OVN vlan networks use geneve tunneling for SNAT traffic

[venkata anil]

In OVN driver, traffic from vlan (or any other) tenant network to external network uses a geneve tunnel between the compute node and the gateway node. So MTU for the VLAN networks needs to account for geneve tunnel overhead.

This doc [1] explains about OVN vlan networks and current issue and future enhancements.
There is ovs-discuss mailing list thread [2] discussing the surprising geneve tunnel usage.

[1] https://docs.google.com/document/d/1JecGIXPH0RAqfGvD0nmtBdEU1zflHACp8WSRnKCFSgg/edit#heading=h.st3xgs77kfx4
[2] https://mail.openvswitch.org/pipermail/ovs-discuss/2018-April/046543.html

[YAMAMOTO Takashi (yamamoto)]

why this bug is filed for neutron, rather than networking-ovn?

[Numan Siddique (numansiddique)]

I think its merged in core OVN. And I also think its been addressed in networking-ovn by setting - reside-on-redirect-chassis option to the logical router ports.