I happen to have two home Internet connections, Comcast and AT&T. I’ve found this can be quite handy when everyone in the family is streaming or gaming or if one of them is experiencing problems of one type or another. I use pfSense as my main router and firewall. It does a pretty good job of being able to load share across each connection so that they are both used at the same time and then do automatic failover when it notices a problem with one or the other. The way it “monitors” the connection is to ping some outside host and if it notices a high amount of loss or latency, remove that connection from path. When loss or latency improves it will add the path back in. Pretty handy.

If you’re not familiar, smokeping is a tool that helps visualize loss and latency to a given destination. It will ping a list of hosts about 20 times every 5 minutes and then, on a web page, show a graph that displays the average latency and will also indicate any packet loss. The really handy thing is the history that it keeps. By default you get 4 graphs; a 3 hour, 30 hour, 10 day, and 360 day view. This lets you immediately spot outliers and gives you context as to the magnitude.