Virtualization is the central point empowering cloud infrastructure. Many services, such as web-based applications, databases, and instant messaging servers, are running on virtual systems to reduce total cost ownership and generate immediate return on investment. However, applications concerned with latency, such as the Voice over Internet Protocol (VoIP) application, are limited in virtual systems. Hence, in this research, we aim to study the VoIP behavior under virtualization environment. VoIP infrastructure should be equipped with security shield to protect itself from various forms of security threats; this security setup provides additional response time overhead. In this study, we implement VoIP on a virtual machine (VM) and measure various elements, such as signaling and medium transmission. The performance of the proposed system is studied with and without security shield. Virtualization environment never induces delay to the VM–VoIP system, even if it is deployed with security solutions.