WiMAX stands for Worldwide interoperability for Microwave Access. Multimedia applications are gaining much of the user attention with the introduction of new broadband technologies. VoIP is the most well-known service of WiMAX and is a growing rapidly in world of telecommunication. Not only for improved quality but for also a wide range the authors prefer wireless networks. As in wireless networks nodes are mobile mean they can move freely so in paper basic analysis is done on the performance under nodes failure, as they are mobile so there are chances that nodes can be failed so in case of failure, what is its effect on the entire performance of the network has been analyzed.