Configuration Guide Configuring IPv6
1080:0:0:0:8:800:200C:417A
These integers are hexadecimal, where A to F represent 10 to 15. Each integer in the address must be represented,
except the leading zeros in each integer. If an IPv6 address contains a string of zeros (as shown in the second and third
examples above), a double colon (::) can be used to represent these zeros. That is, 800:0:0:0:0:0:0:1 can be represented
as 800::1.
A double colon indicates that this address can be extended to a complete 128-bit address. In this approach, only when the
16-bit integers are all 0s, can they can be replaced with a double colon. A double colon can exist once in an IPv6 address.
In IPv4/IPv6 mixed environment, an address has a mixed representation. In an IPv6 address, the least significant 32 bits
can be used to represent an IPv4 address. This IPv6 address can be represented in a mixed manner, that is,
X:X:X:X:X:X:d.d.d.d, where X is a hexadecimal integer and d is a 8-bit decimal integer. For example,
0:0:0:0:0:0:192.168.20.1 is a valid IPv6 address. It can be abbreviated to :::192.168.20.1. Typical applications are
IPv4-compatible IPv6 addresses and IPv4-mapped IPv6 addresses. If the first 96 bits are 0 in an IPv4-compatible IPv6
address, this address can be represented as ::A.B.C.D, e.g., ::1.1.1.1. IPv4-compatible addresses have been abolished at
present. IPv4-mapped IPv6 addresses are represented as ::FFFF:A.B.C.D to represent IPv4 addresses as IPv6
addresses. For example, IPv4 address 1.1.1.1 mapped to an IPv6 address is represented as ::FFFF:1.1.1.1.
Since an IPv6 address is divided into two parts: subnet prefix and interface ID, it can be represented as an address with
an additional value according to an address allocation method like Classless Inter-Domain Routing (CIDR). The additional
value indicates how many bits (subnet prefix) in the address represent the network part. That is, the IPv6 node address
contains the prefix length. The prefix length is separated from the IPv6 address by a slash. For example, in
12AB::CD30:0:0:0:0/60, the prefix length used for routing is 60 bits.
Related Configuration
Configuring an IPv6 Address
No IPv6 address is configured on interfaces by default.
Run the ipv6 address command to configure an IPv6 address on an interface.
After configuration, a host can communicate with others using the configured IPv6 address based on DAD.
3.3.2 IPv6 Address Type
RFC 4291 defines three types of IPv6 addresses:
Unicast address: ID of a single interface. Packets destined to a unicast address are sent to the interface identified by
this address.
Multicast address: ID of an interface group (the interfaces generally belong to different nodes). Packets destined to a
multicast address are sent to all interfaces included in this address.
Anycast address: ID of an interface group. Packets destined to an anycast address are sent to one interface included
in this address (the nearest interface according to the routing protocol).
IPv6 does not define broadcast addresses.
These three types of addresses are described as follows:
Unicast Addresses
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