Network traffic control method in voip

PURPOSE: A network traffic control method in VoIP(Voice over Internet Protocol) is provided to prevent an overload of a network by controlling a VAD(Voice Activity Detection) or a frame size according to a network traffic. CONSTITUTION: A controller checks an RTP header of transmitted and received data packet for a certain time period and calculates a network traffic measurement value(S100). If the network traffic measurement value is judged to belong to a first reference range(S110), the controller maximizes the frame size(S115). If the network traffic measurement value is judged to belong to a second reference range(S120), the controller controls the frame size to be a middle value(S125). If the network traffic measurement value is judged to belong to a third reference range, the controller minimizes the frame size(S130).