JPH04326643A - Dial retrial suppression method in plural paths - Google Patents

Abstract

PURPOSE:To relieve a CPU load relating to communication and the line utility rate by suppressing a useless dialing in response to the cause to a failed dialing with respect to the dial retrial suppression method in plural paths in the network system having plural communication paths between an opposite party system for communication. CONSTITUTION:A field 17 in which a fault reason code representing retrial enable/disable is set is provided in information of connection establish reply 16 and when a route through which a call to a destination is available is not in existence in a relay node, a fault reason code representing retrial disable is set in the field 17 to return a reply of connection establishment failure. A caller node or a relay node on its way suppresses a dial retrial via a final relay node responsible for the retrial disable when the failure reason code in the information indicates retrial disable with respect to the reply of connection establishment fault.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a method for suppressing call retries on multiple routes in a network system having multiple communication routes with a communicating party system, which is capable of suppressing wasteful retries when connection establishment fails. Regarding.

With the diversification of networks, it has become possible to realize communication between computer systems or between computer systems and terminal devices through various communication paths including switching networks. In such network systems, there is a need for technology to reduce communication costs.

0003

2. Description of the Related Art In mesh networks and networks with multiple lines, multiple communication paths can be used for communication between host processors, workstations (WS), and the like. When multiple communication paths are available, a host processor or workstation generally makes a call using the one communication path that is considered optimal, and if the connection fails, it tries again using another communication path. attempt to establish a connection.

Conventionally, when there are a plurality of communication paths available for establishing a connection, attempts are made to establish the connection through all the paths until the connection is successfully established. FIG. 6 is an explanatory diagram of the prior art. For example, as shown in FIG. 6(A), there are multiple communication paths 20a, 2 between the local system 10 on the calling side and the other side system 12 on the called destination side.
0b, in the prior art, first an attempt is made to establish a connection using the communication path 20a, and if that fails, an attempt is made to establish a connection using another communication path 20b.

[0005] Similarly, when relay systems 11a to 11c are involved as shown in (b) of FIG. An attempt is made to establish a connection using a communication path that passes through path 13a, relay system 11a, transmission path 13c, relay system 11c, and transmission path 13e, and if that fails, transmission path 13b, relay system 11b, transmission path 13d, relay system 11c, Transmission line 1
The call was retried using the communication route via 3e.

[0006]

[Problem to be Solved by the Invention] In the case shown in (a) of FIG. 6, if the establishment of a connection through the communication path 20a fails due to a problem in the other party's system 12, there is no problem with the communication path 20a. , even if a retry is made using another communication path 20b, the connection establishment similarly fails. That is, if there is a problem with the communication partner itself, there is no point in actually retrying.

Even in the case shown in (b) of FIG. 6, the final relay system 11c that relayed the establishment of the connection
If there is a problem after that, that is, transmission line (line) 13e
If there is a problem between the final relay system 11c, such as the relay system 11c, or the other party's system 12, and the connection fails to be established on the communication route via the relay system 11a, the other relay system 11b Even if a call is retried using the communication path that is passed through, the retry will not be successful and the retry will be wasted.

[0008] The present invention aims to solve the above-mentioned problems, and when there are multiple routes to a communication partner, wasteful call origination is suppressed depending on the cause of call failure, and the CPU load and line usage related to communication are reduced. The purpose is to make it possible to reduce the rate.

[0009]

[Means for Solving the Problems] FIG. 1 is a diagram illustrating the principle of the present invention. In FIG. 1, reference numeral 10 denotes a local system on the side that makes a call to establish a connection; 11a, 11b, and 11c are communication relay systems; 12 is a counterpart system such as a host processor or workstation on the receiving side; 13a to 1;
3e is a transmission path that may include a switched network, 14 is a connection establishment request sent when requesting connection establishment, 15 is a field in which the final relay node number is set, and 16 is whether connection establishment has failed. A connection establishment response returns whether or not the connection was successful, 17 is a field in which a failure reason code is set, and 20a and 20b represent communication routes.

[0010] In the network system to which the present invention is applied, for example, the communication route from the own system 10 to the other party system 12 is a communication route 20a using a transmission path 13a or the like.
The system includes a plurality of communication paths 20b using the transmission path 13b and the like.

When communicating between the own system 10 and the other system 12, a connection is first established to establish a logical connection relationship. The connection is established through the communication path 20a or 2 leading to the other party's system 12.
The other party system 1 sends a connection establishment request 14 via 0b and receives the connection establishment request 14.
2 is realized by returning a connection establishment response 16 indicating that the establishment is normal to the local system 10.

In the present invention, when there is a problem in establishing a connection between the final relay system 11c and the communication partner system 12, the following steps are taken to eliminate unnecessary retries. In the information of the connection establishment response 16, a field 17 is provided in which a failure reason code indicating whether retry is possible or not is set. Final relay system 1
1c, when a call cannot be made to the destination system 12, a failure reason code indicating that retry is not possible is set in the field 17 where the failure reason code is set, and the connection establishment response (failure ) 16 to the relay system 11a.

The relay system 11a receives the connection establishment response 16, and if the failure reason code indicates that retry is not possible, the relay system 11a suppresses the call retry and transfers the connection establishment response 16 to its own system 10. The caller's own system 10 also determines the failure reason code field 17 in the connection establishment response 16, recognizes that it indicates that retry is not possible, and transmits the other transmission path 13b.
, the relay system 11b, the transmission path 13d, etc., even if there is a communication path 20b including the relay system 11b, the transmission path 13d, etc., retrying the call via the final relay system 11c is suppressed.

[0014]

According to the present invention, a unique node number is assigned to, for example, each communicating system (self-side system 10, relay systems 11a to 11c, and partner system 12). Then, a connection establishment request 14 is made for each communication partner.
Decide which node number to add to.

The local system 10 requesting establishment of a connection adds a predetermined node number to the connection establishment request 14 and transmits the connection establishment request 14 using one communication path 20a. When a system that relays connection establishment or a system that accepts a request fails to establish a connection for some reason, it checks whether the node number added to the connection establishment request 14 matches its own node number. If they match, information about the connection establishment failure by the final node, that is, the failure reason code indicating that retry is not possible, is sent to the connection establishment response 16.
Set it in field 17 and reply.

[0016] If the connection establishment response 16 includes information about the connection establishment failure by the final node, the local system 10 that requested the establishment of the connection establishes the connection via a route that goes through another relay system 11b. Avoid retrying.

[0017] Conventionally, if there are multiple routes that can be used to establish a connection, even if there is a failure in the transmission line 13e between the final relay system 11c and the other party's system 12, for example, the connection can be established on all routes. However, with the present invention, unnecessary retries can be avoided.

[0018]

Embodiment FIG. 2 shows a format example of connection establishment request information according to an embodiment of the present invention, and FIG. 3 shows a format example of connection establishment response information according to an embodiment of the present invention.

In this embodiment, the connection is established using, for example, X. 25 protocol. FIG. 2 shows an example of the format of the connection establishment request 14 shown in FIG. 1, and (A) is a part similar to the conventional one, where the destination address, source address, protocol information, etc. are set. The extended part (B) is added to this, and the node number of the final relay system, which is uniquely determined by the system for each communication partner, is set in this extended part.

FIG. 3 shows an example of the format of the connection establishment response 16 shown in FIG. 1, and (A) is the same part as the conventional one. The destination address, source address, etc. are set. In this example, the connection establishment response (
An extended part of B) is provided, and a failure reason code indicating whether retry is possible or not is set.

In the example shown in FIG. 1, the node number added to the extended part of the connection establishment request 14 in communication with the partner system 12 in the local system 10 is 0040.
It is 00. When sending a connection establishment request 14 from the local system 10 through the route of the communication path 20a, the connection establishment request 14 is sent with a node number of 004000 added to the field 15 in which the final relay node number is set.

[0022] The relay system 11a having the node number 002000 relays the connection establishment to the relay system 11c having the node number 004000. The relay system 11c of 004000 is a transmission path (line) to the other party system 12.
Since 13e is unavailable, establishment of the connection is refused. At this time, since the node number added to the connection establishment request 14 is the same as its own node number of 004000, the field 17 in which the failure reason code in the connection establishment response 16 is set contains information indicating that retry is not possible, i.e. Sets information about connection establishment failure by the final node.

[0023] The local system 1 receives the connection establishment response 16 as a rejection response via the relay system 11a.
0 indicates a calling error without retrying using another communication path 20b. FIG. 4 shows a flowchart of a calling system according to one embodiment of the present invention.

When the calling system receives a calling request from the user (user program), the calling system performs the process shown in FIG. 4 (a).
) to (k) are performed. (a) Based on the request received from the user (■), a possible route for making a call to the destination is searched. (b) If there is no route available for making a call, notify the user that the connection establishment has failed.

(c) If there is a possible route for making a call, as shown in Figure 2
Create the conventional part of the connection establishment request shown in (d) Determine whether the own system is the final relay node to the destination. If it is the final relay node, proceed to process (g).

(e) If it is not the final relay node, it is determined whether the extended portion can be transmitted to the final relay node to the destination. If the protocol or device cannot transmit the extended part, proceed to process (g). (f) In other cases, add the extended part of the connection establishment request shown in FIG. 2 to the conventional part.

(g) Make the selected route non-reusable for establishing this connection, and send a connection establishment request. The above is the process when a connection establishment request is received. A connection establishment response is returned in response to this connection establishment request. Upon reception of this connection establishment response, the following processing is performed.

(h) Determine whether the received connection establishment response is a normal response. (i) If the response is normal, notify the user that the establishment is normal. (j) If the response is not normal, determine whether the connection establishment response has the extended part shown in FIG. 3 and whether a reason code indicating that retry is not possible is set therein. If a reason code that does not allow retry is set, try to establish a connection using another route that can be called by re-executing steps after ①.

(k) If a reason code indicating that retry is not possible is set, the user is notified of establishment failure. Figure 5 shows
1 shows a flowchart of a relay system (relay system 11a to relay system 11c shown in FIG. 1, etc.) according to an embodiment of the present invention.

[0030] When the relay system receives a connection establishment request from a transmission line (line) or a connection establishment response thereto, the relay system performs the steps (a) to (l) shown in FIG.
Process. (a) Acceptance of a connection establishment request from the transmission path. Based on (2), it is determined whether the connection establishment request has the extended part shown in FIG. 2. If there is no extended part, proceed to process (c).

(b) If there is an extension, it is determined whether the local system is the final relay node to the destination. If it is the final relay node, proceed to process (f). (c) If it is not the final relay node, search for a possible route to the destination. (d) If there is no route that can be called, the requester is notified of the failure to establish the connection in the conventional format.

(e) The selected route cannot be reused for establishing this connection, and the connection establishment request is relayed through that route. (f) If the local system is the final relay node, search for a possible route to the destination. If there is no route that can be called, proceed to process (h).

(g) If there is a route that can be called, delete the extended part in the connection establishment request shown in FIG.
Change to the conventional format and move on to process (e). (h) If there is no route that can be called, add an extended part of the failure reason code indicating that retry is not possible to the connection establishment response.

(i) Send the connection establishment response (failure) with the extension part shown in FIG. The above is the process when a connection establishment request is received. In response to the relay of this connection establishment request, the following processing is performed upon reception of the connection establishment response returned from the relay destination (destination).

(j) Determine whether the received connection establishment response is a normal response. (k) If the response is normal, a connection establishment response indicating that establishment was normal is transmitted to the relay or calling source. (l) If the response is not normal, it is determined whether the connection establishment response has the extended part shown in FIG. 3 and a reason code indicating that retry is not possible is set therein. If a reason code that does not allow retry is set, try to establish a connection using another route that can be called by re-executing steps after ①. If a reason code that does not allow retry is set, proceed to process (i),
Sends a connection establishment response that rejects establishment.

[0036]

[Effect of the invention] As explained above, according to the present invention,
It is possible to suppress wasteful retry operations for establishing a connection, and has the following effects. In particular, the larger the network system, the greater the following effects.

[0037] ■ It is possible to reduce the CPU load on the calling source and the relay system, as well as reduce the line usage rate. ■ When systems are connected via a switched network, unnecessary charges are not incurred and communication costs can be reduced.

■ The cause of the failure can be notified to the user of the user program, and the scope of the problem can be narrowed down.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention.

FIG. 2 is a diagram showing an example format of connection establishment request information according to an embodiment of the present invention.

FIG. 3 is a diagram showing an example format of connection establishment response information according to an embodiment of the present invention.

FIG. 4 is a flowchart of a calling system according to one embodiment of the present invention.

FIG. 5 is a flowchart of a relay system according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram of the prior art.

[Explanation of symbols]

10 Local systems 11a to 11c Relay system 12 Opposite systems 13a to 13e Transmission path 14 Connection establishment request 15 Field 16 in which the final relay node number is set Connection establishment response 17 Fields 20a and 20b in which failure reason code is set Communication route

Claims (1)

[Claims] Claim 1. A calling retry prevention method in a network system having a plurality of communication paths (20a, 20b) with a communicating partner system, wherein a retry possible/retry request is included in information of a connection establishment response (16). Field (17) where a failure reason code indicating “Not possible” is set.
If there is no possible route to the destination, the relay node sets a failure reason code indicating that retry is not possible in the field (17), returns a connection establishment failure response, and makes the call. At the source node or intermediate relay node, in response to a connection establishment failure response, if the failure reason code in the information indicates that retry is not possible,
A method for suppressing call retries on multiple routes, characterized by suppressing call retries via the final relay node that caused the problem.