How do I create a tunnel interface on a Cisco Router ?
Below shows you the steps on how to create a tunnel interface on a Cisco router with the inclusion of OSPF based commands so that Dynamic routing updates can be sent across the link to the remote peer.
ip address [IP] [Mask]
ip ospf network point-to-point
ip ospf mtu-ignore
tunnel source FastEthernet0/0
tunnel destination [remote peer ip]