You have two facilities and both use IPv6 addressing internally. However, both facilities are connected to the Internet via IPv4. What is one recommended method you can use to communicate between the facilities over the Internet?

A 6to4 tunnel can be achieved between the routers. This encapsulates the IPv6 header in an IPv4 header so that it can be routed across the Internet. A dedicated leased line and Frame Relay are wide area network (WAN) connectivity methods. Dual stack means that a host or router will have both IPv4 and IPv6 configured, but it will not allow both facilities to communicate over the Internet via IPv6.