Apple 10GbE module Jumbo Frame limit

[hajime]

Hi, when I had a M2 and M2 Pro Mini, I could enable Jumbo Frame but the systems defaulted to 9000. Is this a limitation of Apple 10GbE module, the chipset, Silicon Mac or MacOS? Can we go higher without affecting stability?

 

[chown33]

The limit of 9000 appears to be widely used.

Jumbo frame - Wikipedia

en.wikipedia.org

The use of 9000 bytes as preferred payload size for jumbo frames arose from discussions within the Joint Engineering Team of Internet2 and the U.S. federal government networks.[7] Their recommendation has been adopted by all other national research and education networks.[citation needed] Manufacturers have in turn adopted 9000 bytes as the conventional MTU size, with a total jumbo frame size of between 9014 and 9022 bytes with ethernet headers included.[8] Most Ethernet equipment can support jumbo frames up to 9216 bytes.[9]

As to exactly where the restriction lies, what difference would it make? If it's the OS or the ethernet chip, you're still constrained by whichever limit is smaller. You could try finding a chip that you know supports larger frames, but you'd need to dig into chip datasheets. If you then find the OS imposes a limit, you haven't gained anything.

Please describe what you're trying to accomplish by using larger frames.

 

[hajime]

The limit of 9000 appears to be widely used.

Jumbo frame - Wikipedia

en.wikipedia.org

As to exactly where the restriction lies, what difference would it make? If it's the OS or the ethernet chip, you're still constrained by whichever limit is smaller. You could try finding a chip that you know supports larger frames, but you'd need to dig into chip datasheets. If you then find the OS imposes a limit, you haven't gained anything.

Please describe what you're trying to accomplish by using larger frames.

Faster reliable data communication.

 

[chown33]

Faster reliable data communication.

How fast would be fast enough?

I ask because there are inescapable limits on what could be achieved even with a maximally jumbo-sized frame.

Larger frames have more potential for errors. Larger frames take longer to send. So if a jumbo frame has an error detected by the recipient, it has to be resent, and the cost can be higher than if frames were smaller. Overall efficiency depends on things like error rate, signal quality, and other factors not directly related to frame size.

There are also factors like latency of the computers involved.

There are also hard limits, like packet size, that are dictated by the protocol. Example: the 16-bit length field in IPv4 means no packet can possibly exceed 64KiB.