JPH09289533A - Shifting system from point to point communication to point to multi-point communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit a pre-existed device to execute a low-order protocol terminating function by permitting an additional local device to provide a command reception/through circuit and a command judgement processing function and not to be concerned in a low-order protocol processing. SOLUTION: When a center device 12 and a local device A14 already execute point to point communication, the local device B15 having a new external interface 18 is added inside the same local device 13. And the command reception/ through circuit and a command response judgement processing circuit are mounted as the inner circuit of the local device B15. The local device 14 realizes point to multi-point communication by a communication protocol as in a conventional manner without circuit/function change. That is, the newly added local device is provided with the command reception/through circuit, etc., and is made not to be concerned in the low-order protocol processing.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a communication system,
In particular, it relates to point-to-multipoint communication system technology.

[0002]

2. Description of the Related Art Conventionally, a center device and a local device A are LAP-B (Link Acccess Procedure-Balanced;
When performing point-to-point communication such as balanced link access procedure), a local device B is added to the same local station to add an external interface device, and the center device and the local devices A and B are added. When communicating with each other, it is necessary to adopt one of the following methods.

A new line is added for communication between the center device and the local device B.

The local device B is provided with a protocol termination function between center devices and between local devices A.

LAP-D (Link Acccess Procedure)
on the D-channel; totally different protocol such as D channel link access procedure and point-to-multipoint (broadcast) link is adopted.

[0006]

In the above-mentioned conventional communication system, the above-mentioned system has a problem that a new line needs to be added, and the line addition is costly.

Further, in the case of the above-mentioned method, it is necessary that the local device B has a protocol termination function between the center devices and between the local devices A, and unnecessary processing (protocol that does not need to terminate) is performed. A delay may occur due to local device B terminating).

Further, in the case of the method (1), a new system has to be developed, and the development scale and man-hour increase,
It has a problem of high cost.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a network in which point-to-point communication is already performed.
When adding a device with a new external interface in the same local station, while simplifying the circuit device configuration, reusing the existing device to achieve resource reuse, speeding up and improving transmission efficiency It is to provide a communication method that satisfies performance characteristics such as.

[0010]

In order to achieve the above object, the present invention provides a network in which a center device and a local device perform point-to-point communication,
This is a method for newly adding a local device having a different external interface in the same station as the local device (referred to as “existing local device”) and shifting to point-to-multipoint communication, which is newly added. The local device includes means for receiving a command and switching between a through state to the existing local device, and means for determining and processing the command, and the newly added local device responds to a lower layer response. At the time of switching to the existing local device side, at the time of application layer response, switching to the own device side, and in the network that performs point-to-multipoint communication, the existing local device performs the termination function of the lower protocol. From point-to-point communication to point-to-point communication. · To provide a multi-point migration method to the communication.

According to the method of the present invention, existing points
In order to shift the point-to-point communication to the point-to-multipoint communication, the newly added local device has the command receiving / through circuit and the command judgment processing function, and does not involve the processing of the lower protocol. Therefore, in the point-to-multipoint communication network, the existing device can be provided with the terminating function of the lower protocol as before.

[0012]

Embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, according to the embodiment of the present invention, when the center device 12 and the local device A 14 are already performing point-to-point communication, a new external device is provided in the same local station 13. A new local device B15 having an interface 18 is added,
As an internal circuit of the local device B15, command reception /
A through circuit and a command / response determination processing circuit are mounted, and the local device A14 is configured to realize point-to-multipoint communication by the conventional communication protocol without changing the circuit / function. .

FIG. 2 shows the internal circuit configuration of the local device B15 added to the local station 13. Referring to FIG. 2, the local device B15 is the center device 1
2, a reception buffer 23 and a transmission buffer 24 for communication with the local device A14, a reception buffer 21 and a transmission buffer 22 for communication with the local device A14, and a command from the center device to the local device A14. A pattern 27 to be passed through and a pattern 28 to be taken in,
A command / response determination circuit 26 that determines the command from the center device 12 that has been taken in, and a transmission signal switching selector circuit that switches the transmission signal to the center device (transmission signal switching between the local devices A and B) according to the determination result. 25 are provided.

Next, the operation of the embodiment of the present invention will be described in detail with reference to FIG.

First, the center device 12 establishes a protocol between the local devices (steps S1 and S2).
At this time, the local device B15 allows the protocol establishment signal from the center device 12 to pass through to the local device A14, and at the same time, takes in the protocol establishment signal to the command determination circuit 26.
Thus, the transmission signal switching selector circuit 25 is switched to the local device A14 side.

As a result, the protocol is established between the center device 12 and the local device A14.

Thereafter, the center device 12 periodically collects alarms by issuing an alarm request command to each local device.

From the center device 12 to the local device A14
When collecting alarms for (steps S3 to S
In 6), the center device 12 issues an alarm request command for the local device A14. At this time, the local device B15 causes the alarm request for the local device A14 from the center device 12 to pass through to the local device A14. At the same time, it is taken in and the command determination circuit 26 switches the transmission signal switching selector circuit 25 to the local device A 14 side until the sequence ends.

As a result, the center device 12 normally collects alarms from the local device A14.

When collecting the alarms of the local device B15 (steps S7 to S10), the center device 12 is used.
Issues an alarm request command for the local device B15. At this time, the local device B15 causes the alarm request for the local device B15 from the center device 12 to pass through to the local device A14, and at the same time, fetches the command internally. The determination circuit 26 switches the transmission signal switching selector circuit 25 as follows.

When the lower layer responds to the alarm request command, the local device A14 is switched to.

When the application layer responds to the alarm request command, the response determination circuit 26 confirms the establishment of the lower layer, and then the local device B
Switch to the 15 side.

As a result, when the center device 12 collects an alarm from the local device B15, the lower protocol layers are normally processed by the local device A14,
On the other hand, in the application protocol layer, by communicating with the newly added local device B15, the alarm is normally collected from the local device B15 without changing the function / configuration of the existing local device A14.

The center device 12 to the local device A
Due to a failure of the local device A14 at the time of establishing a protocol between 14 or when collecting an alarm from the local device B15,
If the lower protocol cannot be established, a predetermined time t
After waiting for the (lower layer establishment time timer), the local device B15 itself establishes the lower protocol layer and responds to the application layer (steps S11 to S1).
8).

[0026]

Next, an embodiment of the present invention will be described in detail with reference to FIG.

First, the center device 12 establishes the LAP-B protocol between the local devices (step S1,
S2), but at this time, the local device B15 sends the LAP-B protocol establishment signal (SABM;
Set Asynchronous Balanced Mode Extended, asynchronous extended balanced mode setting, frame for activating the logical link setting of multi-frame mode) to the local device A1
At the same time as passing through to No. 4, the command signal is fetched inside, and the command determination circuit 26 switches the transmission signal selector 25 to the local device A14 side.

As a result, the local device A14 becomes LAP-
B Protocol establishment response (UA; Unnumbered Acknowledgment)
ge; unnumbered confirmation), LAP-B
The protocol is established by the center device 12 to the local device A.
It is performed between 14th.

After that, the center device 12 periodically
Alarms are sequentially collected by issuing an alarm request command to each local device.

When collecting the alarms of the local device A14 (steps S3 to S6), the center device 12
Issues an alarm request command (one frame) for the local device A14. At this time, the local device B
Reference numeral 15 allows an alarm request for the local device A14 from the center device 12 to pass through to the local device A14, and at the same time, takes in the alarm request.
The transmission signal switching selector circuit 25 is switched to the local device A14 side until the sequence is completed.

As a result, the center device 12 normally collects alarms from the local device A14.

When collecting alarms from the local device B15 (steps S7 to S10), the central device 12
Is an alarm request command (1
Frame), but at this time, the local device B15
Causes an alarm request for the local device B from the center device 12 to be passed through to the local device A14 and at the same time taken in, and the command determination circuit 26 switches the transmission signal selector 25 as follows.

On the side of the local device A14 at the time of response to the lower layer (RR; Receive Reedy; indicating that frame reception is possible) in response to the alarm request command.

When the application layer responds to the alarm request command, the response determination circuit 25 confirms the establishment of the lower layer, and then the local device B
15 side.

As a result, when the center device 12 collects an alarm from the local device B15, the local device A14 keeps the lower protocol layer as it is.
By communicating with the newly added local device B15 in the application protocol layer, the alarm is normally collected from the local device B15 without changing the function / configuration of the local device A14.

The center device 12 to the local device A
If the lower protocol cannot be established due to a failure of the local device A14 at the time of establishing the LAP-B protocol between the four devices 14 or at the time of collecting the alarm from the local device B15, wait the time t (lower layer establishment time timer) and wait for the local device B15. Itself establishes the lower protocol layer and responds to the application layer (steps S11 to S1).
8).

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 shows a second embodiment of the present invention.
It is a figure showing an embodiment.

FIG. 4 shows a case where a plurality of local devices are installed in the same local station 44. By introducing the above-mentioned local device B as a local device to be sequentially added, point-to-multipoint communication is performed. Can be realized.

[0039]

As described above, according to the present invention,
There is an effect that the transition from the existing point-to-point communication to the point-to-multipoint communication can be easily realized without affecting the existing processing.

This is because, in the present invention, the newly added local device has a command receiving / through circuit and a command determination processing function, and does not participate in the processing of the lower protocol. This is because it is possible to allow existing equipment to perform the lower-layer protocol termination function as in the past in a point-to-multipoint communication network.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a circuit configuration of a local device B in the embodiment of the present invention.

FIG. 3 is a diagram for explaining the embodiment of the present invention and is a diagram showing an example of an information transfer sequence.

FIG. 4 is a diagram showing another embodiment of the present invention.

[Explanation of symbols]

 11 center station 12 center device 13 local station 14 local device A 15 local device B 16 communication line 17 external interface 4A 18 external interface 4B 21 receive buffer between local devices 22 send buffer between local devices 23 receive buffer between center devices 24 between center devices Transmission buffer 25 Transmission signal switching selector 26 Command / response determination circuit 27 Through pattern to local device A 28 Capture pattern to the inside 49 Local device X 50 Local device Y 51 External interface X 52 External interface Y

Claims (2)

[Claims] 1. In a network in which a center device and a local device perform point-to-point communication, a local device having a different external interface is newly added in the same station as the local device (referred to as "existing local device"). And a command for the newly added local device to switch between receiving a command and switching to the existing local device. And a means for performing a point-to-point operation, the newly added local device is switched to the existing local device side when a lower layer response is made, and is switched to the own device side when an application layer response is made.・ In the network that performs multipoint communication, Characterized in that to perform the protocol termination function, migration method from point-to-point communication to point-to-multipoint communications. 2. In a network in which a center device is connected to a first local device and a second local device and responds to a command from the center device, the center device is provided with the first and the first local devices in response to a request from an operator. 2 means for transmitting a command to which a destination is added to a local device, said first local device comprising means for terminating a lower protocol in response to a command from said center device regardless of the destination, said second local device The device includes a transmission / reception buffer between the center devices and the first local device, means for passing a command from the center device to the first local device, and means for capturing the command in the own device.
Further, it has a means for determining a command captured in its own device, a means for determining whether the command captured in its own device is addressed to its own device or to another local device, and Means for responding only to a device-addressed command by waiting for a response of a lower protocol from the first local device, a command from the center device, and / or the first device
And a means for switching a transmission signal to the center device in response to a response from a local device, and a transition method from point-to-point communication to point-to-multipoint communication.