JP2780537B2 - Call admission control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an ATM (Asynch).
The present invention relates to a call admission control method for determining whether or not a room (Roadless Transfer Mode) network can accept a call originated from a user based on information declared by the user and determining whether to accept the call. Things.

[0002]

2. Description of the Related Art In a broadband ISDN network, a conventional synchronous transfer method (STM; Synchronous Tra) is used.
nsfer Mode) and an asynchronous transfer method (AT
M; Asynchronous Transfer M
mode), digital signal transmission is performed, and C
Standardization is underway at CITT (International Telegraph and Telephone Advisory Committee). In an ATM network, in order to multiplex multimedia information having different characteristics such as voice, data, and image, and to perform high-speed transmission, call admission control, that is, whether or not the network has room to accept a call originated by the user is determined by the user. It is necessary to make a decision based on the information reported from the company and determine whether to accept the call.

FIG. 3 shows a two-state ON / OFF model representing burst traffic in an ATM network under the above control. In the figure, 11 is an ATM cell, 12 is an ATM cell
Section of the ON state in which cells occur at TM (J) intervals, 13
Is an OFF state section in which no cells are generated. In the two-state ON / OFF model, it is assumed that cells occur at TM (J) intervals only in the ON state section 12 at the time T1 (J) and do not occur in the OFF state section 13. O
It is assumed that the N state 12 and the OFF state 13 are repeated in a cycle T2 (J).

[0004] A user calls his / her outgoing call as shown in FIG.
The parameters T1 (J), T2 (J), and TM (J) when modeled in the state ON / OFF model are declared directly or indirectly. The ATM network uses the parameters T1 (J), T2 (J), TM based on the information declared by the user.
(J) is calculated, and call admission control is performed based on this.

[0005] FIG. 15 is a diagram showing a call admission judgment for judging whether or not the network has room to accept a call originated from the user based on information declared by the user in the ATM network. It is a flowchart of the conventional example of an algorithm. In the figure, a burst overflow rate BT is calculated based on parameters declared by a user in step (ST3). At step (ST4), it is determined whether or not the burst overflow rate BT is equal to or less than a specified value. If the BT is equal to or less than the specified value, no overflow occurs even if the call is accepted, so that call acceptance is permitted (step (ST2)). If the BT takes a positive value, the call is accepted and the call acceptance is rejected because overflow occurs (step (ST6)).

That is, the decision of rejection of the call is made based on whether or not the value of the burst overflow rate BT is equal to or less than a specified value. A conventional method of calculating the burst overflow rate is described in, for example, IEICE Technical Report IN89-7, "A Study of Burst Traffic Queue Length Distribution" (Sato, Tanabe, Suzuki). This is shown in the flowchart of FIG.

First, parameters used in these flowcharts will be described. J represents the type of call (call type). Since there are L types in total, J takes an integer value of 1 ≦ J ≦ L. The number of calls of the call type J is N (J), and the number of calls in the ON state 12 in FIG. 3 is I (J). The ratio of the ON state 12 in FIG. 3, that is, T1 (J) / T2 (J)
As R (J). In addition, the cell arrival speed V in the ON state
M (J) is the reciprocal 1 / TM (J) of the cell arrival interval TM (J) in the ON state. BT is the burst overflow rate mentioned above,
ρ is the amount of cell traffic.

FIG. 16 is a flowchart of a conventional burst overflow rate BT calculation, which is the contents of the step (ST3) in FIGS . 9 and 15 . Step (ST101),
In (ST102) and (ST103), the value of the call type J is set to 1 ≦ J
≦ L, and the steps (ST104), (S104)
T105), (number of calls in the one call type J to O N state of FIG. 3 in ST 106) I (J) of 0 ≦ I (J) ≦ N
N (L) +1 changes are made in the range of (J), and in each case, an expected value EPT of burst overflow is calculated in step (ST107) and cumulatively added.

Here, the step (ST107) is

[0010]

(Equation 1)

[0011] It will go round. Thereafter, the step (S
In T108), the cell traffic amount ρ is calculated, and in step (ST109), the burst overflow expected value EPT, which has been cumulatively added, is divided by the cell traffic amount ρ to obtain a burst overflow ratio BT = EPT / ρ.

FIG. 17 shows the steps (ST107) of FIG.
7 is a flowchart of calculation of the contents of bursts, that is, the expected value EPT of burst overflow, and cumulative addition. First, the step (ST
At 110), the total SUM of the number of arrival cells is calculated. Next, in step (ST111), it is determined whether or not SUM overflows 1, that is, whether or not burst overflow occurs.
If the burst overflow does not occur at 1 and the value of EPT is not changed, and if the burst overflow occurs at SUM> 1, at step (ST112), the occurrence probability PR of the SUM is determined.
B is calculated, and in step (ST113) the overflow SUM−
The expected burst overflow value EPT is updated by adding the product of 1 and the occurrence probability PRB, that is, the increment of the expected value of burst overflow to the current expected value of burst overflow EPT.

FIG. 18 shows the steps (ST110) of FIG.
9 is a flowchart of calculating the contents SUM, that is, the total SUM of the number of arrival cells. Step (ST114), (ST11
5) adding a call type J varied from 1 ≦ J ≦ L in step (S T11 7) in the call type J of arrival cell number VM (J) × I (J) to the SUM in (ST116) I do. Here, the step (ST117) is performed L times.

FIG. 19 shows the steps (ST112) of FIG.
4 is a flowchart of calculating the content of SUM, that is, the SUM occurrence probability PRB. In the figure, a step (ST118),
In (ST119) and (ST120), the call type J is changed to 1 ≦ J ≦ L.
, And in step (ST121), a combination CMB for selecting the ON (I) J calls among the N (J) set calls of the call type J is calculated, and in step (ST122), the call type J Of the N (J) set calls are turned on, and cumulatively integrated. Here, steps (ST121) and (ST122) are performed L times.

FIG. 20 shows the steps (ST121) of FIG.
ON of N (J) set calls of contents of call type J
It is a flowchart of the combination CMB calculation which selects the I (J) book which is a state. In the figure, _{N (J)} C _{I (J)} = N (J) ｛N
(J) -1} ・ {N (J) -2} ... {N (J) -I
(J) +1} / [I (J) • {I (J) -1} • {I
(J) -2｝ 1]. Step (S
T123), (ST124) and (ST125) pass through step (ST126) I (J) times and become M as a molecule.
The LTA is calculated in steps (ST123), (ST127),
By (ST128), step (ST129) is
(J) The MLTB to be used as the denominator is calculated, and the value of CMB is obtained in step (ST130).

FIG. 21 shows the steps (ST108) of FIG.
6 is a flowchart of calculating the contents of the cell, that is, the amount of cell traffic ρ. In the figure, a step (ST131),
In (ST132) and (ST133), the call type J is set to 1 ≦ J ≦ L
, And in step (ST134), the cell traffic amount N (J) × VM (J) × R of the call type J in question.
Ρ is calculated by cumulatively adding (J). Here, the step (ST134) is performed L times.

[0017]

In the conventional call admission control system, the step (S) is performed in the call admission judgment shown in FIG.
Each time the burst overflow rate BT of T3) is calculated, the multi-layered nested algorithm shown in FIGS. 16 to 21 must be executed, and the amount of calculation is enormous.
The calculation took a long time. In particular, the increase in the amount of calculation when the call type N (J) increases is remarkable. When the call type N (J) is 3 or more, the calculation becomes very difficult and is not practical. Also, even when the call type N (J) is small,
There is a problem in that real-time processing for making a call acceptance determination immediately upon calling is impossible.

The inventions of this has been made to solve the above problems, there is no need to perform complex call admission permission determination every time a call is generated, to obtain a simple call admission control scheme It is intended to be. It is another object of the present invention to obtain a simple call admission control method and to obtain a call admission control method with high network utilization efficiency in consideration of the effect of statistical multiplexing between call bundles.

In the call admission control system, when the number of call bundles and the call capacity of the target call type are configured to correspond one-to-one, the call type of interest near the transition point where the call bundle number changes. When the capacity of the call repeatedly changes, the setting / cancellation of the call bundle is repeated each time. Since a considerable amount of processing is required for setting and canceling the call bundle, if this processing is performed frequently, the processing amount increases, which causes a problem that the software and the hardware circuit scale increase.

Furthermore, even if the capacity of the call of the call type of interest repeatedly changes near the transition point where the number of call bundles changes, it is possible to obtain a method in which the call bundle is not repeatedly set and released each time. The purpose is. It is also intended to reduce the amount of processing due to the change in the number of calls, thereby reducing the amount of software and the scale of the hardware circuit.

[0021]

A call acceptance system according to the present invention.
Your system, put in an asynchronous transfer mode network, the net-user or et al.
Call reception system that determines whether there is room to accept calls
In the control method, a set number of calls are classified into call types.
When a new call is made, the new call is
If the new call is
If it does not fit, just set a new call
Determining means for determining whether the frequency has a margin, the determination
As a result of the judgment by the means, if there is room, a new call
And a new call bundle setting means for accepting the new call of the above with constant, above-size
If there is no room as a result of the judgment by the
Means for rejecting a call.
Features.

[0022] The admission control method may further comprise :
At the end of the call, there is a call bundle that becomes empty due to the end of the call
In such a case, there is provided a release means for releasing the hang-up of the call.
It is characterized by.

The above-mentioned call admission control method further comprises a call bundle setting.
The burst overflow rate as a criterion for determining the possibility of
It has a means for performing calculations and calculates the burst overflow rate.
The means for determining the occurrence of a new call and the release of the call are
And the cell traffic of the set call bundle when the new call bundle is set.
Add the increment of cell traffic volume of new call to the traffic volume
And, means for determining the cell traffic of the novel, preset call
New setting for the burst overflow rate of the bundle
Of the new cell traffic volume and the old
Burst overflow with weighted addition based on the ratio to the amount of traffic
Means for updating the rate, and when the
Of the cell traffic volume of the released call from the cell traffic volume of
Means to calculate the new amount of cell traffic by subtracting the decrement
And the ratio of the ending packet to the burst overflow rate of the preset packet.
The decrement of the overflow rate is determined by the new cell traffic
Weighted and added by the ratio of
And means for recurrently updates the strike overflow rate, the Kotaba
Calculate the change in burst overflow rate when setting and canceling
The number of cells arriving within a certain period
Is characterized by using a probability that the number is smaller than a certain number.

The new call bundle setting means forms a predetermined call type.
When the call capacity of the group of calls
With an increase means for the number of calls bundle group is increased by a predetermined amount, the solutions
The removing means reduces the capacity of the call in the call bundle group, and
Prescribed standard when the number of calls in a group of calls is increased by steps
When a different criterion is reached, the number of
And a reducing means.

The new call bundle setting means forms a predetermined call type.
When the call capacity of the group of calls
With an increase means for the number of calls bundle group is increased by a predetermined amount, the solutions
The removing means reduces the capacity of the call in the call bundle group, and
Prescribed standard when the number of calls in a group of calls is increased by steps
When a predetermined standard different from
A predetermined amount different from the predetermined amount when the number of calls in the group is increased
And means for reducing the number of calls in the group of calls.
And features.

[0026]

[Action] According to the inventions of this, introduced the concept of Kotaba summarizing a certain number of calls to the call type, there was a new call,
It is intended to calculate the burst overflow rate If you set the new call bundle can not pay its call to call a bunch of existing, call acceptance permission determination to calculate the burst overflow rate for each individual call Need to be performed.

Further , in the present invention, when the call is terminated.
If there is a call bundle that becomes empty due to the end of the call
Then, release the above call and calculate a new burst overflow rate.
You. Therefore, the burst overflow rate is calculated every time a call ends.
It does not do.

Further , in the present invention, since the burst overflow rate is used as a criterion for judging whether a call bundle can be set or not, the bandwidth can be efficiently used in consideration of the effect of statistical multiplexing between call bundles. In addition, since the burst overflow rate is updated by a recursive method when setting and canceling the call bundle, it is not necessary to calculate the burst overflow rate from the beginning by following a complicated algorithm each time the call bundle setting is determined. A new burst overflow rate can be obtained only by adding the weight of the change in the burst overflow rate of the newly set or released traffic to the burst overflow rate of the set traffic with the ratio of the old and new cell traffic volumes. it can. Further, in the present invention, the probability that the number of cells arriving within a certain period of time becomes a certain number or more is used as a parameter when calculating the change in the burst overflow rate for the newly set call or the released call. Therefore, it is possible to handle an arbitrary call that is not limited in speed or generation mode.

Further , the call admission control method according to the present invention provides a call capacity of a target call type when the number of call bundles is increased without making the call capacity of the target call type correspond to the call bundle number on a one-to-one basis. The call capacity of the call type of interest when the number of call bundles is reduced is set to a different value, and the relationship between the capacity of the call of the call type of interest and the number of call bundles is made to have a hysteresis, so that the call Even if the call volume of the call type of interest repeatedly changes small in the vicinity of the transition point where the number of bundles changes, the number of bundles is fixed and the setting and release of the bundle are not frequently repeated every time the change occurs.

Further, in the call admission control method according to the present invention, the number of calls when the capacity of the call of interest increases when the capacity of the call of interest does not correspond to the capacity of the call of interest in one-to-one correspondence. The amount of increase and the amount of decrease in the number of call bundles when the capacity of the call of the call type of interest decreases are set to different values, so that the relationship between the capacity of the call of the call type of interest and the number of call bundles has hysteresis. By doing,
Even if a small change in the call capacity of the call type of interest repeats a small change near the transition point where the number of calls changes, the number of calls is fixed, and the setting and release of the call are not frequently repeated every time the change occurs.

[0031]

[Embodiment 1] It will now be explained with reference to an embodiment of the inventions of this. FIG.
Is a diagram for explaining the concept of call bundle, in which 1 is a call,
2 indicates call volume. 2 (a) and 2 (b) are diagrams for explaining a call during a link and a call bundle, wherein 1a denotes a call type a.
, 1b is a call of call type b, 2a is a call bundle of call type a, 2b is a call bundle of call type b, and 3 is a link.

In FIGS. 1 and 2, six calls are combined into one call bundle for call type a, and three calls are combined into one call bundle for call type b. FIG. 2A shows an example of a call bundle group, in which there are two call bundles of a call type a and a call type b
Indicates a call bundle group set in the link.
Here, if a new call of call type a occurs, there is still room in the link, so that a new call bundle 2a can be set and a new call can be accepted as shown in FIG. it can.
Conversely, in the state of FIG. 2B, when one call of the call type a is completed, the call bundle in which no call is lost due to the termination of the call is released from the call bundle group.

The two-state ON / OFF model of FIG. 3 is the same as that of the conventional example. 4 (a) and 4 (b) are flowcharts of processing at the time of accepting a call. In FIG. 4 (a), in step (ST1), it is determined whether or not a new call fits into an existing call bundle. Step (ST2)
In step (ST3), if the call acceptance is permitted, and if the answer is not satisfied, the burst overflow rate BT when a new call bundle is set is calculated.

As a result, it is determined in step (ST4) whether or not the burst overflow rate BT is equal to or less than a specified value. If the burst overflow rate BT is equal to or less than the specified value, the process proceeds to step (ST).
In 5), a new call bundle is set, and in step (ST2), call acceptance is permitted. If the burst overflow rate is equal to or greater than the specified value, call acceptance is rejected in step (ST6).

FIG. 4 (b) is a flowchart of a process at the time of call disconnection. In step (ST7), it is determined whether or not there is an empty call bundle. If there is a call bundle, the process proceeds to step (ST8) to release one call bundle. In step (ST3b), the burst overflow rate BT when the call bundle is released is calculated.

Embodiment 2 FIG. In the above embodiment, whether or not the value of the burst overflow rate is equal to or less than the reference value is used to determine whether or not a new call can be set. However, this need not be the case, and other determination criteria may be used. .

Embodiment 3 FIG. Next, another embodiment will be described with reference to the drawings. The third embodiment specifically describes how to calculate the burst overflow rate in the step (ST3) of FIG. 4A and the step (ST3b) of FIG. 4B. The step (ST3) of FIG. 4A also corresponds to the step (ST3) of FIG.
b) also calls the same BT update flowchart shown in FIGS.

FIG. 5 and FIG. 6 are flowcharts of the burst overflow rate BT, which is the center of the present invention. FIG.
9 is a flowchart of BT initialization. Since the method of the present invention employs a recursive method, it is necessary to set an initial value, but this need only be set once at the beginning. First, the parameters used will be described. Here, parameters represented by the same symbols as in the related art have the same meaning. In this case, the ratio between the ON state 12 and the ON state 12 plus the OFF state 13 in FIG. 3, that is, T1 (J) / T2 (J) is defined as R (J). J represents a call type.

In this embodiment, in order to represent the cell arrival interval TM (J) in the ON state of FIG.
And the speed coefficient A (J). Rate coefficient A of call type J
(J) is defined as A (J) = T / TM (J). That is,
A (J) is the cell arrival speed 1 in the ON state 12 of FIG.
/ TM (J) is a coefficient indicating how many times the reference speed 1 / T is, and the cell arrival speed in the ON state is high.
A (J) increases as (J) decreases. BT is the burst overflow rate, ρ is the amount of cell traffic, ρ _n is the updated value of the amount of cell traffic, and M (J) is the number of calls in one call bundle of call type J.

In the algorithm of the present embodiment, ρ and ρ _n are distinguished because both the value before updating and the value after updating are used for the amount of cell traffic. G indicates a call type of a call to be generated or terminated. G is an element of a set of call types J. S (H)
Is the probability that the number of cells arriving at the reference interval T will be H or more,
S _N (H) indicates the updated value of S (H). As for S (H), both the value before the update and the value after the update are used.
(H) and S _N (H). HMAX indicates the theoretical maximum value of H, and HM indicates the maximum value set for the convenience of H processing.

Next, a method of updating the burst overflow rate BT shown in FIGS. 5 and 6 will be described. First, step (ST15)
Selects whether the update is due to the occurrence of a call or the termination. If it is due to the occurrence of a call, the cell traffic amount ρ is updated in step (ST16). That is, the cell traffic volume of the set call is stored in ρ, and the increase M (G) × A (G) × R (G) / T of the cell traffic volume due to the newly generated call bundle of the call type G is stored in ρ. In addition, a new ρ _n is obtained. In the expression, ρ ← ρ _n , ρ _n ← ρ + M
(G) × A (G) × R (G) / T.

Next, in step (ST17), the burst overflow rate BT of the set call and the increment of the burst overflow rate due to the newly generated call bundle are determined.

[0043]

(Equation 2)

Are weighted by the ratio of the new and old cell traffic amounts ρ / ρ _N and added to update the value of the burst overflow rate BT. In the formula

[0045]

(Equation 3)

Is as follows. Finally, in step (ST18), the probability S (H) that the number of cells arriving within the period T becomes H or more.
To update.

This updating formula is

[0048]

(Equation 4)

Is as follows. However, S (H) is defined only when H is positive, and S (H) = 1 when H is negative. In addition, since H cannot be infinitely increased in the calculation process, if H exceeds the upper limit value HM in the process, S
(H) = 0.

If it is determined in step (ST15) that the update is due to the termination of the call, the process proceeds to step (ST1).
9), the cell traffic amount ρ, the burst overflow rate BT in step (ST20), and the period T in step (ST21).
The probability S (H) that the number of cells arriving within is equal to or more than H is
Updating is performed as shown in FIG. As described above, in this embodiment, the cell traffic amount ρ, the burst overflow rate BT, and the probability S (H) that the number of cells arriving within the period T becomes H or more are recursively updated. Need to set each initial value.

FIG. 7 shows the initial values. Step (ST
To indicate Suyo to 22), the initial value of the cell traffic [rho _N
= Ρ = 0, initial value of burst overflow rate is BT = 0, period T
S (H) = 0 is set as the initial value of the probability S (H) that the number of cells arriving within is H or more. The initial value of S (H) is H
Are set in the range of 0 ≦ H ≦ HM that can be taken by The order of setting these initial values is arbitrary.

The method of the call admission control in this embodiment is summarized above. First, before starting the call admission control, an initial value is set based on FIG. Next, when there is a call application from the user, a call acceptance determination is made according to FIG.

First, in step (ST1), it is determined whether or not the new call can be accommodated in the current call bundle. If the new call can be accommodated, call acceptance is permitted in step (ST2). If not, a new call is newly accepted in step (ST3). BT when setting call ringing
Is updated by the procedure shown in FIGS. 5 and 6, and the step (ST
Proceeding to 4), it is determined whether or not the BT is equal to or less than a specified value. If the BT is equal to or less than the specified value, the process proceeds to step (ST5) to set a new call bundle, and permits call acceptance in step (ST2).
If BT is equal to or greater than the specified value, call acceptance is rejected in step (ST6). When disconnecting the set call, it is determined in step (ST7) of FIG. 5 whether or not there is an empty call bundle.
Proceeding to 8), one call is released and the BT is updated in step (ST3b) according to the procedure shown in FIG.

In the conventional example, the calculation of the burst overflow rate BT which had to follow the flow chart of the multiple nested structure from FIG. 16 to FIG. 21 is performed only in the procedure shown in FIG. 5 and FIG. You can.

Embodiment 4 FIG. In the above embodiment, all the procedures are shown by flowcharts using software, but a part or all of them may be realized by hardware.

Embodiment 5 FIG. Further, in the above embodiment, the rate coefficient A (J) and the ON state ratio R (J) are used as parameters representing the nature of the call, but the cell arrival rate 1 / TM (J) or the average cell rate in the ON state. Other parameters derived from FIG. 3 such as the arrival speed A (J) · R (J) / T may be used.

Embodiment 6 FIG. Further, in the above embodiment, the parameter H is changed in the range of 0 ≦ H ≦ HM limited by the upper limit value HM in processing.
As shown in steps (ST23) and (ST26) of FIG. 8, the value of the theoretical maximum value HMAX of H is calculated, and the values of steps (ST18) and (ST18) of FIG.
If the update of S (H) in 21) is performed in the range of 0 ≦ H ≦ HMAX (step (ST18) and step (ST2 in FIG. 8)
1)), the calculation time can be further reduced.

Embodiment 7 FIG. Steps (ST24) and (ST25) in FIG.
An overflow process for the value of H as shown in FIG.

Embodiment 8 FIG. Hereinafter, another embodiment will be described with reference to the drawings. FIG. 9 is a diagram showing a call admission control method according to one embodiment of the present invention. (A) of the figure shows an algorithm at the time of calling, and (b) shows an algorithm at the time of call termination. FIG. 10 is a diagram showing the relationship between the call capacity of the call type of interest and the number of call bundles in the embodiment. The horizontal axis of the figure shows the call capacity of the call type of interest and the vertical axis shows the number of call bundles. In the figure, 10
1 is a graph showing the relationship between the call capacity of the call type of interest and the number of call bundles,
102a to 102e indicate paths when the number of calls changes from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, respectively, and 103a to 103e indicate the numbers of calls from 2 to 1, 3 respectively. It represents a route when transitioning from 2, 4 to 3, 5 to 4. In the figure, 102a to 102e
That the upper end of the call is a hollow circle and the lower end is a black circle means that when the value of the call capacity of the call type of interest increases, 102a to 102
When it is above any of e, it indicates that the number of calls has a value indicated by a black circle at the lower end. 103a to 103
That the upper end of e is a black circle and the lower end is a hollow white circle means that the value of the call capacity of the call type of interest decreases from 103a to 103a.
When it is above any of 3e, it indicates that the number of calls has a value indicated by a black circle at the upper end.

Next, the algorithm of this embodiment will be described. In FIG. 9A, when a new call is made, it is determined in ST1 whether the currently set call bundle has room to accommodate the new call. S
Proceeding to T2, the acceptance of the new call arriving is permitted. If there is no room, the process proceeds to ST3. In ST3, the burst overflow rate BT when a new call is set is calculated. As a result, it is determined in ST4 whether the burst overflow rate BT is equal to or less than a specified value. If it is determined in ST4 that the burst overflow rate BT is equal to or less than the specified value, the process proceeds to ST5, where a new call bundle is set, and in ST2, call acceptance is permitted. If it is determined in ST4 that the burst overflow rate BT is equal to or greater than the specified value, ST
Proceed to 6 and call acceptance is rejected. This embodiment is the same as the case of FIG. 4 regarding the call connection processing.

In FIG. 9B, in ST7, it is determined whether or not there is a call bundle that has become empty due to the termination of the call. Here, if there is no empty call bundle, it is left as it is, and if there is an empty call bundle, the process proceeds to ST7b. If it is determined in ST7 that there is an empty call stack, the empty call stack can be released. However, the process proceeds to ST7b without immediately canceling the empty call stack, and the call stack is released. When one is released, it is determined whether or not the safety margin SM is left. If the safety margin SM remains even after releasing one call, ST8
To release one call. If the safety margin SM does not remain after one call is released, the call is not released and is left as it is. After releasing one call in ST8, ST
In step 3b, the burst overflow rate when the call release is released is calculated, and the call disconnection process ends.

When the number of call bundles and the capacity of the call of the target call type correspond one-to-one, even if the capacity of the call of the target call type increases or decreases, the capacity of the call of the specific target call type is determined. The number of call bundles corresponding to is one, whereas FIG.
Graph 10 showing the relationship between the call capacity and the number of call bundles of the call type of interest.
In No. 1, it can be seen that the route is different when the call capacity of the call type of interest increases and decreases. For example, the call capacity of the call type of interest increases from zero and CC1-p (p ≦ S
When M) is reached, the number of calls is one. Then, when the call capacity of the call type of interest increases and reaches CC1, the number of call bundles increases by one to two. When the capacity of the call of the call type of interest further increases to CC1 + p, the number of call bundles is still two. Here, even if the call capacity of the call type of interest decreases to CC1-p, the number of call bundles remains two. Also, even if the call capacity of the call type of interest changes between CC1 + SM and CC1-p, the number of call bundles is fixed at 2 and 1 and 2
Does not transition frequently.

Embodiment 9 FIG. Further, in the above embodiment, the boundary point at the time of the transition of the number of call bundles is shown in FIG.
0 has been described, but 10 in FIG.
The combination of black circles and white circles above and below 2a to 102e and 103a to 103e is not limited to this, and other combinations may be used. Valid combinations are 4 including the example in FIG.
FIG. 11 shows another example. FIG.
1 is a diagram showing the relationship between the call capacity of the call type of interest and the number of call bundles, and the horizontal axis of the figure shows the call capacity of the call type of interest and the vertical axis shows the number of call bundles as in FIG. In the figure, reference numeral 111 denotes a graph representing the relationship between the call capacity of the call type of interest and the number of calls,
2e represents a path when the call bundle number changes from 1 to 2, 2 to 3, 3 to 4, 4 to 5, 11
Reference numerals 3a to 113e represent paths when the number of calls changes from 2 to 1, 3 to 2, 4 to 3, and 5 to 4, respectively. In the figure, the upper end of 112a to 112e is a white circle with a hollow center and the lower end is a black circle. This means that when the value of the capacity of the call of the call type of interest is increased, when the call is over any of 112a to 112e, The number indicates that it takes a value indicated by a black circle at the lower end. Further, the fact that the upper ends of 113a to 113e are hollow white circles and the lower ends are black circles means that when the capacity of the call of the call type of interest decreases, the number of call bundles is lower than any of 113a to 113e. Take the values indicated by black circles.

Embodiment 10 FIG. FIG. 12 shows an embodiment in which the safety margin SM of FIG. 9 shown in the eighth embodiment is made equal to the maximum number of calls in a call bundle. In this way, the safety margin SM may be equal to the maximum number of calls that can be handled.

Embodiment 11 FIG. In the above eighth, ninth, and tenth embodiments, the case where the increase and decrease in the number of call bundles of the call bundle group is performed in units of one call bundle has been described. However, the number of call bundles that increase and decrease need not be constant. You can change it. For example, the number of call bundles may be set to 4 from the beginning, and when the number is increased next, the increment may be changed from 4 to 4 + 2 and further to 4 + 2 + 1. Alternatively, the range of increase / decrease may be appropriately changed depending on the use time zone or the past use situation.

Embodiment 12 FIG. Next, another embodiment of the invention will be described. In the above eighth, ninth, and tenth embodiments, the case where the increase width and the decrease width of the number of call bundles are the same is shown, but the increase width and the decrease width may be changed.
For example, consider the case where the increase width is 1 and the decrease width is 2. In FIG. 13, when the call capacity increases as before and continues to 5, the call capacity decreases and the number of call bundles decreases by 1 when the call capacity decreases to CC4, as in this embodiment. Assuming that the reduction width is 2, the number of call bundles is not reduced until a margin of 2 is made. Therefore, the number of call bundles will decrease from 5 to 3 when the call capacity falls below CC3.

Therefore, the call capacity is changed from CC3 to CC5.
And the call capacity increases from CC5 to C5.
The path of decrease when C3 is reduced is different, and the relationship between the two can have hysteresis as shown in Examples 8, 9, and 10. In other words, the call capacities when increasing the number of call bundles are CC1, CC2, CC
The call capacity when reducing the number of call bundles is CC
1, CC3, CC5, ..., CC2, CC4, C
In C6,..., There is a larger number of calls, that is, a capacity of 3, 5, and 7, and CC2, CC4, CC6,
.. Will not frequently increase or decrease the call capacity, and will have the same effect as the present invention.

Embodiment 13 FIG. Next, another embodiment of the invention described in the twelfth embodiment will be described. FIG. 14 shows an embodiment in which the safety margin SM is increased. In the tenth embodiment, the case where the width SM of the safety margin is equal to the maximum number of calls in the call bundle is shown, but the width SM of the safety margin may be larger than the maximum number of calls in the call bundle. However, when the width SM of the safety margin is larger than the maximum number of calls in the call bundle, it is preferable to make the decrease width larger than the maximum number of calls in the call bundle from the viewpoint of the line use efficiency. In this example, the increase width is set to 1 and the decrease width is set to 2.

As described above, the call admission control method according to the present invention is a call admission control method using a call bundle in an asynchronous transfer method network, that is, whether the asynchronous transfer method network has room to accept a call from a user. Call admission control method to determine whether
A set of a fixed number of calls in a call type is used as a call bundle. When a new call is generated, if the new call falls within the existing call bundle, the call is accepted immediately, and if not, a new call bundle is set. Judgment as to whether or not there is a margin in the band as much as possible, if there is a margin, set a new call bundle and accept the above new call, if there is not enough, reject the acceptance of the above new call, Also, at the end of a call, if there is a call bundle that becomes empty due to the end of the call, the call bundle is released. In a call admission control system, a new call falls into an existing call bundle when a call is made. The number of calls and the call capacity of the call type of interest when judging whether or not the call bundle can be released at the end of the call.
The without one-to-one correspondence, in number of calls flux corresponding to the capacity of the same attention call type calls, and the number of calls bundle when ie during call capacity of the target call type call increases, interest call type When the call capacity decreases, that is, when the number of call bundles at the end of a call is set to a different value, even if there is a call bundle that becomes empty due to the end of the call, it is not immediately released, and the call capacity and call capacity of the target call type are not released. It is characterized in that the relationship between the number of bundles and the number of bundles has hysteresis.

In the above embodiment, the case of increasing and decreasing the number of call bundles has been described. However, the case of increasing and decreasing the number of call bundles at a predetermined rate with respect to the number of already used call bundles may be used. . For example, the number of calls may be increased or decreased by the number of calls that is 20% (rounded down to the decimal point) of the current number of calls.

[0071]

As in the above, according to the present invention, according to the inventions of this, and call bundles are collectively call a certain number to call type, it was to perform the update of the criteria parameters of the call acceptance capability determination for each Kotaba So
This makes it very easy to determine whether to accept a call when a call is generated, and significantly reduces the time required to control call acceptance.

[0072] Also, using a burst overflow rate setting propriety determination call bundles of this, since the further to the burst overflow rate to be easily calculated by recurrence techniques, the statistical multiplexing effect between call bundle There is an effect that call admission control can be performed at a high speed while taking into account.

[0073] In addition, the capacity and Kotaba number of attention call type of call without a one-to-one correspondence, reduction and capacity of attention call type of a call at the time to increase the number of calls bundles, the number of calls bunch Since the call capacity of the call type of interest at the time of the call is set to a different value and the relationship between the call capacity of the call type of interest and the number of call bundles is made to have a hysteresis, near the transition point where the number of call bundles changes Therefore, even if the call capacity of the call type of interest repeatedly changes, the number of calls changes each time,
Cancellation is not repeated frequently, thereby reducing the amount of processing involved in setting and canceling the call stack, and thereby reducing the amount of software and the scale of the hardware circuit.

[0074] In addition, the capacity and Kotaba number of attention call type of call without a one-to-one correspondence, also in the number of calls flux corresponding to the capacity of the same attention call type of a call, the attention call type of call When the capacity increases, that is, the number of calls when a new call arrives, and when the capacity of the call of the call type of interest decreases, that is, when the number of calls when the call leaves, the call capacity and the call capacity of the call type of interest are different. Since the relationship between the number of calls and the number of calls is made to have a hysteresis, even if the call capacity of the call type of interest repeatedly changes near the transition point where the number of calls changes, the number of calls changes every time. This eliminates the need to repeatedly set and release call bundles, thereby reducing the amount of processing involved in setting and releasing call bundles, thereby reducing the amount of software and the hardware circuit scale. There is.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the concept of a call and a call bundle.

FIG. 2 is a diagram illustrating a call and a call bundle during a link.

FIG. 3 is a diagram showing a two-state ON / OFF model representing burst traffic in an ATM network.

FIG. 4 is a flowchart of processing at the time of accepting a call according to an embodiment of the present invention and at the time of disconnecting a call according to the embodiment;

FIG. 5 is a flowchart of updating a burst overflow rate BT according to another embodiment.

FIG. 6 is a flowchart of updating a burst overflow rate BT according to another embodiment.

FIG. 7 is a flowchart of the burst overflow rate BT initial setting of the embodiment.

FIG. 8 is a flowchart of another embodiment of the present invention.

FIG. 9 is a flowchart illustrating an algorithm of a call admission control method according to another embodiment.

FIG. 10 is a diagram showing a relationship between the number of call bundles and the capacity of a call of a target call type in the call admission control method according to the embodiment.

FIG. 11 is a flowchart illustrating an algorithm of a call admission control method according to another embodiment of the present invention.

FIG. 12 is a diagram showing the relationship between the number of call bundles and the call capacity of a call type of interest in a call admission control system according to another embodiment of the present invention.

FIG. 13 is a diagram showing the relationship between the number of call bundles and the call capacity of the call type of interest in the call admission control method according to one embodiment of the present invention.

FIG. 14 is a diagram showing the relationship between the number of call bundles and the call capacity of a call type of interest in a call admission control system according to another embodiment of the present invention.

FIG. 15 is a flowchart of a conventional call acceptance determination.

FIG. 16 is a flowchart of a conventional calculation of a burst overflow rate BT.

FIG. 17 shows an expected value E of a burst overflow rate in a conventional example.
It is a flowchart figure of PT calculation and accumulation addition subroutine.

FIG. 18 is a flowchart of a total SUM calculation subroutine of the number of arrival cells in a conventional example.

FIG. 19 is a flowchart of an occurrence probability PRB calculation subroutine in a conventional example.

FIG. 20 is a flowchart of a combination calculation subroutine for taking I (J) from N (J) in a conventional example.

FIG. 21 is a flowchart of a cell traffic amount ρ calculation subroutine in a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Call 1a Call of call type a 1b Call of call type b 2 Call bundle 2a Call bundle of call type a 2b Call bundle of call type b 3 Link ST1 Judgment as to whether or not the new call falls within the existing call bundle ST2 Call acceptance permission ST3 Calculation of burst overflow rate BT ST3b Calculation of burst overflow rate BT ST4 Judgment whether BT is below standard value ST5 Setting of new call bundle ST6 Call rejection ST7 Whether there is an empty call bundle during call disconnection processing ST7b When one call bundle is released, it is determined whether or not there is a safety margin SM. ST8 Release of the call bundle ST16 Update of the cell traffic volume ρ at the time of call bundle setting ST17 Burst overflow rate BT at the time of call bundle setting Update ST18 The number of cells arriving within the period T when the call bundle is set is H
Update of the probability S (H) of more than the number ST19 Update of the cell traffic amount ρ at the time of call release ST20 Update of the burst overflow rate BT at the time of call release ST21 Number of cells arriving within the period T at the time of call release H
Update of the probability S (H) of the number of calls or more 101 A graph representing the relationship between the call capacity of the target call type and the number of call bundles, 1102a to 102e The number of call bundles is 1 to 2, 2 to 3, 3 to 4, 103a to 103e representing the path when transitioning from 4 to 5 103a to 103e representing the path when the call number transitions from 2 to 1, 3 to 2, 4 to 3, and 5 to 4 respectively

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-172733 (JP, A) JP-A-4-58641 (JP, A) JP-A-2-84844 (JP, A) JP-A-4- 150438 (JP, A) JP-A-5-68046 (JP, A) Proceedings of the IEICE Spring Conference, SB-5-3 (1991-3-15), Haruko Kato et al. Proposal of an admission control method, p. 3-395 (58) Field surveyed (Int. Cl. ⁶ , DB name) H04L 12/28 H04L 12/56

Claims (5)

(57) [Claims] 1. An asynchronous transfer method network, wherein said network is a user.
Calls to determine if there is room to accept calls from
In the attached control system, a set of calls with a fixed number of calls
If a new call falls into the current call bundle at the time of the call
And a new call set-up if the new call does not fit in the current call set-up.
Judgment means to judge whether there is enough bandwidth for
When the result of determination by said determining means, if there is a margin new
New call bundle setting means for setting a call bundle and receiving the above new call
If the result of the judgment by the above judgment means indicates that there is no room,
A call rejection means for rejecting the acceptance of the new call . 2. The admission control system according to claim 1 , further comprising:
At the end of the call, there is a call bundle that is empty due to the end of the call
If there is a
2. The call admission control system according to claim 1, wherein: 3. The call admission control method according to claim 1 , further comprising:
Burst overflow rate as a criterion for determining the possibility of setting and cancellation
Means for calculating the burst overflow rate, wherein the means for calculating the burst overflow rate comprises:
Means for determining occurrence and release of call bundle , and, when setting up the new call bundle, cell traffic of the preset call bundle
Volume plus the increment of the cell traffic volume of the new call
Means for determining the amount of cell traffic of a new call bundle and the ratio of the newly set call bundle to the burst overflow rate of the preset call bundle.
And the new cell traffic obtained above
Weighted and added according to the ratio of
Means for updating the strike overflow rate, and when releasing the above call bundle, whether the cell traffic volume of the preset call bundle
Subtract the decrement of the cell traffic volume of the released call from the
Means for determining the amount of cell traffic, and the berth of the end packet relative to the burst overflow rate of the preset packet.
And the amount of new cell traffic calculated above
And weighted addition based on the ratio of the old cell traffic volume and the burst
Means for recursively updating the overflow rate, and changing the burst overflow rate at the time of newly setting and releasing the above-mentioned call bundle.
Arrive within a certain period as a parameter to calculate
Feature that the probability that the number of cells
3. The call admission control method according to claim 2, wherein 4. The new call bundle setting means forms a predetermined call type.
When the call capacity of the formed bundle reaches a predetermined standard,
An increasing means for increasing the number of calls in the bundle by a predetermined amount , wherein the canceling means reduces the capacity of calls in the bundle and reduces
Predetermined when the number of call bundles in the call bundle group is increased by increasing means
When a criterion different from the criterion is reached,
Claims characterized by comprising reducing means for reducing
2. The call admission control method described in 2. 5. The new call bundle setting means forms a predetermined call type.
When the call capacity of the formed bundle reaches a predetermined standard,
An increasing means for increasing the number of calls in the bundle by a predetermined amount , wherein the canceling means reduces the capacity of calls in the bundle and reduces
Predetermined when the number of call bundles in the call bundle group is increased by increasing means
When a predetermined standard different from the standard is reached,
Is different from the predetermined amount when the number of calls in the group is increased
Reducing means for reducing the number of calls in the group of calls by a predetermined amount.
3. The call admission control method according to claim 2, wherein: