With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
ccdsgIfDownstreamTable
CISCO CABLE DSG If Downstream Table
1.3.6.1.4.1.9.10.999.3.1
The DSG Downstream Table associates a Tunnel Index with a DOCSIS downstream channel interface index (ifIndex). It could have a same tunnel associated to multiple downstream channel and vise versa.
Back to CISCO-CABLE-DSG-IF-MIB MIB page.
IPHost Network monitor allows you to monitor ccdsgIfDownstreamTable on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco routers right now.