Question about Ethernet cables

[unnamedplayer]

Hi all, I've been doing some reading about networking and physical media and I was reading about different categories of UTP cable (Cat 1-6) and something I'm having a hard time understanding that the book didn't explain too well is the difference between MHz and Mbps.

For example, the book I'm reading says that Cat 5 is rated for 100MHz and then it says that Cat5e is also rated for 100MHz, but can handle gigabit ethernet. This means that Cat 5 and 5e each are 100MHz, but 5e can handle 1000Mbps while Cat 5 only does 10/100Mbps correct?
How so if both are 100MHz?

Also, one other question. The book says to use 5e as the minimum when installing cable because some cables are now certified for 350MHz or beyond which allows the cable to exceed speeds of 1Gbps. So, I'm wondering is the author referring to Cat5e cable that can do 350MHz (b/c earlier as I mentioned he said it was rated at 100MHz)?

Any help is greatly appreciated!

 

[spidey07]

When talking cables, you have to read through the marketing "fluff"

The thing with gigabit ethernet is each pair uses 250 Mbs to achieve gigabit rates.

The Mhz is the "bandwidth" that the cable was tested to and still be within the specifications for other properties of the category rating system. If you look at category rated tests for cabling you'll see that they start to fall out of specification the higher you go.

With all that being said, gigabit ethernet will run just fine on cat5e. And nobody in their right mind would be installing cat5e in this day and age. It is mearly an extension of cat5 that has been around for 10 years.

Bandwidth is an analog measurement in MHz.

Mbs is a digital measurement taking into account the the way you transmit bits and overall throughput from one end to the other. For example - 100 Base-T actually is a 125 megabaud technology...so even though the serialization is 125 megabaud serial, the actuall throughput is 100 megabits/sec.

Hopefually our resident cabling guru ScottMac can enlighten us.

Go to www.anixter.com for all kinds of good information. Just be sure to wade through the "marketing fluff."

 

[mikeford]

Just a quick guess, but I think its like saying USB 2 also supports USB 1 etc. Cat5e meets a HIGHER spec, but also supports the older slower spec. of 100 mhz.

Cat5e is the only thing ya wants to pay for or put in a perm install. Patch cords etc. I would just use whats handy and what works.