U.S. patent application number 09/123083 was filed with the patent office on 2002-05-23 for digital one-link relaying system for communication data in a cell transmission network.
Invention is credited to SHIBUYA, KAZUHIRO.
Application Number | 20020061017 09/123083 |
Document ID | / |
Family ID | 17828101 |
Filed Date | 2002-05-23 |
United States Patent
Application |
20020061017 |
Kind Code |
A1 |
SHIBUYA, KAZUHIRO |
May 23, 2002 |
DIGITAL ONE-LINK RELAYING SYSTEM FOR COMMUNICATION DATA IN A CELL
TRANSMISSION NETWORK
Abstract
When passing-particular-equipment identification data which
indicates passing particular transmission equipment has been
detected, two opposing CLAD blocks exchange items of information on
the transmission or reception addresses of ATM cells in the
respective CLAD blocks, via an exchange (#2). Besides, each CLAD
block or an ATM cell switch block alters the route of the cell
inside the transmission equipment, on the basis of the exchanged
information. In consequence, the ATM cell left intact can be
relayed toward its destination without causing voice data itself to
pass through the exchange (#2). As a result, the numbers of times
of coding/decoding and cell assembling/disassembling operations for
the voice data match the numbers of times corresponding to one link
of transmission equipment.
Inventors: |
SHIBUYA, KAZUHIRO;
(KANAGAWA, JP) |
Correspondence
Address: |
HELFGOTT & KARAS
EMPIRE STATE BUILDING
60TH FLOOR
NEW YORK
NY
101180110
|
Family ID: |
17828101 |
Appl. No.: |
09/123083 |
Filed: |
July 27, 1998 |
Current U.S.
Class: |
370/389 ;
370/386 |
Current CPC
Class: |
H04L 2012/5685 20130101;
H04L 12/5601 20130101; H04L 2012/5653 20130101; H04L 2012/5671
20130101 |
Class at
Publication: |
370/389 ;
370/386 |
International
Class: |
H04L 012/56 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 28, 1997 |
JP |
09-296021 |
Claims
What is claimed is:
1. A cell transmission equipment having a function of assembling
communication data received from an exchange, into a cell of fixed
length, and then transmitting the cell to a cell transmission
network, a function of receiving communication data in the form of
a cell, from the cell transmission network, and thereafter
disassembling the cell and transmitting the resulting communication
data to the exchange, and a function of determining a communication
channel inside the equipment for use in connecting the equipment
with the exchange, on the basis of data contained in a cell being
processed within the equipment, comprising: a
passing-particular-equipment identification data insertion circuit
which inserts passing-particular-equipment identification data into
said communication data to be transmitted to said exchange, the
passing-particular-equipment identification data serving to
identify whether or not said communication data is in a relaying
state in which it is to be relayed by the particular equipment; a
passing-particular-equipm- ent identification data reception
circuit which receives said passing-particular-equipment
identification data from within the communication data received
from said exchange; a particular-communicatio- n-channel
identification data insertion circuit which inserts
particular-communication-channel identification data into said
communication data to be transmitted to said exchange, the
particular-communication-channel identification data indicating a
communication channel of a cell correspondent to said communication
data, when the received passing-particular-equipment identification
data indicates the relaying state; a
particular-communication-channel identification data reception
circuit which receives said particular-communication-channel
identification data from within said communication data received
from said exchange; and a cell route alteration circuit which
alters a route of the cell inside said equipment, on the basis of
the received particular-communication-channel identification
data.
2. A cell transmission equipment having a cell assembly/disassembly
device which assembles communication data received from an
exchange, into a cell of fixed length, and then transmits the cell
to a cell transmission network, and which receives communication
data in the form of a cell, from the cell transmission network, and
thereafter disassembles the cell and transmits the resulting
communication data to the exchange, and a function of determining a
communication channel inside the equipment for use in connecting
the equipment with the exchange, on the basis of data contained in
a cell being processed within the equipment, comprising: a
passing-particular-equipment identification data insertion circuit
which inserts passing-particular-equipment identification data into
said communication data to be transmitted to said exchange, the
passing-particular-equipment identification data serving to
identify whether or not said communication data is in a relaying
state in which it is to be relayed by the particular equipment; a
passing-particular-equipm- ent identification data reception
circuit which receives said passing-particular-equipment
identification data from within the communication data received
from said exchange; a particular-communicatio- n-channel
identification data insertion circuit which inserts
particular-communication-channel identification data into said
communication data to be transmitted to said exchange, the
particular-communication-channel identification data indicating a
transmitting communication channel of the cell assembly/disassembly
device which is processing the cell correspondent to said
communication data, when the received passing-particular-equipment
identification data indicates the relaying state; a
particular-communication-channel identification data reception
circuit which receives said particular-communication-channel
identification data from within said communication data received
from said exchange; a loop-back circuit which loops said cell
received from said cell transmission network by said cell
assembly/disassembly device, back to a side of said cell
transmission network, when said passing-particular-equipment
identification data which is contained in said cell
assembly/disassembly device being processing said cell
correspondent to said communication data received from said
exchange and which has been received together with said
communication data indicates said relaying state; and a cell route
alteration circuit which alters a route of said cell inside said
equipment in said cell assembly/disassembly device, in such a way
that the transmitting communication channel of said cell to be
looped back is altered to one which is indicated by said
particular-communication-channel identification data received from
said exchange together with said communication data.
3. A cell transmission equipment having a cell assembly/disassembly
device which assembles communication data received from an
exchange, into a cell of fixed length, and then transmits the cell
to a cell transmission network, and which receives communication
data in the form of a cell, from the cell transmission network, and
thereafter disassembles the cell and transmits the resulting
communication data to the exchange, and a function of determining a
communication channel inside the equipment for use in connecting
the equipment with the exchange, on the basis of data contained in
a cell being processed within the equipment, comprising: a
passing-particular-equipment identification data insertion circuit
which inserts passing-particular-equipment identification data into
said communication data to be transmitted to said exchange, the
passing-particular-equipment identification data serving to
identify whether or not said communication data is in a relaying
state in which it is to be relayed by the particular equipment; a
passing-particular-equipm- ent identification data reception
circuit which receives said passing-particular-equipment
identification data from within the communication data received
from said exchange; a particular-communicatio- n-channel
identification data insertion circuit which inserts
particular-communication-channel identification data into said
communication data to be transmitted to said exchange, the
particular-communication-channel identification data indicating a
receiving communication channel of the cell assembly/disassembly
device which is processing the cell correspondent to said
communication data, when the received passing-particular-equipment
identification data indicates the relaying state; a
particular-communication-channel identification data reception
circuit which receives said particular-communication-channel
identification data from within said communication data received
from said exchange; a loop-back circuit which loops said cell
received from said cell transmission network by said cell
assembly/disassembly device, back to a side of said cell
transmission network, when said passing-particular-equipment
identification data which is contained in said cell
assembly/disassembly device being processing said cell
correspondent to said communication data received from said
exchange and which has been received together with said
communication data indicates said relaying state; and a cell route
alteration circuit which alters a route of said cell inside said
equipment in said cell assembly/disassembly device, in such a way
that the receiving communication channel of said cell to be
received from said cell transmission network is altered to one
which is indicated by said particular-communication-channel
identification data received from said exchange together with said
communication data.
4. A cell transmission equipment having a function of assembling
communication data received from an exchange, into a cell of fixed
length, switching the cell, and thereafter transmitting the cell to
a cell transmission network, a function of receiving communication
data in the form of a cell, from the cell transmission network,
switching the cell, and thereafter disassembling the cell and
transmitting the resulting communication data to the exchange, and
a function of determining a communication channel inside the
equipment for use in connecting the equipment with the exchange, on
the basis of data contained in a cell being processed within the
equipment, comprising: a passing-particular-equipment
identification data insertion circuit which inserts
passing-particular-equipment identification data into said
communication data to be transmitted to said exchange, the
passing-particular-equipment identification data serving to
identify whether or not said communication data is in a relaying
state in which it is to be relayed by the particular equipment; a
passing-particular-equipm- ent identification data reception
circuit which receives said passing-particular-equipment
identification data from within the communication data received
from said exchange; a particular-communicatio- n-channel
identification data insertion circuit which inserts
particular-communication-channel identification data into said
communication data to be transmitted to said exchange, the
particular-communication-channel identification data indicating a
communication channel of a cell correspondent to said communication
data, when the received passing-particular-equipment identification
data indicates the relaying state; a
particular-communication-channel identification data reception
circuit which receives said particular-communication-channel
identification data from within said communication data received
from said exchange; and a cell-switching-route alteration circuit
which alters a switching route of the cell inside said equipment,
on the basis of the received particular-communication-channel
identification data.
5. A cell transmission equipment having a function of assembling
communication data received from an exchange, into a cell of fixed
length, and then transmitting the cell to a cell transmission
network, a function of receiving communication data in the form of
a cell, from the cell transmission network, and thereafter
disassembling the cell and transmitting the resulting communication
data to the exchange, and a function of determining a communication
channel inside the equipment for use in connecting the equipment
with the exchange, on the basis of peculiar device identification
information for identifying each of data processing units included
in the equipment, comprising: a passing-particular-equipment
identification data insertion circuit which inserts
passing-particular-equipment identification data into said
communication data to be transmitted to said exchange, the
passing-particular-equipment identification data serving to
identify whether or not said communication data is in a relaying
state in which it is to be relayed by the particular equipment; a
passing-particular-equipm- ent identification data reception
circuit which receives said passing-particular-equipment
identification data from within the communication data received
from said exchange; a particular-communicatio- n-channel
identification data insertion circuit which inserts
particular-communication-channel identification data into said
communication data to be transmitted to said exchange, the
particular-communication-channel identification data being the
peculiar device identification information for identifying the data
processing unit in which said communication data to be transmitted
or a cell correspondent to said communication data is processed,
when the received passing-particular-equipment identification data
indicates the relaying state; a particular-communication-channel
identification data reception circuit which receives said
particular-communication-channel identification data from within
said communication data received from said exchange; and a cell
route alteration circuit which alters a route of the cell inside
said equipment, on the basis of the received
particular-communication-channel identification data.
6. A cell transmission equipment having a function of assembling
communication data received from an exchange, into a cell of fixed
length, switching the cell, and thereafter transmitting the cell to
a cell transmission network, a function of receiving communication
data in the form of a cell, from the cell transmission network,
switching the cell, and thereafter disassembling the cell and
transmitting the resulting communication data to the exchange, and
a function of determining a communication channel inside the
equipment for use in connecting the equipment with the exchange, on
the basis of data contained in a cell being processed within the
equipment, comprising: a passing-particular-equipment
identification data insertion circuit which inserts
passing-particular-equipment identification data into said
communication data to be transmitted to said exchange, the
passing-particular-equipment identification data serving to
identify whether or not said communication data is in a relaying
state in which it is to be relayed by the particular equipment; a
passing-particular-equipm- ent identification data reception
circuit which receives said passing-particular-equipment
identification data from within the communication data received
from said exchange; a particular-communicatio- n-channel
identification data insertion circuit which inserts
particular-communication-channel identification data into said
communication data to be transmitted to said exchange, the
particular-communication-channel identification data being the
peculiar device identification information for identifying a data
processing unit in which said communication data to be transmitted
or a cell correspondent to said communication data is processed,
when the received passing-particular-equipment identification data
indicates the relaying state; a particular-communication-channel
identification data reception circuit which receives said
particular-communication-channel identification data from within
said communication data received from said exchange; and a
cell-switching-route alteration circuit which alters a switching
route of the cell inside said equipment, on the basis of the
received particular-communication-channel identification data.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to technology for enhancing
the communication quality of communication data such as voice data,
when the data is relayed by transmission equipment in a network
which transmits fixed-length cells, such as an ATM (asynchronous
transfer mode) network.
[0003] 2. Description of the Related Art
[0004] In a case where TDM (time division multiplexing) equipment
are to be replaced with ATM equipment by exploiting a direction
selecting function based on exchanges which are used in an existing
network built up of the TDM equipment, it is requested that voice
of short delay and high quality having been obtained in the TDM
network be maintained even after the shift to the ATM network.
[0005] FIG. 1 is a diagram showing the architecture of a prior-art,
voice data relaying system which employs TDM equipment.
[0006] In each TDM equipment 1502 for connecting exchanges 1501 as
shown in FIG. 1, the delay (transmission delay) of data within the
equipment is slight. Therefore, even when the voice data is relayed
by the plurality of TDM equipment 1502, the delay thereof poses no
problem.
[0007] However, in a case where a CODEC (coder/decoder) block being
a device which codes and decodes voice data by the use of
compression technology is installed in each TDM equipment 1502 in
order to effectively utilize a transmission line, the relaying of
the voice data by the plurality of TDM equipment 1502 results in
degrading the communication quality of this voice data. The reason
therefor is that the operations of voice coding/decoding are
repeated for the number of times corresponding to the number of
times of relaying, to increase the degradation of a voice quality
attributed to the coding/decoding and the delay of the voice data
attributed to voice compression.
[0008] In the example of FIG. 1, the TDM equipment 1502(#2) to
which the exchange 1501(#2) of a relay station is connected between
the exchange 1501(#1) in which a telephone set having called out is
accommodated and the exchange 1501(#3) in which a telephone set to
call to is accommodated. On this occasion, the degradation of the
communication quality of the voice data increases in the two CODEC
blocks which are included in the TDM equipment 1502(#2).
[0009] There have been known various techniques collectively called
digital one-link relaying technology wherein, in order to prevent
the delay and the quality degradation which are incurred by the
coding/decoding of the voice data in the relaying office, the voice
data is not coded/decoded in the TDM equipment 1502(#2) serving as
the relaying office, whereby the number of times of the operations
of coding/decoding the voice data matches the number of times
corresponding to one link of the TDM equipment 1502.
[0010] In the example of FIG. 1, in a case where the exchange
1501(#2) does not operate as the relaying office, that is, in a
case where the exchange 1501(#2) is an office to which a telephone
set having called out is connected or an office to which a
telephone set to call in is connected, the CODEC block of the TDM
equipment 1502(#2) functions, so that the data which is transmitted
between the TDM equipment 1502(#2) and the exchange 1501(#2)
becomes decoded original voice data.
[0011] On the other hand, in a case where the exchange 1501(#2)
operates as the relaying office, the CODEC blocks of the TDM
equipment 1502(#2) do not function, so that the data which is
relayed and transmitted in both ways between the TDM equipment
1502(#2) and the exchange 1501(#2) remains coded voice data.
[0012] In this case, the data which is transmitted bears
passing-particular-equipment identification data for identifying
whether or not the exchange 1501(#2) is to operate as the relaying
office (that is, whether or not the particular equipment is to be
passed). The TDM equipment 1502(#2) judges the
passing-particular-equipment identification data, whereby the CODEC
blocks are controlled to be valid/invalid.
[0013] Owing to such digital one-link relaying technology, voice
communications of high quality can be realized in the TDM network
even when a plurality of relaying equipment exist.
[0014] Meanwhile, in recent years, it has come to be eagerly
requested that a TDM network be replaced with an ATM network for
the purposes of heightening the transmission speed of
communications and enlarging the traffic volume thereof.
[0015] FIG. 2 is a diagram showing the architecture of a prior-art,
voice data switching system which employs ATM equipment 1601
substituted for the TDM equipment 1502 in the TDM network depicted
in FIG. 1.
[0016] Referring to FIG. 2, a CLAD (cell assembly/disassembly)
block installed in each ATM equipment 1601 is a device which
assembles voice data into an ATM cell and which disassembles an ATM
cell into voice data.
[0017] Besides, an ATM cell switch block installed in each ATM
equipment 1601 operates as illustrated in FIG. 3. More
specifically, the ATM cell switch block analyzes destination
information affixed to the header part of the ATM cell which is
entered from a port lying on the side of the CLAD block, so as to
switch the ATM cell in the direction of a destination, and it
alters the destination information of the header part to one
corresponding to the next relaying destination and then delivers
the resulting ATM cell to a port lying on the side of a
transmission line. Also, regarding the ATM cell which is reversely
entered from a port lying on the side of the transmission line, the
ATM cell switch block analyzes destination information affixed to
the header part of the entered ATM cell so as to switch this cell,
and it alters the destination information of the header part and
then delivers the resulting ATM cell to a port lying on the side of
the CODEC block as corresponds to the next destination.
[0018] In general, a data transmission rate at the input/output
port of an ATM cell switch block to which a CLAD block is connected
is very high, so that the input/output port can process data of
large traffic volume (ATM cell). In contrast, since data to be
processed by the CLAD block is only voice data, a data processing
rate in the CLAD block is much lower than the data transmission
rate at the input/output port of the ATM cell switch block. In
order to effectively use the data transmission capacity of the
input/output port of the ATM cell switch block, therefore, a
plurality of CLAD blocks are often connected to one input/output
port.
[0019] In the architecture depicted in FIG. 2, the ATM equipment
1601 form paths which are always fixed, among the respective
exchanges 1501.
[0020] With the prior art illustrated in FIG. 2, however, the
process for assembling or disassembling the ATM cell for the voice
data is required in the CLAD block within each ATM equipment 1601
even in the case of adopting the vocal digital one-link relaying
technology which employs the passing-particular-equipment
identification data or the like and which has been realized in the
TDM network. The prior art therefore has the problem that delays
ascribable to the cell assembly/disassembly in the two CLAD blocks
within the ATM equipment 1601 to which the exchange 1501(#2) of the
relaying office is connected are accumulated, resulting in the
increase of a delay in the understanding of the voice data.
[0021] FIG. 4 is a diagram showing the architecture of another
prior-art, voice data relaying system which employs ATM equipment
1601 substituted for the TDM equipment 1502 in the TDM network
depicted in FIG. 1.
[0022] The architecture in FIG. 4 differs from the architecture in
FIG. 2 in the point that a signalling termination block for
receiving and analyzing the signalling information of voice is
installed in each ATM equipment 1601, and that a dynamic path
extending from a calling office (the exchange 1501 in which a
telephone set having called out is accommodated) to a final called
office (the exchange 1501 in which a telephone set to call in is
accommodated) is formed in the ATM network by the controls of the
signalling termination blocks.
[0023] With the architecture illustrated in FIG. 4, the ATM
equipment 1601(#5) does not operate, in itself, as a relaying
office for transferring voice data to-be-relayed to the exchange
1501(#4), but it directly switches the ATM cell of the voice data
to-be-relayed toward the final called office by means of the ATM
cell switch block.
[0024] In the above prior art shown in FIG. 4, the ATM cell for the
voice data to-be-relayed is not assembled/disassembled by the CLAD
in the ATM equipment 1601(#5) which operates as a relaying office
for relaying the voice data, and hence, a delay ascribable to the
cell assembly/disassembly does not occur in this relaying
office.
[0025] The prior art shown in FIG. 4, however, has the problem that
the signalling termination block needs to be installed in each ATM
equipment 1601, and that management data for deciding the final
called office on the basis of the signalling information is
required.
[0026] Besides, with the prior art shown in FIG. 4, the main
constituents of the relaying become the ATM equipment 1601, not the
exchanges 1501, in the case where the conventional TDM network has
been altered to the ATM network. This leads to the problem that the
network topology among the exchanges 1501 existing on the network
must be changed to one which is conscious of the ATM equipment
1601.
SUMMARY OF THE INVENTION
[0027] The present invention has been made with the background
stated above, and it has for its object to incarnate a cell
transmission network in which the network topology among exchanges
as formed in a conventional TDM network can be exploited as it is,
and in which the numbers of times of coding/decoding and cell
assembling/disassembling operations for voice data match the
numbers of times corresponding to one link of transmission
equipment.
[0028] The first aspect of the present invention is premised on a
cell transmission equipment (an ATM equipment 102) having a
function of assembling communication data received from an exchange
(101), into a cell (an ATM cell) of fixed length, and then
transmitting the cell to a cell transmission network (an ATM
network), a function of receiving communication data in the form of
a cell, from the cell transmission network, and thereafter
disassembling the cell and transmitting the resulting communication
data to the exchange, and a function of determining a communication
channel inside the equipment for use in connecting the equipment
with the exchange, on the basis of data contained in a cell being
processed within the equipment.
[0029] First, a passing-particular-equipment identification data
insertion circuit (a frame generation unit 1014) inserts
passing-particular-equipme- nt identification data into the
communication data to be transmitted to the exchange, the
passing-particular-equipment identification data serving to
identify whether or not the communication data is in a relaying
state in which it is to be relayed by the particular equipment.
[0030] A passing-particular-equipment identification data reception
circuit (a frame synchronization detection unit 1017) receives the
passing-particular-equipment identification data from within the
communication data received from the exchange.
[0031] A particular-communication-channel identification data
insertion circuit (an MUX unit 1004) inserts
particular-communication-channel identification data into the
communication data to be transmitted to the exchange, the
particular-communication-channel identification data indicating a
communication channel of a cell correspondent to the communication
data, when the received passing-particular-equipment identification
data indicates the relaying state.
[0032] A particular-communication-channel identification data
reception circuit (a particular-voice-channel identification data
detection unit 1006) receives the particular-communication-channel
identification data from within the communication data received
from the exchange.
[0033] A cell route alteration circuit (a CLAD block 104 or an ATM
cell switch block 105) alters the route of the cell inside the
equipment, on the basis of the received
particular-communication-channel identification data.
[0034] Owing to the above construction in the first aspect of the
present invention, data processing units (for example, the CLAD
blocks 104) opposing to each other can exchange the items of
information on the communication channels of the cells which they
are respectively processing, therebetween via the exchange.
Therefore, the route of the cell inside the equipment is altered on
the basis of the information, whereby the cell left intact can be
relayed toward its destination without causing the communication
data itself to pass through the exchange. As a result, the numbers
of times of coding/decoding and cell assembling/disassembling
operations for the voice data match the numbers of times
corresponding to one link of transmission equipment.
[0035] In this case, the cell transmission equipment alters the
relaying path of the cell on the basis of only the control of the
particular equipment itself, and the exchange operates so as to
receive the corresponding communication data from the data
processing unit of the cell transmission equipment and to directly
relay the received data to the opposing data processing unit
included in the particular equipment, that is, the exchange
executes the ordinary relaying operation. Therefore, the first
aspect of the present invention has the feature that the network
topology among the exchanges existing on the network need not be
changed.
[0036] The second aspect of the present invention is premised on a
cell transmission equipment (an ATM equipment 102) having a cell
assembly/disassembly device (CLAD block 104) which assembles
communication data received from an exchange (101), into a cell (an
ATM cell) of fixed length, and then transmits the cell to a cell
transmission network (an ATM network), and which receives
communication data in the form of a cell, from the cell
transmission network, and thereafter disassembles the cell and
transmits the resulting communication data to the exchange, and a
function of determining a communication channel inside the
equipment for use in connecting the equipment with the exchange, on
the basis of data contained in a cell being processed within the
equipment.
[0037] In the first place, the second aspect of the present
invention comprises a passing-particular-equipment identification
data insertion circuit, a passing-particular-equipment
identification data reception circuit, and a
particular-communication-channel identification data reception
circuit which are similar to those in the first aspect of the
present invention.
[0038] Next, a particular-communication-channel identification data
insertion circuit (an MUX unit 1004) inserts
particular-communication-cha- nnel identification data into the
communication data to be transmitted to the exchange, the
particular-communication-channel identification data indicating the
transmitting communication channel of the cell assembly/disassembly
device (the transmission address value of the particular CLAD)
which is processing a cell correspondent to the communication data,
when the received passing-particular-equipment identification data
indicates the relaying state.
[0039] A loop-back circuit (an SEL unit 1008) loops the cell
received from the cell transmission network by the cell
assembly/disassembly device, back to the side of the cell
transmission network, when the passing-particular-equipment
identification data which is contained in the cell
assembly/disassembly device being processing the cell correspondent
to the communication data received from the exchange and which has
been received together with the communication data indicates the
relaying state.
[0040] A cell route alteration circuit (an address/SEL control unit
1010, an address setting unit 1009) alters the route of the cell
inside the equipment in the cell assembly/disassembly device, in
such a way that the transmitting communication channel of the cell
to be looped back is altered to one which is indicated by the
particular-communication-channel identification data received from
the exchange together with the communication data.
[0041] The third aspect of the present invention is premised on the
same cell transmission equipment as in the second aspect of the
present invention.
[0042] In the first place, the third aspect of the present
invention comprises a passing-particular-equipment identification
data insertion circuit, a passing-particular-equipment
identification data reception circuit, a
particular-communication-channel identification data reception
circuit, and a loop-back circuit which are similar to those in the
second aspect of the present invention.
[0043] Next, a particular-communication-channel identification data
insertion circuit (an MUX unit 1004) inserts
particular-communication-cha- nnel identification data into the
communication data to be transmitted to the exchange, the
particular-communication-channel identification data indicating a
receiving communication channel of the cell assembly/disassembly
device (the reception address value of the particular CLAD) which
is processing the cell correspondent to the communication data,
when the received passing-particular-equipment identification data
indicates the relaying state.
[0044] Besides, a cell route alteration circuit (a selective
reception unit 1002, an address/SEL control unit 1010) alters the
route of the cell inside the equipment in the cell
assembly/disassembly device, in such a way that the receiving
communication channel of the cell to be received from the cell
transmission network is altered to one which is indicated by the
particular-communication-channel identification data received from
the exchange together with the communication data.
[0045] Owing to the above construction in the second or third
aspect of the present invention, the cell assembly/disassembly
devices opposing to each other can exchange the items of
information on the transmission and reception channels of the cells
which they are respectively processing, therebetween via the
exchange. Therefore, the cell received from the cell transmission
network can be looped back to the cell transmission network and be
relayed on the basis of the information, without executing the cell
assembling/disassembling processing in each cell
assembly/disassembly device. As a result, the numbers of times of
coding/decoding and cell assembling/disassembling operations for
the voice data match the numbers of times corresponding to one link
of transmission equipment.
[0046] Also, likewise to the first aspect of the present invention,
the second or third aspect thereof has the feature that the network
topology among the exchanges existing on the network need not be
changed.
[0047] The fourth aspect of the present invention is premised on a
cell transmission equipment (an ATM equipment 102) having a
function of assembling communication data received from an exchange
(101), into a cell (an ATM cell) of fixed length, switching the
cell, and thereafter transmitting the cell to a cell transmission
network (an ATM network), a function of receiving communication
data in the form of a cell, from the cell transmission network,
switching the cell, and thereafter disassembling the cell and
transmitting the resulting communication data to the exchange, and
a function of determining a communication channel inside the
equipment for use in connecting the equipment with the exchange, on
the basis of data contained in a cell being processed within the
equipment.
[0048] In the first place, the fourth aspect of the present
invention comprises a passing-particular-equipment identification
data insertion circuit, a passing-particular-equipment
identification data reception circuit, a
particular-communication-channel identification data insertion
circuit, and a particular-communication-channel identification data
reception circuit which are similar to those in the first aspect of
the present invention.
[0049] In addition, a cell-switching-route alteration circuit (a
routing control unit 1205) alters the switching route of the cell
inside the equipment, on the basis of the received
particular-communication-channel identification data.
[0050] Owing to the above construction in the fourth aspect of the
present invention, data processing units (for example, the CLAD
blocks 104) opposing to each other can exchange the items of
information on the transmission and reception channels of the cells
which they are respectively processing, therebetween via the
exchange. Therefore, the switching route of the cell is altered in
a cell switching circuit (an ATM cell switch block 105) on the
basis of the information, whereby the cell can be directly relayed.
As a result, the numbers of times of coding/decoding and cell
assembling/disassembling operations for the voice data match the
numbers of times corresponding to one link of transmission
equipment.
[0051] Also, likewise to the first aspect of the present invention,
the fourth aspect thereof has the feature that the network topology
among the exchanges existing on the network need not be
changed.
[0052] The fifth aspect of the present invention is premised on a
cell transmission equipment (an ATM equipment 102) having a
function of assembling communication data received from an exchange
(101), into a cell (an ATM cell) of fixed length, and then
transmitting the cell to a cell transmission network (an ATM
network), a function of receiving communication data in the form of
a cell, from the cell transmission network, and thereafter
disassembling the cell and transmitting the resulting communication
data to the exchange, and a function of determining a communication
channel inside the equipment for use in connecting the equipment
with the exchange, on the basis of peculiar device identification
information for identifying each of data processing units included
in the equipment.
[0053] In the first place, the fifth aspect of the present
invention comprises a passing-particular-equipment identification
data insertion circuit, a passing-particular-equipment
identification data reception circuit, and a
particular-communication-channel identification data reception
circuit which are similar to those in the first aspect of the
present invention.
[0054] Next, a particular-communication-channel identification data
insertion circuit (an MUX unit 1004) inserts
particular-communication-cha- nnel identification data into the
communication data to be transmitted to the exchange, the
particular-communication-channel identification data being the
peculiar device identification information (the peculiar number
value of the particular CLAD) for identifying the data processing
unit (the CLAD block 104) in which the communication data to be
transmitted or a cell correspondent to the communication data is
processed, when the received passing-particular-equipment
identification data indicates the relaying state.
[0055] Besides, a cell route alteration circuit (the CLAD block
104, an ATM cell switch block 105) alters the route of the cell
inside the equipment, on the basis of the received
particular-communication-channel identification data.
[0056] Owing to the above construction in the fifth aspect of the
present invention, the data processing units (for example, the CLAD
blocks 104) opposing to each other can exchange the items of
peculiar device identification information for identifying the
respective data processing units, therebetween via the exchange.
Therefore, the route of the cell inside the equipment is altered on
the basis of the information, whereby the cell left intact can be
relayed toward its destination without causing the communication
data itself to pass through the exchange. As a result, the numbers
of times of coding/decoding and cell assembling/disassembling
operations for the voice data match the numbers of times
corresponding to one link of transmission equipment.
[0057] Also, likewise to the first aspect of the present invention,
the fifth aspect thereof has the feature that the network topology
among the exchanges existing on the network need not be
changed.
[0058] The sixth aspect of the present invention is premised on a
cell transmission equipment (an ATM equipment 102) having a
function of assembling communication data received from an exchange
(101), into a cell (an ATM cell) of fixed length, switching the
cell, and thereafter transmitting the cell to a cell transmission
network (an ATM network), a function of receiving communication
data in the form of a cell, from the cell transmission network,
switching the cell, and thereafter disassembling the cell and
transmitting the resulting communication data to the exchange, and
a function of determining a communication channel inside the
equipment for use in connecting the equipment with the exchange, on
the basis of data contained in a cell being processed within the
equipment.
[0059] In the first place, the sixth aspect of the present
invention comprises a passing-particular-equipment identification
data insertion circuit, a passing-particular-equipment
identification data reception circuit, a
particular-communication-channel identification data insertion
circuit, and a particular-communication-channel identification data
reception circuit which are similar to those in the fifth aspect of
the present invention.
[0060] In addition, a cell-switching-route alteration circuit (a
routing control unit 1205) alters the switching route of the cell
inside the equipment, on the basis of the received
particular-communication-channel identification data.
[0061] Owing to the above construction in the sixth aspect of the
present invention, the data processing units (for example, CLAD
blocks 104) opposing to each other can exchange the items of
peculiar device identification information for identifying the
respective data processing units, therebetween via the exchange.
Therefore, the switching route of the cell is altered in a cell
switching circuit (an ATM cell switch block 105) on the basis of
the information, whereby the cell can be directly relayed. As a
result, the numbers of times of coding/decoding and cell
assembling/disassembling operations for the voice data match the
numbers of times corresponding to one link of transmission
equipment.
[0062] Also, likewise to the first aspect of the present invention,
the sixth aspect thereof has the feature that the network topology
among the exchanges existing on the network need not be
changed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0063] Other objects or features of the present invention will be
readily understood by one skilled in the art from the description
of the preferred embodiments thereof when read in conjunction with
the accompanying drawings wherein:
[0064] FIG. 1 is a diagram showing the architecture of a prior-art,
voice data relaying system which employs TDM equipment;
[0065] FIG. 2 is a diagram showing the architecture of a prior-art,
voice data relaying system which employs ATM equipment (and in
which TDM technology is applied as it is);
[0066] FIG. 3 is a diagram for explaining the principle of ATM
switching;
[0067] FIG. 4 is a diagram showing the architecture of a prior-art,
voice data relaying system which employs ATM equipment (and in
which signalling termination is introduced);
[0068] FIG. 5 is a diagram showing a first fundamental architecture
which is applicable to the respective preferred embodiments of the
present invention;
[0069] FIG. 6 is a diagram showing a second fundamental
architecture which is applicable to the respective preferred
embodiments of the present invention;
[0070] FIG. 7 is a diagram showing the architecture of the first
preferred embodiment of the present invention (in the ordinary
state thereof);
[0071] FIG. 8 is a diagram showing the architecture of the first
preferred embodiment of the present invention (in the relaying
state thereof);
[0072] FIG. 9 is a diagram showing the architecture of the second
preferred embodiment of the present invention (in the ordinary
state thereof);
[0073] FIG. 10 is a diagram showing the architecture of the second
preferred embodiment of the present invention (in the relaying
state thereof);
[0074] FIG. 11 is a diagram showing the architecture of the third
preferred embodiment of the present invention (in the ordinary
state thereof);
[0075] FIG. 12 is a diagram showing the architecture of the third
preferred embodiment of the present invention (in the relaying
state thereof);
[0076] FIG. 13 is a diagram showing the architecture of the fourth
preferred embodiment of the present invention;
[0077] FIG. 14 is a diagram showing the architecture of a first
practicable system which corresponds to the first and second
preferred embodiments of the present invention;
[0078] FIG. 15 is a diagram showing the architecture of a second
practicable system which corresponds to the first, second and
fourth preferred embodiments of the present invention;
[0079] FIG. 16 is a diagram showing the architecture of a third
practicable system which corresponds to the third preferred
embodiment of the present invention;
[0080] FIG. 17 is a diagram showing the architecture of a fourth
practicable system which corresponds to the third preferred
embodiment of the present invention; and
[0081] FIG. 18 is a diagram showing the frame format of
passing-particular-equipment identification data.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0082] Now, the preferred embodiments of the present invention will
be described in detail with reference to the drawings.
First Fundamental Architecture Applicable to the Respective
Preferred Embodiments
[0083] FIG. 5 is a diagram showing a first fundamental architecture
which is applicable to the respective preferred embodiments of the
present invention.
[0084] In the architecture illustrated in FIG. 5, ATM equipment 102
at #1-#3 function as relaying networks of respective exchanges 101
at #1-#3, and they form semifixed paths (permanent virtual
channels) among the exchanges 101.
[0085] In this case, the transit trunks among the plurality of ATM
equipment 102 are connected by an ATM dedicated line, an
installation consisting of the exchange 101 and the ATM equipment
102 associated therewith is located in, for example, each branch
office of an enterprise, and the ATM equipment 102 in the
respective branch offices are connected by the ATM dedicated line,
whereby a WAN (wide area network) can be formed. That is, each ATM
equipment 102 can be caused to function as an ATM-WAN node which
realizes WAN communications.
[0086] Also, when existing STM (synchronous transfer mode) private
lines with which multiple access services etc. are utilizable are
employed as the transit trunks, the ATM equipment 102 can be so
constructed that ATM cells to be communicated among the ATM
equipment 102 are transmitted using the time division channel or
channels of one or more of the STM private lines as predetermined.
Such an architecture makes it possible to merge ATM multiplexing
technology which can flexibly cope with traffic fluctuations and
which is suited for transmission of high efficiency, with TDM (time
division multiplexing) technology which can reliably guarantee a
high transmission line quality.
[0087] Here in this case, each ATM equipment 102 functioning as the
ATM-WAN node can process voice data which the exchange 101
processes. Moreover, it can relay LAN traffic etc. exhibiting high
degrees of burst, by connecting various sorts of TDM equipment or
LAN equipment.
[0088] Regarding functions which are especially relevant to the
present invention, the ATM equipment 102 includes a CODEC
(coder/decoder) block 103 which codes and compresses original voice
data inputted from the exchange 101 and then outputs the resulting
data to the side of an ATM cell switch block 105, and which
conversely decodes original voice data from coded voice data
inputted from the side of the ATM cell switch block 105 and then
outputs the resulting data to the exchange 101.
[0089] Also, the ATM equipment 102 includes a CLAD (cell
assembly/disassembly) block 104 which assembles the coded voice
data inputted from the CODEC block 103, into an ATM cell and then
outputs the cell to the ATM cell switch block 105, and which
conversely disassembles an ATM cell inputted from the ATM cell
switch block 105, into the coded voice data.
[0090] The ATM cell switch block 105 which is further included in
the ATM equipment 102, executes the same switching process as
explained with reference to FIG. 3 before, for an ATM cell which is
communicated between this ATM equipment 102 and the exchange 101 or
ATM equipment 102 connected in adjacency thereto.
[0091] Besides, the ATM equipment 102 includes a transmission line
block 106 (a transmission line termination device) which terminates
the ATM line connecting this ATM equipment 102 with the adjacent
ATM equipment 102.
[0092] Here, the blocks 103 - 106 included in the ATM equipment 102
realize the autonomous routing (self-routing) of an ATM cell inside
the ATM equipment 102, on the basis of destination information
called VPI/VCI (a virtual path identifier/a virtual channel
identifier) which is set in the header part of the ATM cell.
[0093] In, for example, the ATM equipment 102(#2), a certain ATM
cell which has been transferred from the adjacent ATM equipment
102(#1) has a VPI/VCI value set in its header part, the VPI/VCI
value corresponding to a transmission address (11) previously set
for the line block 106(#1) connected to a port A, and this ATM cell
is delivered from the line block 106(#1) to the port A of the ATM
cell switch block 105.
[0094] Upon judging that the header part of the ATM cell received
at the port A bears the VPI/VCI value corresponding to the
transmission address (11) of the line block 106(#1), the ATM cell
switch block 105 rewrites the VPI/VCI value of the header part of
the ATM cell, into a value corresponding to the reception address
(1) of the CLAD block 104(#1) connected to a port B, on the basis
of previous setting. Thereafter, the resulting ATM cell is
transferred into the ATM cell switch block 105.
[0095] The ATM cell switch block 105 autonomously routes the above
ATM cell so as to be transferred to the port B, on the basis of the
port number information of the port A and the VPI/VCI value
contained in the header part of the ATM cell.
[0096] The CLAD block 104(#1) connected to the port B accepts
thereinto the ATM cell received from the ATM cell switch block 105
only in a case where it has judged that the header part of this ATM
cell bears the VPI/VCI value corresponding to the reception address
(1) set for the particular device 104(#1) beforehand.
[0097] Likewise, in the ATM equipment 102(#2), a certain ATM cell
which has been transferred from the adjacent ATM equipment 102(#3)
has a VPI/VCI value set in its header part, the VPI/VCI value
corresponding to a transmission address (13) previously set for the
line block 106(#2) connected to a port C, and this ATM cell is
delivered from the line block 106(#2) to the port C of the ATM cell
switch block 105.
[0098] Upon judging that the header part of the ATM cell received
at the port C bears the VPI/VCI value corresponding to the
transmission address (13) of the line block 106(#2), the ATM cell
switch block 105 rewrites the VPI/VCI value of the header part of
the ATM cell, into a value corresponding to the reception address
(3) of the CLAD block 104(#2) connected to the port B, on the basis
of previous setting. Thereafter, the resulting ATM cell is
transferred into the ATM cell switch block 105.
[0099] The ATM cell switch block 105 autonomously routes the above
ATM cell so as to be transferred to the port B, on the basis of the
port number information of the port C and the VPI/VCI value affixed
to the header part of the ATM cell.
[0100] The CLAD block 104(#2) connected to the port B accepts
thereinto the ATM cell received from the ATM cell switch block 105
only in a case where it has judged that the header part of this ATM
cell bears the VPI/VCI value corresponding to the reception address
(3) set for the particular device 104(#2) beforehand.
[0101] On the other hand, in the ATM equipment 102(#2), an ATM cell
to be delivered from the CLAD block 104(#1) has a VPI/VCI value set
in its header part, the VPI/VCI value corresponding to a
transmission address (2) previously set for the particular device
104(#1), and this ATM cell is delivered from the CLAD block 104(#1)
to the port B of the ATM cell switch block 105.
[0102] Upon judging that the header part of the ATM cell received
at the port B bears the VPI/VCI value corresponding to the
transmission address (2) of the CLAD block 104(#1), the ATM cell
switch block 105 rewrites the VPI/VCI value of the header part of
the ATM cell, into a value corresponding to the reception address
(12) of the line block 106(#1) connected to the port A, on the
basis of previous setting. Thereafter, the resulting ATM cell is
transferred into the ATM cell switch block 105.
[0103] The ATM cell switch block 105 autonomously routes the above
ATM cell so as to be transferred to the port A, on the basis of the
port number information of the port B and the VPI/VCI value affixed
to the header part of the ATM cell.
[0104] The line block 106(#1) connected to the port A accepts
thereinto the ATM cell received from the ATM cell switch block 105
only in a case where it has judged that the header part of this ATM
cell bears the VPI/VCI value corresponding to the reception address
(12) set for the particular device 106(#1) beforehand.
Subsequently, the line block 106(#1) delivers the accepted ATM cell
to the ATM line with which the adjacent ATM equipment 102(#1) is
connected.
[0105] Likewise, in the ATM equipment 102(#2), an ATM cell to be
delivered from the CLAD block 104(#2) has a VPI/VCI value set in
its header part, the VPI/VCI value corresponding to a transmission
address (4) previously set for the particular device 104(#2), and
this ATM cell is delivered from the CLAD block 104(#2) to the port
B of the ATM cell switch block 105.
[0106] Upon judging that the header part of the ATM cell received
at the port B bears the VPI/VCI value corresponding to the
transmission address (4) of the CLAD block 104(#2), the ATM cell
switch block 105 rewrites the VPI/VCI value of the header part of
the ATM cell, into a value corresponding to the reception address
(14) of the line block 106(#2) connected to the port C, on the
basis of previous setting. Thereafter, the resulting ATM cell is
transferred into the ATM cell switch block 105.
[0107] The ATM cell switch block 105 autonomously routes the above
ATM cell so as to be transferred to the port C, on the basis of the
port number information of the port B and the VPI/VCI value affixed
to the header part of the ATM cell.
[0108] The line block 106(#2) connected to the port C accepts
thereinto the ATM cell received from the ATM cell switch block 105
only in a case where it has judged that the header part of this ATM
cell bears the VPI/VCI value corresponding to the reception address
(14) set for the particular device 106(#2) beforehand.
Subsequently, the line block 106(#2) delivers the accepted ATM cell
to the ATM line with which the adjacent ATM equipment 102(#3) is
connected.
[0109] In the above way, in the ATM equipment 102(#2), the
following four semifixed paths (permanent virtual paths) are
formed:
Path 1
[0110] Port A, Transmission address (11) of Line block 106(#1)
[0111] .fwdarw.Port B, Reception address (1) of CLAD block
104(#1)
Path 2
[0112] .fwdarw.Port B, Transmission address (2) of CLAD block
104(#1)
[0113] .fwdarw.Port A, Reception address (12) of Line block
106(#1)
Path 3
[0114] .fwdarw.Port B, Transmission address (4) of CLAD block
104(#2)
[0115] .fwdarw.Port C, Reception address (14) of Line block
106(#2)
Path 4
[0116] Port C, Transmission address (13) of Line block 106(#2)
[0117] .fwdarw.Port B, Reception address (3) of CLAD block
104(#2)
[0118] Now, by way of example, in a case where voice is to be sent
from a telephone set #1 connected to the exchange 101(#1), to a
telephone set #3 connected to the exchange 101(#2), the ATM
equipment 102(#2) transfers an ATM cell correspondent to the voice
by the use of the above path 1. Besides, the CLAD block 104(#1)
included in the ATM equipment 102(#2) converts the ATM cell into
coded voice data on the first time-division channel. Further, the
CODEC block 103(#1) included in the ATM equipment 102(#2) restores
original voice data from the coded voice data of the first
time-division channel. The original voice data is transferred to
the exchange 101(#2) by the use of the first time-division channel
until it arrives at the telephone set #3.
[0119] To the contrary, in a case where voice is to be sent from
the telephone set #3 connected to the exchange 101(#2), to the
telephone set #1 connected to the exchange 101(#1), the ATM
equipment 102(#2) transfers an ATM cell correspondent to the voice
by the use of the above path 2. In this case, the CODEC block
103(#1) included in the ATM equipment 102(#2) codes and compresses
original voice data received from the second time-division channel
which pairs with and extends reversely to the first time-division
channel. Further, the CLAD block 104(#1) included in the ATM
equipment 102(#2) converts the coded voice data into an ATM cell.
The ATM cell is transferred from the ATM cell switch block 105
included in the ATM equipment 102(#2), to the ATM equipment 102(#1)
via the line block 106(#1), and it is converted into the coded
voice data of a predetermined time-division channel by the CLAD
block which is included in the ATM equipment 102(#1) and which is
not especially shown. Besides, the CODEC block which is included in
the ATM equipment 102(#1) and which is not especially shown
restores original voice data from the coded voice data of the above
time-division channel. The original voice data is transferred to
the exchange 101(#1) by the use of the above time-division channel
until it arrives at the telephone set #1.
[0120] Also in a case where telephonic communications are to be
established between a telephone set #4 connected to the exchange
101(#3) and the telephone set #3 connected to the exchange 101(#2),
the ATM equipment 102(#2) executes transfer processing similar to
the above, by the use of the CLAD block 104(#2) and CODEC block
103(#2) which are included in this equipment 102(#2).
[0121] Next, there will be described a case where telephonic
communications are to be established between the telephone set #1
connected to the exchange 101(#1) and the telephone set #4
connected to the exchange 101(#3).
[0122] In this case, voice data is transferred along the path of
Telephone set #1.rarw..fwdarw.Exchange 101(#1).rarw..fwdarw.ATM
equipment 102(#1).rarw..fwdarw.ATM equipment
102(#2).rarw..fwdarw.ATM equipment 102(#3).rarw..fwdarw.Exchange
101(#3).rarw..fwdarw.Telephone set #4.
[0123] More specifically, it is a feature relevant to the present
invention that, in each of the preferred embodiments of the present
invention, the ATM equipment 102(#2) alters a path inside the
particular equipment 102(#2) so as to relay the voice data in the
form of an ATM cell left intact, in lieu of the exchange
101(#2).
[0124] As a result, the ATM equipment 102(#2) is permitted to relay
the voice data in the form of the ATM cell as it is, by executing
neither the cell assembling/disassembling operation nor the
coding/decoding operation, and the digital one-link relaying of
voice is realized.
[0125] In this case, the ATM equipment 102(#2) alters the relaying
path on the basis of only the control of the particular equipment
itself. The exchange 101(#2) operates so as to receive data on a
corresponding time-division channel from the first CODEC block 103
included in the ATM equipment 102(#2), and to directly relay the
data to the opposing second CODEC block 103 included in the
particular equipment 102(#2). That is, the exchange 101(#2)
executes the ordinary relaying operation. This brings forth the
feature that the network topology among the exchanges 101 existing
on the network need not be changed.
[0126] Here, in a case where such a relaying operation has become
necessary, the two CODEC blocks 103 in the ATM equipment 102(#2)
mutually exchange items of information on the
transmission/reception addresses of ATM cells in the respective
CODEC blocks 103, unlike the voice data, by utilizing the time
division channels which are connected via the exchange 101(#2). On
the basis of the information exchange, the relaying paths are
altered in the ATM cell switch block 105 or two CODEC blocks 103
included in the ATM equipment 102(#2). This is the great feature
relevant to the present invention.
[0127] In order to realize the relaying control, in a case where
the first CLAD block 104 included in the ATM equipment 102(#2) or
the first CODEC block 103 connected thereto is to deliver the voice
data toward the exchange 101(#2) on the first time-division
channel, it superposes passing-particular-equipment identification
data on voice data on the basis of previous call setting, the
identification data serving to identify whether or not the voice
data is to be relayed by the ATM equipment 102(#2) to which the
particular device 104 or 103 belongs.
[0128] After having been delivered from the first CLAD block 104 or
first CODEC block 103 included in the ATM equipment 102(#2), the
passing-particular-equipment identification data is relayed by the
exchange 101(#2) and is received by the second CLAD block 104
located on the opposite side to the first CLAD block 104 within the
ATM equipment 102(#2) or by the second CODEC block 103 connected
thereto.
[0129] Besides, when the passing-particular-equipment
identification data superposed on the received voice data has been
judged as indicating that the voice data on the first time-division
channel along which the identification data has been transmitted in
is to be relayed by the particular ATM equipment 102(#2), the
second CODEC block 103 stops the coding/decoding operation.
[0130] Also, using the second time-division channel which pairs
with and extends reversely to the first time-division channel
mentioned above, the second CLAD block 104 or the second CODEC
block 103 delivers passing-particular-equipment identification data
which indicates that voice data on the second time-division channel
is to be similarly relayed by the particular ATM equipment
102(#2).
[0131] Simultaneously, using the second time-division channel
mentioned above, the second CLAD block 104 delivers a transmission
address or reception address set for the particular device 104
beforehand, as particular-voice-channel identification data.
[0132] The above passing-particular-equipment identification data
and particular-voice-channel identification data on the second
time-division channel are relayed by the exchange 101(#2), and are
transferred to the first CLAD block 104 or first CODEC block 103
which is included in the ATM equipment 102(#2).
[0133] When the passing-particular-equipment identification data on
the second time-division channel has been first received, the first
CODEC block 103 stops the coding/decoding operation.
[0134] Subsequently, the particular-voice-channel identification
data on the second time-division channel passes through the first
CODEC block 103 having stopped the coding/decoding operation and is
received by the first CLAD block 104.
[0135] Besides, using the first time-division channel mentioned
above, the first CLAD block 104 delivers a transmission address or
reception address set for the particular device 104 beforehand, as
particular-voice-channel identification data.
[0136] The particular-voice-channel identification data on the
first time-division channel passes through the first CODEC block
103 having stopped the coding/decoding operation, it is thereafter
relayed by the exchange 101(#2), it further passes through the
second CODEC block 103 having stopped the coding/decoding
operation, and it is received by the second CLAD block 104 included
in the ATM equipment 102(#2).
[0137] In the above way, in the case where the voice data on the
first time-division channel and the voice data on the second
time-division channel pairing with and extending reversely to the
first time-division channel are to be relayed by the ATM equipment
102(#2), the two CLAD blocks 104(#1 and #2) in the ATM equipment
102(#2) mutually exchange the particular-voice-channel
identification data being the items of information on the
transmission/reception addresses of the ATM cells in the respective
CODEC blocks 103, unlike the voice data, by utilizing the first and
second time-division channels which are connected via the exchange
101(#2).
[0138] Herein, on the basis of the particular-voice-channel
identification data, the two CODEC blocks 103(#1 and #2) or the ATM
cell switch block 105 which are/is included in the ATM equipment
102(#2) alter/alters the relaying paths so that the respective ATM
cells corresponding to the first and second time-division channels
may be directly transferred along the route of ATM equipment
102(#1).rarw..fwdarw.ATM equipment 102(#2).rarw..fwdarw.ATM
equipment 102(#3).
[0139] Practicable alteration controls for the switching paths will
be described later as to the first-third preferred embodiments.
Second Fundamental Architecture Applicable to the Respective
Preferred Embodiments
[0140] FIG. 6 is a diagram showing a second fundamental
architecture which is applicable to the respective preferred
embodiments of the present invention.
[0141] The point of difference of the architecture in FIG. 6 from
the architecture in FIG. 5 is that, in the foregoing case where the
voice data on the first time-division channel and the voice data on
the second time-division channel pairing with and extending
reversely to the first time-division channel are to be relayed by
the ATM equipment 102(#2), the two CLAD blocks 104(#1 and #2) in
the ATM equipment 102(#2) mutually exchange peculiar device numbers
previously set for the respective CODEC blocks 103, as the
particular-voice-channel identification data replacing the items of
information on the transmission/reception addresses of the ATM
cells in the respective CODEC blocks 103, by utilizing the first
and second time-division channels which are connected via the
exchange 101(#2).
[0142] The peculiar device numbers are bestowed on the CLAD blocks
104, and are exchanged as the particular-voice-channel
identification data. Thus, it is permitted to identify the ATM
cells to-be-relayed which are delivered and accepted between the
ATM cell switch block 105 and the respective CLAD blocks 104, and
to alter the relaying paths in the same way as in the case of the
first fundamental architecture shown in FIG. 5.
First Preferred Embodiment of the Present Invention
[0143] FIGS. 7 and 8 are diagrams showing the construction of the
first preferred embodiment of the present invention as based on the
first fundamental architecture depicted in FIG. 5.
[0144] First, FIG. 7 illustrates an ordinary state being a control
state correspondent to the path as to which the ATM equipment
102(#2) does not perform the relaying operation.
[0145] The ordinary state corresponds to, for example, the state of
the ATM equipment 102(#2) in the case where telephonic
communications are held between the telephone set #1 connected to
the exchange 101(#1) and the telephone set #3 connected to the
exchange 101(#2).
[0146] As stated before with reference to FIG. 5, in the case where
voice is sent from the telephone set #1 connected to the exchange
101(#1), to the telephone set #3 connected to the exchange 101(#2),
an ATM cell corresponding to the voice is received by the
transmission line block 106(#1) included in the ATM equipment
102(#2), via the ATM equipment 102(#1). Thereafter, using the path
1 stated in conjunction with FIG. 5, the ATM cell is transferred to
the CLAD block 104(#1) included in the ATM equipment 102(#2), via
the ATM cell switch block 105 included therein.
[0147] Subsequently, the CLAD block 104(#1) selectively receives
the above ATM cell (step S1 indicated within a square 201 in FIG.
7), followed by the conversion of the ATM cell into coded voice
data on the first time-division channel (cell disassembly at a step
S2 indicated within the square 201 in FIG. 7).
[0148] Further, the CODEC block 103(#1) included in the ATM
equipment 102(#2) restores original voice data from the coded voice
data on the first time-division channel.
[0149] Using the first time-division channel, the original voice
data is transferred to the exchange 101(#2) and arrives at the
telephone set #3.
[0150] To the contrary, in the case where voice is sent from the
telephone set #3 connected to the exchange 101(#2), to the
telephone set #1 connected to the exchange 101(#1), the CODEC block
103(#1) included in the ATM equipment 102(#2) accepts original
voice data transmitted by the telephone set #3, from the exchange
101(#2), by the use of the second predetermined time-division
channel pairing with and extending reversely to the above first
time-division channel, and it codes and compresses the accepted
original voice data.
[0151] Subsequently, the CLAD block 104(#1) included in the ATM
equipment 102(#2) converts the coded voice data into an ATM cell
(step S3 indicated within the square 201 in FIG. 7). The ATM cell
has a VPI/VCI value affixed to its header part, the VPI/VCI value
corresponding to the transmission address (2) of the CLAD block
104(#1). The resulting ATM cell is outputted from the CLAD block
104(#1) to the ATM cell switch block 105 included in the ATM
equipment 102(#2) (steps S4.fwdarw.S5 indicated within the square
201 in FIG. 7).
[0152] The ATM cell is further transferred from the ATM cell switch
block 105 to the ATM equipment 102(#1) via the line block 106(#1),
and it is converted into the coded voice data of a predetermined
time-division channel by the CLAD block which is included in the
equipment 102(#1) and which is not especially shown.
[0153] Besides, the CODEC block which is included in the ATM
equipment 102(#1) and which is not especially shown restores the
original voice data from the coded voice data of the time-division
channel. Using this time-division channel, the original voice data
is transferred to the exchange 101(#1) and arrives at the telephone
set #1.
[0154] Also in the ordinary state in which telephonic
communications are held between the telephone set #4 connected to
the exchange 101(#3) and the telephone set #3 connected to the
exchange 101(#2), the ATM equipment 102(#2) executes transfer
processing similar to the above, by the use of the CLAD block
104(#2) and CODEC block 103(#2) which are included in this
equipment 102(#2).
[0155] Next, FIG. 8 illustrates a relaying state being a control
state correspondent to the path as to which the ATM equipment
102(#2) performs the relaying operation.
[0156] The relaying state corresponds to, for example, the state of
the ATM equipment 102(#2) in the case where telephonic
communications are held between the telephone set #1 connected to
the exchange 101(#1) and the telephone set #4 connected to the
exchange 101(#3).
[0157] In the case where the ATM equipment 102(#2) has fallen into
the state in which voice data on the first time-division channel
and voice data on the second time-division channel pairing with and
extending reversely to the first time-division channel are to be
relayed by this ATM equipment 102(#2), the processing explained
before with reference to FIG. 5 is executed. More specifically, the
first CLAD block 104 included in the ATM equipment 102(#2) or the
first CODEC block 103 connected to the block 104 as has detected
the relaying state superposes passing-particular-equipment
identification data on the voice data, the identification data
indicating that the voice data is to be relayed by the ATM
equipment 102(#2) to which the particular device 104 or 103
belongs, at the time of sending the voice data toward the exchange
101(#2) on the first time-division channel.
[0158] By the way, in the ordinary state illustrated in FIG. 7, the
voice data on the time division channel bears superposed
passing-particular-equipment identification data which indicates
that the voice data is not to be relayed by the ATM equipment
102(#2) to which the particular device 104 or 103 belongs.
[0159] As explained before with reference to FIG. 5, after the
items of passing-particular-equipment identification data have been
successively detected by the two CODEC blocks 103 or two CLAD
blocks 104 included in the ATM equipment 102(#2), the two CODEC
blocks 103 included in the ATM equipment 102(#2) stop the
coding/decoding operations.
[0160] Simultaneously, as explained before with reference to FIG.
5, the two CLAD blocks 104 included in the ATM equipment 102(#2)
mutually exchange the particular-voice-channel identification data
being the items of information on the transmission addresses of the
ATM cells in the respective CODEC blocks 103, unlike the voice
data, by utilizing the first and second time-division channels
which are connected via the exchange 101(#2).
[0161] In the example of FIG. 8, the CLAD block 104(#1) notifies
the transmission address (2) of the ATM cell lying in the
particular device 104(#1), to the CLAD block 104(#2) by utilizing
the first time-division channel which is connected with the CLAD
block 104(#2) via the exchange 101(#2).
[0162] On the other hand, also the CLAD block 104(#2) notifies the
transmission address (4) of the ATM cell lying in the particular
device 104(#2), to the CLAD block 104(#1) by utilizing the second
time-division channel which is connected with the CLAD block
104(#1) via the exchange 101(#2).
[0163] When, after the reception of the transmission address (4)
from the CLAD block 104(#2), the CLAD block 104(#1) has received an
ATM cell whose header part bears a VPI/VCI value corresponding to
the reception address (1), via the ATM cell switch block 105 from
the transmission line block 106(#1), it loops the received ATM cell
back to a route for delivering this cell to the ATM cell switch
block 105, without disassembling this cell (LOOP at steps
S1.fwdarw.S4 indicated within the square 201 in FIG. 7).
[0164] Simultaneously, the CLAD block 104(#1) alters the VPI/VCI
value which is set in the header part of the ATM cell turned back
in the above way, from a value correspondent to the transmission
address (2) to a value correspondent to the transmission address
(4), and it sends the resulting ATM cell toward the ATM cell switch
block 105 (steps S4.fwdarw.S5 indicated within the square 201 in
FIG. 7).
[0165] On the other hand, when, after the reception of the
transmission address (2) from the CLAD block 104(#1), the CLAD
block 104(#2) has received an ATM cell whose header part bears a
VPI/VCI value corresponding to the reception address (3), via the
ATM cell switch block 105 from the transmission line block 106(#2),
it loops the received ATM cell back to a route for delivering this
cell to the ATM cell switch block 105.
[0166] Simultaneously, the CLAD block 104(#2) alters the VPI/VCI
value which is set in the header part of the ATM cell turned back
in the above way, from a value correspondent to the transmission
address (4) to a value correspondent to the transmission address
(2), and it sends the resulting ATM cell toward the ATM cell switch
block 105.
[0167] As explained before with reference to FIG. 5, when the ATM
cell switch block 105 has judged that the header part of the ATM
cell received at the port B bears the VPI/VCI value corresponding
to the transmission address (4), it rewrites the VPI/VCI value of
the header part of the ATM cell, into a value corresponding to the
reception address (14) of the line block 106(#2) connected to the
port C, on the basis of previous setting. Thereafter, the resulting
ATM cell is transferred into the ATM cell switch block 105.
Besides, the ATM cell switch block 105 autonomously routes the
above ATM cell so as to be transferred to the port C, on the basis
of the port number information of the port B and the VPI/VCI value
affixed to the header part of the ATM cell.
[0168] As also explained before with reference to FIG. 5, when the
ATM cell switch block 105 has judged that the header part of the
ATM cell received at the port B bears the VPI/VCI value
corresponding to the transmission address (2), it rewrites the
VPI/VCI value of the header part of the ATM cell, into a value
corresponding to the reception address (12) of the line block
106(#1) connected to the port A, on the basis of previous setting.
Thereafter, the resulting ATM cell is transferred into the ATM cell
switch block 105. Besides, the ATM cell switch block 105
autonomously routes the above ATM cell so as to be transferred to
the port A, on the basis of the port number information of the port
B and the VPI/VCI value affixed to the header part of the ATM
cell.
[0169] As the result of the above control operation, the ATM cell
which contains the voice data directed to the exchange 101(#3) and
which has been received from the ATM equipment 102(#1) by the line
block 106(#1) included in the ATM equipment 102(#2) is received by
the CLAD block 104(#1) included in the ATM equipment 102(#2), via
the ATM cell switch block 105 included therein, and it is turned
back in the CLAD block 104(#1). Further, the ATM cell is directly
transferred to the line block 106(#2) included in the ATM equipment
102(#2), via the ATM cell switch block 105 included therein, and it
is transmitted from the line block 106(#2) toward the ATM equipment
102(#3).
[0170] To the contrary, the ATM cell which contains the voice data
directed to the exchange 101(#1) and which has been received from
the ATM equipment 102(#3) by the line block 106(#2) included in the
ATM equipment 102(#2) is received by the CLAD block 104(#2)
included in the ATM equipment 102(#2), via the ATM cell switch
block 105 included therein, and it is turned back in the CLAD block
104(#2). Further, the ATM cell is directly transferred to the line
block 106(#1) included in the ATM equipment 102(#2), via the ATM
cell switch block 105 included therein, and it is transmitted from
the line block 106(#1) toward the ATM equipment 102(#1).
[0171] As a result, the ATM equipment 102(#2) is permitted to relay
the voice data in the form of the ATM cell as it is, by executing
neither the cell assembling/disassembling operation nor the
coding/decoding operation, and the digital one-link relaying of
voice is realized.
[0172] In this case, as explained before with reference to FIG. 5,
the exchange 101(#2) executes the ordinary relaying operation so
that the data on the first or second time-division channel may be
communicated between the first and second CODEC blocks 103 which
are included in the ATM equipment 102(#2). This preferred
embodiment therefore has the feature that the network topology
among the exchanges 101 existing on the network need not be
changed.
Second Preferred Embodiment of the Present Invention
[0173] FIGS. 9 and 10 are diagrams showing the construction of the
second preferred embodiment of the present invention as based on
the first fundamental architecture depicted in FIG. 5.
[0174] First, FIG. 9 illustrates an ordinary state being a control
state correspondent to the path as to which the ATM equipment
102(#2) does not perform the relaying operation, and it is similar
to FIG. 7 in the first preferred embodiment of the present
invention.
[0175] Next, FIG. 10 illustrates a relaying state being a control
state correspondent to the path as to which the ATM equipment
102(#2) performs the relaying operation.
[0176] Likewise to the case of FIG. 8 in the first preferred
embodiment of the present invention, the relaying state corresponds
to, for example, the state of the ATM equipment 102(#2) in the case
where telephonic communications are held between the telephone set
#1 connected to the exchange 101(#1) and the telephone set #4
connected to the exchange 101(#3).
[0177] The point of difference of the construction in FIG. 10 from
the construction in FIG. 8 is that, after the detection of the
passing-particular-equipment identification data indicating the
relaying state, the two CLAD blocks 104 in the ATM equipment
102(#2) mutually exchange items of information on the reception
addresses of ATM cells lying in the respective CODEC blocks 103,
unlike the transmission addresses thereof, as the
particular-voice-channel identification data.
[0178] More specifically, in the example of FIG. 10, the CLAD block
104(#1) notifies the reception address (1) of the ATM cell lying in
the particular device 104(#1), to the CLAD block 104(#2) by
utilizing the first time-division channel which is connected with
the CLAD block 104(#2) via the exchange 101(#2).
[0179] On the other hand, also the CLAD block 104(#2) notifies the
reception address (3) of the ATM cell lying in the particular
device 104(#2), to the CLAD block 104(#1) by utilizing the second
time-division channel which is connected with the CLAD block
104(#1) via the exchange 101(#2).
[0180] Upon receiving the reception address (3) from the CLAD block
104(#2), the CLAD block 104(#1) alters the setting of an ATM cell
to be received by the particular device 104(#1), so as to receive
the ATM cell whose header part bears a VPI/VCI value corresponding
to the reception address (3), not the ATM cell whose header part
bears a VPI/VCI value corresponding to the reception address
(1).
[0181] Simultaneously, the CLAD block 104(#1) loops the ATM cell
received by itself, back to a route for delivering this cell to the
ATM cell switch block 105, without executing a process for
converting this cell into coded voice data (LOOP at steps
S1.fwdarw.S4 indicated within a square 201 in FIG. 9).
[0182] Besides, the ATM cell turned back has its header part
endowed with a VPI/VCI value corresponding to the transmission
address (2) set beforehand and is delivered to the ATM cell switch
block 105, from which it is transferred to the line block
106(#1).
[0183] On the other hand, upon receiving the reception address (1)
from the CLAD block 104(#1), the CLAD block 104(#2) alters the
setting of an ATM cell to be received by the particular device
104(#2), so as to receive the ATM cell whose header part bears a
VPI/VCI value corresponding to the reception address (1), not the
ATM cell whose header part bears a VPI/VCI value corresponding to
the reception address (3).
[0184] Simultaneously, the CLAD block 104(#2) loops the ATM cell
received by itself, back to a route for delivering this cell to the
ATM cell switch block 105, without executing a process for
converting this cell into coded voice data.
[0185] Besides, the ATM cell turned back has its header part
endowed with a VPI/VCI value corresponding to the transmission
address (4) set beforehand and is delivered to the ATM cell switch
block 105, from which it is transferred to the line block
106(#2).
[0186] As explained before with reference to FIG. 5, when the ATM
cell switch block 105 has judged that the header part of the ATM
cell received at the port A bears the VPI/VCI value corresponding
to the transmission address (11) of the line block 106(#1), it
rewrites the VPI/VCI value of the header part of the ATM cell, into
a value corresponding to the reception address (1) at the port B,
on the basis of previous setting. Thereafter, the resulting ATM
cell is transferred into the ATM cell switch block 105. Besides,
the ATM cell switch block 105 autonomously routes the above ATM
cell so as to be transferred to the port B, on the basis of the
port number information of the port A and the VPI/VCI value affixed
to the header part of the ATM cell.
[0187] As also explained before with reference to FIG. 5, when the
ATM cell switch block 105 has judged that the header part of the
ATM cell received at the port C bears the VPI/VCI value
corresponding to the transmission address (13) of the line block
106(#2), it rewrites the VPI/VCI value of the header part of the
ATM cell, into a value corresponding to the reception address (3)
at the port B, on the basis of previous setting. Thereafter, the
resulting ATM cell is transferred into the ATM cell switch block
105. Besides, the ATM cell switch block 105 autonomously routes the
above ATM cell so as to be transferred to the port B, on the basis
of the port number information of the port C and the VPI/VCI value
affixed to the header part of the ATM cell.
[0188] As the result of the above control operation, the ATM cell
which contains the voice data directed to the exchange 101(#3) and
which has been received from the ATM equipment 102(#1) by the line
block 106(#1) included in the ATM equipment 102(#2) is directly
received by the CLAD block 104(#2) included in the ATM equipment
102(#2), via the ATM cell switch block 105 included therein, and it
is turned back in the CLAD block 104(#2). Further, the ATM cell is
transferred to the line block 106(#2) included in the ATM equipment
102(#2), via the ATM cell switch block 105 included therein, and it
is transmitted from the line block 106(#2) toward the ATM equipment
102(#3).
[0189] To the contrary, the ATM cell which contains the voice data
directed to the exchange 101(#1) and which has been received from
the ATM equipment 102(#3) by the line block 106(#2) included in the
ATM equipment 102(#2) is directly received by the CLAD block
104(#1) included in the ATM equipment 102(#2), via the ATM cell
switch block 105 included therein, and it is turned back in the
CLAD block 104(#1). Further, the ATM cell is transferred to the
line block 106(#1) included in the ATM equipment 102(#2), via the
ATM cell switch block 105 included therein, and it is transmitted
from the line block 106(#1) toward the ATM equipment 102(#1).
[0190] As a result, as in the case of the first preferred
embodiment of the present invention, the ATM equipment 102(#2) is
permitted to switch the voice data in the form of the ATM cell as
it is, by executing neither the cell assembling/disassembling
operation nor the coding/decoding operation, and the digital
one-link relaying of voice is realized.
Third Preferred Embodiment of the Present Invention
[0191] FIGS. 11 and 12 are diagrams showing the construction of the
third preferred embodiment of the present invention as based on the
first or second fundamental architecture depicted in FIG. 5 or
6.
[0192] First, FIG. 11 illustrates an ordinary state being a control
state correspondent to the path as to which the ATM equipment
102(#2) does not perform the relaying operation, and it is similar
to FIG. 7 in the first preferred embodiment of the present
invention.
[0193] Next, FIG. 12 illustrates a relaying state being a control
state correspondent to the path as to which the ATM equipment
102(#2) performs the relaying operation.
[0194] Likewise to the case of FIG. 8 in the first preferred
embodiment of the present invention, the relaying state corresponds
to, for example, the state of the ATM equipment 102(#2) in the case
where telephonic communications are held between the telephone set
#1 connected to the exchange 101(#1) and the telephone set #4
connected to the exchange 101(#3).
[0195] The point of difference of the construction in FIG. 12 from
the construction in FIG. 8 is that, after the detection of the
passing-particular-equipment identification data indicating the
relaying state, the two CLAD blocks 104 in the ATM equipment
102(#2) mutually exchange items of information on the transmission
or reception addresses of ATM cells lying in the respective CODEC
blocks 103 or items of information on the peculiar device numbers
of the respective CODEC blocks 103, as the particular-voice-channel
identification data, whereupon the respective CODEC blocks 103 do
not perform the loop-back controls, but the relaying paths are
altered so that the ATM cell switch block 105 may directly switch
the pertinent ATM cells between the line blocks 106(#1) and
106(#2).
[0196] As a result, as in the cases of the first and second
preferred embodiments of the present invention, the ATM equipment
102(#2) is permitted to switch the voice data in the form of the
ATM cell as it is, by executing neither the cell
assembling/disassembling operation nor the coding/decoding
operation, and the digital one-link relaying of voice is
realized.
Fourth Preferred Embodiment of the Present Invention
[0197] FIG. 13 is a diagram showing the construction of the fourth
preferred embodiment of the present invention as based on the first
or second fundamental architecture depicted in FIG. 5 or 6.
[0198] With the construction of the fourth preferred embodiment of
the present invention, the functions of any of the first through
third preferred embodiments described above are fulfilled, but the
functions of inserting/detecting the passing-particular-equipment
identification data, the functions of inserting/detecting the
particular-voice-channel identification data, and the function of
altering a relaying path as explained before are installed and
closed in a CLAD device 901 having no CODEC blocks 103 of its own,
and the CODEC blocks 103 are separated as an exchange termination
device 902.
[0199] Alternatively, although not shown in FIG. 13, a relaying
system may well be so constructed that the above functions are
installed and closed in a CLAD device which has neither the CODEC
blocks 103 nor an ATM cell switch block 105 of its own.
[0200] Owing to such a construction, the switching of ATM cells can
be actualized by the CLAD device only.
[0201] It is also possible to realize an ATM equipment or a CLAD
device which is connected to an exchange not requiring any CODEC
block 103, and which has the function of altering a switching path
relevant to the present invention.
[0202] There will now be described those practicable system
architectures of the present invention which are more detailed
architectures based on the foregoing preferred embodiments of the
present invention.
First Practicable System Architecture Corresponding to the
First/Second Preferred Embodiments of the Present Invention
[0203] FIG. 14 is a block diagram showing the first practicable
system architecture which concerns the CLAD block 104 and the CODEC
block 103 corresponding to the foregoing first preferred embodiment
of the present invention illustrated in FIGS. 7 and 8 or the
foregoing second preferred embodiment of the present invention
illustrated in FIGS. 9 and 10.
[0204] First, the CLAD block 104 will be described.
[0205] An ATM cell switch block I/F unit 1001 controls the
interface of signals which are communicated between the ATM cell
switch block 105 and the CLAD block 104 as shown in FIG. 5,
etc.
[0206] A selective reception unit 1002 analyzes the header parts of
ATM cells delivered from the ATM cell switch block 105, and it
selects and receives only ATM cells which bear a VPI/VCI value
corresponding to a reception address set by an address/SEL control
unit 1010.
[0207] A cell disassembly unit 1003 disassembles the ATM cell
delivered from the ATM cell switch block 105, and it derives only
coded voice data set in the payload part of the ATM cell and sends
the derived data toward the CODEC block 103.
[0208] An MUX unit 1004 multiplexes the transmission address value
of the particular CLAD device (in the foregoing case of the first
preferred embodiment of the present invention) or the reception
address value of the particular CLAD device (in the foregoing case
of the second preferred embodiment of the present invention) as is
particular-CLAD set information stored in a set information storage
unit 1011, as the particular-voice-channel identification data onto
the output of the coded voice data delivered from the cell
disassembly unit 1003. A data format here is as shown in FIG. 14,
and data employing four bits H0-H3 is transmitted.
[0209] A CODEC block I/F unit 1005 controls the interface of
signals which are communicated between the CODEC block 103 and the
CLAD block 104.
[0210] A particular-voice-channel identification data detection
unit 1006 begins to operate at the point of time at which it has
been notified of the detection of a frame synchronization state
correspondent to passing-particular-equipment identification data
indicative of a relaying state by a frame synchronization detection
unit 1017 to be explained later as is included in the CODEC block
103. Herein, the detection unit 1006 detects
particular-voice-channel identification data notified via the
exchange 101(#2) (refer to FIG. 5) by the opposing CLAD block 104
(opposing-channel address information notification).
[0211] A cell assembly unit 1007 assembles coded voice data
received from the CODEC block 103, into an ATM cell.
[0212] An SEL unit 1008 selects either the ATM cell assembled by
the cell assembly unit 1007 or the ATM cell looped back from the
selective reception unit 1002.
[0213] An address setting unit 1009 sets the VPI/VCI value of the
header part of the ATM cell outputted from the SEL unit 1008, to a
value corresponding to the transmission address set by the
address/SEL control unit 1010.
[0214] In a case where the functions corresponding to the first
preferred embodiment of the present invention as explained before
are fulfilled, the address/SEL control unit 1010 sets in the
selective reception unit 1002 the reception address value of the
particular CLAD device notified as the particular-CLAD set
information notification by the set information storage unit 1011.
Also, the address/SEL control unit 1010 selects either the
transmission address value of the particular CLAD device notified
as the particular-CLAD set information notification by the set
information storage unit 1011 or transmission address value being
the particular-voice-channel identification data notified as the
opposing-channel address information notification by the
particular-voice-channel identification data detection unit 1006,
on the basis of the detected state of the particular-voice-channel
identification data in the particular-voice-channel identification
data detection unit 1006, and it sets the selected transmission
address value in the address setting unit 1009.
[0215] On the other hand, in a case where the functions
corresponding to the second preferred embodiment of the present
invention as explained before are fulfilled, the address/SEL
control unit 1010 sets in the address setting unit 1009 the
transmission address value of the particular CLAD device notified
as the particular-CLAD set information notification by the set
information storage unit 1011. Also, the address/SEL control unit
1010 selects either the reception address value of the particular
CLAD device notified as the particular-CLAD set information
notification by the set information storage unit 1011 or reception
address value being the particular-voice-channel identification
data notified as the opposing-channel address information
notification by the particular-voice-channel identification data
detection unit 1006, on the basis of the detected state of the
particular-voice-channel identification data in the
particular-voice-channel identification data detection unit 1006,
and it sets the selected reception address value in the selective
reception unit 1002.
[0216] The set information storage unit 1011 stores therein the
reception address value and transmission address value of the
particular CLAD device assigned beforehand by an equipment control
block, not especially shown, for controlling the operation of the
whole ATM equipment 102.
[0217] First, a CLAD block I/F unit 1020 controls the interface of
signals which are communicated between the CODEC block 103 and the
CLAD block 104.
[0218] A decoding unit 1012 decodes original voice data from the
coded voice data which has been received from the CLAD block
104.
[0219] On condition that an SEL unit 1013 is not notified of the
detection of the frame synchronization state correspondent to the
passing-particular-equipment identification data indicative of the
relaying state by the frame synchronization detection unit 1017 to
be explained later, it selects the original voice data outputted
from the decoding unit 1012 and transmits the selected data toward
the exchange 101(#2) (refer to FIG. 5). In contrast, on condition
that the SEL unit 1013 is notified of the detection of the frame
synchronization state by the frame synchronization detection unit
1017, it selects the particular-voice-channel identification data
delivered from the CLAD block 104 and transmits the selected data
toward the exchange 101(#2) (refer to FIG. 5).
[0220] An MUX unit 1015 superposes a bit sequence being the
passing-particular-equipment identification data indicative of the
relaying state as generated by a frame generation unit 1014, on the
original voice data or particular-voice-channel identification data
outputted from the SEL unit 1013, and it transmits the resulting
data toward the exchange 101(#2) (refer to FIG. 5).
[0221] An exchange connection block I/F unit 1016 controls the
interface of signals which are communicated between the CODEC block
103 and the exchange 101(#2) (refer to FIG. 5).
[0222] The frame synchronization detection unit 1017 detects the
bit sequence being the passing-particular-equipment identification
data indicative of the relaying state, as the frame synchronization
state from the original voice data or particular-voice-channel
identification data received from the exchange 101.
[0223] A coding unit 1018 codes and compresses the original voice
data received from the exchange 101, and it transmits the resulting
coded voice data toward the CLAD block 104.
[0224] On condition that an SEL unit 1019 is not notified of the
detection of the frame synchronization state correspondent to the
passing-particular-equipment identification data indicative of the
relaying state by the frame synchronization detection unit 1017, it
selects the coded voice data outputted from the coding unit 1018
and transmits the selected data toward the CLAD block 104. In
contrast, on condition that the SEL unit 1019 is notified of the
detection of the frame synchronization state by the frame
synchronization detection unit 1017, it selects the
particular-voice-channel identification data notified via the
exchange 101(#2) (refer to FIG. 5) by the opposing CLAD block 104
and transmits the selected data toward the CLAD block 104.
[0225] FIG. 18 is a diagram showing the frame format of the bit
sequence of the passing-particular-equipment identification data
which is generated by the frame generation unit 1014 included in
the CLAD block 104, and which is superposed on the voice data.
[0226] On the time division channel, the voice data are transmitted
in units of sample data of 8 bits consisting of bits 0-7, and the
rate of sampling is 8 kHz. Consequently, one time-division channel
can transmit PCM voice data having a transmission rate of 8
bits.times.8000=64 kilobits/second.
[0227] After eleven voice sample data have been sent as illustrated
at (b) in FIG. 18 on the time division channel which becomes the
relaying state, the frame generation unit 1014 invalidates the
least significant bit (bit 0 ) of the twelfth voice sample data as
illustrated at (a) in FIG. 18, and it superposes a value 1 on the
bit position as a passing-particular-equipment identification data
bit F.
[0228] Subsequently, after fifteen voice sample data have been sent
on the time division channel, the frame generation unit 1014
invalidates the least significant bit of the sixteenth voice sample
data as illustrated at (a) in FIG. 18, and it superposes a value 0
on the bit position as the passing-particular-equipment
identification data bit F.
[0229] Further, after eleven voice sample data have been sent again
on the time division channel, the frame generation unit 1014
invalidates the least significant bit of the twelfth voice sample
data, and it superposes the value 1 on the bit position as the
passing-particular-equipment identification data bit F.
[0230] In this way, the passing-particular-equipment identification
data indicative of the relaying state are actualized as the frame
bit sequence which alternates as 0 .fwdarw.(waiting for 12
samples).fwdarw.1.fwdarw.(w- aiting for 16 samples).fwdarw.0
.fwdarw.(waiting for 12 samples).fwdarw.1. On this occasion, the
interval of the frame bits to be inserted is held at a sufficiently
large one such as 12 samples or 16 samples. Therefore, the
degradation of the quality of voice to be transmitted can be
suppressed to the minimum, while at the same time, reliable pull-in
can be attained.
[0231] When the frame synchronization detection unit 1017 has
detected the above alterations of 0 and 1 ninety-six times by way
of example, it recognizes the frame synchronization state
corresponding to the passing-particular-equipment identification
data indicative of the relaying state. In contrast, when the frame
synchronization detection unit 1017 is not detecting the frame
synchronization state, it recognizes that the
passing-particular-equipment identification data indicative of a
non-relaying state are being sent.
[0232] With the above construction of the CLAD block 104 as well as
the CODEC block 103 shown in FIG. 14, in the ordinary state (the
foregoing state shown in FIG. 7 or FIG. 9) in which the frame
synchronization detection unit 1017 included in the CODEC block 103
is not detecting the frame synchronization state, controls to be
described below are performed on the basis of the detection output
of the detection unit 1017 and the control state in the address/SEL
control unit 1010.
[0233] First, the selective reception unit 1002 in the CLAD block
104 is controlled so as to receive only the ATM cell whose header
part bears the VPI/VCI value corresponding to the reception address
value of the particular CLAD device stored in the set information
storage unit 1011.
[0234] In addition, the SEL unit 1008 in the CLAD block 104 is
controlled so as to select the ATM cell which has been assembled by
the cell assembly unit 1007.
[0235] Besides, the address setting unit 1009 in the CLAD block 104
is controlled so as to set the VPI/VCI value corresponding to the
transmission address value of the particular CLAD device stored in
the set information storage unit 1011, in the header part of the
ATM cell which is to be sent to the ATM cell switch block 105.
[0236] Further, the MUX unit 1004 in the CLAD block 104 outputs
only the coded voice data which is delivered from the cell
disassembly unit 1003.
[0237] On the other hand, the SEL unit 1013 in the CODEC block 103
is controlled so as to select the original voice data which has
been decoded by the decoding unit 1012.
[0238] In addition, the MUX unit 1015 in the CODEC block 103
outputs only the original voice data which is delivered from the
SEL unit 1013.
[0239] Further, the SEL unit 1019 is controlled so as to select the
coded voice data which is outputted from the coding unit 1018.
[0240] Next, in the relaying state (the foregoing state shown in
FIG. 8 or FIG. 10) in which the frame synchronization detection
unit 1017 included in the CODEC block 103 is detecting the frame
synchronization state, controls to be described below are performed
on the basis of the detection output of the detection unit 1017,
the detection result in the particular-voice-channel identification
data detection unit 1006 and the control state in the address/SEL
control unit 1010.
[0241] First, in the case where the functions corresponding to the
first preferred embodiment of the present invention as explained
before are fulfilled, the selective reception unit 1002 in the CLAD
block 104 is controlled so as to receive only the ATM cell whose
header part bears the VPI/VCI value corresponding to the reception
address value of the particular CLAD device stored in the set
information storage unit 1011.
[0242] In addition, the SEL unit 1008 in the CLAD block 104 is
controlled so as to select the ATM cell which is looped back from
the selective reception unit 1002.
[0243] Besides, the address setting unit 1009 in the CLAD block 104
is controlled so as to set the VPI/VCI value corresponding to the
transmission address value of the opposing CLAD block 104 as is
notified as the particular-voice-channel identification data by the
particular-voice-channel identification data detection unit 1006,
in the header part of the ATM cell which is to be sent to the ATM
cell switch block 105.
[0244] Further, the MUX unit 1004 in the CLAD block 104 outputs as
the particular-voice-channel identification data the transmission
address value of the particular CLAD device as is the
particular-CLAD set information stored in the set information
storage unit 1011.
[0245] On the other hand, the SEL unit 1013 in the CODEC block 103
is controlled so as to select the particular-voice-channel
identification data outputted from the CLAD block 104, without
selecting the output of the decoding unit 1012.
[0246] Besides, in the MUX unit 1015 included in the CLAD block
104, the frame bit sequence which has been generated by the frame
generation unit 1014 and which corresponds to the
passing-particular-equipment identification data indicative of the
relaying state is superposed on the particular-voice-channel
identification data delivered from the SEL unit 1013.
[0247] Further, the SEL unit 1019 is controlled so as to select the
particular-voice-channel identification data notified via the
exchange 101(#2) by the opposing CLAD block 104, without selecting
the output of the coding unit 1018.
[0248] Next, in the case where the functions corresponding to the
second preferred embodiment of the present invention as explained
before are fulfilled, the selective reception unit 1002 in the CLAD
block 104 is controlled so as to receive only the ATM cell whose
header part bears the VPI/VCI value corresponding to the reception
address value of the opposing CLAD block 104 as is notified as the
particular-voice-channel identification data by the
particular-voice-channel identification data detection unit
1006.
[0249] In addition, the SEL unit 1008 in the CLAD block 104 is
controlled so as to select the ATM cell which is looped back from
the selective reception unit 1002.
[0250] Besides, the address setting unit 1009 in the CLAD block 104
is controlled so as to set the VPI/VCI value corresponding to the
transmission address value of the particular CLAD device as is
stored in the set information storage unit 1011, in the header part
of the ATM cell which is to be sent to the ATM cell switch block
105.
[0251] Further, the MUX unit 1004 in the CLAD block 104 outputs as
the particular-voice-channel identification data the reception
address value of the particular CLAD device as is the
particular-CLAD set information stored in the set information
storage unit 1011.
[0252] On the other hand, the SEL unit 1013 in the CODEC block 103
is controlled so as to select the particular-voice-channel
identification data outputted from the CLAD block 104, without
selecting the output of the decoding unit 1012.
[0253] Besides, in the MUX unit 1015 included in the CLAD block
104, the frame bit sequence which has been generated by the frame
generation unit 1014 and which corresponds to the
passing-particular-equipment identification data indicative of the
relaying state is superposed on the particular-voice-channel
identification data delivered from the SEL unit 1013.
[0254] Further, the SEL unit 1019 is controlled so as to select the
particular-voice-channel identification data notified via the
exchange 101(#2) by the opposing CLAD block 104, without selecting
the output of the coding unit 1018.
[0255] Owing to the above control operations, the foregoing
functions of the first or second preferred embodiment of the
present invention are realized.
Second Practicable System Architecture Corresponding to the
First/Second/Fourth Preferred Embodiments of the Present
Invention
[0256] FIG. 15 is a block diagram showing the second practicable
system architecture which concerns the CLAD block 104 corresponding
to the foregoing first preferred embodiment of the present
invention illustrated in FIGS. 7 and 8, or the foregoing second
preferred embodiment of the present invention illustrated in FIGS.
9 and 10, and the foregoing fourth preferred embodiment of the
present invention illustrated in FIG. 13.
[0257] In the architecture shown in FIG. 15, the functions of the
frame generation unit 1014 and the MUX unit 1015 and the function
of the frame synchronization detection unit 1017 as are installed
within the CODEC block 103 in the architecture shown in FIG. 14 are
intensively packaged within the CLAD block 104.
[0258] Owing to such a construction, the switching of ATM cells can
be actualized by an ATM equipment having no CODEC blocks 103 or by
the CLAD device only, as explained before in conjunction with the
fourth preferred embodiment of the present invention.
Third Practicable System Architecture Corresponding to the Third
Preferred Embodiment of the Present Invention
[0259] FIG. 16 is a block diagram showing the third practicable
system architecture which concerns the ATM cell switch block 105
and the CLAD block 104 corresponding to the foregoing third
preferred embodiment of the present invention illustrated in FIGS.
11 and 12.
[0260] Although the construction of the CLAD block 104 is almost
the same as in the case of the first practicable system
architecture shown in FIG. 14, a particular-CLAD peculiar number
value is set and stored in the set information storage unit 1011 by
an equipment control block not especially shown, and it is
outputted as particular-voice-channel identification data.
[0261] Besides, a switching path is altered in the ATM cell switch
block 105, not in the CLAD block 104, as explained before in
conjunction with the third preferred embodiment of the present
invention illustrated in FIGS. 11 and 12. Therefore, the SEL unit
1008 and the address/SEL control unit 1010 for performing the
loop-back control as shown in FIG. 14 are not installed in the
construction shown in FIG. 16.
[0262] The construction of the CODEC block 103 is the same as in
the case of FIG. 14.
[0263] In the ATM cell switch block 105, a transmission line block
I/F unit 1201 controls the interface of signals which are
communicated between the line block 106 (refer to FIG. 11) and the
ATM cell switch block 105.
[0264] A CLAD block I/F unit 1204 controls the interface of signals
which are communicated between the ATM cell switch block 105 and
the CLAD block 104.
[0265] An ATM cell switch 1202 autonomously routes an ATM cell
received from the line block I/F unit 1201 or the CLAD block I/F
unit 1204 on the basis of the contents of a switching table unit
1203 which stores switching information therein, and a VPI/VCI
value which is affixed to the header part of the ATM cell.
[0266] Prior to the routing, a header analysis unit 1202a included
in the ATM cell switch 1202 analyzes the VPI/VCI value set in the
header part of the received ATM cell. On the basis of the result of
the analysis, a header alteration unit 1202b included in the ATM
cell switch 1202 rewrites the VPI/VCI value contained in the header
part, into a value corresponding to the block of the destination of
the ATM cell.
[0267] Here, in the ordinary state, a routing control unit 1205
sets the switching table of this ordinary state stored in a set
information storage unit 1206, in the switching table unit 1203.
Then, the header alteration unit 1202b performs a routing control
as explained below, on the basis of the set contents of the
switching table unit 1203.
[0268] By way of example, in the construction shown in FIG. 11,
when the header analysis unit 1202a has judged that the header part
of the ATM cell received at the port A (line block I/F unit 1201)
bears the VPI/VCI value corresponding to the transmission address
(11) of the line block 106(#1), the header alteration unit 1202b
rewrites the VPI/VCI value of the header part of the ATM cell, into
a value corresponding to the reception address (1) of the CLAD
block 104(#1) connected to the port B, and it thereafter transfers
the resulting ATM cell into the ATM cell switch 1202. As a result,
the ATM cell switch 1202 autonomously routes the above ATM cell so
as to be transferred to the port B (CLAD block I/F unit 1204), on
the basis of the port number information of the port A and the
VPI/VCI value affixed to the header part of the ATM cell.
[0269] Besides, when the header analysis unit 1202a has judged that
the header part of the ATM cell received at the port C (line block
I/F unit 1201) bears the VPI/VCI value corresponding to the
transmission address (13) of the line block 106(#2), the header
alteration unit 1202b rewrites the VPI/VCI value of the header part
of the ATM cell, into a value corresponding to the reception
address (3) of the CLAD block 104(#2) connected to the port B, and
it thereafter transfers the resulting ATM cell into the ATM cell
switch 1202. As a result, the ATM cell switch 1202 autonomously
routes the above ATM cell so as to be transferred to the port B, on
the basis of the port number information of the port C and the
VPI/VCI value affixed to the header part of the ATM cell.
[0270] Also, when the header analysis unit 1202a has judged that
the header part of the ATM cell received at the port B bears the
VPI/VCI value corresponding to the transmission address (2) of the
CLAD block 104(#1), the header alteration unit 1202b rewrites the
VPI/VCI value of the header part of the ATM cell, into a value
corresponding to the reception address (12) of the line block
106(#1) connected to the port A, and it thereafter transfers the
resulting ATM cell into the ATM cell switch 1202. As a result, the
ATM cell switch 1202 autonomously routes the above ATM cell so as
to be transferred to the port A, on the basis of the port number
information of the port B and the VPI/VCI value affixed to the
header part of the ATM cell.
[0271] Further, when the header analysis unit 1202a has judged that
the header part of the ATM cell received at the port B bears the
VPI/VCI value corresponding to the transmission address (4) of the
CLAD block 104(#2), the header alteration unit 1202b rewrites the
VPI/VCI value of the header part of the ATM cell, into a value
corresponding to the reception address (14) of the line block
106(#2) connected to the port C, and it thereafter transfers the
resulting ATM cell into the ATM cell switch 1202. As a result, the
ATM cell switch 1202 autonomously routes the above ATM cell so as
to be transferred to the port C, on the basis of the port number
information of the port B and the VPI/VCI value affixed to the
header part of the ATM cell.
[0272] On the other hand, when the relaying state has occurred, the
routing control unit 1205 sets in the switching table unit 1203 the
switching table of this relaying state correspondent to the
particular-CLAD peculiar number value concerning the CLAD block 104
as is notified as particular-voice-channel identification data
(opposing-channel address information notification) by a
particular-voice-channel identification data detection unit 1006
included in the CLAD block 104. Then, the header alteration unit
1202b performs a routing control as explained below, on the basis
of the set contents of the switching table unit 1203.
[0273] By way of example, in the construction shown in FIG. 12,
when the header analysis unit 1202a has judged that the header part
of the ATM cell received at the port A (line block I/F unit 1201)
bears the VPI/VCI value corresponding to the transmission address
(11) of the line block 106(#1), the header alteration unit 1202b
rewrites the VPI/VCI value of the header part of the ATM cell, into
a value corresponding to the reception address (14) of the line
block 106(#1) connected to the port C, and it thereafter transfers
the resulting ATM cell into the ATM cell switch 1202. As a result,
the ATM cell switch 1202 autonomously routes the above ATM cell so
as to be transferred to the port C (line block I/F unit 1201), on
the basis of the port number information of the port A and the
VPI/VCI value affixed to the header part of the ATM cell.
[0274] Besides, when the header analysis unit 1202a has judged that
the header part of the ATM cell received at the port C (line block
I/F unit 1201) bears the VPI/VCI value corresponding to the
transmission address (13) of the line block 106(#2), the header
alteration unit 1202b rewrites the VPI/VCI value of the header part
of the ATM cell, into a value corresponding to the reception
address (12) of the line block 106(#1) connected to the port A, and
it thereafter transfers the resulting ATM cell into the ATM cell
switch 1202. As a result, the ATM cell switch 1202 autonomously
routes the above ATM cell so as to be transferred to the port A, on
the basis of the port number information of the port C and the
VPI/VCI value affixed to the header part of the ATM cell.
[0275] In this way, the ATM cell switch block 105 alters the
switching paths so that the pertinent ATM cells may be directly
switched between the line blocks 106(#1) and 106(#2). Thus, the
foregoing functions of the third preferred embodiment of the
present invention are realized.
Fourth Practicable System Architecture Corresponding to the Third
Preferred Embodiment of the Present Invention
[0276] FIG. 17 is a block diagram showing the fourth practicable
system architecture which concerns the ATM cell switch block 105
and the CLAD block 104 corresponding to the foregoing third
preferred embodiment of the present invention illustrated in FIGS.
11 and 12.
[0277] The construction of the ATM cell switch block 105 is the
same as in the case of the third practicable system architecture
shown in FIG. 16. Also, the construction of the CLAD block 104 is
almost the same as in the case of the third practicable system
architecture shown in FIG. 16. However, when the particular-CLAD
peculiar number value is to be outputted as the
particular-voice-channel identification data from the MUX unit
1004, it is put into an HDLC (High-level Data Link Control) frame
by an HDLC framing unit 1301. In correspondence with the framing
operation, an HDLC analysis unit 1302 is arranged on this side of
the particular-voice-channel identification data detection unit
1006. The HDLC analysis unit 1302 derives data in which the
particular-voice-channe- l identification data can be contained,
from a received HDLC frame, and it delivers the derived data to the
particular-voice-channel identification data detection unit
1006.
[0278] Owing to such a construction, the communications of control
data of higher precision are realized. Moreover, the
passing-particular-equipment identification data can be framed in
accordance with the HDLC. In this case, the relaying of ATM cells
can be actualized by an ATM equipment having no CODEC blocks 103 or
by the CLAD device only.
* * * * *