A Security Association is a __________ way connection?

A Security Association (SA) in the context of IPsec is a one-way logical connection used for secure communication between two endpoints. IPsec requires two SAs to establish a secure, bidirectional communication channel—one for each direction (inbound and outbound). This arrangement ensures that each direction is independently secured, with its own set of security parameters.References:

RFC 4301, "Security Architecture for the Internet Protocol".