JP3085517B2 - ATM band regulator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for an asynchronous transfer mode (ATM) network.
The present invention relates to an improvement in a technique for restricting a large amount of information from being simultaneously transmitted to a plurality of virtual channels.

[0002]

2. Description of the Related Art In asynchronous transfer mode (hereinafter referred to as ATM) communication, communication is performed by transmitting and receiving fixed-length packets called cells. This conventional example will be described with reference to FIGS. FIG. 5 is a conceptual diagram of an ATM network. FIG. 6 is a conceptual diagram of a virtual path (hereinafter, referred to as VP) and a virtual channel (hereinafter, referred to as VC). FIG. 7 is a conceptual diagram of a conventional band regulation. As shown in FIG.
In the TM network, ATM exchanges accommodating terminals are connected by a physical transmission line, and a VP as shown in FIG.
And VC are set. A plurality of VCs are further set in the set VP. Each VC can change its band according to the amount of cells flowing therethrough as shown in FIGS. 6 (a), 6 (b) and 6 (c).

In response to a call setting request from a user, the ATM switch determines that the required quality can be protected from the current network usage state even if the call is accepted, and anticipates the statistical multiplexing effect. Call connection is performed by performing stochastic bandwidth allocation to the user in VC units. However, at the time of accepting a call, unexpected quality of burst traffic may make it impossible to satisfy the required quality. In such a case, as shown in FIG. 7, in the conventional example, V is controlled by an instruction from call processing software.
UPC (Usage Parameter Control) that monitors bandwidth for each C
l) The bandwidth used in the network is restricted by changing the bandwidth to be smaller than the bandwidth to be monitored by the network for any VC already connected in the unit 14 to reduce the bandwidth allowed for this VC. And performs processing to eliminate the congestion state in the network (FIGS. 7 and 7). Specifically, cells exceeding the band are discarded according to the determination of the determination unit 147.

[0004] On the other hand, the congestion control release decision is made periodically by using call processing software 2 to collect traffic information that can be collected by the exchange.
After the call processing software 210 determines that the congestion state in the network has subsided, the call processing software 210 cancels the band regulation processing in the UPC unit 14 again according to the instruction of the call processing software 210. At this time, the bandwidth monitoring information set at the time of connection of this VC is reset for each VC that has performed the bandwidth change (FIG. 7).

[0005]

When such congestion occurs, the VC is controlled according to an instruction from the call processing software.
In the method of executing the band restriction by changing the information set at the time of the call connection, the band restriction execution instruction is performed in units of VCs. This puts a burden on the processing. Further, the congestion release determination and the process of restoring the setting information also depend on the call processing software, so that the processing capability of the call processing software at the time of congestion may be squeezed.

[0006] Further, if the band regulation is set to 100%, the communication of this VC is interrupted. If the communication is interrupted for a long time, the AAL (ATM Adaptation) of the signal protocol is used.
In some cases, the keep-alive timer that monitors the normality of the call connection may be exceeded, and in that case, the connection with the VC network is automatically disconnected. In this case, after the congestion is released, the call processing software must newly set not only the bandwidth monitoring information but also header conversion information and other call connection information of this VC.

SUMMARY OF THE INVENTION The present invention has been made in such a background, and is an ATM band regulating apparatus capable of autonomously regulating a VC band in hardware without placing a burden on call processing software. The purpose is to provide. The present invention provides an AT that allows a large number of VCs that commonly use a physical channel to execute appropriate regulation independently at the position of the physical channel without affecting others.
An object is to provide an M band regulating device. SUMMARY OF THE INVENTION It is an object of the present invention to provide an ATM band restricting apparatus in which a communication connection state is not released by restricting. A
It is an object of the present invention to provide an ATM band regulation device that does not prevent a TM communication user from being unable to perform communication for an unreasonably long time due to band regulation.

[0008]

In order to solve the above-mentioned problems, the present invention provides a plurality of bandwidth-regulated management tables for managing VCs to be band-limited for each arbitrary group among VCs that can be communicated, The main feature is that a batch of VCs stored in the bandwidth regulation management table that exists when a regulation process is executed is collectively prohibited from being blocked in a rotation for each bandwidth regulation management table.

That is, the present invention provides an ATM provided with a band regulating means for regulating a VC band so that the sum of a plurality of VC bands does not exceed a predetermined allowable band.
It is a band regulating device. The feature of the present invention resides in that the plurality of VCs are divided into two or more groups, and a means for cyclically regulating each group is provided.

As a result, the VC to be restricted is determined for each group, and the group automatically transitions cyclically. Therefore, the load on the call processing software described in the conventional example is limited to the start or stop of the execution of the restriction. And significantly reduced as compared with the conventional example.

[0011] It is desirable that the continuous maximum regulation time of one group is set shorter than the set communication release time.

As a result, a situation in which a VC during communication is disconnected even if the restrictions are imposed to the maximum can be avoided.
Therefore, the call processing software does not spend time for resetting the VC.

Preferably, the grouping of the VCs is recorded in a table in advance. Group size,
Alternatively, group setting such as group formation may be set by estimating an optimum one with reference to the congestion state and other histories so far, and creating a table for each group.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.

The present invention relates to an ATM band restricting apparatus provided with an input restricting section 12 as a band restricting means for restricting a VC band so that the sum of a plurality of VC bands does not exceed a predetermined allowable band. is there.

Here, a feature of the present invention is that the plurality of VCs are divided into two or more groups, and a time management unit 1 as means for cyclically regulating each group.
1, a connection information reading unit 121 and a table search counter 122 are provided.

According to the present invention, a plurality of band regulation management tables #N (N = 1, 2,...) For managing VCs subject to input regulation, VC
The input control unit 12, the clock generator 111, and the timer 110, which execute the cell flow monitoring and input control for each cell, constitute hardware for band control. The band regulation control is executed by a control unit based on the hardware and the call processing software 210. The timer 110 is incremented by the clock generator 111 and is cleared to "0" when it reaches a certain value. The hardware that has received the input restriction instruction from the call processing software 210 activates the timer 110.
Each time the table search counter 122 receives an enable signal generated at a constant period from the timer 110, it increments by “+1”.
Count up by one. Input control VC from counter value
Is determined, and the input restriction unit 12 executes input restriction only for VCs held in the band restriction management table #N.

After a predetermined period of time elapses, the timer 110 that is being activated clears the timer 110 to “0”, and the table search counter 1 of the input restriction unit 12.
An enable signal for counting up is output to 22. The timer 110 repeats this operation until the call processing software 210 issues an input restriction release instruction. This fixed time is set within a range not exceeding the keep-alive timer for monitoring the normality of the call connection in the AAL of the above-described signaling protocol. Therefore, a situation in which the connection of the VC is released by performing the band restriction does not occur.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a flowchart showing a table determination procedure. FIG. 3 is a block diagram of the input restriction unit 12. As shown in FIG. 1, the apparatus according to the embodiment of the present invention includes a bandwidth regulation management table #N, an input regulation unit 12, and a time management unit 11. The time management unit 11 includes a timer (TIM) 110 for holding the input restriction time and a clock generator (CLK).
111. The input restriction unit 12 is a cell drop circuit 1
20, a connection information reading unit 121, a table search counter 122, and an input restriction determination circuit 123.

The call processing software 210 establishes a connection type (VPI /
VCI information, etc.). At this time, VCs for which input provisions are to be made are arbitrarily grouped and registered in a plurality of bandwidth regulation management tables #N (FIG. 1). The setting of the group such as the size of the group or the organization of the group may be set by estimating the optimum one with reference to the congestion state and other histories so far and creating a table #N for each group. A VC (for example, police or fire line) that does not perform band regulation need not be registered in the band regulation management table #N.

Call processing software 21 receiving congestion information
In the case of 0, a band regulation execution instruction (timer activation instruction) is issued to the time management unit 11, whereby the timer 110 is activated. At the same time, the VPI / VC shown in FIG.
A reset instruction for clearing the memory of the I management table 130 is issued (FIG. 1). The memory clear is performed only in response to a band regulation execution instruction and a stop instruction from the call processing software 210.

The timer 110, which has received the activation instruction, is stepped up by receiving the clock from the clock generator 111, and when its value reaches a value set in advance by the call processing software 210, clears its own value to zero and simultaneously controls input. The table search counter 122 in the unit 12 is set to “+”.
An enable signal for counting up by 1 "is output. Also, the clock generator 111 generates a clock having a fixed period. Therefore, after the timer 110 is instructed to start, the timer 110 is activated at every fixed period set by the call processing software 210. Output an enable signal.

Upon receiving the enable signal, the table search counter 122 adds “+” to the held counter value.
The VC group that executes the input restriction, that is, the reference band restriction management table number is determined by the arithmetic circuit 129 based on the counter value, and the band restriction management table having the determined band restriction management table number is calculated. The VPI / VCI information is read from # N.A flow chart of the mechanism corresponding to the counter value and the bandwidth regulation management table #N to be referred to is shown in Fig. 2. Here, the number of groups (the number of bandwidth regulation management tables) created by the call processing software 210. Is assumed to be smaller than the maximum number that can be counted by the table search counter 122. The connection information reading unit 121 compares the counter value with the number m of the band regulation management tables, and when the counter value is smaller than m, (S
1) The connection type held in the band regulation management table #N assigned the same number as the counter value read value is read (S2). On the other hand, if the counter value is greater than m, the bandwidth regulation management table #N to be referred to is specified according to N = counter value−n × m (S3). Starting from n = 1, n is incremented until the condition of N <m is satisfied (S4 to S7). When the condition of N <m is satisfied, the value of N is the reference band regulation management table number.

The input restricting section 12 executes an input restricting process based on the contents of the reference band restriction management table #N. Specifically, the VP of the cell passing through the cell drop circuit 120
The I / VCI information and the VPI / VCI information read from the bandwidth regulation management table #N are compared and referenced by the input regulation determination circuit 123, and only the cells having the corresponding VPI / VCI information are discarded by the cell drop circuit 120.

The internal operation of the input restriction unit 12 will be described with reference to FIG. The header information of the cell input to the input control unit 12 is copied from the cell extractor 124 in the cell drop circuit 120. The copied header information is stored in the VPI / VCI read result holding register 12 in the input restriction determination circuit 123.
7 is held. The comparator 126 stores the VPI / VCI information held in the VPI / VCI read result holding register 127 and the VPI / VCI management table 13 read from the bandwidth regulation management table #N by the connection information reading unit 121.
Compare VPI / VCI held at 0. As a result, if there is a matching VPI / VCI, the VPI / VCI is set in the cell filter 125 and the VPI / VCI is set.
Only cells with PI / VCI are dropped. Processing from cell extraction (copy processing) to setting of the cell filter 125 is performed within one cell transfer time. Note that VPI / VCI
The management table 130 is a bandwidth regulation management table # 0 to #N
It is easy to use them together.

According to the present invention, the bandwidth regulation management tables # 0 to # 0
FIG. 4 shows how the bandwidth of the VC registered in # 2 changes.
FIG. 4 is a diagram showing a state of a VC band fluctuation. In FIG. 4, for the sake of explanation, the number of bandwidth regulation management tables is 3, and the number of VCs registered in the bandwidth regulation management tables # 0 to # 2 is 3 each.
And The bandwidth regulation management table number to be referred to is determined from the table search counter value.
In the case of, the VC registered in the bandwidth management table # 0
Only for a certain period of time, input restriction is executed. This fixed time is set within a range not exceeding the keep-alive timer for monitoring the normality of the call connection in the AAL of the above-described signaling protocol. Therefore, by regulating the band, V
A situation in which the connection of C is released does not occur.
After a certain period of time, the table search counter 122 indicates "+
In this case, the bandwidth regulation management table to be referred to is changed to # 1. At this time, the input regulation of the VC registered in the bandwidth regulation management table # 0 is released, and the bandwidth before the input regulation is released. At the same time, input control is performed on VCs registered in the bandwidth control table # 1.
Are sequentially executed until a release instruction is issued. Note that a VC that is not subject to band regulation can secure a predetermined band even during the execution of this processing. Call processing software 21
0 is a band regulation stop instruction (a timer stop instruction and a reset instruction to the input restriction unit) when the input restriction becomes unnecessary.
I do.

[0027]

As described above, according to the present invention,
The VC band can be regulated autonomously in the hardware without placing a burden on the call processing software.
ADVANTAGE OF THE INVENTION According to this invention, many VCs which use a physical channel in common can perform appropriate regulation independently in the position of the physical channel, without affecting others. Further, according to the present invention, the connection state of the communication is not released by performing the regulation. Furthermore, there is no possibility that communication cannot be performed for an unreasonably long time due to band regulation.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a table determination procedure.

FIG. 3 is a block diagram of an input restricting unit.

FIG. 4 is a diagram illustrating a state of a VC band fluctuation.

FIG. 5 is a conceptual diagram of an ATM network.

FIG. 6 is a conceptual diagram of VP and VC.

FIG. 7 is a conceptual diagram of a conventional band regulation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Time management part 12 Input control part 14 UPC part 110 Timer 111 Clock generator 120 Cell drop circuit 121 Connection information reading part 122 Table search counter 123 Input restriction determination circuit 124 Cell extractor 125 Cell filter 126 Comparator 127 VPI / VCI Read result holding register 128 VPI / VCI read circuit 129 Arithmetic circuit 130 VPI / VCI management table 147 Judgment unit 210 Call processing software # 0, # 1, # 2, #N Bandwidth regulation management table

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04L 12/28 H04L 12/56

Claims (2)

(57) [Claims] 1. Sum of bands of a plurality of virtual channels
Bar so that it does not exceed the predetermined allowable bandwidth.
Equipped with band regulation means to regulate the band of the channel
In the ATM band regulating device obtained, the plurality of virtual channels are divided into two or more groups.
And provide a means of providing cyclical regulation for each group.
e, The maximum continuous time for one group is
The time is set shorter than the time when the Characterized by
ATM band regulator. 2. The AT according to claim 1, wherein the grouping of the virtual channels is recorded in a table in advance.
M band regulation device.