What is the ping pong?

this game is to hit a ball from one field to another on the network, until one player misses the ball or hit it over the net or outside the mesa.lo which is considered point for the opponent.
each player has 5 services, the first to score 21 points is the winner.
also can be played in pairs, the game is the same as if it were individually what changes are services, their services are crossed.