ok so 1 frame = 16.6667 ms (ping)

1 buffer= 0.5 frame of input lag

since ping is a measurement of a two way trip, the goal of buffer is to delay the game just long enough to receive inputs from your opponent. a one way trip

therefore when you set buffer you calculate it with your ping 1 buffer for every 16.666 ms

and what that does is delays for half a frame on both sides 8.3333ms each person so they can receive inputs and render them