logical interfaces are for example the loopback interface and the null interface.
The null interface is always there. if you want to drop a route you can send all packets the delta quadrant with.
ip route 192.168.1.0 255.255.255.0 null0
if you want to have an interface that is always up, maybe for your ospf routing process to stay alive you can use something like:
int loopback 0
ip add 192.168.1.1 255.255.255.0
You don’t have to use the „no shutdown“ command.
This interface will always stay tuned. 🙂