[191545] in North American Network Operators' Group
Re: importance of fiber cleaning
daemon@ATHENA.MIT.EDU (Mel Beckman)
Wed Sep 21 05:53:57 2016
X-Original-To: nanog@nanog.org
From: Mel Beckman <mel@beckman.org>
To: Baldur Norddahl <baldur.norddahl@gmail.com>
Date: Wed, 21 Sep 2016 09:53:49 +0000
In-Reply-To: <e95dcd56-c958-68b0-a947-336dd1b0ade2@gmail.com>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
This is a very comprehensive article, and worth handing out to techs. I hav=
e one comment on Balder=92s OTDR suggestion, and one on the article=92s mic=
roscope instructions.
Although it certainly can=92t hurt to run an OTDR test (except for extended=
downtime), I fear hauling out the extra gear will prompt many techs to put=
off fiber cleaning. In my experience, just doing the cleaning solves 99.9%=
of the problem. Anything that an OTDR would pick up would likely severely =
impact performance, while dirty connector will just increase the error rate=
.
Also, the article didn=92t mention eye safety when using a fiber microscope=
. The example showed a USB digital video microscope, but many maintainer ki=
ts in the field have much cheaper direct-view optical microscopes. Viewing =
an energized fiber with a direct-view microscope can cause major eye damage=
. I recommend all fiber kits throw out their optical scopes and substitute =
a USB or WiFI scope (some of these can be used with a cell phone or tablet)=
.=20
-mel
> On Sep 21, 2016, at 1:58 AM, Baldur Norddahl <baldur.norddahl@gmail.com> =
wrote:
>=20
> It is a good article. It is missing a few points:
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> If you are going to do the full efford of cleaning and then microscope ea=
ch connector, you would also want to finish off by doing a OTDR scan of the=
link. This is your documentation for a clean link.
>=20
> Always use optics that can monitor the signal level. The reality is that =
best practice, as described in the article, will not always be followed. In=
most case you will be good anyway as long your optics report back a signal=
strength with a good margin. Have your automated monitoring system watch o=
ver those signal levels.
>=20
> Slightly dirty connectors will often give a sufficient link quality anywa=
y if you have plenty of power budget to spare. We use many 1G single mode B=
IDI optics which cost about 10 USD each for 20 km modules and most of the l=
inks are only 1-5 km. The customer end of those links are probably all half=
dirty, but nobody cares as long we get a strong signal back with power bud=
get to spare.
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> Regards,
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> Baldur
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> On 09/21/2016 07:56 AM, Mikael Abrahamsson wrote:
>>=20
>> https://www.sunet.se/blogg/long-read-cleanliness-is-a-virtue/
>>=20
>> This is an excellent article regarding fiber cleaning and its importance=
. Please do share with other people in our business. I'm sure lack of prope=
r fiber cleaning causes a lot of unneccessary outages and operational probl=
ems worldwide, partly because people aren't aware of its importance.
>>=20
>=20
