802.11n vs. 802.11ac: Which Wireless Will Work for You?
Remember when a strong Wi-Fi signal was a luxury? That era is long gone. Today, wireless networks are core productivity tools. Like all technologies, wireless continues to evolve. Earlier Wi-Fi standards, including 802.11n, still serve the needs of companies far and wide. But the recent ratification of 802.11ac gives enterprises some powerful new features.
802.11n vs. 802.11ac: A snapshot of the standards
Building on earlier standards, 802.11n was the first to boast single-user multiple-input multiple-output (MIMO) antennas. It supported up to 600 Mb per second (depending on the client—450 Mb per second was about average) and enterprises can go up to a channel width of 40 MHz with their 802.11n gear.
The 802.11ac standard will arrive in two waves, the first of which is already here. Among the primary advancements in wave 1 was a speed of 1.3 Gb per second, though John Anderson, product planner for the carrier business unit at Fluke Networks, said user throughput "will never be that high." He estimated a real-world number of about 60 percent of that, saying "the actual user data rate depends on a lot of factors, one of them being how many people are on the network, and others being environmental—how far from the AP you are, how much noise there is, how much interference there is." That theoretical 1.3 Gbps speed has since been exceeded by the 802.11ac -2013 update, formally approved by the IEEE in early 2014. 802.11ac -2013 allows for a whopping 7 Gbps of data in the 5 GHz spectrum.
In addition, with 802.11ac, channel width doubles to 80 MHz, and beamforming is standardized for better interoperability. Christian Gilby, director of product and solutions marketing at Aruba Networks, said wave 1 also brings with it the more efficient 256-QAM (quadrature amplitude modulation). "Basically, it gives you about 33 percent more throughput at the same location from an access point," he explained.
Many enterprises are hankering for the second wave of 802.11ac, which Gilby said will probably start Wi-Fi Alliance certification in late 2015. Perhaps most significant is the anticipated release of multi-user MIMO for the downstream direction, an improvement that will give a switch-like experience to APs with transmission to multiple clients simultaneously. "I could send two spatial streams to one client, one spatial stream to another," Gilby explained. Wave 2 of the standard is also expected to bump from 3 spatial streams to 4, giving another 33 percent speed improvement.
Gilby said there is a small downside to multi-user MIMO, in that connecting clients will need wave 2 chipsets, "otherwise they have to fall back to wave 1 operation." He anticipates a lag of around a year before there is sufficient momentum on the client side to really take advantage of the multi-user MIMO functionality. In addition, he believes another advancement planned for wave 2—a move to 160 MHz channels—probably won’t translate fully into reality.
"Honestly, you won’t see that in the enterprise," Gilby said. "Because it’s only one and, if you count DFS, two channels available. You just can’t do a channel plan for deployment with one or two channels." As a result, he expects to see it leveraged primarily in the home.
Equipment is expensive, and one standard may suit an enterprise’s needs better than another. A couple of real-world deployments offer a look into how the standards are performing in the wild and where each is excelling.
Case study: The house bets on 802.11n
People don’t think of a casino as a typical enterprise, but in fact it’s a perfect example of a complex and very diverse environment. Dhritiman Dasgupta, senior director of product marketing at Juniper Networks, said the team helped a customer deploy an 802.11n wireless solution in just such an enterprise last year.
Dasgupta said there are essentially three use cases with discrete requirements in a typical casino-hotel. The first is the mission-critical casino floor, with its slot machines and money carts accessing the wireless network for information transfer and location tracking. "Then there are bars and restaurants, where people are taking orders for drinks or food, and those devices are also on the same wireless network," Dasgupta explained.
Next are the guest rooms. Wireless access for guests is just one of many considerations when deploying a Wi-Fi network in a modern-day hotel. "You’ve got the mini-bar, the HVAC system, the lights, the curtains. Everything is connected to that same network," Dasgupta said. The number of machines communicating through Wi-Fi will likely only grow as guests increasingly bring multiple devices and the sensors necessary for more efficient building automation continue to be added.
Finally, most casino-hotels also boast a number of large conference rooms capable of holding several thousand people. Each event lasts a few hours, during which time Dasgupta described network activity as "pandemonium." Attendees are exchanging e-mails and updating their social media feeds. "There might be an application on somebody’s phone to guide them to where the restroom is, where the elevators are," Dasgupta said. It becomes a very high-density environment in short order.
In reviewing its requirements across these three use case scenarios, Dasgupta’s casino client determined 802.11n technology would serve them well for now, though they’ll likely want to upgrade to 802.11ac at some point. "The good thing about these standards is that you could start with 802.11n, which is what we deployed, but the controllers and the management system are 802.11ac-enabled," Dasgupta explained.
The conference rooms and banquet halls will probably be the first to migrate to 802.11ac. "That’s because of the density and the coverage needed, and 802.11ac allows much higher levels of performance," Dasgupta said. When that time comes, the equipment’s built-in compatibility means the client will be able to focus their attention on upgrading access points without a lot of other forklift worries.
Case study: A prescription for 802.11ac
John Anderson, product planner for the carrier business unit at Fluke Networks, said he began seeing some of the first 802.11ac deployments shortly after the standard’s ratification in the last quarter of 2013, and they’ve been picking up since then. "Where we’re really seeing them is in places that have a lot of users using high-speed applications," he explained. One industry that typifies that environment is healthcare.
A challenge in many hospital deployments is that a multitude of device generations must be supported. Fluke Networks recently worked with several hospital organizations to upgrade their Wi-Fi systems to 802.11ac, and Anderson said they consistently found many devices running legacy technology. The backwards compatibility of 802.11ac—and the ability to support both the 2.4 GHz as well as the 5 GHz bands—is crucial to incorporating these diverse users.
"They can deploy 802.11ac access points and still support all of these legacy technologies like 802.11b. It’s a requirement for many customers, including some of the hospitals that we see 802.11ac going into," Anderson explained.
Multi-user MIMO will be a big move forward for healthcare organizations. "That’s going to significantly increase the number of users that can be on a network," Anderson said. That’s good news in enterprises where in-house providers are frequently joined by consulting physicians and others who rely on solid Wi-Fi coverage for fast network access. The physical data rate of 802.11ac is another crucial deciding point in healthcare, as data-intensive applications increasingly rule the airwaves.
802.11ac in the enterprise: Benefits and challenges
The speed, capacity, and performance improvements 802.11ac offers over 802.11n promise several compelling benefits to the enterprise. 802.11ac is well-suited to handling streaming video, making it ideal for enterprises becoming increasingly reliant on video conferencing and collaboration and for enterprises that need to preserve service for streaming media and data-intensive applications. Additionally, as BYOD continues to grow its foothold in the enterprise, 802.11ac will help support the larger numbers of devices connecting to corporate WLANs. Recent releases of consumer mobile devices, such as those running iOS and Android operating systems, offer 802.11ac compatibility to maximize performance.
These benefits do create additional network management challenges, however. 802.11ac and BYOD may lead to a sharp increase in wireless traffic on enterprise networks, and traditional data capture and traffic analysis and troubleshooting tools might not be able to keep up. Organizations may need to invest in new tools to handle 802.11ac network management and troubleshooting. When all is said and done, however, enterprises with significant wireless networking needs should find their investments rewarded by better performance and quality of service.
802.11ac backwards compatibility and a look ahead
While 802.11n networks may one day transition to the new 802.11ac standard, a significant number of enterprises are actually still on one of the earlier 802.11a/b/g flavors of wireless. These companies are likely experiencing problems and bottlenecks with their current wireless network infrastructure, and will "probably skip 802.11n completely and just go to the first wave of 802.11ac," Dasgupta said.
For enterprises working to move from the 802.11n standard up to 802.11ac, Dasgupta said, "There is good compatibility for somebody who starts with 802.11n, goes to the first wave of 802.11ac and then moves to the second wave." In fact, he said his team is hearing from a number of customers who simply plan to wait for the second wave of 802.11ac before transitioning. Because the equipment is designed to be backwards compatible, he said, "Even with the investments they make in their controllers and their management solutions today, that carries them all the way through to the second wave."
Though 802.11n remains the dominant Wi-Fi standard to date, there are signs that 802.11ac is building steam, driven in part by lower prices for 802.11ac equipment, according to the Dell'Oro Group. Is your organization planning to upgrade to 802.11ac? Tell us your thoughts in the comments.