I can set the ethernet port MTU to a maximum 9000 however

I can set the wireless radio MTU to a maximum 1630 only and the largest pace size to pass across the radio will be 1602.

Is there any MTU limitation for radio?

1 Answer 1


Ethernet (IEEE 802.3) and Wi-Fi (IEEE 802.11) are two completely separate layer-1/2 protocols. Don't make the mistake of confusing them.

There is no real defined standard for ethernet jumbo frames, they are sort of a kludge and may not work from vendor to vendor.

Wi-Fi has specific, strict, interoperability testing by the Wi-Fi Alliance. There are no jumbo frames for Wi-Fi, although Wi-Fi frame payloads (2312 octets) can be larger than standard ethernet frame payloads (1500 octets). Wi-Fi is also required to regularly yield the airwaves because it is a shared medium. Wi-Fi must even yield to completely different Wi-Fi, or other, networks on the same frequency. Having jumbo frames would disrupt the timing of this but requiring a use of the frequency longer than should be allowed.

One problem you can run into with Wi-Fi is frame payloads can be larger than the standard ethernet payload. Most traffic originating on Wi-Fi will need to get to ethernet at some point. WAPs are translating bridges, whereas ethernet switches are transparent switches. WAPs need to translate Wi-Fi frames into ethernet frames for those frames destined for a wired network. Any frames with payloads larger than what the ethernet side of the WAP can handle must be dropped.

  • 3
    Great description, I'd only add that, in fact, the 1500 octet limit on Ethernet was originally there for a similar reason. The first Ethernets (per DIX spec) were a shared cable and so the frame size had to be limited to free up the shared channel. Jumbo frames (pretty much) only work because all new Ethernet installations use only UTP in full-duplex, so the only shared resource is the forwarding queue in the switch interface.
    – MAP
    Aug 5, 2016 at 6:50

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