This read-create value holds the Committed Burst Size, in bits, for this traffic descriptor. Bc caps how large a single burst can be while still counting as within the committed rate, so raising it lets a customer send short bursts well above their average CIR without those bursts being marked non-conformant, at the cost of the switch needing more buffer to smooth the burst. A CIR of 512 Kbps paired with a Bc of 16,000 bits lets a burst of roughly two seconds' worth of traffic through unmarked before the excess-burst allowance takes over.