Neutron/OVN + IPv6

Tiago Pires tiagohp at
Tue Jun 21 20:44:23 UTC 2022

Hi Tim,

>From the border routers to the Internet, it is not a problem to summarize
the /64 in /48 for example.
My point is how to know the next-hop neutron router's IP that has a subnet
/64 behind it? When you have many routers, we need a dynamic mechanism for
I think the neutron ML2/OVN gap is to not support IPv6 Prefix delegation
that would be the better solution for it.
And Neutron BGP dynamic with OVN is not supported as I could check in the
So, I don't know if there is another way to use IPv6 using the integration
with Neutron and OVN.


Tiago Pires

Em ter., 21 de jun. de 2022 às 15:35, < at>

> I think that you’d normally advertise much larger subnets than /64 and
> then subnet those for different domains. Routing in ipv6 should be much
> more straightforward as there should be no NAT, which ought to make it much
> easier to work out what’s talking to what.
> On 21 Jun 2022, at 18:21, Tiago Pires <tiagohp at> wrote:
> Hi all,
> I am trying to figure out how to enable workloads on overlay to use IPv6
> addresses and communicate with external networks.
> I have to use Neutron ML2/OVN in my scenario and I have doubts regarding
> how the external networks(Internet) can know how to reach the VMs using
> IPv6 address behind a regular neutron router.
> I was checking this link
> that uses the BGP speaker on neutron in order to advertise the /64 subnets
> to a border router, that option should work fine but Neutron/BGP Speaker is
> not supported with OVN as I could check on the documentation.
> How are you using IPv6 integration (Neutron/OVN) to advertise the /64
> subnets?
> Tiago Pires
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