Limitations of IPv4 Addresses

When the IPv4 address was invented, it was not expected that the Internet would become so popular that millions of devices would use these IP addresses. The IETF defined IPv4 addresses in RFC 791, published in 1981. The first design of IPv4 did not expect the internet’s growth, which created many issues that proved that IPv4 needed to be changed. Through the years, IPv4 has been updated to address new challenges. However, there are still some major issues, such as a shortage of IPv4 addresses, end-to-end Connectivity, QoS, etc., which we have listed below.


Shortage of IPv4 Addresses

The IPv4 addresses have a 32-bit address space. The 32-bit address space is divided into A, B, C, D, and E classes. These classes have a limited number of unique public IP addresses, about 4 billion. While there is an increasing number of new IP-enabled devices, always-on connections and the potential growth of less-developed regions have increased the need for more addresses, causing a shortage of IPv4 addresses. As the exhaustion and shortage of IPv4 addresses are recognized, engineers have thought of some solutions, which are not permanent but like a workaround to temporary or short-term solutions, such as CIDR, NAT, and private addressing.  We will discuss these solutions in detail in future articles.

Security Related Issues

As I wrote earlier, IP version 4 addresses were published in 1981, and the present network security issues were not expected then. So, Security is another significant aspect where IP version 4 had a pushback. Internet Protocol Security (IP sec) is a protocol suite that enables network security. Internet Protocol Security (IP sec) provides security for IP version 4 packets but is not built-in.

Address configuration-related issues

Networks and the Internet are increasing daily, and many new computers and other devices use IP. The configuration of IP addresses should be simple. We can configure IP version 4 addresses either manually or automatically using DHCP. Nowadays, as almost all devices are IP enabled, we should have more straightforward means to configure rather than have these devices configured automatically without majorly relying on some administration.

Internet routing table expansion

A routing table selects the best path for sending data. As the number of servers connected to the Internet increases, the number of routes also increases. These IP version 4 routes use memory and processor resources on Internet routers.

Lack of end-to-end connectivity

Within the IP version 4 network, NAT is generally used. NAT allows multiple devices to share a single public IP version 4 address. This is difficult for technologies that need end-to-end connectivity because the public IP version 4 address is shared, and the IP version 4 addresses of an internal network host remain hidden.

Quality of service (QoS)

IP version 4 addresses provide Quality of Service (QoS). It relies on the 8-bit TOS field and the identification of the payload. The IP version 4 Type of Service (TOS) field has limited functionality and payload identification.