JPS63238738A - Communication control device - Google Patents

Abstract

PURPOSE:To attain a mutual communication between a terminal for a line switching and a terminal for a packet switching and a mutual communication between terminals for the line switching having different speeds by executing a protocol converting or a data speed converting with a CPU and a data buffer. CONSTITUTION:In a mutual communication between a terminal 5 for a line switching connected to a communication control board 9 of a communication control device 3 or a mutual communication between the terminal 5 for the line switching through a line switching network 1 and a terminal 20 for the line switching, a speed converting is executed by the actions of a CPU board 6 and a memory 7 and a mutual communication between terminals having different speeds can be executed. In a communication between the terminal 5 for the line switching connected to the communication board 9 and a terminal 4 for a packet switching, with the actions of the CPU 6, the memory 7 and the communication control board 9, the conversion of a line switching protocol and a packet switching protocol is executed and a communication between the terminal for the line switching and the terminal for the packet switching can be executed.

Description

TECHNICAL FIELD The present invention relates to a communication control device, and more particularly to a communication control device capable of converting protocols between circuit switching and packet switching, and converting the line speed of circuit switching.

Conventional technologyIn circuit switching, which is a form of leased line or public line, one line is maintained until a series of data transmission/reception is completed, whereas in packet switching, terminals do not directly send and receive data to each other. , data transmission using store-and-forward is performed in packet units. In other words, the exchange temporarily stores the data information sent from the sending terminal in its memory, first selects an appropriate route within the network at high speed, and finally rearranges the packet sequence correctly and sends it to the other party's terminal. It is a method of delivering to. Therefore, no communication path is established between the terminals for directly transmitting and receiving data. Data information flowing within the network is divided into packets each having a predetermined length and a header containing destination information and the like added to each packet. The exchange performs processing on a packet-by-packet basis.

Packet-switched networks allow terminals with different communication speeds to communicate with each other, which is not possible with circuit-switched networks.

However, conventionally, terminals developed for packet switching and
Communication between terminals developed for circuit switching was not possible. In addition, with line switching, communication was possible only between terminals with the same line speed, so high-speed lines (for example, 48
It has been impossible to communicate between a terminal connected to a low-speed line (for example, 9600 BPS) and a terminal connected to a low-speed line (for example, 9600 BPS) due to insufficient processing capacity.

Purpose The purpose of the present invention is to improve such conventional problems and to enable communication between single circuit switching terminals and packet switching terminals, as well as communication between circuit switching terminals with different line speeds. The purpose of the present invention is to provide a communication control device that achieves the following.

Configuration To achieve the above objects, 1 the communication control device of the present invention is a communication control device connected to a line termination device of a line switch, which connects to at least one or more local circuit switching terminals and packet switching terminals. a first communication control means connected to the line termination device, a second communication control means connected to the local line switching terminal and packet switching terminal, and the first and second communication control means It has a data buffer interposed between them, and a CPU that controls the data buffer and the first and second communication control means, and the first communication control means includes a line switching protocol,
The second communication control means has a line switching protocol or a packet switching protocol, and the second communication control means has a line switching protocol or a packet switching protocol.
It is characterized by protocol conversion or data speed conversion using a data buffer.

Hereinafter, the configuration of the present invention will be explained in detail using examples.

FIG. 1 is a system diagram of a switching network showing one embodiment of the present invention.

In FIG. 1, 1 is a circuit switching network and an exchange, 2 is a circuit termination device, 3 is a communication control device according to the present invention, 4 is a packet switching terminal, and 5 and 20 are circuit switching terminals. In this embodiment, when the circuit switching terminals 2o and 5 are connected via the circuit switching network and the exchange 1, the present invention is applied between one of the circuit switching terminals 5 and the circuit termination device 2. Insert the communication control device 3, and this communication control device 3
A plurality of packet switching terminals 4 are connected to the terminal. With such a configuration, not only can the circuit switching terminals 5 and 20 communicate via the circuit switching network 1, but also the packet switching terminal 4 and the circuit switching terminal 20 can communicate with each other via the circuit switching network 1.
It becomes possible to communicate with

Furthermore, as local communication, communication between the packet switching terminals 4 and communication between the packet switching terminals 4 and the circuit switching terminals 5 is also possible via the communication control device 3 without going through the circuit switching network 1. Become.

FIG. 2 is an internal configuration diagram of the communication control device in FIG. 1.

In FIG. 2, 6 is a C that controls the entire communication control device 3.
PU board; 7 is a buffer memory that temporarily stores transmitted and received data; 8 is a communication control board that is connected to the circuit switching terminal device 2 and stores firmware for the circuit switching protocol; 9 is a circuit switching terminal 5 or a packet switching terminal; 4
A plurality of communication control boards are connected to each other and store firmware for line switching and packet switching protocols for the lower three layers, respectively.

In this communication control device 3, communication between the line switching terminals 5 connected to the communication control board 9 or between the line switching terminals 5 and the line switching terminals 20 via the line switching network 1 is carried out by the CPU. Since speed conversion is performed by the operation of the board 6 and memory 7, communication between terminals with different line speeds is also possible. In addition, in communication between the line switching terminal 5 and the packet switching terminal 4 connected to the communication control board 9, the CPU board 6, memory 7, and communication control board 9 operate to control the line switching protocol and the packet switching protocol. This conversion enables communication between the circuit switching terminal and the packet switching terminal. Further, this communication control device 3 serves as hardware for the line switching terminal 5 and the packet switching terminal 4 as a line terminating device for line switching or packet switching.

FIG. 3 is a block diagram of the communication control board in FIG. 2.

In FIG. 3, 11 is an internal CPU'U, 12 is a memory including a RAM as a data buffer, a ROM that stores a line switching protocol and a packet switching protocol, 13 is a bus arbiter that manages the local bus 16, and 1
4 is a communication control LSI, 15 is a line termination device 2. This is a driver/receiver that performs transmission and reception with the packet switching terminal 4 or line switching terminal 5. Note that 10 is a system bus within the communication control device 3 shown in FIG. 2, and 16 is a local bus within the communication control board.

Arbitration between the communication control board 8 or 9 and the system bus 10 is performed by a bus arbiter 13.

When a communication control board is used as the communication control board 8 for an interface with the line exchange side, the ROM 12
Stores firmware such as protocols such as DTE for circuit switching. When receiving data from the line switching terminal 2o, the serial data binarized by the driver/receiver section 15 is sent to the communication control LS I.
14, is parallel-converted by the communication control LS 114, is transferred to the RAM unit 12 via the local bus 16, and is taken in there, so that line switching protocols such as header processing are performed.

In the case of transmission to the circuit switching terminal 20, it is completely the opposite, and the circuit switching protocol of the ROM section 12 allows the RA
The parallel data transferred from the M unit to the communication control LS 114 is converted into serial data, and then sent to the destination terminal by the driver/receiver unit 15.

Next, when the communication control board 9 is connected to a user's local terminal, the data flow is the same as that of a line switching interface. However, the firmware installed in the ROM section 12 is
There are two types of protocols: a circuit switching protocol as a CE and a packet switching protocol as a DCE for the packet switching terminal 4. For the circuit switching terminal 5 and the packet switching terminal 4, there is a hardware It becomes wear. For example, circuit connections are made such that the data transmitted from the packet switching terminal 4 becomes received data at the communication control board 9, and the data transmitted from the communication control board 9 becomes received data from the packet switching terminal 4. Also,
The driver/receiver 15 is designed to generate a clock for transmission and reception. This element clock is 2400 BPS to 4.5 BPS depending on the processing capacity of the terminal device 4.5.
The speed can be varied within a range of 8KBPS.

The entire communication control device 3 in FIG.
Under the control of IIJ, data transfer from communication control board 8 to communication control board 9 or from communication control board 9 to communication control board 8 is always performed via memory 7, not directly via system bus 10. As a result, even if the line switching terminal 5 is a terminal that can only communicate at a low speed, it is possible to store data in the memory 7 and then transmit it at a high speed using the communication control board 8. The same is true for reception. Also,
The firmware stored in the communication control boards 8 and 9 controls the lower layer of the frame of the packet switching terminal 4.
It is possible to convert it into a circuit switching protocol and transmit it to the circuit switching terminal 20.

The same is true for reception.

FIG. 4 is an operational flowchart when locally transmitting packets from the packet switching terminal 4 to the line switching terminal 5 in FIG.

When data is transmitted from the packet exchange terminal 4 to the communication control board 9, one communication control board 9 receives the data (step 41). Next, the received data from the first communication control board 9 is transferred to the memory 7 (step 42). CPU board 6
determines to which circuit switching terminal the data in memory 7 should be sent (step 43). Next, after format conversion of the data is performed on the CPU board 6, the data is stored again in the memory 7 (step 44). The data stored in the memory 7 is transferred to the communication control board 9 connected to the corresponding circuit switching terminal 5 (step 45). The communication control board 9 transmits data to the circuit switching terminal 5 according to the protocol of the circuit switching network (step 46).

Through this series of operations, data can be transmitted from the packet switching terminal 4 to the line switching terminal 5.

FIG. 5 is an operational flowchart when communication is performed locally between the circuit switching terminals 5 in FIG. 1.

Data is transmitted from the line switching terminal 5 to the communication control board 9 (step 51). In this case, the communication control board 9 has a protocol as a circuit switching network. next,
Transfer the received data of the communication control board 9 to the memory 7 (
Step 62). At this time, the CPU board 6 writes into the memory 7 information regarding which line switching terminal within the local area the transmission is to be made to. Further, the CPU board 6 checks information on which terminal the data is to be sent to, and transfers the data to the corresponding board 9 (step 53). The communication control board 9, acting as the network side of the circuit switching network, transmits data to the circuit switching terminal 5 (step 54).

FIG. 6 is an operation flowchart 1- during communication between the circuit switching terminals 5 connected to the communication control device 3 at a remote location, and FIG. 8 shows the communication system applied to FIG. 6. It is a block diagram.

As shown in FIG. 8, communication control devices 3 capable of communicating with each other are connected to remote locations via a circuit switching network 1, and one or more circuit switching terminals 5 are connected to these communication control devices 3 locally. and a packet switching terminal 4 are connected. In FIG. 6, from the line switching terminal 5 to the communication control device 3
．． Terminal device 2, circuit switching network 1. An operational flowchart is shown for transmitting data to the line switching terminal 5a via the termination device 2 and the communication control device 3a.

First, data is transmitted from the line switching terminal 5 to the communication control board 9 of the communication control device 3 (step 61). In this case, the board 9 has a protocol for the network side of a single circuit switched network. Next, data is transferred from the board 9 to the memory 7. At this time, the board 9 also writes the address information of the other party into the memory 7 (step 62). Next, data is transferred from the memory 7 to the board 8 (step 63). Data is transferred from the board 8 to the network termination device 2 (step 64). In this case, the board 8 has a protocol as a terminal. Next, from the remote network terminal device 2 to the board 8 of the communication control device 3a via exchange #11,
Data is transmitted (step 65). In this case, the board 8 has a protocol as a terminal. Data is transferred from the board 8 to the memory 7. At this time, the board 8 also writes the address information of the other party into the memory 7 (step 66). The CPU board 6 transfers data to the corresponding board 9 according to this address information (step 6
7). Next, data is transmitted from the board 9 to the line switching terminal 5a (step 68). In this case, board 9 is
It has a protocol as a network.

Of course, in the case of communication between circuit switched terminals, speed conversion is performed. This is achieved by converting the speed of the clock sent from the driver 15 in the board 9 to the terminal. Specifically, the communication control LS11 shown in FIG.
4 has a function of sending out a clock at an arbitrary speed, and this is sent to the terminal by the driver 15.

In addition, as another embodiment, in the case of communication not between terminals connected to the communication control devices 73 and 3a, but from a general circuit switching terminal to a circuit switching terminal connected to the communication control device 3, Figure 6 is applicable. In this case, the process starts from step 65. That is, data is transmitted from the general line switching terminal to the communication control board 8 via the network termination device 2 (step 65). Next, board 8
The data is transferred from the memory 7 to the memory 7. The board 8 also writes the address information of the other party to the memory 7 (step 66).
. The CPU board 6 transfers data to the corresponding communication control board 9 according to the address information (step 67).
Send data from board 9 to line switching terminal 5a (
Step 68).

FIG. 7 is an operational flowchart in FIG. 8 during communication from the circuit switching terminal 5 to the packet switching terminal 4a between remote locations.

Data is transmitted from the line switching terminal 5 to the board 9 of the communication control device 3 (step 71). Here, the board,
It has a protocol for the network side of a circuit-switched network. Next, data is transferred from the board 9 to the memory 7. At this time, the board 9 also writes the address information of the other party to the memory 7 (
Step 72).

Next, the CPU board 6 converts the line-switched format into the packet-switched format and stores it in the memory 7 again (step 72-2).

Next, data is transferred from the memory 7 to the board 8 (step 73). Next, from the board 8 to the network termination device 2,
Send the data (step 74).

In this case, the board 8 has a protocol as a terminal. Next, the data that has passed through the network reaches the network termination device 2,
From the terminal device 2 to the board 8 of the communication control device 3a,
Data is transmitted (step 75). Data is transferred from board 8 to memory 7. At this time, the board 8 also writes the address information of the other party in the memory 7 (step 76
). The CPU board 6 performs protocol conversion of the lower three layers based on the address information and data transfer to the corresponding board 9 (step 77). Data is transferred from the board 9 to the packet exchange terminal 4a (step 78).

At this time, the board 9 has a protocol as a network.

FIG. 9 is a diagram showing data format conversion between a circuit switching terminal and a packet switching terminal according to the present invention.

One frame of packet data is shown at the top, and one frame of line data is shown at the bottom. Both include a flag sequence F, a 1-byte address field A, a 1-byte control field C,
A level 3 header of 6 bytes etc., a data part of 256 bytes etc. including a level 4 or higher header part, a 2 byte frame check sequence FC5, and a flag sequence F
The flag sequence F is composed of .

The address field A, the control field, and up to the level 3 header are called the lower three layers.

Correlating the data format with the protocol structure of the switching network, the physical and electrical connection circuits and their operations are at the lowest level 1, which determines the electrical and physical conditions. The field C, Fe2°F is the frame level (level 2) that defines the procedure for controlling the transmission of information between terminals (data link control) and the procedure for recovering from error detection, and is the 6-byte level field shown in Figure 9. Level 4 or higher is the packet or line level (level 3) that determines the destination of the packet or line, and the header section within the 256-byte data section is level 4 or higher.

Note that there are also control frames in which no data exists.

In this way, in this embodiment, communication between a circuit switching terminal and a packet switching terminal at a remote location, and communication between a circuit switching terminal and a packet switching terminal at a local location are as follows.
Both are possible. In addition, for communication between circuit switching terminals in remote locations and between circuit switching terminals locally, circuit switching terminals that can handle high-speed lines (e.g., 48KBPS) and low-speed lines (e.g., 96008PS) are used.
), mutual communication becomes possible by performing speed conversion with circuit-switched terminals that can only be connected to

Furthermore, simply by installing the communication control device of this embodiment, it is possible to communicate with both circuit-switched terminals and packet-switched terminals. Just by signing an exchange contract, all communications can be carried out freely. In addition, the storage function in the communication control device of this embodiment allows repeat communication to the same local terminal, so there is no need to pay line usage fees.
Circular communication is possible.

Effects As explained above, according to the present invention, communication is possible between a circuit switching terminal and a packet switching terminal. It is extremely useful for users because it also enables communication with line-switched terminals.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a communication system showing an embodiment of the present invention, FIG. 2 is an internal configuration diagram of the communication control device in FIG. 1,
Figure 3 is an internal configuration diagram of the communication control board in Figure 2;
Figure 4 is an operation flowchart in Figure 1 when locally transmitting packets from a packet switching terminal to a circuit switching terminal, and Figure 5 is in Figure 1 when communicating between local circuit switching terminals. Figure 6 is an operation flowchart for communication between circuit switching terminals connected to a communication control device at a remote location, and Figure 7 is a flowchart for transmitting data from a remote circuit switching terminal to a packet switching terminal. An operation flowchart for communication; FIG. 8 is a block diagram of the communication system applied to FIGS. 6 and 7;
FIG. 9 is an explanatory diagram showing an example of data conversion. 1: circuit switching network, 2: terminal device, 3, 3a: communication control device, 4, 4a: packet switching terminal, 5° 5a: circuit switching terminal, 20 d general circuit switching terminal. Figure 1 Figure 2 Figure 4 Figure 5

Claims (6)

[Claims] (1) In a communication control device connected to a line termination device of a circuit exchange, a first communication control device connected to at least one or more local circuit switching terminals and packet switching terminals and connected to the line termination device. a second communication control means connected to the local circuit switching terminal and the packet switching terminal; a data buffer interposed between the first and second communication control means; CPU that controls the first and second communication control means
The first communication control means has a line switching protocol, the second communication control means has a line switching protocol or a packet switching protocol, and the CPU and data buffer A communication control device characterized by performing protocol conversion of lower three layers or data speed conversion. (2) When the second communication control means locally communicates between the circuit switching terminal and the packet switching terminal, the second communication control means stores the received data in a data buffer, and converts the protocol using the other second communication control means. The communication control device according to claim 1, characterized in that the communication control device performs the following. (3) The second communication control means stores the received data in the data buffer and performs speed conversion by the other second communication control means when performing communication between the line-switched terminals locally. A communication control device according to claim 1, characterized in that: (4) When the second communication control means performs communication between circuit switching terminals connected to a communication control device at a remote location, the second communication control means stores received data in a data buffer and also transmits address information of the other party. After writing the data into the data buffer, it is transferred to the first communication control means, and sent from the first communication control means to the circuit switching network, and the data is transferred to the first communication control device of the other party.
2. The communication control device according to claim 1, wherein data is transmitted to the other party's line switching terminal via the communication control means, the data buffer, and the second communication control means. (5) When communicating between a circuit switching terminal and a packet switching terminal connected to a remote communication control device, the second communication control means controls the first and second communication control devices of both communication control devices. Claim 1, characterized in that data is transferred via a communication control means and a data buffer, and format conversion of protocols up to the lower three layers is performed based on destination address information written in the data buffer. The communication control device described. (6) The second communication control means communicates with the first communication control means and the data buffer when communicating between a line switching terminal connected to the communication control means and a general line switching terminal. 2. The communication control device according to claim 1, wherein data is transferred via a communication control device.