In tunneling, the data are broken into smaller pieces called packets as they move along the tunnel for transport. As the packets move through the tunnel, they are encrypted and another process called encapsulation occurs. The private network data and the protocol information that goes with it are encapsulated in public network transmission units for sending. The units look like public data, allowing them to be transmitted across the Internet. Encapsulation allows the packets to arrive at their proper destination. At the final destination, de-capsulation and decryption occur.

There are various protocols that allow tunneling to occur, including:

• Point-to-Point Tunneling Protocol (PPTP): PPTP keeps proprietary data secure even when it is being communicated over public networks. Authorized users can access a private network called a virtual private network, which is provided by an Internet service provider. This is a private network in the “virtual” sense because it is actually being created in a tunneled environment.
  
• Layer Two Tunneling Protocol (L2TP): This type of tunneling protocol involves a combination of using PPTP and Layer 2 Forwarding.

Tunneling is a way for communication to be conducted over a private network but tunneled through a public network. This is particularly useful in a corporate setting and also offers security features such as encryption options.