JPH01255345A - Automatic line fault recovery system - Google Patents

Abstract

PURPOSE:To enable a data transmission with high reliability without allowing a terminal or host to be conscious of a line fault by providing a function to automatically recover the line fault between relay systems. CONSTITUTION:When the line fault is generated while a relay system K2 receiving the transmission request of data from a processing program 2-1 of a terminal 1 through a communication line beta1 transmits the data through a communication line gamma1 to a relay system K1, the relay system K2 issues a session establishing request for establishing the communication line gamma1 to the relay system K1, and the establishment of the session is executed. The relay system K2 re-sends the data to be held without being released to the relay system K1. Thus, without allowing a terminal 2 or a host 3 to be conscious of the line fault the recovery is automatically executed by the relay system 1, and the data transmission having the high reliability can be executed.

Description

[Detailed Description of the Invention] [Summary] Regarding an automatic line failure recovery method for recovering from a line failure during mutual communication via a line, a relay system is connected to each terminal or host, and a relay system is connected between these relay systems. The purpose is to provide a function to automatically recover from line failures, and to perform data transmission with high reliability without the terminals or hosts being aware of line failures. Relay systems are provided that are connected via communication channels, these relay systems are connected to each other via communication channels, and relay systems that receive transmission requests from the terminals or hosts via the communication channels fall under this category. transmits data to the relay system via the communication path and holds this transmission data, and releases the held transmission data when a delivery confirmation signal is returned from the relay system at the destination;
The configuration is such that when a line fault is detected, the held transmission data is retransmitted and the line fault is automatically recovered between the relay systems.

[Industrial application field]

The present invention relates to a line fault automatic recovery system for recovering from a line fault during mutual communication via a line.

[Prior art and problems to be solved by the invention] Conventionally, as shown in FIG. For example, after the terminal 'r re-established the communication channel, the data was retransmitted. In this case, the job being executed may end abnormally, and the processing program for executing the job may have to be restarted and then restarted. In this way, if the line quality is poor, or if the line is used for a type of business that requires high line quality (for example, banking), there will be a loss of time in restarting the job, and the transmission information center itself will suffer. In addition to reducing reliability,
There was a problem in that terminal T and host M had to have a line recovery function.

The present invention connects relay systems to terminals or hosts, and provides a function to automatically recover line failures between these relay systems, thereby improving reliability without the terminals or hosts being aware of line failures. The purpose is to perform high data transmission.

[Means to solve problems]

FIG. 1 shows a block diagram of the principle during normal operation, and FIG. 2 shows a block diagram of the principle when a line failure occurs.

1 and 2, a relay system 1 connects to a terminal 2 or a host 3 via a communication path, and also connects to another relay system 1 via a communication path, and has a relay function. The terminal 2 and the host 3 are the entities that communicate with each other.

[Effect]

In the present invention, during normal operation shown in FIG. 1, data (
Relay system (K2) 1, which has received the transmission request for serial number 1) (■ in Figure 1), transmits the data (serial number 1) to relay system (Kl) via communication path γ1 (■ in Figure 1). Retain data and deliver li1! If you receive a positive response (
The held data is released as shown in (■) in Figure 1. Relay system (Kl) 1 receives the transmitted data (serial number l)
Processing program 3-1 of host 3 via communication path α
(■ in Figure 1). From now on, as shown in Figure 1 ■,
Data is sent and received.

Next, in FIG. 2, the processing program 2-1 of terminal l
Relay system (K2) 1 receives a request to send data (serial number 9) via communication path β1, and transmits the data (serial number 9).
If a line failure occurs during transmission of the line to the relay system (Kl) via the communication path γ (Fig. 2 ■), the occurrence of this line failure will be reported to the relay system (K2) (Kl) 1 will be notified. Correspondingly, the relay system (K2) 1 is configured as a relay system (K2).
l) In order to establish the communication path γ, a session establishment request is issued to 1 to establish the session (Fig. 2
), the relay system (K2) 1 retransmits the held data (serial number 9) to the relay system (Kl) 1 without releasing it (Fig. 2). Thereafter, data (serial number 10) and the like are sequentially transmitted from the relay system (K2) 1 to the relay system (Kl) 1 via the communication path T+.

Therefore, by connecting the relay system 1 to the terminals 2 or hosts 3 that wish to communicate with each other via a communication path, and providing these relay systems 1 with a relay function and a data recovery function against line failure, the terminals 2 or host 3 without making them aware of the line failure.
Automatic recovery is possible.

〔Example〕

Next, the configuration and operation of one embodiment of the present invention will be explained in detail using FIGS. 3 to 6.

In FIG. 3, P C (Path Control
s communication path management unit) manages logical communication paths.

PATH(+), PATH(β+),
P ATH (T1) is a communication path.

SC (Session Control) maintains and manages the connection relationship with the communication partner (maximum data length, type of partner device, etc.) for each communication path, and supports efficient data transfer. It is something to do. SCM (1), SCM (β,), SCM
(TI) is the communication path PATH(+), PATH(β
+) and PATH (TI), respectively, to manage connection relationships for the corresponding communication paths.

RC (Route Control, relay control unit)
It maintains the relay connection relationship. ROM (β1
, γ, ) manages the relay connection relationship between the SCM (β1) and the SCM (TI). The RC creates the RcM (β1, TI), etc. in cooperation with the RTM.

The RTM (relay table management unit) manages the relay table as shown in FIG.

RT (relay table) is a relay table that describes connection relationships of communication channels as shown in FIG.

Next, the communication path β1 in the relay system (K2) in Figure 1
Establishment of a communication path between and communication path T will be explained.

■ The SCM (β1) notifies the RC of a session establishment request from the communication path β1 (Fig. 3 ■), which is transmitted from the processing program 2-1 of the terminal 2 via the communication path β1. Relay system (K2) that received a request for data transfer
This means that SCM 1 (β1) notifies RC of a session establishment request from communication path β.

■ I? C makes an inquiry to RTM about a communication path that can be connected to communication path β1 (FIG. 3).

■ RTM notifies that bears (β1, γ,) are available (Fig. 3 ■). This is done by referring to the relay table in Fig. 6 (a) in which RTM is RT. Communication path β1
This means finding a communication path γ1 that can be connected to and notifying the RC of these as bare (β+,'r+).

■ RC creates RCM (β1, T1) (Figure 3 ■).

■ rlcM (β1, γ,) notifies SCM (TI) of a session establishment request. As a result, the communication path β in FIG.
Establishment of a communication path γ1 for connection to is performed. Similarly, in the relay system (K1), the communication path α1 is further established. As a result, logical communication paths (communication path β1, communication path T1, communication path α) are established between the processing program 2-1 of the terminal 2 and the processing program 3-1 of the host 3.
1) is established, and mutual communication becomes possible.

Next, with reference to FIG. 4, the data transmission and reception operations in the relay system (K2) (2) during normal operation will be described in detail.

(1) The data received from the processing program 2-1 of the terminal 2 through the three paths β1 are sequentially enqueued as data 1, 2.3 into the reception queue β (4th
Figure (a)).

(2) The enqueued data is sequentially transmitted to the communication path γ1, which is the bare communication path β1, in a manner to be copied to the transmission queue 1). The transmitted data is dequeued (Figure 4 (b)).

(3) A transmission confirmation is received from the communication path T1, and in response to this, the corresponding data 1.2.3, etc. are dequeued (released) from the reception queue β1 (FIG. 4 (c)).

Through the above procedure, the data 1, 2, 3, etc. received by the relay system (K2) 1 via the communication path β are transmitted to the relay system (K1) 1 via the communication path γ1. Then, it is transmitted from this relay system (Kl) 1 to the processing program 3-1 of the host 3 via the communication path α1.

Next, using FIG. 5, a data recovery mechanism when a line failure occurs will be explained in detail.

(1) A line failure occurs in the communication path γ, and this fact is notified to the relay system (K2) 1 (Fig. 5 (a) ■). This means that the relay system (K2) 1 As shown in (b), the data 12 etc. queued in the transmission queue γ are transferred to the relay system (Kl) 1 via the communication path γ.
For some reason, when sending messages sequentially,
1la has been generated and the relay system (K2) 1 and the relay system (Kl) 1 have been notified of this fact.

In this state, since the delivery confirmation has not been notified to the relay system (K2) 1 from the communication path γ, the data remains enqueued in the reception queue β.

(2) A seciling establishment request for recovery is issued to the RC for the communication path TI. The RC notifies the SC of this request (Fig. 5 (b) ■).

(3) The SC notifies the RC of session establishment completion.

(4) The data enqueued in the reception queue β1 is enqueued again in a manner such that it is copied to the transmission queue T1, and is transmitted to the communication path γ.

Through the above steps, a line failure occurs on the communication path T.
When the relay system (K2) 1 is notified of this, the data 3 and the like held in the reception queue β are re-enqueued into the transmission queue γ- and are automatically retransmitted, so to speak. Therefore, the processing program 2-
1 or the processing program 3-1 of the host 3, the processing program 3-1 of the relay system (K
2) Data recovery by retransmission will be automatically executed by the data recovery mechanism of 1 and the relay system (Kl) 1.

FIG. 6(A) shows the relay table in the relay system (k2), and FIG. 6(B) shows the relay table in the relay system (kl). This means that, for example, the communication path β1 and the communication path γ1 described in the communication path 1 and communication path 2 columns can be connected as a pair.

(Effects of the Invention) As explained above, according to the present invention, the relay system 1 is connected to the terminals 2 or hosts 3 that are to communicate with each other via a communication path, and these relay systems 1 have a relay function. Since the configuration has a data recovery function for line failures, recovery is automatically performed by the relay system 1 without the terminal 2 or host 3 being aware of the line failure. Alternatively, the processing program on the host 3 does not need to have a recovery function, and it also avoids the loss of reliability due to line failures and restarting the processing program, and has high reliability. A data transmission system can be realized.

[Brief explanation of the drawing]

Figures 1 and 2 are block diagrams of the principles of the present invention, Figure 3 is a configuration diagram of one embodiment of the present invention, Figures 4 and 5 are explanatory diagrams of data transmission and reception operations, and Figure 6 is an example of a relay table. , FIG. 7 shows an explanatory diagram of the prior art. In the figure, 1 is a relay system, 2 is a terminal, 2-1.3-1 is a processing program, 3 is a host, α5, β7, T are communication paths, PC is a communication path management unit, SC is a session management unit, R.C.
represents a relay control unit, RTM represents a relay table management unit, and RT represents a control table. Line PH diagram Noriichi gammays
Encyclopedia A (Praise of the Sun and Moon) Ogata Tora Irihon Yoman ni Zumo 3
Rotator sending i! Iblind Seal b (Saniyari Haro (When the first stop is done, Fufu゛〈)) 5 4 Figure 1? Tsui table (Ni 2 of 4). (A) Middle seam table (KlOtS joint (Ron relay table f1) Bird 6 Figure

Claims (1)

[Claims] In a line fault automatic recovery system for recovering from a line fault when communicating with each other via the line, terminals (2) or hosts (3) attempting to communicate with each other
) are provided with respective relay systems (1) connected to each other via a communication path, and these relay systems (1) are connected to each other via a communication path, and communication from the terminal (2) or host (3) is performed. A relay system (1) that receives a transmission request via a communication channel transmits data to the corresponding other relay system (1) via a communication channel, holds this transmitted data, and sends the data to the destination relay system (1). ), the held transmission data is released when a delivery confirmation signal is returned from A line fault automatic recovery method characterized by being configured to automatically recover from a fault.