A telecommunication system can include a network flow controller (e.g., SMF) and a network-charging node (e.g., CHF). The flow controller can generate a first charging-event record associated with a network session. The flow controller can detect an outage at least partly by determining that no network-charging node is available to receive the first charging-event record and, in response, mark the first charging-event record to provide a first marked charging-event record. The flow controller can store the first marked charging-event record in a buffer. After the marking, the flow controller can determine that a network-charging node is available to receive the first marked charging-event record, and, in response, send the first marked charging-event record to the network-charging node. The network-charging node can determine a charging-data record indicating occurrence of an event during the outage.