Abstract :The next-generation Internet Protocol, initially known as IP Next Generation (Ipng), and then later
as IPv6, has been developed by the Internet Engineering Task Force (IETF) to replace the current Internet
Protocol (also known as IPv4). Which offers 2128 possible addresses to enable the integration of IPv6 into
current networks, several transition mechanisms have been proposed by the IETF IPng Transition Working
Group? This work examines and empirically evaluates two transition mechanisms, namely IPv6 to IPv4 tunneling
and dual-stack mechanism, as they relate to the performance of IPv6. The primary focus of this paper is to
compare and analyze IPv4 and IPv6 networks, study their characteristics and header formats. The paper also
attempts to outline the key deployment issues and security-related challenges which are being faced and dealt
with during the migration process