In practice, built-in mobile browsers use IPv4 since IPv6 was not yet popular.

However, due to the enormous growth of the Internet and the predicted depletion of available addresses, a new version of IP ( IPv6 ), using 128 bits for the address, was developed in 1995.

The gap in version sequence between IPv4 and IPv6 resulted from the assignment of number 5 to the experimental Internet Stream Protocol in 1979, which however was never referred to as IPv5.

IPv6 was developed by the Internet Engineering Task Force ( IETF ) to deal with the long-anticipated problem of IPv4 running out of addresses.

By 1996, a series of RFCs was released defining Internet Protocol version 6 ( IPv6 ), starting with RFC 1883.

APNIC was the first RIR to exhaust its regional pool on 15 April 2011, except for a small amount of address space reserved for the transition to IPv6, which will be allocated in a much more restricted way.

Internet Protocol Security ( IPsec ) was originally developed for IPv6, but found widespread deployment first in IPv4, into which it was back-engineered.

Earlier, IPsec was an integral part of the base IPv6 protocol suite, but has since been made optional.

To operate with IPv6 networks, the OSPF protocol was rewritten in OSPF v3 ( as specificed in RFC 2740 ).

Global Crossing was the first global communications provider with IPv6 natively deployed in both its private and public backbone networks.

* IPSec ( Internet Protocol Security ) was developed by the Internet Engineering Task Force ( IETF ), and was initially developed for IPv6, which requires it.

* The AM-NIC was moved over to IPv6 address compatibility in line with the global DNS system.

Most recently, the specification was revised to significantly increase transmission speeds ( this time both upstream and downstream ) and introduce support for Internet Protocol version 6 ( IPv6 ).

The only remaining technical role of < tt > int </ tt > was for reverse translation of IPv6 addresses under the < tt > ip6. int </ tt > zone.

The IPv6 stack was contributed by Cisco and was at the time of release, the smallest IPv6 stack to receive the IPv6 Ready certification.

IPv6 was enabled at the transport layer to TLD nameservers a few years prior to that.

The Spamhaus White List ( SWL ) was released in October 2010 and is a whitelist of IPv4 and IPv6 addresses.

The IPv6 subnet size has been standardized by fixing the size of the host identifier portion of an address to 64 bits to facilitate an automatic mechanism for forming the host identifier from link-layer media addressing information ( MAC address ).

Multihoming in the next-generation Internet Protocol ( IPv6 ) is not yet () standardized, as discussions about the various possible approaches to multihoming are still unresolved.

Version numbers 6 through 9 were proposed for various protocol models designed to replace IPv4: SIPP ( Simple Internet Protocol Plus, known now as IPv6 ), TP / IX ( RFC 1475 ), PIP ( RFC 1621 ) and TUBA ( TCP and UDP with Bigger Addresses, RFC 1347 ).

The main QoS-related IETF Request For Comments ( RFC ) s are Definition of the Differentiated Services Field ( DS Field ) in the IPv4 and IPv6 Headers ( RFC 2474 ), and Resource ReSerVation Protocol ( RSVP ) ( RFC 2205 ); both these are discussed above.

The updates for IPv6 are specified as OSPF Version 3 in RFC 5340 ( 2008 ).

OSPF reserves the multicast addresses < tt > 224. 0. 0. 5 </ tt > for IPv4 or < tt > FF02 :: 5 </ tt > for IPv6 ( all SPF / link state routers, also known as < tt > AllSPFRouters </ tt >) and < tt > 224. 0. 0. 6 </ tt > for IPv4 or < tt > FF02 :: 6 </ tt > for IPv6 ( all Designated Routers, < tt > AllDRouters </ tt >), as specified in RFC 2328 and RFC 5340.

RIPng ( RIP next generation ), defined in RFC 2080, is an extension of RIPv2 for support of IPv6, the next generation Internet Protocol.

Later, in RFC 6214 released on 1 April 2011, and 13 years after the introduction of IPv6, Carpenter and Hinden published Adaptation of RFC 1149 for IPv6.

IPv6 designates only a single address for this function, 0: 0: 0: 0: 0: 0: 0: 1 ( also written as :: 1 ), having the :: 1 / 128 prefix ( RFC 3513 ).

* RFC 2474 — Definition of the Differentiated Services Field ( DS Field ) in the IPv4 and IPv6 Headers

* The IPv6 Technical Preview for Windows 2000 ( December 2000 ) saw the first implementation of RFC 2553 ( March 1999, later obsoleted by RFC 3493 ), a protocol-independent API for name resolution, which would become part of Winsock in Windows XP.

* RFC 3089: A SOCKS-based IPv6 / IPv4 Gateway Mechanism

For link-local addressing IPv4 uses the special block < tt > 169. 254. 0. 0 / 16 </ tt > as described in RFC 3927 while IPv6 hosts use the prefix < tt > fe80 ::/ 10 </ tt >.

Both modes were updated in September 1998 to support IPv6.

Decomposition of an IPv6 address into its binary form

The main advantage of IPv6 over IPv4 is its larger address space.

UDP / IPv4 may actually have a checksum of 0, indicating no checksum ; IPv6 requires UDP to have its own checksum.

Compared to IPv4, the most obvious advantage of IPv6 is its larger address space.

The most common network addressing architecture is Internet Protocol version 4 ( IPv4 ), but its successor, IPv6, is in early deployment stages.

* In IPv6, < tt > 2001: db8 ::/ 32 </ tt > designates the address < tt > 2001: db8 ::</ tt > and its network prefix consisting of the most significant 32 bits.

Thus, when an IP packet reaches its destination ( sub ) network, the destination IP address ( a layer 3 or network layer concept ) is resolved with the Address Resolution Protocol for IPv4, or by Neighbor Discovery Protocol ( IPv6 ) into the MAC address ( a layer 2 concept ) of the destination host.

In IPv6, on the other hand, the loopback routing prefix < tt >:: 1 / 128 </ tt > consists of only one address < tt >:: 1 </ tt > (< tt > 0: 0: 0: 0: 0: 0: 0: 1 </ tt > in full notation, the address with a one at its least significant bit and zero otherwise ) is explicitly defined as the loopback address, though additional addresses may be assigned as needed to the loopback interface by the host administrator.

To allow a 6to4 host to communicate with the native IPv6 Internet, it must have its IPv6 default gateway set to a 6to4 address which contains the IPv4 address of a 6to4 relay router.

When a site using 6to4 has a fixed global IPv4 address, its 6to4 IPv6 prefix is also fixed.

* if the source IPv6 address is a 6to4 IPv6 address, its corresponding 6to4 router IPv4 address matches the IPv4 source address in the IPv4 encapsulation header,

* similarly, if the destination IPv6 address is a 6to4 IPv6 address, its corresponding 6to4 router IPv4 address matches the IPv4 destination address in the IPv4 encapsulation header,

The IPv6 defragmenter is not a module in its own right, but is integrated into the nf_conntrack_ipv6 module.

Additionally, a performance comparison between Mobile IPv6 and some of its proposed enhancements ( Hierarchical Mobile IPv6, Fast Handovers for Mobile IPv6 and their Combination ) is available at.

Just days prior to the World IPv6 day, DK Hostmaster added an IPv6 address to their web server and that of its owner, DIFO.

A computer with a host-specific relay will use Teredo to communicate with Teredo clients, but it will stick to its main IPv6 connectivity provider to reach the rest of the IPv6 Internet.