What is the primary feature of IPv6?

The primary feature of IPv6 is its use of 128-bit addresses. This significantly expands the address space compared to its predecessor, IPv4, which uses 32-bit addresses. The vast increase in address space provided by IPv6 is crucial due to the exponential growth of devices connected to the internet. It allows for a nearly limitless number of unique IP addresses, ensuring that every device can have its own unique identifier, which is essential for the functioning of the internet and the provision of services to an ever-expanding network of users and devices.

Additionally, the larger address size facilitates better routing and allocation of addresses, supports improved mobility features, and allows for more efficient network configurations. This evolution in addressing is a fundamental enhancement that addresses the challenges and limitations faced by the existing IPv4 system.