IPv6 is a new version of IP which is designed to be an evolutionary step from IPv4. It is a natural increment to IPv4. It can be installed as a normal software upgrade in internet devices and is interoperable with the current IPv4. and Ubiquitous is commerce done in anyway, anywhere, anytime, and in every aspect. Since the ubiquitous service is not yet implemented but under development. IPv6 is a new version of IP which is designed to be an evolutionary step from IPv4. This paper describes the concept and classification of IPv6 and compares it with IPv4. IPv6 is a new version of the Internet protocol, designed as the successor to IPv4. This paper suggests critical success factors of IPv6 for ubiquitous.