IPv6 world launch day is on 8 June 2011 , next event held on 6 June 2012.
Here I am listing main difference between the two protocols.
1) IPv4 : RFC 791
IPv6 : RFC 2460
2) IPv4 : Address size : 32 bits
IPv6 : Address size : 128 bits
3) IPv4 : unicast, multicast, broadcast
IPv6 : unicast , multicast ( some changes ), anycast
4) IPv4 routers : Does Fragmentation
IPv6 routers : No fragmentation (Pv6 host should perform path mtu discovery or do end-to end fragmentation)
5) IPv4: default PATH MTU 68
IPv6 : default PATH MTU 1280
6) Minimum datagram which host should accept : IPv4 : 576
IPv6 : 1280
7) Payload limit : IPv4 : 65535 ((216−1)
IPv6 : 4294967295 (232−1) , known as Jumbograms
8) IPv4 : TTL ( Time to Live)
IPv6 : Hop Limit ( same functionality only name change)
9) Header :
a) IPv4 : check sum present
IPv6 : No check sum
b) IPv4 : Includes "option"
IPv6 : Separate " extension header" not in IPv6 header
c) IPv4 : IPsec optional
IPv6 : IPsec compulsary
10) IPv4 : Address ( Manual/DHCP)
IPv6 : Stateless auto configuration ( link local)
11) IPv4 : To resolve IP->MAC -> ARP broadcast
IPv6 : To resolve IP->MAC -> Multicast solicitation messages ( neighbor discovery protocol)
12) IPv4 -> Broadcast to all hosts
IPv6 -> Link local all nodes multicast group ( to send to all nodes)
