IPsec is a both a standard VPN framework as well as a specific protocol that has existed for quite some time and at its core has changed very little. It can trace its origins to somewhere about 1993 when the first IP VPN protocols, such as SP3, NLSP and swipe, were being developed. Eventually and early predecessor ka9q would contribute to the development of the first true IPsec designated by the IETF (Internet Engineering Task Force) in 1995, as recorded by Columbia University. 1998 would see additional revisions, sequencing and improvements in authentication; but it would not be until 2005 that IPsec really came into its own with the release of version 3, which again updated algorithms and larger sequencing numbers. Because it has never been bound by particular protocols, IPsec continues to be malleable allowing for newer and more secure technologies to be applied to its foundations.
IPsec is an extremely popular VPN protocol that functions using the IP protocol and its addressing and therefore can be considered a ‘Network Layer’ VPN protocol. IPsec is actually not bound to any particular protocols necessarily but is an openly available set of protocols and standards which