RFC 2722 defines traffic flow as "an artificial logical equivalent to a call or connection.
A flow could consist of all packets in a specific transport connection or a media stream.
"[2] Flow is also defined in RFC 3917 as "a set of IP packets passing an observation point in the network during a certain time interval.
"[3] Packet flow temporal efficiency can be affected by one-way delay (OWD) that is described as a combination of the following components: Packets from one flow need to be handled differently from others, by means of separate queues in switches, routers and network adapters, to achieve traffic shaping, policing, fair queueing or quality of service.
Applied to Internet routers, a flow may be a host-to-host communication path, or a socket-to-socket communication identified by a unique combination of source and destination addresses and port numbers, together with transport protocol (for example, UDP or TCP).