Impacts of latency on throughput of a corporate computer network

This paper addressed the impacts of latency on good throughputs of a computer network. The networks latency contributed largely on the performance of Covenant University network. Experiment using the University network were carried out with the channel capacity, the file sizes with the distance varies to suit the performed experiment. The Mathlab/Simulink and Netcracker Professional systems were used to simulate the model network, throughput and latency. The results from simulated hypothetical corporate computer network were validated and compared to those obtained from some websites traffic, which indicated the impact of latency on good throughput of a corporate computer network decreases the efficiency of data exchange with increase in the number of users. Thus, poor data exchange in a network with constant and good throughput was better resolved through detailed knowledge of the latency

Error and Attack Tolerance of Layered Complex Networks

Many complex systems may be described not by one, but by a number of complex networks mapped one on the other in a multilayer structure. The interactions and dependencies between these layers cause that what is true for a distinct single layer does not necessarily reflect well the state of the entire system. In this paper we study the robustness of three real-life examples of two-layer complex systems that come from the fields of communication (the Internet), transportation (the European railway system) and biology (the human brain). In order to cover the whole range of features specific to these systems, we focus on two extreme policies of system's response to failures, no rerouting and full rerouting. Our main finding is that multilayer systems are much more vulnerable to errors and intentional attacks than they seem to be from a single layer perspective.Comment: 5 pages, 3 figure

Mitigating the impact of packet reordering to maximize performance of multimedia applications

We propose a solution to mitigate the performance degradation and corresponding Quality of Experience (QoE) reduction caused by packet reordering for multimedia applications which utilise unreliable transport protocols like the Datagram Congestion Control Protocol (DCCP). We analytically derive the optimum buffer size based on the applications data rate and the maximum delay tolerated by the multimedia application. We propose a dynamically adjustable buffer in the transport protocol receiver which uses this optimum buffer size. We demonstrate, via simulation results, that our solution reduces the packet loss rate, increases the perceived bandwidth and does not increase jitter in the received applications packets while still being within the application's delay limits, therefore resulting in an increased QoE of multimedia applications

A INCIDÊNCIA DO ISS E ICMS SOBRE STREAMING

RESUMO Objetivos: O objetivo principal deste trabalho é verificar a incidência do Imposto Sobre Serviço – ISS – e do Imposto sobre Circulação de Mercadoria e Serviços – ICMS – sobre a atividade de transmissão de arquivos multimídia por fluxo contínuo armazenado (streaming). Metodologia: Inicialmente, examinar-se-á a atividade objeto de estudo, partindo das lições de JAMES F. KUROSE e KIETH W. ROSS. Assim, observar-se-á a rede da perspectiva externa, tratando sobre os sujeitos que compõem a rede, e, interna, examinando as camadas de protocolos que possibilitam a comunicação. Em seguida, estabelecer-se-ão as premissas jurídicas das quais se parte, a fim de delimitar sobre quais condutas as normas tributárias dispõe e o significado das expressões nelas contidas. Analisar-se-ão, mais especificamente, os tributos possivelmente incidentes sobre a atividade objeto, enfocando, principalmente, o critério material. O método utilizado será o hipotético-dedutivo. Resultados: Finalmente, a conclusão caminhará no sentido de que a atividade não pode sofrer a incidência do ISS e do ICMS-Comunicação, pois não se trata de serviço. Ainda, a mencionada atividade também não poderia sofrer a incidência do ICMSMercadoria, pois os objetos transferidos não se enquadram no conceito constitucional de mercadoria e não há circulação. Contribuições: Verificou-se a inexistência de norma tributária que possa incidir sobre o streaming, e, em razão disso, somente a União Federal poderá, no exercício de sua competência residual, criar imposto aplicável às relações de comunicação pela Internet. PALAVRAS-CHAVE: Incidência Tributária; Imposto Sobre Serviço; Imposto sobre Circulação de Mercadoria e Serviços; Imposto Residual da União; Streaming. ABSTRACT Objective: The main objective of this work is to check the incidence of Service Tax - ISS - and the Tax on Circulation of Goods and Services - ICMS - on the streaming. Methodology: Initially examine shall be the object of study activity, based on the lessons of JAMES F. KUROSE and KIETH W. ROSS. Thus, it will be observed the network from the outside perspective, treating about subjects that make up the network and internal examining the layers of protocols that enable communication. Then set will be the legal premises of which part, in order to define on which conducts the tax rules have and the meaning of the terms contained therein. Analyze will be, more specifically, taxes possibly incident on the object activity. The method is the hypotheticdeductive. Results: Finally, the conclusion will move in the sense that the activity cannot suffer the impact of the ISS and ICMS-Communication, because it is not service. Still, the mentioned activity also could not suffer the ICMS-Merchandise, because objects transferred are not within the constitutional concept of merchandise and there is no circulation. Contributions: So checked the absence of a tax rule which may focus on activity on screen, only can the Federal Government, in the exercise of its residual powers, create tax applicable to relations of communication over the Internet. KEYWORDS: Tax incidence; Tax over service; Tax on Goods and Services; Tax Residual Union; Streamin

CEG 702-01: Advanced Computer Networks

This course provides an in-depth examination of the fundamental concepts and principles in communications and computer networks. Topics include: queuing analysis, ATM, frame relay, performance analysis of routings, and flow and congestion controls