Wi-Fi Top Tips for Schools
With our experience in performing installations of wireless networks into schools, I have listed below some guidelines to the do’s and don’ts when designing and managing a wireless network for a school.
Wireless PIR Motion Sensors – These are often found in schools to regulate lighting systems, and some come with wireless connectivity to connect back to a receiver. Avoid using ones which use 2.4Ghz and 5Ghz, as this can cause high interference issues with your wireless network.
IP Ranges/LEA (Local education authority) limits and how to extend – A school is generally allocated a number of IP addresses to use, which determines the max number of users that can connect to the network. This limit can be smaller than desired. Contact the LEA (Local education authority) to request more IP addresses, which normally takes 4-6 weeks to turn around.
Number of users per classroom – A typical classroom will have 30 or more wireless devices. If you have a BYOD (Bring Your Own Device) policy that number can more than double as students can bring in their own smartphone, laptop, and tablet at the same time. Ensure you have the capacity in your network to cope with an exponentially growing number of devices at your school. We recommend using Ruckus Wireless, as they are the market leader in terms of capacity and throughput speed.
Horizontal fitment of Access Point's – Most access points are designed to be mounted horizontally, as the orientation of the antenna inside are designed to sit that way. While fitting them vertically on a wall will give you a connection, you may face problems in performance as the polarization of the antennas will not be correct when sending and receiving wireless signals.
Have the correct number of access points – If you are installing a new wireless network or upgrading an existing wireless network, having the correct number of access points is essential. This can be achieved by having an on-site survey performed taking actual physical radio frequency strength readings and incorporated into a design, also called a passive survey. Do not be fooled by a predictive survey, which is a simulated analysis for a wireless deployment, as they do not take into account many variables that can only be achieved by a passive survey. Having too little access points can lead to coverage holes and lack of capacity. Having too many access points can be detrimental, as it can cause co-channel interference with neighbouring access points and therefore drop in connectivity. We consider that survey to be the most important part of the wireless installation.
Advantages of using dual band access points – Using dual band access points will give you the advantage of doubling the capacity of a single access point. All wireless devices use 2.4Ghz radios to connect to a wireless network. Some are dual band which incorporate a 2nd 5Ghz radio chip to connect as an alternative. Having a dual band access point that can use both radios at the same time will double the number of potential connecting users without the added cost of buying more access points and redesigning the network. If you don't need the capacity now, you may well do in the future as most schools increase the required capacity with additional laptops and tablets, as well as the incorporation of BYOD (Bring Your Own Device) policy to the school.
Why not 802.11ac (at the moment), 802.3at power and Multi-User MIMO – Upgrading to the latest 802.11ac standard for access points may seem like a good idea at the moment, but being an early adopter of this new technology has its price to pay. 802.11ac requires PoE switches that are 802.3at compliant to power that AC standard of access points to reach their full potential. As most schools will have 802.3af switches as standard, an upgrade in switches will be required to take advantage which can be a massive cost to account for in the schools budget. See our blog written by my colleague Darren on this subject matter here.
The 802.11ac standard is in its infancy at the moment also, meaning that most access points with this standard are at wave 1. Wave 2 is due sometime in the future, but current 802.11ac hardware is limited to wave 1. The major difference between wave 1 and wave 2 is a technique called multi-user multiple-input-multiple-output, or multi-user MIMO, which wave 1 does not have. 802.11n and Wave 1 802.11ac have standard MIMO, which allows for multiple streams to be sent, but only to one user at a time, and most devices don't allow for this, so the bandwidth upgrade you get for using 802.11ac is wasted (may as well stick to 802.11n!). Wave 2 however uses multi-user MIMO, which allows for different streams to be sent to different users at the same time, even devices without MIMO, thus maximising the potential of the 802.11ac standard and its high bandwidth gains over 802.11n. As Wave 2 has not been released, there is little point in upgrading to the 802.11ac standard at this current time.
These are but a few pointers, there are many more that I have not listed here, some simple, some incredibly complex in nature, but the above serve as a guideline to some common issues we face on a daily basis.