JP5411090B2 - Buffer control method and buffer control apparatus - Google Patents

Description

  The present invention relates to a buffer control method and a buffer control device in a network device. In particular, the present invention relates to a buffer control method and a buffer control device in a downstream buffer of an ONU (Optical Network Unit: subscriber side device) in a PON (Passive Optical Network) system.

  However, the present invention is not limited to the downstream buffer of the ONU, and can be applied with various modifications to buffers of other network devices.

  The network device requires a large-capacity buffer when the interface on the output side is slower than the input side. An example of an ONU in a 10G-EPON system (10 Gigabit Ethernet (registered trademark) PON) will be described as an example of a network device that requires a large-capacity buffer.

  FIG. 7 shows an ONU downstream buffer in the 10G-EPON system. Downstream data (packets input to the ONU) with an effective bandwidth of 8.7 Gbit / s from the PON section is output to the UNI (User Network Interface) via the downstream buffer of the ONU. The ONU downlink buffer has a storage area for each priority type, and stores the downlink data in a predetermined area according to the priority type of the downlink data. In general, in many ONUs, the UNI communication speed is lower than the communication speed in the PON section, and thus a large-capacity buffer is required for downstream of the ONU.

  As a method of mounting the ONU downstream buffer in 10G-EPON, there is a method using an external memory similar to GE-PON (Non-Patent Document 1). When implemented using an external memory (hereinafter referred to as an external buffer), a dedicated control circuit and I / O are required in the ONU protocol control LSI (Large Scale Integrated circuit). Compared with the case where a memory is built in an LSI (hereinafter referred to as an internal buffer), the power consumption is large.

  For this reason, in order to realize the power saving of the network device that has been required for the network device in recent years and to reduce the power consumption of the ONU downlink buffer, the ONU downlink external buffer is made an internal buffer with low power consumption. It is effective.

  However, if a large-capacity buffer is mounted with a built-in memory, the chip area of the ONU protocol control LSI increases and the manufacturing cost of the LSI increases.

“PAS6201 Product Brief”, PMC-Sierra

  In a network device that requires a large-capacity buffer, it is necessary to reduce both the internal buffer capacity of the network device and save power in order to reduce the power consumption of the buffer by suppressing an increase in the chip area of the protocol control LSI chip. It is.

  It is an object of the present invention to provide a buffer control method and a buffer control device that can save power in a buffer of a network device with a small-capacity internal buffer.

According to a first aspect of the present invention, there is provided a buffer control method for a network device including an internal buffer for storing an input packet and an external buffer, and the sum of data amounts stored in the internal buffer and the external buffer is measured. When the threshold value is detected as A, the threshold flag is set as A, and when the threshold value is detected as below the predetermined threshold, the threshold flag is set as B. When the threshold flag is A, the external buffer is instructed to start External buffer activation instruction control processing step for instructing the external buffer to stop when the threshold flag is B and the external buffer is empty, and when the threshold flag is B, the storage destination of the input packet is determined as the internal buffer, When the threshold flag is A, the storage destination control processing step for determining the storage destination of the input packet in the external buffer; A storage control processing step for controlling the storage of the input packet in either the internal buffer or the external buffer according to the destination, a storage information management processing step for recording and managing at least the storage destination and the packet length of the input packet, and a storage information management processing A read control processing step for outputting a packet from either the internal buffer or the external buffer in accordance with the information recorded and managed in the step, and the internal buffer is composed of a normal area and an activation area, and the storage destination control process The step determines the storage destination of the input packet as the normal area of the internal buffer when the threshold flag is B, and sets the storage destination of the input packet as the startup area when the threshold flag is A and the external buffer is performing the startup process. If the threshold flag is A and the external buffer startup process is complete, the input packet That determine the bets storage destination into the external buffer.

According to a second aspect of the present invention, in a buffer control method for a network device including an internal buffer and an external buffer for storing input packets, the sum of data amounts stored in the internal buffer and the external buffer is measured, and the data amount is a predetermined threshold value. When the threshold value is detected as A, the threshold flag is set as A, and when the threshold value is detected as below the predetermined threshold, the threshold flag is set as B. When the threshold flag is A, the external buffer is instructed to start External buffer activation instruction control processing step for instructing the external buffer to stop when the threshold flag is B and the external buffer is empty, and when the threshold flag is B, the storage destination of the input packet is determined as the internal buffer, When the threshold flag is A, the storage destination control processing step for determining the storage destination of the input packet in the external buffer; A storage control processing step for controlling the storage of the input packet in either the internal buffer or the external buffer according to the destination, a storage information management processing step for recording and managing at least the storage destination and the packet length of the input packet, and a storage information management processing A read control processing step for outputting a packet from either the internal buffer or the external buffer in accordance with the information recorded and managed in the step, and the predetermined threshold is a first threshold and a second threshold (first Threshold> second threshold), the first threshold is the same value as the upper limit of the amount of data that can be stored in the internal buffer, and the second threshold is the amount of data less than or equal to the second threshold. Even if it is in the state of being stored in the file, the decision is made so that all the packets stored in the external buffer before the data amount reaches the first threshold can be output. In the step, the threshold flag is set to A when it is detected that the data amount exceeds the first threshold, the threshold flag is set to B when it is detected that the data amount is lower than the second threshold, and other values of the threshold flag you maintain.

According to a third aspect of the present invention, there is provided a buffer control method for a network device including an internal buffer and an external buffer for accumulating input packets, wherein the sum of the data amounts accumulated in the internal buffer and the external buffer is measured, When the threshold value is detected as A, the threshold flag is set as A, and when the threshold value is detected as below the predetermined threshold, the threshold flag is set as B. When the threshold flag is A, the external buffer is instructed to start External buffer activation instruction control processing step for instructing the external buffer to stop when the threshold flag is B and the external buffer is empty, and when the threshold flag is B, the storage destination of the input packet is determined as the internal buffer, When the threshold flag is A, the storage destination control processing step for determining the storage destination of the input packet in the external buffer; A storage control processing step for controlling the storage of the input packet in either the internal buffer or the external buffer according to the destination, a storage information management processing step for recording and managing at least the storage destination and the packet length of the input packet, and a storage information management processing A read control processing step for outputting packets from either the internal buffer or the external buffer according to the information recorded and managed in the step, and the storage areas of the internal buffer and the external buffer are divided according to the priority of the input packet. The determination processing step and the storage destination control processing step are performed for each priority of the input packet, and the external buffer activation instruction control processing step instructs the external buffer to activate when at least one threshold flag of each priority is A The threshold flags for each priority are all B and the external buffer is empty If there is, the stop instruction is given to the external buffer, and the storage control processing step determines that the input packet is assigned the priority of the internal buffer or the external buffer according to the storage destination determined by the same storage destination control processing step as the priority of the input packet. It stored in the storage area.

  The internal buffer consists of a normal area and a startup area, and the internal buffer normal area and the external buffer storage area are divided by priority, and the internal buffer startup area is not divided by priority. The storage destination control processing step for each priority determines that the input packet storage destination is the normal area of the internal buffer when the priority threshold flag is B, and the priority threshold flag is A and the external buffer is activated. When processing is performed, the storage destination of the input packet with the priority is determined as the activation area, and when the threshold flag of the priority is A and the startup processing of the external buffer is completed, the storage destination of the input packet May be determined as an external buffer.

According to a fourth aspect of the present invention, in a buffer control device of a network device including an internal buffer for storing an input packet and an external buffer, the sum of data amounts stored in the internal buffer and the external buffer is measured, and the data amount is a predetermined threshold value If the threshold value is A, the threshold flag is A when it is below the predetermined threshold value, and the threshold flag is B when the threshold value is A. External buffer activation instruction control processing means for instructing the external buffer to stop when the threshold flag is B and the external buffer is empty, and when the threshold flag is B, the storage destination of the input packet is determined as the internal buffer, Storage destination control processing means for determining the input packet storage destination in the external buffer when the threshold flag is A, and according to the input packet storage destination A storage control processing means for controlling the storage of the input packet in either the internal buffer or the external buffer, a storage information management processing means for recording and managing at least a storage destination and a packet length of the input packet, and recording by the storage information management processing means Read control processing means for outputting a packet from either the internal buffer or the external buffer according to managed information, the internal buffer is composed of a normal area and an activation area, and the storage destination control processing means is a threshold value When the flag is B, the storage destination of the input packet is determined in the normal area of the internal buffer. When the threshold flag is A and the external buffer is performing the startup process, the storage destination of the input packet is determined as the startup area. When the threshold flag is A and the external buffer startup processing is complete, the input buffer storage destination is determined as the external buffer. Ru configuration der that.

According to a fifth aspect of the present invention, in a buffer control device of a network device including an internal buffer for storing an input packet and an external buffer, the sum of the data amounts stored in the internal buffer and the external buffer is measured, and the data amount is a predetermined threshold value If the threshold value is A, the threshold flag is A when it is below the predetermined threshold value, and the threshold flag is B when the threshold value is A. External buffer activation instruction control processing means for instructing the external buffer to stop when the threshold flag is B and the external buffer is empty, and when the threshold flag is B, the storage destination of the input packet is determined as the internal buffer, Storage destination control processing means for determining the input packet storage destination in the external buffer when the threshold flag is A, and according to the input packet storage destination A storage control processing means for controlling the storage of the input packet in either the internal buffer or the external buffer, a storage information management processing means for recording and managing at least a storage destination and a packet length of the input packet, and recording by the storage information management processing means Read control processing means that outputs packets from either the internal buffer or the external buffer according to the information to be managed, and the storage area of the internal buffer and external buffer is divided according to the priority of the input packet The determination processing means and the storage destination control processing means are provided for each priority of the input packet, and the external buffer activation instruction control processing means is provided when at least one threshold flag of each priority is A. If the start command is given to the external buffer, and all the priority threshold flags are B and the external buffer is empty, The storage control processing means sends the input packet to the priority of the internal buffer or the external buffer according to the storage destination determined by the same storage destination control processing means as the priority of the input packet. Ru configuration der that stored in the storage area.

  The internal buffer consists of a normal area and an activation area. The internal area of the internal buffer and the storage area of the external buffer are divided according to the priority of the input packet, and the activation area of the internal buffer is divided according to the priority. The storage destination control processing means for each priority determines the storage destination of the input packet in the normal area of the internal buffer when the priority threshold flag is B, and the priority threshold flag is When A and the external buffer are performing the activation process, the storage destination of the input packet with the priority is determined as the activation area, and the priority threshold flag is A and the activation process of the external buffer is completed Alternatively, the storage destination of the input packet may be determined in the external buffer.

  The buffer control method and the buffer control device according to the present invention control the activation of the external buffer according to the data accumulation amount of the internal buffer and the external buffer, so that the packet is rarely input continuously for a long time. In this case, the amount of data stored in the buffer is less than the threshold value, and it is possible to store the input packet only with the internal buffer and stop the external buffer with high power consumption to save power.

  The present invention can also be applied to a buffer of a network device that controls the amount of data in the internal buffer and the external buffer based on the number of accumulated bytes or the number of accumulated packets.

  In the present invention, while the amount of accumulated data exceeds the threshold and the external buffer activation process is being performed, the input packet is accumulated in the activation area of the internal buffer, so that the input packet is discarded (data loss). Can be prevented.

  Further, the present invention can prevent data loss by preventing frequent switching between the internal buffer and the external buffer by using two threshold values.

  Further, the present invention enables switching between the internal buffer and the external buffer without data loss even when storage areas are secured in the internal buffer and the external buffer for each priority of the input packet. . The priority can be extracted from a CoS (Class of Service) field in the packet.

  Further, the present invention does not require the internal buffer activation area for each priority level, and the capacity of the internal buffer can be further reduced.

It is a figure which shows the structural example of the buffer control apparatus of Example 1 of this invention. It is a figure which shows the state machine of the threshold value flag of the judgment process part. 6 is a flowchart illustrating an example of a processing procedure of an external buffer activation instruction control processing unit 16 according to the first embodiment. 5 is a flowchart illustrating an example of a processing procedure of a storage destination control processing unit 17. It is a figure which shows the structural example of the buffer control apparatus of Example 2 of this invention. 12 is a flowchart illustrating an example of a processing procedure of an external buffer activation instruction control processing unit 16 according to the second embodiment. It is a figure which shows the downstream buffer of ONU in 10G-EPON.

FIG. 1 shows a configuration example of a buffer control apparatus according to a first embodiment of the present invention.
In FIG. 1, the buffer control apparatus according to the first embodiment includes an accumulation control processing unit 11, an internal buffer 12, an external buffer 13, an accumulation information management processing unit 14, a determination processing unit 15, an external buffer activation instruction control processing unit 16, and an accumulation destination. A control processing unit 17 and a read control processing unit 18 are included.

  The accumulation control processing unit 11 outputs the input packet to the internal buffer 12 or the external buffer 13 according to the accumulation destination determined by the accumulation destination control processing unit 17 and also the length of the input packet (hereinafter referred to as “packet length”). And the input packet information including at least the storage destination and the packet length of the input packet is output to the storage information management processing unit 14, the determination processing unit 15, and the storage destination control processing unit 17.

  The stored information management processing unit 14 records and manages input packet information, and reads output packet information used for reading from the internal buffer 12 and the external buffer 13 in response to a request from the read control processing unit 18. The result is output to the determination processing unit 15.

  The read control processing unit 18 obtains output packet information including the storage destination and the packet length from the storage information management processing unit 14, and determines whether the packet is read from the internal buffer 12 or the external buffer 13 based on the output packet information. The packet is read out and output. For example, in the case of the same priority, the oldest packet is output from the internal buffer 12 and the external buffer 13 together.

  The determination processing unit 15 measures the amount of data stored in the internal buffer 12 and the external buffer 13 based on the input packet information and the output packet information, determines whether the data amount is equal to or greater than a threshold, and sets the threshold flag. The data is output to the external buffer activation instruction control processing unit 16 and the storage destination control processing unit 17.

  The external buffer activation instruction control processing unit 16 issues an activation instruction or a stop instruction for the external buffer 13 by the activation instruction flag according to the threshold flag and the state of the external buffer 13, and the external buffer 13 performs an initialization process (hereinafter referred to as an activation instruction). , Referred to as “startup process”), a start process flag indicating whether or not it is in progress is output to the storage destination control processing unit 17.

  Each time the input packet information is input, the storage destination control processing unit 17 determines the storage destination of the input packet based on the threshold flag and the activation processing flag, and outputs it to the storage control processing unit 11.

  Here, the storage destination of the input packet is one of the normal area of the internal buffer 12, the activation area of the internal buffer 12, and the external buffer 13. The normal area and the activation area of the internal buffer 12 are storage areas obtained by dividing the storage area of the internal buffer 12. The activation area of the internal buffer 12 is an area for accumulating packets that are input until the activation process of the external buffer 13 is completed when the external buffer activation instruction control processing unit 16 issues an activation instruction to the external buffer 13. It is. The normal area of the internal buffer 12 is an accumulation area used when accumulating input packets in the internal buffer 12 except during the startup process of the external buffer 13.

  If the period during the activation process of the external buffer 13 is not taken into account or can be ignored, the activation area of the internal buffer 12 is unnecessary, and the accumulation destination control processing unit 17 determines the input packet according to only the threshold flag. The storage destination may be determined as either the internal buffer 12 or the external buffer 13.

  Hereinafter, details of the determination processing unit 15, the external buffer activation instruction control processing unit 16, and the accumulation destination control processing unit 17 when the internal buffer 12 includes a normal area and an activation area and the activation process of the external buffer 13 is considered. explain.

(1) Details of Determination Processing Unit 15 The determination processing unit 15 measures the amount of data stored in the internal buffer 12 and the external buffer 13, and determines whether the data amount is equal to or greater than a threshold value. The amount of data measured in the present embodiment is the sum of the number of accumulated bytes in the internal buffer 12 and the number of accumulated bytes in the external buffer 13 (hereinafter referred to as “buffer accumulated amount”). The buffer accumulation amount can be measured, for example, by subtracting the integrated value of the output packet length input from the stored information management processing unit 14 from the integrated value of the input packet length input from the storage control processing unit 11. . Further, the measurement of the buffer accumulation amount and the determination of whether or not the buffer accumulation amount is greater than or equal to the threshold value each time input packet information is input from the accumulation control processing unit 11 and output packet information is input from the accumulation information management processing unit 14. To implement.

  Here, a case where the first threshold value and the second threshold value (first threshold value> second threshold value) are used as threshold values for determining the threshold value of the data amount accumulated in the internal buffer 12 and the external buffer 13 will be described. However, when one threshold value is used, the first threshold value may be set to the second threshold value.

  The first threshold is the same value as the upper limit of the number of accumulated bytes that can be accumulated in the normal area of the internal buffer 12, and is a threshold used when switching the accumulation destination of the input packet from the internal buffer 12 to the external buffer 13. The second threshold is a threshold used when switching the storage destination of the input packet from the external buffer 13 to the internal buffer 12.

  When the buffer accumulation amount falls below the second threshold, the accumulation destination control processing unit 17 that inputs the threshold flag output from the determination processing unit 15 switches the input packet accumulation destination from the external buffer 13 to the internal buffer 12. That is, when the buffer accumulation amount falls below the second threshold, all input packets are input to the internal buffer 12, and the external buffer 13 only outputs the accumulated packets. In this state, before the external buffer 13 outputs all the packets, if the buffer accumulation amount exceeds the first threshold value, and packets are input to the external buffer 13 again, the data is not output to the external buffer 13. Old packets and newly entered packets are mixed. If they are mixed, the packet output order cannot be maintained. In order to prevent this, even when all the buffer accumulation amount equal to or less than the second threshold value is accumulated in the external buffer 13, the buffer accumulation amount is a reference for starting accumulation in the external buffer 13 again. A value that can output all the packets accumulated in the external buffer 13 before the threshold value is set as the second threshold value. As a result, the packets stored in the external buffer 13 are not mixed with old packets that have not been output and newly input packets.

FIG. 2 shows a state machine of the threshold flag of the determination processing unit 15.
In FIG. 2, the determination processing unit 15 sets the threshold flag to “1” when detecting that the measured buffer storage amount exceeds the first threshold (state S3). Further, when it is detected that the buffer accumulation amount is below the second threshold value, the threshold flag is set to “0” (state S4). In other states, the value of the threshold flag is maintained (state S2). The initial value of the threshold flag is “0” (state S1). Here, the state of “threshold flag is A” described in the claims corresponds to “1” of the threshold flag, and the state of “threshold flag is B” corresponds to “0” of the threshold flag. The value is not limited to “1” and “0” as long as it can be determined whether the value is above or below the threshold.

(2) Details of External Buffer Activation Instruction Control Processing Unit 16 The external buffer activation instruction control processing unit 16 instructs the external buffer 13 to start or stop according to the threshold flag of the determination processing unit 15 and the state of the external buffer 13. And an activation process flag indicating whether or not the external buffer 13 is in the activation process is output to the storage destination control processing unit 17.

FIG. 3 illustrates an example of a processing procedure of the external buffer activation instruction control processing unit 16 according to the first embodiment.
In FIG. 3, it is determined whether the threshold flag input from the determination processing unit 15 is “1” or “0” (step H1). If the threshold flag is “0” (step H1: No), the process proceeds to step H1. Return. If the threshold flag is “1” (step H1: Yes), it means that the buffer accumulation amount exceeds the accumulation amount that can be accumulated in the normal area of the internal buffer 12, and accumulation in the external buffer 13 is necessary. Therefore, the activation instruction flag is set to “1” and an activation instruction is issued to the external buffer 13 (step H2). During the activation process of the external buffer 13, the activation process flag indicating that the activation process is in progress is set to “1” (step H2). When the completion of the activation process is notified from the external buffer 13 (step H3), the activation process flag is set. Is set to “0” (step H4). When the threshold flag becomes “1” and the activation process flag becomes “0”, the accumulation destination control processing unit 17 switches the accumulation destination of the input packet from the internal buffer 12 to the external buffer 13. The external buffer activation instruction control processing unit 16 keeps the activation instruction flag “1” and the activation process flag “0” until the buffer accumulation amount falls below the second threshold and the threshold flag becomes “0” ( Step H5).

  Next, when the threshold flag becomes “0”, the accumulation destination control processing unit 17 switches the accumulation destination of the input packet from the external buffer 13 to the normal area of the internal buffer 12, stops the accumulation in the external buffer 13, and only reads. Is done. Here, when the external buffer activation instruction control processing unit 16 receives a notification from the external buffer 13 that the external buffer 13 is empty (step H6), the external buffer activation instruction control processing unit 16 sets the activation instruction flag to “0” to the external buffer 13. A stop instruction is issued (step H7), and the process returns to step H1. The initial values of the activation process flag and the activation instruction flag are both “0”.

(3) Details of Storage Destination Control Processing Unit 17 The storage destination control processing unit 17 uses the threshold flag input from the determination processing unit 15 and the start processing flag input from the external buffer start instruction control processing unit 16 to input packets. Determine the storage location of. The storage destination of the input packet is one of the normal area of the internal buffer 12, the activation area of the internal buffer 12, and the external buffer 13.

FIG. 4 shows an example of the processing procedure of the storage destination control processing unit 17.
In FIG. 4, the accumulation destination control processing unit 17 performs the following process every time input packet information is received from the accumulation control processing unit 11. It is determined whether the threshold flag input from the determination processing unit 15 is “1” or “0” (step G 1). If the threshold flag is “0” (step G 1: No), the buffer accumulation amount is the internal buffer 12. Therefore, the storage area of the input packet is determined as the normal area of the internal buffer 12 (step G3). If the threshold flag is “1” (step G1: Yes), it means that the buffer accumulation amount is equal to or greater than the first threshold value and exceeds the accumulation amount that can be accumulated in the normal area of the internal buffer 12. In this case, it is confirmed by the activation process flag whether or not the external buffer 13 is being activated (step G2). When the activation process flag is “1” and the external buffer 13 is in the activation process (step G2: Yes), the storage destination of the input packet is determined as the activation area of the internal buffer 12 (step G4). ). Further, when the activation process flag is “0”, it means that the external buffer 13 has already been activated, and therefore the storage destination of the input packet is determined in the external buffer 13 (step G5).

FIG. 5 shows a configuration example of the buffer control apparatus according to the second embodiment of the present invention.
5, the accumulation control processing unit 11, the internal buffer 12, the external buffer 13, the accumulation information management processing unit 14, the determination processing unit 15, the external buffer activation instruction control processing unit 16, and the accumulation constituting the buffer control device of the second embodiment. The destination control processing unit 17 and the read control processing unit 18 have the same functions as those in the first embodiment. A feature of the present embodiment is that a determination processing unit 15 and a storage destination control processing unit 17 are provided for each priority, and the external buffer activation instruction control processing unit 16 is connected to the external buffer 13 according to the determination result of the determination processing unit 15 for each priority. It is in the place of starting and stopping instructions.

Hereinafter, the difference from each part of the first embodiment will be mainly described.
The storage control processing unit 11 extracts the priority from the CoS (Class of Service) field of the input packet, and notifies the storage information management processing unit 14, the judgment processing unit 15 and the storage destination control processing unit 17 of the input packet information packet. The difference from the first embodiment is that the priority is included in the length and storage destination.

  The storage information management processing unit 14 is different from the first embodiment in that it records and manages input packet information including at least the packet length, storage destination, and priority of the input packet from the storage control processing unit 11.

  Based on the output packet information including at least the packet length, storage destination, and priority from the storage information management processing unit 14, the read control processing unit 18 stores each priority storage area or internal buffer 12 in the internal buffer 12 or the external buffer 13. This is different from the first embodiment in that a packet is read out from the start area and output.

  The determination processing unit 15 corresponding to each priority receives input packet information from the accumulation control processing unit 11 and determines whether the information is the priority of the determination processing unit 15. If it is the priority of the determination processing unit 15, the input packet length is added to the buffer accumulation amount measured by the determination processing unit 15. Further, output packet information is input from the accumulated information management processing unit 14, and similarly, it is determined whether or not the information is a priority of the determination processing unit 15. If it is the priority of the determination processing unit 15, the output packet length is subtracted from the buffer accumulation amount measured by the determination processing unit 15. Therefore, the obtained buffer accumulation amount is the buffer accumulation amount for each priority, and becomes a different value for each priority determination processing unit 15. Further, the first threshold value and the second threshold value are different values for each priority, and a threshold flag is provided for each priority. The threshold flag for each priority is output by the determination processing unit 15 corresponding to each priority.

  The first threshold of the predetermined priority is the same value as the number of accumulated bytes that can be accumulated in the accumulation area of the priority in the normal area of the internal buffer 12, and the second threshold of the predetermined priority is the priority. Even when all the stored bytes less than or equal to the second threshold value are stored in the external buffer 13, the stored number of bytes of the priority level is stored in the external buffer 13 before the priority level becomes the first threshold value. It is a value that can output all accumulated packets. Further, the threshold flag of a predetermined priority is controlled by the same state machine as in FIG. 2 based on the buffer accumulation amount of the predetermined priority.

  The external buffer start instruction control processing unit 16 instructs the external buffer 13 to start or stop according to the value of the threshold flag for each priority.

FIG. 6 illustrates an example of a processing procedure of the external buffer activation instruction control processing unit 16 according to the second embodiment.
In FIG. 6, it is determined whether the logical sum (OR) of the threshold flags for each priority input from the determination processing unit 15 is “1” or “0” (step J1), and when it is “0” (step J1: No ) Returns to Step J1. When the logical sum of the threshold flags for each priority is “1” (step J1: Yes), the buffer accumulation amount of any priority exceeds the accumulation amount that can be accumulated in the normal area of the internal buffer 12, Since it means that accumulation in the external buffer 13 is necessary, the activation instruction flag is set to “1” and an activation instruction is issued to the external buffer 13 (step J2). During the startup process of the external buffer 13, the startup process flag indicating that the startup process is in progress is set to “1” (step J2). When the completion of the startup process is notified from the external buffer 13 (step J3), the startup process flag is set. Is set to “0” (step J4). Here, the start instruction is given until all of the buffer accumulation amounts of the respective priorities are below the second threshold, the threshold flags of the respective priorities are “0”, and the negative logical sum (NOR) thereof is “1”. The flag is “1” and the activation process flag is “0” (step J5).

  Next, when the negative logical sum of the threshold flags of the respective priorities becomes “1” and the external buffer 13 is notified that the external buffer 13 is empty (step J6), the activation instruction flag is set to “0”. The stop instruction is issued to the external buffer 13 (step J7), and the process returns to step J1. Note that the activation processing flag and the activation instruction flag are single values regardless of the priority, and both initial values are “0”. In addition, the external buffer activation instruction control processing unit 16 performs the logical sum and negative logical sum of the threshold flags of the respective priorities.

  The storage destination control processing unit 17 is provided for each priority, divides the storage area for each priority in the normal area of the internal buffer 12 and the external buffer 13, and sets the storage destination in the normal area of the internal buffer 12 or the external buffer 13. When the determination is made, the storage destination is determined in the storage area having a predetermined priority. Here, the activation area of the internal buffer 12 does not divide the accumulation area for each priority, and when the activation process flag is “1”, all input packets with the priority of the threshold flag “1” are activated. Accumulate in the working area.

  In this embodiment, three types of priorities are used. However, even if the priority is not three, various modifications can be applied without departing from the spirit of the present invention.

  The determination processing unit 15 of the present embodiment measures the number of accumulated packets from the sum of the number of accumulated bytes of the internal buffer 12 and the external buffer 13 in the first embodiment or the second embodiment. It is characterized by. For this reason, the first threshold value and the second threshold value are different from those in the first and second embodiments. The first threshold is the number of packets that can be stored in the storage capacity of the internal buffer 12 for each priority. The second threshold value is the number of packets before the first threshold value reaches the first threshold value even when packets are continuously input in a state where all the packet numbers equal to or smaller than the second threshold value are accumulated in the external buffer 13. This is a value that can output all the packets stored in the external buffer 13.

  In the measurement of the buffer accumulation amount, 1 is added to the buffer accumulation amount when a packet is input, and 1 is subtracted from the buffer accumulation amount when the packet is output. The acquisition destination of the information regarding the presence / absence of the input packet and the presence / absence of the output packet is arbitrary.

DESCRIPTION OF SYMBOLS 11 Storage control processing part 12 Internal buffer 13 External buffer 14 Storage information management processing part 15 Judgment processing part 16 External buffer starting instruction control processing part 17 Storage destination control processing part 18 Read control processing part

Claims (7)

In a buffer control method for a network device comprising an internal buffer for storing input packets and an external buffer,
Measures the sum of the amount of data stored in the internal buffer and the external buffer, detects that the data amount exceeds a predetermined threshold, sets the threshold flag to A, and detects that the data amount is below the predetermined threshold A determination processing step in which the threshold flag is set to B when
An external buffer activation instruction control processing step for instructing the external buffer to start when the threshold flag is A, and for instructing the external buffer to stop when the threshold flag is B and the external buffer is empty;
A storage destination control processing step of determining the storage destination of the input packet in the internal buffer when the threshold flag is B, and determining the storage destination of the input packet in the external buffer when the threshold flag is A;
A storage control processing step for controlling the storage of the input packet in either the internal buffer or the external buffer according to a storage destination of the input packet;
A storage information management processing step for recording and managing at least a storage destination and a packet length of the input packet;
A read control processing step for outputting a packet from either the internal buffer or the external buffer according to the information recorded and managed in the stored information management processing step;
Have
The internal buffer is composed of a normal area and an activation area,
In the storage destination control processing step, when the threshold flag is B, the storage destination of the input packet is determined to be a normal area of the internal buffer, and the threshold flag is A and the external buffer is performing a startup process The input packet storage destination is determined as the activation area, and the input packet storage destination is determined as the external buffer when the threshold flag is A and the external buffer activation processing is completed. A characteristic buffer control method. In a buffer control method for a network device comprising an internal buffer for storing input packets and an external buffer,
Measures the sum of the amount of data stored in the internal buffer and the external buffer, detects that the data amount exceeds a predetermined threshold, sets the threshold flag to A, and detects that the data amount is below the predetermined threshold A determination processing step in which the threshold flag is set to B when
An external buffer activation instruction control processing step for instructing the external buffer to start when the threshold flag is A, and for instructing the external buffer to stop when the threshold flag is B and the external buffer is empty;
A storage destination control processing step of determining the storage destination of the input packet in the internal buffer when the threshold flag is B, and determining the storage destination of the input packet in the external buffer when the threshold flag is A;
A storage control processing step for controlling the storage of the input packet in either the internal buffer or the external buffer according to a storage destination of the input packet;
A storage information management processing step for recording and managing at least a storage destination and a packet length of the input packet;
A read control processing step for outputting a packet from either the internal buffer or the external buffer according to the information recorded and managed in the stored information management processing step;
Have
The predetermined threshold is a first threshold and a second threshold (first threshold> second threshold),
The first threshold value is the same value as the upper limit of the data amount that can be stored in the internal buffer, and the second threshold value is that all the data amount equal to or less than the second threshold value is stored in the external buffer. Even if it is in a state, it is a value that can output all the packets accumulated in the external buffer before the data amount reaches the first threshold,
In the determination processing step, the threshold flag is set to A when it is detected that the data amount exceeds the first threshold, and the threshold flag is set to B when it is detected that the data amount is lower than the second threshold. And the others maintain the value of the threshold flag. In a buffer control method for a network device comprising an internal buffer for storing input packets and an external buffer,
Measures the sum of the amount of data stored in the internal buffer and the external buffer, detects that the data amount exceeds a predetermined threshold, sets the threshold flag to A, and detects that the data amount is below the predetermined threshold A determination processing step in which the threshold flag is set to B when
An external buffer activation instruction control processing step for instructing the external buffer to start when the threshold flag is A, and for instructing the external buffer to stop when the threshold flag is B and the external buffer is empty;
A storage destination control processing step of determining the storage destination of the input packet in the internal buffer when the threshold flag is B, and determining the storage destination of the input packet in the external buffer when the threshold flag is A;
A storage control processing step for controlling the storage of the input packet in either the internal buffer or the external buffer according to a storage destination of the input packet;
A storage information management processing step for recording and managing at least a storage destination and a packet length of the input packet;
A read control processing step for outputting a packet from either the internal buffer or the external buffer according to the information recorded and managed in the stored information management processing step;
Have
Dividing the storage area of the internal buffer and the external buffer for each priority of the input packet,
The determination processing step and the storage destination control processing step are performed for each priority of the input packet,
The external buffer activation instruction control processing step issues an activation instruction to the external buffer when at least one of the threshold flags of each priority is A, and all the threshold flags of each priority are B and the external buffer is If empty, instruct the external buffer to stop,
The storage control processing step stores the input packet in the storage area of the priority of the internal buffer or the external buffer according to the storage destination determined by the same storage destination control processing step as the priority of the input packet. A buffer control method characterized by the above. The buffer control method according to claim 3 , wherein
The internal buffer is composed of a normal area and an activation area,
Dividing the normal area of the internal buffer and the storage area of the external buffer for each priority, the activation area of the internal buffer is not divided for each priority,
The storage destination control processing step for each priority determines the storage destination of the input packet in the normal area of the internal buffer when the priority threshold flag is B, and the priority threshold flag is A and the When the external buffer is performing the activation process, the storage destination of the input packet with the priority is determined as the activation area, the priority threshold flag is A, and the activation process of the external buffer is completed And determining the storage destination of the input packet in the external buffer. In a buffer control device of a network device comprising an internal buffer for storing input packets and an external buffer,
Measures the sum of the amount of data stored in the internal buffer and the external buffer, detects that the data amount exceeds a predetermined threshold, sets the threshold flag to A, and detects that the data amount is below the predetermined threshold Determination processing means for setting the threshold flag to B when
An external buffer start instruction control processing means for instructing the external buffer to start when the threshold flag is A, and for instructing the external buffer to stop when the threshold flag is B and the external buffer is empty;
Storage destination control processing means for determining the storage destination of the input packet in the internal buffer when the threshold flag is B, and determining the storage destination of the input packet in the external buffer when the threshold flag is A;
Accumulation control processing means for controlling accumulation of the input packet in either the internal buffer or the external buffer according to a storage destination of the input packet;
Storage information management processing means for recording and managing at least a storage destination and a packet length of the input packet;
Read control processing means for outputting a packet from either the internal buffer or the external buffer according to information recorded and managed by the stored information management processing means;
With
The internal buffer is composed of a normal area and an activation area,
When the threshold flag is B, the storage destination control processing means determines the storage destination of the input packet as a normal area of the internal buffer, the threshold flag is A, and the external buffer is performing a startup process The storage destination of the input packet is determined as the activation area, and the storage destination of the input packet is determined as the external buffer when the threshold flag is A and the startup processing of the external buffer is completed. A buffer controller characterized by being. In a buffer control device of a network device comprising an internal buffer for storing input packets and an external buffer,
Measures the sum of the amount of data stored in the internal buffer and the external buffer, detects that the data amount exceeds a predetermined threshold, sets the threshold flag to A, and detects that the data amount is below the predetermined threshold Determination processing means for setting the threshold flag to B when
An external buffer start instruction control processing means for instructing the external buffer to start when the threshold flag is A, and for instructing the external buffer to stop when the threshold flag is B and the external buffer is empty;
Storage destination control processing means for determining the storage destination of the input packet in the internal buffer when the threshold flag is B, and determining the storage destination of the input packet in the external buffer when the threshold flag is A;
Accumulation control processing means for controlling accumulation of the input packet in either the internal buffer or the external buffer according to a storage destination of the input packet;
Storage information management processing means for recording and managing at least a storage destination and a packet length of the input packet;
Read control processing means for outputting a packet from either the internal buffer or the external buffer according to information recorded and managed by the stored information management processing means;
With
The storage area of the internal buffer and the external buffer is configured to be divided for each priority of the input packet,
The determination processing means and the storage destination control processing means are provided for each priority of the input packet,
The external buffer activation instruction control processing unit issues an activation instruction to the external buffer when at least one threshold flag of each priority is A, and all the threshold flags of each priority are B and the external buffer is If empty, the external buffer is instructed to stop,
The storage control processing means is configured to store the input packet in the storage area of the priority of the internal buffer or the external buffer according to the storage destination determined by the same storage destination control processing means as the priority of the input packet. A buffer control device characterized in that The buffer control device according to claim 6 .
The internal buffer is composed of a normal area and an activation area,
The normal area of the internal buffer and the storage area of the external buffer are divided for each priority of the input packet, and the activation area of the internal buffer is not divided for each priority,
The storage destination control processing means for each priority determines the storage destination of the input packet in the normal area of the internal buffer when the priority threshold flag is B, and the priority threshold flag is A and the When the external buffer is performing the activation process, the storage destination of the input packet with the priority is determined as the activation area, the priority threshold flag is A, and the activation process of the external buffer is completed The buffer control device is characterized in that the storage destination of the input packet is determined in the external buffer.

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