# Will cat 5e run a gigabyte LAN?



## SPL Tech (Aug 23, 2006)

Is cat 5e good enough for a 1,000 Mbps network or do I need cat 6 to get a full 1 Gbps of data transfer? The total run is about 20 feet. Also whats the limit of cat 5e?


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## JohnWill (Oct 19, 2002)

Yes, in truth CAT5e will handle gigabyte connections of the full specified maximum length, around 93 meters.


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## jmwills (Sep 28, 2005)

Yes indeedy. My LAN is living proof, at least when Telecom is gracious enough to keep my DSL connection alive!!


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## JohnWill (Oct 19, 2002)

I have CAT5e all around, and I have gigabyte connections at the end of about 120 feet of CAT5e, no sweat.


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## SPL Tech (Aug 23, 2006)

But will you see data transfer speeds of 1,000 Mbps with cat 5e? I am being told that cat 5e's limit is about 350 - 400 Mbps of actual transfer speed and cat 6 is limited to about 600 - 700 Mbps of actual transfer speed.


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## JohnWill (Oct 19, 2002)

Yep, you'll see full speed. The modulation isn't at a gigahertz, but rather 125mbits. Also, gigabit connections use all eight wires in the cable, 100mbit connections only use two pairs. You was told wrong. 

[WEBQUOTE="http://www-cse.uta.edu/~gcarrick/Stuff/LOVE-GIG.HTM"]Gigabit Bandwidth over Category 5 Cabling Fast Ethernet (100BASE-TX) achieves 100 Mb/s operation by sending three-level binary encoded symbols across the link at 125 Mbaud. (A 125 Mbaud symbol rate is required because 100BASE-TX uses 4B5B coding.) 100BASE-T uses two pairs (sic): one for transmit, one for receive. The next step up in speed, 1000BASE-T also uses a symbol rate of 125 Mbaud, but it uses all four pairs for the link and a more sophisticated five-level coding scheme. In addition, 1000BASE-T sends and receives simultaneously on each pair. Combining 5-level coding and 4 pairs allows 1000BASE-T to send one byte in parallel at each signal pulse. 125 M symbols/second X 1 Byte (across four pair)/symbol = 1 Gb/s. Of course, it isn't quite this simple. In addition to moving the symbols across the link, 1000BASE-T must also deal with the effects of insertion loss and link-induced interference caused by echo and crosstalk.[/WEBQUOTE]


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