ATC (Augmented Traffic Control)
“A tool to simulate network conditions.” “Developers can use ATC to test their application across varying network conditions, easily emulating high speed, mobile, and even severely impaired networks.”
Developed by Facebook.
Supports Linux.
Comcast
“Simulating [varying] network connections so you can build better systems.”
Supports Linux and MacOS.
netem
“netem provides Network Emulation functionality for testing protocols by emulating the properties of wide area networks. The current version emulates variable delay, loss, duplication and re-ordering.”
Supports Linux.
dummynet
“traffic shaper, bandwidth manager and delay emulator”
Supports *BSD and MacOS.
Note for MacOS, ipfw was deprecated in OSX 10.10 and replaced with pfctl. Documentation is few and far between. dnctl is utilized to control dummynet on MacOS. YMMV.
tc (Linux Traffic Control)
A comprehensive overview of traffic control capabilities on Linux systems.