Book states that Cat5e can deliver 1000BaseT at 100m. Is the book wrong?

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Apr 17th, 2008
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Interesting. I always believed that Cat5e main limitation was the lack of 1Gbps support (and if possible to deliver Gbps, then the 100m distance would be decreased).

Someone showed me a book today stating

that Cat5e can deliver 1000BaseT at 100m

Is this book wrong?

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exonetinf1nity Thu, 04/17/2008 - 07:52
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Yes Cat5e can fully support 1Gbps over 100m's although i would generally keep cable lengths to 90m or less if possible.

news2010a Thu, 04/17/2008 - 07:54
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Well, so what's the limitation of cat5e compared to cat6 then?

a.cruea1980 Thu, 04/17/2008 - 08:04
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The main different is the twists per inch, which decrease cross-talk and interference.

The cost, too.

scottmac Thu, 04/17/2008 - 08:44
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Straight Cat5 can carry gigE just fine, and it's minimum spec for Gig.

Cat5e is better, in that all pair are qualified for high-speed data (versus Cat5 where only the Orange and Green pair are qualified).

Cat6 Is OK (overkill actually), but gives you some "futurproofing" for 10GigE over copper and other complex signaling (remember that this all related to "Structured Cabling" systems, which are for more than Data Networking).

Cat6a (Augmented) extends the desired qualities for things like 10GigE over copper and "beyond."

The 568 specifications (for up to GigE anyway) are for 100 meters (328feet) total, end-to-end, which includes 90 Meters of solid-core "in the wall" cabling with up to 5 meters of stranded "jumper cordage" at either end.

Stranded is not recommended "in the wall" (or really long runs) because it has higher attenuation than solid-core cabling.

Solid-core cabling is not recommended for Jumpers, because it does not flex well (breaks easier and flexion moves the paris around and kills the propagation characteristics of the cable)

The primary advantages of going "above spec" for cabling is that it MAY provide some additional headroom , and extends the likely time of usefulness for the cabling plant.

Good Luck


dave.keith Thu, 04/17/2008 - 12:20
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The only 'real' books on ethernet are the IEEE 802 specifications (sorry Robert). To the best of my knowledge these spec's do not make any mention of a length of cable. They do specify the electrical charactoristics like total loss at 1MHz (or something like that). From these electrical specifications a 'rule of thumb' (100 meters) has been created.



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