See Packet Flow in an MPLS VPN Environment for more information. Over Ethernet Label stack entries precede the network layer header and follow the data link layer headers. Label fields add a total of 4 bytes to every frame. Additional tags may be present due to the utilization of the 802.1Q protocol. For example, if a standard 802.3 frame carries a payload of 1500 bytes and has a total size of 1518 bytes, adding a label field would cause the total size to be 1522 bytes.
Most hardware supports a maximum size larger than the conventional payload size.
Due to the user's determination. Hardware Switches Switches only perform Level 2 switching. After examining the addresses, they forward the packets to the base. They are not considered LSRs. Jumbo frame support is available only on Gigabit Ethernet interfaces.