The following configura tion exists on a router on one end of an IPv6 tunnel. Which type of tunnel is created by this configuration?（） interface loopback 1 ip address 1.1.1.1 255.255.255.255 interface tunnel 2 ipv6 address 2000::1::/64 tunnel source loopback 1 tunnel destina tion 2.2.2.2 tunnel mode ipv6ip ipv6 eigrp 1
- A Automatic 6to4
- B Manually configured tunnel
- C ISATAP
- D GRE