2,902 research outputs found
Priorities and Pay Function Routing for a Packet Switching Network
In every network there arises the problem of choosing a path for a message so that it reaches its destination. If there are many users requesting the same channel it could be occupied and another would have to be chosen, provided that it would also be a good path and free, otherwise the message would have to queue up.
The choice of an objective function for the selection procedure of a path is part of the decision process when constructing the routing algorithm. The selection is carried out with respect to an objective function which is maximized (or minimized). There exist some useful objective functions commonly used for routing in a computer network: minimization of distance, minimization of delay or cumulative costs, maximization of throughput or reliability, etc
Performance study of voice over frame relay : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Information Engineering, Massey University, Albany, New Zealand
Frame Relay (FR) represents an important paradigm shift in modern telecommunication. This technology is beginning to evolve from data only application to broad spectrum of multimedia users and potential to provide end users with cost effective transport of voice traffic for intra office communication. In this project the recent development in voice communication over Frame relay is investigated. Simulations were carried out using OPNET, a powerful simulation software. Following the simulation model, a practical design of the LAN-to-LAN connectivity experiment was also done in the Net Lab. From the results of the simulation, Performance measures such as delay, jitter, and throughput are reported. It is evident from the results that real-time voice or video across a frame relay network can provide acceptable performance
Applications of satellite technology to broadband ISDN networks
Two satellite architectures for delivering broadband integrated services digital network (B-ISDN) service are evaluated. The first is assumed integral to an existing terrestrial network, and provides complementary services such as interconnects to remote nodes as well as high-rate multicast and broadcast service. The interconnects are at a 155 Mbs rate and are shown as being met with a nonregenerative multibeam satellite having 10-1.5 degree spots. The second satellite architecture focuses on providing private B-ISDN networks as well as acting as a gateway to the public network. This is conceived as being provided by a regenerative multibeam satellite with on-board ATM (asynchronous transfer mode) processing payload. With up to 800 Mbs offered, higher satellite EIRP is required. This is accomplished with 12-0.4 degree hopping beams, covering a total of 110 dwell positions. It is estimated the space segment capital cost for architecture one would be about 250M. The net user cost is given for a variety of scenarios, but the cost for 155 Mbs services is shown to be about $15-22/minute for 25 percent system utilization
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Game theory for dynamic spectrum sharing cognitive radio
This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel University on 21 June 2010.âGame Theoryâ is the formal study of conflict and cooperation. The theory is based on a set of tools that have been developed in order to assist with the modelling and analysis of individual, independent decision makers. These actions potentially affect any decisions, which are made by other competitors. Therefore, it is well suited and capable of addressing the various issues linked to wireless communications. This work presents a Green Game-Based Hybrid Vertical Handover Model. The model is used for heterogeneous wireless networks, which combines both dynamic (Received Signal Strength and Node Mobility) and static (Cost, Power Consumption and Bandwidth) factors. These factors control the handover decision process; whereby the mechanism successfully eliminates any unnecessary handovers, reduces delay and overall number of handovers to 50% less and 70% less dropped packets and saves 50% more energy in comparison to other mechanisms. A novel Game-Based Multi-Interface Fast-Handover MIPv6 protocol is introduced in this thesis as an extension to the Multi-Interface Fast-handover MIPv6 protocol. The protocol works when the mobile node has more than one wireless interface. The protocol controls the handover decision process by deciding whether a handover is necessary and helps the node to choose the right access point at the right time. In addition, the protocol switches the mobile nodes interfaces âONâ and âOFFâ when needed to control the mobile nodeâs energy consumption and eliminate power lost of adding another interface. The protocol successfully reduces the number of handovers to 70%, 90% less dropped packets, 40% more received packets and acknowledgments and 85% less end-to-end delay in comparison to other Protocols. Furthermore, the thesis adapts a novel combination of both game and auction theory in dynamic resource allocation and price-power-based routing in wireless Ad-Hoc networks. Under auction schemes, destinations nodes bid the information data to access to the data stored in the server node. The server will allocate the data to the winner who values it most. Once the data has been allocated to the winner, another mechanism for dynamic routing is adopted. The routing mechanism is based on the source-destination cooperation, power consumption and source-compensation to the intermediate nodes. The mechanism dramatically increases the sellerâs revenue to 50% more when compared to random allocation scheme and briefly evaluates the reliability of predefined route with respect to data prices, source and destination cooperation for different network settings. Last but not least, this thesis adjusts an adaptive competitive second-price pay-to-bid sealed auction game and a reputation-based game. This solves the fairness problems associated with spectrum sharing amongst one primary user and a large number of secondary users in a cognitive radio environment. The proposed games create a competition between the bidders and offers better revenue to the players in terms of fairness to more than 60% in certain scenarios. The proposed game could reach the maximum total profit for both primary and secondary users with better fairness; this is illustrated through numerical results
Cost Effective Routing Implementations for On-chip Networks
Arquitecturas de mĂșltiples nĂșcleos como multiprocesadores (CMP) y soluciones multiprocesador para sistemas dentro del chip (MPSoCs) actuales se basan en la eficacia de las redes dentro del chip (NoC) para la comunicaciĂłn entre los diversos nĂșcleos. Un diseño eficiente de red dentro del chip debe ser escalable y al mismo tiempo obtener valores ajustados de ĂĄrea, latencia y consumo de energĂa. Para diseños de red dentro del chip de propĂłsito general se suele usar topologĂas de malla 2D ya que se ajustan a la distribuciĂłn del chip. Sin embargo, la apariciĂłn de nuevos retos debe ser abordada por los diseñadores. Una mayor probabilidad de defectos de fabricaciĂłn, la necesidad de un uso optimizado de los recursos para aumentar el paralelismo a nivel de aplicaciĂłn o la necesidad de tĂ©cnicas eficaces de ahorro de energĂa, puede ocasionar patrones de irregularidad en las topologĂas. AdemĂĄs, el soporte para comunicaciĂłn colectiva es una caracterĂstica buscada para abordar con eficacia las necesidades de comunicaciĂłn de los protocolos de coherencia de cachĂ©. En estas condiciones, un encaminamiento eficiente de los mensajes se convierte en un reto a superar.
El objetivo de esta tesis es establecer las bases de una nueva arquitectura para encaminamiento distribuido basado en lĂłgica que es capaz de adaptarse a cualquier topologĂa irregular derivada de una estructura de malla 2D, proporcionando asĂ una cobertura total para cualquier caso resultado de soportar los retos mencionados anteriormente. Para conseguirlo, en primer lugar, se parte desde una base, para luego analizar una evoluciĂłn de varios mecanismos, y finalmente llegar a una implementaciĂłn, que abarca varios mĂłdulos para alcanzar el objetivo mencionado anteriormente. De hecho, esta Ășltima implementaciĂłn tiene por nombre eLBDR (effective Logic-Based Distributed Routing). Este trabajo cubre desde el primer mecanismo, LBDR, hasta el resto de mecanismos que han surgido progresivamente.Rodrigo MocholĂ, S. (2010). Cost Effective Routing Implementations for On-chip Networks [Tesis doctoral no publicada]. Universitat PolitĂšcnica de ValĂšncia. https://doi.org/10.4995/Thesis/10251/8962Palanci
CLASS-DEPENDENT ROUTING IN SWITCHED COMPUTER NETWORKS
Information Systems Working Papers Serie
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