JPH07264194A - Line associated operation device for atm exchange - Google Patents

Abstract

PURPOSE:To make the size of the line associated operation device small. CONSTITUTION:A line associated operation section 3 processes information from a subscriber terminal equipment 1 connecting to a subscriber terminal equipment 1 in th unit of cells. An SDH termination section 12 terminals a synchronization digital hierarchy multiplexing hierarchically the capacity of a transmission line through which an electric signal converted by a photoelectric conversion section 11 is sent. A cell synchronization section 13 detects a synchronizing signal of a cell by applying error control to the cell based on header error control information written in a cell header. A header conversion section 18 converts a virtual path identifier written in the cell header into a virtual path identifier being a destination by referencing a conversion table 180a storing the virtual path identifier written in the cell header and a destination virtual path identifier with cross reference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a subscriber switching device in a broadband ISDN, and in particular to an A provided in an ATM switching device.
The present invention relates to a line switching device of a TM exchange.

[0002]

Broadband ISDN is capable of providing a wide variety of multimedia such as voice, data, and video. Also, the ATM exchange transfers information in cell units in the asynchronous transfer mode, and can be applied to a wide range of communication from low speed to high speed. Therefore, in the broadband ISDN network, a line made of an optical fiber is connected to the ATM exchange.

In this wide-band ISDN, the bandwidth that subscribers should use is about several Mbps, and when there are few subscribers, the ATM switch, for example, has a 150 Mbps line with 50 to 1 Mbps.
It is enough to accommodate only 00 lines. When the number of subscribers is small, the line is effectively used by performing the multiplexing process in the transmission system 57 provided in front of the ATM switch 10 as shown in FIG.

Further, when the transmission system 57 multiplexes, the damage is great when a failure occurs in the wide band ISDN. Therefore, as shown in FIG. 22, the transmission system 57, the subscriber line corresponding unit 3, the switch 4, and the trunk line corresponding unit 30 have a dual configuration of the active system and the standby system, and when a failure occurs, the standby system is spared from the active system. I was switching to the system.

The subscriber line interface 3 is an interface for converting a signal sent from the subscriber terminal 1 by the synchronous digital hierarchy (SDH) into the ATM format and sending it to the switch 4. The switch 4 switches the internal signal path to send the cell to any trunk line.

In the subscriber line interface shown in FIG. 23, the optical / electrical converter 11 converts an optical signal from the subscriber line 53, which is an optical cable, into an electric signal, or vice versa. Convert the signal to an optical signal. The synchronous digital hierarchy (SDH) terminating unit 12 terminates the SDH format sent from the subscriber terminal 1 via the transmission system 57. The SDH format is such that, when multiplexing by the transmission system 57, the thickness of the transmission path (that is, channel capacity) is hierarchically (several stages) multiplexed so that signals can be efficiently and flexibly transmitted, and network synchronization is performed. Is intended. FIG. 24 shows the SDH format. The SDH frame has 9 columns in the vertical direction and 9 octets in the horizontal direction.
H) and a 261 octet virtual container (VC-4)
Composed of and. With this frame structure, the basic bit rate of SDH is unified to 155.52 Mbit / s.

FIG. 25 shows cell mapping to SDH frames. In the figure, the SDH frame has a path overhead (PO) as control information added to the virtual container.
H) is included. The SDH frame is mapped to an ATM cell composed of a header and user information.

The cell synchronization unit 13 performs cell error control based on header error control information written in the cell header in order to reduce cell loss due to a transmission line dot error resulting in an ATM cell header error. Perform sync detection.

Usage parameter control (UPC)
The unit 14 manages the bandwidth to be used by the user by monitoring the traffic volume. The charging unit 15 counts cells and notifies the processor of the information as charging information. Operation and Maintenance (OAM)
The section 16 manages an OAM cell (alarm cell). The monitoring cell (MC) unit 17 monitors the cell quality by measuring cell error characteristics, cell loss characteristics, cell delay characteristics, etc. using the MC cells.

The VPI / VCI conversion table 180 is input with a virtual channel identifier (VCI; Virtual Path).
Identifier) and virtual path identifier (VPI; Virtual C)
and a virtual channel identifier and a virtual path identifier of the output destination are stored in association with each other. The header conversion unit 18a reads the virtual channel identifier and the virtual path identifier written in the cell header to VPI / V.
By referring to the CI conversion table 180, the virtual path identifier is converted into the output destination virtual path identifier, and the virtual channel identifier is converted into the output destination virtual channel identifier.

The output destination path is determined for each cell by the output destination virtual channel identifier and the output destination virtual path identifier. In the microprocessor 19, the UPC unit 14,
The charging unit 15, the OAM unit 16, the MC unit 17, and the header conversion unit 18 are controlled.

[0012]

However, in order to realize the above-mentioned advanced functions, a lot of L lines are provided in the line interface.
SI was installed. Moreover, as the number of subscribers to the broadband ISDN increases, the number of line interface units also increases. As a result, the line interface becomes large. Further, in the case of being multiplexed and not being duplexed, when a failure occurs in a certain line interface, the line corresponding to the line interface is blocked. Therefore, there is also a problem that all the multiplexed subscribers cannot use the line.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a line interface device of an ATM switch which is intended to reduce the size of the line interface unit.

[0014]

The present invention has the following constitution in order to solve the above problems. FIG. 1 shows the principle of the present invention. The line corresponding device of the ATM exchange of the present invention is an AT
One subscriber terminal 1 through the subscriber line to the M switch 10
And a line interface 3 for processing the information from the subscriber terminal 1 in cell units.

The line interface 3 includes an opto-electric converter 11,
Synchronous digital hierarchy termination unit 12, cell synchronization unit 1
3, a conversion table 180a, and a header conversion unit 18. The photoelectric converter 11 converts an optical signal containing information from the subscriber terminal 1 into an electrical signal through the subscriber line.
The synchronous digital hierarchy termination unit 12 terminates the synchronous digital hierarchy for hierarchically multiplexing the capacity of the transmission path for transmitting the electric signal converted by the photoelectric conversion unit 11.

The cell synchronization section 13 is connected to the synchronous digital hierarchy termination section 12 and performs cell error control based on header error control information written in the cell header to detect cell synchronization. The conversion table 180a stores the virtual path identifier written in the cell header and the virtual path identifier of the output destination in association with each other for each cell synchronously detected by the cell synchronization unit 13.

The header conversion unit 18 uses the conversion table 18
By referring to 0a, the virtual path identifier written in the cell header is converted into an output destination virtual path identifier. Here, the subscriber line may be an optical cable using an optical fiber. The ATM switch may be applied to a broadband ISDN or a normal ISDN.

Further, the line interface 3 may use the entire band given to the subscriber line. In this case, since the conventional flow rate monitoring unit can be deleted by using the entire band, the configuration of the line corresponding unit can be simplified.

Further, a fixed charging unit 151 may be provided for notifying the exchange processor that it is a fixed charging subscriber without counting the number of cells. In this case, since it is not necessary to count the number of cells, the structure of the line interface can be simplified.

The line corresponding unit 3 is connected to one subscriber terminal 1 through the subscriber line, and is connected to another subscriber terminal 1 through the subscriber line corresponding unit 3-1 and the subscriber line and the PBX 2. The PBX line corresponding unit 3-2 to be connected is provided.

The subscriber line corresponding unit and the PBX line corresponding unit are an optical / electrical converting unit 11, a synchronous digital hierarchy termination unit 12, a cell synchronizing unit 13, a conversion table 180a,
The header conversion unit 18 is provided.

The opto-electric converter 11 converts an optical signal containing information from the subscriber terminal 1 into an electric signal through the subscriber line. The synchronous digital hierarchy termination unit 12 terminates the synchronous digital hierarchy for hierarchically multiplexing the capacity of the transmission path for transmitting the electric signal converted by the photoelectric conversion unit 11. The cell synchronization unit 13 is connected to the synchronous digital hierarchy termination unit 12 and performs cell error control based on header error control information written in the cell header to detect cell synchronization.

The conversion table 180a is the cell synchronization unit 1
The virtual path identifier written in the cell header and the virtual path identifier of the output destination are stored in correspondence with each other for each cell synchronously detected by 3. The header conversion unit 18 uses the conversion table 1
By referring to 80a, the virtual path identifier written in the cell header is converted into an output destination virtual path identifier.

The conversion table provided in the subscriber line corresponding unit 3-1 has a virtual path identifier smaller than the number of virtual path identifiers and virtual channel identifiers in the conversion table provided in the PBX line corresponding unit 3-2. Store the virtual channel identifier.

The number of virtual paths and virtual channels used by general subscribers is smaller than those of PBX subscribers. Therefore, the memory amount can be reduced by reducing the number of virtual path identifiers and virtual channel identifiers in the conversion table of general subscribers.

Further, the conversion table 180a has a first conversion table and a second conversion table. The first conversion table stores an internal identifier for limiting all virtual channel identifiers when a plurality of virtual paths are used simultaneously corresponding to the virtual path identifier and the virtual channel identifier written in the cell header for each cell.

The second conversion table stores virtual path identifiers and virtual channel identifiers of output destinations corresponding to the internal identifiers. The header conversion unit 18 converts the virtual path identifier and virtual channel identifier written in the cell header into an output destination virtual path identifier and virtual channel identifier by referring to the first and second conversion tables.

By using the internal identifiers in the first and second conversion tables, it is possible to limit all virtual channel identifiers when using a plurality of virtual paths at the same time. Also, by deleting the SDH termination part, full AT
It is possible to achieve M and simplify the configuration.

Further, the line interface unit 3 may include a plurality of working line interface units 31, one or more backup line interface units 34, and a switching unit. Each working line support unit 31
Is individually connected to each of the plurality of subscriber terminals 1 and generates a fault line identifier when a fault occurs.

The switching unit is connected to each working line corresponding unit 31 and protection line corresponding unit 34, and when a failure occurs in any one of the working line corresponding units 31, one of the protection line corresponding units 34 is based on the faulty line identifier. Switch to.

Here, the switching unit, for example, of an optical coupler for branching an optical signal from each subscriber line to a working line corresponding unit corresponding to the subscriber line and an optical signal input to the optical coupler. The optical switch may be configured to supply one optical signal to the protection line corresponding unit.

Further, in order to distinguish the upstream direction and the downstream direction of the optical signal between the subscriber terminal and the working line corresponding part, a plurality of optical signals having different wavelengths are used. Further, each subscriber terminal 1, each working line corresponding part 31 and protection line corresponding part 34 includes a wavelength demultiplexing / multiplexing part for demultiplexing and multiplexing a plurality of optical signals having different wavelengths.

By using this wavelength demultiplexing / multiplexing unit, bidirectional communication can be performed with one optical cable.

[0034]

According to the present invention, the line interface 3 is provided corresponding to one subscriber terminal 1, and information is input from the one subscriber terminal 1 to the line interface 3 through the subscriber line.

The optical signal containing the input information is converted into an electric signal by the photoelectric conversion unit 11. The synchronous digital hierarchy termination unit 12 terminates the synchronous digital hierarchy, and the cell synchronization unit 13 performs cell error control based on the header error control information written in the cell header, and the cell synchronization unit 13 performs cell synchronization detection.

Next, based on the cell header input to the header converter 18, the header converter 18 converts the conversion table 180.
The virtual path identifier of the output destination corresponding to the virtual path identifier written in the cell header in a is read and the virtual path identifier of the cell header is rewritten to the virtual path identifier of the output destination.

That is, since the line interface 3 is directly received by the subscriber terminal 1, even if a failure occurs in any of the subscriber lines, only that line is blocked. Moreover, since only the virtual path is provided as a service, it is not necessary to store the information of the virtual channel identifier in the conversion table. As a result, the amount of memory can be reduced by the information of the virtual channel identifier.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a line supporting device of an ATM exchange according to the present invention will be described below. <Example 1 of direct collection of subscribers> Fig. 2 shows example 1 of direct collection of subscriber lines
It is a configuration block diagram of. As shown in FIG. 2, the ATM switch 10-1 is provided with a subscriber line corresponding unit which constitutes a line corresponding device.
3 (3-1,3-2), switch for switching cells 4 (4a, 4
b), the relay line corresponding unit 30 (30a, 30b) is provided.

The subscriber line interface 3 is an interface for converting a signal sent from the subscriber terminal 1 by the synchronous digital hierarchy (SDH) into the ATM format and sending it to the switch 4. The switch 4 switches an internal signal path so as to send a cell according to the generated ATM format to any trunk line.

The subscriber terminal 1 is directly connected to the subscriber line interface 3-1 via a subscriber line 53 formed of an optical cable having an optical fiber. The subscriber terminal 1 is connected to the subscriber line interface 3-2 via a subscriber line 53 and a PBX (Private Branch Exchange) 2.

That is, one subscriber line interface 3
One subscriber terminal 1 is directly accommodated. Here, the optical fiber is characterized by including a core and a clad and having a small transmission loss.

In Example 1 shown in FIG. 2, since the conventional transmission system 55 shown in FIG. 21 is not used, the structure can be simplified. In addition, the line interface 3 corresponding to the subscriber line 53
Even if a certain line interface fails, only the line corresponding to that line is blocked. Therefore, there is an effect that the line can be used without affecting other subscribers. <Example 2 of direct collection of subscribers> Fig. 3 shows example 2 of direct collection of subscriber lines
It is a configuration block diagram of. In Example 2 shown in FIG. 3, ATM
It is characterized in that the subscriber line corresponding part in the exchange has a dual structure.

That is, the ATM switch 10-2 is provided with subscriber line corresponding units 3a-1 and 3a-2 as the 0 system (active system). Further, the ATM switch 10-2 is provided with subscriber line corresponding units 3b-1 and 3b-2 as one system (standby system).

Further, the ATM exchange 1-2 is equipped with a switch 40-1 for switching between the line corresponding part 3a-1 of the 0 system and the line corresponding part 3b-1 of the 1 system, and the line corresponding 3a- of the 0 system. A switching device 40-2 is provided for switching between the line 2 and the line corresponding part 3b-2 of the 0 system. The configurations of the switch 4 (4a, 4b) and the trunk line corresponding unit 30 (30a, 30b) are the same as those of the first example.

According to such a configuration, for example, when the 0-system line interface 3a-1 fails, the switch 40-1 allows the 0-system line interface 3a-1 to 1-line interface. Switch to section 3b-1. As a result, disconnection of the line can be prevented, so that the reliability of the device can be improved. <Example 3 of direct collection of subscribers> Fig. 4 shows example 3 of direct collection of subscriber lines
It is a configuration block diagram of. In the example 3 shown in FIG. 4, the N line-corresponding parts 3-1 to 3-N of 0 system are one line-corresponding part of 1 system.
It is characterized by sharing 3- (N + 1).

That is, the ATM switch 10-3 includes N line corresponding units 3-1 to 3-N of 0 system, N switchers 41-1 to 41-N and switcher 41-corresponding to these. 1-41-N and 1-system subscriber support section
The switch 42 is connected to 3- (N + 1). Also, A
The TM switch 10-3 includes a switch 43 connected to the line corresponding unit 3- (N + 1) of the 1-system and N line corresponding units 3-1 to 3-N of the 0-system.

The switches 41-1 to 41-N are provided corresponding to the N subscriber terminals 1-1 to 1-N. The other configurations are the same as the configurations of Example 1. According to such a configuration, when, for example, the line corresponding unit 3-1 among the N 0-type line corresponding units 3-1 to 3-N fails, the switching unit 41-1 is changed from the terminal a. It is switched to the terminal b. Then, it is connected to the line corresponding unit 3- (N + 1) of the 1-system via the switch 42 and the switch 43. Further, the failed line 0 corresponding to the line 3-1 is switched to the line corresponding to the line 1 3- (N + 1). As a result, disconnection of the line can be prevented, so that the reliability of the device is improved.

Further, a plurality of 1-system line-corresponding sections may be provided. In this case, if a failure occurs in the 0-system line interface, it may be switched to any one of the 1-system line interface units.

When all of the plurality of 1-system line corresponding parts are used, the 0-system cannot be switched to the 1-system, so that the line is blocked. <Example 1 of subscriber line interface> FIG. 5 is the same as FIG. 2 to FIG.
FIG. 3 is a configuration block diagram of Example 1 of a subscriber line interface shown in FIG. The subscriber line interface shown in FIG. 5 is made smaller than the conventional line interface.

In FIG. 5, the photoelectric conversion section (OE / EO) is shown.
The conversion unit 11 converts an optical signal from the subscriber line 53 composed of an optical cable into an electric signal, or vice versa. A cell synchronization unit 13 is connected to the photoelectric conversion unit 11.

The cell synchronization unit 13 performs cell error control based on the header error control information written in the cell header to detect cell synchronization. This cell is composed of a 5-byte header and a 48-byte information field.

FIG. 6 shows a cell format in ATM. The cell 200 shown in FIG. 6 includes a header 201 and an information field 202. The header 201 is 4-bit flow control information (GFC; Generic Flow Control).
l), 8-bit VPI, 12-bit VCI, 3-bit cell format information (PTI; Payload Type Identifie)
r), cell loss priority information (CLP; Cell Loss Priorit)
y), and control information (HE) of 8-bit header 201
C; Header Error Control).

In the ATM exchange, the routing, which is a call identification label, is assigned with information at the time of setting up a call and is released when the call is released. A unique value is assigned to the routing information for each link between the nodes, and it is necessary to convert the routing information every time the node passes through each node. For this purpose, a header conversion unit 18 described later is provided.

An OAM unit 16 is connected to the cell synchronization unit 13. The OAM unit 16 manages the alarm transfer cell. The MC unit 17 is connected to the OAM unit 16. MC part 1
Reference numeral 7 monitors the cell quality by measuring cell error characteristics, cell loss characteristics, cell delay characteristics, etc. using the management cell.

The header converter 18a receives the input V
PI / VCI is read and the header conversion table 180a is read.
VPI / VCI of the new output destination corresponding to this
Take out and rewrite the header.

The header conversion table 180a is composed of a memory accessible from the header conversion unit 18a and, as shown in FIG. 7, outputs tag information (TAG) and tag information (TAG) to an input VPI (user node interface; UNI). The above VPI (network node interface; NNI) is assigned. VPI of this output destination
Thus, the output destination path is determined for each cell.

The microprocessor 19 includes a charging unit 15,
It controls the OAM unit 16, the MC unit 17, and the header conversion unit 18a. (A) According to the line interface unit thus configured, first, the header conversion unit 18a converts only the VPI by referring to the header conversion table 180a shown in FIG.
Do not perform VCI conversion. Therefore, VC by VCI conversion
It is possible to reduce the memory amount of the conversion table by the number of I bits.

In this case, it is possible to realize a user virtual path (UVP) service in which the subscriber uses the virtual path (VP) like a dedicated line without performing VCI conversion. (B) Next, in the subscriber line interface 3 shown in FIG. 5, the UPC unit 14 is deleted from the conventional subscriber line interface. The UPC unit 14 manages the used bandwidth declared by the subscriber for the entire bandwidth (for example, 150 Mbps) given to the subscriber line.

In the present embodiment, by deleting the UPC unit 14, the line interface unit 3 uses the entire band given to the subscriber terminal 1. Therefore, it is possible to realize a service in which all the bands of a given line are used freely, and it is possible to downsize the line interface 3. (C) Further, in the line interface 3 shown in FIG. 5, the configuration of the charging unit 15 is simplified as compared with the conventional line interface.

The conventional charging unit 15 charges a fee according to the number of cells. The fixed charging unit 151 notifies the exchange processor that it is a fixed charging subscriber without counting the number of cells. That is, since the cells are not counted, the configuration can be simplified and a service with a fixed charge can be realized regardless of the line usage.

In this case, if a different line interface is provided for each service, the efficiency is poor. For example, a service that combines these, that is, you can freely use the bandwidth of the line,
The leased line service is one in which the charge is constant regardless of the amount used. If you use this leased line more often,
The amount of hardware can be reduced by preparing a line interface dedicated to services. (D) Furthermore, in the line interface shown in FIG. 5, the SDH terminal unit 12 is deleted from the conventional line interface.
Conventionally, the physical layer between the user's subscriber terminal 1 and the network is the SDH format, and the SDH terminating unit 12 terminates the SDH format as shown in FIG.

In the example shown in FIG. 5, full ATM conversion can be performed by deleting the SDH termination unit 12 from the subscriber line interface 3. As described above, by deleting a part of the subscriber line corresponding unit shown in FIG. 5 or simplifying the configuration, the subscriber line corresponding unit can be downsized. Note that any one of (a) to (d) or a combination of two or more may be performed. <Example 2 of Subscriber Line Corresponding Portion> FIG. 8 is a configuration diagram of a main part in Example 2 of the subscriber line corresponding portion. In FIG. 8, VPI /
VCI converter 18b, VPI accessible by this
/ VCI conversion tables 180 and 181 are shown. Other configurations are the same as those shown in FIG. In example 2,
VPI / VCI conversion table 18 for general subscribers
It is characterized in that the configuration of 1 is simplified.

In the example shown in FIGS. 2 to 5, the subscriber line 2 is directly accommodated in the subscriber line interface 3. Therefore, since the subscriber terminal 1 of a general subscriber or the private branch exchange (PBX) 2 is connected to the subscriber line 53, the subscriber terminal 1 and the PBX 2 of a general subscriber are separated for each subscriber line 53. To be done.

The VPI / VCI conversion table 180 is provided for a subscriber who uses PBX2, and the VP
The I / VCI conversion table 181 is provided for general subscribers.

Subscribers using PBX2 are likely to use many virtual paths (VP) and virtual channels (VC). Therefore, the VPI / VCI conversion table 180 shown in FIG. 8 stores VPI and VCI in UNI, and
In I, VPI and VCI are stored. In addition, TAG
The (tag) is used for in-device control (switch routing information). In UNI, VPI is 8 bits (256 lines) and VCI is 16 bits (65536).
Book). VPI and VC actually used
The number of I's is determined between the subscriber and the network.

On the other hand, the subscriber of the general subscriber terminal 1 rarely uses all the 8-bit VP and the 16-bit VC. Therefore, as shown in FIG.
The PI / VCI conversion table 181 stores 3 bits (8 lines) of VPI and 5 bits (32 lines) of VCI. In this case, 2 ^{8/2 24} memory capacity for the conversion table 180 required in the conversion table 181, i.e., can be reduced to 1/65536, the effect is large.

In this way, the general subscriber and the PBX subscriber are separated, and the number of VPI and VCI of the VPI / VCI conversion table 181 to be used for the general subscriber is limited. As a result, the amount of memory used can be reduced and the amount of hardware can be reduced. <Example 3 of subscriber line interface> Next, FIG. 9 is a block diagram of a main part of Example 3 of the subscriber line interface. In FIG. 9, V
PI / VCI conversion unit 18c, VPI / VCI conversion table 182 before reduction, first and second conversion tables 18
3, 184 and VP switch table 185 are shown. Other configurations are the same as those shown in FIG. Example 3
The feature is that the configuration of the VPI / VCI conversion table 182 is simplified. First, the VP is used to identify the type of service and the leased line to the ground, and to identify the carrier.
For example, VP is used for eight service types such as telephone, FAX, data communication, and leased line as shown in FIG. In addition, the number of VCs that have accessed each VP for Case 1 and Case 2 is shown.

As can be seen from case 1 in FIG. 10, since the number of people who can use each line is limited, many VCs must be used to identify each call when a plurality of accesses are made to one VP. Need. On the other hand,
As can be seen from Case 2 of 0, multiple services (V
When used over P), the number of VCs required per VP is small.

Therefore, the VPI / VCI of the VPI / VCI conversion table 182 is reduced by using the first and second conversion tables 183 and 184 shown in FIG. VPI / VC
The I conversion table 182 uses the UNI VPI of 3 bits, V
CI 5 bits, NNI TAG 12 bits, VPI
Is set to 12 bits and VCI is set to 16 bits.

The first conversion table 183 sets the usable VPI to 3 bits, the VCI to 5 bits, and the internal identifier indicating the number of all the VCIs that can be used simultaneously to 6 bits. In this case, the internal identifiers are provided by the number of all VCIs, and the usage state of the internal identifiers is managed so that the same internal identifier is not used in different VPI / VCIs.

The second header conversion table 184 has an internal identifier of 6 bits, an NNI VPI of 12 bits, and a VC of
I is set to 16 bits. Set TAG to 12 bits.

According to such conversion tables 183 and 184, the VPI / VCI conversion unit 18c temporarily converts the VPI / VCI of the sent cell into the internal identifier using the first conversion table 183. Further, the internal identifier converted using the second conversion table 184 is converted into a header for transmission.

For example, in the case of the conversion table 183,
Uses 8 VPIs (3 bits) and 32 VCIs (5
Bit) can be used. When using a plurality of VPs simultaneously, 64 combinations (6 bits) can be used.

In this case, V of the first conversion table 183
The reduction ratio for the PI / VCI conversion table 182 is about 1/7 of 2 ⁸ × 6 / (2 ⁸ × 40). Here, 40 represents the total number of used VCIs.

Further, the VPI of the third conversion table 184
The reduction ratio for the / VCI conversion table 182 is about 1/4 from 2 ⁶ × 40 / (2 ⁸ × 40).

As described above, by using the first and second conversion tables 183 and 184 to limit the number of all VCIs that simultaneously use a plurality of VPs with the internal identifier of 6 bits, the memory amount can be reduced. it can.

Further, the VP switch table 185 shown in FIG. 9 has a VPI of 3 bits and a UV without UV conversion.
1 bit of UVP that indicates whether to perform only P service,
The internal identifier at that time is stored as 6 bits. This V
When using the P switch table 185, the VCI
Since no conversion is performed, only one internal identifier needs to be used in one VP. In this case, the reduction ratio of the VP switch table 185 with respect to the VPI / VCI conversion table 182 is about 1/200 from 2 ³ × 7 / (2 ⁸ × 40), and the memory amount can be significantly reduced. <Example 4 of Subscriber Line Corresponding Section> FIG. 11 is a block diagram showing the configuration of Example 4 of the subscriber corresponding section. The subscriber corresponding unit shown in FIG. 11 is a plurality of individual units 31-1 to 31 provided for each subscriber terminal 1.
-N, a common unit 32 that is connected to each of the individual units 31-1 to 31-N and collectively processes them.

The individual parts 31-1 to 31-N are photoelectric conversion parts 11,
The SDH terminal unit 12, the cell synchronization unit 13, the UPC unit 14, the charging unit 15, and a common interface (INF) 38 connected to the common unit 32 are included.

The common section 32 includes a demultiplexing section 81 for multiplexing cells or demultiplexing cells, an OAM section 17, a VPI / V.
It is composed of the CI conversion unit 18. The same parts as those shown in FIG. 5 are designated by the same reference numerals, and their details are omitted. When performing the multiplexing, the demultiplexing unit 81 transfers each cell data from a plurality of lines as serial data.

According to this structure, the demultiplexing unit 81, the OAM unit 17, the VPI / VC provided in the common unit 32 are provided.
Since the I conversion unit 18 is made common to each individual unit, the configuration of the line corresponding unit 3 can be simplified. <Example 1 of Switching System of Individual Unit> FIG. 12 is a configuration diagram showing Example 1 of the system switching system when the individual unit fails. The system switching system shown in FIG. 12 is a more specific version of the configuration shown in FIG. 4 and the configuration shown in FIG. The line-corresponding part has N active systems, that is, 0-system individual parts 31-1 to 31.
-N and one spare system, that is, an individual unit 34 of one system and a common unit 32a of 0 system and a common unit 32b of 1 system corresponding thereto. The 0-system switch 4a and the 1-system switch 4b are connected to the common parts 32a and 32b.

The N individual units 3-1 to 3-N of the 0 system output the faulty line identifier 36 to the common unit 32 and the optical selector 60 described later when the self unit fails. The optical selector 60 connects the N lines on the input side to the N individual units 3-1 to 3-N of the 0 system, receives the faulty line identifier 36 from the faulty individual unit, and sets the faulty individual unit to 1 Switch to the individual unit 34 of the system. The input side of the optical decoder 70 is connected to N lines, and the output side is connected to N 0 individual units 3-1 to 3-N and 1 individual unit 34.

According to such a configuration, first, when a certain 0-system individual unit, for example, the individual unit 3-1 fails, a fault line identifier (also referred to as a fault flag) 36 from the individual unit 3-1. stand. Then, the failed line identifier 36 is sent to the common unit 32 and the optical selector 60. Optical selector 60
Uses the failed line identifier 32 as an optical selector switching signal,
The failed individual unit 3-1 is switched to the individual unit 34.

On the other hand, the faulty line identifier 36 sent to the common unit 32 becomes a select signal for selecting N units from the N + 1 individual units of the demultiplexing unit 81 of the common unit 32. The demultiplexing unit 81 removes the failed 0-system individual unit 3-1 from N lines, selects the 1-system individual unit 34, and performs N: 1 multiplexing.

The above is the upstream side (from the subscriber to the switch)
Is the explanation. When there is a person who wants to send information to the person who has failed, the optical decoder 70 is a downstream side (switch to subscriber), that is, an individual unit of the 1-system so that the person who wants to send information sends information to the person who has failed 34 is switched.

Although only one 1-system individual unit 34 is provided in the above configuration, a plurality of 1-system individual units 34 may be provided, for example. FIG. 13 is a detailed configuration diagram of the optical selector shown in FIG. 12 for performing system switching. In FIG.
The optical selector 60 includes optical couplers 61-1 to 61-N provided corresponding to N subscriber lines 53, and optical switches 62 connected to the optical couplers 61-1 to 61-N. Each optical coupler 61-1 ~
61-N is a corresponding 0-system individual unit 3-through the optical fiber 53
Connected to 1-3-N. The optical switch 62 is an individual unit of the 0 system.
In response to the faulty line identifier 36 from 3-1 to 3-N, the optical coupler corresponding to the failed 0-system individual unit and the 1-system in order to switch the failed 0-system individual unit to the 1-system individual unit 34. And the individual unit 34 of.

According to such a configuration, first, the optical signal from the optical fiber 53 which is the subscriber line is input to the optical selector 60 mounted in the line interface. The optical signal is sent by the optical couplers 61-1 to 61-N in the optical selector 60 to the individual unit 0-system 3-
Sent to 1-3-N. Here, when an abnormality occurs in any of the individual units of the 0 system, the fault line identifier 36 sent from the faulty individual unit is used as a switching signal for the optical switch 62 and a fault is stored in the optical switch 62. The subscriber is connected to the individual unit 34 of the 1-system. The multiplexing unit 81a multiplexes N cells of the 1-system individual unit 34 and the 0-system individual unit.

That is, the optical switch 62 can be switched by the failed line identifier 36 from the individual unit of the 0-system, which has also failed on the upstream side from the subscriber to the switch 4, and the recovery can be promptly restored. Further, since the optical couplers 61-1 to 61-N are housed in the optical selector 60, the optical switch 62 is not affected even when the failed individual unit is inserted or removed. Figure 1
4 is a detailed configuration diagram of the optical decoder for switching the system shown in FIG. In FIG. 14, an optical decoder 70 is an optical coupler 61-1 to 61 provided corresponding to N subscriber lines 53.
-N and an optical switch 62 connected to the optical couplers 61-1 to 61-N. Each of the optical couplers 61-1 to 61-N is connected to the corresponding individual unit via the optical fiber 53. The optical switch 62 receives the failed line identifier 36 from the individual unit and switches the failed individual unit of the 0-system to the individual unit 34 of the 1-system, and the optical coupler corresponding to the failed individual unit and the individual unit 34 of the 1-system. And connect.

According to such a configuration, when an abnormality occurs in any of the individual units of the 0 system, the faulty line identifier 36 sent from the faulty individual unit is used as an optical switch 62 switching signal. The failed subscriber accommodated in the switch 62 is connected to the individual unit of the 1-system.

That is, the down side from the switch 4 to the subscriber can also switch the optical switch 62 by the faulty line identifier 36 to recover immediately. <Example 2 of Switching System of Individual Unit> FIG. 15 is a configuration diagram showing Example 2 of the switching system of the individual unit. In the switching system shown in FIG. 15, the upstream optical selector and the downstream optical decoder shown in FIG. 12 are integrated.

The subscriber terminals (TE) 1-11 to 1-1N are E / O
Sections 11a-1 to 11a-N, O / E sections 11b-1 to 11b-N, and a wavelength division multiplexing (WDM) unit 26-1 connected to them and performing demultiplexing or multiplexing of different wavelengths. ~ 26
-With N. The WDMs 26-1 to 26-N input two wavelengths λ ₁ and λ ₂ and distribute the information on the upstream side and the downstream side.

The optical selector 60a includes N optical couplers 61-1 to 61-N, which are common to the upstream side and the downstream side, and one optical switch 62. The optical fiber 53 is connected to each of the optical couplers 61-1 to 61-N.
The WDMs 26-1 to 26-N are connected via the.

The individual units 3-11 to 3-1N of each 0 system are WDM2
6-1 to 26-N, E / O section 11a-1 to 11a-N, O / E section 11b-1 to 11
with bN. Individual system 34A of 1 system is WDM26A, E / O
A section 11A and an O / E section 11B are provided.

The common unit 32 includes a multiplexing unit 8a and a demultiplexing unit 8b. The outputs of the E / O units 11a-1 to 11a-N are connected to the separating unit 8b. The outputs of the O / E units 11b-1 to 11b-N are connected to the multiplexing unit 8a. Although not shown, the O / E unit 11b-
An SDH terminating unit, a cell synchronizing unit, a common unit interface, etc. are provided between 1 to 11b-N and the multiplexing unit 8a.

According to the optical selector and the peripheral circuit configured as above, the subscriber terminals (TE) 1-11 to
The optical signal having the wavelength λ ₁ converted from the electric signal by the E / O units 11a-1 to 11a-N in 1-1N is transmitted through the optical fiber 53 through the WDMs 26-1 to 26-N, and the optical coupler 61 is used. -1 to 61-N. Then, the optical signal passes through the WDMs 26-1 to 26-N in the individual units via the optical fiber 53, and the O / E units 11b-1 to 1 to 1
Converted to electrical signals by 1b-N, SDH processing and ATM
After the processing, it is taken into the multiplexing unit 81a. Further, the multiplexing unit 81a multiplexes the electric signals from the individual units.

On the downstream side, on the other hand, each electric signal corresponding to the wavelength λ ₂ separated by the separating unit 8b is converted into an optical signal of the wavelength λ ₂ by each E / O 11a-1 to 11a-N in each individual unit. , WDM 26-1 to 26-N, and the optical fiber 53 to take in the optical couplers 61-1 to 61-N. After that, the optical signal of wavelength λ ₂ passes through WDM in TE through the optical fiber 53,
It is converted into an electric signal by O / E.

When a failure occurs in any one of the N individual units of the 0 system, the individual unit 34 of the 1 system is used.
Switch to A. That is, bidirectional communication is possible with one optical fiber 53 by communicating using different wavelengths on the upstream side and the downstream side. Also, the optical selector 6
The size of 0a can be formed on one surface without changing the size, and the number of optical fibers 53 extending between the devices can be reduced to half compared with the case shown in FIG. <Example 3 of Switching System of Individual Unit> FIG. 16 is a configuration diagram showing Example 3 of the switching system of the individual unit. In the switching system shown in FIG. 16, TE 1-21 to 1-2N and individual units 3-21 to 3-2N
2 × 2 couplers 27-1 to 27-N and optical isolators 28-1 to 28
-N and is provided. The optical isolators 28-1 to 28-N transmit signals only in one direction. 2 for optical isolators 28-1 to 28-N
× 2 couplers 27-1 to 27-N are connected. This 2x2 coupler
27-1 to 27-N have two input terminals and two output terminals,
Transmit signals in both directions.

Instead of providing the 2 × 2 couplers 27-1 to 27-N and the optical isolators 28-1 to 28-N, the W shown in FIG. 15 is used.
DM26-1 to 26-N were deleted. The other configurations are the same as the configurations shown in FIG. 15, and thus details thereof will be omitted.

According to such a configuration, on the upstream side, the optical signal of the wavelength λ ₁ is transmitted by the optical isolators 28-1 to 28-N and 2 × 2.
The optical fiber 53 is transmitted through the couplers 27-1 to 27-N and taken in by the optical couplers 61-1 to 61-N. The optical signal is converted into an electric signal by the O / E unit via the 2 × 2 couplers 27-1 to 27-N in each individual unit via the optical fiber.

On the other hand, on the downstream side, each electric signal is converted into an optical signal of wavelength λ ₂ by each E / O unit in each individual unit, and the optical isolators 28-1 to 28-N and the 2 × 2 coupler 27-1 are used. ~ 27-N and taken into the optical couplers 61-1 to 61-N. The optical signal of wavelength λ ₂ is transmitted through the optical fiber 53 to the 2 × 2 coupler in TE.
It passes through 27-1 to 27-N and is converted into an electric signal by the O / E section.

Even if such optical isolators 28-1 to 28-N and 2 × 2 couplers 27-1 to 27-N are used, the same effect as that of the optical selector as shown in FIG. 15 can be obtained. Also,
In this case, since the optical isolator is used, the influence on the signal coming from the opposite direction is particularly small. <Example 4 of Switching System of Individual Unit> FIGS. 17 and 18 show Example 4 of the switching system of the individual unit. FIG. 17 is a configuration diagram on the upstream side of the switching system of the individual units. FIG. 18 is a configuration diagram on the down side of the switching system of the individual units.

The optical selector 60b shown in FIG.
Parts 11b-1 to 11b-N, electric switches 63 connected to them
It is configured with. Optical decoder 70b shown in FIG.
Also includes O / E units 11b-1 to 11b-N and electric switches 63 connected to them. Also, the O / E section 11b-1
11b-N are individual units 3-1 to 3- of the 0 system via the electric signal line 55.
Connected to N. The electric switch 63 has an individual unit 3 of one system
4B is connected.

In such a configuration, TE1-21 to 1-2N
The optical signal coming from the O / E unit 11b-1 to 11b-N is converted into an electric signal, and the electric signal is transmitted from the O / E unit 11b-1 to 11b-N to each individual unit through the electric signal line 55. To do so. With this configuration, it is not necessary to provide the O / E unit and the E / O unit in each of the individual units 31-1 to 31-N, and the physical size can be reduced.

FIG. 19 is a structural diagram of the package shelf of the individual part and the common part. A package shelf 300 shown in FIG. 19 has a plurality of individual units 31 and a common unit 32 in the line interface 3 mounted on a board.

On the outer surface of a back wiring board (hereinafter referred to as BWB) 301 which is a substrate, O / E and E / O for the O / E and E / O parts connected to the TE1 are provided.
A module 311, a common module 314 for the common 32, O / E and E connected to the switch 4.
An O / E and E / O module 316 for the / O section is mounted.

The common portion 3 is provided on the inner surface of the BWB 301.
2 is mounted on the package substrate 315, and the individual unit 3
Each component No. 1 is mounted on the package substrate 313. Here, nine package substrates 313 are provided corresponding to nine subscriber terminals 1.

On the inner surface of the BWB 301, a plurality of optical couplers 61 and optical switches 62 are mounted on a package board 312, and a connector 320 provided on this package board 312.
And the corresponding connector 321 to connect to the subscriber terminal 1
The incoming optical fiber 52 is housed in the optical coupler 61 from the side of the shelf.

Then, these package substrates 312,
313 and 315 are provided orthogonally to the BWB 301. That is, the common unit 32 is different from the BWB 301 in the individual unit 31.
Along with the bookshelf type.

As described above, the line corresponding part is divided into the individual part and the common part, and the O / E and E / O are arranged in the BWB for each individual part, whereby the device can be downsized. Figure 20
Is a rack mounting configuration diagram. The rack 250 shown in FIG. 20 has a rectangular shape and has a door 340 on the front surface. Rack 25
A plurality of package shelves 300 as shown in FIG. Each package shelf 3
00 is removable from the rack 250.

Further, the package shelf 300 accommodates a package board 313 for a plurality of individual parts and a package board 315 for a common part, and these package boards 313, 315 are mounted on the package shelf 300 by the package connector 330. It is supposed to be fixed.

With such a configuration, a plurality of miniaturized line corresponding parts can be accommodated in one rack 250, and each package shelf 300 can be easily replaced.

[0111]

According to the present invention, in the line interface of the ATM switch, the line interface can be miniaturized by deleting a part of each part of the line interface. This largely contributes to the realization of a large-capacity switching device for wideband ISDN.

[Brief description of drawings]

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

FIG. 2 is a configuration block diagram of a first example of direct receipt of a subscriber line.

FIG. 3 is a configuration block diagram of a second example of direct receipt of a subscriber line.

FIG. 4 is a configuration block diagram of a third example of direct receipt of a subscriber line.

5 is a configuration block diagram of Example 1 of the subscriber line corresponding unit shown in FIGS. 2 to 4; FIG.

FIG. 6 shows a cell format in ATM.

FIG. 7 is a diagram showing a conversion table.

FIG. 8 is a configuration diagram of a main part of an example 2 of a subscriber line corresponding part.

FIG. 9 is a configuration diagram of a main part of an example 3 of a subscriber line corresponding part.

FIG. 10 is a diagram showing an example of use of VPI / VCI.

FIG. 11 is a configuration block diagram of a fourth example of a subscriber corresponding unit.

FIG. 12 is a configuration diagram showing an example 1 of a switching system of an individual unit.

13 is a detailed configuration diagram of an optical selector that performs system switching shown in FIG.

FIG. 14 is a detailed configuration diagram of an optical decoder which performs system switching shown in FIG.

FIG. 15 is a configuration diagram showing an example 2 of a switching system of an individual unit.

FIG. 16 is a configuration diagram showing an example 3 of a switching system of an individual unit.

FIG. 17 is a configuration diagram on the upstream side of the switching system of the individual unit.

FIG. 18 is a configuration diagram on the down side of the switching system of the individual unit.

FIG. 19 is a configuration diagram of a package shelf.

FIG. 20 is a configuration diagram of rack mounting.

FIG. 21 is a diagram showing a configuration example of a conventional wideband ISDN.

FIG. 22 is a diagram showing an example of a conventional duplex configuration.

FIG. 23 is a block diagram of a conventional subscriber line interface.

FIG. 24 is a diagram showing an SDH format.

FIG. 25 is a diagram showing cell mapping to an SDH frame.

[Explanation of symbols]

 1. Subscriber terminal 2. Private branch exchange 3. Subscriber line interface 4. Switch 10 ATM switch 11. Photoelectric conversion unit 12. SDH termination unit 13. Cell synchronization unit 14. UPC Part 15 Billing unit 16 OAM unit 17 MC unit 18 VPI / VCI converter 18a VPI converter 19 Microprocessor 26 WDM 27 2x2 coupler 28 Optical Isolator 30..Relay line corresponding part 31..0 system individual part 32..common part 34..1 system individual part 40..switch 53..subscriber line 55..electrical signal line 57..transmission System 60 ... Optical selector 61 ... Optical coupler 62 ... Optical switch 70 ... Optical decoder 81 ... Demultiplexing unit 82 ... OAM unit 110 ... ATM format unit 150 ... Cell counting unit 180 ... PI / VCI conversion table 180a ·· VPI conversion table

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location 9466-5K H04L 11/20 D (72) Inventor Satoshi Kuroyanagi 1015 Kamitadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Within Fujitsu Limited (72) Yutaka Ezaki Yutaka Ezaki 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited (72) Inventor Akira Hakuda, 1015 Kamedanaka, Nakahara-ku, Kawasaki, Kanagawa Prefecture Within Fujitsu Limited (72) Inventor Tsuguo Kato 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Tetsuya Nishi, 1015, Kamikodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Hidenao Nakajima, Kawasaki, Kanagawa Prefecture 1015 Kamiodanaka, Nakahara-ku, Yokohama Within Fujitsu Limited (72) Inventor Shuhei Fujita 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Earth Fujitsu within Co., Ltd. (72) inventor Watanabe Yoshionore Kanagawa Prefecture, Nakahara-ku, Kawasaki, Kamikodanaka 1015 address Fujitsu within Co., Ltd.

Claims (7)

[Claims] 1. A line interface connected to an ATM exchange (10) through a subscriber line to one subscriber terminal (1) and processing information from the subscriber terminal (1) in cell units having a cell header. (3), the line corresponding unit (3), an optical-electrical conversion unit (11) for converting an optical signal containing information from the subscriber terminal (1) into an electric signal through the subscriber line, A synchronous digital hierarchy termination unit (12) for terminating a synchronous digital hierarchy for hierarchically multiplexing the capacity of a transmission line for transmitting the electric signal converted by the electric conversion unit (11), and the synchronous digital hierarchy termination unit (12). A cell synchronization unit (13) connected to the cell header and performing cell error control based on header error control information written in the cell header to detect cell synchronization; (13) by a conversion table of the virtual path identifier written to the cell header for each sync detected cell output destination virtual path identifier stored in correspondence (18
0a) and a header conversion unit (18) for converting the virtual path identifier written in the cell header into an output destination virtual path identifier by referring to the conversion table (180a). Switch line support device. 2. The fixed line charging unit (151) according to claim 1, wherein the line interface (3) notifies the exchange processor of a fixed charging subscriber without counting the number of cells. A line-corresponding device for an ATM exchange, characterized by being provided. 3. A line interface device for an ATM switch according to claim 1, wherein the line interface (3) uses the entire band given to the subscriber line. 4. The subscriber line corresponding unit (3-1) according to claim 1, wherein the line corresponding unit (3) is connected to one subscriber terminal (1) through a subscriber line. And a PBX line corresponding unit (3-2) connected to another subscriber terminal (1) through the PBX (2), the subscriber line corresponding unit and the PBX line corresponding unit being the subscriber line. A photoelectric conversion unit (11) for converting an optical signal containing information from the subscriber terminal (1) into an electric signal through the transmission line, and a capacity of a transmission line for transmitting the electric signal converted by the photoelectric conversion unit (11). Based on header error control information written in the cell header, which is connected to the synchronous digital hierarchy termination unit (12) and terminates the synchronous digital hierarchy termination for hierarchical multiplexing of A cell synchronization unit (13) that performs cell error control by performing cell error control, and a virtual path identifier and an output destination virtual path written in a cell header for each cell whose synchronization is detected by the cell synchronization unit (13). A conversion table (18
0a) and a header conversion unit (18) for converting the virtual path identifier written in the cell header into an output destination virtual path identifier by referring to the conversion table (180a), the subscriber line interface unit The conversion table provided in (3-1) stores virtual path identifiers and virtual channel identifiers that are less than the number of virtual path identifiers and virtual channel identifiers in the conversion table provided in the PBX line corresponding unit (3-2). A line support device for an ATM exchange, characterized by: 5. The conversion table (180a) according to claim 1, wherein all virtual channels when a plurality of virtual paths are used simultaneously corresponding to a virtual path identifier and a virtual channel identifier written in a cell header for each cell. The header conversion includes a first conversion table storing an internal identifier for limiting an identifier, and a second conversion table storing an output destination virtual path identifier and a virtual channel identifier corresponding to the internal identifier. The unit (18) converts the virtual path identifier and the virtual channel identifier written in the cell header into an output destination virtual path identifier and a virtual channel identifier by referring to the first and second conversion tables. A line compatible device for an ATM exchange. 6. The working line according to claim 1, wherein the line interface (3) is individually connected to each of a plurality of subscriber terminals (1) and generates a faulty line identifier when a fault occurs. Corresponding part (31), one or more protection line corresponding parts (34), each working line corresponding part (31) and protection line corresponding part (34)
An ATM switch which is connected to any one of the above-mentioned working line corresponding parts (31) and is switched to any one of the protection line corresponding parts (34) based on the failed line identifier. Line compatible device. 7. The optical signal according to claim 6, wherein a plurality of optical signals having different wavelengths are used to distinguish the upstream direction and the downstream direction of the optical signal between the subscriber terminal and the working line corresponding unit. Each of the subscriber terminals (1) and each of the working line corresponding unit (31) and the protection line corresponding unit (34) includes a wavelength demultiplexing / multiplexing unit that demultiplexes and multiplexes the plurality of optical signals having different wavelengths. A line compatible device for an ATM exchange.