Deploying Wi-Fi CERTIFIED™ ac: Exploring the options

With products based on the 802.11ac standard now appearing in great numbers in the marketplace, the debate over when to deploy this exciting advance in Wi-Fi® capabilities is also well underway. Note that I say when here – it’s not a question of if, but rather how to schedule 802.11ac rollouts.

There are many considerations here, of course, including all of the usual suspects: cost, traveling up the learning and experience curves, and, of course, finding the right product. But let’s get a couple of issues out of the way up front. 802.11ac is now an approved IEEE standard. Wi-Fi Alliance® has its Wi-Fi CERTIFIED™ ac certification program. The cost of 802.11ac-based products is the same as or only slightly higher than 802.11n products from a given vendor. And, 802.11ac opens up new possibilities for throughput, capacity, improved rate-vs.-range performance and price/performance, as well as exploiting the underused 5 GHz bands.

And yet there are still some who want to wait before taking advantage of 802.11ac. But, to be fair, let’s look at the pros and cons of the major deployment options in detail, as follows:

• Deploy an 802.11ac overlay now – This will likely be the most common option, as IT shops begin to augment their current plan with 802.11ac products. These will often be deployed in areas with concentrations of power users, and certainly in any greenfield situation. Some shops will operate these entirely in backwards-compatible 802.11n mode for a period of time, with cutover to 802.11ac as client bases build.
• Rip-and-replace the current infrastructure – While less common than the overlay, an argument can be made for “rip and replace” when the existing APs will be redeployed to locations with less demand, when pulling new Ethernet cables (Farpoint Group recommends two of these to any 802.11ac AP), or when deploying more PoE (Power over Ethernet) switch ports can’t be managed at present.
• Deploy for assurance purposes only – Assurance functions include such necessities as spectral analysis, IDS/IPS, and rogue detection. While these are often provisioned by a separate assurance system with its own sensors, many APs can also be configured as sensors, and re-purposed later, if so desired, for access. Regardless, 802.11ac assurance functionality is essential, and shops not currently monitoring the 5 GHz bands need to do so right away.
• Wait for Wave 2 – The next generation of 802.11ac, informally known as Wave 2, includes channels wider than 80 MHz, more than three MIMO streams (Farpoint Group expects peak throughput in the range of 1.8-3.5 Gbps), and a new feature known as multi-user MIMO (MU-MIMO), which allows multiple client devices to receive independent data streams during a single AP transmit cycle. MU-MIMO may result in higher overall system capacity, especially given that most clients, we expect, will be single-stream (typically 433 Mbps) implementations that otherwise waste the 867-1300 peak Mbps of current 802.11ac APs.
• Ignore the issue altogether – Given how new 802.11ac is, and the fact that 802.11ac clients are not exactly plentiful today, many assume there’s no immediate need for .11ac in most shops - 802.11n has been getting the job done for some time, and postponing, perhaps indefinitely, 802.11ac has no apparent downside.

I think it’s pretty clear from the above arguments that waiting to deploy 802.11ac makes very little sense. IT shops that do nothing are likely to see an exacerbation of the WLAN capacity constraints building everywhere today, these resulting from increasing numbers of wireless users with similarly-increasing numbers of fundamentally- and essentially-wireless devices, and who expect wireless access to every application without exception. Sure, existing infrastructure can be augmented with more 802.11n (and hopefully not with any WLAN technology older than that!), but 802.11n is clearly at the end of its innovative life. While we expect up to five more years of ROI from 802.11n, the improved 802.11n client performance we’re already seeing (on the order of 15-20%) in 802.11ac APs operating in 802.11n mode and the fact that 802.11ac APs cost little (if any) more than their 802.11n counterparts means that price/performance is improved as well. And keep in mind that the number of client devices equipped with 802.11ac will see a big uptick this year – we expect that by the end of CY14, over half of all WLAN-equipped client devices shipping will have at least a single-stream 802.11ac radio built in.

Waiting for Wave 2 has a similar outcome. It’s always been true that the next high-tech product is always better than whatever came before, but waiting here means that one can’t take advantage of the productivity enhancements and other features of any given generation or implementation. Since IT overall is about improving the productivity of users (who, again after all, are way more expensive than the networks that they depend upon), waiting once again makes no sense. Realizing the full benefit of a Wave 2 network will also require new client devices, and can regardless be phased in non-disruptively over time.

So, then – the time for 802.11ac is indeed now. Waiting has no upside, and the overlay and/or assurance deployment models outlined above are simple, cost-effective techniques for easing into what is clearly the future of enterprise and organizational wireless LANs.