topic Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down in ExtremeSwitching (VSP/Fabric Engine)

Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

dabbler — Wed, 26 Jun 2024 08:47:03 GMT

I have 2 VSPs, VSP1 and VSP2 that have SMLT fibre connections to EXOS switch stacks that use sharing.

I built a new EXOS switch stack to replace an existing one, created a new SMLT and all that worked fine. I then disconnected both fibres from the existing EXOS stack and connected both fibres from the new EXOS stack as I need to use the existing VSP SMLT ports.

The fibre on VSP2 works and provides connectivity but the fibre port on VSP1 is now down. Changing fibre cables, SFPs, rebooting the EXOS and VSP did not help.

Anyone know why moving both fibres on an SMLT connection to a new switch stack would cause this?

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

RobertD1 — Wed, 26 Jun 2024 12:56:18 GMT

Type show int gig state command and check reason for port down state. If you have SLPP configured and that detected a loop during the move then this could be a reason. SLPP will disable the port and needs to be re-enabled to make it work again. If you saved the VSP config and rebooted it would keep the port in an admin down state.

On EXOS use the show sharing command to check the sharing status. Make sure the fibre ports used belong to the LAG.

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

XTRMUser — Wed, 26 Jun 2024 13:44:02 GMT

You mentioned fiber with SFP's. In my experience, you disconnect the fiber and then pull out the SFP. I wonder if you got some dirt, and need to clean the SFP and fiber ends. I don't know if you use EDM, but if you do, check for errors on the SFP ports (EXOS and VSP ends). I don't know the CLI commands for checking that.

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

dabbler — Fri, 28 Jun 2024 09:27:20 GMT

I pulled out the fibers and SFPs and I also swapped the SFPs with spares and changed the fibres cables to ones that I knew worked OK, but nothing helped. I then swapped the 2 fibres back to the original switch stack and the same thing happened... one port on VSP1 shutdown so I thought it may be related to SMLT. Does in need a 'reset' ?

I also checked for errors using "show int gig error" but there are 0 errors on the SMLT ports.

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

dabbler — Fri, 28 Jun 2024 09:25:46 GMT

Here is the output of the command, unfortunately no reason given on ports 1/3 (the new switch stack that the fibres were moved to) and 1/13 (the original stack I tried moving the fibres back to)

I checked the EXOS sharing too and the ports are correct. I used the exact same config on the new stack as the original stack.

Should I maybe have shut the SMLT ports down before moving the fibres?

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

RobertD1 — Fri, 28 Jun 2024 14:50:32 GMT

Sounds like a physical L1 problem if you are unable to go back to the original port. Don't see a reason for the port being down and is still admin enabled. Sometimes good to disable one side especially when changing stacking but you are not doing this here.. Check show pluggable basic to see transceiver recognised and show pluggable detail to see info on status of tx and rx signals (should be normal with no warnings for both). Did you get the tx and rx wrong way around when you moved the fibre cable maybe? Is your VIST up?

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

dabbler — Mon, 01 Jul 2024 07:32:22 GMT

VIST is UP ok.
I ran a show pluggable details and the port on VSP1 is showing

RxPower(dBm) -20.0 -19.0 -40.0 0.0 1.0 Low Alarm

I assume the -40 is because the VSP port is down and not transmitting anything

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

RobertD1 — Mon, 01 Jul 2024 08:10:36 GMT

If you compare with a working port the low alarm should be 'normal' and a stronger signal, -40 is not normal. You could check with your phone to see if the fibre is receiving light? Make sure tx and rx cores are inserted correctly / right way around (sometimes have to swap them if using new fibre path).

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

dabbler — Mon, 01 Jul 2024 13:24:06 GMT

I checked and there is no light being transmitted by the VSP port on either fibre core, I'm thinking because the port is down. I tried a shut/no shut, rebooted the EXOS switch stack, the VSP, replaced the SFPs and fibre but nothing made any difference.

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

RobertD1 — Mon, 01 Jul 2024 17:19:02 GMT

Are you seeing light from the fibre?

Are you using new fibre for the new EXOS stack?

Have you tried splitting the LC connector and changing the tx and rx around at one end?

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

dabbler — Tue, 02 Jul 2024 13:21:13 GMT

There is no light at all being transmitted from the VSP port on either core, so swapping the tx/rx round won't be of help at this point. I tried swapping the fibres round on the 2 ports on the EXOS switch stack but the fault stayed with the port, indicating the fibre cables are ok.

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

RobertD1 — Tue, 02 Jul 2024 14:32:27 GMT

If you disable the working leg does it start to work then? Have seen this when same port goes to wrong stack. Otherwise, I suggest you raise a case.

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

dabbler — Wed, 03 Jul 2024 12:59:16 GMT

I tried pulling the working fibre, but no difference.

However, running "show pluggable detail" on the VSPs and looking at the SFP type showed "10GbSR". The EXOS stack command "show port transceiver information detail" showed a "SF+LRM". It turned out that whoever built the original EXOS stack did not use our standard short-haul SFPs, they used 1 short haul and one long haul at each end.
I swapped the long haul SFPs out for the standard short hauls and the fibres burst into life.
I should have seen that when checking the rx/tx power earlier.

Thanks a lot for all your help Robert, I appreciate it very much.

Re: Swapping fibres in VSP SMLT to EXOS LAG = SMLT port down

RobertD1 — Wed, 03 Jul 2024 13:57:17 GMT

Glad you got it sorted in the end.