Saturday, February 21, 2009

Some thoughts about IPv6

I read an article at IANA about the current state of IPv6 implementation on the world wide internet. I just thought of sharing few points here, as mentioned in the IANA IPv6 report, to help spread some awareness about this important issue. The article presents following facts:

1. IPv4 (the current traditional sceme of IP address allocation) theoretically has address space of about 4-5 billion IP addresses. When this scheme was designed, when the modern internet came into existence, it was imagined that about 4-5 billion devices will be a good maximum limit to the number of devices which can be connected to the internet.

But with the growing popularity of the internet across the world, the IPv4 scheme has proved to be insufficient to scale the internet using new devices. By Oct 2007, only 17% IP addresses were available for allocation under IPv4 scheme. Somewhere in 2010-11, all the IPv4 addresses will be exhausted. So after that time, it will be inevitable for the world to shift to IPv6 scheme to add more IP devices to the internet.

Apart from computer machines needing to connect to internet, many different kind of devices are now being designed to have IP capability (like many home appliances for example). To be able to assign all these new devices the globally unique IP addresses, adoption of IPv6 is bound to take place.

2. During the transition period from IPv4 to IPv6, both IPv4 and IPv6 hosts can continue to coexist and interoperate. But interoperation of these two schemes would require investment of time and money from hardware vendors, and network service providers.
The IPv4 scheme is expected to continue in operation for couple of years from now (I guess 5-10 years).

3. The IPv6 support in the softwares seems not to be a problem. Major OS vendors already have IPv6 support built into the OSs. The challenging aspect is the IPv6 support from the hardware and network equipment providers. I am sure that hardware and network vendors who intend to be be in the internet business for a long time in future, will commit the time and money to bring this vital expansion of the internet.

Interestingly, JDK 1.4 and above has provided support for IPv6 based IP addresses. So writing IPv6 enabled client applications is already possible with Java JDK.

Google is also serious about IPv6 adoption. The google search service is now available for IPv6 enabled devices. Please refer, for more information about Google's efforts to promote IPv6 scheme. is the web URL to do google search from IPv6 machines. If you do a google search from an IPv4 machine (as I do, from the IP address to this host, you'll get an "unknown host error". The machine should have an IPv6 based IP address to access this search service from Google.

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