JP3008720B2 - ISDN signal switching equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exchange for relaying an ISDN signal used for an interface between a central office or a private branch exchange having an ISDN communication function and a terminal equipment having an ISDN termination function. Related to the device.

[0002]

2. Description of the Related Art Conventionally, this type of ISDN signal relay switching apparatus has a function of transparently relaying ISDN signals, and allocates lines and resources in a fixed manner for each connection between a terminal and an exchange. Therefore, the ISDN signal can be relayed.

[0003]

However, in the conventional ISDN signal transit switching apparatus, the line and the resource are used fixedly for each connection between the terminal and the exchange.
There has been a problem that the number of connectable terminals is limited by the number of lines and the number of resources of the ISDN signal transit switching apparatus, which are set between the ISDN signal transit switching apparatus and the exchange.

[0004] The present invention solves such a conventional problem. By allocating lines and resources only to calls in communication, the efficiency of lines and resources is improved, and exchanges and ISDN signal relays are made. It is an object of the present invention to provide an excellent ISDN signal transit / exchange device that can connect a terminal without being limited by the number of lines and the number of resources of the ISDN signal transit / exchange device between stations.

[0005]

According to the present invention, in order to achieve the above object, a signal monitoring function is provided in a signal processing unit,
It is possible to have a signal transmission / reception management function for acquiring and releasing resources.

Further, as a countermeasure in the event of a failure, I
It has a function of terminating and managing layer 1 of the SDN protocol and a function of managing signals by providing a signal management function in layer 2.

[0007]

Therefore, according to the present invention, a resource and a line are separated by enabling the resource to be acquired for each communication request, instead of being fixedly allocated between the exchange (PBX) and the terminal. Has the effect that resources can be used efficiently.

Further, according to the present invention, by setting resources to the line common area, the number of lines with the exchange (PBX) can be minimized. However, it has the effect that it can be installed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a network using an ISDN signal transit switching apparatus according to the present invention.

In FIG. 1, reference numeral 1 denotes an ISDN according to the present invention.
Reference numeral 2 denotes a terminal connected to the apparatus 1 and reference numeral 3 denotes an exchange (PBX) connected to the relay apparatus 1.

As shown in FIG. 1, a relay device 1
And the terminal 2, so that the exchange 3 and the terminal 2 can be connected.

FIG. 2 shows the protocol hierarchy and the handling of the protocol in the configuration of FIG. As shown in FIG. 2, the physical layer, Layer 1, terminates between the terminal 2 and the relay device 1 and between the exchange 3 and the relay device 1, but is the data link layer, Layer 2, and the network layer. The layer 1 is transparent for the layer 3 and is terminated between the terminal 2 and the exchange 3 to reduce the design amount at the protocol level.

FIG. 3 is a sequence diagram showing how the relay apparatus 1 uses resources, which are areas for transferring communication data such as voice and data.

In FIG. 3, when receiving the call setup message 11 from the terminal 2, the relay device 1 acquires resources. Thereafter, a call setting message 12 is sent to the exchange 3. If the exchange 3 can accept the call, the relay device 1 receives the response 13 from the exchange 3. Next, the relay device 1 allocates the acquired resources to the corresponding communication, and sends a response 14 to the terminal 2.

At this stage, between the terminal 2 and the exchange 3,
The communication path 15 is established via the resource, that is, through the relay device 1, and shifts to Layer 2 and Layer 3.
Here, voice and data are transmitted and received between the terminal 2 and the exchange 3.

When the communication is completed, a disconnection message (not shown) is exchanged. Thereafter, the relay device 1 receives the release message 16 from the exchange 3 and prepares for release of the resources. Next, the relay device 1 sends a release message 17 to the terminal 2, and upon receiving a release completion message 18 from the terminal 2, releases the resources and sends a release completion message 19 to the exchange 3.

As described above, the resource of the relay device 1 is monitored by monitoring the signal of the layer 3 to acquire the resource at the start of communication and to release the resource at the end of communication. The configuration is such that it is only during communication, and at other times, the same resource can be used in another terminal.

The operation of the present apparatus in the event of a layer 1 failure is as follows. When a failure occurs, the communication is temporarily stopped to enter a non-communication state, so that the resource is released, and the resource is not held during the non-communication.

FIG. 4A shows the state transition and processing of layer 2 fault monitoring. Since the relay apparatus does not terminate Layer 2, it cannot perform any processing on the signal of Layer 2.

For this reason, the communication state at both ends is predicted by monitoring the signal of the layer 2, and when it is determined that the communication is disconnected due to the layer 2 failure, the resource is released.

It should be noted that a failure of layer 3 is monitored by monitoring a communication protocol and having a timer according to the protocol, so that termination of the protocol is not performed, but a state transition function according to the protocol is provided. This enables fault management.

In FIG. 4A, T1 is a UA reception waiting timer, and T2 is an S frame or e-frame waiting timer. Also, in FIG. 4B, A is a symbol for signal reception, B is a symbol for event reception in the system, and C is a symbol for event reception in the system.

[0024]

According to the present invention, as is apparent from the above embodiment, resources are managed each time a communication is generated or terminated, and resources are not fixedly allocated. The resources can be shared by these terminals, and the number of connected terminals can be set up without being influenced by the number of resources or the number of lines.

Further, according to the present invention, a fault is managed for each layer, so that even when a fault occurs, there is no need for a human to manage the resource, and the resource can be managed automatically.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a system using an ISDN signal transit switching apparatus according to the present invention;

FIG. 2 is a diagram showing a protocol configuration of the present invention.

FIG. 3 is a sequence diagram showing a method of using resources of the relay device.

FIG. 4 is a state transition diagram of layer 2 in the relay device.

[Explanation of symbols]

 1 ISDN signal transit switching equipment 2 terminal 3 exchange (PBX)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04L 12/02 H04M 11/00 303 H04Q 3/42 104

Claims (1)

(57) [Claims] 1. An ISDN provided between a terminal and an exchange in a layer 1 on a communication path between the terminal and the exchange.
Relaying a signal, transmitting communication data between the terminal and the exchange at Layer 2 and Layer 3, acquiring a resource for transferring the communication data when receiving a call setup message from the terminal or the exchange, and releasing a release message ISDN signal relay exchange that releases the resources when
Switching device, and when a failure occurs in layer 1,
Stop communication temporarily to disable communication and release resources
And do not hold resources during non-communication
However, when a failure occurs in layer 2, the layer 2
The communication status at both ends by monitoring the
If it is determined that communication has been disconnected due to this failure
Releases resources and reports that Layer 3 has failed
Monitor the communication protocol,
Fault monitoring by having a timer
State transition function according to protocol without terminating
IS characterized by having trouble management by having
DN signal transit switching equipment.