What is the key difference between IPv4 and IPv6?

The key difference between IPv4 and IPv6 primarily lies in their capacity to support devices on a network. IPv4 utilizes a 32-bit addressing scheme, which limits the number of unique IP addresses to approximately 4.3 billion. This number became insufficient due to the exponential growth of internet-connected devices. In contrast, IPv6 employs a 128-bit addressing scheme, allowing for an immensely larger address space, theoretically accommodating about 340 undecillion unique addresses.

This vast difference addresses the increasing demand for IP addresses caused by the expanding number of devices connected to the internet, including smartphones, tablets, and IoT devices. Therefore, IPv4's limitations result in fewer available addresses compared to the extensive capabilities of IPv6, which is designed to support a virtually unlimited number of devices.