With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
numberDown
number Down
The number of component instances that are down. A component is considered down when its administrative state is locked or its operational state is disabled.
Back to Nortel-Magellan-Passport-StateSummaryMIB MIB page.
IPHost Network monitor allows you to monitor numberDown 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.