Lab 6.3.2 Configuring OSPF Summarization
Step 1: Connect the equipment
- Connect Router 1 to Routers 2 and 3 with serial cables. Connect Router 2 to Router 3 with a serial cable.
- Connect the Router 2 Fa0/0 interface to the Switch 2 Fa0/1 interface using a straight-through cable.
- Connect the Router 3 Fa0/0 interface to the Switch 3 Fa0/1 interface using a straight-through cable.
- Connect Host 2 to Switch 2 and Host 3 to Switch 3 to the Fa0/2 interface using straight-through cables.
- Connect Host 1 to the Router 1 Fa0/0 interface using a crossover cable.
- Connect a PC with a console cable to perform configurations on the routers and switches.
Step 2: Perform basic configurations on the routers
- Establish a console session with Router 1 and configure hostname, passwords, and interfaces as shown in the addressing table. Save the configuration.
- Establish a console session with Router 2. Configure hostname, passwords, and interfaces according to the addressing table. Save the configuration.
- Establish a console session with Router 3. Configure hostname, passwords, and interfaces according to the addressing table. Save the configuration.
Step 3: Perform basic configurations on the switches
- Establish a console session with Switch 2 and configure hostname and passwords according to the addressing table. Save the configuration.
- Perform a similar configuration on Switch 3, configuring the hostname and passwords as described for SW 2. Save the configuration.
Step 4: Configure the hosts with the proper IP address, subnet mask, and default gateway
- Configure each host with the proper IP address, subnet mask, and default gateway for the network on which it resides. Host 1 should be assigned the address 209.165.201.1/24. Host 2 and Host 3 should be assigned IP addresses in the 192.168.10.0/28 and 192.168.10.32/28 networks respectively. All three PCs use the Fa0/0 interface of their attached router as their default gateway.
- Each workstation should be able to ping the attached router. If the ping is not successful, troubleshoot as necessary. Check and verify that the workstation has been assigned the correct IP address and default gateway.
Step 5: Configure OSPF routing with default summarization
- On Border, configure OSPF as the routing protocol with a process ID of 1 and advertise the appropriate networks.
- Perform a similar configuration on R2, using the same process ID and advertising the appropriate networks. Remember to advertise the FastEthernet interface.
- On R3, perform a similar configuration, using the same process ID and advertising the appropriate networks.
Step 6: Configure and redistribute a default route for Internet access
- From the Border router to Host 1, the host simulating the Internet, create a static route to network 0.0.0.0 0.0.0.0, using the ip route command and the next hop interface. This will forward any unknown-destination address traffic to the PC simulating the Internet by setting a gateway of last resort on the Border router.
- Border will advertise this route to the other routers if this command is added to its OSPF configuration.
Border(config)#router ospf 1
Border(config-router)#default-information originate
Step 7: Verify the routing configuration
- View the routing table on Border.
- View the routing tables on R2 and R3.
How is the pathway for Internet traffic provided in their routing tables? There is a gateway of last resort leading to R3, and the default route shows up as a distributed OSPF route.
Step 8: Verify connectivity
- Simulate sending traffic to the Internet by pinging from the host PCs to 209.165.201.1.
Were the pings successful? __________ Yes.
Verify that hosts within the subnetted network can reach each other by pinging between Host 1 and Host 2.
Were the pings successful? __________ Yes.
Step 9: Configure OSPF summarization
- Compute a summary route for the corporate subnetworks. The networks have been assigned contiguously:
- Configure the summary route in router configuration mode, starting with area 0 range followed by the summary route and its mask.
Step 10: Recheck routing tables to verify the summarization
View the effects of summarization using the following commands: Think about your answers to the previous questions. What advantage do you see in using summarization in this network?
Jawaban : This makes the job of the Border router simpler and easier, as it can represent the whole network with one route. The ISP does not care about individual subnets; its job is simply to provide Internet access to the area. Convergence will be improved, as Border will not have to issue updates on every problem on every subnet.
Step 11: Reflection
List three effects of using summarization within an OSPF area?
Jawaban: smaller routing table, lower memory and processor requirements, fewer lookups needed.
