BUFFER HEADROOM-BASED RESULT DETERMINATION SYSTEM

A headroom-based result determination system includes first and second ports connected via a link, and a buffer for the first port. A headroom-based result determination subsystem monitors data stored in the buffer that was received in data packets each having a worst-case data packet size and transmitted at a maximum packet rate for a link speed of the link, determines that a buffer threshold is reached and, in response, generates a pause instruction. The headroom-based result determination subsystem then transmits the pause instruction to the second port, measures a first amount of data stored in the buffer subsequent to generating the pause instruction, and generates a headroom-based result by adding the first amount of data, a second amount of data equal to a maximum transmission size of the first port, and a third amount of data equal to a maximum transmission size of a class of the data received at the first port.