BUFFER MANAGEMENT PROGRAM, RELAY DEVICE AND CONTROL METHOD

PROBLEM TO BE SOLVED: To suppress communication quality deterioration in a network performing a plurality of types of communication.SOLUTION: A relay device includes: a first buffer for storing a received frame; a discard unit for, on storing the received frame into the first buffer, determining whether the use amount of the first buffer by the frames of a communication type coincident with the communication type of the received frame exceeds a first threshold set to the communication type, and for discarding the received frame if the excess of the use amount is determined; a first calculation unit for calculating the use amount of the first buffer for each communication type in regard to at least two or more time points, and for calculating a numeric value, representing a change in the first buffer use amount, for each communication type; and a setting unit for, based on the numeric value representing the change in the first buffer use amount, calculating a first threshold for each communication type, to set the first threshold to the discard unit.