>
>
> Not quite. What I'm referring to is when you have an overlay that spans
> multiple compute nodes. When a broadcast packet needs to be sent to all VMs
> in a network, it needs to be duplicated by the sending hypervisor onto a
> tunnel to every other compute node with a VM in the network.
>

I see what you mean. You are right.


>
> On Wed, Jan 13, 2016 at 1:11 PM, Guru Shetty <[email protected]> wrote:
>
>>
>>
>> On 13 January 2016 at 11:06, Kevin Benton <[email protected]> wrote:
>>
>>> Hi,
>>>
>>> I looked through the list and see that someone already asked about
>>> multicast addresses as a target for VXLAN tunnels[1]. Since it's not
>>> supported, what is the suggestion to prevent broadcast/multicast traffic in
>>> a tenant's network from wiping out the network due to the duplication cost?
>>>
>>> This is something the current OVS plugin for Neutron in OpenStack
>>> suffers from and it seems OVN will have the same issue as far as I can tell.
>>>
>>
>> Assuming I understood your statement correctly, with OVN, only one
>> broadcast packet goes in the tunnel and then it gets replicated in the
>> hypervisor. So the load is on the CPU instead of the network.
>>
>>
>>>
>>> For example, without severely rate-limiting or completely blocking
>>> broadcast/multicast, a tenant network with 100 VMs on it can max out a 10
>>> Gbps interface adapter with a 100 mbps broadcast/multicast stream.
>>>
>>> 1. http://openvswitch.org/pipermail/discuss/2015-December/019632.html
>>>
>>> Cheers
>>> --
>>> Kevin Benton
>>>
>>> _______________________________________________
>>> discuss mailing list
>>> [email protected]
>>> http://openvswitch.org/mailman/listinfo/discuss
>>>
>>>
>>
>
>
> --
> Kevin Benton
>
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