I have setup an openstack cloud according to the guid I found https://github.com/mseknibilel/OpenStack-Grizzly-Install-Guide/blob/OVS_MultiNode (here) and it works as expected with quantum networking and gre tunnels. I then tried to add another compute node; again following the instructions in the compute node section of the guide (of course changing ip addresses according to new computer) this new node mostly works... The vm's on the new compute node can ping vm's on the other compute node using their internal ip as expected, but I cannot ping any vm's on the new compute node via their assigned floating ip. I have double checked the configuration files, now I am puzzled on how to continue debugging this issue.