Limitations of IPv4 and IPv4 exhaustion


How bad is IPv4 address exhaustion?

In September 1981, the fourth version of the IP protocol (IPv4) was described. Then the lack of IP addresses was not even discussed, because the stipulated amount of 4 294 967 294 addresses was considered not just sufficient, but inexhaustible. The IPv4 specification was first published as the IETF RFC 791 standard in 1981. At that time, the Internet was called ARPANET; it had several hundred hosts and was under the control of the US Department of Defense. Things have changed since then, but most of the Internet still uses IPv4.

By 1992, the scalability and limited IPv4 address space became an issue. Changes in the routing architecture and the allocation of address space called CIDR (Classless Inter-Domain Routing), which were standardized in 1993 (RFC 1518, RFC 1518), have significantly slowed down the consumption of addresses.

However, the warning was noted and in early 1994 the IETF began work on creating a new version of the IP protocol, later called IPv6. The base specification was published in 1998 (RFC 2460) and the final version of the IPv6 addressing structure in 2006 (RFC 4291).

Today, the rapid development of the Internet has reached a point where most IPv4 addresses are already distributed. The situation changed by the mid-90s, when CIDR technology was introduced, which allowed blocks of addresses to be allocated according to real needs. At the same time, Regional Internet Registries (RIRs) were formed, responsible for the distribution of addresses and numbers of autonomous networks in accordance with the rules developed by the regional Internet community. The first were RIPE NCC (1992) and APNIC (1993), and then ARIN (1995), LACNIC (2002) and AfriNIC (2005).

After the IPv4 address space ends, the sixth and fourth generation protocols will be used in parallel, with a gradual increase in the proportion of IPv6 traffic compared to IPv4. This situation will be possible due to the presence of a large number of obsolete devices that do not support IPv6 and require special conversion to work with devices that use only IPv6.

What are the limitations of IPv4?

So, here's a list of common IPv4 flaws:

1. The lack of address space - the number of different devices connected to the Internet grows exponentially, and the size of the address space is quickly depleted;

2. Weak protocol extensibility - the insufficient size of the IPv4 header, which does not accommodate the required number of additional parameters;

3. The problem of security of communications - no means are provided to limit access to information hosted on the network. IPv4 has never been designed for security.

  • Originally designed as an isolated military network
  • Then adapted for public education and research network

4. Lack of quality of service support - placement of information about bandwidth, delays required for smooth operation of some network applications are not supported;

5. Geographic limitations - since the Internet was created in the USA, this country is also involved in the distribution of IP addresses. Almost 50% of all addresses are reserved for the United States.

It is impossible to stop the IPv4 depletion and transition to IPv6 is inevitable. Moreover, the growing demand for addresses leads to the appearance of a black market. After the distribution of almost all free addresses, the only way to get addresses will be on the black market and prices will rise significantly. If the survival of your business depends on getting IPv4 addresses, you will be ready to pay for them, even if you must bypass the rules. Fortunately, Carrier Grade Network Address Translation (CGN or CGNAT), also known as Large Scale NAT (LSN) was developed to deal with the IPv4 exhaustion problem and to prevent the appearance of the IP black market. You can find out more about this technology here.
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