Load balancing means taking two internet connections and feeding them into your network to get a double speed connection. This is a more resilient internet connection. Here you need to choose two independent internet providers. Now the load balancing hardware will automatically use the line with least load. So it is clear that if by any chance one line fails then the second line will automatically be taken up. The load balancing hardware is tunes to use only the line that has the minimum load so that the internet connection is faster and available. If one line is fails then load balancing hardware is tuned to identify and put to use the line that is active.