What is the size of the Internet Protocol Version 6 (IPv6) address?

Length: 128 bits (compared to IPv4’s 32 bits).
Format: Written as eight groups of four hexadecimal digits, separated by colons.
Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
Why 128 Bits?
IPv4 Limitation: IPv4 uses 32 bits, which allows about 4.3 billion unique addresses. With the rapid growth of the internet, this pool became insufficient.
IPv6 Expansion: By using 128 bits, IPv6 provides
\(2^{128} = 3.4\times 10^{38}\)
possible addresses — an astronomically large number, enough to assign trillions of addresses to every person on Earth.
Benefits of Larger Address Space
Scalability: Supports the massive growth of devices (IoT, smartphones, sensors).
Hierarchical Addressing: Easier routing and network management.
Future-Proofing: Ensures the internet won’t run out of addresses for centuries.
In summary: An IPv6 address is 128 bits long, chosen to overcome IPv4’s limitations and to provide a practically unlimited supply of unique addresses for the future of the internet.