JPH0360246A - Asynchronous transfer mode communication device - Google Patents

Abstract

PURPOSE:To execute the exchange process of a cell at a high speed by controlling a logic channel and a cell based on logic channel discrimination information and cell discrimination information indicated in an information cell. CONSTITUTION:An asynchronous transfer mode cell (cell) on user-network interfaces 12, 13 and inter-station interfaces 19, 21 is constituted of a header field 31 and an information field 32. The information field 32 is constituted so as to store sending data, and besides, the header field 31 is constituted of a call identifier 33, a logic channel identifier 34 and other control information. Since the call identifier 33 and the logic channel identifier 34 are indicated in the header field 31 of the cell, call control and logical channel control are separated from each other. Thus, the exchange process of the cell can be executed at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an asynchronous transfer mode communication device that performs control using a call identifier and a logical channel identifier.

[Conventional technology]

Asynchronous transfer mode (ATM) communication, recommended by the Consultative Committee on International Telegraph and Telephone (CCITT), has been proposed and considered as a candidate for next-generation transmission systems. This asynchronous transfer mode communication is different from either conventional circuit-switched or packet-switched communication.

In the case of circuit-switched communications, the time slots on the highway are time-division multiplexed, and one call occupies a time slot at a predetermined time position in each fixed frame, which typically has a period of 125 microseconds. The calling side channel and the called side channel determined by the control signal are connected by hardware.

In addition, in packet-switched communication, variable-length packets of up to 4,000 bytes are sent and received, and packets are exchanged within the network using software based on the contents of call control packets and the logical channel number of data transfer packets. .

On the other hand, in asynchronous transfer mode communication, the exchange itself is performed by hardware as in circuit switched communication. However, unlike circuit-switched communications, highways transmit information in a type of packet called a cell, which typically has a fixed length of 40 to 120 bytes. This is also different from conventional packet switching communication, which uses variable length packets, in that information is transferred using fixed length packets.

In this case, the cell position on the highway is determined, and only when information to be sent is generated, identification information called a logical channel identifier (VCI) is added to the information, put into a cell, and sent out. This logical channel identifier is used to identify which logical channel each cell is associated with. Further, this cell becomes an empty cell when there is no information.

In such asynchronous transfer mode communication, a single physical channel is not occupied by a single call, but a virtual logical channel is provided to the call, so that a single physical channel or physical transmission path is associated with one or more calls. Can be shared by multiple logical channels.

Therefore, a call and a logical channel are a unit of communication.
There are cases where it does not correspond to one-to-one. For example, there are cases where a plurality of logical channels are associated with one call, or cases where a plurality of logical channels are associated serially within one call, such as when switching media during communication. This is expected to become more and more prominent in the future as the demand for multimedia communications and advanced communications increases.

In this way, if calls and logical channels do not correspond one-to-one, call control and logical channel control also do not correspond one-to-one. If one of the calls is to be disconnected, only that logical channel needs to be disconnected, but if the call itself is to be disconnected, all related logical channels must be disconnected.

Therefore, conventionally, each cell displays only a logical channel identifier, and a functional unit that processes the cell recognizes and determines the correspondence between calls and logical channels. That is,
For each call control, software searches for the correspondence between calls and logical channels, and the hardware is driven based on the results.

In addition, the logical channel identifier number band is separated for each call,
A method has also been used in which the call identification is implicitly indicated by the number of the logical channel identifier.

[Problem to be solved by the invention]

However, in asynchronous transfer mode communication, it is essential to process cells at high speed using hardware, and conventional search processing using software delays call control and reduces call control capability. was there.

Furthermore, in the method of separating calls based on the number bands of logical channel identifiers, it is not possible to clearly identify and separate logical channels and calls, resulting in mutual interference between logical channel control and call control. Therefore, there is a drawback that the independence of each control cannot be maintained.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an asynchronous transfer mode communication system that can separate call control and logical channel control and that can perform cell switching processing at high speed.

[Means to solve the problem]

In the present invention, (i> cell receiving means for receiving a cell including call identification information for identifying a call and logical channel identification information for identifying a logical channel; and (ii) call identification information included in this cell. An asynchronous transfer mode communication device is provided with a call identification means for identifying a call using information, and (iii) a logical channel identification means for identifying a logical channel using logical channel identification information included in a cell.

In the present invention, logical channels and calls are controlled based on the logical channel identification information and call identification information displayed in the information cells.

〔Example〕 Hereinafter, the present invention will be described in detail with reference to Examples.

FIG. 1 depicts an asynchronous transfer mode communication system in one embodiment of the present invention.

The system consists of an asynchronous transfer mode communications network 11 and first and second premises equipment 14.15 connected to it via a user-network interface 12.13. This asynchronous transfer mode communication network 11 consists of exchanges 16, 17, and 18, which are connected by an interoffice interface 19.21.

In the asynchronous transfer mode communication system configured as described above, the operation when transmitting data from the first home device 14 to the second home device 15 will be described.

The first in-home equipment 14 is connected to the user/network interface 12
When a call setup request is made to the asynchronous transfer mode communication network 11 via the asynchronous transfer mode communication network 11, the asynchronous transfer mode communication network 11 makes an incoming call request to the second home equipment 15 via the user/network interface 13. If the second home device 15 can receive the call, it sends a response to that effect to the asynchronous transfer mode communication network 11. Then, the asynchronous transfer mode communication network 11 notifies the first home device 14 on the calling side of this, and also confirms the response with the second home device 15 on the called side. As a result, the asynchronous transfer mode communication network 11 completes the connection between the first home device 14 and the second home device 15.

FIG. 3 shows the internal configuration of the first in-home device 14 in detail.

The insertion circuit 43 provided in this first home equipment 14 is
It is connected to the user information cell assembly/disassembly section 42 and the signal cell assembly/disassembly section 45 so as to adjust conflicts that occur when user information cells and signal cells output from these are sent to the user/network ink face 12. It has become. These user information cell assembly/disassembly section 42 and signal cell assembly/disassembly section 45 are also connected to a branch circuit 44, whereby cells input from the user/network interface 12 are divided into user information cells and signal cells. It is done manually. Furthermore, a control circuit 46 is connected to the user information cell assembly/disassembly section 42 and the signal cell assembly/disassembly section 45, and this controls cell assembly/disassembly in each cell assembly/disassembly section. It looks like this.

Further, a user information function section 41 is connected to the user information cell assembly/disassembly section 42, and user information is exchanged between them.

When the connection between the first home equipment 14 and the second home equipment 15 is completed in the process described above, the control circuit 46 displays a call identifier for identifying the call and all logical channels related to the call. Determine and store the logical channel identifier. Then, the determined call identifier and logical channel identifier are notified to the user information cell assembly/disassembly unit 42 via the control bus 48. The user information cell assembly/disassembly section 42 assembles a user information cell based on the call identifier, the logical channel identifier, and the user information to be transmitted inputted from the user information function section 41.

FIG. 2 represents the basic format of an asynchronous transfer mode cell (hereinafter simply referred to as a cell) on the user-network interface 12.13 and the inter-office interface 19.21.

This cell has a header field 31 and an information field 3.
The information field 32 is configured to contain data to be sent.

The header field 31 also includes a call identifier 33, a logical channel identifier 34, and other control information.

A cell with such a configuration is used in the user information cell assembly/disassembly section 42.
and sent to the user-network interface 12 via the insertion circuit 43.

On the other hand, when it becomes necessary to send some kind of control signal to the second home equipment 15, the signal cell assembly and disassembly section 45
A signal cell is assembled based on the control signal from the control circuit 46, a call identifier, and a logical channel identifier, and sent to the user/network interface 12 via the insertion circuit 43.

These user information cells and signaling cells sent out on the user-network interface 12 are input to the first exchange 6.

FIG. 4 shows the inside of the first exchange 16 in detail.

This first exchange 16 is provided with a cell exchange switch 54, the input side of which is connected to an input highway 57 via a header processing section 53 consisting of a logical channel identifier processing section 51 and a call identifier processing section 52. . This input highway 57 constitutes the user/network interface 12 (FIG. 1), and the output highway 59 on the output side of the cell exchange switch 54 constitutes the interoffice interface 19 (first
(Fig.).

Logical channel identifier processing unit 51 and call identifier processing unit 5
2 is connected to a control circuit 55 via a control bus 58. This control circuit 55 is configured to send a control signal to the logical channel identifier processing unit 51 when logical channel control is required, and to the call identifier processing v652 when call control is required.

When a cell having the format shown in FIG. 2 is input to the first exchange 16 at the bottom of the tank, it is first taken into the logical channel identifier processing section 51.

The logical channel identifier processing unit 51 searches for information instructed by the control circuit 55 at the time of logical channel setting, such as intra-switch routing information, based on the value of the logical channel identifier 34 in the header field 31 of the cell. , this is placed in a margin field within the cell as additional information for exchange, and is passed to the call identifier processing unit 52 together with the cell. For example, other areas in FIG. 2 may be used as this margin field, but additional information for exchange may be exchanged through a separately prepared control line.

The call identifier processing unit 52 searches for information instructed by the control circuit 55 at the time of call setup, such as call-specific priority information, based on the value of the call identifier 33 in the header field 31 of the cell. Then, if necessary, the additional information for replacement described above is replaced or supplemented, and if it is not necessary, the cell replacement switch 5 is left together with the cell as is.
Pass it to 4.

Then, in the cell exchange switch 54, the call identifier processing unit 5
From step 2, the receiver performs an exchange connection based on the received additional information for exchange.

Thereafter, in the same manner, after exchange connections are made by the second and third exchanges 17 and 18, this cell is inputted to the second home equipment 15 via the user/network interface 13.

The second home equipment 15 has exactly the same configuration as the first home equipment 14 described above, so here, FIG.
This will be explained by replacing it with a representation of the internal details of the home equipment 15.

From the user/network interface 13 to the second home equipment 15
Cells input to the branch circuit 44 are first input to a branch circuit 44, where they are distinguished into user information cells and signal cells. The user information cell is converted into the original user information form by the user information cell assembly/disassembly section 42 and sent to the user information function section 41 . Also,
Necessary signal information is extracted from the signal cell by a signal cell assembly/disassembly section 45 and sent to a control circuit 46 via a control bus 48. In this case, normally only the logical channel identifier 34 is used to restore the user information format, but if there is a particular instruction from the control circuit 46, call-by-call control is performed using the call identifier 33.

In this way, the cells sent out from the first home device 14 are taken into the second home device 15.

Note that, for example, in the first exchange 16, when requesting processing for all logical channels related to one call, the control circuit 55 requests the logical channel identifier processing unit 51 to process each logical channel. There is no need to send instructions that take into account the state of the logical channel for each identifier. That is, in this case, the control circuit 55 only needs to send an instruction to designate the call identifier 33 to the call identifier processing unit 52 once, without considering the state of each logical channel. This results in processing for all logical channels associated with this call.

〔Effect of the invention〕

As explained above, according to the present invention, call control and logical channel control can be separated by displaying a call identifier and a logical channel identifier in the header field of a cell, so that the logical configuration of a control circuit can be changed. This has the advantage that it is simplified and the cell exchange process can be performed at high speed.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings are for explaining one embodiment of the present invention, in which FIG. 1 is a block diagram showing an asynchronous transfer mode communication system, and FIG. 2 is a basic format of an asynchronous transfer mode cell. FIG. 3 is a block diagram showing the internal details of the household equipment, and FIG. 4 is a block diagram showing the internal details of the exchange. 11...Asynchronous transfer mode communication network, 12.13
・・・・・・User/Network Interface, 14.15・
...In-home equipment, 16.17.18...Switchboard, 19.21...
...Inter-office interface, 33...Call identifier, 34...Logical channel identifier, 4■...
・User information function unit, 42...User information cell assembly and disassembly unit, 43...
...Insertion circuit, 44...Branch circuit, 45.
... Signal cell assembly and disassembly section, 46 ... Control circuit, ... Logical channel identifier processing section, ...
Call identifier processing unit, ... cell exchange switch, ... control circuit.

Claims (1)

[Claims] Cell receiving means for receiving a cell including call identification information for identifying a call and logical channel identification information for identifying a logical channel; An asynchronous transfer mode communication device comprising: call identification means for identifying a call; and logical channel identification means for identifying a logical channel using logical channel identification information included in the cell.