Comment 8 for bug 1618025

I checked on the neutron IRC and MTU cannot be set by API/GUI/CLI. MTU is calculated by neutron as per your config options global_physnet_mtu and such, but it cant be set. There is a separate page in user guide for MTU in newton http://docs.openstack.org/draft/networking-guide/config-mtu.html

Via neutron net-update or REST API its not possible,cause I checked the parameters and it didnt have MTU. Only neutron ipsec-site-connection-update is the cli I could see MTU as a parameter.

A GET can let MTU be returned in network payload, assuming your plugin supports net-mtu API extension. POST(edit) will not work.

It was suggested, we could in theory allow to request MTUs that are lower than plugin calculated, that would be a feature request but only if there is valid usecase around to lower your MTU.

I am cancelling this defect based on this discussion