JPH053488A - Call admission control method - Google Patents

Abstract

(57) [Abstract] [Object] The present invention is characterized in that it is possible to perform simple call admission control without having to make a call admission decision based on complicated calculation every time a call occurs. To do. [Structure] It is judged whether or not the new call fits into the existing call bundle (ST1), and if it fits, the call acceptance is permitted (ST1).
2) If not, the burst overflow rate BT when a new call bundle is set is calculated (ST3). As a result, it is determined whether or not the burst overflow rate BT is less than or equal to a specified value (ST
4). Here, only when the burst overflow rate BT is equal to or less than the specified value, a new call bundle is set (ST5), and call acceptance is permitted (ST2). When the call is disconnected, it is determined whether or not there is an empty call bundle (ST7), and if there is an empty call bundle, the step (S).
In step T8, one call bundle is released (ST8), and the burst overflow rate BT when the call bundle is released is calculated (ST3).
b).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to ATM (Asynch)
The present invention relates to a call admission control method that performs control to determine whether or not a call originated by a user can be accepted by a Ronus Transfer Mode network based on information declared by the user, and to determine whether or not to accept the call. It is a thing.

[0002]

2. Description of the Related Art In a broadband ISDN network, a conventional synchronous transfer method (STM; Synchronous Tra) is used.
Asynchronous transfer method (AT) different from nsfer mode
M; Asynchronous Transfer M
digital signal transmission has been performed using the
Standardization is progressing in CITT (International Telegraph and Telephone Advisory Committee). In an ATM network, multimedia information having different properties such as voice, data, and images is multiplexed and transmitted at high speed. Therefore, call admission control, that is, whether or not the network can accept a call originated by the user is determined. It is necessary to make a judgment based on the information declared by the company and decide whether to accept the call.

FIG. 3 is a two-state ON / OFF model showing burst traffic in an ATM network subjected to the above control. In the figure, 11 is an ATM cell, 12 is an ATM cell
An ON state section in which cells occur at TM (J) intervals, 13
Is an OFF state section in which no cell is generated. In the 2-state ON / OFF model, cells are generated at TM (J) intervals only in the ON state section 12 of the T1 (J) time, and are not generated in the OFF state section 13. O
It is assumed that the N state 12 and the OFF state 13 are repeated in the cycle T2 (J).

The user makes the call he or she originates as shown in FIG.
The parameters T1 (J), T2 (J), TM (J) when modeled in the state ON / OFF model are directly or indirectly declared. The ATM network uses 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.

FIG. 15 is a call acceptance judgment for determining whether or not to accept a call by judging whether or not the network has room to accept a call originated by 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, the burst overflow rate BT is calculated based on the parameters declared by the user in step (ST3). In step (ST4), it is determined whether or not the burst overflow rate BT is less than or equal to a specified value. If BT is less than or equal to the specified value, no overflow occurs even if the call is accepted, so call admission is permitted (step (ST2) ), If BT has a positive value, the call acceptance is rejected because overflow occurs when the call is accepted (step (ST6)).

That is, the decision of refusal of call acceptance is made based on whether or not the value of the burst overflow rate BT is less than a specified value. The conventional method of calculating the burst overflow rate is described in, for example, IEICE Technical Research Report IN89-7 “A Study on Burst Traffic Queue Length Distribution” (Sato, Tanabe, Suzuki), which is shown in FIG. It is shown in the flow chart of FIG.

First, the parameters used in these flowcharts will be described. J represents a call type (call type). Since there are L calling types in all, J takes an integer value of 1 ≦ J ≦ L. The number of calls of the call type J is N (J), and of these, the number of calls in the ON state 12 in FIG. 3 is I (J). Ratio of ON state 12 in FIG. 3, that is, T1 (J) / T2 (J)
Let be R (J). Also, 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 above burst overflow rate,
ρ is the amount of cell traffic.

FIG. 16 is a flowchart of the conventional burst overflow rate BT calculation, which is the content of the step (ST3) of FIG. Step (ST101), (ST10
2) In (ST103), the value of the call type J is changed within the range of 1 ≦ J ≦ L, and steps (ST104) and (ST10).
5) and (ST106) for one call type J, 2 in FIG.
The number of calls I (J) in the ON state of 0 ≦ I (J) ≦ N
The number of changes is N (L) +1 in the range of (J), and in each case, the expected value EPT of burst overflow is calculated in step (ST107) and cumulatively added.

Here, the step (ST107) is

[0010]

[Equation 1]

It will be passed around. After this, step (S
In T108), the cell traffic amount ρ is calculated, and the expected burst overflow value EPT cumulatively added in step (ST109) is divided by the cell traffic amount ρ to obtain the burst overflow rate BT = EPT / ρ.

FIG. 17 shows the step of FIG. 16 (ST107).
6 is a flowchart of calculation and cumulative addition of the expected value EPT of the contents, that is, burst overflow. First step (ST
In 110), the total SUM of the number of arriving cells is calculated. Next, in step (ST111), it is determined whether or not SUM overflows 1, that is, whether or not burst overflow occurs, and SUM ≦
When the burst overflow does not occur at 1, the EPT value is not changed. When the burst overflow occurs at SUM> 1, at step (ST112), the occurrence probability PR of the SUM concerned is generated.
B is calculated, and in the step (ST113), the overflow SUM-
The product of 1 and the occurrence probability PRB, that is, the increment of the expected value of burst overflow, is added to the current expected value EPT of burst overflow to update the expected value EPT of burst overflow.

FIG. 18 shows the step of FIG. 17 (ST110).
3 is a flowchart of the calculation of the total SUM of the contents, that is, the number of arrival cells. Steps (ST114), (ST11
5) In (ST116), the call type J is changed within the range of 1 ≦ J ≦ L, and the number of arrival cells VM (J) × I (J) of the call type J is added to SUM in step (ST17).
Here, step (ST117) passes L times.

FIG. 19 shows the step of FIG. 17 (ST112).
2 is a flowchart of the calculation of the contents PRB, that is, the SUM occurrence probability PRB. In the figure, step (ST118),
In (ST119) and (ST120), the call type J is 1 ≦ J ≦ L
In step ST121, the combination CMB that selects the I (J) lines that are in the ON state among the N (J) set calls of the call type J is calculated in step (ST121), and the call type J is selected in step (ST122). The probability that I (J) of the N (J) set calls will be in the ON state is calculated and accumulated. Here, steps (ST121) and (ST122) are passed L times.

FIG. 20 shows the step of FIG. 19 (ST121).
ON among the setting calls of N (J) books of the contents of the 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) CI (J) = N (J)
・ {N (J) -1} ・ {N (J) -2} ... {N
(J) -I (J) +1} / I (J) · {I (J) -1}
-{I (J) -2} ... 1 is calculated. In steps (ST123), (ST124), and (ST125), MLTA that passes through step (ST126) I (J) times to become a molecule is converted into steps (ST123) and (ST12).
7) and (ST128), the step (ST129) is passed through I (J) times to calculate the MLTB that is the denominator, and the value of CMB is obtained in the step (ST130).

FIG. 21 shows the step of FIG. 16 (ST108).
3 is a flowchart of the calculation of the contents of cell traffic, that is, the amount of cell traffic ρ. In the figure, step (ST131),
The call type J is 1 ≦ J ≦ L in (ST132) and (ST133).
, And the cell traffic amount N (J) × VM (J) × R of the call type J in step (ST134).
(J) is cumulatively added to calculate ρ. Here, step (ST134) passes L times.

[0017]

In the conventional call admission control system, in the call admission judgment shown in FIG.
Each time the burst overflow rate BT of (T3) is calculated, it is necessary to execute the multi-nested algorithm shown in FIGS. 16 to 21, and the amount of calculation is enormous.
The calculation took a long time. In particular, when the call type N (J) is increased, the calculation amount is remarkably increased, and when the call type N (J) is 3 or more, the calculation becomes very difficult and not practical. Even if the call type N (J) is small,
There is a problem in that it is impossible to perform a real-time process for making a call acceptance judgment immediately when a call is made.

The first aspect of the present invention has been made to solve the above problems, and provides a simple call admission control system that does not require a complicated call admission decision every time a call occurs. The purpose is to get. This second invention is also made to solve the above problems,
An object of the first invention is to achieve a simple call admission control method, and to obtain a call admission control method with high network utilization efficiency in consideration of the statistical multiplexing effect between call bundles. There is.

Further, in the conventional call admission control system, the number of call bundles and the call capacity of the call type of interest have a one-to-one correspondence, so attention is paid near the transition point where the number of call bundles changes. When the call capacity of the call type changes repeatedly, the call bundle is set / released each time. Since a considerable amount of processing is required to set / cancel the call bundle, if this is frequently performed, the processing amount increases, which causes an increase in software and an increase in hardware circuit scale.

The third and fourth inventions have been made in order to solve the above problems, and even if the call capacity of the target call type repeatedly changes near the transition point where the number of call bundles changes. The purpose is to obtain a method that does not frequently repeat setting and releasing call bundles each time. Moreover, the purpose is to reduce the processing amount according to the change of the number of call bundles, and eventually to reduce the software amount and the hardware circuit scale.

[0021]

The call admission control system according to the first aspect of the present invention is a call admission control that is placed in an asynchronous transfer system network and determines whether or not the network has room to accept a call from a user. In the control method, we introduced the concept of a call bundle that collects a certain number of calls for each call type.When a new call occurs, if the new call fits in the current call bundle, the call is accepted immediately, and if it does not subside. It is judged whether or not there is a margin of bandwidth for newly setting a call bundle. If there is a margin, a new call bundle is set and the above new call is accepted. It rejects the acceptance of a new call, and at the end of the call, if there is a call bundle that becomes empty due to the end of the call, the call bundle is released.

The call admission control system according to the second invention is
In the call admission control system of the first aspect of the present invention, in the calculation of the burst overflow rate, which is a criterion for determining the possibility of setting or releasing the call bundle, it is determined whether a new call bundle is generated or the call bundle is released. Means, a means for adding the increment of the cell traffic volume of the new call bundle to the cell traffic volume of the already set call bundle when setting the new call bundle, and obtaining the new cell traffic volume, and the burst overflow rate of the preset call bundle. And means for updating the burst overflow rate by weighting and adding the increment of the burst overflow rate of the newly set call bundle with the ratio of the new cell traffic amount and the old cell traffic amount obtained above, and the already set at the time of releasing the call bundle. A means for adding a decrement of the cell traffic volume of the released call bundle to the cell traffic volume of the call bundle to obtain a new cell traffic volume, and a reduction of the burst overflow rate of the preset call bundle and the burst overflow rate of the terminated call bundle. A means for gradually updating the burst overflow rate by weighted addition with the ratio of the obtained new cell traffic amount and the old cell traffic amount, and the burst overflow rate at the time of newly setting or releasing the call bundle. The probability of the number of cells arriving within a certain period being equal to or less than a certain number is used as a parameter for calculating the change amount of.

In the call admission control system according to the third aspect of the present invention, when it is determined whether or not a new call fits in the current call bundle at the time of calling,
In addition, when deciding whether or not the call bundle can be released at the end of the call, the call of interest when increasing the number of call bundles without making one-to-one correspondence between the number of call bundles and the call capacity of the call type of interest The call capacity of the target call when reducing the call capacity of the seed and the number of call bundles are set to different values, and even if there is a call bundle that becomes empty when the call ends, it is not immediately released and There is a hysteresis in the relationship between the call capacity and the number of call bundles.

In the call admission control system according to the fourth invention, the call admission control system according to the third invention has different call capacities in the call bundle group when the number of call bundles increases and when the number of call bundles decreases. On the other hand,
The amount of increase in the number of call bundles when increasing and the amount of decrease in the number of call bundles when decreasing are different so that there is hysteresis in the relationship between the call capacity in the call bundle group and the number of call bundles in the call bundle group. It was done like this.

[0025]

According to the first aspect of the present invention, the concept of a call bundle in which a certain number of calls are collected according to the call type is introduced, and a new call is made. However, the call is put into the existing call bundle. The burst overflow rate is calculated only when a new call bundle is set and when the call bundle is released, and it is necessary to calculate the burst overflow rate for each call and judge whether to accept the call. Disappears.

In the second aspect of the invention, since the burst overflow rate is used as a criterion for determining whether or not a call bundle can be set, the band can be efficiently used in consideration of the statistical multiplexing effect between call bundles. Also, since this burst overflow rate is updated by a recursive method at the time of setting and releasing a call bundle, it is not necessary to follow a complicated algorithm every time the call bundle is set or not to calculate the burst overflow rate from the beginning. A new burst overflow rate can be obtained only by weighting the change in the burst overflow rate of the newly set call bundle or the released call bundle to the burst overflow rate of the set call bundle by the ratio of the old and new cell traffic amounts. it can. Further, in the present invention, the probability that the number of cells arriving within a certain fixed time is equal to or more than a fixed number is used as a parameter when calculating the change in the burst overflow rate of the newly set call bundle or the released call bundle. Therefore, it is possible to handle any call with no limitation in speed or generation mode.

In the call admission control system according to the third aspect of the invention, the call capacity of the target call type is increased when the number of call bundles is increased without making a one-to-one correspondence between the call capacity of the target call type and the number of call bundles. And the call capacities of the target call types when reducing the number of call bundles are set to different values,
By providing a hysteresis in the relationship between the call capacity of the call type of interest and the number of call bundles, a small change in the call capacity of the call type of interest is repeated near the transition point where the number of call bundles changes. However, the number of call bundles is fixed, and the setting and cancellation of call bundles are not frequently repeated each time the number of call bundles changes.

In the call admission control system according to the fourth aspect of the present invention, the number of call bundles when the call capacity of the noticeable call type increases without making the call capacity and the number of call bundles of the noticed call type correspond one-to-one. And the decrease amount of the number of call bundles when the call capacity of the target call type decreases, so that there is a hysteresis in the relationship between the call capacity of the target call type and the number of call bundles. By doing so, even if the call capacity of the call type of interest changes repeatedly near the transition point where the number of call bundles changes, the number of call bundles is fixed, and call bundles are frequently set and released at each change. It won't repeat.

[0029]

EXAMPLES Example 1. An embodiment of the first invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining the concept of a call bundle. In the figure, 1 represents a call and 2 represents a call bundle. 2A and 2B are diagrams for explaining a call and a call bundle in a link, in which 1a is a call of a call type a, 1b is a call of a call type b,
Reference numeral 2a represents a call bundle of call type a, 2b represents a call bundle of call type b, and 3 represents a link.

1 and 2, for call type a, six calls are grouped together into one call bundle, and for call type b, three calls are grouped together into one call bundle. FIG. 2A shows an example of a call bundle group, in which there are two call bundles of call type a and call type b.
1 shows a call bundle group set in the link.
If a new call of call type a occurs here, there is still room in the link, so it is possible to set a new call bundle 2a as shown in FIG. 2B and accept the new call. it can.
On the contrary, in the state of FIG. 2B, when one call of the call type a is terminated, 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 similar to that of the conventional example. 4A and 4B are flowcharts of the processing at the time of call reception. In FIG. 4A, in step (ST1), it is determined whether or not the new call fits in the existing call bundle. If it stops, step (ST2)
In step ST3, if the call admission is permitted and the new call bundle is set, the burst overflow rate BT is calculated.

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

FIG. 4B is a flow chart of the processing at the time of call disconnection. In step (ST7), it is judged 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, and in step (ST3b), the burst overflow rate BT when the call bundle is released is calculated.

Example 2. In the above embodiment, whether or not the value of the burst overflow rate is less than or equal to the reference value is used to determine whether or not a new call bundle can be set, but this is not necessary, and other determination criteria may be used. .

Example 3. Next, an embodiment of the second invention will be described with reference to the drawings. In the second invention, the step (ST3) of FIG. 4A and the step (ST) of FIG.
The method of calculating the burst overflow rate in 3b) is specifically described. Both the step (ST3) of FIG. 4A and the step (ST3b) of FIG. 4B call the same BT update flowchart shown in FIGS. 5 and 6.

FIGS. 5 and 6 are flowcharts of the burst overflow rate BT, which is the center of the present invention. Figure 7
Is a flowchart of initial setting of BT. Since the method of the present invention uses 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 past have the same meaning. This is the ratio of the ON state 12 and the ON state 12 plus the OFF state 13 of FIG. 3, that is, T1 (J) / T2 (J) is set to R (J). J represents a call type.

In the present embodiment, in order to express the cell arrival interval TM (J) in the ON state of FIG.
And the velocity coefficient A (J) are used. Speed 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 fast TM
The smaller (J) is, the larger A (J) is. BT is the burst overflow rate, ρ is the cell traffic amount, ρ _n is the updated value of the cell traffic amount, and M (J) is the number of calls in one call bundle of the call J.

In the algorithm of the present embodiment, both the value before updating and the value after updating are used for the cell traffic amount, so ρ and ρ _N are distinguished. G indicates the call type of the call that occurs or ends. G is an element of the set of call type 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). For S (H), since both the value before update and the value after update are used, S (H)
Distinguish between (H) and S _N (H). HMAX indicates the theoretical maximum value of H, and HM indicates the maximum value set for the convenience of processing H.

Next, a method of updating the burst overflow rate BT shown in FIGS. 5 and 6 will be described. First step (ST15)
Select whether the update is due to a call originating or ending. If it is caused by a call, the cell traffic amount ρ is first updated in step (ST16). That is, the amount of cell traffic of the already set call is stored in ρ, and the increment M of the amount of cell traffic due to the newly generated bundled call of the call G is stored therein.
(G) × A (G) × R (G) / T is added to obtain a new ρ _n . If expressed by an equation, ρ ← ρ _n , ρ _n ← ρ + M (G) ×
It becomes A (G) × R (G) / T.

Next, at step (ST17), the burst overflow rate BT of the preset call and the burst overflow rate increment by the newly generated call bundle are incremented.

[0041]

[Equation 2]

Is weighted and added by the ratio ρ / ρ _N of the old and new cell traffic amounts, and the value of the burst overflow rate BT is updated. If it is expressed by a formula

[0043]

[Equation 3]

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

This update formula is

[0046]

[Equation 4]

It is However, S (H) is defined only when H is positive, and when H is negative, S (H) = 1. In addition, since it is impossible to make H infinitely large in the calculation processing, if H exceeds the upper limit HM in the processing, S
(H) = 0.

When it is determined in the above step (ST15) that the update is due to the end of the call, the 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 H or more is
It is updated as shown in FIG. 6 in consideration of the case of a call and inside out. 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 is H or more are recurrently updated. Need to set their initial values.

This initial value is shown in FIG. Step (ST
22), the initial value of the cell traffic volume is ρ _N =
ρ = 0, the initial value of the burst overflow rate is BT = 0, and the initial value of the probability S (H) that the number of cells arriving within the period T is H or more is set to S (H) = 0. The initial value of S (H) is set within the range of 0 ≦ H ≦ HM that H can take. In addition,
The order of setting these initial values is arbitrary.

The call admission control method in this embodiment is summarized as 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, call acceptance judgment is performed according to FIG.

First, in step (ST1), it is judged whether or not the new call fits in the current call bundle. If the new call fits, the call acceptance is permitted in step (ST2). If it does not fit, a new call is made in step (ST3). BT when call bundle is set
Are updated by the procedure shown in FIG. 5 and FIG.
Proceed to 4) to determine whether BT is less than or equal to the specified value, and if it is less than or equal to the specified value, proceed to step (ST5) to set a new call bundle, and permit call acceptance in step (ST2).
If BT is equal to or greater than the specified value, call acceptance is rejected in step (ST6). Further, when disconnecting the set call, it is determined whether or not there is an empty call bundle in step (ST7) of FIG.
Proceeding to 8), one call bundle is released, and in step (ST3b), BT is updated by the procedure shown in FIG.

In the conventional example, the calculation of the burst overflow rate BT, which had to follow the flowchart of the multiple nesting structure shown in FIGS. 16 to 21, can be performed only by the procedure shown in FIGS. 5 and 6 in the present embodiment. You can do it.

Example 4. In the above-mentioned embodiment, all the procedures are shown by the flow charts by software, but some or all of them may be realized by hardware.

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

Example 6. Further, in the above embodiment, the parameter H is limited by the upper limit value HM in processing, 0 ≦ H ≦ HM
Although the range of is changed, step (ST23) of FIG.
As shown in step (ST26), the value of the theoretical maximum value HMAX of H is calculated, and step (ST1 of FIG.
8), and update S (H) in step (ST21) to 0
If performed within the range of ≤H≤HMAX (step (ST
18), step (ST21)), the calculation time can be further shortened.

Example 7. In addition, the step (ST2
4), and overflow processing of the value of H as shown in (ST25) may be added.

Example 8. An embodiment of the third invention will be described below with reference to the drawings. FIG. 9 is a diagram showing a call admission control system according to an embodiment of the present invention. In the figure, (a) shows an algorithm at the time of calling, and (b) shows an algorithm at the time of ending the call. Figure 1
0 is a diagram showing the relationship between the call capacity of the target call type and the number of call bundles in the embodiment, the horizontal axis of the figure shows the call capacity of the target call type, and the vertical axis shows the number of call bundles. In the figure, 101 is a graph showing the relationship between the call capacity of the target call type and the number of call bundles, and 102a to 102e are the numbers when the number of call bundles changes from 1 to 2, 2 to 3, 3 to 4 and 4 to 5, respectively. A representation of the route, 103a-10
Reference numeral 3e represents a route when the number of call bundles transits from 2 to 1, 3 to 2, 4 to 3, 5 to 4. In the figure, the upper ends of 102a to 102e are hollow white circles and the lower ends are black circles, which means that when the value of the call capacity of the call type of interest increases, the call bundle is above any of 102a to 102e. The number indicates that it takes the value indicated by the black circle at the bottom. The fact that the upper ends of 103a to 103e are black circles and the lower ends are hollow white circles means that when the value of the call capacity of the call type of interest decreases, when it is above any of 103a to 103e, the number of calls Indicates that the value indicated by the black circle at the top is taken.

Next, the algorithm of this embodiment will be described. In FIG. 9 (a), when a new call is made, it is determined in ST1 whether or not there is room to accommodate the new call in the call bundle currently set. S
Accepting a new call that arrives after advancing to T2 is permitted. If there is no room, go to ST3. In ST3, the burst overflow rate BT when a new call bundle is set is calculated. As a result, it is determined in ST4 whether or not the burst overflow rate BT is below a specified value. When it is determined in ST4 that the burst overflow rate BT is less than or equal to the specified value, the process proceeds to ST5, a new call bundle is set, and call acceptance is permitted in ST2. If it is determined in ST4 that the burst overflow rate BT is greater than or equal to the specified value, ST
The process proceeds to 6 and the call acceptance is rejected. In this embodiment, the call connection process is the same as in the case of FIG.

In FIG. 9B, in ST7, it is determined whether or not there is an empty call bundle due to the end of the call. 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 bundle, it is possible to cancel the empty call bundle. However, immediately without canceling the empty call bundle, the process proceeds to ST7b and the call bundle is cleared. 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 bundle, ST8
Go to and release one call bundle. If the safety margin SM is not left when one call bundle is released, the call bundle is not released and is left as it is. After releasing one call bundle in ST8, ST
In 3b, the burst overflow rate when the call bundle is released is calculated, and the call disconnection process is terminated.

In the conventional example, the number of call bundles and the call capacity of the target call type have a one-to-one correspondence, and whether the call capacity of the target call type increases or decreases, the specific target call type While the number of call bundles corresponding to the call capacity of No. 1 is 1, the graph 101 showing the relationship between the call capacity and the number of call bundles of the call type of interest in FIG. It can be seen that the routes are different when the call capacity increases and when it decreases. For example, if the call capacity of the call type of interest increases from zero, CC1-p
When (p ≦ SM) is reached, the number of call bundles is one. When the call capacity of the call type of interest increases and reaches CC1, the number of call bundles increases by 1 to 2. When the call capacity of the call type of interest further increases to CC1 + p, the number of call bundles is still 2. Here, the call capacity of the target call type decreases and CC1
Even if it becomes -p, the number of call bundles remains 2. 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,
There is no frequent transition between 1 and 2.

Example 9. Further, in the above embodiment, the case where the boundary points at the time of transition of the number of call bundles are as shown in FIG. 10 has been described, but 102a to 102e and 103a to 1 in FIG.
The combination of black circles and white circles above and below 03e is not limited to this, and other combinations may be used. There are four effective combinations including the example of FIG. 10, and another example is shown in FIG. FIG. 11 is a diagram showing the relationship between the call capacity of the call type of interest and the number of call bundles. 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, similar to FIG. . In the figure, 111 is a graph showing the relationship between the call capacity of the target call type and the number of call bundles, and 112a to 112e each have a call bundle number of 1
To 2, 2 to 3, 3 to 4, 4 to 5 transitions, 113a to 113e have call bundle numbers of 2 to 1, 3 to 2, 4 to 3, 5 to 4 respectively. It shows the route when making a transition. In the figure 112
The fact that the upper ends of a to 112e are hollow white circles and the lower ends are black circles means that the value of the call capacity of the target call species increases.
When it is above any of 2a to 112e, it indicates that the number of call bundles takes the value indicated by the black circle at the lower end. Again 11
The fact that the upper ends of 3a to 113e are hollow white circles and the lower ends are black circles means that when the call capacity of the target call type decreases,
When it is above any of a to 113e, it indicates that the call bundle number takes the value indicated by the black circle at the lower end.

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

Example 11. In the above-mentioned Examples 8, 9 and 10, the case where the number of call bundles in the call bundle group is increased or decreased is described as a unit of one call bundle, but the number of call bundles to be increased or decreased need not be constant. It doesn't matter if it changes. For example, the number of call bundles may be set to 4 from the beginning, and then, when the number of calls is increased, the number of calls may be changed from 4 to 4 + 2, and then to 4 + 2 + 1, so that the increment width may be variable. Alternatively, the range of increase / decrease may be appropriately changed depending on the use time zone and the past use situation.

Example 12 Next, an embodiment of the fourth invention will be described. In the above Examples 8, 9, and 10,
Although the case where the increase width and the decrease width of the call bundle number are the same is shown, the increase width and the decrease width may be changed. For example, consider the case where the increment is 1 and the increment is 2. FIG.
In the case where the call capacity is increased to 5 as in the conventional case, conventionally, when the call capacity is decreased to CC4, the number of call bundles is decreased by one. If 2 is set, the number of call bundles will not be decreased until 2 can be afforded. Therefore, the number of call bundles decreases from 5 to 3 when the call capacity becomes CC3 or less.

Therefore, the call capacity varies from CC3 to CC5.
When the number of calls increases, the call capacity increases from CC5 to C
The decreasing path when decreasing to C3 is different, and the relationship between the two can have the hysteresis as shown in Examples 8, 9, and 10. In other words, the call capacity when increasing the number of call bundles is CC1, CC2, CC
3, ..., 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 call bundles, that is, capacities of 3, 5, and 7, and CC2, CC4, CC6,
Therefore, the call capacity is not frequently increased or decreased, and the same operational effect as the present invention is obtained.

Example 13. Next, another embodiment of the fourth invention will be described. FIG. 14 shows an embodiment in which the safety margin SM is increased. In the tenth embodiment, the safety margin width SM is equal to the maximum number of calls in the call bundle, but the safety margin width SM may be larger than the maximum number of calls in the call bundle in this way. However, when the safety margin width SM is larger than the maximum number of calls in the call bundle, it is desirable from the viewpoint of line usage efficiency that the reduction width is also larger than the maximum number of calls in the call bundle. In this example, the increase width is 1 and the decrease width is 2.

As described above, in the call admission control system according to the third and fourth inventions, the call admission control system using the call bundle in the asynchronous transfer system network, that is, the asynchronous transfer system network receives the call from the user. A call admission control method that determines whether or not there is a margin.A call bundle is a set of a certain number of calls that are classified by call type.When a new call occurs, if a new call fits in the existing call bundle, immediately If the call is accepted and it does not subside, it is judged whether there is enough bandwidth to set a new call bundle. If there is a margin, a new call bundle is set and the above new call is accepted If there is no call, the above-mentioned new call acceptance is rejected, and at the end of the call, if there is an empty call bundle due to the end of the call, the call bundle is released. In the control method, whether or not a new call fits in the existing call bundle at the time of calling When disconnecting and when determining whether or not the call bundle can be released at the end of the call, the call of the same call type of interest does not correspond to the number of call bundles and the call capacity of the call type of interest. Even if the number of call bundles corresponding to the capacity of the target call type increases, the number of call bundles when the call of the target call type increases, that is, when the call capacity of the target call type decreases, that is, the number of call bundles when the call ends. Is set to a different value, and even if there is a call bundle that becomes empty when the call ends, it is not released immediately, and there is a hysteresis in the relationship between the call capacity of the target call type and the number of call bundles. To do.

In the above embodiment, the case where the number of call bundles is increased / decreased has been shown, but the number of call bundles may be increased / decreased at a predetermined rate with respect to the number of call bundles already used. . For example, the number of call bundles may be increased or decreased by 20% of the current number of call bundles (rounded to the nearest whole number).

[0069]

As described above, according to the first aspect of the present invention, a certain number of calls are grouped into a call bundle according to the call type, and the reference parameter for determining whether to accept or reject a call is updated for each call bundle. As a result, there is an effect that the call admission judgment at the time of the call occurrence becomes very simple and the call admission control time is significantly shortened.

According to the second aspect of the present invention, the burst overflow rate is used for determining whether or not the call bundle can be set, and the burst overflow rate can be easily calculated by the recursive method. There is an effect that the call admission control can be performed at high speed while considering the statistical multiplexing effect between them.

According to the third aspect of the present invention, the call capacity of the target call type is increased when the number of call bundles is increased without making the call capacity of the target call type correspond to the number of call bundles. , And the call capacity of the target call type when reducing the number of call bundles is set to a different value, and a hysteresis is added to the relationship between the call capacity of the target call type and the number of call bundles. Even if the call capacity of the call type of interest changes repeatedly near the transition point where the number changes, the number of call bundles does not change each time and the call bundle is not frequently set and released. This has the effect of reducing the processing amount associated with setting / cancellation of, and thus reducing the amount of software and the hardware circuit scale.

Further, according to the fourth aspect of the present invention, even if the call capacity of the call type of interest and the number of call bundles do not correspond one-to-one, the number of call bundles corresponding to the call capacity of the same call type of interest , When the call capacity of the target call type increases, that is, the number of call bundles when a new call arrives, and when the call capacity of the target call type decreases, that is, when the call leaves, the number of call bundles is set to different values. Since the relationship between the call capacity of each type and the number of call bundles has hysteresis, even if the call capacity of the target call type changes repeatedly near the transition point where the number of call bundles changes, When the number of call bundles changes,
The release is not frequently repeated, which reduces the amount of processing required for setting and releasing the call bundle, which in turn reduces the amount of software and the hardware circuit scale.

[Brief description of drawings]

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

FIG. 2 is a diagram illustrating a call and a call bundle in 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 flow chart diagram of processing at the time of accepting a call and at the time of disconnecting a call according to the embodiment of the present invention.

FIG. 5 is a burst overflow rate BT according to an embodiment of the second invention.
It is a flowchart figure of update.

FIG. 6 is a burst overflow rate BT according to an embodiment of the second invention.
It is a flowchart figure of update.

FIG. 7 is a flow chart diagram of burst overflow rate BT initial setting of the embodiment.

FIG. 8 is a flow chart of another embodiment of the second invention.

FIG. 9 is a flowchart showing an algorithm of a call admission control system according to an embodiment of the third invention.

FIG. 10 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 system according to the embodiment.

FIG. 11 is a flowchart showing an algorithm of a call admission control system according to another embodiment of the third invention.

FIG. 12 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 system according to another embodiment of the third 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 system according to the embodiment of the fourth invention.

FIG. 14 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 system according to another embodiment of the fourth invention.

FIG. 15 is a flowchart of conventional call admission judgment.

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

FIG. 17: Expected value E of burst overflow rate in a conventional example
It is a flowchart figure of PT calculation and a cumulative addition subroutine.

FIG. 18 is a flowchart of a total SUM calculation subroutine for the number of arriving cells in the 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 that takes N (J) to I (J) in the conventional example.

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

[Explanation of symbols]

1 call 1a call type 1 call 1b call type b call 2 call bundle 2a call type a call bundle 2b call type b call bundle 3 link ST1 judgment whether new fits in existing call bundle ST2 call admission 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 acceptance rejection ST7 Whether there is an empty call bundle during call disconnection processing Judgment ST7b When one call bundle is released, it is judged whether or not there is a safety margin SM ST8 Release of call bundle ST16 Update of cell traffic amount ρ when call bundle is set ST17 Burst overflow rate BT when call bundle is set Update ST18 The number of cells arriving within the period T when the call bundle is set is H
Update of probability S (H) of being more than or equal to ST19 Update of cell traffic amount ρ when releasing call bundle ST20 Update burst overflow rate BT when releasing call bundle ST21 Number of cells arriving within period T when releasing call bundle H
Update 101 of probability S (H) of not less than 100 Graphs representing the relationship between the call capacity and the number of call bundles of the call type of interest, 1102a to 102e, respectively. Representation of routes when transiting from 4 to 5 103a to 103e Representation of routes when transition of call bundle number from 2 to 1, 3 to 2, 4 to 3, 5 to 4 respectively

Claims (4)

[Claims] 1. A call admission control method for placing a network in an asynchronous transfer system and determining whether or not the network has room to accept a call from a user. When a new call occurs, it is accepted immediately if a new call falls within the current call bundle, and if it does not subside, a new call bundle is set to determine whether there is enough bandwidth. If there is a margin, a new call bundle is set and the above new call is accepted, and if there is no margin, the acceptance of the above new call is rejected. The call admission control method is characterized in that when there is a call bundle, the call bundle is released. 2. The call admission control method according to claim 1, wherein a burst overflow rate serving as a criterion for determining the possibility of setting or releasing the call bundle is calculated, and a new call bundle A means for determining whether it has occurred or cancellation of the call bundle, and at the time of setting a new call bundle, add the increment of the cell traffic amount of the new call bundle to the cell traffic amount of the existing call bundle to obtain the new cell traffic amount. Means, means for updating the burst overflow rate by weighted addition by the burst overflow rate of the already set call bundle and the increment of the burst overflow rate of the newly set call bundle, and the ratio of the new cell traffic amount and the old cell traffic amount obtained above. And, at the time of releasing the call bundle, means for obtaining a new cell traffic amount by subtracting the decrement of the cell traffic amount of the released call bundle from the cell traffic amount of the preset call bundle, and a burst overflow rate of the preset call bundle. And a decrement of the burst overflow rate of the terminated call bundle, by means of weighted addition with the ratio of the new cell traffic amount and the old cell traffic amount obtained above, and means for gradually updating the burst overflow rate, A call admission control method characterized by using a probability that the number of cells arriving within a certain period is equal to or less than a certain number as a parameter for calculating a change amount of a burst overflow rate when a bundle is newly set or released. 3. A call admission control method comprising the steps of: (a) increasing the number of call bundles in a call bundle group by a predetermined amount when the call capacity in the call bundle group reaches a predetermined criterion. And (b) when the call capacity in the call bundle group decreases and a predetermined criterion different from the predetermined criterion when the number of call bundles in the call bundle group is increased in the increasing step is reached, A reduction process for reducing the number of call bundles in a bundle group. 4. A call admission control method comprising the steps of: (a) increasing the number of call bundles in a call bundle group by a predetermined amount when the call capacity in the call bundle group reaches a predetermined criterion. The step (b), when the call capacity in the call bundle group is reduced and a predetermined criterion different from the predetermined criterion when the number of call bundles in the call bundle group is increased in the increasing step is reached, the increase is made. A reduction step of decreasing the number of call bundles of the call bundle group by a predetermined amount different from the predetermined amount when the number of call bundles of the call bundle group is increased in the step.