WAN emulation is a method of testing application performance using a device to create local, virtual networks that replicate real-world client/server connections. By applying impairments to these packet streams, testers can validate application performance and end-user experience before going live.
Traffic generation is the process of injecting traffic, packets, or data flows into a network in order to test the performance and capacity of devices, protocols, and network topologies. A traffic generator sends test packets containing unique identifiers so they can be tracked throughout the network.