(1) (Maximum Transmission Unit, Maximum Transfer Unit) The largest frame size that can be transmitted over the network. For example, an Ethernet MTU is 1,500 bytes. Messages longer than the MTU must be divided into smaller frames. The layer 3 network protocol, typically IP, extracts the MTU from the layer 2 data link protocol such as Ethernet, and fragments the messages into that frame size so that they can travel over the lower layer. See path MTU.|
(2) (Multi-Tenant Unit) A building with multiple offices or apartments. MTUs are more economical to target for installing DSL and other broadband links than single-occupancy offices or houses. See MDU and BLEC.