JP3636312B2 - OAM processing method and method in ATM - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to OAM processing in ATM (asynchronous transfer mode) including processing related to maintenance / operation (OAM processing). In particular, when OAM processing is performed by ATM cells input via a transmission line, time is required. The present invention relates to an OAM processing method and method in ATM that can provide a margin in OAM processing, improve processing efficiency, and can output cells other than empty cells without changing the input order.
[0002]
[Prior art]
Conventionally, since all cells are input in this type of ATM OAM processing, the partial processing of the OAM processing section is always finished within one cell passage time. When the passage time is exceeded, cells cannot be input on the input side and cells cannot be output on the output side, so all OAM processing must be processed within one cell passage time.
[0003]
For example, as shown in FIG. 5, a user cell, an OAM cell, and an empty cell are input as needed through the transmission path as ATM cells. Since the length of one ATM cell is defined, the transit time of one ATM cell is fixed depending on the transmission speed of the transmission path. However, the time required for these OAM processes exceeds this transit time. In the illustrated example, each cell can be in the range of approximately 60% to 90% with respect to the transit time of one ATM cell, but the second and sixth cells exceed 100%.
[0004]
In such a case, the OAM processing unit requires high-speed processing for increasing the clock speed or an increase in the number of processor cores, and thus the possibility of causing an increase in hardware scale is inevitable.
[0005]
For example, as shown in FIG. 6, the OAM processing unit that has received an ATM cell (procedure S11) divides the ATM cell into N (procedure S12) so that it can be processed within one ATM cell passage time, and N After the cell processing is performed by N processor cores within one cell passage time (step S13), the ATM cell is transmitted to the outside (step S14). That is, it is necessary to increase the number of processor cores.
[0006]
A proposal for solving this is disclosed in, for example, Japanese Patent Laid-Open No. 11-32046. In this time division OAM processing method in ATM, processing cannot be performed within one cell passage time, but for OAM processing that should be processed within a larger predetermined time, tasks are divided so that processing can be performed within one cell passage time. , N cells including user cells and empty cells are set as one cycle, and time division processing is performed within the N cell passage time. Therefore, an increase in the number of processor cores can be avoided by dividing the number of steps into one processor core that can be processed within one cell passage time.
[0007]
This proposal requires a division of processing for a task that is always processed in common regardless of the type of ATM cell and that cannot be processed within the passage time of one cell. Because of this N-step serial processing, cell sequence number management and delay due to the processing are inevitable. Since these are also executed for user cells or empty cells that can be processed within one cell passage time, reduction in processing efficiency is inevitable.
[0008]
As means for solving this problem, for example, there is an OAM processing apparatus disclosed in Japanese Patent Laid-Open No. 2000-236333. In this OAM processing apparatus, a processor is connected to each of a plurality of cell buffers arranged in parallel, and a memory for managing a processing state corresponding to each cell is provided. Based on the data in the memory, the cell is read from and written to the cell buffer. In this case, the cell buffer stores the remaining cells in which empty cells to be input are discarded.
[0009]
[Problems to be solved by the invention]
The conventional ATM OAM processing method or apparatus described above has the following problems.
[0010]
The problem of the method disclosed in Japanese Patent Application Laid-Open No. 11-32046 is that, as described above, delay due to processing and reduction in processing efficiency are inevitable.
[0011]
The reason is that the management of sequence numbers is necessary for ATM cell division, and the empty cells are processed in the same manner as other cells.
[0012]
The problem of the device disclosed in Japanese Patent Laid-Open No. 2000-236333 is that the output order of ATM cells is different from the input order.
[0013]
The reason is that the data is read from the processed cell and output based on the data in the memory that manages the processing state.
[0014]
An object of the present invention is to solve such problems, and to provide an OAM processing method and method in ATM capable of improving processing efficiency and outputting cells other than empty cells in the input order.
[0015]
[Means for Solving the Problems]
An OAM processing method in ATM according to the present invention is an OAM processing method in ATM (Asynchronous Transfer Mode) including processing (OAM processing) related to maintenance / operation, and discards empty cells from received cells and removes cells excluding empty cells. It is characterized by performing partial processing at fixed time intervals by a pipeline method and outputting cells in the order of processing. Further, when one cell passage time is exceeded during the partial processing, an empty cell is inserted and output.
[0016]
The processing efficiency can be improved by discarding the empty cells, and the output order can be adjusted by adopting the pipeline system.
[0017]
Specific procedures include a discarding procedure for discarding empty cells from received cells, a processing procedure for performing partial processing for each fixed time by a pipeline method for cells excluding empty cells, and for each cell passing time. In this case, the method includes an insertion procedure for outputting a processed cell while inserting a blank cell when there is no processed cell. Here, the fixed time is preferably the one cell passing time.
[0018]
The OAM processing method in ATM according to the present invention is an OAM processing method in ATM (Asynchronous Transfer Mode) including processing (OAM processing) related to maintenance and operation, and a separation unit that separates an empty cell from a received cell; A processing unit that receives cells to be removed and performs partial processing at fixed times by the pipeline method, receives a processed cell from the processing unit, outputs it to the outside, and inserts an empty cell when there is no corresponding transmission cell And an insertion portion.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0020]
FIG. 1 is a functional block diagram showing an embodiment of the present invention.
[0021]
In the OAM processing method in the ATM shown in FIG. 1, an empty cell separation unit 1, an OAM processing unit 2, an empty cell insertion unit 3, an empty cell discard unit 4, and a cell transmission instruction unit 5 are provided.
[0022]
The empty cell separation unit 1 receives input of user cells, OAM cells, and empty cells from the transmission path, determines empty cells, separates them, and sends them to the empty cell discarding unit 4, while the remaining user cells and OAM cells are subjected to OAM processing. Send to part 2. The OAM processing unit 2 processes each ATM cell and sends the processed ATM cell to the empty cell insertion unit 3.
[0023]
Next, with reference to FIG. 2, the processing of ATM cells exceeding the one-cell transit time in the OAM processing unit 2 will be described.
[0024]
The OAM processing unit 2 adopts a pipeline method for each time T in consideration of the case of a system configuration in which ATM cells having a processing time exceeding the time T are continuous, assuming that the fixed time T is one cell passing time. I decided to. By the pipeline method, the total processing time of the continuous ATM cells is reduced.
[0025]
The empty cell insertion unit 3 transmits this received cell when it has received a processed cell from the OAM processing unit 2 when it receives a transmission instruction from the cell transmission instruction unit 5, while it is empty when it has not received it. Insert cell and output to outside.
[0026]
The empty cell discard unit 4 discards the empty cell received from the empty cell separation unit 1. The cell transmission instruction unit 5 measures the passage time of one cell as a fixed time T and instructs the empty cell insertion unit 3 to transmit every fixed time T. The cell transmission instruction unit 5 can be built in the empty cell insertion unit 3.
[0027]
Next, the main operation procedure in FIG. 1 will be described with reference to FIG. 1 and FIGS.
[0028]
FIG. 3 is a flowchart showing an example of a main operation procedure in which the empty cell insertion unit 3 in FIG.
[0029]
FIG. 4 is a diagram for explaining OAM processing for ATM cell input orders 1 to 10. In the illustrated cell, there are “empty cells” in the input sequences 3, 5, and 8, a user cell having a partial processing time of 1.2 times the passing time of one cell in the input sequence 2, Each user cell has a partial processing time that is 1.5 times the one-cell transit time.
[0030]
First, the empty cell separation unit 1 accepts cells according to the input order 1 to 10 and sends the cells in order 1, 2, 4, 6, 7, 9, 10 to the OAM processing unit 2. Cells of order 3, 5, 8 are sent to the empty cell discard unit 4 and discarded.
[0031]
As shown in FIG. 3, when the OAM processing unit 2 receives a cell, the OAM processing unit 2 starts partial processing 1 of the received cell.
[0032]
Since the user cell of the input order 1 shown in the figure has a partial processing time of “0.9 cells”, the OAM processing unit 2 ends the processing of the user cell of the input order 1 only by the partial process 1 and is an empty cell. It can be sent to the insertion unit 3. The empty cell insertion unit 3 holds the received user cell as a transmission waiting cell.
[0033]
The empty cell insertion unit 3 holds user cells that have been subjected to OAM processing in the input order 1 (YES in step S2), so when receiving a transmission instruction from the cell transmission instruction unit 5, the empty cell insertion unit 3 transmits the user cell in the first order (step S3 )it can.
[0034]
In this case, since the OAM processing unit 2 completes the OAM processing within the time of passing one cell, the OAM processing unit 2 can immediately take in the next cell and start the processing.
[0035]
Since the user cell of the input order 2 shown in the figure has a partial processing time of “1.2 times”, at the end of the partial processing 1 after the passage of one cell, the OAM processing unit 2 determines that the next part The process proceeds to process 2 and the process is still ongoing. Therefore, the empty cell insertion unit 3 cannot receive processed cells.
[0036]
At this time, when the empty cell insertion unit 3 receives the second order transmission instruction from the cell transmission instruction unit 5 in step S1, the empty cell insertion unit 3 does not hold the processed cell (NO in step S2). An empty cell is generated and sent as a second sequential output following the user cell of the sequential output (step S4).
[0037]
On the other hand, in the case shown in the figure, the user cell corresponding to the input order 2 is transmitted from the empty cell insertion unit 3 as the third order output following the empty cell because the cell processing is completed up to the partial process 2.
[0038]
Other cells are similarly OAM processed.
[0039]
In the embodiment described above, a total of 10 cells including 7 user cells and 3 OAM cells and 3 free cells are input to the empty cell separation unit. Since three empty cells are sent to the empty cell discarding unit by the empty cell separating unit and discarded, only seven cells in total, namely user cells and OAM cells, are input to the OAM processing unit. The OAM processing unit performs pipeline processing by dividing the processing into several partial processes in order to increase processing efficiency. In this partial processing unit, it is basically necessary to finish the processing within one cell passage time.
[0040]
Although 10 cells including empty cells are supposed to be processed in the OAM processing unit, only 7 cells excluding the empty cells are input, so that a margin for 3 cell passing time is generated in the partial processing unit. For this reason, OAM processing can be normally performed even if up to 3 cells out of 7 cells subjected to OAM processing exceed the passing time of one cell by partial processing. The empty cell insertion unit outputs the processed cell sent from the OAM processing unit as it is, but generates a free cell when the processing takes more than one cell passage time in the partial processing of the OAM processing unit. To allow the processing to be spared and absorb the excess of the passage time of one cell.
[0041]
In the above description, for convenience of explanation, the cell transmission instruction unit is illustrated as a functional block different from the empty cell insertion unit, but normally, the empty cell insertion unit is built in.
[0042]
As described above, the functional blocks and procedures shown in the drawings are used for explanation. However, changes such as distribution by separating and merging functions or changing the procedure before and after are free as long as the above functions are satisfied. However, the present invention can be applied to all OAM processing of ATM cells.
[0043]
【The invention's effect】
As described above, according to the present invention, it is possible to improve the processing efficiency and to obtain an effect that cells other than the empty cells can be output unchanged in the input order.
[0044]
The reason is that, since the input empty cell is discarded, the OAM processing has a time margin for the passing cell time corresponding to the number of empty cells, and an empty cell is inserted for processing exceeding one cell passing time. This is because the pipeline method is adopted for OAM processing and processing is performed in the input order.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing an embodiment of the present invention.
FIG. 2 is a diagram for explaining one mode of details of OAM processing in FIG. 1;
FIG. 3 is a flowchart showing one form of a main procedure related to an empty cell insertion unit in FIG. 1;
FIG. 4 is a diagram showing a partial form of change in the array of empty cells before and after OAM processing for explaining the present invention.
FIG. 5 is a diagram showing a partial form of an array of cells input to OAM processing.
FIG. 6 is a functional block diagram showing an example of the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Empty cell separation part 2 OAM processing part 3 Empty cell insertion part 4 Empty cell discard part 5 Cell transmission instruction | indication part

Claims (6)

In an OAM processing method in ATM (Asynchronous Transfer Mode) including processing related to maintenance and operation (OAM processing), empty cells are discarded from received cells, and cells other than empty cells are partially processed at fixed time intervals by a pipeline method. When the cells are output in the order of processing by performing the above, if one cell passage time is exceeded during the partial processing, an empty cell is inserted at that position and output, and the ATM OAM processing method is characterized in that. In an OAM processing method in ATM including processing related to maintenance / operation, a discarding procedure for discarding an empty cell from a received cell, a processing procedure for performing a partial process for each fixed time by a pipeline method on a cell excluding an empty cell, OAM processing in ATM, characterized by having an insertion procedure for outputting a processed cell every one cell passage time and inserting and outputting a blank cell at that position when there is no processed cell Method. In the OAM processing method in ATM (Asynchronous Transfer Mode) including processing related to maintenance and operation (OAM processing), a separation unit for separating empty cells from received cells and cells excluding empty cells are received and fixed by a pipeline method. A processing unit that performs partial processing for each time, and an insertion unit that inserts an empty cell at that position when there is no corresponding transmission cell when receiving a processed cell from the processing unit and outputting it to the outside An OAM processing method in ATM characterized by the above. 4. The OAM processing method in ATM according to claim 3 , further comprising a discard unit that receives and discards the separated empty cell. 4. The OAM processing method in ATM according to claim 3 , wherein the fixed time for performing the partial processing is one cell passing time. 4. The method according to claim 3 , wherein the insertion unit generates and inserts an empty cell when there is no processed cell to be output upon receiving a notification from an external cell transmission instruction unit that measures one cell passage time. OAM processing method in ATM characterized by the above.

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