JPH0221745A - Line time slot assignment method - Google Patents

Abstract

PURPOSE:To reduce the time for setting a call and to relieve the load of a center node equipment by allowing the center node equipment to allocate the right of use of plural time slots to a local node equipment. CONSTITUTION:The local node equipment LN acquires the right of use of plural time slots from the center node equipment CN. Every time a call comes from a terminal equipment TE, it is not required for the local node equipment LN connected to a caller terminal equipment TE sends an allocation request packet of a time slot to the center node equipment CN. Thus, the time 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 method for allocating line time slots for circuit switching on a local area network (LAN).

BACKGROUND ART FIG. 4 shows a loop-type local area network, in which 11 is a center node device (CN) that accommodates terminal devices (TE) 15 and 16 and manages the entire network; 12, 13, and 14 are local node devices (LN) for accommodating terminal devices (TE) 17 to 22 and subnetworks (not shown) in this local area network, and in this example, the local node device 12 houses the terminal device 17.18,
Local node device 13 accommodates terminal device 19.20, and local node device 14 accommodates terminal device 21.22.

FIG. 5 shows a conventional method of allocating line time slots.

4 and 5, for example, when the terminal device 17 makes a call to the terminal device 19 (sequence 5Q1), the local node device 12 to which the calling side terminal device 17 is connected
transmits a time slot request packet to the center node device 11 in order to acquire one time slot (SQ2).

The center node device 11 selects one free time slot and returns a time slot allocation packet for granting the right to use it to the local node device 12 (SQ3
).

When the local node device 12 acquires the right to use one time slot, it transmits a call setup packet to the local node device 13 to which the called terminal device 19 is connected (5Q4), and the local node device 13 accepts this call. When the setting packet is received, the called terminal device 19 receives the call (S
Q5) When it is confirmed by the response (SQ6) from the called terminal device 19 that the call can be set up, a response packet is sent to the local node device 12. Notify that settings are possible.

When the local node device 12 receives this response packet, it notifies the terminal device 17 that the call has been accepted (5Q8), and from then on, a circuit-switched call is set up via this assigned time slot. , terminal device 17
．． 19 becomes possible (SQ9).

Note that when communication is to be performed between other terminal devices, a circuit switched call is set up using a similar procedure, and when the call is terminated, the management right of the time slot is returned to the center node device 11.

Problems to be Solved by the Invention However, in the conventional line time slot 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 11.
A time slot allocation request packet is sent to the called party, and after the allocation is completed, a call setup packet is sent to the called party, so it takes a long time to set up a call, and the load is concentrated on the center node device 11. There is a problem.

SUMMARY OF THE INVENTION In view of the above conventional problems, it is an object of the present invention to provide a line time slot 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 allocates the right to use a plurality of time slots to the local node device in advance by the center node device to the local node device to which the calling side terminal device is connected. The node device selects an empty time slot from the plurality of time slots and sets up a call between the calling terminal device and the called terminal device.

Operation According to the present invention, with the above configuration, the local node device acquires the right to use a plurality of time slots from the center node device in advance, so that every time a call is made from a terminal device as in the conventional example, the calling side terminal It is no longer necessary for the local node device to which the device is connected to send a time slot allocation request packet to the center node device, thus reducing the time required to set up a call and reducing the load on the center node device. be able to.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a local area network that performs communication using an embodiment of the time slot allocation method according to the present invention, and FIG. 2 shows the structure of a frame transmitted on the loop-type transmission path of FIG. 1. FIG. 3 is an explanatory diagram showing an example of the sequence of the time slot allocation method according to the present invention.

In FIG. 1, 1 is a center node device (CN) that accommodates terminal devices (TE) 5.6 and manages the entire network, and 2.3.4 are terminal devices (TE) 7 to 10, respectively. This is a local node device (LN) for accommodating a subnetwork (not shown) in this local area network. In this example, local node device 2 accommodates a terminal device 7.8, and local node device 3 accommodates a terminal device 7.8. It houses equipment 9.10.

Each of the node devices 1 to 4 has a line switching function and a packet switching function, and call connection processing for line switching is performed by packet switching.

In Figure 2, one frame consists of a frame header (FH
), circuit switching area and packet switching area,
The circuit switching area consists of time slots TS1 to TSn to be allocated to each circuit switching channel, and the packet switching area consists of each packet data and a delimiter identification code (called a delimiter) provided at the beginning and end of this packet data. SD, ED) and a transmission right identification code called a token, which is provided at the beginning of the next area where packet data can be written.When transmitting packet data, the token on the loop is identified and the token is The delimiter, packet data, and delimiter are sent sequentially starting from , overwriting the delimiter, and finally a new token is sent.

Next, the operation of the above embodiment will be explained.

In FIGS. 1 and 3, after starting up the network, the center node device 1 connects each local node device 2 to
The right to use a plurality of time slots is allocated to each of the four time slots (SQII).

Next, for example, when the terminal device 7 makes a call to the terminal device 9 (SQ12), the local node device 2 to which the calling terminal device 7 is connected is connected to the local node device 3 to which the called terminal device 9 is connected. A call setup packet having one assigned time slot number and requesting call setup is transmitted to the call setup packet (SQ13).

When the local node device 3 receives this call setup packet, it sends the call to the called terminal device 9 (SQ14), and confirms that the call can be set up by the response of the called terminal device 9 (SQ15). Then, it transmits a response packet to the local node device 2 (SQ16), notifying it that it is possible to set up a call for the allocated time slot.

When the local node device 2 receives this response packet, it notifies the terminal device 7 that the call has been accepted (5Q17), and from then on, a circuit-switched call is set via this allocated time slot. , communication between the terminal devices 7 and 9 becomes possible (SQ 18).

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 2 and the center node device 10, a call can be set up in a short time.

Note that the local node device is different from the center node device 1.
When the number of time slots to manage reaches "1", a time slot is requested (5Q19.20), and a time slot request packet and a time slot allocation packet are always sent and received when there is a call request from a terminal device. Make sure not to.

Note that when the call is disconnected, the number of free time slots managed by the local node devices 2 to 4 increases, so when a predetermined number of free time slots is reached, a time slot return packet is sent to the center node device 1. to improve time slot usage efficiency.

As described in detail, the present invention is such that a center node device allocates the right to use a plurality of time slots to local node devices in advance, and the local node device to which the calling side terminal device is connected Since a vacant channel is selected from multiple circuit-switched channels and a call is set up between the calling terminal device and the called terminal device, each time a call is made from the terminal device, unlike in the conventional case, This eliminates the need 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 on the node device can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a low-power area network that performs communication using an embodiment of the time slot allocation method according to the present invention, and FIG. FIG. 3 is an explanatory diagram showing an example of the sequence of the time slot allocation method according to the present invention. FIG. 4 is a block diagram showing a conventional local area network. FIG. FIG. 2 is an explanatory diagram showing a sequence of a conventional line time slot allocation method. 1... Center node device (CN), 2. 3. 4
... Local node device (LN), 7 to 10... Terminal device (TE). ,L is the name of the agent Patent attorney Shigetaka Awano and 1 other person 5,'
Figure 5

Claims (4)

[Claims] (1) The center node device allocates the right to use multiple time slots to the local node device in advance, and the local node device to which the calling side terminal device is connected selects an empty time slot from these multiple time slots and makes a call. A line time slot allocation method for setting up a call between a calling terminal and a called terminal. (2) The line time slot allocation method according to claim 1, wherein the center node device allocates the right to use a plurality of time slots to the local node device after startup. (3) The local node device acquires the right to use a plurality of time slots again from the center node device when the number of vacant time slots of the time slots for which the right to use has been acquired becomes less than a predetermined number. The line time slot allocation method according to claim (1) or (2). (4) The local node device returns the time slots to the center node device when the number of vacant time slots for which the right to use has been acquired exceeds a predetermined number. The line time slot allocation method according to any one of 3).