Fundamentals of NBASE-T

Prepare for 802.11ac Wave2:

TechWiseTV’s Robb Boyd gives you this up-close, engineer’s eye view of the innovative ways Cisco is incorporating the latest NBASE-T technology into its solutions so you can get speeds of up to 5Gbps over your existing Cat5e and Cat6 cable investments.

Find out what you’ll need to get all the bandwidth your users demand today without having to replace any of your current copper cabling.



Robb Boyd: You know, when I was a kid, I loved jumping ramps on my bike. But I got hurt a lot. I always had trouble judging the actual speed versus the height and the distance.

A different kind of mobility has taken off these days, ’cause we love and we demand our wireless access. In fact, demand for 802.11ac WAVE 2 wireless access points is accelerating because it is so incredibly fast. At a published rating of 6.8 Gbps, these are now faster than the network cables that they depend on.

Now in reality, they’ll be looking for two to four GB on the physical interface, but that’s still a bottleneck when you talk about the access switches that are maxed out at one gig.

So what do we need to do? Deploy ten-gig switches? That’s quite a jump when you consider all the new cable you would need. ‘Cause what is it? 300 to 500 bucks per drop to rerun cable? Well, that’s gonna add up quick–hundreds of thousands of dollars of quick. All to support faster access points and those demanding users.

It was bound to happen. I mean, just look at the cycles. Wireless is upgraded every three to four years. Switches tend to stick around another four to six years. Cabling? That’s a 15- to 20-year upgrade cycle…if it ever gets upgraded! Yes, cabling investments are made well before the walls even go up, So you’re most certainly running CAT5e or CAT6 these days, which means you’re maxed out at one gig, with 1000 baseT on 100 meters of structured cabling. This stuff’s probably gonna be here until the walls are torn down.

You know, even if you do work it into the budget, I mean, lets be honest about the business disruption: Some of you guys are in industries that aren’t even allowed to open the ceilings again. So how did this happen?

Well ethernet advances have always come in at ten times the performance for three times the initial cost. So ten, 100, 1,000 BASE-Ts have all been relatively easy jumps to make. But now we’re staring at 10,000 or 10G BASE-T.


Well long jumps need bridges. No, not a network bridge. I was being metaphorical. One is not enough, ten is too much right now. We need something in between that could still use those existing cables. Well the Nbase-T Alliance has been working on this, building the ecosystem and the consensus that we need for 2.5 and 5 Gbps Ethernet standard. It makes a lot of sense and can save us a ton of money.

But how’s it all done?

Well, it’s the frequency, Kenneth. We can always increase speed by increasing the frequency, but only to a point. Higher frequency generate more noise, or EMI, electromagnetic interference. This is why our cabling is both shielded and twisted. Tighter twists and better shielding are required for the higher frequencies that a company each increase in bandwidth. So for a given distance–100 meters for Ethernet–you want the minimum frequency needed to hit your rated bandwidth.

Well the engineers working within the NBASE-T alliance figured out how we could do this for real. And they found more room to play with the full 100 megahertz that CAT 5e can handle and increased the code density to get us to to 2.5 gig. Then moving up to 200 megahertz gives five gig inside the CAT6 limits. And then, well, 10G uses 400 megahertz. So that’s still gonna be on your CAT6a cable.

Well, this is not theoretical stuff. You can do this right now with Cisco Catalyst multigigabit switches. These will automatically select the maximum link speed for you, supporting both the 1- and 10-Gbps standards, along with the NBASE-T alliance specs for 2.5 and five. And all of this from the same POE switchport, be it PoE, PoE+, or even universal POE.

So unless you’re cabling a new building or doing some substantial remodeling, don’t stress too much about trying to make that big jump. Upgrade a switch, don’t buy a new building. ‘Cause we live in a mobile world, and that mobility demands multigigabit access that won’t slow it down.


Duration: 4:7
Publisher: Cisco
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