With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
bstunRouteRxBytes
Cisco Blocked Serial Tunneling Route Rx Bytes
1.3.6.1.4.1.9.9.35.1.4.1.1.10
Count of bytes received from the serial interface with this station's address.
Back to CISCO-BSTUN-MIB MIB page.
IPHost Network monitor allows you to monitor bstunRouteRxBytes 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.