What do Network Admins Really Need to Know About 802.11ac Wireless?

By: Dustin Baker, Senior Systems Engineer at Trusted Network Solutions

Wireless history, if 802.11a was a two lane back road, 802.11b/g was a two-lane highway, 802.11n was a freeway, then 802.11ac is the Autobahn. 802.11ac has the ability to offer 1.3 gigabit per second wireless data speeds and potentially take away the need for wired workstation networks. This is exciting news for the technology industry, but we need look a little deeper before removing all of our network cable.

If we look at 802.11a, it has one 20 MHz channel and has between 20 to 25 available broadcast channels. This allows for many network signals to be broadcast close together and not have much co-channel interference. When I mention co-channel interference, I am talking about access points broadcasting the same channel and bumping into each other causing the access point to search for a new channel to broadcast on. With 802.11b/g, 40 MHz channels were created. This was done by bonding two 20MHz channels together as one channel. The combination of two 20 MHz channels allowed 802.11b/g to have 8 to 12 broadcast channels. This still offered enough broadcast channels for most environments that access points were not forced to change because of co-channel interference.

Along came 802.11n, this opened the door for 80 MHz channels “ four bonded 20 MHz channels” but only offered 4 to 5 broadcast channels. With the reduction in broadcast channels, we now truly started to see issues with co-channel interference. As 802.11n and access points have evolved, the industry has built in a couple of options to help with co-channel interference “power management and band steering”. With 802.11ac, this becomes a much bigger problem. 802.11ac offers 1 to 2 160 MHz channels “eight 20 MHz bonded channels”. In the United States, regulatory issues restrict wireless broadcasting channels to one channel at 160 MHz or 802.11ac. There have been rumors that the United States government is going to look at expanding the channel options for 802.11ac, but do not hold your breath for this one. In order to expand channel options, the United States government would need to allow co-channel interference with specified weather and air traffic control broadcast channels.

With 802.11ac, many vendors are saying it will deliver gigabit speeds to the wireless client, reduce network cabling, and be backward compatible. In reality, 802.11ac will not deliver gigabit speeds, because most network environments are not a test lab environment with the optimal configurations, it is your corporate environment. The corporate environment still has many interfering factors that will cause the wireless speeds to drop from the proposed optimal speed of 1.3 gigabit per second.

With cabling, you might not need to run as many cables to your workstations, but you will need to run two-gigabit cables to each access point. With 802.11ac, it requires two-gigabit Ethernet connections to the switch backbone.

Yes, 802.11ac is backward compatible, but only with 802.11n. That being the case, if your client environment is only capable of working with 802.11n and you have a fully deployed 802.11ac wireless network, your clients will only utilize the 802.11n “80 MHz” connection speed. If you have 802.11a and 802.11b/g clients, they will not be able to connect to an 802.11ac broadcasting environment. This is because the 802.11ac is only broadcasting in the 5GHz range. You would need a dual channel Access Point that also broadcasts on the 2.4GHz range to support the older wireless environment.

So the truth being told, yes 802.11ac will offer quicker speeds, yes in the perfect environment it will allow you to remove wired connections from your workstations, no is it not completely backward compatible, and it does cause potential major issues with co-channel interference. Is 802.11ac going to change how we look and work with wireless going forward? Yes. With the correct configuration of 802.11ac, an organization can become much more mobile in its design and much more secure.

For more information about being more secure with a wireless connection, please stay tuned for future blogs.

Author: Dustin Baker

About Trusted Network Solutions:

TNS is a leading Value Added Reseller providing secure network systems and solutions to the SMB and enterprise markets. TNS offers best-of-breed technical solutions acquired, installed, secured, and maintained using the most cost effective methods available.www.trustednetworksolutions.com


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