) networks. It would be desirable to transmit any type of multimedia data using TCP in order to take advantage of the extensive operational experience behind TCP in the Internet. However, some features of TCP including retransmissions and variations in throughput and delay, although not catastrophic for non-real time data, may result in inefficiencies for video streaming applications. In this paper, we propose an architecture which consists of an input buffer at the server side, coupled with the congestion control mechanism of TCP at the transport layer, for efficiently streaming stored video in the best-effort Internet. The proposed buffer management scheme selectively discards low priority frames from its head-end, which otherwise would jeopardize the successful playout of high priority frames. Moreover, the proposed discarding policy is adaptive to changes in the bandwidth available to the video stream. © 2004 Elsevier B.V. All rights reserved.Item Open Access A simulation study on congestion control for the ATM ABR service(Bilkent University, 1997) Ülkü, SezerIn this thesis, we have performed a simulation study on congestion control for the asynchronous transfer mode (ATM) available bit rate (ABR) service. Even though ABR is primarily intended for applications that can not describe their characteristics appropriately, it can be used by a wider range of applications since it provides some minimal guarantees for bandwidth. For the simulations, the ABR mechanisms specified in The ATM Forum Specification, Version 4.0 have been implemented to a great extent. Relative marking, enhanced proportional rate control (EPRCA) and efficient rate allocation algorithms (ERAA) have been realized, and their performances at ATM, TCP and application layers have been examined based on robustness, efficiency, fairness, buffer requirements and response time. The beat-down problem and large buffer requirements for the relative marking scheme have been illustrated. EPRCA was shown to be sensitive to parameters and result in oscillations in allowed cell rate. Finally, ERAA was shown to work efficiently with small buffers.