# MODELING AND SIMULATION OF A NETWORK ENVIRONMENT OVER SINGLE AND MULTIPLE LINKS

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## Background to the Study

Considerable research has been conducted to model and quantify the performance of heterogeneous services and technologies (e.g (Kawasaki et al., 2006; Tsalgatidou et al., 2006; Liu et al., 2006). Accurate measurements and analyses of network characteristics (remote data transfers) are essential for robust network performance and management. Evaluating the performance of a computer networking usually involves constructing an appropriate model to predict the heterogeneous environment behaviour via simulation model. For example, several flow-level network traffic models have been proposed to describe/stimulate (Fred et al., 2001; Cong and Wolfinger, 2006). These models have been used to study fairness, response times, queue lengths and loss probabilities under different assumptions and using a variety of mathematical techniques. Queuing theory has been widely used to model and analyze the network performance of complex systems (Puigjaner, 2003) in contrast to other studies in the literature (Barakat et al., 2002; Bu and Towsley, 2001; Kherani and Kumar, 2000). This simulation model can be used to generate representative packet traffic (one-way delays and throughput) in a live network environment or in a simulated environment.

Moreover, in the future, the integration of data and communication services, almost every Internet Ready device will be a communicable device (Zhao et al., 2005). With the availability of this infrastructure, users are now demanding and expecting more services (Barakat et al., 2003; Bu and Towsley, 2001). Convergence is pushing towards an environment that requires new investment in infrastructure and able to support the delivery of rich services (various services), applications and content (Podhradsky, 2004; Nogueira, 2006). Network deployment is growing increasing complex as the industry lashes together a mix of wired and wireless technologies into large-scale heterogeneous network architecture and as user applications and traffic continue to evolve (Heidemann et al., 2001). The successful evolution of the Internet is tightly coupled to the ability to design simple and accurate models (Barakat et al., 2002). Many factors may contribute to the congestion of network interface, such as a heavy load in the network that usually generates higher traffic (Chang and Hon, 2002). Thus, this research is critical to be conducted in order to predict and measure of remote data transfers in heterogeneous environment.

## Aims and Objectives

The main objectives of this study is on Modeling  and  Simulation of a network environment over single and multiple links.

The following are the specific objectives;

1. predict the performance of various services in order to aid technology assessment and capacity planning
2. predict the expected behavior of new services and designs through qualitative or quantitative estimates of network performance;
3. assist network administrator to prepare, propose, plan and design network topology more effective and systematic and
4. conduct What-If analysis for evaluating heterogeneous network environment performance.

## Research Questions

This study posits several research questions:

1. what is the performance level of the remote data transfers?
2.  Is the simulation model for evaluating and measuring the heterogeneous (multiple links) environment performance effective?
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