The Internet Protocol (IP) is the most widely used communications protocol. The Internet Engineering Task Force (IETF) is the organization responsible for defining the Internet Protocol standards. When the IETF developed IPv4, the global expansion of the Internet and the current Internet security issues were not anticipated. The Internet Protocol Version 6 is developed to provide new services and to support the Internet's growth. IPv6 is designed to achieve simplicity, increased routing speed, improved QOS and inbuilt security. Due to the current scalability and complexity of the Internet IPv6 becomes mandatory. Because IPv4 is not compatible with IPv6, transition technologies play a major role in making communication between the two protocol suites.