L8proxy is a simple tool that sits in the middle of a TCP client/server connection and allows the end-user to apply a time-delay to any of the different parts of the communication.
The default linux tc tool is only able to delay communication over entire network interface and therefore does not allow to single out specific point-of-failures in data flow.
tc qdisc add dev eth0 root netem delay 1000ms
The granular control that l8 provides is achieved by handling each socket using a different thread and means that delaying one end of the communication has no direct impact on the performance of the others.
..
client ===> L8 ---> server
software <--- PROXY <=== software
LEGEND:
===> recv socket
---> frwd socket