With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
rprSpanIntervalInUcastClassBEirFrames
rpr Span Interval In Ucast Class B Eir Frames
1.0.8802.17.1.1.1.3.2.1.11
The number of received (PHY to MAC) classB EIR unicast frames in a particular interval in the past 24 hours.
Back to IEEE-802DOT17-RPR-MIB MIB page.
IPHost Network monitor allows you to monitor rprSpanIntervalInUcastClassBEirFrames on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco firewalls right now.