use ipfw on Mac to simulate slow network traffic (verified on 02/14/2014)

(1) create a pipe which limits the speed to 56kbit/s

  sudo ipfw pipe 1 config bw 56Kbit/s

(2) add the pipe to ipfw list with simple option:

  sudo ipfw add 1 pipe 1 ip from any to any

(3) delete the pipe:

 udo ipfw delete 1

Reference links: (note some of them already been expired, but worth a reading)

mxiayan