JP2004015173A - Channel change method for virtual concatenation and transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmitter capable of increasing a transmission amount by efficiently using a transmission band during the normal operation of a ring network while ensuring signal transmission at a fault time. <P>SOLUTION: Upon detecting warning indicating the occurrence of a fault in channels VC1, VC2, a receivier 11-3 deletes the channels VC1, VC2 in which the fault occurs from a received virtual concatenation signal. Further, the receiver 11-3 transmits warning transfer information indicating the occurrence of the faults occurring in the channels VC1, VC2 to a transmitter 11-1. Upon detecting the warning transfer information, the transmitter 11-1 deletes the channels VC1, VC2 having the faults from the virtual concatenation signal under transmission. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an SDH ring network, and more particularly to an improvement in reliability and utilization efficiency of a transmission path of an SDH network.
[0002]
[Prior art]
The SDH hierarchy is defined mainly for transmitting voice service signals. However, in recent years, the traffic volume of data-based services in addition to voice-based services has been rapidly increasing. Therefore, there is a growing demand for efficiently transmitting data service signals in an SDH network.
[0003]
There are various data rates for data services represented by Ethernet. The conventional SDH hierarchy has not been able to efficiently accommodate signals for these data services. Therefore, various attempts have been made to efficiently accommodate data service signals in the SDH hierarchy. In order to efficiently accommodate data service signals in the SDH hierarchy, ITU-TG. 707 et al. Recommend a virtual concatenation technology.
[0004]
According to the virtual concatenation, by connecting (concatenating) N (N is arbitrary) SDH paths, a virtual concatenation signal having a transmission band of an arbitrary multiple (N times) of the transmission band of the SDH path can be configured. . As a result, it becomes possible to accommodate data services at various data rates in the SDH network.
[0005]
In addition, the SDH network has a large transmission band and a high public nature, so that high reliability against failure is required. Therefore, in the SDH network, a redundant configuration is often adopted in order to enhance reliability against a failure. For example, in an SDH ring network, a double ring-type transmission line is configured, an active transmission line and a spare transmission line are made to correspond one-to-one, and half of the transmission line is reserved.
[0006]
In a conventional SDH ring network having a redundant configuration, for example, when a failure occurs in a transmission path, signal transmission can be restored in a short time by switching to a spare transmission path.
[0007]
[Problems to be solved by the invention]
In order to cope with the recent increase in the traffic volume of data services, it is required to increase the transmission band of the SDH network. However, a conventional SDH ring network having a redundant configuration waits without using a spare transmission line in a normal state in order to enhance reliability. That is, a considerable part of the transmission band of the SDH ring network is unused, and the transmission band is wasted in a normal state.
[0008]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a transmission apparatus capable of securing signal transmission at the time of a failure and increasing a communication amount by effectively using a transmission band when a ring network is operating normally.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a method for changing a channel of virtual concatenation according to the present invention provides a virtual concatenation in a transmission system having a function of forming a virtual concatenation signal by connecting a plurality of channels from a transmission device to a reception device. Channel change method,
In the receiving device,
Upon detecting an alarm indicating that a failure has occurred in the channel, removing the failed channel from the received virtual concatenation signal,
Transmitting to the transmitting device alarm transfer information indicating that a failure has occurred in the channel,
In the transmitting device,
When detecting the alarm transfer information, the method includes a step of deleting the failed channel from the transmitted virtual concatenation signal.
[0010]
Therefore, according to the channel changing method of the present invention for virtual concatenation, when a failure occurs in a channel (path corresponding to a virtual container in the embodiment of the present invention) constituting a virtual concatenation signal, the receiving device issues an alarm. Detecting and deleting the channel from the virtual concatenation signal, and transmitting the alarm transfer information to the transmission device. When the transmission device receives the alarm transfer information, the transmission device deletes the channel from the virtual concatenation signal.
[0011]
In the receiving device,
Upon detecting the elimination of the alarm of the channel, re-adding the channel whose alarm has been eliminated to the virtual concatenation signal;
Stopping transmission of the alarm transfer information to the transmitting device;
In the transmitting device,
The method may further include the step of, when detecting the suspension of the alarm transfer information, adding the channel for which the alarm has been canceled to the virtual concatenation signal again.
[0012]
In addition, there may be a plurality of transmission paths from the transmission device to the reception device, and the plurality of channels from the transmission device to the reception device may be distributed over the plurality of transmission lines.
[0013]
Further, the alarm transfer information may be transferred by path overhead.
[0014]
The transmission device of the present invention is a transmission device that transmits and receives a virtual concatenation signal in which a plurality of channels are connected,
Upon detecting an alarm indicating that a failure has occurred in the received channel, a receiving unit that deletes the channel from the virtual concatenation signal on the receiving side,
When the receiving unit detects that a failure has occurred in the received channel, it transmits alarm transfer information indicating that a failure has occurred in the channel to the transmission source of the channel. When receiving the alarm transfer information indicating that the alarm has occurred, the transmission unit deletes the channel from the virtual concatenation signal on the transmission side.
[0015]
Note that, when detecting the cancellation of the received alarm of the channel, the receiving unit adds the channel again to the virtual concatenation signal of the receiving side,
The transmitting unit, when the cancellation of the received alarm of the channel is detected by the receiving unit, stops transmitting the alarm transfer information, and transmits the alarm transfer information indicating that a failure has occurred in the transmitted channel. When the stop is detected, the channel may be added again to the virtual concatenation signal on the transmitting side.
[0016]
Further, signals may be transmitted and received by a plurality of transmission paths, and the plurality of channels may be distributed to the plurality of transmission paths.
[0017]
Further, the alarm transfer information may be transferred by path overhead.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described in detail with reference to the drawings.
[0019]
FIG. 1 is a block diagram illustrating a configuration of the transmission system according to the present embodiment. Referring to FIG. 1, the transmission system 10 has nodes 11-1 to 11-4. All nodes 11-1 to 11-4 have the same configuration. The transmission system 10 is an SDH ring network in which nodes are connected by double ring transmission paths 13 and 14, and accommodates data-based services using virtual concatenation. The transmission line 13 is a clockwise outer ring, and the transmission line 14 is a counterclockwise inner ring. Different numbers (virtual container numbers) are assigned to the channels (virtual containers) of the transmission paths 13 and 14.
[0020]
Hereinafter, attention is paid to the communication between the nodes 11-1 and 11-2.
[0021]
Data transmitted and received between the nodes 11-1 and 11-3 is transmitted through both the clockwise transmission line 13 and the counterclockwise transmission line 14. Further, a virtual concatenation signal is set from the node 11-1 to the node 11-3. The virtual concatenation signal includes four channels of virtual containers VC1 to VC4. The virtual containers VC1 and VC2 are channels on the transmission path 13, and the virtual containers VC3 and VC4 are channels on the transmission path.
[0022]
Each of the nodes 11-1 and 11-3 has a band changing unit 12. The band changing unit 12 forms a virtual concatenation signal by connecting a plurality of virtual containers, and transmits and receives the virtual concatenation signal to and from the user device. The band changing unit 12 monitors the state of the virtual container, changes the virtual container forming the virtual concatenation signal based on the monitoring result, and changes the band of the virtual concatenation signal.
[0023]
FIG. 2 is a block diagram illustrating a configuration of each node according to the present embodiment. The nodes 11-1 to 11-4 in FIG. 1 have the same configuration, and are shown as nodes 11 in FIG. Referring to FIG. 2, the node 11 has a receiving unit 21 and a transmitting unit 22 in the band changing unit 12.
[0024]
The receiving unit 21 processes data in a direction from another node to the user device, and the transmitting unit 22 processes data in a direction from the user device to another node.
[0025]
The receiving unit 21 has a band generation unit 23, an alarm detection unit 24, and a band control unit 25.
[0026]
The transmission unit 22 includes a band generation unit 26, an alarm transfer information generation unit 27, a band control unit 28, and an alarm transfer information detection unit 29.
[0027]
The band generator 23 receives signals from the two transmission lines 13 and 14. In accordance with a predetermined setting from a network management unit (not shown), the band generation unit 23 extracts and connects virtual containers from the signals of the transmission lines 13 and 14, generates a virtual concatenation signal, and generates a virtual concatenation signal. ). Further, the band generation unit 23 changes the virtual container connected to one virtual concatenation signal according to the instruction from the band control unit 25.
[0028]
The alarm detection unit 24 receives signals from the two transmission paths 13 and 14. The alarm detector 24 monitors signals from the transmission lines 13 and 14 and detects an alarm. When an alarm is detected, the alarm detection unit 24 notifies the band control unit 25 and the alarm transfer information generation unit 27 of the path number of the path where the alarm was detected (hereinafter, referred to as a defective path number). Here, the alarm is, for example,
In addition to deterioration of the bit error rate of the path, transmission path failure, loss of frame synchronization, etc., occur when the signal of the path is not transmitted normally.
[0029]
In addition, the alarm detection unit 24 detects that the alarm has been eliminated, and notifies the band control unit 25 and the alarm transfer information generation unit 27 of the path number of the path from which the alarm has been eliminated.
[0030]
The band control unit 25 instructs the band generation unit 23 to delete the virtual container corresponding to the bad path number notified from the alarm detection unit 24 from the virtual concatenation signal.
[0031]
Further, when notified of the cancellation of the alarm from the alarm detection unit 24, the band control unit 25 instructs the band generation unit 23 to add the virtual container corresponding to the path number to the original virtual concatenation signal. .
[0032]
The band generation unit 26 receives a signal from a user device (not shown). The band generation unit 26 distributes the signal to the virtual containers constituting the virtual concatenation signal according to a predetermined setting from a network management unit (not shown). In addition, the band generation unit 26 changes the virtual container forming one virtual concatenation signal according to an instruction from the band control unit 28. At that time, the band generation unit 26 temporarily deletes or adds the virtual container number registered in the virtual concatenation group. The virtual concatenation group is a group composed of virtual containers constituting each virtual concatenation signal.
[0033]
When notified of the faulty path number from the alarm detection unit 24, the alarm transfer information generation unit 27 transmits alarm transfer information indicating that an alarm has occurred on the path to the transmission source node of the path. The alarm transfer information is transferred by a path overhead (hereinafter, referred to as POH) corresponding to the path, and is continuously transferred as long as an alarm occurs.
[0034]
In addition, the alarm transfer information generation unit 27 stops the transfer of the alarm transfer information when notified of the cancellation of the alarm from the alarm detection unit 14.
[0035]
The band control unit 28 instructs the band generation unit 26 to delete the virtual container corresponding to the bad path number notified from the alarm transfer information detection unit 29 from the virtual concatenation signal.
[0036]
When notified of the path number of the path from which the alarm transfer information has disappeared from the alarm transfer information detecting section 29, the band control section 28 adds the virtual container corresponding to the path number to the original virtual concatenation signal. Then, it instructs the band generation unit 27.
[0037]
The alarm transfer information detecting unit 29 receives signals from the two transmission lines 13 and 14. The alarm transfer information detection unit 29 monitors the POH of the signal on each of the transmission lines 13 and 14 and detects alarm transfer information. Upon detecting the alarm transfer information, the alarm transfer information detection unit 29 notifies the band control unit 28 of the path number (defective path number) of the path where the alarm transfer information is detected.
[0038]
Further, when the alarm transfer information that has been detected until then disappears, the alarm transfer information detection unit 29 notifies the band control unit 28 of the path number of the path from which the alarm transfer information has disappeared.
[0039]
Operations of the transmission system 10 and the node 11 according to the present embodiment will be described.
[0040]
FIG. 3 is a diagram for explaining operations of the transmission system and the nodes according to the present embodiment.
[0041]
A virtual concatenation signal is set from the node 11-1 to the node 11-3. The virtual concatenation signal includes four channels of virtual containers VC1 to VC4. The virtual containers VC1 and VC2 are channels on the transmission path 13, and the virtual containers VC3 and VC4 are channels on the transmission path.
[0042]
Here, it is assumed that a failure has occurred in the virtual containers VC1 and VC2 between the nodes 11-1 and 11-2 of the transmission path 13 as shown in FIG.
[0043]
The node 11-3 detects the alarm of the path corresponding to the virtual containers VC1 and VC2 by the alarm detection unit 24.
[0044]
In the node 11-3, the path number of the path where the alarm is detected is notified from the alarm detection unit 24 to the band control unit 25 and the alarm transfer information generation unit 27. Upon receiving the notification from the alarm detection unit 24, the band control unit 25 instructs the band generation unit 23 to delete the virtual containers VC1 and VC2 from the virtual concatenation signal. The band generation unit 23 deletes the virtual containers VC1 and VC2 from the virtual concatenation signal according to an instruction from the band control unit 25. Further, in response to the notification from the alarm detection unit, the alarm transfer information generation unit 27 transmits alarm transfer information indicating that an alarm has occurred on those paths to the node 11-1.
[0045]
The node 11-1 detects the alarm transfer information of the path corresponding to the virtual containers VC1 and VC2 by the alarm transfer information detecting unit 29.
[0046]
In the node 11-1, the path number of the path where the alarm transfer information is detected is notified from the alarm transfer information detection unit 29 to the band control unit 28. Upon receiving the notification from the alarm transfer information detecting unit 29, the band control unit 28 instructs the band generating unit 26 to delete the virtual containers VC1 and VC2 from the virtual concatenation signal. The band generation unit 26 deletes the virtual containers VC1 and VC2 from the virtual concatenation signal according to an instruction from the band control unit 28.
[0047]
It is also assumed that the failure of the transmission path 13 has been resolved.
[0048]
The node 11-3 uses the alarm detection unit 24 to detect that the alarm of the path corresponding to the virtual containers VC1 and VC2 has been cancelled.
[0049]
In the node 11-3, the alarm detection unit 24 notifies the band control unit 25 and the alarm transfer information generation unit 27 of the path number of the path where the cancellation of the alarm is detected. Upon receiving the notification from the alarm detection unit 24, the band control unit 25 instructs the band generation unit 23 to add the virtual containers VC1 and VC2 to the original virtual concatenation signal. The band generation unit 23 adds the virtual containers VC1 and VC2 to the original virtual concatenation signal according to the instruction from the band control unit 25. Further, upon receiving the notification from the alarm detection unit, the alarm transfer information generation unit 27 stops transmitting the alarm transfer information to the node 11-1.
[0050]
The node 11-1 detects that the alarm transfer information of the path corresponding to the virtual containers VC1 and VC2 has been stopped by the alarm transfer information detection unit 29.
[0051]
In the node 11-1, the alarm transfer information detecting unit 29 notifies the band control unit 28 of the path number of the path in which the suspension of the alarm transfer information is detected. Upon receiving the notification from the alarm transfer information detecting unit 29, the band control unit 28 instructs the band generating unit 26 to add the virtual containers VC1 and VC2 to the original virtual concatenation signal. The band generation unit 26 adds the virtual containers VC1 and VC2 to the original virtual concatenation signal according to the instruction from the band control unit 28.
[0052]
As described above, according to the transmission system of the present embodiment, when a failure occurs in a path corresponding to a virtual container constituting a virtual concatenation signal, a node on the receiving side of the path detects an alarm, While deleting the virtual container from the virtual concatenation signal on the receiving side, and transmitting the alarm forwarding information to the node on the transmitting side, when the node on the transmitting side receives the alarm forwarding information, the node on the virtual concatenation signal on the transmitting side receives the alarm forwarding information. Since the virtual container is deleted, in the normal state, a wide transmission band is used for communication, and in the failure state, the virtual concatenation signal is maintained only on the path without the failure, and the effective use of the transmission band and high reliability for the failure Sex can be compatible.
[0053]
Here, the transmission system 10 exemplifies a configuration in which the nodes 11-1 to 11-4 are connected by two ring transmission paths 13 and 14, a clockwise outer ring and a counterclockwise inner ring. However, the number of transmission paths of the present invention is not limited to two. In the transmission system of the present invention, it is preferable that there are a plurality of transmission paths, and the virtual containers forming the virtual concatenation signal are distributed over the plurality of transmission paths. In this case, as shown in FIG. 4, the configuration of the node 11 transmits and receives signals through a plurality of (n) transmission paths.
[0054]
Further, here, the configuration in which the nodes 11-1 to 11-4 are connected by the ring-type transmission lines 13 and 14 is illustrated, but the transmission line of the present invention is not limited to the ring type. The present invention can be applied to any transmission system to which virtual concatenation is applied.
[0055]
【The invention's effect】
According to the present invention, when a failure occurs in a channel constituting the virtual concatenation signal (path corresponding to the virtual container in the embodiment of the present invention), the receiving apparatus detects an alarm and outputs the alarm from the virtual concatenation signal. In addition to deleting the channel, transmitting the alarm transfer information to the transmitting device, and upon receiving the alarm transfer information, the transmitting device deletes the channel from the virtual concatenation signal. Is used for communication, and in the failure state, the virtual concatenation signal is maintained only in the channel without the failure by recognizing by the devices on the transmitting side and the receiving side, so that the effective use of the transmission band and high reliability for the failure Sex can be compatible.
[Brief description of the drawings]
FIG.
FIG. 1 is a block diagram illustrating a configuration of a transmission system according to an embodiment.
FIG. 2
FIG. 2 is a block diagram illustrating a configuration of each node according to the embodiment.
FIG. 3
FIG. 3 is a diagram for explaining operations of the transmission system and the node according to the embodiment.
FIG. 4
FIG. 3 is a block diagram illustrating a configuration of a node having a plurality of transmission paths according to the present embodiment.
[Explanation of symbols]
Reference Signs List 10 Transmission system 11-1 to 11-4 Node 12 Band changing unit 13, 14 Transmission line 21 Receiver 22 Transmitter 23 Band generator 24 Alarm detector 25 Band controller 26 Band generator 27 Alarm transfer information generator 28 Band Control unit 29 Alarm transfer information detection unit

Claims (8)

A method for changing a channel of virtual concatenation in a transmission system having a function of connecting a plurality of channels from a transmitting device to a receiving device to form a virtual concatenation signal,
In the receiving device,
Upon detecting an alarm indicating that a failure has occurred in the channel, removing the failed channel from the received virtual concatenation signal,
Transmitting to the transmitting device alarm transfer information indicating that a failure has occurred in the channel,
In the transmitting device,
A method for changing a channel of a virtual concatenation, comprising the step of, upon detecting the alarm transfer information, deleting the failed channel from the transmitted virtual concatenation signal. In the receiving device,
Upon detecting the elimination of the alarm of the channel, re-adding the channel whose alarm has been eliminated to the virtual concatenation signal;
Stopping transmission of the alarm transfer information to the transmitting device;
In the transmitting device,
2. The virtual concatenation channel changing method according to claim 1, further comprising the step of, when detecting the suspension of the alarm transfer information, adding the channel for which the alarm has been eliminated again to the virtual concatenation signal. The virtual concatenation according to claim 1, wherein there are a plurality of transmission paths from the transmission device to the reception device, and the plurality of channels from the transmission device to the reception device are dispersed in the plurality of transmission lines. Nation channel change method. 4. The method according to claim 1, wherein the alarm transfer information is transferred by path overhead. 5. A transmission device for transmitting and receiving a virtual concatenation signal obtained by connecting a plurality of channels,
Upon detecting an alarm indicating that a failure has occurred in the received channel, a receiving unit that deletes the channel from the virtual concatenation signal on the receiving side,
When the receiving unit detects that a failure has occurred in the received channel, it transmits alarm transfer information indicating that a failure has occurred in the channel to the transmission source of the channel. A transmission device having a transmission unit that, upon receiving alarm transfer information indicating occurrence of the occurrence, deletes the channel from a virtual concatenation signal on the transmission side. Upon detecting the cancellation of the received alarm of the channel, the receiving unit adds the channel again to the virtual concatenation signal of the receiving side,
The transmitting unit, when the cancellation of the received alarm of the channel is detected by the receiving unit, stops transmitting the alarm transfer information, and transmits the alarm transfer information indicating that a failure has occurred in the transmitted channel. 6. The transmission device according to claim 5, wherein upon detecting a stop, the channel is added again to the virtual concatenation signal on the transmission side. The transmission device according to claim 5, wherein signals are transmitted and received by a plurality of transmission paths, and the plurality of channels are distributed to the plurality of transmission paths. The transmission device according to claim 5, wherein the alarm transfer information is transferred by a path overhead.

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