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A technology that enables one network to send its data via another network's connections. Tunneling works by encapsulating a network protocol within packets carried by the second network. For example, Microsoft's PPTP technology enables organizations to use the Internet to transmit data across a virtual private network (VPN). It does this by embedding its own network protocol within the TCP/IP packets carried by the Internet. For those that prefer formal wording, tunneling is also called encapsulation. See L2F and L2TP, two additional but competitive to PPTP, tunneling technologies.