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WHY SCHOOLS NEED 4th GENERATION WI-FI EQUIPMENT (BUT YOU DON'T NEED IT AT HOME) |
1st and 2nd Generation Wi-Fi
When Wi-Fi technology first emerged a few years ago (and this has become designated 1st Generation Wi-Fi networking) each access point (AP) was a separate little island of wi-fi networking. The Wi-Fi client (the laptop, PDA etc.) negotiated the connection between itself and its AP island. Each AP also needed to be individually configured. Some time later APs were developed which could be configured from a central point, e.g. they could be configured by your Internet Sevice Provider; these became known as 2nd Generation APs, but they remained fundamentally separate islands of Wi-Fi with the client in charge of negotiating the Wi-Fi relationship. This is the status of all APs used in the home.
| This works perfectly well in the home because firstly the home represents a single very well defined island, and secondly there is a very small nuber of clients negotiating for connection, so not much squabbling is going to break out. |
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Why are Schools Different?
It is inherent in Wi-Fi that only one client can communicate with the AP at any one time.With 1st. and 2nd Generation Wi-Fi equipment the clients compete with each other for airtime to connect to the AP. This really doesn't matter much at home, but let's now consider a classroom full of students.
As an analogy we can consider the Wi-Fi environment just like a classroom; in this analogy the teacher is the AP, the students are the clients, and the teacher can only speak to one student at a time; in order to become the one student to get to speak to the teacher, the student has to put his hand in the air and say "me miss, me miss, me miss..); having got the teacher's attention the student and teacher can then speak with each other. This process might not matter much in the middle of a lesson when the majority of students are settled down to coursework, but it is a massive problem at the start of the class when the teacher has to do a register of the students. All 30 students are yelling "me miss, me miss, me miss" and the teacher really struggles to find a quiet moment to open a dialogue with one particular student.
This is EXACTLY what happens when a classroom full of students all try to log on with their laptops at the start of a class. The technical term is "contention", and all the clients have to contend to make an association with the AP (this is the equivalent of doing the register). The contention with 2nd. Generation APs is so severe that it can take up to 30 minutes to get 30 clients registered.
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4th Generation Wi-Fi equipment soves this problem by putting the AP in charge of scheduling air time to the clients on a fair and even basis, so that the client-led contention problem is completely removed. |
To return to our teacher and student analogy, it is as though the classroom full of students sits quietly (as if ! ) and the teacher makes his way round the class giving each student his chance to speak, in turn.
Other Things that 4th Generation does, which you don't need at home
There are 2 main things.Firstly 4th Generation allows you to roam between APs with no problems. 2nd Generation has problems with its "islands". Secondly 4th Generation potentially means you need fewer APs in congested areas such as cafeterias which means you save cost, and you push out less Wi-Fi signal into the air, never a bad thing in this health and safety conscious age. How 4th Generation equipment does these two things must be left for a later Newsletter.
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