Why Certify the Network for Gigabit

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Feb 11th, 2009
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Hi All,

Before we purchase gigabit switches for our network, I want to certify our network wiring to make sure it will support gigabit. Nobody knows for sure if the wires are cat5 or cat5e. The owner of the company says just plug a computer in to a port connected to a GB switch and if it connects at 1GB, then its good. I have had problems with this before and I know that trying to run GB over bad wiring can be worse than just leaving it as 100Mb. However what I am having trouble with is finding documentation to support that. Can anyone help me out by posting some links explaining why you have to test your wiring? Thanks!

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scottmac Wed, 02/11/2009 - 15:42
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I don't have any specific documents, but I believe the core argument is essentially "Why are you spending the money on gigabit if you can't guarantee optimal performance?"

In other words, failing to qualify your cable plant reduces the chances that your cabling is permitting the best possible efficiency (isn't that why you spend the money?)

Also, "plug it in, if it works, it's ok" is a fallacy ... you can get data through barb-wire fence, but it won't work as well as category-rated UTP cabling (IOW: you can use a VW Jetta to haul 20 tons of racks in the back seat too, but there's better ways to do it).

"Works" (does not equal) "working at best performance."

The tolerance for wasted time & money (keeping in mind potential network troubleshooting issues) is strictly dependent on your company's policy.

Good Luck


Leo Laohoo Wed, 02/11/2009 - 16:02
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To have the cablings tested means that some independent 3rd party can guarantee that your cabling meets the approved standard, in this case, for GigabitEthernet. A mentality of "just plug a computer in to a port connected" means he/she either don't care or don't know.

Why certify the network for Gigabit? Well the common argument is that we are entering a new phase where Multi-Media streaming, VoIP Phones, PoE and VMware are common catchphrases. Anyone of these applications alone can chew up 10/100 Ethernet bandwidth quickly. Servers need Gigabit because of the amount of data being transfered.

Does this help?

grplante Mon, 04/06/2009 - 07:44
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Check out the following link for information of the differences between Cat5 and Cat5e.


I my experience I would not use anything less than Cat5e UTP for GB applications over longer runs. At this time we are trying to standardize on Cat6 cabling for the users. Until this happens we are limiting all of our user connestions to 10/100 auto neg.


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