Not 100% sure about your question, but here it goes.
A non routable network is, a network that is not “visible” in the Internet.
These are private networks; those which we use internally in our home and company intranets.
These are reserved IP address scopes that no router routes to the internet.
They provide a little extra security layer to the “internal” side of a network.
Ip addresses reserved for private networks:
10.0.0.0 – 10.255.255.255
172.16.0.0 – 172.31.255.255
192.168.0.0 – 192.168.255.255
If you want to leaen alittle more about this, you can check the RFC 1597.