mscTraceSessionFramesDiscarded counts the number of trace frames discarded because the trace queue was full, not counting frames dropped while the queue was blocked, and it wraps when it exceeds its maximum value. Admins use this counter to quantify data loss in a trace session caused by queue overflow specifically, distinguishing it from the blocked-queue case reported only via mscTraceSessionQueueState. For example, a nonzero and climbing mscTraceSessionFramesDiscarded during a trace tells an admin the receiver or VC is too slow to keep up with the queue, and some captured frames were lost as a result.