Maximal Transfer Unit
From MTU LUG wiki
Maximal Transfer Unit is the largest possibl layer 2 frame size on a network.
Ethernet uses a 1500-byte in the 10Mbps and 100Mbps forms, and commonly uses 9000-byte MTUs in 1000Mbit (Gigabit) ethernet. Ethernet MTus can be as high as 16384 bytes.
PPPoE connections and other tunnels will often use a MTU of 1492, to accout for the tunnel overhead.
Other (less common) MTU sizes:
- 16 Mbps Token Ring: 17914
- 4 Mbps Token Ring: 4464
- SONET: 4460
- FDDI: 4352
- X.25: 576
ATM uses a cell size of 53 bytes, but the LANE layer on top of it emulates a larger MTU.