JPH10145374A - Packet connection system switching method and asynchronous transfer mode communication device - Google Patents

Abstract

(57) [Summary] To easily and quickly switch a redundant configuration in an ATM area. A working VC10-0 and a protection VC10-1 are provided in turns of ATM communication devices 1-1 and 1-2, and a transmission-side ATM communication device 1-1 has a working VC10-0.
A user cell is transmitted only to C. ATM on the receiving side
In the communication device 1-2, a connection is set so that both the cells of the working VC and the cells of the protection VC can be transmitted downstream. When a failure occurs, only the transmitting-side ATM communication device can complete the switching by changing the cell transmission destination to the working or protection VC.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet communication apparatus, and more particularly to an asynchronous transfer mode (ATM) for handling fixed-length packets (hereinafter, referred to as cells).
er Mode).

[0002]

2. Description of the Related Art A public communication network, a bank communication network, and the like are required to have high reliability so that communication is not interrupted even during maintenance work or a failure. As means for realizing such high reliability, a spare communication path is prepared for a certain communication path as shown in FIG. 2, and communication is performed using the spare communication path at the time of maintenance work or failure. Therefore, a method (protection) of avoiding interruption of communication is known. In FIG. 2, communication is performed between the two terminals 20, and the communication device 1-1 and the communication device 1
A working connection (a connection used for communication in a normal state) and a protection connection (a connection used because the working connection cannot be used) are set between -2. Each of the working connection and the protection connection connects the communication devices via different networks 21. In this case, even when a failure occurs in the network A21 and communication becomes impossible, communication can be performed via the protection connection 10-2.
Communication between zeros is not interrupted.

[0003] The terms working, protection, working and spare used in the present invention are defined here. Working refers to what is considered to be normally used at the start of communication, and protection refers to something that is not normally used at the start of communication but is used only when working is switched due to a failure or the like. In addition, the term “active” refers to a device that is being used for communication at a certain point in time, and the “reserve” refers to a device that is not used for communication at a certain point in time and is on standby.

FIG. 3 shows an ITU-T (International Telecom)
munication union), SDH
1 shows a functional configuration of an apparatus that realizes protection in (Synchronous Digital Hierarchy). This figure is ITU
-T Recommendation G. Extracted from 783. Working Channel 1
(25-1), 2 (25-2) are the signals to be communicated, usually Wor
It is communicated using king Section 1 (26-1) and 2 (26-2). Working Section 26, Protection Secti
on28 is prepared. In the Protection Section, signals of Extra Traffic Channel 27 are normally transmitted.
Communication is continued using. Specifically, Working
The transmission side bridge 23-2 of Channel 1 (25-1) and 2 (25-2) is released, and the reception side selector 24-2 is Workin.
g Section is selected. If there is no need to communicate Extra Traffic, Protection Channel 28
Since the Null signal is flowing, the selector 24-4 is released,
Bridge 23-4 is also open. SDH protection includes 1 + 1, 1: 1, 1: n, m: n, and the like, but FIG. 1 shows the case of 1: n (including the case of n = 1).

[0005] The signal of Working Channel 25 is actually transmitted to Worki.
When changing from ng Section 26 to Protection Section 28, bridge 23 on the transmitting side and selector 2 on the receiving side
4 must be switched. For example, Working Chan
When switching the nel (25-1) to the protection section, first connect the bridge 23-2 of the working channel 1 of the transmitting bridge, and then the working channel of the opposing communication device.
The selector 24-2 on the receiving side of nel1 is switched to the protection side. This is done in both directions.

[0006] The communication path can be switched even in the ATM layer. FIG. 4 shows an example of the device configuration of the ATM switch.
Shown in A plurality of line cards 3 each accommodating an interface circuit (input side RV: 5, output side TR: 6) accommodating transmission lines 7 (7-1 to 7-n) each comprising a pair of input lines and output lines. (3-1 to 3-n) and an ATM switch (ATMSW) 2 for distributing an input cell passing through each interface circuit to one of the interface circuits according to routing information included in the cell header.
And a control unit 4 connected to the interface circuit 3 and the ATM switch 2 via a control system transfer path 8.

Each interface circuit performs a transmission line operation such as an optical / electrical conversion operation for converting an optical signal into an electric signal for an input signal from an input line and an electric / optical conversion operation for an output signal to an output line. And a physical layer processing function for performing signal processing in the physical layer for signals transmitted to and received from the H.7, for example, header information (VPI / VCI) of an input cell by referring to a header conversion table, and header information for an output cell. Header conversion and OAM
It has an ATM layer processing function for performing signal processing in the ATM layer for input / output cells, such as an (Operation And Maintenance) function.

The connection switching method of the ATM layer is described in Japanese Patent Application Laid-Open No. 7-74747.
According to the invention, the connection switching of the ATM layer is performed by the input side line card 3 to the ATM communication apparatus 1 by the AT.
This is performed by replacing the M cell header. FIG. 5 shows a configuration example of the line card 3. The line card 3 receives a signal from the ATM SW 2 and transmits the signal to the transmission line 7 (TR, 6).
A receiving circuit (RV, 5) for transferring a signal to the M SW2,
An MPU 97 for controlling the line card 3, an external RAM (96) thereof, and a control unit communication processing unit 98 for communicating with the control unit 4 of the communication device. Receiver circuit 5
Then, the signal is received from the transmission path 7, the receiving side physical layer processing section 95-i performs the physical layer termination processing, and the receiving side A
The TM layer processing unit 94-i performs header conversion, performance information acquisition, and the like of the ATM cell, and transfers the signal to the ATM SW2 via the I / O processing unit 90-o. In the transmission side circuit 6,
A signal is received from the ATM SW2 (I / O processing unit 90-
i), the output-side performance information acquisition and the like are performed by the transmission-side ATM layer processing unit 94-o, and the transmission-side physical layer processing unit 95-o performs framing and the like on the physical layer, and transmits a signal to the transmission path 7.

The detailed configuration of the receiving-side ATM layer processing unit 94-i and the transmitting-side ATM layer processing unit 94-o and the operation of header conversion will be described with reference to FIGS.

In the receiving side ATM layer processing section 94-i,
The ATM cell is received from the receiving side physical layer processing unit 95-i. First, the header of the ATM cell is received by the header analysis unit 1 on the receiving side.
It is cut out at 35. The transmission header is obtained from the cut-out header by searching the reception side CAM 139 and the reception side RAM 141, the header conversion unit 137 changes the cell header, and transfers the cell to the ATM SW2.

FIG. 7 shows an example of a header conversion method. The receiving side CAM (Content Addressable Memory) 139 can extract the connection number 151 from the input side VCI (Virtual Connection Identifier) 150. The connection number 151 has a one-to-one correspondence with the address of the reception-side RAM 141, and the output route 152, the output VCI
153 including the information of the desired connection.
Can be extracted from M141. Receiving CAM14
0, the contents of the receiving RAM 141 are set by the MPU 97 when the connection is set.

Regarding the protection of the ATM layer, according to Japanese Patent Laid-Open Publication No. 7-74747, the output side header of both the working and the protection connection is stored in the reception side RAM 141 in the reception side RAM, and which of the active side is used. Is displayed, the active system display 156 is stored. When the cell arrives, the receiving side CAM 139 extracts the connection number, converts the cell header to the output route and output VCI on the side where the active system is displayed, and sends the cell. As a result, a cell is transmitted to a desired connection in the switch unit.

FIG. 8 shows a flowchart of the cell header conversion in the receiving side ATM layer processing section. When a cell arrives (41), a cell header is first cut out (43), a connection number is searched from the receiving CAM 139, information about the cell header is read from the receiving RAM 141, and the working system is working (45). Attaches a header of the working connection (46), and in the case of protection (45), attaches a header of the protection connection (49) and sends the cell (47).

[0014]

One connection has one working connection and one protection connection, and the resources (bandwidth and route) of the protection connection are secured. Consider a 1: 1 protection configuration in which is not flowing.

In the SDH protection, as shown in FIG. 3, when switching is performed, it is necessary to switch both the bridge 23 on the transmitting side and the selector 24 on the receiving side. Further, this requires a procedure, and therefore, for example, even when a one-way connection is switched from working to protection, it is necessary to perform communication for switching between the transmitting side and the receiving side. In the SDH, the number of paths multiplexed on one transmission line is small, but in the ATM layer, the number of connections multiplexed on one transmission line is, for example, 4096 connections, which is very large. Therefore, there is a problem that the switching time is required.

Further, when performing protection, it is necessary to check whether or not the connection at the switching destination is conductive. Therefore, even when the working system is, for example, a working system, it is necessary to flow cells to the protection side. In the conventional method, it is difficult to send a specific cell to a backup connection by replacing a header on the input side of the ATM communication device 1.

A first object of the present invention is to provide a packet connection system switching method and an asynchronous transfer mode communication device capable of realizing connection switching by switching only the transmitting side of the connection to be switched.

A second object of the present invention is to provide a packet connection system switching method and an asynchronous transfer mode communication device capable of transferring cells even to a redundant system of a redundant connection.

A third object of the present invention is to provide a method for switching a packet connection system for identifying cells of the same VCI coming from a working system and a protection system, and an asynchronous transfer mode communication device.

[0020]

In order to solve the first object, in a receiving-side ATM device having a 1: 1 redundant configuration, the same RTG and VCI are connected to the input line card of a working connection and a protection connection by a cell. Is performed so that cells coming from the working connection and the protection connection are mixed in the output side line card.

To solve the second object, the receiving side AT
The header conversion unit of the M layer processing unit is provided with a function of selectively adding a cell header on the standby side according to the cell.

In order to solve the third object, a number uniquely assigned to each interface is provided, and the number of the receiving-side ATM layer processing unit is converted into an internal cell header by a header conversion unit of the receiving-side ATM layer processing unit. Area or H
The number is assigned to the EC area, and the transmitting side ATM layer processing unit identifies whether the cell has arrived from the working connection or the protection connection based on the number.

[0023]

FIG. 1 shows an embodiment according to the present invention for the first object, which realizes 1: 1 protection by switching only on the transmission side.

The ATM communication device 1 comprises a line card 3 for accommodating a transmission line, an ATM SW 2 for exchanging ATM cells, and a control unit 4 for controlling these. A
The TM communication device 1 (1-1) and the ATM communication device 2 (1-
2) is connected via a transmission line 7. An ATM connection is set up over the section between the ATM communication device 1 (1-1) and the ATM communication device 2 (1-2), and the connection has a 1: 1 redundant configuration between the two ATM communication devices. . Working connection 10-0 is A
Line card 2 (3-2) of TM communication device 1 (1-1)
And the line card 2 (3-) of the ATM communication device 2 (1-2)
The protection connection 10-1 is set via the line card 3 (3-3) of the ATM communication device 1 (1-1) and the line card 3 (3-3) of the ATM communication device 2 (1-2). -3). Normally, communication is performed using the working connection 10-0.

Here, the present invention will be described by taking the communication from the ATM communication device 1 (1-1) to the ATM communication device (1-2) as an example. When setting up a connection, the ATM communication device 2 (1-2) on the receiving side has a line card 2 (3-2) containing a working connection.
The header conversion table 11 is set such that the same transmission header is attached to both the line card 3 (3-3) in which the protection connection is accommodated and the cell is transmitted. As a result, in the line card 1 (3-1), cells coming from both systems are mixed and transmitted.
However, in the 1: 1 redundancy configuration, since no user cell flows through the spare connection, only cells from the active system eventually arrive, so there is no problem. Sender AT
When the active system is switched from working to protection in the M communication device 1 (1-1), the ATM communication device 2 on the receiving side is switched.
In (1-2), since the cell is immediately transferred from the protection line card 3-3 to the line card 3-1 without performing the switching operation, the switching can be realized only by starting the transmission point.

A specific description will be given with reference to FIG.

The right connection will be described.
In this figure, the VC on the input side to the ATM communication device 1 (1-1)
The I (Virtual Connection Identifier) is a, the VCI of the working connection is b, the VCI of the protection connection is c, and the VCI on the output side from the ATM communication device 2 (1-2) is d.

At the time of connection setting, the line card 1 (3-1) of the ATM communication device 1 (1-1), which is the starting point of the 1: 1 redundant configuration, is, for example, disclosed in Japanese Patent Laid-Open No. 7-74747.
Working connection 1 by the method described in
The cell can be transmitted to either 0-0 or the protection connection 10-1. Then, on the receiving side, according to the method of the present invention, the ATM communication device 2 (1-
In 2), the header conversion table 11-2 of the line card 2 accommodating the working connection 10-0.
B is input VCI, d is output VCI,
1 indicating line card 1 (3-1) is set as the cell output route. In addition, protection connection 10-
1 is stored in the header conversion table 11-3 of the line card 3 accommodating the input VCI, the output VCI is d, and the line card 1 (3-
Set 1 to indicate 1). Thus, when the active system is switched to the protection connection in the ATM communication device 1 (1-1), the switching is immediately completed.

The above description has been made taking one-way switching as an example. However, in the case of using bi-directional switching, the above-described method is used for each bi-directional connection. Can be realized.

In this embodiment, the ATM communication device 1 (1
-1) and no communication device exists between the ATM communication device 2 (1-2), but other communication devices exist in the middle of each connection, such as when the working connection and the protection connection are respectively different networks. There is no problem that there is.

In this embodiment, the case where the input line card of the ATM communication apparatus 1 converts the ATM cell header is described. However, when the conversion of the ATM cell header is performed on the output line card, the output line card is also used. The present invention can be implemented by setting the header conversion table in the header conversion unit of the side line card so that the cell arriving from the working connection and the cell arriving from the protection connection are converted into the same cell header.

FIG. 9 shows the second object according to the present invention.
A method of transferring a specific cell when performing 1: 1 protection to a standby connection will be described. Here, an embodiment in which only a specific OAM cell is transferred to the standby system is shown.

ATM communication device 1 (1-1) as in FIG.
An ATM connection having a 1: 1 redundancy configuration is set between the ATM communication device and the ATM communication device (1-2). The invention for the first object described with reference to FIG. 1 is implemented in the ATM communication device 2 (1-2).

Input-side line card 1 of ATM communication device 1
(3-1) includes a header conversion table 11-1.
The header conversion table 11-1 includes a reception header, a transmission header for working and protection, and an active display. According to this table, the user cell is transferred to the working connection.

FIG. 10 shows a line card 3 having an OAM function.
The following shows an example of the configuration.

The line card 3 has an OAM processing unit. A
When a cell arrives from the TM SW2, the cell is first received by the I / O processing unit 90-o, and then sent to the transmission-side ATM layer processing unit 94-o. Transmission side ATM layer processing section 9
In 4-o, a header is cut out, and in the case of an OAM cell, it is sent to the OAM processing unit 91. In the case of a user cell, after processing such as acquisition of quality information, it is transferred to the transmission side physical layer processing unit 95-o. . Transmission side physical layer processing section 95-o
Then, after performing framing to a physical layer and electric-optical conversion, the data is transmitted to a transmission path.

When a cell arrives from the transmission path 7, the receiving side physical layer processing section 95-i first performs photoelectric conversion, takes out the cell from the physical layer frame, and the like.
This is sent to the TM layer processing unit 94-i. The receiving-side ATM layer processing unit 94-i performs quality information acquisition, header conversion, and the like, and then transfers the cell to the I / O processing unit 90-i. Then, the cell is transmitted from the I / O processing unit 90-i to the ATM SW2.

When transmitting an OAM cell, first, OA
The OAM processing unit 91 generates an M cell, and when the receiving-side ATM layer processing unit 94-i notifies that the empty cell has arrived, the OAM cell is converted to the receiving-side ATM layer processing unit 94-i.
-Forward to i. At the same time, it instructs the receiving-side ATM layer processing unit 94-i to transmit the OAM cell.
The receiving-side ATM layer processing unit 94-i selects a transmission header in accordance with the instruction and transfers the cell to the working connection or the protection connection.

FIG. 11 shows a detailed configuration of the transmitting side ATM layer processing section 94-o and the receiving side ATM layer processing section 94-i according to the present invention.

When transmitting an OAM cell, the OAM cell transmission request generation section 134 creates an OAM cell, and then waits for an empty cell arrival notification from the reception side header analysis section 135. When there is an empty cell arrival notification, the connection number is set in the connection number register 136 on the receiving side, and either transmission system is instructed to the header conversion 137 from working / protection. In the header conversion 137, the transmission side header is read based on the value of the reception side connection number register 136, and the OAM cell transmission request generation section 134
Add a header for sending cells to the system specified by. Then, the data is transferred to the I / O processing unit 90-i.

FIG. 12 shows the receiving-side ATM layer processing section 94-.
5 shows a flowchart of the operation i. When the cell transmission timing comes (41), first, the header analysis unit 135 analyzes the header. If the user cell is received, the cell header is cut out (43), and the connection number is extracted from the reception CAM 139. (44) Set in the connection number register 136 on the receiving side. Then, based on the connection number stored in the reception-side connection number register, the transmission-side cell header and the active system display are read from the reception-side RAM 141, and the cell header is added according to the readout (4).
5) (46) (49). Then, the cell is transmitted (47).

A flow for transmitting an OAM cell will be described. When an empty cell is received (42) and there is an OAM cell that needs to be transmitted (50), the connection number is set to the connection number on the receiving side, and then the receiving RAM 14 is set.
1 and a transmission header is added to the OAM cell by selecting a system according to the transmission system selection information (5).
3) After (54) and (55), the cell is transmitted (47).

In this embodiment, an OA for transmitting an OAM cell
The method in which the M processing unit 91 specifies the destination system to the receiving-side ATM layer processing unit 94-i has been described. The selection of the transmission destination may be performed by, for example, the receiving-side ATM layer processing unit. Specifically, the cell type is recognized from the header of the ATM cell, and the route is sorted according to the cell type. OAM
In the cell, for example, a cell related to switching is transmitted to the protection connection side.

In FIG. 9, working connection 1
0-0, the protection communication 10-1 is transmitted to the ATM communication device 1 on the transmitting side by using cells having respective applications.
The method of sending from (1-1) has been described. On the other hand, the ATM communication device 2 (1-2) on the receiving side identifies the cell branched to the working connection 10-0 and the protection connection 10-1 by the ATM communication device 1 (1-1) on the transmitting side. You have to choose. In the figure, cells arriving at the ATM communication device 2 (1-2) from both connections are input from the line card 2 (3-2) and the line card 3 (3-3), respectively. If the cell arriving from the standby system is terminated by the line card 2 (3-2) or 3 (3-3) on the input side, there is no problem of identification, but the line card 1 (3-1) on the output side. 1, the cells arrive from the working connection 10-0 and the protection connection 10-1 in a mixed manner, as described with reference to FIG. In this case, the line card 1 (3
In -1), it is necessary to identify which of the two connections the cell has arrived from. An embodiment of this identification method will be described with reference to FIGS. 9, 13, 14, and 15.

The outline of the process will be described with reference to FIG.

The input line card 2 (3-2) and the line card 3 (3-3) have a header conversion function, and add a device internal cell header and an output cell header according to the input cell header. An identifier on the input side is assigned to this cell header area inside the device, and is sent to the output side line card.
On the basis of the identifier on the input side, the output-side interface card identifies a cell coming from the working connection or a cell coming from the protection connection, and performs a process corresponding to each. The identifier may be, for example, a line card number.

FIG. 13 shows an internal cell format.

In this figure, the upper 4 octets are the in-device header 80 and the lower 53 octets are the ATM cell 81. In the ATM cell area, the upper 5 octets are the cell header,
The lower 48 octets are the ATM cell payload. The in-device header 80 has a routing flag (RTG) 83 indicating an output route, and the ATM SW 2 transfers the cell to the output route according to the routing flag (RTG) 83. The input side line card number 84 is provided in this internal header area. Then, after the input side line card assigns its own card identifier, the output side line card identifies, by the identifier, whether the cell has arrived from the working connection or from the protection.

FIG. 14 shows the operation at the time of cell reception in the transmission side ATM layer processing section 94-o of the transmission side line card (3-1). FIG. 11 shows the configuration of the transmitting-side ATM layer processing unit 94-o.

First, when a cell is received (61), a cell header is cut out by the transmitting-side header analyzing unit 121 (62), a connection number is searched from the transmitting-side CAM 124 based on the cut-out header, and stored in the transmitting-side connection number register 122. (63). Also, information about each connection is extracted from the connection number stored in the transmission-side connection number register 122, and the OAM
The information is transferred to the cell type information analysis unit 128. Next, if an empty cell is received, the cell is discarded (64). Furthermore, O
The transmission-side header analysis unit 121 analyzes whether the cell is an AM cell (65), and if the cell is a user cell, transmits the cell (67).
If it is an AM cell, it is transferred to the OAM cell type information analyzer 128. In the OAM cell type information analyzing unit 128, the transmitting side R
Based on the cell information output from the AM 126, it is determined whether the cell has come from the active system or the standby system, and a process corresponding to that is performed. More specifically, if an AIS cell arrives from the standby system, it is determined that the standby system has been disconnected, and the standby system is closed. If an AIS cell arrives from the active system, the connection is switched to the standby system. Is considered.

FIG. 15 shows the transmitting side CAM 124 and the transmitting side R.
A table configuration example in the AM 126 will be described. Sender C
In the AM 124, the connection number 161 can be derived from the input VCI 160 of the cell. From the connection number 161, it is possible to know where in the transmission side RAM 126 information about the connection of the cell is stored. The transmission-side RAM 126 stores input-side line card numbers 162 and 163 each containing a working connection and a protection connection as connection information. Further, an active system display indicating which is the active system is also stored. By comparing the value stored in this table with the input line card number mapped to the cell, it is determined whether the cell has come from the working system or the protection system, or whether the cell is in the working connection cell or protection. Whether the cell is a connection cell can be known from the output line card.

In the above-described embodiment, the processing of selecting each system for the OAM cell has been described. However, the present invention can be applied to, for example, identification of a working cell and a protection cell of a connection having a 1 + 1 type redundant configuration. When the user cell arrives, the cell can be selectively output by passing the cell if it arrives from the active system and discarding the cell if it arrives from the standby system. In the embodiment of FIG. 9, a field for identifying whether the cell is a working connection cell or a protection connection cell is provided in the internal cell header area of the device internal cell. Next, an embodiment in which an identifier for identifying a cell of a working connection or a cell of a protection connection is provided in an ATM cell header area will be described.

At the transmission-side branch point of the redundant configuration connection,
A cell to be transmitted through the working connection or a cell to be transmitted through the protection connection is mapped in an area of the ATM cell header and transmitted to each connection. The receiving side identifies from this information whether it came from a working connection or a protection connection. FIG. 16 shows an ATM cell (OAM type is only OAM cell). An area indicating a working or protection connection is provided in, for example, a PT field.
Thereby, the receiving side can recognize that this cell has arrived from the working or protection connection. In the case of an OAM cell, this value may be mapped to the OAM cell type field to identify the OAM cell.

With this method, 1: 1 switching can be realized. This is applicable not only to switching between termination points, but also to switching of a segment which is a part of a connection. FIG. 17 shows an application example.

ATM communication device 1-1 and ATM communication device 1
A VC10 is extended between the ATM communication devices 1-1 and 1-3, which are working segments and protection connections 10-2 between network termination points, respectively. Each has a working connection and a protection connection at the segment level. Here, the signals from the ATM communication devices 1-1 to 1-2 are considered. A
The input line card of the TM communication device 1-1 holds a selection table for storing an output header in the input line card. This table has a three-way output header and a switching function, and outputs the data to a three-way working connection. I do. At the junction of the working connection and the protection connection, cells arriving from both connections can be output by the method shown in FIG. As a result, the switching of the connection segment level can be realized only by the switching of the transmission point.

[0056]

As described above, according to the present invention, switching of an ATM connection having a 1: 1 redundant configuration can be easily performed, and communication between protection end points through a protection system can be easily performed. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of an ATM communication apparatus accommodating an ATM connection having a 1: 1 redundant configuration and a specific example of a function allocation method according to the present invention.

FIG. 2 is a diagram illustrating an example of a redundant configuration of a connection in conventional communication.

FIG. 3 shows ITU-T recommendation G. S shown in 783
It is a figure showing the functional model of protection in DH.

FIG. 4 is a diagram showing an example of a conventional ATM communication device for transferring information at various places by a fixed-length packet.

FIG. 5 is a diagram showing a configuration example of a line card in a deployment system of the ATM communication device shown in FIG. 3;

FIG. 6 is a diagram illustrating an example of a configuration of a portion that processes an ATM layer of the line card illustrated in FIG. 5;

FIG. 7 is a diagram showing an example of a table configuration of a portion for processing an ATM layer in a method of switching an output route in a conventional transmitting device.

FIG. 8 is a diagram showing an example of a processing flow of a portion for processing an ATM layer in a method of switching an output route in a conventional transmitting device.

FIG. 9 is a diagram showing an example of an ATM communication apparatus for performing a method of communicating control cells using a standby system of an ATM connection having a redundant configuration according to the present invention.

10 is a diagram illustrating an example of a line card of an ATM communication device that performs a method of communicating control cells using a standby system of an ATM connection having a redundant configuration illustrated in FIG. 9;

11 is a diagram illustrating an example of a configuration of a portion that processes an ATM layer in the line card illustrated in FIG. 10;

12 is a flowchart showing an example of the operation of the receiving-side line card of the transmitting-side ATM communication device of the system for communicating control cells using the redundant system of the ATM connection having the redundant configuration shown in FIG. 9; .

FIG. 13 shows a method of communicating control cells using a standby system of an ATM connection having a redundant configuration shown in FIG.
FIG. 3 is a diagram showing an example of a cell format used in a receiving-side ATM communication device.

FIG. 14 is a flowchart showing an example of the operation of the receiving-side line card of the receiving-side ATM communication device of the system for communicating control cells using the standby system of the ATM connection having a redundant configuration shown in FIG. .

FIG. 15 shows a receiving side A of a method of communicating control cells using a standby system of an ATM connection having a redundant configuration in FIG.
FIG. 3 is a diagram showing an example of a configuration for implementing a table for storing connection information of a receiving-side line card of a TM communication device.

FIG. 16 is a diagram showing an ATM cell format.

FIG. 17 is a diagram showing one embodiment of the present invention in a network provided with protection for connection segments.

[Explanation of symbols]

 1-1 to 1-4 ATM communication device 2 ATM switch 3-1 to 3-3 line card 4 control unit 7-1 to 7-n transmission line 8 control system transfer line 10 VC 10-0 working VC 10-1 protection VC

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor ▲ Taka ▼ Masahiro Tori 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture, Ltd.Information and Communication Division, Hitachi, Ltd. (72) Inventor Hiroshi Ota 3-chome Nishishinjuku, Shinjuku-ku, Tokyo 19-2 Nippon Telegraph and Telephone Corporation (72) Inventor Nobuyuki Tokura 19-2 Nippon Telegraph and Telephone Corporation 3-chome Nippon Telegraph and Telephone Corporation, 3-19-2 Nippon Telegraph and Telephone Corporation (72) Inventor Yoshio Kajiyama Nippon Telegraph and Telephone Corporation, 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo

Claims (11)

[Claims] 1. A network comprising a plurality of packet communication devices, one working connection and one protection connection, a user signal flowing through the working connection, and a protection connection through the protection connection. In a system switching method for a connection having a 1: 1 redundant configuration in which no user signal flows, a packet communication device serving as a receiving end point of a working connection and a protection connection is a header of a working connection and a protection connection. By setting the header conversion so that the same header is added and output in advance when setting the connection, the output system can only be changed in the packet communication device that becomes the branch point of the active and standby connections when switching the system. The signal flow can be changed from working to backup connection A system switching method for packet connections characterized by the following. And a packet switch for distributing an input packet from each of the input ports to one of the output ports determined by header information. The input port has a packet header conversion function. In an asynchronous transfer mode communication device equipped with a communication device, a user signal normally flows through a working connection and a user signal does not flow through a backup connection. In the cell header area, an identifier for identifying an active connection and a backup connection is provided, the identifier is provided at a start point constituting a redundant configuration, and the identifier is referred to at an end point, so that the receiving side is asynchronous. Incoming packet coming from working or protection connection in transfer mode communication device System switching method for a packet connection to said identifying and. 3. A packet connection switching method according to claim 2, wherein, when the starting point for configuring the redundant configuration is used, the fact that the connection is a working or protection connection is described in the header area of the packet on the input side interface. A method of switching a packet connection system, characterized in that 4. The method according to claim 2, wherein when a connection having a 1 + 1 redundant configuration is received, the line card on the transmitting side uses the active or standby connection according to the identifier of the working or protection connection. A method of switching a packet connection system, wherein a user cell arriving from a connection is passed, and a user cell arriving from a backup connection is discarded. 5. A packet conversion device comprising: a plurality of input / output ports; and a packet switch for distributing an input packet from each of the input ports to any one of the output ports determined by header information. Section and a working connection 1 in which a user signal normally flows.
In the asynchronous transfer mode communication apparatus accommodating at least one set of connections in the asynchronous transfer mode area having one redundant configuration in which no user signal flows, at the input port of the asynchronous transfer mode apparatus on the transmission side,
A header for holding an output header for the input header, a working output and a spare for the input header, assigning a working output header to a user cell, and assigning a spare output header to a specific cell and inputting the packet to the packet switch. The packet switch transmits a user cell to an opposite asynchronous transfer mode communication device through a working connection based on a header provided by the header converting means, and a specific cell is used as a spare cell. An asynchronous transfer mode communication device for transmitting through a connection. 6. The asynchronous transfer mode communication device according to claim 5, wherein a specific OAM packet is transmitted to a spare connection, and the other cells are transmitted to a working connection. apparatus. 7. The asynchronous transfer mode communication device according to claim 5, wherein said header conversion means assigns a current output header to a user cell, and assigns a spare output header to a specific cell, Input to the packet switch, wherein the packet switch transmits a user cell to an opposite asynchronous transfer mode communication device through a working connection based on the header provided by the header conversion means. Communication device. 8. A plurality of input / output ports, and a packet switch for distributing an input packet from each of the input ports to one of the output ports determined by header information, wherein the input port converts a packet header. Normally, the user signal is flowing through the working connection and the user signal is not flowing through the protection connection 1: 1 or 1 + 1 where the user signal is flowing through both the working connection and the protection connection. In an asynchronous transfer mode communication device accommodating at least one set of connections in an asynchronous transfer mode having a redundant configuration, the input port includes an identifier for identifying a working or a spare of the connection having the redundant configuration inside the device. The current header and the spare connection are used. An asynchronous transfer mode communication device, wherein a packet is received from a working or protection connection by referring to the identifier at the output port. 9. The asynchronous transfer mode communication device according to claim 8, wherein the input port has an identifier for identifying a working or a spare of a connection having a redundant configuration in a header portion used in the device, and the working port and the spare port are used. An asynchronous transfer mode communication device, characterized in that an identifier is assigned to each connection for communication. 10. The asynchronous transfer mode communication device according to claim 8, wherein the output port determines whether the cell has come from the working or the protection from a working protection identifier, and An asynchronous transfer mode communication device, which performs a process according to each of arrivals from a backup. 11. An asynchronous transfer mode communication apparatus according to claim 8, wherein when a connection having a 1 + 1 redundant configuration is received, the transmitting side line card determines the working connection according to the identifier of the working or protection connection. An asynchronous transfer mode communication apparatus, comprising: a transmitting-side ATM layer processing unit that passes user cells arriving from a backup connection and discards user cells arriving from a backup connection.