IPv6
 | Parts of this article (those related to RFC 8200 and RFC 8201) need to be updated. (July 2017) |
| Protocol stack | |
 IPv6 header | |
| Abbreviation | IPv6 |
|---|---|
| Purpose | Internetworking protocol |
| Developer | Internet Engineering Task Force |
| Introduction | December 1995 |
| Based on | IPv4 |
| OSI layer | Network layer |
| RFCs | 2460, 8200 |
| Internet protocol suite |
|---|
| Application layer |
| Transport layer |
| Internet layer |
| Link layer |
Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. IPv6 was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated problem of IPv4 address exhaustion, and was intended to replace IPv4.[1] In December 1998, IPv6 became a Draft Standard for the IETF,[2] which subsequently ratified it as an Internet Standard on 14 July 2017.[3][4]
Devices on the Internet are assigned a unique IP address for identification and location definition. With the rapid growth of the Internet after commercialization in the 1990s, it became evident that far more addresses would be needed to connect devices than the approximately 4 billion (232) addresses IPv4 made available. By 1998, the IETF had formalized the successor protocol, IPv6. It uses 128-bit addresses, yielding an address space of 2128 addresses (approximately 3.4×1038, 340 undecillion). Several transition mechanisms have been devised to allow IPv4 and IPv6 to interoperate, but IPv6 is not backwards-compatible with IPv4 and the two do not interoperate directly.
IPv6 provides other technical benefits in addition to a larger addressing space. In particular, it permits hierarchical address allocation methods that facilitate route aggregation across the Internet, and thus limit the expansion of routing tables. The use of multicast addressing is expanded and simplified, and provides additional optimization for the delivery of services. Device mobility, security, and configuration aspects have been considered in the design of the protocol.
IPv6 addresses are represented as eight groups of four hexadecimal digits each, separated by colons.[5] The full representation must be shortened as much as possible according to specific rules; for example, 2001:0db8:0000:0000:0000:8a2e:0370:7334 becomes 2001:db8::8a2e:370:7334.[6]
Main features
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IPv6 is an Internet Layer protocol for packet-switched internetworking and provides end-to-end datagram transmission across multiple IP networks, closely adhering to the design principles developed in the previous version of the protocol, Internet Protocol Version 4 (IPv4).
In addition to offering more addresses, IPv6 also implements features not present in IPv4. It simplifies aspects of address configuration, network renumbering, and router announcements when changing network connectivity providers. It simplifies packet processing in routers by placing the responsibility for packet fragmentation in the endpoints. The IPv6 subnet size is standardized by fixing the size of the host identifier portion of an address to 64 bits.
The addressing architecture of IPv6 allows three different types of transmission: unicast, anycast and