E-Lab 7.2.9 - Load Balancing Across Multiple Paths
Load balance across multiple paths and observe load balancing.
Router Abu_Dhabi and the physical network topology have already been configured.
Step 1
Enter into global configuration mode.
Step 2
Give this router a hostname of Muscat.
Step 3.1
Enter into interface configuration mode on serial 0/0.
Step 3.2
Give this interface an IP address of 192.168.13.1 255.255.255.0.
Step 3.3
Set the clockrate to be 56000.
Step 3.4
Activate this interface.
Step 3.5
Configure the router to load balance on a per-packet basis.
Both serial interfaces must use process switching.
Process switching forces the router to look in the routing table for the destination network of each routed packet.
In contrast, fast-switching (default) stores the initial table lookup in a high-speed cache and use the info to route packets to the same destination.
To accomplish this step, disable route-cacheing.
Step 3.6
Exit into global configuration mode.
Step 4.1
Enter into interface configuration mode on serial 0/1.
Step 4.2
Give this interface an IP address of 192.168.15.1 255.255.255.0.
Step 4.3
Activate this interface.
Step 4.4
Disable route-cacheing on this interface also.
Step 4.5
Exit into global configuration mode.
Step 5.1
Enter into interface configuration mode for Fastethernet 0/0.
Step 5.2
Give this interface an IP address of 192.168.14.1 255.255.255.0.
Step 5.3
Activate this interface.
Step 6.1
Enter into router configuration mode for RIP.
Step 6.2
Add the network 192.168.13.0 into the routing process.
Step 6.3
Add the network 192.168.14.0 into the routing process.
Step 6.4
Add the network 192.168.15.0 into the routing process.
Step 6.5
Exit into privileged EXEC mode with end.
Step 7.1
Verify that fast switching is disabled by using the show ip interface command.
Step 7.2
Set the router to debug ip packet to view their routes.
Step 8
Issue a ping to WorkstationB at 192.168.16.2 (from WorkstationA).
Step 9
Now examine the debugging information just received.
What is the evidence of load balancing in the output?
Now enable fast switching again.
Start by entering into global configuration mode.
Step 10.1
Enter into interface configuration mode for serial 0/0.
Step 10.2
Enable fast switching by using the command ip route-cache.
Step 10.3
Exit into global configuration mode.
Step 11.1
Enter into interface configuration mode for serial 0/1.
Step 11.2
Enable fast switching by using the command ip route-cache.
Step 11.3
Exit into privileged EXEC mode with end.
Step 12
Verify that fast switching is enabled with show ip interface.
Step 13
Issue a ping to WorkstationB again at 192.168.16.2 (from WorkstationA).
Step 14
The routing table is consulted only once per destination, therefore, packets that are part of a packet train to a specific host will all follow the same path.
Only when a second destination forces another table lookup or when the cached entry expires will the alternate path be used.
Note which serial interface the packet was sent out?
Examine and record part of the debug output.
Which serial interface was the packet sent out?
Stop all debugging with undebug all.