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Lee Badman
Lee Badman
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802.11ac: Cisco, Aerohive Offer Forecasts

802.11ac promises significant improvements for WLANs. I interviewed representatives from Cisco Systems and Aerohive Networks to get their input on 11ac, how it will affect corporate networks, and if and when IT should upgrade.

With the 802.11ac standard expected to ratify in 2013, early product releases are heating up. With any new wireless technology comes confusion, so I went to a couple of heavy hitters in the industry to get their take on what we should all know about the coming of 11ac.

Chris Spain currently serves as VP of product marketing at Cisco Systems. Andrew vonNagy is a senior Wi-Fi architect with Aerohive Networks. I use and support gear from both companies. Though Spain and vonNagy come from different places on the WLAN vendor spectrum, both sing similar songs when it comes to 11ac. Each provided a slew of input on my questions, which I have condensed for brevity.

Q. What will 11ac mean on day one, and down the road, to the SMB and enterprise spaces?

Spain: There won't be a lot of 11ac clients in the beginning, and both clients and infrastructure are needed to fully leverage the anticipated benefits of 11ac. The new standard will be evolutionary, with two waves involved. Out of the gate, the increases in performance over 11n will not be tremendously impressive. The second wave--which will require a hardware refresh--gets far more interesting.

vonNagy: First-generation 802.11ac products will achieve up to 1.3 Gbps through the use of three spatial streams, 80-MHz-wide channels (double the largest 40 MHz channel width with 802.11n), and use of better hardware components that allow higher levels of modulation and encoding (up to 256-QAM). Whether we will actually see 802.11ac products capable of 6.9 Gbps is dependent on hardware enhancements on both the access point and client that are not certain.

Both Spain and vonNagy agree that among the biggest benefits of 11ac are that more mobile clients will move to the 5-GHz spectrum where 11ac lives, and that faster data transfers should mean longer client battery life.

Q. Should existing wireless environments be in a hurry to go to 11ac?

vonNagy: Enterprises that have deployed the latest-generation 802.11n equipment pervasively throughout their network can be confident in the investment they have made; first-generation 802.11ac only offers incremental benefits over 802.11n. First-generation 802.11ac products will be of greater interest to enterprises that are purchasing a greenfield WLAN deployment, growing an existing WLAN deployment with additional APs, or running older WLAN equipment. Enterprises that were early adopters of 802.11n may see greater appeal in moving to first-generation 802.11ac because their existing 802.11n equipment has already been depreciated over a number of years and they have received their return on investment. In addition, 802.11ac can offer a substantial upgrade in performance to 600 Mbps over two spatial stream 802.11n (300 Mbps), allowing the enterprise to increase performance, capacity and services offered over the WLAN.

Spain: It depends where in the lifecycle of your current WLAN you are. Fresh 11n deployments should be good for another three years or so until 11ac becomes compelling, but those still running a/b/g environments should perhaps consider 11ac over 11n. Also, if you have specific client types where increased battery life is of particular concern, this could be a driver for migration to 11ac. You also may have targeted areas in the WLAN where 11ac makes sense for a particular reason that doesn't necessarily dictate moving the entire enterprise to the new standard.

Q. Where do you see 11ac being over/under-hyped?

Spain: Speed sells, and 11ac is faster than 11n, so naturally we'll hear a lot about that. But just having a new wireless gigabit on-ramp isn't the end of the story. What's not being talked about enough is that 11ac clients will free up more 2.4-GHz space for clients that can't upgrade, and that advanced features like multiuser MIMO will provide wireless performance that is more switch-like compared to the shared media nature of 11n.

vonNagy: Most of the current discussion on 802.11ac focuses on large bandwidth improvements that will not be available for several years. The short-term improvements are of bigger benefit in small WLAN deployments, such as SMB and consumer homes, where only a single Wi-Fi AP will be able to take advantage of much wider channels.

One major short-term benefit of 802.11ac not being discussed as much as it deserves is the dramatic ability for enterprise WLANs to serve mobile devices in greater quantity with better performance. This is due to the mandatory support of 5-GHz frequency bands by all 802.11ac-compliant equipment. Today, enterprise WLANs struggle to provide the capacity required to support the influx of mobile devices. Once mobile device manufacturers begin deploying 802.11ac-capable devices, existing 802.11n and new 802.11ac WLAN deployments will be able to provide significantly better services to mobile devices.

Q: Beyond replacing access points, how will 11ac affect business environments?

vonNagy: Enterprises in multitenant buildings or in dense urban areas will likely see increased utilization of the 5-GHz spectrum bands, which could cause greater levels of interference and degrade WLAN performance. This is of significant concern if enterprises deploy 802.11ac equipment with 80-MHz wide channels, without recognizing the impact to neighboring businesses. 802.11ac also threatens to accelerate the utilization of 5-GHz spectrum bands by a large majority of enterprises. This could be a double-edged sword, providing the promise of increases performance for individual organizations, while simultaneously congesting the once interference-free 5-GHz bands. This may expose the need for more unlicensed spectrum sooner than anticipated. The timing is impeccable, as the FCC and Congress are currently devising rules for spectrum auctions in 2013 and 2014 of the 600-MHz TV white spaces and spectrum-sharing plans in the federal 3,550-to-3,650-MHz band. This would provide additional unlicensed spectrum for general use.

Spain: The notion of a faster on-ramp for wireless devices brings up interesting possibilities. At some point you have to talk about controllers and such, and how all parts of the network evolve, but 11ac has particularly interesting implications in the branch setting. Where you may not choose to use Flex Connect now [formerly called HREAP, Cisco's wireless system for branch and remote offices], having wireless clients pushing gigabit speeds at the far end changes how you think about the merits of backhauling all client traffic to your central site.

Thanks to Spain and vonNagy for participating. As 11ac continues to creep up on us, I'll speak with other industry leaders and sharing their thoughts here.

Lee is a Network Engineer and Wireless Technical Lead for a large private university. He also teaches classes on networking, wireless network administrtaion, and wireless security. Lee's technical background includes 10 years in the US Air Force as an Electronc Warfare ... View Full Bio
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