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Now that the 802.11ac wireless LAN standard is all the rage in networking, organizations must consider their individual needs, including those of mobile end users, to determine if they should upgrade.
When the bombardment of 802.11ac announcements began well over a year ago, one number jumped out: 1.3 Gbps. There's no surprise that both chip vendors and system suppliers would lead with that high throughput number; after all, the history of wireless LANs has practically been defined by ever-increasing throughput.
Few people today remember that the original 802.11 standard from 1997 specified only one and two megabits per second. So organizations should be jumping for joy that 1.3 Gbps is so common and at such a low price.
And yet, do we really need that 1.3 Gbps? Even more to the point: Should 802.11n access points (APs) that are not yet fully depreciated be ripped out to hook up a bunch of shiny, new 802.11ac models to get that kind of throughput? And would enterprise mobile devices benefit from that upgrade?
Existing 802.11n offerings will continue to provide all the throughput and consequential end-user productivity that IT shops need for at least another three to five years. Still, organizations really should have 802.11ac wireless LAN in their planning, for a couple of reasons.
First, 1.3 Gbps represents the maximum physical throughput of the network under ideal conditions. It's best to plan on roughly half of that throughput being available to service required application performance. So even if IT plans on 1.3 Gbps, it can expect less than that. Adopting 802.11ac wireless LAN can help ensure that the network gets as much of a boost as possible, which in turn avoids disappointment among mobile users and the lost productivity resulting from a slow network.
It's also important to consider that demand on a per-user basis continues to increase, driven by both more mobile devices per user, as well as essentially every application going wireless, including streaming video and voice telephony. For those reasons, the most throughput you can get is always better.
Pros and cons of 802.11ac
One of the biggest challenges in networking is the distance at which a network can be effective, and 802.11ac addresses this via beamforming, which concentrates transmitted energy in a particular direction. Some .11n APs also have this capability, but .11ac makes it standard. This means that the rate of how well the wireless LAN performs versus the range over which the network works is improved.
Wave 2 of .11ac adds support for even larger channels (up to 160 MHz), four and maybe eventually even more multiple input, multiple output (MIMO) streams for greater network speeds -- as opposed to three that's common today. Plus, multi-user MIMO (MU-MIMO) enables multiple clients to receive unique data streams during a single AP transmit cycle.
But even with all these new capabilities, IT will still need to support an install base of .11n clients that will continue for many years to come. That's because what's really required isn't necessarily more throughput, but rather more capacity -- the ability to handle that large, growing and a more demanding user and application base. Higher throughput can help IT support more simultaneous users and apps, but admins can also obtain better performance by simply augmenting an .11n infrastructure already in place.
For example, 1.3 Gbps requires an 80 MHz channel, but you can get close to that level of throughput with two .11n APs, each on a 40 MHz channel. And more APs means those APs are deployed more densely, minimizing transmission distances and thus improving reliability -- and throughput. End users are unlikely to complain about a lack of capacity in this scenario.
There's really no rush to upgrade to .11ac if .11n continues to meet local user demands and traffic mix. But over time, most organizations will need to upgrade -- especially those with a lot of mobile users. Development for .11n is over, and .11ac represents the technology path going forward, at least until the next 802.11 standard is ready.
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