CCNA IPv6 Addressing — Everything You Need to Know
Why Does IPv6 Exist? IPv4 uses 32-bit addresses, which gives approximately 4.3 billion unique addresses. With billions of internet-connected devices globally, IPv4 address space is exhausted. IPv6 solves this with 128-bit addresses, producing approximately 340 undecillion unique addresses — enough for every device on Earth for the foreseeable future. Beyond address space, IPv6 also eliminates the need for NAT (Network Address Translation), simplifies header structure for faster routing, and includes built-in support for IPsec. IPv6 Address Structure An IPv6 address is 128 bits long, written as eight groups of four hexadecimal digits, separated by colons: 2001:0db8:0000:0000:0000:ff00:0042:8329 Two shortening rules reduce this to a more readable format: • Rule 1 — Leading zeros in any group can be dropped. 0db8 becomes db8. 0000 becomes 0. • Rule 2 — One consecutive sequence of all-zero grou...