Voice over IP (VoIP), which provides real-time speech communication between two users in a way that closely resembles a face-to-face conversation, has had a significant impact on the multibillion-dollar telecommunication industry. The promise of less expensive phone calls with comparable quality and better features than public switched telephone networks (PSTNs) has accelerated VoIP's adoption, both in businesses and homes. Its better integration with various forms of collaborative communications, such as instant messaging, email, and voicemail, has made it suitable for future communication solutions, but there remain several issues that are unique to VoIP systems and require further analysis.