Wireless Standards – CompTIA A+ 220-901 – 2.5

| December 15, 2015

Our 802.11 networks are now the universal standard for connecting our devices without wires. In this video, you’ll learn about the evolution of our wireless standards and the specifications of our modern wireless networks.

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-You always hear wireless networks referred to as 802.11 networks. That number comes from the Institute of Electrical and Electronics Engineers, or the IEEE. And it’s associated with the IEEE Standards Committee 802. And they created the 802.11 to determine what standards should be used for wireless networking.

There have been many updates to wireless networks over time. In this video, we’re going to focus on the major releases of 802.11 networks, which are 802.11a, b, g, n, and ac.

802.11a operates in the 5 GHz frequency ranges. And it has a maximum theoretical throughput of 54 megabits per second The distance that you can communicate with 802.11a is a little bit smaller than what you would find in the 802.11b standard. That’s because the 5 GHz frequency range tends to be absorbed by other objects instead of bouncing off of them like it does in the 2.4 GHz range used with 802.11b. You’ll see that many people calculate the range of 802.11a as being about a third of the range that you would see with the 802.11b or 802.11g, which are running at 2.4 GHz.

We don’t generally see 802.11a being used any longer. When it was in use, it was generally in niche environments, which were very open. Things like warehouses, or large areas where you needed to cover a lot of distance and with a relatively high speed wireless network.

Released at the same time as 802.11a was 802.11b standard. This also came out in October of 1999. But instead of running at 5 GHz, it ran in the 2.4 GHz range. The maximum theoretical throughput of 802.11b is 11 megabits per second, which was much lower than 802.11a, which was 54 megabits per second

But this had a better range than 802.11a. There were less absorb shouldn’t problems when you had frequencies that were at 2.4 GHz. But unfortunately, there were a lot of other devices using 2.4 GHz that were in our homes. Things like, baby monitors, and cordless phones, and Bluetooth devices.

In June of 2003 we got an update to the 802.11a standard with 802.11g. Just like to b standard, the g standard is operating in the 2.4 GHz range. But the speed was increased to 54 megabits per second, matching what we found with 802.11a. Because this is an update to the b standard, it’s backwards compatible with devices that could use a two 802.11b. But of course, because it was running in the 2.4 GHz range, we still have the problem with interference with the other devices that we might have in our homes.

802.11n 11 was a release in October 2009 that effectively updated everything before it. This version operated at both 5 GHz and/or 2.4 GHz, depending on what hardware you would purchase. This also increased the speeds up to 600 megabits per second, which were obviously a significant increase over the previous versions. 802.11n was able to get the speeds using something called MIMO. This is multiple input, multiple output. And it could use for separate streams– each stream running at 150 megabits per second to get the total theoretical throughput of 600 megabits per second.

802.11ac was introduced in January of 2014, and it brought a number of improvements over 802.11n. This version operates exclusively in the 5 GHz band, and it has increased the number of channels that could be bonded together, and therefore increased the amount of theoretical throughput that we could have on these wireless networks. We’re also able to have faster data transfers. And when you combine the eight MIMO streams with these updates for the standard, we can have nearly 7 gigabits per second of throughput on an 802.11ac AC network.

Here’s a summary of these wireless standards. There’s the 802.11a, running at 5 GHz with a maximum theoretical throughput of 54 megabits per second You’ve got the 802.11b, which is a 2.4 GHz version running at 11 megabits per second per second. 802.11g was your update to be, still running at 2.4 GHz, but updating the throughput to be 54 megabits per second 802.11n can use 5 GHz, 2.4 GHz, or both of those simultaneously. We can have up to four streams at 150 megabits per second per second for a total of 600 megabits of throughput. And the 802.11ac a standards is a 5 GHz standard, with eight streams running at 866.7 megabits per second per second, giving us a total maximum theoretical throughput of nearly seven gigabits per second.

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Category: CompTIA A+ 220-901

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