Tunneling is often used in networking and refers to encapsulating one packet (or frame) into another packet (or frame). One example is a VPN where we encapsulate the original IP packet into a new IP packet, encrypting the original IP packet so that nobody can see it. Another example is encapsulating IPv6 packets in IPv4 packets. This allows you to bridge two IPv6 networks over a non-IPv6 network that is using IPV4, such as the Internet.