With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
fcmPortClass3Discards
fcm Port Class3 Discards
1.3.6.1.2.1.10.56.1.4.1.20
The number of Class 3 frames that were discarded upon reception at this port.
Back to FC-MGMT-MIB MIB page.
IPHost Network monitor allows you to monitor fcmPortClass3Discards on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco routers right now.