IPv4/IPv6 Transition Mechanisms

The Internet running IPv4 protocol has gained huge success in the past two decades.

The current world is still very predominantly IPv4. However, it has grown to a scale well beyond the designers envisioned over decades ago. In 1998, the Internet Engineering Task Force, IETF, introduced the IPv6 protocol which is designed to overcome the limitation of IP address and security problem. In recent years, a lot of countries in North America, Europe and Asia drive the development of the IPv6 protocol by constructing the IPv6 operational network (Reynders, Wright, 2003, p.

94).Nowadays, more and more people have realized that it is inevitable to transit from IPv4 to IPv6. The IETF believes that the transition from IPv4 to IPv6 is a long-term process and the inter-operation of the IPv4/IPv6 network is also extremely necessary. So the current issue under focus is how to make the IPv4 and IPv6 network inter-operate well enough rather than how to replace the IPv4 network with the IPv6 network. This is also the main reason why the present topic of research was chosen.Background of the researchTransitioning from IPv4 to IPv6 is a very complex problem, which involves the compatibility of the equipments, techniques, applications and so on.

  When IPv6 was designed first, the issue to transitioning was not given much thought. Also, at the time of IPv6 design, internet was still very academic and research oriented and transitioning to v4 to v6 was not a very big logistical issue. The in 1995, the Internet was commercialized and with it the popularity and use of IPv6 exploded (Reynders, Wright, 2003, p. 94).

The rapid uptake of the web during the mid-90s made IPv4 a business critical infrastructure which makes the transition to IPv6 very slow and complicated. A reason for this is because protocol transitions from IPv4 to IPv6 are typically deployed by installing and configuring the new protocol on all nodes within the network and verifying that all node and router operations work successfully. Both the popularity of Internet and complexity of the process are the main reasons why IETF realized that it would be impossible for the entire Internet to switch from IPv4 to IPv6 on a particular day (Reynders, Wright, 2003, p. 95). This realization led to the development of several transition mechanisms to assist in transitioning to IPv6 as defined by the IETF.Purpose of the researchThe IPv6 transition mechanisms ensure that the IPv6 hosts can interoperate with IPv4 hosts anywhere in the Internet up until the time when IPv4 addresses run out, and allows IPv4 and IPv6 hosts within a limited scope to interoperate indefinitely after that.

Hence, the transition of the Internet must meet two separate needs: a short terms need to define the specific technologies and methods to transition IPv4 networks, including the Internet, into IPv6 networks and an IPv6 Internet; and a long term need to do broad-based operational planning for transition-developing strategies and methods for decentralized migration, understanding the ramifications of a long period of coexistence, and developing an understanding of the architectural and interoperability testing that will be required to ensure a reliable and manageable Internet in the future (Shoniregun, 2007, p. 99).This transition from IPv4 to IPv6 has been discussed for years. There is no exclusive or correct mechanism but various organizations have defined and tested multiple methodologies. The purpose of this research paper is to analyze all the transition mechanisms in detail based on their performance.

Statement of the ProblemThis research looks into the various aspects of IPv6 integration and transition with existing IPv4 networks. While the process can be complex and difficult, when planned well with the right protocol chosen, the deployment can be effective. Transition mechanisms are so called because they are ostensibly ways in which the present networks can be moved to IPv6. In reality IPv4 and IPv6 are likely to be cooperating on most networks for a long while, so they might better be called inter-operating techniques (Goswami, 2003, p. 46). In any case, there are quite a few transition mechanisms and they have a wide variety of capabilities.

To handle the issue of IPv6 transition, IETF has started a working group called NGTRANS to oversee standard ways of transitioning (Goswami, 2003, p. 47). The 6bone was the first IPv6 test bed that is a worldwide informal collaborative project. The transitioning mechanisms and procedures are mainly of three types:o Dual IP layero IPv6 over IP v4 tunneling mechanisms such as IPv6-in-IPv4 tunneling, tunnel brokers, ISATAP, 6to4, Teredoo Translation mechanisms such as NAT-PT, SIIT, SOCKS, ALGs, and Bump-in-the-stack/API.When IPv6 is introduced in the IPv4 based Internet, a plethora of inter-working issues will arise, including but not limited to routing, addressing, and Domain Naming System, DNS.

Another important key to a successful IP transition is compatibility with the large installed base of IPv4 hosts and routers. Customers at all levels will expect seamless inter-working. These inter-working issues apply to all types of IP-based networks including VoIP networks (Goswami, 2003, p. 48).Although these are many non-technical issues involved in the transition from and IPv4 only world to one in which IPv6 is an important protocol, technical issues must be resolved first before taking up the task of implementing and deploying IPv6.When introducing IPv6 in the Internet there are two sets of problems.

The first one is related to having IPv6 communications among two or more isolated IPv6 islands in the IPv4 network. The second is related to the establishment of communications between the existing IPv4 and the new IPv6 networks (Minoli, 2006, p. 323). The performance of transition mechanisms need to be evaluated on this aspect.

The transition mechanisms given above are intended to a part of a transition tool box, which may be used as need. Implementations and sites decide which techniques are appropriate to their specific needs. RFC defines the initial core set of transition mechanisms, but these are not expected to be the only tools available (Minoli, 2006, p. 324).

Additional transition and compatibility mechanisms are expected to be developed in the future with new IETF RFCs and documentation being written to specify them In addition, the transition scenarios as proposed in IETF working groups have largely being theoretical in nature and reflect proposed solutions more than reality. The exact analysis of the transition mechanisms in a common set of scenarios has not yet been undertaken which is the most important aspect.