IPsec Applied to Outbound Packet Process shows how an IP packet proceeds when IPsec has been invoked on an outbound packet. The flow diagram illustrates where authentication header (AH) and encapsulating security payload (ESP) entities can be applied to the packet. Subsequent sections describe how to apply these entities, as well as how to choose the algorithms.
IPsec Applied to Inbound Packet Process shows the IPsec inbound process.
Figure 6 IPsec Applied to Outbound Packet Process
Figure 7 IPsec Applied to Inbound Packet Process