JPH07283828A - Terminal address setting mechanism - Google Patents

Abstract

PURPOSE:To prevent a network fault in advance due to duplicate setting or non-definition of an address by setting automatically a station address by the CSMA/CD access method. CONSTITUTION:A transmission success storage section 26-1 of an address managed terminal equipment 2-1 stores a transmission success when an address request frame generated by an address request frame generating section 25-1 is sent without collision on a transmission line 10. When the transmission success is stored in the transmission success storage section 26-1, a data reception section 24-1 receives an address provision frame from an address management terminal equipment 1. An address extract section 27-1 extracts an address from the address provision frame and stores it to an address storage section 28-1 as an address of its own station.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal address setting mechanism, and more particularly to a CSMA / CD access method (ISO 880).
The present invention relates to a terminal address setting mechanism of a local area network (LAN) which performs communication between a plurality of stations via a common transmission line based on 2/3).

[0002]

2. Description of the Related Art Conventionally, in a local area network based on the CSMA / CD access method, the station address of each terminal connected to a common transmission line is manually set.

Station addresses have been manually set in networks other than the local area network based on the CSMA / CD access method.
This manual setting of the station address is time-consuming, and the station address is apt to be erroneously set.

For this reason, station address setting commands are sequentially transmitted in one direction, 1 is added to the station address set in the own station, and the station address is sent to an adjacent station, thereby avoiding erroneous station address setting. There is a method that allows the station address to be set automatically. This method is described in JP-A-2-828.
No. 41 publication.

[0005]

DISCLOSURE OF THE INVENTION The conventional CSM described above
In a local area network based on the A / CD access method, maintenance personnel manually enter the set addresses of each station one by one after network construction is completed or after a new terminal is connected to an operating network. There is.

Therefore, the larger the network, the longer it takes to set the station address, and the operation cannot be started easily. Also, the address is 4
Since it is as long as 8 bits, it is easy to make an input error, and even if the operation starts, the system will not operate normally easily due to failures such as address duplication and address undefined due to setting mistakes.

In order to solve this problem, CSMA / C
Even if an address setting method in a network other than the local area network based on the D access method is used, the above method must make the transmission path unidirectionally transmittable. It cannot be applied as it is to a local area network based on the CSMA / CD access method for transmission / reception, and if it is applied, a dedicated transmission path capable of transmitting in one direction must be prepared.

Therefore, an object of the present invention is to solve the above problems, to enable automatic setting of a station address in the CSMA / CD access method, and to prevent a network failure due to an address duplication setting due to a human error or undefined. It is to provide a terminal address setting mechanism that can be prevented in advance.

[0009]

A terminal address setting mechanism according to the present invention includes a common transmission line connecting an addressed management terminal and an address management terminal managing an address of the addressed management terminal, A terminal address setting mechanism of a local area network that transmits and receives data depending on the presence or absence of a collision on the road, and means for transmitting an address request frame to the addressed management terminal on the transmission path when the power is turned on, and the address request. Storage means for storing the successful transmission of the frame, means for receiving an address assignment frame from the address management terminal on the transmission path based on the contents of the storage means, and extracting an address from the received address assignment frame. The address management terminal has means for holding it as an address of its own station, and the collision occurs at the address management terminal. Means for detecting whether or not a frame received without receiving the address request frame is stored in association with an address to be given to the address-managed terminal and flag information indicating whether or not the address is in use. An address table and means for transmitting the address assignment frame generated by using an unused address in the address table when the address request frame is detected, to the transmission path.

In addition to the above configuration, the terminal address setting mechanism according to the present invention responds to the address request frame from another addressed management terminal until the address assignment frame is normally received by the addressed management terminal. The address management terminal is provided with means for generating the collision and forcibly destroying the address request frame.

[0011]

Function: The addressed management terminal transmits an address request frame when the power is turned on. When the address management terminal receives the address request frame without causing a collision on the transmission path, the addressed management terminal holds that fact, that is, the successful transmission of the address request frame.

When the address management terminal receives the address request frame from the address-managed terminal without causing a collision on the transmission path, the address management terminal generates an address assignment frame by using the unused address in the address table and transmits it on the transmission path. .

During this time, the address management terminal causes a collision with an address request frame from another address managed terminal, and destroys an address request frame from another address managed terminal.

When the address management terminal receives the address assignment frame from the address management terminal upon successful transmission of the address request frame, it extracts the address from the address assignment frame and holds it as the address of its own station.

As a result, the address management terminal can process the address request from the address-managed terminal one by one and set the station address to the address-managed terminal.

Therefore, it is possible to automatically set the station address in the CSMA / CD access method, and prevent the network failure due to the duplicated setting of the address due to a human error or the undefined condition.

[0017]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the system configuration of an embodiment of the present invention. In the figure, a common transmission line 10
Address management terminals 2-1 to 2-3 and an address management terminal 1 that manages the station address of each of the address management terminals 2-1 to 2-3 are connected to the address 0.

FIG. 2 is a block diagram showing the configuration of the address management terminal 1 of FIG. In the figure, the address management terminal 1 includes a central processing unit 11, a data transmission unit 12, a collision detection unit 13, a collision generation unit 14, a data reception unit 15,
Addressing frame generation unit 16 and frame analysis unit 1
7 and an address table 18.

The data transmission unit 12 transmits the data such as the addressing frame generated by the addressing frame generation unit 16 onto the transmission path 100. The address assignment frame generator 16 generates an address assignment frame using the contents of the address table 18 and sends it to the data transmitter 12.

In the address table 18, an address to be given to the addressed terminals 2-1 to 2-3 and a flag indicating whether or not the address is in use are stored in association with each other.

The collision detector 13 detects a collision of data or the like on the transmission line 100, and the collision generator 14 detects the collision of the transmission line 10.
On the 0, a signal for causing a collision of data or the like is transmitted.

The data receiving section 15 receives data on the transmission path 100. The frame analysis unit 17 is a data reception unit 15.
Then, it is analyzed whether or not the data received on the transmission path 100 without collision of data is an address request frame.

FIG. 3 is a diagram showing the structure of the address table 18 shown in FIG. In the figure, the address table 18 has an area 18a for storing a flag indicating whether or not the address is in use, and addresses "000001", "000002", which should be given to the address-managed terminals 2-1 to 2-3.
An area 18b for storing "000003", "000004", ...

The flag stored in the area 18a is set to "1" when the corresponding address is in use, and is set to "0" when the corresponding address is unused. The address table 18 is composed of a memory such as a RAM.

FIG. 4 is a block diagram showing the configuration of the address-managed terminal 2-1 of FIG. In the figure, the address management terminal 2-1 includes a central processing unit 21-1, a data transmission unit 22-1, a collision detection unit 23-1, and a data reception unit 2
4-1, an address request frame generation unit 25-1, a transmission success storage unit 26-1, an address extraction unit 27-1,
It is composed of an address holding unit 28-1 and a power switch 29-1.

The data transmission unit 22-1 transmits the data such as the address request frame generated by the address request frame generation unit 25-1 onto the transmission path 100. The address request frame generator 25-1 generates an address request frame for setting the station address of its own terminal and sends it to the data transmitter 22-1.

The collision detector 23-1 is a data transmitter 22-
Transmission line 1 after the address request frame is transmitted from
When a collision of data or the like on 00 is detected, the fact is output to the successful transmission storage unit 26-1. Successful transmission storage unit 2
6-1 is the collision detection unit 23-1 after the address request frame is transmitted from the data transmission unit 22-1 to the transmission line 100.
The fact that no collision of data or the like is detected, that is, the successful transmission is stored.

The data receiving section 24-1 receives the data on the transmission path 100. The address extracting unit 27-1 extracts an address from the address-added frame received by the data receiving unit 24-1 on the transmission path 100 without collision of data or the like, and sends the address to the address holding unit 28-1. The address holding unit 28-1 is the address extracting unit 27-
The address extracted in 1 is held as the station address of the own terminal.

Although not shown, the configuration of the addressed management terminals 2-2 and 2-3 is the same as that of the addressed management terminal 2-1 shown in FIG. The operation is the same as that of each unit of the address management terminal 2-1.

FIG. 5 is a diagram showing a format of a frame transmitted / received in the physical layer based on the CSMA / CD access method.
In the figure, a frame a includes a destination address part a1 having a length of 6 bytes, a source address part a2 having a length of 6 bytes, a data part a3 having a length of 48 bytes or more and a length of 1502 bytes or less,
It is composed of a 4-byte frame check sequence part a4.

FIG. 6 is a diagram showing the structure of an address request frame generated by the address request frame generator 25-1 of FIG. In the figure, the address request frame b is 6
A destination address part b1 having a byte length, a source address part b2 having a 6-byte length, a data part b3 having a 16-byte length, and 4
It is composed of a byte-length frame check sequence part a4.

The above address request frame b is an example, and the broadcast address (all'F ') is set in the destination address part b1 and all' 0 'is set in the source address part b2. It Further, the contents of the source address part b2 and the size of the data part b3 can take other values.

Further, a bit pattern indicating that it is the address request frame b is set in the data part b3. What kind of pattern is provided if this bit pattern indicates the address request frame b and can be distinguished from other patterns? But it's okay.

FIG. 7 is a diagram showing the structure of the address assignment frame generated by the address assignment frame generator 16 of FIG. In the figure, the addressing frame c has a 6-byte length destination address part c1, a 6-byte length source address part c2, a 16-byte length data part c3, a 6-byte length data part c4, and a 4-byte length. Frame check sequence section c5.

The above-mentioned address assignment frame c is an example. The broadcast address (all'F ') is set in the destination address part b1, and the address of the address management terminal 1 is set in the source address part b2. Set. Also,
The sizes of the data parts c3 and c4 can take other values.

Further, a bit pattern indicating that the frame is an address-added frame c is set in the data portion c3, and the addressed management terminals 2-1 to 2-
A bit pattern indicating the address to be assigned to 3 is set. As the bit pattern indicating the addressing frame c, any pattern may be used as long as it indicates the addressing frame c and can be distinguished from other patterns.

FIG. 8 is a flowchart showing the operation of the address-managed terminal 2-1 shown in FIG. These FIG. 1 and FIG.
The operation of the address-managed terminal 2-1 will be described with reference to FIG.

When the power switch 29-1 is pressed and the power of the address management terminal 2-1 is turned on (step S1 in FIG. 8), the address request frame generator 25-1 is controlled by the central processing unit 21-1. Then, the address request frame b is generated (step S2 in FIG. 8), and the data transmitter 22
-1 is transmitted on the transmission path 100.

After this, the collision detection unit 23-1 determines whether the address request frame b transmitted from the data transmission unit 21-1 is received by the address management terminal 1 without colliding with other data on the transmission path 100. , That is, whether or not the address request frame b has been successfully transmitted to the address management terminal 1 (step S3 in FIG. 8).

When the collision detection unit 23-1 determines that the address request frame b has been successfully transmitted to the address management terminal 1, it outputs an instruction to the successful transmission storage unit 26-1 to transmit the address request frame b to the address management terminal 1. The success is stored (step S4 in FIG. 8).

When the collision detection unit 23-1 determines that the transmission of the address request frame b to the address management terminal 1 has failed, the process returns to step S2 and the transmission of the address request frame b to the address management terminal 1 succeeds. Continue to retry until you do.

When the address management terminal 2-1 succeeds in transmitting the address request frame b to the address management terminal 1, the address assignment frame c from the address management terminal 1 is sent.
Is in a transmission waiting state (step S5 in FIG. 8).

The data receiving section 24-1 receives the address assignment frame c from the address management terminal 1 via the transmission line 100.
When the address request frame b is successfully transmitted to the address management terminal 1 by referring to the transmission success storage unit 26-1, the received address assignment frame c is sent to the address extraction unit 27-1. .

The address extractor 27-1 extracts an address from the data part c4 of the address-added frame c and uses the address as the address of its own terminal in the address holder 28-.
It is held at 1 (step S6 in FIG. 8).

The address holding unit 28-1 holds the address until the power is turned off. Further, the addressee-managed terminal 2-1 ignores all addressing frames received thereafter via the transmission path 100 (step S7 in FIG. 8).

The other address-managed terminals 2-2,2-
3 is the same as the operation of the address-managed terminal 2-1 described above, and is sent from the address-managed terminal 1 to the other address-managed terminals 2-2 and 2-3 when the address request frame b is successfully transmitted. The incoming address is retained.

FIG. 9 is a flow chart showing the operation of the address management terminal 1 of FIG. 1 to 3 and 5 to
The operation of the address management terminal 1 will be described with reference to FIGS. 7 and 9.

The address management terminal 1 constantly monitors the data on the transmission path 100, and determines whether or not a collision is detected by the collision detection unit 13 when the data reception unit 15 receives a frame (FIG. 9). Step S11).

When the collision detecting unit 13 determines that no collision is detected, the frame received by the data receiving unit 15 is sent to the frame analyzing unit 17, and the frame analyzing unit 17 receives the addressed terminals 2-1 to 2-3. It is determined whether or not it is the address request frame b from (step S12 in FIG. 9). The frame analysis unit 17 includes the address-managed terminals 2-1 to 2-3.
If it is determined that the address request frame b is from the address request frame b, the fact is reported to the central processing unit 11.

The central processing unit 11 has an address table 18
, An arbitrary one address is selected from the addresses indicating that the flag is unused (“0”), and the address assignment frame generation unit 16 is instructed to generate the address assignment frame c.

The addressing frame generator 16 generates an addressing frame c using the address selected by the central processing unit 11 (step S15 in FIG. 9) and transmits it from the data transmitter 12 onto the transmission path 100 (FIG. 9). 9 step S16).

The central processing unit 11 determines whether or not the transmission of the address assignment frame c has been successful depending on whether or not the collision detection unit 13 detects a collision during the transmission of the address assignment frame c (step S17 in FIG. 9). .

When the central processing unit 11 determines that the address-giving frame c has been successfully transmitted, the flag ("1" indicating that the address table 18 is in use corresponds to the address set in the data part c4 of the address-giving frame c. ") Is set (step S18 in FIG. 9).

After that, the central processing unit 11 executes the step S1.
The process returns to the process 1 and waits for the next address request frame b. Further, when the address assignment frame c collides and the transmission fails, the central processing unit 11 returns to the process of step S116 and continues the retry until the transmission of the address assignment frame c succeeds.

On the other hand, when the central processing unit 11 receives another address request frame b via the transmission path 100 before transmitting the address assignment frame c (step S1 in FIG. 9).
3) The collision generator 14 is instructed to generate a jam signal, and the jam signal intentionally destroys another address request frame b (step S14 in FIG. 9).

As described above, the address request frame b
In the address-managed terminals 2-2 and 2-3 other than the address-managed terminal 2-1 that first succeeded in sending the address request frame b until the address-managed terminal 2-1 successfully receives the address assignment frame c. Will never be sent successfully. That is, the successful transmission of the address request frame b is not stored in the successful transmission storage units 26-2 and 26-3 (not shown) in the addressed terminals 2-2 and 2-3.

Therefore, the address-managed terminals 2-2, 2-
In 3, the address assignment terminal 1 sends the address assignment frame c
Is sent, the address cannot be extracted and held from the address-added frame c. Therefore, one address is held by a plurality of addressee-managed terminals, that is, an overlapping definition of addresses never occurs.

FIG. 10 is a sequence chart showing the operation of the system in one embodiment of the present invention. These Figure 1
The processing operation in the system according to the embodiment of the present invention will be described with reference to FIG.

If the powers of the addressed management terminals 2-1 to 2-3 are turned on almost at the same time, the address request frames b-1 to b-from the addressed management terminals 2-1 to 2-3.
3 are transmitted to the address management terminal 1 almost all at once.

These address request frames b-1 to b
-3 is normally received by the address management terminal 1, and in this case, the address management terminal 2-
It is assumed that the address request frame b-1 from 1 is normally received.

At this time, the address request frame b-1 is stored in the transmission success storage unit 26-1 of the address-managed terminal 2-1.
Since the successful transmission of is stored, the address-managed terminal 2-
At 1, the address assigning frame c transmitted from the address management terminal 1 can be received.

On the other hand, the address management terminal 1 tries to transmit the address assignment frame c to the address-managed terminal 2-1. During this time, the address-managed terminal 2-2,2-
Even if 3 retransmits the address request frames b-2 and b-3, these frames are destroyed by the jam signal from the collision generator 14.

After that, when the transmission of the address assignment frame c from the address management terminal 1 to the address management terminal 2-1 succeeds, the address management terminal 2-1 extracts the address from the address assignment frame c and outputs its own terminal. It is held in the address holding unit 28-1 as the address of the.

At this time, the addressed terminals 2-2, 2-
3 also receives the address assignment frame c from the address management terminal 1, but the address success frame 26-2, 26-3 (not shown) of the addressed management terminal 2-2, 2-3 does not receive the address request frame. Since the successful transmissions of b-2 and b-3 are not stored, the address cannot be extracted from the address assignment frame c and held as the address of the own terminal.

After that, the address-managed terminal 2-1 ignores the address-giving frame c from the address management terminal 1 and enables normal data communication.

The address management terminals 2-2 and 2-3 also repeat the above operation with the address management terminal 1 so that the address of the own terminal is stored in the address holding unit 28-.
2, 28-3 (not shown) are sequentially held. As a result, the address-managed terminal 2-connected to the transmission path 100
Addresses 1 to 2-3 are automatically determined.

As described above, the address-managed terminals 2-1 to 2-3 connected to the transmission line 100 are automatically set to unique addresses when the power is turned on. Therefore, the user can automatically set the station address without manually setting it, and it is possible to prevent a failure due to an address duplication or an address undefined due to an artificial setting error.

As described above, when it is detected that the frame received without any collision is the address request frame from the address-managed terminals 2-1 to 2-3, the address management terminal 1 stores in the address table 18. The transmission line 1 is an address-assigned frame generated using an unused address.
00, and the address is extracted from the address assignment frame from the address management terminal 1 received when the address management terminals 2-1 to 2-3 have successfully transmitted the address request frame, and used as the address of the own station. By holding the address management terminal 1, the address management terminal 1 processes the address requests from the addressed management terminals 2-1 to 2-3 one by one, and sets the station address to the addressed management terminals 2-1 to 2-3. can do.

Therefore, it is possible to automatically set the station address in the CSMA / CD access method and prevent the network failure due to the duplicated setting of the address due to a human error and the undefined condition.

Further, a collision occurs with address request frames from other address managed terminals 2-1 to 2-3 until the address assignment frame is normally received by the addressed terminals 2-1 to 2-3. By causing a collision by the jam signal from the unit 14 and forcibly destroying the address request frame, it is possible to prevent duplicate setting of the station address.

[0072]

As described above, according to the terminal address setting mechanism of the present invention, the address management terminal is detected when it is detected that the frame received without collision occurs from the address management terminal. The address assignment frame generated by using the unused address in the address table is transmitted on the transmission path, and the address is extracted from the address assignment frame received from the address management terminal when the address request frame is successfully transmitted, and the address of the own station is extracted. By holding as, it is possible to automatically set the station address in the CSMA / CD access method, and it is possible to prevent the network failure due to the duplicated setting of the address or undefined.

Further, according to another terminal address setting mechanism of the present invention, a collision occurs with an address request frame from another address-managed terminal until the address-added frame is normally received by the address-managed terminal. Then, by forcibly destroying the address request frame, it is possible to prevent address duplication settings from occurring.

[Brief description of drawings]

FIG. 1 is a block diagram showing a system configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an address management terminal shown in FIG.

FIG. 3 is a diagram showing a configuration of an address table shown in FIG.

4 is a block diagram showing a configuration of an address-managed terminal of FIG.

FIG. 5 is a diagram showing a format of a frame transmitted / received in a physical layer based on the CSMA / CD access method.

6 is a diagram showing a configuration of an address request frame generated by an address request frame generation unit in FIG.

FIG. 7 is a diagram showing a configuration of an address assignment frame generated by the address assignment frame generation unit of FIG.

8 is a flowchart showing an operation of the address-managed terminal of FIG.

9 is a flowchart showing an operation of the address management terminal of FIG.

FIG. 10 is a sequence chart showing a processing operation in the system according to the embodiment of the present invention.

[Explanation of symbols]

 1 Address Management Terminals 2-1 to 2-3 Addressed Management Terminals 11, 21-1 Central Processing Unit 12, 22-1 Data Transmission Section 13, 23-1 Collision Detection Section 14 Collision Generation Section 15, 24-1 Data Reception 16 address assigning frame generating unit 17 frame analyzing unit 18 address table 25-1 address request frame generating unit 26-1 successful transmission storage unit 27-1 address extracting unit 28-1 address holding unit

Claims (4)

[Claims] 1. A local communication system that includes a common transmission line connecting an address-managed terminal and an address management terminal that manages the address of the address-managed terminal, and that transmits and receives data depending on the presence or absence of a collision on the transmission path. A terminal address setting mechanism of an area network, comprising means for transmitting an address request frame on the transmission path when the power is turned on to the address-managed terminal, storage means for storing successful transmission of the address request frame, and the storage A means for receiving an address assignment frame from the address management terminal on the transmission path based on the contents of the means, and a means for extracting an address from the received address assignment frame and holding it as an address of the own station, The frame received without the collision is sent to the address management terminal by the address request frame. Means for detecting whether an address request frame is detected, an address table for storing an address to be given to the address-managed terminal and flag information indicating whether the address is in use, in association with each other, and detecting the address request frame. A terminal address setting mechanism, characterized in that it has means for transmitting the address assignment frame generated using an unused address in the address table onto the transmission path. 2. The address request frame is forcibly generated by causing the collision with the address request frame from another address managed terminal until the address assigned frame is normally received by the addressed terminal. The terminal address setting mechanism according to claim 1, characterized in that the address management terminal has means for destroying it. 3. The address request frame is a broadcast address whose destination address indicates transmission to all terminals connected to the transmission path.
Alternatively, the terminal address setting mechanism according to claim 2. 4. The address assignment frame is a broadcast address whose destination address indicates transmission to all terminals connected to the transmission path.
4. The terminal address setting mechanism according to claim 3.