One of the most recognizable differences between IPv4 and IPv6 is the size of the address space. IPv4 has 32 bits and allows for approximately 4 billion hosts (4 x 109). IPv6 has 128 bits and allows for approximately 340 undecillion (340 x1036) addre...
http://www.ebrahma.com/2013/09/understanding-basics-ipv6-address-representation/Labels: IPv4-vs-IPv6, IPv6, What-is-IPv6