In IPsec, an SA (Security Association) is uniquely identified by three parameters.

Comprehensive and Detailed In-Depth Explanation:

IPsec (IP Security Protocol) establishes Security Associations (SAs) for encrypted communication.

An SA is uniquely identified by a 3-tuple:

SPI (Security Parameter Index) → Identifies the SA.

Destination IP Address → Specifies the receiving device.

Security Protocol ID → Indicates whether AH (Authentication Header) or ESP (Encapsulating Security Payload) is used.

A. Key exchange protocol is not part of the SA 3-tuple. It is used during IKE (Internet Key Exchange) but is not part of the SA itself.

???? Reference: Huawei HCIA-Datacom Study Guide, IPsec Security Association and SA Identification.