Optimatch
From Halopedia, the Halo wiki
Optimatch is an option on Xbox Live matchmaking. You select the type of game you want to play (I.E. Slayer, Team Slayer, BTB Skirmish), and the system matches you with other people who are the same level area as you.
This is how ranked games are played and you raise your level. This way the point-match system takes effect and it is directly connected to Bungie.net where your stats can be reviewed. Optimatch is located above the create match option on the main menu.
