1. A method performed by a policy and charging rules node (PCRN) of provisioning event triggers from a requesting node on a primary gateway, the method comprising: receiving, from the requesting node, a request to provision a set of event triggers on a first primary gateway providing a communication session; forwarding, to the first primary gateway, the set of event triggers indicating events that the primary gateway should report to the PCRN; storing the set of event triggers in association with the session; detecting a handover of the session; determining a new primary gateway; and provisioning the new primary gateway by forwarding, to the new primary gateway, the set of event triggers.