| 摘要 |
PURPOSE: An apparatus and a method for controlling a UBR(Unspecified Bit Rate) traffic in an ATM exchange are provided to maximize UBR traffic efficiency by confirming traffic congestion in an ATM switch by using the buffer threshold of an egress subscriber block and the PTI(Payload Type Identifier) field of a traffic cell when a UBR band is decreased and by equally increasing UBR bands according to the traffic load of a cell trafficked from the ATM switch when UBR traffics are increased. CONSTITUTION: User cells, control cells, traffic load signals, and traffic state signals are periodically inputted to a traffic state judgment part from a PTI processing part, a load measurement part, and an egress buffer part(S401). The traffic state judgment part confirms the PTI field setting values of the user cell and control cell inputted through the PTI processing part at a specific period(S402). In case that the PTI setting values are set to '1', the traffic state judgment part checks whether the number of user cells stored in the egress buffer part exceeds the minimum buffer threshold, based on the traffic state signal inputted from the egress buffer part(S403). In case that the number of the stored user cells exceeds the minimum buffer threshold, the traffic state judgment part decreases the present UBR band to a UBR available band(S404).
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