[systemd-devel] Systemd-networkd, default route and multiple interfaces

[Lennart Poettering]

On Wed, 04.06.14 00:29, Mantas Mikulėnas (grawity at gmail.com) wrote:

> 
> On Tue, Jun 3, 2014 at 9:58 PM, Lennart Poettering
> <lennart at poettering.net> wrote:
> >
> > On Mon, 02.06.14 21:02, Tom Gundersen (teg at jklm.no) wrote:
> >
> > > On Mon, Jun 2, 2014 at 8:47 PM, Reventlov
> > > <contact+systemd+ml at volcanis.me> wrote:
> > > > Since network files are applied to links whenever the links
> > > > appear, how do systemd manage the "disappearance" of a default route ?
> > >
> > > You can have several default routes, so we just configure them all and
> > > let the kernel handle it for us. We probably should improve the config
> > > options to make it possible to override the priority of the routes.
> >
> > Windows initializes the route metric value for each route from the
> > "speed" of the interface. If there are multiple links and for one we
> > know it's a gigabit ethernet link, and the other is a 54mbit wlan link,
> > then the former would automatically get preference... it's a bit black
> > magic, but kinda cool black magic i think...
> >
> > that said, i am not sure we even have a sane API to determine the speed
> > of links... maybe ethtool reports it at least for wired ethernet? but
> > for wlan?
> 
> Both `iwconfig <dev>` and `iw <dev> link` report the link speed (one
> using the old wext and the other nl80211, I think?).
> 
> No idea about all the other link types that Linux supports though.

As long as we'd only have to check ethtool for wired ethernet and the
wireless stack for wireless ethernet and can cover 70% of all devices
with that, this sounds like the right thing to do for me...

Lennart

-- 
Lennart Poettering, Red Hat