A network anomaly detector detects a network anomaly by monitoring a communication network and provides an indication of the detected network anomaly to a network anomaly analyzer. The network anomaly analyzer receives the indication of the detected network anomaly and, on the basis of data representing the detected network anomaly and additional data, e.g., from outside the communication network, performs classification of the detected network anomaly. Depending on the classification of the detected network anomaly, the network anomaly analyzer provides a report of the detected network anomaly to another node. If for example the detected network anomaly is classified as expected behavior, reporting of the detected network anomaly may be suppressed.