[120754] in North American Network Operators' Group
Re: dark fiber and sfp distance limitations
daemon@ATHENA.MIT.EDU (Michael K. Smith)
Sat Jan 2 12:08:50 2010
Date: Sat, 02 Jan 2010 09:07:52 -0800
From: "Michael K. Smith" <mksmith@adhost.com>
To: Mike <mike-nanog@tiedyenetworks.com>
In-Reply-To: <alpine.DEB.1.10.1001021156290.15329@uplift.swm.pp.se>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On 1/2/10 2:58 AM, "Mikael Abrahamsson" <swmike@swm.pp.se> wrote:
> On Fri, 1 Jan 2010, Justin M. Streiner wrote:
>
>> The first thing you need to do is test the fiber with an OTDR. If you
>> don't have one, you can probably contract a local cabling company to
>> test it for you.
>
> Why would you want an OTDR report on the fiber, when an attenuation report
> is probably more accurate? OTDR is good for locating WHERE a problem is,
> but if you're seeing .2 dB/km attenuation end-to-end, there is little
> reason to break out the OTDR.
If I was of the opinion that the telco in the original message would act
upon output data to clean up fibers/jumpers/splices, then the OTDR is the
way to go because you can show them exactly where the issues are in the
entire length of fiber.
If the telco isn't going to make any modifications then an optical power
meter would probably be sufficient. Either you can hit the distance in your
loss budget or not.
Mike
