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Simulating Computer Networks with Opnet

A Simple Tutorial

Objectives1) This tutorial focuses on the use of Opnet’s Project

Editor2) The Project Editor will allow you to quickly create,

simulate, and analyze the performance of a computer network

3) By the end of this tutorial, you should be able to1) Build a network quickly2) Collect statistics about the network’s performance3) Analyze these statistics

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Objectives

1) In this tutorial1) We will build a small network2) Choose statistics to collect3) Run a simulation4) Analyze the results

Projects and Scenarios

When creating a new network model, you must first create a new project and scenario.

Project:A project is a group of related scenarios that each explore a different aspect of the network design. Projects can contain multiple scenarios.Once you have created a new project, you can use the Startup Wizard to set up a new scenario

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Creating a Project

From the File menu, choose New Select Project and click OK

Name the project <Sample_your initials>and the scenario first_floor. (Include you initials in the project name to distinguish it from other students.) Click OK

Click Next in the Startup Wizard

Scenario

The scenario Wizard dialog box is shown

Box Value Initial Topology Create Empty Scenario Click Next Network Scale Office Click NextSpecify Size 100 m x 100 m Click NextModel Family Ethernet Click NextReview Check values Click OK

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Creating Network Topologies

There are three ways to create network topologies1) Importing the topology2) Placing each individual node from the object palette into the workspace3) Creating a new network topology is by using the Rapid Configuration feature.

Creating Network Topologies

Rapid Configuration FeatureRapid Configuration allows you to select a network topology, the types of nodes within the network, and the links connecting the nodes.

To create the first floor network using Rapid Configuration:

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Creating Network Topologies

Rapid Configuration Feature1) From the Topology menu, choose the Rapid Configuration menu item2) Select Star from the list of available configurations, then click OK…..

Creating Network TopologiesRapid Configuration Feature

Now that the network topology has been selected, you must specify the nodes and links to use to construct the network. Models follow this naming scheme:

Center Node Model ethernet_16_hubPeriphery Node Model ethernet_wkstnLink Model 10BaseTNumber 5Center X = 25, Y = 25Radius 20

Click OK

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It should look like this

Adding Components

Now that the general network topology has been constructed, you need to add a server. You can now use the second method of creating network objects, that is, dragging them from the object palette into the workspace.

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Adding Components

1) If it is not already open, open the object palette by clicking on the Object Palette action button (first button on the left)

2) Find the ethernet_server object in the palette and drag it into the workspace

3) You don’t need additional copies of this model, so right-click to turn off node creation

Adding Components

You also need to connect the server to the start network.1) Find the 10BaseT link object in the palette, click on it and drag it to the workspace2) Click on the server object, then click on the switch object in the center of the star. A link is drawn, connecting the two objects.3) Right-click to turn off link creation.

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Adding ComponentsFinally, you need to add configuration objects to specify the application traffic that will exist on the network1) Find the Application Config object in the palette and drag it into the workspace2) Right-click to indicate you are finished placing this kind of object3) Find the Profile Config object in the palette and drag it into the workspace4) Close the object palette

It should look something like this:

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Editing Attributes

1) You can change the properties of objects such as hubs, switches, work station, etc. by editing the attributes

2) Right click on the object you want to edit3) Choose Edit attributes

Adding Traffic to the Network

In order to add traffic in the network editthe following objects:

1) Application Definition2) Set the application definition attribute toDefault

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Adding Traffic

1) Edit the Profile Configuration2) Edit the Profile Configuration in the new

window3) Put number 2 in rows4) Set the values as shown in the following

slide

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Profile Configuration Cont…

1) Click on applications for each Profilename, and choose edit

2) Enter the values for SoftwareDevelopment as shown in the followingslide

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Profile Configuration Cont..

Now do the same for profile telecom

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Adding Traffic

1) Now that you are done with Application and Profile, next you need to add traffic in each work station1) Select node_12) Edit attribute3) Do this for all the workstations

2) It should look like the picture in the next page

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Adding Traffic

Then enter 2 for the number of row. It should be on the the bottom left side. Then click on each Profile name and choose Software Development for row 1 and Telecom row row 2. It should look similar to the next page. Hit ok for everything.

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Connect the Server

You also need to make it connected with the server also. Right click on the server then choose edit attributes. On the the attribute field look for Application: Supported Service and click “ALL” for the value field. It should look like this

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Statistics

1) Now that you added the traffic, you are ready to collect some statistics

2) There are two ways to collect statistics1) You can collect statistics from individual nodes in your network (object statistics)2) From the entire network as a whole (global statistics)

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Server Statistics

1) To collect statistics related to the server’s load:1) Right-click on the server node and select Choose Individual Statistics from the server’s Object pop-up menu2) Click the plus sign next to Ethernet in the Choose Results dialog box.

Server Statistics

1) Click the check box next to Load (bits/sec) to turn collection on for that statistic

2) Click OK to dismiss the dialog box

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Network Statistics

1) To collect statistics related to the Ethernet Hub:1) Right-click on the hub node and select Choose Individual Statistics from the hub’s Object pop-up menu2) Click the plus sign next to Node Statistic in the Choose Results dialog box3) Then click the plus sign next to Ethernet in the Choose Results dialog box

Network Statistics

1) Click the check box next to Collision count and Utilization2) Click OK to dismiss the dialog box

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It should look like this

Global Statistics

1) Global statistics can be used to gather information about the network as a whole. For example, you can find out the delay for the entire network by collecting the global Delay statistic:1) Right-click in the project workspace and select Choose Individual Statistics from the Workspace pop-up menu2) Click the plus sign next to Global Statistics in the Choose Results dialog box

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Global Statistics3) Click the plus sign next to Ethernet4) Check the box next to Delay (sec) to turn on collection5) Click OK to dismiss the Choose Results dialog box Hit Save to save the projectNote: If you can’t save your project, go to Edit/Preferences, find the model_dirs row and click on the Value field. In the new pop-up window, make sure the first directory of the list is a place where the tool can save your project (You can create a new directory on C:\your_nameand put that directory as the first entry in the list)

It should look like this

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Run the Simulation

Now that you have specified the network, traffic, statistics to collect and saved the project, you are ready to run your simulation. To run a simulation:

1) From the Simulation menu, choose Configure Simulation. Note: You can also open the Configure Simulation dialog box by clicking on the Configure Simulation action button.

2) Type 10 min in the Duration

Run the Simulation

3) Click the Run button to begin the simulation. While the simulation runs, a window appears showing the simulation’s progress. The simulation takes 1 minute to run on a 200MHz Pentium. Your time will vary depending on your computer. After 1,000,000 events, the Simulation Sequence dialog box shows an estimated time to completion and a progress bar

4) When the simulation is finished, click the Close button in the Simulation Sequence dialog box

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Simulation Results

Once your simulation has finished executing, you will want to see the information collected for each statistic

You can view results graphically in the Project Editor by selecting View Results from the Workspace pop-up menu.

View ResultsTo view the server Ethernet load for the simulation:

1) Right-click on the server node choose View Results from the server’s Object pop-up menu. The node’s View Results dialog box opens.2) Click on the arrow next to Ethernet under Office network.3) Click on the box next to Load (bits/sec) to indicate that you want to view that result.4) Click the Show button in the View Results dialog box. The graph of the server load appears in the Project Editor

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View ResultsTo view the Ethernet Hub Collision count and Utilization:

1) Right-click on the Ethernet Hub choose View Results from the server’s Object pop-up menu. The node’s View Results dialog box opens2) Click on the arrow next to Ethernet under Office network3) Click on the box next to collision count and utilization to indicate that you want to view that result4) Select average ant then click the Show button in the View Results dialog box. The graph should look this:

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View ResultsWhen you are finished viewing the Ethernet Hub

graph, close this dialog box and the View Results dialog box. You also should look at the Global Ethernet Delay on the network. To view this statistic:

1) Right-click in the workspace, then select View Results from the pop-up menu

2) Check the box next to Global Statistics, Ethernet, Delay, select average then click the Show button to view the average delay of the packets on the Ethernet network as a whole

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Animation

View animation:To view animation, click on Simulation and select Record Animation For Subnet. You have to do this before you run the program

Animation

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Animation

Then run the simulation. After the simulation finishes, click on Result and choose Play Animation.

Animation

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Debugging

1) A good debugging tool is the Simulation Log. You can check for warnings and errors

2) Click on Result3) Then Click on Open Simulation Log