Constantly-updated metadata describing network traffic which is continuously streamed to collection/analysis systems such as NETSCOUT Sightline. It is the industry-standard form of network telemetry used to detect, classify, and traceback DDoS attack traffic, and scales to provide visibility into network traffic on the largest networks in the world. Cisco NetFlow, IETF IPFIX, s/Flow, and Juniper cflowd are examples of flow telemetry