This is regarding LACP System Priority.
From my research I could find the following info pertaining to system priority.
LACP combines the System Priority value with the MAC address of the switch to create a System ID. The switch with the lower System ID becomes the master switch, and the other switch must fall into line with whatever decision the master makes reg ports to be used in LACP.
My query here is does this negotiation is indicated via a field in packet saying one switch is master and other is standby.