IPv6

Internet Protocol version 6 (IPv6) refers to the next-generation Internet protocol as a protocol of the network layer. The Internet has been deployed with IPv4 protocols, but the limited address space of the IPv4 protocol(32 bits) occurs and the limit of the country's allocation of addresses is almost exhausted. As an alternative to this, IPv6 protocols have been proposed, international standards have been established through RFC, and in fact IPv6 addresses have been assigned and applied to mobile phones and computers. 

The biggest difference between IPv6 and traditional IPv4 is IPv4 provides 32 bits of address space, but IPv6 provides 128 bits of address space. IPv6 address space can provide address space for large amounts of ubiquitous communication devices to emerge on the Internet in the future. Also, IPv6 hosts can automatically allocate a network address when they connect to an IPv6 network. This is an important advantage over IPv4, which was given an IP address by a network.

The 128-bit address space in IPv6 is represented by eight digits, representing a 16-bit (2 octet) in hex. For example, address looks like 2001:0db8:85a3:08d3:1319:8a2e:0370:7334. However, since most digits have a number of zeros, it is possible to abridge 0000 to one 0, or remove a group of zeros altogether and leave only ' : ‘. For example,  address express like 2001:0DB8:0000:0000:0000:0000:1428:57ab to 2001:0DB8::1428:57ab.

Because IPv4 is used a lot now, method to maintain compatibility between IPv4 and IPv6 is needed. The IPv4 / IPv6 dual-stack is the easiest way for an IPv6 node to remain compatible with a dedicated IPv4 node. There is also a tunneling system. Tunneling is a method by which IPv6 datagrams are encapsulated in IPv4 packets by IPv6 hosts and routers and transmitted through IPv4 routing topology areas. Tunneling provides a way to transport IPv6 traffic by utilizing existing IPv4 routing infrastructure.