JP3057119B2 - Identifier assignment method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an identifier assigning method applied to a distributed system using a LAN based on broadcast communication represented by, for example, Ethernet and an apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, a distributed system using a local area network (LAN) is a representative system for realizing distributed processing and parallel processing by a plurality of computers. In such a distributed system, the physical distance between computers (sites) constituting the system is limited to a relatively short distance. However, since such a distributed system can use a communication line having a sufficient capacity and can use most of existing technologies, the system construction is easy. For this reason, distributed systems using LANs have been developed in various places and have been put to practical use.

In such a distributed system, each site is generally recognized by using an identifier such as a site number which is a unique number assigned to the site.
When an identifier is used for recognizing each site, when a new site enters the system, it is necessary to assign a new identifier to the site.

For this reason, various schemes for assigning the above-mentioned identifiers have been conventionally proposed. In these conventional identifier assignment schemes, each site is physically connected to each other by the same number of lines. For example, communication from site i to site j is performed at site i via a communication port of site j via a line. Is assumed to be transmitted only to site j.

However, in a distributed system using a LAN based on broadcast communication represented by Ethernet, the above assumption is not satisfied because each site broadcasts to a plurality of other sites. For this reason, there is a problem that a conventional identifier assignment method cannot be applied to a distributed system using a LAN. That is, in such a distributed system, when new sites to which no identifier has been assigned enter at almost the same time, the identifiers assigned to these new sites cannot be individually notified for each site via the communication line. Because. In other words, in the conventional identifier assignment scheme, only one site to which no identifier is assigned can exist in the distributed system at the same time.

For this reason, in a system using a LAN based on broadcast communication, for example, an identifier is previously assigned to a site newly joining the system, and a user activates each site based on the identifier. Has been adopted.

[0007]

However, in the above-described conventional method of assigning identifiers, it takes too much time to assign identifiers.
There is a problem that unauthorized subscription is performed.

[0008] The present invention has been made in view of such a conventional situation. Even when a new site enters a plurality of sites almost simultaneously while operating a system including a plurality of sites having the same transmission / reception function, an identifier is used. It is an object of the present invention to provide an identifier assigning method and an identifier assigning method capable of assigning an identifier.

[0009]

That is, according to the identifier assigning method of the present invention, a plurality of sites are connected via a communication line, and a partner site is specified by using a unique identifier assigned to each site. In allocating the unique identifier to each site in a communication system that occupies a communication line and performs data communication, each site newly joining the communication system broadcasts an identifier numbering request on the communication line. One of the participating sites that has received the identifier numbering request on the communication line broadcasts, on the communication line, an identifier sequence in which unique identifiers that have not been assigned yet are arranged in the order in which they are received, Each site that joins, after broadcasting the identifier numbering request and before receiving the identifier sequence, receives the number of identifier numbering requests broadcasted by other newly joining sites. Counted, and determines the unique identifier assigned to its site from in the identifier column by count.

Further, according to the identifier assigning method of the present invention, a plurality of sites are connected via a communication line, a partner site is specified using a unique identifier assigned to each site, and the communication line is exclusively used. In allocating the unique identifier to each site in a communication system for performing data communication, each site newly joining the communication system broadcasts an identifier number request on the communication line, and One of the participating sites that received the identifier numbering request
One is to broadcast on the communication line a first identifier sequence in which unique identifiers that have not been assigned are arranged in the order of reception, and to transmit the first identifier sequence after receiving the identifier issuance request. In the case where an identifier numbering request is received from another newly joining site, the number of identifier issuing requests is counted, and the number of identifiers according to the counted value is added to the first identifier column in the order of reception. 2 and broadcast the same on the communication line, each of the newly joining sites, after broadcasting the identifier numbering request until receiving the second identifier sequence, Counting the number of identifier issuing requests broadcast by other newly joining sites, and determining a unique identifier assigned to the own site from the second identifier sequence based on the counted value. I do.

Further, the identifier assigning apparatus of the present invention is connected to a plurality of sites via a communication line, specifies a partner site using a unique identifier assigned to each site, and occupies the communication line exclusively. An identifier allocating device used for a communication system for performing data communication, wherein each site is connected to the communication line to intercept communication on the communication line and transmit / receive necessary data; and Means for transmitting a request for issuing an identifier of a site on the communication line, and an identifier transmitted by another site after the request for transmitting the identifier is transmitted and before receiving an assigned identifier message. Counting means for receiving and counting the number of the numbering requests, confirmation means for confirming the order in which the numbering requests for the identifier are transmitted on the communication line, and identifier message under the control of the confirmation means. And a means for selecting and determining an identifier required for the site from identifier messages received from the communication line under the control of the counting means. It is characterized by the following.

[0012]

According to the present invention, an identifier issuing request is received from another new site during a period from when an identifier issuing site receives an identifier issuing request from a newly joining site to when a unique identifier is transmitted. At that time, the number of the identifier numbering request is counted, and each unique identifier corresponding to the counted number is transmitted to the line, and the newly joining site transmits the identifier issuing request, When an identifier issuance request is received from another new site until a unique identifier is received, the number of the identifier issuance requests is counted, and a unique identifier assigned to the self is determined based on the counted number. Therefore, it is possible to assign an identifier even when a plurality of new sites almost simultaneously enter during system operation.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an identifier assigning method and apparatus according to the present invention.

FIG. 1 is a block diagram showing a part of the configuration of an embodiment of an identifier assigning apparatus according to the present invention. In a communication system to which the present invention is applied, when a site number is not specified at the time of communication, such as Ethernet, a communication method of broadcast communication is applied, and during a certain communication, the communication is performed on a communication line. And a communication method that cannot perform any communication other than that communication is applied.
Therefore, it is assumed that the communication collision on the communication line is prevented. In the present invention, a site number is considered below as a site identifier.

As shown in FIG. 1, a communication line (bus) 1 is connected to a plurality of sites 2a each having the same transmission / reception function. The site 2a has already been assigned a unique site number as an identifier and is a site participating in the communication system (hereinafter referred to as a participating site). On the other hand, the site 2b does not yet have its own site number, and is a site that is about to participate in the communication system (hereinafter, referred to as a participating site). In FIG. 1, for simplicity, one each of the participating site 2a and the participating site 2b is shown.

The participating site 2a includes an identifier issuing unit 20a having a function of issuing a new site number, and an identifier issuing request unit 20b having a function of requesting the issuance of a new site number. The identifier issuing unit 20a includes a communication unit 21a that connects each site to the communication line 1 and constantly intercepts communication on the communication line 1, a site number issuing unit 21b that constructs and issues a site number message of the participating site 2b, and a plurality of identifiers. Participating site 2b sends identifier issuing request to communication line 1
It comprises a communication order confirmation unit 21c that recognizes and stores the order when it is output above.

On the other hand, the identifier issuance requesting unit 20b includes a communication unit 21a, a numbering request transmitting unit 21d for transmitting a request for issuing a site number to its own site on the communication line 1, and After the request is output on the communication line 1 and before the message of the identifier is received, the other site issue request counting unit 21e that counts the number of issue requests output by other sites, and the received identifier sequence It comprises a site number determining unit 21f which selects and determines its own site number based on the output of the other site number request counting unit 21e.

Description of other components required for data transmission / reception via the LAN is omitted for simplicity. The participating site 2b has exactly the same configuration as the participating site 2a, but the identifier issuing unit 20a operates at the participating site 2a, and the identifier issuing requesting unit 20b operates at the participating site 2b.

Among the participating sites 2a that have received the numbering request, the one having the smallest site number (address), for example, can be made to issue a site number by its own identifier issuing unit 20a. Also, in FIG.
a has the same configuration, and each has a numbering function,
Only one specific participant site 2a may logically have a site number issuing function.

FIGS. 2 and 3 show the participating site 2a of FIG.
3 is a flowchart for explaining a series of processes in the identifier assignment. Hereinafter, the identifier assignment processing of the participating site 2a will be described with reference to these flowcharts. As a numbering method, any method can be used as long as it can issue a number other than the number currently assigned to another site in the communication system.
There is a way to increment by one.

In FIG. 2, after the system is started, the communication section 21a of the participating site 2a constantly intercepts the communication on the communication line 1 (S201).

The site number issuing section 21b determines whether or not the intercepted communication is a site number issuing request (S20).
2) If it is not a numbering request, the communication unit 21a continues to intercept the communication on the communication line 1 (S201).

On the other hand, if the communication intercepted by the communication unit 21a is a numbering request, the site number issuing unit 21b issues a site number and prepares a reply (S203).

Next, for example, as shown in FIG. 6, after the i-th participating site 2b issues a numbering request (indicated by an arrow pointing obliquely upward from below in the figure) in step S202,
Before the new site number is issued from the participant site 2a, the communication unit 21a of the participant site 2a issues a numbering request from the other r new participating sites 2b added to the communication system. It is determined whether or not it has been received (S204).

When a new numbering request is received, the site number issuing unit 21b of the participant site 2a issues a site number in response to the numbering request under the control of the communication order confirmation unit 21c ( S205).

On the other hand, if no new numbering request has been received in step S204, the process proceeds to the next processing. The following description will be made on the case where i + r total numbering requests have been received. The site number issuing unit 21b issues site numbers in the order received, generates a sequence of identifiers having a total of i + r site numbers as elements, and then, as shown in FIG. Phase flag 1 indicating that the site number is provisionally determined
An i + r + 2 element message to which (ie, phase 1) is added is sent as a reply (S206).

Here, the i + r + 2 element message is defined as a message comprising the sum of the number i + r of identifiers and two phase flags. This message is broadcast on the communication line 1 by the communication unit 21a.

Next, referring to FIG. 3, the participating site 2a
Between the time when the site number issuing unit 21b requests the transmission of the i + r + 2 element message to the communication unit 21a and the time when this message is sent out on the communication line 1,
As shown in FIG. 7, there is a numbering request from m new participating sites 2 b, and a numbering request for the participating site 2 b (indicated by an arrow diagonally upward from the bottom in the figure) and the participating site 2 a (Indicated by an arrow diagonally from top to bottom in the figure) collides with the site number issuance in the participating site 2a.

In FIG. 3, i + r participating sites 2b
Is issued from the m new participating sites 2b after the numbering request, the collision caused by the m number of requesting requests causes the communication unit 21a to send i to the communication line 1.
It is determined whether the transmission of the + r + 2 element message has failed (S207).

If the transmission fails due to the m number of numbering requests, a new site number is issued in the same procedure as described above (S208, S209, S210). As a result, under the control of the communication order confirmation unit 21c, the site number issuing unit 21b of the participant site 2a adds the current m site number columns to the i + r site number columns as shown in FIG. Is added, and a phase flag 2 is added before and after the site number column, and an i + r + m + 2 element message is transmitted as a reply, and the communication unit 21a retransmits this message onto the communication line 1 (S211).

The phase flag 2 is a flag indicating that the site number in the site number sequence is the site number finally determined for each site. The collision detection processing and the site number sequence retransmission processing are automatically executed by the hardware of the participating site 2a. The fact that the retransmission processing has been performed can be known from the participation site 2b by the value of the phase flag being “2”. Then, step S2
Subsequent to step 11 or if the transmission has not failed due to no collision in step S207, a site number determination notification is broadcasted on the communication line 1 (S212), and the process of assigning the identifier of the participating site 2a is performed. Is completed.

FIGS. 4 and 5 are flowcharts for explaining a series of processes in assigning identifiers of the participating sites 2b in FIG. Hereinafter, the processing of the participating site 2b will be described with reference to FIGS.

In FIG. 4, prior to the issue request, the participating site 2b has its own other site issue request counting section 21e.
Is initialized to "0", and its own phase flag (myphase) is set to "1" to indicate that it has entered the initial stage of the process of site number assignment (S301).

Thereafter, the numbering request sending section 21d sends a numbering request to the participating site 2a via the communication section 21a and the communication line 1 (S302).

The communication section 21a of the participating site 2b starts interception of communication on the communication line 1 to receive a reply message from the participating site 2a (S303).

The communication section 21a determines whether or not there is a number notification of its own participating site 2b in the intercepted message (S304).

When there is no issuing number notification to itself and another new participating site 2b other than itself sends a site number issuing request (S305), the other site issuing request counting section 2
1e counts the number of site number issuing requests, and sequentially replaces the count value X with X + 1 (S306).

If there is no issue request from another site, the process waits until there is an issue notice to its own participating site 2b (S30).
4).

Upon receiving the issue notification, the flow shifts to the processing of FIG. First, it is determined whether the phase flag (my-phase) is “2” and the received message includes a site number determination notification (S307).

If the phase flag (my-phase) is "2" and the received message includes the site number determination notification, the process is terminated. In this case, the phase flag (my-phase) is set to "1". And the participating site 2a is shown in FIG.
In the following, a description will be given of a case where the temporarily assigned site number is returned according to the procedure described in (1). In this case, the received message is an i + r + 2 element message composed of i + r site numbers and two phase flags “1” allocated to the participating site 2b including itself, as described above (S308).

Next, it is determined whether the phase flag of the received message is different from its own phase flag (my-phase) (S309), and the phase flag of the received message is different from its own phase flag (my-phase). In this case, the communication on the communication line 1 is intercepted (S310).

Here, since the phase flag (my-phase) is "1" and the phase flag of the received message is also "1", the processing shifts to the next processing, and the site number determination unit 21f counts first. Search for own site number candidates from the count value X of the issue number from another site (S31)
1). That is, as shown in FIG. 8, the value of the (i + r−X + 1) th element from the head of the i + r + 2 element message, that is, the value of the (X + 2) th element from the back is the participating site 2 of the own message.
Let it be a temporary site number assigned to b.

Next, it is determined whether the phase flag (my-phase) is "1" (S312). If the phase flag (my-phase) is not "1" (if "2"), the process is terminated. I do.

In this case, since the phase flag is "1", to enter the state where the main decision is made next, the own phase flag is set to "2" (S313), and the communication section 21a again sets the communication line. 1 on the communication (S31)
4).

When the next message is received in this state, the process returns to step S307. Here, since the phase flag (my-phase) has already been set to “2”, when the received message decision notification is received from the participating site 2a,
The site number obtained so far is determined as its own site number, and the process ends.

On the other hand, when no decision notice is received, that is,
When the next message with the phase flag of “2” is received, steps S307, S308,
The procedure of S309, S311, and S312 is repeated, a new site number is obtained, and the process ends. in this case,
The temporary site number obtained from the message whose phase flag is “1” is ignored.

As described above, according to this embodiment, it is possible to assign a site number even when a plurality of new sites almost simultaneously enter during the operation of the communication system. In addition, since the identifier can be checked at both the participating site and the participating site, and the number of subscriptions can be checked at the counter, unauthorized participation at the participating site can be prevented.

[0048]

As described above, according to the present invention,
When a system including a plurality of sites having the same transmission / reception function is in operation, a new site can be assigned an identifier even when a plurality of new sites almost simultaneously enter.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a part of the configuration of an embodiment of an identifier assigning apparatus according to the present invention.

FIG. 2 is a flowchart for explaining processing in assigning identifiers of participating sites in FIG. 1;

FIG. 3 is a flowchart for explaining processing in assigning identifiers of participating sites in FIG. 1;

FIG. 4 is a flowchart for explaining processing in assigning identifiers of participating sites in FIG. 1;

FIG. 5 is a flowchart for explaining processing in assigning identifiers of participating sites in FIG. 1;

FIG. 6 is a diagram for explaining an identifier assignment process over time.

FIG. 7 is a view for explaining an identifier assignment process as time passes.

FIG. 8 is a diagram exemplifying an identifier sequence issued from a participating site;

FIG. 9 is a diagram exemplifying an identifier sequence issued from a participating site;

[Explanation of symbols]

 1 Communication Line (Bus) 2a Participated Site 2b Participating Site 20a Identifier Issuing Unit 20b Identifier Issuing Request Unit 21a Communication Unit 21b Site Number Issuing Unit 21c Communication Order Checking Unit 21d Issuing Request Sending Unit 21e Other Site Issuing Request Counting Unit 21f Site number determination unit

Claims (3)

(57) [Claims] 1. A communication system in which a plurality of sites are connected via a communication line, a partner site is specified using a unique identifier assigned to each site, and data communication is performed exclusively by using the communication line. Upon assigning the unique identifier to each site, each site newly joining the communication system broadcasts an identifier numbering request on the communication line and receives the identifier numbering request on the communication line. One of the participating sites broadcasts, on the communication line, an identifier sequence in which the unique identifiers that have not been allocated are arranged in the order of reception, and each of the newly joining sites broadcasts the identifier numbering request. Until the identifier string is received after transmission, the number of identifier issuing requests broadcast by other newly joining sites is counted, and the counted value is used to change the identifier string to the own site from the identifier string. An identifier assignment method characterized by determining an assigned unique identifier. 2. A communication system in which a plurality of sites are connected via a communication line, a partner site is specified using a unique identifier assigned to each site, and data communication is performed exclusively using the communication line. Upon assigning the unique identifier to each site, each site newly joining the communication system broadcasts an identifier numbering request on the communication line and receives the identifier numbering request on the communication line. One of the participating sites broadcasts, on the communication line, a first identifier sequence in which unique identifiers that have not been allocated are arranged in the order of reception, and after receiving the identifier issuance request, transmits the first identifier sequence. If an identifier numbering request is received from another newly joining site before transmission, the number of the identifier issuing requests is counted, and the number of identifiers according to the counted value is determined as the first identification number in the receiving order. A second identifier string added to the separate string is configured and broadcasted on the communication line, and each of the newly joining sites broadcasts the identifier numbering request and then transmits the second identifier string. Until receiving, count the number of identifier numbering requests broadcast by other newly joining sites,
An identifier assigning method comprising: determining a unique identifier assigned to the own site from the second identifier sequence based on the count value. 3. A communication system in which a plurality of sites are connected via a communication line, a partner site is specified using a unique identifier assigned to each site, and data communication is performed exclusively using the communication line. An identifier allocating device to be used, wherein each site is connected to the communication line to intercept communication on the communication line and transmit / receive necessary data. Means for transmitting an identifier numbering request, and receiving the identifier numbering request number transmitted by another site between the time when the identifier numbering request is transmitted and the time when the assigned identifier message is received. Counting means for counting, confirming means for confirming the order in which the request for issuing the identifier is transmitted on the communication line, and forming an identifier message under the control of the confirming means, and issuing the identifier message on the communication line And means for selecting and determining an identifier required for the site from identifier messages received from the communication line under the control of the counting means.