Thursday, July 4, 2013

What is the Maximum MTU size for Jumbo Frames??

Recently on Twitter I had this discussion with Michael Webster @vcdxnz001, Patrick Carmichael  @VMCarmichael and Josh Odgers @Josh_odgers  about the Jumbo Frames topic which was just came out of the TCP/UDP joke.

And the answer is Yes, this one is easy "Its 9000".

Most likely people will give this answer when asked the question on Jumbo Frames.

Now  some might go little deeper and keeping in mind the over head and other "surcharge" by VMware vmkernel they may say 8972 to be precise. 

That is also a valid answer but not close to the information received from Intel.

Other vendors might have different opinions so worth to investigate/research with them ;-)

Now read this extract from the same article:

"The maximum MTU setting for jumbo frames is 16110. This value coincides with the maximum Jumbo Frames size of 16128."

Broadcom and other vendors might have different supportability on the MTU size used with Jumbo Frames.

vSphere supports only 9000. People are using mostly 1500 MTU as there are blogs out there which says there is no performance gain in using MTU of 9000 or if there is, its very marginal gain.

So hopefully demystifying the myth (in terms of Eric Sloof @esloof) here about maximum size of MTU available.

Care and share !!


1 comment:

  1. If you're using Super Jumbo Frames they can be upon 64k:

    And it works on IBM's hypervisor for internal vswitch communication in LPAR: