Ipv6 Versus Ipv4

BACKGROUND
In computer networking, particularly when discussing TCP/IP, IP addressing is very paramount. An IP address is a numeric identifier assigned to each machine on an IP network. An IP address is a software address, not an hardware address- the latter is hard-coded on a network Interface Card(NIC) and used for finding hosts on a local network. IP addressing was designed to allow host on one network to communicate with a host on a different network, regardless of the type of the LANs the hosts   are participating in. The Internet Protocol version 4(IPv4) has been used for many years in IP addressing , but recently specifically   in December 1998, the Internet Protocol Version 6(IPv6) was defined and born with the intention of making it a replacement for IPV4.
THE NEED FOR IPv6
The main driving force for the redesign of Internet Protocol is the foreseeable IPv4 address exhaustion. IPv6 was defined in December 1998 by the Internet Engineering Task Force (IETF) with the publication of an Internet standard specification, RFC 2460. The first publicly used version of the Internet Protocol, Version 4 (IPv4), provides an addressing capability of about 4 billion addresses (232). This was deemed sufficient in the early design stages of the Internet when the explosive growth and worldwide proliferation of networks was not anticipated.
During the first decade of operation of the TCP/IP-based Internet, by the late 1980s, it became apparent that methods had to be developed to conserve address space. In the early 1990s, even after the introduction of classless network redesign, it became clear that this would not suffice to prevent IPv4 address exhaustion and that further changes to the Internet infrastructure were needed. By the beginning of 1992, several proposed systems were being circulated, and by the end of 1992, the IETF announced a call for white papers (RFC 1550) and the creation of the "IP Next Generation" (IPng) area of working groups.
Estimates of the time...