I have a site where once ISDN comes up, OSPF stops sending hellos and the adjacency stays up after ISDN drops. Looking into this I read about ospf demand circuit.
I verified this by running 'show ip ospf interface dialer' and saw the line "Run as demand circuit'.
Neither ISDN site has the command in it's running config, yet all the examples I find show it must be explicitly configured.
Is this the default behavior of OSPF over ISDN now? If so, when did it become default?