EP0853441A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Switch control circuit and switch control method of ATM switchboard
Assignee: Juniper Networks Inc
•
Filing: 1997-11-13
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Granted: —
•
Expires: 2017-11-13
Abstract
Abstract Traffic control for controlling the occurrence of congestion in an ATM switchboard and assuring the throughput of VCs using the same output port. A buffer occupancy value measuring section measures the queue length of each output port buffer and stores the data in a buffer occupancy value table. A back-pressure outputting section outputs a transmission restart signal when a queue length in the buffer occupancy table is equal to or less than a first threshold, a transmission control signal when the queue length is between the first threshold and a second threshold, and a transmission stop signal when the queue length is equal to or more than the second threshold as the appropriate back pressure signal. A cell transmission control section transmits an ATM cell without comparing the cell transmission time with the present time if the instruction of a back pressure signal corresponding to a destination port indicates "restart" and transmits an ATM cell only if the transmission time is earlier than the present time if the instruction indicates "control".
Inventors
- 👤 Masayuki Shinohara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 12:14
CPC Classifications
H; H04; H04L; H04L49/00; H04L49/10; H04L49/104; H04L49/105; H04L12/00; H04L12/54; H04L12/56; H04L12/5601; H04L12/5602; H04L49/30; H04L49/3081; H04L49/50; H04L49/501; H04L49/503; H04L49/505; H04L49/506; H04Q; H04Q11/00; H04Q11/04; H04Q11/0428; H04Q11/0478; H04Q3/00; H04Q3/64; H04Q3/645; H04L2012/5629; H04L2012/5631; H04L2012/5632; H04L2012/5635; H04L2012/5636; H04L2012/5678; H04L2012/5681; H04L49/20; H04L49/55; H04L49/552; H04Q2213/00; H04Q2213/13103; H04Q2213/13164; H04Q2213/13166; H04Q2213/1329
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
171 words
A switch control circuit of an ATM switchboard for
switching ATM cells transferred in an asynchronous mode
between an input port and an output port, said circuit
comprising an input port buffer and an output port buffer
provided correspondingly to said input port and said output
port respectively to perform ATM cell exchange between said
input port and said output port; a back-pressure function for
outputting any one of a transmission restart signal,
transmission stop signal, and transmission control signal in
accordance with said occupancy value of said output port
buffer in order to prevent cells from being unused by said
output port buffer; and cell transmission control means
to transmit said ATM cells at a preset
first rate to an output port,
when said transmission restart signal is input from said
back-pressure function corresponding to said output port
and to transmit said ATM cells at a preset second rate
to an output port when said transmission
control signal is input from said back pressure function
corresponding to said output port.
Claim 2
Dependent Claim
40 words
The switch control circuit according to claim 1,
wherein said back pressure function is constituted so as to
output any one of said transmission restart signal, said
transmission stop signal, and said transmission control
signal correspondingly to said output port.
Claim 3
Dependent Claim
85 words
The switch control circuit according to claim 1,
wherein said back pressure function is constituted so as to
output said transmission restart signal when the occupancy
value of said output port buffer is less than a preset first
threshold, said transmission control signal when the
occupancy value of said output port buffer is between said
first threshold and a preset second threshold, and said
transmission stop signal when the occupancy value of said
output port buffer is equal to or more than said second
threshold.
Claim 4
Dependent Claim
70 words
The switch control circuit according to claim 1,
wherein said cell transmission control means includes
comparison means for comparing the present time with a
scheduled transmission time computed in accordance with said
second rate when transmitting said ATM cells at said second
rate and means for performing control by said comparison means
so as to transmit said ATM cells when said scheduled
transmission time is earlier than said present time.
Claim 5
Dependent Claim
57 words
The switch control circuit according to claim 1,
wherein said cell transmission control means includes means
for performing control so as to transmit said ATM cells at
the maximum rate in order of scheduled transmission time
computed in accordance with said second rate independently
of the present time when transmitting said ATM cells at said
first rate.
Claim 6
Dependent Claim
28 words
The switch control circuit according to claim 1,
wherein said cell transmission control means includes time
computing means for computing a scheduled transmission time
of an ATM cell.
Claim 7
Dependent Claim
64 words
The switch control circuit according to claim 1,
wherein said cell transmission control means has a list in
which said ATM cells to be transmitted are arranged in order
of scheduled transmission time and in which said cell transmission
control controls the transmission of an ATM cell at the head of the list
in accordance with a signal obtained from said back pressure function.
Claim 8
Dependent Claim
68 words
The switch control circuit according to claim 3,
wherein said back pressure function first checks whether
said output port buffer has an occupancy value
less than said first threshold, then checks whether
said output port buffer has an occupancy value between said
first threshold and said second threshold, and finally checks
whether said output port buffer has an occupancy
value equal to or more than said second threshold.
Claim 9
Dependent Claim
74 words
The switch control circuit according to claim 8,
wherein said back pressure function outputs a transmission
stop signal corresponding to said output port buffer to said
cell transmission control means when said output port
buffer has an occupancy value equal to or more than the
said second threshold and thereafter, outputs any one of said
transmission restart signal, said transmission stop signal,
and said transmission control signal corresponding to each
output port buffer again.
Claim 10
Dependent Claim
56 words
The switch control circuit according to claim 8,
wherein said back pressure function outputs any one of said
transmission restart signal, said transmission stop signal,
and said transmission control signal corresponding to each
output port buffer again when not one of said output buffers
has an occupancy value equal to or more than said second
threshold.
Claim 11
Dependent Claim
62 words
The switch control circuit according to claim 7,
wherein said transmission control means stop the transmission
of said ATM cells and controls the transmission of an ATM cell
next located in said list in accordance with a signal obtained
from said back pressure function when said transmission stop
signal is input to said cell transmission control means by
said back pressure function.
Claim 12
Dependent Claim
73 words
The switch control circuit according to claim 7,
wherein said cell transmission control means decides that a case
in which said transmission restart signal, said transmission
stop signal, or said transmission control signal is not input
to said cell transmission control means by said back pressure
function is an error and controls the transmission of the
next ATM cell in said list in accordance with a signal
obtained from said back pressure function.
Claim 13
Dependent Claim
131 words
A switch control method for an ATM switchboard for
switching an ATM cell transferred in an asynchronous mode
between an input port and an output port, the method comprising
the first step of outputting any one of a transmission restart
signal, transmission stop signal, and transmission control
signal in accordance with the occupancy value of said output
port buffer in order to prevent cells in said output port
buffer from being discarded and the second step of
performing control so as to transmit said ATM cell at a
preset first rate to an output port when said transmission
restart signal is input in said first step and transmitting
said ATM cell to an output
port at a preset second rate when said transmission control signal is input in
said first step.
Claim 14
Dependent Claim
128 words
A traffic control method for controlling congestion in an ATM
switchboard, comprising: measuring the queue length of each output port buffer and storing the
buffer occupancy value in a buffer occupancy table; outputting a back-pressure control signal wherein said back-pressure
control signal is a transmission restart signal when the buffer occupancy value
is equal to or less than a threshold, is a transmission control signal when the
buffer value is between the first threshold and a second threshold, and is a
transmission stop signal when the buffer value exceeds a second threshold
value; transmitting a cell without examining its transmission scheduled time
if the back-pressure signal indicates "restart" for the destination port; and transmitting a cell only at its scheduled transmission time if the back-pressure
signal indicates "control".
Claim 15
Dependent Claim
84 words
The switch control method according to claim 13, wherein said
first step is constituted so as to output said transmission restart signal when
the occupancy value of said output port buffer is less than a preset first
threshold, said transmission control signal when the occupancy value of said
output port buffer is between said first threshold and a preset second
threshold, and said transmission stop signal when the occupancy value of said
output port buffer is equal to or more than said second threshold.
Claim 16
Dependent Claim
63 words
The switch control method according to claim 13, wherein said
second step includes comparing the present time with a schedule transmission
time computed in accordance with said second rate when transmitting said
ATM cells at said second rate and performing control so as to transmit said
ATM cells when said scheduled
transmission time is earlier than said present time in said
third step.
Claim 17
Dependent Claim
46 words
The switch control method according to claim 13,
wherein said second step includes
transmitting said ATM cells at the highest rate of
scheduled transmission time computed in accordance with said
second rate independently of the present time when
transmitting said ATM cells at said first rate.
Claim 18
Dependent Claim
32 words
The switch control method according to claim 13,
wherein said second step includes
transmitting said ATM cells and thereafter computing the
scheduled transmission time of the next ATM cell to be
transmitted.
Claim 19
Dependent Claim
59 words
The switch control method according to claim 13,
wherein said second step includes
generating a list by arranging said ATM cells to be transmitted
in order of scheduled transmission time and the eighth step
of controlling the transmission of an ATM cell located at the
head of the list in accordance with a signal obtained from
said first step.
Claim 20
Dependent Claim
68 words
The switch control method according to claim 13,
wherein said first step first includes checking whether said
output port buffer has an occupancy value less than said
first threshold, then checks whether said output port
buffer has an occupancy value between said first threshold
and said second threshold, and finally checks whether
said output port buffer has an occupancy value equal
to or more than said second threshold.
Claim 21
Dependent Claim
68 words
The switch control method according to claim 20,
wherein said first step includes outputting a transmission stop
signal corresponding to said output port buffer when said
output port buffer has - an occupancy value equal to or more
than said second threshold and thereafter, outputs any one
of said transmission restart signal, said transmission stop
signal, and said transmission control signal corresponding
to each output port buffer again.
Claim 22
Dependent Claim
56 words
The switch control method according to claim 20,
wherein said first step includes outputting again any one of said
transmission restart signal, said transmission stop signal,
and said transmission control signal corresponding to each
output port buffer when not one of said output buffers has
an occupancy value equal to or more than said second threshold.
Claim 23
Dependent Claim
50 words
The switch control method according to claim 19,
wherein said second step includes stopping the transmission of said
ATM cells when said transmission stop signal is input and controls
the transmission of an ATM cell next located in said list in accordance with
a signal obtained from said first step.
Claim 24
Dependent Claim
59 words
The switch control method according to claim 19, wherein said
second step decides that a case in which said transmission restart signal, said
transmission stop signal, or said transmission control signal is not input is an
error and controls the transmission of the next ATM cell in said list in
accordance with a signal obtained from said first step.
References Cited (Backward Citations)
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