[Darmi Jillo]

IPv4 has lasted this long due to its widespread early adoption and the implementation of techniques like NAT (Network Address Translation), CIDR (Classless Inter-Domain Routing) & VLSM to extend its usability. However, it’s not sustainable because its 32-bit address space provides only about 4.3 billion unique addresses, and with growing number of devices connecting to the internet it’s not sustainable.