Intrusions: What is PC identification here - not IP address, not MAC address, hex format??

Getting frequent intrusion blocks typically as follows:

RiskName: PortScan

Traffic Description: UDP, port 5355

 

Attacking & Destination computers are identified with a 4-place hex prefix, double colon, followed by four colon-delimited 4-place hex strings, a comma, and a 5-6 decimal number (port number?).

 

What the heck are those identifiers?