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Computers and Communications, 1998. ISCC '98. Proceedings. Third IEEE Symposium on

Date June 30 1998-July 2 1998

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  • Proceedings Third IEEE Symposium on Computers and Communications. ISCC'98. (Cat. No.98EX166)

    Publication Year: 1998
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    Freely Available from IEEE
  • Author index

    Publication Year: 1998 , Page(s): 717 - 720
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    Freely Available from IEEE
  • On the effectiveness of path pre-computation in reducing the processing cost of on-demand QoS path computation

    Publication Year: 1998 , Page(s): 42 - 46
    Cited by:  Papers (2)  |  Patents (2)
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    Quality of service (QoS) routing algorithms have become the focus of recent research due to their potential for increasing the utilization of an integrated services packet network (ISPN) that handles requests with QoS requirements. While heuristics for determining paths for such requests have been formulated for a variety of QoS models, little attention has been given to the overall processing complexity of the QoS routing architecture. Although on demand path computation is very attractive due to its simplicity, many believe that its processing cost will be prohibitive in environments with high request rates. In this work, we first characterize the processing cost of QoS routing algorithms that use the constrained widest-shortest path heuristic to compute QoS paths in a link state based routing environment. By simulating a variety of realistic traffic conditions we investigate the effectiveness of path pre-computation in reducing the amount of routing protocol computation. We mainly want to determine how much reduction in routing processing cost is possible before the routing performance becomes unacceptably low. Our results show that path pre-computation can significantly reduce the processing cost of on-demand path computation but with a proportional routing performance loss View full abstract»

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  • A distributed routing algorithm for supporting connection-oriented service in wireless networks with time-varying connectivity

    Publication Year: 1998 , Page(s): 587 - 591
    Cited by:  Papers (9)
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    We develop and simulate a distributed dynamic routing algorithm, capable of identifying paths for establishing and maintaining connection-oriented sessions in wireless communication networks which are characterized by frequent and unpredictable changes in connectivity. Our approach is a new protocol which runs atop a protocol for connectionless datagram service and establishes circuit routes for initial connection based on a mechanism of short packets exchange and on distributed information about availability of network resources. We explore the idea of predictive rerouting in that the algorithm takes advantage of the possibility to convert a connectivity change into a “soft” failure to maintain and re-route on-going sessions. The algorithm is simulated in Opnet and results show that the “softening” of link failures can improve the performance as captured in terms of new call blocking probability and probability of forced termination of on-going sessions View full abstract»

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  • Average information staleness (AIS) as a system measure of performance

    Publication Year: 1998 , Page(s): 478 - 482
    Cited by:  Papers (1)
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    This paper introduces and defines the average information staleness (AIS) as a new measure of communication systems striving to optimize most recent reliability while operating over networks subject to delays and errors. In such settings a dynamic source needs to provide updated information at a given report rate to a number of destinations. Relevant applications include stock market report services and military command and control center situation awareness. The AIS parameter depends on the following: (1) the source report rate, (2) the report completion rate, and (3) the average and the variance of the delay. In addition, this paper shows that to optimize AIS, by minimizing its value, some counter-intuitive tradeoffs between delay and completion rate must be made. Finally, results are presented for an example system that was analyzed by simulation, which showed explicitly the tradeoffs that need to be realized when attempting to optimize the AIS measure View full abstract»

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  • A simulation study on the performance of integrated switching strategy for traffic management in ATM networks

    Publication Year: 1998 , Page(s): 13 - 18
    Cited by:  Papers (3)
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    Designing effective congestion control strategies for broadband networks is known to be difficult because of the variety of dynamic parameters involved such as link speeds, burstiness of the traffic, and the distances between traffic sources and switching nodes. We propose a traffic management scheme, which is insensitive to the propagation delay between the sources and switching nodes. We achieve this by combining connection admission control with a bandwidth allocation strategy. By seeking the cooperation of the available bit rate (ABR) sources (to limit their peak cell rate, PCR) at the time of admission of a variable bit rate (VBR) source to the network, the scheme eliminates the continuous congestion control. Our simulations show that the strategy is able to eliminate the ABR cell losses, achieves effective server and buffer utilization, and provides bounded delays to the VBR traffic (unlike the case without any controls) View full abstract»

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  • Network management and operations: application oriented management in distributed environments

    Publication Year: 1998 , Page(s): 130 - 134
    Cited by:  Papers (1)  |  Patents (8)
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    The use of application management systems has become a valuable approach in dealing with dynamic information filtering, resource allocation, and resource control. Traditionally, management systems provide the application or the user with capabilities to statically monitor and control the resources. This work presents a knowledge-based management system that offers dynamic service to distributed applications as well as dynamic control of the application's environment. It also studies the roles of different agents in an application management environment. The presented framework deals with heterogeneity of distributed environments and enables agents to utilize dynamic information regarding the resources. Agents are used as resource administrators, application agents and user agents. They utilize control mechanisms to manage the resources with respect to the application requirements, control the user's environment and monitor-control-report management information. The paradigms of control mechanism presented here exploit the agent capabilities and their communication environment View full abstract»

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  • Scheduling the access of shared variables for the two communication nodes parallel structures

    Publication Year: 1998 , Page(s): 216 - 220
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    Scheduling algorithms should be provided to order parallel processes competing to access shared variables such that the execution time of their fork-join (parallel) structure is minimum. Previous research work focused on developing scheduling algorithms for single communication node parallel structures. In this paper we introduce a heuristic scheduling algorithm called maximum remaining time (MRT) for the two communication node parallel structures View full abstract»

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  • An algorithmic approach for the planning of partial access ETSI SDH SNCP-ring subnetworks

    Publication Year: 1998 , Page(s): 193 - 197
    Cited by:  Patents (1)
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    With the development of rings employing subnetwork connection protection (SNCP-rings) numerous complex solutions can be realised in the design of survivable synchronous digital hierarchy (SDH) networks. Three algorithms for optimising the planning of equipment cost-effective SDH networks using SNCP-ring solutions have been implemented. Results indicating the efficiency of the algorithms and the factors affecting this efficiency, supported by simulation work, are presented and discussed View full abstract»

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  • Design and implementation of a TCP/IP protocol analyser

    Publication Year: 1998 , Page(s): 468 - 472
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    This paper examines the design and implementation of a TCP/IP protocol analyser using the programming language Occam. After an overview of the analyser, important design matters related with the monitoring process and the choice of data flow process decomposition as the design method are considered. The detailed examination of the design of the TCP/IP protocol analyser follows, including the channel protocols that it uses and its software structure. Important implementation issues are also highlighted. Finally, three test environments are presented, together with an analysis of the behaviour of TCP/IP protocol analyser in each of them, and some conclusions are given View full abstract»

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  • Evaluation of required queue size to support ABR service

    Publication Year: 1998 , Page(s): 525 - 529
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    The paper deals with the problem of queue size dimensioning for the ABR traffic. The analytical formulas are derived which allow to evaluate the upper bound for queue size. For this purpose the step unit function is assumed to represent the worst case of the high priority traffic (the guaranteed traffic) from the point of view of the ABR queue behaviour. The exemplary numerical results are included View full abstract»

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  • A performance comparison of the temporally-ordered routing algorithm and ideal link-state routing

    Publication Year: 1998 , Page(s): 592 - 598
    Cited by:  Papers (22)  |  Patents (53)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (84 KB)  

    We present a relative performance comparison of the temporally-ordered routing algorithm (TORA) with an ideal link state (ILS) routing algorithm. The performance metrics evaluated include bandwidth efficiency for both control and data, as well as end-to-end message packet delay and throughput. The routing algorithms are compared in the context of a dynamic, multihop, wireless network employing broadcast transmissions. The network parameters varied include network size, average rate of topological changes and average network connectivity. While the average network connectivity was found not to be a significant factor, the relative performance of TORA and ILS was found to be critically dependent on the network size, and the average rate of topological changes. The results further indicate that for a given available bandwidth-as either the size of network increases or the rate of network topological change increases, the performance of TORA eventually exceeds that of ILS View full abstract»

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  • ATM traffic generator card. An integrated solution

    Publication Year: 1998 , Page(s): 161 - 165
    Cited by:  Patents (1)
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    In this paper the design and the implementation of an ATM traffic generator system is presented. The basic principles of this document follow the architecture presented in Hontas et al. (1997). It is a PC-based system with a careful allocation of functions between hardware and software, in a way that it can work on-line at full-speed (155.52 Mbps) and, on the other hand, be flexible enough to emulate a wide range of ATM traffic profiles (VBR and CBR). The system is composed of a basic traffic generator and ATM signalling core card and four peripheral cards for the support of different physical interfaces. The architecture of the core card is open to any future modifications concerning signalling and functionality. The software of the system is running under Windows NT View full abstract»

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  • On congestion problems in digital cross-connect (DCS) transport networks

    Publication Year: 1998 , Page(s): 503 - 509
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    In today's environment where traffic demands within a network are increasing rapidly, planning and designing a network are assuming great importance. Rapidly rising traffic within the network is leading to network congestion, requiring solutions to cope with the increasing demand. We address the question of network planning and design, focusing in particular on alleviation of congestion at digital-cross connect systems (DCSs) located at the nodes of a broadband transport network. We describe a constrained routing mechanism as part of a new design strategy, employing unique dynamically changing routing constraints. Also critical in network design and planning is the knowledge of DCS capacity lost to tie-trunks, when the requirement for DCS at a given node exceeds unity, and the DCSs need to be tied together to facilitate proper cross-connects. Therefore, this paper also provides a tie-trunk analysis, leading to mathematical expressions, which can act as useful guides in the judicious planning of DCSs at the nodes of the given network View full abstract»

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  • Symmetric adaptive customer modeling in an electronic store

    Publication Year: 1998 , Page(s): 348 - 352
    Cited by:  Papers (1)  |  Patents (2)
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    Electronic Commerce (EC) is currently one of the fastest growing and most practically relevant application areas of distributed systems technologies. It is based on the economic aspects of commercial trading patterns combined with distributed computing systems technology. It is a market environment that is characterized by low transaction costs, a large number of market participants, and easy online access to services and goods offered. It also implies a set of rules and policies for the successful organization of business transactions. EC involves more than simple online transactions, it encompasses diverse activities as conducting market research, identifying opportunities and partners, cultivating relationships with customers and suppliers, document exchange and customer modeling. Our paper deals with the latter aspect of EC. We introduce here a model for developing a symmetric adaptive system for EC on the World Wide Web. Our main contribution is that the model is, by all means, symmetric: we model both customers and goods and make both their profiles change as a consequence of a customer buying a certain product. The symmetry in our model greatly simplifies the approach and the queries, giving some insights on the formalization of the allowed queries that were, in way, unexpected. Furthermore, the model itself can provide an easy-to-evaluate measure for the confidence in adapting its response to any given customer and is able to provide useful feedback to the manager, then allowing, so to speak, “manual adjustment” that can help the behaviour of the system in the future View full abstract»

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  • Burst level congestion control in ATM networks

    Publication Year: 1998 , Page(s): 258 - 264
    Cited by:  Papers (1)  |  Patents (2)
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    We present the architecture for burst level congestion control (BLCC) in ATM networks which is well suited for bursty self-similar traffic. The architecture is based upon pre-planned virtual path (PVP) set and preassigned maximal permitted route rates (MPR). The PVP set and MPR are engineered to meet QoS requirements of multi-service demand. The suggested burst level control maintains the maximal rate of cell admission on any PVP below its MPR. This is done at each PVP's source node by regulating bursts admission and by reserving the burst peak rate for each admitted burst. The reservation can be performed very fast since it is done at PVP's source node without any communication with other nodes. The MPR and PVP set are adjusted in a relatively slow, for instance hourly, timeframe adapting to the changes in the demand. The paper also presents an efficient technique for multiclass QoS engineering of burst admission that can be applied to engineer networks with large number of nodes and service classes View full abstract»

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  • An adaptive scheme for better utilization with QoS constraints for VBR video traffic in ATM networks

    Publication Year: 1998 , Page(s): 3 - 7
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    The efficient transportation of real-time variable bit rate (VBR) video traffic in high-speed networks is critical for current multimedia applications. The real-time VBR video traffic has stringent delay and cell-loss requirements. The high burstiness of the correlated VBR video traffic makes the adaptive resource management, highly desirable. This paper presents a dynamic bandwidth allocation scheme for VBR video traffic based on buffer monitoring and a simple least mean square (LMS) traffic prediction system. The goal is to reduce the frequency of the bandwidth changes and at the same time reduce the cell-loss rate (CLR) with better bandwidth utilization. Simulation results indicate that utilization of up to 0.8 can be achieved by the proposed scheme even under high source alignment for bursty VBR video traffic, with less frequent reallocations View full abstract»

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  • Performance of a micro-macrocellular system with overlapping coverage and channel rearrangement techniques

    Publication Year: 1998 , Page(s): 705 - 710
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    In this paper, a new way to manage users having different mobility in a two-tier cellular system, through the use of the techniques of overlapping coverage and channel rearrangement, is provided. Overlapping coverage areas of nearby base stations arise in cellular communications systems, especially in small cell high-capacity microcellular configurations. With overlap, some users may have access to channels at more that one base station. This enhanced access can be used to improve teletraffic performance characteristics. Channel rearrangements are used to benefit users who are in range of only one base station. An analytical model is developed to determine performance measures View full abstract»

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  • A generic legality checker and attribute evaluator for a distributed enterprise environment

    Publication Year: 1998 , Page(s): 286 - 292
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    The present state of communication networks with respect to speed and reliability and the recent growth of distributed applications have created a need for a global enterprise solution to the legality checking and attribute evaluation requirement. Traditionally, the mainframe systems provided the cohesion of all the processes with respect to the company regulations. When decentralized systems and applications became widely used the legality checking mechanism lost its central role and became a necessary component for every decentralized system. In this paper a methodology to reconnect these systems with respect to their legality checking and attribute evaluation needs is presented. A generic Legality Checking system has been developed and integrated with scheduling systems of the airline domain. It is shown that the client-server model adopted can bring back in a flexible manner the lost homogeneity of the central legacy systems View full abstract»

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  • Stability and throughput improvement for multichannel CSMA and CSMA/CD protocols with optimal bandwidth allocation

    Publication Year: 1998 , Page(s): 642 - 646
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    This paper examines appropriate protocols for high speed multiple access communication systems where the bandwidth is divided into two separate asymmetric channels. Both channels operate using slotted nonpersistent CSMA or CSMA/CD techniques. Free stations access the first channel while all retransmissions occur in the second channel. We define the stability regions and the rules for optimal bandwidth allocation among the two channels for improvement of the system performance in case of infinite population. Numerical results show that the optimal behaviour gives performance improvement as compared with the single channel system with the same capacity View full abstract»

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  • Distributed management of exclusive resources in collaborative multimedia systems

    Publication Year: 1998 , Page(s): 115 - 119
    Cited by:  Papers (2)
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    Collaborative multimedia systems encompass many Internet applications such as desktop conferencing and interactive distance learning. These applications often contain resources, such as audio, video and shared applications, that must be accessed exclusively by one participant at a time. We present a distributed algorithm that manages the access to these exclusive resources. The algorithm is based on the assumption that the transport layer provides reliable multicasting. Resources are classified into two main classes: primitive and composite. Composite resources consist of a set of two or more primitive resources. A token is associated with each resource unit, and a participant must obtain the resource's token before using the resource. To use a resource, certain permissions may be needed from certain entities such as the session coordinator, the current resource holder and, in some cases, the resource itself. The algorithm guarantees that at any given time, the resource is held by exactly one participant and the token of any resource will never be lost under all possible failure conditions View full abstract»

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  • Comparison of congestion control mechanisms for IN signalling systems

    Publication Year: 1998 , Page(s): 198 - 204
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    The evolution of increasingly complex telecommunication services, has fuelled in the last years the development of new network architectures. There is a growing interest on the evolution of the intelligent network and of the B-ISDN. The integration of the signalling systems of these two architectures will allow, in a medium term scenario, the support sophisticated services. The provision of these services will entail, on the other hand, an increase of the signalling load on the network and in particular on the service control point, the network element which contains the intelligence to control the service provision. It is therefore necessary to introduce some congestion control mechanism in order to protect such node from overload situations. A performance study relevant to two congestion control mechanisms is presented. The study has been carried out by means of simulation; moreover, theoretical upper bounds for the throughput performance of the two mechanisms have been calculated View full abstract»

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  • A low complexity baseband receiver for direct conversion burst-type radio systems

    Publication Year: 1998 , Page(s): 246 - 250
    Cited by:  Patents (1)
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    The interest for small size low complexity radio systems has resulted in examination of efficient architectures for transceiver implementation. This in turn has pushed towards smaller RF subsystems and efficient digital baseband sections. An all-digital low complexity baseband receiver is presented for a DECT radio system employing the direct conversion approach. This approach permits generation of in-phase and quadrature (I/Q) signal components. We present a novel approach for the differential detector using a finite state machine approach. The symbol timing algorithm uses oversampling only during the packet synchronization word whereas the frequency offset correction algorithm operates on the symbol rate permitting corrections up to 12% of the symbol rate. The symbol timing and the frequency correction algorithms are also implemented in an all-digital fashion emphasizing low complexity realization View full abstract»

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  • Design and performance assessment methods for third generation cellular systems

    Publication Year: 1998 , Page(s): 685 - 689
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    It is envisaged that future cellular systems, e.g., UMTS, will consist of three network segments, namely, core, access, and intelligent. In the context of this paper, we define and solve some of the design problems related to the design of the access and intelligent network segments. In addition, we present a platform that enables the assessment of the derived solutions by means of simulation. Our aim is to analyse, formally state, and theoretically formulate these problems, and to provide a platform for assessing the efficiency of the solutions to these problems View full abstract»

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  • A low-pass filter design for ATM traffic measurement and its application to bandwidth management

    Publication Year: 1998 , Page(s): 171 - 177
    Cited by:  Papers (1)
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    A low-pass filter (LPF) for ATM traffic measurement is presented and an admission control method based on it is proposed. Instantaneous rate is estimated with the LPF and the maximum instantaneous rate (MIR) observed over the monitoring period is used to determine the residual bandwidth in the method. Hence we call it the MIR method. We developed an analytical model to investigate the performance of the MIR method. We confirmed that the MIR method regulates the number of connections properly even for connections with long holding time. In addition, the MIR method is robust against long range dependent traffic, which degrades the robustness of many previously proposed methods. Because the MIR method does not assume any mathematical model and can be implemented with simple hardware, it is well suited for practical ATM switching systems View full abstract»

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