Tuesday, January 25, 2011

IPv4 will be used up really soon. Are we ready for IPv6?

The IP address in the format of XXX.XXX.XXX.XXX (i.e. IPv4) which is the basic identification of every device connected to the Internet is predicted to be fully allocated (used up) on the estimated date of 2 February 2011. Take a look at the ticking counter of IPv4 exhaustion here.

The current IPv4 address space is a 32 bit field, possible for 4,294,967,296 (4.29 billion) allocations. It is used by all network devices connected using the TCP/IP protocol, including computers, mobile devices, network devices, certain telecommunication devices, certain electrical appliances, and everything connected to the Internet with TCP/IP.

IPv4 started around 1980. By that time, only a handfull of computers, mostly in military and academic institutions (i.e. universities) are connected to the Internet and linked up with TCP/IP. The allocation of IPv4 accelerated in the 1990's when the whole world are connected to the Internet. Its exhaustion rate spurred further in the 2000's when not only computers and network devices are connected to the Internet, but also many other electrical and electronic devices, especially the mobile phones.

As a result, now we are very close to the end. All the 4.29 billion IP addresses will be fully used, and will not be sufficient for every devices that need to connect to the Internet anymore.

Various measures have been taken to slow down the exhaustion, such as special allocation for private IP address blocks (10.x.x.x, 192.168.x.x, and 172.16.x.x – 172.31.x.x) so that devices not directly connected to the Internet can make use of these private IP addresses, and they can share a same Internet IP address with NAT translation at the gateway/router.

The exhaustion of IPv4 has already taken into account for these kind of measures. It should have come even earlier if without private IP address and NAT in place nowadays.

In fact, the Internet authorities have thought about this issue long time ago, and have planned for the migration to the next generation of IP address system, namely IPv6. In fact, one of my project assignment during university studies in mid-1990's is about IPv6. Therefore, you should know that the research on IPv6 has been around for more than 10 years.

IPv6 uses a 128-bit address, whereas IPv4 uses only 32 bits. The new address space supports unlimited address allocation (3.4 x 10^38). With this much amount of IP addresses available, it also eliminates the need for NAT, and every devices can have their Internet IP address, just like the scenario for IPv4 before the introduction of NAT.

The IPv6 format will look like this: XXXX:XXXX:XXXX:XXXX:YYYY:YYYY:YYYY:YYYY, where the first 4 groups (XXXX part) is a 64-bit network prefix, and the last 4 groups (YYYY part) is a 64-bit host address. All the digits are in hexadecimal.

It is reported that big Internet players including Google, Facebook, Yahoo, Akamai, Limelight Networks, etc. will have a 24-hour test run on IPv6 during the World IPv6 Day on 8 June 2011. Click here to read more about World IPv6 Day.

We have to move on. Are we ready for IPv6? (Especially service providers, device manufacturers, software developers, network engineers, ...)


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