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Local Computer Networks, 1998. LCN '98. Proceedings., 23rd Annual Conference on

Date 11-14 Oct. 1998

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  • Proceedings 23rd Annual Conference on Local Computer Networks. LCN'98 (Cat. No.98TB100260)

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    Freely Available from IEEE
  • Table of contents

    Page(s): v - vii
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    Freely Available from IEEE
  • Author index

    Page(s): 399 - 400
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    Freely Available from IEEE
  • Comparison of the Gigabit Ethernet full-duplex repeater, CSMA/CD, and 1000/100-Mbps switched Ethernet

    Page(s): 336 - 344
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    The full-duplex repeater (FDR) has previously been proposed as an alternative to half-duplex operation using CSMA/CD for controlling shared access to Gigabit Ethernet. In this paper, the basic FDR architecture is described and two extensions for traffic control are introduced. Using simulation methods, the performance of the Gigabit FDR is studied under different topologies and population sizes for a range of offered load. It is shown that the FDR provides a dramatic performance improvement over CSMA/CD (using both BEB and BLAM arbitration) at high load. The Gigabit FDR is also compared with switched Ethernet in the context of medical image retrieval. It is shown that for medical image retrieval, the performance of the Gigabit FDR is much better than 100/100 or 1000/100-Mbps switched Ethernet, and equivalent to 1000/1000-Mbps switched Ethernet for low levels of non-image background traffic View full abstract»

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  • Design and implementation of OTCA MAC protocol for high-speed point-to-point ring network

    Page(s): 345 - 352
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    In this paper, we describe the design and implementation of OTCA (ownership-tagged cell allocation) MAC protocol for a unidirectional slotted ring network with a distributed fair medium access. A point-to-point (p2p) interconnection network in a ring topology with a high-speed serial link and the sharing of network bandwidth among multiple communicating nodes offers a very promising low cost solution in the growing gigabit communication system, where it is a challenge to run high quality real-time multimedia. Some services have explicit timing requirements. The OTCA MAC protocol provides the deterministic network behavior guaranteeing the worst latency bound and the minimum bandwidth availability. On a 1.063 Gpbs p2p ring network comprising 4 nodes, the OTCA MAC protocol ensures a bandwidth of 265 Mbps for synchronous data, 232 Mbps for asynchronous data (thus a total of 497 Mbps for a mode), and the worst medium access latency is bounded with 17.46 us View full abstract»

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  • QoS routing in ad hoc wireless networks

    Page(s): 31 - 40
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    The emergence of nomadic applications have generated a lot of interest in wireless network infrastructures which support multimedia services. We propose a bandwidth routing algorithm for multimedia support in a multihop wireless network. This network can be interconnected to wired networks (e.g. ATM or the Internet) or stand alone. Our bandwidth routing includes bandwidth calculation and reservation schemes. Under such a routing algorithm, we can derive a route to satisfy the bandwidth requirement for the QoS constraint. At a source node, the bandwidth information can be used to decide to accept a new call or not immediately. This is specially important to carry out a fast handoff when interconnecting to an ATM backbone infrastructure. It enables an efficient call admission control. The simulation results show that the bandwidth routing algorithm is very useful in extending the ATM virtual circuit service to the wireless network. Different types of QoS traffic can be integrated in such a dynamic radio network with high performance View full abstract»

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  • EFR: a retransmit scheme for TCP in wireless LANs

    Page(s): 2 - 11
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    We propose a new, efficient fast retransmission (EFR) scheme for wireless LANs. Wireless LANs are becoming popular and providing an efficient protocol over a wireless link is important. In our experiments with the 2.4 GHz WaveLAN, the poor TCP performance observed was attributed to frequent expiration of the retransmission timer. To avoid unnecessary expiration of the retransmission timer, we propose a scheme in which fast retransmission is performed efficiently. The proposed modification only affects a TCP sender, and our version of TCP where the change is interoperable with existing TCP implementations. The change is especially effective in wireless LAN environments, where we have demonstrated significant improvements in throughput, 10-15%, via experiments View full abstract»

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  • A methodology to assess synchronization algorithms for distributed applications

    Page(s): 140 - 149
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    The need for algorithms providing synchronization between audio and video data was driven by the advent of multimedia applications in distributed environments. Numerous algorithms have been proposed, but there is a lack of methodologies to assess these algorithms, to compare them and to determine the algorithm best suited for a given networking and end-system environment and application. In this paper a methodology to assess synchronization algorithms for distributed multimedia applications is presented. The methodology is based on four quality of service (QoS) parameters for synchronization comprising: asynchrony, synchronization error probability, synchronization delays, and buffer requirements. An analytical analysis of these parameters is performed. A key feature of this methodology, is that it parameterizes the network, the end-system, and the application. Thus, it allows for the assessment of any synchronization algorithm independent from the network and end-system. Influences of the infrastructure on synchronization can be determined by the proposed methodology View full abstract»

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  • Effect of hidden terminals on the performance of IEEE 802.11 MAC protocol

    Page(s): 12 - 20
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    The hidden terminal problem is unique to wireless networks and as of now there is very limited understanding about its effects on network performance. Results are presented from a simulation study of the IEEE 802.11 MAC protocol when operating in the presence of hidden terminals. We also propose a framework for modeling hidden terminals which can handle complex scenarios of both mobility and static obstructions. Our simulations indicate that hidden terminals can have a very detrimental effect on the performance of the IEEE 802. 11 MAC protocol. Although the throughput is acceptable when about 10 percent of station pairs are hidden, the packet delay can increase by an order of magnitude. The performance of the protocol drops sharply when the number of hidden pairs exceeds 10 percent View full abstract»

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  • Service architecture for utilizing TINA-based public network services from the Internet environment

    Page(s): 162 - 171
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    In this paper, we assume that there will be two networks, the next-generation public network and the Internet, as the future information network infrastructure, and we propose the interworking architecture that allows users to utilize services on the next-generation public network from the Internet environment. The proposed architecture is constructed on the open distributed processing environment, based on TINA. We also constructed a platform, PLUS-TINA, especially for making use of services on the TINA-based public network from any Internet environment View full abstract»

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  • New techniques for regulating TCP flow over heterogeneous networks

    Page(s): 42 - 51
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    We study a typical network environment where TCP traffic is generated from a source connected to a LAN (e.g. Ethernet) aggregated through an IP edge router to an access network (e.g. ATM, frame relay). Congestion at the edge router occurs when the bandwidth available in the access network cannot support the aggregated traffic generated from the LAN. This paper presents a novel approach to reduce router congestion and improve TCP performance. In particular, we propose new techniques that regulate TCP acknowledgments at the edge router without changing existing TCP implementations at the end systems. Our techniques minimize buffer requirement at network edges while maximizing the throughput. Analytical and simulation results are presented in the's paper to substantiate our claims View full abstract»

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  • Fairness and delay/loss study of an end-to-end bandwidth regulation scheme

    Page(s): 315 - 324
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    The variety and heterogeneity of different approaches for Quality of Service (QoS) support on different protocol layers result in the need of a solution with end-to-end overview and regulation of dataflows in a network. Previously we proposed the concept of ROBIN (regulation of bandwidth in intra-networks) to regulate the sending bandwidth of data flows in heterogeneous campus networks by determining bottlenecks and possible rate limitations with a global knowledge of the network state based on the end-to-end operation of the mechanism. This paper presents latest results of a simulation-based performance analysis studying the throughput fairness of an enhanced version of ROBIN and evaluating the impact of the bandwidth regulation on delays and packet losses in the network View full abstract»

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  • Replication in an object-oriented system

    Page(s): 250 - 259
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    After two decades of research, reliable computing remains a property of specialized systems and too costly to implement in many applications. We present an object oriented, and fault tolerant distributed system. This system is based on open standards and hides programming complexities. Our technique for delivering replication to programmers is based on typed objects, inheritance and protocol composition. Additionally, this technique uses reliable unordered communication for message delivery View full abstract»

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  • New approach of resource management to provide integrated services over ATM networks

    Page(s): 120 - 129
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    The cooperative action between RSVP and some protocols performed on ATM networks, is one of problems that should be solved to provide integrated services over ATM networks discussed in IETF. In this paper, after describing some schemes that map RSVP into these protocols to reserve resources over ATM networks, we compare these schemes and point out some problems therein. Next, we propose a new approach referred to as “the direct lookup approach” to improve these schemes. The new approach removes overhead by the mapping between RSVP and protocols performed on ATM networks, and control messages of RSVP on ATM networks are directly examined. Finally, we discuss some issues for the implementation of this new approach View full abstract»

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  • Source-initiated adaptive routing algorithm (SARA) for autonomous wireless local area networks

    Page(s): 109 - 118
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    Conventional routing protocols used in wireline and wireless networks are not designed to operate in an autonomous (or ad hoc) wireless local area network (AWLAN) environment with asymmetric (i.e. unidirectional) links. This paper presents the design of a routing protocol called source-initiated adaptive routing algorithm (SARA), for AWLAN environments that may contain asymmetric links. To allow efficient operation in a symmetric network while ensuring correct operation in asymmetric networks, SARA supports two different modes of protocol operation: one optimized for symmetric networks and the other providing additional capabilities needed for operation in asymmetric networks at a higher cost. The ability of SARA to adapt its mode of operation and optimize its execution for each network environment is one of its major advantages and distinguishes it from existing routing protocols for, wireless networks. Furthermore, within each of its operating modes, SARA supports best-effort as well as policy-based routing View full abstract»

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  • ATM multipeer communication using a two-layer architecture

    Page(s): 182 - 189
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    Applications deploying distributed database updates, distributed simulations, shared whiteboards, and forthcoming distributed interactive multi-user games have communication needs not satisfied by most available protocols or communication subsystems. These applications are different from classical applications in that they have potentially many senders and receivers. Although there has been a lot of research on unicast and multicast protocols, only little work has been done in the area of multipeer communication, i.e. communication realizing an M:N communication service. Even fewer results are available for such a service on connection oriented technologies like ATM (asynchronous transfer mode). This paper describes the current situation, proposes a novel two-layer architecture especially suitable for ADSL and cable networks, which bridge the gap between LANs and the WAN, gives a first analysis, and presents open issues View full abstract»

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  • Performance of TCP over ABR with long-range dependent VBR background traffic over terrestrial and satellite ATM networks

    Page(s): 70 - 78
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    Compressed video is well known to be self-similar in nature. We model VBR carrying long-range dependent, multiplexed MPEG-2 video sources traffic. The actual traffic for the model is generated using fast-Fourier transform of the fractional Gaussian noise sequence. Our model of compressed video sources bears similarity to an MPEG-2 transport stream carrying video, i.e., it is long-range dependent and generates traffic in a piecewise constant bit rate manner. We study, the effect of such VBR traffic on ABR carrying TCP traffic. The effect of such VBR traffic is that the ABR capacity is highly variant. We find that a switch algorithm like ERICA+ can tolerate this variance in ABR capacity while maintaining high throughput and low delay. We present simulation results for terrestrial and satellite configurations View full abstract»

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  • Data and buffer management in ATM systems

    Page(s): 353 - 361
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    The paper discusses the handling of data traffic, at an end-user host or access concentrator performing network adaptation functions, in a high speed asynchronous transfer mode (ATM) network environment. The challenges of handling data traffic in high speed networks are the processing power and space requirements. The hardware implementation of the required protocol processing, through a high gate density application specific integrated circuit (ASIC), provides much of the processing power; however, the space requirements for data handling are still demanding. From the reasons of cost and space, on a network adapter card, often such ASICs rely upon the host for data buffers in the host memory in addition to control and configuration. Such a reliance places demand on the host memory and requires a data and buffer management mechanism that provides a framework for optimization of the memory utilization and data packet latency. The design and implementation details of one such data and buffer management mechanism, the scatter and gather mechanism, are discussed in the paper View full abstract»

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  • Performance comparison of reliable multicast protocols using the network simulator ns-2

    Page(s): 222 - 237
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    Reliable multicast protocols on top of the MBone are presently subject to intensive research. In the past, numerous protocols have been developed and their respective performance been analysed. Little progress has been made, though, to compare different approaches. We use the network simulator ns-2 to evaluate the performance of three protocols, namely scalable reliable multicast (SRM), multicast file transfer protocol (MFTP) and an enhanced version of the latter, called multicast file transfer protocol with erasure correction (MFTP/EC). We also compare the results to each other and test the suitability for multicast file distribution View full abstract»

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  • A new scheme of credit based payment for electronic commerce

    Page(s): 278 - 284
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    The paper describes a new credit card system, which presents a promise for us to develop a new method of protecting secret information, such as credit card number, PIN and identification. Our credit cards are anonymous. That is, the identity of a card holder and credit card information are not revealed during a payment process. One important feature of our system lies in the fact that, unlike normal electronic credit based systems such as SET, iKP and NetCard, the involvement of the online financial institution that runs the payment system is reduced to a minimum View full abstract»

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  • Distributed quality-of-service routing in high-speed networks based on selective probing

    Page(s): 80 - 89
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    We propose an integrated QoS routing framework based on selective probing for high-speed packet-switching networks. The framework is fully distributed and depends only on the local state maintained at every individual node. By using controlled diffusion computations, the framework captures the common messaging and computational structure of distributed QoS routing, and allows an efficient implementation due to its simplicity. Different distributed routing algorithms (DRAs) can be quickly developed by specifying only a few well-defined constraint-dependent parameters within the framework. Our simulation shows that the overhead of the proposed algorithms is stable and modest View full abstract»

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  • ABR service in ATM networks: performance comparison between adaptive stochastic and ERICA flow control schemes with guaranteed minimum cell rate

    Page(s): 61 - 69
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    Two explicit rate-based flow control schemes for congestion avoidance in ATM networks: explicit rate indication for congestion avoidance (ERICA) and a proposed adaptive stochastic (AS), are compared under heavy load conditions. Neither of the schemes dictates a particular switch architecture. The requirements tested include: utilization, queuing delay, delay variance and queue size. A simple network topology involves an ATM switching node which is modeled as a single server queuing system fed by a number of highly bursty traffic sources. Neither packet discarding, nor packet retransmission mechanisms are included. The controllable sources' allowed cell rates (ACR) have been dynamically shaped by the explicit feedback messages from the switch. The results of a simulation study are presented which suggest that the AS scheme can provide for higher priority traffic considerably shorter queuing delay, delay variance and average queue size, particularly on shorter links, with slightly lower utilization View full abstract»

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  • CommBridge-an enterprise application architecture for electronic government

    Page(s): 270 - 277
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    Driven largely by the re-engineering of Health and Human Services Information Systems for Welfare Reform and Y2K, the Commonwealth of Massachusetts is implementing an enterprise-wide infrastructure named CommBridge to meet application data and functional integration requirements mandated by law. The architecture uses a standards based infrastructure (TCP/IP, LDAP, X.500, and X.509) and 80% of the inter-application transaction requirements can be met with a few easy to use API primitives. The project's pilot phase demonstrated the feasibility of the architecture, and a broader implementation was planned Several interagency application interfaces for a new HS case management system are now in production. The architecture implements robust communication between applications using Message Oriented Middleware (MOM), a PKI security mechanism, a centralized directory for addressing and configuration information, incremental deployment, and centralized infrastructure management. Current development will incorporate enterprise level information management capabilities based on the common interchange mechanism and access to enterprise data via the WWW View full abstract»

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  • An automated resource management tool for policy-driven QoS control within integrated services intranets

    Page(s): 305 - 314
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    This paper presents the design of the automated resource management tool (ARMT), a software-based network management tool that automates the potentially complex manual task of global resource management in a mission-oriented, intranet environment. It allows the network operator to specify high level policies defining the network quality of service (QoS) that must be offered to the different applications sharing the IP network, under each operating mode of the network. The tool automatically handles resource conflicts in accordance with the high-level QoS policies defined by the network operator. It also monitors the network to detect events that may lead to deviations from the specified service policy and automatically implements proactive actions to ensure that the network delivers the required QoS. ARMT implements an innovative policy-driven QoS control technique which ensures that multimedia intranet applications will have an adaptive environment that permits them to coexist with other mission applications. The paper presents our experience with the implementation of a rapid prototype of the ARMT in a laboratory testbed environment View full abstract»

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  • High performance integrated network communications architecture (INCA)

    Page(s): 172 - 181
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    Current communication subsystem mechanisms within workstation and PC class computers are limiting network communication throughput to a percentage of the present network data rates. Though CPU and computer network speeds increased by more than an order of magnitude, the execution rate of computer functions and applications requiring network communications have increased only marginally. An integrated network communications architecture (INCA) is presented that is interoperable with all existing programs, computers and networks, and scales with network and CPU speeds. The INCA architecture minimizes internal system limitations and provides application level, as opposed to network interface level, internal machine data throughput rates near those of high speed network transmission rates. Test results of a software implementation of the INCA architecture on actual systems and networks are presented that show a 260% to 760% improvement in the application level throughput of network communicated data of workstation and PC class computers View full abstract»

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