[c-nsp] 10gig Link Bouncing Consistently

Justin Krejci JKrejci at usinternet.com
Wed Apr 3 19:03:19 EDT 2013

Unfortunately SR/MMF transceivers have no DOM support.

We'll definitely get some fiber power meter tests ran during "the problem" time @ 850nm

Physical inspection has been completed already as well. No obvious places where there would be any sort of environmental impact and no current signs of distress/damage to the fibers.

Fiber ends have been cleaned thoroughly.

From: cisco-nsp-bounces at puck.nether.net [cisco-nsp-bounces at puck.nether.net] on behalf of Michele Bergonzoni [bergonz at labs.it]
Sent: Wednesday, April 03, 2013 2:29 AM
To: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] 10gig Link Bouncing Consistently

> Beginning several days ago both links began flapping every 5 and a half
> hours, both links have this happen within a couple of minutes of each
> other.
> They will flap for several minutes and then return to normal operation
> requiring no user action and the ports never enter err-disable or show
> any other symptoms.

Your story popped me up a distant memory of a heating system that
happened to leak steam on a fiber cable. That cable contained all the 4
fibers of a presumed redundant connection.

I would not let the next predicted flapping time pass without:

* "show interface transc det" when everything works, and when things go bad
* technicians at both ends ready to disconnect one line and test the
loss on the fibers with appropriate instruments, in the first window
(~850 nm)
* physical inspection of the fiber run, if feasible

If the fibers turn out to be OK, when you have a Cisco 6509 on one end
and a Netgear on the other, and you need to try to replace one of them,
we all know where to start.


Ing. Michele Bergonzoni - Laboratori Guglielmo Marconi S.p.a.
Phone:+39-051-6781926 e-mail: bergonz at labs.it
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