This read-create boolean indicates whether IS-IS should include this interface's address in its LSPs even though the interface is not actually running the IS-IS protocol and forming adjacencies. Setting it true lets an administrator advertise reachability to a stub network, such as a loopback or a LAN with no other IS-IS routers, without paying the overhead of running full IS-IS on that interface. For example, an operator would enable csIsisCircPassiveCircuit on a router's loopback interface so its management IP address is reachable via IS-IS-derived routes across the network.