JP2003348134A - Communication path selecting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication path selecting system for enhancing the flexible adaptation of a communication path to establish connection. <P>SOLUTION: The communication path selecting system comprises a host computer 1: terminals 41, 42; and a plurality of networks 31 to 37, and a plurality of the networks 31 to 37 are interposed between the host computer 1 and the terminals 41, 42 to form a plurality of paths in a network shape. The host computer 1 prepares a plurality of connection forms at establishment of connections between the host computer 1 and the terminals 41, 42 and has path information corresponding to the terminals 41, 42, the path information storing a plurality of communication resources to be used by each opposite IP address or a network address of an opposite party for connection establishment. Accordingly, loads of the communication resources are distributed and when the priority of reliable communication is taken into account, the system can earlier select a network with higher reliability. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication path selection system, and more particularly to a communication path selection system for appropriately selecting and establishing a communication path at the time of establishing a connection.

[0002]

2. Description of the Related Art Conventionally, a communication path selection system is applied, for example, as a communication path selection system when a connection is established. Generally, when establishing a connection of a communication path, the procedure of a communication processing device for issuing a connection establishment request to a terminal having a specific IP (Internet Protocol) address is fixed.

For example, an application does not perform dynamic path information exchange between a communication processing device and a host computer, but operates on a TCP (T) operating on a host computer connected to a plurality of networks by a plurality of communication processing devices.
An example is a case where a (ransmission Control Protocol) connection is used. In this example, when establishing a connection to a terminal connected to the host computer through a plurality of communication paths, a connection establishment request is sent to a terminal having a specific IP address even if the own IP address is not explicitly specified. The procedure of the outgoing communication processing device is unique and fixed.

Example 1 of the prior application similar to the present invention in the technical field
Japanese Patent Application Laid-Open No. 2001-339431 discloses a “communication system, relay device, end system and communication system”.
In Inventive Invention Example 1, a connection is established between a communication source end system and a communication destination end system via a plurality of relay devices to communicate data. At this time,
Even if connection establishment fails due to an error in the relay device on the way, a negative acknowledgment packet is returned to the communication source end system from the point of occurrence of this error to recognize a path failure. If a path failure is recognized, a connection is established via another relay device without notifying the application, and a connection to the destination end system that has avoided the failure path in a short time is established, and data communication (business ) Is disclosed with respect to techniques that can be initiated.

[0005]

However, the conventional example has several problems. A first problem of the general conventional example is that in such a system, if a network failure occurs in one path, the application fails to establish a connection even though the entire network can be connected. There are cases.

A second problem of the general prior art is that, in order to establish a connection through a detour path, the communication processing apparatus is set to a failure state, or path information is dynamically rewritten.
There is no other way than to explicitly specify the own IP address in the application and establish the connection again.

[0007] In the above-mentioned prior invention example 1, the first and second general problems listed above are that the detour route selection performed by the relay device is performed by the communication processing device connected to the host computer. The solution is achieved by selecting. In the present invention, while solving each of these problems,
In addition, by providing a plurality of communication processing device selection logics, it becomes possible to distribute the load of the network and transmit the data from a more reliable communication device, which is impossible in the first example of the present invention. By managing the error number of the connection establishment failure, useless alternate transmission processing is not performed, and the speed and reliability of the processing are further improved.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a communication route selection system with improved flexibility in establishing a communication route connection.

[0009]

In order to achieve the above object, a communication path selection system according to the present invention is a communication path selection system including a host computer, a terminal device, and a plurality of networks. A plurality of paths are formed in a net-like manner with a plurality of networks interposed between the apparatus and the apparatus, a plurality of connection forms are established when a connection is established between the host computer and the terminal apparatus, and path information corresponding to the terminal apparatus is stored in the host. The computer is provided, and the path information stores a plurality of communication resources to be used for each connection destination IP address or connection destination network address.

Further, the host computer further includes a plurality of communication processing devices connected to the terminal device via a network to form a predetermined communication path, and controls an operation of establishing a connection with the terminal device. It is preferable to further have an application for performing the operation.

Further, the path information includes information on which communication processing device should be transmitted next from among a plurality of communication resources when a communication path is established, and dynamic path information between the communication processing device and the host computer is transmitted. Even when the exchange is not performed, it is preferable that the connection can be established by the route detour without making the application aware of the network failure.

[0012] Information on which communication processing device should be transmitted next is initialized when connection is successfully established.
It is preferable to set communication resource selection logic to enable load distribution of the communication resource, to eliminate connection operation repeatedly executed by an error number of connection establishment failure, and to avoid useless alternate call processing.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a communication route selection system according to the present invention will be described in detail with reference to the accompanying drawings. Referring to FIGS. 1 to 4, there is shown one embodiment of a communication path selection system of the present invention.

(Description of the main points of the invention) In FIG. 1, a plurality of networks (31, 32, 33, 34, 45) are connected by a plurality of communication processing devices (21, 22, 23, 24, 25).
Operating on the host computer 1 connected to
There is an application 12 using a CP (Transmission Control Protocol) connection (hereinafter referred to as a connection).

The host computer 1 has a terminal (device) 4
1 and a plurality of routes (51, 52, 5
Assume that connection is possible in 3). Under this condition, in the present embodiment, when one path is in a failure state, the application 12 can establish a connection through the detour path without being aware of the failure.

When the host computer 1 has a plurality of communication processing devices (21, 22, 23, 24, 25) and does not perform dynamic exchange of routing information between the communication processing device and the host computer (when the host computer 1 is a RIP) When the host computer 1 establishes a TCP connection, any of the communication processing devices (21, 22, 23, 24,
25), even if the application 12 that establishes the connection does not explicitly specify its own IP address, the communication processing device (21, 22, 23, 24,
25) I of the connection establishment partner until the failure of 25) is detected
Fixed by P address.

The above-mentioned "case where dynamic exchange of routing information is not performed" means that the host computer 1 generates a packet broadcast by the router and the server every 60 s (RIP (Routing Information Protocol)).
OSPF (Open Shortest Path Fast), a network layer protocol for routing and multicasting
), Etc., when dynamic routing is not performed.

For example, when one network fails, the application 12 may fail to establish a connection even though the entire network is in a connectable state. In such a system, by providing a plurality of communication resources (communication processing devices, network interface cards, etc.) information in the static device selection information for each IP address of the connection establishment partner, the application 12
Can establish a connection by bypassing the failed network via another communication processing device (21, 22, 23, 24, 25) without being aware of a network failure. By enabling a plurality of logics to be set when selecting a communication resource, it is possible to distribute the load of the resource.

Since it is possible to specify whether or not to make a detour by using error information, useless detour is performed in the event of a failure (such as when there is a problem with a partner terminal that establishes a connection) that always fails even if a call is made on the detour route. Without calling processing,
Application 12 promptly fails connection establishment
Can be notified.

FIG. 1 shows a communication system to which an embodiment of a communication route selection system according to the present invention is applied. FIG. 2 shows a network control middleware 11 constituting the host computer 1 in FIG.
3 is a block diagram showing a more detailed configuration example of FIG. The communication system applied to the present embodiment includes a host computer 1 having a network control middleware 11 and an application 12, communication processing devices 21, 22, 23, and 2.
4, 25, networks 31, 32, 33, 34, 3
5, 36, 37 and terminals (devices) 41, 42. Note that the three types of broken lines in FIG. 1 clearly show examples of the connected paths 51, 52, and 53. Also, the network control middleware 11 is configured as shown in FIG.
As shown in the figure, the route information storage unit 61 stores, for example, route information 71 for the IP address A of the terminal (device) 41 and route information 72 for the IP address B of the terminal 42. , Shall be provided.

In this embodiment, as described above, the host computer 1 and the plurality of communication processing devices 21, 22, 23, 24, 25 connected to the host computer 1,
Networks 31, 32, 33, 34, 35, 3 connected to the communication processing devices 21, 22, 23, 24, 25
6, 37, an application 12 operating on the host computer 1, and a network control middleware 11 for controlling establishment of TCP / IP connections, transmission and reception of data, and release of connections.

The network control middleware 11 receives a connection establishment request from the application 12, selects a communication processing device (21, 22, 23, 24, 25) based on a partner IP address for establishing a connection, and selects the selected communication process. Devices (21, 22, 23, 2
4, 25). The communication processing device (21, 22, 23, 24, 25) establishes a connection to the specified partner IP address, and notifies the network control middleware 11 whether or not the connection has been successfully established.

The network control middleware 11 notifies the application 12 of the connection establishment information notified from the communication processing devices (21, 22, 23, 24, 25). Note that between the network control middleware 11 and the communication processing devices (21, 22, 23, 24, 25), RIP (Routing Information Protocol) or OSPF
There is no dynamic route information exchange such as (Open Shortest Path Fast).

In the route information storage unit 61 of the network control middleware 11 shown in FIG. 2, which communication processing device (21, 22, 23, 24, 25) is provided for each destination IP address and network address transmitted from the host. It has path information (71, 72) for selecting. The application 12 does not explicitly specify its own IP address when establishing a connection.

The route information of the network control middleware 11 includes the IP address of the connection establishment partner,
Alternatively, a plurality of communication resources to be used are stored for each destination network address. Route information (71, 7
2) has information on which communication processing device (21, 22, 23, 24, 25) should be transmitted next among a plurality of resources.

The communication processing devices (21, 22, 23, 24, 25) to be transmitted next to the route information (71, 72) are initialized when the connection is successfully established. At the time of this initialization, a method of always keeping the priority of each device constant, the priority of the communication processing device (21, 22, 23, 24, 25) connected to the most reliable network that has finally transmitted successfully Any one of the three device selection logics can be used for each of the route information, such as a method of increasing the order and a method of uniformly transmitting the signals from all the communication processing devices (21, 22, 23, 24, 25) to perform load distribution. Registered in. Route information (71, 7
2), the communication processing device (2
1, 22, 23, 24, and 25), the error numbers that do not perform the roundabout transmission process are registered.

(Operation Example) In the route information section of the network control middleware, a communication processing device (21, 22,
23, 24, 25) for each route information.
1, 22, 23, 24, 25) are registered in advance. The application 12 issues a connection establishment request to the network control middleware 11 in order to establish a connection from the host computer to the terminal (step A1 in FIG. 3).

The network control middleware 11 searches for path information as to which communication resource should make a connection establishment request (step A2). In order to establish a connection from the selected communication processing device (21, 22, 23, 24, 25), the network control middleware 11 communicates with the communication processing device (21, 22, 23,
24, 25) to establish a connection with the terminal (step A3).

When a network failure occurs, the communication processing device (21, 22, 23, 24, 2
5) notifies the network control middleware 11 of the network failure and the connection establishment failure (step A4). The network control middleware 11 notified of the failure of the connection establishment, the communication processing device (21, 2)
Based on the error number notified from (2, 23, 24, 25), it is determined whether or not to make a bypass call (step A5). At this time, in the case of an error number that does not perform the roundabout transmission, the failure of the transmission is notified to the application 12 (step A7).

In the case of other errors, it is checked whether connection establishment has failed in all communication resources,
If the connection establishment has failed for all communication resources, the application 12 is notified of the failure of the transmission (step A6).

If there is a communication resource for which the detour transmission process has not been performed yet, the communication processing device (21, 22, 23, 24,
25) is selected (step A2). Next, a request for establishing a connection to the terminal (device) 41 is made to the selected communication processing device (21, 22, 23, 24, 25) (step A3). The sequence of steps A2 to A7 is repeated until connection establishment fails on all routes or until connection establishment succeeds. Communication processing device (2
1, 22, 23, 24, and 25), the network control middleware 11 notifies the communication processing device (21, 2,
2, 23, 24, 25) (Step A)
8).

Communication processing devices (21, 22, 23, 24,
25) Initialization is performed as follows according to the selection logic. When a method is set so that the priority of selection of the communication processing device (21, 22, 23, 24, 25) is always constant, the communication processing device (21, 22, 23,.
24, 25) are returned to the initial values. Communication processing device (21, 2
(2, 23, 24, 25) The priority of selection is higher in the priority of the communication processing device (21, 22, 23, 24, 25) connected to the network with the highest reliability in which the transmission was successful last. When the logic setting to be performed is set, the communication processing device (21, 22, 23, 24, 2
5), the communication processing device (21, 2)
2, 23, 24, 25).

Communication processing devices (21, 22, 23, 24,
25) If the priority of selection is set so that all communication processing devices (21, 22, 23, 24, 25) transmit the same evenly because of load distribution, the communication resource of the last successfully transmitted communication resource The communication resource with the next highest priority is set. The connection establishment is notified to the application 12 (step A9).

Next, the operation will be described with reference to a specific example. FIG.
The system shown in FIG. 1 shows a state where a failure has occurred in the network 31. The application 12 of the host computer 1 shown in FIG. 4 issues a connection establishment request to the terminal (device) 41 (step A1).

When the network control middleware 11 receives a connection establishment request from the application 12 and sends the request to the IP address A of the terminal (device) 41, the communication control device (21, 22, 23, 24, 2
Whether to notify a connection establishment request to 5) is determined from the route information 71. It is assumed that the route information 71 points to the communication processing device 21 as the communication processing device (21, 22, 23, 24, 25) to be selected next.

Based on the route information, the network control middleware 11 determines the communication processing device 21 as a device for notifying the connection establishment request, and issues a connection establishment request to the determined communication processing device 21 (steps A2 and A3). . Upon receiving the connection establishment request from the network control middleware 11, the communication processing device 21 issues a connection establishment request to the terminal (device) 41 via the network 31. When a failure occurs in the network 31 and the connection to the terminal (device) 41 cannot be established, the connection establishment request of the communication processing device 21 to the terminal (device) 41 fails. The communication processing device 21 notified of the connection establishment failure transmits the connection establishment failure and the error number information to the network control middleware 1.
1 is notified (step A4).

The network control middleware 11 notified of the connection establishment failure determines from the error number information whether or not to make a bypass call (step A5). Network control middleware 11 that should be bypassed
Since the connection information has not failed in all the alternative routes from the route information 71, the connection request is issued from the next alternative route.

The network control middleware 11 determines the communication processing device that notifies the connection establishment request to the communication processing device 22, and issues a connection establishment request to the communication processing device 22 (steps A2 and A3). Upon receiving the connection establishment request from the network control middleware 11, the communication processing device 21 issues a connection establishment request to the terminal (device) 41 via the network 32.

If the connection has been successfully established, the communication processing device 22 notifies the network control middleware 11 of the successful connection establishment. The network control middleware 11 notified of the successful connection establishment notifies the application 12 of the successful connection establishment. The network control middleware 11 stores the route information 7
The pointer to the communication resource to be selected next to 1 is sent to the communication processing device 21 when the communication resource selection logic is of the fixed priority type, to the communication processing device 23 when the load distribution type is the
When the communication reliability priority type is set, it is set in the communication processing device 22.

With the above operation, when the network 31 is in the failure state, the terminal (device) 4
1 can establish a connection. Terminal (device) 4 again
When a connection establishment request is made to the first communication processing device, if the communication resource selection logic is of a load distribution type, the communication processing device 23 is selected as the first communication processing device to transmit, and the load of the communication resource is distributed. Can be done.

In the case of the fixed priority type communication resource selection logic, the communication processing device 21 is selected as the first communication processing device to transmit, and the load of the communication resource can be fixed. In the case of the communication reliability priority type, the communication processing device 22 is selected as the first communication processing device to transmit, and a network with higher reliability can be selected first.

The above embodiment is an example of a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

[0043]

As is apparent from the above description, the communication path selection system of the present invention has a plurality of networks interposed between a host computer and a terminal device to form a plurality of paths. A plurality of connection forms are established when a connection is established between the terminal and the terminal device. The host computer has path information corresponding to the terminal device, and the path information should be used for each destination IP address or destination network address of the connection establishment. A plurality of communication resources are stored.

As described above, by providing a plurality of pieces of communication resource information to the static route information of the host computer, the network under the communication resources does not become aware of the network failure when the network under the communication resource fails.
A connection can be established by a detour route.

Further, by making it possible to select a plurality of communication resource selection logics under one path information, load distribution of communication resources can be performed. Since the alternate call can be avoided by the error code returned by the communication processing device, it is possible to promptly notify the application of the failure of the connection establishment without performing the unnecessary alternate call.

[Brief description of the drawings]

FIG. 1 is a diagram showing a communication system to which an embodiment of a communication route selection system according to the present invention is applied.

FIG. 2 is a block diagram illustrating a more detailed configuration example of network control middleware configuring a host computer.

FIG. 3 is a flowchart illustrating an example of an operation procedure.

FIG. 4 is a diagram for explaining an example of a processing procedure when a failure occurs in establishing a connection;

[Explanation of symbols]

1 host computer 11 network control middleware 12 applications 21, 22, 23, 24, 25 communication processing devices 31, 32, 33, 34, 35, 36, 37 networks 41, 42 terminals (devices) 51, 52, 53 route 61 route Information storage unit 71 Route information (for IP address A of terminal 41) Route information 72 (for IP address B of terminal 42)

Claims (7)

[Claims] 1. A communication route selection system comprising a host computer, a terminal device, and a plurality of networks, wherein the plurality of networks are interposed between the host computer and the terminal device, and a plurality of routes are formed in a net shape. A plurality of connection forms are established for establishing a connection between the host computer and the terminal device. The host computer includes path information corresponding to the terminal device. A communication path selection system, wherein a plurality of communication resources to be used are stored for each address or partner network address. 2. The communication path according to claim 1, wherein the host computer further includes a plurality of communication processing devices connected to the terminal device via the network to form a predetermined communication path. Selection system. 3. The communication path selection system according to claim 1, wherein the host computer further has an application for controlling an operation of establishing a connection with the terminal device. 4. The communication apparatus according to claim 1, wherein the path information includes information on which communication processing apparatus should be next transmitted from a plurality of communication resources when a communication path is established, and a dynamic communication between the communication processing apparatus and the host computer. 4. The communication path selection system according to claim 2, wherein even when the path information is not exchanged, a connection can be established by detouring the path without making the application aware of a network failure. 5. The communication path selection system according to claim 2, wherein the information as to which communication processing device should be transmitted next is initialized when the connection is successfully established. 6. The communication path selection system according to claim 1, wherein the communication resource selection logic is set to enable load distribution of the communication resources. 7. The method according to claim 3, wherein a connection operation repeatedly executed according to the error number of the connection establishment failure is eliminated, so that useless roundabout transmission processing can be avoided. Communication route selection system.