Hi,
Please check this, The term peer is used to describe and identify a connection. A connection is two flows. Each flow is a peer of the other.
And with a little bit of Internet surfing you can find that a flow is a sequence of packets from a source computer to a destination, which may be another host, a multicast group, or a broadcast domain. RFC 2722 defines traffic flow as "an artificial logical equivalent to a call or connection."
Remember that a flow itself it's different of the Flow ID: A number identifying a flow within TMM. The same flow ID can be used for different flows in different TMMs. Also, the same flow ID can be re-used for a different flow within the same TMM at a different time.