Patent ID: 6804198
Filing Date: 2004-10-12
Classification: H04L

Abstract:
An ATM (Asynchronous Transfer Mode) cell buffer system for buffering ATM cells in various network nodes forming an ATM network, comprising:congestion control means for controlling congestion of the ATM cells; and control counter means for counting the number of ATM cells supplied from an ATM cell buffer, in every predetermined period, for every VC (Virtual Channel) queue, within said congestion control means, wherein said control counter means comprises: first counting means for counting the number of ATM cells supplied from the ATM cell buffer in the present predetermined period as a first count value, and second counting means for counting the number obtained by subtracting the number of ATM cells stored in the ATM cell buffer in the present predetermined period from the first count value in the previous predetermined period, as a second count value, wherein said control counter means sets the first count value as the minimum output bandwidth, and decides whether the ATM cell is stored in the ATM cell buffer or abandoned, according to the second count value, and said congestion control means judges congestion of the ATM cell buffer by three types of states: non-congested state, low-congested state, and high-congested state for every VC queue and deciding the count value of said control counter means as minimum output bandwidth for deciding the number of ATM cells to be stored in the next predetermined period, for every connection, wherein in the case of the non-congested state, said congestion control means stores an ATM cell indifferently to the second count value of said control counter means, in the case of the low-congested state, said congestion control means abandons an ATM cell only when there is a stored cell within a VC queue and an ATM cell is supplied beyond the minimum output bandwidth, and in the case of the high-congested state, the congestion control means always abandons an ATM cell.