• United States
by Jay Botelho, Director of Product Management, WildPackets

Top things to consider as you prepare for the transition to 802.11ac Gigabit Wi-Fi

Aug 28, 20146 mins

wifi gigabit
Credit: Shutterstock

This vendor-written tech primer has been edited by Network World to eliminate product promotion, but readers should note it will likely favor the submitter’s approach.

The move to 802.11ac gigabit Wi-Fi is picking up steam, seeing a 540% increase since 2013, for obvious reasons: 802.11ac is faster, more agile and more robust than any of its predecessors. Providing Wi-Fi at the speed of wired networks, 802.11ac is revolutionizing how enterprises support the large quantity of devices connecting to their corporate networks. With multiple product introduction waves expected in the coming years, adoption will only accelerate.

With all that 802.11ac has to offer, organizations need to make sure they are set up for success. Here are the top things to consider as you prepare for the transition:

* Consider your options. The basic consideration is this: rip-and-replace, or simply add a new 802.11ac network to your existing WLAN (often called an “overlay” network). If your network is like most enterprise networks, the bulk of your traffic is probably still in the 2.4GHz band, using the traditional b/g channels. Even if you’ve added 802.11n along the way, it’s most probably still heavily focused in the 2.4GHz band.

If this is the case, an overlay network is the way to go. Since 802.11ac only uses the 5GHz band, there will be little or no disruption to your current user base, and new clients with 802.11ac technology will immediately benefit from the new network. And, if you have clients that already support 802.11ac technologies (like the newer Macbooks) you will even see a benefit on your existing 2.4GHz network as these users will seamlessly migrate to the new 802.11ac network, freeing up bandwidth on the 2.4GHz channels.

ABI Research predicts that 70% of smartphone shipped by 2015 will have “ac” chipsets, and since smart phones are probably the biggest BYOD challenge, moving them off to a new 802.11ac network in a new frequency band will provide some instant relief.

However, 70% isn’t everyone, and there are still all those 802.11b/g/n laptops to worry about. An overlay strategy will allow these devices to remain viable until you’re ready to replace them, and if you have certain users who must have the performance of 802.11ac, they can always do an inexpensive “upgrade” by simply buying an 802.11ac WLAN USB adapter.

Rip-and-replace is a complete replacement of all 802.11 APs (and probably all controllers if your WLAN is controller-based). Since most 802.11ac APs are dual radio, with one of the radios supporting the legacy 2.4GHz band (b/g/n technologies), you won’t lose support for existing clients, and you’ll end up with a simpler and easier to manage WLAN infrastructure. But a rip-and-replace strategy is typically more expensive, as you’ll need new APs everywhere, not just in the areas where you need higher capacity today.

The overlay vs. rip-and-replace decision is not an easy one, and it includes factors beyond just technology. It’s important to analyze the financial impact and determine which solution is best for you. But if you haven’t yet made a big investment in 802.11n, and you know you’re WLAN needs a serious overhaul, a complete rip-and-replace may be the best strategy.

* Survey your site. Site surveys are always controversial. Some swear by them. Others see the time and consulting fees as a waste. But regardless of whether you plan to just add some 802.11ac equipment, or do a wholesale replacement, now is the time for a site survey. With 802.11ac you’re entering some unchartered territory: the 5GHz band. A professional site survey will tell you exactly what the 5GHz band looks like in your environment, helping you identify and avoid existing interferers, and make smart configuration choices for your new equipment.

With all of the new features in 802.11ac, including some optional advanced features like beam-forming, the only effective way to truly take advantage of 802.11ac is to use a site survey to come up with a sensible WLAN design. You will converge on a design much more quickly, with the time savings more than paying for the cost of the survey.

* Wired upgrades? The migration to 802.11ac means speed. And that presents some new challenges in deployment and management. Gone are the days when a 100Mbps link to your access points was sufficient. With 802.11ac, maximum data rates easily exceed 1Gbps with current phase 1 technology (1.3Gbps to be exact), and will be creeping up towards 2Gbps with phase 2 equipment.

Even though the aggregate data rate from these APs will never hit these maximums, aggregate data rates in the range of 500M – 800Mbps will be possible on networks with primarily 802.11ac clients. This means you need at least a 1Gbps drop to each AP, and you may need to plan for more if you expect to continue to upgrade your 802.11ac equipment to take full advantage of what it will offer over time.

* Don’t drop your packets. In the good old days network monitoring and analysis was pretty straightforward. Access points (APs) and the USB WLAN adapters typically used to capture packets for monitoring and analysis pretty much had the same capabilities regarding encoding, data transmission, and data rates. But with 802.11ac, APs often have much greater capabilities than clients, and this is especially true when comparing 802.11ac APs with 802.11ac USB WLAN adapters.

As a result, attempting to monitor and troubleshoot an 802.11ac network with an 802.11ac WLAN USB adapter can be very problematic. The WLAN adapter will not capture, and will not even indicate in any way, that there is 802.11ac traffic that exceeds its data rate capabilities. This results in serious blind spots in network analysis and troubleshooting.

The exponential growth of mobile access and its introduction into the workplace has accelerated the need for network reliability and uptime. The new 802.11ac wireless standard offers increased throughput, better capabilities for multiple users, and overall improved features for the content- and data-heavy networks of today. 802.11ac improves the WLAN user experience by providing data rates more 10 times the speed that was previously available.