concerned about fiber length

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Jun 24th, 2008
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I have a 6509 connected to a 6506 with SFP gbics, glc-sx-mm. The distance between the 2 is about 1350 feet. Is this within specification? Will I have any problems due to the length?


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Overall Rating: 5 (2 ratings)
vmiller Tue, 06/24/2008 - 08:51
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According to spec, I think not. SX multi mode should run to a max of 550 meters, This converts to 1804 feet. Its close.

Do test your light levels first and make sure you have adequate recieve power.

DARYLE DIANIS Tue, 06/24/2008 - 10:20
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hi thanks for the info, is there a document that you can refer me to with the spec? Is it an industry thing or a cisco thing? this line also has 3 connections along the way, so I'm also reading about insertion loss. If you count the fiber patch cords, there are 5 of these connections. I had the fiber tested last weekend and I'm waiting on the results.


Tom Randstrom Tue, 06/24/2008 - 18:03
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The attached document outlines the general rules for estimating the end to end fiber link loss.

The following link is to the Cisco SFP specifications showing 550m as the max distance over multimode fiber with the SFP.


DARYLE DIANIS Wed, 06/25/2008 - 06:45
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thanks, this is good, too, there seems to be a difference in the lenght limit based on whether or not the fiber is 50 or 62.5 micron. I'm pretty sure I have the 62.5, so I could be way over the limit.


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