With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cbQosQueueingDiscardByte
Cisco Class Based Qos Queueing Discard Byte
1.3.6.1.4.1.9.9.166.1.18.1.1.4
The lower 32 bits count of octets, associated with this class, that were dropped by queueing.
Back to CISCO-CLASS-BASED-QOS-MIB MIB page.
IPHost Network monitor allows you to monitor cbQosQueueingDiscardByte on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco firewalls right now.