[ovs-dev] [PATCH] ovs-vsctl: Allow "fake bridges" to be created for VLAN 0.

Chris Wright chrisw at sous-sol.org
Fri Mar 16 16:39:07 PDT 2012


* Ben Pfaff (blp at nicira.com) wrote:
> On Fri, Mar 16, 2012 at 04:30:17PM -0700, Chris Wright wrote:
> > * Ben Pfaff (blp at nicira.com) wrote:
> > > On Fri, Mar 16, 2012 at 04:03:23PM -0700, Jesse Gross wrote:
> > > > On Fri, Mar 16, 2012 at 1:13 PM, Ben Pfaff <blp at nicira.com> wrote:
> > > > > diff --git a/utilities/ovs-vsctl.8.in b/utilities/ovs-vsctl.8.in
> > > > > index 0d858a1..57f76d5 100644
> > > > > --- a/utilities/ovs-vsctl.8.in
> > > > > +++ b/utilities/ovs-vsctl.8.in
> > > > > @@ -69,7 +69,8 @@ When such a ``fake bridge'' is active, \fBovs\-vsctl\fR will treat it
> > > > >  much like a bridge separate from its ``parent bridge,'' but the actual
> > > > >  implementation in Open vSwitch uses only a single bridge, with ports on
> > > > >  the fake bridge assigned the implicit VLAN of the fake bridge of which
> > > > > -they are members.
> > > > > +they are members.  (A fake bridge for VLAN 0 receives packets that
> > > > > +have no 802.1Q tag or a tag with VLAN 0.)
> > > > 
> > > > How do we handle this situation?  The meaning of vlan 0 can be
> > > > ambiguous - some drivers consider it to mean the same thing as
> > > > untagged and some consider it to be a vlan just like any other.  Do we
> > > > actually do anything to deal with this?
> > > 
> > > Not certain what you're asking.  This paragraph describes OVS
> > > behavior, which should be driver-independent modulo VLAN bugs (that we
> > > have several ways to work around).  A "fake bridge" is just
> > > implemented as OVS ports with tag=0.
> > 
> > Will it isolate traffic?  I don't believe that would be accurate.
> 
> Traffic on a fake bridge for VLAN 0 (i.e. ports with tag=0) is
> isolated from traffic on fake bridges for other VLANs (i.e. ports with
> tag!=0).  Neither kind of fake bridge (or port) isolates traffic from
> that on trunk ports (e.g. ports with tag=[]).

OK, that's what I meant (isolate from the tag=[]).  Sounds good.

thanks,
-chris



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