Subject: Re: [cube@cubidou.net: Re: Moving ethfoo in the main tree]
To: Thor Lancelot Simon <tls@rek.tjls.com>
From: Quentin Garnier <cube@cubidou.net>
List: tech-kern
Date: 12/13/2004 20:12:55
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On Mon, Dec 13, 2004 at 12:34:47PM -0500, Thor Lancelot Simon wrote:
> On Mon, Dec 13, 2004 at 12:11:38PM +0100, Quentin Garnier wrote:
> >=20
> > qemu can work with two network modes.  The internal one (user-mode
> > network stack) is rather kludgy, as it is limited to what a user can
> > do, and only to some extent.
> >=20
> > The tun/tap mode uses a device such as ethfoo which emulates a complete
> > Ethernet segment between the host.  It makes it appear as a separate
> > computer which, for example, would be linked to the host with a cross-
> > over cable.
> >=20
> > While I haven't tried it, I don't see anything that could prevent two
> > instances of qemu from doing network communication that way, the host
> > will server as a router in that situation.
>=20
> Hm.  That's not quite what's wanted, in a lot of applications.  The
> VMware virtual ethernet device, for example, acts like a hub or
> switch -- it puts all the endpoints on the _same_ virtual segment.
>=20
> I suppose it would be possible to do something similar by combining
> tap with bridge, but that's a bit messy.

I don't find it messy, as it is quite clear what everything does that
way, and keeps ethfoo simpler (at least for what it's useful for).  But
adding switch functionality to ethfoo is definitely interesting, e.g.
because that way a new interface could be automatically added to the
switch.

However, this has to be properly done, and can be done later.

--=20
Quentin Garnier - cube@cubidou.net - cube@NetBSD.org
"Commala-come-five! / Even when the shadows rise!
To see the world and walk the world / Makes ya glad to be alive."
Susannah's Song, The Dark Tower VI, Stephen King, 2004.

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