This read-only counter tracks the number of times the channel's egress reassembly buffer ran out of cells to play out (underflowed) before new data arrived, a condition not supported for tracking on CESM-8P due to AAL1 SAR limitations. An administrator on a card type where this applies watches for underflows as a sign that cesCDVRxT (the configured jitter tolerance) or cesBufMaxSize is set too small for the actual network jitter being experienced. Frequent underflows typically manifest as audible glitches or data errors on the emulated circuit and often prompt raising the buffer size or jitter tolerance.