Called Station ID

From RFC3580:

3.20. Called-Station-Id
For IEEE 802.1X Authenticators, this attribute is used to store the
bridge or Access Point MAC address in ASCII format (upper case only),
with octet values separated by a "-". Example: "00-10-A4-23-19-C0".
In IEEE 802.11, where the SSID is known, it SHOULD be appended to the
Access Point MAC address, separated from the MAC address with a ":".
Example "00-10-A4-23-19-C0:AP1".