JPH06350636A - Distribution connection control system for atm network - Google Patents

Abstract

PURPOSE:To attain connection control at a high speed by defining a logic communication channel and a signal control channel among all terminal equipments and providing a state management means making connection control among the terminal equipments to each terminal equipment. CONSTITUTION:Lots of logic channels are set to a subscriber line 2 in the ATM communication system and a logic communication channel for real communication is defined in advance among all terminal equipments 1. Moreover, a signal control channel is similarly defined in advance among all the terminal equipments 1. Then only state management means 10 between outgoing and incoming terminal equipments 1 make control between the terminal equipments 1. A communication control section 3A in an exchange 3 makes setting/ maintenance management of the logic communication channel and the communication control channel and is not participated in connection control. That is, only the state management means 10 between outgoing and incoming terminal equipments 1 make control between the terminal equipments 1. Thus, high speed connection control is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed control system for an ATM network. In private premises of companies, universities, etc., it is common to install a private branch exchange (PBX) and connect terminals such as a telephone and a personal computer to this to build a private branch exchange network. In addition, recently, in response to the multi-media of terminals and services, studies for multi-media of networks have been actively conducted, and the practical application research of the ATM communication system has been advanced as a system for realizing this. .

The ATM communication system is a 5-byte header and 48 bytes on a 150 Mbps subscriber line interface.
Terminal data is transferred in fixed length packets called ATM cells made up of byte data, and the channel on the subscriber line is identified by VPI / VCI written in the header field. Therefore, a large number of logical channels (which can be represented by VPI / VCI) can be set on the subscriber line, and the terminal can communicate with the partner terminal via this logical channel.

[0003]

2. Description of the Related Art FIG. 9 is a block diagram showing a configuration example of a conventional system. In the system shown in the figure, a plurality of terminals 1 are connected to an exchange 3 via a subscriber line 2. In this system, the terminal 1 sends dial information or the like to the exchange 3 prior to the actual communication (), and the exchange 3 selects / calls the partner terminal 1 according to this information (). Next, the communication control unit 3A in the exchange 3 controls the switch 3B (), establishes a path, and sets a communication channel ().

[0004]

In the above-mentioned conventional system, the communication channel setting is centrally managed by the communication control unit 3A. For this reason, in an exchange that accommodates a large number of terminals 1, if the number of communication requests from the terminals 1 increases, the processing required for connection increases, and therefore some delay in connection cannot be avoided.

In the case of a normal telephone connection, in order to suppress this connection delay to a maximum of about 2 seconds even during the busy hour, the communication control unit 3A shown in FIG.
We are trying to improve processing capacity. However, in a multimedia communication environment handling inter-computer communication and the like, the demand for connection delay is more stringent and less than 1 second (several hundred ms).
A switched connection in c) is expected.

On the other hand, in the case of ATM communication capable of realizing a multimedia communication environment, since many logical channels can be set on the subscriber line 2, complicated control such as channel management and band management is further performed. It will be necessary, and the processing related to the connection will be further increased. Therefore, in order to satisfy the above requirements, it is difficult to realize high-speed connection control in the connection control according to the conventional method, because the communication control unit 3A becomes more complicated and the software implementation scale becomes enormous. .

The present invention has been made in view of the above problems, and enables high-speed connection control.
The purpose is to provide a distributed connection control system for a TM network.

[0008]

FIG. 1 is a block diagram showing the principle of the present invention. The same parts as those in FIG. 9 are designated by the same reference numerals. The system shown in the figure constitutes an ATM switching network in which a plurality of terminals 1 are connected to a switching system 3 via subscriber lines 2, respectively. In the switch 3B in the exchange 3, a logical communication channel (P
VC) and a signal control channel (S-PV) for signal control.
C) is defined. The solid line in the figure is PVC (real communication channel), and the broken line is S-PVC (signal control channel).
Reference numeral 10 is a state management means provided in each terminal 1 for managing the state of the network.

[0009]

In the ATM communication system, a large number of logical channels (the number of which can be represented by 8 bits of VPI and 16 bits of VCI) can be set on the subscriber line 2. Utilizing this feature, as shown in FIG. 1, a logical communication channel (PVC) for actual communication is defined in advance between all terminals 1.
Similarly, for the signal control channel, a signal control channel (S-PVC) is defined between all terminals 1.

Then, the connection control between the terminals 1 is performed only by the state management means 10 between the calling and receiving terminals 1. The communication control unit 3A in the exchange 3 uses these PVC and SP.
Performs only VC setting / maintenance and does not participate in connection control. That is, the connection control between terminals is performed only by the state management means 10 between the originating and receiving terminals 1. As a result,
High-speed connection control can be performed.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. In the principle diagram shown in FIG. 1, the case where four terminals 1 are connected to the exchange 3 is shown, but in an actual embodiment, a larger number of terminals 1 are connected to the exchange 3.
The state management means 10 in each terminal 1 has the following functions. It manages the communication status of its own terminal. A communication request is sent to the partner terminal via the S-PVC. The communication request from the partner terminal is monitored via the S-PVC. Since the state management means 10 has the above-mentioned functions, connection control between terminals can be performed only by the state management means 10 between the originating and receiving terminals 1.

FIG. 2 is a block diagram showing the essential parts of an embodiment of the present invention. In the illustrated embodiment, the subscriber line 2
The case where three PVC and three S-PVC logical channels are set is shown above. In terminal 1, 11,
Reference numeral 12 is a cell transmission / reception circuit that controls transmission / reception of cells transmitted through the PVC. Two cell transmitting / receiving circuits are provided for the purpose of performing data transfer with a plurality of PVCs at the same time. A third cell transmission / reception circuit 13 performs signal control of a cell for a control signal via S-PVC.

Reference numerals 14 and 15 denote cell transmission / reception circuits 1 respectively.
A communication circuit connected to 1 and 12 is a user-dependent upper function such as analog / digital mutual conversion processing in the case of a voice signal and control of an open window such as a multi-window. A state management unit 16 manages the communication state. This state management unit 16 is
A used / unused display area 16b for the C value 16a,
A region 16c in which a total Mbps of used bands is managed is configured. A user request analysis unit 17 analyzes a user request, and is composed of a dial number 17a and a PVC value 17b corresponding thereto.

Reference numeral 18 denotes a signal processing section connected to the third cell transmission / reception circuit 13 for transmitting control signals such as call setting information and call disconnection request, and for receiving the control signals transmitted. Reference numeral 20 is a pass cell counter unit that counts the number of cells passing through the cell transmission / reception circuits 11 and 12, and reference numeral 21 is a band operation unit that receives an output from the pass cell counter unit 20 and calculates a used band. The band calculation unit 21 is connected to the state management unit 16. Passing cell counter unit 20
Is for counting the total number of cells flowing on the transmission line per unit time, and the band calculation unit 21 calculates the used band on the transmission line based on the number of passing cells. The passing cell counter section 20 and the band operation section 21 constitute a monitoring means 30 for monitoring the cell flow rate flowing on the subscriber line. Reference numeral 31 is a connection allowable time management unit that is connected to the user request analysis unit 17 and manages the allowable time for performing the connection retry operation. The constituent elements described above constitute the state management means 10 shown in FIG. The operation of the apparatus configured as described above will be described using a flowchart.

FIG. 3 is a flow chart showing an operation example of the present invention when a communication request occurs. User request unit 17
When the communication request from the user occurs, the required bandwidth Ba
The PVC to be used is analyzed (S1). The analysis result is sent to the state management unit 16.

The status management unit 16 determines the status of the PVC to be used (S2). Specifically, it is determined whether the requested PVC is in use by referring to the state of 16b. If the PVC is in use, the terminal 1 restricts outgoing calls (S3). When the PVC is unused, the state management unit 16 refers to the used bandwidth total area 16c to determine the free bandwidth on the own subscriber line (S4). In this case,
The passing cell counter unit 20 counts the number of passing cells of the cell transmitting / receiving circuit 11. The band calculation unit 21 is notified of the count result. The band calculator 21 calculates the band used on the subscriber line 2 based on the number of passing cells. The state management unit 16 receives the output of the band calculation unit 21 and corrects the empty band according to the actual usage condition. In the case of the free bandwidth determination based on the user-reported value, if the accuracy of the reported value from the user is lost, there is a risk that the communication quality may be adversely affected. Can be reduced.

If the corrected free band is smaller than the required band Ba, it is impossible to communicate, and therefore transmission is restricted (S3). If the available bandwidth is larger than the required bandwidth Ba, the status information of the own terminal is updated (S
5). Specifically, the corresponding part of the area 16b is set to be in use, Ba is added to the total used bandwidth of the area 16c, and a new free area is set to (free area-Ba).

Next, the signal processor 18 sends the corresponding SP signal.
A SETUP request is transmitted to the VC (S6). This SET
The UP signal includes the PVC value and the used band Ba. Next, the signal processing unit 18 waits for a response from the partner terminal (S7). Disconnect from the other terminal 1 (DISCO
Upon receipt of (NECT), the user request analysis unit 17 notifies the user that connection is impossible (S8).

The signal processing unit 18 is connected (CONNECT)
Upon receiving T), the communication circuit 14 (15) and the cell transmission / reception circuit 11 (12) start communication via the PVC (S9). Next, the user request analysis unit 17 and the signal processing unit 18 wait for a disconnection request (S10). Here, when the user request analysis unit detects a disconnection request from the user of the own terminal, the signal processing unit 18 transmits DISCONNECT to the corresponding S-PVC (S11), and then the state management unit 16 , Updates the status information of its own terminal (S1
2).

On the other hand, DISCONNEC from the other terminal
When T is received, the state management unit 16 updates the state information of its own terminal (S12). That is, in (S12),
The PVC of the corresponding area 16b is returned to unused, Ba is subtracted from the used bandwidth of the area 16c to return to the original used bandwidth, and
A new empty area is obtained by adding Ba to the existing empty area.

FIG. 4 is a flow chart showing another operation example of the present invention when a communication request occurs. In this flowchart, the steps up to step S6 are the same as those in the embodiment of FIG. In this example, SET to the corresponding S-PVC.
After transmitting the UP request, the connection permissible time management unit 31 starts the monitoring timer (S7). Then, the process waits for a response from the partner terminal (S8).

When DISCONNECT is received from the partner terminal, it is checked whether the monitoring timer at that time is less than the allowable time (S9). If the time is less than the allowable time, the process returns to step S6, and the S-PVC corresponding to the S is again returned to S.
Send ETUP. With such a mechanism, the connection process is retried within the range of the user request, so that the connection may be possible, and the connection efficiency can be improved.

If the monitoring timer is not the permissible time in step S9, the user is notified that connection is impossible (S1).
0). When the CONNECT is received from the partner terminal in step S8, the same sequence as the embodiment shown in FIG. 3 is taken. That is, the signal processing unit 18 is connected (CONNECT).
When CT) is received, the communication circuit 14 (15) and the cell transmission / reception circuit 11 (12) start communication via the PVC (S11). Next, the user request analysis unit 17 and the signal processing unit 18 wait for a disconnection request (S12). Here, when the user request analysis unit detects a disconnection request from the user of the own terminal, the signal processing unit 18 corresponds to the SP.
DISCONNECT is transmitted to the VC (S13), and then the state management unit 16 updates the state information of its own terminal (S14).

On the other hand, DISCONNECT from the other terminal
When T is received, the state management unit 16 updates the state information of its own terminal (S14). That is, in (S14),
The PVC of the corresponding area 16b is returned to unused, Ba is subtracted from the used bandwidth of the area 16c to return to the original used bandwidth, and
A new empty area is obtained by adding Ba to each empty area.

FIG. 5 is a flow chart showing an operation example of the present invention when a communication request is received. Signal processing unit 18
When the communication request (SETUP) from the S-PVC is received via the cell transmission / reception circuit 13, the requested bandwidth Ba and PV
The C number is analyzed (S1). The analysis result is notified from the signal processing unit 18 to the user request analysis unit 17.

The user request analysis unit 17 uses S in the area 17b.
-Check the sender address from the PVC number (S2).
Next, the state management unit 16 determines the free band on the own subscriber line based on the information provided by the user request analysis unit 17 (S3). At this time, the band calculation unit 21 calculates the band from the number of communication cells counted by the communication cell counter unit 20, and corrects the empty band from the area 16c managed by the state management unit 16 according to the actual usage.

When the corrected free band is smaller than the required band Ba, the signal processing unit 18 causes the cell transmission / reception circuit 13 to operate.
A DISCONNECT response is transmitted to the corresponding S-PVC via (S4). When the free area is larger than the requested bandwidth Ba in step S3, the user request analysis unit 17
Whether or not the user can respond is determined by referring to the areas 17a and 17b (S5). When the user response is not possible, the signal processing unit 18 transmits a DISCONNECT response to the corresponding S-PVC.

When the user can respond, the status management unit 1
6 updates the status information of its own terminal (S6). That is, the state of the area 16b is set to be in use, Ba is added to the total used bandwidth of the area 16c, and Ba is subtracted from the free area to obtain a new free area. Next, the signal processing unit 18
CONN to the corresponding S-PVC via the cell transmission / reception circuit 13.
The ECT response is transmitted (S7).

The signal processing unit 18 is connected (CONNECT)
When T) is transmitted, the communication circuit 14 (15) and the cell transmission / reception circuit 11 (12) start communication via the PVC (S8). Next, the user request analysis unit 17 and the signal processing unit 18 wait for a disconnection request (S9). Here, when the user request analysis unit detects a disconnection request from the user of the own terminal, the signal processing unit 18 adds D to the corresponding S-PVC.
The ISCONNECT is transmitted (S10), and then the state management unit 16 updates the state information of its own terminal (S1).
1).

On the other hand, DISCONNECT from the other terminal
When T is received, the state management unit 16 updates the state information of its own terminal (S11). In other words (in S11),
The PVC of the corresponding area 16b is returned to unused, Ba is subtracted from the used bandwidth of the area 16c to return to the original used bandwidth, and
A new free area is obtained by adding Ba to the free area up to that point.

FIG. 6 is a block diagram showing the configuration of another embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals. This embodiment shows an example in which two exchanges 3 are connected between terminals 1. A relay transmission line 4 is provided between the exchanges 3.
Connected with 0. Reference numeral 3C is a transmission line corresponding unit provided in each exchange 3.

In the system thus constructed, the operation of each terminal 1 is the same as that of the system shown in FIG. This is because the terminal 1 has PVC, S preset by the exchange 3
This is because it is only necessary to be conscious of the PVC and it is not necessary to be conscious of the network form. In this case, if the relay transmission line 40 has no free band, End-to-
The connection control is completed between the terminal 1 and the transmission path corresponding unit 3C, not between the End terminals. On the other hand, when the relay transmission line 40 has a free band, the transmission line corresponding unit 3C only transfers the control message, and the connection control is End-to-E.
nd terminal. Even in these cases, the exchange 1 is not involved in connection control between terminals, as in the case of FIG.

FIG. 7 is a block diagram showing an example of a detailed configuration of the transmission line corresponding section 3C. In the figure, 50 is a cell receiving unit, one of which is connected to the switch 3B, and 51 is a cell receiving unit, one of which is connected to the relay transmission line 40 side. 52
One of the cell transmitters, one of which is connected to the switch 3B,
Reference numeral 3 is a cell transmission unit, one of which is connected to the relay transmission line 40.

Reference numeral 54 denotes a cell receiving section 51 and a cell transmitting section 53.
And a physical interface circuit connected to the relay transmission line 40. 55 is a cell receiving unit 50, 5
A request detecting unit for receiving various signals from the user 1 and detecting various requests from the user, and a signal processing unit 56 connected to the request detecting unit 55 and sending a control signal to the cell transmitting unit 52.

Reference numeral 57 denotes a cell receiving section 51 and a cell transmitting section 53.
A pass cell counter unit that is connected to the counter unit and counts the number of pass cells, and a band operation unit 58 that receives the output of the pass cell counter unit 57 and calculates the actual use band. The passing cell counter 57 and the band calculator 58 constitute a monitoring means 60 for monitoring the cell flow rate flowing on the transmission path. The output of the band calculator 58 is input to the request detector 55. The cell receivers 50 and 51 receive the actual data cells and the signal control cells, and the cell transmitters 52 and 53 transmit the actual data cells and the signal control cells. The pass cell counter 57 and the band calculator 55 in the transmission line corresponding unit 3C correspond to the pass cell counter 20 and the band calculator 21 of FIG.
The vacant band is corrected based on the actual number of passing cells on the transmission line.

FIG. 8 is a flowchart showing the operation of the transmission path corresponding unit 3C. Upon receiving the cell (S1), the cell receiving unit 50 or 51 determines the cell type (S2). If the cell is other than SETUP, the process returns to the cell reception sequence. When the cell is SETUP, the cell reception unit 50 or 51 transfers the SETUP request to the request detection unit 55 (S3).

The request detection unit 55 analyzes the PVC number of the cell and the requested bandwidth Ba (S4). Then, the free band on the transmission path is determined (S5). In this case, the passing cell counter unit 57 is connected to the cell receiving unit 51 and the cell transmitting unit 53, and counts the number of passing cells on the transmission path. The count result is notified to the band calculation unit 58. The band calculator 58 calculates the band used on the transmission path based on the number of passing cells. Request detector 55
Receives the output of the band calculation unit 58 and corrects the vacant band according to the actual usage condition.

When the free band on the transmission line corrected in accordance with the actual use condition is smaller than the required band Ba in this way, data transmission between the terminals 1 via this transmission line is impossible, so the signal processing unit 56 The DISCONNECT is returned to the cell transmission unit 52 or the cell transmission unit 53 (S6). The cell transmitting unit 52 or 53 that has received this DISCONNECT
Sends DISCONNECT to terminal 1 using a predetermined S-PVC.
Is returned (S7).

In step S5, if the free band on the transmission line is larger than the required band Ba, data transfer is possible, so the request detection unit 55 updates the state information of the transmission line (S8). That is, from the free bandwidth to the required bandwidth Ba
The value obtained by subtracting is used as a new free band. Next, the request detection unit 55 transfers the SETUP to the cell transmission unit 52 or 53 (S9). At this time, the required bandwidth Ba is put into SETUP.

The request detection unit 55 waits for a response from the adjacent exchange 3 (S11). At this time, when DISCONNECT is received from the adjacent exchange 3, the request detection unit 55 updates the status information of the transmission path. Request detector 5
When 5 receives CONNECT, it waits for a disconnection request (S12). Until the disconnection request arrives, the terminals are in communication with each other. During this time, if DISCONNECT is received from the own exchange or the adjacent exchange, it means that the communication between the terminals has ended, and therefore the request detection unit 55 updates the state information of the transmission path (S13).
That is, the bandwidth is released by setting the required bandwidth Ba added to the free area as a new free area.

[0041]

As described above in detail, according to the present invention, in an ATM switching system in which a large number of terminals are connected to an exchange, even when communication requests are concentrated in a certain time zone, the terminals are connected to each other. The connection control operation is performed for each terminal that has made a communication request, and the exchange does not need to be involved in this, so that connection delay due to a decrease in the throughput of the exchange does not occur. In addition, for terminals that require higher-speed connection control, the connection time can be shortened freely by improving the processing capacity of the terminal itself, which imposes restrictions on the design / production of the terminal and its applications. Absent.

As described above, according to the present invention, it is possible to provide a distributed connection control system for an ATM network capable of performing high-speed connection control, which has a great practical effect.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a configuration block diagram showing a main part of an embodiment of the present invention.

FIG. 3 is a flowchart showing an operation example of the present invention when a communication request occurs.

FIG. 4 is a flowchart showing another operation example of the present invention when a communication request is generated.

FIG. 5 is a flowchart showing an operation example of the present invention when a communication request is received.

FIG. 6 is a configuration block diagram showing another embodiment of the present invention.

FIG. 7 is a block diagram illustrating a detailed configuration example of a transmission path corresponding unit.

FIG. 8 is a flowchart showing an example of the operation of the transmission path corresponding unit.

FIG. 9 is a block diagram showing a configuration example of a conventional system.

[Explanation of symbols]

 1 Terminal 2 Subscriber Line 3 Switch 3A Communication Control Unit 10 State Management Means

Claims (6)

[Claims] 1. A subscriber line (2) to each of the exchanges (3)
In an ATM switching network in which a plurality of terminals (1) are connected via a network, a logical communication channel (PVC) for actual communication and a signal control channel (S for signal control) between all terminals (1).
-PVC) is defined, state management means (10) for managing the state of the network is provided in each terminal (1), and connection control between terminals (1) is performed between the originating and receiving terminals (1). A distributed connection control system for an ATM network, characterized in that it is performed only by the state management means (10). 2. The state management means (10) has a function of managing a communication state of the own terminal, a function of sending a communication request to a partner terminal via S-PVC, and a partner terminal via S-PVC. And a function of monitoring a communication request from the terminal (1) so that connection control between the terminals (1) is performed only by the state management means (10) between the calling and receiving terminals (1). 1. An ATM network distributed connection control system according to 1. 3. The state managing means (10) is provided with a monitoring means (30) for monitoring a cell flow rate flowing on a subscriber line, and when making a call request to another terminal (1) or when another terminal (1) is used. )
3. A distributed connection control system for an ATM network according to claim 2, wherein when an incoming call request is received from the ATM, outgoing call control and incoming call control are performed based on the monitoring result of the monitoring means (30). 4. The state management means (1) manages the maximum allowable connection time declared together with the connection request from the user, and after the calling terminal (1) sends out the SETUP request, D
The connection allowable time management unit (31) for monitoring the time until the ISCONNECT is received is provided, and the connection processing is retried when the first connection processing fails within the maximum connection allowable time. 3. A distributed connection control system for an ATM network according to claim 2. 5. An ATM switching network in which a plurality of terminals (1) are connected to a switching system (1) via subscriber lines, and at least two switching systems (3) are relay transmission lines (40). In a system connected via a switch, a transmission line corresponding unit (3C) that manages the communication state of the relay transmission line is provided in each exchange (3), and from the terminal (1) accommodated in the exchange (3), When there is a communication request, the communication request is transferred to the adjacent exchange (3) based on the management information of the transmission path corresponding unit (3C), whereby the connection between the exchanges is performed. Item 1. A distributed connection control system for an ATM network according to item 1. 6. A transmission unit (3C) is provided with a monitoring means (60) for monitoring the flow rate of cells flowing on the transmission line, and a communication request is issued from the terminal (1) accommodated in the exchange (3). The distributed connection control system for an ATM network according to claim 5, wherein if there is, the transmission control is performed based on the monitoring result of the monitoring means (60).