As with the IPv4’s Unicast, Broadcast and Multicast addresses that defines the basics of communication and connectivity on the internet, IPv6 managed to remove the broadcast (because of the difficulties it causes on a network through looping) from the trio and introduced Anycast.
Lets look at these IPv6 address types in detail below:
Unicast Address: Packets addressed to a unicast address is destined for a single interface. This can also refered to as one –to-one ipv6 address. Other different type of unicast addressing is Global, Link local, Site local.
Global Unicast Address: An IPv6 unicast address is globally routable on the public internet. It shares the same address format as an IPv6 anycast address. Global unicast addresses are assigned by the Internet Assigned Numbers Authority (IANA).
Link-local Addresses: These are private address that is not meant to be routed on the internet. They can be used locally by private or temporary LANs for sharing and distribution of file among devices on the LAN.
Unique local address: This type of ipv6 address also not intended to be routed on the public internet. Unique local is a replacement of site-local address, that allows communication within a site while being routable to a multiple local networks.
Multicast Address: This can also be refered to as One-to-Many. Packets addressed to multicast address are delivered to all interface identified by the multicast address. Multicast address types are easily notable because they normally begins with FF.
Anycast: This form of ipv6 address is similar to the multicast address with a slight difference. Anycast address can also be refered to as One to Nearest. It can be used to address packets meant for multiple interfaces; but usually it sends packets to the first interface it finds as defined in the routing distance. This means it send packets to the closest interface as determined by routing protocols.
Anycast address is a very special ipv6 addressing type such that it can also be used to deliver a packet to more than one interface which also helped earn the name as One-to-One or Many address!
Loopback Address: Just as in IPv4, a provision has been made for a special loopback IPv6 address for testing. However, in IPv6 there is just one address, not a whole block, for this function. The loopback address is 0:0:0:0:0:0:0:1, which is normally expressed using zero compression as “::1“.
Special IPv6 addresses
Just like in IPv4, IPv6 have some addresses specially reserved for specific use. Below are example of these addresses:
1. 0:0:0:0:0:0:0:0 can be represented as ::
This is equivalent to ipv4 version of 0.0.0.0.which is the host source address use during stateful configuration.
2. 0:0:0:0:0:0:0:1 = 1 – This is 127.0.0.1 equivalent in IPv4.
3. 20000::/3 – The global unicast address range.
4. FEC00::/7 – The unique local address range.
5. FE80::/10 – Link-local unicast address range.
6. FF00::/8 – The multicast range.
7. 3FFF:FFFF::/32 and 2001:0DB8::/32 – Reserved address range for examples and documentation.
8. 2002::/16 – this address range are normally use during the ipv6 transition or migration(6to4) configuration.