[neutron][ovn] ipv6 in virtual networks

Piotr Misiak piotrmisiak1984 at gmail.com
Thu Feb 11 11:20:00 UTC 2021

On 10.02.2021 21:08, Brian Haley wrote:

> On 2/10/21 1:11 PM, Piotr Misiak wrote:
>>   - Routing is not working at all
>> Besides those, I can't imagine how upstream router will know how to
>> reach a particular private network with GUA IPv6 addresses (to which
>> virtual router send packets to reach a particular private network?). I
>> have a standard external network with IPv6 GUA /64 subnet and virtual
>> routers which connects private networks with IPv6 GUA /64 subnets with
>> external network. I thought that OVN virtual router will send ICMPv6 RA
>> packets on external network with reachable prefixes and upstream router
>> will learn routing info from those but I don't see any RA packets sent
>> by OVN on external network, I see only RA packets from an upstream
>> router. How this should work and be configured? How to configure GUA
>> IPv6 addresses on virtual private networks? Is it supported by
>> Neutron/OVN?
> IPv6 prefix delegation is what you want, it's one of the 'gaps' with
> ML2/OVS, https://bugs.launchpad.net/neutron/+bug/1895972
> There is a list of known items at
> https://docs.openstack.org/neutron/latest/ovn/gaps.html
> So in order to use a globally-reachable IPv6 address you should use a
> port from a provider network in the instance.
Thanks Brian for the prompt response.

Does this mean that the only functional IPv6 scenario in Neutron/OVN is
where VMs are directly connected to an IPv6 GUA provider network?

BGP peering is not supported in Neutron/OVN, so virtual routers cannot
advertise their prefixes (use case where private network prefix is
manually specified by the user or it is automatically assigned from a
default IPv6 subnet-pool defined in Neutron)

IPv6 PD is not supported in Neutron/OVN, so virtual routers cannot
request an IPv6 prefix from an upstream router


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