With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
clcFdbVlanMacUsage
Cisco L2 Control Fdb Vlan Mac Usage
1.3.6.1.4.1.9.9.313.1.1.7.1.1
The usage of the MAC addresses in the specific forwarding table for this VLAN. It indicates the number of MAC addresses in this VLAN for a forwarding table.
Back to CISCO-L2-CONTROL-MIB MIB page.
IPHost Network monitor allows you to monitor clcFdbVlanMacUsage 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.