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Why some switches show an MTU of 1522 and some like Cisco show 1500

Kerry Cordero
Routing & Switching
1 min read

There’s no issue here. Cisco is just showing Ethernet MTU, which is 1500. There are 18 header bytes and 4 dotq bytes (18+4=22 bytes). So, Cisco is allowing 1500+18 (1522) to pass through.

1500 bytes = Ethernet MTU
18 bytes = header bytes
4 bytes = dotq bytes
————————————
1522 bytes

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Cisco
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