A method and node for supporting PDSN load optimization in a CDMA2000 network. The Packet Core Network Manager calculates network statistics and uses the resulting numbers to set the PPP inactivity timer depending on the load on the PDSN. In a preferred embodiment, the calculation gives the mean value of the durations of the PPP sessions (KPI1), and the corresponding standard deviation (KPI2). The PPP inactivity timer is then set to M*(KPI1+KPI2) during low load, to M*KPI1 during normal load, and to M*(KPI1−KPI2) during heavy load, where 0<M<=1, preferably depending on the distribution of the subscriber inter-arrival time.