In a telecommunications network including a gateway network element in communication with a control system and a user device, a system and method of controlling a data consumption rate of the user device including: a first control system node periodically transmitting a command to a second control system node, the message including information relating to a user's data usage, received from the gateway network node; in response to each command, the second control system node transmitting a reply message to the first control system node; controlling the transmission of the periodic commands according to a variable time interval; and the second control system node using the data usage information received in the periodic reply messages to control the data consumption of the user device. Preferably the control system conforms to a 3GPP Policy Charging Control Architecture and the first node is a PCEF and the second node is a PCRF. It is also preferable that the command is a DIAMETER protocol Accounting Request (ACR) command and the reply message is a DIAMETER protocol Accounting Answer (ACA) message.