This read-create INTEGER, in bytes, sets the committed burst size the port shaper allows before enforcing the configured CIR rate, and is not applicable when the shaper is disabled. An admin tunes this to allow brief traffic bursts through the shaper without immediately smoothing them, accommodating naturally bursty applications while still capping sustained throughput. For example, an admin shaping a port to a steady rate but wanting to avoid choking short bursts from a backup job would set this burst size generously enough to pass those bursts unshaped, relying on the CIR to control the sustained average.