This setting holds the Connectivity Association Key Name (CKN), an identifying label (rather than the secret itself) used as part of the pre-shared-key configuration for MACsec, the IEEE 802.1AE Layer-2 encryption standard that protects Ethernet frames between two directly connected devices. An administrator configures this name on both ends of a MACsec-protected link, and it must match on both sides along with the actual key value for the MACsec session to establish successfully. For example, an administrator securing a link between two data-center switches might set this to a label like "dc-link-01", which must be configured identically on the switch at the other end of that link.