JP2000124907A - Communication system having transmission line switch function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speedily switch a transmission line when any abnormality occurs on the transmission line. SOLUTION: A route information definition table 12 holds route information showing which one of sub networks 8 and 10 is to communicate with a client 6 and in the case of communicating with the client 6, a communication control part 14 investigates the route information held in the route information definition table 12 and communicates with the client 6 through a communication port 24 or 26 by the transmission line expressed by the route information. A transmission line monitoring part 20 monitors whether a switching hub device 28 is normal or not through the communication port 24 and when it is discriminated as a result of monitoring due to the transmission line monitoring part 20 that the switching hub device 28 is abnormal, a route information change part 22 changes the route information held in the route information definition table 12 into route information expressing the performance of communication with the client 6 through the sub network 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission line switching function that includes an active transmission line and a standby transmission line, and switches to the standby transmission line to perform communication when an abnormality occurs in the active transmission line. The present invention relates to a communication system having

[0002]

2. Description of the Related Art Conventionally, a large-scale store system includes at least one store server device (also simply referred to as a store server) including a computer and a plurality of POS registers and the like including a computer. A store premises network is formed by including a device (also referred to simply as a client), and data is normally transmitted and received between the store server and the client using the TCP / IP protocol. In the store system, for efficient operation of the store, the store server and the client constantly communicate, and, for example, information and prices of sold products are accumulated in the store server in real time. Therefore, it is not permissible to interrupt the communication for a long time due to a communication failure, and in many cases, the transmission path connecting the store server and the client is duplicated. In addition, since the store system communicates with another store system or management center in a remote place, a router is often used.

[0003] In such a store system, switching of a duplicated transmission line is conventionally performed as follows. That is, the store server holds the routing information indicating the communication path, and usually, when communicating with the client, specifies the transmission path to be used from the routing information based on the communication address information of the other party. The communication message is sent to the client through the transmission path. Then, when a failure occurs in the transmission path, the routing information is temporarily deleted, and the routing information is updated to perform communication using the spare transmission path.

[0004]

However, in a conventional store system, RIP (Routi) is used as a communication protocol.
Since the ng Information Protocol (RFC1058) is used, it takes at least 5 minutes from the occurrence of a failure in a transmission path to the deletion of the routing information, and during that time, communication between the store server and the client. Becomes impossible. As described above, in the store system, the store server and the client need to communicate in real time, and the interruption of the communication for five minutes or more greatly affects the communication.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a communication system having a transmission line switching function capable of promptly switching a transmission line when an abnormality occurs in the transmission line. Is to provide.

[0006]

In order to achieve the above object, the present invention includes first and second communication devices and first and second transmission lines, wherein the first and second communication devices are A communication system for performing communication through one of the first and second transmission lines, wherein the first communication device communicates with the second communication device through one of the first and second transmission lines. A path information holding unit that holds path information indicating whether or not to perform, the path information that the path information holding unit holds, and the path information holding unit that communicates with the second communication device through the first transmission path. A path information initialization unit that initializes the path information, and when communicating with the second communication device, examines the path information held by the path information holding unit, and checks the second through a transmission path represented by the path information. Communication control to communicate with other communication devices A transmission line monitoring unit that monitors whether a communication device that configures the first transmission line is normal or abnormal; and that the communication device is abnormal as a result of monitoring by the transmission line monitoring unit. A path information change unit that changes the path information held by the path information holding unit to path information indicating that communication with the second communication device is to be performed through the second transmission path. It is characterized by having.

In the communication system having the transmission line switching function according to the present invention, the path information initialization unit communicates the path information held by the path information holding unit with the second communication device via the first transmission line. The communication control unit always sets the second through the first transmission path based on the route information initialized by the route information initialization unit.
Communication with the communication device. The transmission line monitoring unit monitors whether the communication device forming the first transmission line is normal or abnormal, and the path information change unit determines that the communication device is abnormal as a result of monitoring by the transmission line monitoring unit. When it is determined, the route information held by the route information holding unit is changed to the route information indicating that communication with the second communication device is performed through the second transmission path. As a result, the communication control unit communicates with the second communication device via the second transmission path based on the changed route information. Therefore, in the communication system of the present invention, the transmission path to be used can be switched by changing the path information held by the path information holding unit. Can be performed only by directly changing the storage contents of the storage device, and a complicated procedure is not required. Therefore, switching of the transmission path is completed in a very short time.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a main block diagram showing an example of a communication system having a transmission line switching function according to the present invention, and FIG. 2 is an overall block diagram. The communication system 2 having the transmission line switching function according to the present embodiment specifically forms a store system, and includes a server device 4 (a first communication device according to the present invention) including a computer and a computer. 6 that constitutes a POS register including a client (second communication device according to the present invention)
The server device 4 and the client 6 always communicate through the sub-network 8, and communicate with each other through the sub-network 10 when an abnormality occurs.

As shown in FIG. 1, the server device 4 includes a path information definition table 12 (a path information holding section according to the present invention), a communication control section 14, a transmission path switching section 16, and the like. The section 16 includes a path information initialization section 18, a transmission path monitoring section 20, and a path information change section 2.
Contains 2. The route information definition table 12 is configured by, for example, a hard disk,
10, the communication control unit 14 checks the path information held by the path information definition table 12 when communicating with the client 6, and indicates the path information. Client 6 via communication port 24 or communication port 26 through a transmission path
Communicates with

For example, when the server device 4 is started, the route information initialization unit 18 converts the route information stored in the route information definition table 12 into route information indicating that communication with the client 6 is to be performed through the sub-network 8. Initialize. Further, the transmission path monitoring unit 20 is a switching hub device 2 which is a main communication device constituting the sub network 8.
8 (communication device according to the present invention) is monitored through the communication port 24 to determine whether the communication device is abnormal or abnormal as a result of monitoring by the transmission path monitoring unit 20. Is found, the route information held in the route information definition table 12 is
0 is changed to path information indicating that communication with the client 6 is performed.

The subnetwork 8 connected to the communication port 24 of the server device 4 (first transmission line according to the present invention)
2, a switching hub device 28 to be monitored by the transmission path monitoring unit 20, a plurality of switching hub devices 30, 32, 34, 36 connected to a lower layer of the switching hub device 28, and a lower layer. Each client 6 includes a plurality of hub devices 38 connected to the hub device 3.
8 is connected. The switching hub device 30
The switching hub device 32 is provided with a switching hub device 32, and the switching hub device 34 is provided with a switching hub device 36. Therefore, for example, when an abnormality occurs in the switching hub device 32, communication is continued using the switching hub device 32. On the other hand, the subnetwork 10 connected to the communication port 26 of the server device 4 includes a hub device 40, and the hub device 40 and one hub device 38 forming the subnetwork 8 are connected via a router 42. I have.
The sub-network 10 and the router 42 form a second transmission line according to the present invention.

Next, the operation of the communication system 2 having the transmission line switching function configured as described above will be described with reference to the flowchart shown in FIG. The path information initializing unit 18 stores the path information held by the path information definition table 12 when the server device 4 is started, for example.
Initially set to route information indicating that communication with the client 6 is performed through the sub-network 8 (step S
1). For example, if the address of the subnetwork 8 is "10.
1.1 "and the address of the switching hub device 28 is" 10.1.1.251 ", the path information initialized by the path information initializing unit 18 has this address" 10.1.1. " .251 "is included.

When transmitting a communication message to, for example, the client 6A, the communication control unit 14 first refers to the route information held in the route information definition table 12, and adds the address “of the switching hub device 28” to this route information. 1
0.1.1.251 ", the communication message is transmitted to the client 6A through the sub network 8 via the communication port 24. In this case, the communication paths are paths 43, 44, 46, and 48, as indicated by thick lines in FIG.
Becomes

On the other hand, the transmission line monitoring unit 20 monitors via the communication port 24 whether the switching hub device 28 constituting the sub-network 8 is normal or abnormal (step S2). As a result, the switching hub device 28 Is normal (Yes in step S3), the operation is stopped for a certain period of time (step S4), and then step S2
And the switching hub device 28 is monitored again.

On the other hand, if the switching hub device 28 is abnormal (No in step S3), the route information changing unit 22 sends the route information held in the route information definition table 12 to the client through the subnetwork 10. 6 is changed to the route information indicating that communication is performed with the device 6 (step S5). In this case, the path information changing unit 22 determines the address “10.1.1.1.2” of the switching hub device 28 included in the path information held in the path information definition table 12.
51 ”is deleted first, and then the address of the sub-network 10 is, for example,“ 10.1.2 ”and the router 42
Is "10.1.2.254", the path information changing unit 22 determines that the address "10.1.
2.254 ". At this time, the path information changing unit 22 closes the communication port 24 so that communication can be performed more reliably through the communication port 26 (step S6).

As a result of the change of the route information by the route information change unit 22, when the communication control unit 14 tries to send a communication message to the client 6A, the router 42 stores the route information in the route information as information indicating the transmission path to be used. Address "1"
0.1.2.254 ", the sub-network 10 and the router 42 are connected via the communication port 26.
The communication message is sent to the client 6A through the client. The communication paths in this case are paths 52, 54, 56, 58, 46, and 48, as indicated by the thick lines in FIG.
The communication message enters the sub-network 8 via the sub-network 10 and the router 42, and is transmitted to the client 6A via the hub device 38 and the switching hub device 30.
To reach.

As described above, in this embodiment, when a failure occurs in the switching hub device 28 which is a main communication device of the sub-network 8, communication through the sub-network 8 becomes impossible. The route information held in the route information definition table 12 is immediately changed, and the connection is connected to the client 6 through the subnetwork 10 and the router 42, so that the communication can be continued. The change of the route information by the route information changing unit 22 can be performed only by directly changing the storage contents of a storage device such as a hard disk, for example, and a complicated procedure is not required. Complete with Therefore, even if an abnormality occurs in the switching hub device 28, the server device 4 and each client 6 can continue real-time communication.

Although the communication system is a store system in the present embodiment, this is merely an example, and the present invention can be widely applied to other than the store system.
In the present embodiment, when the determination result in step S3 is YES, the transmission line monitoring unit 20 is stopped for a certain period of time. You can change the monitoring time interval. The time to be set may be appropriately set for each communication system to which the present invention is applied, depending on how much delay is allowed before switching the transmission path.

[0019]

As described above, in the communication system having the transmission path switching function according to the present invention, the path information initialization section transmits the path information held by the path information holding section to the second transmission path via the first transmission path. Initially, the communication control unit always sets the first route information based on the route information initialized by the route information initialization unit.
And communicates with the second communication device through the transmission path. The transmission line monitoring unit monitors whether the communication device forming the first transmission line is normal or abnormal, and the path information changing unit determines that the communication device is abnormal as a result of the monitoring by the transmission line monitoring unit. When it is determined, the route information held by the route information holding unit is changed to the route information indicating that communication with the second communication device is performed through the second transmission path. As a result, the communication control unit communicates with the second communication device via the second transmission path based on the changed route information. Therefore, in the communication system of the present invention, the transmission path to be used can be switched by changing the path information held by the path information holding unit. Can be performed only by directly changing the storage contents of the storage device, and no complicated procedure is required. Therefore, the switching of the transmission path is completed in a very short time.

[Brief description of the drawings]

FIG. 1 is a main block diagram showing an example of a communication system having a transmission line switching function according to the present invention.

FIG. 2 is an overall block diagram illustrating an example of a communication system having a transmission line switching function according to the present invention.

FIG. 3 is a flowchart showing an operation of the communication system of FIG. 1;

FIG. 4 is an overall block diagram illustrating an example of a communication system having a transmission line switching function according to the present invention.

[Explanation of symbols]

2. Communication system having transmission line switching function 4.
... server device, 6 ... client, 8 ... subnetwork, 10 ... subnetwork, 12 ... route information definition table, 14 ... communication control unit, 16 ... transmission line switching unit, 18 ... initial information , A transmission line monitoring unit, 22 a path information change unit, 24 a communication port,
26 communication port 28 switching hub device
30, switching hub device, 32, switching hub device, 34, switching hub device, 36, switching hub device, 38, hub device, 40, hub device, 42, router, 43, 44, 46 , 48, 5
2, 54, 56, 58 ... route.

Claims (7)

[Claims] 1. A communication system, comprising: first and second communication devices; and first and second transmission lines, wherein the first and second communication devices communicate through one of the first and second transmission lines. A communication system for performing communication, wherein the first communication device includes: a path information holding unit that holds path information indicating which of the first and second transmission paths performs communication with the second communication device; A path information initialization unit that initializes the path information held by the path information holding unit to the path information indicating that communication with the second communication device is performed through the first transmission path; A second communication device that communicates with the second communication device through a transmission path indicated by the route information when communicating with the second communication device; Communication devices that make up the transmission path are normal A transmission line monitoring unit that monitors whether the communication device is abnormal or abnormal, as a result of monitoring by the transmission line monitoring unit, when it is determined that the communication device is abnormal, the path held by the path information holding unit; A path information changing unit for changing information to path information indicating that communication with the second communication device is performed via the second transmission path; and a communication system having a transmission path switching function. . 2. The communication system according to claim 1, wherein said second transmission path includes a router. 3. The communication system according to claim 1, wherein the first communication device is a server device configured by a computer. 4. The communication system according to claim 3, wherein the second communication device is a client device configured by a computer. 5. The communication system according to claim 1, wherein the first transmission path includes a switching hub device. 6. The communication system according to claim 5, wherein said transmission line monitoring unit monitors said switching hub device as said communication device. 7. The server device is a store server device, the client device is a POS register,
5. The system according to claim 4, wherein the system comprises a store system.
A communication system having the transmission path switching function described in the above.