IPv6 is available to networks in a variety of ways. We make a distinction between environments with native IPv6 and those which provide IPv6 through a tunnel.
- Native IPv6: Native IPv6 describes a network that communicates to the outside only via IPv6. Users with IPv4 addresses can only access this network by communicating through a gateway that mediates between IPv6 and IPv4 networks.
- IPv6 via dual stack: Dual stack refers to the parallel operation of IPv4 and IPv6 in a network. A router mediates between devices that "speak" only IPv4 or IPv6. The clients select the protocol they need.
- IPv6 tunneling: If a router does not have IPv6 Internet access, it can still access IPv6 networks by means of a tunnel.