[j-nsp] 40G QSFP problems on QFX5100 after 16.1R6

[Sebastian Wiesinger]

* Jason Healy <jhealy at logn.net> [2018-08-22 12:22]:
> On Aug 22, 2018, at 4:52 AM, Sebastian Wiesinger <sebastian at karotte.org> wrote:
> > 
> > apparently there is now a PR for this: PR1309613
> 
> I realize you may not have the answers, but if you do...
> 
> 1) Does this affect platforms other than the QFX?

I'm not aware of other platforms affected. We only saw this on QFX.

> 2) Were you seeing the CRC count increase in all cases of traffic loss?

Yes.

> 3) Was there any pattern to the traffic loss (e.g., every X seconds,
> certain types of traffic, certain percentage of all traffic)?

No, there was no apparent pattern. Sometimes we could make the problem
go away OR reoccur by flapping interfaces.

> I ask because we have a setup right now with a EX4600 VC going to a
> QFX5100 via 40Gb DWDM fiber.  Client devices are seeing "pauses" in
> traffic with ICMP loss or severe delay.
>
> However, there are no CRC errors reported on either switch as
> mentioned in the PR.  Also, we've only observed serious loss over
> WiFi clients so there are still plenty of possible culprits.
>
> This is our only EX4600 stack, and our first 40Gb optics, so we
> don't have a similar working setup elsewhere that's known to be
> good.

I really can't say. If you open a case perhaps let the TAC engineer
crosscheck with this PR?

Regards

Sebastian

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