Introduction to type classification of IPV6 addresses

All types of IPV6 addresses are assigned to interfaces, not nodes. The IPV6 address is a 128-bit identifier for a single or set of interfaces, with three types:

(1) unicast (Unicast) address

An identifier for a single interface. Packets sent to a unicast address are sent to the interface identified by the address. For a node that has more than one interface, any one of its unicast addresses can be used as an identifier for that node. A IPV6 unicast address is an address clustered with contiguous bitmask, similar to CIDR's IPV4 address. There are several forms of unicast address assignment in IPv6, including all clustered global unicast addresses, NSAP addresses, IPX rating addresses, site-local addresses, link-local addresses, and host addresses running IPV4. The following two special addresses are available in a unicast address:

Address not identified

Unicast address 0:0:0:0:0:0:0:0 is called an indeterminate address. It cannot be assigned to any node. An example of an application is that when the host is initialized, the source address field of any IPV6 package it sends can be placed on an indeterminate address before the host has obtained its own address. The uncertain address cannot be used as the destination address in the IPV6 package, nor can it be used in the IPv6 road header;

Loopback address

Unicast address 0:0:0:0:0:0:0:1 is called a loopback address. The node uses it to send IPV6 packets to itself. It cannot be assigned to any physical interface.

(2) Anycast (anycast) address

An identifier for a set of interfaces, which generally belong to different nodes. Packets destined for Anycast addresses are sent to one of the interfaces identified by the address (the routing protocol measures the nearest). The following restrictions exist for IPV6 anycast addresses:

• Anycast addresses cannot be used as source addresses, but only as destination addresses;

• Anycast addresses cannot be assigned to IPV6 hosts and can only be assigned to IPV6 routers;

IPV6 anycast Address

(3) Multicast (multicast) address

An identifier for a set of interfaces, which generally belong to different nodes. Packets destined for the multicast address are sent to all interfaces identified by the address. 11111111 at the beginning of the address identifies the address as a multicast address.

IPV6 Multicast Address

There is no broadcast address in the IPV6, and its function is being replaced by a multicast address. In addition, in IPv6, any field that is full of "0" and "1" is a valid value unless it is specifically excluded. In particular, a prefix can contain a "0" value field or End with "0". A single interface can specify multiple IPV6 addresses (unicast, anycast, multicast) or ranges of any type.