[ovs-discuss] Residual IP/ARP entry after a VM is powered off -> OVS passing unwanted pkts

Ben Pfaff blp at nicira.com
Wed Sep 1 17:59:27 UTC 2010

I only read your original message quickly, but if I understand it
properly, it sounds to me like OVS is behaving in more or less the same
way as a Ethernet switch would ordinarily behave.  If I understand your
setup, initially you have a VM with a particular MAC address on some
host.  Then you shut down that VM, so there is now nothing on the
network with the MAC address in question.  OVS quickly sees that it
hasn't had any packets from that MAC address on any port, so it starts
flooding packets that are directed to that MAC to all ports.  It will
continue to do that until the VM reappears.  (But eventually the hosts
or VMs sending packets to that MAC will realize that they haven't had
any responses in a while, time out that MAC, and fall back to ARPing for
it, which effectively rate-limits the traffic.)

Does that sound reasonable?

More information about the discuss mailing list