The Experts below are selected from a list of 540 Experts worldwide ranked by ideXlab platform

Fouad A Tobagi - One of the best experts on this subject based on the ideXlab platform.

  • performance evaluation of atm networks carrying constant and variable bit rate video traffic
    IEEE Journal on Selected Areas in Communications, 1997
    Co-Authors: I Dalgic, Fouad A Tobagi
    Abstract:

    In this paper, we present the performance of asynchronous transfer mode (ATM) networks supporting audio/video traffic. The performance evaluation is done by means of a computer simulation model driven by real video traffic generated by encoding video sequences. We examine the glitching that occurs when the video information is not delivered on time at the receiver; we characterize various glitching quantities, such as the glitch duration, total number of macroblocks unavailable per glitch, and the maximum unavailable area per glitch. For various types of video contents, we compare the maximum number of constant bit-rate (CBR) and constant-quality variable bit-rate (CQ-VBR) video streams that can be supported by the network while meeting the same end-to-end delay constraint, the same level of encoded video quality, and the same glitch rate constraint. We show that when the video content is highly variable, many more CQ-VBR streams than CBR streams can be supported under given quality and delay constraints, while for relatively uniform video contents (as in a videoconferencing session), the number of CBR and CQ-VBR streams supportable is about the same. We also compare the results with those obtained for a 100Base-T Ethernet Segment. We then consider heterogeneous traffic scenarios, and show that when video streams with different content, encoding scheme, and encoder control schemes are mixed, the results are at intermediate points compared to the homogeneous cases, and the maximum number of supportable streams of a given type can be determined in the presence of other types of video traffic by considering an "effective bandwidth" for each of the stream types. We consider multihop ATM network scenarios as well, and show that the number of video streams that can be supported on a given network node is very weakly dependent on the number of hops that the video streams traverse. Finally, we also consider scenarios with mixtures of video streams and bursty traffic, and determine the effect of bursty traffic load and burst size on the video performance.

I Dalgic - One of the best experts on this subject based on the ideXlab platform.

  • performance evaluation of atm networks carrying constant and variable bit rate video traffic
    IEEE Journal on Selected Areas in Communications, 1997
    Co-Authors: I Dalgic, Fouad A Tobagi
    Abstract:

    In this paper, we present the performance of asynchronous transfer mode (ATM) networks supporting audio/video traffic. The performance evaluation is done by means of a computer simulation model driven by real video traffic generated by encoding video sequences. We examine the glitching that occurs when the video information is not delivered on time at the receiver; we characterize various glitching quantities, such as the glitch duration, total number of macroblocks unavailable per glitch, and the maximum unavailable area per glitch. For various types of video contents, we compare the maximum number of constant bit-rate (CBR) and constant-quality variable bit-rate (CQ-VBR) video streams that can be supported by the network while meeting the same end-to-end delay constraint, the same level of encoded video quality, and the same glitch rate constraint. We show that when the video content is highly variable, many more CQ-VBR streams than CBR streams can be supported under given quality and delay constraints, while for relatively uniform video contents (as in a videoconferencing session), the number of CBR and CQ-VBR streams supportable is about the same. We also compare the results with those obtained for a 100Base-T Ethernet Segment. We then consider heterogeneous traffic scenarios, and show that when video streams with different content, encoding scheme, and encoder control schemes are mixed, the results are at intermediate points compared to the homogeneous cases, and the maximum number of supportable streams of a given type can be determined in the presence of other types of video traffic by considering an "effective bandwidth" for each of the stream types. We consider multihop ATM network scenarios as well, and show that the number of video streams that can be supported on a given network node is very weakly dependent on the number of hops that the video streams traverse. Finally, we also consider scenarios with mixtures of video streams and bursty traffic, and determine the effect of bursty traffic load and burst size on the video performance.

Tzi-cker Chiueh - One of the best experts on this subject based on the ideXlab platform.

  • Design and Implementation of a Real-Time Switch for Segmented Ethernets
    1997
    Co-Authors: Chitra Venkatramani, Tzi-cker Chiueh
    Abstract:

    Providing network bandwidth guarantees over an Ethernet requires coordination of the network nodes for traffic prioritization such that real-time data can have deterministic access to the network. We have shown previously how RETHER, a software-only token passing protocol can efficiently provide real-time support over a single shared Ethernet Segment. This work extends the token passing mechanism into a switched, multi-Segment Ethernet environment. This paper describes the detailed design issues involved in supporting bandwidth guarantees across multiple Segments, their solutions, and a fully operational implementation built into the FreeBSD UNIX kernel. By testing the protocol independently and as the underlying network protocol of the Stony Brook Video Server, we have verified that the bandwidth guarantees are successfully provided, with relatively low run-time overhead, for real-time connections crossing multiple Ethernet Segments. In this paper, we present our implementation experi..

Kok Soon Thia - One of the best experts on this subject based on the ideXlab platform.

  • Modelling a Video-on-Demand Service over an Interconnected LAN and ATM Networks
    2007
    Co-Authors: Kok Soon Thia
    Abstract:

    High speed networks employing ATM technology are becoming necessary as a result of increased traffic load and the transfer of multimedia information on computer networks. However, there is a large base of machines connected to local area networks (LANs) using Ethernet and FDDI technology. Thus, it is important for ATM networks and LANs to inter-operate. This paper gives an analysis of the performance issues of interconnected LAN and ATM networks under low and high load conditions, using two different scenarios. In particular, we simulate Video-on-Demand (VOD) traffic on the network and attention is given to analyse the end-to-end delays at each section of the entire network model. It is found that a severe bottleneck is over the Ethernet Segment since congestion on the Ethernet bus arises as packets are routed into the Ethernet network. Otherwise, ATM technology provides a very efficient high speed data network. 1

Darrell D. E. Longt - One of the best experts on this subject based on the ideXlab platform.

  • Swift: Using Distributed Disk Striping to Provide High VO Data Rlates. Computing Systems,4(4):405-436,1991
    2013
    Co-Authors: Luis-felipe Cabrera, Darrell D. E. Longt
    Abstract:

    ABSTRACT We present an I/O architecture, called Swift, that addresses the problem of data rate mismatches between the requirements of an application, storage devices, and the interconnection medium. The goal of Swift is to support high data rates in general purpose distributed systems. Swift uses a high-speed interconnection medium to provide high data rate transfers by using multiple slower storage devices in parallel. It scales well when using multiple storage devices and interconnections, and can use any appropriate storage technology, including high-performance devices such as disk arrays. To address the problem of partial failures, Swift stores data redundantly. Using the UNx operating system, we have constructed a simplified prototype of the Swift architecture. The prototype provides data rates that are significantly faster than access to the local SCSI disk, limited by the capacity of a single Ethernet Segment, or in the case o