cisco QoS mib

[yuan]

we recently implemented new QoS policy in the netework. To monitor, we deployed CiscoWorks QPM to manage the source routers where QoS policies are implemented, and two sniffers (one near the sources and one near the receivers). Note that in between the source and the receiver, there are half a dozen routers unmanaged by QPM.

However, the data collected by QPM revealed a different result from what was collected by the sniffers. For example, while QPM showed 0.4% WRED drop for a certain policy, sniffers showed 10% drops

In search for a possible explanation for the difference, we think it's either because 1)majority of the packets were dropped by the devices unmanaged by QPM or 2)the traffic was too short and bursty to be picked up by the QoS MIB

Can anyone explain to me how QoS MIB gets its data?

[smalkeric]

As you said there is a difference in % of WRED drops when measured with QPM and sniffers beause of the majority of the packets were dropped by the devices unmanaged QPM. That could be the reason. QOS MIB is not a possible reason because the the MIB just gives the information on the QOS applied to the interface at a particular instant of time.