Comment 3 for bug 2020410

Did you try adding a router to the provider network (at least as a workaround until this gets figured out)?

Do you have dhcpv6 options?
With this: "In contrast to IPv4, this allows only for reachability of the default GW and not other hosts in the same subnet which reside outside of OVN.", you mean you don't have reachability to IPs on the provider network range, but that are unknown to OpenStack/OVN, right?

I've been on discussions with other folk about a more "BGP/EVPN native" way of implementing both l2 and l3 vnis. I'll ping him for his input here.