JPH0537528A - Communication network system - Google Patents

Abstract

PURPOSE:To attain memory dump of a bridge even from a terminal equipment of a branch line communication network. CONSTITUTION:A bridge(BR) 3A implementing connection between communication networks is provided to a trunk line communication network. A branch line NW5 is connected via the BR3A and the information or the like required for transmission reception processing of a transmission data between the branch line NW5 and the trunk line NW is stored in a built in memory in the BR3A and the memory content is read with respect to a memory dump request from the trunk line NW and returned to a request source. The BR3A is provided with a command means 4 connecting a prescribed dump request to a terminal equipment 6 able to send it and setting the memory dump command on emergency and when the command means 4 is set to the emergency memory dump command and receives a prescribed memory dump request from the terminal equipment of the branch line NW5, the memory content is dumped and returned to the request source.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication network, and more particularly to a communication network system which enables memory contents of a bridge connecting a trunk LAN and a branch LAN even when the trunk LAN is abnormal.

[0002]

2. Description of the Related Art A local area network (hereinafter referred to as LAN) which is one of communication network systems.
Is a communication network suitable for communication in a relatively narrow area such as a building unit or a factory unit, and has been widely used in recent years. Then, in the LAN, a branch line LAN is connected to a trunk line LAN, and this branch line LAN
There is a form of connecting terminals to. Branch line L to trunk LAN
When connecting ANs, a bridge that is a device for connecting between LANs is used, and two LANs are connected via this bridge.

Generally, a ring-shaped LA is used as a trunk LAN.
N is often used, and a bus LAN is often used as the branch line LAN. In many cases, Ethernet is used as the bus type LAN.

Here, the Ethernet will be briefly mentioned. Ethernet is a typical bus-type LAN, and the network consists of one coaxial cable. CSMA / C
D (Carrier Sense Multiple)
Access / Collision Detecti
data exchange is performed by a method called "on)".

A packet transmitted from a certain node (node capable of transmitting / receiving) is transmitted in two directions on a conductor of a coaxial cable and is transmitted simultaneously to all nodes in the network (broadcast communication). If the destination of the header part of the packet is the node itself, the node takes it in.

Packets typically include bit fields for destination, control, information, error checking, etc. Each node sends a packet on the network without centralized control. This means that each node checks the existence of a packet on the network and can send a packet on the network whenever there is no packet. Therefore, if multiple nodes judge that the network is empty at the same time and send a packet, a packet collision may occur, but each node always receives the signal on the network and the packet data sent by each node. Collation is performed, and if the collation results do not match, it is determined that a collision has occurred. In this case, each node tries to retransmit the data, but the time until retransmission is decided by a random number or the like.

In Ethernet, signals are sent in an unmodulated baseband system, the transfer rate is about 10 Mbps, and the connection with the network is made through a transceiver and a controller.

On the other hand, the trunk LAN bridge, which is a device for connecting between LANs described above, is suitable for connecting between relatively similar LANs, and identifies frames with a constant address width and sequentially transmits them to the other LAN. It has a function, and necessary information and processing software for that purpose are held in a memory built in the trunk LAN bridge, and the function as a trunk LAN bridge is realized by executing processing using these.

Then, the contents of the memory are dumped (output) or written / written to / from the main LAN bridge according to an instruction from the outside (a terminal such as a management device connected to the main LAN).
It has functions such as deleting / changing. Consider the case of dumping the memory contents of the trunk LAN bridge because of the necessity for maintenance.

FIG. 9 shows an example of a conventional system. In FIG. 9, reference numeral 1 is a ring-shaped trunk LAN system 1, and this trunk LAN system 1 is composed of a plurality of stations (stations) 2.
2m are provided, and these are sequentially connected in a ring shape by the transmission path 7 so that information can be transmitted between the stations.

A station is for connecting a host computer, a terminal device or the like, or for connecting a branch LAN, and a packet having an address assigned to a terminal or the like connected to itself as a destination has been transmitted. In this case, in addition to the function of capturing this and sending unrelated packets to the downstream side, it is possible to perform transmission of transmission packets from terminals etc. to the transmission path, monitoring of the transmission path, control of competition, etc. Reference numeral 5 denotes a bus-like branch line LAN, which uses, for example, Ethernet.

The branch line LAN 5 is a station (2c in the example shown in the figure, which has the main LAN bridge 3 built in. However, in this example, the single station has the main LAN bridge 3 for simplification. There is also a structure in which a trunk LAN bridge is provided for each of them, and different branch line LANs are connected to each of them), and data can be exchanged by packet transmission with the trunk LAN transmission line 7 via this bridge 3. ..

Reference numeral 6 denotes a terminal device, which is connected to the branch line LAN 5. Reference numeral 8 denotes a management device connected to the station 2m, which has a keyboard, a display device, a printer, and the like, and can exchange various commands and data with the LAN system.

In such a configuration, the station 2
When it is desired to dump the memory contents of the main LAN bridge 3 of c, the management device 8 of the main LAN system 1 outputs a dump request to the main LAN bridge 3 of the station 2c. This dump request is sent to the station 2m to which the management device 8 is connected.

As a result, the station 2m packetizes this request and relays it to the station 2c via the transmission line 7 of the trunk LAN system. The station 2c that has received this dump request packet has its own main LAN
Recognize that the packet is addressed to the bridge 3 and capture it, and send it to the trunk LAN bridge 3
Bridge 3 dumps the contents of its memory. Then, the dumped contents are packetized into the station 2
Then, the station 2c sends it to the transmission path 7. The station 2m receives the packet of the dump contents, sends it to the management device 8, and causes the management device 8 to output it.

As described above, conventionally, the dump request is packetized and sent to the transmission path 7, received at the station side, and then passed to the main LAN bridge, and the main LAN bridge dumps the memory contents and sends it. The dump is performed because the packet is transmitted to the station to which it belongs and the packet is transmitted from this station to the request source.

According to this conventional system, when a failure occurs in the station 2c or the station 2m and the failure cannot be recovered, even if a dump request is issued from the management device 8 in order to investigate the state of the trunk LAN bridge 3, a dump request is issued. No such packet can be transmitted to the transmission line 7 or the dump request packet cannot be received from the transmission line 7, so that there is a serious problem that the dump cannot be performed.

If the values of the memory of the trunk LAN bridge are to be directly dumped in order to solve these problems, it is necessary to provide the trunk LAN bridge 3 with a dedicated analysis device.

[0019]

As described above, the trunk line LA is used.
In the system in which the branch line LAN is connected to the N system, the main line L
A trunk LAN bridge is used to connect the AN and the branch LAN. And the trunk LAN bridge is the trunk LA
Installed in a station connected to the N system.

The trunk LAN bridge is constructed so that it can dump the contents of its own memory and return it to the request source in response to a dump request sent through the transmission line of the trunk LAN system. The request from the terminal is not accepted. This is to prevent the system from being destroyed by making it possible to access the internal memory of the trunk LAN bridge from any operation terminal indiscriminately.

Therefore, when dumping the memory contents of a certain trunk LAN bridge, a dump request for the trunk LAN bridge (dump request destination trunk LAN bridge) is conventionally issued from the management device which is the operation terminal handled by the system administrator. , This is packetized by the station connected to the management device, sent out to the transmission line of the main LAN, received by the station having the built-in main LAN bridge of the dump request destination, and passed to the main LAN bridge, and the main LAN In this way, the bridge dumps its own memory contents, passes it to the station to which it belongs, and transmits the packet from this station to the dump request source by packet transmission.

According to this conventional apparatus, when a failure occurs in a station having a built-in main LAN bridge of a dump request destination or a station connected to a management device (a dump request source station) and the failure cannot be recovered, the dump request destination Even if a dump request is issued from the management device in order to investigate the state of the trunk LAN bridge, the packet of the dump request cannot be transmitted / received, so that there is a serious problem that the dump cannot be performed.

In order to solve these problems, the main line LAN
In order to directly dump the memory value of the bridge, it is necessary to provide a dedicated analyzer for the trunk LAN bridge. In this case, a dedicated analysis device is provided separately from the management device, and when the number of branch line LANs is large, it is necessary to provide a dedicated analysis device for each trunk LAN bridge. However, since it is unlikely that a station with a built-in trunk LAN bridge or a station connected to a management device will fail and fall into a state where it will not recover, the purpose is to provide an analyzer for a trunk LAN bridge that is rarely used. It is very uneconomical.

Therefore, the object of the present invention is to
In a LAN system in which a branch line LAN is connected to a main line LAN via a main line LAN bridge, even if a failure occurs at a main line LAN station or transmission line, a dedicated analysis device for each main line LAN bridge should be provided. It is another object of the present invention to provide a communication network system capable of dumping the memory contents of each trunk LAN bridge.

[0025]

In order to achieve the above object, the present invention is configured as follows. That is, a bridge for connecting between communication networks is provided in the trunk communication network, the branch line communication network is connected through this bridge, and the bridge transmits transmission data between the branch line communication network and the trunk line communication network. In a communication network system that has a function of storing information necessary for the delivery processing of the internal memory in a built-in memory and reading the memory contents in response to a memory dump request from a trunk communication network and returning it to the dump request source, A terminal device capable of transmitting a predetermined dump request is connected to the branch line communication network, and an instruction means for setting an emergency memory dump instruction is provided in the bridge, and the instruction means is provided with the emergency memory dump instruction setting. When
When a predetermined memory dump request is received from a terminal device of the branch line communication network, it is provided with a function of dumping the memory content and returning it to the dump request source.

[0026]

In the above structure, the branch line communication network is connected to a terminal device capable of transmitting a predetermined dump request, and it becomes necessary to dump the memory contents of the bridge when the main line communication network fails. In this case, the instruction means for setting the emergency memory dump instruction of the bridge is operated to set the emergency memory dump instruction.
Then, when the instruction means is set to the emergency memory dump instruction, when the bridge receives a predetermined memory dump request from the terminal device of the branch communication network, the bridge dumps the memory contents and returns it to the dump request source.

As described above, the present invention is provided with the instruction means for accepting the memory dump request from the branch line communication network, and when the instruction means is set to accept the memory dump request from the branch line communication network. When a predetermined memory dump request is received from the terminal device of the branch line communication network, the memory contents are dumped and returned to the dump request source, so that even if the main line communication network fails and the bridge cannot be accessed from the main line communication network. , You can access the memory of the bridge by using the terminal device of the branch line communication network.

Moreover, since the memory access of the bridge from the terminal device of the branch line communication network is effective only when a predetermined memory dump request is received when set by the bridge instructing means, the access of the branch line communication network can be performed smoothly. The memory access of the bridge from the terminal device can be suppressed and the system can be protected.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 2, 1 is a ring-shaped trunk LAN system, 2a, 2b, 2c, to 2m are stations (stations), 3A is a trunk LAN bridge, and as shown in FIG. A dump designation switch 4 for designating what to do is provided. Reference numeral 5 is a branch LAN, 6 is a terminal device, and 7 is a ring-shaped transmission line of a trunk LAN.

The main LAN system 1 is provided with a plurality of stations 2a, 2b, 2c, ...
In order to transmit information between stations, the stations are connected in a ring shape. A station is used to connect a host computer or terminal device, or to connect a branch line LAN. This is used when a packet whose destination is the address assigned to the terminal connected to itself is transmitted. In addition to the function of taking in and sending out unrelated packets to the downstream side, it is possible to perform transmission of transmission packets from terminals etc. to the transmission path, monitoring of the transmission path, control of competition, etc. The branch line LAN 5 is a bus-like LAN and uses Ethernet, for example.

This branch line LAN 5 is a station (2c in the example in the figure.
In this example, the single station has the built-in main line LAN bridge 3A for simplification, but there is also a case where a plurality of stations are provided with main line LAN bridges and different branch line LANs are connected to the respective stations). Via the main LAN bridge 3A
Data can be exchanged by packet transmission with the transmission line 7.

The terminal device 6 is connected to the branch line LAN 5. Reference numeral 8 denotes a management device connected to the station 2m, which has a keyboard, a display device, a printer, and the like, and can exchange various commands and data with the LAN system.

FIG. 3 is a block diagram showing an example of the configuration of a station having the trunk LAN bridge 3A built therein. In the figure, 21 is a CPU (processor), 22 is a memory, and 23.
Is a receiver and 24 is a transmitter.

The receiving unit 23 receives a transmission signal from the transmission line 7 of the trunk LAN system, and the memory 22 stores a program and data for performing necessary control and processing as a station. Also, CPU
Reference numeral 21 executes a program in the memory 22, performs processing necessary for a station, such as processing received signals from the receiving section 23 and giving transmission data to the transmitting section 24. The transmission data is transmitted to the transmission line 7.

The trunk LAN bridge 3A has a CPU (processor) 31, a memory 32, an input / output unit (I / O) 33, a dump designation switch 4, a transmission / reception unit (T / R) 34, and the like.

The input / output unit 33 is for exchanging data with the station side, and the memory 32 is a main line LAN.
It stores programs and data for performing necessary control and processing as a bridge. In addition, the CPU 31
Executes a program in the memory 32, exchanges data with the input / output unit 33 and the transmission / reception unit 34, and processes received data. The transmitter / receiver 34 is connected to the branch line LAN 5 and exchanges transmission with the branch line LAN 5.

As described above, the main line LAN bridge 3A used in this system is provided with the switch 4 for instructing the memory dump. This switch 4 is an emergency switch and is normally off. When the switch 4 is turned on, the memory dump can be instructed from the connection terminal device 6 of the branch line LAN 5.

The branch line L is connected to the trunk LAN bridge 3A.
When a packet is received from the AN 5, it is confirmed whether or not the switch 4 for designating dumping is on (whether it is on or off), and if it is on (if it is on), a dump is requested. Whether or not the packet is a packet to be sent, and if it is a dump request packet, a function of performing dump processing is provided.

In the dump process, the information about the dump such as the memory address to be dumped and the dump length is read from the packet requesting the dump, and the packet having the dumped contents as the data is created based on the read information. Do what you said to send to. For this reason, a dump response packet is created in the trunk LAN bridge 3A, and the No. It has a function to set (number) in a packet and send it.

When the switch 4 is off, the main line LA
The N-bridge 3A operates in a normal mode, receives a dump request packet from the management device 8, dumps a designated area of the memory 32 based on the contents of this packet, and packetizes and returns it to the request source. This is the same as before. When switch 4 is off, branch line LAN5
Even if the packet of the dump request is sent, it does not react to this and does not return the dump response packet. The function as such a trunk LAN bridge is obtained by causing the CPU 31 to execute the program of the memory 32.

In such a structure, in order to dump the main LAN bridge 3A, in a normal case where there is no abnormality in the stations 2a to 2m and the transmission line 7, the switch 4 is turned off and the above-mentioned prior art is explained. The management device 8 can perform the same process as the above.

On the other hand, the stations 2a to 2m and the transmission line 7
In an emergency where a packet transmission is impossible on the trunk LAN due to an abnormality in the main LAN, when a dump of the memory of the trunk LAN bridge 3A is required, the dump of the trunk LAN bridge 3A is first performed. The switch 4 for specifying that is turned on (ON), the terminal device 6 to the branch line LAN 5
A packet (dump request packet) indicating that dumping is to be performed is transmitted to the trunk LAN bridge 3A via the.

Then, the trunk LAN bridge 3A receives the packet via the transmitting / receiving unit 34, and the CPU 31 of the trunk LAN bridge 3A detects the packet while the dump instruction switch 4 is turned on, and the dump information (start address Information such as the number of bytes to be dumped) and the contents of the memory 32 are dumped based on the dump information, and the dumped data is sent to the terminal device 6 via the branch line LAN 5 as a response packet addressed to the terminal device 6. Send.

Since the above operation is performed, even when the station or the transmission line of the main line LAN fails, the main line LAN
Connection terminal device 6 of branch line LAN 5 connected to bridge 3A
The memory contents of the trunk LAN bridge 3A can be dumped from.

A feature of the system of the present invention is that when the trunk LAN bridge 3A receives a packet from the terminal device 6 connected to the branch LAN 5, it is checked whether or not the packet is a predetermined dump request packet, and a predetermined packet is requested. If it is confirmed that the packet is a dump request packet, the contents of the memory of the trunk LAN bridge 3A are dumped to create a response packet, and the branch line L
Function for processing to send to AN, and branch line LA
This is because the configuration is such that the switch 4 for designating the dumping is designated by N 5 and for enabling the above processing is provided in the trunk LAN bridge 3A.

In the present invention, the bridge is a branch line LAN.
When more packets are received, it is confirmed whether or not the switch 4 for designating dumping is on. If it is on, it is checked whether or not the packet is a packet requesting a dump, and if it is a dump request packet, a dump process is executed. I do.

In the dump processing, the information about the dump such as the address of the memory to be dumped and the dump length is read from the packet requesting the dump, and a packet having the dumped value as data is created based on the read information and sent to the branch line LAN. Therefore, it is possible to perform the dump from the terminal of the branch line LAN regardless of the state of the station or the transmission line of the main line LAN and without using a dedicated analysis device.

Therefore, in a LAN system in which a branch LAN is connected to a trunk LAN via a trunk LAN bridge, even when a failure occurs in a trunk LAN station or a transmission line and the trunk line bridge does not recover, a dedicated trunk LAN bridge is used. The memory contents of each trunk LAN bridge can be dumped without providing an analysis device. FIG. 4 is an example of a flowchart of software relating to emergency memory dump request processing of the trunk LAN bridge 3A in FIGS.

When a packet is received from the branch LAN 5 in FIGS. 1 to 3, first, the trunk LAN bridge 3A checks the state of the self-built-in switch 4 (S10), and the state of the switch 4 is designated to dump. It is determined whether or not (ON or OFF). As a result of the determination, if the switch 4 is turned on, the type area of the packet is read, and it is checked whether or not the packet indicates a request for dumping (S11). As a result, if it is determined that the request is a dump request, the memory content is dumped based on the dump information, and the dump response packet creation processing in which the dump content is captured is performed (S12). If the result of determination in step S10 is that the dump instruction switch has not been turned on,
Processing for a normal packet is performed (S13). FIG. 5 shows details of the dump response packet creation processing in step S12 in the flowchart of FIG.

First, the dump start address and the dump length are read from the dump information included in the dump request packet (S12-1). If the dump length among them is larger than the maximum INFO length of the packet (the maximum length of dump data that can be sent in one packet), step S12-
2. Correct the dump length to the maximum INFO length by S12-3.

Next, in step S12-4, the source address of the dump request packet is read to set it as the destination address of the dump response packet, and the read address is set as the destination address in the response packet. Then, new dump information that has undergone the processing in steps S12-2 and S12-3 is set in the source address area (S12-5).

In step S12-6, a unique value (for example, "0000" is set in the packet type area to indicate that this packet is a response to the dump request.
h "etc .; where h indicates hexadecimal notation) is set.

Furthermore, in steps S12-7 and S12-8, the No. of the bridge that created the dump response packet at the head of the INFO portion of the packet. (Number), station N
o. Set (number) to clarify the source of the packet. Further, in step S12-9, the content of the dump length is read from the dump start address based on the dump information from the memory 32, and the data thus obtained is copied to the INFO portion of the response packet. When the response packet is completed, the packet is transmitted to the branch line LAN 5 in step S12-10.

6 and 7 show an example of the packet format according to the present invention. FIG. 6 shows a format of a packet transmitted from the terminal device 6 shown in FIGS.
It consists of a byte destination address area 6a, a 6-byte source address area 6b, a 2-byte type area 6c, and a 46-byte PAD (filling) area 6d.

Although the format shown in FIG. 6 is an Ethernet format, the destination address 6a is indefinite, so that the dump information is added to this in this system. The type area 6c originally has a value indicating the communication protocol of the INFO part, but here, a unique value is inserted to indicate that this packet is a dump request.

FIG. 7 shows the format of a dump request response packet transmitted from the trunk LAN bridge 3A to the terminal device 6 shown in FIGS. 1 to 3 via the branch LAN 5 shown in FIGS. Destination address area 7a of
6-byte source address area 7b, 2-byte type area 7c, 1-byte station number. Area 7d, 1
Byte bridge No. The area 7e includes a dump data area 7f of 44 to 1498 bytes.

Although the source address is undefined here,
Similar to the case of FIG. 6, dump information is inserted to indicate the dump information of the data in the INFO part (dump start address and dump length information). Further, as in the case of FIG. 6, a unique value for indicating a response to the dump request is entered in the type area.

FIG. 8 shows details of the dump information used in the formats of FIGS. 6 and 7. Of the 6-byte dump information, the first byte is "00h", the second to fourth bytes are the address area ADR, and the second
The byte contents are the bit contents of address data A0 to A7, and the third byte is the address data A8 to A7.
15 bit contents, and the 4th byte is the first 4
The bit contents of A16 to A19 of the address data are entered in the bits, and "0h" is entered in the remaining 4 bits.

As described above, the 20-bit dump start address is placed in the address area ADR in order from the lower bit. The fifth and sixth bytes are the dump length area DL
In this dump length area DL, 16-bit values (“0h” to “5DAh”) are sequentially entered from the lower bit. As an example, from the address “12345h” to “5DA
When dumping h ”bytes, it can be expressed like an Ethernet address as follows: 00-45-23-01-DA-05 (=“ 05DA01234500h ”)

When the type area is set to a value unique to the dump request from the terminal device 6 in this system and a packet is sent to the above address, a dump response packet containing the data dumped from the trunk LAN bridge 3A is sent back. Be done.

As described above, when the trunk LAN fails, the dump instruction switch of the trunk LAN bridge is turned on, and a predetermined dump request packet is transmitted from the terminal connected to the branch LAN, whereby the trunk LAN bridge branches. Since a dump response packet including information obtained by dumping the memory contents is sent back via the LAN, the trunk line L
Even when there is a failure in the AN station or transmission line, the memory contents of the bridge can be dumped without using a dedicated analysis device.
The condition of the bridge can be investigated. Further, since the dump request can be responded by turning on the dump instruction switch of the trunk LAN bridge and transmitting a predetermined dump request packet from the terminal connected to the branch LAN, the terminal connected to the branch LAN It is possible to regulate access requests such as an unnecessarily dump request to the main LAN bridge and protect the system.

In short, according to the present invention, a bridge for connecting the communication networks to each other is provided in the trunk communication network, and the branch line communication network is connected through this bridge, and the bridge connects the branch line communication network and the trunk line communication network. The information necessary for the transfer processing of the transmission data between the two is stored in the built-in memory, and the function to read the memory contents and return it to the dump request source in response to the memory dump request from the trunk communication network is provided. In a communication network system, a terminal device capable of sending a predetermined dump request is connected to a branch communication network, and an instruction means for setting an emergency memory dump instruction to the bridge, and the instruction means Memory dump instruction When set, terminal device of branch line communication network Ri receives a predetermined memory dump request, is characterized in that have a function to return to dump the memory contents to the dump requesting.

A terminal device capable of sending a predetermined dump request is connected to the branch line communication network, and when it becomes necessary to dump the memory contents of the bridge when the main line communication network fails. By operating the instruction means for setting the emergency memory dump instruction of the bridge and performing the emergency memory dump instruction setting, the bridge will be specified from the terminal device of the branch line communication network when this setting is made. When the memory dump request is received, the memory contents are dumped and returned to the dump request source.

As described above, according to the present invention, the instruction means for accepting the memory dump request from the branch line communication network is provided, and the memory dump request from the branch line communication network is set to be acceptable by this instruction means. When a predetermined memory dump request is received from the terminal device of the branch line communication network, the memory contents are dumped and returned to the dump request source, so that even if the main line communication network fails and the bridge cannot be accessed from the main line communication network. , You can access the memory of the bridge by using the terminal device of the branch line communication network.

Moreover, since the memory access of the bridge from the terminal device of the branch line communication network is effective only when a predetermined memory dump request is received when set by the bridge instructing means, it is possible to use the unbridled branch line communication network. The memory access of the bridge from the terminal device can be suppressed and the system can be protected.

The present invention is not limited to the embodiments described above and shown in the drawings, and it is needless to say that the present invention can be appropriately modified and implemented without departing from the scope of the invention.
In the above embodiment, a ring LAN is used as the trunk LAN,
Although the bus-like LAN is used as the branch line LAN, the present invention is applicable to other configurations and is not limited to the LAN and can be applied to other communication network systems.

[0068]

As described above in detail, according to the present invention,
In a LAN system in which a branch line LAN is connected to a main line LAN via a main line LAN bridge, even if a failure occurs at a main line LAN station or transmission line, a dedicated analysis device for each main line LAN bridge should be provided. It is possible to provide a communication network system capable of dumping the memory contents of each trunk LAN bridge.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a main part of the present invention.

FIG. 2 is a system block diagram showing an embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration example of a station having a built-in trunk LAN bridge 3A.

FIG. 4 is a flowchart of emergency memory dump request processing in the trunk LAN bridge 3A.

FIG. 5 is a step S12 in the flowchart of FIG.
6 is a flowchart showing details of the dump response packet creation process in FIG.

FIG. 6 is a diagram showing an example of a packet format.

FIG. 7 is a diagram showing an example of a packet format.

FIG. 8 is a diagram showing details of dump information used in the formats of FIGS. 6 and 7;

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

[Explanation of symbols]

1 ... Trunk line LAN system, 2a-2m ... Station,
3A ... Trunk line LAN bridge, 5 ... Branch line LAN, 4 ... Memory dump instruction switch, 7 ... Transmission path, 8 ... Management device 21, 31 ... CPU (processor), 22, 32 ...
Memory, 23 ... Reception unit, 24 ... Transmission unit, 33 ... Input / output unit, 34 ... Transmission / reception unit.

Claims (1)

Claim: What is claimed is: 1. A bridge for connecting communication networks to each other is provided in a trunk communication network, and a branch communication network is connected through this bridge. A function to retain the information necessary for the transfer processing of the transmission data to and from the communication network in the built-in memory, and to read the memory contents and return it to the dump request source in response to the memory dump request from the trunk communication network. In the communication network system having the above, a terminal device capable of sending a predetermined dump request is connected to the branch line communication network, and an instruction means for setting an emergency memory dump instruction to the bridge, and this instruction Terminal of branch line communication network when means is set to emergency memory dump instruction Upon receiving a predetermined memory dump request from location, communication network system, characterized in that have a function to return to dump the memory contents to the dump requesting.