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Local Computer Networks, 1996., Proceedings 21st IEEE Conference on

Date 13-16 Oct. 1996

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  • 21st IEEE Conference on Local Computer Networks

    Page(s): iii - x
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    Freely Available from IEEE
  • Proceedings of LCN - 21st Annual Conference on Local Computer Networks

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    Freely Available from IEEE
  • A hierarchical network storage architecture for video-on-demand services

    Page(s): 355 - 364
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    Recent advances in cable TV networks and multimedia technologies open the possibilities for network/service/content providers to offer residential customers with video-on-demand services. However, the mass storage system in supporting such services demands proper organization and management. We present a three-level hierarchical network storage architecture for the video-on-demand storage system. At the first-level (local service center, LSC) a limited number of programs with high viewing probabilities are stored while at the second-level (local central service center, LCSC) a few programs with second high viewing probabilities are stored. The third-level (central service center, CSC) contains all programs provided in the system. Based on this architecture and the program viewing probability distribution function, we use a minimum-cost function to find out the number of programs stored in the two service centers (LSC and LCSC) and the number of links among these three service centers. We also describe two program reallocation algorithms which swap programs between service centers according to the change in user request patterns View full abstract»

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  • An enhanced timed-round-robin traffic control scheme for ATM networks

    Page(s): 249 - 258
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    ATM (asynchronous transfer mode) aims at providing both guaranteed bandwidth to support real-time communications and dynamic bandwidth sharing to accommodate bursty data traffic. Achievement of this goal is vital to make ATM an enabling technology for the future integrated digital networks. This paper presents a traffic control scheme which uses a timed-round-robin cell transmission scheduling algorithm enhanced with a simple feedback flow control mechanism to realize the promised advantages of ATM networks. Specifically, with the proposed scheme, a network is able to provide each user with (1) a guaranteed bandwidth, (2) immediate access to the full link bandwidth when there is no contention from other users, and (3) freedom from cell losses. An ATM switch design is also presented which shows the feasibility of implementing the proposed scheme with today's switch architectures View full abstract»

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  • Universal packet time slot-a new paradigm of designing an ATM switch

    Page(s): 468 - 473
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    The objective of this paper is to provide a different angle of a view to relieve the stringent requirements of an electronic device in designing very high speed packet switching. This facet of the view is based on two facts; the fact that, there is a significant difference between the transmission speed offered by the lightwave technology and the processing speed of an electronic switching device, and the fact that, there are two different views of utilizing the bandwidth of a transmission line, that is, the FDM (frequency division multiplexing) technique and the TDM (time division multiplexing) technique. In the current design paradigms, internal ATM switching fabrics have being sped up to resolve output contention, regardless of their architectures. Because the speed of the electronic devices is limited by how fast an electrical signal can transmit, the speed-up will eventually either limit the number of inputs or outputs of a switching fabric or limit the speed of the transmission link. Bit-sliced techniques, that achieve a high degree of parallelism, though have been widely used to reduce the tight requirements of the electronic devices, will ultimately be limited by the small size of the ATM cells. Hence, a universal packet time slot (UPTS) is proposed to relieve the stringent requirements of an electronic device. The concept of a UPTS is discussed and the hardware complexity of implementing a UPTS switch is also presented View full abstract»

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  • A simulation study of usage-based pricing strategies for packet-switched networks

    Page(s): 278 - 288
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    This paper presents a simulation study of two proposed usage-based pricing strategies (one static, one dynamic) for computer networks. In the static pricing strategy evaluated, a price per packet is assigned and held constant over time. Results from the static strategy simulations show that network utilization decreases as the price per packet increases. Revenue, on the other hand, first increases and then falls as the price per packet increases. In the dynamic pricing strategy simulations, the price varies over time as a result of the user demand for bandwidth. As the number of users on the network increases, the price per unit of bandwidth increases. While the behaviour of the dynamic pricing scheme makes it appear promising as a pricing framework for packet-switched networks, further work is clearly required to better address the tradeoffs between network utilization, revenue, and network efficiency View full abstract»

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  • Software distribution by reliable multicast

    Page(s): 222 - 231
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    Network layer protocols such as the Internet protocol (IP) offer an unreliable, best-effort multicast datagram service in internetworks. In order to use this point-to-multipoint communication service for the software update of peripheral file servers, it has to be enhanced to guarantee a reliable delivery of files. While many other multicast applications have less stringent reliability requirements it is essential for this application that either peripheral file servers receive a file correctly, or a failure can be detected and signalled to the user. We propose an end-to-end application layer protocol building on top of a thin transport layer (UDP) and a best-effort network layer multicast service (IP), that delivers such a service and is geared towards the use in heterogeneous campus area networks. It employs sender-based implosion avoidance, and rate-based flow control in order to adapt to changing network conditions View full abstract»

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  • A reactive access control scheme at UNI for congestion control in ATM-based B-ISDN

    Page(s): 366 - 373
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    A reactive access control scheme, which controls effectively B-ISDN congestion, is proposed. The increasing number of active traffic sources results in increasing amount of feedback traffic in the current congestion control schemes. The proposed scheme resolves the problem using the generic flow control (GFC) field as a feedback notifier which informs the congestion state from a network node to a broadband network termination (B-NT) system, and includes a decision method on the actual network congestion state. We evaluate the performance of the proposed scheme through computer simulation. We compare the performance of the proposed scheme with that of the scheme using leaky bucket. As a result, the proposed scheme has the lower probability of overflow at the node output buffer with the longer cell delay at the B-NT system View full abstract»

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  • A comparative study of numerical and heuristic approaches to calculation of sustainable cell rate

    Page(s): 289 - 294
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    This paper highlights the comparative advantages of a novel numerical method for the calculation of the sustainable cell rate (SCR) parameter in ATM networks. The proposed algorithm is suited to the performance analysis of a leaky bucket (LB) fed with a wide range of discrete traffic sources, including Markov modulated Bernoulli processes (MMBP) and general on-off source models. The alternative approach, is a heuristic framework, based on the time ε-quantile function associated with a traffic source. This has also been used for finding the SCR value of the source. The effectiveness and capabilities of these two approaches are investigated, and comments on the suitability of application for each approach is given View full abstract»

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  • Multiaccess ATM network for residential and small business subscribers

    Page(s): 88 - 93
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    Shared medium-based multiaccess technology allows switches to be smaller and improves switch port granularity. It is even possible to connect multiple terminals without the initial need for an expensive ATM switch. We describe the architecture of a multiaccess ATM customer network. Considering this architecture, we introduce the connection control and management function that will play a key role in feasibility of the multiaccess ATM customer network View full abstract»

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  • A class-chest for deriving transport protocols

    Page(s): 106 - 115
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    The development of new transport protocols or protocol algorithms suffers from the complexity of the environment in which they an intended to run. Modeling techniques attempt to avoid this by simulating the environment. Another approach to promoting rapid prototyping of protocols and protocol algorithms is to provide a pre-built infrastructure that is common to transport protocols, so that the focus is placed on the protocol-specific aspects. The Meta-Transport Library is a library of C++ base classes that implement or abstract out the mundane functions of a protocol; new protocol implementations are derived from the base classes. The result is a fully viable user-level transport protocol implementation, with emphasis on modularity. The collection of base classes form a “class-chest” of tools from which protocols can be developed and studied with as little change to a normal Unix environment as possible View full abstract»

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  • A general framework for continuous media transmission control

    Page(s): 374 - 383
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    One of the major problems experienced with LAN-based videoconferencing systems is the degradation of conference latency and fidelity due to network congestion. In this paper, we present a comprehensive transmission control framework describing the relationship of latency and fidelity to properties of human perception and network congestion. We discuss how network factors such as physical link capacity and size of maximum transmission units may exacerbate the effects of congestion on the conference and how the impact of congestion can be ameliorated through judicious adaptation of the media streams' bit and message rates. Finally, we demonstrate the ability of an adaptive transmission control algorithm based upon the framework to produce low-latency, high-fidelity conferences over congested internetworks View full abstract»

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  • Adaptive resource scheduling strategies and performance analysis of broadband networks

    Page(s): 305 - 314
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    Broadband networks are fast becoming integrated into the information infrastructure. The need to transport multimedia calls requiring not only high bandwidth but also minimal loss and delay is rapidly increasing. The increased ratio of propagation delay to bit duration creates new problems in dynamic control. This paper focuses on developing adaptive control strategies and dynamic resource scheduling algorithms which would efficiently allocate (B-ISDN/ATM) network resources (e.g., bandwidth and buffers), while maintaining the best possible quality of service. Multimedia calls are classified based on crossover behavior. Simulation models used to study the system performance are presented. Performance metrics of interest include network throughput, call blocking rate, and crossover blocking probabilities View full abstract»

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  • A gracious cell discard scheme in ATM multiplexer

    Page(s): 474 - 483
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    An analytical model for the gracious cell discard (GCD) control of a finite capacity queue in ATM output multiplexer is proposed. We put a gracious cell throttle (GCT) in front of a queue (main queue: MQ). The GCT is composed of a temporary queue (TQ) and a nonlinear filter (NLF). In every time slot, a burst of cells composed of HP (high priority) and LP (low priority) arrives. Cells are classified and HP cells are not governed by the NLF and go directly to TQ, whereas LP cells are governed by the NLF. When the length of MQ is greater than zero, the NLF discards a part of LP cells based on a nonlinear filter function. The remaining LP cells are admitted to MQ along with all the HP cells within the available space of MQ. As a cell rejection policy for the overflow in MQ, we propose a partial rejection with prioritized selection (PR-PS). PR-PS operates as follows: when the number of cells in TQ exceeds the vacant space in MQ, the HP cells are accepted first within the limit of the remaining space in MQ. If there remains any vacant space in MQ after the HP cells are accepted, the LP cells can enter within the limit of the updated remaining space in MQ. Finally, we evaluate performance of the QoS (quality of service) measures related to the cell loss and delay View full abstract»

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  • Design and performance evaluation of network interconnection architectures

    Page(s): 414 - 423
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    The performance of two protocol architectures, which are often used in gateways connecting LANs (local area network) or HSNs (high speed network), is studied. The vertical views of both protocol stacks are given and two queueing network models with feedback for both protocol stacks are developed, where each queue represents a protocol layer. The arrival, service and output processes of each queue are characterized by their mean values and coefficients of variations. GI/G/1-K and GI/G/1 models are used to analyze the developed queueing network models. Several performance metrics are introduced and computed (e.g. buffer requirement, end-to-end delay, response time and power). By means of comparing the computed performance metrics the decision about the “better” protocol architecture can be made View full abstract»

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  • A study on point-to-multipoint connection control in ATM switching system

    Page(s): 449 - 457
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    In an asynchronous transfer mode (ATM) network, the point-to-multipoint connection could support distribution services such as broadcasting and multicasting services. For the point-to-multipoint connection, the ITU-T will study its signaling protocol for broadcasting, and has recommended it for a multicasting service. We survey the signaling capability of point-to-multipoint connection control for the multicasting service. The ATM network consists of ATM switching nodes, which should have service connection control functions. We consider a fully distributed ATM switching system for modularity, flexibility to burst traffic and real time processing, and propose a control method for a multicasting service in the switching system. For point-to-multipoint connection control, we adopt the dynamic bandwidth allocation method for the efficient usage of the links between subsystems, and consider an efficient scheme for utilizing the cell replication function at the nearest ATM switch to a destination party. We also propose a control procedure between suggested functional blocks for the point-to-multipoint connection in this system View full abstract»

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  • An analysis of impacts of long-term traffic correlations on congestion control in ATM-based local computer networks

    Page(s): 234 - 241
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    We analyse the impacts of the long-term correlations discovered in data and video traffic on congestion control in ATM-based local area networks based on catastrophe theory. Our work shows that long-term correlations may cause the network performance to degrade catastrophically even if the cell rate of the traffic source can be adjusted dynamically according to the network load and the peak cell rate can be bounded effectively. Experimental evidence exists supporting our analytical results. Therefore, without taking traffic correlations into account, congestion control and quality-of-service guarantees may not be effective View full abstract»

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  • A multicast tree algorithm considering maximum delay bound for real-time applications

    Page(s): 172 - 181
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    For many multimedia multicast applications, especially those requiring real-time traffic, it is important that the maximum delay bound requirement between any pair of group members be satisfied. Most studies on multicast routing have been based on a single multicast tree (a shortest path tree or a minimal Steiner tree) approach. By using only a single multicast tree for a multicast group, satisfying the maximum delay bound requirement is nearly impossible. To fulfill these requirement, we adopt the multiple multicast tree concept whose disadvantage is the high tree maintenance cost. Since the tree maintenance cost is proportional to the number of multicast trees for a multicast group, it is necessary to minimize the number of multicast trees. In this paper, we formulate the delay-bounded multicast tree (DBMT) problem whose main objectives are to satisfy an application's maximum delay bound among the group members and to minimize the number of multicast trees needed for a group communication. We categorize the DBMT problem according applications' needs into two subproblems, the shortest path tree-based DBMT (SPT DBMT) and the minimal Steiner tree-based DBMT (MST DBMT) problems. For the DBMT subproblems, we prove the NP-hardness and propose heuristic algorithms. For the performance analysis, simulations were performed View full abstract»

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  • A fuzzy policing mechanism for still picture in ATM networks

    Page(s): 40 - 47
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    The asynchronous transfer mode (ATM) technique has been accepted as a basis for the future B-ISDN networks. In ATM networks, all information is packetized and transferred in small packets of fixed length, called cells. The packetized information transfer, without flow control between the user and the network and the use of statistical multiplexing, results in the need of a policing mechanism to control the traffic parameters of each virtual connection in order to guarantee the required quality of service (QoS). The proposed parameters for monitoring the source traffic characteristics are the mean cell rate, the peak cell rate or the peak burst duration. Policing of the peak cell rate is generally not complex and can be achieved by using a cell spacer or other policing mechanisms (PMs). Monitoring the mean cell rate is more difficult. It is intended to improve the link utilization when it has to handle bursty traffic sources. We propose a policing mechanism called the fuzzy policing mechanism (FPM), by applying fuzzy set theory to police the mean cell rate of the still picture source in ATM networks. The performance evaluation via simulation shows that the FPM efficiently control the mean cell rate of the still picture source. The proposed FPM shows a good response behavior against parameter variations. The selectivity characteristics of the FPM approach the ideal characteristics required for a PM View full abstract»

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  • A novel intra-media synchronization mechanism for multimedia communications

    Page(s): 69 - 76
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    Multimedia communications often require intra-media synchronization for video data to prevent potential playout discontinuity resulting from network delay variation (jitter) while still achieving satisfactory playout throughput. We propose a neural-network-based intra-media synchronization mechanism, called neural network smoother (NNS). The NNS is composed of a neural network (NN) traffic predictor, an NN window determinator, and a window-based playout smoothing algorithm. The NN traffic predictor employs an on-line-trained backpropagation neural network (BPNN) to periodically predict future traffic characteristics. With the predicted traffic characteristics, the NN window determinator determines the corresponding optimal window by means of an off-line-trained BPNN in an effort to achieve a maximum of the playout quality (Q) value. The window-based playout smoothing algorithm then dynamically adopts various playout rates according to the window and the number of packets in the buffer. Compared to two other playout approaches, simulation results show that NNS achieves high-throughput and low-discontinuity playout under a variety of traffic arrivals View full abstract»

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  • Designing a virtual access control configuration protocol for implementation over ISDN and shared-media networks

    Page(s): 116 - 125
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    The encroachment of digital technology into our lifestyle and corporate environment has given rise to the need for individuals to safeguard personal information, and for organizations to protect trade-secret information either stored in computers or transmitted over LANs and WANs. A secure network and communication environment requires the services of encryption mechanisms, user password authentication, and network and user-interface based access control schemes that prevent unauthorised access to application programs and operating systems. While various encryption and authentication security mechanisms have garnered a lot of development effort, access control schemes using a virtual dedicated-media network system have not been fully developed. A dedicated-media network enables the authorization of access based on non-repudiate authenticity of the source. This capability presently cannot be implemented in shared-media networks. The paper introduces a a virtual access control configuration protocol (VACCP) which provides a dynamic security access authorization mechanism. The VACCP performs token-basad access security control to an application's user-interface resources. The VACCP security program is designed to control remote access for both the shared-media and dedicated-media mode of communication. The VACCP security measures are implemented as a network session-layer protocol which governs the access capability and assigns access authorization to each application program on a per-user-basis View full abstract»

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  • Characterization and control of highly correlated traffic in high speed networks

    Page(s): 19 - 27
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    By assuming network traffic to be independent from each other, the analysis of network performance can be simplified. However, the real traffic sources may have some correlation which makes their behavior tend to converge or diverge. This phenomenon has a tremendous influence on congestion control. In this paper, we explain the possible reasons for correlated behavior, namely, top-down and client-server correlation, and analyze their impacts. We also use the rapid matrix-geometric solution to investigate the cost to pay when applying the leaky bucket input control scheme to the independent traffic sources (e.g. Poisson) and the correlated traffic sources (such as on-off and HAP (hierarchical arrival process)) View full abstract»

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  • Analysis and optimization of a Banyan based ATM switch by simulations

    Page(s): 268 - 277
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    The main concern in designing the switching fabrics used in asynchronous transfer mode (ATM) technology are speed, throughput, delay and variance of delay for a given bandwidth. We analyze the performance by simulations of ATM switch based on Banyan network in the uniform traffic condition. We compare the analytical results obtained from the three-state model by Yan and Jenq (see MS Thesis, Dept. of Electrical and Computer Engineering, Portland State University, Portland, Oregon, 1995) to the simulation results. We propose non-blocking first stage (NBFS) to increase the throughput. In the NBFS scheme, internal blocking in the switching element (SE) of the first stage is avoided. We extend the idea of the priority scheme proposed by Yan and Jenq by proposing an enhanced priority (EP) scheme. In the EP scheme, we give priority to the packet blocked the greater number of times. We simulated the switch with a combined NBFS and EP scheme. The results shows that the throughput increases, and the variance of delay decreases significantly. We simulated the single buffer Banyan network with mixed voice and data traffic We simulated the Banyan network with the proposed double buffer switching element to increase the throughput and decrease the delay and variance of delay, of delay sensitive voice packet in a mixed traffic condition View full abstract»

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  • Performance analysis of application-level traffic shaping in a real-time multimedia conferencing system on Ethernets

    Page(s): 433 - 442
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    Many real-time, multimedia applications (e.g., teleconferencing) have been successful deployed over the Internet and its overlayed multicast backbone network (MBONE). However poor, unpredictable transfer performance of the continuous media in Internet is common and inevitable due to the intrinsic “best-effort” transport techniques used. Before the full-blown ATM networks or any other networks with QoS offerings are in place, Ethernets are still the most popular networks in today's office environments. We investigate how application-level traffic shaping (spacing) can help to reduce the possibly drastic performance degradation of real-time multimedia conferencing applications on a heavily-loaded Ethernet. An experimental testbed is constructed and all the application software is implemented in our laboratory. Performance results measured from the testbed are presented to provide insights of how the performance degradations occur and to illustrate how a real-time application can lessen the situation View full abstract»

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  • An error-control scheme for a multicast protocol based on round-trip time calculations

    Page(s): 212 - 221
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    In contrast to traditional one-to-one applications, distributed multimedia applications are based on communication scenarios that involve huge but often limited groups of participants. In general, tele-teaching and virtual reality scenarios require multicasting capabilities that have to deal with reliable data, e.g., simulation data, in addition to isochronous data, e.g., audio or video, that allow for losses depending an the compression technique or color tables. In particular, reliable control messages are needed for multicast signalling purposes. Existing networks have to be enhanced by integrating reliable multicast data transmission protocols to overcome this deficiency. The presented approach provides a network independent error-control scheme for a multicast protocol, offering a high stability in the local area, and an adaptable solution for metropolitan and wide area networks View full abstract»

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