JPH04278751A - System controlling communication - Google Patents

Abstract

PURPOSE:To smoothly continue data communication by fetching a same data from another normal transmission line in the plural transmission lines when fault occurs in the transmission line during communication so as to pick-up and reproduce it by means of a reception control means connected to the terminal of the transmission party of transmission data. CONSTITUTION:Transmission control means 14 select the plural transmission lines from the transmission lines 121-123 in accordance with the importance degree of transmission data and transmit transmission data in parallel to them. The reception control means 15 of a line containing devices 131 and 132 which are confronting through the transmission lines 121-123 pick-up and reproduce transmission data from data received through the plural selected transmission lines. That is, the control means 15 can pick-up and reproduce transmission data from data received through another normal transmission line even if fault occurs in any of the transmission lines used for exchanging data. Thus, there is no need to newly process communication recovery in accordance with fault occurrence. The control means 15 take data which is received at first in data of the transmission line even if a fluctuation occurs in the state of the transmission line.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control system for transmitting and receiving data via a predetermined transmission path in a line accommodation device that provides an interface between a terminal device and a transmission path.

0002

[Background Art] In recent years, network systems (communication networks) consisting of terminal equipment, transmission paths, and line accommodation equipment that interfaces between these have become more and more popular due to the diversification of transmitted information and the spread of terminal equipment. As the area becomes wider, there is a need for faster transmission speeds and higher reliability.

FIG. 5 is a diagram showing an example of the configuration of a conventional network system. In the figure, line accommodation device 51a
, 51b, 51c, 51d, and 51e have terminal devices 52a, 52b, 52c, and 52d, respectively.
, 52e are connected. Between each line accommodation device,
Transmission lines 53ab, 53ad, 53ae, 53bc, 53
They are interconnected via be, 53cd, 53ce, and 53de. Here, the two suffixes added to the reference number 53 of each transmission line correspond to the suffixes "a to e" of the reference number 51 of the line accommodation devices disposed at both ends of the transmission line. A detour transmission path 54 is provided between the line accommodation devices 51a and 51b in place of the transmission path 53ab.

[0004] In a network system having such a configuration, the transmission path used for data transfer between each line accommodation device is determined based on routing information preset in the sending side line accommodation device. The line accommodation device 51a uses the transmission path 53ab when transmitting data to the line accommodation device 51b, and uses the detour transmission path 54 as an alternative transmission path when a failure occurs in that transmission path. In addition, line accommodation devices 51a and 51c
For mutual data transfer, since there is no transmission path that directly connects these line accommodation devices, the line accommodation device 51b relays and transfers the data received via the transmission path 53ab or detour transmission path 54 to the transmission path 53bc. This is achieved by

[0005]

By the way, in a network system having such a conventional configuration, for example, when a failure occurs in the transmission path 53ab while transmitting data to the line accommodation device 51b, the line accommodation device 51a performs a predetermined process. The failure is recognized according to the communication control procedure, and the data that was being sent at the time of the failure is retransmitted via the detour transmission path 54, but a predetermined communication path recovery process must be performed prior to the retransmission process. Must be. The recovery process is carried out according to a series of procedures depending on the manner in which the failure occurred, and since the contents are not necessarily simple, it sometimes takes a long time to complete the process.

[0006] In addition, in recent years, as network systems have become wider in area, the number of transmission paths involved in the above-mentioned communication path recovery processing has increased, making the processing more complex, and the time required for the processing has accordingly increased. Therefore, there is an increased risk that a delay will occur in the timing of sending data to the transmission path, resulting in a decrease in communication speed. Furthermore, for example, the transmission line 5
3ab and the detour transmission path 54, data communication between the line accommodation devices 51a and 51b becomes impossible, and the line accommodation device 51b cannot receive data to be transferred to the line accommodation device 51c. Also, data communication between the line accommodation devices 51a and 51c becomes impossible. That is, a failure in a single transmission line often makes data communication impossible in multiple sections connecting line accommodation devices.

[0007] Furthermore, when transmitting each data, a single transmission path is fixedly allocated between each line accommodation device, so the transmission speed of the data changes depending on the increase in traffic or other state changes occurring on the transmission path. It also decreased. SUMMARY OF THE INVENTION An object of the present invention is to provide a communication control method that can avoid deterioration in transmission quality in response to changes in the state of a transmission path in a wide area network system.

[0008]

[Means for Solving the Problems] FIG. 1 is a block diagram of the principle of the present invention. The present invention includes terminal devices 111 and 112 that exchange data facing each other, and a plurality of transmission paths 121.
~12N and are connected oppositely via transmission paths 121 to 12N, and those transmission paths and terminal devices 111, 1
In a network system, the line accommodation devices 131 and 132 each have a plurality of transmission paths depending on the importance of the transmitted data, respectively. 12N and sends the transmitted data in parallel to a plurality of transmission paths; It is characterized by comprising a reception control means 15 for providing information to a destination terminal device.

[0009]

[Operation] According to the present invention, the transmission control means 14 selects a plurality of transmission paths from the transmission paths 121 to 12N according to the importance of the transmission data, and sends the transmission data to these transmission paths in parallel. The reception control means 15 of the line accommodation device facing each other via 121 to 12N extracts and reproduces the transmitted data from the data received via the plurality of transmission paths described above.

That is, even if a failure occurs in the transmission line actually used for sending and receiving data, the reception control means 15 can receive the data via another normal transmission line among the plurality of transmission lines mentioned above. Since the transmission data can be extracted and reproduced from the transmitted data, there is no need to newly perform communication path recovery processing in response to the occurrence of a failure in the transmission path, as in the conventional example. Further, even if the traffic volume or other conditions of the plurality of transmission paths mentioned above change during communication, the reception control means 15 controls the reception control means 15 to receive the data first among the data received in parallel from these transmission paths. You can import what is given.

[0011] Therefore, even if the above-mentioned failure or state change occurs in the transmission path, data communication can be smoothly continued by avoiding deterioration in transmission quality caused by delays in communication control processing during communication path recovery processing or the like. becomes possible.

0012

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 2 is a diagram showing an embodiment of the present invention. In the figure, parts having the same functions and configurations as those shown in FIG. 5 are designated by the same reference numerals, and the description thereof will be omitted here.

The characteristic feature of the present invention is that in this embodiment, the detour transmission path 54 is not provided, and the line accommodation devices 51a to 5
Line accommodation devices 21a to 21e each replacing 1e
It has the following features. Here, the line accommodation device 21a ~
21e have the same configuration, but for the sake of simplicity, only the detailed configuration of line accommodation device 21a is shown in FIG. That is, in the line accommodation device 21a, the terminal device 52a connected to the outside is the transmission frame management unit 22a.
and is connected to the received frame determination section 23a. The output of the transmission frame management section 22a is sent to the transmission frame multiplexing section 24.
It is connected to transmission lines 53ab, 53ad, and 53ae via a. Furthermore, transmission lines 53ab, 53ad, 53ae
is connected to the received frame management section 25a, and its output is connected to the received frame determination section 23a. In addition, regarding each component of the other line accommodation devices 21b to 21e, the above-mentioned reference numbers 22a, 23a, 24a,
25a, the suffix ``a'' appended to each line accommodation device reference number shall be replaced by the suffix ``a'' appended to each line accommodation device reference number.
It is expressed using reference numbers with "b to e" added.

Regarding the correspondence between this embodiment and the block diagram shown in FIG. 1, the terminal devices 52a to 52e correspond to the terminal devices 111 and 112, and the transmission paths 53ab and
d, 53ae, 53bc, 53be, 53cd, 53c
e and 53de correspond to the transmission lines 121 to 12N, and the line accommodation devices 21a to 21e correspond to the line accommodation devices 131.
, 132, the transmission frame management units 22a to 2
2e and the transmission frame multiplexing units 24a to 24e correspond to the transmission control means 14, and the reception frame management unit 25a
~25e and received frame determination section 23a ~23e
corresponds to the reception control means 15.

FIG. 3 is a diagram illustrating the operation of this embodiment. FIG. 4 is a diagram showing the structure of a transmission frame in this embodiment. The operation of this embodiment will be described below with reference to FIGS. 2 to 4, taking as an example the case where the line accommodation device 21a transmits data to the line accommodation device 21c. In the line accommodation device 21a, the data sent from the terminal device 52a is taken into the transmission frame management section 22a (Fig. 3 ■)
. As shown in FIG. 4, the transmission frame management unit 22a adds transfer destination identification information (indicating the transfer destination line accommodation device 21c), a frame management number field 41, a route information field 42, control information, etc. to the captured data. A frame 43 containing the above is generated. In each frame having such a configuration, a frame management number for identifying the frame is given and set in the frame management number field 41 for each frame. The route information field 42 contains information on a plurality of transmission paths (to which each frame should be transmitted) based on routing information preset in the line accommodation device 21a.
The route information shown in FIGS. 2-2) is set. The transmission frame management unit 22a transmits the frames thus generated frame by frame (Fig. 3).

The transmission frame multiplexing unit 24a takes in the frame and transmits each frame to transmission paths 53ab, 53ad, and 53ae corresponding to the route information of each frame (FIGS. 2-2 and 3-3). line accommodation device 21b,
21d and 21e are transmission lines 53ab and 53, respectively.
The frame transmitted from the line accommodation device 21a via ad and 53ae is sequentially fetched, and the forwarding destination identification information of each frame is referenced to check whether it corresponds to the forwarding destination line accommodation device. Since it is not a line accommodation device,
Based on the preset routing information, the transmission paths 53bc, 53cd, and 53ce that are directly connected (or connected in the shortest possible way) to the transfer destination line accommodation device 21c are selected, and the frame taken into that transmission path is relayed and transferred. (Figure 3 ■). Further, if the line accommodation device 21e recognizes in advance that the transmission line 53ce is out of order, it does not perform relay transfer for that transmission line.

In the line accommodation device 21c, the received frame management unit 25c manages the transmission lines 53bc, 5 in this manner.
Each frame relayed and transferred via 3cd is captured. The received frame management unit 25c has a frame management number list and a route information list, and stores the contents of the frame management number field 41 (
Hereinafter, it will simply be referred to as a "frame management number." ) is already registered on the frame management number list.

When the received frame management unit 25c determines that the frame management number is not registered in the frame management number list, the received frame management unit 25c determines whether the frame is received first among those assigned the same frame management number. The frame management number is recognized as a frame management number and registered in the frame management number list. Further, the received frame management unit 25c extracts information (from the contents of the route information field 42) indicating a transmission path on which a frame with the same frame management number has not been received yet.
Hereinafter, this will simply be referred to as "route information." ), and after registering the route information in the route information list, the received frame is sent to the received frame determination unit 23c (FIG. 3).

Further, if the frame management number is already registered on the frame management number list, the received frame management unit 25c determines that the frame is received with a delay from the first received frame. The route information of the corresponding received frame is deleted from the route information list and the frame is sent to the received frame determination section 23c (FIG. 3). If all route information corresponding to the same frame management number is deleted by such route information list deletion processing, the received frame management unit 25c determines that all frames assigned the same frame management number are not received. The frame management number is determined to be a frame management number, and the frame management number is deleted from the frame management number list.

Furthermore, the received frame management section 25c:
In order to cope with a failure of the transmission line or line accommodation equipment that performs data relay transfer, if all frames assigned the same frame management number are not received within a predetermined time, the reception standby for the remaining frames is activated. Cut. for example,
As described above, when the transmission line 53ce is out of order, the received frame management unit 25c uses the received frame determination unit 23c.
Only two frames relayed and transferred via the line accommodation devices 21b and 21d are given to .

[0021] If the received frame management section 25c can recognize the above-mentioned failure in advance, it may exclude frames that cannot be received due to the failure from the reception standby target. Further, the received frame management unit 25c sequentially sends the frames received as described above to the received frame management unit 23.
For example, when all frames with the same frame management number are received, or when waiting for unreceived frames is terminated due to a failure in the transfer path, all the frames that have already been received Frames may be sent out all at once.

[0022] The received frame determining unit 23c may, for example, compare the contents of the plurality of frames given in this way and make a majority decision, or use selection criteria based on a predetermined priority order set on the transmission path or other selection criteria. A single piece of data is selected and sent to the terminal device 52c (FIG. 3). In this way, according to this embodiment, a plurality of transmission paths are selected that connect the line accommodation devices that exchange data facing each other, and the same data is exchanged in parallel via these transmission paths. Therefore, even if a failure occurs in any of the transmission paths, data exchange can be continued via another normal transmission path without performing a new communication path recovery process as in the conventional example.

[0023] Furthermore, the handling of received frames in the received frame management section or the received frame judgment section is not limited to the smooth continuation of data exchange in response to failures in the transmission line or other parts during communication, as described above, but also, for example, By capturing the first legitimate frame received among multiple identical frames, the transmission speed can be increased depending on the traffic volume and other network system conditions, and multiple received frames can be compared with each other. This may be used to increase the accuracy of determining the normality of received data.

[0024] In this embodiment, the transmission data is divided and transmitted as frames according to a predetermined frame structure, but the transmission method of the transmission data is not limited to such frames; for example, a predetermined format It may also be transmitted as a packet. In addition, regarding the transmission path method, IS
The present invention is not limited to DN or other digital lines, but can also be applied to, for example, analog lines that transmit digital information using a modem.

Furthermore, the method for determining the combination of a plurality of transmission paths selected by the line accommodation device when transmitting data can be set as appropriate depending on the specifications of the system including the above-mentioned network system. It may be set variably depending on the importance of the corresponding transmission path (transmission data).

[0026]

Effects of the Invention As explained above, in the present invention, the reception control means connected to the terminal to which the transmission data is transferred is able to control the reception control means among the plurality of transmission paths even if a failure occurs in the transmission path during communication. Since the same data can be retrieved from another normal transmission path and the transmitted data can be extracted and reproduced, it is possible to continue data communication smoothly without performing a new communication path recovery process. In addition, the reception control means can take in the first one of the same data received from multiple transmission paths in parallel, so even if the traffic volume or other state changes on the transmission path, A decrease in transmission speed caused by this can be avoided.

[0027] Therefore, in response to the progress of network systems becoming wider, it is possible to improve the reliability of communication lines and maintain high transmission quality.

[Brief explanation of the drawing]

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

FIG. 2 is a diagram showing an embodiment of the present invention.

FIG. 3 is a diagram illustrating the operation of this embodiment.

FIG. 4 is a diagram showing the structure of a transmission frame in this embodiment.

FIG. 5 is a diagram showing a configuration example of a conventional network system.

[Explanation of symbols]

11, 52 Terminal device 12,53 Transmission line 13, 21, 51 Line accommodation device 14 Transmission control means 15 Reception control means 22 Transmission frame management section 23 Received frame determination unit 24 Transmission frame multiplexing unit 25 Received frame management section 41 Frame management number field 42 Route information field 43 Transmission frame 54 Detour transmission line

Claims (1)

[Claims] [Claim 1] A terminal device that exchanges data face-to-face (
111, 112) and multiple transmission lines (121 to 1
2N ) and the terminal device (
111 , 112 ), the network system includes line accommodation devices ( 131 , 132 ) that interface with the line accommodation devices ( 131 , 112 ), respectively.
1, 132), a plurality of transmission paths are connected to the transmission paths (121 to 12N) according to the importance of the transmission data, respectively.
) and sends the transmitted data to the plurality of transmission paths in parallel; A communication control system characterized by comprising a reception control means (15) for extracting and reproducing the extracted data and providing it to a destination terminal device.