Re: vlans and netbsd-current

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Mon, 09 Jun 2014 03:22:43 +1000
    From:        Darren Reed <darrenr%netbsd.org@localhost>
    Message-ID:  <53949BE3.80303%netbsd.org@localhost>

  | In the first instance, because NetBSD vlan interfaces that have a vlanid
  | cannot exist without a hardware interface underneath them. So if you only
  | have one NIC, say bge0, then every vlan interface must have that under it.

The only points of the vlan interface type is to allow multiple logical
networks on one physical cable.  Without an underlying network, they make
no sense (they're not "virtual lans" in the abstract sense).  But I
don't believe that an actual physical interface name is required to be the 
parent, you should (not that I have tested it on NetBSD) be able to run
vlans over anything that presents a lan type interface (like tap, and
others).

  | To put this another way, if I can plug bge0 and bge1 into the same LAN
  | and use them in whichever way, why can't I plug vlan0 and vlan1 both
  | into the same VLAN?

The former used to make no sense either - but with switches, it allows you
to multiply bandwidth, so supporting it (which used not to be done) now makes
sense.  Multiple vlans on the same vlanif with the same vlanid achieves
nothing.

You cannot give different vlan interface names to different chroots, as
chroot doesn't affect interface naming (all vlans would be in every chroot
environment).   Etc...   There's just no upside.

kre