There's no clearer demonstration of boarding you'll ever see in a game.
I feel like that hit is one that you will see in a referee's training seminar.
"Folks, this is as clear an example of boarding as we can show you. 19 Red has the puck, is facing the boards, and 11 White hits him directly in the numbers. Notice the follow through on the check and 19 Red crash head first into the boards. Dangerous play and cannot be tolerated."