Range using single-mode SFPs across multi-mode fiber

Chuck Anderson cra at WPI.EDU
Thu Dec 15 03:46:39 UTC 2011

On Wed, Dec 14, 2011 at 10:38:47PM -0500, Keegan Holley wrote:
> 2011/12/14 oliver rothschild <orothschild at 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?

In my case, it was installed for compatibility with FDDI, and used
mostly for 10BASE-FL and 100BASE-FX, which work up to 1 or 2km, until
we started using it for 1000BASE-LX.

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