Re: vlans and netbsd-current

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Mon, Jun 09, 2014 at 02:45:19AM +1000, Darren Reed wrote:
> > In Sun, Jun 08, 2014 at 10:56:50PM +1000, Darren Reed wrote:
> > > 
> > ...
> > >         inet6 fe80::203:baff:fe34:a1f5%cas0 prefixlen 64 scopeid 0x6
> > > vlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> > >         vlan: 200 parent: cas0
> > >         address: 00:03:ba:34:a1:f5
> > > ...
> > > vlan1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> > >         vlan: 201 parent: cas0
> > >         address: 00:03:ba:34:a1:f5
> > 
> > > I've got three interfaces with the same MAC address!
> >
> > This is correct.  It is an error to connect two vlan interfaces on the
> > same underlying physical network to the same layer 2 network.  So the
> > MAC address being the same can't cause problems.
> > ...
> > Note that the
> > pathological case where you configure two vlan interfaces on the same
> > physical interface with the _same_ vlanif, simulating dual-attach to the
> > same physical LAN in the SunOS 4 case (which is where that was problematic)
> > is also insane -- it's easy enough to work out why.
> 
> I think you're wrong here.
> 
> For example, what if I were to create two chroot environments on my
> NetBSD box and I wanted to use a dedicated NIC and IP address for each?
> And if I want each NIC to be its own vlan interface?
> 
> Or what if I want to do virtual networking inside of NetBSD and create
> a vwire between two vlan interfaces?
> 
> Or connect both vlan interfaces to a virtual switch inside the kernel?

Why do any of these require stacking two instances of vlan, with the same
vlanif, on the same physical interface?

Thor