With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
vrPpTbpBlockingDiscards
Virtual Router Passport Tbp Blocking Discards
This attribute is indicative of the number of incoming frames that were discarded because the bridge port was in the blocking state. This counter wraps around its maximum value of 4294967295.
Back to Nortel-Magellan-Passport-BridgeMIB MIB page.
IPHost Network monitor allows you to monitor vrPpTbpBlockingDiscards 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 speech servers right now.