YOU’LL NEED THIS

WINDOWS PC

Wi-Fi Router Time required: 1 hour

WHEN DATA IS SENT across the internet, it rarely travels in one big chunk. Instead, every email, photo, or streamed song is chopped into smaller pieces called packets, which bounce from one server to the next until they reach your PC. There’s no guarantee they will all take the same route, nor that they arrive in the right order. Therefore, each packet carries additional data, a bit like the address on an envelope, that makes clear which other packets it goes with, and where it fits in the overall collection. Your computer uses this data to reconstruct the original file or stream, before sending it on to the email client, photo viewer, or audio player that requested it.

For the most part, it works, and pictures and messages routinely arrive uncorrupted but every so often, packets get lost along the way or may miss their slot. That’s not really a problem with emails, which can wait a few milliseconds to give the missing data a chance to catch up, but streaming is inherently time-sensitive, so packet loss is more obvious. If your video-calling software has to wait for delayed packets, you may notice the stream freezing and, if they never arrive or miss their slot entirely, you might see glitches and momentary blackouts. In the worst case, the software may give up entirely and cut the call. Packet loss can happen anywhere on the data’s journey and, if you’re regularly suffering from this, you should diagnose where the problem is occurring and, if it’s your own network, do something about it. –NIK RAWLINSON