JPH0637777A - Network system - Google Patents

Abstract

PURPOSE:To provide a network system of the line exchange system able to reduce the effect onto the network on the occurrence of a fault. CONSTITUTION:An endoscope diagnostic device 13, an ultrasonic wave diagnostic device 14, a digital X-ray diagnostic device 15, an X-ray CT device 16, a nuclear magnetic resonance diagnostic device 17, and a nuclear medical diagnostic device 18 transfer picture data obtained from the picture diagnostic devices to a database 20 via a network 11 and the database 20 stores medical picture data. A line watchdog timer monitoring a line connection time is provided in the inside of an STN 12' connecting to the database 20 and work stations 19 in the network 11. The line watchdog timer is started when a setup reply is made to a setup request. Since an interrupt request is inputted externally normally (when no fault is in existence), the timer is released from the interrupt request. If a fault takes place in a transmission line interconnecting databases 20 and work stations 19, since no interrupt request reaches the STN12', the line watchdog timer in the STN12' expires and the line is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to data transmission in a circuit switching system, and more particularly to a circuit usage time management means in a network system that provides circuits.

[0002]

2. Description of the Related Art There are telephone (voice), video conference (video), etc. as network communication by a circuit switching system. Line usage time is particularly limited (limited) in these networks
It has not been.

FIG. 2 is a block diagram showing a system configuration example of data transmission in the conventional circuit switching system, and FIG.
Is a timing chart of the line connection control procedure.
The main components will be described. 21 is a network, 2
Reference numeral 2 is a network control device (hereinafter referred to as STN) for controlling the data link layer and below of the network, 23 is a telephone (PHONE), and 24 is a telephone line exchange (PBX) used in the premises.

The STN 22 controls a frame and a physical layer in a time division multiplexing network. STN22
May be independent as a terminal or may be implemented in the terminal. An STN having a function of performing line management for line use requests from a plurality of terminals is called SVS.

The line connection is started when the PBX 24 issues a line setting request to the network 21 by outputting a telephone number from the telephone set 23. Upon receiving the setting request command, the STN 22 sends a line connection request in the network 21 to the SVS managing the line in the network 21. The SVS returns an affirmative response if there is a free line and a negative response if the line is full. The voice communication between the telephones 23 becomes possible when the line is connected.

Similarly to the line connection, in the line disconnection, the PBX 24 disconnects the internal line by a disconnect signal from the telephone and issues a disconnection request to the network 21. STN22 is SV
A request to open the line in the network 21 is issued to S.

As described above, the line disconnection in the line switching system is a terminal (for example, a telephone, T
It is executed only by a trigger (disconnection) from V etc.). Also,
In a circuit-switched network, the usage time of the line cannot be limited, even from the usage form.

[0008]

When transferring a large amount of data such as a medical image in a circuit of a circuit switching system, it is necessary to increase the capacity per line. When the broadband line is used, for example, by transferring image data by using it as a network of a medical image communication system, the line using device is connected to the network when some trouble occurs and the line is not released. Another device had the inconvenience that the line could not be used.

In this case, the telephone has a small capacity of 64 Kbps per line and generally has a large number of lines, so that the influence on the network system is small. However, when used as a large-capacity line in an image communication system or the like, the number of lines cannot be set so that, for example, even if one line cannot be used, the influence on the network system becomes large (for example, there is a problem. 10,
(If the 0 Mbps line is a 3-channel network and one line is not released, the network capacity will be reduced to 2/3).

The present invention has been made in view of the above inconveniences and problems, and an object of the present invention is to provide a circuit switching type network system capable of reducing the influence on the network system when a failure occurs.

[0011]

To achieve the above object, a network system of the present invention comprises a communication system, a plurality of network control devices connected to the communication system, and a terminal device connected to the network control device. In the circuit system of the circuit switching system, the network control device comprises a relay means for relaying transmission data exchange between the communication system and the terminal device, and a line monitoring means for monitoring the line usage time of the terminal device. When the line monitoring means detects that the connection time between the network control device and the terminal device exceeds a predetermined line use time, the line connected to the terminal device is released. In the above network system, the terminal device sends a line usage request to the network control device together with a line usage request made before the line acquisition, and the network control device sends a value larger than the line usage scheduled time to the line of the terminal device. The usage time may be set in the line monitoring means, or the terminal device sends a parameter value indicating the transfer data amount to the network control device together with the line usage request made before the line acquisition, and the network control device sends the parameter value. The line use scheduled time may be calculated based on the calculated line use time and set in the line monitoring means as the line use time of the terminal device. Further, in the above network system, the line monitoring means monitors whether or not the terminal device is in communication, and when the non-communication time exceeds a predetermined line use time, the network control device connected to the terminal device. Can also be configured to release the line connected to the terminal device.

Another network system of the present invention is a communication system, a plurality of relay devices connected to the communication system, a terminal device connected to the relay device, and lines from the plurality of terminal devices via the relay device. In a circuit switching type network system including a network management device for managing a line for a use request, a relay means relays transmission data exchange between a communication system and the terminal device, and the network management device controls each terminal. When the line monitoring means detects that the connection time with the corresponding relay device among the respective terminal devices exceeds the predetermined line usage time, the terminal device has a line monitoring means for monitoring the line usage time of the equipment. A network system characterized by releasing the line connected to. In the above network system,
The terminal device sends the line usage request to the network management device together with the line usage request made before the line is acquired, and the network management device sets a value larger than the line usage scheduled time in the line monitoring means as the line usage time of the terminal device. Alternatively, the terminal device sends a parameter value indicating the transfer data amount to the network management device together with the line usage request made before the line is acquired, and the network management device calculates the expected line usage time based on the parameter value. Then, the line monitoring time may be set as the line use time of the terminal device. Further, in the other network system, the line monitoring means monitors whether or not the terminal device is in communication, and when the non-communication time exceeds a predetermined line use time, the network management device causes the terminal device to communicate. It is also possible to make a summary that releases the line connecting with.

[0013]

In the network system of the present invention having the above structure, the network control device relays the transmission data exchange between the communication system and the terminal device by the relay device, and the monitoring device monitors the line use time of the terminal device. When the connection time between the control device and the terminal device exceeds a predetermined line use time, the line connected to the terminal device is released.

In another network system of the present invention, the relay means relays transmission data exchange between the communication system and the terminal device, and the network management device uses the line monitoring means to monitor the line use time of each terminal device. Monitor
Among the respective terminal devices, the line connected to the terminal device whose connection time with the corresponding relay device exceeds the predetermined line use time is released.

In each of the above network systems, the line monitoring means monitors whether or not the terminal device is in communication, and when the non-communication time exceeds a predetermined line use time, You can also release the connection line.

[0016]

1 is a block diagram showing the configuration of a medical image data communication system as an embodiment of a data transmission system in a circuit switching system according to the present invention. FIG. 4 is a timing chart of the line connection control procedure. The main components will be described. 11 is a network, 12
Reference numeral 12 'is a network control device (hereinafter, referred to as STN) for controlling the data link layer and below of the network, 13 to
Reference numeral 20 is an example of each terminal device used in the medical image data communication system connected to the network 11, 13 is an electronic endoscope diagnostic apparatus (ES), and 14 is an ultrasonic diagnostic apparatus (U).
S), 15 is a digital X-ray diagnostic apparatus (DR), 16 is X
X-ray CT apparatus (CT), 17 is a nuclear magnetic resonance diagnostic apparatus (M
R), 18 are nuclear medicine diagnostic devices (NM), 19 is a workstation (WS) as a medical image display device, and 20 is a medical image database (DB). In addition, STN1
In the time division multiplexing network, 2 and 12 'perform frame control and physical layer control. The STNs 12 and 12 ′ may be independent as terminals or may be mounted in the terminals. Further, the STN having a function of performing line management in response to line use requests from a plurality of terminals is called network management means (hereinafter referred to as SVS). Each STN connected to the database 20 and the workstation 19
Reference numeral 12 'internally has a line monitoring timer for monitoring the line connection time (to be described later; see FIGS. 11 and 12).

Endoscopic diagnostic device 13 and ultrasonic diagnostic device 1
4, the digital X-ray diagnostic apparatus 15, the X-ray CT apparatus 16, the nuclear magnetic resonance diagnostic apparatus 17, and the nuclear medicine diagnostic apparatus 18 transfer the image data obtained as the image diagnostic apparatus to the database 20 via the network 11. Then, the database 20 stores the medical image data transferred from the image diagnostic apparatus, and performs image retrieval and image reading in response to a request from the workstation 19. The workstation 19 sends a transfer request of an image for interpretation by the doctor to the database 20, displays the image transferred from the database 20 on the CRT, and the doctor interprets the image (one or more). .

FIG. 4 is a timing chart showing a normal sequence of the line connection control procedure of the medical image data communication system shown in FIG. In FIG. 4, the line control procedure is the same as in the conventional case.
A line setting request is input from the database 20, workstation 19)) and a setting response is output. The difference from the prior art is that the STN 12 ′ connected to the database 20 and the workstation 19 has a line monitoring timer for internally monitoring the line connection time. The line monitoring timer is set in response to a line setting request. Fires when a response is issued. Normally (when there is no failure), a disconnection request is input from the outside, so the timer is released by this disconnection request. If database 20 and workstation 19
Etc. or when a failure occurs in the transmission path connecting them to STN 12 '(Fig. 5), the disconnect request does not reach STN 12'. In this case, the line monitoring timer in STN 12 'times out and STN 12' Automatically issues a circuit open request to SVS. In the above description, the line monitoring timer is in the STN 12 ', but the present invention is not limited to this, and the line monitoring timer may be provided in the SVS (network management measure) to achieve the object of the present invention. The normal sequence in this case is shown in FIG. 6, and the sequence at the time of failure is shown in FIG.

FIG. 8 shows an STN (network control device) 1
2'is a hardware configuration example, a LOOP control unit 81 connected to the network 11, and an STN basic unit 82 including a CPU and a memory connected to the LOOP control unit 81.
And interfaces 83 to 85 as relaying means for connecting to the databases 20-1 to 20-3. The databases 20-1 to 20-3 exchange data with the network 11 via the interfaces 83 to 85, and the STN basic unit 82 controls it.

FIG. 9 shows an example of a frame structure of a trunk line (STN-STN), a frame control header (FH) 91 of 10 Mbit / s, a line connection control command area (CONT) 92 of 90 Mbit / s, and 100 Mbit each.
A 400 Mbit / s trunk line frame 90 composed of image data transfer areas (I-TS) 93 to 94 of / s is shown. Further, FIG. 10 shows a branch network (for example,
2M shows an example of frame structure of database STN)
bit / s frame control headers (FH) 101, 8
Mbit / s line connection control command area (CON
T) 102, a 100 Mbit / s image data transfer area (I-TS) 103, and a 110 Mbit / s branch line frame 100 are shown.

In this embodiment, the line monitoring timer is configured as a program means, and the PRO of the STN basic unit 82 is used.
It is stored in M (not shown) and is executed and activated by the CPU of the STN basic unit 82 when a setting response to the above-mentioned external line setting request is issued. Below, STN
The processing procedure of 12 'when normal and the processing procedure of failure will be described. 1. Processing procedure when the network controller is normal

FIG. 11 is a flow chart showing an example of the processing procedure of the STN 12 'under normal conditions. The processing procedure of the STN 12 'under normal conditions will be described below with reference to FIGS. [Step 111] Line Setting Request Command Reception The STN basic unit 82 receives the line setting request command transmitted from the database 20-1 via the interface 83. [Step 112] Transmission of Line Connection Request Command The STN basic unit 82 transmits the line connection request command to the SVS immediately after receiving the line setting request command. [Step 113] Reception of line connection response command

Upon receiving the line connection request command from the STN 12 ', the SVS determines whether the line connection is possible and sends the result as a line connection response command to the STN 12', and the STN basic unit 82 receives the line connection response command. To do. [Step 114] Timer set

Upon receipt of the line connection response command from the SVS, the STN basic unit 82 sets the line monitoring timer (starts the line monitoring timer by executing the line monitoring program). [Step 115] Set Mapping The STN basic unit 82 sets the mapping of the time slot between the interface 83 and the trunk line. [Step 116] Transmission of line setting response command The STN basic unit 82 sends a line setting command to the database 20-1 via the interface 83. [Step 117] Data relay

When the database 20-1 receives the line setting command, it starts transmission of the requested image data, but the image data is the interface 83 of the STN 12 '.
Via the network 11 to the network 11. Therefore, ST
N12 'functions as a relay point for data. [Step 118] Reception of line disconnection request command

When the transmission of the image data is completed, the database 20-1 sends a line disconnection request command to the STN basic unit 82 via the interface 83. ST
The N basic unit 82 receives the line disconnection request command [step 119] Transmission of line disconnection request command The STN basic unit 82 immediately transmits the line disconnection request command to the SVS. [Step 120] Reception of line release response command

Upon receiving the line release request command from the STN 12 ', the SVS sends the line release response command to the STN.
12 ', and the STN basic unit 82 receives the line release response command. [Step 121] Reset the timer

The STN basic unit 82 resets the line monitoring timer immediately after receiving the line open response command from the SVS (reset of the line monitoring timer by the line monitoring program). [Step 122] Cancellation of mapping The STN basic unit 82 cancels mapping of the time slot between the interface 83 and the trunk line. [Step 123] Transmission of Line Setting Response Command The STN basic unit 82 sends a line setting command to the database 20-1 via the interface 83. 2. Procedures for network controller failure

FIG. 12 is a flow chart showing an example of the processing procedure of the STN 12 'at the time of failure. The processing procedure of the STN 12 'at the time of failure will be described below with reference to FIGS. [Steps 111 to 117] Line setting request command reception-data relay Line setting request command reception-data relay procedure is the same as in the case of STN in the above-described normal state, and therefore description thereof is omitted. [Step 125] Occurrence of failure Due to some reason, the database 20-1 and STN1
Failure occurred on the 2'transmission line. [Step 126] Timeout

When a failure occurs, data is not transmitted from the terminal (for example, the database 20-1) to the STN as a relay point. Therefore, the line disconnection request command is not transmitted. When the line disconnection request command from the terminal is not received within the set time of the monitoring timer, the STN basic unit 82 considers that a failure has occurred and causes the monitoring timer to time out. [Step 127] Transmission of line release request command After the timeout occurs, the STN basic unit 82 immediately starts the SVS.
The line release request command is sent to. [Step 128] Reception of line release response command

When the SVS receives the line release request command from the STN 12 ', it sends a line release response command to the STN1.
2 ', and the STN basic unit 82 receives the line release response command. [Step 129] Transmission of line setting response command The STN basic unit transmits the line setting command to the database 20-1 via the interface 83.

Next, the time setting of the time monitored by the line monitoring timer will be described. This set time must be longer than the total of the image communication time for transferring from the database 20 to the workstation 19 and the software overhead time associated therewith (hereinafter referred to as the total transfer time). Also, in normal data transfer, the terminal device side has a retransmission function for errors in the transmission path. Therefore, the following equation can be set.・ Timer setting time = total transfer time x maximum number of retransmissions + α

For example, in a medical X-ray image, the amount of data per image is 2048 × 2048 × 16 bits, and the transmission path is 10
0 Mbit / s, software overhead is 0.1
If the maximum number of retransmits per second is 3, ・ Timer setting time = ((2048 × 2048 × 16/100 × 106 + 0.1) ×
It can be calculated as 3 = 2.3 + α. In this case, 3 seconds is set as the timer value. Further, if the accuracy of the timer itself is not good or the processing time of each component varies, it is necessary to further increase the time. Even in that case, the timer setting value does not affect the performance of the network system because it is activated only when a failure occurs. If the data transfer between the database 20 and the workstation 19 is a single image transfer, it may be set to a constant value in the system as described above. On the other hand, if the number of images captured in one inspection is large (even if it varies depending on the diagnostic device) and the number of images is 10 or more, the timer set value is set according to the maximum transfer amount, or By notifying the network of the data amount, the number of images, etc. for each line setting, it is possible to appropriately monitor the line use time. Specifically, the network can be notified of the above data amount and the number of images as parameters in the line setting command of the line connection sequence.

When the request from the terminal is communicated as a command parameter as described above, software overhead time is required. As a way to avoid this, the hardware monitors whether the image is transferred on the line that transfers the image, resets the timer if the image is transferred, and if the image is not transferred for a certain period of time, a timeout occurs. It may occur, and the case may be regarded as a failure occurrence. In this case, when the image data is transferred from the database to the line, a special code indicating that it is image data is added to the beginning of the line, the line is monitored by the STN, and the timer is reset when the special code is found. . By doing so, even if the application (usage form) of the network system changes and the image data to be transferred changes, it is possible to cope with the change without changing the STN or the like. Although one embodiment of the present invention has been described above, it is needless to say that the present invention is not limited to the above embodiment and various modifications can be made.

[0035]

As described above, according to the present invention, the time when the terminal connected to the network uses the line is monitored, and when the usage time exceeds a certain level, the line is connected to the terminal side. Since the function to open is added, the system performance does not deteriorate even if a failure occurs while keeping the broadband line.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a data transmission system in a circuit switching system according to the present invention.

FIG. 2 is a block diagram showing a system configuration example of data transmission in a conventional circuit switching system.

FIG. 3 is a timing chart of a line connection control procedure in the system configuration example of FIG.

FIG. 4 is a timing chart showing a normal sequence of the line connection control procedure of the present invention.

FIG. 5 is a timing chart showing a sequence at the time of a failure of the line connection control procedure of the present invention.

FIG. 6 is a timing chart showing a normal sequence of the line connection control procedure when the line monitoring timer is provided in the line management network control device.

FIG. 7 is a timing chart showing a sequence at the time of failure of the line connection control procedure when the line monitoring timer is provided in the line management network control device.

FIG. 8 is a hardware configuration example of a network control device.

FIG. 9 is an example of a frame configuration of a trunk line.

FIG. 10 is an example of a frame configuration of a branch line network.

FIG. 11 is a flowchart showing an example of a processing procedure of the network control device at the normal time.

FIG. 12 is a flowchart showing an example of a processing procedure of the network control device at the time of a failure.

[Explanation of symbols]

 11 network 12, 12 'network control device 19 workstation (terminal device) 20 database (terminal device) 82 STN basic unit 83-85 interface (relay means)

Claims (8)

[Claims] 1. A circuit switching network system comprising a communication system, a plurality of network control devices connected to the communication system, and a terminal device connected to the network control device, wherein the network control device comprises: It has a relay means for relaying transmission data exchange between the communication system and the terminal device, and a line monitoring means for monitoring the line usage time of the terminal device, the line monitoring means comprising the network control device and the terminal. A network system which releases a line connected to the terminal device when it is detected that the connection time with the device exceeds a predetermined line use time. 2. The network system according to claim 1, wherein the terminal device sends a line use request together with a line use request made before the line is acquired to the network control device,
A network system, wherein the network control device sets a value larger than the scheduled line use time to the line monitoring means as the line use time of the terminal device. 3. The network system according to claim 1, wherein the terminal device sends a parameter value indicating a transfer data amount to the network control device together with a line use request made before the line acquisition, and the network control device based on the parameter value. A network system characterized in that the line use scheduled time is calculated and is set in the line monitoring means as the line use time of the terminal device. 4. The network system according to claim 1, wherein the line monitoring means monitors whether or not the terminal device is in communication, and when the non-communication time exceeds a predetermined line usage time, A network system in which a network control device connected to a terminal device releases a line connected to the terminal device. 5. A network management for performing line management for a line use request from a communication system, a plurality of relay devices connected to the communication system, a terminal device connected to the relay device, and the plurality of terminal devices via the relay device. In the circuit switching network system including a device, the relay unit relays transmission data exchange between the communication system and the terminal device, and the network management device determines the line usage time of each terminal device. A line that has a line monitoring unit for monitoring, and when the line monitoring unit detects that the connection time with the corresponding relay device among the respective terminal devices exceeds a predetermined line use time, the line connected with the terminal device A network system characterized by releasing. 6. The network system according to claim 4, wherein the terminal device sends a line usage request together with a line usage request made before the line acquisition to the network management device,
A network system, wherein the network management device sets a value larger than the scheduled line use time in the line monitoring means as the line use time of the terminal device. 7. The network system according to claim 5, wherein the terminal device sends a parameter value indicating a transfer data amount together with a line use request made before the line acquisition to the network management device, and the network management device based on the parameter value. A network system characterized in that the line use scheduled time is calculated and is set in the line monitoring means as the line use time of the terminal device. 8. The network system according to claim 5, wherein the line monitoring means monitors whether or not the terminal device is in communication, and when the non-communication time exceeds a predetermined line use time, the network A network system in which a management device releases a line connected to the terminal device.