Tuesday, 20 January 2015

Revolution of 5 Generation Wi-Fi Standard (802.11ac)

802.11ac is the next generation for wireless networks and manufacturers are now deploying equipment with this new technology and marketing the heck out of it. Now the question is when should you look at deploying it and what do you benefit from these new wireless solutions ?

If you have recently deployed an 802.11n network I wouldn’t worry about it. You still have lots of life left in your investment and unlike previous generations of wireless networks this one is ok to mix in with your current 802.11n wireless network. That means you can buy an 11ac AP here and there over time and replace or supplement your existing wireless network with these new APs. There are lots of things to consider though when deciding how to deploy this new technology but for right now we are going to focus on what does AC offer versus N wireless.

There are the mostly four factor revolution to use the 802.11ac.
  • Speed
  • Rang 
  • Capacity 
  • Compatibility 


The first big gain we get with 802.11ac wireless is faster speeds. Faster speeds mean more bandwidth for everyone involved because the faster I can get you the data you requested the faster I can get to the next guy in line who is trying to get to his Vine video of the day. With 802.11ac the first generation of APs is going to provide up to 1.3Gbps of bandwidth. This is about 3x the bandwidth we can currently get from an 802.11n AP with dual radios today. The speeds of course are all dependent on optimal variables like, client device capability, distance from the AP, RF quality, etc… So suffice it to say that 802.11ac is like replacing your family sedan with a Ferrari!


The first point to make is the 802.11ac standard lives entirely in the 5GHz spectrum. While some more modern routers broadcast 802.11n in 5GHz as well as 2.4GHz they remain relatively rare.  

Consequently, the 5GHz spectrum tends to be 'quiet', meaning much less interference from neighbourhood Wi-Fi. This more than counters the fact that, in lab conditions, 5GHz signals do not actually broadcast as far as 2.4GHz signals. 5GHz is also necessary to support the faster speeds of wireless ac. 

The second key factor is 802.11ac makes ‘beamforming’ a core part of its spec. Rather than throw out wireless signal equally in all directions, WiFi with beamforming detects where devices are and intensifies the signal in their direction(s). 

This technology has been around in proprietary form (it made a huge impact in the D-Link DIR-645), but now it will be inside every 802.11ac router and every 802.11ac device. 

The combination of these two technologies is profound. This was most clearly seen with the Linksys EA6500 which hit speeds of 30.2MBps (241.6Mbit) when connecting to a device just two metres away, but still performed at 22.7MBps (181.6Mbit) when 13 metres away with two solid walls in the way. By contrast Linksys’ own EA4500 (identical except being limited to 802.11n) managed 10.6MBps (84.8Mbit) dropping to 2.31MBps (18.48Mbit) under the same conditions. 

The real world result is 802.11ac not only enables you to enjoy the fastest 100Mbit (and beyond) fibre optic broadband speeds all over the house, but to enjoy it along with multiple streams of Full HD content, super low latency gaming and blazing fast home networking all at the same time. 


The next big gain 802.11ac provides us is better client capacity. With 802.11n wireless we recommended no more than 30-40 clients to an AP for optimal performance. This isn’t because of limitations in the access point hardware but rather limitations based on bandwidth. RF is a shared medium and there isn’t an unlimited amount of airtime or bandwidth. Because wireless clients are sharing the bandwidth on an AP each is only going to get a slice of the total amount of bandwidth offered by it. For instance, a dual radio 802.11n AP that provides 450Mbps to 50 clients is going to net each client about 9Mbps in total bandwidth. When you factor in overhead, spectrum interference, etc… the actual total bandwidth to the client will be much less. If my client count is less on the AP each client will have more bandwidth allocated to them. 25 clients on the same 802.11n AP will net 18Mbps per client which is much better than 9Mbps. With 802.11ac we have a lot more bandwidth to distribute and better methods of doing it so the client count can be much higher on an 802.11ac access point than on 802.11n.


The first thing to get out of the way is - like past Wi-Fi standards - 802.11ac is backwards compatible with 802.11b, g and n. This means you can buy an 802.11ac-equipped device and it will work just fine with your existing router. Similarly you can upgrade to an 802.11ac router and it will work happily with all your existing devices. That said you will need both an 802.11ac router and an 802.11ac device to enjoy the standard’s biggest benefits. And those begin with…