You can now set a default MTU for Tenant networks in the network environment file prior to Overcloud deployment. To use this feature, set NeutronTenantMtu to a value other than 1400 (the default) in the "parameter_defaults:" section of the network environment file. Using jumbo frames (MTU larger than 1500) requires enabling a larger MTU on the Ethernet switches, and can increase the network performance for VMs. The performance increase is greatest with VXLAN, and can result in 3-5x throughput performance. Setting the default Neutron tenant MTU at deployment time saves having to make manual changes to the Neutron and Nova configuration files. If using VXLAN or GRE, the NeutronTenantMtu should be at least 50 bytes smaller than the MTU on the physical network. Now when NeutronTenantMtu is set, then Neutron will use this value to set the MTU on virtual network interfaces for instances.