With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cbQosREDTailDropByte
Cisco Class Based Qos RED Tail Dropped Byte
1.3.6.1.4.1.9.9.166.1.20.1.1.11
The lower 32 bits count of bytes dropped when the number of packets in the associated queue was greater than the maximum threshold.
Back to CISCO-CLASS-BASED-QOS-MIB MIB page.
IPHost Network monitor allows you to monitor cbQosREDTailDropByte on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco switches right now.
