A gateway apparatus for interfacing an access network 1 to a service network 3, the apparatus comprising an input for receiving access requests from the access network at a first flow rate, an output for forwarding access requests to a gateway controller at a second flow rate, and a flow controller for controlling the flow of access requests from said input to said output. The flow controller comprises a receiver for receiving a restrict ion value from the gateway controller, first processing means for determining whether the received restriction value is more restrictive than any currently in use restriction value and, if so, for determining a leak rate on the basis of the received restriction value and the current second flow rate, and second processing means for allowing access requests to pass to said output at a rate up to the determined leak rate at least until a further restriction value is received.