The Source app is a synthetic packet generator. On each breath it outputs 1,000 new packets to each attached output port. The packet data is uninitialized garbage and each packet is 60 bytes long.

The Join app joins together packets from N input links onto one output link. On each breath it outputs as many packets as possible from the inputs onto the output.

The Split app splits packets from multiple inputs across multiple outputs. On each breath it transfers as many packets as possible from the input links to the output links.

The Sink app recieves all packets from any number of input links and discards them. This can be handy in combination with a Source.

The Buzz app simply prints a message to stdout each time a callback runs. This can be useful for observing the execution of the app framework in a primitive way.