After many fans have asked exactly how public matchmaking works inside “Call of Duty: Black Ops 2,” either out of curiosity or through complaints of lag issues, Activision has described the entire process of how their multiplayer system groups players together. Before now the process has been largely secretive, leaving players to speculate why they believe whether they have been placed in a properly ranked match with good connection or not. This has left many players to ask for dedicated servers as opposed to the peer-to-peer setup currently in place. The following steps are how “Call of Duty: Black Ops 2” filters all matches to players during the matchmaking process.
1. Filter all games that can be joined by proximity to the player. Proximity does not adhere strictly to city, state or country as seen on a map. Rather, it breaks down into four tiers of geographical region surrounding the player. The query starts in the tier closest to the player and expands from there if it cannot find enough matches. The query also ignores all full or “non-joinable” games, which could be half or more of the total available games in a playlist.
2. Filter by broad skill range. This step takes the proximity-filtered list and narrows it further to the set of games that fall roughly in the same broad skill range. This is very loose criteria in Public Match and is a broad-stroke filter that avoids games at the extreme ends. A player of very high skill should generally not get matched to games where the average skill of players is very low, and vice versa.
3. Steps 1 and 2 normally take a fraction of a second and result in a list of “top 50” available games. From here, the game tests for the best connection quality of those 50 games. Connection quality includes a measure of ping, bandwidth between you and the host, and NAT compatibility. The game attempts to join you to the game with the best connection quality of all possible matches, starting at the top of the list.