I have demand-dial PPP working on a small NetBSD-1.2 386sx box and
(other than SILO overflows) it works really well.

However, I'm dialing into a Livingston Portmaster router and I
really want to be able to have the PM dial me on demand as well as
me dial the PM as I do now.  This would be functionally like two
Ascend ISDN routers dialing each other on demand, except much slower ;-)
There's only one modem, so two links can't be active simultaneously.

But I see trouble ahead: pppd "parks" with IP interfaces open and
IP numbers assigned.  If that interface has timed-out and lost carrier,
pppd is still active.  If the PM dialed up and invoked a pppd
through the login process, all hell would break loose, would it
not?

If anyone has thought about this or implemented it, please elucidate.

Thanks!

-bmw