An IP (Internet Protocol) diagnostic system is provided for troubleshooting data transport quality over an Internet Protocol operating in a communication system (100). The IP diagnostic system includes one or more processors (106) each placed at different segments (108) in the communication system. Each processor is programmed to receive (206) a request to establish a test session with a corresponding test node, establish (208) one or more IP connections with the test node, carry out (210) the test session with the test node on said IP connections, and measure (212) a quality level for each of said IP connections.