if_flags usage etc.

[sthaug at nethelp.no]

> We should probably better document the interface "interface". if we are 
> going to (as Sam suggests)
> do some cleanups we might as well consider what other changes should be 
> put in at the same time.

A couple of other suggestions:

- For software routers (quagga, zebra etc.) it would be very nice to
have "link up" / "link down" notifications to the routing process(es).

- One feature sorely missed (which I use a lot in my daily work with
hardware based routers) is the ability to associate a "description"
field with each interface.  Note that this should be available both
for physical interfaces (Ethernet etc.) and for logical interfaces
(e.g. vlan).

Steinar Haug, Nethelp consulting, sthaug at nethelp.no