A penalty, violation, or fault is called on a player who breaks the rules of volleyball defined in a rulebook for the league. Each result in a side out, which is one point and possession of the ball for the opponent.
Players are not allowed to cross or touch the centerline that divides the court in half. You may see the referee call a centerline violation by blowing his whistle and pointing to the line.
If a team causes any unnecessary interruptions or delays they will be given a delay warning the first time and then a delay penalty the second time by the referee.
Players are not allowed to touch the net during a rally. Breaking this rule results in a net violation penalty.
Players can only exit and re-enter the game once per set and must return to his original position. If teams go over the allowed number of substitutions or attempt to change a returning player's position, they will be charged with illegal substitution. This counts as a game delay.