JP2845189B2 - ATM switching network call admission control method and apparatus - Google Patents

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 method and apparatus for each ATM exchange in an ATM exchange network.

[0002]

2. Description of the Related Art Conventionally, every time a call is generated in an ATM exchange, the exchange searches for an empty path and sets a call each time. In addition, as shown in Japanese Unexamined Patent Publication No. 4-179337, the realization of a switch cell buffer is performed. In some cases, the acceptability is determined based on the usage status.

[0003] Further, there is a method in which a search for the presence or absence of an empty path is performed by relaying for each node on a route, or a method in which a connection is established after an end-to-end is secured at a transmission source. In each case, the search for the exchange itself is the basis.

[0004]

SUMMARY OF THE INVENTION The conventional ATM described above.
In the switching network call admission control method, a call is set up by searching for an empty path for each ATM exchange. In this case, information on the use status of the path has been obtained only up to the adjacent node. Therefore, in processing the generated call, there is a problem that it takes time and a large number of signal operations to set up an end-to-end path.

An object of the present invention is to provide an ATM switching network call admission control method and apparatus which can set up a path for an originated call in a short time.

[0006]

In a communication network including a plurality of ATM exchanges, when a new call request is made,
There are two types of call acceptance processing methods. One is a method without a centralized control device, in which each ATM exchange holds path information to a destination and information on the use status of each link on the corresponding path, and based on the information, a free path is used. Is a method of accepting a call by selecting. In this method, the respective ATM exchanges mutually notify each other of the usage status information of the link directly accommodated by each other, and
It must be constantly updated.

Another method is to use a centralized path information control device. In this case, each ATM exchange makes an inquiry to the centralized path information control device when a call request is made, and the bus to the destination is vacant. This is a method of receiving a call after having the user tell us. In this case, each ATM exchange notifies the central control unit of the information each time the use status of the link accommodated by the ATM exchange changes, and makes contact with the path information central control unit every time a call is requested. There must be.

[0008] The ATM switching network call admission control method of the present invention comprises:
A system using a centralized path information management device for call reception processing is employed, and each ATM exchange changes its use status of a link accommodated by itself with respect to a centralized path information control device (hereinafter referred to as a network management device). Each time the information is notified to the network management device, the network management device determines the status of each bus according to the usage rate of each link from the notified usage status information of each link in three levels, that is, level 0: call request. A new call can be accommodated irrespective of conditions, level 1: whether or not it can be accommodated depends on the requirements of the call, and level 2: a new call cannot be accommodated. Notify the ATM exchanges, and in each ATM exchange, when a new call request is made, if there is a path of level 0 among the paths to the destination, without inquiring the network management device. The path Select and accept the call, and if all the paths to the destination are at level 2, reject the call without inquiring the network management device. A call admission control method is characterized in that an inquiry is made to the network management device only when all paths are at level 1.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a method and apparatus for controlling call acceptance of an ATM switching network according to the present invention will be described with reference to the drawings. FIG. 3 is an explanatory diagram showing an example of a network configuration to which the ATM switching network call admission control method of the present invention is applied.

The ATM switching network is composed of a network management device 1, an AT
Each of the ATM exchanges 2 to 4 is connected to a terminal.

FIG. 4 is a block diagram showing a configuration example of ATM exchanges 2 to 4 to which the method of controlling call admission of the ATM exchange network according to the present invention is applied. ATM switch 2-4 and enters line accommodating portion 5 ₁ to 5 _n accommodating the subscriber terminal (hereinafter abbreviated as terminal),
And outgoing line housing part 6 ₁ to 6 _n, a signal processing unit 7, an ATM switch unit 8, and a call admission control unit 9. Line accommodation unit 5 ₁ to 5 _n enters, among the cells coming from the terminal, and has a drop-and-insert capability of the signal processing unit 7 F transferred by way of the internal bus by extracting signal cell. The signal processing unit 7 performs ATM conversion of the signal frame, and the call reception unit 9 receives the signal frame from the signal processing unit 7 and performs the call reception control of the present invention. Outgoing line accommodation unit 6 ₁ to 6 _n each other ATM switches, and are connected to the network management device 1.

FIG. 5 is a block diagram showing the configuration of the network management device 1. The network management device 1 includes a cell receiving unit 11 and a call admission control unit 12. The cell receiving unit 11 has an ATM conversion function, converts the received ATM cell into an information frame, and transfers the information frame to the call admission control unit 12. In the call admission control unit 12,
The call admission control method of the present invention is executed.

Next, the call admission control of the present invention will be described with reference to FIG. FIG. 1A is an explanatory diagram showing the relationship between the usage rate and the usage rate level of each path in the network according to the present invention. THO and THl are threshold values, respectively. If the usage rates of all the links in the path are equal to or lower than THO, the usage level of the bus is set to 1. The above processing is performed in the call admission control unit 12 in the network management device 1.

FIG. 1B shows a flowchart of a path utilization rate notification function of the network management apparatus according to the present invention. Network management device 1
Collects the utilization information of each link to be accommodated from each of the ATM switches 2 to 4 (step 21), calculates the utilization rate (TH) of each path based on the value, and applies the level classification to all the paths. (Step 22) If one or more path utilization levels change, the ATM switch is notified of the change in the bus usage conditions (Steps 23 and 2).
4).

FIG. 2 shows a flow chart of the path setting of the present invention in the ATM exchange. Upon receiving the call setting request from the calling terminal (step 31), the ATM exchange selects a path to the destination (step 32) and checks whether or not each path has a utilization level of 0 (step 33). ). If there is, the bus is selected and a path is set (step 38). If the usage rate level of all the paths is 2 (step 35), the reception of the call is discarded (step 39). Otherwise, a path setting request is made to the network management device (step 36). The network management device determines whether or not the call can be accommodated based on the current use state of each link and the required bandwidth, communication quality, and traffic characteristics of the requested new call. If it can be accommodated, the setting permission is notified to the inquiring ATM exchange (step 37), and the exchange sets the path using the path (step 38). If it cannot be accommodated, the network management device notifies that there is no path corresponding to the ATM switch of the contact origin (step 37), and the ATM exchange is busy accepting the call request. Return and discard (step 39). Also,
Each time a path is set and the link usage rate changes, each A
The TM exchange notifies the changed usage rate of the link to the network management device.

FIG. 6 is a flowchart showing an example of the overall flow. Each of the ATM switches 2 to 4 issues a link utilization notification to the network management device 1 when the utilization of the link accommodated therein changes. The network management device 1
Based on the received link utilization rate notification, the utilization level of each path is checked, and if the utilization level is changed, each ATM exchange is notified of a new utilization level of the changed path. Next, when there is a call request from the terminal, the ATM exchange searches for a path of level 0 on the path to the destination. This example shows a case where there is only a level 1 pass. In this case, if the path can be set, the network management device 1 sends a permission notification to the requesting ATM exchange, and the ATM exchange sets the path.

[Brief description of the drawings]

FIG. 1A is a diagram showing a threshold of a usage rate level of a path in an ATM switching network call admission control method of the present invention. , (B)
9 is a flowchart of a path usage rate notification in the network management device.

FIG. 2 is a flowchart for setting a path in an ATM exchange;

FIG. 3 is a configuration diagram of an ATM switching network to which an ATM switching network call admission control method of the present invention is applied.

FIG. 4 is a block diagram of an ATM switch to which the ATM switching network call admission control method of the present invention is applied.

FIG. 5 is a block diagram of the network management device shown in FIG. 3;

FIG. 6 is a sequence chart of a signal exchange between the ATM exchange and the network management device from a path assignment request to a call setup in the case of the usage rate level 1;

[Explanation of symbols]

1 network management apparatus 2 ATM exchange 3 ATM switching unit 4 ATM exchange 5 ₁ to 5 _n-cored line accommodating portion 6 ₁ to 6 _n outgoing line housing part 7 signal processing section 8 ATM switch unit 9 call reception control unit 11 the cell receiving unit 12 calls Reception control unit

Claims (2)

(57) [Claims] 1. A management system for managing the use status of each link in an ATM network.
Each ATM exchange has its own network management device.
Link usage report to the network management device
The network management device uses the information to determine whether each path can be used.
Information to each ATM exchange in an up-to-date manner.
The exchange, based on this availability information,
In an ATM switching network call admission control method for defining a path search method in a call processing of each ATM switching in an ATM network for determining whether connection processing is possible or not , a network management device provides each ATM switching with an idle for each outgoing route.
The first usage level to display the path and the path allocation required
Request level, indicating a second usage rate level, and line blocking
Applicable among the three levels of indication of the third usage level
And updating presenting levels by route, according to the level ATM switching system corresponds to the calling first
And the third usage level self-processed, the second usage
For the rate level, it is necessary to assign a path to the network
Request, and the network management device receiving the path assignment request maintains the current status.
ATM exchange requested by determining the route by the route table
Instructing the route to the exchange, and the ATM switch receiving the route instruction uses the route to
An ATM switching network call admission control method, comprising a step of performing a call processing . 2. The use status of each link in an ATM network is managed.
Each ATM exchange has its own network management device.
Report the network usage status to the network management device
The network management device uses the information to determine whether each path can be used.
Information to each ATM exchange in an up-to-date manner.
The exchange, based on this availability information,
An ATM switching network call admission control method for defining a path search method in a call processing of each ATM exchange in an ATM network for determining whether connection processing is possible or not , wherein the path availability information indicates a free path. Level, a second usage level indicating a path assignment request instruction, and a third usage level indicating a line blockage.
This is a display of the level, and the ATM exchange side sets the call setting when the required path is an empty path of the first usage rate level.
If the line is blocked at the third usage level, the notification of call rejection is independently processed, and access to the network management device for the path allocation request is made only when the path allocation request instruction is at the second usage level. Characterized by having means for performing
ATM switching network call admission control device to.