[ovs-dev] [PATCH v6] ovn: Connect to remote lports through localnet port.

[Han Zhou]

On Thu, Feb 25, 2016 at 12:43 PM, Russell Bryant <russell at ovn.org> wrote:
>
>
>
> On Thu, Feb 25, 2016 at 1:12 PM, Han Zhou <zhouhan at gmail.com> wrote:
>>
>> Before this patch, inter-chassis communication between VIFs of same
>> lswitch will always go through tunnel, which end up of modeling a
>> single physical network with many lswitches and pairs of lports, and
>> complexity in CMS like OpenStack neutron to manage the lswitches and
>> lports.
>>
>> With this patch, inter-chassis communication can go through physical
>> networks via localnet port with a 1:1 mapping between lswitches and
>> physical networks. The pipeline becomes:
>>
>> Ingress -> Egress (local) -> Ingress (remote) -> Egress
>>
>> The original tunneling mechanism will still be used if there is no
>> localnet port configured on the lswitch.
>>
>> Signed-off-by: Han Zhou <zhouhan at gmail.com>
>> Acked-by: Russell Bryant <russell at ovn.org>
>
>
> I think there may be another problem with this.
>
> We create flows for doing arp replies for all ports on a logical switch.
Once we go to this model, if an entity external to OVN sends an arp request
for an IP address assigned to a VM on a provider network, I believe *every*
hypervisor is going to generate an arp response due to those flows.
>
> One way to resolve this would be to determine whether a logical switch
has a localnet port before creating these logical flows.  If a localnet
port exists, add "inport != <the-localnet-port>" to the match for the arp
reply flows.
>
> --
> Russell Bryant

This is a real problem! I will work on the arp reply flow change and come
with v7.


--
Best regards,
Han