> while i'll agree that in theory a 16 bit interface number might roll
> over (and what if it did?), in practice i think it won't happen very
> much at all.  i can cause the next assigned interface number to
> increase by repeatedly popping out and pushing back in my pcmcia
> network card, or i can repeatedly create and destroy, for example,
> tun0 (that might roll it over in about ten minutes), but short of
> doing something wrong or trying to roll it over intentionally, i can't
> imagine it would happen naturally.

Lets see, dial out every 10 minutes.
6 per hour
6x24=144 per day
144x365=52560 per year

you soon get to 65536.....

Or have 6 modems used for inward ppp connections....

16 bits aint enough.

32 is probably plenty, 64 is definitely ok (count 10 several GHz for a
century or so)

    David