With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
x25DteInWindowSize
x25 Dte In Window Size
1.3.6.1.4.1.562.2.4.1.90.23.1.3
This attribute specifies the maximum receive window size for the X.25 interface. A window size greater than 7 is only valid when the packetSequencing attribute is set to modulo128.
Back to Nortel-Magellan-Passport-X25DteMIB MIB page.
IPHost Network monitor allows you to monitor x25DteInWindowSize 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.