Which two statements about GRE tunnels are true? (Choose two.)
A.
GRE can be used to tunnel non-IP protocols, such as IPX.
B.
GRE can provide encrypted communication.
C.
GRE adds overhead of 16 bytes per packet.
D.
GRE can be used to tunnel IPv6 traffic.
Explanation:
GRE Tunnels for Non-IP Protocol Transport
Providers can deploy GRE to support the transport of non-IP protocols over third-party private IP infrastructure or even over the public Internet.Tunneling IPv6 over IPv4
Using either GRE or IP-IP tunneled across an IP network, providers can tunnel IPv6 packets over IPv4 infrastructure, providing a migration path to IPv6 as defined in RFC 2893.