Sign in with
Sign up | Sign in

CAT Fight

Intel’s X-Lab: Tomorrow’s Network Happens Here
By
CAT Fight

CAT5e cabling is very common. I have it running through my own walls for gigabit structured wiring. The cabling specs out at 125 MHz and simply uses four pairs of loosely twisted copper wiring. CAT6 steps up to 250 MHz, features tighter twisting, and adds in a dielectric conduit that separates the four twisted pairs and helps prevent energy from one pair bleeding into its neighbors.  Most 10GBASE-T specifically targets CAT6a cabling, which includes even more stringent control over pair twist, as well as manufacturer-specific design features for improving immunity to alien crosstalk noise.

Pete set 10GBASE-T cabling in historical perspective to illustrate some of the increasing problems networking engineers face.

“10BASE-T has been around for a long time, and it’s even been demonstrated to work over barbed wire. There’s that much signal-to-noise ratio margin, even on a very lossy channel like barbed wire. It’s 6 V peak to peak, best-case, and the pulses are very wide. It takes a lot of bad things happening in the channel for a receiver not to see it.

100BASE-TX requires you to do some funky things to the signal. Instead of the two-level signal in 10BASE-T, there’s a three-level signal. If you look at the signal energy, it’s a 2 V peak to peak system, so there’s less power, but all of this scrambling and pulse shaping gets it to work. In 1998, that all wasn’t very straightforward, but with modern signal processing, it’s pretty easy to do 100BASE-TX.

Now, for gigabit, you start to get into some magic. There is more noise power than signal power, meaning we have a negative signal-to-noise ratio. That means if there’s a lot of background noise—like in this room now—and if we get that hammering noise so loud that you can’t hear me, that’s like a gigabit Ethernet noise environment. In 2000, 2001, there were some signal processing techniques applied, some special encoding and decoding that, at a high level, means you’re taking a best guess. You know what you’re sending out, and the receiver knows that there are certain expected combinations that will be coming back. So the system takes a best guess, to put it crudely, at what that data is. Better than 1 in 10-10 times, it makes the right guess.

But gigabit sucked up a lot of power and required, for the time, a lot of gates. At the gigabit inflection point, you started to have more gates than analog circuitry because we’re sending highly-encoded analog signals—those wiggly things with an amplitude and everything else. To encode and decode that properly requires a lot of logic gates. For 10GBASE-T, you just carry that concept to the next level. If gigabit is a whisper in a rock concert, 10GBASE-T would be like a whisper in a nuclear blast. It’s that much more noise power compared to the signal power. But with today’s digital signal processing techniques, you can make a signal have more apparent power. That’s one way to think of it. Again, the ratio of analog content to gates in 10GBASE-T is—wow. It’s very significant, with much, much more digital than analog content. This is good because it suddenly becomes very Moore’s Law-friendly, plus you get the advantage of power savings as you go to each new process node. In the lab here, we have 90, 60, and 40 nm technologies. The power savings associated with each generation has been key for our 10 Gb NIC products and the broader 10GBASE-T deployment in servers and switches.”

See more See less
Display all 19 comments.
This thread is closed for comments
  • 0 Hide
    dogman_1234 , January 17, 2011 4:05 AM
    Anyone else notice the Guy Fawkes mask in the background?
  • -1 Hide
    super_tycoon , January 17, 2011 6:38 AM
    dogman_1234Anyone else notice the Guy Fawkes mask in the background?


    It's existence is noted in the text for pic3, though I can only wonder why he has it. Is it good taste to associate yourself with 4chan and anon nowadays?
  • 0 Hide
    gmoney86 , January 17, 2011 7:10 AM
    I am not sure if I ever saw the sign to the X-Lab when working at Jones Farm, but I did always wonder what went on in the labs that were similar to it. They kind of looked like IT work rooms to me, though it makes sense to have a need for oscilloscopes, soldering irons, networking tools, etc. for certain R&D projects.
  • 2 Hide
    CvP , January 17, 2011 7:19 AM
    In picture #4 (elephant arm) :D 

    Thanks Toms for this article.
  • 2 Hide
    scook9 , January 17, 2011 2:25 PM
    Awesome article, I just finished me BSEE degree and now work in an network company where I help engineer servers so this is right up my alley!
  • 0 Hide
    Anonymous , January 17, 2011 4:28 PM
    This all started in 1990 with the creation of EtherExpress 16 by a handful of people led by a visionary leader, Steve Kassel.
  • 0 Hide
    williamvw , January 17, 2011 10:30 PM
    super_tycoonIt's existence is noted in the text for pic3, though I can only wonder why he has it. Is it good taste to associate yourself with 4chan and anon nowadays?

    My guess is that it was just a fun-looking mask someone had brought to the lab, perhaps because they also enjoyed "V for Vendetta." (I did!) I'd wager that the X-Lab crew had no idea of the mask's fleeting association with 4chan's anti-Scientology protests, much less the religious motivations behind Fawkes's attempted regicide. Let's not accuse good people without cause.
  • 1 Hide
    chovav , January 18, 2011 10:02 AM
    Excellent article Tom (Willam actually). Nice reading, informative and geeky, just the way I like it. Amazing to see that they transfer 76TB in just one test (500,000,000*1518*100). Good job!
  • 0 Hide
    dEAne , January 19, 2011 12:46 AM
    I love this article - thanks for this info.
  • 0 Hide
    williamvw , January 26, 2011 6:50 PM
    chovavExcellent article Tom (Willam actually). Nice reading, informative and geeky, just the way I like it. Amazing to see that they transfer 76TB in just one test (500,000,000*1518*100). Good job!

    Yeah, I was stunned. I honestly expected some automated tests, maybe a few guys with scopes taking occasional signal readings -- NOTHING like what I saw. I'd assumed that a technology as old as Ethernet was pretty much a done deal and didn't require much hand holding at this point. I couldn't have been more wrong.
  • 0 Hide
    Anonymous , February 1, 2011 8:27 PM
    Does this have a PHY made by one of startups like Aquantia or Teranetics or is it a Broadcom PHY.
    I think we will be running 10GbaseT LOM in most datacenters soon.
  • 0 Hide
    Anonymous , February 7, 2011 3:30 PM
    You can buy them off of newegg, they use Teranetics PHY's (Logo under the heatsink).
  • 0 Hide
    woshitudou , February 12, 2011 12:57 AM
    Can Toms quit with the galleries or add a '10 per page' mode? Clicking next and having the entire page reload 50 times and having to scroll down 50 times is stupid. It's like we're suck in 2001 web design practices.
  • 0 Hide
    juanc , February 25, 2011 3:06 PM
    The question is... where is QAM in networks? Why not? Is there anyone from Toms taking this question?
  • 0 Hide
    rebel1280 , May 18, 2011 4:44 PM
    Fun, great, informative and geeky. Loved reading every second of it. A nod and a drink to those guys for sure! By the way, i have IE9 and i cant post comments with it, have to use firefox for it, just an FYI. Not a big deal as i use FF anyways, just testing IE9.
  • 0 Hide
    quickmana , June 7, 2011 10:09 PM
    I don't know why but the picture of the engineer staring deeply into the glass struck an emotional tone with me.
  • 0 Hide
    Anonymous , November 1, 2011 9:50 PM
    Nice to see a TestEquity chamber in picture number 23!
  • 0 Hide
    faryalk90 , June 25, 2012 9:08 AM
    A very Nice and Helpful Post..Thanks for Sharing
    Samsung Galaxy S II Skyrocket i727

    Samsung Galaxy Nexus

    Samsung I9100G Galaxy S II

    Samsung Galaxy Note
  • 0 Hide
    faryalk90 , June 25, 2012 9:09 AM
    A very Nice and Helpful Post..Thanks for Sharing