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IPv4 Exhaustion in Computer Network

  • Last Updated : 09 Mar, 2021

In this, we will discuss the overview of IPv4, it’s format, and will also discuss need of IPv6. And finally will discuss the overview part of IPv6. Let’s discuss it one by one.

Introduction :
Consider that you are sending a letter to your loved one. What would the procedure be? You put an address on the top of the envelope, it gets sorted at the post office and is delivered to the desired location. The transfer of information in the computer world works in quite a similar way. When some information is requested, a set of complex algorithms scan the web and search for the relevant information which is then delivered to the requesting entity. All of this is done under the Internet Protocol (IP), which is a set of rules that governs the flow of packets of information also known as datagrams across the network boundaries.

Overview of IPv4 Exhaustion :

  • From many protocols such as FTP, HTTPS, TCP, and many more, two are IPv4 (Internet Protocol Version 4) and IPv6 (Internet Protocol Version 6).
  • Just like a letter being sent has an address, the data packets being relayed across the networks have an address assigned to them either under the IPv4 or IPv6. Just like you would write an address on the letter you want to be delivered, a central authority called IANA assigns these addresses to Regional Internet Registries (which are responsible for allocation of these addresses in a region of the world) which then assign these addresses to the devices which placed the information request.
  • These addresses have to be unique for each device on a network and these are limited. Imagine what would happen if there are not enough addresses left? You would not be able to request the World Wide Web for the information.

Overview of IPv4 format :  
An IPv4 address has 32 bits, divided into 4 sections of 8 bits each. A typical IPv4 address is of the format as follows.

xxxxxxxx.xxxxxxxx.xxxxxxxx.xxxxxxxx
  • Where each x represents either a 1 or 0. Since it is not easy to remember the binary notation of 32 bits, it is converted into a human-readable decimal form before it is displayed to us e.g. 192.168.4.3.
  • If we try to calculate the number of devices which can be assigned a unique IPv4 address we come to a number that is equal to 232 or 4,294,967,296. Given that an IP address is assigned to every single electronic device capable of accessing the internet, and to every single internet, intranet, and private network, it is not long before the pool of available IP addresses runs dry. 
  • The fact that  Réseaux IP Européens Network Coordination Centre (an RIR that is responsible for the allocation and registration of IP addresses in Europe, Central Asia, Russia, and West Asia) has announced that it has fully run out of IPv4 addresses as of 25 November 2019, shows that it’s a real problem. RIPE NCC is currently scraping IPv4 addresses from the organization that have gone out of business or from networks that return addresses they no longer need and is encouraging the shift from IPv4 to IPv6.
  • Since the development of IPv4 addresses in 1984 by DARPA, it became clear in the first decade that there is a risk of IPv4 addresses running out, also known as IPv4 exhaustion i.e., the number of available IPv4 addresses being less than the number of devices placing requests for information. Attributing to the growth of personal computers and smart devices like speakers, T.V.’s, and watches, we began running out of the available IP addresses more quickly than it was first anticipated.  An alternative had to be looked for.

Need of IPv6 :



  • The Internet Engineering Task Force (IETF) recognized this problem long ago and started working on a solution in the form of a new protocol that would be able to handle the information requests from an increasing number of devices trying to access the internet and could provide a long term solution.
  • IPv6 became the draft standard in 1986 for the Internet Engineering Task Force (IETF). Hence, IPv6 addresses were born. It got formal approval to be declared as an Internet Standard on 14 July 2017.

Overview of IPv6 format :
An IPv6 is a 128-bit address represented in 8 groups of 16 bit each, separated by colon(:) that is as folllows.

xxxxxxxx:xxxxxxxx:xxxxxxxx:xxxxxxxx:xxxxxxxx:xxxxxxxx:xxxxxxxx:xxxxxxxx
  • Where each x is either 1 or 0. These 128 bits are then converted from binary to 8 sets of 4 hexadecimal digits each. Represented as follows.
xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx
  • A typical IPv6 address would look like as follows.
2001:0db8:0000:0000:0000:8a2e:0370:7334
  • As compared to IPv4 which can allot 232 addresses, IPv6 can allot 2128 IP addresses. The exact number we are looking at is 340,282,366,920,938,463,463,374,607,431,768,211,456 supported devices, networks, internets and intranets. The real number of available addresses is however less since some blocks of these addresses are reserved for special purposes.
  • Apart from providing a huge number of available addresses, it has many advantages over IPv4 addresses. IPv6 provides benefits like route aggregation over networks, which limits the expansion of routing tables (a table in a router that stores routes to various routers), minimized packet header processing by routers, multicasting, SLACC, etc.
  • The shift from IPv4 to IPv6 is difficult since these protocols are not interoperable, because of the difference in their headers so direct communication between them is not possible, but the transition from IPv4 to IPv6 is still underway.

References :

  • https://www.arin.net/resources/guide/ipv6/

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