With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cfwBufferStatSize
Cisco Firewall Buffer Statistic Size
1.3.6.1.4.1.9.9.147.1.2.2.1.1.1
This object contains the size of the set of buffers for which this row contains the statistics given by cfwBufferStatType.
Back to CISCO-FIREWALL-MIB MIB page.
IPHost Network monitor allows you to monitor cfwBufferStatSize on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco multiplexers right now.