After trying to figure out why our DSL (10mbps) was virtually useless most nights about 9pm, I finally figured out that it was an iPhone (64gb) set to do an iCloud backup which tries to happen when it's plugged into power. Apparently it was using all our upload bandwidth and severely limiting any network traffic in the evening. My daughter didn't even mean to use iCloud backup. Hopefully this will help others. It wasn't obvious with 5 of us in the house what was going on.