Voice and data transmission are fundamental aspects of the information age we live in. yet until recently we have relied on very different networks to deliver voice and data. As a result, the ways in which we interact with these networks are far from seamless. Voice over IP packet (VoIP) is just beginning to deliver on the promise of integrated voice and data services. This convergence of services will allow us to work more efficiently and powerfully than over before. Voice over IP packet (VoIP) networks are integrated multi-service networks that carry both voice and data. This report focuses on understanding the requirements and architecture of VoIP networks and explains some of the issues involved in maintaining good voice quality.