What is the nominal MTU for LAN communications?

A. 1,500 bytes
B. 1,500 bits
C. 9,000 bytes
D. 9,000 bits

A. The nominal MTU size is 1,500 bytes of data. It may also be advertised as 1,518 bytes, which is calculated from 1,500-bytes (payload) + 6 bytes (source MAC address) + 6 bytes (destination MAC address) + 2 bytes (type field) + 4 bytes (FCS) = 1,518 bytes. If 802.1Q VLAN tagging is being used, it can be advertised as 1,522 bytes to allow for 4 bytes for tagging. If ISL VLAN tagging is being used, ISL requires 30 bytes + 1,518 bytes = 1,548 bytes.