With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
stpxRSTPPortRoleEntry
stpx RSTP Port Role Entry
1.3.6.1.4.1.9.9.82.1.12.2.1
An entry containing the port role information for the RSTP protocol on a port for a particular Spanning Tree instance.
Back to CISCO-STP-EXTENSIONS-MIB MIB page.
IPHost Network monitor allows you to monitor stpxRSTPPortRoleEntry 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.