Net360 Instructions

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  • Topic: Packet delay variation, ZOOM
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  • Published : September 15, 2012
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NETW320: Converged Networks with Lab
Lab #6 Title: Codec Selection for Campus Network – Part 2. Procedure
Start OPNET IT Guru.

Open the scenario

1. Select File/Open.

2. Select Computer or My Computer (depending on which O/S you have).

3. On your f: drive, open the op_models folder and then the NETW320 folder.

4. Open Lab3_LANCodec.project.

5. Click on Lab3_LANCodec.prj or Lab3_LANCodec (again, depending on what O/S you have).

6. Click Open. The project should open.

7. Choose Scenarios > Switch Scenarios > LANCodec

Configure the Simulation Run

1. We now are ready to configure the simulation. Select the Configuration/Run [pic] tab from the tool bar. After clicking on it, the following screen will open.

[pic]

2. Change Duration to 3 and hour(s) to minute(s) (if it’s not already). Then, expand the Traffic entry. [pic]

3. Scroll down to the Traffic Scaling Factor and Traffic Scaling Mode options.

[pic]

4. Change the value of the Traffic Scaling Factor from 1.0 to 0.2 by selecting Edit and typing in the new value. Change the value of the Traffic Scaling Mode from Background Traffic to All Traffic (if it’s not already).

[pic]

5. Changing these attributes will allow the simulation to run faster. Click Apply and then Cancel to close the Configure/Run DES window.

6. At this point, Save your scenario.

7. Before we duplicate the scenarios, now would be a good time to run the first simulation to ensure that we have all of the configurations made correctly. Once we copy them over to the G729 and G723.1 scenarios, if something is configured incorrectly, that mistake will be transferred over.

8. From the tool bar, select Scenarios -> Manage Scenarios. The following menu will appear.

[pic]

9. Under the Results column for the first Scenario, LANCodec, change uncollected to and click OK. While the sim is running, you should see this screen. [pic]

10. It may take a couple of minutes for the simulation to run because we are asking the simulation to do a lot of calculations and graphs. When the sim is complete (the Close button will light), click the Close button. We are now ready to look at the results.

11. From the tool bar, select DES > Results > View Results. The Results Browser will appear. [pic]

12. Expand “Global Statistics” and select the following: Expand Select
DB Query Response Time (sec)
E-mail Download Response Time (sec)
Voice Packet End-to-End Delay (sec)
[pic]

13. Then, change AS IS to Time Average using the dropdown arrow and click the Show button. The following panel will appear.

[pic]

14. Your graphs do not have to match exactly, but they should be very similar. If they are not, recheck your work before continuing. Close out of the graphs by selecting the X in the top right-hand side of the window and Delete the panel. We can always look at the graph again later if we choose to do so. Close out of the Results Browser.

Duplicating the Scenarios

1. Now we will create two more scenarios. In the second one, we will change the Codec from G.711 to G.729, and in the third one, we will change the Codec to G.723.1. Then, we will compare the results for all three scenarios simultaneously to analyze the behavior of the network traffic.

2. Select Scenarios> Duplicate Scenarios option from the menu bar. The Enter Name window will appear, adding 1 to the current scenario name. Delete the 1 and add _G729 to make the new scenario name, as below.

[pic]

3. The new screen will automatically assign the name of LANCodec_G729 to the new scenario. Click OK.

4. Highlight the Application Config node by left-clicking on it and then right-click on the node and select Edit Attributes from the menu. The following screen will appear. Expand the Application Definitions tree....
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