IPv6 Notation

IPv6 is the latest version of IP that is suitable for large-scale IP networks. IPv6 supports a 128-bit address to allow 2128, or approximately 3.4×1038 addresses while IPv4 supports only 232 addresses.

The IP address of the IPv6 host is always represented as eight groups of four hexadecimal digits separated by colons. For example 2001:0db8:0a0b:12f0:0000:0000:0000:0001. However, the IPv6 notation can be abbreviated to compress one or more groups of zeroes or to compress leading or trailing zeroes.

The following examples show various representations of the address 2001:0db8:0a0b:12f0:0000:0000:0000:0001

• Valid format—2001:db8:a0b:12f0::0:0:1
• Invalid format—2001:db8:a0b:12f0::::0:1. The “::” sign appears only once in an address.
• With leading zeros omitted—2001:db8:a0b:12f0:0:0:0:1
• Switching from upper to lower case—2001:DB8:A0B:12f0:0:0:0:1

IPv6 uses a "/" notation which describes the number of bits in netmask Netmask is a 32-bit mask used for segregating IP address into subnets. Netmask defines the class and range of IP addresses. as in IPv4.

2001:db8::1/128 – Single Host

2001:db8::/64 – Network