Which technology is used to carry IPv6 packets over IPv4 by encapsulating inside GRE?

• A. Switch
• B. NGFW
• C. Generic Routing Encapsulation (GRE) Tunnel
• D. Wireless Controller

Answer: (C)

Carrying IPv6 over IPv4 uses a tunneling approach: wrap the IPv6 packet inside another protocol so it can travel through an IPv4 network. Generic Routing Encapsulation creates exactly that kind of tunnel. It sets up a tunnel between two endpoints, with an outer IPv4 header that routes the packet and an inner IPv6 payload. The GRE header marks the encapsulated IPv6 traffic, and the receiving end decapsulates to restore the original IPv6 packet. This lets IPv6 traverse an IPv4 network without needing the intermediate network to support IPv6 natively. The other options don’t provide this encapsulation capability: a switch operates at Layer 2, a firewall enforces security policies, and a wireless controller manages wireless access points.