Why is my school's wifi so slow?

You might as well have asked “why is my wifi so slow?”.

Slow wifi is generally caused by the same things regardless of the environment:

• poor channel planning causing co/adjacent-channel interference
• poor RF engineering
• too many clients devices per AP
• too many devices per channel
• RF interference
• cheap hardware

There are additional factors that can cause problems that are unrelated to the wifi, and will affect the network as a whole:

• overloaded switch uplinks
• insufficient address space
• overloaded DHCP server
• overloaded DNS server
• insufficient bandwidth to the internet
• insufficient firewall performance

This is why it’s important to spend the money to properly design your wireless network before choosing a vendor and buying a bunch of equipment. Isto é particularmente importante em ambientes escolares onde há muito dinheiro "grátis" do governo flutuando por aí para financiar estes projetos. Existem fornecedores inescrupulosos que simplesmente lhe dirão para comprar um AP para cada sala de aula e colocá-lo lá, sem nenhum planejamento adicional. Esta é inevitavelmente uma receita para o mau wi-fi.