With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
rprSpanCurrentGroup
rpr Span Current Group
1.0.8802.17.1.1.2.1.12
Collection of objects counting MAC span current statistics.
Back to IEEE-802DOT17-RPR-MIB MIB page.
IPHost Network monitor allows you to monitor rprSpanCurrentGroup 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.