P can then be determined as a function of average drop rate p and average round trip time R: P = A ( p , R ) = { R ( b 2 W ( p ) + 1 ) + Q ( p , W ( p ) ) F ( p ) T 0 1 - p if W ( p ) < W max R ( b 8 W max + 1 - p p W max + 2 ) + Q ( p , W max ) F ( p ) T 0 1 - p otherwise Since P is a function of p and R, P can take multiple values depending on traffic conditions.