This read-only counter tracks the number of times the channel's egress reassembly buffer filled beyond capacity (overflowed), also not tracked on CESM-8P due to AAL1 SAR limitations. An administrator watches for overflows as a sign that cells are arriving faster or in larger bursts than the configured cesBufMaxSize can absorb. Persistent overflows suggest either increasing the buffer size or investigating why cell arrival timing is bursting beyond expected levels.