[147574] in North American Network Operators' Group
Re: Range using single-mode SFPs across multi-mode fiber
daemon@ATHENA.MIT.EDU (Chuck Anderson)
Wed Dec 14 22:34:04 2011
Date: Wed, 14 Dec 2011 22:33:01 -0500
From: Chuck Anderson <cra@WPI.EDU>
To: nanog@nanog.org
Mail-Followup-To: nanog@nanog.org
In-Reply-To: <CAED=9Er2TjB5Bkac74CcB6gOpEyjC3j2hWDHPdG5TNu2mzZ_Wg@mail.gmail.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Wed, Dec 14, 2011 at 10:02:58PM -0500, oliver rothschild wrote:
> 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. We
> successfully established a 1G ethernet connection. Testing to date has
> been meager, but shows that the link is viable. Under significant load
> there is some minor packet loss. Since the link far exceeds the amount
> of data it required, we have decided to continue using it.
> Interestingly neither interface showed any physical errors.
Technically you should be using offset-launch "mode conditioning"
patch cords at each end when running LX over multimode fiber. I had
been lucky with not using them for many years on 62.5/125 (OM1)
multimode (and just started doing so again, albiet only for
OOB/non-production traffic use). I believe my longest link was/is
around 1 km.
http://www.cisco.com/en/US/prod/collateral/modules/ps5455/white_paper_c11-463677.html
