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JSI Tip 4734. What are the default MTU sizes for different network topologies?

The MTU (Maximum Transfer Unit) specifies the maximum transmission unit size of an interface, and is usually determined by negotiation at the link layer of the driver.

The upper level protocols normally optimize pack size for each medium.

If a network adapter driver uses LAN emulation mode, it may report a higher MTU than expected, which Windows will use.

Windows XP      |   Windows NT / Windows 2000
Network MTU (bytes)   |   MTU (bytes)
16 Mbps Token Ring 17914   |   17914
4 Mbits/Sec Token Ring 4464   |   4464
FDDI 4352   |   4352
Ethernet 1500   |   1500
IEEE 802.3/802.2 1492   |   1492
X.25 576   |   576
PPPoE (WAN Miniport) 1480   |   N/A

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