VoIP applications are being broadly employed in present networks challenging their abilities to offer an experience level of good quality to the users. Specially, new wireless broadband techniques i.e. WiMAX, deployed and their performance requires to assess for checking the performance levels of VoIP services. The quality of service is the primary challenge of implementation VOIP over WiMAX networks. This paper builds an attempt to study the performance measurements of VoIP for static users, as well as, the variation of the quality of service parameters.