Sep 03 2013

Wireless, the Next Generation: 802.11ac

Gigabit Wi-Fi promises extraordinary improvements in speed, reliability and quality.

Over the last decade, wireless networking has evolved from a new and somewhat unproven technology to a critical component in the enterprise IT arsenal. Today, virtually every organization operates a Wi-Fi network for internal or public use.

“It has become the primary way to access the Internet and network data,” observes Zeus Kerravala, principal analyst at ZK Research in Westminster, Mass. “It has moved beyond hot spots to the point of becoming pervasive.”

The need to access network resources is heavily driven by the widespread use of mobile devices, including notebooks, smartphones and tablets. In many cases, staff, independent contractors and business partners carry multiple devices and require instant access to the enterprise network, and the Internet.

“BYOD and the consumerization of IT have changed the dynamics of business in a significant way. Organizations must provide access with no trade-off in performance, convenience or security risk. It’s the baseline for business in the digital age,” Kerravala says.

As a result, a growing number of organizations are eyeing — and in some cases deploying — 802.11ac networking. The standard — soon to be ratified by IEEE offers greater bandwidth, much faster throughput speeds and a number of other features that make it ideal for today’s organizations.

Sizing-up 802.11ac

The successor to 802.11n, named 802.11ac, is far enough along the way to standardization that vendors have the assurance to start releasing product. The 802.11ac standard is said to enable dramatic increases in wireless speed, reliability and quality.

So how should an organization approach 802.11 ac? What timetable should it set for deployment? And what practical and technical considerations should IT executives consider when rolling out the technology?

Although there’s no single template for approaching the wireless standard, entities should recognize that it’s not so much a question of if an organization should move forward with 802.11ac but rather when.

“The technology will move rapidly into the mainstream over the next few years,” notes Robert Wardin, a solution architect for CDW.

What’s more, it is backward compatible with previous generations of wireless technology operating in the 5GHz spectrum including 802.11a and 802.11n.

“It represents an attractive upgrade for many organizations,” says Wardin.

Embracing a Wireless World

When wireless networking technology took root in the late 1990s, it introduced a revolutionary concept: the ability to connect online without plugging in cables and wires. Most early networks were constructed in an isolated and ad hoc way, Kerravala points out. Since then, various generations of wireless technology, commonly referred to as Wi-Fi, have rippled through the enterprise and into the mainstream of society — adding speed, security protections and better connectivity.

Of course, many organizations currently rely on 802.11n, which offers two spectrum bands: 2.4GHz and 5GHz — and does a good job of providing bandwidth and speed, particularly at the higher band. The standard, introduced in 2009, also introduced multiple-input multiple-output antennas (MIMO) while offering maximum throughput to 450Mbps (with three spatial streams running at 150Mbps over 40MHz channels).

Wardin says that about 80 percent of the organizations he encounters use 802.11n. A few use 802.11a or 802.11b/g standards because they rely on legacy devices — often medical equipment — that operate only in workgroup bridge mode or do not require any additional throughput speed. In addition, some legacy endpoint devices don’t support WPA or WPA2 encryption.

But many organizations are moving forward with plans to migrate to 802.11ac, Kerravala says.

“As networks become more saturated or ‘densified’ with devices, a lot of IT shops are finding that there simply isn’t enough bandwidth for everyone and everything,” he adds.

In fact, once an 802.11n access point hits 65 or more devices using it simultaneously, performance and speed drop off considerably. In addition, the bring-your-own-device (BYOD) approach to mobility has created a more unpredictable environment. “It’s more difficult to anticipate usage patterns. There is less predictable data flow,” he explains.

The end result? A few large corporations as well as educational institutions and stadiums have become early adopters of 802.11ac, Wardin says. 802.11ac is also a boon for organizations involved in data intensive fields such as financial trading, hospitals using medical imagery and customer support centers, he adds.

Many of these organizations rely on ultrafast speeds and use multiple technology channels — including audio, video and telepresence — to communicate internally or with partners and customers.

Why Wireless Speed Matters

What’s appealing about 802.11ac is that it operates at about triple the speed of today’s Wi-Fi, or approximately 1.3Gbps.

In practical terms, this translates into an access point supporting a greater number of clients — and providing much better performance for those that rely on video and other high bandwidth applications. In many cases, depending on the distance of the device from the access point, speed and performance rival or exceed Gigabit Ethernet. (IT decision-makers may want to consider upgrading edge switch uplinks to support the increased capacity.)

“As networks become more saturated or ‘densified’ with devices, a lot of IT shops are finding that there simply isn’t enough bandwidth for everyone and everything,” says Zeus Kerravala.

Final ratification of the 802.11ac standard is expected later in 2013. However, industry experts don’t expect any significant changes — and any minor changes will be addressed through firmware updates. It’s also important to note that 802.11ac will come in two waves. The first release will include all basic features while a more advanced refresh — expected within three to five years — will likely introduce far more advanced capabilities, including channel bonding up to 160MHz, four spatial streams and multi-user MIMO.

The latter allows multiple network users to communicate with an access point simultaneously at a theoretical throughput of 68 gigabits per client conversation. Essentially, an AP with multiple antennas behaves more like a wireless switch.

Philip Solis, a research director at market intelligence firm ABI Research, says that 802.11ac is different from past protocols in that it must use 5GHz spectrum.

“If an 802.11n access point has single-band 802.11n relying on 2.4GHz, it would be backward compatible with the protocols on that same spectrum: 802.11b and 802.11g. If it has dual-band 802.11n (2.4GHz and 5GHz), then it would be backward compatible with 11b, 11g, and 11a,” Solis says.

“But 802.11ac only works in 5GHz, so it is only backward compatible with 802.11a and 802.11n. Fortunately, all access points and most devices will be dual-band 802.11n/ac. That would be backward compatible with everything,” he adds.

The 5GHz band, he says, creates more spectrum and, in turn, greater flexibility and real-world speed. He believes the standard will take shape in a major way this year.

“You can use larger channels and still have room for other nearby access points to use a different part of the 5GHz spectrum.”

The 5GHz spectrum has 23 non-overlapping channels compared to 2.4GHz which is limited to three non-overlapping channels. This helps minimize congestion and improves performance with less contention between devices.

Solis points out that a number of smartphone manufacturers, including Samsung and HTC, are now introducing phones that use 802.11ac. Wardin says that when Apple introduces the 802.11ac chips in its iPhones and iPads, adoption will spike. “There will be a huge reaction among corporate IT departments as well as educational institutions and government.”

802.11ac Strategy and Implementation

Developing a strategy and implementing a plan for 802.11ac is essential. The first step, Kerravala says, is to conduct an extensive site survey and include a spectrum analysis.

It’s crucial to understand how, where and the types of devices people are using on wireless connections — and how the situation might change over the next few years.

“Congested areas might include conference rooms, meeting areas or lobbies,” he explains. “Right now, if a bunch of people sit down at the same time and switch on their devices for a meeting, the experience can quickly deteriorate.”

But it’s also important to understand how people access data and interact in order to place APs in the right spots. For example, a virtual conference room that relies on video or other multimedia capabilities is likely to consume significant bandwidth.

“Some organizations record every meeting and they have cameras in conference rooms. This type of environment is likely to require additional bandwidth and some adjustments to the wireless infrastructure,” Kerravala notes. “It’s not as simple as swapping out 802.11n access points for an 802.11ac access points. The coverage patterns and interference patterns are different.”