On Thu, Aug 10, 2017 at 06:53:18PM +0000, Mark Michelson wrote: > On Thu, Aug 10, 2017 at 1:14 PM Ben Pfaff <[email protected]> wrote: > > > On Thu, Aug 10, 2017 at 02:41:30PM +0000, Mark Michelson wrote: > > > I'm curious about the current behavior when ovn-controller originates a > > > packet and transmits it over a link-local IPv6 multicast address. Will > > the > > > packet be delivered only to nodes on the same chassis, or can the packet > > > also reach on-link nodes on other chassis? > > > > When an OVN logical switch receives an Ethernet broadcast or multicast > > packet from a given port, it forwards it to all of its other logical > > switch ports, regardless of chassis. There are special cases for ARP > > and IPv6 ND, to avoid forwarding them across chassis for known IP > > addresses. I don't think that we have any special cases for IPv6 > > link-local multicast. Limiting these within a chassis would probably > > require new mechanisms, because logical flows, by design, do not respect > > physical boundaries. > > > Interesting you mention IPv6 ND here. RAs fall under the umbrella of IPv6 > ND. So depending on how IPv6 ND is detected, it may be that RAs will be > limited from being sent to other chassis. The interesting bit here is the > "for known IP addresses" part. I'll take a closer look at the flows to see > what that means. If the all-nodes link-local multicast address is one of > these known IP addresses, then things might just work without having to do > much extra.
My wording probably made it sound like there's more than there really is. The ND support handles only one special case: when a VM sends a neighbor solicitation for an IPv6 address's Ethernet address, the logical switch responds with a neighbor advertisement that supplies that Ethernet address. The ND support doesn't handle RAs. _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
