According to the recent observations of IPv4 (Internet Protocol version 4) address allocation status, it will be running out within few years. Consequently, to ensure the continuous extension of the Internet operation, introducing IPv6 (Internet Protocol version 6) protocol is surely needed. But at the same time, such transformation must be "smooth" for every Internet users and be compatible with today's IPv4 based practices. This paper describes several techniques and usage scenario which are discussed mainly in the IETF -- Internet Engineering Task Force -- and tried to be implemented as prototype products to transform today's Internet towards the IPv6 based one.