What is "kaillera"

Kaillera is middleware designed to aid networked multiplayer play for emulators. The word "Kaillera", also spelled "kaïra", is the verlan of the French word racaille which is used in reference to " hooligans".

Unlike GGPO, a technology and program allowing emulated games to be played over the Internet, Kaillera suffers from input lag which results in the player's actions being delayed more the higher the delay in a connection is. This is accentuated by the fact that when not using the Kaillera P2P modification, two players have to be connected through a server, thus increasing the delay of the connection.