Re: CVS commit: src/sys/net

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

>> (Though, at least in my experience, NetBSD's "bridge" interfaces are
>> more like switches than bridges.)
> I am not sure how you draw the line between switch and bridge.

It's admittedly a somewhat fuzzy distinction - but then, `bridge' is a
somewhat fuzzy term too.

As I was using it in the double-quoted text above, a bridge is much
dumber, on the order of a hub or a media converter, just echoing out
what it receives in.  A switch has more smarts - it knows enough about
packet formats to pick out source and destination addresses, learn what
addresses occur on which ports, and avoid sending unicast packets to
pointless ports.  It also might speak a few protocols, such as spanning
tree, in its own right.

> I agree that "bridge0" being a "network interface" is not entirely
> right.  I see it as close enough that using config ioctls is sensible
> and therefore it seems like a software writing optimization, compared
> to creating a first-class switch type.

I'm not sure.  The only parts of the "network interface" abstraction I
see bridges as really using are creation and destruction, naming
(including ifconfig -l), and IFF_UP/~IFF_UP.  I'm not sure whether I
think that's justification enough for dragging along the rest of the
network interface baggage - perhaps I just haven't looked closely
enough at the bridge implementation.

Maybe it would help if bridges rejected all attempts to configure
addresses on them?

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