IPv6 global unicast addresses

IPv6 global addresses are similar to IPv4 public addresses. As the name implies, they are routable on the internet. Currently IANA has assigned only 2000::/3 addresses to the global pool.

A global IPv6 address consists of two parts:

  • subnet ID – 64 bits long. Contains the site prefix (obtained from a Regional Internet Registry) and the subnet ID (subnets within the site).
  • interface ID – 64 bits long. typically composed of a part of the MAC address of the interface.


Here is a graphical representation of the two parts of an global IPv6 address:

global unicast ipv6 address

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