Needing to simulate delay to test an application ability to fill a pipe in the prototype lab, I needed to emulate the latency to get a more realistic view. The blog post from Benjamin Cane (tc: Adding simulated network latency to your Linux server) got me onto this method. I also found tc man page & ArchLinux Advanced Traffic Control Wiki useful for a deeper dive.
Also see my previous post on Toxiproxy - WAN simulator of sorts!
Also see my previous post on Toxiproxy - WAN simulator of sorts!