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The Truth About 802.11ac: Dispelling The Myths

It's official: The next generation of enterprise WiFi has arrived. 802.11ac provides better signal and coverage for lower cost than 11n, despite the doubters.

The uptake of the new 802.11ac standard appears to be occurring much faster than that of its predecessor, 802.11n. Still, you might be wondering if you should start migrating today or wait for the next wave of 802.11ac products, which are expected to arrive in late 2015. There's also the potential of a third wave at some point. When do you make your move?

Unfortunately, the waters are murky. There is a lot of misinformation regarding current 802.11ac products, but a quick debunking of some myths can help you make a more educated decision.

Myth 1: 802.11ac performance advantages are minimal
On paper, 802.11ac has wider channels and better modulation for up to three-times faster speed than 802.11n. It also offers technology like beamforming for more reliable connectivity at greater distances. But what about real-world performance?

Take the example of a smartphone, which uses only one spatial stream. Previously, a smartphone with 802.11n could connect at about 75 Mbit/s. Now, a smartphone with 802.11ac can connect at 433 Mbit/s offering real-world speeds of about 250 Mbit/s.

For a first-hand perspective, I contacted Yale University's IT department. Yale has more than 6,700 802.11n access points (APs), connects about 45,000 wireless users, and has started to deploy 802.11ac.

"We've seen very impressive performance results with our 802.11ac clients, but we were really surprised to see performance improvements with older 802.11n clients as well," says David Galassi, director of IT at Yale.

Yale has big plans for campus-wide 802.11ac and is targeting a new building for an 802.11ac-only deployment. "Our new 242,000-square-foot Edward P. Evans Hall will be our first building to leverage all 802.11ac," Galassi told us. 

Myth 2: 802.11ac requires ripping and replacing my wired infrastructure
Current 802.11ac APs will work just fine with today's Gigabit Ethernet infrastructure. The combination of multiple devices, connected at different ranges and sending mostly TCP traffic, means that throughput on the 802.11ac AP won't exceed 1 Gbit/s very often.

In some unusual scenarios, organizations might push up to 1.2 Gbit/s to the AP, but the added cost of a second cable usually outweighs the rare 10 to 20 percent performance boost.

While this covers the first wave of 802.11ac, enterprises will need to upgrade their network infrastructures to something faster than Gigabit Ethernet when the second wave of 802.11ac arrives in late 2015.

Power is another consideration. The good news here is that many of today's 802.11ac APs will work just fine using the standard 802.3af PoE that your switches already likely support.

Myth 3: Not many 802.11ac clients are available
Hundreds of 802.11ac clients are already certified by the WiFi Alliance, including the Apple MacBook Air, HTC One, and Samsung Galaxy Note. Samsung recently announced that it has sold 40 million 802.11ac-capable Galaxy S 4s. In fact, you cannot buy a laptop today from Apple that doesn't have 802.11ac built in. 

Better yet, all the 802.11ac clients that connect to your network today will improve everyone's experience, because WiFi is a shared resource. 802.11ac clients transmit data faster, using less airtime and allowing more clients to connect per wireless AP.

Myth 4: 802.11ac is 5 GHz only and leaves 2.4 GHz clients stranded
It's true that 802.11ac only works on the 5 GHz radio band, but that turns out to be a good thing. The 5 Ghz space has far more spectrum available and less interference. Just moving more devices to this spectrum will have network-wide benefits.

And have no fear: The 802.11ac radio in your AP is backward-compatible with 802.11a and 5 GHz 802.11n devices.

Also, most 802.11ac APs come equipped with built-in 2.4 GHz radios to connect your 802.11b/g/n legacy devices. Overall, backward compatibility is not an issue with 802.11ac.

Myth 5: The first wave of 802.11ac will be short-lived
Newer, more improved technologies always emerge on the horizon, but we don't expect the first wave of 802.11ac to fizzle out quickly. Unlike a smartphone, you don't completely dispose of one WiFi standard to adopt the other. WiFi allows a gradual migration path.

Because WiFi tends to be backwards-compatible, you can take a mix-and-match approach. Always use the latest standard, and when something else comes out, simply make the right adjustments based on capacity needs.

It makes sense to put 802.11n APs in low-density locations today and deploy 802.11ac in high-density areas. In a few years, you can use the same approach by moving the first wave of 802.11ac APs into low-density areas and deploying second-wave 802.11ac APs in high-density locations.

Excellent management tools are available that can show you the real-time utilization metrics of any AP on your network. These metrics will enable you to determine where your highest-density WiFi environments are located.

Nobody wants to spend money today on a standard that was ratified back in 2009. Fortunately, 802.11ac is much better than you think and provides a lower megabits-per-second cost than 802.11n. But don't take my word for it. Add a few 802.11ac APs and see if they're justified in your environment. I think you'll be surprised by what they can do.

Robert Fenstermacher is a product and solutions marketing director at Aruba Networks with primary responsibility for Aruba's Unified Access and Network Services strategy. 

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Susan Fogarty
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Susan Fogarty,
User Rank: Strategist
12/16/2013 | 8:31:21 AM
Re: Straight talk about ac
@rfenster, thanks so much for your response. So even if you replace APs one-for-one, in the long run you'd be installing many fewer APs overall. I'm also interested in finding out from the community what the WiFi demands are in their businesses, and how theri coping.

Robert, do you have any recommendations for how IT departments can estimate wireless growth so they aren't caught unawares?
rfenster
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rfenster,
User Rank: Apprentice
12/13/2013 | 7:19:12 PM
Re: Straight talk about ac
Susan, great question. Technically, you increase the overall capacity and have better rate at the same range with 802.11ac. So if you wanted to reduce the number of APs for the same performance as 802.11n it would be possible; but as you mentioned, most organizations see Wi-Fi traffic growing so quickly that reducing the number of APs isn't really realistic. There are other nuances with the new standard and with how a previous Wi-Fi network was designed that may affect the number of new APs and placement, but for the most part organizations will probably come close to a 1:1 swap.

I'm curious what others are seeing in terms of demand for Wi-Fi? How are you coping with more devices, bandwidth hungry apps, and over-the-air mobile app and OS updates?
Susan Fogarty
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Susan Fogarty,
User Rank: Strategist
12/13/2013 | 11:31:59 AM
Straight talk about ac
Robert, thanks for the low-down on 11ac. Will businesses actually be able to decrease the amount of APs they are using with the new standard? Or will that never be the case, because demand for Wi-fi is growing at such a rapid pace?
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