With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
shelfCardMsgBlockUsage
shelf Card Msg Block Usage
1.3.6.1.4.1.43.1.12.3.1.1.2.2.14.1.6
This attribute indicates the processor's current shared message block memory utilization (in kilobytes). If there is no shared memory on the card, this attribute indicates 0.
Back to Nortel-Magellan-Passport-ShelfMIB MIB page.
IPHost Network monitor allows you to monitor shelfCardMsgBlockUsage 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.