There are many issues with IPv4 which leads to development of IPv6 protocol. Some of them are:
- Adress depletion
- Internet routing table expansion
- Lack of true end-to-end model (NAT in IPv4 necessary)
Features of IPv6
- Larger address space – IPv6 addresses are 128 bit. This number is so big that you can allocate every molecule on the earth and you will still left some addresses.
- Elimination of Public to Private NAT – allows end-to-end communication
- Elimination of broadcast address – IPv6 includes unicast, multicast and anycast (one to nearest)
- Simplified header – improve routing efficiency for performance, no requirement for processing checksums, simpler and more efficient extension header mechanism, flow labels per flow with no need to examine the transport layer to identify the traffic flow
- Support for mobility and security – mobile ip and ipsec built-in.
- Mobility enables people to move around different networks with mobile devices without any breaks. Because IPv4 does not automatically provide this kind of functionality, additional configuration is required.
- In IPv6 mobility is build in which means any IPv6 node can use it when necessary without any additional configuration.
- Transition richness – There are variety of ways to transition IPv4 to IPv6. Including Dualstack, IPv6-toIPv4 tunneling or NAT-PT (Protocol Translation).
- Stateless auto-configuration – IPv6 provides address autoconfiguration from devices data link layer address for plug and play functionality
- Prefix renumbering – IPv6 simplifies for adress and prexif renumbering. The router advertise new prefix and the other devices on the network can begin to use the new info. This process can be made non-disruptive by manipulating valid and preferred timers for each IPv6 address
- Multiple addresses per interface – IPv6 interface can have multiple addresses assigned on same time and can be used simultaneously
- Link-local address – IPv6 automatically create a link-local address on each interface, these addresses are used for many purposes. For example, the interior gateway protocols are using Link-local addresses as the next hop when they are exchanging routing updates
- Provider dependent and provider independent addressing – Enterprises can use IP from provider or use their own provider independent addressing space
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