[ovs-discuss] When a controller is plugged in vlans stop working: normal?

[Pasquale Dir]

Sorry, maybe I explained myself bad.
By using gre tunnels I created an overlay network between the openvswitches
which I also call "internal" because, except for specific events, traffic
which travels on this network will just be for hosts belonging to it.

So you say problem could be a loop?I am sure to have enabled the stp on
each switch, anyway I'll have a further look....but still I can't explain
why it just happens when eth0 is inserted as a switch port...

Thanks anyway for help and sorry if I am not being very clear


2014-05-05 23:45 GMT+02:00 Ben Pfaff <blp at nicira.com>:

> On Mon, May 05, 2014 at 11:22:46PM +0200, Pasquale Dir wrote:
> > Problem is that for my project I need openvswitches which can be used to
> > make communicate internal hosts with external ones, if specific events
> > occur.
> >
> > So my idea was the following: a generic openvswitch would have been like
> > -br0
> > ---eth0
> > ---gre0 tag2
> >
> > If I would have needed to share some resource to the external world I'd
> > just put an openflow rule on the specific openvswitch telling it to
> output
> > specific packets from gre0 port (internal) to the eth0 port (external).
> >
> > Hosts who attach to an openvswitch throught tagged ports are indeed part
> of
> > an internal network so it is just right that they can communicate JUST
> > between each other by gre tunnels...but if eth0 is connected to the
> > openvswitch too, these hosts stop communicating.
>
> Presumably, you're causing a loop.
>
> > I though that, as openvswitch is executed as a software process, it would
> > have used linux network stack anyway to allow gre tunnel
> > communication...but it seems it doesn't.
>
> It does.
>
> > It will do it with this configuration:
> > -bro
> > ---gre0 tag2
> > -eth0
> >
> > but it is not ok to me, as I would miss a way to output some internal gre
> > traffic to eth0, as it isn't connected to the switch and thus I could not
> > make any openflow rule.
>
> "Internal" GRE traffic?  What's that?  GRE is used to communicate over
> an external network.  For internal communication (within a host), you
> don't need GRE.
>
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