What is the significance of an IPv6 address having a long format?

The long format of an IPv6 address is significant because it supports a vastly larger address space compared to IPv4. An IPv4 address, composed of 32 bits, allows for approximately 4.3 billion unique addresses, which has become insufficient due to the exponential growth of devices connected to the internet. In contrast, IPv6 utilizes 128 bits for its address structure, which theoretically allows for 340 undecillion (or 3.4 x 10^38) unique addresses. This immense increase in address space is crucial for accommodating the growing number of Internet of Things (IoT) devices, mobile devices, and other endpoints in the network.

Additionally, the long format incorporates a structured representation of the address, which can provide benefits in various network configurations, including hierarchical addressing and more efficient routing, but the primary significance lies in the expanded availability of IP addresses that can be assigned to devices. This characteristic is essential to ensure continued growth and connectivity on the internet without the constraints faced under IPv4.