Lab Simulation C OSPF
A sporting goods manufacturer has decided to network three (3) locations to improve efficiency in inventory control. The routers have been named to reflect the location: Boston, Frankfurt, Lancaster. The necessary networking has been completed at each location, and the routers have been configured with single area OSPF as the routing protocol. The Boston router was recently installed but connectivity is not complete because of incomplete routing tables. Identify and correct any problem you see in the configuration.
Note: The OSPF process must be configured to allow interfaces in specific subnets to participate in the routing process.
Answer: The question mentioned Boston router was not configured correctly or incomplete so we should check this router first. Click on Host B to access the command line interface (CLI) of Boston router.
Boston>enable (type cisco as its password here)
Boston#show running-config
First, remember that the current OSPF Process ID is 2 because we will need it for later configuration. Next notice that in the second “network” command the network and wildcard mask are 192.168.155.0 and 0.0.0.3 which is equivalent to 192.168.155.0 255.255.255.252 in term of subnet mask. Therefore this subnetwork’s range is from 192.168.155.0 to 192.168.155.3 but the ip address of s0/0 interface of Boston router is192.168.155.5 which don’t belong to this range -> this is the reason why OSPF did not recognize s0 interface of Boston router as a part of area 0.
So we need to find a subnetwork that s0 interface belongs to.
IP address of S0 interface: 192.168.155.5/30
Subnet mask: /30 = 1111 1111.1111 1111.1111 1111.1111 1100
Increment: 4
Network address (which IP address of s0 interface belongs to):