JPH04230142A - Connection-less data exchange system - Google Patents

Abstract

PURPOSE:To attain the confirmation of a connection-less data transfer service in an ATM exchange. CONSTITUTION:A terminal equipment 6 is connected to an ATM switch 4 via a line module 10 and a cell sent from the terminal equipment 6 is transferred to a connection-less module 16 for the processing. In this case, a virtual band between plural connection-less modules 16 connected to other terminal equipment and a connected physical line number are made variable depending on the communication function between the call control module 14 connecting to the ATM switch 4 and the connection-less module 16. Thus, plural connection-less modules are set in the network to reduce one connection-less module without giving effect onto the user network interface. Moreover, priority is placed on virtual channels among the connection-less modules to allow the system to cope with congestion or the like.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connectionless data exchange system in an ATM switching network.

0002

[Prior art] AT as a next-generation communication network
Wideband ISD using M (asynchronous transfer mode) switching method
Research on N (Comprehensive Service Digital Network) is being actively conducted both domestically and internationally. As a target of this service, L
Connections between ANs (Local Area Networks) and MANs (Metropolitan Area Networks), and connections between these networks are being considered. Documents related to such switching systems include ``Study of ATM and MAN Adaptation Functions for LAN Connections'' (Switching System Study Group, SSE89-40), ``LAN and MAN
``Proposal of an interconnection method'' (Information Network Study Group,
IN89-66) etc.

According to these documents, there are two types of services provided by ATM switching networks: connection type (hereinafter referred to as CO type) and connectionless type (hereinafter referred to as CL type).
There is. In CO type service, when setting up a call, a virtual channel is set up from one user/network interface to the other party's user/network interface, and in this case, a virtual channel identifier (VCI) is added to the cell and transferred. It is configured to release the connection when communication ends. In this case, virtual channel setting methods include a switching type using call control signals and a semi-fixed type in which channels are set in advance.

[0004] The upper LAN and ATM switching network are
Connected via an O-type adaptation layer. In this case, variable length CL type data in the LAN is assembled and disassembled into segment type first cells, middle cells, last cells or single cells. A message identifier indicating the same CL cell is added to the segment type cells.

[0005] Like the CO type service, the CL type service includes an adaptation layer, and assembles and disassembles variable-length CL data into the first cell, middle cell, last cell, or single cell of the segment type. A message identifier indicating the same CL cell is added.

[0006] This CL type service differs from the CO type service in that it does not establish or open a channel between the CO type user and the network interface, but directly transfers data to the ATM switching network. Furthermore, this CL type service is a method that does not perform data order control, erroneous control, or flow control. As for hardware, a CL service module is provided within the ATM switching network. CL data cells are transferred to the CL service module via the CL virtual channel. The CL service module is
E of the first cell. 164 Create a routing table based on addresses and message identifiers, and select routes for cells with the same message identifier by searching this table. A convergence function common to CO type and CL type services is used to identify the upper protocol in the adaptation layer and indicate the size of the upper data.

[0007]

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, there are problems with the method of transferring cells to the CL service module in the exchange, the method of transferring cells between modules, and the load caused by installing a plurality of CL service modules. The distribution method and the method of establishing a virtual channel for cell transfer on the user/network interface were unclear. Therefore, it was necessary to establish these methods in order to realize an ATM switch.

The present invention solves the problems of the prior art, clarifies the cell transfer method, load distribution method, and virtual channel establishment method, and provides a connectionless system that can contribute to the realization of an ATM switching network.・The purpose is to provide a data exchange method.

[0009]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a connectionless data exchange system in an ATM switch that transfers cells having a channel identifier via an ATM switch.・The network interface accommodates a terminal that inputs variable-length connectionless data from the user side and fixed-length cells from the network side, converts them to each other, and outputs them.
A terminal connecting means is connected to the M exchange and converts the channel identifier of each cell on the terminal side and the exchange side, and a terminal connecting means is connected to the ATM switch and converts the channel identifier of each cell on the line side and the exchange side. trunk means, connectionless data transfer means connected to an ATM switch for inputting data cells through the ATM switch, converting channel identifiers of these cells, and transferring the data cells to each destination means; It is connected to an ATM switch and receives a signal cell containing a call connection request, analyzes its contents, and transmits the data between each means on the transfer path of the data cell between the calling and receiving terminals and the ATM switch to the ATM switch. The device is characterized in that it is connected to a call control means that sets a virtual channel for transfer and notifies each means of the channel identifier.

0010

[Operation] According to the connectionless data exchange system according to the present invention, an ATM switch includes terminal connection means for connecting a connectionless terminal to the ATM switch, trunk means for connecting a trunk line, call control means, and Connectionless data transfer means are respectively connected to establish a connectionless service with each of these means. In this case, the communication function between the call control means that sets up a virtual channel and the connectionless data transfer means that transfers cells between modules via an ATM switch makes it possible to connect multiple connectionless data transfer means. Become. Therefore, in response to the load of connectionless services, multiple physical lines and virtual channels are set up within and between ATM exchanges to establish load distribution.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of a connectionless data exchange system according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a connectionless system according to the present invention.
1 is a relay system diagram showing an embodiment of an ATM switch to which a data exchange system is applied; FIG. In this figure, the ATM switch of this embodiment performs switching processing in the asynchronous transfer mode.A line A to which a terminal 6 is connected is connected to an ATM switch 4 that performs switching processing in the asynchronous transfer mode.
and line module (CIM) 1 that accommodates line C.
Trunk module (TM
) 12 , a call control module (CM) 14 ,
A connectionless module (CLSM) 16 is connected to transfer cells between each module to realize connectionless data transfer.

[0013] The terminal 6 corresponds to an adaptation layer interposed between the upper layer LAN and ATM layer of the OSI model shown in FIG. These terminals 6 are
When connectionless (CL) data to be transmitted from the LAN to the ATM network is input, the data is divided into ATM cells, and the ATM cells are assembled into CL data. The terminal 6 decomposes the destination address and variable length data of the CL data into predetermined length data, and adds the same message identifier MID and segment type ST indicating which part of the CL data each data is to this data. do. This data is used as the information part, a header is added to it, and it is converted into a fixed-length ATM cell. The header of an ATM cell includes a virtual channel identifier corresponding to a channel between modules, and the information section includes signal or CL data, which form a signal cell or a data cell, respectively.

The line module 10 and the trunk module 12 each convert the virtual channel identifier of a cell input via the lines A, C or the trunk line B into a virtual channel identifier inside the exchange. This prevents the occurrence of identical virtual channel identifiers.
The ATM switch 4 takes into account the connection of a plurality of line modules 10 and converts the cell identifier into a unified virtual channel identifier between modules, and if the cell is a signal cell having a signal virtual channel identifier, Transfer to call control module (CM) 14. If the cell is a data cell whose virtual channel identifier is for information, the ATM switch 4 transfers it to the CL module 16 .

Call control module 14 assembles and analyzes signals from cells of signaling virtual channel identifiers. If it is a connection setup and release signal, it notifies the line module 10, ATM switch 4, and CL module 16, which will be described later, of the setup and release of the virtual channel of the data cell, and sends a confirmation signal to the terminal.

The line module 10 and the trunk module 12 convert the virtual channel identifier of a cell having a virtual channel identifier for CL data transfer, and then transfer the cell to the ATM switch 4. A.T.
Since the M switch 4 has been notified of the cell transfer from the call control module 14, it passes the cell to the CL module 16.

The CL module 16 is a module that transfers data cells having a virtual channel identifier for CL data transfer between the line module 10 and trunk module 12, and transfers data cells between ATM exchanges.

FIG. 2 shows the C in the ATM switch in FIG.
FIG. 2 is a diagram for explaining channel settings for L-type service. In this figure, when the terminal 6 makes a call, a virtual channel identifier is sent between the terminal 6, the line module 10, the ATM switch 4, and the call control module 14 as "X".
, "Y", and "Z" are set. The call for CL data transfer from the terminal 6 is notified to the call control module 14 via this signal channel.

The call control module 14 communicates between the ATM switch 4 and the CL module 16 by using a communication channel with a virtual channel identifier "α" that is assigned at the time of system initialization. A signal channel with "β" and "γ" is set to instruct the transfer of CL data cells of the terminal 6, and the terminal 6, the line module 10, and the ATM
The setting of data transfer channels with virtual channel identifiers "a", "b", and "c" is instructed between the switch 4 and the CL module 16, respectively. Data cells are transferred from the terminal 6 to the CL module 16 through these channels, and from the module 16 to the terminal 6 or trunk module 12.

FIG. 8 shows a sequence for transmitting and receiving signal cells and setting a data channel in the ATM switch of this embodiment. The terminal 6 adds a header with a virtual channel identifier "x" and sends out a signal cell 41 specifying a virtual channel carrying CL data as the signal content. The line module 10 converts the virtual channel identifier "x" of this cell into a virtual channel identifier "y" inside the exchange, and adds information such as a line number indicating that the signal is sent from the terminal 6. 42.

The ATM switch 4 receives the cell 42, converts the cell 43 into a virtual channel identifier "z" between the connected modules, and transfers the cell 43 to the call control module 14. This causes the call control module 14 to
We know that we want to transfer CL data from , and use "a" as the virtual channel identifier for the channel of the same data. The call control module 14 sends out a signal cell 44 via the ATM switch 4, and sends out a cell 45 from the ATM switch 4 to the line module 12. For instruction information and CL data cells, the space between the terminal 6 and the line module 12 to the CL module 16 is designated as "a", and the space between the CL module 16 and the ATM switch 4 is designated as "b". Response confirmation cells 46 and 47 are returned in response to this cell transmission.

Similarly, the call control module 14 and the ATM
The cells 48 and 49 issue an instruction to send the cell with the virtual channel identifier "b" as a cell with the virtual channel identifier "c" and confirm the response with the switch 4. From the call control module 14 via the ATM switch 4,
To the CL module 16 Cells 50 to 5 for instructing and response confirmation that the virtual channel identifier of the data cell between the ATM switch 4 and the CL module 16 is "c"
3 is exchanged. Cells 54 to 56 are sent from the call control module 14 to the ATM switch 4 and terminal 6 to confirm a response to a request to set the virtual channel identifiers of data cells to "a" and "b". Data cell 6 from terminal 6 to CL module 16 via ATM switch 4
0, 61, 62 are sent.

FIG. 3 shows data cell transfer routes of ATM switches 70 and 72. A virtual channel is established between exchanges prior to transferring CL data. In FIG. 6, the exchange 70 sends a signal cell requesting virtual channel identifier setting for a CL virtual channel from the CL module 16 to the call control module 14. The call control module 14 requests the call control module 24 of the exchange 72 to set a virtual channel identifier, and the module 24 requests the call control module 24 of the exchange 72 to set a virtual channel identifier.
The L module 26 is notified of the virtual channel identifier setting. Call control module 24 from the same module 26
, 14 and the CL module 16, a signal cell indicating completion of virtual channel identifier setting is sent to the CL module 16. In FIG. 3, CL data is transferred between terminals 6 and 27 via route 100,
102, and between the terminals 6 and 28, the route 100,
104 and 106. ATM switch 7
It is also possible to set up multiple virtual channels by using multiple physical lines between 0 and 72.

FIG. 4 shows multiple paths between CL modules. The route 120 passes through the ATM switch 74 and sets the virtual channel identifier to "e".
The virtual channel identifiers are set to "f" and "g" via the ATM switch 78. CL module 16,
26 is a virtual channel identifier VCI corresponding to the channel (VC) according to the management table 200 in FIG.
Select the priority.

There are two types of CL virtual channels in the user/network interface: semi-fixed type and switched type. In the data cell transfer path of the terminal in Figure 5, the semi-fixed type is
Data cells are sent from the terminal 6 using the virtual channel identifier determined at the time of terminal connection. In the switched type, call setting cells and call acceptance confirmation cells are exchanged with the network and data cells are transferred via the CL module 16 according to the general call setting sequence shown in FIG. In the switched type, in this way, for each call, the terminal sends the service type (connectionless), the desired virtual channel VC for communication, and the desired band to the call control module 14 using the call setup signal format 202 shown in FIG. The call acceptance signal 204 is used to receive a virtual channel identifier that identifies a data channel.

In FIG. 4, when a CL data cell destined for a called terminal arrives at the CL modules 16 to 26 and a virtual channel for CL data transfer is not established between the CL module 26 and the terminal, Call setup cell 2 in Figure 11
06 is sent from the network to the terminal. The cell includes a virtual channel identifier for identifying CL communication and CL data size as service types. A call acceptance cell is returned from the terminal, and the CL module sends a CL data cell using the virtual channel.

In FIG. 3, the originating terminal establishes a CL virtual channel using the above semi-fixed type and switched type methods. CL data is transferred via route 10 between terminals 6 and 27.
0, 102, and route 10 is used between terminals 6 and 28.
0, 104, 106.

[0028]

[Effects of the Invention] As explained above, according to the present invention,
A connectionless service can be provided by connecting a terminal connection means for connecting a terminal to an ATM switch of an ATM exchange, a trunk means for connecting a trunk line, a call control means, and a connectionless connection means. In this case, the communication function between the call control means that sets up a virtual channel and the connectionless connection means that transfers cells between modules via an ATM switch,
Connection of multiple connectionless connection means becomes possible. Therefore, a plurality of physical lines and virtual channels can be set within and between exchanges in accordance with the load of CL services, so that flexible CL services can be provided. Further, depending on the call volume of the terminal, semi-fixed type and switched type virtual channels can be set up between the terminal and the exchange.

[Brief explanation of the drawing]

FIG. 1 is a relay system diagram showing an embodiment of an ATM switch to which the connectionless data exchange system of the present invention is applied.

FIG. 2 is a relay system diagram for explaining virtual channels in the ATM switch of FIG. 1;

FIG. 3 is a relay system diagram for explaining a data cell transfer path of an ATM switch in an embodiment of the present invention.

FIG. 4 is a relay system diagram for explaining route selection between collectionless modules in the embodiment of the present invention.

FIG. 5 is a relay system diagram for explaining a data cell transfer path of a terminal in an embodiment of the present invention.

FIG. 6 is a signal diagram for explaining an exchange type signal format in an embodiment of the present invention.

FIG. 7 is a data configuration diagram for explaining the conversion between connectionless data and ATM cells in the embodiment of the present invention;

FIG. 8 is a signal diagram for explaining virtual channel settings within an exchange in an embodiment of the present invention.

FIG. 9 is a signal diagram for explaining virtual channel setting between exchanges in an embodiment of the present invention.

FIG. 10 is a configuration diagram showing signal formats in an embodiment of the present invention.

FIG. 11 is a diagram showing the format of a call setup signal in an embodiment of the present invention.

[Explanation of symbols]

4, 34 ATM switch 6, 27, 28 Terminal 10, 18, 20 Line module 12, 22 Trunk module 14, 24 Call control module 16, 26 Connectionless module 70-7
8 ATM exchange machine

Claims (4)

[Claims] Claim 1: Transfer cells with channel identifiers via an ATM switch. In a connectionless data exchange system in an ATM switch, variable-length connectionless data on the user side is transferred to the user-network interface of the ATM switching network. It accommodates a terminal that inputs fixed-length cells from the network side, converts them, and outputs them.
The ATM switch includes a terminal connecting means connected to the ATM switch to convert the channel identifier of each cell on the terminal side and the exchange side, and a terminal connecting means connected to the ATM switch to convert the channel identifier of each cell on the line side and the exchange side. trunk means connected to said ATM switch and said A
connectionless data transfer means that inputs a data cell via a TM switch, converts the channel identifier of the cell, and transfers the data cell to each destination means;
Connected to the TM switch to receive a signal cell containing a call connection request, analyze its contents, and transfer data between each means on the data cell transfer path between the calling and receiving terminals and the ATM switch. 1. A connectionless data exchange system, comprising call control means for setting up a virtual channel for a virtual channel and notifying the respective means of the channel identifier of the channel identifier. [Claim 2] The connectionless system according to claim 1.
In the data exchange system, when each of the means is connected to the ATM switch, a channel identifier of a signal channel to be transferred is provided between each of the means for transferring signal cells and between each of the means and the ATM switch. Set it and
A semi-fixed type in which, when a terminal and a line are connected to the ATM switch, a virtual channel for data transfer is semi-fixed by the signal channel between the terminal and line and each means for transferring data cells; A connectionless data exchange method characterized by having a channel. [Claim 3] The connectionless system according to claim 1.
The data exchange system is characterized in that a switched channel is provided between the terminal and the line and each means for transferring data cells, which is set up by the signal channel each time a data transfer virtual channel is called. Connectionless data exchange method. [Claim 4] The connectionless system according to claim 1.
In the data exchange method, the ATM switch is connected to a connectionless data transfer means for transferring cells between modules via the ATM switch, and a call control module that connects a plurality of trunk lines to establish a virtual channel. A connectionless data exchange system characterized in that a plurality of virtual channels for data transfer are set up within an ATM exchange and between other exchanges via the connectionless data transfer means.