Research on tunneling techniques in virtual private networks

It is a trend of virtual private networks (VPN) to be used for information exchange between enterprises, between branches of enterprises and between enterprises and their employees instead of traditional dial networks and leased lines. The tunneling technique is the key technique to implement VPN. With the VPN implementation requirements in mind, we perform comparative research on the existing tunneling protocols including GRE, L2TP, IPSec and IP/IP. We also propose an integrated scheme of tunneling mechanism that supports VPN under the current condition.