As FPGA densities continue to improve, single chips are becoming capable of implementing larger and more complex systems. Even today these systems may include several processors working in conjuction with a handful of other standard interfaces or custom modules. Additional system complexity naturally leads to added complexity throughout the different design and implementation stages. Attempting to design such a system while maintaining high performance and within a reasonable time frame is becoming more and more difficult. Architectural design approaches ranging from direct module interconnection to sophisticated bus schemes have been used to build such systems, all with their own trade-offs. Often direct module interconnection results in the best overall performance but at the cost of design time and flexibility. Bus schemes on the other hand attempt to simplify the integration of the different hardware modules and allow for a more modular design approach. However, since the bus is a single shared interconnection medium, a practical limit is placed on the system's acheivable throughput. A relatively new architectural approach to system design involves a network-based communication infrastructure. A network-based interconnect scales much better than the shared bus and provides a potential increase in system throughput capabilites. An effective approach would be one that can provide the throughput capabilities of direct interconnect, the modular design advantages of the shared bus, and the flexibility to adapt to different system requirements while maintaining lightweight communication. A design infrastructure that attempts to meet these requirements has been developed. This infrastructure is based on a circuit-switched network architecture. The circuit-switching aspect allows two nodes, or modules, to temporarily establish a direct and dedicated connection for high-throughput data transfer. The network-based topology allows this to occur without tying up all the interconnect resources as other routes can be used to connect the other nodes. Each node is connected to the network via a well-defined interface therefore allowing for modular design. Flexibility is built into the architecture to accommodate many different topology configurations. Lightweight protocols and handshaking mechanisms are used to establish node-to-node connections, and initiate and terminate data transfers. Two different example applications have been implemented with this network-based interconnect: one that involves the use of a single resource that must be shared among different modules, and another that has high system bandwidth requirements and dynamically schedules the use of functionally identical resources. These implementations were then compared against that of a bus- ased approach. Both applications illustrate the effectiveness of this network architecture in SoC implementation.

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Spurred by change in government regulations and to leverage lower-cost technology and services, many land mobile radio (LMR) operators have begun transitioning from circuit-switched to packet-switched backbone networks to handle their future communication needs. Due to the unique demands of packet-switched backbone networks for LMR, it may not be wise to carry over the previously implemented security methods used with circuit-switch systems or to treat an LMR backbone as a regular packet-switched network. This thesis investigates security in packet-switched LMR backbone networks to identify security issues in packet-switched LMR networks and provide possible solutions for them. Security solutions that are examined include different types of virtual private networks (VPNs), various encryption and keying procedures for safe communication, and logic behind how and where to implement security functions within the network. Specific schemes examined include IP Security (IPSec), OpenVPN, Virtual Tunnel (VTun), and Zebedee. I also present a quantitative analysis of the effects that the solutions have on packet-switched networks, in terms of link utilization, and on voice traffic, in terms of delay and delay jitter. In addition, I evaluate, in general terms, the additional cost or complexity that is introduced by the different security solutions. Simulation with OPNET Modeler was used to evaluate how the various security schemes affect voice communication and network performance as a whole. Since OPNET Modeler does not provide models of security functions, the source code of the transceiver system models was modified to introduce additional overhead that is representative of the various security solutions. Through experimentation, simulation, and analysis of the security schemes considered, it was found that the most effective security scheme overall for a packet-switched LMR backbone network would either be IPSec or OpenVPN implemented at the base stations and end-hosts. Both security schemes provide strong encryption, flexibility, and are actively supported. However, if bandwidth is scarce and flexibility is less important, then a security solution with less overhead, such as VTun, should be considered. Thus, one has to balance performance with security to choose the most effective security solution for a particular application. / Master of Science

Orientador: Helio Waldman / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-06T02:56:20Z (GMT). No. of bitstreams: 1 Campelo_DivanilsonRodrigodeSousa_D.pdf: 945421 bytes, checksum: 52541c616bcfcfd8ae2d0a50c597fcc3 (MD5) Previous issue date: 2006 / Resumo: Investigamos o problema de estimar valores de probabilidades de bloqueio em redes de caminhos ópticos com topologias lineares. Apresentamos um melhor substituto para a suposição de independência de enlaces em redes de topologia linear: a suposição de independência de objetos. Apresentamos a prova assintótica desta suposição para redes lineares infinitas com um único canal, e mostramos que a expressão assintótica é uma aproximação muito boa para anéis finitos de qualquer tamanho. Para o caso de múltiplos comprimentos de onda, apresentamos novas aproximações de carga reduzida para anéis WDM com restrição de continuidade de comprimento de onda. Para anéis com conversão plena de comprimentos de onda, propomos um método matricial inovador que permite cálculos exatos de probabilidades de bloqueio e taxa de ocupação nestas redes. Um método "escalável" para a obtenção da constante de normalização do modelo clássico de Erlang também é apresentado. Por fim, analisamos o desempenho de meios lineares bloqueantes. Apresentamos expressões exatas para o throughput em meios compartimentalizados e não-compartimentalizados, e quantificamos os ganhos de compartimentalização em meios lineares / Abstract: We address the problem of estimating blocking probabilities in optical path networks with linear topologies. We present a better substitute for the link independence assumption in networks with linear topology: the object independence assumption. We present an asymptotic proof of this assumption for in?nite single-channel networks, and we show that the asymptotic expression is a very good approximation for ?nite rings with any size. In the case of multiple wavelengths, we present new reduced load approximations for WDM rings with wavelength continuity constraint. For rings with full wavelength conversion, we propose an innovative matrix-based method for calculating exact values of blocking probabilities and occupancy rates in such networks. A scalable method for deriving the normalization constant of the Erlang¿s classical model is also presented. Finally, we analyze the performance of linear blocking media. We present exact expressions for the throughput in slotted and unslotted media, and we quantify the slotting gains in linear media / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica