This read-create Unsigned32 sets the Committed Burst Size (CBS) of a specific per-COS QoS Shaper on an access port, the token-bucket depth for committed-rate traffic. Admins tune CBS to control how large a momentary burst of committed-rate traffic the access-port shaper can smooth out without dropping or delaying frames excessively. For example, an access port's voice COS shaper handling occasional call-setup signaling bursts might need a modest cmAccPortQosShaperCBS to absorb those brief spikes without impacting steady-state voice traffic.