The 802.11ac Paradox
Lee H. Badman
May 28, 2013
With an expected Q4 ratification for the 802.11ac standard, the buzz for gigabit wireless is getting louder. And why not? The 11ac data rates run circles around even fast 11n networks. We've covered what to expect from vendors selling early 11ac gear and how customers can prepare themselves for the new standard.
And yet, the fact is the next generation of wireless will require a whole bunch of wires and a whole lot of hardware. The 802.11ac standard does amazing things with radio waves and spectrum, but none of it matters without the right physical cables and reams of new switch configurations.
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With 11n and earlier WLAN technology, a single cable run from a relatively simply configured switch port provided both power and data backhaul at either 100 Mbps or Gigabit. Depending on switches in use and grade of wire installed, the same switch/config/cabling combos have served many of us through at least a couple of wireless lifecycles.
However, 11ac is a radical change; if you go by emerging WLAN guidance on prepping for and implementing the latest wireless standard, your to-do lists get significantly complicated.
The short version: 11ac will require two switch ports and two cable runs per access point. Simple AP uplinks now become port channels. Port channels need careful configuration, and can be a nightmare to troubleshoot should one of the four RJ-45 connectors involved with each 11ac port channel get cocked or not sit straight in its port.
Let's say you're upgrading a 2,000 AP WLAN to 11ac, and you've determined you can do a simple "rip and replace" upgrade with no AP location changes. You have to calculate the price of new access points, licensing, and time spent on potential controller and management system upgrades. But you're also on the hook for:
- 2,000 more switch ports
- Maintenance contract costs on X additional switches
- Potential license costs for new switches in your management/monitoring system
- Some number of new UPS systems for switch adds, depending on backup time requirements
- Possible wholesale switch environment upgrade depending on PoE support
- At least 16,000 new config line commands (based on 8 commands per port channel/port config)
- 16,00 chances to screw something up in configuration or physical connectivity
- 2,000 new cable runs
- Potential pathway costs
- Possible asbestos/hazardous material abatement costs associated with new cable runs
- Recertification of existing AP cable plant, if necessary, with upgrades where needed
I don't expect a lot of vendors to include these items in their upbeat TCO calculators. Nor is my summary meant to cast aspersions on the fantastic beast that is 11ac. But for those of us who have to make it work, we need to live in reality. Even if your vendor of choice doesn't need all of this for Wave 1 11ac, it certainly will for Wave 2 unless the industry comes up with something truly innovative. And that may be too much to ask.
In my next post, I'll look at why much of the build-up to 11ac, and the related demands that WLAN vendors will put on customers, might just be wrong for all parties.