Return to Internet Protocol
“We define the “IPv6-only” status in a given part(s) of a network, depending on if there is actual native forwarding of IPv4, so IPv4 is not configured neither managed.”
This can be applied to a host, router, link, network (part), etc. It means that both, IPv4 and IPv6 are reachable, without specifying how.
This can be applied to a host, router, link, network (part), etc. It means that both, IPv4 and IPv6 are configured/used natively (without the need of transition mechanisms).
IPv6-only can be used only if, a complete network, end-to-end, is actually not natively forwarding IPv4, which will mean that no-IPv4 addresses are configured, neither used for management, neither the network is providing transition/translation support, neither there is IPv4 transit/peering. This is the end of the road of the IPv4-to-IPv6 transition, however we aren’t there yet, in general at the time of writing this document, unless we are referring to special or disconnected (from IPv4) networks.
IPv6-only WAN or access can be used only if the WAN or access network isn’t actually natively forwarding IPv4.
IPv6-only LAN(s) can be used only if the LAN(s), isn’t actually natively forwarding IPv4.
IPv6-only host/router can be used only if the host/router, isn’t actually using/forwarding IPv4, so IPv4 is unconfigured and/or disabled in the external facing interfaces. Internal interfaces, such as loopback, can still be using IPv4 (internally).
Transitional IPv6 host/router
Transitional IPv6 host/router is a dual-stack host/router with IPv6-only WAN where IPv4 service support is provided by means of transition mechanism, IPv4aaS (IPv4-as-a-service).