With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
vrIfTableEntryIfType
Virtual Router If Table Entry If Type
1.3.6.1.4.1.562.2.4.1.100.10.10.1.18
The type of interface, distinguished according to the physical/link protocol(s) immediately below the network layer in the protocol stack
Back to Nortel-Magellan-Passport-VirtualRouterMIB MIB page.
IPHost Network monitor allows you to monitor vrIfTableEntryIfType 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 multiplexers right now.