When IP Addresses Get Over

With the advent if IoT, the number of devices that need to connect to the internet is increasing every day. When a device connects to the internet, it is assigned a specific IP address. This address is unique to each device. The system widely in use today, the Internet Protocol Version 4 (IPv4), uses a 32bit number for the address. The 32 bits mean that the number of available addresses is 2^32 (4,294,967,296). But, the number of connected devices is increasing today at an average rate of 5.44 billion per year. This means that the number of available addresses will soon get exhausted! Does that mean the end of the internet and a promising technology like the IoT?

Definitely not! Internet Protocol Version 6 (IPv6) is your knight in the shining armour. IPv6 will prevent the annihilation of the internet! The IPv6 redesigns the internet protocol itself. First major change is the number of addressing bits. It uses 128 bits instead of 64 (giving us around 3.403×10³⁸ addresses).

But what exactly is IP? The full form is obviously well known, but what is the necessity of IP in using the internet? The internet consists of 4 layers. At the top, is the application layer. This has the applications you use every day like Facebook, Whatsapp and such. Next is the transport layer. TCP is a popular transport layer and it’s implemented along with the IP layer. The third is the network layer, which is the Internet Protocol. The last one, the link layer can be Ethernet or WiFi. The network encapsulates the data into packets called datagrams. A datagram has data and a header. The header has a fixed structure and so some specific duties to perform. So, when I said IPv6 redesigns the internet protocol, I meant that the header is changed. The rest of the datagram is the payload or the data.

IPv4 has a fixed payload length field of 16 bits in the header. This gives us the ability to specify 65535 octets or bytes. But in IPv6, we can use a jumbogram which allows us to specify payload sizes of up to one byte less than 4 GB. Further, in this new version of IP, has network layer security. Normally, the network layer just forwards the packets along the network on a hop by hop basis. But the Internet Protocol Security (IPSec) is a mandatory specification for IPv6. For IPv4, it was optional. The packet header and the process of forwarding have also been simplified, although the headers in v6 are longer.

These are the differences. So how do we go about changing over from IPv4 to IPv6? The Internet Engineering Task Force (IETF) has recommended certain deployment models and migration tools for the transition. Temporary goals of the transition are to enable parts of the internet to employ IPv6 and disable v4. The end goal is a network-wide IPv6 deployment which will result in IPv4 becoming obsolete. The simplest model is to use a dual stack and allow both the versions to run simultaneously. In such a network, it is up to the peers connected to each other to decide which version to use. But, the peers should be reachable by an IPv6 address and should advertise their using a naming service like DNS. This is the recommended approach wherein IPv4 can then be phased out once all peers on the network have an IPv6 address. Other approaches include tunnelling through IPv4 networks and creating IPv6 only networks.

The government of India too, has created its own deployment model in accordance with the e-governance plan. Thus, IPv6 is about to kill IPv4 and open up a whole new world to us.

Sources: www.statistica.com; Wikipedia; Stanford Lagunita, Introduction to Computer Networks course; docs.oracle.com, IPv6 administration guide; tools.ietf.org, Guidelines for using IPv6 Transition Mechanisms;