With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
timeSyncSourcesTable
time Sync Sources Table
1.3.6.1.4.1.3646.1300.2.1.2.1.391
This attribute indicates the IP addresses of the network time servers that this module synchronizes with. XNTP uses the clock values of the network time servers to set its moduleTime.
Back to Nortel-Magellan-Passport-TimeMIB MIB page.
IPHost Network monitor allows you to monitor timeSyncSourcesTable on Allied Telesis device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Nortel modems right now.