topic Re: MTU Administrative in Simulator Discussions

MTU Administrative

kenedem00 — Wed, 04 Jun 2025 20:09:39 GMT

We have port e3a configured with an MTU size of 9000, however when you look at the end of the attached picture, you will see MTU Administrative which is default 1500.

What is MTU Administrative and why is it 1500. Do we have to change it also to 9000.

I am interested to know what it is

Regards

Ken

Re: MTU Administrative

SeanHatfield — Thu, 30 Jun 2016 13:27:27 GMT

Its administratively set to 1500, but it is operating at 9000. What does the rest of the port channel look like? You may need to pull your ports out of the ifgrp, net port mod -mtu-admin <desired value> then add them back to the ifgrp. Then add the ifgrp to a broadcast domain. MTU is managed at the broadcast domain level, and all ports within a broadcast domain must have the same MTU.