KR100726585B1 - A Grant processing method for ONU in ATM-PON - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to an approval processing method in an optical subscriber connection device of an asynchronous transmission mode-passive optical branch network and a computer-readable recording medium having recorded thereon a program for realizing the method.

2. The technical problem to be solved by the invention

The present invention, in the asynchronous transmission mode-passive optical branch network (ATM-PON) to analyze the approval field of the downlink physical layer OAM (PLOAM) cell for the operation of the ranging protocol and dynamic band allocation cell required upstream at the correct time To provide a computer-readable recording medium recording the approval processing method in the optical subscriber access unit (ONU) to enable the transmission and the program for realizing the method.

3. Summary of Solution to Invention

The present invention relates to an approval processing method in an optical subscriber access device (ONU) applied to an asynchronous transmission mode-passive optical splitter network (ATM-PON), the approval processor in a transmission convergence layer function module provided in the optical subscriber access device. A first step of interpreting an acknowledgment field of a downlink PLOAM cell for operation of a ranging protocol and dynamic band allocation; And a second step of transmitting a corresponding cell requesting upward at an accurate time according to the interpreted approval field value.

4. Important uses of the invention                 

The present invention is used in asynchronous transmission mode-passive optical branch network.

Asynchronous transfer mode-passive optical branch network, OLT, ONU, PLOAM, acknowledgment, ranging cell, register

Description

Asynchronous processing mode-A Grant processing method for ONU in ATM-PON}             

1 is a schematic diagram of an ATM-PON system in general G.983.1.

2 is a structure diagram of uplink frame and downlink frame of a typical ATM-PON.

3 is a diagram illustrating an embodiment of an ONU transmission convergence layer function unit including an admission processor according to the present invention;

Figure 4 is a procedure for the ranging process in the approval processing method according to the present invention.

5 is a structural diagram showing a ranging status register in an admission processing method according to the present invention;

Figure 6 is an embodiment explanatory drawing of the approval processing method in the optical subscriber connection device according to the present invention.

The present invention records an approval processing method in an optical network unit (ONU) of an asynchronous transfer mode-passive optical network (ATM-PON) and a program for realizing the method. The present invention relates to a computer-readable recording medium. In particular, an optical line termination (OLT) and an optical subscriber access unit (ONU) can be connected using passive optical elements, and multiple ONUs can share a single optical fiber. The present invention relates to a method for processing authorization in an ONU of an ATM-PON and a computer-readable recording medium having recorded thereon a program for realizing the method.

1 is a configuration diagram of an ATM-PON system in general G.983.1, and is composed of an OLT, an ONU, and an optical distribution network (ODN). PON is an optical network with no added electronics or optoelectronics. Because ODN is a passive device, the PON is named because it does not require power supply and is not affected by power defects, is not sensitive to electromagnetic interference, and has low maintenance costs. There is this.

FIG. 2 is a frame structure of uplink and downlink of a typical ATM-PON. The downlink frame includes two physical layer OAM (PLOAM) cells in 56 slots in 155 Mbit / s, and 8 in 224 slots in 622 Mbit / s. Contains PLOAM cells. PLOAM cells are inserted every 28 timeslots. Each PLOAM cell is populated with 27 grants. For upstream traffic access, the ONU interprets these grants and sends the cells upwards. The uplink frame consists of 53 cells, so 53 grants are mapped to the two PLOAMs of the downlink frame. All 53 grants are valid grants, and the last grant in the second PLOAM cell is filled with an idle grant. If asymmetric (downward 622.08 Mbits / s), it contains eight PLOAM cells per frame, and the remaining six PLOAM cells are filled with an invalid acknowledgment and are not used in the ONU.

Two key functions are required for ATM-PON to work properly: ranging and MAC. Due to the nature of ATM-PON, which has a tree structure, the downstream stream is broadcast. However, since the upstream stream uses time division multiplexing, the upstream cell may overlap or partially overlap the ODN. do. This collision propagates up to the OLT, which not only prevents the OLT from detecting the correct bit stream, but also causes cell loss. In order to solve this drawback, a technique that requires the ONUs to be virtually equidistantly required is called ranging.

That is, the gist of the ranging protocol is that one OLT provides a different equalization delay ( T _d ) to each ONU in order to keep the equalized round trip delay ( T _eqd ) constant. The purpose. The MAC protocol is a technology that dynamically provides various bandwidths required by multiple ONUs.

Operation and dynamic band allocation of the ranging protocol described above are performed through the grant field of the downlink PLOAM cell. To this end, in accordance with the OLT approval assignment, the ONU must have the ability to interpret the approval field in the PLOAM cell and transmit the cell requesting upwards at the correct time. As a result, in order to transmit cells (data, PLOAM, ranging, mini-slot) upward from the ONU, it is essential to implement a sophisticated and simple implementation so as not to collide with other ONUs. have. However, the proper method has not been implemented yet, which is an obstacle to the implementation of the ATM-PON system.

The present invention has been proposed in order to solve the above problems, and the downlink physical layer OAM (PLOAM) cell for the dynamic bandwidth allocation and operation of the ranging protocol in the asynchronous transmission mode- passive optical branch network (ATM-PON) The present invention provides a method of processing approval in an optical subscriber interface (ONU) that allows the transmission of cells that are requested upwards at an accurate time by interpreting the approval field, and a computer-readable recording medium recording a program for realizing the method. The purpose is.

The present invention for achieving the above object, in the approval processing method in the optical subscriber connection device (ONU) applied to the asynchronous transmission mode-passive optical branch network (ATM-PON), the transmission convergence provided in the optical subscriber connection device A first step of placing a grant processor in the layer function module to interpret the grant field of the downlink Physical Layer OAM (PLOAM) cell for operation of the ranging protocol and dynamic band allocation; And a second step of transmitting a corresponding cell requesting upward at an accurate time according to the interpreted approval field value.

In addition, the present invention, in the asynchronous transmission mode-passive optical splitter network having a processor, an approval processor in the transmission convergence layer function module provided in the optical subscriber connection device, the downlink PLOAM for the operation of the ranging protocol and dynamic bandwidth allocation (Physical Layer OAM) a first function of interpreting an approval field of a cell; And a computer readable recording medium having recorded thereon a program for realizing a second function of transmitting a corresponding cell upwardly requested at an accurate time, according to the interpreted approval field value.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a diagram illustrating an embodiment of an ONU transmission convergence layer function unit including an admission processor according to the present invention.

As shown in FIG. 3, the function of the grant processor roughly interprets the contents of the grant field of the PLOAM cell and transmits the cell upward.

In describing the operation of the transmission convergence layer module of the ONU, the ONU receiver performs the following operation when the downlink frame signal configured by the OLT arrives at the ONU and is subjected to photoelectric conversion, and then transmits a serial data signal.

First, STP parallelizes the serial data, and the synchronization circuit performs the synchronization task for cell division according to the algorithm described in I.432.1, and then acquires PLOAM cell synchronization and frame synchronization. After desynchronization synchronization is performed, BIP processing is performed, and finally, a demultiplexer (DEMUX) delimits PLOAM cells, data cells, and idle cells according to a value of a header and places them in a corresponding buffer. The Alarm register records information on cell synchronization, PLOAM synchronization, and frame synchronization from the synchronization circuit. The PLOAM cell processor operates simultaneously with the occurrence of a signal that the PLOAM cell is stored in the buffer. The PLOAM cell processor processes the sync field, grant field, and message field. In particular, the grant field performs error checking to grant the processor. To read).

Next, looking at the operation of the ONU transmitter, the uplink frame is composed of 53 timeslots having a length of 56 bytes. The timeslot at this time is configured according to the approval provided by the OLT. Thus, this timeslot may be a ranging cell, a PLOAM cell, a minislot, or a data cell. These cells cannot be sent out at any time and are delivered to timeslots specified by the OLT's approval. This function is responsible for the approval handler to open the buffer at the designated time. The PMR (PLOAM, Minislot, Ranging) cell generator is largely responsible for generating PLOAM cells, ranging cells, and mini-slot cells.

Here, the MUX provides a multiplexing function so that a corresponding cell is delivered according to the type of approval. The cell calculates the BIP through a HEC (Header Error Control) field generator. Once the BIP calculation is complete, cell blending is performed in the manner defined in G.983.1, which does not include blending for the header 3 bytes, but only for 53-byte cells. Up to this stage, the cells are processed in parallel, and the mixed cells are converted into serial data and transmitted. The status register records and manages all status information related to ranging.

Hereinafter, the ranging procedure of the present invention will be described to explain the ONU approval processing method according to the present invention.

4 is a flowchart illustrating a ranging process in the approval processing method according to the present invention. When the ONU is first powered on, various initialization operations occur. The process includes recording the serial number and initializing an 8-bit Ranging Status Register (RSR) as shown in FIG. Initially, the RSR has a value of 0x00. RSR ₀ means "Ranging Ready", RSR ₁ means "Grant Allocated", RSR ₂ means "Measurement Completed", RSR ₃ means "Divided slot grant Configured", and the use of the remaining bits is reserved.

That is, as shown in FIG. 4, when an upstream_overhead message arrives from the OLT, the contents of the header 3 bytes are recorded, and if the pre-allocation delay, T _e If there is a value, note the delay value. The delay values are recorded in the Bit Delay Register (BDR), the Byte Delay Counter (BDC), and the Cell Delay Register (CDR).

Here, BDR and BDC are used to provide pre-allocation delay or equalization delay. The former is involved in bit delay and the latter is involved in byte delay. In addition, the CDRs provide up-cell delay. When ONU transmits a cell upward, BDC is implemented before PTS (Parallel To Serial) and operates based on the byte clock, and thus cannot provide accurate bit delay. To precisely provide the bit delay, the bit delay is provided by referring to the value of the BDR when operating in series after the PTS. Until then, the value of "RSR = 0x00" is maintained.

Next, the message delivered by the OLT is generally a serial_number_mask message. If the mask value in this message matches its serial number, the ONU prepares to respond to the ranging cell, changing RSR = 0x01.

The OLT will then open the window and send the ranging cell downward. Accordingly, the ONU is either instant or T _e It responds with a Serial_number_ONU message. If this response message arrives at OLT successfully without collision, it assigns "PON_ID" to ONU and assigns data acknowledgment value and PLOAM cell acknowledgment value. If these values have been successfully allocated, update RSR = 0x02.

In the next step the OLT equalization delay, that is, T _d Enter the value measurement. If the window is opened and the ONU responds to the PLOAM approval and the equalization delay measurement is successful two or more times, the equalizing delay value is changed through the ranging_time message and updated to RSR = 0x06.

Finally, the OLT is assigned the grant value, offset value, and length of the divided slot through a divided_slot_grant_configuration message. This is updated to the value "RSR = 0x0E".

Hereinafter, the approval processing method in the ONU of the present invention will be described in detail.

6 is an exemplary explanatory diagram of an approval processing method in the optical subscriber connection device according to the present invention.

As shown in Fig. 6, the function of the grant processor reads the acknowledgment every up-cell clock (C'CLK) after frame synchronization and provides an appropriate delay according to its value, followed by batch cells, PLOAM cells, data cells, Or transfer the cells in the minislot buffer to the upstream framer.

In Figure 6 we can see the function of the CDR and BDC. Pre-allocation delay or equalization delay values are converted into CDRs in cell units and BDCs in byte units. The longer the table length of the register (right shift register) to provide a cell delay, the longer the table is required. The shortest distance ONU (0km) requires at least 79 register tables.

When an Upstream_Overhead message is received from the OLT, the byte counter value of the pre-allocation delay value will be set. However, initially, the approval table is not filled, and when "RSR = 0x00", the approval processor does not operate. The acknowledgment handler does not operate until "RSR> 0x00" is met and starts with the first acknowledgment value in the move register. As shown in FIG. 5, when the serial number of the Serial_number_mask message and its serial number match, "RSR = 0x01" is obtained, and then the register table is filled with the approval value read from the PLOAM cell.

When the register table is filled, acknowledgment moves to the right for every up-cell clock (C'CLK). There is a cell-by-cell delay and a byte-by-byte delay before the arriving acknowledgment arrives at the compare register location. The acknowledgment in the compare register is compared simultaneously with the values in the register array. However, as shown in FIG. 6, since all register array values except the ranging grant are initially initialized to the unassigned grant, the grant processor does not operate until the ranging grant is received. If the read value is a ranging grant and "RSR = 0x01", the ranging cell (Serial_number_ONU message) is sent upward after the pre-allocation delay. If this message arrives safely in the OLT, the OLT obtains the serial number of the ONU, and then assigns the "PON_ ID" and then assigns the data cell acknowledgment value (DT_GR) and PLOAM cell acknowledgment value (PO_GR) to be used by the ONU. will be. ONU writes this value to the register array. This assigns RSR = 0x02.

On the other hand, if "RSR> = 0x02" is satisfied, the ONU is in a state capable of transmitting a PLOAM cell and a data cell upward. The OLT will open a window to measure equalization delays and provide PLOAM cell approval to the ONU. Accordingly, the ONU participates in equalization delay measurement by transmitting a PLOAM cell several times. When the time measurement is completed, the OLT allocates equalization delay through a ranging_time message. The ONU writes the equalization delay value to the equalization delay register and updates it to "RSR = 0x06".

At "RSR <= 0x06", minislots cannot be delivered upwards. Finally, the ONU receives the divided_slot_grant_configuration message to assign an offset to the minislot and its location (assign a value to the BDC that sets T _m ). do. This results in RSR = 0x0E.

The method of the present invention as described above may be implemented as a program and stored in a computer-readable recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.).

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

The present invention as described above, in the ONU that performs the function of transmitting a cell requesting upward at the correct time by interpreting the grant field of the downlink PLOAM cell for the operation of the ranging protocol and dynamic band allocation in ATM-PON The present invention relates to an approval processing method. When the approval processing method of the present invention is used, a response corresponding to the status of each of up to 64 ONUs connected to the OLT can be prevented, so that collision between cells can be avoided upward, thereby enabling a stable implementation of the system. It is effective.

Claims (7)

In the approval processing method in the optical subscriber access unit (ONU) applied to the asynchronous transmission mode-passive optical branch network (ATM-PON), A first step of placing an approval processor in a transmission convergence layer function module included in the optical subscriber access device to interpret the approval field of a downlink physical layer omam (PLOAM) cell for operation of a ranging protocol and dynamic band allocation; And A second step of transmitting a corresponding cell requesting upward at an accurate time according to the analyzed approval field value Approval processing method in the optical subscriber connection device comprising a. The method of claim 1, The approval process is, In the transmission convergence layer function module, an approval processor is placed and connected to a PLOAM cell processor and a MUX (Multiplexer) to receive the contents of the approval field from the PLOAM cell processor, and then internally process the ranging cell, the PLOAM cell, and the mini slot. Or a function of opening a corresponding buffer so that a data cell can be located. The method according to claim 1 or 2, The approval process is, In order to perform the ranging procedure, a serial number is recorded and an upstream_overhead message arrives from the OLT, including initializing a predetermined bit of a Ranging Status Register (RSR). The contents of the header 3 bytes are recorded, and if a pre-allocation delay or a Te value exists, the delay value is stored in a bit delay register (BDR), a byte delay counter (BDC), and a cell delay register (BDC). A third step of recording in a CDR: Cell Delay Register; When the serial_number_mask message arrives from the OLT and the value of the mask included in the message matches its serial number, the ONU prepares to respond to the ranging cell and changes the RSR value. Open the window and send the ranging cell downward. Accordingly, the ONU immediately responds with a Serial_number_ONU message immediately or after T _e , and if the response message successfully arrives at the OLT without collision. A fourth step of allocating a "PON_ID" to the ONU and then allocating a data grant value and a PLOAM cell grant value to update the RSR value; After the OLT enters the equalization delay ( T _d ) measurement and the window is opened, if the ONU responds to the ONU in response to the PLOAM approval and succeeds in measuring the equalization delay more than a predetermined number of times, the equalizing delay value is set through a ranging_time message. Changing and updating the RSR value; And A sixth step of allocating an grant value, an offset value, and a length of the divided slot through the divided_slot_grant_configuration message of the OLT and updating the RSR value; Approval processing method in the optical subscriber connection device comprising a. The method according to claim 1 or 2, The approval process is, To record the ranging status register in the ONU, a pre-allocation delay value and an equalization delay value, a bit delay register (BDR), a byte delay counter (BDC), and a cell delay register (CDR) A method for processing approval in an optical subscriber connection device, characterized in that a delay register is used. The method according to claim 1 or 2, The approval process is, After operating according to the ranging status register value with a plurality of shift registers, cell delay registers, byte delay registers, and comparison registers, the ranging cell buffer enable signal, the PLOAM cell buffer enable signal, the data cell buffer enable signal, And a split slot cell buffer enable signal and a non-operation signal. The method according to claim 1 or 2, The approval process is, When the RSR value is "0x00", the authorization processor is not operated and the RSR value is greater than "0x00" to operate the authorization processor. When the authorization value is first entered into the shift register, the serial_number_mask ) If the serial number of the message and its own serial number match, the RSR value becomes “0x01”. From then on, the register table is filled with the acknowledgment value read from the PLOAM cell. If the register table is filled, the upward cell clock (C'CLK) Acknowledgment shifts to the right, undergoes a cell delay and a byte delay until the arriving acknowledgment arrives at the compare register location, and the acknowledgment in the compare register is compared simultaneously with the values in the register array, if the value read is lane If the RACK is acknowledged and the RSR is "0x01", then the ranging cell (Serial_number_ONU message) is sent upward after the pre-allocation delay, and this message is Upon arrival at the OLT, the OLT obtains the serial number of the ONU, assigns the PON_ ID, and then assigns the data cell acknowledgment value "DT_GR" and the PLOAM cell acknowledgment value "PO_GR" to be used by the ONU. Writing the value to the register array results in RSR = 0x02, When the RSR is greater than or equal to "0x02", the ONU is in a state capable of transmitting a PLOAM cell and a data cell upward, and the OLT opens a window to measure equalization delay and grants the ONU a PLOAM cell acknowledgment. Accordingly, the ONU transmits a PLOAM cell several times, thereby participating in equalization delay measurement, and when the time measurement is completed, the OLT allocates the equalization delay through a ranging_time message. Writes an equalization delay value to the equalization delay register and updates the RSR = 0x06, If the RSR is less than or equal to "0x06", the minislot cannot be delivered upwards, and finally, the ONU receives the divided_slot_grant_configuration message to designate an authorization value and a corresponding position for the minislot. A method of processing an approval in an optical subscriber connection device, characterized by assigning an offset to make RSR = 0x0E. In the asynchronous transmission mode-passive optical branch network with a processor, A first function of placing an approval processor in a transmission convergence layer function module included in the optical subscriber access device to interpret an approval field of a downlink physical layer OAM (PLOAM) cell for operation of a ranging protocol and dynamic band allocation; And A second function of transmitting a corresponding cell requesting upward at an accurate time according to the analyzed approval field value A computer-readable recording medium having recorded thereon a program for realizing this.

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