With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
atmIfVptUniAddrPnniInfoReachability
atm If Vpt Uni Address Pnni Info Reachability
This attribute indicates whether the address is internal or exterior. An internal reachable address is an address of a destination that is directly attached to the logical node advertising the address. An exterior reachable address is an address that can be reached through a PNNI routing domain, but which is not located in that PNNI routing domain.
Back to Nortel-Magellan-Passport-AtmUniMIB MIB page.
IPHost Network monitor allows you to monitor atmIfVptUniAddrPnniInfoReachability 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.