With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
vrIpNsLocalInFilter
Virtual Router Ip Ns Local In Filter
The localInFilter is the second filter point which uses by network administrator to perform a common action on all IP packets that physically arrive over a specific logical interface, regardless of the packet's stated source or destination. Typical uses for a localInFilter include verifying that known Ethernet media source addresses match known IP addresses, or confirming that the IP packet source addresses of received IP packet fall within a narrow range.
Back to Nortel-Magellan-Passport-IpMIB MIB page.
IPHost Network monitor allows you to monitor vrIpNsLocalInFilter 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 modems right now.