JPWO2014030732A1 - Communication system, communication apparatus, protection switching method and switching program - Google Patents

Abstract

Provided is a communication system that can use a plurality of standby communication channels at low cost. In a communication system that transmits data between a plurality of communication devices via a plurality of communication paths, a working system and a working system that are normally used communication paths are faulty. Communication occurs when a plurality of protection groups, which are pairs of protection systems that are communication paths used in the event of occurrence, are formed, and a failure occurs in both the active system and the protection system of the first protection group. The device uses the spare system of the second protection group as a temporary replacement for the first protection group. [Selection] Figure 1

Description

  The present invention relates to a communication system, a communication apparatus, a protection switching method, and a switching program, and more particularly to a communication system that can quickly switch to a standby system even when multiple failures occur.

  A communication network is always required to improve communication speed and communication capacity, and at the same time, it is also required to improve reliability. In particular, connection types such as SONET (Synchronus Optical Network, Bellcore Recommendation GR-253-CORE issue 2) / SDH (Synchronus Digital Hierarchy, ITU-T G.707) and MLPS-TP (Multi Protocol Label Switching, IETF RFC5654) The (Connection Oriented) communication method is based on the assumption that the connection is always established with the communication partner during the communication, so the communication must not be interrupted. .

  For this reason, in many communication networks, devices are connected by two communication channels, the active system and the standby system, and when the active system fails and communication becomes impossible, the active system is maintained. Therefore, in the case of a temporary stop or the like, a redundant configuration that enables switching to a standby system and continuing communication is employed. In the above-described SONET / SDH, MLPS-TP, and the like, such a set of the active system and the standby system is defined as a protection group.

  The following technologies are related to this. Among them, Patent Document 1 describes a communication network system in which ring networks are connected by a plurality of systems of an active system and a standby system. Patent Document 2 describes a redundant pair system in which a transmission service can be continued even when a failure occurs between a network and an external device by duplicating an SDH device.

  Patent Document 3 describes a signaling processing device that, when switching a communication line from an active system to a standby system, notifies an IP node of information necessary for the switching and speeds up the switching. Patent Document 4 describes a communication device that first attempts to rescue in the active system when a failure occurs, and switches to the standby system if that fails.

  Patent Document 5 describes a technique of stably securing a standby line in a technique called LAG (Link Aggrigation Group) in which a plurality of physical connections are grouped into one logical connection. Yes. Patent Documents 6 and 7 both describe a communication device that secures a plurality of standby systems for the active system and can be switched and used when a failure occurs.

JP 2000-004248 A JP 2012-023664 A JP 2009-218757 A JP 2010-050586 A Japanese Patent Application Laid-Open No. 2011-228921 Japanese Patent No. 4422441 JP 2010-239279 A

  The redundant configuration as described above must be able to quickly restore the active system and resume use after switching to the standby system when a failure occurs in the active system. However, there may be a case where both the active system and the standby system cannot be used simultaneously due to the occurrence of multiple failures. Alternatively, there may be a case where the active system becomes unusable and the standby system operates, a failure occurs again before the active system is restored, and the only active standby system becomes unusable. In particular, when a large-scale disaster such as an earthquake or storm and flood damage occurs, multiple failures such as these are likely to occur.

  In preparation for such multiple failures, it is physically possible to lay a plurality of standby communication channels for one active communication channel, but enormous capital investment is required, Is often difficult.

  Of course, when a multiple failure occurs while a plurality of communication paths are laid, it takes a lot of labor for the network administrator to manually switch to a usable communication path. Even if the search and switching of available communication paths are automated, the "search and switch" requires a time of several seconds to several tens of seconds at the earliest. It cannot be applied to communication methods.

  A technique that can solve the above problems is not described in any of the above-mentioned Patent Documents 1 to 7. The techniques described in Patent Documents 1 to 7 are merely to secure one or a plurality of spare systems and switch from the active system when a failure occurs.

  The object of the present invention is to enable the use of a plurality of standby communication channels at a low cost for one active communication channel, and to quickly switch to the standby system even when multiple failures occur. To provide a communication system, a communication device, a protection switching method, and a switching program that enable continuation.

  In order to achieve the above object, a communication system according to the present invention is a communication system that transmits data between a plurality of communication devices via a plurality of communication paths, and is normally used by the plurality of communication paths. A plurality of protection groups, which are pairs of a standby system that is a communication path used when a failure occurs in the active system that is a communication path and a protection system, are formed, and the active and standby systems of the first protection group When a failure occurs in both systems, the communication apparatus has a function of using the spare system of the second protection group as a temporary replacement of the first protection group.

  In order to achieve the above object, a communication apparatus according to the present invention is a communication apparatus that transmits data to and from other communication apparatuses via a plurality of communication paths, and is a currently used communication path. A storage unit that stores in advance a protection configuration management table including a plurality of sets of protection groups that are a set of protection systems that are communication paths used when a failure occurs in the active system and the active system; and a protection configuration management table A protection management unit for additionally storing a setting for using the second protection group as a temporary alternative when a failure occurs in both the active system and the standby system of the first protection group; A path status monitoring unit that detects whether or not a failure has occurred in the communication path, and other communication paths that can be substituted when a failure occurs in the communication path When the switching determination unit to select and the signal switching means for switching the communication signal to the selected communication path and the switching determination unit has a failure in both the active system and the standby system of the first protection group The standby system of the second protection group is selected as a temporary substitute for the first protection group.

  In order to achieve the above object, a protection switching method according to the present invention is a communication system that transmits data via a plurality of communication paths between a plurality of communication devices, and each of the plurality of communication devices is normally used. A protection configuration management table containing a plurality of settings for a protection group that is a set of protection systems that are communication paths that are used when a failure occurs in the active system and the active system. The protection configuration management table stores in advance settings for using the second protection group as a temporary alternative when a failure occurs in both the active system and the standby system of the first protection group. In addition, the path state monitoring unit detects whether or not a failure has occurred in the active system of the first protection group, When a failure occurs in the active system of the protection group, the switching determination unit instructs the signal switching means to switch the communication signal to the standby system of the first protection group, and at the same time, the path state monitoring unit performs the first operation. Monitoring of whether or not a failure has occurred in the protection system of the protection group is started, and when a failure has occurred in the protection system of the first protection group, the switching determination unit sets the protection system of the second protection group as the first protection system. The signal is switched as a temporary alternative to the protection group, and the signal switching means switches the communication signal to the selected communication path.

  In order to achieve the above object, a protection switching program according to the present invention is a communication system that transmits data through a plurality of communication paths between a plurality of communication devices, and each of the plurality of communication devices is normally used. A protection configuration management table containing a plurality of settings for a protection group that is a set of protection systems that are communication paths that are used when a failure occurs in the active system and the active system. The protection configuration management table stores in advance settings for using the second protection group as a temporary alternative when a failure occurs in both the active system and the standby system of the first protection group. In addition, a failure occurs in the active system of the first protection group in the processor included in the communication device. A procedure for detecting whether or not there is a failure in the active system of the first protection group, a procedure for instructing the signal switching means provided to switch the communication signal to the standby system of the first protection group, At the same time, a procedure for starting monitoring whether or not a failure occurs in the standby system of the first protection group, and when a failure occurs in the standby system of the first protection group, the standby system of the second protection group is A procedure for selecting as a temporary alternative to the first protection group and a procedure for instructing the signal switching means to switch the communication signal to the selected communication path are executed.

  As described above, the present invention uses the backup system of the second protection group as a temporary replacement for the first protection group when a failure occurs in both the active system and the backup system of the first protection group. As a result, it is possible to use a plurality of standby communication channels at a low cost for a single active communication channel, and to quickly switch to the standby system even when multiple failures occur. It is possible to provide a communication system, a communication device, a protection switching method, and a switching program that have the excellent feature of being able to continue the process.

It is explanatory drawing shown about the structure of the communication system which concerns on the 1st Embodiment of this invention. It is explanatory drawing shown about an example of the memory content of the protection configuration management table shown in FIG. 1, and shows about protection groups A and B. FIG. 3 is an explanatory diagram showing an example of storage contents of a protection configuration management table shown in FIG. 1 and shows a state in which a protection group A ′ is additionally stored in addition to the protection groups A and B. It is explanatory drawing shown about the state of each communication path shared by the path | route state monitoring part shown in FIG. 3 is a flowchart illustrating an operation of switching between a protection group A and a protection group A ′ performed by the switching determination unit illustrated in FIG. 1. 6 is a flowchart showing in more detail the operation of determining whether or not the second standby system is available, shown as step S310 in FIG. It is explanatory drawing shown about the structure of the communication system which concerns on the 2nd Embodiment of this invention. It is explanatory drawing shown about an example of each memory content of the protection structure management table of the transmission side apparatus 410 shown in FIG. It is explanatory drawing shown about an example of each memory content of the protection structure management table of the transmission side apparatus 420 shown in FIG. It is explanatory drawing shown about an example of each memory content of the protection structure management table of the transmission side apparatus 430 shown in FIG. It is explanatory drawing shown about an example of each memory content of the protection structure management table of the receiving side apparatus 440 shown in FIG. In the communication system shown in FIG. 7, when a failure occurs in both the active system and the first standby system of the protection group C, which is shown as step S312 in FIG. 5, the communication path is switched to the protection group C ′. It is a flowchart shown about the detail of operation | movement. It is explanatory drawing shown about the structure of the communication system which concerns on the 3rd Embodiment of this invention. It is explanatory drawing shown about an example of the memory content of the protection structure management table of the transmission side apparatus 710 and the receiving side apparatus 720 shown in FIG. It is explanatory drawing shown about an example of the memory content of the protection structure management table of the transmission side apparatus 730 and the reception side apparatus 740 shown in FIG. It is explanatory drawing shown about an example of the memory content of the protection structure management table of the transmission side apparatus 750 and the receiving side apparatus 760 shown in FIG.

(First embodiment)
Hereinafter, the structure of the 1st Embodiment of this invention is demonstrated based on attached FIG.
First, the basic content of the present embodiment will be described, and then more specific content will be described.
The communication system 1 according to the present embodiment is a communication system that transmits data between a plurality of communication apparatuses (transmission side apparatus 10 and reception side apparatus 20) via a plurality of communication paths (transmission paths 31, 32). is there. In this communication system, a plurality of protection groups, which are sets of a standby system that is a communication path used when a failure occurs in the active system and the active system, are formed by a plurality of communication paths. In addition, when a failure occurs in both the active system and the standby system of the first protection group, the communication device uses the backup system of the second protection group as a temporary replacement for the first protection group. It has a function to do. Here, each of the communication devices (the transmission side device 10 and the reception side device 20) stores in advance a protection configuration management table 111 that is a setting for the communication paths used as the active and standby systems of the first and second protection groups. In the stored storage means 11b and the protection configuration management table, a setting for using the second protection group as a temporary alternative when a failure occurs in both the active system and the standby system of the first protection group. A protection management unit 101 that additionally stores, a path state monitoring unit 102 that detects whether or not a failure has occurred in a communication path that is currently in use, and other communication that replaces a failure in the case of a communication path failure A switching determination unit 103 that selects a path, and a signal switching unit 12 that switches a communication signal to the selected communication path. Having.

  In the communication system 1, when a failure occurs in the active system of the first protection group, the switching determination unit 103 instructs the signal switching unit 12 to switch the communication signal to the standby system of the first protection group. At the same time, the path state monitoring unit 102 starts monitoring whether or not a failure has occurred in the standby system of the first protection group. The protection configuration management table 111 stores the priorities of the first and second protection groups in advance, and the switching determination unit 103 has a failure in both the active system and the standby system of the first protection group. If there is only one communication channel that can be used in the second protection group, one of the first and second protection group communication that can use the communication with the higher priority is available. Choose what to do with the channel.

By providing the above configuration, the communication system 1 can use a plurality of standby communication channels at a low cost for one active communication channel, and can be used for a standby system even when multiple failures occur. It is possible to continue communication by switching quickly.
Hereinafter, this will be described in more detail.

  FIG. 1 is an explanatory diagram showing the configuration of the communication system 1 according to the first embodiment of the present invention. The communication system 1 is configured by connecting a transmission side device 10 and a reception side device 20 with a plurality of transmission paths 31 and 32.

  Although the communication system 1 can take the form of bidirectional communication, only one direction is illustrated here for the sake of simplicity of explaining the concept of the present invention. When the method of the present invention is applied to bidirectional communication, a configuration similar to the configuration described below may be provided for both the upstream and downstream directions, or simply by the line shown in FIG. You may make it transmit the signal of both the upstream and downstream directions simultaneously. Further, since the entire network is managed by the host system, it is not included in the scope of the present invention.

  The transmission side device 10 includes a management unit 11 having a configuration as a general computer device, and a signal switching unit 12 that switches a transmission path used for communication. The management unit 11 includes a processor 11a that is a main body that executes a computer program, and a storage unit 11b that stores data.

  The processor 11a functions as each of the protection management unit 101, the path state monitoring unit 102, and the switching determination unit 103 by the operation of the communication management program. Then, the protection configuration management table 111 is stored in the storage unit 11b.

  The protection management unit 101 receives the setting from the higher system and creates the protection configuration management table 111. In addition, a function of receiving transmission path information from the path state monitoring unit 102 and selecting a protection group to be used (in this embodiment, selecting between a protection group A and a protection group A ′ described later), and a protection group A ′ And a function of synchronizing the protection group to be used with the same protection group.

  The path state monitoring unit 102 collects transmission path information of each transmission path included in the apparatus and transmits the transmission path information to the protection management unit 101 and the switching determination unit 103. Here, the transmission path information is quality information such as presence / absence of failure in the transmission path and OAM information. In addition, a mechanism for sharing information on the detected transmission path failure with a path status monitoring unit of another apparatus is provided.

  The switching determination unit 103 receives the information of the protection configuration management table 111 from the protection management unit 101 and the transmission path information from the path state monitoring unit 102, compares the protection configuration management table 111 and the transmission path information, and uses Select the path to be used as the system transmission path.

  The signal switching unit 12 switches the transmission path so that communication is continued on the path selected by the switching determination unit 103. The signal switching unit 12 includes ports 12a and 12b connected to the host system. Each of the transmission lines 31 and 32 includes two communication paths. The transmission path 31 includes communication paths 31a and 31b, and the transmission path 32 includes communication paths 32a and 32b.

  The reception side device 20 also has a configuration equivalent to that of the transmission side device 10 and operates in conjunction with the transmission side device 10. That is, the receiving-side apparatus 20 includes a management unit 21 and a signal switching unit 22, and the management unit 21 includes a processor 21a and a storage unit 21b. The processor 21a functions as each of the protection management unit 201, the path state monitoring unit 202, and the switching determination unit 203, and a protection configuration management table 211 is stored in the storage unit 21b.

  Each of these functions and operations is the same as the element having the same name of the transmission side device 10 and operates in conjunction with the transmission side device 10 side and the reception side device 20 side. Accordingly, in the following description of this specification, only the side of the transmission side apparatus 10 will be described unless particularly necessary. Unless otherwise indicated, the corresponding elements of the receiving device 20 are also configured in the same manner as the transmitting device 10 and operate in conjunction with each other.

  2 and 3 are explanatory diagrams showing an example of the contents stored in the protection configuration management table 111 shown in FIG. FIG. 2 shows the protection groups A and B, and FIG. 3 shows a state in which the protection group A 'is additionally stored.

  The protection configuration management table 111 is created by the protection management unit 101 of the transmission-side apparatus 10 in accordance with a user (network administrator) setting operation, and is stored in the storage unit 11b. Further, the protection management unit 201 of the reception side device 20 also receives the content of the protection configuration management table 111 from the transmission side device 10, and stores the protection configuration management table 211 having the same content in the storage unit 21b. The transmission side apparatus 10 and the reception side apparatus 20 perform signal transmission according to the set configuration.

  The protection groups A and B shown in FIG. 2 (indicated by solid lines in FIG. 1) have a 1 + 1 protection configuration of signals accommodated by the device, including the active system and the standby system, respectively. In other words, the protection configuration management table 111 includes each of the protection group name 111a = “A” and “B” corresponding to the active communication channel number 111b, the standby communication channel number 111c, the protection switching method 111d, and the priority 111e. Contains data items.

  The protection switching method 111d is, for example, ITU-T G. 841, in the case of MPLS-TP, G. This is the method name defined in 8131. The priority 111e is set in advance by the user (network administrator) according to the type and importance of traffic to be transmitted.

  The protection group A ′ additionally stored in FIG. 3 is a “second standby system” when a failure occurs in either or both of the active and standby communication channels of the protection group A. . That is, the protection configuration management table 111 further includes data items such as a working communication channel number 111g, a standby communication channel number 111h, and a protection switching method 111i corresponding to the protection group name 111f = “A ′”.

  In the example shown in FIG. 3, the protection switching method 111i for the protection group name 111f = “A ′” is “1: 1 Uni-Directional / Revertive mode”. This is a 1: 1 configuration that only allows traffic to flow through the standby system.

  The path state monitoring unit 202 of the receiving side apparatus 20 monitors the state of each communication path 31a, 31b, 32a, and 32b from the received signal, and notifies this to the path state monitoring unit 102 of the transmitting side apparatus 10. Share information. This notification may be performed via a management network that is separate from the transmission paths 31 and 32, or may be performed via any communication path included in the transmission paths 31 and 32.

  FIG. 4 is an explanatory diagram showing the state of each communication path shared by the path state monitoring units 102 and 202 shown in FIG. When the status of each communication channel is “normal”, communication is normally performed on the communication channel, and when it is “failure”, it indicates that some failure has occurred on the communication channel. It is.

  FIG. 5 is a flowchart showing the switching operation of the protection group A and the protection group A ′ performed by the switching determination unit 103 shown in FIG. First, the switching determination unit 103 monitors the state of the protection group A including the active system (communication path 31a) and the first standby system (communication path 31b) (step S301). If both the active system and the first standby system are normal, the communication operation on the communication path is continued (step S302). Up to this point, it is within the range of operation of the protection group A, and switching to the protection group A 'is not performed.

  However, if a failure has occurred in both the active system and the first backup system in step S301, it is necessary to switch the protection group from the protection group A to the protection group A '.

  Therefore, the switching determination unit 103 determines whether a failure has occurred in the active system or the first standby system, or a failure has occurred in both, based on the state of each communication channel reported from the path state monitoring unit 102. (Step S303). If a failure has occurred only in the first standby system, the active system is normal, and communication using the active system is selected (step S304). If a failure has occurred only in the active system, the first standby system is normal, and communication using the active system is selected (step S305).

  In both cases of steps S304 and S305, only when the currently used communication path is different from the selected communication path, switching to the selected communication path is performed (step S306). In either case, if a further failure occurs in the selected communication path, communication cannot be continued, and monitoring of the protection group A ′ serving as the second standby system is started by the path state monitoring unit 102. (Step S307).

  If a failure occurs in both the active system and the first standby system in step S303, the communication cannot be continued only with the protection group A. Therefore, the processing immediately proceeds to the processing of the above-described step S307, and the protection group A ′ is monitored. Is started by the path state monitoring unit 102.

  When multiple failures occur in the existing technology, it is common that the network administrator manually changes the communication path or recovers the failure using a protocol for automatically searching for the communication path. However, these methods require several seconds to several tens of seconds at the earliest.

  In contrast, in the present embodiment, when a failure occurs in the active system or the first standby system, the apparatus is kept in a standby state in a state that can be immediately switched to the second standby system. Even if it occurs, it becomes possible to immediately switch to continue communication. In general, switching within “within 50 msec”, which is generally required for transmission systems, is also possible.

  Returning to FIG. 5, even after the monitoring of the protection group A 'is started in step S307, the monitoring of the failure status of the protection group A is continued (step S308). If both the active system and the first standby system are normal, it is determined that the fault that has occurred has been recovered, monitoring of the protection group A ′ is stopped (step S309), and the process returns to step S301. . If a failure has occurred in one of the active system and the first standby system, the “failure that has occurred in one” continues, so that the process proceeds to step S308, that is, to protection groups A and A ′. Continue monitoring.

  If a failure occurs in both the active system and the first standby system in step S308, the switching determination unit 103 determines whether the second standby system is available (step S310, the operation content of the determination is as follows). Later). If available, the communication performed on the communication path used as the second standby system is disconnected only when disconnection is necessary (step S311), and the communication traffic of the protection group A is sent to the communication path (step S312). ). If the second standby system cannot be used in step S310, the signal is disconnected as it is (step S313). Thus, the switching operation of the protection group A and the protection group A ′ is completed.

  FIG. 6 is a flowchart showing in more detail the operation of determining whether or not the second standby system is available, shown as step S310 in FIG. First, the switching determination unit 103 acquires the state of the communication paths 32a and b of the protection group B from the path state monitoring unit 102 (step S351).

  If both the communication paths 32a and 32b are normal in step S351, the unused side (usually the communication path 32a which is the “first standby system” of the protection group B) is set to the second protection group A. As a standby system (step S352), the process proceeds to step S311 (a second standby system is available) in FIG. In this case, the processing for interrupting the communication of the protection group B in step S312 of FIG. 5 is not performed.

  In step S351, if one of the communication paths 32a and 32b is normal and a fault has occurred in the other, the priority 111e of the protection groups A and B is set in the protection configuration management table 111 shown in FIG. Compare (step S353).

  If the protection group A has a higher priority 111e, the communication of the protection group A should continue even if the communication of the protection group B is interrupted. The communication path 32a) which is the “active system” of the protection group B is set as the second standby system of the protection group A (step S354), and the process proceeds to the process of step S311 (the second standby system is available) in FIG. In this case, processing for interrupting communication of the protection group B is performed in step S312 of FIG.

  When both the communication paths 32a and b are abnormal in step S351, and when the priority 111e of the protection group B is higher (or the priority 111e of the protection groups A and B is equal) in step S353, both The process proceeds to step S313 in FIG. 5 (the second standby system cannot be used).

  Note that switching to the second standby system is only used as a “temporary substitute” for the transmission path, so that either one of the faults occurring in the communication paths 31a and b of the protection group A is recovered. In such a case, it is desirable to return to communication using the restored side of the communication paths 31a and 31b.

(Overall operation of the first embodiment)
Next, the overall operation of the above embodiment will be described.
The protection switching method according to the present embodiment is a communication system that transmits data via a plurality of communication paths between a plurality of communication apparatuses, and each of the plurality of communication apparatuses is a communication path that is normally used. A protection configuration management table that stores in advance a plurality of sets of protection groups that are pairs of protection systems that are communication paths used when a failure occurs in the active system and the active system. This protection configuration management table In addition, when a failure occurs in both the active system and the standby system of the first protection group, a setting for using the second protection group as a temporary alternative is stored in advance, and the first protection The path state monitoring unit detects whether a failure has occurred in the active system of the group (step S301 in FIG. 5). 302), when a failure occurs in the active system of the first protection group, the switching determination unit instructs the signal switching means to switch the communication signal to the standby system of the first protection group (FIG. 5, Steps S303 to S303). 306) At the same time, the path status monitoring unit starts monitoring whether or not a failure has occurred in the standby system of the first protection group (step S307 in FIG. 5), and the standby system of the first protection group has failed. When this occurs, the switching determination unit selects an available communication path from the second protection group as a temporary alternative to the first protection group (step S308 in FIG. 5), and the signal switching means is selected. The communication signal is switched to the communication path (FIG. 5, steps S311 to S312).

Here, each of the above operation steps may be programmed so as to be executable by a computer, and these may be executed by the processors 11a and 21a of the communication apparatus that directly executes the respective steps. The program may be recorded on a non-temporary recording medium, such as a DVD, a CD, or a flash memory. In this case, the program is read from the recording medium by a computer and executed.
By this operation, this embodiment has the following effects.

  When the first and second protection groups exist, the standby system of the second protection group is used even if a failure occurs in the active system of the first protection group and the communication is switched to the standby system. Often, it is in a state of playing without According to the present embodiment, such a protection system of the second protection group can be temporarily used as a “second protection system of the first protection group”, and the current use of the first protection group due to multiple failures. Both the system and the first standby system can be used for relief when the system becomes unavailable.

  At that time, when a failure occurs in the active system of the first protection group and the system is switched to the standby system, the use of the second standby system is prepared. Even in a connection-type communication method in which communication must not be interrupted, it is possible to ensure highly reliable communication continuity.

  In the event that both the primary protection system and the primary protection system of the first protection group become unavailable, and there is a case where only the second protection group can be used, the first and second protection groups Since the priority is compared between the protection groups and the higher priority communication is performed by the remaining one system, the double failure is more accurately remedied while allowing limited facilities (especially communication channels). It becomes possible to do.

(Second Embodiment)
The second embodiment of the present invention is configured by a plurality of transmission side devices. Even in such a case, the same operation as in the first embodiment is possible.
Hereinafter, this will be described in more detail.

  FIG. 7 is an explanatory diagram showing the configuration of the communication system 401 according to the second embodiment of the present invention. The communication system 401 is configured by connecting transmission-side devices 410, 420, and 430 and a reception-side device 440 through a plurality of transmission lines 451, 452, 453, and 454.

  The communication system 401 operates in the same manner as the communication system 1 of the first embodiment described above. However, the transmission side apparatus 10 that is only one in the first embodiment has a plurality of transmission side apparatuses 10 in the second embodiment. It is divided into transmission side devices 410, 420, and 430.

  Each of these transmission side devices 410, 420, and 430 includes a management unit and a signal switching unit similar to those in the first embodiment described above. The transmission side device 410 includes a management unit and a signal switching unit 412, the transmission side device 420 includes a management unit and a signal switching unit 422, and the transmission side device 430 includes a management unit and a signal switching unit 432.

  The management unit of the transmission side apparatus 410 includes a processor and a storage unit. The processor functions as each of the protection management unit 511, the path state monitoring unit 512, and the switching determination unit 513 by the operation of the communication management program. In the storage means, a protection configuration management table 514 is stored. The functions of these elements conform to the elements having the same names as those in the first embodiment. FIG. 7 does not describe management means, a processor, storage means, and a protection configuration management table to avoid complications.

  The management unit of the transmission side device 420 includes a processor and a storage unit. The processor functions as each of the protection management unit 521, the path state monitoring unit 522, and the switching determination unit 523 by the operation of the communication management program. In the storage means, a protection configuration management table 524 is stored.

  The management unit of the transmission side device 430 includes a processor and a storage unit. The processor functions as each of the protection management unit 531 and the switching determination unit 523 by the operation of the communication management program. In the storage means, a protection configuration management table 534 is stored. Although a path state monitoring unit may exist in the transmission side device 430, it is not shown in FIG. 7 because it is not involved in the operation of this embodiment.

  The reception side device 440 includes a management unit and a signal switching unit 442. The management unit 441 of the reception side device 440 includes a processor and a storage unit. The processor functions as each of the protection management unit 541, the path state monitoring unit 542, and the switching determination unit 543 by the operation of the communication management program. In the storage means, a protection configuration management table 544 is stored.

  The transmission path 451 connects the transmission side devices 410 and 420. The transmission line 452 connects the transmission side devices 410 and 430. The transmission path 453 connects the transmission side apparatus 420 and the reception side apparatus 440, and includes two systems of communication paths 453a and 453b. The transmission path 454 connects the transmission side apparatus 430 and the reception side apparatus 440, and includes two systems of communication paths 454a and 454b.

  The signal switching unit 412 of the transmission side device 410 has a port of only one system. The signal switching means 442 of the reception side device 440 has two ports and is connected to the host system.

  The transmission side devices 410, 420, and 430 and the reception side device 440 are connected to the transmission lines 451, 452, 453, and 454 via a management network that is separate from the transmission lines 451, 452, 453, and 454, respectively. Exchange information about switching.

  8 to 11 are explanatory diagrams showing an example of storage contents of each of the protection configuration management tables 514, 524, 534, and 544 of the transmission side devices 410, 420, and 430 and the reception side device 440 shown in FIG. is there. These protection configuration management tables 514, 524, 534 and 544 are created and stored in cooperation by the protection management units 511, 521, 531 and 541 of the respective devices. The data items included in the respective protection configuration management tables 514, 524, 534, and 544 conform to the case of the first embodiment shown in FIGS.

  As the protection group C, a route of the transmission side device 410-transmission path 451-transmission side device 420-transmission path 453-reception side device 440 is set. Here, of the transmission paths 453, the communication path 453a is set as the active system, and the communication path 453b is set as the first standby system. Further, as the protection group D, a route of the transmission side device 410 -transmission path 452 -transmission side device 430 -transmission path 454 -reception side device 440 is set. Here, of the transmission paths 454, the communication path 454a is set as the active system, and the communication path 454b is set as the first standby system.

  Then, the protection group C ′ is set as a “second standby system” when a failure occurs in either or both of the active and standby communication paths of the protection group C. The protection group C ′ passes through a free path in the protection group D.

  The setting contents of the above protection groups C, D, and C ′ are in accordance with the setting contents of the protection groups A, B, and A ′ in the first embodiment. However, each device holds only the settings for the protection group in which its own device is involved as its own protection configuration management table.

  That is, the protection configuration management table 514 stores only the settings of the protection group C ′, the protection configuration management table 524 stores the protection groups C and C ′, and the protection configuration management table 534 stores only the settings of the protection groups D and C ′. . Incidentally, the protection configuration management table 544 stores all settings of the protection groups C, D, and C ′.

  In other words, each device belonging to the protection group C ′ recognizes that each device belongs to the protection group C ′ by setting the protection configuration management table for each device in advance by the network administrator. ing.

  Based on the above assumption, the communication system 401 performs the same operation as that of the first embodiment, that is, the operation shown as the flowcharts of FIGS. However, a plurality of devices need to be involved when switching communication paths. The operation performed at that time will be described.

  FIG. 12 is a communication system 401 shown in FIG. 7 and communicates to the protection group C ′ when a failure occurs in both the active system and the first backup system of the protection group C shown as step S312 in FIG. It is a flowchart shown about the detail of operation | movement at the time of switching a path | route. As can be seen from FIGS. 8 and 10, the transmission side devices 410 and 430 do not participate in the protection group C. However, in order to switch the communication of the protection group C to the protection group C ′, the transmission side devices 410 and 430 need to be involved.

  Therefore, the switching determination unit 523 of the transmission-side device 420 that is a main body that switches the communication path determines whether the protection group can be switched to the switching determination units 513, 533, and 543 of other devices. First, an inquiry is made (step S601). The switching determination units 513, 533, and 543 of each device that received the inquiry each return a switchable response (step S602).

  The switching determination unit 523 waits for a switchable response from all other devices (step S603), and then transmits a protection group switching trigger to each device (step S604). The switching determination units 513, 533, and 543 of each device that have received this switching trigger each perform switching of communication paths (step S605), and then return a response indicating completion of switching (step S606).

  In addition, the switching determination unit 543 of the reception-side device 440 operating in cooperation with the switching determination unit 523 of the transmission-side device 420 may be the main body of the operations in steps S601, 603, and 604.

  By providing such a mechanism, even when a plurality of devices need to be involved at the time of switching communication paths, the same operation as the flowchart shown in FIGS. It becomes possible. Further, even when the transmission side device 420 fails, the communication can be continued by switching the communication path to the protection group C ′. Of course, when the transmission lines that are the active system and the first standby system of the protection group C are restored, the communication path may be returned from the protection group C ′ to the protection group C.

  In the configuration of the communication system 401 illustrated in FIG. 7, communication cannot be continued if the reception-side device 440 fails. In order to avoid such a situation, the receiving side can be configured by a plurality of devices in the same manner as the transmitting side. The operation in that case also conforms to this embodiment.

(Third embodiment)
The third embodiment of the present invention includes a plurality of transmission side devices and reception side devices. Even in such a case, the same operation as in the first embodiment is possible.
Hereinafter, this will be described in more detail.

  FIG. 13 is an explanatory diagram showing the configuration of a communication system 701 according to the third embodiment of the present invention. The communication system 701 is configured by connecting transmission-side devices 710, 730, and 750 and reception-side devices 720, 740, and 760 with a plurality of transmission lines 771, 772, 773, 774, and 775.

  The transmission side devices 710, 730, and 750 and the reception side devices 720, 740, and 760 are all provided with management means and signal switching means similar to those in the first and second embodiments described above. Each management unit includes a processor and a storage unit. The processor functions as each of a protection management unit, a path state monitoring unit, and a switching determination unit by the operation of the communication management program. A storage configuration management table is stored in the storage means. FIG. 13 does not describe management means, a processor, storage means, and a protection configuration management table to avoid complications.

  The transmission side device 710 includes a signal switching unit 712, a protection management unit 811, a path state monitoring unit 812, a switching determination unit 813, and a protection configuration management table 814. Each remaining device, each means included in the receiving device 720 is in the 820s, each device included in the transmitting device 730 is in the 830s, each device included in the receiving device 740 is in the 840s, and each device included in the transmitting device 750 is 850. Each unit included in the platform and the receiving side device 760 is referred to as a reference number in the 860s.

  The transmission path 771 connects the transmission side device 710 and the reception side device 720, and includes two systems of communication paths 771a and 771b. The transmission line 772 connects the transmission side devices 710 and 730. The transmission path 773 connects the transmission side devices 730 and 750. The transmission line 774 connects the receiving side devices 720 and 740. The transmission path 775 connects the receiving side devices 740 and 760. The transmission line 776 connects the transmission side device 750 and the reception side device 760. The transmission path 777 connects the transmission side device 730 and the reception side device 740.

  Further, the transmission side devices 710, 730, and 750 and the reception side devices 720, 740, and 760 are respectively connected to the transmission lines 771 to 776 via a separate management network, and the protection configuration and communication that will be described later are communicated. Information related to route switching is exchanged.

  14 to 16 show the protection configuration management tables 814, 834, 854 and 824, 844, 864 of the transmission side devices 710, 730 and 750 and the reception side devices 720, 740 and 760 shown in FIG. It is explanatory drawing shown about an example of the memory content. 14 shows protection configuration management tables 814 and 824 of the transmission side device 710 and reception side device 720, FIG. 15 shows protection configuration management tables 834 and 844 of the transmission side device 730 and reception side device 740, and FIG. The protection configuration management tables 854 and 864 of the receiving side device 760 are respectively shown.

  As the protection group E, a path from the transmission side device 710 to the transmission path 771 to the reception side device 720 is set. Here, of the transmission paths 771, the communication path 771a is set as the active system, and the communication path 771b is set as the first standby system. Further, as the protection group F, the transmission side device 750-transmission path 766-reception side device 760 is the active system, and the transmission side device 750-transmission path 766-reception side device 760 is the active system. 750-transmission path 773-transmission side apparatus 730-transmission path 777-reception side apparatus 740-transmission path 775-reception side apparatus 760 is set as the first backup system.

  Then, the protection group E ′ is set as a “second standby system” when a failure occurs in either or either of the active and standby communication channels of the protection group E. This protection group E ′ is a path of a transmission side device 710 -transmission path 772 -transmission side apparatus 730 -transmission path 777 -reception side apparatus 740 -transmission path 774 -reception side apparatus 720. Each device belonging to the protection group E ′ recognizes that it belongs to the protection group E ′ by setting the protection configuration management table.

  In the transmission-side device 710, a signal input from the host system is branched into three and is sent to each of the communication path 771a, the communication path 771b, and the transmission path 772. When both or one of the working and protection communication paths of the protection group E is normal, the signal sent to the transmission path 772 is discarded by the transmission side apparatus 730 or the reception side apparatus 740.

  The operation for switching the communication path from the protection group E to E ′ is almost the same as that shown in FIG. 12, but the object to be inquired as to whether or not switching is possible in step S601 is the protection group E ′. The transmission side devices 710 and 730 and the reception side devices 720 and 740 belong thereto. The transmission side device 750 and the reception side device 760 are not involved in the protection group E ′, and even if these devices are not involved, the protection group E to E ′ can be switched. Don't be. The operation other than this point is the same as that of the second embodiment shown in FIG.

(Extended embodiment)
As described in the second and third embodiments above, in the case where a plurality of communication devices need to be involved in switching the communication system, it is determined whether or not the protection group can be switched to the necessary devices. The switching trigger may be transmitted after inquiring and obtaining a switchable reply from all the target devices. This is the same even if the number of systems of communication paths and the number of communication devices are increased and the configuration of communication paths is further complicated.

  The present invention has been described with reference to the specific embodiments shown in the drawings. However, the present invention is not limited to the embodiments shown in the drawings, and any known hitherto provided that the effects of the present invention are achieved. Even if it is a structure, it is employable.

  Regarding the embodiment described above, the main points of the new technical contents are summarized as follows. In addition, although part or all of the said embodiment is summarized as follows as a novel technique, this invention is not necessarily limited to this.

(Supplementary note 1) A communication system for transmitting data between a plurality of communication devices via a plurality of communication paths,
The plurality of communication paths form a plurality of protection groups that are a set of a working system that is normally used and a protection system that is a communication path that is used when a failure occurs in the working system. With
When a failure occurs in both the active system and the standby system of the first protection group, the communication device uses the backup system of the second protection group as a temporary replacement for the first protection group. A communication system characterized by having a function.

(Appendix 2) Each of the plurality of communication devices is
Storage means for preliminarily storing a protection configuration management table that is a setting for communication paths used as an active system and a standby system of the first and second protection groups;
Protection that additionally stores settings for using the second protection group as a temporary alternative when a failure occurs in both the active system and the standby system of the first protection group in the protection configuration management table The management department,
A path state monitoring unit for detecting whether a failure has occurred in the communication path currently in use;
When a failure occurs in the communication path, a switching determination unit that selects another communication path as an alternative to the failure,
The communication system according to appendix 1, further comprising signal switching means for switching a communication signal to the selected communication path.

(Supplementary Note 3) When a failure occurs in the active system of the first protection group, the switching determination unit instructs the signal switching unit to switch the communication signal to the standby system of the first protection group, The communication system according to appendix 2, wherein the path state monitoring unit starts monitoring whether or not a failure has occurred in the standby system of the first protection group.

(Supplementary Note 4) The protection configuration management table stores the priorities of the first and second protection groups in advance,
When the switching determination unit has a failure in both the active system and the standby system of the first protection group, and there is only one communication path that can be used in the second protection group, the switching determination unit The communication according to claim 2, wherein the communication having the higher priority among the communication of the first and second protection groups is selected to be performed using the one available communication path. system.

(Supplementary Note 5) A communication device that transmits data to and from other communication devices via a plurality of communication paths,
A protection configuration management table including a plurality of settings for a protection group that is a set of a protection system that is a set of a standby system that is a communication path that is used when a failure occurs in the active system that is normally used and the active system is stored in advance. Storage means
Protection that additionally stores settings for using the second protection group as a temporary alternative when a failure occurs in both the active system and the standby system of the first protection group in the protection configuration management table The management department,
A path state monitoring unit for detecting whether a failure has occurred in the communication path currently in use;
When a failure occurs in the communication path, a switching determination unit that selects another communication path as an alternative to the failure,
And a signal switching means for switching a communication signal to the selected communication path,
The switching determination unit selects a standby system of the second protection group as a temporary replacement for the first protection group when a failure occurs in both the active system and the standby system of the first protection group. A communication device characterized by:

(Supplementary Note 6) In a communication system for transmitting data between a plurality of communication devices via a plurality of communication paths,
Each of the plurality of communication devices has a plurality of settings for a protection group that is a set of a working system that is a communication path that is normally used and a protection system that is a communication path that is used when a failure occurs in the working system. Including a protection configuration management table including
In this protection configuration management table, a setting for using the second protection group as a temporary alternative when a failure occurs in both the active system and the standby system of the first protection group is stored in advance. And
A path state monitoring unit detects whether a failure has occurred in the active system of the first protection group,
When a failure occurs in the active system of the first protection group, the switching determination unit instructs the signal switching means to switch the communication signal to the standby system of the first protection group,
At the same time, the path status monitoring unit starts monitoring whether a failure has occurred in the standby system of the first protection group,
When a failure occurs in the protection system of the first protection group, the switching determination unit selects the protection system of the second protection group as a temporary replacement of the first protection group;
A protection switching method, wherein the signal switching means switches a communication signal to the selected communication path.

(Supplementary note 7) In a communication system for transmitting data between a plurality of communication devices via a plurality of communication paths,
Each of the plurality of communication devices has a plurality of settings for a protection group that is a set of a working system that is a communication path that is normally used and a protection system that is a communication path that is used when a failure occurs in the working system. Including a protection configuration management table including
In this protection configuration management table, a setting for using the second protection group as a temporary alternative when a failure occurs in both the active system and the standby system of the first protection group is stored in advance. And
A processor included in the communication device;
A procedure for detecting whether a failure has occurred in the active system of the first protection group;
A procedure for instructing the signal switching means provided to switch the communication signal to the standby system of the first protection group when a failure occurs in the active system of the first protection group;
At the same time, a procedure for starting monitoring whether or not a failure has occurred in the standby system of the first protection group,
A step of selecting a backup system of the second protection group as a temporary replacement of the first protection group when a failure occurs in the backup system of the first protection group;
And a protection switching program for causing the signal switching means to execute a command to switch the communication signal to the selected communication path.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2012-184807 for which it applied on August 24, 2012, and takes in those the indications of all here.

  The present invention can be widely applied in data communication systems. In particular, it is suitable for connection-type communication as described above and suitable for MAN (Metro Area Network) that requires high-speed and large-capacity communication.

1, 401, 701 Communication system 10, 410, 420, 430, 710, 730, 750 Transmission side device 11, 21 Management means 11a, 21a Processor 11b, 21b Storage means 12, 22, 412, 422, 432, 442, 712 Signal switching means 20, 440, 720, 740, 760 Reception side devices 31, 32, 451, 452, 453, 454, 771, 772, 773, 774, 775, 776, 777 Transmission paths 31a, 31b, 32a, 32b, 453a, 453b, 454a, 454b Communication path 101, 201, 511, 521, 531, 541, 811 Protection management unit 102, 202, 512, 522, 542, 812 Path state monitoring unit 103, 203, 513, 523, 533, 543, 813 switching determination unit 11,211,514,524,534,544,814,824,834,844,854,864 protection configuration management table

Claims (7)

A communication system that transmits data through a plurality of communication paths between a plurality of communication devices,
The plurality of communication paths form a plurality of protection groups that are a set of a working system that is normally used and a protection system that is a communication path that is used when a failure occurs in the working system. With
When a failure occurs in both the active system and the standby system of the first protection group, the communication device uses the backup system of the second protection group as a temporary replacement for the first protection group. A communication system characterized by having a function. Each of the plurality of communication devices;
Storage means for preliminarily storing a protection configuration management table that is a setting for communication paths used as an active system and a standby system of the first and second protection groups;
Protection that additionally stores settings for using the second protection group as a temporary alternative when a failure occurs in both the active system and the standby system of the first protection group in the protection configuration management table The management department,
A path state monitoring unit for detecting whether a failure has occurred in the communication path currently in use;
When a failure occurs in the communication path, a switching determination unit that selects another communication path as an alternative to the failure,
The communication system according to claim 1, further comprising: a signal switching unit that switches a communication signal to the selected communication path. When a failure occurs in the active system of the first protection group, the switching determination unit instructs the signal switching means to switch the communication signal to the standby system of the first protection group, and at the same time, the route state monitoring The communication system according to claim 2, wherein the unit starts monitoring whether or not a failure has occurred in the standby system of the first protection group. The protection configuration management table stores the priorities of the first and second protection groups in advance;
When the switching determination unit has a failure in both the active system and the standby system of the first protection group, and there is only one communication path that can be used in the second protection group, the switching determination unit The communication apparatus according to claim 2, wherein the higher priority communication among the communication of the first protection group and the second protection group is selected to be performed using the one available communication path. Communications system. A communication device that transmits data to and from other communication devices via a plurality of communication paths,
A protection configuration management table including a plurality of settings for a protection group that is a set of a protection system that is a set of a standby system that is a communication path that is used when a failure occurs in the active system that is normally used and the active system is stored in advance. Storage means
Protection that additionally stores settings for using the second protection group as a temporary alternative when a failure occurs in both the active system and the standby system of the first protection group in the protection configuration management table The management department,
A path state monitoring unit for detecting whether a failure has occurred in the communication path currently in use;
When a failure occurs in the communication path, a switching determination unit that selects another communication path as an alternative to the failure,
And a signal switching means for switching a communication signal to the selected communication path,
The switching determination unit selects a standby system of the second protection group as a temporary replacement for the first protection group when a failure occurs in both the active system and the standby system of the first protection group. A communication device characterized by: In a communication system that transmits data via a plurality of communication paths between a plurality of communication devices,
Each of the plurality of communication devices has a plurality of settings for a protection group that is a set of a working system that is a communication path that is normally used and a protection system that is a communication path that is used when a failure occurs in the working system. Including a protection configuration management table including
In this protection configuration management table, a setting for using the second protection group as a temporary alternative when a failure occurs in both the active system and the standby system of the first protection group is stored in advance. And
A path state monitoring unit detects whether a failure has occurred in the active system of the first protection group,
When a failure occurs in the active system of the first protection group, the switching determination unit instructs the signal switching means to switch the communication signal to the standby system of the first protection group,
At the same time, the path status monitoring unit starts monitoring whether a failure has occurred in the standby system of the first protection group,
When a failure occurs in the protection system of the first protection group, the switching determination unit selects the protection system of the second protection group as a temporary replacement of the first protection group;
A protection switching method, wherein the signal switching means switches a communication signal to the selected communication path. In a communication system that transmits data via a plurality of communication paths between a plurality of communication devices,
Each of the plurality of communication devices has a plurality of settings for a protection group that is a set of a working system that is a communication path that is normally used and a protection system that is a communication path that is used when a failure occurs in the working system. Including a protection configuration management table including
In this protection configuration management table, a setting for using the second protection group as a temporary alternative when a failure occurs in both the active system and the standby system of the first protection group is stored in advance. And
A processor included in the communication device;
A procedure for detecting whether a failure has occurred in the active system of the first protection group;
A procedure for instructing the signal switching means provided to switch the communication signal to the standby system of the first protection group when a failure occurs in the active system of the first protection group;
At the same time, a procedure for starting monitoring whether or not a failure has occurred in the standby system of the first protection group,
A step of selecting a backup system of the second protection group as a temporary replacement of the first protection group when a failure occurs in the backup system of the first protection group;
And a protection switching program for causing the signal switching means to execute a command to switch the communication signal to the selected communication path.

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