U.S. patent application number 09/040854 was filed with the patent office on 2002-05-16 for exchange for changing a route of a transmission path to bypass a malfunctioning switch.
Invention is credited to IINO, TOSHIYUKI, SHIRAI, HIROAKI.
Application Number | 20020057647 09/040854 |
Document ID | / |
Family ID | 17565266 |
Filed Date | 2002-05-16 |
United States Patent
Application |
20020057647 |
Kind Code |
A1 |
IINO, TOSHIYUKI ; et
al. |
May 16, 2002 |
EXCHANGE FOR CHANGING A ROUTE OF A TRANSMISSION PATH TO BYPASS A
MALFUNCTIONING SWITCH
Abstract
An exchange changes a route of a transmission path to bypass a
malfunctioning switch. The transmission path is formed in a switch
network including a plurality of switches for transmitting
communication information. The switch network is provided with a
plurality of inputs and a plurality of outputs so that the
transmission path is formed between one of the inputs and one of
the outputs by routing the switches in the switch network. A
malfunctioning switch detecting unit detects a location of the
malfunctioning switch in the switch network. The route of the
transmission path is changed by switching one of the inputs and
outputs connected to the transmission path based on predetermined
routing information which indicates a route to bypass the
malfunctioning switch in relation to the inputs or the outputs of
the switch network.
Inventors: |
IINO, TOSHIYUKI;
(KAWASAKI-SHI, JP) ; SHIRAI, HIROAKI;
(KAWASAKI-SHI, JP) |
Correspondence
Address: |
HELFGOTT & KARAS
60TH FLOOR
EMPIRE STATE BUILDING
NEW YORK
NY
101180110
|
Family ID: |
17565266 |
Appl. No.: |
09/040854 |
Filed: |
March 18, 1998 |
Current U.S.
Class: |
370/217 |
Current CPC
Class: |
H04L 49/30 20130101;
H04L 49/555 20130101; H04L 49/1553 20130101; H04L 49/256 20130101;
H04L 49/101 20130101; H04L 2012/5627 20130101; H04L 49/15 20130101;
H04L 49/557 20130101; H04L 49/254 20130101 |
Class at
Publication: |
370/217 |
International
Class: |
G01R 031/08 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 8, 1997 |
JP |
9-276134 |
Claims
What is claimed is:
1. An exchange setting a transmission path for transmitting
communication information through a switch network comprising a
plurality of switches, said switch network provided with a
plurality of inputs and a plurality of outputs so that the
transmission path is formed between one of the inputs and one of
the outputs by routing the switches in said switch network, said
exchange changing a route of the transmission path when a
malfunction occurs in one of the switches included in the
transmission path so as to bypass the malfunctioning switch, said
exchange comprising: a malfunctioning switch detecting unit
detecting a location of the malfunctioning switch in said switch
network; and changing means for changing the route of the
transmission path by switching one of the inputs and outputs
connected to the transmission path based on predetermined routing
information so as to bypass the malfunctioning switch.
2. The exchange as claimed in claim 1, wherein said changing means
comprises: a storing unit which stores table information indicating
a plurality of routes each of which bypasses one of the switches in
said switch network, each of the routes being indicated in relation
to one of the inputs and outputs of the switch network; and a
selecting unit selecting one of the routes indicated in said table
information so as to change the route of the transmission path to
bypass the malfunctioning switch.
3. The exchange as claimed in claim 2, wherein said changing means
further comprises: an input switching unit switching the input of
said switch network; an output switching means switching the output
of said switch network; and input and output selecting means for
selecting one of said input switching unit and said output
switching unit so that said changing means changes the route of the
transmission path by the selected one of said input switching unit
and said output switching unit.
4. The exchange as claimed in claim 3, wherein said input and
output selecting means selects said input switching unit when the
malfunctioning switch is one of the switches directly connected to
said input switching unit.
5. The exchange as claimed in claim 3, wherein said input and
output selecting means selects said output switching unit when the
malfunctioning switch is one of the switches directly connected to
said output switching unit.
6. The exchange as claimed in claim 3, wherein said input and
output selecting means selects said input switching unit when the
malfunctioning switch is one of the switches other than the
switches directly connected to one of said input switching unit and
said output switching unit.
7. The exchange as claimed in claim 3, wherein said input and
output selecting means selects said output switching unit when the
malfunctioning switch is one of the switches other than the
switches directly connected to one of said input switching unit and
said output switching unit.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to an exchange and,
more particularly, to an exchange which changes a route of a
transmission path, when a malfunction occurs in one of a plurality
of switches, so as to bypass the malfunctioning switch.
[0003] In an exchange or a transmission apparatus which
communicates information including audio data and image data, a
switch network is provided with a plurality of inputs and outputs
so that any one of the inputs can be connected to any one of the
outputs so as to arbitrarily change a route of a communication path
formed in the switch network.
[0004] 2. Description of the Related Art
[0005] A description will now be given of a conventional method for
avoiding influence of a malfunction occurring in one of a plurality
of switches which constitute a switch network in an exchange.
[0006] FIGS. 1, 2 and 3 show a first, second and third conventional
exchange, respectively.
[0007] The first conventional exchange shown in FIG.1 comprises a
working switch network 101, a spare switch network 102 having the
same structure as the working switch network 101, an input
switching unit 103 and an output switching unit 104. The working
switch network 101 comprises a plurality of switches, and has a
plurality of inputs and a plurality of outputs. The input switching
unit 103 and the output switching unit 104 change a transmission
path formed through the exchange so that the transmission path is
formed in the spare switch network 102 instead of the working
switch network 101 when a malfunction occurs in one of the switches
in the working switch network 101 which is actually being used.
[0008] When a malfunction occurs in one of the switches
constituting the working switch network 101, the first conventional
exchange bypasses the malfunctioning switch by switching the
actually used switch network from the working switch network 101 to
the spare switch network 102. This switching operation is performed
by the input switching unit 103 and the output switching unit 104.
Transmission paths formed after the switching operation are also
formed in the spare switch network 102.
[0009] The second conventional exchange shown in FIG.2 comprises a
switch network 111, an input switching unit 112, an output
switching unit 113 and a header changing table circuit 114. The
switch network 111 comprises a plurality of switches and a
plurality of spare switches reserved for spare use. The switch
network 111 has a plurality of inputs and a plurality of outputs,
and also has a plurality of spare inputs and a plurality of spare
outputs. The input switching unit 112 and the output switching unit
113 change a route of a transmission path formed through the
exchange so that the transmission path is formed between one of the
spare inputs and one of the spare outputs when a malfunction occurs
in one of the switches included in the transmission path in the
switch network. The header changing table circuit 114 changes input
address information, which is included in communication information
to be transmitted, to input address information of one of the spare
inputs.
[0010] When a malfunction occurs in one of the switches in the
switch network 111, the second conventional exchange bypasses the
malfunctioning switch by changing a route of the transmission path
including the malfunctioning switch to a route formed between one
of the spare switches and one of the spare inputs.
[0011] The third conventional exchange shown in FIG.3 comprises a
switch network 121 including a plurality of switches. The switch
network 121 has a plurality of inputs and a plurality of outputs.
When a malfunction occurs in one of the switches constituting the
switch network 121, the malfunctioning switch is detected so that a
transmission path routing the malfunctioning switch is changed to a
transmission path routing a spare switch instead of the
malfunctioning switch.
[0012] However, each of the above-mentioned conventional exchanges
has the following problems.
[0013] In the first conventional exchange, since a detection of the
malfunctioning switch in the actually used working switch network
101 is not performed, a transmission path routing the
malfunctioning switch cannot be distinguished. Thus, all
transmission paths including normal transmission paths must be
switched to transmission paths formed in the spare switch network
102 when a malfunction occurs in one of the switches in the working
switch network 101.
[0014] In the first, second and third conventional exchanges, since
the spare switch network or the spare switch must be reserved for
spare use which is not used in a normal condition, weight and size
of the entire system is increased and also manufacturing cost of
the exchange is increased.
SUMMARY OF THE INVENTION
[0015] It is a general object of the present invention to provide
an exchange in which the above-mentioned problems are
eliminated.
[0016] A more specific object of the present invention is to
provide an exchange in which, when a malfunction occurs in one of a
plurality of switches, a transmission path bypassing the
malfunctioning switch can be formed in the absence of a spare
switch in the exchange so as to decrease weight and size of the
entire system.
[0017] In order to achieve the above-mentioned objects, there is
provided according to the present invention an exchange setting a
transmission path for transmitting communication information
through a switch network comprising a plurality of switches, the
switch network provided with a plurality of inputs and a plurality
of outputs so that the transmission path is formed between one of
the inputs and one of the outputs by routing the switches in the
switch network, the exchange changing a route of the transmission
path when a malfunction occurs in one of the switches included in
the transmission path so as to bypass the malfunctioning switch,
the exchange comprising:
[0018] a malfunctioning switch detecting unit detecting a location
of the malfunctioning switch in the switch network; and
[0019] changing means for changing the route of the transmission
path by switching one of the inputs and outputs connected to the
transmission path based on predetermined routing information so as
to bypass the malfunctioning switch.
[0020] According to the above-mentioned invention, when a
malfunction occurs in one of the switches constituting the switch
network, the location of the malfunctioning switch is detected and
the location information is supplied to the changing means. The
location information may include an address of the malfunctioning
switch and information indicating a position of the malfunctioning
switch with respect to the inputs and outputs of the switch
network. For example, if the switches in the switch network are
arranged in a matrix, the location information may include
indication of a column (stage) in which the malfunctioning switch
is included. When the changing means receives the location
information, the changing means changes the route of the
transmission path by changing one of the inputs which is connected
to the transmission path or changing one of the outputs connected
to the transmission path. That is, the input or the output
connected to the transmission path is changed to another input or
output based on the routing information which indicates a route
which bypasses the malfunctioning switch. That is, the route of the
transmission path can be changed to a route which bypasses the
malfunctioning switch by merely changing the input or output of the
switch network.
[0021] Accordingly, the exchange according to the present invention
discriminate the transmission path including the malfunctioning
switch, and the route of the transmission path is changed by
changing the input or the output of the switch network based on the
location of the malfunctioning switch. Thus, the exchange according
to the present invention does not need a spare switch which is not
used when the exchange is operated in a normal condition.
Therefore, the weight and size of the entire system is reduced
which is advantageous for reducing manufacturing cost.
[0022] In the exchange according to the present invention, the
changing means may comprise:
[0023] a storing unit which stores table information indicating a
plurality of routes each of which bypasses one of the switches in
the switch network, each of the routes being indicated in relation
to one of the inputs and outputs of the switch network; and
[0024] a selecting unit selecting one of the routes indicated in
the table information so as to change the route of the transmission
path to bypass the malfunctioning switch.
[0025] Accordingly, if the location of the malfunctioning switch is
detected, a route which bypasses the malfunctioning switch can be
obtained from the table information in relation to the input or the
output of the switch network.
[0026] In one embodiment according to the present invention, the
changing means may comprise:
[0027] an input switching unit switching the input of the switch
network;
[0028] an output switching means switching the output of the switch
network; and
[0029] input and output selecting means for selecting one of the
input switching unit and the output switching unit so that the
changing means changes the route of the transmission path by the
selected one of the input switching unit and the output switching
unit.
[0030] The input and output selecting means may select the input
switching unit when the malfunctioning switch is one of the
switches directly connected to the input switching unit.
Additionally, the input and output selecting means may select the
output switching unit when the malfunctioning switch is one of the
switches directly connected to the output switching unit.
[0031] Additionally., the input and output selecting means may
select the input switching unit when the malfunctioning switch is
one of the switches other than the switches directly connected to
one of the input switching unit and the output switching unit.
Alternately, the input and output selecting means selects the
output switching unit when the malfunctioning switch is one of the
switches other than the switches directly connected to one of the
input switching unit and the output switching unit.
[0032] Other objects, features and advantages of the present
invention will become more apparent from the following detailed
description when read in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a block diagram of a first conventional
exchange;
[0034] FIG. 2 is a block diagram of a second conventional
exchange;
[0035] FIG. 3 is a block diagram of a third conventional
exchange;
[0036] FIG. 4 is a block diagram of an exchange according a first
embodiment of the present invention:
[0037] FIG. 5 is a block diagram of a control unit shown in FIG.
4;
[0038] FIG. 6A is an illustration of a switch network for
explaining an operation of the control unit when a malfunction
occurs in a switch included in a first stage; FIG. 6B is an
illustration for explaining input table (1) information; FIG. 6C is
an illustration for explaining each switch included in the switch
network shown in FIG. 4;
[0039] FIG. 7A is an illustration of the switch network for
explaining an operation of the control unit when a malfunction
occurs in a switch included in a final stage; FIG. 7B is an
illustration for explaining output table (1) information;
[0040] FIG. 8A is an illustration of the switch network for
explaining an operation of the control unit when a malfunction
occurs in a switch included in an intermediate stage; FIG. 8B is an
illustration for explaining input table (2) information;
[0041] FIG. 9A is an illustration of the switch network for
explaining an operation of the control unit when a malfunction
occurs in a switch included in the intermediate stage; FIG. 9B is
an illustration for explaining output table (2) information;
[0042] FIG. 10 is a block diagram of an input switching unit shown
in FIG. 4;
[0043] FIG. 11 is a block diagram of an output switching unit shown
in FIG. 4;
[0044] FIG. 12A is an illustration for explaining an operation of
an input switching unit shown in FIG. 10 when a malfunction occurs
in one of the switches in the first stage; FIG. 12B is an
illustration for explaining an operation of an output switching
unit shown in FIG. 11 when a malfunction occurs in one of the
switches in the first stage;
[0045] FIG. 13A is an illustration for explaining an operation of
an input switching unit shown in FIG. 10 when a malfunction occurs
in one of the switches in the final stage; FIG. 13B is an
illustration for explaining an operation of an output switching
unit shown in FIG. 11 when a malfunction occurs in one of the
switches in the final stage;
[0046] FIG. 14 is a flowchart of an operation of the exchange shown
in FIG. 4;
[0047] FIG. 15A is an illustration for explaining a transmission
path formed in the switch network before a change is made to the
transmission path when a malfunction occurs in one of the switches
in the first stage; FIG. 15B is an illustration for explaining the
transmission path of FIG. 15A after the change;
[0048] FIG. 16A is an illustration for explaining a transmission
path formed in the switch network before a change is made to the
transmission path when a malfunction occurs in one of the switches
in the final stage; FIG. 16B is an illustration for explaining the
transmission path of FIG. 15A after the change;
[0049] FIG. 17A is an illustration for explaining a transmission
path formed in the switch network before a change is made to the
transmission path when a malfunction occurs in one of the switches
in the intermediate stage; FIG. 17B is an illustration for
explaining the transmission path of FIG. 15A after the change;
and
[0050] FIG. 18A is an illustration for explaining a transmission
path formed in the switch network before a change is made to the
transmission path when a malfunction occurs in one of the switches
in the first stage; FIG. 18B is an illustration for explaining the
transmission path of FIG. 15A after the change.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0051] A description will now be given of an exchange according to
a first embodiment of the present invention.
[0052] FIG. 4 is a block diagram of the exchange according to the
first embodiment of the present invention. The exchange shown in
FIG. 4 comprises a switch network 1, a control unit 2, an input
switching unit 3 and an output switching unit 4. When a malfunction
occurs in one of a plurality of switches in the switch network 1,
the exchange switches a transmission path so as to bypass the
malfunctioning switch.
[0053] The switch network 1 of the present embodiment comprises
twelve (12) switches each having two (2) inputs and two (2) outputs
so as to constitute a switch network having eight (8) inputs and
eight (8) outputs. For example, the eight (8) inputs of the switch
network 1 are provided with eight (8) input addresses from "000" to
"111", and eight (8) outputs are provided with eight (8) output
addresses from "000" to "111". In the switch network 1, the
switches are arranged in a 3.times.4 matrix. Four (4) switches in
the first stage (first column) are connected to the inputs of the
switch network 1. The first stage is referred to as a malfunction
stage (a). Four (4) switches in the final stage (third column) are
connected to the outputs of the switch network 1. The final stage
is referred to as a malfunction stage (c). Four (4) switches in the
intermediate stage (second column) are not connected with either
the inputs or the outputs. The intermediate stage is defined as a
malfunction stage (b). Additionally, the switches in the first row
(the uppermost row) are given a switch address "00"; the switches
in the second row are given a switch address "01"; the switches in
the third row are given a switch address "10"; the switches in the
fourth row (the lowermost row) are given a switch address "11".
[0054] The switch network 1 has a function to change a route of a
transmission path formed in the switch network 1 based on
predetermined routing information of a previously set route and
location information of a malfunctioning switch. Although the
switch network 1 of the present embodiment comprises twelve (12)
switches and has eight (8) inputs and eight (8) outputs, the number
of switches, the number of inputs and the number of outputs are not
limited to those numbers.
[0055] The control unit 2 serves as a changing means for changing a
route of a transmission path formed in the switch network 1. That
is, when a malfunction occurs in the switch network 1, the control
unit 2 sets a final stage malfunction flag and produces input and
output unit changing information. The final stage malfunction flag
is set for selecting one of the ways to bypass the malfunctioning
switch by either changing the input address or output address. The
selection by the controller is performed based on address
information of the malfunctioning switch and information of the
malfunction stage in which the malfunction switch is included. The
input and output unit changing information is used for changing a
transmission path in the switch network 1 so as to bypass the
malfunctioning switch.
[0056] The input switching unit 3 serves as an input switching
means of the changing means. That is, when a malfunction occurs in
the switch network 1, the input switching unit 3 switches a path to
the inputs of the switch network 1 based on the input and output
unit changing information produced by the control unit 2.
[0057] The output switching unit 4 serves as an output switching
means of the changing means. That is, when a malfunction occurs in
the switch network 1, the input switching unit 3 switches a path
from the outputs of the switch network 1 based on the final stage
malfunction flag set by the control unit 2.
[0058] A description will now be given, with reference to FIG. 5,
of the control unit 2 shown in FIG. 4 in more detail.
[0059] As shown in FIG. 5, the control unit 2 comprises a
malfunctioning switch detecting unit 5, an input and output table
storing unit 6, an input table (1) storing unit 7, an output table
(1) storing unit 10, a selecting unit 11 and a final stage flag
producing unit 12.
[0060] The malfunctioning switch detecting unit 5 serves as a
discriminating means for discriminating a switch in which a
malfunction occurs. That is, when a malfunction occurs in one of
the switches in the switch network 1, the malfunctioning switch
detecting unit 5 detects the malfunctioning switch.
[0061] The input table (1) storing unit 7 serves as a storing means
for storing an input table (1) information as predetermined routing
information. The input table (1) information is referred to when
the malfunctioning switch is included in the malfunction stage (a)
(the first stage) of the switch network 1 so as to change a
transmission path to bypass the malfunctioning switch. That is, the
input table (1) storing unit 7 stores the input table (1)
information which indicates each switch in the switch network 1 in
relation to transmission paths each of which bypasses each switch
in the switch network 1.
[0062] The output table (1) storing unit 10 serves as a storing
means for storing an output table (1) information as predetermined
routing information. The output table (1) information is referred
to when the malfunctioning switch is included in the malfunction
stage (c) (the final stage) of the switch network 1 so as to change
a transmission path to bypass the malfunctioning switch. That is,
the output table (1) storing unit 10 stores the output table (1)
information which indicates each switch in the switch network 1 in
relation to transmission paths each of which bypasses each switch
in the switch network 1.
[0063] The input and output table storing unit 6, which serves as a
storing means, comprises at least one of an input table (2)
information storing unit 8 for storing an input table (2)
information and an output table (2) information storing unit 9 for
storing an output table (2) information. The input table (2)
information or the output table (2) information is referred to when
a malfunctioning switch is included in the malfunction stage (b)
(the intermediate stage). The input table (2) information and the
output table (2) information serves a function similar to the input
table (1) information and the output table (1) information.
[0064] The selecting unit 11 serves as a path selecting means for
selecting a transmission path which bypasses a malfunctioning
switch. That is, when a malfunction occurs in one of the switches
in the switch network 1, the selecting unit 11 selects a
transmission path which bypasses the malfunctioning switch based on
the input table (1) information, the output table (1) information,
the input table (2) information and the output table (2)
information.
[0065] The final stage malfunction flag producing unit 12 sends a
notification to the input switching unit 3 so as to set the final
stage malfunction flag to "ON" when switching is performed by the
output switching unit 4.
[0066] A description will now be given, with reference to FIGS. 6A,
6B and 6C, of an operation of the control unit 2 when the input
table (1) information stored in the input table (1) storing unit 7
is referred to.
[0067] FIG. 6A shows a case in which a malfunction occurs in a
switch having a switch address "00" in the malfunction stage (a).
In the case shown in FIG. 6A, an original routing information is
"000111" which indicates a transmission path routing from the input
having the address "000" to the output having the address "111"
(indicated by a bold solid line in FIG. 6A). Each of the switches
constituting the switch network 1 has a 0-input terminal, a
0-output terminal, a 1-input terminal and a 1-output terminal as
shown in FIG. 6C. The input address "000" indicates the input
terminals of the malfunction stages (a), (b) and (c), respectively.
The output address "111" indicates the output terminals of the
malfunction stages (a), (b) and (c), respectively. Accordingly,
communication information input to the input address "000" of the
switch network 1 is first input to the 0-input terminal of the
switch having the switch address "00" in the malfunction stage (a),
and output from the 1-output terminal of the same switch. Then, the
communication information is input to the 0-input terminal of the
switch having the switch address "01" in the malfunction stage (b),
and output from the 1-output terminal of the same switch.
Thereafter, the communication information is input to the 0-input
terminal of the switch having the switch address "11" in the
malfunction stage (c), and output from the 1-output terminal of the
same switch. Finally, the communication information is output from
the output address "111" of the switch network 1.
[0068] When the malfunctioning switch detecting unit 5 detects the
malfunctioning switch, the selecting unit 11 refers to the input
table (1) information stored in the input table (1) storing unit 7
since the malfunctioning switch is included in the malfunction
stage (a) (the first stage). The input table (1) information
provides the information as shown in FIG. 6B. Accordingly, the
control unit 2 refers to, as input and output information, a case
in which the input address is "000" and the switch address "00" of
the malfunctioning switch (indicated by hatched portion of FIG.
6B). In this case, an input address after change indicates other
than "*00". This means that the selecting unit 11 should select
input addresses other than the input addresses "000" and "100" so
as to change a transmission path to bypass the malfunctioning
switch. Accordingly, for example, the malfunctioning switch can be
bypassed if the routing information supplied to the input switching
unit 3 is changed to "001111". It should be noted that the routing
information is not limited to "001111".
[0069] A description will now be given, with reference to FIGS. 7A
and 7B, of an operation of the control unit 2 when the output table
(1) information stored in the output table (1) storing unit 10 is
referred to.
[0070] FIG. 7A shows a case in which a malfunction occurs in a
switch having a switch address "11" in the malfunction stage (c).
In the case shown in FIG. 7A, an original routing information is
"000111" which indicates a transmission path routing from the input
having the address "000" to the output having the address "111"
(indicated by a bold solid line in FIG. 7A).
[0071] When the malfunctioning switch detecting unit 5 detects the
malfunctioning switch, the selecting unit 11 refers to the output
table (1) information stored in the output table (1) storing unit
10 since the malfunctioning switch is included in the malfunction
stage (c) (the final stage). The output table (1) information
provides the information as shown in FIG. 7B. Accordingly, the
control unit 2 refers to, as input and output information, a case
in which the output address is "111" and the switch address "11" of
the malfunctioning switch (indicated by hatched portion of FIG.
7B). In this case, an output address after change indicates other
than "11*". This means that the selecting unit 11 should select
output addresses other than the output addresses "111" and "110" so
as to change a transmission path to bypass the malfunctioning
switch. Accordingly, for example, the malfunctioning switch can be
bypassed if the routing information supplied to the input switching
unit 3 is changed to "000011". It should be noted that the routing
information is not limited to "000011".
[0072] A description will now be given, with reference to FIGS. 8A
and 8B, of an operation of the control unit 2 when the input table
(2) information stored in the input table (2) storing unit 8 is
referred to.
[0073] FIG. 8A shows a case in which a malfunction occurs in a
switch having a switch address "01" in the malfunction stage (b).
In the case shown in FIG. 7A, an original routing information is
"000111" which indicates a transmission path routing from the input
having the address "000" to the output having the address "111"
(indicated by a bold solid line in FIG. 8A).
[0074] When the malfunctioning switch detecting unit 5 detects the
malfunctioning switch, the selecting unit 11 refers to the input
table (2) information stored in the input table (2) storing unit 8
since the malfunctioning switch is included in the malfunction
stage (b) (the intermediate stage). The information table (2)
information provides the information as shown in FIG. 8B.
Accordingly, the control unit 2 refers to, as input and output
information, a case in which the input address is "000" and the
switch address "01" of the malfunctioning switch (indicated by
hatched portion of FIG. 8B). In this case, an input address after
change indicates other than "**1". This means that the selecting
unit 11 should select input addresses other than the input
addresses "000", "010", "100" and "110" so as to change a
transmission path to bypass the malfunctioning switch. Accordingly,
for example, the malfunctioning switch can be bypassed if the
routing information supplied to the input switching unit 3 is
changed to "001111". It should be noted that the routing
information is not limited to "001111".
[0075] A description will now be given, with reference to FIGS. 9A
and 9B, of an operation of the control unit 2 when the output table
(2) information stored in the output table (2) storing unit 9 is
referred to.
[0076] FIG. 9A shows a case in which a malfunction occurs in a
switch having a switch address "01" in the malfunction stage (c).
In the case shown in FIG. 9A, an original routing information is
"000111" which indicates a transmission path routing from the input
having the address "000" to the output having the address "111"
(indicated by a bold solid line in FIG. 9A).
[0077] When the malfunctioning switch detecting unit 5 detects the
malfunctioning switch, the selecting unit 11 refers to the output
table (2) information stored in the output table (2) storing unit 9
since the malfunctioning switch is included in the malfunction
stage (b) (the intermediate stage). The output table (2)
information provides the information as shown in FIG. 9B.
Accordingly, the control unit 2 refers to, as input and output
information, a case in which the output address is "111" and the
switch address "01" of the malfunctioning switch (indicated by
hatched portion of FIG. 9B). In this case, an output address after
change indicates other than "1**". This means that the selecting
unit 11 should select output addresses other than the output
addresses "111", "110", "101" and "100" so as to change a
transmission path to bypass the malfunctioning switch. Accordingly,
for example, the malfunctioning switch can be bypassed if the
routing information supplied to the input switching unit 3 is
changed to "000011". It should be noted that the routing
information is not limited to "000011".
[0078] FIG. 10 is a block diagram of the input switching unit 3
shown in FIG. 4. In FIG. 10, the input switching unit 3 comprises a
routing information changing unit 21, a final stage malfunction
flag 22 and a switch 23. The input switching unit 3 changes the
routing information contained in the frame format of the
communication information, when a malfunction occurs in the switch
network 1, based on the input and output unit changing information
and the final stage malfunction flag which are sent from the
control unit 2.
[0079] The routing information changing unit 21 changes the
contents of a frame format (header) of the communication
information, when a malfunction occurs in the switch network 1,
based on the input and output unit changing information sent from
the control unit 2. If the malfunctioning switch is included in the
first stage, the routing information changing unit 21 changes the
input; address. If the malfunctioning switch is included in the
final stage, the routing information changing unit 21 changes the
output address. If the malfunctioning switch is included in the
intermediate stage, the routing information changing unit 21
changes one of the input address and the output address.
[0080] The final stage malfunction flag changing unit 22 changes
the status of the final stage malfunction flag contained in the
frame format of the communication information, when a malfunction
occurs in the switch network 1, based on the final stage
malfunction flag sent from the control unit 2. When the
malfunctioning switch is included in the final stage of the switch
network 1 or when the malfunctioning switch is included in the
intermediate stage of the switch network 1 and the output address
is to be changed, the final stage malfunction flag changing unit 22
sets the final stage malfunction flag to "1".
[0081] The switch 23 changes an input direction of the
communication information based on the changed frame format of the
communication information when the malfunctioning switch is
included in the first stage of the switch network 1 or when the
malfunctioning switch is included in the intermediate stage and the
input address is to be changed.
[0082] FIG. 11 is a block diagram of the output switching unit 4
shown in FIG. 4. In FIG. 11, the output switching unit 4 comprises
a final stage malfunction flag determining unit 31 and a switch 32.
The output switching unit 4 switches an outputting direction of the
communication information to be sent to one of the output
addresses, when a malfunction occurs in the switch network 1, based
on the input and output unit changing information and the final
stage malfunction flag which are sent from the control unit 2.
[0083] The final stage malfunction flag determining unit 31
determines the status of the final stage malfunction flag contained
in the frame format of the communication information. When a result
of the determination of the final stage malfunction flag
determining unit 31 indicates "ON", the switch 32 changes the
output address based on the routing information contained in the
frame format of the communication information.
[0084] FIGS. 12A is an illustration for explaining a change in the
frame format made by the input switching unit 3 shown in FIG. 10
when a malfunction occurs in one of the switches included in the
first stage as is in the case shown in FIG. 6A. FIG. 12B is an
illustration for explaining a change in the frame format made by
the output switching unit 4 shown in FIG. 11 when a malfunction
occurs in one of the switches included in the first stage as is in
the case shown in FIG. 6A. It should be noted that a change of the
frame format when the malfunctioning switch is included in the
intermediate stage and the input address is to be changed is the
same as that of the case in which the malfunctioning switch is
included in the first stage of the switch network 1.
[0085] In FIG. 12A, when the frame format (routing information
before change "000111", a final stage malfunction flag "OFF") of
the communication information is input to the input address "000"
of the input switching unit 3, the routing information changing
unit 21 changes the routing information to, "001111", for example,
based on the input and output unit changing information produced by
the control unit 2 as is in the case shown in FIGS. 6A and 6B. At
this time, the routing information before change is maintained.
[0086] When the routing information is changed to "001111", the
input address in the frame format of the communication information
is changed from "000" to "001" by the switch 23. The communication
information input to the input address "001" of the switch network
1 is output from the output address "111" of the switch network
1.
[0087] As shown in FIG. 12B, the frame format of the communication
information output from the output address "111" of the switch
network 1 is output to the output address "111" of the output
switching unit 4 via the final stage malfunction flag determining
unit 31 and the switch 32 while the present information is also
maintained.
[0088] FIGS. 13A is an illustration for explaining a change in the
frame format made by the input switching unit 3 shown in FIG. 10
when a malfunction occurs in one of the switches included in the
final stage as is in the case shown in FIG. 7A. FIG. 13B is an
illustration for explaining a change in the frame format made by
the output switching unit 4 shown in FIG. 11 when a malfunction
occurs in one of the switches included in the final stage as is in
the case shown in FIG. 7A. It should be noted that a change in the
frame format when the malfunctioning switch is included in the
intermediate stage and the output address is to be changed is the
same as that of the case in which the malfunctioning switch is
included in the final stage of the switch network 1.
[0089] In FIG. 13A, when the frame format (routing information
before change "000111", a final stage malfunction flag "OFF") of
the communication information is input to the input address "000"
of the input switching unit 3, the routing information changing
unit 21 changes the routing information to "000011", for example,
based on the input and output unit changing information produced by
the control unit 2 as is in the case shown in FIGS. 7A and 7B. At
this time, the routing information before change is maintained.
[0090] When the routing information is changed to "000011", the
status of the final stage malfunction flag is changed to "ON" by
the final stage malfunction flag changing unit 22. Additionally,
the input address "000" is output to the switch network 1 via the
switch 23. Thus, the communication information input to the input
address "000" of the switch network 1 is output from the output
address "011" of the switch network 1.
[0091] As shown in FIG. 13B, the frame format of the communication
information output from the output address "011" of the switch
network 1 is output to the output address "111" of the output
switching unit 4 after the status of the final stage malfunction
flag is determined by the final stage malfunction flag determining
unit 31 and changed to the routing information before change "111"
while the present information is also maintained.
[0092] FIG. 14 is a flowchart of an operation of the exchange
according to the present embodiment when the exchange is in a
normal condition or when a malfunction occurs in the switch network
1 as shown in FIGS. 15A and 15B, 16A and 16B, 17A and 17B, and 18A
and 18B. In the operation shown in FIG. 14, it is assumed that the
communication information having routing information "000111" in
the frame format is input, in step S1, to the input address "000"
of the input switching unit 3 when the exchange is normally
operated. The communication information is input to the input
address "000" of the switch network 1 as shown in FIGS. 15A, 16A,
17A and 18A via the routing information changing unit 21, the final
stage malfunction flag changing unit 22 and the switch 23 in the
input switching unit 3.
[0093] Then, in step S2, a routing from the input address "000" to
the output address "111" is performed. Each of the switches
included in the switch network 1 has the 0-input terminal, 1-input
terminal, 0-output terminal and the 1-output terminal as shown in
FIG. 6C. Each digit of the input address "000" corresponds to the
input terminal of each of the switches in the respective stages
(a), (b) and (c). Each digit of the output address "111"
corresponds to the output terminal of each of the switches in the
respective stages (a), (b) and (c). Specifically, as shown in FIG.
15A, the communication information input to the input address "000"
of the switch network 1 is input to the 0-input terminal of the
switch having the switch address "00" in the stage (a), and is
output from 1-output terminal of the same switch. The communication
information is then input to the 0-input terminal of the switch
having the switch address "01" in the stage (b), and is output from
the 1-output terminal of the same switch. After that, the
communication information is input to the 0-input terminal of the
switch having the switch address "11" in the stage (c), and is
output from the 1-output terminal of the same switch. Finally, the
communication information is output from the output address "111"
of the switch network 1.
[0094] The communication information output from the switch network
1 is input to the input address "111" of the output switching unit
4. In step S3, the final stage malfunction flag determining unit 31
of the output switching unit 4 determines whether the final stage
malfunction flag is "ON" or "OFF". In this case, since the switch
network 1 is normally operating, it is determined that the final
stage malfunction flag is "OFF". Thus, the communication
information is output, in step S4, to the output address "111" of
the output switching unit 4 via the switch 32.
[0095] On the other hand, when a malfunction occurs in one of the
switches in the switch network 1 in step S11, the exchange
according to the present embodiment detects, in step S12, the
location of the malfunctioning switch by the malfunctioning switch
detecting unit 5.
[0096] If the switch address "00" in the stage (a) (the first
stage) is detected by the malfunction detecting unit 5 as the
location of the malfunctioning switch, the selecting unit 11 refers
to the input table (1) information stored in the input table (1)
storing unit 7 in step S13. The input table (1) information
provides, for example, the information shown in FIG. 6B, and the
selecting unit 11 refers to the "input address after change" in a
case in which the input address of the switch network 1 is "000"
and the address of the malfunctioning switch is "00" (indicated by
hatched portions in FIG. 6B). Thus, the selecting unit 11 selects,
in step S14, a transmission path which routes from one of the input
addresses other than the input addresses "000" and "100" to the
output address "111" so as to bypass the malfunctioning switch.
Accordingly, the selecting unit 11 sends to the input switching
unit 3 the input and output unit changing information which
provides an instruction to change the routing information to
"001111", for example. It should be noted that the routing
information to be set is not limited to "001111".
[0097] When the communication information having the routing
information "001111" in the frame format is input to the input
address "000" of the input switching unit 3, the routing
information changing unit 21 of the input switching unit 3 changes
the routing information to "001111", in step S15, based on the
input and output unit changing information produced by the
selecting unit 11.
[0098] After the routing information in the frame format of the
communication information is changed to "001111", the communication
information is passed through the final stage malfunction flag
changing unit 22. Thereafter, the switch 23 changes, in step S16,
the input address of the switch network 1, to which the
communication information is input, from "000" to "001". Thus, the
communication information is output from the switch 23 to the input
address "001" of the switch network 1.
[0099] Then, in step S2, a routing from the input address "001" to
the output address "111" is performed. Each digit of the input
address "001" corresponds to the input terminal of each of the
switches in the respective stages (a), (b) and (c). Each digit of
the output address "111" corresponds to the output terminal of each
of the switches in the respective stages (a), (b) and (c).
Specifically, as shown in FIG. 15B, the communication information
input to the input address "001" of the switch network 1 is input
to the 0-input terminal of the switch having the switch address
"00" in the stage (a), and is output from 1-output terminal of the
same switch. The communication information is then input to the
0-input terminal of the switch having the switch address "11" in
the stage (b), and is output from the 1-output terminal of the same
switch. After that, the communication information is input to the
0-input terminal of the switch having the switch address "11" in
the stage (c), and is output from the 1-output terminal of the same
switch. Finally, the communication information is output from the
output address "111" of the switch network 1.
[0100] The communication information output from the switch network
1 is input to the input address "111" of the output switching unit
4. In step S3, the final stage malfunction flag determining unit 31
of the output switching unit 4 determines whether the final stage
malfunction flag is "ON" or "OFF". In this case, since the
malfunctioning switch is included in the first stage, it is
determined that the final stage malfunction flag is "OFF". Thus,
the communication information is output, in step S4, to the output
address "111" of the output switching unit 4 via the switch 32.
[0101] In the process of step S12, if the switch address "11" in
the stage (c) (the final stage) is detected by the malfunction
detecting unit 5 as the location of the malfunctioning switch as
shown in FIG. 16A, the selecting unit 11 refers to the output table
(1) information stored in the output table (1) storing unit 10 in
step S17. The output table (1) information provides, for example,
the information shown in FIG. 7B, and the selecting unit 11 refers
to the "output address after change" in a case in which the output
address of the switch network 1 is "*11" and the address of the
malfunctioning switch is "11" (indicated by hatched portions in
FIG. 7B). Thus, the selecting unit 11 selects, in step S18, a
transmission path which is connected to output addresses other than
the output addresses "111" and "110" so as to bypass the
malfunctioning switch. Accordingly, the selecting unit 11 sends to
the input switching unit 3 the input and output unit changing
information which instructs to change the routing information to
"001111", for example. It should be noted that the routing
information to be set is not limited to "001111".
[0102] When the communication information having the routing
information "001111" in the frame format is input to the input
address "000" of the input switching unit 3, the routing
information changing unit 21 of the input switching unit 3 changes
the routing information to "001111", in step S19, based on the
input and output unit changing information produced by the
selecting unit 11.
[0103] After the routing information in the frame format of the
communication information is changed to "001111", the final stage
malfunction flag changing unit 22 changes, in step S19, the final
stage malfunction flag to "ON" and the communication information is
output to the input address "000" of the switch network 1 via the
switch 23.
[0104] Then, in step S2, a routing from the input address "001" to
the output address "111" is performed in the switch network 1.
[0105] Each digit of the input address "000" corresponds to the
input terminal of each of the switches in the respective stages
(a), (b) and (c). Each digit of the output address "011"
corresponds to the output terminal of each of the switches in the
respective stages (a), (b) and (c). Specifically, as shown in FIG.
16B, the communication information input to the input address "000"
of the switch network 1 is input to the 0-input terminal of the
switch having the switch address "00" in the stage (a), and is
output from the 0-output terminal of the same switch. The
communication information is then input to the 0-input terminal of
the switch having the switch address "00" in the stage (b), and is
output from the 1-output terminal of the same switch. After that,
the communication information is input to the 0-input terminal of
the switch having the switch address "01" in the stage (c), and is
output from the 1-output terminal of the same switch. Finally, the
communication information is output from the output address "011"
of the switch network 1.
[0106] The communication information output from the switch network
1 is input to the input address "011" of the output switching unit
4. In step S3, the final stage malfunction flag determining unit 31
of the output switching unit 4 determines whether the final stage
malfunction flag is "ON" or "OFF". In this case, since the
malfunctioning switch is included in the final stage, it is
determined that the final stage malfunction flag is "ON". Thus, the
switch 32 changes, in step 5, the output address to which the
communication information is output to the original output address
"111", and the communication information is output to the output
address "111" of the output switching unit 4 via the switch 32.
Since the switching operation of the output switching unit 4 can be
performed based on the determination by the final stage malfunction
flag determining unit 31 as to whether the final stage malfunction
flag is "ON" or "OFF", the output switching unit 4 can perform the
switching of the output address without a direct instruction from
the control unit 2.
[0107] In the process of step S12, if the switch address "01" in
the stage (b) (the intermediate stage) is detected by the
malfunction detecting unit 5 as the location of the malfunctioning
switch as shown in FIG. 17A and if an instruction is provided to
change the input address so as to bypass the malfunctioning switch
when the malfunctioning switch is located in the intermediate stage
of the switch network 1, the selecting unit 11 refers to the input
table (2) information stored in the input table (2) storing unit 8
in step S20.
[0108] The input table (2) information provides, for example, the
information shown in FIG. 8B, and the selecting unit 11. refers to
the "input address after change" in a case in which the input
address of the switch network 1 is "000" and the address of the
malfunctioning switch is "01" (indicated by hatched portions in
FIG. 8B). Thus, the selecting unit 11 selects, in step S22, a
transmission path routing from an input address other than the
input addresses "000", "010", "100" and "110" to the output address
"111" so as to bypass the malfunctioning switch. Accordingly, the
selecting unit 11 sends to the input switching unit 3 the input and
output unit changing information which instructs to change the
routing information to "001111", for example. It should be noted
that the routing information to be set is not limited to
"001111".
[0109] When the communication information having the routing
information "001111" in the frame format is input to the input
address "000" of the input switching unit 3, the routing
information changing unit 21 of the input switching unit 3 changes
the routing information to "001111", in step S23, based on the
input and output unit changing information produced by the
selecting unit 11.
[0110] After the routing information in the frame format of the
communication information is changed to "001111", the communication
information is passed through the final stage malfunction flag
changing unit 22. Thereafter, the final stage malfunction flag
changing unit 22 changes, in step S24, the input address of the
switch network 1, to which the communication information is input,
from "000" to "001". Thus, the communication information is output
from the switch 23 to the input address "001" of the switch network
1.
[0111] Then, in step S2, a routing from the input address "001" to
the output address "111" is performed in the switch network 1.
[0112] Each digit of the.input address "001" corresponds to the
input terminal of each of the switches in the respective stages
(a), (b) and (c). Each digit of the output address "111"
corresponds to the output terminal of each of the switches in the
respective stages (a), (b) and (c). Specifically, as shown in FIG.
17B, the communication information input to the input address "000"
of the switch network 1 is input to the 0-input terminal of the
switch having the switch address "00" in the stage (a), and is
output from 1-output terminal of the same switch. The communication
information is then input to the 0-input terminal of the switch
having the switch address "01" in the stage (b), and is output from
the 1-output terminal of the same switch. After that, the
communication information is input to the 0-input terminal of the
switch having the switch address "11" in the stage (c), and is
output from the 1-output terminal of the same switch. Finally, the
communication information is output from the output address "111"
of the switch network 1.
[0113] The communication information output from the switch network
1 is input to the input address "111" of the output switching unit
4. In step S3, the final stage malfunction flag determining unit 31
of the output switching unit 4 determines whether the final stage
malfunction flag is "ON" or "OFF". In this case, since the
instruction is provided so as to change the input address when a
malfunction occurs in one of the switches in the intermediate
stage, it is determined that the final stage malfunction flag is
"OFF". Thus, the communication information is output, in step S4,
to the output address "111" of the output switching unit 4 via the
switch 32.
[0114] In the process of step S12, if the switch address "11" in
the stage (c) (the final stage) is detected by the malfunction
detecting unit 5 as the location of the malfunctioning switch as
shown in FIG. 18A and if an instruction is provided so as to change
the output address of the switch network 1 when a malfunction
occurs in one of the switches in the intermediate stage, the
selecting unit 11 refers to the output table (2) information stored
in the output table (2) storing unit 9 in step S21. The output
table (1) information provides, for example, the information shown
in FIG. 9B, and the selecting unit 11 refers to the "output address
after change" in a case in which the output address of the switch
network 1 is "111" and the address of the malfunctioning switch is
"01" (indicated by hatched portions in FIG. 9B). Thus, the
selecting unit 11 selects, in step S22, a transmission path which
is connected to an output address other than the output addresses
"111", "110", "101 and "100" so as to bypass the malfunctioning
switch. Accordingly, the selecting unit 11 sends to the input
switching unit 3 the input and output unit changing information
which provides an instruction to change the routing information to
"000011", for example. It should be noted that the routing
information to be set is not limited to "000011".
[0115] When the communication information having the routing
information "000011" in the frame format is input to the input
address "000" of the input switching unit 3, the routing
information changing unit 21 of the input switching unit 3 changes
the routing information to "000011", in step S23, based on the
input and output unit changing information produced by the
selecting unit 11.
[0116] After the routing information in the frame format of the
communication information is changed to "000011", the final stage
malfunction flag changing unit 22 changes, in step S23, the final
stage malfunction flag to "ON" and the communication information is
output to the input address "000" of the switch network 1 via the
switch 23.
[0117] Then, in step S2, a routing from the input address "000" to
the output address "011" is performed in the switch network 1.
[0118] Each digit of the input address "000" corresponds to the
input terminal of each of the switches in the respective stages
(a), (b) and (c). Each digit of the output address "011"
corresponds to the output terminal of each of the switches in the
respective stages (a), (b) and (c). Specifically, as shown in FIG.
18B, the communication information input to the input address "000"
of the switch network 1 is input to the 0-input terminal of the
switch having the switch address "00" in the stage (a), and is
output from the 0-output terminal of the same switch. The
communication information is then input to the 0-input terminal of
the switch having the switch address "00" in the stage (b), and is
output from the 1-output terminal of the same switch. After that,
the communication information is input to the 0-input terminal of
the switch having the switch address "01" in the stage (c), and is
output from the 1-output terminal of the same switch. Finally, the
communication information is output from the output address "011"
of the switch network 1.
[0119] The communication information output from the switch network
1 is input to the input address "011" of the output switching unit
4. In step S3, the final stage malfunction flag determining unit 31
of the output switching unit 4 determines whether the final stage
malfunction flag is "ON" or "OFF". In this case, since the
instruction is provided so as to change the output address of the
switch network 1 when a malfunction occurs in one of the switches
in the intermediate switch, it is determined that the final stage
malfunction flag is "ON". Thus, the switch 32 changes, in step 5,
the output address, to which the communication information is
output, to the original output address "111", and the communication
information is output to the output address "111" of the output
switching unit 4 via the switch 32. Since the switching operation
of the output switching unit 4 can be performed based on the
determination by the final stage malfunction flag determining unit
31 as to whether the final stage malfunction flag is "ON" or "OFF"
by the, the output switching unit 4 can perform the switching of
the output address without a direct instruction from the control
unit 2.
[0120] As mentioned above, according to the exchange of the present
embodiment, when a malfunction occurs in the switch network 1 in
which a transmission path is formed to transmit the communication
information, only the transmission path including the
malfunctioning switch is changed so as to bypass the malfunctioning
switch. Thus, the exchange according to the present embodiment does
not have spare switches which would cause an increase in the weight
and size of the entire system.
[0121] The present invention is not limited to the specifically
disclosed embodiments, and variations and modifications may be made
without departing from the scope of the present invention.
* * * * *