With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
vrPpTbpDesignatedBridge
Virtual Router Passport Tbp Designated Bridge
This attribute specifies the identifier of the bridge that this port considers to be the designated bridge.
Back to Nortel-Magellan-Passport-BridgeMIB MIB page.
IPHost Network monitor allows you to monitor vrPpTbpDesignatedBridge 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 switches right now.