[libvirt-users] [ovs-discuss] OpenVswitch with KVM virtual machines

[Ben Pfaff]

On Thu, Jul 12, 2012 at 10:49:14PM +0530, Neha Jatav wrote:
> I am running NOX controller with a python script that prints out the
> destination mac and the source mac for each packet arriving at the now
> controller and then floods it out. So here's what happening:
> 
> With em1 connected, all the packets that arrive at em1 are coming to the
> controller and printing out the details. However, without em1 connected to
> the OVS, when I have the following setup:
>  ____                  ____
> / VM1\______br0_______/ VM3\
> \____/       |        \____/
>              |
>             _|_
>            /VM2\
>            \___/
> 
> VM1 & VM2 are of the same subnet. They can ping each other. The ping
> packets aren't seen at the controller probably because they are in the
> same subnet and they don't need a flow table entry.

That doesn't make sense.  OpenFlow doesn't make any distinction on
this basis.

> VM3 is in a different subnet. So, when I ping from VM1 to VM3 or
> viceversa, they aren't reachable to each other. However, the packets do
> not arrive at the controller at all. Could you suggest me what might
> possibly be wrong.
> 
> This is how the bridge looks:
> 
> $sudo ovs-vsctl br0 show
> Bridge "br0"
> 	Port "vnet1"
> 		Interface "vnet1"
> 	Port "br0"
> 		Interface "br0"
> 		type: internal
> 	Port "vnet0"
> 		Interface "vnet0"
> 	Port "vnet2"
> 		Interface "vnet2"
> 	ovs_version: "1.4.0"

No controller is configured.