Cat-5 or Cat-6 for a gigabit connection

[johningram]

I currently have alot of lines that are running gigabit connections. Switch to switch, switch to work station, and even 2 giga connections connecting our 2 backbones that act as one through the 2 connections.

EVERYTHING is Cat-5. Do gigabit connections require Cat-6 or Cat-5????????

 

[robertjo24]

Cat-5e is rated for gigabit speeds, and will pass if tested for gigabit speeds (if terminated properly).

 

[johningram]

When terminated properly what do you mean? I make strong connections but what do you mean by that?

Also if i used standard cat 5 instead of Cat5e then what would happen? Would it slow down to 100 m/bit?

Also is the length 300ft with giga bit connections just like with 10/100 or is it less or more?

Any info would be nice.

Thanks

 

[robertjo24]

By proper connections, I mean adhereing to p-roper wiring standards (i.e. no more than 1/2" for a full twist).

Ratings are all given for 100 Mteres (330')

I am not sure of the differance between 5 & 5e, but I know 5e is rated for Gigabit speeds. Cat-5 may work, but I don't know if it is rated past 100 Mbit.

 

[buitenhek]

Dear John,
Both the CAT5 and CAT5e have a max frequency of 100 Mhz. CAT6 is 250 Mhz.
As the categorized ratings go up (CAT3,4,5,5e,6) the specifics like: insertion loss, NEXT, ACR, ELFEXT, Return Loss, Delay and Delay Skew get more focused to allow higher speeds. The standards are based on repeatable results (i.e., your test and my test will correlate):
Example:
CAT5 (link type-BL)
NEXT = 29.3 dB
ELFEXT = 17.0 dB
Return Loss = 10.1 dB
Delay Skew = 45 nSec

CAT5e (link type-PL ..was originally BL)
NEXT = 32.3 dB
ELFEXT = 18.6 dB
Return Loss = 12.0 dB
Delay Skew = 44 nSec

In a sense, your system will run at the "lowest common" speed. If you mix CAT5, CAT5e and CAT6 cables, say CAT6 from switch to workststation and CAT5 to other switches, your system throughput will look like CAT5 (100 Mhz)cable only.

Regards
Peter Buitenhek
Profit Developer.com

 

[Servamatic]

It is possible to get Cat 5 when terminated to tight standards to run gigabit.
The difference between 5 and 5e is the number of pairs used, and a slightly tighter twist in 5e.

Cat 5 for 10 & 100 BaseT uses only 2 pairs, Cat 5e for 1000BaseT (gigabit) uses all 4 pairs.

TSB-95 (now obsolete) was a set of tests used to prove whether Cat 5 could run gigabit.

Richard S. Anderson, RCDD

http://www.servamatic.net

 

[Jtodd]

Also, the quality of the components will factor if you can get gigabit over Cat5.

Justin T. Clausen
Physical Layer Implementation
California State University, Monterey Bay

 

[Servamatic]

Very true Justin, but then that is true for 5e and 6 too.

Richard S. Anderson, RCDD

http://www.servamatic.net

 

[Jtodd]

Won't argue there. I think you can 'expect' anything marked Cat6 to run gig, but just barely and I would never be overly confident about it doing so. Particularly down the line when new technologies come out that are 'inteded' to run over Cat6 GigE, but are much more bandwidth intenstive that I would expect stuff that is minimally (to get Avaya's shorts is a bunch: read stuff=ICC and the like) complient to start failing.
Not to stray too far from the original post, being that is was about GigE running over existing Cat5, if the original poster (johningram) is getting GigE over Cat5, I think I would hazard a guess that the existing cable was not minimally complient at the time of install (ie higher end cable and connectivity). But that's just a guess on my part, and would be why I like to install the best stuff I can.

Justin T. Clausen
Physical Layer Implementation
California State University, Monterey Bay

 

[johningram]

Well currently we are running gigabit over cat-5 and some cat-5e and as far as we know it works. But we dont really have any real way to test it i dont think. How could i test a giga connection from a pc to a giga bit switch?

Also when using grounded cables do you ground one side or both. Obviosly you would assume both but i have been hearing you only want one side connected. Is there truth to this?

 

[Jtodd]

There are software packages out there that will tell you about your network connection and it's quality. I don't know what any of them are called, 'cause I've never used them. I leave that up to the network guys.
There are also test units you could get from like Fluke, but I'm thinking those are close to $10k. If you've got a buddy that has one you might offer him a case of beer to check it out for you.

Justin T. Clausen
Physical Layer Implementation
California State University, Monterey Bay

 

[Ghostin]

Most cable is not minimally compliant. I recently spoke with someone on the IEEE & TIA standards board. They seldom run into standard Cat 5 networks that won't run Gigabit. The advantage of using Cat 6 vs. Cat 5e is more headroom. Meaning less db loss and crosstalk for the same type of install. Probably noticed more when you start talking about 10gigE instead of of GigE.

 

[johningram]

Ok, so cat-5 and cat-5e is fine for gigabit speeds with most networks?

 

[Jtodd]

We just got our new Cat6 tester, and while playing with it, I thought I'd try out a nasty patch cord that we have laying around for a worst case scenario. The cord is a 40ft solid UTP Cat5 cable, with poorly terminated shielded plugs on both ends. So for the fun of it, I ran a Cat6 and Cat5 link test on it. After wiggling it enough for pair 3 to not show open (they weren't actually open), I obviously failed the Cat6 test. BUT as the new testers are want to do, it does show what network protocols that it does meet spec for. And low and behold, but what at the top of the list but 1000BaseT.
So I guess the conclussion is that yes, cat 5 will run gig. But how well it the real question.

Justin T. Clausen
Physical Layer Implementation
California State University, Monterey Bay

 

[Ghostin]

Justin,

You were right on about the quality of components. Since the specs on the cable is linear, and has no baring on speed, the ability to transmit at rated speeds is dependant on the performance of the equipment. One of the marketing caveats of Cat6 is it's projected ability to handle 10gig equipment, and that there is more types of equipment available for 10gig than for gigabit.