37 research outputs found

    A Specific Network Link and Path Likelihood Prediction Tool

    Get PDF
    Communications have always been a crucial part of any military operation. As the pace of warfare and the technological complexity of weaponry have increased, so has the need for rapid information to assess battlefield conditions. Message passing across a network of communication nodes allowed commanders to communicate with their forces. It is clear that an accurate prediction of communication usage through a network will provide commanders with useful intelligence of friendly and unfriendly activities. Providing a specific network link and path likelihood prediction tool gives strategic military commanders additional intelligence information and enables them to manage their limited resources more efficiently. In this study, Dijkstra\u27s algorithm has been modified to allow the Queueing Network Analyzer\u27s (QNA) analysis output to act as a node\u27s goodness metric. QNA\u27s calculation of the expected Total Sojourn Time for the completion of queueing and service in a node provides accurate measurement of expected congestion. The modified Dijkstra\u27s algorithm in the Generalized Network Analyzer (GNA) is verified and empirically validated to properly deliver traffic. It appropriately generates the fastest traffic path from a start node to a destination node. This implementation includes notification if input parameters exceed the network\u27s processing capability. GNA\u27s Congestion Control displays notification and informs the user certain network input parameters must be lowered (PTR or BSTR) or where certain nodes must be improved to maintain node stability. With this unstable node identification, users can determine which node needs attention and improvements. Once this instability is removed, a good QoS is achieved and analysis proceeds

    On-board B-ISDN fast packet switching architectures. Phase 1: Study

    Get PDF
    The broadband integrate services digital network (B-ISDN) is an emerging telecommunications technology that will meet most of the telecommunications networking needs in the mid-1990's to early next century. The satellite-based system is well positioned for providing B-ISDN service with its inherent capabilities of point-to-multipoint and broadcast transmission, virtually unlimited connectivity between any two points within a beam coverage, short deployment time of communications facility, flexible and dynamic reallocation of space segment capacity, and distance insensitive cost. On-board processing satellites, particularly in a multiple spot beam environment, will provide enhanced connectivity, better performance, optimized access and transmission link design, and lower user service cost. The following are described: the user and network aspects of broadband services; the current development status in broadband services; various satellite network architectures including system design issues; and various fast packet switch architectures and their detail designs

    DSL-based triple-play services

    Get PDF
    This research examines the triple play service based on the ADSL technology. The voice over IP will be checked and combined with the internet data by two monitoring programs in order to examine the performance that this service offers and then will be compared with the usual method of internet connection.This research examines the triple play service based on the ADSL technology. The voice over IP will be checked and combined with the internet data by two monitoring programs in order to examine the performance that this service offers and then will be compared with the usual method of internet connection.

    Application of Asynchronous Transfer Mode (Atm) technology to Picture Archiving and Communication Systems (Pacs): A survey

    Full text link
    Broadband Integrated Services Digital Network (R-ISDN) provides a range of narrowband and broad-band services for voice, video, and multimedia. Asynchronous Transfer Mode (ATM) has been selected by the standards bodies as the transfer mode for implementing B-ISDN; The ability to digitize images has lead to the prospect of reducing the physical space requirements, material costs, and manual labor of traditional film handling tasks in hospitals. The system which handles the acquisition, storage, and transmission of medical images is called a Picture Archiving and Communication System (PACS). The transmission system will directly impact the speed of image transfer. Today the most common transmission means used by acquisition and display station products is Ethernet. However, when considering network media, it is important to consider what the long term needs will be. Although ATM is a new standard, it is showing signs of becoming the next logical step to meet the needs of high speed networks; This thesis is a survey on ATM, and PACS. All the concepts involved in developing a PACS are presented in an orderly manner. It presents the recent developments in ATM, its applicability to PACS and the issues to be resolved for realising an ATM-based complete PACS. This work will be useful in providing the latest information, for any future research on ATM-based networks, and PACS

    Internet QoS for DiffServ-Enabled Routers

    Get PDF
    Differentiated Service Model (DiffServ) is currently a popular research topic as a low-cost method to bring QoS to today's Internet backbone network. In this paper, the author introduces the techniques and methodologies that used to design and implement DiffServ-enabled (DS-enabled) routers. The adaptations of DS-enabled routers are designed to cater to the low Internet connectivity within Universiti Teknologi PETRONAS LAN. The author has implemented basic DiffServ setting using three CISC03725 routers. Based on these DiffServ-enabled routers, the author set up a small scale lab network to study DiffServ QoS features: priority dropping (discrimination among different service classes), QoS guarantees and measuring QoS using various formal metrics (delay and throughput). Furthermore, the author present problems encountered during study, and the proposed solutions

    An Assessment of Asynchronous Transfer Mode (ATM) Training for Educators

    Get PDF
    The purpose of this dissertation was to develop and evaluate a hypertext-based training tutorial/guide on asynchronous transfer mode (ATM) technology for use by school district educators and technology planners. A review of literature indicated training needs on new broadband technologies were not being adequately met from the point of view of an educational environment. An interactive hypertext solution was proposed, designed, and developed based on the needs of adult learners. An analysis of these needs indicated adults prefer flexibility in navigating between training topics as well as in the pace of material presentation, that is, whether to proceed at a faster or slower pace based on their personal preference, not the pace selected by an instructor. Interactive hypertext was found to support these specific needs. The procedures followed in this study included the selection of an appropriate authoring system, development of the tutorial/guide on ATM technology based on a structured methodology that focused on hypertext development, and an evaluation of the tutorial/guide. This evaluation included measuring its learning effectiveness through the use of pretests and posttests as well as an evaluation of the population\u27s preferences, attitudes, and opinions toward this type of learning (hypertext-based) as measured by a comparison of precourse and post course surveys. A case-study research approach was proposed. The results, as evaluated by a comparison of mean scores, indicated that there was a statistically significant higher mean score on the topic mastery posttest than on the pretest when the hypertext-based tutorial was given to each participant. Furthermore, the preferences toward this type training also increased significantly as measured by the comparison of means of the precourse and postcourse preference surveys

    On-board B-ISDN fast packet switching architectures. Phase 2: Development. Proof-of-concept architecture definition report

    Get PDF
    For the next-generation packet switched communications satellite system with onboard processing and spot-beam operation, a reliable onboard fast packet switch is essential to route packets from different uplink beams to different downlink beams. The rapid emergence of point-to-point services such as video distribution, and the large demand for video conference, distributed data processing, and network management makes the multicast function essential to a fast packet switch (FPS). The satellite's inherent broadcast features gives the satellite network an advantage over the terrestrial network in providing multicast services. This report evaluates alternate multicast FPS architectures for onboard baseband switching applications and selects a candidate for subsequent breadboard development. Architecture evaluation and selection will be based on the study performed in phase 1, 'Onboard B-ISDN Fast Packet Switching Architectures', and other switch architectures which have become commercially available as large scale integration (LSI) devices

    Space-Based Information Infrastructure Architecture for Broadband Services

    Get PDF
    This study addressed four tasks: (1) identify satellite-addressable information infrastructure markets; (2) perform network analysis for space-based information infrastructure; (3) develop conceptual architectures; and (4) economic assessment of architectures. The report concludes that satellites will have a major role in the national and global information infrastructure, requiring seamless integration between terrestrial and satellite networks. The proposed LEO, MEO, and GEO satellite systems have satellite characteristics that vary widely. They include delay, delay variations, poorer link quality and beam/satellite handover. The barriers against seamless interoperability between satellite and terrestrial networks are discussed. These barriers are the lack of compatible parameters, standards and protocols, which are presently being evaluated and reduced

    Analyzing the costs/tradeoffs involved between layer 2, layer 3, layer 4 and layer 5 switching

    Get PDF
    The switching function was primarily entrusted to Layer 2 of the OSI model, i.e. the Data Link Layer. A Layer 2 switch performs forwarding decisions by analyzing the MAC (Media Access Control) address of the destination segment in the frame. The Layer 2 switch checks for the destination address and transmits the packet to the appropriate segment if the address is present in its table of known destinations. If the entry for that address is not present, the switch then forwards the packet to all segments except the one on which it came from. This is known as flooding. When it gets a reply from the destination segment, it learns the location of the new address and adds it to its table of known destinations. As number of users are increasing on the network, the speed and the bandwidth of the network is being stretched to its limits. Earlier, switching was primarily entrusted to Layer 2 (Data Link Layer) of the OSI model, but now there are switches that operate at Layer 3 (Network Layer), Layer 4 (Transport Layer) and Layer 5 (Session Layer) of the OSI model. Going from one layer to the other layer does involve some costs/tradeoffs. My thesis explores the costs and tradeoffs involved with switching based on layers 2, 3, 4 and 5 of the OSI reference model
    corecore