What is MTU?
| Maximum Transmission Unit |
|
The largest size of packet that can be sent over a link. This is determined by the underlying network, but must be taken account of at the IP level. IP packets, which can be up to 64K bytes each, must be packaged into lower-level packets of the appropriate size for the underlying network(s) and re-assembled on the other end. When a packet must pass over multiple networks, each with its own MTU, and many of the MTUs are unknown to the sender, this becomes a fairly complex problem. See path MTU discovery for details. Often the MTU is a few hundred bytes on serial links and 1500-odd on Ethernet. There are, however, serial link protocols which use a larger MTU to avoid packet packet fragmentation at the ethernet/serial boundary, and newer (especially gigabit) Ethernet networks sometimes support much larger packets because these are more efficient in some applications. |
Beginner's Help
BUG Club Home
