The current version of the Internet Protocol IPv4 was first developed in the 1970s, and the main protocol standardHistory of IPv6 RFC 791 that governs IPv4 functionality was published in 1981.

With the unprecedented expansion of Internet usage in recent years – especially by population dense countries like India and China. IPv6

The impending shortage of address space (availability) was recognized by 1992 as a serious limiting factor to the continued usage of the Internet run on IPv4.IPv6 Evolution

The following table shows a statistic showing how quickly the address space has been getting consumed over the years after 1981, when IPv4 protocol was published

address space getting consumed

With admirable foresight, the Internet Engineering Task Force (IETF) initiated as early as in 1994, the design and development of a suite of protocols and standards now known as Internet Protocol Version 6 (IPv6), as a worthy tool to phase out and supplant IPv4 over the coming years. There is an explosion of sorts in the number and range of IP capable devices that are being released in the market and the usage of these by an increasingly tech savvy global population. The new protocol aims to effectively support the ever-expanding Internet usage and functionality, and also address security concerns.

IPv6 uses a128-bit address size compared with the 32-bit system used in IPv4 and will allow for as many as 3.4×1038 possible addresses, enough to cover every inhabitant on planet earth several times over. The 128-bit system also provides for multiple levels of hierarchy and flexibility in hierarchical addressing and routing, a feature that is found wanting on the IPv4-based Internet.

A brief recap of the major events in the development of the new protocol is given below:

  • Basic protocol (RFC 2460) published in 1998
  • Basic socket API (RFC 2553) and DHCPv6 (RFC 3315) published in 2003.
  • Mobile IPv6 (RFC 3775) published in 2004
  • Flow label specifications (RFC 3697) added 2004
  • Address architecture (RFC 4291) stable, minor revision in 2006
  • Node requirements (RFC 4294) published 2006

IPv6 Features

The massive proliferation of devices, need for newer and more demanding applications on a global level and the increasing role of networks in the way business is conducted are some of the pressing issues the IPv6 protocol seeks to cater to. The following are the features of the IPv6 protocol:

  • New header format designed to keep header overhead to a minimum – achieved by moving both non-essential fields and optional fields to extension headers that are placed after the IPv6 header. The streamlined IPv6 header is more efficiently processed at intermediate routers.
  • Large address space – IPv6 has 128-bit (16-byte) source and destination IP addresses. The large address space of IPv6 has been designed to allow for multiple levels of subnetting and address allocation from the Internet backbone to the individual subnets within an organization. Obviates the need for address-conservation techniques such as the deployment of NATs.
  • Efficient and hierarchical addressing and routing infrastructure- based on the common occurrence of multiple levels of Internet service providers.
  • Stateless and stateful address configuration both in the absence or presence of a DHCP server. Hosts on a link automatically configure themselves with link-local addresses and communicate without manual configuration.
  • Built-in security: Compliance with IPSec [10] is mandatory in IPv6, and IPSec is actually a part of the IPv6 protocol. IPv6 provides header extensions that ease the implementation of encryption, authentication, and Virtual Private Networks (VPNs). IPSec functionality is basically identical in IPv6 and IPv4, but one benefit of IPv6 is that IPSec can be utilized along the entire route, from source to destination.
  • Better support for prioritized delivery thanks to the Flow Label field in the IPv6 header
  • New protocol for neighboring node interaction- The Neighbor Discovery protocol for IPv6 replaces the broadcast-based Address Resolution Protocol (ARP), ICMPv4 Router Discovery, and ICMPv4 Redirect messages with efficient multicast and unicast Neighbor Discovery messages.
  • Extensibility- IPv6 can easily be extended for new features by adding extension headers after the IPv6 header.

IPv6 thus holds out the promise of achieving end-to-end security, mobile communications, quality of service (QoS), and simplified system management.

RFC Links

Communication between computers on the Internet is made possible through the exchange of packets of digitalRFC Links information in a system dictated by Internet Protocols. The specifications for standard Internet Protocols are recorded in the form of a Request For Comments (RFC) document.

There exist eight higher level protocols above the Internet Protocol, which provide additional functionality to different applications. The nine fundamental Internet protocols are referred to by their own acronyms, and are described by the respective RFC’s:

history of IPv6 protocol

IPv6 has a number of technical features making it feasible to support a range of next-generation network applications and services. It is also equipped with extension headers that will make it easy to integrate future features and services without having to rewrite the protocol. Some of the important standards for specification of these features and functionality are given below:

RFC 2460 – Internet Protocol Version 6 (IPv6) Specification. This standard covers the following:

128-bit Addressing: Scalability from 232 potential addresses to 2128 addresses, vastly
expanding usable unicast and multicast address space

End-to-End Addressing: Reintroduces the end-to-end model to greatly lower the cost and complexity of peer-to-peer communications by eliminating the need for Network Address Translation (NAT)

Improved QOS Support: More QOS options with flow labels and extension headers

Simplified Header: Improved header structure sSpeeds up packet processing in routers and
makes basic IPv6 header more compressible (than IPv4) for low data rate wireless and dial-up connections.

Extensible Headers: Allows additional protocol-level information to be added to the basic IPv6 header so IPsec and mobile IPv6 are easily integrated on top of the basic IPv6 protocol

Advanced Network Services: Basic Ipv6 features and extension headers can be leveraged to
build more powerful network services for mobility, security, QOS, peer-to-peer applications, etc.

RFC 2460, 4301, & others
Improved security support via IP layer security (IPsec) making it cheaper to deploy VPN-like security for all applications

RFC 2461, 2462 & others
Autoconfiguration: Improved plug and play support using IPv6 link-local addressing, scoped multicasting & anycast support to automatically self-configure and discover neighbor nodes, routers, and servers

RFC 2463
Internet Control Message Protocol for IPv6 (ICMPv6)

RFC 4291, 4193
New Address Types: New addressing options for link local, anycast, intra-domain3, and globally unique Internet communications.

RFC 3041, 3972
Security Addressing: New security addressing options for randomly generated addresses to protect privacy and cryptographically generated addresses used to sign and authenticate messages.

RFC 2460, 3306, 4291
Enhanced Multicast Features: Enhanced local and global multicasting support scoped multicasting, and tremendous expansion of usable multicast address space.

RFC 4291
Multi-homing Features: Multiple addresses can be assigned to IPv6 network interfaces. Use of different addresses can be used to differentiate link-local, intra-domain, and global messages.


IPv6 deployment is gaining speed as IPv6 infrastructure is being installed throughout the Internet backbone and the major wide-area networks. Tier-1 Internet backbone networks run by AOL Transit Data Network, AT&T, Global IPv6 TimelineCrossing, Level 3, MCI, NTT (Verio), Sprint Nextel, Qwest, SAVVIS, VSNL-Teleglobe, Telesonera, France Telecom, Telefonica have already tested and deployed using IPv6.

The major wide-area R&D networks that have been in operation with IPv6 infrastructure, services, and applications for some time now are: AARNET (in Australia), Abilene (Internet2 – in the US), ERNET (in India), CSTNet2 & CERNET2 (in China), Gigabit European Academic Network (GEANT) (in Europe), JGN2 & WIDE (in Japan), KREONET2 (in Korea), RedCLARA (in Latin America), RUNet & FREEnet (in Russia), and TANET2 & TWAREN (in Taiwan).

Projected IPv6 Timeline

Projected IPv6 Timeline

Adapted from Source: IPv6 Timeline A pragmatic projection

A joint project between Lumeta Inc. and the IPv6 Forum (world-wide consortium of leading Internet vendors, industry subject matter experts, and research & education networks formed with the mission to drive IPv6 deployment) was taken up during 2005 to study IPv6 deployment at the global level.

The findings indicate that the IPv6 core is well supported, has proven interoperability, is being deployed in the latest generation of routers and operating systems, and is being extended to the last-mile infrastructure necessary to support complete enterprise transitions.

Additional standards for stateful autoconfiguration (DHCPv6), IPsec key exchange (IKEv2), SEcure Neighbor Discovery (SEND), and IPv6 over emerging link layers (802.15, WiMAX, etc) are being tested and deployed in new IT infrastructure. The integration of IPv6 into enterprise applications, network management, and security infrastructure is already in progress by governmental initiatives in Asia and the U.S.

The U.S. Government, for one, has issued a mandate that the network backbones of all federal agencies must deploy IPv6 by 2008. As things stand, the IPv6 Forum projects the worldwide Internet penetration to reach 25% by 2010, 35% by 2015 and 50% by 2020. By the year 2010, according to the IPv6 Forum, “IPv6 will become a dominant protocol and the New Internet will become commodity for everyone and everything.”