IPSec Mechanism

The Internet Protocol Security (IPSec) mechanism can be used with LAN hosts or security gateways located at the interface between the LAN and WAN networks. The IPSec mechanism is deployed in the security gateways of each LAN network. The IPSec mechanism is deployed from end‐to‐end, in each host. The IPSec mechanism introduces two IPv4 or IPv6 header extensions: the Authentication Header (AH) and the Encapsulating Security Payload (ESP). The ESP extension provides a confidentiality service in addition to those offered by the AH extension. The variable fields of the IPv6 header are set at zero for the authentication digest calculation. Security services are provided by the use of AH or ESP extensions. The IKEv2 protocol combines the functionalities defined in IKEv1 and Internet Security Association and Key Management Protocol (ISAKMP) while removing unnecessary processes.