Configuration of OSPF
Initialize the Network:
- The Object Palette dialog box should now be on top of your project workspace. If it is not there, open it by clicking on a image near by. Select the routers item from the pull-down menu on the object palette.
- Add to the project workspace eight routers of type slip8_gtwy. To add an object from a palette, click its icon in the object palette ⇒ Move your mouse to the workspace and click to place the object ⇒ You can keep on left-clicking to create additional objects. Right-click when you are finished placing the last object.
- Switch the palette configuration so it contains the internet_toolbox. Use bidirectional PPP_DS3 links to connect the routers. Rename the routers as shown below.
- Close the Object Palette and then save your project.
- We need to assign link costs to match the following graph:
- Like many popular commercial routers, OPNET router models support a parameter called a reference bandwidth to calculate the actual cost, as follows:
Cost = (Reference bandwidth) / (Link bandwidth)
where the default value of the reference bandwidth is 1,000,000 Kbps.
- For example, to assign a cost of 5 to a link, assign a bandwidth of 200,000 Kbps to that link. Note that this is not the actual bandwidth of the link in the sense of transmission speed, but merely a parameter used to configure link costs.
- To assign the costs to the links of our network, do the following:
- Select all links in your network that correspond to the links with a cost of 5 in the above graph by shift-clicking on them.
- Select the Protocols menu ⇒ IP ⇒ Routing ⇒ Configure Interface Metric Information.
- Assign 200000 to the Bandwidth (Kbps) field ⇒ Check the Interfaces across selected links radio button, as shown ⇒ Click OK.
- Repeat step 4 for all links with a cost of 10 but assign 100,000 Kbps to the Bandwidth (Kbps) field.
- Repeat step 4 for all links with a cost of 20 but assign 50,000 Kbps to the Bandwidth (Kbps) field.
- Save your project.
- Select both RouterA and RouterC by shift-clicking on them.
- Select the Protocols menu ⇒ IP ⇒ Demands ⇒ Create Traffic Demands ⇒ Check the From RouterA radio button as shown ⇒ Keep the color as blue ⇒ Click Create. Now you should see a blue-dotted line representing the traffic demand between RouterA and RouterC.
- Select both RouterB and RouterH by shift-clicking on them.
- Select the Protocols menu ⇒ IP ⇒ Demands ⇒ Create Traffic Demands ⇒ Check the From RouterB radio button ⇒ Change the color to red ⇒ Click OK ⇒ Click Create.
Now you can see the lines representing the traffic demands as shown.
- To hide these lines: Select the View menu ⇒ Select Demand Objects ⇒ Select Hide All.
- Save your project.
- Select the Protocols menu ⇒ IP ⇒ Routing ⇒ Configure Routing Protocols.
- Check the OSPF check box ⇒ Uncheck the RIP check box ⇒ Uncheck the Visualize Routing Domains check box, as shown:
- Click OK
- Select RouterA and RouterB only ⇒ Select the Protocols menu ⇒ IP ⇒ Routing ⇒ Select Export Routing Table for Selected Routers ⇒ Click OK on the Status Confirm dialog box.
- Select the Protocols menu ⇒ IP ⇒ Addressing ⇒ Select Auto-Assign IP Addresses.
- Save your project.
- Click on and the Configure Simulation window should appear.
- Set the duration to be 10.0 minutes.
- Click OK and then Save your project.
In the network we just created, all routers belong to one level of hierarchy (i.e., one area). Also, we didn't enforce load balancing for any routes. Two new scenarios will be created. The first new scenario will define two new areas in addition to the backbone area. The second one will be configured to balance the load for the traffic demands between RouterB and RouterH.
The Areas Scenario:
- Select Duplicate Scenario from the Scenarios menu and give it the name Areas ⇒ Click OK.
- Area 0.0.0.1:
- Select the three links that connect RouterA, RouterB, and RouterC by shift- clicking on them ⇒ Select the Protocols menu ⇒ OSPF ⇒ Configure Areas ⇒ Assign the value 0.0.0.1 to the Area Identifier, as shown ⇒ Click OK.
- Right-click on RouterC ⇒ Edit Attributes ⇒ Expand the OSPF Parameters hierarchy ⇒ Expand the Loopback Interfaces hierarchy ⇒ Expand the row0 hierarchy ⇒ Assign 0.0.0.1 to the value of the Area ID attribute ⇒ Click OK.
- Area 0.0.0.2:
- Click somewhere in the project workspace to disable the selected links and then repeat step 2-i for the three links that connect RouterF, RouterG, and RouterH but assign the value 0.0.0.2 to their Area Identifier.
- To visualize the areas we just created, select the Protocols menu ⇒ OSPF ⇒ Visualize Areas ⇒ Click OK. The network should look like the following one with different colors assigned to each area (you may get different colors though).
The Balanced Scenario:
- Under the Scenarios menu, Switch to Scenario ⇒ Select No_Areas
- Select Duplicate Scenario from the Scenarios menu, and give it the name Balanced ⇒ Click OK.
- In the new scenario, select both RouterB and RouterH by shift-clicking on them.
- Select the Protocols menu ⇒ IP ⇒ Routing ⇒ Configure Load Balancing Options ⇒ Make sure that the option is Packet-Based and the radio button Selected Routers is selected as shown ⇒ Click OK.
- Save your Project
To run the simulation for the three scenarios simultaneously:
- Go to the Scenarios menu ⇒ Select Manage Scenarios.
- Click on the row of each scenario and click the Collect Results button. This should change the values under the Results column to as shown.
- Click OK to run the three simulations. Depending on the speed of your processor, this may take several seconds to complete.
- After the three simulation runs complete, one for each scenario, click Close and then save your project.
The No_Areas Scenario:
- Go back to the No_Areas scenario.
- To display the route for the traffic demand between RouterA and RouterC: Select the Protocols menu ⇒ IP ⇒ Demands ⇒ Display Routes for Configured Demands ⇒ Expand the hierarchies as shown and select RouterA Æ RouterC ⇒ Go to the Display column and pick Yes ⇒ Click Close.
- The resulting route will appear on the network as shown:
- Repeat step 2 to show the route for the traffic demand between RouterB and RouterH. The route is as shown below. (Note: Depending on the order in which you created the network topology, the other "equal-cost" path can be used, that is, the RouterB-RouterA-RouterD-RouterF-RouterH path).