JPH04189048A - Quality class control system in atm exchange - Google Patents

Abstract

PURPOSE:To improve the traffic control by setting a line of a channel and reading a data based on the service in which quality classes are provided, with respect to the priority of a class. CONSTITUTION:After a quality class is received by a call control reception control section of a call processing unit 25, the call processing unit 25 implements the control such that a tag representing a path taking a route with high priority and a VCI after conversion are set to an address corresponding to the VCI in a VCI conversion table 210. When information of high priority service is inputted, the information is sent to a high priority SRM 221, an SRM 223 calls a cell to be outputted with priority and an SRM with low priority is selected and the cell is called sequentially.

Description

[Detailed Description of the Invention] [Summary] An ATM equipped with a VCI converter that instructs the route of a call path and a multistage self-routing call path configured with a multistage switch.
Regarding the exchange.

The object of the present invention is to provide a quality class control method for an ATM switch that can guarantee priority in swift operation within the switch according to the quality class of the cell.

When distributing the intermediate stage swift cells from the input stage swift of a multi-stage self-routing channel.

Cells held by the intermediate switches corresponding to the seven quality classes that are input to the intermediate link t corresponding to the quality class are taken out at the output stage in order according to the priority of the quality class.

INDUSTRIAL APPLICATION FIELD The present invention relates to an ATM exchange equipped with a VCI converter for instructing the route of a communication path and a multi-stage self-routing communication path composed of multi-stage switches.

Wideband 15DN as a communication provider for the next household that integrates all communication services such as voice, data, video, etc.
is being researched and developed. ATM
ous Transfer Mode) converts all continuous information such as moving images and burst information such as data into fixed-length packets called cells, without depending on the generation status or communication speed of each.

This is a high-speed transfer technology.

However, in ATV, when burst information is multiplexed, the information increases instantaneously due to the influence of the burst, and exceeds the capacity of the transmission line. the result.

The amount of information that exceeds the capacity of the transmission line cannot be stored in the buffer of the exchange, and information is discarded, which is called cell discard. Furthermore, buffering is performed within the ATM switch for cell exchange, but if there is a difference in buffering time, a delay occurs in the arrival of cells on the receiving side.

For this reason, the quality of services such as data services that are more susceptible to cell discard due to delays, services that are more susceptible to delays than cell discards such as video communication services, and services that are more severe to both discards and delays such as voice communication services, etc. You will need cells that correspond to the class.

[Prior Art 1] In conventional ATM switching equipment, cells that cannot fit in the buffer in the communication path of the switching equipment because they exceed the buffer capacity are naturally discarded due to the superposition of burst-like trough ink.

Since cells overflowing from the buffer are naturally discarded, there is a possibility that calls that are difficult to discard, such as those for data services, may also be discarded.

Part 6 shows an example of the configuration of a conventional ATM switch.

The configuration of this ATM switch is an example in which a multi-stage self-routing channel 62 is used. In Figure 6, 60 is V
CI (Virtual Channel Iden)
tifier) conversion unit (VCC), 61 is a table, 6
2 is a multi-stage self-routing channel (MSSR:
Multi-3tage 5elf Routing
63 is a self-routing module (S RM network) that constitutes the first stage switching section.
: 5elf Routing Module),
64 is a buffer provided for each path within the switch, and 65 and 66 are second and third stage self-routing modules (SRM), respectively.

When the cell goes from the human-powered highway to the human-powered highway, VC! Conversion section 6
At 0, the table 61 is referenced according to the VCI value contained in the data, and the corresponding contents in the table are read. This includes the converted VCI value and route information within the communication path (referred to as a tag). converted v
When the tag along with the Cr value is input to the multi-stage self-routing channel 62, in the SRM 63, which is the first stage swift, it is temporarily stored in a buffer connected to a link determined according to the tag, and when it is read from the buffer 64, it is connected via the link. Power is applied to one of the second stage SRM65s.

Similarly, in the second and third stages, the data is output via a buffer and along the route specified by the tag, and the output in Figure 6 is connected to the output highway, and a cell with the converted vCI value is output. .

As mentioned in point 2, ATV exchange calls are buffered or multi-staged, so when the buffering time is long, services that are sensitive to delays, such as video communication services, can cause significant delays on the receiving side. was there.

[Problems to be Solved by the Invention] Since the above-mentioned conventional ATM switch is equipped with multiple tiers of calls, when the buffering time is long, delays in video communication services, etc. are severe. The service sometimes caused significant delays on the receiving end. and,
Conventional ATM services (voice, data 1 video, etc.)
This creates the problem that cells for any service are uniformly replaced, regardless of the quality class that corresponds to the discards and delays required for the service, which can result in significant delays for delay-sensitive services. Ta.

The present invention is an ATM that can guarantee priority in switching operations within an exchange according to the quality class of cells.
The purpose is to provide a quality class control method for switching equipment.

[Means to solve the problem] FIG. 1 shows the basic configuration of the present invention.

In FIG. 1, 110 is an input cell, 11 is a ■CI conversion unit, 12 is a VCI identification means, 13 is a conversion table, 14 is a route information addition means, 15 is a multi-stage self-routing channel, and 16 is a plurality of (n pieces) Input stage switch provided, 1
7 is a plurality of intermediate stage switches, 18 is a plurality of output stage switches, and 19 is a control unit that accepts call settings and sets a conversion table.

The present invention uses quality class information at the time of call setup.

The route information passing through the intermediate stage corresponding to the quality class of the call is set in the conversion table of the VCI conversion unit, and when a cell is input, the conversion table is referred to based on the VCI value,
The route information corresponding to the VCI set in the conversion table is retrieved, the route information and cells are input into the multi-stage self-routing channel, and the highest stage selects the cells of the middle stage switch with higher quality class priority than that. Cells of middle-stage switches in quality classes with lower priority are read out preferentially.

[Operation 1] The control unit 19 in FIG. 1 converts the conversion value of the VCI assigned to the call requested by the subscriber and the route information corresponding to the quality class based on the call setting information in advance into the conversion table of the CI conversion unit 11. Set to 13.

The cell 10 input from the input highway has V in the header section.
Contains CI. When this cell is manually input to the VCI converter 11, the VCI value included in the cell's header is identified by the VCI identifying means 12.

When the conversion table 13 is referred to using the identified VCI, the set route information and the converted VCI value are extracted, the converted VCI is set at the original VCI position within the cell, and the route information adding means 14 adds a route to the input cell. Information is added and output to the multi-stage self-routing channel 15.

Each link of the input stage switch 16 and the intermediate stage switch 17 among the multistage switches 16 to 18 constituting the multistage self-routing channel 15 is such that each input cell is associated with a quality class. The link connecting to the second switch carries cells of quality class l, and the link connecting to the second switch carries cells of quality class 2.
), the link connecting to the nth switch has quality class n
The quality class corresponding route information of the conversion table 13 is set as follows. Note that if the number of one quality class is less than the number of intermediate links, multiple links are assigned as routes of the same quality class.

Each output stage switch 18 connected to each output highway has two
Cells are taken out from intermediate stage switches 17 corresponding to the priority order.

When changing the priority level (quality class) of each of the plurality of intermediate switches 17, it is executed by rewriting the contents of the conversion table 13 from the control unit 19.

[Embodiment 1] FIG. 2 is a block diagram of an ATM exchange in which the present invention is implemented, and FIG. 3 is a diagram showing a specific operational example of the embodiment.

FIG. 4 is a diagram showing the configuration and control flow of buffer reading, and FIG. 5 is an example of the configuration of a multi-stage self-routing channel.

In the second section, 20 is a multiplexing device, 21 is a C1 converter (VCC), 22 is a multi-stage multi-stage self-routing channel, 23 is a signal processing device, and 24 is a channel control device 125 is a call processing device.

Cells from a plurality of subscribers are input to the multiplexing device 20 and multiplexed therein. VCC21 is a VCI conversion table (T
BL) 210, route information (referred to as a tag) according to the quality class as shown in Fig. 1, and a converted VCI.
The value is stored.

The multi-stage multi-stage self-routing channel 22 includes three stages of self-routing modules (indicated by SRM).

220 to 223 (corresponding to the switches at each stage in FIG. 1) are provided. This VCI conversion table TB L 21
0 is a call handling bag! The setting is performed by the control when 25 accepts a call. The signal processing device 23 inputs and outputs call setting information (setup) sent from a subscriber when making a call, and control cells for disconnection and the like.

When a request is sent to the call processing device 25, a control signal such as a response is returned. The communication path control bag W24 is controlled by the call processing device 25 to control the entire multi-stage self-routing communication path 22, and also detects the switch state of one communication path and notifies the call processing device 25.

The overall operation will be explained using a specific example of the operation of the embodiment shown in FIG.

In the example of FIG. 3, the VCI conversion table 210 provided in the VCI conversion unit 21 stores the tag (route information) and converted VCI corresponding to VC1 as shown in FIG. If the VCI value of a high-priority cell with a high quality class is a, the converted VCI is "x" and the tags are rk, j, i
It consists of three values of J. These three values are: "i" is the link number on the output side of the first-stage module (corresponding to the number of the second-stage module), and "j" is the link number on the output side of the second-stage module. (corresponding to the number of the third-stage module), where "k" represents the number of the output highway on the exit side of the third-stage module.

Similarly, in this example, the low-priority cell (VCI stands for 'rb') is changed to c7) VC1 'T:, 9g is']
, m, n''.

(7) VCI conversion table 21 CJ(D, VC
The contents of "ra of I" are set as follows. Namely.

Call control reception for the call processing device 25 is performed by the control unit.

When receiving a quality class (high priority class in this case) as call setup information from a terminal, the ver is set for that call and the corresponding v is sent from the call processing device (25 in Figure 2).
For the Cr conversion table, a tag representing a route passing through the high priority route i and the converted V are added to the address corresponding to the VCT.
Control is performed to set "CTrx". Similarly, 9 quality class is the low priority class to the address of vCI "a".

A tag passing through intermediate link n, which is a low priority route, and a converted VCI r)'J are both set.

To explain the operation, when a cell a containing information on a high-priority service is input, it looks at the address a of the ver conversion table 2IO, adds -J-i as a tag to the exchange route, and connects the multi-stage self-routing channel 22. send to Within the communication path, the signal is sent to the second-stage high-priority SRM 22+ via a buffer directed to the priority route of the first-stage SRM 220, and is input to the sofa connected to link J.

Next, the third-stage SRM 223 calls cells to be output to the output highway route from a plurality of second-stage SRMs, but at this time, if there are cells in the buffer of the high-priority SRM 221, this is given priority and is called. Thereafter, the SRMs of the same level with lower priority are sequentially called.

In the case of a low-priority cell (VCI is b), ']-m-nl is added as a tag by the VCI conversion table, and as shown in the figure, it is input to the second-stage low-priority SRM 222, and the output highway j therein is It is stored in a connected buffer, and is output after a low priority call is made to the output highway 1 of the third stage SRM 223.

The configuration and control flow of buffer reading will be explained with reference to FIG. The configuration shown in A in the figure is the second stage (middle stage) S.
This configuration is for preferential reading from a plurality of buffers connected to the same output highway of the RM. A. By smell.
The call selector by priority (distributes by tag) 40 is as follows:
Two tags provided in the first stage SRM allocate cells to the upstream buffer. 2nd tier S set up by priority
From the RM (corresponding to sofas 0 to 2), the control unit 41 calls cells in order of priority, and selects the highest priority S.
A cell is called from the RM (buffer 0), a cell is called from the 9th priority SRM (buffer 1), and a cell is called from the low priority SRM (buffer 2).

The control flow performed by this control unit 41 is shown in Part 4, B. If there is a cell, priority is given to buffer 0, it is read out, and when there are no cells in buffer 1, reading of the cell in buffer 1 is started. When the cells in Buffer O and Buffer 1 are exhausted, cells in Buffer 2 are read out.
It is sent to the third stage SRM. This prevents discarding and delaying high priority cells.

FIG. 5 shows an example of the configuration of a multi-stage self-routing channel.

This example has a 210-person capacity highway and a 10-output highway, and is composed of a 3-stage SRM, with 9 quality classes and 5 second-stage SRMs, so 5 classes can be established as shown in the figure. I can do it. In addition, if there are three quality classes in this configuration, 1, for example, 1 in the 12th stage.
The th (top) SRM is class 1. The 2nd and 3rd SRM are class 2. The 4th and 5th SRM are class 3.
It can be assigned as follows.

[Effects of the Invention] According to the present invention, the quality of service corresponding to one quality class can be achieved by setting and reading the communication route for services provided with quality classes in an ATM exchange according to the priority of the class. can be guaranteed. Also, V
The priority order (quality class) can be freely changed by manipulating the CI conversion table. Furthermore, by performing such control, the performance of trough ink control of the ATM switch can be improved.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 is a configuration diagram of an ATM switch in which the present invention is implemented, FIG. 3 is a diagram showing a specific example of the operation of the embodiment, and FIG. FIG. 5 shows an example of the configuration of a multi-stage self-routing channel, and FIG. 6 shows an example of the configuration of a conventional ATM switch. In Figure 1. 10: Input cell 11: VCI conversion unit 12: VCI identification means 13: Conversion table 14: Route information addition means 15: Multi-stage self-routing communication path 16 Two-person stage switch 17: Intermediate stage switch 18: Output stage switch 19: Control Part excretion (

Claims (4)

[Claims] (1) In an ATM switch equipped with a VCI converter that instructs the route of a call path and a multi-stage self-routing call path made up of multi-stage switches, cells are distributed from the input stage switch of the multi-stage self-routing call path to the intermediate stage switch. A characterized in that when the cells are input to the intermediate link corresponding to the quality class and held by each intermediate stage switch corresponding to the quality class, the cells are taken out at the output stage in order according to the priority of the quality class.
Quality class control method in TM switch. (2) In claim (1), the VCI conversion unit includes a conversion table in which routing information including information specifying an intermediate switch corresponding to a quality class is set, and the routing information of the conversion table is configured to include call setting. The VCI conversion unit extracts the routing information from the conversion table using the VCI value of the input cell, and converts the converted VC
A quality class control system in an ATM switch, characterized in that a cell having an I value is added with the route information and input into a multi-stage self-routing channel. (3) According to claim (2), when the output stage switch takes out cells from a plurality of intermediate stage switches corresponding to the priority, the cells are taken out in the switch order according to the priority. Class control method. (4) The ATM exchange according to claim (2), wherein the priority assigned to each switch in the intermediate stage is set by changing the contents of a conversion table of the VCI conversion unit from a control unit. Quality class control method in.