By some gameservers you can not connect to a server wenn you have a dailup (modem) connection.
Is it a idea that a server can select a option, that a player with a high ping can't connect to the server.
Or the player need to have for example: 512mbit/s down- and 64mbit/s upload.
Or you are not alowed to enter wenn you have a dialupconnetion.
Its maybe nasty for the slower gamers, but the players with a good connection will have fewer lag.