JP3029881B2 - Time slot assignment method for slotted ring network - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time slot assignment method for allocating a time slot to each communication in a slotted ring communication network.

[0002]

2. Description of the Related Art In a slotted ring system, a frame of a fixed length always circulates on a ring, and each terminal connected to the ring carries data in a time slot obtained by dividing the frame into a fixed length. This is a method of communicating between each other. To give a concrete example, for example, go around the ring
Multiple frames are bundled together
When using a multi-frame,
Each frame is a time slot.
Equivalent to Which time slot is used by each terminal is fixedly assigned in advance at the time of system startup or system configuration change, etc., prior to its operation. Conventionally,
The time slot allocation has been manually performed in consideration of various conditions, or simply performed mechanically from the beginning of the frame by mechanical means without considering these conditions.

FIG. 3 is a diagram for explaining a conventional mechanical time slot reservation. Now, as shown in [A] of FIG. 3, one frame (for example, a multi-frame) has time slots (for example, thin slots ) of slot numbers # 0 to #m.
Frame numbers ) and slot numbers # 0 to #
2 has already been reserved for use by a specific communication, and it is assumed that the time slots of slot numbers # 3 to #m are empty slots.

In conventional mechanical time slot assignment, as shown in FIG. 3B, when time slot assignment is required for a certain communication, empty time slots are sequentially assigned from the beginning of a frame. A search is made to see if there is any, and if there is an empty time slot, it is mechanically assigned in order to that time slot.

[0005]

In recent years, communication networks have increased in complexity and communication definitions have been frequently changed. In the slotted ring system, it is necessary to reassign time slots for such changes.However, there are many restrictions on the time slot assignment rules. It is necessary to perform the assignment while referring to the definition information of and satisfying the following restrictions. Restriction example • The token slot must not use the 0th single frame. -The same single frame cannot be used in the same communication group.・ Do not transmit in the same single frame to the same receiving station.・ The number of time slots used for each communication definition is defined. Further, when there is an additional change in the communication definition, the assignment process becomes more complicated, so that the assignment by humans is very troublesome and the work time is long. In particular,
In a network where high reliability is required, it is necessary to prevent the network from going down for a long time due to such a change operation.

When the frame is mechanically allocated from the beginning of the frame by a mechanical means, the allocation is not always performed at a time slot position that satisfies the conditions sufficiently for all communications. Depending on the type of communication, communication may not be performed efficiently in the allocated time slot.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to automatically perform allocation in a short time without sufficiently lowering communication efficiency while sufficiently satisfying restrictions. It is to make.

[0008]

According to the present invention, there is provided a time slot assigning method for a slotted ring network, the method comprising the steps of:
The communication is classified into a plurality of communication groups according to its attributes, each communication group is assigned a priority based on the attribute, and in allocating time slots, the communication groups are sequentially selected in accordance with the priority , and the search target is searched. Times
The lot group is reserved for each of the plurality of communication groups.
A time slot search is performed while judging whether or not allocation conditions are satisfied from a predetermined search direction, and time slot allocation is automatically performed.

Further, the time slot assigning method for a slotted ring network according to the present invention, in the above method, requires a token group requiring a reservation time slot for performing burst communication and a plurality of time slots. High-speed group, and a low-speed group that requires a smaller number of time slots than the high-speed group, and the priority is assigned in the order of token group, high-speed group, and low-speed group. Things.

Further, in the time slot assignment method for a slotted ring network according to the present invention, in the second method, a token group is searched for a time slot from one of the search target time slot groups. The high-speed group and the low-speed group are searched from the direction opposite to the search direction of the token group.

[0011]

According to the time slot assignment method of the present invention, in a slotted ring type network, communications are classified into a plurality of communication groups according to their attributes, and the attributes of each communication group are assigned so that time slots can be allocated efficiently. In order to assign time slots, communication groups are sequentially selected in accordance with the priority order , and the search target
For the imslot group,
Time slot search is performed while judging whether or not the allocation condition is satisfied from a predetermined search direction, and time slot allocation is automatically performed. Thereby, the assignment can be performed efficiently in a short time.

As a method of classifying the communication groups, for example, as shown in FIG. 1, a token group requiring a reservation time slot for performing burst communication,
A high-speed group that requires multiple time slots,
By classifying into three communication groups, a low-speed group, which requires fewer time slots than the high-speed group, and assigning priority to the token group, the high-speed group, and the low-speed group in this order, An optimal time slot can be efficiently searched.

When searching for a time slot, for example, as shown in FIG. 2, a time slot search is performed from one direction of a time slot group to be searched for a token group, and a high-speed group and a low-speed group are searched for. If the search is performed from the direction opposite to the search direction of the token group, the collision between the two is reduced, and the search can be performed efficiently.

An embodiment of the present invention will be described below with reference to the drawings. In Slotted ring system network used in this embodiment, as shown in FIG. 2, to a cyclic ring
Frame (for example, a multi-frame) has a slot number #
0 to #m (m + 1) time slots (for example,
This time slot is divided into 0 layers
Not multiplex (n + 1) packets from
You. In other words, one time slot (one single frame)
Packets and the like are multiplexed by (n + 1) bytes, where
Refers to a set of data for each packet as a “layer”.
are doing. It is assumed that a monitoring node and other nodes are connected on the ring.

First, it is defined that the communication of each terminal on the slotted ring network is classified into three types, a token group, a high-speed group, and a low-speed group, according to their attributes. The definition of each group is as follows.

Token group definition: A group that requires a reserved slot for performing burst communication. In this group, a predetermined number or more of empty time slots for performing burst communication are required below the time slot containing the token. The number of empty time slots to be used depends on the content of burst communication. That is, the number of empty time slots to be used is not fixed. The empty time slots need not be consecutive. High-speed group definition: A group that requires multiple time slots. This is a communication with a large amount of data such as image communication, and a certain number of time slots are used for one path (frame). Low-speed group definition: A group that requires fewer time slots than the high-speed group. For example, this is a group that requires only one time slot, and is general communication such as voice communication.

For example, the following related restrictions are added to each of these groups. · Booking position [related restrictions of the token group] is single-frame (time slot) # 1
To # 7.・ Single frame after token slot needs 24 free time slots. [Restrictions related to high-speed system group]-There must be no more than one slot used in one lineset in the same single frame. [Restrictions related to low-speed system groups]-When one slot is shared by multiple line sets, it cannot be shared by line sets in the same node. -The same lineset must not receive more than one slot in the same single frame.

The communication groups defined as described above are allocated time slots according to the processing procedure of FIG. The time slot search order of each communication group at the time of the time slot allocation is performed as shown in FIG. In addition,
This time slot allocation is performed by software at the monitoring node of the network. When the operator of the monitoring node inputs the system configuration and the communication definition, the allocation device acquires the definition information, and determines the optimum time based on the definition information. Time slots are automatically reserved.

First, it is determined whether or not a reserved time slot in each layer is stored (step S1). If not saved, all time slots are re-allocated, so that all time slots including reserved time slots are released and all time slots are set as empty time slots (step S2). On the other hand, when saving, a part of time slot allocation is changed, and in this case, a time slot that has been canceled due to the change among the reserved time slots is released to make it an empty time slot. (Step S3).

Next, the time slot allocation target communication is checked to determine whether there is a communication belonging to the token group, that is, whether the reservation of the token slot is necessary (step S4). If a token slot needs to be reserved, it is checked by time slot search whether there is an empty slot that satisfies the condition (that is, the related restrictions on the token group) (step S).
5).

In this time slot search, as shown in FIG. 2, when the slot number becomes # 7 for the first time from the slot number # 1 of the 0th layer, the process proceeds to the next layer and the search is sequentially performed from the slot number # 1. Is performed up to the n-th layer. When a time slot satisfying the condition is retrieved, it is reserved as a token slot (step S6).
Such processing is performed for all communications belonging to the token group.

If there is no communication belonging to the token group, or if all the reservations of the communication belonging to the token group have been completed, it is determined whether there is a communication belonging to the next high-speed group, that is, whether a high-speed slot needs to be reserved. It is checked whether or not it is (step S7). If you need a reservation,
A time slot search is performed to determine whether or not there is a slot that satisfies the condition (ie, the high-speed group related restriction) (step S8).

This time slot search is performed in a direction opposite to the search direction of the time slot search for the token group. In other words, the search is performed for the first time from the last time slot of the slot number #m of the n-th layer.
After retrieving up to the (n-1) th layer, the process proceeds to the last time slot of the (n-1) th layer, and the same search is performed. This is repeated up to the 0th layer. When a time slot that satisfies the condition is found, the slot is reserved (step S9).

Further, when there is no communication belonging to the high-speed system group, or when all the reservations of the communication belonging to the high-speed system group are completed, it is determined whether there is communication next belonging to the low-speed system group, that is, the low-speed slot It is checked whether a reservation is necessary (step S10). If a reservation is required, the conditions (ie the relevant restrictions for the slow group)
A time slot search is performed to determine whether there is a slot that satisfies (step S11). In this case, the time slot search order is the same as in the case of the high-speed group. When a slot satisfying the condition is searched, the slot is reserved (step S12).

The time slot allocation is performed as described above. If it is determined that there is no time slot satisfying the condition as a result of the determination of the condition of each group (NO in steps S5, S8, S11), the time slot is allocated. If the time slot is allocated by only releasing unused time slots, all time slots are released (step S2), and time slot allocation is performed again.

When time slot allocation is performed as described above, first, the communication of the token group, which is considered to be the most difficult to satisfy the condition, is performed when the number of available time slots is large, that is, when the condition is easily satisfied. The slot is searched and reserved, and then the communication of the high-speed group, which is considered to be the second most difficult to satisfy the condition, is searched and reserved for the time slot. Finally, it is easiest to satisfy the condition. The communication of the low-speed system group which is considered to be time slot searched is reserved.

Since the search for the token group and the search for the high-speed system and the low-speed system group are performed in opposite directions, the condition of each group can be easily satisfied also in this respect.

When time slot allocation is completed in the monitoring node as described above, the allocation result is set in each node of the network. This setting method may be automatically performed by download communication via a network, or may be manually set by manually distributing a floppy disk or the like storing the allocation result to each node. When the time slot allocation result is set to all nodes of the network, communication is performed using the time slot according to the allocation.

In carrying out the present invention, various modifications are possible. For example, in the above-described embodiment, the time slot allocation is performed by the monitoring node of the network. However, the present invention is not limited to this. Of course, the allocation is performed in a place other than the node, and the result is obtained. It may be set in each node of the network.
The classification of the communication groups according to the attributes of the communication is not limited to the three types of tokens, high-speed systems, and low-speed systems in the embodiment, and a classification method based on another definition is also possible according to the type of communication.

[0030]

As described above, according to the present invention, even when the communication definition changes frequently, for example,
The system administrator only needs to consider the communication definition and related restrictions, eliminating the need for time-consuming and complicated time slot assignment by hand, and dramatically reducing the processing time required for time slot assignment. . In addition, since each communication is assigned to an optimal time slot position in consideration of its attribute, communication efficiency is improved during system operation. As described above, it is possible to quickly respond to a change in the system configuration and the like, which greatly contributes to improving the maintainability of the system.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a time slot allocation procedure according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a time slot search order for time slot allocation according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a conventional mechanical slot reservation.

[Explanation of symbols]

 0 to n layer number # 1 to #m slot number

Continuation of the front page (56) References JP-A-63-26051 (JP, A) JP-A-58-25742 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12 / 42

Claims (3)

(57) [Claims] In a slotted ring network, communications are classified into a plurality of communication groups according to their attributes, and priorities are assigned to the respective communication groups based on the attributes. sequentially select the communication group in accordance with, searched
For the time slots, the plurality of communication groups
A time slot assignment method for a slotted ring network in which time slot search is performed while determining whether or not allocation conditions are satisfied from predetermined search directions . 2. A token group requiring a reservation time slot for performing burst communication, a high-speed group requiring a plurality of time slots, and a low-speed group requiring fewer time slots than the high-speed group. Are divided into three communication groups, token groups,
2. The time slot assignment method for a slotted ring network according to claim 1, wherein priorities are assigned in the order of a high-speed group and a low-speed group. 3. A time slot search is performed for the token group from one of the search target time slot groups, and a high-speed group and a low-speed group are searched in a direction opposite to the search direction of the token group. 3. The time slot assignment method for a slotted ring network according to claim 2, wherein