[ovs-dev] [PATCH ovn 1/3] ovn: Enforce unique tags for container interfaces.

[Thomas Graf]

On 04/07/15 at 10:20am, Russell Bryant wrote:
> IIRC, the proposal was actually quite explicit that the tag is a VLAN
> ID.  It's not a hidden implementation detail because something (not OVN)
> has to set up ovs inside the VM with all of the containers attached and
> have it tag traffic from each container.
> 
> With that said, I'd be happy to see alternatives.  I brought it up
> briefly here:
> 
> http://openvswitch.org/pipermail/dev/2015-March/052584.html

Thinking out loud:

I remember this discussion. One alternative that comes to mind is to
simply push a Geneve header in front of it. It would provide a lot
more flexibility down the road and we could transmit additional metadata
between inner and outer OVS later on.

The OVN model would look the same, except that tag would be a 32 or
64bit Geneve option of known class and type.

The disadvantages to this is obviously increased overhead but given
that these packets never hit the wire and go straight from OVS to OVS.
We could come up with a simplified protocol using a new ethernet type.

eth + gva + ip + tcp