JPS6336176B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for implementing protocol conversion in a circuit switch.

As is well known, there are two types of data exchange methods: circuit switching and packet switching.
Both have their own advantages and disadvantages, and are said to have different application areas. For example, the packet switching method is economical for exchanging low-speed data that occurs in bursts, and because it performs store-and-forward, it is easy to implement communication processing functions such as speed conversion and code conversion. I have it. On the other hand, circuit switching is suitable for exchanging large amounts of data at high speeds that occur continuously, provides a transparent communication path between terminals, and is generally much simpler to control than packet switching. Also, for exchanges that integrate data and voice, both packet switching and circuit switching systems are considered, but if the emphasis is placed on voice, circuit switching systems are considered to be more advantageous for such exchanges. . This is because voice can be regarded as a large amount of data that is generated continuously at high speed.

However, the drawback of the line switching system is that it provides a transparent communication path between terminals, so it is difficult to incorporate communication processing functions such as speed conversion and code conversion. This is true for line switching equipment, regardless of whether it is a data switching equipment or an integrated voice/data switching equipment.

For example, in FIG. 1A, the line exchange 10 is
Information processing between terminals, such as terminals 11 and 12, terminal 13, and terminals that agree on speed, codes, transmission control procedures, or higher-level protocols (these are collectively referred to as protocols in a broad sense) If the devices (computers) 14 are connected via a transparent communication path via the switch network 15, communication between both terminals of each set becomes possible. (In Fig. 1, the difference in protocols is represented by one line and two lines.) However, even if the terminal 11 and the information processing device 14 and the terminal 13 and the terminal 12 are connected by a transparent connection path, Communication is not possible because the protocols of each terminal are different. Therefore, even if each terminal is connected to many terminals via an exchange, it will only be able to actually communicate with terminals that use the same protocol as its own terminal, and services will be limited accordingly. and its usefulness decreases. Note that information processing devices such as computers also appear to be equivalent to terminals when viewed from an exchange, so they will be collectively referred to as terminals. In addition, the circuit switching method includes a multiple switching method that allocates a communication path with a band corresponding to the speed when the signal speeds of terminals differ, and a method that unifies the speed of each signal to the fastest signal speed by multi-point sampling etc.
There is a unit exchange method that allocates communication paths having the same bandwidth. In the case of multiple switching systems, it is usually impossible to even establish a transparent communication path if the speeds of terminals are different. Therefore, the following explanation will mainly assume the unit exchange method.

In addition, in FIG. 1A, 16 is the line exchange 10.
17, 18, 19, and 20 are interface circuits for detecting outgoing calls, incoming calls, recovery, etc. from the terminal, and for receiving destination numbers.

Now, if you want to somehow connect terminals with different protocols as mentioned above, the first
As shown in Figure A, there is a
The method used was to insert a protocol conversion circuit. This protocol conversion circuit realizes mutual conversion between specific protocols, or selects conversion between a plurality of protocols by switching a switch. According to this method, by knowing the protocol type of the destination terminal, it is possible to realize interconnection between terminals with different protocols by switching a switch or selecting a protocol conversion circuit. be. However, this method basically only converts a terminal with one protocol into a terminal with another protocol, and allows free connection to other terminals with various protocols. isn't it. Even if a protocol conversion function is selected depending on the destination terminal, there must be a human intervention and sufficient information regarding the protocol of the destination terminal. In addition, if the other party's terminal also has a function to select protocol conversion, the protocol of the other party's terminal may be
Since it may change from time to time, some sort of meeting is required, resulting in a complicated and rather inconvenient system.

In addition, in order to expand the range of terminals that can communicate, it is necessary to expand the selection range of the protocol conversion function, but since the protocol conversion circuit 21 is installed to support terminals, there is no sharing effect. Expanding functionality will immediately lead to higher costs.

On the other hand, as shown in FIG. 1C, the protocol conversion circuits 22 and 23 are installed as trunks within an exchange and shared by many terminals. In other words, in Figure 1C, line exchange 1
0's control unit 16 holds the protocol attributes (including speed, code, etc.) of each terminal connected to the exchange as data, and when the terminal 11 makes a call, the calling terminal 11 and the called terminal 14 The protocol attribute data of the two terminals is extracted and compared, and the possibility of communication between the two terminals is determined. If it is determined that communication is not possible, the control unit 16 selects a protocol conversion trunk 22 that mutually converts the protocols of both terminals, and connects the calling terminal 11 and the called terminal 14 to each protocol conversion trunk 22. After that, communication between the two terminals will begin. The protocol conversion trunks 22 and 23 are provided for each combination according to the types of protocols of the terminals accommodated in the circuit exchange 10.

Alternatively, if the protocol conversion trunk is a general-purpose conversion trunk that performs mutual conversion between arbitrary protocols of terminals accommodated in the circuit exchange 10, the control unit 16 determines that communication is not possible as a result of attribute matching, and then The calling terminal 11 and the called terminal 14 are connected to the protocol conversion trunk, and the protocol attributes of both terminals are notified to the protocol conversion trunk by means of communication provided between the calling terminal 11 and the called terminal 14. After that, communication between the two terminals will begin.

With this method, the user who uses the terminal does not need to be aware of the protocol attributes of the other terminal with which he or she wishes to communicate, and since the protocol conversion circuit is shared by many terminals, it is advantageous in terms of cost. The functions to be performed by the control section of the exchange are increased, leading to an increase in the scale and complexity of the control section and the required processing power. Furthermore, various types of terminals will continue to be developed in the future, and new ones with new protocol attributes are expected to appear, so various changes will be necessary in the retention of protocol attributes and the function for comparing them.
However, changes to large-scale and complex hardware and software are extremely difficult in practice, resulting in a significant reduction in flexibility.

The present invention overcomes such drawbacks in the prior art, and uses a circuit switching method that is easy to control and suitable for high-speed, large-volume data exchange by installing a control circuit for each terminal in addition to a protocol conversion trunk. The objective is to obtain a protocol conversion method that economically realizes a communication processing function or a protocol conversion function while taking advantage of the advantages, and allows free connection between terminals using different protocols.

That is, according to the present invention, a protocol conversion method in a circuit exchange is provided in which a control circuit is provided in the input/output section of the circuit exchange corresponding to each terminal, and a communication path established between the terminals is established prior to the start of communication between the terminals. The possibility of communication is determined by transmitting and receiving information regarding the protocol of each terminal between the control circuits corresponding to the respective terminals, and if communication is not possible due to the difference in the protocols, the control circuit controls:
The necessary protocol conversion can be achieved by opening only the communication path or both the communication path and the terminal and setting up a new communication path from the calling terminal to the receiving terminal via the protocol conversion trunk. A characteristic protocol conversion method is obtained.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 2 is an explanatory diagram showing an embodiment of the present invention.
In FIG. 2A, the line exchange 10 is connected to the terminal 11
When the user makes a call, the controller 16 receives the calling information and the number of the other party through the interface circuit 30.
Under the control of
to notify you of an incoming call. Interface circuit 30, 3
1 is the interface circuit 17, 1 in FIG.
8, 19, and 20, but have control circuits 32 and 33, respectively.
And as mentioned above, switch network 15
When a communication path is set in the communication path, the control circuits 32 and 33 use this communication path to send and receive information regarding the protocols of each terminal before calling the other party's terminal 14, so that the protocols of both devices match. That is, whether direct communication is possible between the terminals. It is assumed that the control circuits 32 and 33 retain information regarding the protocols of the corresponding terminals by registering them in advance or the like. As mentioned above, it is assumed that the line exchange 10 mainly uses the unit switching method.
Even if it uses a multiple exchange method, in some way,
For example, when two terminals have different speeds, a communication path is set according to the higher speed terminal, and transmission and reception between the control circuits 32 and 33 is performed using only the band corresponding to the lower speed terminal. The present invention can be similarly applied by using the method described in .

As a result of exchanging information regarding the protocols between the control circuits 32 and 33 as described above, if it is determined that the protocols match and communication is possible, the control circuit 33 calls the terminal 14 through the interface circuit 31. , waits for the response, and then shifts to direct communication via the path of terminal 11 - interface circuit 30 - switch network 15 - interface circuit 31 - terminal 14.

On the other hand, if the protocols do not match and it is determined that direct communication between the terminals is impossible, the control circuit 3
2 or 33 sends a signal to the control unit 16 of the line exchange indicating that the communication has ended,
Open the communication path set between both terminals. However, at this time, the originating terminal 11 is left in a state of waiting for a response from the other party's terminal.

After that, the control circuit 32 sends a signal to the control unit 16 that makes it appear as if the terminal 11 has made a call again, and when the signal is accepted, it sends the number assigned to the protocol conversion trunk 34 as the destination number, and the terminal 11 to protocol conversion trunk 3
Switch network 15 for communication route leading to 4.
Set inside. (Figure 2A) Through this communication path, the control circuit 32 connects the protocol conversion trunk 3
4, the other party's number indicating the terminal 14 is notified. The protocol conversion trunk 34 has two terminals, and the other terminal is used to send an outgoing signal to the control unit 16, and after it is accepted,
A communication path from the protocol conversion trunk to the terminal 14 is set by sending out the other party's number indicating the terminal 14. (Fig. 2 c) The control circuit 33 then
The terminal 14 is called through the interface circuit 31. When the terminal 14 responds, the control circuit 33 notifies the protocol conversion circuit 34 and the control circuit 32 of the response via the communication path set, and then the terminal 11 - interface circuit 30 - switch.
Network 15-Protocol Conversion Trunk 34
The communication between the terminals is shifted to the path: - switch network 15 - interface circuit 31 - terminal 14. (FIG. 2D) Until this time, the calling terminal 11 waits for a response from the other party, but from then on, it becomes possible to communicate through the protocol conversion trunk without being aware of the difference in protocol with the other terminal.

In addition, in order to avoid a long wait time for the other party's response, when it is determined that communication is impossible due to the transmission and reception of protocol information between the control circuits 32 and 33, the communication path set between the two terminals is In addition to this, it is also possible to consider ways to open up terminals as well. In this case, under the control of the control circuits 32 and 33,
After setting a communication route via the protocol conversion trunk 34, procedures such as calling the calling terminal and the receiving terminal are performed.

As the protocol conversion trunk, several types of trunks are prepared depending on the conversion contents, and the control circuits 32 and 33 compare the protocols to determine the conversion trunk to be selected and send out that number. After preparing a general-purpose conversion trunk and uniformly connecting to the general-purpose conversion trunk, the control circuit 32 or 33 notifies the protocol information and sets the necessary protocol conversion according to the content. There are several possible methods. An intermediate method between the two is also possible. Regardless of whether you use individual conversion trunks or general-purpose conversion trunks, it is likely that multiple equivalent trunks will be installed, but by assigning representative numbers to them, you can easily select the desired vacant conversion trunk. can be connected.

As can be seen from the above, according to the present invention, each terminal can automatically undergo protocol conversion without being aware of the protocol of the other terminal, and can access various terminals with different protocols. . Therefore, one terminal can be connected to various devices such as computers, word processors, databases, etc. and receive their services, making it extremely useful.

Furthermore, the present invention is based on a circuit switching method, which is much easier to control than a packet switching method, and is advantageous for exchanging large amounts of data (voice, etc.) that occur continuously at high speed. While retaining the advantages of the circuit switching method,
The results are considered to be significant, since the lack of communication processing function or protocol conversion function, which has been considered a weakness of conventional line switching systems, can be easily overcome.

In the present invention, there is almost no need to make any changes to the basic architecture of the line exchange, such as detecting a call, receiving the other party's number, setting a communication route, calling the other party's terminal, and detecting the completion of communication.
Therefore, there is almost no need to change the hardware or software of the control section. In other words, it is extremely easy to implement. This is the result of clearly separating the communication path setting function and communication processing function into the circuit switching control section and the protocol conversion trunk. can be flexible and concise.

Furthermore, the protocol conversion trunk is economically advantageous because it is shared by many terminals, and it is possible to provide it with higher functionality. Furthermore, by adding conversion trunks and expanding functions, it is possible to easily increase traffic capacity and expand the scope of protocol conversion. In addition, the conversion trunk is structured like a single module, so it is possible to easily incorporate the results of technological advances such as LSI technology.

In the previous explanation, we described a method of transmitting and receiving protocol information between the control circuits 32 and 33 and determining that the communication has ended when it is determined that communication is impossible. If a private telephone exchange has functions such as a hooking function or a line hold function, it is also possible to use these functions to set up a communication path from the calling terminal to the called terminal via the protocol conversion trunk. .

In addition, the communication path from the originating terminal to the terminating terminal via the protocol conversion trunk should be set up from the originating side or from the terminating side, how protocol information should be sent and received, and the possibility of communication. Various combinations can be considered as to which control circuit should be used to make the determination, but the present invention is not limited to these specific combinations.

Furthermore, although the control circuits 32 and 33 are provided for each terminal, if processing capacity is available, a configuration in which one control circuit is in charge of a plurality of terminals is also possible.

As described in the embodiments above, according to the present invention, by installing a control circuit for each terminal together with a trunk for protocol conversion, communication processing function or protocol conversion can be performed economically while taking advantage of the circuit switching system. The effect is significant, as it enables the implementation of various functions and allows free connection between terminals using different protocols.

[Brief explanation of the drawing]

FIGS. 1A, 1C, and 1C are explanatory diagrams showing a conventional circuit switching system and a protocol conversion system in the circuit switching system, and FIGS. In the figure, 10 is a line exchange, 11, 12,
13 and 14 are terminals, 15 is a switch network, 16 is a control unit, 17, 18, 19, 20, 3
0 and 31 are interface circuits, 32 and 33 are control circuits, and 22, 23, and 34 are protocol conversion trunks.

Claims (1)

[Claims] 1 A protocol conversion method in a line exchange, in which a control circuit is provided in the input/output section of the line exchange for each terminal, and before the start of communication between the terminals, each terminal is The possibility of communication is determined by transmitting and receiving information regarding the protocol of each terminal between corresponding control circuits, and if communication is not possible due to differences in protocols, only the communication path is controlled by the control circuit. Alternatively, a protocol conversion characterized in that the necessary protocol conversion is realized by opening both the communication path and the terminal and setting a new communication path from the calling terminal to the receiving terminal via the protocol conversion trunk. method.