JPH07254905A - Call reception controller - Google Patents

Abstract

PURPOSE:To improve the utilizing efficiency of incoming/outgoing VPs by taking a band of an outgoing VC and a status of an outgoing VP into account in the case of receiving and discriminating an incoming VC and taking a band of an incoming VC and a status of an incoming VP into account in the case of receiving and discrimianting an outgoing VC. CONSTITUTION:A call reception controller 301 connecting to a pre-stage exchange or a terminal equipment and a post-stage exchange or a terminal equipment through signal lines 308, 309 set separately from a call via a receiver 302. Incoming/outgoing VC band information included in a connection request is stored in a storage device 303. A classifving device 304 compares a VC band of the connection request call with the stored VC band to classify the call. A device 305 stores a number of classes connected and a device 306 transfers a reception enable signal when the connection request call is within the range of a class dependent receptible number and a reception disable signal when not to a signal transmitter 307. Thus, narrow band VCs are connected to some degrees, the VC is not accepted and a broad band VC is accepted while leaving a residual band of the VP.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a call admission control device in an ATM switch in an ATM network which provides communication in a plurality of bands.

[0002]

2. Description of the Related Art ATM (Asynchronous Transfer Mode) divides a wide variety of information into short fixed-length blocks with headers called "cells" and multiplexes them by an efficient statistical multiplexing method. To do. Cells are dynamically allocated in response to time-varying demands for information transmission, and the communication speed can be variably set by changing the number of cells. Therefore, AT
M is a transfer mode in which all digital information from voice and data to images can be centrally transmitted.

As described above, in ATM, information can be transferred at an arbitrary transmission rate. A communication network that performs communication based on this ATM is called an ATM network. FIG. 1 is a diagram of a communication system forming an ATM network. The ATM network has user terminals (101, 102) used by users for communication and ATM exchanges (103, 104) for connecting the terminals. The communication between the terminal 101 and the terminal 102 is the VC set in each of the up and down directions.
(Virtual channel) (111-113, 114-116). A VP (virtual path), which is a path accommodating a VC, is provided in the vertical direction between the terminal / exchange and between the exchanges / exchanges (105-110).

FIG. 2 is a sequence diagram relating to information transfer in the ATM network. Switching device for connection request 201 from terminal 101
103 indicates whether the upper / lower VC pair (111,114) can be accepted for the upper / lower VP pair (105,108) between the terminal and the exchange, and the VC pair (112,115) can be accepted for the VP pair (106,109) between the exchanges. The connection request 202 requests the next connection control of the next-stage exchange 104. The exchange 104 judges whether the VC pair (113,116) is admitted to the VP pair (107,110), and if yes, calls the destination terminal 102 (204) and informs the pre-stage exchange 103 that the reception is possible (203).
103 provides a ring tone to the terminal 101 (205). Terminal 102
If is answered, the reply signal is forwarded (206-208),
After that, the user can transfer arbitrary information such as voice, data, and images until it is released (210-212) (209).
).

In the ATM network, a large number of cells are transmitted when a large amount of information such as an image is required to be transmitted, and a small number of cells are transmitted when a small amount of information needs to be transmitted, thereby realizing communication from a wide band to a narrow band. it can. In particular, for example, communication in which the vertical bands are different, such as an image from the center to the end direction and a voice from the end to the center direction, is allowed. In this case, the VC bands in the vertical direction are different. Further, the band for the VP accommodating the VC may be different at the upper and lower sides. Further, even when the same band is required for the upper and lower sides, there is a case in which the band actually received is different due to the effect called cell delay fluctuation.

[0006]

SUMMARY OF THE INVENTION Such a conventional AT
In the M network, the connection requests 201 and 202 have additional information about the VC band in the vertical direction, and the acceptance determination is performed based on that, but the acceptance determination logic is separately configured in the vertical direction.
For example, the downlink VC band, the downlink VP band, and the like are not taken into consideration when determining the acceptance in the uplink direction. Although there is a technique called bandwidth reservation for improving the communication condition of wideband calls in the admission logic, this also does not consider both directions.

An object of the present invention is not to perform call admission control independently in the up and down directions, but to consider a downlink for an up link and a uplink for a down link, and to provide a new call admission control for comprehensively controlling a call. It is to provide a control means.

[0008]

In the call admission control device of the present invention, the information of the upstream VC band and the information of the downstream VC band which constitute the call are received and held. Top and bottom VP usage status (eg number of calls in each class connected to the top and bottom VP, top and bottom VP
(Remaining bandwidth, etc.) of the call and the upper and lower VC bandwidth information are input to the call acceptance determination device, and the acceptance of the call is determined.

[0009]

In general, if the narrow band VC is accepted without limitation, the narrow band VC reduces the remaining band of the VP, the wide band VC cannot be accepted, and the use efficiency of the VP is lowered. Therefore, band reservation is introduced so that if the narrow band VCs are connected to some extent, no more narrow band VCs will be accepted. In the present invention, since the connection status of VCs in both directions is checked, it is possible to distinguish a narrow band call in the up direction and a wide band call in the down direction from a narrow band call in the up and down directions, for example, when determining whether to accept an upcoming VC. This is possible, and it is possible to prevent the upstream VC from being unacceptable for a call like the former due to bandwidth reservation.

[0010]

[Embodiment] Next, a first embodiment of the present invention will be described. FIG. 3 is a block diagram of an embodiment relating to the call admission control device,
The exchanges 103 and 104 are provided. The control device is connected to the pre-stage exchange (or terminal) and the post-stage exchange (or terminal) by the preset signal lines (signal VCs) 308 and 309, which are set separately from the call (VC) whose acceptance is to be accepted. There is. The connection requests 201 and 202 are sent to the in-switch call admission control device 301 via the signal line 308, and the receiving device 302 receives the connection request. Upper and lower V included in connection request signal
The C band information (A, B) is stored in the storage device 303. apparatus
304 has a device 401 (FIG. 4) that stores the relationship between the band class and the upper and lower VC bands. The comparator 402 compares for each i whether or not it matches the VC band (A _i , B _i ), and outputs the result to the device 306.

On the other hand, the device 305 is connected to each class.
There is a device 503 (Fig. 5) that stores the number of classes
It can be referred to from the device 306 by the outgoing line. Each device 306 has
Number of connected calls in class (n₁, ---, n_k) (K is the number of classes)
Device 602 that remembers the acceptable classes when (Fig. 6)
There is. The number of connected calls (n ₁,
---, n_k) Is input, and the comparator 601 outputs (0_,0, ---
From 0) to (n₁, ---, n_k) Rows of devices 602 that match
Is searched for, and the line, that is, the number of connected calls (n₁, ---, n_k)
Acceptable class for as input to comparator 603
Output.

In the comparator 603, the acceptable class is compared with the class of the connection request call input from the device 304, and if the class is included, the acceptability is transferred to the signal transmitting device 307. . If the signal transmitting device 307 can accept the connection request 202 to the next stage, or the acceptable signal 2
03 and the call signal 204 are transmitted through the signal line 309. If it is not possible, the former switch or terminal is notified of the failure. Further, when the call is accepted, the class of the call accepted from the device 304 is notified to the device 305, and the device 501 increments only the number of connected calls of the class. When opened, the device 502 subtracts one.

Next, a second embodiment will be shown. FIG. 7 is a block diagram of an embodiment relating to a call admission control device,
It is equipped with 103,104. The control device is connected to the pre-stage exchange (or terminal) and the post-stage exchange (or terminal) through preset signal lines (signal VCs) 708 and 709 separately from the call (VC) for which acceptance is to be determined. The connection requests 201 and 202 are sent to the in-switch call admission control device via the signal line 708, and the receiving device 702 receives the connection request. The upper and lower VC band information (A, B) included in the connection request signal is stored in the storage device 703.

In this embodiment, for the upstream VC,
Depends on whether the downlink VC band exceeds the threshold B '.
Therefore, for the downlink VC, the uplink VC band has a threshold value A '.
Bandwidth reservations and reservations are made in each direction depending on whether or not the limit is exceeded.
I don't understand. In the following, A ₀, B₀Is the bandwidth reserve
It is a constant related to. In device 705 (FIG. 8), device 70
3, the size of the upstream VC band input by 3 and the device 801
Constant A stored in₀The larger value of
To derive.

On the other hand, the downlink VC input by the device 703
The band B and the constant B ′ stored in the device 804 are compared in the comparator 803. As a result, if B'is larger, the device
The remaining band X of the upstream VP stored in 706 and the output of the device 802 are compared by the comparator 805, and if X is large, 1 is output to the device 806. With the comparison result of the comparator 803,
If B ′ is smaller, X is compared with the upstream VC band A input from the device 703 in the comparator 805, and if X is larger, 1 is output to the device 806.

The larger value of the downlink VC band B input from the device 703 and the constant B ₀ stored in the device 807 is used as the device 80.
Derived in 8. Upward VC input from device 703
The band A and the constant A ′ stored in the device 810 are compared by the comparator 809. As a result, if A ′ is larger, the device 706
The remaining band Y of the downlink VP stored in the above is compared with the output of the device 808 by the comparator 811 and 1 is output if Y is large and 0 is output to the device 806 if Y is small. If A'is smaller than the comparison result of the comparator 809, Y is compared with the down VC band B input from the device 703 in the comparator 811. If Y is large, 1 is output and 0 is output to the device 806.

The device 806 inputs the results of the comparators 805 and 811 and outputs the logical product result to the device 707. Signal transmitter 70
When 7 is acceptable, it transmits a connection request 202 to the next stage or an acceptable signal 203 and a calling signal 204 through a signal line 709. If it is not possible, the former switch or terminal is notified of the failure. Further, when the VCs in the upper and lower bands (A, B) are acceptable, the upper and lower VPs stored in the device 706 are stored in the device 704.
Remaining band (X, Y) of the device is updated to (X-A, Y-B)
Hold on to 706. Conversely, when opened, (X, Y) is changed to (X +
A, Y + B) and hold in the device 706.

[0018]

In the call admission control device of the present invention, since it is possible to consider the downlink VC band and the condition of the downlink VP when determining the admission of the upstream VC, and the band of the VC and the condition of the uplink VC when determining the admission of the downlink VC, The admission control method (particularly the bandwidth reservation method) that improves the overall usage efficiency of the VP has become possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a communication system forming an ATM network.

FIG. 2 is a diagram showing a case when information is transferred in an ATM network.

FIG. 3 is a block diagram showing a first embodiment of the present invention.

FIG. 4 is a block diagram of a class identification device.

FIG. 5 is a block diagram of a call number storage device for each class.

FIG. 6 is a block diagram of an acceptance determination device.

FIG. 7 is a block diagram showing a second embodiment of the present invention.

FIG. 8 is a block diagram of an acceptance / rejection determination device.

[Explanation of symbols]

 101,102 User terminal 103,104 Switch 105-110 Virtual path (VP) 111-116 Virtual channel (VC) 201-212 Signal 301,701 Call admission control device 302,702 Signal receiving device 302,703 Vertical VC band storage device 304 Class specific device 305 Class-specific call number storage Device 306,705 Acceptability determination device 307,707 Signal transmission device 308,309,708,709 Signal line 704 Remaining band updating device 706 Upper and lower VC remaining band storage device

Claims (2)

[Claims] 1. A call admission control device for an ATM exchange in an ATM (asynchronous transfer mode) network that provides communication in a plurality of bands, and a device for receiving and storing band information of upper and lower VCs (virtual channels) constituting a call. And the VP in which the VC is accommodated from the upper and lower VC band information.
A device for identifying the band class of the call in the (virtual path), and the number of calls (n ₁ , ---, n _k ) (k: class) of each band class already accepted by the upper and lower VP pairs so far. And a device for storing the number of calls), when a call of the bandwidth class i makes an admission request to the pair of upper and lower VPs, a predetermined calculation is performed based on the information stored in the device for storing the number of calls, A call admission control device, comprising: a device for deciding whether or not to admit to a pair. 2. A call admission control device for an ATM exchange in an ATM network which provides communication of a plurality of bands, a device for receiving and storing band information of upper and lower VCs constituting a call, and a device for receiving and storing the band information of the upper and lower VPs. A device that stores each remaining band of the upper and lower VPs that are not used by a call that is accepted by the pair, and a device that stores the VC band information when a call of band class i makes an admission request to the upper and lower VP pairs. A call admission control device, comprising: a device for performing a predetermined operation based on information stored in a device for storing a VP remaining band; and a device for deciding whether or not to admit to the VP pair.