Server time protocol (STP) messages and methods of exchange thereof are p rovided for facilitating synchronization of processing units of a timing net work. The STP messages include exchange time parameters (XTP) commands and r esponses, and STP control (STC) commands and responses. XTP message exchange processing includes: generating an XTP message command at a first processin g unit including a command transmit timestamp field set bythe first processi ng unit and a command receive timestamp field which is unset by the first pr ocessing unit; transmitting the XTP message command to a second processing u nit; setting the command receive timestamp field in the XTP command with the time the XTP command is received at the second processing unit; and generat ing an XTP message response at the second processing unit, the message respo nse including the command transmit timestamp set by the first processing uni t and the command receive timestamp set by the second processing unit.
