With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cagwCurrentFramedRouteSubs
Cisco's ASN Gateway Current Framed Route Subs
1.3.6.1.4.1.9.9.638.1.2.1.1.13
The number of subscribers using framed routes that have been inserted in IP routing table on gateway.
Back to CISCO-ASN-GATEWAY-MIB MIB page.
IPHost Network monitor allows you to monitor cagwCurrentFramedRouteSubs on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco mobile switches right now.