[ovs-discuss] VXLAN using OVS

[Jesse Gross]

On Tue, Oct 22, 2013 at 9:52 AM, Kyle Mestery (kmestery)
<kmestery at cisco.com> wrote:
> On Oct 22, 2013, at 2:15 AM, Romil Gupta <romilgupta19 at gmail.com> wrote:
>>
>> Hi All,
>>
>> We are using OVS as neutron plugin to use VLAN/ VXLAN. We found that OVS does multiple unicast to send the ARP request instead of sending via Multicast address. But by default Linux bridge supports Multicast.
>>
>> Is there any reason behind why OVS doesn't support Multicast?
>>
>> Thanks in Advance :)
>
>
> Hi Romil:
>
> I'm copying and pasting the answer I gave to you when you asked this question on the openstack mailing list as well:
>
> The only reason is that support for a multicast control plane never made it upstream into OVS. However, there is effort upstream in OVS to synchronize the data plane portions of VXLAN, and when that happens, OVS VXLAN will acquire multicast support.

To clarify this a little bit, the OVS VXLAN dataplane has already been
merged with the upstream Linux kernel. However, VXLAN multicast
learning is really a control plane feature so it would require a
separate implementation in OVS userspace if/when somebody was inclined
to do that.