Lab 1: Evaluating Internet Connection Choices for a Small Home PC Network Objective
This lab teaches the basics of using OPNET IT Guru. OPNET IT Guru’s user-friendly interface with drag-and-drop features enable students to effectively model, manage, and troubleshoot real-world network infrastructures. We investigate application performance and capacity planning, by changing the link speed between a home LAN and its ISP.
OPNET’s IT Guru provides a Virtual Network Environment that models the behavior of networks, including its routers, switches, protocols, servers, and individual applications. The Virtual Network Environment allows IT managers, network and system planners, and ...view middle of the document...
544 Mbps. (Although modems, cable modems, and DSL connections often are advertised as being faster, these numbers are realistic throughput rates that users typically obtain in practice. Modem connections cost about $25 per month, while cable modem and DSL connections cost about $50 per month, and a T1 line costs several hundred dollars per month.) For each scenario, you will set the download speed in the simulation model, run a simulation, and view the results. You will be addressing the question of whether faster connections are worth higher prices for the home network.
Step 1: Open Lab 1 IT Guru consists of projects and scenarios. Each scenario represents the different what-if analysis performed by the users. Scenarios may contain different versions of the same network or models of different networks. A project consists of one or more network scenarios. In this lab, you will create 4 different scenarios comparing application performance with different connection speeds to the ISP. 1. Start IT Guru. 2. Select File Open… and make sure Project is selected from the pull-down menu at
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the top. 3. Scroll down to the project named Home_LAN, select it and click OK. Note: If you do not see the project file, then make sure you have downloaded the lab files. Then unzip the file and add the unzipped lab files directory by going to File Model File Add Model Directory and selecting that directory. The project should now be added.
The figure above shows the simulated network. While the Pat Lee case in Chapter 1 (Refer to Business Data Networks and Telecommunications by Professor Ray Panko) has two PCs, there are three PCs doing different tasks in this network. Each PC connects to the family’s 100 Mbps Ethernet switch via a UTP connection. The switch connects to the router, also via UTP. (In the Pat Lee case in Chapter 1, the switch and router are combined in a gateway. The two are shown as separate here to make the logic easier to see.) The cable modem is not shown; it is implicit in the WAN link connecting the home PC network to the Internet. Three Internet servers provide different services to the client PCs. Near the top of the figure are two boxes that do not represent physical components: Applications and Profiles. The Applications node contains data about the applications used in the network, such as Web browsing. More specifically, traffic is associated with each application, so there is a difference between “light Web browsing” and “heavy Web browsing.” Internal file service and print service traffic are not shown; these would be too light to make a difference in performance because the Internet WAN connection is the weak link in this network. In the Profiles icon, different applications are associated with different PCs.
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The complete topology is laid out and the attributes for all the objects are pre-configured except the link data rate...