With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
vrBrSrbStpDesignatedRoot
Virtual Router Br Srb Stp Designated Root
This attribute specifies the identifier of the bridge that this bridge treats as the root of the spanning tree topology. The root of the spanning tree topology is chosen through exchange.
Back to Nortel-Magellan-Passport-BridgeMIB MIB page.
IPHost Network monitor allows you to monitor vrBrSrbStpDesignatedRoot 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.