Encapsulation; Figure 14-2 Ipsec Architecture - ZyXEL Communications ZyWALL 10W User Manual

ZyWALL Series Internet Security Gateway

Figure 14-2 IPSec Architecture

14.2.1 IPSec Algorithms
The ESP (Encapsulating Security Payload) Protocol (RFC 2406) and AH (Authentication Header) protocol
(RFC 2402) describe the packet formats and the default standards for packet structure (including
implementation algorithms).
The Encryption Algorithm describes the use of encryption techniques such as DES (Data Encryption
Standard), AES (Advanced Encryption Standard) and Triple DES algorithms.
The Authentication Algorithms, HMAC-MD5 (RFC 2403) and HMAC-SHA-1 (RFC 2404, provide an
authentication mechanism for the AH and ESP protocols. Please see section 15.2 for more information.
14.2.2 Key Management
Key management allows you to determine whether to use IKE (ISAKMP) or manual key configuration in
order to set up a VPN.

14.3 Encapsulation

The two modes of operation for IPSec VPNs are Transport mode and Tunnel mode.
Introduction to IPSec 14-3