In this blog, we will be looking at some aspects of WiFi (wireless internet for the cavemen in the room) namely the types of 802.11 standards that you will need to know and differentiate in the A+ exam.
First off, let’s look at the 802.11 standard itself, to get a baseline understanding of it. 802.11 was invented way back in 1997 with a bandwidth reaching up to 2 Megabits per second. (For comparison, 1080p video uses 6 Megabits per second, a whole 3x as much as the max of original flavor 802.11)
Strangely, the next one up is not 802.11a, as you might expect, but 802.11b, which was released back in 1999. Something that will be important once we talk about 802.11a is looking at frequency, so for reference both this and 802.11 plain use 2.4 Gigahertz as their frequency. That leads to 802.11b having a bandwidth of up to 11 Megabits per second, far better than the original speed, but still paltry in the modern world’s internet speeds.
Now we finally get to 802.11a, which was also introduced in 1999, but was not widely adopted. It uses a 5 Gigahertz band, which allows more than double the bandwidth of the 802.11b standard. The issue with that however, is that with the same power source, a 5 Gigahertz signal will only go half as far as a 2.4 Gigahertz signal. So if you have nearby devices, it is great for speeds, but the further you go, the worse the speed gets.
Next up, let’s look at a more recent couple of standards, starting with 802.11g, introduced in 2003. It is almost identical to 802.11a, except for frequency. So it has the same speeds (Up to 54 Megabits per second, as I don’t think we mentioned that before for 802.11a) but it uses 2.4 Gigahertz frequency, so it can be just as fast from farther away.
Next up is 802.11n, getting closer to current tech, it was introduced in 2008. This one is interesting as it allows both 2.4 and 5 Gigahertz. So you can use whichever one best suits your needs, faster but low range or slower and further range. The minimum speed, for the first time, is higher than the highest of the previous, being 72 Gigabits per second. The high end of this standard is around 600 Megabits per second (enough to stream about 100 1080p videos at once.)
Now we will finish off the ones you need to know for the A+ exam by looking at the 802.11ac standard, the latest one you need to know, from 2014. This one is a throwback to 802.11a (hence the name) in that it is only available for 5 Gigahertz. Now this one is a huge jump, hitting speeds of almost 7 Gigabits per second, that’s right, a new unit of measure just for this one. But since it is 5 Gigahertz band only, that does limit it to newer devices, as most devices still stick to the basic 2.4 Gigahertz band, as that has been the standard for a while now.
There are a few more new ones that have been introduced that you don’t need to know for the A+ exam, but just for fun, those are 802.11ax ( 9 Gigabits per second) and 802.11bc, which is still in testing phases as of this writing, expected to be rolled out in 2024, reaching speeds of 40 Gigabits per second. That’s right. 40.