Software emulation of local area and wide area networks provides an alternative method for the design of such networks and for analyzing their performance. Emulation of bridges and routers that link networks together may provide valuable information regarding network congestion, network storms and the like before putting expensive hardware into place. Such an emulation also enables students taking a networking course to develop their own client-server applications and to visualize the basic functioning of the UDP/IP and RIP protocols.This thesis builds on the emulated local area network, Metanet, created by a previous graduate student. It adds the capability of attaching routers and bridges to multiple local and non-local emulated networks so that data may be transferred between two hosts on different segments of the same LAN (via an emulated bridge) or two different networks altogether (via an emulated router). The machines running the Metanet software should support UNIX which has Berkeley's Socket interface as emulated networks on different physical machines utilize this interface for communicating. A comparison of the new networking capabilities of Metanet and other experimental systems like XINU and MINIX is researched. / Department of Computer Science

Thesis (Ph. D.)--Lehigh University, 2005. / Includes vita. Includes bibliographical references (leaves 111-117).

Orientador: Akobo Yamakani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-07-21T21:57:25Z (GMT). No. of bitstreams: 1 Nadai_LucianoPintode_M.pdf: 8791907 bytes, checksum: 75065ce4c5827da2ca719ce3105eab97 (MD5) Previous issue date: 1996 / Resumo: Este trabalho apresenta uma implementação formal e funcional da integração de LAN's com protocolos DQDB e redes ATM, baseado nas recomendações encontradas nas normas do CCITT. Concentramos nossa atenção em serviços com conexão não orientada e utilizamos a linguagem SDL para implementação virtual do procedimento proposto e posterior simulação, visando sua validação. Foi adotado o cenário direto para o suporte ao serviço não orientado à conexão em redes DQDB/ATM, implementando o elemento adaptador de protocolos(IWU) como bridge. Para isso, foi proposto um formato para o campo de endereços do quadro DQDB. Resultados das simulações de várias situações são apresentados com análises e comentários / Abstract: This work present a formal and functional implementation of DQDB-ATM LAN's integration, based on recomendations found in CCITT standards. We will treat connectionless services and the SDL language is used to implement and simulate the proposed procedures. Direct scenary has been adopted to support the connectionless services of the DQDB/ATM LAN'S, using the IWU element as a bridge. A suitable format has been proposed to the addressing field of the DQDB slot. Simulation results of several cases are analised and discussed. / Mestrado / Mestre em Engenharia Elétrica

[pt] As Redes locais sem fio (WirelessLAN ou WLAN) surgiram como uma alternativa as redes convencionais com fio (LAN), de uma forma mais flexível, de fácil configuração e boa conectividade em áreas fechadas (prediais) ou abertas (campus). Elas combinam a mobilidade do usuário com sua conexão a rede com taxas de comunicação de até 20 Mbps ou mais, empregando técnicas de espalhamento espectral (salto em frequência - FHSS ou sequência direta - DSSS) ou acesso por modulação de frequências ortogonais - OFDM, nas faixas de frequência de 900 MHz, 2.4 Ghz e 5.7 Ghz. Dependendo da tecnologia, faixa de frequência e ambiente de utilização, o alcance das WLAN pode variar de 30 a 250 metros, ou maiores distâncias com as evoluções deste padrão. O seu projeto requer o modelamento do canal de propagação em ambientes internos . Os métodos de previsão de perda de transmissão mais utilizados são de natureza semi-empírica, devido à complexidade do problema em que envolve múltiplos mecanismos de propagação como reflexão em paredes, pisos e tetos, difração em obstáculos e transmissão através de paredes e pisos. Além da perda de propagação deve ser considerado o problema do multipercursos que produz em espalhamento de retardos, o sinal recebido afetando a qualidade do sistema. / [en] The Wireless Local Area Network (WirelessLAN or WLAN) appeared as an alternative the conventio nal Local Area Network (LAN), in a more flexible way, of easy configuration and good conectividade in closed areas (property) or open areas (campus). They combine user s mobility , his/her network connection with communication taxes of up to 20 Mbps or plus, using spread spectrum techniques (Frequency Hopping - FHSS or Direct Sequence - DSSS) or access for Orthogonais Frequency Division Modulation - OFDM, in frequency range of 900 MHz, 2.4 Ghz and 5.7 Ghz. Depending on the technology, frequency range and us e atmosphere, the reach of WLAN can vary from 30 to 250 meters, or larger distances with the evolutions of this pattern. This project requests the model of the propagation channel in internal atmospheres. The methods of forecast of transmission loss more used are of semi-empiric nature, due to the complexity of the problem in that it involves multiple propagation mechanisms as reflection in walls, floors and roofs, diffraction in obstacles and transmission through walls and floors. Besides the propagation loss it should be considered the problem of the multipath that produces in dispersal of retards, the received sign affecting the quality of the system.

No description available.

<p>This thesis puts forward a new solution to provide the reliable network to the Internet Service Provider (ISP). This study mainly focuses on the ISPs network to provide reliability and the load balancing. It offers a guide line for the best reliable solution to the ISPs, individual organizations or other types of service providers which are engaged in providing reliable communications to their subscribers. These reliable services may be real time communications which include weather forecasts, tracking systems, online Internet protocol TV (IPTV) programs and many other ISPs services which are totally depend on the reliable network.</p><p>With the appearance and expansion of Internet subscribers all over the world, ISPs services are becoming more popular. The rapid increase of connection-demand and highly traffic network is the main reason behind the need to scale reliable network. To offer better solutions, a new theoretical and practical approach should be considered that can cover the reliable network.</p><p>The suggested network structure monitors the links, spreads the network traffic with multiple devices and takes a backup (redundant) link automatically when changes occur in the network topology. In order to support the redundancy, load balancing and reduce the failover time, the hot standby routing protocol (HSRP) is implemented on the suggested network. As we have analyzed that in any network, scalability bringing to raised the network traffic broadcast issue. Broadcast storms can be prevented by setting threshold values of traffic-filters. The threshold level helps to control broadcast traffic in networks.</p><p>With regard to suggested solutions, it is necessary to observe the limitations and advantages of the recommended reliable network structure. Therefore, this research will include the advantages and limitations of the techniques used to offer ISP services such as scalability, security and IPv6.</p>

This thesis puts forward a new solution to provide the reliable network to the Internet Service Provider (ISP). This study mainly focuses on the ISPs network to provide reliability and the load balancing. It offers a guide line for the best reliable solution to the ISPs, individual organizations or other types of service providers which are engaged in providing reliable communications to their subscribers. These reliable services may be real time communications which include weather forecasts, tracking systems, online Internet protocol TV (IPTV) programs and many other ISPs services which are totally depend on the reliable network. With the appearance and expansion of Internet subscribers all over the world, ISPs services are becoming more popular. The rapid increase of connection-demand and highly traffic network is the main reason behind the need to scale reliable network. To offer better solutions, a new theoretical and practical approach should be considered that can cover the reliable network. The suggested network structure monitors the links, spreads the network traffic with multiple devices and takes a backup (redundant) link automatically when changes occur in the network topology. In order to support the redundancy, load balancing and reduce the failover time, the hot standby routing protocol (HSRP) is implemented on the suggested network. As we have analyzed that in any network, scalability bringing to raised the network traffic broadcast issue. Broadcast storms can be prevented by setting threshold values of traffic-filters. The threshold level helps to control broadcast traffic in networks. With regard to suggested solutions, it is necessary to observe the limitations and advantages of the recommended reliable network structure. Therefore, this research will include the advantages and limitations of the techniques used to offer ISP services such as scalability, security and IPv6.

One of the local area network medium access control standards created by the Institute of Electrical and Electronic Engineers in IEEE Project 802 is the carrier sense multiple access with collision detection (CSMA/CD) medium access control. Numerous studies have been reported in the literature on the performance of CSMA/CD. These studies show that CSMA/CD performs well under light network load but not well at heavy load. To improve the performance of CSMA/CD under heavy load, a new concept called network partitioning is presented. Network partitioning allows the network to be partitioned into segments when under heavy load. Partition stations then act as bridges between the segments. The impact of network partitioning on network performance was tested using a simulation model of an Ethernet local area network (an implementation of the CSMA/CD medium access control). The simulation results show that network partitioning can improve the performance of CSMA/CD under heavy load.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper is a follow up to a paper presented at ITC 2002 entitled “Wireless Local Area Network for Data Telemetry from Fast Moving Nodes” by R. J. Bamberger, G. R. Barrett, R. A. Nichols, and J. L. Burbank of the Johns Hopkins University Applied Physics Laboratory, and M. H. Lauss of the Yuma Test Center at the U.S. Army Yuma Proving Ground (YPG). In that paper, network-centric data telemetry systems, specifically those based on commercial off- the-shelf (COTS) technologies such as the IEEE 802.11b Wireless Local Area Network (WLAN), were offered as an improvement over traditional frequency modulated (FM) data telemetry systems. The feasibility study of using WLANs for data telemetry considered both the radio frequency (RF) link over extended ranges and the effect due to Doppler shift. This paper describes an experiment designed to test those previous analyses.

International Telemetering Conference Proceedings / November 04-07, 1991 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Various high performance fiber optic networks have been in existence and available now for over 10 years. Virtually all of them, until recently, have been designed around the “better idea” of some single company or engineer, and therefore were or became expensive, proprietary systems, with limited support, and limited or no growth potential. Many benefits were still realized by the users in spite of that; primarily in the areas of increased bandwidth, improved security, and the capability to have data transmission over long distances. However, after 5 years of continued development and refinement, the American National Standards Institute (ANSI) X3T9.5 committee has nearly completed acceptance and final approval of the Fiber Data Distributed Interface (FDDI) specifications. The new FDDI standards have already evidenced a tremendous and eager acceptance by the end user community, and are clearly destined to replace Ethernet as the most prevalent network media. FDDI also offers additional benefits specifically of interest to the telemetry market, and therefore represents an ideal Local Area Network (LAN) technology towards which any TM installation should migrate.