I was recently troubleshooting a network that had an internet modem connected to an Apple Airport that connected to a switch and another switch was connected to that switch. The internet started going down every 20 minutes and I thought it was a bad switch because when I plugged my laptop into the AirPort the internet worked for me. However, it ended up being a loop which was causing the internet to go down. I had a thought that it might be a loop but I wouldnt have really known because I dont really know what it means and what causes it.
Can you please clearly explain to me (like I'm in grade school) what a loop is and how to fix it?