Limitations of IPv4
The Internet Protocol Version 4 (IPv4) is defined by IETF RFC 791. RFC 791 was initially published in 1981. Initial design of IPv4 did not anticipate the growth of internet and this created many issues, which proved IPv4 need to be changed.
The main limitations of IPv4 are listed below.
• Scarcity of IPv4 Addresses: The IPv4 addressing system uses 32-bit address space. This 32-bit address space is further classified to usable A, B, and C classes. 32-bit address space allows for 4,294,967,296 IPv4 addresses, but the previous and current IPv4 address allocation practices limit the number of available public IPv4 addresses. Many IPv4 addresses allocated to organizations as bulk, were not used. This created scarcity of IPv4 addresses.
Because of the scarcity of IPv4 addresses, many organizations implemented NAT (Network Address Translation) to map multiple private IPv4 addresses to a single public IPv4 address. By using NAT (Network Address Translation), we can map many internal private IPV4 addresses to a public IPv4 address, which helped in conserving IPv4 addresses. But NAT (Network Address Translation) also had many limitations. NAT (Network Address Translation) did not support network layer security standards and it did not support the mapping of all upper layer protocols. NAT also created network problems when two organizations used the same private IPv4 address ranges to communicate. More servers, workstations and devices which are connected to the internet also demanded the need for more addresses and the statistics proved that the available public IPv4 addresses will be depleted soon or later.
The scarcity of IPv4 addresses was a major limitation of IPv4 addressing system.
• Security Related Issues: As we discussed before, RFC 791 (IPv4) was published in 1981 and the current network security threats were not anticipated at that time. Internet Protocol Security (IPSec) is a protocol suite which enables network security by protecting the data being sent from being viewed or modified by a third-party person. Internet Protocol Security (IPSec) provides security for IPv4 packets, but Internet Protocol Security (IPSec) is not built-in and optional in Internet Protocol Version 4 (IPv4). Many IPSec implementations used in Internet Protocol Version 4 (IPv4) are proprietary.
• Address configuration related issues: Networks and also internet is expanding and many new computers and devices are using Internet Protocol. The configuration of IP addresses (static or dynamic) should be simple.
• Quality of service (QoS): Quality of Service (QoS) is available in IPv4 and it relies on the 8 bits of the IPv4 Type of Service (TOS) field and the identification of the payload. IPv4 Type of Service (TOS) field has limited functionality and payload identification (uses a TCP or UDP port) is not possible when the IPv4 datagram packet payload is encrypted.
Written by Jajish Thomas. Last updated on 14th May, 2024.