ipv4 is an 32 bit addressing means (2^32 ) ip address can be produce,but the useage of ipv4 address were increased so they came to end.to over come this problem they introduced the concept of ipv6. it has 2^128 addressing bits.
5 key concepts of ipv6.
1.statefull Stateless; Link-Local and Site-Local addresses, also ND (Neighbor Discovery)
IPv6 is based on IPv4, it is an evolution of IPv4. So many
things that we find with IPv6 are familiar to us. The main
1.Simplified header format. IPv6 has a fixed length header,
which does not include most of the options an IPv4 header
can include. Even though the IPv6 header contains two 128
bit addresses (source and destination IP address) the whole
header has a fixed length of 40 bytes only. This allows for
Options are dealt with in extension headers, which are only
inserted after the IPv6 header if needed. So for instance if
a packet needs to be fragmented, the fragmentation header is
inserted after the IPv6 header. The basic set of extension
headers is defined in RFC 2460.
2.Address extended to 128 bits. This allows for hierarchical
structure of the address space and provides enough addresses
for almost every 'grain of sand' on the earth. Important for
security and new services/devices that will need multiple IP
addresses and/or permanent connectivity.
3.A lot of the new IPv6 functionality is built into ICMPv6
such as Neighbor Discovery, Autoconfiguration, Multicast
Listener Discovery, Path MTU Discovery.
4.Enhanced Security and QoS Features.
IPv4 means Internet Protocol version 4, whereas IPv6 means
Internet Protocol version 6.
IPv4 is 32 bits IP address that we use commonly, it can be
192.168.8.1, 10.3.4.5 or other 32 bits IP addresses. IPv4
can support up to 232 addresses, however the 32 bits IPv4
addresses are finishing to be used in near future, so IPv6
is developed as a replacement.
IPv6 is 128 bits, can support up to 2128 addresses to
fulfill future needs with better security and network
related features. Here are some examples of IPv6 address: