In this blog post, Douglas Boom from Intel attempts to claim that bending of Category 6 cable doesn’t cause failures of 10 Gigabit Ethernet. Wrong!
First up, bending the cable. I was at a trade show and a gentleman comes up and says to me “That 10 Gigabit stuff is for the birds, you can’t even bend the cables without dropping link!” …SNIP…..“I think you’re mistaken, sir.” I said. He smiles and reaches behind my demo and grabs the cable. He bends it over on itself, making the straight run into an O shape. He pushed with his thumb and made into more of an I shape. He let it go and walked over to the console screen, expecting error message after error message of disconnected link. To his shock, (and my amusement) nothing happened. “Wow.” He mumbled. He took my card and left the show floor, all the while being heckled by his travel buddies. Unless you damage the cable, I’ve never seen a bent cable effect link. And I’m not gentle to my cables.
It’s possible that data carried over the signal over that cable might not be affected. There is a significant likelihood that the cable will fail later due to temperature variations or other physical events eg. jamming it in the door. Once mechanical trauma has occurred, the cable has degraded signal performance. If there are other signal losses, such as interference, or bad connectors, secondary mechanical trauma, then the cable might fail immediately. More likely it will fail at some point in the future when no one remembers why the cable is now failing.
Modern cell phones and modern 10 Gigabit BASE-T are both designed to use as little power as needed to reach the end station so you would have to be pretty close with a very powerful cell phone to put a ton of noise onto the wire. And we do test cell phone interference, but with good cables you shouldn’t see any issues. Use bad cables and things could get ugly. Good cables include shielding to protect signal wires from disturbers. Those DSPs can only filter out so much; an investment in quality cables is an investment in the quality of your data.
I completely disagree with the use of shielded cabling. It’s true that shielding can further improve noise injection, however, current cabling designs use twists to reject most of this noise. And of this was a problem then most networks wouldn’t be working today. In my experience, shielded cabling costs far more than the risk profile, and typically causes problems due to faulty shield earthing.
The EtherealMind View
Cabling is hard. Take time to learn about it and understand physical signal propagation in a copper medium.
Cable shielding has been comprehensively proven as useless over the last 20 years of the network cabling. Don’t even consider it. It’s nothing but pain in so many different ways.
Damaged copper cores causes intermittent faults and they are the very worst kind of faults.
I’ve talked about this before: Problems With Cat6A Cables in Data Center. Nothing has changed. 10GbE over copper isn’t the best idea for reliability.