1. A method comprising:receiving, by an access and mobility management function (AMF) from one or more session management functions, one or more first messages indicating user plane connection activations for a plurality of packet data unit (PDU) sessions to deliver downlink user data to one or more wireless devices;
determining, by the AMF, a first time duration based on the user plane connection activations for the plurality of PDU sessions, wherein the first time duration indicates a delay between receiving a downlink data packet and notifying the AMF about user plane connection activation for the downlink data packet; and
sending, by the AMF to the one or more session management functions, one or more second messages to delay the sending of further user plane connection activations to the AMF, the one or more second messages indicating a value of the first time duration.