In a previous lesson I explained the OSPF Non-Broadcast Network Type. Now it’s time for the broadcast network type. If you understand non-broadcast then this one is easy. It’s the EXACT same thing except we don’t have to configure neighbors. OSPF will use multicast and discover OSPF neighbors automatically. The broadcast network type is the default for Ethernet interfaces.
This is the topology that we’ll use:
Hub(config)#interface serial 0/0
Hub(config-if)#ip address 192.168.123.1 255.255.255.0
Hub(config-if)#encapsulation frame-relay
Hub(config-if)#ip ospf network broadcast
Hub(config-if)#exit
Hub(config)#router ospf 1
Hub(config-router)#network 192.168.123.0 0.0.0.255 area 0
Here is the configuration of the Hub router. You can see I used the ip ospf network broadcast command to change the OSPF network type. Here are the spoke routers: