When IPv4 address was invented, it was not expected that the usage of the Internet would become; so popular and it would have millions of devices using these IP addresses. The IETF defined IPv4 addresses in RFC 791 published in 1981. The first design of IPv4 does not expect the growth of the internet; and this created many issues, which proved IPv4 need to be changed. Through the years, IPv4 has updated to address new challenges. However, still, some major issues like shortage of IPv4 Address, End to End Connectivity, QoS, etc which we listed below.
Shortage of IPv4 Addresses
The IPv4 addresses have a 32-bit address space. The 32-bit address space is further divided into A, B, C, D and E classes. These classes have a limited number of unique public IP addresses which is about 4 billion. While there is, the 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 cause a shortage of IPv4 addresses. As the exhaustion and shortage of IPv4 addresses recognized, engineers thoughts some solutions; which are not permanent but like a workaround to temporary or short term solutions is CIDR, NAT, and Private Addressing. We will discuss these solutions in details in coming articles.
Security Related Issues
As I write earlier that IP version 4 addresses were published in 1981 and the present network security issues were not expected at that time. So Security is another big aspect where IP version 4 had a push back. Internet Protocol Security (IP sec) is a protocol suite which enables network security. Internet Protocol Security (IP sec) provides security for IP version 4 packets, but it is not built-in.
Address configuration related issues
Networks and the internet are increasing day by day and many new computers and other devices are using IP. The configuration of IP addresses should be simple. We can configure IP version 4 address either configured manually or automatically using the DHCP. Nowadays days as almost all devices are IP enabled; we should have simpler means to configure rather 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. Because of the number of servers connected to the Internet increases, which also increase the number of a route. 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 makes possible to give a way for 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 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 bits TOS field and the identification of the payload. IP version 4 Type of Service (TOS) field has limited functionality and payload identification.