IPsec security associations (SA)
If a packet is IPsec-protected, there must be an IPsec security association (SA) for it. A security association defines how an IP packet from one host to another is protected. Among many things, it defines the IPsec protocol to use, the authentication and encryption keys, and duration of key use.
An IPsec SA is unidirectional. A host can have an inbound SA and an outbound SA associated with particular IP packet protocols and services, and the IPsec protocol used to protect them.
When properly configured, the IPsec rules define the security associations for IP traffic to and from the HP Jetdirect print server and can ensure all traffic is secure.
HP Jetdirect Print Servers IPsec security associations (SA)