During your device test in the setup of the online lesson space, we check your internet speed, what browser you use, the type of camera device and microphone you use so that we can advise you and offer a more tailored assistance should problems arise. Part of the internet speed test is to also measure two metrics called ping and jitter.
Ping, also called delay or latency, is the time it takes for a bit to be transferred from the source to the destination. It indicates the responsiveness of the connection and is independent from the download and upload speeds which indicate how fast you can pull and push data from/to the server. Jitter on the other hand is the variation in ping and can be visually represented as the distance between the data packets. They are both measured in ms(milliseconds) and the higher the value, the more unstable the network will be.
When a static website is loaded in your web browser, data does not have to arrive in order. Think of it as a puzzle - it doesn't matter which piece you put first and which one goes last. As long as you have all the pieces you get the whole picture. It's the same with a normal web page. Also, if any pieces are lost in transit, you can always ask for them again to complete your puzzle. In this case ping and jitter are not so relevant. They can slow down the web page loading but you'll eventually have it on your screen. Any data that is missing can be recovered by asking the server to send it again.
When live video and audio communication happen however, ping and jitter are crucial. Data packets have to arrive in precise order and if anything arrives late, it is automatically discarded as it is no longer needed.