KR20010018830A - Low speed subscriber interface apparatus of atm exchange system - Google Patents

Abstract

PURPOSE: An apparatus for interfacing with low speed subscribers in an ATM switching system is provided to supply selective priorities to physical layer boards, so as to expand service quality to physical layers and to transmit user cells in real time by priority assignments in low speed physical layer boards, to prevent cell loss. CONSTITUTION: A physical layer interface(32) receives various frame signals from a priority multiplexer/demultiplexer, and processes various operation and maintenance signals included in an overhead, then extracts ATM cells to transmit the ATM cells to an ATM layer processor(34). The physical layer interface(32) loads ATM cells received from the ATM layer processor(34) into frames, and configures the frames with the operation and maintenance signals, then transmits the frames to subscribers. If the ATM cells received from the physical layer interface(32) are user cells, the ATM layer processor(34) makes the user cells internal cells added with routing information to transmit the internal cells to a switch link interface(36), and converts the internal cells into the ATM cells to transmit the ATM cells to the physical layer interface(32). If the ATM cells are signal processing cells or OAM(Operation Administration and Maintenance) cells, the signal processing cells or the OAM cells are transmitted to a controller(30). The switch link interface(36) converts the internal cells to transmit the internal cells to a switch network, and converts cells received through a switch link into original types to transmit the cells to the ATM layer processor(34). The controller(30) monitors board states, and informs the ATM layer processor(34) of the board states.

Description

LOW SPEED SUBSCRIBER INTERFACE APPARATUS OF ATM EXCHANGE SYSTEM}

The present invention relates to an asynchronous transfer mode (hereinafter referred to as "ATM") switching system, and more particularly to a low speed subscriber matching device.

In the ATM switching system, the matching module terminates the physical layer of 155 Mbps Synchronous Transfer Module level 1 (STM-1), which is a basic transmission rate of a broadband-integrated services digital network (B-ISDN) as a part for subscriber and relay line matching. The matching module detects the incoming input frame, extracts the ATM cell, adds path selection information in the system, and changes the VPI / VCI (Virtual Path Identifier / Virtual Channel Identifier) of the ATM cell header to transfer to the switch module. Perform. In addition, the cell received from the switch module is carried on the physical frame to transfer the function to the outside. The matching unit performs fast cell processing so most of the functionality is performed in hardware without the aid of a processor.

The subscriber interface of the subscriber matching module matches physical frames of STM-1 (155bps), DS3 (Digital Signal level-3; North America, 44.736Mbps), DS1E (Digital Signal level-1E; European, 2.048Mbps), For DS1E / DS3 User Network Interface (UN) matching, it has cell multiplexing / demultiplexing function for low and medium speed and 155Mbps switch speed matching.

The link connection between the subscriber matching module and the switch module is usually configured to match 1: 1 with the STM-1 basic speed of the subscriber. Therefore, three DS3 or 72 DS1E subscriber (low speed subscriber) links are multiplexed into one switch module link.

Based on the Universal Forum & Operations Physical Layer Interface for ATM (UTOPIA) Level 1 of the ATM forum, user cell transmission at the interface between the physical layer and the ATM layer is basically performed in a round robin manner. The round roving method is a method of transmitting a received cell based on a predetermined order without giving priority to a cell regardless of who the subscriber is in the physical layer.

1 illustrates a physical layer configuration of cell transmission processing in a round roving method. The physical layer includes n physical layer boards 10A, 10B, 10C, ..., 10E and multiplexing and demultiplexers 12 connected to a low speed subscriber link. The multiplexer and demultiplexer 12 is connected to a physical layer interface connected to an ATM processing layer. When the user cell arrives at the n physical layer boards 10A, 10B, 10C, .., 10E, the multiplexing and demultiplexer 12 performs the physical layer boards 10A, 10B, 10C, .., in a round roving manner. 10E) receives the received user cell, multiplexes it and provides it to the physical layer interface unit. In addition, the multiplexer and demultiplexer 12 demultiplexes a cell provided by the physical layer interface unit and provides the same to the physical layer board.

In this round roving cell transmission process, the cell delay time is not a problem when the number of physical layer boards is small, but the delay time is relatively increased as the number of physical layer boards is increased. If the subscriber connected to the physical layer is a national network, for example, real time transmission without time delay should be performed. And even if there is no user cell may need to continue to access. However, if the cell transmission processing is performed in the above round roving method, the quality of service for the subscriber cell required for real time transmission is reduced. In addition, the round roving method also has an inefficiency of inserting and transmitting an idle cell if there is no valid user cell.

Accordingly, an object of the present invention is to provide a subscriber matching device that effectively prevents user cell delay and performs user cell processing in the physical layer.

Another object of the present invention is to provide a subscriber matching device for assigning user priorities in the physical layer.

In accordance with the above object, the present invention provides a plurality of physical layer units connected to a low speed subscriber link in a low speed subscriber matching device in an asynchronous transmission mode switching system, and the physical layer units based on a predetermined selection control. A multiplexing and demultiplexing unit configured to selectively multiplex an asynchronous transmission mode cell and perform the reverse function, and vice versa, an asynchronous transmission mode layer processing unit performing the asynchronous transmission mode layer processing and vice versa, And a control unit for controlling the multiplexing and demultiplexing unit according to a priority control request for each physical layer unit required by an upper control block.

In addition, the present invention stores the priority information for each physical layer according to the priority control request for each physical layer unit requested by the upper control block, and the number of effective asynchronous transmission mode cells received by the asynchronous transmission mode layer processing unit physical layer It further includes a priority and cell count memory for counting and storing each.

1 illustrates a physical layer configuration of cell transmission processing in a round roving scheme.

2 is a diagram illustrating a physical layer configuration according to an embodiment of the present invention for cell transmission processing according to the priority of each physical layer board;

3 is a block diagram illustrating an ATM subscriber matching device controlling to transmit a cell according to a priority of each physical layer board according to an embodiment of the present invention;

4 is a control flowchart performed by the controller of FIG. 3 according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the same elements in the figures are represented by the same numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

2 is a diagram illustrating a physical layer configuration according to an embodiment of the present invention for performing cell transmission processing according to the priority of each physical layer board. Referring to FIG. 2, the physical layer includes n physical layer boards 20A, 20B, 20C, .., 20E and priority multiplexer and demultiplexer 22 connected to a low speed subscriber link. The multiplexer and demultiplexer 22 selects and multiplexes user cells output from the corresponding physical layer boards 20A, 20B, 20C, .., 20E based on the selection signal PSEL according to the priority of each physical layer board. It is provided to the physical layer interface unit 32 of the. In addition, the cells provided by the physical layer interface unit 32 are demultiplexed and provided to the corresponding physical layer board. The selection signal PSEL applied to the multiplexer and demultiplexer 22 is provided by the controller 30 of FIG. 3.

3 is a block diagram of an ATM subscriber matching device that controls cell transmission processing according to the priority of each physical layer board according to an embodiment of the present invention. The control unit 30, the physical layer interface unit 32, and the ATM layer A processing unit 34, a switching link matching unit 36, and a priority and cell count memory 38.

The physical layer interface unit 32 receives various frame signals provided from the priority multiplexer and demultiplexer 22 of FIG. 2, processes various maintenance signals included in the overhead of the frame, extracts an ATM cell, and extracts an ATM cell. It transfers to the layer processing unit 34, and loads the ATM cell received from the ATM layer processing unit 34 in the frame, and configures the frame with the maintenance signal and delivers it to the subscriber.

If the ATM cell received from the physical layer interface unit 32 is a user cell, the ATM layer processing unit 34 transfers the inner cell to the switch link matching unit 36 by making the inner cell to which the routing information is added. The internal cell received from the matching unit 36 is converted into an ATM cell and transferred to the physical layer interface 32. In addition, when the ATM cell received from the physical layer interface unit 32 is a signal processing cell or an OAM (Operation Administration and Maintenance) cell, the ATM cell is transmitted to the control unit 30, and the OAM cell or signal provided by the control unit 20a or 20b. The processing cell is transferred to the physical layer interface 32.

The switch link matching unit 36 converts the internal cells output from the ATM layer processing unit 34 to the switch internal cell format, transfers them to the switch network through the switch link, and transfers the cells received through the switch link to the original format. Is converted to the ATM layer processor 34 and transferred to the ATM layer processor 34. In addition, the internal cell provided by the control unit 30 is multiplexed with the user cell and transmitted to the switch network, and the internal message cell is transmitted to the control unit 30 among the cells received from the switch network.

The controller 30 performs various OAM functions and connection management functions of the subscriber matching device, and communicates with an upper control module through an internal message. In addition, by monitoring the state of the board using the hardware alarm signal to tell the ATM layer processor 34 so that the ATM layer processor 34 performs a function corresponding thereto. In addition, according to an embodiment of the present invention, the control unit 30 selects and controls ATM cells received at each physical layer board 20A, 20B, 20C, .., 20E according to the priority of each physical layer board of FIG. do. That is, the selection signal PSEL according to the priority of each physical layer board 20A, 20B, 20C, ..., 20E is applied to the priority multiplexer and demultiplexer 22. The control operation of the controller 30 according to each physical layer board priority will be described later in more detail with reference to FIG. 4.

The priority and cell count memory 38 of FIG. 3 is connected to the ATM layer processing section 34, and each of the physical layer boards 20A, 20B, 20C, .., 20E in the upper control block (call processing block). The priority information provided by the controller 30 is stored according to the priority assignment request. In addition, the number of valid ATM cells for each physical layer board 20A, 20B, 20C, .., 20E applied to the ATM layer processing unit 34 is counted, and the count value is stored. The count value is provided when the upper control block requests to determine the state of the physical layer board.

Hereinafter, an operation according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 2 to 4. Upon request from the low speed subscriber, the upper control block (call processing block) provides priority information of each physical layer board 20A, 20B, 20C, ..., 20E to the control unit 30 of the subscriber matching device. Accordingly, the control unit 30 receives the priority information in step 100 of FIG. 4, and stores the physical layer board priority information received in step 101 in the priority and cell count memory 38. Prioritization may be applied to all low speed physical layer boards 20A, 20B, 20C, .., 20E in the physical layer, and may be applied to only a few specific low speed physical layer boards as needed. . The remaining physical layer boards to which priority is not given may be applied by a round roving scheme, and the priority may be adjusted according to the received cell count value.

After step 101 of FIG. 4, the control unit 30 prioritizes the multiplexing and demultiplexer 22 of the selection signal PSEL based on the priority and the physical layer board priority stored in the cell count memory 38 as in step 102 of FIG. 4. By applying to the priority multiplexer and demultiplexer 22 selectively receive, multiplex and output the ATM cells of the physical layer board according to the priority. The controller 30 determines whether there is physical layer board information having the same (or no) physical layer board priority in the priority and the cell count memory 38 in step 104, and if there is, the priority and cell count memory ( The selection signal PSEL is applied to the priority multiplexer and demultiplexer 38 based on the cell count value of each physical layer board stored in 38). The priority and cell count memory 38 counts and stores the number of effective ATM cells for each physical layer board 20A, 20B, 20C, .., 20E applied to the ATM layer processor 34 by an internal counter. have.

Accordingly, physical layer boards with the same (or no) priority are also selected. The controller 30 preferably selects a physical layer board having a small cell count value first when the priority is the same (or not). It is efficient in system operation to process the physical layer board with less ATM cell reception first.

In the above description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. In the embodiment of the present invention, the subscriber matching device has been described with reference to specific embodiments, but the present invention can also be applied to a relay line matching device. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the equivalent of claims and claims.

As described above, the present invention can extend the quality of service to the physical layer by providing the selective priority to the physical layer board, and in particular, the user's cell real-time transmission can be performed by the priority assignment in the low speed physical layer board. Losses can also be prevented.

Claims (4)

In a low speed subscriber matching device in an asynchronous transmission mode switching system, A plurality of physical layer portions connected to the low speed subscriber link, A multiplexing and demultiplexing unit configured to selectively multiplex the asynchronous transmission mode cells of the plurality of physical layer units based on a predetermined selection control, and output an vice versa; An asynchronous transmission mode layer processing unit configured to perform asynchronous transmission mode layer processing and vice versa on the multiplexed asynchronous transmission mode cell; And a controller for controlling the multiplexing and demultiplexing unit according to a priority control request for each physical layer unit required by an upper control block. 2. The method of claim 1, wherein priority information for each physical layer is stored according to a priority control request for each physical layer unit required by the upper control block, and the number of valid asynchronous transmission mode cells received by the asynchronous transmission mode layer processor is physically stored. And a priority and cell count memory for counting and storing each layer. The method of claim 1, wherein the controller controls the multiplexing and demultiplexing unit to receive the cells in a round roving manner when the priority control request for each physical layer part is a request for priority control of some physical layer parts. Low speed subscriber matching device. 3. The method of claim 2, wherein, when the priority control request for each physical layer unit has the same physical layer unit priority, the controller determines the priority by using the priority and a cell count value stored in a cell count memory. A low speed subscriber matching device for controlling the multiplexing and demultiplexing unit.