The National College Athletic Association's rules for overtime in college football say that in the event of a tie game at the end of regulation play, each team gets one possession starting on the opposing club's 25 yard line. After each possession is over, the team with the most points wins the game.
The rules were put into effect in 1996 and before that time, if two opponents were tied, the game was recorded as such.
The rules further state that after the third overtime, teams are required to score a two point conversion to win the game. Safeties aren't permitted and points must be scored by the offense.
Other aspects of NCAA overtime rules for football are that the game clock isn't used, remaining at zero until a victor emerges. The play clock is still used, giving a team 25 seconds to put the ball into play. For each possession, opposing sides only have one time out. If no one scores after one possession, the process starts again in a new overtime period.
The system is widely criticized compared to that of the NFL. In professional football in the event of a tie, a 15-minute overtime is played and if neither team scores, the game is recorded as a tie.