[166370] in North American Network Operators' Group
Re: Pad 1310nm cross-connects?
daemon@ATHENA.MIT.EDU (=?utf-8?B?TcOlbnM=?= Nilsson)
Sun Oct 20 01:21:54 2013
Date: Sun, 20 Oct 2013 07:21:42 +0200
From: =?utf-8?B?TcOlbnM=?= Nilsson <mansaxel@besserwisser.org>
To: Chris Costa <ccosta92630@gmail.com>
In-Reply-To: <CAN8DL0XVDUV20-Wk6LYuuuufq22VnNznOVRvwL=_aYt90bagkg@mail.gmail.com>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
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Subject: Pad 1310nm cross-connects? Date: Sat, Oct 19, 2013 at 07:33:19PM -=
0700 Quoting Chris Costa (ccosta92630@gmail.com):
> What are the opinions/views on attenuating short, 1310nm LR cross-connect=
s.
> Assume < 20m cable length and utilizing the same vendor optics on each
> side of the link. Considering the LR transmit spec doesn't exceed the
> receiver's high threshold value do you pad the receiver closer to the
> median RX range to avoid potential receiver burnout over time, or just
> leave it un-padded?
LR usually needs padding in that scenario, IMHO. This also=20
applies to MMR interconnects or other "premises" / "campus" situations. 5
or 10dB depending on patching quality -- sometimes up to 15. The value
is best determined by measuring the signal. Then compare the measurement
with the line card / SFP datasheet and determine the amount of padding
necessary. As you write, the damage from overload is gradual, so simply=20
trusting "it works" is quite bad for longevity reasons.=20
Not all line cards and / or optical modules report the input signal=20
level, so a good meter sometimes is necessary.
Get a good level meter, and a reasonably good light source for=20
testing and calibration purposes. I'm happy with our purchase of
SMLP4-4[0] from AFL Noyes.
--=20
M=C3=A5ns Nilsson primary/secondary/besserwisser/machina
MN-1334-RIPE +46 705 989668
Pardon me, but do you know what it means to be TRULY ONE with your BOOTH!
[0] http://www.aflglobal.com/Products/Test-and-Inspection/Loss-Test-sets/SM=
LP4-4_Single-mode_Multimode_Loss_Test_Kits.aspx
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