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2.9.1. Unicast Addresses

Global Unicast Address (GUA): Routable on the internet (like public IPv4)

  • Structure: 48-bit Global Routing Prefix + 16-bit Subnet ID + 64-bit Interface ID
  • ISPs assign the prefix; organizations assign subnets; hosts get interface IDs

Unique Local Address (ULA): Private addressing (like RFC 1918)

  • FD00::/8 is commonly used
  • Not routable on the internet

Link-Local Address: Automatically configured on every IPv6 interface

  • Required for IPv6 to function
  • Only valid on the local link (not routed)
  • Used for neighbor discovery, routing protocols