When the IPv4 protocol of assigning host addresses was introduced, nobody would have imagined that there would be 4 billion devices connected across a large- scale network. That was back in the 70s and before the age of the Internet.
In time, it became clear that more addresses would be needed and in 1999 the IPv6 was proposed. The IPv6 was introduced to overcome the IP address space shortage in addition to providing other benefits.
IPv4 is a 32-bit address protocol while IPv6 is a 128-bit protocol. A 32-bit address space implemented using IPv4 allows for 4, 294, 967, 296 possible addresses. That is slightly above 4 billion addresses. A 128-bit address space on the other hand implemented using IPv6 would have 3.4 x 1038 possible addresses. It is hard to conceive if all these P addresses will ever be consumed. Well, consider this, with IPv6 there are 6.65 x 1023 addresses for every square meter on Earth.
Looking closely at the syntax of these 2 protocols, IPv4 are delineated in dotted-decimal formats separated along 8-bit boundaries. IPv6 however is divided along 16-bit boundaries. IPv4 is represented in 4 blocks of 8-bit binary while IPv6 is in groups of 16-bit hexa values separated by colons.
Another notable difference is that IPv6 supports a bigger payload than IPv4. This difference can be seen in the header information contained in the IPv6 packets. The packet headers define the payload length, hop limit, source and destination address all of which affect the payload. While many of the fields found in IPv4 packet headers are still found in IPv6, there is a slight difference in the information or naming of the fields.
At the moment, IP tunneling is employed to allow IPv4 and IPv6 interconnection and make it possible to run both address types. In addition, most devices and networks that have IPv6 support also support for IPv4 addresses.
2 Comments
Trying to tout ipv6 as some kind of panacea is irresponsible. As you yourself noted, no one thought the 4 billion+ addresses under ipv4 would ever be needed. Well guess what: the rise of the web proved *that* wrong pretty damn quickly.
Now you’re saying ipv6 will see us okay for ages. But the upsurge in the number of mobile devices all needing their own ip will bite a huge chunk out of it right away. And then there’s the hitherto-unknown advances in tech. There are going to be all sorts of stuff coming round the corner, all of which will put the web to shame. Those technologies will demand ip addresses far above and beyond what the web did to ipv4. None of us can truly see the future – but I’m willing to bet that ipv6 will run out, just like ipv4, well ahead of its projected “life span”.
Hi Bob,
It will take a dramatic increase in population and over-dependency on gadgets that are always connected online to exhaust IPv6 addresses. There are roughly 340 undecillion IPv6 addresses available for use. We cannot possibly exhaust all these in the near future. If it happens, IPv7 is already being considered.