High-availability, scalable policy and charging control systems, and methods therefor

In a method carried out by a first and second policy and charging rules functions (PCRF) (201, 202), the first PCRF receives (s10), from a policy and charging enforcement function (PCEF) (100), an IP-CAN session establishment indication, determines (s20) first policy decision information, causes (s30) a database (300) accessible by both PCRFs to store, in association with a session identifier, session information comprising the session data and the first policy decision information; and provides (s40), to the PCEF, the first policy decision information. Later, the second PCRF receives (s50), from the PCEF, a session modification indication, obtains (s60) therefrom the session identifier, retrieves (s70), from the database, the session information, determines (s80) second policy decision information; causes (s90) the database to store session information comprising the modified session data and second policy decision information; and provides (s100), to the PCEF, the second policy decision information. The invention also relates to a system putting into practice such method.