OnOffApplication

OnOffApplication is a traffic generator used in network simulations, most notably in the NS-3 discrete-event network simulator. It models bursty traffic by alternating between on periods, when data is transmitted, and off periods, when no traffic is generated. The application is typically configured to run over a UDP or TCP socket, depending on the simulation setup, and emits packets only during the on state.

During on periods, the application sends packets at a specified data rate and packet size to a configured remote address and port. During off periods, transmission stops completely. The state transitions are driven by timers, which can be set to fixed values or drawn from randomized distributions to reflect variability in traffic patterns.

Key configurable parameters include OnTime and OffTime (durations of the on and off states, which may be constant or randomized), DataRate (the transmission rate during on periods), PacketSize (payload per packet), and the remote endpoint (address and port). StartTime and StopTime can be used to control when the application begins and ends. The component owns a socket and handles the scheduling of packet transmissions and state switches.

OnOffApplication is widely used to study network performance under bursty traffic conditions, including effects on queueing, throughput, latency, and protocol behavior. It provides a flexible, lightweight means of generating controllable traffic loads and can be integrated with various network topologies and simulation scenarios in NS-3. See also NS-3’s OnOffApplication documentation for implementation details and usage examples.