This week was the annual announcement of the Apple iPhone refresh. There were a lot of interesting technologies discussed around the newest entry in the Cupertino Fruit and Mobile Company but one of the most exciting came in the form of the wireless chip. The original iPhone and the iPhone 3G were 802.11b/g devices only. Starting with the iPhone 3GS, Apple upgraded that chip to 802.11b/g/n. With the announcement of the new iPhone 5, Apple has finally provided an 802.11a/n radio as well, matching the 5GHz capability as the iPad. This means that all Apple devices can now support 5GHz wireless access points. Along with the latest Android devices that offer similar support, I think the time has come to make a radical, yet needed, design decision in our wireless networks.
It’s time to abandon 2.4GHz and concentrate on 5GHz.
Matthew Gast from Aerohive had a great blog post along these same lines. As Matthew explains, the 2.4GHz spectrum is awash with interference sources from every angle. Microwave ovens, cordless telephones, and wireless video cameras are only part of the problem. There are only three non-overlapping channels in 2.4GHz. That means you’ve got a 33% chance of interfering with surrounding devices. If you’ve got one of those fancy consumer devices that can do channel aggregation at 2.4GHz, the available channels decrease even further. Add in the fact that most people are carrying devices now that are capable of acting as access point, such as MiFi hotspots or the built-in hotspot features in tablets and smartphones and you can see how the 2.4GHz spectrum is a crowded place indeed. On the other hand, 5GHz has twenty three non-overlapping channels available. That’s more than enough to satisfy the more dense AP deployments required to provide similar coverage patterns while at the same time providing for high speed throughput with channel aggregation.
There are a number of devices that are 2.4GHz only and will continue to be that way. Low-power devices are one of the biggest categories, as Matthew pointed out. 2.4GHz radios just draw less power. Older legacy devices are also not going to be upgraded anytime soon. That means that we can’t just go around shutting off our 2.4GHz SSIDs and leaving all those devices out in the cold. What it does mean is that we need to start focusing on the future of wireless. I’m going to treat my 2.4GHz SSIDs just like a guest access VLAN. It’s there, but it’s not going to get much support. I’m going to enable band steering to push the 5GHz-capable clients to the better access method. For everyone else that can only get on at 2.4GHz, you get what you get. With more room to grow, I can enable wide channels and let my clients pull all the data they can stand from 5GHz. When the rest of the world gets ready to deploy 802.11ac devices and APs, I’ll already have experience designing for that band. My 2.4GHz network will live on much the same way my 802.11b clients lived on and my Novell clients persisted. They’ll keep churning until they are forced to move, either by failure or total obsolescence.
Yes, it’s a hard choice to make right this moment to say that I’m leaving 2.4GHz to the wolves and moving to 5GHz. It’s a lot like making the decision between ripping the band-aid off or pulling it slowly. Either way, there will be pain. The question becomes whether you want the pain all up front or spread out over time. By making a conscious decision to start focusing your efforts of 5GHz, you get the pain out of the way. Fighting for spectrum and positioning around kitchens and water pipes all fall away. Coverage takes care of itself. Neat new technology like 40MHz channels is simple, relatively speaking. Let the 2.4GHz clients have their network. I’m going to concentrate my efforts on where we’re headed, not where we’ve been.