JPH0221746A - Channel assignment method for line exchange - Google Patents

Abstract

PURPOSE:To reduce the time setting a call and to relieve the load of a center node equipment by allowing a local node equipment to acquire the right of use of plural line exchange channels from the center node equipment when a terminal equipment makes a call at first after the leading of the system. CONSTITUTION:The local node equipment LN acquires the right of use of plural line exchange channels from the center node equipment CN in advance. Thus, every time a call comes from the terminal equipment TE, it is not required for the local node equipment LN connecting to the caller terminal equipment TE to send an assignment request packet for the line exchange channel to the center node equipment CN. Thus, the time for setting a call is reduced and the load of the center node equipment is relieved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a circuit switching channel allocation method for performing circuit switching on a local area network (LAN).

BACKGROUND ART FIG. 2 shows a loop-type local area network, in which 1 is a center node (CN) that manages the entire network, and 2.3 is a terminal device (TE) 4 to 3, respectively. 9 and a sub-network (not shown) in this local area network. In this example, the local node device 2 accommodates the terminal devices 4 to 6, and the local node device 3
houses the terminal devices 7-9.

FIG. 3 shows the structure of frames transmitted on the loop-type transmission path of FIG.
H), a packet switching section, and a line switching section.

- The kerato exchange section is provided with each packet data, a delimiter identification code called DeIJ Mita that is provided at the beginning and end of this packet data, and a token that is provided at the beginning of the next area in which packet data can be written. When transmitting packet data, the token on the loop is identified and transmitted sequentially from the token part, the delimiter, the packet data, overwriting the delimiter, and finally the new Send the token.

The line switching section consists of time slots TS1 to TSn that can be assigned to each line switching channel.
A method of allocating a conventional circuit switched channel using the above token is shown.

In FIG. 4, for example, when the terminal device 4 makes a call to the terminal device 7, the local node device 2 to which the calling side terminal device 4 is connected sends a time slot request packet to acquire one time slot. Center node device 1
Send to.

The center node device 1 selects one free time slot and sends back to the local node device 2 a time slot assignment packet for granting the right to use it.

When the local node device 2 acquires the right to use one time slot, it transmits a call setup packet to the local node device 3 to which the called terminal device 7 is connected, and the local node device 3 receives this call setup packet. When the call is received, the call is made to the called terminal device 7, and when it is confirmed that the call can be set up based on the response of the called terminal device 7, a response packet is sent to the local node device 2, and the call is received in the allocated time slot. Notify that it is possible to set up a call to.

When the local node device 2 receives this response packet, the local node device 2 notifies the terminal device 4 that the call has been accepted, and thereafter, a circuit-switched call is set up via this assigned time slot, and the terminal device 4 Communication between devices 4.7 is now possible.

As shown in FIG. 4, a similar procedure is used to set up a circuit-switched call when the terminal equipment 5.8 communicates, and when the call is terminated, the management rights for that time slot are transferred to the center 7 node equipment. Return to 1.

Problems to be Solved by the Invention However, in the conventional circuit-switched channel allocation method described above, each time a call is made from a terminal device, the local node device to which the calling terminal device is connected is assigned to the center node device. On the other hand, a separate request packet for a circuit switched channel is sent, and after the allocation is completed, a call setup bucket is sent to the called party, so it takes a long time to set up a call, and there is still a load on the center node device 1. There is a problem with concentration.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to provide a circuit switching channel allocation method that can shorten the time for setting up a call and reduce the load on a center node device.

Means for Solving the Problems In order to achieve the above object, the present invention provides that when a terminal device makes a call for the first time after startup, a local node device receives the right to use a plurality of circuit switching channels from a center node device. 71 The local node device to which the calling terminal device is connected selects an empty channel from these multiple circuit-switched channels and initiates a call between the calling terminal device and the called terminal device. This is how you set it.

Effect of the Invention According to the above configuration, the local node device acquires the right to use a plurality of circuit switching channels from the center node device in advance. It is no longer necessary for the local node device to which the calling side terminal device is connected to send a circuit switching channel allocation request packet to the center node device. The load can be reduced.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing an embodiment of the sequence of the circuit switching channel allocation method according to the present invention.

In FIG. 1, when the terminal device 4 makes a call to the terminal device 7 for the first time after starting up the network, the local node device 2a to which the calling side terminal device 4 is connected receives, for example, five evening/time calls. Create a packet requesting a slot, identify the talk on the transmission path, overwrite the delimiter, packet data, and delimiter sequentially from the token part, send it to the center node device 1a, and finally send the new packet to the center node device 1a. send a token.

When the center node device 1a receives this time slot request/kukerato, it allocates 5 time slots if there is room to allocate 5 time slots, and if there is no room to allocate 5 time slots, it allocates 4 or less time slots. is assigned, a time slot assignment packet having the time slot number is created, 1.-kun on the transmission path is captured, and sent to the p-cal node device 2a.

When the device 2a acquires the right to use a plurality of time slots, the device 2a assigns the assigned one time slot number to the local node device 3a to which the called terminal device 7 is connected. Sends a call setup packet requesting call setup.

When the local node device 3a receives this call setup packet, the local node device 3a causes the called terminal device 7 to receive the call, and sends the call to the called terminal device 7.
When the response confirms that the call can be set up,
A response packet is transmitted to the local node device 2a to notify that a call can be set for the allocated time slot.

When the local node device 2a receives this response packet, the local node device 2a notifies the terminal device 4 that the call has been accepted, and thereafter sets up a circuit-switched call on i- via this assigned tights slot. This enables communication between the terminal devices 4 and 7.

Next, when the terminal device 5 connected to the local node device 2a makes a call to the terminal device 8, an empty time slot is selected from the already acquired time slots, and the local node to which the called terminal device 8 is connected selects an empty time slot from the already acquired time slots. A call setup packet having the selected time slot number 2 and requesting call setup is transmitted to the device 3a.

When the local node device 3a receives this call setup packet, it forwards the call to the called terminal device 8, and sends the call to the called terminal device 8.
After confirming that the call can be set up in response to
A response packet was sent to the local node device 2a and assigned. Notifies that it is possible to set up a call for the time slot.

When the local node device 2a receives this response packet, the local node device 2a notifies the terminal device 5 that the call has been accepted, and from then on, a circuit-switched call is set up via this assigned time slot, and the terminal Communication between devices 5 and 80 becomes possible.

Therefore, in this case, since the time slot request packet and the time slot assignment packet are not transmitted and received between the local node device 2a and the center node device 1a, a call can be set up in a short time.

Similarly, when, for example, a terminal device 6 connected to the local node device 2a makes a call to the terminal device 9, a time slot request packet and a time slot assignment packet are sent between the local node device 2a and the center node device 1a. Since no transmission or reception is performed, a call can be set up in a short time, except when the call is set up for the first time after startup.

Note that requests for evening time slots to the center node device 1a are made not only when there is an initial call request from terminal devices 4 to 9 after startup, but also when the number of time slots to be managed reaches 11. Also, when there is a call request from the terminal device, the time slot request packet and the time slot allocation packet are always not transmitted and received.

Note that the local node devices 2a and 3a request that the call be disconnected.
Since the number of free time slots managed by the center node device 1a increases, when a predetermined number of free time slots is reached, a time slot return packet is transmitted to the center node device 1a, thereby improving the efficiency of time slot use.

Effects of the Invention As explained in Section 2, the present invention enables a local node device to obtain the right to use a plurality of circuit switching channels from a center node device when a call is first made from a terminal device after startup. , the local node device to which the calling terminal device is connected selects an empty channel from these multiple circuit-switched channels and sets up a call between the calling terminal device and the called terminal device. , it is no longer necessary for the local node device to which the calling side terminal device is connected to send a circuit switching channel allocation request packet to the center node device every time there is a call from the terminal device, as in the conventional example. , the time for setting up a call can be shortened, and the load on the center node device can be reduced.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of the sequence of the line-switched channel allocation method according to the present invention, FIG. 2 is a block diagram showing a loop-type local area network, and FIG. , FIG. 2 is an explanatory diagram showing the structure of a frame transmitted on the loop type transmission path, and FIG. 4 is an explanatory diagram showing the sequence of a conventional circuit switching channel allocation method. 1a-=center node device (CN), 2a, 3a...
・Local node device

Claims (3)

[Claims] (1) When a call is first made from a terminal device after startup, the local node device acquires the right to use multiple circuit switching channels from the center node device, and the local node to which the calling terminal device is connected A circuit-switched channel allocation method in which a device selects an empty channel from the plurality of circuit-switched channels and sets up a call between a calling terminal and a called terminal. (2) The local node device acquires the right to use the plurality of circuit switched channels again from the center node device when the number of free channels of the circuit switched channels for which the right to use has been acquired becomes less than a predetermined number. The circuit switching channel allocation method according to claim 1, characterized in that: (3) The local node device returns the circuit switching channel to the center node device when the number of free channels for which it has acquired usage rights exceeds a predetermined number. The circuit switching channel allocation method described in (2).