Cat6 vs Cat5 - what should we be using...

[DoFoT9]

had a nie big long reply but my router conked out and made me loose my page when it went to the error page! ugh

I ran a test on a corporate 10/100 Cat6 network and here is what I got:

Downloading a file from server to my system over Cat6: 95,875 kbps which is 11.70349MBps. That translates to 93.62792 Mbps, 6.37208 Mb shy of capping 100Mbps.

good results, shows that it can happen

If you ignore overhead and have hard drives on both ends capable of sustaining those speeds, you still won't reach 100 Mbps (or 1 Gbps if that's what you're using). You may come close, but there is always going to be something preventing it, whether it's outside noise, a slight defect in the cable, etc. Perhaps if you stuck the entire network inside a faraday cage so there's no outside interference, and built a high quality, extremely expensive cable you could peak out at 100 Mbps, but in the real world, there is always a limiting factor.

i am not sure about the failure rate of data sent because of 'interference' in the average building, but i doubt it would be limiting it by what you are saying. maybe 20%?

Hard drive speeds are half the problem. Again, take overhead out of the equation and assume you have hard drives capable of reaching those speeds. You still won't. USB 2.0 bursts, meaning it transfers at a slower speed, occasionally bursting up towards 480 Mbps, but the average speed over a transfer would still be much lower. Firewire is sustaining, meaning it starts transferring at a higher speed and stays around that speed for the length of the transfer. Even then, it will never quite get up to 400 (or 800) Mbps, but that is why people claim that Firewire 400 is better than USB 2.0 even though USB is faster on paper, because average transfer speeds during a transfer tend to be higher.

lets not get into those other intefaces, id rather we keep it purely ethernet based.

Misleading? Yeah, but we've become used to it, just like the whole 1,000 vs 1,024 bytes in a kilobyte for hard drive sizes.

no, not misleading at all. you're not exactly talking to a git here

I don't have any tests, just a Cisco network certification which means I've studied this and know what I'm talking about, or at least I have a piece of paper from Cisco that says I do

i have a few M$ networking certificates and the like, but eh - what do they even mean?

This thread cracks me up.

In networking, the best you can have in actual speeds is 80% of the theoretical. The reason behind this is because before and after each byte sent, there is a starting and stopping bit. With 8 bits in a byte, that equates to 10 bits sent for every byte, or 80% efficiency.

i dont think that we are referring to the physical layer here, but rather the link layer.

question::when observing the 'transmission rate' of data (e.g. copying files over two computers on the same network) does it include header data etc or is it not included in the rate? if it was included, then there is basically little overhead. of the latter, then yea- there would be more overhead.

 

[yg17]

i dont think that we are referring to the physical layer here, but rather the link layer.

question::when observing the 'transmission rate' of data (e.g. copying files over two computers on the same network) does it include header data etc or is it not included in the rate? if it was included, then there is basically little overhead. of the latter, then yea- there would be more overhead.

What the OS tells you is without any overhead. If you transmit a 1 megabyte file to another computer, more than 1 meg of data actually gets transferred. So if you have a 100 Mbit link, even assuming it can actually sustain a 100 mbit transfer, and hard drives at both ends could read/write that quickly, you'll never see a 100 mbps transfer rate in your OS for the simple fact that the 100 mbps link includes packet overhead, the OS does not. 100 mbps may go over the line, but 80 mbps may be all the OS can really use due to overhead.

 

[DoFoT9]

What the OS tells you is without any overhead. If you transmit a 1 megabyte file to another computer, more than 1 meg of data actually gets transferred. So if you have a 100 Mbit link, even assuming it can actually sustain a 100 mbit transfer, and hard drives at both ends could read/write that quickly, you'll never see a 100 mbps transfer rate in your OS for the simple fact that the 100 mbps link includes packet overhead, the OS does not. 100 mbps may go over the line, but 80 mbps may be all the OS can really use due to overhead.

ok sweet that makes perfect sense.

technically then - 100mbps of throughput is possible, not of actual data, (the overhead is necessary and cannot be avoided) - according to your scenario anyway.

 

[betancourt]

Cat6 better

Quick answer: Go with Cat6. It's worth it and almost costs the same

Long answer:
Cat 5e: Cat 5e cable is the extension of Cat 5 with the same data rate 100 MHz. Most of the specifications of Cat 5 are improved in Cat 5e like PSELFEXT (Power Sum Equal Level Far End Cross Talk), Attenuation and NEXT (Near-End Cross Talk). Cat 5e may be used for 10Base-T, 100Base-T2, 100Base-T4, 1000Base-T and 100BaseTX Ethernet.

Cat 6: Cat 6 cable has a bandwidth of 250 MHz and is backward compatible with the lower categories. It supports the same Ethernet standards as Cat 5e and quickly replacing Cat 5e.

There is more information here:
http://www.serverracksandcable.com/what-is-this-category-cat5-cat6-wire-stuff-about.phpCat6

 

[DoFoT9]

nice explanation betan, its always good to have updates on the things you know. does Cat5e also support 10,000Base-T?

 

[nullx86]

tl;dr

Cat5e is the standard cable choice, also the less expensive one. It can do Gigabit (100/1000) but I can tell you right now that Cat6 is more suited for the job. Personally, if I'm going to wire a house, I would wire Cat5 because its cheaper. Right now I got a few Cat5 lines that run through the house (on the floor, along base boards) and they do their jobs. Once Cat6 becomes the standard, along with Gigabit routers, Ill switch.

Also, someone said interference? If you wire your house (or just drop some internet lines on the floor for that matter) you want to keep them separated from the electrical lines by about a foot or two. You do that and you reduce the amount of interference you get from the electrical lines, and the amount of signal lost from the interference as well. Same should be done with phone/data lines.

 

[koruki]

I did a lot of reading on this before going out to buy cables. I had a Cat5e cable and did some test but was only getting similar speeds to the cat5. I went out and bought a cat6 plugged in between the same connection (Device - gigabit switch - device2) and I hit a peak of 110Mbytes per second. I transfered a 2gb file in under a minute and also able to stream 1080p videos over the network without a hiccup.

So regardless of what I read about cat5e being the same as Cat6, my hands on test shows the cat6 worked as soon as I plugged it in.

 

[DoFoT9]

I did a lot of reading on this before going out to buy cables. I had a Cat5e cable and did some test but was only getting similar speeds to the cat5. I went out and bought a cat6 plugged in between the same connection (Device - gigabit switch - device2) and I hit a peak of 110Mbytes per second. I transfered a 2gb file in under a minute and also able to stream 1080p videos over the network without a hiccup.

So regardless of what I read about cat5e being the same as Cat6, my hands on test shows the cat6 worked as soon as I plugged it in.

nice test! good results! 1080p direct rips only need 5MB/s max, so that doesnt really count as a test lol