With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cdxCmtsCmCurrCpeNumber
Cisco DOCSIS Cmts Cable Modem Current Cpe Number
1.3.6.1.4.1.9.9.116.1.3.6.1.2
The current number of CPEs connecting to the modem. The value 0 means no hosts connecting to the modem.
Back to CISCO-DOCS-EXT-MIB MIB page.
IPHost Network monitor allows you to monitor cdxCmtsCmCurrCpeNumber 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.