JPH0955759A - Multi-station communication device using ring transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize nearly the same signal transmission state as an ordinary state by incorporating a means which sends a signal indicating a sent signal break in a monitor means and a means which sends out an emergency signal in a transmitting means. SOLUTION: A means 14 which takes a local-station arrival channel signal from a stand-by transmission line 22 when detecting a break of a sent signal or characteristic deterioration of a transmission line and the means 15 which informs a transmitting means 12 of a signal indicating the break of the sent signal are incorporated in the monitor means 14 for the sent signal, and the means 16 which sends the emergency signal to all channels except the local- station arrival channel is incorporated in the transmitting means 12. If the transmission line or device gets out order on a ring-shaped in-use transmission line 21, respective stations informed of that are switched to reception from a stand-by transmission line 22. Therefore, a normal communication wherein the transmission of signals is not delayed is always maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-station communication device using a dual ring transmission line which can communicate without a signal transmission delay when a failure occurs.

[0002]

2. Description of the Related Art Current and standby systems (commonly called 0 system and 1 system)
The duplexed transmission line connects a large number of signal transmission stations in a ring shape, and a dedicated channel (time slot) is dedicated between the stations for communication.

That is, the format shown in FIG. 6 indicates that communication is performed by the channels of numbers 1 to n following the synchronization signal F. For example, the channel with the number m is set in advance between the stations A and B shown in FIG. 7, and the channel with the number p is used between the stations C and D in advance. FIG. 7 schematically shows the duplicated transmission line. In FIG. 7, A station, B station, C station, and D station do not have upper and lower hierarchical differences on the transmission path, and transmit between the active system (0 system) shown by the solid line and the standby system (1 system) shown by the dotted line. The road is connected. Although an exclusive input / output device is connected to each station, its illustration is omitted.

When the channel is abbreviated as CH, CH1
Between stations A and C, CH2 between stations A and C, CH
3 is between stations A and D, CH4 is between stations B and D, C
H5 is set to be used for communication between the C station and D station. Now, it is assumed that the active system (0 system) is in use and the standby system is on standby, and a failure occurs between the A station and the B station on the active system transmission path. When the station B detects the occurrence of the failure, it instructs the standby system 1 transmission path to switch to the active mode. It suffices to transmit the instruction to the A station through the 1-system transmission line from the B station, and then the A station transmits the instruction to the next D station. As a result, the 1-system transmission path also becomes ring-shaped.

However, it is only the station B that has detected the fault in the 0-system transmission line, and not the signal transmitted from the A station in the 0-system transmission line from the B station, but the transmitting means in the B station. The signal transmitted by is transmitted. Regardless of the legitimacy of the signal from station B and beyond, the transmission line is operating with the signal present, so each station after station B begins to transmit the legitimate signal through the 1-system transmission line. I can't know.

Therefore, the operation cannot be switched so that the signal is taken out from the 1-system in which the legitimate signal is transmitted. This is because the conventional signal transmission station does not have a means effective for channel switching or a pickup means.

Therefore, at the station B, the folded line FL shown in FIG. 7 is formed. The folded line FL is a connection line that short-circuits the 0-system transmission line and the 1-system transmission line in the B station.
When the folded line FL is connected, the signal of the 1-system transmission line is
The data is divided in the B station and transmitted as a predetermined signal in the 0-system transmission line. Therefore, the station C can take out the signal addressed to itself from the 0-system transmission line and send the other signals to the station D as before, regardless of the presence / absence of the failure of the station B.

[0008]

In the above case, for example, in the D station, a signal that is completely the same as the conventional one is transmitted and received by the CH3, CH4, and CH5 channels through the 0-system transmission line. When CH5 is examined, it is a signal transmitted as C → D (folded line) using the 1-system transmission line and C → D using the B → 0-system transmission line. Therefore, the signal is transmitted over a long distance as compared with the case where the signal was originally transmitted from the C station to the D station using only the 0-system transmission line, and therefore the transmission delay of the signal cannot be avoided. Is.

An object of the present invention is to remedy the above-mentioned drawbacks, in which each signal transmission station forming a ring-shaped transmission path is triggered by an emergency signal from the signal transmission station which has detected the occurrence of a failure in the transmission path, An object of the present invention is to provide a multi-station communication device that can obtain a signal transmission state that is almost the same as a normal state by accessing a transmission path of another system.

[0010]

FIG. 1 shows a principle block diagram for the invention according to claim 1. In FIG. 1, 10 is a signal transmission station, 11 is a monitoring means for constantly monitoring a channel signal transmitted from another station, 12 is a transmission means, 13 is a signal transmission path, and 14 is a backup system for a local arrival channel signal. Means for taking out from the transmission path, 15 means for notifying the transmission means, 16 for emergency signal transmission means, 21 for the active transmission path, and 22 for the standby transmission path.

According to the first aspect of the present invention, the monitoring means 11 for constantly monitoring the channel signal transmitted from another station, and the local station originating channel signal included in the same channel when the local station arriving channel signal is received. A signal transmission station 10 having a transmission means 12 for transmitting and transmitting the signal, and the signal transmission station 10 and the signal transmission line 1.
In a multi-station communication device using a ring transmission line which comprises a ring transmission line composed of 3 and a backup transmission line 22 in the opposite direction of the same type as the working transmission line, monitoring of said transmission signal The means 11 extracts the local arrival channel signal from the standby system transmission path 22 when detecting the transmission signal disconnection or the characteristic deterioration of the transmission path, and the means 15 for notifying the transmission means 12 of the transmission signal disconnection signal. And the transmitting means 12 is configured to include means 16 for transmitting an emergency signal to all channels other than the self-arrival channel in response to the notified signal.

When a plurality of signal transmission lines 13 and a plurality of signal transmission stations 10 are connected to each other to form a ring-shaped transmission line, the monitoring means 11 of the signal transmission station constantly monitors the signals transmitted from other stations. I'm watching. The monitoring means 11 is the active transmission line 2
When the disconnection of the transmission signal in 1 is detected, the backup transmission line 2
2 is started, and the local station arrival channel signal is extracted from the signal transmitted through the standby system transmission line 22. Further, the transmission means 12 of the own station is notified of the transmission signal disconnection.

The transmitting means 12 sends out an emergency signal (a signal for reporting the occurrence of a failure) as a signal to be transmitted to another station via the active transmission line 21. The signal transmitted from this signal transmission station to another station via the backup transmission line does not include an emergency signal. The invention according to claim 2 describes the limiting condition for the signal transmission station that has received the signal of the working transmission path in which the emergency signal is inserted. That is, the signal transmission station is equipped with an incoming call changeover switch for the active system transmission line and the standby system transmission line, and when the monitoring means detects that the channel signal for the station is an emergency signal, that channel Only, the access is changed to the standby system transmission line 22 for reception.

Next, the signal transmitted through the ring-shaped signal transmission line is a signal of the synchronous digital hierarchy (SDH) format, and the emergency signal has an alarm transfer function of the same format. It is configured by being transmitted by. According to the present invention, since the emergency signal is transmitted by the alarm transfer function, it is one type of maintenance operation signal transmission,
Correspondence of processing can be effective.

[0015]

FIG. 2 is a block diagram specifically showing FIG. In FIG. 2, reference numerals 21 and 22 denote the active system (0
(System) transmission line and standby transmission line, 30 is a signal transmission station, 31 is a monitoring means, 32 is a transmission means, 31 and 32 after the signal transmission station 30 correspond to 10, 11, and 12 in FIG. 1, respectively. To do.

Next, the "REC" 33 is a failure detection unit, which detects the occurrence of a failure when the frame synchronization cannot be established due to a signal interruption or the like. Also, the abnormality notification signal detection unit 3
Reference numeral 4 indicates a location where the transmitted emergency signal is detected.
Reference numeral 35 denotes a 0/1 switching unit, which is a switch for switching the connection to the other transmission line when an emergency signal is detected on the transmission line.

Of the transmitting means 32, the abnormality notification signal generator 3
Reference numeral 6 indicates a portion for generating an emergency signal. The frame synchronizing unit, the speed converting unit, the multiplexing, etc. in the station show the normal operation points in the normal signal transmission station, and therefore their explanations are omitted.
FIG. 3 is a diagram showing an example of a channel signal format in the case of each state in the B station of FIG. 2, for example. FIG. 3A shows the state of the REC signal during use of the active transmission path. It is assumed that a failure occurs at time T1 and the signal of the REC section changes from “0” to “1”, for example.

FIG. 3B shows a received data format that the station B is receiving. F is a synchronizing signal, and 1, 2, 3, ... N are channel numbers. FIG. 3C shows the output of the 0/1 system switching unit 35, and shows the signal instructing the standby system switching at time T2.

FIG. 3D shows a transmission signal transmitted from the station B to another station via the working transmission path. After time T2, the hatched portion indicates that the emergency signal is transmitted. R
When an EC is detected, an emergency signal is inserted except for the channel used by the own station. Further, the fact that the channels 1 and 4 are not hatched indicates that the channel is a channel received by the B station. In this way, only the transmission station that has detected the abnormality sends a special signal.

FIG. 4 is a diagram showing a data format in the D station which is ring-connected to the B station shown in FIG. FIG. 4A shows a REC signal during use of the working transmission path, and no abnormality is detected in the D station. FIG. 4B shows received data, and the signal shown in FIG. 3D arrives at station D via station C via the active transmission path. At this time, as for channels 2 and 5, since the C station on the way is a channel used for another station, in this case, for A and D, the C station inserts a normal communication signal instead of the emergency signal. ing.

Channel 3 in the received data shown in FIG. 4B.
Since the signals other than the channel 6 are all emergency signals, the 0/1 system changeover switch 4 which has detected the signal switches from the 0 system to the 1 system at the position of the channel 3 as shown in FIG. 4C. As described above, according to the first aspect of the invention, the signal transmitted from the previous station is transmitted through to the subsequent station on the transmission path except the channel used in the own station. In FIG. 4, it can be seen from FIG. 4D that the emergency signal is inserted after channel 6 and before the channel indicated by F.

This emergency signal is determined by performing parallel-serial conversion for each channel and determining whether or not it coincides with a predetermined emergency signal. Also, for the matching determination, detection of "the number of protection steps n times (where n is an integer of 2 or more)" is a necessary condition. FIG. 5 is a diagram schematically showing an SDH ring transmission system. In FIG. 5, the 0-system transmission path from the B station transmits an emergency signal for transmitting the failure of the transmission path detected by the B station to the C station and thereafter. For example, all "1" signals are used as the respective AIS signals of the TU2, TU3, and TU4 channels. When this signal is received by the C station and the D station, the reception transmission path is switched from the 0 system to the 1 system. The transmission of the emergency signal is the same in the case of a device failure other than the failure of the transmission path. SD
The H transmission system has been practically used between opposite stations,
As a ring transmission system, the abnormality detection signal was not transmitted and the transmission line was not switched.

[0023]

According to the first aspect of the present invention, when a failure occurs in the transmission path / device in the ring-shaped working transmission path, each station notified of the failure switches to receiving from the protection transmission path. Execute the process. Therefore, normal communication can always be performed without causing signal transmission delay.

According to the second aspect of the present invention, the transmission line can be switched by utilizing the alarm transfer function in the SDH type transmission line. Therefore, it is not necessary to transmit the emergency signal using the user bit on the transmission path, and it is not necessary to manage the communication protocol.

[Brief description of drawings]

1 shows a principle block diagram for the invention according to claim 1;

FIG. 2 is a configuration diagram specifically showing FIG.

FIG. 3 is a diagram showing a channel signal format in station B of FIG.

FIG. 4 is a diagram showing a signal format in station D of FIG.

FIG. 5 is a diagram schematically showing an SDH ring transmission system.

FIG. 6 is a diagram showing a format of inter-station communication.

FIG. 7 is a diagram showing a duplicated transmission path.

[Explanation of symbols]

10 signal transmission station 11 monitoring means 12 transmission means 13 signal transmission path 14 means for extracting own-station arriving channel signal from standby system transmission path 15 means for notifying transmission means 16 emergency signal transmission means 21 working system transmission path 22 standby system transmission Road

Claims (3)

[Claims] 1. A monitoring means for constantly monitoring a channel signal transmitted from another station, and a transmitting means for transmitting a channel signal originating from the local station when the channel signal received from the local station is received. A ring transmission line is formed by a signal transmission station provided with the signal transmission station and the signal transmission line, and a ring transmission line having a backup system transmission line of the same type as the working system transmission line in the opposite direction is used. In the inter-station communication device, when the transmission signal monitoring means detects a transmission signal disconnection or characteristic deterioration of the transmission path, the local station arrival channel signal is taken out from the standby system transmission path, and the transmission signal is disconnected to the transmission means. A ring for transmitting an emergency signal to all channels other than the own-arrival channel in response to the notified signal. Transmission line Multi station communication apparatus used. 2. The signal transmission station according to claim 1, further comprising an incoming call changeover switch for the working transmission path and the protection transmission path, and the monitoring means for the transmission signal in the signal transmission station is the emergency transmission device according to claim 1. A signal transmission station for use in a multi-station communication device, which transmits a signal for switching the incoming call changeover switch when it detects that a reception signal has been received. 3. A signal transmitted by a ring-shaped signal transmission line is a signal of a synchronous digital hierarchy (SDH) format, and an emergency signal is transmitted by an alarm transfer function of the same format signal. The multi-station communication device according to claim 1.