Inside plant 10G fiber specs?

Richard A Steenbergen ras at e-gerbil.net
Tue Mar 16 05:39:39 UTC 2010


On Mon, Mar 15, 2010 at 10:15:51PM -0400, Jeff Kell wrote:
> And a follow-up to my original question...
> 
> I'm reading the Cisco SFP GBIC-SH spec for 50u OM3 and it shows a
> rating of 1000m?  Really?  That's better than the LH rating over the
> same fiber (550m)?

Hi Jeff,

I don't know of any optics with a 1km reach over MMF at either 1G or 10G
rates. Over OM3 fiber you can get ~260-300 meters of 10G, over older MMF
you can potentially get much less, it depends on the exact signal you're
trying to pass. Yes you can get 550 meters with 1G LX over MMF, but the
MMF itself is ultimately what is limiting you. I recently did a NANOG
presentation on some of this, you may want to take a look at:

http://www.nanog.org/meetings/nanog48/presentations/Sunday/RAS_opticalnet_N48.pdf

Personally my take on this particular problem is to stop doing MMF runs
and standardize on SMF where possible. If you do any amount of shopping
at all you can find optics for SMF which are barely any more expensive
than optics for MMF, especially if you're only talking about 1GE or 10G
SFP+. The grief caused over the long run by having more installed MMF
plant, especially as you try to move to 10G speeds and beyond, is IMHO
not worth the relatively small short term cost optimization.

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
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