topic Re: Moving network ports from one broadcast domain to other in ONTAP Discussions

Moving network ports from one broadcast domain to other

vims — Wed, 04 Jun 2025 09:59:03 GMT

Hello Gurus,
I have the situation where I need to migrate two ports on each node from one broadcast (Default with 1500 MTU) domain to another ( iscsi with 9000 MTU). I went over a few KBs and have the support ticket opened. How to move a port from one broadcast-domain to another broadcast-domain while LIFs are using the port within ONTAP 9 - NetApp Knowledge Base

However things became complicated lately. What I need to figure is:

- is that possible at all

- is that disruptive

- can it be mitigated in some ways

If anyone done it in the past or have bright idea I would really appreciate it.

Re: Moving network ports from one broadcast domain to other

TMACMD — Wed, 06 Jul 2022 18:06:07 GMT

You can use the broadcast domain merge and split commands. In order to merge the broadcast domains must have the same mtu. So you may need to modify the first broadcast domain first to 9000.

This is slightly disruptive as it communicates with the switch and dues a quick port reset.

Re: Moving network ports from one broadcast domain to other

vims — Wed, 06 Jul 2022 19:06:46 GMT

yes, this is what I thought and kinda prepared all cli commands for that to move forward. Splitting port from Default domain with 1500 MTU to temp domain with 9000 and then merge. This is what KB said.
However answer from NetApp SE totally confused me and I started investigating it deeper.
The whole point of this exercise is to move to the new 10GB SAN switch and get rid of all old 1GB boxes. I was going to simply move cables one by one ( multipath configured) but once I moved we realized there are no 9000 packets going through new switch and figured that issue with domain 😞