A non-interactive introduction to the spanning tree protocol

Imagine you rent office space for a three-day event. You quickly set up a few Ethernet switches and tape some cables on the floor to get everyone online. Unfortunately, Stan, your clumsiest coworker, kicks out a cable every time he gets up for coffee. Spare cables would fix that, but a loop turns into a broadcast storm: Ethernet packets multiply until nothing else gets through. That’s where the spanning tree protocol comes in: it blocks just enough of the spare cables to leave a loop-free tree, and rebuilds it in a second each time Stan strikes again. This content is also available as a text version, with interactive demos that run a real implementation directly in your browser! This video is an experiment.1 Honestly, except for Radia Perlman reading her poem,2 you should read the original article instead. It presents the same content, but you can play with the interactive examples, which are the main contribution. On the other hand, if you happen to like the video, be sure to tell me…