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RE: Question on Fiber for 10Gig



Chris,

A common mistake people make is confusing the 802.3ae objectives with the operating ranges over each fiber type. To clarify, the 802.3ae distance objectives are to support:

65m over MMF (cost optimized for short distance)
300m over installed MMF (defined as 160/500 MHz.km 62.5um fiber)
2km over SMF
10km over SMF
40km over SMF

I am attaching a Table that summarizes the operating ranges for 850nm Serial solutions and 1310 WWDM solutions over each of the fiber types. The short answer is that:

*	You can support 300m over installed 62.5um fiber with 1310 WWDM (500MHz.km)
*	You can support 28m over installed 62.5um fiber with 850nm Serial (160MHz.km)
*	You can support 300m over installed 50um fiber with 1310 WWDM (500MHz.km)
*	You can support 86m over installed 50um fiber with 850 Serial (500MHz.km)
*	You can support 300m over 50um fiber with 850 Serial (2000MHz.km)

Cheers,

Steve

 <<Distance table.pdf>> 

> ----------
> From: 	Chris.Kozup@metagroup.com[SMTP:Chris.Kozup@metagroup.com]
> Sent: 	Monday, November 13, 2000 5:49 PM
> To: 	stds-802-3-hssg@ieee.org
> Subject: 	Question on Fiber for 10Gig
> 
> 
> Hello,
> 
> I am looking at a white paper on 10Gigabit Ethernet which is
> published on the 10GEA website.  Within this document it lists
> the plans for Multimode and Singlemode support of 10Gig.
> 
> According to this document, 50 micron Multimode Fiber will only
> be specified to run up to 65 meters using an 850nm PMD.  Whereas
> a 62.5 micron Multimode Fiber will support 10Gig up to 300 meters
> using a 1310nm PMD.
> 
> Does anyone know why this decision was made as such ?  More
> specifically, my understanding was that a 50micron fiber was of
> better quality compared with a 62.5 micron.  Why not include a 50
> micron standard for a 1310nm PMD ?
> 
> any comments appreciated.
> 
> thanks
> 
> Chris Kozup
> 
> 
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Distance table.pdf