##### TCP Timers formulae

1.RTT Deviation =*R**T**T*_{D}=(1-*R**T**T*_{D}) old *R**T**T*_{D} + *R**T**T*_{D} * | (*R**T**T*_{S} -*R**T**T*_{M})|

2.RTT Deviation =*R**T**T*_{D}=(1-*R**T**T*_{D)} old *R**T**T*_{D} + *R**T**T*_{D} * | (*R**T**T*_{M})|

Which of the following is right formula for calculation and in what conditions ?I found both formula right in some numericals?

here , IRTT is initial RTT(round trip time), ARTT is actual RTT,NRTT is normal RTT

ID is initial deviation, ND is normal dev. , AD is actual dev.