The widespread adoption of Internet Protocol version 6 or IPv6 critically depends upon its interoperability with the existing protocols prominent among them being the Internet Protocol version 4 or the IPv4 that was the predecessorinteroperability technology protocol to the IPv6 standard.

An improved interoperability allows the market players to undertake a smooth transition from one standard to another without having to face any significant hiccups or disruptions to the service. IPv6

Any change from one protocol to the other needs resources, both in terms of the money as well as the time that it takes for the processes to attune to the new ways of doing things.

Any such disruption to the routine activities significantly impairs the normal operation of processes running on those protocols. In such cases, interoperability offers the much-needed respite as it saves the organizations from any disruption to their routine operations.

It also allows adoption of the new protocol in phases so that the potential for disruption or a general risk to the process is minimized and the operations can continue in a smooth fashion. This way, interoperability allows the transition to a new standard, technology, or protocol in a seamless manner. This tends to make interoperability a sought after quality for any new technology.

At present, IPv4 still dominates majority of the Internet traffic. However, IPv6 is making slow but steady inroads. Ever since the support extended by the Internet Corporation for Assigned Names and Numbers (ICANN) to the IPv6 protocol by modifying the DNS root servers on July 20th, 2004, the IPv6 adoption has seen an exponential growth. The IPv6 development was stimulated due to exhaustion of addressing space offered by Pv4 to accommodate all the nodes on the Internet.

A complete replacement of IPv4 by IPv6 will take quite some time. Till then, a number of transition mechanisms allow IPv6-only compatible hosts to access services offered by IPv4 protocol. This forms the backbone of theinteroperability mechanism interoperability ingrained in the IPv6 protocol.

These transition mechanisms allow IPv6-only compatible machines to utilize the various services offered by the IPv4 compatible resources over the Internet. Hence, the transition mechanisms were detrimental in a widespread adoption of the IPv6 protocol.

Recognizing the importance of IPv6 interoperability with the existing IT infrastructure, a number of prominent research groups around the world are conducting studies to test the interoperability parameters of the new protocol both at the hardware and the software levels. At the hardware level, it pertains to testing the performance of different system configuration in an IPv6 framework while the software level testing involves an assessment of the coordination of various applications at different levels of protocol transition process. The interoperability tests include firewalls, voice, wireless and application layer interface testing. The tests include interoperability in pure IPv6 configurations as well as a mix of IPv6 and IPv4 over IEEE 802.11, VoIP, IPsec, wireless LANs, DNS, DHCP and the different application platforms.

Some of the prominent research groups involved in the IPv6 interoperability testing include:

1.UNH-IOL The University of New Hampshire IPv6 Interoperability laboratory. The UNH-IOL is at the forefront of the IPv6 interoperability testing initiative. It collaborates with a number of other research groups to undertake research and testing activities.

2.The Moonv6 project A collaboration between NAv6TF (North American IPv6 Task Force), UNH-IOL and the allied government agencies. The collaboration is aimed at testing the broad spectrum of potential usage of IPv6 over an increasingly networked technology domain.

3.DoD (JITC) The US Department of Defense, Joint Interoperability Test Command. The JITC offers a platform for the various research groups to share their knowledge and the work being carried out towards the promotion of improved network protocols such as the IPv6 that are finding increasing usage in diverse applications.

4.TAHI project This is a Japanese research group comprising of the University of Tokyo and Yokogawa Electric Corporation. The project began on Oct 1, 1998 and is aimed at providing superior networking solutions by stimulating the development and subsequent adoption of the Pv6 standard over the Internet.

5.KAME project It is a research group comprising of six Japanese companies working to explore free stack for IPv6 and mobile IPv6 for BSD variants. The research aims to promote the adoption of the IPv6 protocol.

6.USAGI project The UniverSAl playGround for Ipv6 project aims to offer IPv6 and IPsec (for IPv4 and IPv6) protocol stack for Linux based open source platforms. This project has a voluntary membership and derives experts from various organizations. This project is a Japanese initiative open to experts from all over the world to promote IPv6 protocol over an open platform such as Linux.

We are witnessing a broad spectrum of potential usage for IPv6 over an increasingly networked technology domain. In the future, Information networks will form the backbone of the IT domain and network protocols such as the IPv6 will in turn act as a backbone to the Information networks. The interoperability issues in IPv6 are critical in this age of convergence where different technologies running on diverse platforms will need to communicate via protocols such as the IPv6.