ABSTRACT
There is an additional need for support for IPv6 hosts and routers that need to interoperate with legacy IPv4 hosts; an overview of such mechanisms for this purpose is provided in [RFC2893]. That RFC defines the following types of nodes with respect to the transition to IPv6:
IPv4-only node: A host or router that implements only IPv4. An IPv4-only node does not understand IPv6. The installed base of IPv4 hosts and routers are examples of IPv4-only nodes.
