With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cGgsnExtHistDownstreamPktCount
cisco Gateway GPRS Support Node Ext History Downstream Packet Count
1.3.6.1.4.1.9.9.647.1.1.17.1.7
This object represents the historical number of downstream packets sent in a specific sampling period specified by cGgsnExtThruputInterval.
Back to CISCO-GGSN-EXT-MIB MIB page.
IPHost Network monitor allows you to monitor cGgsnExtHistDownstreamPktCount on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco wireless switches right now.