[147576] in North American Network Operators' Group
Re: Range using single-mode SFPs across multi-mode fiber
daemon@ATHENA.MIT.EDU (Mark Foster)
Wed Dec 14 22:47:25 2011
Date: Thu, 15 Dec 2011 16:46:13 +1300
From: Mark Foster <blakjak@blakjak.net>
To: Keegan Holley <keegan.holley@sungard.com>, nanog@nanog.org
In-Reply-To: <CABO8Q6T0YKxipW8R1vSDHh-pL8fmG3pXjPavybQiN3=6mdeVsg@mail.gmail.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On 15/12/11 16:38, Keegan Holley wrote:
> 2011/12/14 oliver rothschild <orothschild@gmail.com>
>
>> Thanks to all who responded to my clumsy first question (both on
>> matters of etiquette and technology). The group I work with (we are a
>> small project acting as a last mile provider) was in the midst of
>> deploying this solution when I posed the question. We put the single
>> mode Juniper SFPs (LX) on to a run of approximately 1670 meters.
>>
> How did you end up with a MM run this long? SX optics are only rated at
> 500 meters at best. Even with mode conditioning jumpers more the 1km is a
> risk. I'm glad it held up during testing though. Just out of curiosity
> did you purchase dark from a provider? Is it inside of a building?
Um.. check that.
https://en.wikipedia.org/wiki/Multi-mode_optical_fiber
"Typical transmission speed and distance limits are 100 Mbit/s for
distances up to 2 km (100BASE-FX
<https://en.wikipedia.org/wiki/100BASE-FX>), 1 Gbit/s to 220--550 m
(1000BASE-SX <https://en.wikipedia.org/wiki/1000BASE-SX>), and 10 Gbit/s
to 300 m (10GBASE-SR
<https://en.wikipedia.org/wiki/10_Gigabit_Ethernet#10GBASE-SR>)."
The old OM1 installations I used to work on started out as 10Mbit hubbed
ethernet links and on the odd occasion would run out to close to 2km
within a campus. They were progressively upgraded with the flow of:
10FX on 3Com Linkbuilder Kit
100FX on 3Com Corebuilder Kit and Allied Telesyn 100FX Media converters
1000SX on a variety of 3Com, Nortel and Cisco kit out to ~220m
1000LX via Mode-Conditioning out to ~900-1000m.
The OM1 only got retired when the distance was >900m or there was budget
to put new fibre on the run, in which case we ran SMF and rigged LX drivers.
Mark.
