Method and system for packet exchange

Claim 2

A packet exchange method for use in a packet exchange which receives packets from a plurality of call sources and delivers individual packets to predetermined individual output lines, said method comprising: assigning to individual input packets (S1) information regarding input sequence (IS) of the indivi­dual input packets in each call each time each input packet of said call is received and storing the input sequence information in a storage (2); and delivering said individual input packets sequentially to a predetermined output line (a′, b′, ... or n′) and storing, each time each input packet is delivered to said output line, the input sequence information assigned to each packet in said storage as an output sequence information (OS) in said call of the delivered packets, whereby the status of packets present in said exchange is decided on the basis of said input sequence information and output sequence information.

Claim 3

A packet exchange method for use in a packet exchange system which receives packets from a plurality of call sources and delivers individual packets to predetermined individual output lines, said method comprising: assigning to individual packets (S1) input sequence (IS) of the individual packets in each call each time each packet of said call is received and storing the input sequence in a storage (2); delivering said individual packets sequentially to a predetermined output line (a′, b′, ... or n′) and storing, each time one packet is delivered, the input sequence assigned to said one packet in said storage as an output sequence (OS) in said call of said one packet; detecting, on the basis of the input sequence and output sequence, whether the number of packets destined for each output line and remaining in said exchange system exceeds a predetermined threshold (T1) to cause congestion; and temporarily storing, when congestion is detected for an output line, at least part of input packets scheduled to be destined for said output line which is now subject to rerouting in a rerouting circuit (1x, 120, 5x) having buffer function.

Claim 4

A packet exchange method for use in a packet exchange system which receives packets from a plurality of call sources and delivers individual packets to predetermined individual output lines, said method comprising: assigning to individual packets (S1) input sequence (IS) of the individual packets in each call each time each packet of said call is received and storing the input sequence in a storage (2); delivering said individual packets sequentially to a predetermined output line (a′, b′, ... or n′) and storing, each time one packet is delivered, the input sequence assigned to said one packet in said storage as an output sequence (OS) in said call of said one packet; detecting, on the basis of the input sequence and output sequence, whether the number of packets destined for each output line and remaining in said exchange system exceeds a predetermined threshold (T1) to cause congestion; and temporarily storing, when congestion is detected for an output line, at least part of input packets scheduled to be destined for said output line which is now subject to rerouting in a rerouting circuit (1x, 120, 5x) having buffer function.

Claim 5

A packet exchange method according to Claim 2 further comprising: detecting whether the number (NOP) of packets scheduled to be destined for said output line subject to rerouting which are inputted to said exchange system before execution of rerouting and which remain in said exchange system falls below a predetermined threshold; detecting whether packets belonging to the same call as that of said input packets stored in said rerouting circuit which are inputted to said exchange system before the execution of rerouting are all delivered to said output line subject to rerouting; and delivering said packets stored in said rerouting circuit to said output line subject to rerouting in accordance with results of the above detecting steps.

Claim 6

A packet exchange method according to Claim 3 further comprising: detecting the number of packets present in said rerouting circuit; and releasing said rerouting circuit when results of detection of the number indicate zero.

Claim 7

A packet exchange system for performing packet exchange by setting logical channels, comprising: a packet switch (4); and means (2) for assigning to individual input packets (S1) information indicative of input sequence (IS) of the individual input packets counted in each call and storing the input sequence information, storing, each time each packet is delivered, said input sequence information assigned to an input packet as an output sequence information (OS) in a call to which said delivered packet belongs, and deciding the status of packets of said call which are pre­sent in said exchange on the basis of said stored input seqence information and output sequence informa­tion.

Claim 8

A packet exchange system for performing packet exchange by setting logical channels, comprising: a packet switch (4); and means (2) for assigning to individual input packets (S1) information indicative of input sequence (IS) of the individual input packets counted in each call and storing the input sequence information, storing, each time each packet is delivered, said input sequence information assigned to an input packet as an output sequence information (OS) in a call to which said delivered packet belongs, and deciding the status of packets of said call which are pre­sent in said exchange on the basis of said stored input seqence information and output sequence informa­tion.

Claim 9

A packet exchange system according to Claim 6 wherein said input sequence information and output sequence information are stored in a table (21) which is looked up when an input logical channel number of each input packet is converted into an output logical channel number.

Claim 10

A packet exchange system for looking up a conversion table (21) on the basis of an input logical channel number (IL) possessed by an input packet (S1) and an input line number possessed by an input line (a, b, ... or m) for the input packet, to determine a line number (a′, b′, ... or n′) for which said packet is scheduled to be destined and an output logical channel number (OL) to be assigned to an output packet, said system comprising: a packet switch (4); and means (2, 3) for storing on said conversion table packet input sequence numbers (IS) and output sequence numbers (OS) set in respect of individual calls, looking up said conversion table when a packet of a call is inputted, to assign an output line number and an output logical channel number to said packet, and storing, when said packet is delivered through said packet switch to an output line having said output line number, an input sequence number possessed by said packet in said conversion table as an output sequence number in said call, whereby the number of packets of said call which remain in said exchange is grasped on the basis of the input sequence number and output sequence number on said conversion table.

Claim 11

A packet exchange system for looking up a conversion table (21) on the basis of an input logical channel number (IL) possessed by an input packet (S1) and an input line number possessed by an input line (a, b, ... or m) for the input packet, to determine a line number (a′, b′, ... or n′) for which said packet is scheduled to be destined and an output logical channel number (OL) to be assigned to an output packet, said system comprising: a packet switch (4); and means (2, 3) for storing on said conversion table packet input sequence numbers (IS) and output sequence numbers (OS) set in respect of individual calls, looking up said conversion table when a packet of a call is inputted, to assign an output line number and an output logical channel number to said packet, and storing, when said packet is delivered through said packet switch to an output line having said output line number, an input sequence number possessed by said packet in said conversion table as an output sequence number in said call, whereby the number of packets of said call which remain in said exchange is grasped on the basis of the input sequence number and output sequence number on said conversion table.

Claim 12

A packet exchange system according to Claim 7 further comprising a rerouting circuit (120) having buffer function, and control means (3) for changing the contents of said conversion table when it detects by looking up said conversion table that the number of packets remaining in said exchange which are destined for a specified output line exceeds a predetermined threshold, whereby input packets scheduled to be destined for said specified output line are temporarily stored in said rerouting circuit.

Claim 13

A packet exchange system comprising: means (2) for managing a table including a conversion table (21) which stores output line numbers and output logical channel numbers to be assigned to input packets and packet input sequence numbers and output sequence numbers set for the input packets in respect of individual calls; a plurality of input control means (1a to 1m) respectively connected to respective input lines, each of said plurality of input control means being responsive to an input packet to read out of said conversion table an output line number, an output logical channel number and an input sequence number which are to be assigned to said input packet and assign the read numbers to said input packet; switch means (4), connected to said input control means, for supplying said input packet to an output line possessing the output line number assigned to said input packet; a plurality of output control means (5a to 5m) respectively connected between respective output lines and said switch means, one of said plurality of output control means corresponding to said input packet being operable to access said managing means when said input packet is delivered as an output packet to said output line through said switch means; and means (81, 84, 92b, 90) included in said table managing means and being operable to respond to said accessing to rewrite the output sequence number of said input packet stored in said table in accordance with the input sequence number assigned to said input packet, whereby the number of packets remaining in said exchange is grasped in respect of individual calls on the basis of said input sequence number and output sequence number on said conversion table.

Claim 14

A packet exchange system comprising: means (2) for managing a table including a conversion table (21) which stores output line numbers and output logical channel numbers to be assigned to input packets and packet input sequence numbers and output sequence numbers set for the input packets in respect of individual calls; a plurality of input control means (1a to 1m) respectively connected to respective input lines, each of said plurality of input control means being responsive to an input packet to read out of said conversion table an output line number, an output logical channel number and an input sequence number which are to be assigned to said input packet and assign the read numbers to said input packet; switch means (4), connected to said input control means, for supplying said input packet to an output line possessing the output line number assigned to said input packet; a plurality of output control means (5a to 5m) respectively connected between respective output lines and said switch means, one of said plurality of output control means corresponding to said input packet being operable to access said managing means when said input packet is delivered as an output packet to said output line through said switch means; and means (81, 84, 92b, 90) included in said table managing means and being operable to respond to said accessing to rewrite the output sequence number of said input packet stored in said table in accordance with the input sequence number assigned to said input packet, whereby the number of packets remaining in said exchange is grasped in respect of individual calls on the basis of said input sequence number and output sequence number on said conversion table.

Claim 15

A packet exchange system comprising: means (2) for managing a table including a conversion table (21) which stores output line numbers and output logical channel numbers to be assigned to input packets and packet input sequence numbers and output sequence numbers set for the input packets in respect of individual calls; a plurality of input control means (1a to 1m) respectively connected to respective input lines, each of said plurality of input control means being responsive to an input packet to read out of said conversion table an output line number, an output logical channel number and an input sequence number which are to be assigned to said input packet and assign the read numbers to said input packet; switch means (4), connected to said input control means, for supplying said input packet to an output line possessing the output line number assigned to said input packet; a plurality of output control means (5a to 5m) respectively connected between respective output lines and said switch means, one of said plurality of output control means corresponding to said input packet being operable to access said managing means when said input packet is delivered as an output packet to said output line through said switch means; means (81, 84, 92b, 90) included in said table managing means and being operable to respond to said accessing to rewrite the output sequence number of said input packet stored in said table in accordance with the input sequence number assigned to said input packet; a rerouting circuit (1x, 120, 5x) having buffer function; and means (3, 6) responsive to the number of packets remaining in said exchange in respect of each call and which is known from said input sequence number and output sequence number on said conversion table, for changing said conversion table, when the number of packets remaining in said exchange in respect of a particular output line is detected to be in excess of a predetermined threshold, such that input packets scheduled to be destined for said particular output line are temporarily stored in said rerouting circuit.

Claim 16

A packet exchange system comprising: means (2) for managing a table including a conversion table (21) which stores output line numbers and output logical channel numbers to be assigned to input packets and packet input sequence numbers and output sequence numbers set for the input packets in respect of individual calls; a plurality of input control means (1a to 1m) respectively connected to respective input lines, each of said plurality of input control means being responsive to an input packet to read out of said conversion table an output line number, an output logical channel number and an input sequence number which are to be assigned to said input packet and assign the read numbers to said input packet; switch means (4), connected to said input control means, for supplying said input packet to an output line possessing the output line number assigned to said input packet; a plurality of output control means (5a to 5m) respectively connected between respective output lines and said switch means, one of said plurality of output control means corresponding to said input packet being operable to access said managing means when said input packet is delivered as an output packet to said output line through said switch means; means (81, 84, 92b, 90) included in said table managing means and being operable to respond to said accessing to rewrite the output sequence number of said input packet stored in said table in accordance with the input sequence number assigned to said input packet; a rerouting circuit (1x, 120, 5x) having buffer function; and means (3, 6) responsive to the number of packets remaining in said exchange in respect of each call and which is known from said input sequence number and output sequence number on said conversion table, for changing said conversion table, when the number of packets remaining in said exchange in respect of a particular output line is detected to be in excess of a predetermined threshold, such that input packets scheduled to be destined for said particular output line are temporarily stored in said rerouting circuit.

Claim 17

A packet exchange system according to Claim 10 wherein said rerouting circuit comprises additional output control means (5n) having its input connected to said switch means and receiving a packet rerouted through said switch means, additional input control means (1x) having its input connected to the output of said additional output control means and receiving said input packet from said additional output control means, a buffer memory (120) having its input connected to the output of said additional input control means, further output control means (5x) having its input connected to the output of said buffer memory and receiving a packet from said buffer memory, and further input control means (lm) having its input connected to the output of said further output control means and its output connected to said switch means and delivering a packet from said further output control means to said switch means.

Claim 18

A packet exchange system according to Claim 11 wherein said managing means further comprises first (21b), second (21c) and third (21d) conversion tables adapted to supply an input packet scheduled to be destined for said particular output line to said rerouting circuit, said first table being operable to store a line number and an output logical channel number which are to be assigned to said input packet and are possessed by said additional output control means as well as a packet input sequence number and a packet output sequence number which are set for said input packet in respect of the corresponding call, said second table being operable to store an output line number and an output logical channel number which are to be assigned to said packet inputted to said additional input control means and are possessed by said further output control means as well as a packet input sequence number and a packet output sequence number which are set for said packet in respect of the corresponding call, and said third table being operable to store an output line number of said particular output line and an output logical channel number which are to be assigned to said packet inputted to said further input control means as well as a packet input sequence number and an output sequence number which are set for said packet in respect of the corre­sponding call.

Claim 19

A packet exchange system according to Claim 12 wherein said changing means comprises means operable, when two conditions are both satisfied wherein the number (NOP) of packets which are scheduled to be destined for an output line subject to rerouting and which are inputted to said exchange system before execution of rerouting and still remain in said exchange falls below a predetermined threshold (T3) and wherein packets belonging to the same call as that of packets stored in said rerouting circuit and which are inputted to said exchange system before the execution of rerouting are all delivered, to perform control such that said packets stored in said buffer memory are permitted to be delivered to said output line subject to rerouting.

Claim 20

A packet exchange system according to Claim 12 wherein said changing means comprises means for detecting, on the basis of said packet input sequence number and output sequence number on each of said first, second and third tables, whether the number of packets remaining on said rerouting circuit is zero and releasing said rerouting circuit when detection results indicate zero.