.. acc1552590687558 .. _the-ethernet-mtu: ============ Ethernet MTU ============ The |MTU| of an Ethernet frame is a configurable attribute in |prod|. Changing its default size must be done in coordination with other network elements on the Ethernet link. In the context of |prod|, the |MTU| refers to the largest possible payload on the Ethernet frame on a particular network link. The payload is enclosed by the Ethernet header (14 bytes) and the CRC (4 bytes), resulting in an Ethernet frame that is 18 bytes longer than the |MTU| size. The original IEEE 802.3 specification defines a valid standard Ethernet frame size to be from 64 to 1518 bytes, accommodating payloads ranging in size from 46 to 1500 bytes. Ethernet frames with a payload larger than 1500 bytes are considered to be jumbo frames. For a |VLAN| network, the frame also includes a 4-byte |VLAN| ID header, resulting in a frame size 22 bytes longer than the |MTU| size. In |prod|, you can configure the |MTU| size for the following interfaces and networks: .. _the-ethernet-mtu-ul-qmn-yvn-m4: - The management, cluster host and |OAM| network interfaces on the controller. The |MTU| size for these interfaces is set during initial installation. .. xbooklink For more information, see the `StarlingX Installation and Deployment Guide `__. To make changes after installation, see |sysconf-doc|: :ref:`Change the MTU of an OAM Interface Using Horizon `. - Additional interfaces configured for container workload connectivity to external networks, In all cases, the default |MTU| size is 1500. The minimum value is 576, and the maximum is 9216.