IPsec defines a set of security mechanisms and procedures that can be used to secure communications between two hosts on the network level. It is a set of communication rules designed to act independently of higher layer protocol functions compensating for link-based protection services for the data stream. The provision of security functions on the packet level has made IPsec the foundation for the establishment of Virtual Private Networks. Companies and other private organisation are able to set up secured dedicated communication channels, defining the appropriate policies governing their connection as to the traffic allowed to traverse the network.