systemd services and startup daemons, and port numbers are explained with the following formats:
Name of Unit.
Function of Unit.
Effect if Unit is stopped.
Prior Unit that the local Unit needs. If the specified Unit failed to start, the local Unit does not start either.
Prior Unit that the local Unit needs. Even if the specified Unit failed to start, the local Unit starts.
Another Unit that starts after the local Unit.
Another Unit that starts before the local Unit.
Daemon started by Unit.
Port number.
Protocol - TCP or UDP.
"s" if port sends data, "r" if it receives data, "s, r" for both.
Utilized network - any of Cluster interconnect, administrative LAN, or public LAN.
Node that uses the port.
Port number of communication target.
Node or device that uses the port of the communication target.
Remarks.