topic Do Not Fragment bit in Fabric Engine 'Ping' in ExtremeSwitching (VSP/Fabric Engine)

Do Not Fragment bit in Fabric Engine 'Ping'

tcsr121 — Wed, 26 Feb 2025 15:22:21 GMT

Hi
I want to test MTU between two Fabric Extend endpoints both running 9.0.4 that traverse a third party network where the third party does not always set the path MTU to allow FE (it's usually 1900 end to end).
I'm pinging from the tunnel interface on our core switch to a remote logical interface address that I know works as follows:

ping 10.a.b.c datasize 1900 vrf fe-int source 10.x.y.x

This works - but then so does

ping 10.a.b.c datasize 9000 vrf fe-int source 10.x.y.x

as I know the intervening network has a limit of 1900 I'm guessing that packets are being fragmented which makes the test useless. There seems to be no 'do not fragment' option for ping (there is with Cisco). Is there an option I'm missing or a better test on Fabric Engine?? As MTU is limited to 1500 elsewhere I can only check directly between the two Extreme switches.

Re: Do Not Fragment bit in Fabric Engine 'Ping'

Jave — Thu, 27 Feb 2025 13:35:55 GMT

Hi @tcsr121

Already asked for this functionality years ago...with no luck unfortunately.

Regards.

Re: Do Not Fragment bit in Fabric Engine 'Ping'

tcsr121 — Thu, 27 Feb 2025 13:40:53 GMT

yes @Jave I read your post - hopefully more people will ask the same question - odd that the functionality is there in EXOS but not VOSS

Re: Do Not Fragment bit in Fabric Engine 'Ping'

CordScott — Mon, 03 Mar 2025 22:12:17 GMT

This really should be there considering the jumbo frame requirements in Extreme Fabric.

Re: Do Not Fragment bit in Fabric Engine 'Ping'

SamPirok — Thu, 06 Mar 2025 18:06:12 GMT

Hey guys, just wanted to mention that opening a feature request with your local sales engineer would help raise this request to management's attention faster. If you're unsure who your local sales rep is, please let me know generally where you're located and I'll find a sales engineer to assist you.

Re: Do Not Fragment bit in Fabric Engine 'Ping'

Jave — Fri, 07 Mar 2025 13:40:11 GMT

Hy @SamPirok

I've done this several times for over two years now, but it is the same old story.

Regards.

Re: Do Not Fragment bit in Fabric Engine 'Ping'

tcsr121 — Tue, 11 Mar 2025 11:34:33 GMT

Thanks I've raised it with our Premier Support Delivery Manager
I have to say that "Accepted Solution" is stretching things a bit - currently there is no solution.