JP5041677B2 - Add / drop multiplexer terminal equipment - Google Patents

Description

  The present invention relates to an add / drop multiplexer terminal device used in a transmission apparatus constituting a backbone communication network. In particular, the present invention relates to an add / drop type multiplexing terminal station device used in a unidirectional path switched ring system (UPSR) that performs switching in units of transmission paths.

  As the conventional telephone-based communication network shifts to a computer-centric multimedia communication network, the amount of data to be handled has increased and the requirements for basic communication for each service have also changed. With regard to the redundant configuration, it is desired not to simply have a redundant configuration as in the prior art but to use these redundant configurations flexibly. In particular, in order to give priority to economy, it is necessary to provide a redundant configuration such as providing a transmission path without a redundant configuration, or providing a transmission path that does not require a redundant configuration because the upper layer of the transmission path already has a redundant configuration. There is no need for a transmission path.

  In the add / drop multiplexer terminal device described in Patent Document 1, in order to solve the problem that communication is interrupted when a failure occurs in the conventional extra traffic, each of the high-speed interface unit, the in-device redundant unit, and the low-speed interface unit By fixing the connection relationship, a backup open transmission path is provided.

  By the way, UPSR is a typical ring system having a redundant configuration for each transmission path. This is a ring system in which an add / drop multiplexer (ADM) is placed in a ring and transfers in a single direction (clockwise, counterclockwise) while branching / inserting or through-connecting transmission paths. .

  FIG. 4 shows a general configuration of an ADM in a normal UPSR. In the figure, each of the ADMs 1, 2, 3 arranged in the ring has a high-speed interface having two types of high-speed interfaces corresponding to a clockwise route (0 system: CW) and a counterclockwise route (1 system: CCW). (HSIF) 11-0, 11-1, branch insertion units 12-0, 12- having 1 + 1 intra-device redundancy for performing redundancy switching in the event of a device failure and performing through-connection or branch insertion of transmission paths 1. Low-speed interface units (LSIF) 13-0 and 13-1 having a 1 + 1 redundant configuration for performing redundancy switching with a low-speed transmission / reception device. The high-speed interface unit 11 and the branch insertion unit 12 have a 1: 1 connection relationship such that the 0 system is 0 system and the 1 system is 1 system. The connection relationship is a tangled connection.

  When all the 0 systems are operating as active, the transmission paths that are added and dropped by the ADM send a signal from the 0 system low speed interface unit 13-0 to the 0 system add / drop unit 12-0, and further, the 0 system Is sent to the high-speed interface unit 11-0 and sent into the ring through a clockwise (CW) route. On the other hand, the 1-system branch / insertion unit 12-1 receives a signal from the 0-system low-speed interface unit 13-0 and sends the signal to the 1-system high-speed interface unit 11-1, and a counterclockwise (CCW) path as a redundant signal. To send it into the ring. The operation on the receiving side is the same.

  In the configuration of FIG. 4, there is no redundant configuration between the high-speed interface unit 11 and the branch insertion unit 12, but normally, a failure of the branch insertion unit 12 is similar to a failure of the high-speed interface unit 11 and is transmitted within the ring. It is relieved by operating an intra-ring path switching function that operates in the event of a road failure. Specifically, the low-speed interface unit 13 grasps transmission path signal states from the 0-system and 1-system branch insertion units 12-0 and 12-1, and operates the signal reception selector in the low-speed interface unit 13. Rescue by switching to a normal system (reception end switching function for transmission path).

FIG. 5 shows a standby system open configuration when an ADM is used in a normal UPSR. In the figure, the connection states of the low-speed interface units 13-0 and 13-1 and the branch insertion units 12-0 and 12-1 are fixed connections in the 0 system and the 1 system, respectively. As a result, using the intra-ring path switching function and the intra-device redundancy function, it is possible to open the protection system for any transmission path and provide two active transmission paths (protection system open path).
JP 11-27281 A

  FIG. 6 shows the spillover state of the fault in the ring when the standby system is opened when the ADM is used in the normal UPSR. When a package of the ADM high-speed interface unit 11, the add / drop unit 12, or the low-speed interface unit 13 breaks down, the signal of the backup system open path accommodated by them is simply cut off. On the other hand, when a failure occurs in the transmission line connected to the high speed side in the ring or in the ADM 2 other than the ADM that performs branch insertion, as shown in FIG. 6, it is transmitted from the low speed interface unit 13-0 of the ADM 1 to the opposite device 21. And the signal transmitted from the low-speed interface unit 13-1 of the ADM 3 to the opposite device 23 are cut off.

  The case where the standby system is released includes a case in which an economical transmission path that does not require redundancy is provided and a case in which a redundant configuration is already established in the upper layer on the opposite device side connected to the low-speed side of the ADM. In some cases, the ADM does not require a redundant configuration in order to avoid the increase in the frequency. As an example of the latter case, for example, when duplication is already configured in an ATM VP that is an upper layer of the SDH layer, it is not necessary to have a redundant configuration in the SDH VC path (transmission path in this specification), The two working transmission paths (in this case, two SDH VC paths) that accommodate the two ATM VPs are transferred through the backbone network.

  Therefore, consider a case where two transmission paths already redundant in the upper layer as described above are accommodated. In other words, in FIG. 6, transmission paths (for example, SDH VC paths) are assigned to redundant signals (VP (0), VP (1) in the figure) in the upper layer in the opposing devices 21, 23 having the upper layer, respectively, and ADM1, 3 Assume a situation where a low-speed interface unit is connected.

  In this case, redundant signals in the upper layer are connected to the 0-system and 1-system of the low-speed interface unit of the ADMs 1 and 3, respectively. Therefore, when a failure occurs in the ring, the VP (0) signal to the opposing device 21 and the VP (1) signal to the opposing device 23 are cut off, and when viewed in the upper layer layer, each of the 0-system signal and the 1-system signal. One-way line is broken. Normally, when taking a redundant configuration, a system in which no failure has occurred needs to be normal in both the upstream and downstream directions. When the above case occurs, the opposing devices 21 and 23 having higher layers have a redundant configuration. Can not keep. Although not shown in FIG. 6, the same applies when two transmission paths having redundancy in the upper layer are connected to the 0 system of the low-speed interface unit of the ADM and the 0 system of the low-speed interface unit of the other ADM. Each line of the signal and the 1-system signal is cut off, and a redundant configuration cannot be maintained.

  The present invention provides an add / drop multiplexer having a standby release function capable of transferring without damaging the redundancy function when a failure occurs in the ring even when accommodating two transmission paths already redundant in the upper layer. An object is to provide a station apparatus (ADM).

The present invention is used in a unidirectional path switching ring system (UPSR) that is a ring switching system, and is used between a high-speed interface unit that switches between two types of clockwise and counterclockwise rings, and a low-speed counter device. and a low-speed interface unit having in redundant switching 1 + 1 redundant configuration for performing, located between the high-speed interface unit and the low-speed interface unit, having a 1 + 1 redundant configuration for redundant switching when the equipment, the transmission path unit in branch insertable multiplexing terminal station device provided in a drop unit for performing an add-drop, high-speed interface unit includes a high-speed interface portion of the 0-system received by the counterclockwise transmitted in clockwise, in counterclockwise a high-speed interface portion of the 1-system received by the transmitted clockwise, slow interface and drop unit is connected type 1 + 1 redundant configuration for redundancy switching And the first working transmission path output from the 0-system low-speed interface unit is connected to the 0-system branch / insertion unit, and the second working transmission path output from the 1-system low-speed interface unit is set to 1. The first active transmission path connected to the system branch insertion unit and output from the system 0 branch insertion unit is connected to the system 0 low speed interface unit, and the second output from the system 1 branch insertion unit is output. the signal reception selector corresponding to the connection form of the standby opening connecting the active transmission path to the low-speed interface unit 1 system is including configuration, signal reception selector and the drop unit of the low-speed interface units corresponding to any of the transmission path manipulating the signal reception selector switch setting for the first and second two active transmission path by redundancy switching path or the protection system open (spare system open path) with respect to any transmission path Comprising a 備系 opening control unit.

  A branch and insert type multiplexing terminal station (ADM) of the present invention includes a high-speed interface unit that transmits clockwise and receives counterclockwise, and a high-speed interface unit that transmits counterclockwise and receives clockwise. By realizing a transmission path with no transmission (protection system open path) as a ring system, even when two transmission path signals already redundant in the upper layer are accommodated by ADM, it is redundant even when a failure occurs in the ring. It is possible to realize a standby system release function that can transfer without losing the configuration.

  FIG. 1 shows an embodiment of the ADM of the present invention. In the figure, the high-speed interface units (HSIF) 11-0 and 11-1, the add / drop units 12-0 and 12-1, and the low-speed interface units (LSIF) 13-0 of the ADMs 1, 2, and 3 arranged in the ring. , 13-1 is the same as the conventional apparatus. A feature of the present invention is that the high-speed interface unit 11-0 is configured to transmit clockwise and receive counterclockwise, and the high-speed interface unit 11-1 is configured to transmit counterclockwise and receive clockwise. .

  Note that the connection relationship between the add / drop unit 12 and the low-speed interface unit 13 is a tangled connection. Although not shown, the low-speed interface unit 13 and the branch insertion unit 12 receive the output signal of the 0-system low-speed interface unit 13-0 by the 0-system branch insertion unit 12-0 in addition to the normal redundancy switching connection relationship. The output signal of the 1-system low-speed interface unit 13-1 is received by the 1-system branch insertion unit 12-1, and the output signal of the 0-system branch insertion unit 12-0 is received by the 0-system low-speed interface unit 13-0. And a signal reception selector configured to receive the output signal of the 1-system branch insertion unit 12-1 by the 1-system low-speed interface unit 13-1.

  The standby system release control unit 15 operates the signal reception selectors of the low-speed interface unit 13 and the add / drop unit 12 corresponding to an arbitrary transmission path, and sets a normal redundant switching path or a standby system open path for the arbitrary transmission path. In this configuration, the setting to be switched is switched, and the standby system release control is performed for an arbitrary transmission path.

  FIG. 2 shows a configuration example of the ADM when the standby system is opened. The connection relationship between the high-speed interface unit 11 and the branch insertion unit 12 and between the branch insertion unit 12 and the low-speed interface unit 13 is the same as when the standby system of the UPSR in FIG. 5 is opened. A signal input from the low-speed interface unit 13-0 of the ADM 1 is processed by the add / drop unit 12-0 and the high-speed interface unit 11-0, and then transmitted to the clockwise route (CW). The high-speed interface unit 11-0 of the ADM 3 receives the signal from the high-speed interface unit 11-0 of the ADM 1 and sends it out to the add / drop unit 12-0. The signal from the add / drop unit 12-0 is sent to the opposite device 23 of the ADM 3 via the low speed interface unit 13-0.

  Similarly, a signal transmitted from ADM 3 to ADM 1 is processed by the low-speed interface unit 13-0, the branch insertion unit 12-0, and the high-speed interface unit 11-0 of ADM 3 and then sent to the counterclockwise route (CCW). Is done. The high-speed interface unit 11-0 of the ADM 1 receives a signal from the high-speed interface unit 11-0 of the ADM 3, and sends it to the opposite device 21 of the ADM 1 via the branch insertion unit 12-0 and the low-speed interface unit 13-0. .

  Similarly, the signal from the low-speed interface unit 13-1 of ADM1 to the low-speed interface unit 13-1 of ADM3 and the signal from the low-speed interface unit 13-1 of ADM3 to the low-speed interface unit 13-1 of ADM1 are respectively counterclockwise. And turn clockwise.

  FIG. 3 shows the spillover state of the fault in the ring when the standby system is opened when the ADM of the present invention is used. Even if a failure occurs in the transmission line in the ring or another ADM 2, only one of the 0 system or the 1 system is affected. Here, the 1-system signal transmitted from the low-speed interface unit 13-1 of the ADM1 to the opposite device 23 of the ADM3 via the CCW and the low-speed interface unit 13-1 of the ADM3 to the opposite device 21 of the ADM1 via the CW. The 1-system signal to be transmitted is cut off.

  As a result, when two transmission path signals that are already redundant in the upper layer are accommodated by the ADM, even if a failure occurs in the ring, bidirectional transfer of only one of the 0 system and the 1 system becomes possible. Therefore, it is possible to realize a standby system release function capable of transferring without damaging the redundant configuration.

The figure which shows embodiment of ADM of this invention. The figure which shows the structural example of ADM at the time of backup system release. The figure which shows the spillover state of the failure in a ring at the time of a reserve system open | release at the time of using ADM of this invention. The figure which shows the general structure of ADM in normal UPSR. The figure which shows the spare system open | release structure at the time of using ADM in normal UPSR. The figure which shows the spillover state of the fault in a ring at the time of backup system opening | release at the time of using ADM in normal UPSR.

Explanation of symbols

11 High-speed interface unit (HSIF)
12 Branch Insertion Unit 13 Low Speed Interface Unit (LSIF)
15 Preliminary system opening control unit 21, 23 Opposing device

Claims (1)

Used for unidirectional path switching ring system (UPSR), which is a ring switching system,
A high-speed interface that switches between two types of clockwise and counterclockwise rings;
A low-speed interface unit having a 1 + 1 redundant configuration for performing redundant switching with a low-speed opposite device;
Branch insertion having a 1 + 1 redundancy configuration for switching redundancy when an equipment failure occurs, and a branch insertion unit for branching / inserting in units of transmission paths, located between the high speed interface unit and the low speed interface unit In type multiplexing terminal equipment,
The high-speed interface unit is a 0-system high-speed interface unit that transmits clockwise and receives counter-clockwise, and a 1-system high-speed interface unit that transmits counter-clockwise and receives clockwise.
Since the low-speed interface unit and the add / drop unit use one system as a redundant path , the low-speed interface unit and the branch / insertion unit correspond to the connection form of the 1 + 1 redundant configuration for performing the redundancy switching, and use both systems as active paths. The first active transmission path output from the low-speed interface unit of the system is connected to the 0-system branch insertion unit, and the second active transmission path output from the low-speed interface unit of the system 1 is connected to the branch-insertion unit of the system 1 Connect the first working transmission path that is connected and output from the 0-system branch insertion section to the 0-system low-speed interface section, and connect the second working transmission path that is output from the 1-system branch insertion section to the 1-system. Including a signal reception selector corresponding to the connection mode of the open standby system connected to the low-speed interface unit of
By operating the signal reception selector of the low-speed interface unit corresponding to an arbitrary transmission path and the signal reception selector of the add / drop unit, the redundant switching path or the first of the standby system is opened for the arbitrary transmission path. And an add / drop type multiplexing terminal station device comprising: a backup system release control unit that switches settings for setting the second two active transmission paths (backup system open paths).

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