Institute for Systems Research Technical Reports

Permanent URI for this collectionhttp://hdl.handle.net/1903/4376

This archive contains a collection of reports generated by the faculty and students of the Institute for Systems Research (ISR), a permanent, interdisciplinary research unit in the A. James Clark School of Engineering at the University of Maryland. ISR-based projects are conducted through partnerships with industry and government, bringing together faculty and students from multiple academic departments and colleges across the university.

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Author: search.filters.author.Baras, John S.Subject: search.filters.subject.network management

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Now showing 1 - 9 of 9
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    Intelligent Distributed Fault Management for Communication Networks
    (2000) Li, Hongjun; Baras, John S.; ISR; CSHCN
    In this paper, we present an intelligent, distributed fault management system for communication networks using belief networks as fault model and inference engine. The managed network is divided into domains and for each domain, there is an intelligent agent called Domain Diagnostic Agent attached to it, which is responsible for this domain's fault management. Belief network models are embedded in such an agent and under symptoms observation, the posterior probabilities of each candidate fault node being faulty is computed. We define the notion of right diagnosis, describe the diagnosis process based on this concept, and present a strategy for generation of test sequence.
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    An Automated, Distributed, Intelligent Fault Management System for Communication Networks
    (1999) Li, Hongjun; Baras, John S.; Mykoniatis, George; ISR; CSHCN
    In this paper we present a Distributed Intelligent Fault Management (DIFM) system for communication networks. The overall architecture of the proposed system is based on a distributed, cooperative, multi-agent paradigm, with probabilistic networks as the framework for knowledge representation and evidence inferencing. We adopt the management by delegation paradigm for network monitoring and integrate both hard and soft faults.
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    Delay Monitoring in ATM Networks
    (1999) Arora, Anubhav; Baras, John S.; Mykoniatis, George; Baras, John S.; ISR; CSHCN
    ATM networks provide end-to-end QoS guarantees to connectionsfor their lifetime, in the form of bounds on delays, errors andlosses. Performance management involves measurement of theseparameters accurately and taking control measures if required, toimprove performance. This is very important for real time connectionsin which losses are irrecoverable and delays cause interruptions inservice. In this paper, we concentrate on delay monitoringmechanisms. After presenting the OAM standard for ATM and a fewsolutions in the literature, problems still remaining are formulatedand directions being pursued to obtain solutions are indicated.

    This paper was published in the Proceedings of the 3rd Annual Conferenceon Advanced Telecommunications and Information Distribution ResearchProgram (ATIRP), pp. 259-263, February 1-5, 1999, University of Maryland,University College, MD.

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    Integrated, Distributed Fault Management for Communication Networks
    (1998) Baras, John S.; Li, Hongjun; Mykoniatis, G.; Baras, John S.; ISR; CSHCN
    This report describes an integrated, distributed fault management (IDFM) system for communication networks. The architecture is based on a distributed intelligent agent paradigm, with probabilistic networks as the framework for knowledge representation and evidence inferencing. A static strategy for generating the suggestive test sequence is proposed, based on which a heuristic dynamic strategy is initiated. Another dynamic strategy, formulated as a Markov decision problem, is also provided. To solve this problem, reinforcement learning techniques are investigated.
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    Managing File Subsystem Data Streams for Databases on Networked Systems
    (1996) Gupta, Sandeep K.; Baras, John S.; Kelley, Stephen; Roussopoulos, Nick; ISR; CSHCN
    One important activity for networked database systems that distribute data across several workstations is moving data between the file and network subsystems. It is possible to create data streams in the operating system kernel. If provided on a system, they allow user level processes to request transfer of data without having t copy it into the user space. This is particularly useful for data whose content or format is not modified during the transfer. In this paper we present a conservative criterion for access and control for the management of such data streams for databases in a networked environment, and define the implementation requirements for achieving the criterion. The approach is to maintain at least the current level of access management. We define the specific implementation semantics that this criterion entails.

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    Simple Calls for Flexible Constructs Using the Traditional File API
    (1996) Gupta, Sandeep; Baras, John S.; Kelley, Stephen; Roussopoulos, N.; ISR
    We present the design for a remote qos control interface to the transport protocol based on existing work for similar applications. This puts together the read/write calls from the traditional file system API and an additional primitive. The addition amounts to programming an operating system data- streaming service which may be provided as a system call or otherwise using the standard techniques. Put together these allow much more than the traditional call based control interface. The resulting interface simplifies the mechanisms for distributed control. Parts of this interface have also been implemented in our ongoing experiments with file transfer.
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    Hybrid Internet Access
    (1995) Arora, Vivek; Baras, John S.; Dillon, Douglas; Falk, Aaron D.; Suphasindhu, Narin; ISR; CSHCN
    Access to the Internet is either too slow (dial-up SLIP) or too expensive (switched 56 kbps, frame relay) for the home user or small enterprise. The Center for Satellite and Hybrid Communication Networks and Hughes Network Systems have collaborated using systems integration principles to develop a prototype of a low-cost hybrid (dialup and satellite) network terminal which can deliver data from the Internet to the user at rates up to 160 kbps. An asymmetric TCP/IP connection is used breaking the network link into two physical channels: a terrestrial dial-up for carrying data from the terminal into the Internet and a receive-only satellite link carrying IP packets from the Internet to the user. With a goal of supporting bandwidth hungry Internet applications such as Mosaic Gopher, and FTP, this system has been designed to support an Intel 80386/486 PC, any commercial TCP/IP package, any unmodified host on the Internet, and any of the routers, etc., within the Internet.. The design exploits the following three observations: 1) satellites are able to offer high bandwidth connections to large geographical area, 2) a receiver-only VSAT is cheap to manufacture and easier to install than one which can also transmit, and 3) most computer users, especially those in a home environment, will want to consume much more information than they generate. IP encapsulation, or tunneling, issued to manipulate the TCP/IP protocols to route packets asymmetrically.
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    Hybrid Network Architectures; A Framework for Comparative Analysis
    (1995) Baras, John S.; Campanella, S. Joseph; Kirkwood, Timothy J.; ISR; CSHCN
    The Global Information Infrastructure of the future will include a great variety of heterogeneous, seamlessly interconnected networks. There are strong variety of heterogeneous, seamlessly interconnected networks. There are strong technical and economic reasons predicating the emergence of these hybrid networks which will include many diverse terrestrial (tethered or wireless) and satellite networks in an interoperating configuration. This paper critically analyzes the basis for these new architectures and examines the various possibilities that will emerge in various phases in the future. A summary view is presented for these emerging hybrid architectures, the alternative components and subsystems available and the trade-offs that must be considered. The role of satellites is carefully analyzed and several conclusions are drawn. This paper will present a summary of the work and views of the Center for Satellite and Hybrid Communication Networks todate, in this important area. Specific design and performance evaluation tools being developed will also be described.
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    A Dynamic Routing Algorithm in Mixed Media Networks with Integrated Voice and Data Traffic
    (1993) Chen, Shih-Wei; Baras, John S.; ISR; CSHCN
    In this paper, we consider mixed media networks with multi-media traffic to find the optimal splitting ratio between satellite network and terrestrial network for data and voice traffic dynamically. We constantly monitor the traffic and measure the arrival rate and occupancy of every link. Based on these data, we optimize data traffic delay in a suitable time-frame under the constraints of voice traffic blocking probabilities of voice transmission links being less than specified value, which is up to system's design or users' requirements. A dynamic routing algorithm is presented.