Jmeter is de facto in telecom , it's far from perfect but it let you define complex flows quick , the pain is that you need to ménage the test plans on the serv

Jmeter is de facto in telecom , it's far from perfect but it let you define complex flows quick , the pain is that you need to ménage the test plans on the server to run all the jmx files I wish there was full web interface on the server already