An IPv6 overlay tunnel is required to communicate with isolated IPv6 networks across an IPv4 infrastructure. There are currently five IPv6 overlay tunnel types. Which three IPv6 overlay tunnel statements are true? (Choose three)
正解:B,D,F
Explanation/Reference: Explanation: B: Overlay tunnels can be configured between border routers or between a border router and a host capable of supporting IPv4 and IPv6. D. Cisco IOS supports manual, generic routing encapsulation (GRE), IPv4-compatible, 6to4, and IntraSite Automatic Tunnel Addressing Protocol (ISATAP) overlay tunneling mechanisms. F: Overlay tunneling encapsulates IPv6 packets in IPv4 packets for delivery across an IPv4 infrastructure.