JPH06261067A - Method and device for controlling variable virtual path capacity - Google Patents

Abstract

PURPOSE:To obtain a VP capacity variable controller in which a VP capacity control processing quantity is reduced and no impartial processing quantity in each VP relay node takes place in discrete control. CONSTITUTION:Upon the receipt of call occurrence information S1, a call reception control section 1 writes a band width and a VP number in a call reception management memory 2 and outputs a band allocation/release request S4 to a VP capacity control section 3 to allocate a VP capacity. The VP capacity control section 3 decides the propriety of call reception and writes variables used for the VP capacity control section 3 in a band management memory 4 when the reception enable is discriminated and controls the VP capacity to provide an output of result of the propriety of band allocation with respect to a call to the call reception control section 1. When the end of call information S2 is inputted to the call reception control section 1, the band width and the VP number are read from the call reception management memory 2 and outputs a band allocation/release request S4 to the VP capacity control section 3 so as to release the revised capacity from the VP capacity in which the call is allocated.

Description

Detailed Description of the Invention

[0001]

This invention relates to a switching / transmission system,
Especially Asynchronous Transfer Mode-
The present invention relates to a virtual path capacity control method in a switching / transmission system using ATM.

[0002]

2. Description of the Related Art In a switching / transmission system using ATM, a logical path (link) defined by a switching agency.
Is called a virtual path (hereinafter VP). In the above system, information is transferred by a fixed-length packet called a cell, and switching is performed for each cell based on the label information corresponding to the VP added to the cell to establish a path. Therefore, it is based on time slot conversion. Compared to circuit switching / transmission systems, variable capacity control becomes easier. Therefore, AT
In the switching / transmission system using M, by adaptively changing the allocation of the physical transmission line capacity to each VP, the fluctuation of traffic added to the path is absorbed and the transmission line is efficiently used. It becomes possible to do it.

Conventionally, as a method for controlling the adaptive allocation of the physical transmission line capacity to the VP, "Virtual path capacity control algorithm in a large-scale ATM network", Proc. 3, third ~
Some were suggested on page 247. First, the part where the physical transmission line capacity is occupied by each VP (VP capacity)
And a portion not occupied by any VP (transmission line free capacity), and a portion occupied by a call that has already accepted the VP capacity and a portion not occupied by any call (VP Free space) and divide. VP
When a call occurs in the VP, the VP free capacity of the VP that should accommodate the call is checked, and if the VP free capacity is insufficient, the VP capacity is increased by a predetermined value S (capacity change amount) so that the transmission path is free. The capacity is exchanged from the capacity to the VP.

When the call ends from the VP, the increased VP free capacity is compared with the capacity change amount S. If the VP free capacity is larger than the capacity change amount S, the VP capacity is reduced by the capacity change amount S. By making the capacity change amount equal to the bandwidth of the call having the smallest bandwidth, the VP capacity is changed each time a call of the VP is generated or terminated, so that the VP free capacity is always zero. However, if the above capacity changing process is performed every time a call is generated and terminated, a large amount of processing capacity is required to control a large number of VPs, which makes implementation difficult. Therefore, by setting the capacity change amount S to a certain large value, the use efficiency of the transmission path is slightly lowered, but the number of VP capacity changes per unit time can be kept within the capacity range of the processing device. .

In the above document, the capacity change amount S is determined by the following procedure. For each predetermined time T, the sum P of the number of capacity changes of all VPs within the time T, and the allowable number of capacity changes Pli that can be processed within the processing capacity of the processing device.
m is compared, if P <Plim, the capacity change amount of the VP having the smallest VP free capacity is reduced by a predetermined value, and if P ≧ Plim, the VP free capacity is the largest V
The capacity change amount S of P is increased by a predetermined value. This is a control that assumes a correlation between the size relationship of the number of times of capacity change between each VP and the size relationship of the VP free capacity between each VP.

By performing the above processing, the capacities of a plurality of virtual paths are adaptively controlled under a constant processing capacity, the flexibility of the communication network with respect to fluctuations in traffic is improved, and the efficiency of the transmission path is improved. It was possible to use it.

[0007]

However, in the method described above, it is assumed that there is a correlation between the VP capacity change count per unit time between each VP and the VP free space relationship between each VP. Therefore, in a multimedia environment in which calls with different speeds and hold times are added, the above assumption changes, and it becomes impossible to adaptively control the capacity of multiple virtual paths under a certain processing capacity. There is. This is because the VP having a large VP free capacity does not always have a small number of capacity changes when the speeds of calls accommodated are different.

[0008] Further, it is activated by the excess or deficiency of the VP free capacity detected at the VP terminal node, sends a VP capacity change request from the VP terminal node to each VP relay node through which the VP passes, and each VP relay node receives When it is applied to the distributed control that determines whether to permit or disallow according to the available transmission line capacity of the VP, the amount of capacity change must be determined by each VP terminating node. In this case, since the VP capacity change amount is determined only by the VP capacity change frequency information in each VP end node, each VP relay node accommodating VPs from a plurality of VP end nodes has a large amount of VP capacity control processing amount. There has been a problem in that the processing capacity of each relay node cannot be estimated because the deviation may occur.

Therefore, the present invention eliminates the above-mentioned problems, controls the VP capacity control processing amount to a predetermined processing amount or less even in a multimedia environment, and each VP relay also in distributed control. It is an object of the present invention to provide a virtual path capacity variable control method and its apparatus that do not cause a large deviation in the processing amount at a node.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a switching / transmission system, in particular, in the switching / transmission system utilizing an asynchronous transfer mode, in controlling the VP capacity, each VP within a fixed time. Capacity change count comparing means for comparing the capacity change count of the processor with a single predetermined threshold value in the system based on the capacity change processing capacity of the processing device, and the capacity change count comparing means for outputting the comparison result; When the number-of-times comparison unit determines that the number of times the capacity of the VP is changed is equal to or larger than the threshold value, the capacity change amount coefficient of the VP is incremented by 1, and the number of times of the capacity change is determined to be less than the threshold value. In this case, the capacity change coefficient updating means for decreasing the capacity change quantity coefficient of the VP by one, and when the VP capacity is insufficient, the capacity is increased by a value obtained by multiplying the capacity change coefficient by a predetermined value, When the P free capacity exceeds the value obtained by multiplying the capacity change coefficient by a predetermined value, the capacity changing means releases the capacity by a value obtained by multiplying the capacity change coefficient by a predetermined value, and the VP capacity variable control is performed. Configured method.

Also, the identification number of the generated call, the bandwidth, and the VP number that should accommodate the call are received as the call generation information S1.
A call admission control unit 1 that outputs a bandwidth allocation / release request S4;
In response to the bandwidth allocation / release request S4, whether to accept the call is determined according to the VP capacity variable control method, and the bandwidth is set to V
The VP capacity control is performed so as to allocate or release the P capacity, and the result of the band allocation availability for the call is output to the call admission control unit 1 as the admission availability signal S3.
The P capacity control unit 3 and the call reception management memory 2 that stores the VP number and the bandwidth corresponding to the identification number of the call when the VP capacity control unit 3 determines that the call can be accepted.
And hold each variable used in the VP capacity control unit 3,
A virtual path capacity variable control device is composed of the band management memory 4 which is read and written by the capacity control unit 3.

[0012]

According to the VP capacity variable control method of the present invention, the VP capacity variable frequency comparison means allows each VP to be operated within a fixed time.
The number of times the capacity is changed is compared with a single predetermined threshold value in the system based on the capacity change processing capacity of the processing device. Then, as a result of the comparison, when it is determined that the capacity change count of the VP is equal to or larger than the threshold value, the capacity change coefficient updating unit adds 1 to the capacity change amount coefficient of the VP, and the capacity change count is the threshold value. When it is determined that it is less than 1, the capacity change amount coefficient of the VP is decremented by 1. Then, if the VP capacity is insufficient by the capacity changing means, the capacity is increased by a value obtained by multiplying the capacity changing coefficient by a predetermined value, and the VP free capacity is predetermined as the capacity changing coefficient. When the value multiplied by the value is exceeded, the capacity is released by the value obtained by multiplying the capacity change coefficient by a predetermined value.

Further, according to the VP capacity variable control device, the call admission control unit 1 receives the call generation information S1 and outputs a bandwidth allocation / release request S4 to the VP capacity control unit 3. The VP capacity control unit 3 performs the above control to determine whether or not bandwidth allocation is possible,
If it is possible, the bandwidth is allocated to the VP capacity, and the result of acceptance or non-approval of bandwidth for the call is accepted or rejected signal S3.
Is output to the call admission control unit 1. At this time, the VP number and the bandwidth corresponding to the identification number of the call are stored in the call reception management memory 2. Further, each variable used in the VP capacity control unit 3 is held in the band management memory 4, and read or written by the VP capacity control unit 3 as needed.

As described above, for the VP for which it is determined by the capacity change number comparison means that the capacity change number Mi is large, the capacity change coefficient Si is controlled to be larger and the VP free space Ri is larger, and vice versa. For a VP determined to have a small number of times Mi of capacity change, the capacity change coefficient Si
Becomes smaller. Further, since the threshold value Mth takes a single value in the system, the capacity change count Mi of each VP becomes constant in the system, and even when distributed control is used for VP capacity control, the processing amount of the VP relay node is increased. Is proportional to the number of VPs passing through the VP relay node, so the processing amount can be easily calculated.

[0015]

Embodiments of the VP capacity control method according to the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing a VP capacity control device.

In FIG. 1, when a call is generated, the identification number of the generated call, the bandwidth, and the VP number that should accommodate the call are used as the call generation information S1, and the identification number of the call that ended the call is used as the call termination information S2. Is input to the call admission control unit 1.

When the call admission control unit 1 receives the call origination information S1, it determines whether or not to accept the call. Therefore, the bandwidth obtained from the call origination information S1 is used in the same manner as the call origination information S1.
It is output to the VP capacity control unit 3 as a bandwidth allocation / release request S4 so as to be allocated to the VP capacity of the VP number obtained from. Further, when the call acceptance / rejection signal S3 output from the VP capacity control unit 3 determines that the call is acceptable, the VP number and the VP number corresponding to the identification number of the call determined to be acceptable by S5 passing through the bus B1 are stored. The bandwidth is stored in the call admission management memory 2. On the other hand, when the call end information S2 is input to the call admission control unit 1, the bandwidth and VP number corresponding to the identification number obtained from the call end information S2 are read from the call admission management memory 2 by S5 passing through the bus B1. A bandwidth allocation / release request S4 is output to the VP capacity control unit 3 so as to release the bandwidth corresponding to the identification number from the VP capacity of the VP number in which the issued and terminated call was accommodated.

The VP capacity control unit 3 controls the VP capacity according to the bandwidth allocation / release request S4 output from the call admission control unit 1, and the call admission control unit 1 outputs the result of admission / denial of bandwidth to the call as an admission / denial signal S3. And output to the outside.

If the bandwidth allocation / release request S4 requests bandwidth allocation, the processing according to the flowchart shown in FIG. 2 is performed. First, the bandwidth Wk of the call generated in the VP number i is compared with the VP free capacity Ri of the VP number i,
If Ri <Wk, the VP empty capacity is insufficient, so the capacity is accommodated from the transmission path empty capacity E to the VP capacity of the VP number i. Therefore, the transmission path empty capacity E and the capacity change amount (Si × C)
And is compared to determine whether capacity can be accommodated. In order to simplify the VP capacity control process, the capacity change amount is represented by the product of the capacity change amount coefficient Si different for each VP and the unit capacity change width C which is a single value in the system. If the capacity can be accommodated, the transmission path free capacity E to the VP free capacity Ri
The capacity change counter Mi for counting the number of capacity changes is incremented by one. If the capacity cannot be accommodated, it is determined that the call cannot be accepted, and the acceptance is not permitted by the acceptance permission signal S3. If the capacity can be accommodated, or if Ri ≧ Wk, it is determined that the call can be accepted, Wk is subtracted from the VP free capacity Ri, and acceptance is instructed by the acceptance availability signal S3.

Next, if the bandwidth allocation / release request S4 is a request to release the bandwidth, the processing according to the flowchart shown in FIG. 3 is performed. First, Wk is added to the VP free capacity Ri of the VP number i, and then Ri and the capacity change amount (Si
* C) is compared. If Ri> (Si × C), VP
The capacity is exchanged from the free capacity Ri to the transmission path free capacity E.
At the same time, the capacity change number counter Mi for counting the number of capacity changes is incremented by one. If Ri ≦ (Si × C), the capacity is not accommodated, and the process ends.

Further, in the VP capacity control unit 3, all the VPs are processed by the processing according to the flowchart shown in FIG.
The capacity change amount coefficient of is updated. This is the same as setting the total number of VPs to N and processing one VP every time T / N. When updating the capacity change amount coefficient of the VP number i, as shown in FIG. 4, the number of times of capacity change Mi in the time T is compared with the threshold value Mth which is a single value in the system,
If Mi <Mth, 1 is added to Si, and if Mi ≦ Mth, 1 is subtracted from Si. Further, Mi is cleared to 0 in order to count the number of times the capacity is changed in the next time T. Since the fixed time period T is selected from several tens of minutes to several hours, the capacity change amount coefficient update processing amount per unit time is extremely small.

The band management memory 4 holds the variables E, Ri, Si and Mi used in the VP capacity control section 3 and stores them in the VP.
In accordance with an instruction from the capacity control unit 3, the VP capacity control unit 3 reads or writes via S6 passing through the bus B2.

[0023]

As described above, according to the method and apparatus of the present invention, the VP free capacity is controlled to be larger for a VP with a large number of capacity changes, and the capacity change set for each VP is changed. The amount is finally updated so that the number of times the capacity is changed per time T becomes a constant value Mth. Therefore, even in a multimedia environment in which calls with different speeds and hold times are added to each VP, a certain processing capacity is maintained. It is possible to adaptively control the capacities of a plurality of VPs.

Further, since Mth takes a single value in the system, the number of times the capacity of each VP is changed is constant in the system, and even when distributed control of the VP capacity is performed, the processing amount of the VP relay node is the same. Since it is proportional to the number of VPs passing through the relay node, the processing amount can be easily calculated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a virtual path capacity variable control device according to the present invention.

FIG. 2 is a flowchart showing a VP capacity control process upon arrival of a call.

FIG. 3 is a flowchart showing a VP capacity control process when a call is withdrawn.

FIG. 4 is a flowchart showing an update process of a VP capacity change amount count.

[Explanation of symbols]

 1 call admission control unit 2 call admission management memory 3 VP capacity control unit 4 band management memory S1 call generation information S2 call end information S3 admission acceptance signal S4 band allocation / release request

Claims (2)

[Claims] 1. In the control of virtual path capacity in a switching / transmission system, particularly in a switching / transmission system using an asynchronous transfer mode, the number of times the capacity of each virtual path is changed within a fixed time and the capacity change processing capacity of a processing device are controlled. Based on a single predetermined threshold value in the system, the capacity change count comparison means for outputting the comparison result and the capacity change count comparison means are used to determine the capacity change count of the virtual path. If it is determined to be above the threshold value,
A capacity change coefficient updating means for reducing the capacity change quantity coefficient of the virtual path by 1 when the capacity change quantity coefficient of the virtual path is incremented by 1 and the capacity change count is determined to be less than a threshold value; When the virtual path free capacity exceeds the value obtained by multiplying the capacity change coefficient by a predetermined value, the capacity is increased by a value obtained by multiplying the capacity change coefficient by a predetermined value. A capacity change amount variable control method comprising: a capacity change means for releasing a capacity by a value obtained by multiplying a change coefficient by a predetermined value. 2. A call admission control unit that receives, as call generation information, an identification number of a generated call, a bandwidth, and a virtual path number that should accommodate the call, and outputs a bandwidth allocation / release request, and a bandwidth allocation / release request. In response to the virtual path capacity variable control method according to claim 1, whether or not to accept the call is determined, the virtual path capacity is controlled so that the bandwidth is allocated to the virtual path capacity or released, and the bandwidth is allocated to the call. A virtual path capacity control unit that outputs the acceptance result as a reception acceptance signal to the call admission control unit, and a virtual path corresponding to the identification number of the call when the virtual path capacity control unit determines that the call can be accepted. Holds the call admission management memory that stores the path number and bandwidth, and each variable used in the virtual path capacity control unit,
A virtual path capacity variable control device comprising: a band management memory which is read and written by a virtual path capacity control unit.