The text representation of IPv6 address prefixes is similar to the way IPv4 address prefixes are written in Classless Inter-Domain Routing (CIDR) notation. An IPv6 address prefix is represented by the notation ipv6-address/prefix-length where:

ipv6-address

An IPv6 address in any of the notations listed.

prefix-length

A decimal value specifying how many of the leftmost contiguous bits of the address comprise the prefix.

The following examples are legal representations of the 60-bit prefix 20010DB80000CD3 (hexadecimal):

2001:0DB8:0000:CD30:0000:0000:0000:0000/60
2001:DB8::CD30:0:0:0:0/60
2001:DB8:0:CD30::/60

The following examples are not legal representations of the preceding prefix:

• 2001:DB8:0:CD3/60

  Leading zeros might be dropped, but not trailing zeros, within any 16-bit chunk of the address.

• 2001:DB8::CD30/60

  Address to the left of the forward slash (/) expands to 2001:DB8:0000:0000:0000:0000:0000:CD30.

When writing both a node address and a prefix of that node address (for example, the node's subnet prefix), the two can be combined as in the following examples:

• Node address - 2001:DB8:0:CD30:123:4567:89AB:CDEF
• Subnet number - 2001:DB8:0:CD30::/60
• Combination of node address and subnet number - 2001:DB8:0:CD30:123:4567:89AB:CDEF/60