The key QoS parameters for VoIP are delay, jitter and loss. In the Internet, VoIP requires the underlying packet switched network to minimize the impact of these parameters. A major contributing factor in this regard is traffic engineering carried out by scheduling algorithms. This paper studies the behavior of different types of scheduling algorithms on the delay, jitter and loss QoS parameters. The performance evaluation involves identifying the scheduling algorithms which are most suitable for VoIP communications. The result from the analysis also shows the impact of the QoS parameters on VoIP over the internet.