Packet congestion control method and packet switching equipment

Claim 2

A packet switching equipment comprising: a plurality of input lines (301); a plurality of output lines (303); switch means (200) for selectively outputting to said output line an input packet from said input line; means (223) for detecting a congestion of packets in association with each said output line; and means (100) for returning a packet produced by adding a congestion indicator to an input packet associated with an output line on which a congestion is detected by said detect means to an output line as a transmission source of said packet, said packet being returned as a congestion notice packet.

Claim 3

A packet switching equipment according to Claim 1, wherein said switch means includes: buffer memory means (219) for storing therein packets inputted from said input lines; and counter means (218) for counting the number of the packets stored in said buffer memory means for each of said output lines and said congestion detect means includes means for comparing a count value developed by said counter means with a predetermined threshold value.

Claim 4

A packet switching equipment comprising: a plurality of input lines (301) and a plurality of output lines (303) mutually paired with each other; a plurality of line interfaces (100) disposed for each said pair of the input and output lines; switch means (200) for achieving a switch operation of packets between said line interfaces; means (223) for detecting a packet congestion state in association with each said output line in said switch means; and means (225) for adding congestion information to a packet to be outputted to an output line for which a congestion is detected by said detect means, each of said interfaces including means (130, 150) operative when a packet to which the congestion information is added is received for producing a congestion notice packet to an equipment of a transmission source of the packet.

Claim 5

A packet switching equipment comprising: a plurality of input lines (301) and a plurality of output lines (303) mutually paired with each other; a plurality of line interfaces (100) disposed for each said pair of the input and output lines; switch means (200) for achieving a switch operation of packets between said line interfaces; means (223) for detecting a packet congestion state in association with each said output line in said switch means; and means (225) for adding congestion information to a packet to be outputted to an output line for which a congestion is detected by said detect means, each of said interfaces including means (130, 150) operative when a packet to which the congestion information is added is received for producing a congestion notice packet to an equipment of a transmission source of the packet.

Claim 6

A packet switching equipment according to Claim 3, wherein said congestion notice packet produce means includes: packet branch means (181) disposed between said output lines and said switch means; and packet insert means (130) disposed between said input lines and said switch means, wherein when said packet branch means receives a packet having the congestion information from said switch means, the congestion notice packet is produced so as to be returned via said packet insert means to said switch means.

Claim 7

A packet switching equipment comprising: a plurality of input lines (30) and a plurality of output lines (303) mutually paired with each other; a plurality of line interfaces (100) disposed for each of the pairs of the input and output lines; switch means (200) for achieving a switch operation of packets between said line interfaces; and means (223) for detecting a packet congestion occurring in association with each of said output lines in said switch means, each of said line interfaces including means (130, 150, 170) responsive to a control signal from said congestion detect means for returning to the output line a congestion notice packet created by adding a congestion indicator to an input packet from the input line.

Claim 8

A packet switching equipment comprising: a plurality of input lines (30) and a plurality of output lines (303) mutually paired with each other; a plurality of line interfaces (100) disposed for each of the pairs of the input and output lines; switch means (200) for achieving a switch operation of packets between said line interfaces; and means (223) for detecting a packet congestion occurring in association with each of said output lines in said switch means, each of said line interfaces including means (130, 150, 170) responsive to a control signal from said congestion detect means for returning to the output line a congestion notice packet created by adding a congestion indicator to an input packet from the input line.

Claim 9

A packet congestion control method in a packet switching system including switch means (200) housing therein a plurality of pairs of input lines (301) and output lines (303) respectively connected to a communication equipment (50) and to other packet switching equipment (60) such that a packet inputted from either one of said input lines is temporarily stored in a buffer memory (261) so as to thereafter output the packet to one of said output lines associated with a destination communication equipment of the packet and means (223) for monitoring a congestion state of a packet in the switch means for each of said output lines comprising: a step of storing in a buffer memory of the switch means a packet inputted from each said input line in association with an output line onto which the packet is to be outputted; a step of monitoring by the monitor means, for each of said output lines, the number of packets existing in the buffer memory to be outputted to said each output line so as to generate a state signal indicating whether or not there occurs a packet congestion; a step of sequentially reading a packet to be outputted to said each output line from the buffer memory in an order of the output lines so as to transmit the packet to the output line; and a step of producing when the state signal indicates an occurrence of a congestion or a cease of a congestion on either one of the output lines, a conges­tion control packet in a form in which a congestion state indictor is added to the packet to be outputted to the output line so as to return the packet to an output line paired with the input line of the packet, whereby the communication equipment having received the congestion control packet alters a transmission mode of a subsequent packet depending on a content of the congestion state indicator included in the congestion control packet.

Claim 10

A packet congestion control method in a packet switching system including switch means (200) housing therein a plurality of pairs of input lines (301) and output lines (303) respectively connected to a communication equipment (50) and to other packet switching equipment (60) such that a packet inputted from either one of said input lines is temporarily stored in a buffer memory (261) so as to thereafter output the packet to one of said output lines associated with a destination communication equipment of the packet and means (223) for monitoring a congestion state of a packet in the switch means for each of said output lines comprising: a step of storing in a buffer memory of the switch means a packet inputted from each said input line in association with an output line onto which the packet is to be outputted; a step of monitoring by the monitor means, for each of said output lines, the number of packets existing in the buffer memory to be outputted to said each output line so as to generate a state signal indicating whether or not there occurs a packet congestion; a step of sequentially reading a packet to be outputted to said each output line from the buffer memory in an order of the output lines so as to transmit the packet to the output line; and a step of producing when the state signal indicates an occurrence of a congestion or a cease of a congestion on either one of the output lines, a conges­tion control packet in a form in which a congestion state indictor is added to the packet to be outputted to the output line so as to return the packet to an output line paired with the input line of the packet, whereby the communication equipment having received the congestion control packet alters a transmission mode of a subsequent packet depending on a content of the congestion state indicator included in the congestion control packet.

Claim 11

A method according to Claim 6, wherein said packet switching equipment includes a plurality of line interface means (100) disposed in association with said pairs of input and output lines, the generation and the return of the conges­tion control packet being achieved by the line interface means on an input side of a packet.

Claim 12

A method according to Claim 6, wherein said packet switching equipment includes a plurality of line interface means (100) disposed in association with said pairs of input and output lines, the generation and the return of the conges­tion control packet being achieved by the line interface means on an output side of the packet such that the congestion control packet is outputted from the interface means on the output side via the switch means to one of the output lines.

Claim 13

A method according to Claim 8, wherein each said interface means includes a step of converting a first packet format effective on the input line side and on the output line side into a second packet format effective in the packet switching equipment.

Claim 14

A method according to Claim 6, wherein the communication equipment having received the congestion control packet operates (FIG. 15, 655), when a congestion state indicator contained in the congestion control packet indicates an occurrence of a congestion, in a packet transmission mode in which an amount of packets to be transmitted is reduced, and operates (FIG. 15, 657), when a congestion state indicator indicates a cease of a congestion for operating in a packet trans­mission mode, in which an amount of packets to be transmitted is increased.

Claim 15

A method according to Claim 6, wherein the communication equipment having received the congestion control packet includes interrupts (FIG. 15, 659), when a congestion state indicator contained in the congestion control packet indicates an occurrence of a congestion, a transmission of a data packet and for transmitting a polling packet at a fixed interval of time, and said packet switching equipment produces, when a congestion ceases, a congestion control packet in a form in which the congestion state indicator is added to the polling packet transmitted from the communication equipment so as to return the packet to the communication equipment.