With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
vrPpIpPortMaxTxUnit
Virtual Router Passport Ip Port Max Tx Unit
This attribute specifies the IP MTU (Maximum Transmission Unit) supported by this IpPort. The specified MTU must be within the valid range for the IpPort media type.
Back to Nortel-Magellan-Passport-IpMIB MIB page.
IPHost Network monitor allows you to monitor vrPpIpPortMaxTxUnit 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 secure routers right now.