Template:References

Microsoft (2016). VPN Tunneling protocols. . Retrieved from https://technet.microsoft.com/en-us/library/cc771298(v=ws.10).aspx

Mitchell, B. (2014, December 20). VPN Tunneling virtual private networks Tutorial. Retrieved March 30, 2016, from Tech, http://compnetworking.about.com/od/vpn/a/vpn_tunneling.htm