# Revision history [back]

I think with Havana and OVS (ML2 or OVS plugin), VXLAN works the same way as GRE. VXLAN is just being used as a different framing protocol - IP/UDP vs IP/GRE.

It can't be anything todo with MTU as DHCP packets are very small. Also OVS 1.10.0+ is now doing IP fragmentation, and that problem was only for some Internet sites that ignored the ICMP errors.

I guess it's something todo with the flows on controller's br-tun. Can you append the output of sudo ovs-ofctl dump-flows br-tun to the question:

Also try running that command, get the instance to do more DHCP requests (from VNC console), re-run the command and compare the statistics to see which flows are being hit.

Also can you include sudo ovs-vsctl show from the controller.

I think with Havana and OVS (ML2 or OVS plugin), VXLAN works the same way as GRE. VXLAN is just being used as a different framing protocol - IP/UDP vs IP/GRE.

It can't be anything todo with MTU as DHCP packets are very small. Also OVS 1.10.0+ is now doing IP fragmentation, and that problem was only for some Internet sites that ignored the ICMP errors.

I guess it's something todo with the flows on controller's br-tun. Can you append the output of sudo ovs-ofctl dump-flows br-tun to the question:

Also try running that command, get the instance to do more DHCP requests (from VNC console), re-run the command and compare the statistics to see which flows are being hit.

Also can you include sudo ovs-vsctl show from the controller.

Update: The second flow in table 0 (matches port 2, the vxlan port) is not being hit. Linux does not seem to be sending the incoming VxLAN packets to it. VxLAN uses UDP port 4789 by default, so this should give something: netstat -an | grep 4789

Ubuntu 13.10 is very new and maybe has not been used much during development. What kernel is it? You might try some different kernel versions.

I think with Havana and OVS (ML2 or OVS plugin), VXLAN works the same way as GRE. VXLAN is just being used as a different framing protocol - IP/UDP vs IP/GRE.

It can't be anything todo with MTU as DHCP packets are very small. Also OVS 1.10.0+ is now doing IP fragmentation, and that problem was only for some Internet sites that ignored the ICMP errors.

I guess it's something todo with the flows on controller's br-tun. Can you append the output of sudo ovs-ofctl dump-flows br-tun to the question:

Also try running that command, get the instance to do more DHCP requests (from VNC console), re-run the command and compare the statistics to see which flows are being hit.

Also can you include sudo ovs-vsctl show from the controller.

Update: The second flow in table 0 (matches port 2, the vxlan port) is not being hit. Linux does not seem to be sending the incoming VxLAN packets to it. VxLAN uses UDP port 4789 by default, so this should give something: netstat -an | grep 4789

Ubuntu 13.10 is very new and maybe has was probably not been used much by Neutron developers during development. the Havana cycle. What kernel is it? You might try some different kernel versions.

versions or upgrade OVS. I think 13.10 uses the 3.11 kernel, and the OVS FAQ says its requires OVS 2.1.x