When the server is powered on, the clock synchronizes to the NTP server when the system is configured to listen to NTP multicast (the default). If the server and SP use the same NTP server, events logged in Oracle Solaris and on the SP can be correlated based on their time stamps. If the server and SP use different NTP servers, their times might drift, and correlating events in log files could become difficult. If you connect a domain to an NTP server other than the one used by the SP, ensure that both are low-stratum NTP servers that provide the same degree of accuracy.
Oracle ILOM Administrator's Guide for Configuration and Maintenance Firmware Release 3.2.x in Oracle ILOM 3.2 Documentation Library (http://www.oracle.com/goto/ilom321/docs)