CAT5 or CAT6?

[bobby62]

Hi Guys,

What is the main difference between CAT5 and CAT6 cabling. What would you suggest in a small office of ours?

Thanks

 

[peterduckett]

Well;

Cat 5 is rated to 100Mbps
Cat 5e is rated to 1000Mbps
Cat 6 is rated to 1000Mbps with significantly lower NEXT and PSNEXT or possibly 10 Gbps over 37m where the chance of of alien interference is minimised
Cat 6a is rated to 10Gbps
Cat 7 is unratified to 40 Gbps and only available as STP cable

 

[bobby62]

Well;

Cat 5 is rated to 100Mbps
Cat 5e is rated to 1000Mbps
Cat 6 is rated to 1000Mbps + with significantly lower NEXT and PSNEXT

Many thanks, what is NEXT and PSNEXT?

 

[peterduckett]

layman's terms it is the amount of accepted crosstalk near and far end before data transmission falls down and needs to be resent

 

[bobby62]

Excellent, thanks guys

 

[kjacko]

Bear in mind that cat6 has a wider radius criteria when bending the cable around things like architraves etc, wherease cat5e cat be almost tied in knots and will still give gigabit speeds, at least for the run a house would require.
Cat6 is thicker and stiffer (usually).

 

[plugwash]

Cat 5 is rated to 100Mbps

1000BASE-T was originally designed to run over CAT5 but AIUI they later discovered that some important performance parameters had never been specified so while 1000BASE-T will nearly always run over cat5 it could not be guaranteed in the worst case.

CAT5 isn't generally sold anymore though so it's not an option in consideration for a new install.

Cat 5e is rated to 1000Mbps

Right.

Cat 6 is rated to 1000Mbps with significantly lower NEXT and PSNEXT or possibly 10 Gbps over 37m where the chance of of alien interference is minimised

That was my understanding, we will have to wait to see how it pans out in practice when 10GBASE-T becomes more common (afaict right now most 10 gigabit stuff is run on either fiber or SFP+ direct attatch)

Cat 6e is rated to 10Gbps

It's 6a not 6e

Right now CAT6a seems to be about twice the price of cat6 and I suspect to actually acheive CAT6a performance is going to require very careful termination driving up installation costs.

Cat 7 is unratified to 40 Gbps and only available as STP cable

AIUI while some cables have been marketed as CAT7 there is no such category within the standards that define the network cables we use. It remains to be seen what form a 40 gigabit ethernet over copper standard will take if one ever exists.

Personally I think for a normal office gigabit ethernet to the desktop will be sufficient for many years to come so there is little point installing anything higher than cat5e for links to the desktop.

 

[peterduckett]

Cat 5 is rated to 100Mbps

1000BASE-T was originally designed to run over CAT5 but AIUI they later discovered that some important performance parameters had never been specified so while 1000BASE-T will nearly always run over cat5 it could not be guaranteed in the worst case.

I'm guessing that if the OP doesn't know the difference between cat 5 and cat 6 he most probably lacks the test equipments to ensure 1000Mbps so will have to install on the understanding of 100Mbps.

Cat 7 is unratified to 40 Gbps and only available as STP cable

AIUI while some cables have been marketed as CAT7 there is no such category within the standards that define the network cables we use. It remains to be seen what form a 40 gigabit ethernet over copper standard will take if one ever exists.

Thank you for explaining unratified

 

[ban-all-sheds]

AIUI while some cables have been marketed as CAT7 there is no such category within the standards that define the network cables we use.

Not strictly true.

There is a standard - ISO/IEC 11801 Class F and Class FA. They may not be recognised by TIA/EIA, but they exist alright.


http://en.wikipedia.org/wiki/Category_5_cable

http://en.wikipedia.org/wiki/Cat6

http://en.wikipedia.org/wiki/Category_7_cable

http://www.google.co.uk/search?q=cat+8+cable

Personally I think for a normal office gigabit ethernet to the desktop will be sufficient for many years to come so there is little point installing anything higher than cat5e for links to the desktop.

The one constant in IT is that predictions along the lines of "xxxx will always be enough" are always wrong.

It's an office - should be professionally done - might as well put in 6a.

 

[jabuzzard]

The one constant in IT is that predictions along the lines of "xxxx will always be enough" are always wrong.

It's an office - should be professionally done - might as well put in 6a.

Yeah, and pray tell me what you are going to do with 10Gb to the desktop? I can tell you know from the experience at work, getting servers to actually max out 10Gb Ethernet is far from simple. The only thing we could think of was streaming a 4K TV picture uncompressed, and that would be a pretty dumb thing to do anyway (better to ship the compressed source and decode locally).

Cat6 won't cut the mustard for 10Gb if you have lots of bunched cables. We had it tested at work, whole data centre of structured wiring to the top of the rack does not cope. On the other hand the much smaller bundles I have at home (yep full structured wiring in Cat6), with less rigorous testing (just two switches borrowed from work one weekend) showed that at least some 10Gb links will work and pass traffic at 10Gb. On the other hand 1Gb Ethernet is slower than a local hard disk, so is definitely reaching it's sell by date.

if you are purchasing the cable buy Cat6a. Even if you do DIY terminating and make a pigs ear provided you leave some slack you can always get it professionally terminated should you actually want to do 10GbT in the future.

My understanding is that no attempt is going to be made to do 40Gb or 100Gb Ethernet over copper. Does not surprise me as QDR Infiniband cables are a pig to work with, fibre optic cable is much easier.

 

[ban-all-sheds]

Yeah, and pray tell me what you are going to do with 10Gb to the desktop?

Yeah, and pray tell me what you are going to do with more than 640KB in a PC?

1Gb Ethernet is slower than a local hard disk, so is definitely reaching it's sell by date.

if you are purchasing the cable buy Cat6a.

might as well put in 6a.

 

[jabuzzard]

Yeah, and pray tell me what you are going to do with 10Gb to the desktop?

Yeah, and pray tell me what you are going to do with more than 640KB in a PC?

I think you miss the point, which is at some point there is limit at which you don't need more of said quantity in computing for ordinary usage.

So if your computer had 640TB of RAM that would be an amount of RAM that nobody is ever going to need on a desktop. If you can come up with a use for it let me know.

Just to make the point a bit more blunt a 128bit anything; RAM, disk capacity etc. has more storage space than there are atoms in the universe.

Just because someone made a comment that is misquoted some 30 years ago and in it's misquoted form looks daft today does not mean that the curve will continue for ever.

 

[ban-all-sheds]

I think you miss the point, which is at some point there is limit at which you don't need more of said quantity in computing for ordinary usage.

I think you miss the point, which is that predictions along the lines of "nobody will ever need more than xxxxxx of yyyyyy" are so often wrong that you'd think intelligent people would shy away from them.

So if your computer had 640TB of RAM that would be an amount of RAM that nobody is ever going to need on a desktop. If you can come up with a use for it let me know.

Give Microsoft bloatware a few more years...

Of course it's easy to pick an enormous number like 640TB and say the nobody will ever need that much, but that example is less of an issue than a cabling infrastructure choice between existing capabilities. 640TB is addressable by a 64-bit architecture, but nobody does it yet, I'm not aware of any monolithic systems which offer that much RAM, nor any OSs which support it. But to say "never"? History is not on your side.

How many years ago (not many) would you have been branded a loony if you had predicted that there would be a substantial market for portable HDDs with capacities in the TB range?

Just because someone made a comment that is misquoted some 30 years ago and in it's misquoted form looks daft today does not mean that the curve will continue for ever.

So far the curve is continuing.

 

[JohnW2]

Just because someone made a comment that is misquoted some 30 years ago and in it's misquoted form looks daft today does not mean that the curve will continue for ever.

You're right - BUT not only are the curves still very much alive and well, but they are actually still increasing in upward slope. For the forseeable future, you're therefore on very dangerous ground if you deny that considerable further increases are not only likely, but are actually virtually inevitable, before any flattening of the curves is likely to be seen.

We're talking here about transmission speeds. One does not have to be anything like as old as me to remember the time when it was generally thought that speeds greater than 9,600 bps (0.0096 mbps) would be physically impossible via the PSN telephone network.

Kind Regards, John