Packet communication system and method of controlling same

Claim 2

A packet communication system which produces packets of information from communication information received from one of a plurality of types of sources, wherein the packets include a portion of the communication information and control information which includes instantaneousness priority data representative of the degree of instantaneousness required to transmit the communication information, and discard priority data representative of the degree to which a portion of the communication data may be discarded without significantly effecting the quality of the transmission of the communication information, the system comprising: a plurality of buffers provided for temporarily storing said packets, wherein each buffer stores packets having instantaneousness priority data which is different from the instantaneousness priority data of packets stored in the other buffers; input control means for receiving the packets and writing the received packets into a corresponding one of the plurality of buffers in accordance with the instantaneousness priority data of the received packets; first counting means for counting the number of packets currently stored in each buffer on the basis of the numbers of packets written in and read out from each buffer; and output control means for respectively controlling a frequency at which the packets are to be read from each buffer in accordance with the number of packets stored in each buffer.

Claim 3

The packet communication system of claim 1, further comprising: comparing means for comparing the number of packets stored in each buffer with a plurality of first threshold values set for each of the respective buffers, wherein said output control means further controls the frequency at which the packets are read from each buffer in accordance with the output of said comparing means.

Claim 4

The packet communication system of claim 2, wherein said output control means further controls the frequency at which the packets are read from each buffer in accordance with the output of said comparing means and output requests from the buffers.

Claim 5

The packet communication system of claim 2, further comprising: output control counter means for repetitively outputting a count value which is incremented by a predetermined value in synchronism with a predetermined clock signal, wherein said output control means further controls the frequency at which the packets are read from each buffer in accordance with the output of said comparing means, the output requests from the buffers, and a count value of said output control counter means.

Claim 6

The packet communication system of claim 4, wherein said output control means includes a memory including a plurality of addressable memory planes corresponding in number with the number of possible combinations of the outputs of said comparing means and the output requests from the respective buffers such that each of the memory planes are addressed by a particular combination of outputs from said comparing means and output requests from the respective buffers, each memory plane causes an output acknowledge signal to be output to a selected one of the buffers each time the count value of said output control counter means is incremented, and the output acknowledge signal permits said output control means to read a packet from the selected buffer.

Claim 7

The packet communication system of claim 1, further comprising: second counting means for counting the total number of packets stored in all of the plurality of buffers on the basis of the numbers of packets written in and read out from the plurality of buffers, wherein said input control means controls writing of packets into the respective buffers in accordance with the total number of packets stored in the plurality of buffers.

Claim 8

The packet communication system of claim 6, further comprising: comparing means for comparing the total number of packets stored in the plurality of buffers with a plurality of second threshold values set in accordance with the discard priority data, wherein said input control means controls writing of packets into the respective buffers in accordance with a comparison result of said comparing means.

Claim 9

The packet communication system of claim 7, wherein said input control means controls writing of packets into the respective buffers in accordance with the comparison result of said comparing means and input requests for the buffers.

Claim 10

The packet communication system of claim 8, wherein said input control means includes a memory for storing a plurality of input acknowledge signals which permit writing of packets into the respective buffers, wherein each of the input acknowledge signals is addressable with respect to the comparison result of said comparing means, the input requests, and the discard priority data, and wherein the input control means controls writing of packets into the respective buffers in accordance with the input acknowledge signal read out from said memory.

Claim 11

A packet communication system which produces packets of information from communication information received from one of a plurality of types of sources, wherein the packets include a portion of the communication information and control information which includes instantaneousness priority data representative of the degree of instantaneousness required to transmit the communication information, and discard priority data representative of the degree to which a portion of the communication data may be discarded without significantly effecting the quality of the transmission of the communication information, the system comprising: a plurality of buffers provided for temporarily storing said packets, wherein each buffer stores packets having instantaneousness priority data which is different from the instantaneousness priority data of packets stored in the other buffers; counting means for counting the number of packets stored in each buffers and the total number of packets stored in all of the plurality of buffers on the basis of the numbers of packets written in and read out from each of the buffers; comparator means for comparing the numbers of packets stored in the respective buffers with a plurality of first threshold values which are set in association with the plurality of buffers to output an output control signal indicating that the number of packets stored in each buffer respectively exceeds each of the plurality of first threshold values, and for comparing the total number of packets stored in the plurality of buffers with a plurality of second threshold values which are set in association with the discard priority data to output a plurality of acknowledge inhibiting signals indicating that the total number of packets stored in the respective buffers respectively exceeds each of the plurality of second threshold values; output control counter means for repetitively outputting a count value which is incremented by a predetermined value in synchronism with a predetermined clock signal, input control means for controlling writing of packets into the respective buffers in accordance with the acknowledge inhibiting signals output from said comparator means, input requests for the buffers, the discard priority data, and the instantaneousness priority data; and output control means for controlling a frequency at which the packets are read from each buffer in accordance with the output control signal output from said comparator means, the output requests from the respective buffers, and count values of said output control counter means.

Claim 12

A packet communication system which produces packets of information from communication information received from one of a plurality of types of sources, wherein the packets include a portion of the communication information and control information which includes instantaneousness priority data representative of the degree of instantaneousness required to transmit the communication information, and discard priority data representative of the degree to which a portion of the communication data may be discarded without significantly effecting the quality of the transmission of the communication information, the system comprising: a plurality of buffers provided for temporarily storing said packets, wherein each buffer stores packets having instantaneousness priority data which is different from the instantaneousness priority data of packets stored in the other buffers; counting means for counting the number of packets stored in each buffers and the total number of packets stored in all of the plurality of buffers on the basis of the numbers of packets written in and read out from each of the buffers; comparator means for comparing the numbers of packets stored in the respective buffers with a plurality of first threshold values which are set in association with the plurality of buffers to output an output control signal indicating that the number of packets stored in each buffer respectively exceeds each of the plurality of first threshold values, and for comparing the total number of packets stored in the plurality of buffers with a plurality of second threshold values which are set in association with the discard priority data to output a plurality of acknowledge inhibiting signals indicating that the total number of packets stored in the respective buffers respectively exceeds each of the plurality of second threshold values; output control counter means for repetitively outputting a count value which is incremented by a predetermined value in synchronism with a predetermined clock signal, input control means for controlling writing of packets into the respective buffers in accordance with the acknowledge inhibiting signals output from said comparator means, input requests for the buffers, the discard priority data, and the instantaneousness priority data; and output control means for controlling a frequency at which the packets are read from each buffer in accordance with the output control signal output from said comparator means, the output requests from the respective buffers, and count values of said output control counter means.