A Brief Word About Flows

Packets can be grouped in multiple ways:

Temporal Proximity
Flows are separated by `idle' periods
Also called `timeout-based' flows
Good for tuning caches in routers and switches

Transport Layer Signaling
Flows encompass all packets from a particular connection
For TCP, this is all packets from the initial SYN to the final ACK
Most relevant for end-to-end measurements
This isn't a valid definition for all protocols...