JP4957604B2 - Communication control device - Google Patents

Description

  The present invention relates to a communication control apparatus, and more particularly to a communication control apparatus including a plurality of buffer units for packets.

  The communication control apparatus that performs packet transfer performs packet analysis processing such as switching processing and routing processing on the received packet. In order to absorb an instantaneous transmission / reception transfer rate difference caused by the packet analysis processing, an individual buffer unit is provided for each port. The size of the buffer unit is determined according to, for example, the maximum transfer rate of each port, the maximum transmission / reception transfer rate difference, the allowable delay (latency) in the network device, and the like.

  In a communication control apparatus having a plurality of buffer units, received packets are distributed and stored in a plurality of buffer units, a predetermined buffer unit is selected from the plurality of buffer units, and a packet is extracted from the selected buffer unit. It is necessary to perform processing to send. Here, a round robin method is known as a technique for transmitting a packet using a buffer unit. The round robin method is a method in which each buffer unit is selected (in order). Therefore, in the round robin method, received packets are stored in order in each buffer unit, and the stored packets are sequentially extracted from each buffer unit and transmitted.

  Various techniques for transmitting packets using this round robin method have been disclosed (for example, Patent Document 1).

JP 2000-092070 A

  However, for example, the technique disclosed in Patent Document 1 has a problem in that the packet transmission order is changed when a packet is discarded in the buffer unit.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to accumulate received packets in order in each buffer unit, and to retrieve the accumulated packets in order from each buffer unit. Therefore, it is an object of the present invention to provide a communication control apparatus capable of maintaining the order of transmission packets even when packets are discarded in a buffer unit.

  In order to solve the above-described problem, according to an aspect of the present invention, there is provided a communication control apparatus including a plurality of buffer units that set and accumulate input packets as extraction targets in the order of input. A receiving buffer distribution unit that receives input of packets through a plurality of ports, and distributes and outputs the packets to a plurality of buffer units in order, and a monitoring process that monitors packet discard states in the plurality of buffer units. A transmission buffer allocating unit that performs extraction processing for extracting packets from the plurality of buffer units in the order in which the reception buffer allocating unit accepts input based on the discard state, and that sequentially outputs the extracted packets. A communication control device is provided.

  As described above, according to the present invention, received packets are stored in order in each buffer unit, and when the stored packets are sequentially extracted from each buffer unit and transmitted, packet discarding in the buffer unit is prevented. Even if it occurs, it is possible to provide a communication control apparatus that can keep the order of transmission packets normal.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  FIG. 1 is a diagram illustrating a configuration example of a general communication control apparatus (part 1). A configuration example of a general communication control device (part 1) will be described with reference to FIG.

  As shown in FIG. 1, a general communication control apparatus 600A includes individual buffer units 800 to 890 at the ports P0 to P9. The reception port distribution unit 700 distributes the received packets to the buffer units 800 to 890, and the transmission port distribution unit 900 extracts and transmits the packets accumulated in the buffer units 800 to 890. As a result, the instantaneous transmission / reception transfer rate difference generated by the packet analysis processing performed by the communication control device 600A is absorbed.

  In recent years, usage modes of network systems have been diversified, and there is a strong demand for those in which the buffer size can be changed according to changes in each usage mode and communication status. The inventors of the present application have developed a new technology as one of the technologies corresponding to these demands.

  According to this technology, a plurality of buffers of a fixed size are prepared, and the buffer amount allocated to each port is “port link information”, “retention amount of remaining packets in the buffer”, and “time for packets to pass through the buffer”. It is dynamically determined by the number of fixed-size buffers allocated accordingly.

  Packets received from each port are stored in a sequence of processing methods (round robin) for each packet in a plurality of fixed size buffers assigned, and when transmitting from the buffer, one packet is sent from all the buffers in round robin as with reception. It is extracted and sent one by one. As a result, the transfer rate bandwidth assigned to each port is inevitably determined by the number of fixed size buffers to be used.

  FIG. 2 is a diagram illustrating a configuration example of a general communication control device (part 2). A configuration example of a general communication control apparatus (part 2) will be described with reference to FIG.

  As shown in FIG. 2, a general communication control device 600B includes individual buffer units 800 to 890 at each port. The reception buffer distribution unit 710 distributes the received packets to the buffer units 800 to 890, and the transmission port distribution unit 910 extracts the packets stored in the buffer units 800 to 890 and transmits them.

  For example, in order to process 10 ports of 10 Mbps, in a configuration using 10 buffer units 800 to 890 corresponding to each port, the configuration of the buffer units 800 to 890 is maintained and one port of 100 Mbps is processed. Think about the case. The reception buffer distribution unit 710 distributes the packets to the buffer units 800 to 890 in the order of reception. In the transmission buffer distribution unit 910, packets are sequentially extracted from the buffer units 800 to 890 and transmitted.

  FIG. 3 is a schematic diagram illustrating an operation example in a general communication control apparatus (part 2). With reference to FIG. 3, the operation example in a general communication control apparatus (the 2) is demonstrated.

  FIG. 3 schematically shows a packet flow when the communication control apparatus (part 2) shown in FIG. 2 is operated. Here, the number displayed on each packet is given for convenience in order to indicate the reception order of the received packets, and is not related to the contents of the packets. Also, it is not related to the actual packet. In practice, the packets are generally not numbered. The same applies to the following unless otherwise specified. For the sake of clarity, the received packet is not transmitted immediately after reception, but is illustrated as being transmitted after staying in the buffer units 800 to 890. As shown in FIG. 3, the packets are sequentially stored in the buffer units 800 to 890.

  FIG. 4 is a schematic diagram illustrating an operation example in a general communication control apparatus (part 2). With reference to FIG. 4, the operation example in a general communication control apparatus (the 2) is demonstrated.

  FIG. 4 schematically shows a packet flow when the communication control apparatus (part 2) shown in FIG. 2 is operated. However, for simplification, a round robin packet process using four buffer units 800 to 830 is shown.

  FIG. 4 shows an example in which the communication control device 600B receives 18 packets. The reception buffer distribution unit 710 distributes the packets from the buffer unit 800 to the buffer unit 830 in the order in which the packets are received. In response to the transmission request from each of the buffer units 800 to 830, the transmission buffer allocating unit 910 sequentially extracts packets and performs transmission processing.

  The buffer units 800 to 830 manage packets in the order received from the reception buffer allocating unit 710, store the order, and issue a transmission request to the transmission buffer allocating unit 910 (FIFO (First In First Out) operation) ). Focusing on the buffer unit 810, the first, fifth, ninth, thirteenth, and seventeenth packets are accumulated in the buffer, and are transmitted in this order.

  FIG. 5 is a schematic diagram illustrating an operation example in a general communication control apparatus (part 2). With reference to FIG. 5, the operation example in a common communication control apparatus (the 2) is demonstrated.

  FIG. 5 shows an example in which the fifth packet is discarded. The discarding occurs, for example, by packet processing (discarding by packet analysis, discarding by buffer overflow, etc.) in the buffer unit 810 after packet sorting by the reception buffer sorting unit 710. As shown in FIG. 5, up to the fourth packet is normally transmitted in the order received.

  FIG. 6 is a schematic diagram illustrating an operation example in a general communication control apparatus (part 2). With reference to FIG. 6, the operation example in a general communication control apparatus (the 2) is demonstrated.

  FIG. 6 shows a state in the buffer unit 810 due to the discard of the fifth packet. Since the fifth packet is discarded, the buffer after the first packet becomes the ninth packet in the buffer unit 810. When transmission by round robin is performed in the transmission buffer allocating unit 910, the ninth packet is transmitted after the fourth packet as shown in FIG. This is a state in which the order of the packets is changed. Further, after that, the packets in the buffer unit 810 are transmitted one round earlier than the packets stored in the other buffer units 800, 820, and 830. This state continues until there are no packets remaining in the buffer units 800 to 830.

  Ideally, as shown in the lower part of FIG. 6, even if the fifth packet is discarded, it is desirable that the subsequent packet order be transmitted without being changed. In general, in an IP (Internet Protocol) packet, even if the order of the packets is changed, the packet is restored and assembled at the terminal portion, and there is no problem in communication itself. Further, in the IP network, the order of packets is generally not guaranteed, and it is not uncommon for the order to change. However, recently, voice and video have flowed through the IP network, and quality control has become important. It is not preferable that the order of packets whose priority is controlled by a quality control device or the like is changed within the network. For this reason, there is a problem in the simple round robin control by the general communication control device as described above, and it should be avoided that the packet order is continuously changed.

(First embodiment)
FIG. 7 is a schematic diagram illustrating a configuration example of the communication control apparatus according to the first embodiment. A configuration example of the communication control apparatus according to the first embodiment will be described with reference to FIG.

(Constitution)
The communication control unit 100A according to the first embodiment includes a reception buffer distribution unit 710, buffer units 300A to 330A, and a transmission buffer distribution unit 400A.

  The reception buffer distribution unit 710 receives packet input via one or a plurality of ports (not shown). The reception buffer allocating unit 710 distributes the received packets to the buffer units 300A to 330A in order (in a round robin manner) and outputs the packets. That is, the reception buffer allocating unit 710 has the same configuration as the reception buffer allocating unit 710 in the above-described general communication control apparatus (part 2).

  The buffer units 300A to 330A set the input packets as extraction targets in the input order and store them. Here, four buffer units are provided. However, any number of buffer units may be used. In the first embodiment, at least one of the buffer units 300A to 330A has a discard number counter indicating the number of discarded packets in each of the buffer units 300A to 330A. Count up the discard counter. Here, a case where the buffer unit 810A has a discard number counter will be described as an example, but two or more buffer units out of the buffer units 300A to 330A may have a discard number counter.

  The transmission buffer distribution unit 400A performs a monitoring process for monitoring the packet discard state in the buffer unit 810A having a discard number counter. Based on this discard state, the transmission buffer allocating unit 400A performs extraction processing for extracting packets from the buffer units 300A to 330A in the order in which the reception buffer allocating unit 710 receives input, and outputs the extracted packets in order. .

  In the first embodiment, the transmission buffer allocating unit 400A monitors the buffer unit 310A having the discard number counter by monitoring whether or not the discard number counter is counted up. Also, the transmission buffer allocating unit 400A has a discard number counter when the discard number counter is counted up when performing extraction processing by extracting packets sequentially from the buffer units 300A to 330A. The extraction of the packet from 310A is skipped. That is, the transmission buffer allocating unit 400A skips packet extraction from the buffer unit 310A based on the discard number counter presented from the buffer unit 310A having the discard number counter in addition to the normal round robin packet extraction operation. (Skip). In addition, in the extraction process, the transmission buffer sorting unit 400A may further perform a process of counting down the discard number counter when the discard number counter is counted up.

  As to whether or not the discard number counter has been counted up, for example, the buffer unit 310A having the discard number counter presents the discard number counter in the buffer unit together with the packet transmission request to the transmission buffer allocating unit 400A. If so, it can be monitored.

  The reception buffer allocating unit 710, the buffer units 300A to 330A, and the transmission buffer allocating unit 400A are realized, for example, by executing a program stored in a memory by a CPU (Central Processing Unit). Further, each of the buffer units 300A to 330A has a memory for storing packets, for example, and the packets are stored by storing the packets in the memories.

  FIG. 8 is a schematic diagram illustrating an operation example of the communication control apparatus according to the first embodiment. With reference to FIG. 8, an operation example of the communication control apparatus according to the first embodiment will be described.

(Operation)
Here, the reception buffer allocating unit 710 distributes and accumulates the received packets in the buffer unit in order by the round robin method (takes out the packets in order from the buffer unit 300A, the buffer unit 310A, the buffer unit 320A, and the buffer unit 330A). Then, the packets are stored again in order from the buffer unit 300A). In addition, the transmission buffer allocating unit 400A also sequentially extracts packets by the round robin method. Further, as an example, it is assumed that the buffer unit 310A has a discard number counter. Here, it is assumed that the initial value of the discard number counter is set to 0.

  When packet discard occurs in the buffer unit 310A, the buffer unit 310A counts up the discard number counter (for example, adds 1). In the example shown in FIG. 8, the fifth packet is discarded in the buffer unit 310A. In this case, the buffer unit 310A counts up its own discard number counter (for example, changes from 0 to 1).

  The transmission buffer allocating unit 400A monitors the discard number counter included in the buffer unit 310A, and if it determines that the discard number counter has been counted up, skips packet extraction from the buffer unit 310A. In the example illustrated in FIG. 8, the transmission buffer allocating unit 400A skips the extraction of the ninth packet from the buffer unit 310A after extracting the fourth packet from the buffer unit 300A.

  The transmission buffer allocating unit 400A may count down (for example, subtract 1) from the discard number counter of the buffer unit 310A when skipping packet extraction from the buffer unit 310A (for example, 1 to 0). Then, the transmission buffer allocating unit 400A takes out the eighth packet from the buffer unit 300A, determines that the discard number counter of the buffer unit 310A has been counted down, and determines the ninth packet from the buffer unit 310A. Can be taken out. That is, the buffer unit 310A is skipped in the packet extraction process by the round robin method as many times as the number of packet discards.

(effect)
In the conventional round robin method, the phenomenon that the order of transmission packets continues until the buffer becomes empty (there are no remaining packets in the buffer), whereas according to the first embodiment, discarding is performed. After the original packet extraction timing (when not discarded) comes, the order of the transmitted packets returns to the order in which they were received (see FIGS. 7 and 8).

  In the first embodiment, since the packet is skipped at the packet discard timing, the order of the transmitted packets is changed until the original timing (when not discarded) of the discarded packet comes. In comparison, it can be expected that the time until the replacement of the order of transmission packets is finite and the frequency of replacement as a whole decreases.

(Second Embodiment)
In the first embodiment, it can be expected that the frequency of packet rearrangement is lower than in the conventional case. However, it is also conceivable that the order rearrangement increases in packet discard at the time of reception such as buffer congestion discard. Therefore, a technique in which the packet order is not changed even when packet discard occurs at the time of reception will be described as a second embodiment.

  FIG. 9 is a schematic diagram illustrating a configuration example of a communication control apparatus according to the second embodiment. With reference to FIG. 9, the structural example of the communication control apparatus which concerns on 2nd Embodiment is demonstrated.

(Constitution)
The communication control unit 100B according to the second embodiment includes a reception buffer allocating unit 200, buffer units 300B to 330B, and a transmission buffer allocating unit 400B.

  When receiving a packet input via one or a plurality of ports, the reception buffer allocating unit 200 further performs a process of giving a reception number indicating the ordinal number of the received packet to the received packet. . The reception buffer distribution unit 200 is different from the reception buffer distribution unit 710 in the first embodiment in this respect. (1) The number is embedded in the packet, (2) overhead is added to the packet, and the number is written therein. (3) The number is passed to the buffer units 300B to 330B for management separately from the packet. There are various methods, but any number can be used as long as the number and the packet can be uniquely associated.

  The buffer units 300B to 330B set and accumulate input packets as extraction targets in the order of input. Here, four buffer units are provided. However, any number of buffer units may be used.

  The transmission buffer allocating unit 400B performs a monitoring process by comparing the reception numbers assigned to the top packets stored in the buffer units 300B to 330B. Further, the transmission buffer allocating unit 400B performs extraction processing by sequentially extracting packets with the smallest reception number as a result of comparing the reception numbers.

  As to whether or not the discard counter is counted up, for example, the buffer units 300B to 330B send a packet transmission request to the transmission buffer allocating unit 400B and receive number assigned to the first packet stored by itself. Can be monitored.

  FIG. 10 is a schematic diagram illustrating an operation example of the communication control apparatus according to the second embodiment. With reference to FIG. 10, an operation example of the communication control apparatus according to the second embodiment will be described.

(Operation)
Here, as in the first embodiment, it is assumed that the reception buffer sorting unit 200 sorts and stores the received packets in the buffer unit in order by the round robin method. Also, the transmission buffer allocating unit 400B sequentially takes out packets by the round robin method. Here, it is assumed that the reception numbers are assigned to the packets in order from 0.

  The reception buffer distribution unit 200 performs a process of assigning a reception number to a packet that has received an input. In the example shown in FIG. 10, the fifth packet is discarded in the buffer unit 310B. In this case, after the fourth packet is extracted from the buffer unit 300B by the transmission buffer allocating unit 400B, the buffer unit 300B is eighth, the buffer unit 310B is ninth, the buffer unit 320B is sixth, and the buffer unit In 330B, the seventh packet is accumulated at the head.

  The transmission buffer allocating unit 400B performs extraction processing by sequentially extracting the packets with the smallest reception numbers as a result of comparing the reception numbers assigned to the top packets stored in the buffer units 300B to 330B. In the example shown in FIG. 10, since the reception number indicating the sixth is the smallest, the sixth packet is extracted from the buffer unit 320B.

(effect)
According to the second embodiment, even when a packet is discarded at the time of reception, the packet is transmitted in the order of the received packet.

(Third embodiment)
In the second embodiment, especially when the number of buffer units increases, the packet number comparison circuit of the transmission buffer allocation unit becomes complicated. The third embodiment shows a technique that does not complicate the transmission buffer allocator circuit.

  FIG. 11 is a schematic diagram illustrating a configuration example of a communication control apparatus according to the third embodiment. A configuration example of the communication control apparatus according to the third embodiment will be described with reference to FIG.

(Constitution)
A communication control unit 100C according to the third embodiment includes a reception buffer allocating unit 200, buffer units 300C to 330C, and a transmission buffer allocating unit 400C. The reception buffer distribution unit 200 has the same function as the reception buffer distribution unit 200 in the second embodiment.

  One of the buffer units 300C to 330C is a first buffer unit, and the other is a second buffer unit that accumulates packets to be extracted before packets accumulated in the first buffer unit. The first buffer unit notifies the second buffer unit of the reception number assigned to the first packet stored in the own buffer unit. The second buffer unit compares the reception number assigned to the first packet stored in its own buffer unit with the reception number notified from the first buffer unit.

  The transmission buffer allocating unit 400C performs the monitoring process by monitoring the result of comparison by the second buffer unit. In addition, when the transmission buffer allocating unit 400C performs the extraction process by sequentially extracting packets from a plurality of buffer units, if the reception number notified from the first buffer unit is smaller according to the result of the comparison, If it is determined, the extraction of the packet from the second buffer unit is skipped.

  The notification of the reception number can be notified, for example, if the first buffer unit presents the reception number assigned to the first packet stored by itself together with the packet transmission request to the second buffer unit. .

  For example, the second buffer unit may indicate that the reception number notified from the first buffer unit is smaller by not transmitting a packet transmission request to the transmission buffer allocating unit 400C. In this case, by transmitting a packet transmission request to the transmission buffer allocating unit 400C, it is possible to indicate that the reception number assigned to the first packet stored in the second buffer unit is smaller. In this way, the monitoring process can be performed by monitoring the result of the comparison by the second buffer unit in the transmission buffer allocating unit 400C.

  FIG. 12 is a schematic diagram illustrating an operation example of the communication control apparatus according to the third embodiment. With reference to FIG. 12, the operation example of the communication control apparatus which concerns on 3rd Embodiment is demonstrated.

(Operation)
Here, as in the second embodiment, it is assumed that the reception buffer allocating unit 200 sequentially allocates and accumulates packets in the buffer unit by the round robin method while assigning a reception number to the received packet. Also, the transmission buffer allocating unit 400B sequentially takes out packets by the round robin method. Here, it is assumed that the reception numbers are assigned to the packets in order from 0. Further, it is assumed that the first buffer unit is the buffer unit 320C and the second buffer unit is the buffer unit 310C.

  The reception buffer distribution unit 200 performs a process of assigning a reception number to a packet that has received an input. In the example shown in FIG. 12, the fifth packet is discarded in the buffer unit 310C. In this case, after the fourth packet is extracted from the buffer unit 300C by the transmission buffer allocating unit 400C, the buffer unit 300C is eighth, the buffer unit 310C is ninth, the buffer unit 320C is sixth, and the buffer unit In 330C, the seventh packet is accumulated at the head.

  The buffer unit 320C, which is the first buffer unit, notifies the buffer number 310C, which is the second buffer unit, of the reception number assigned to the top packet stored in the buffer unit. In the example shown in FIG. 12, since the sixth packet is accumulated in the first packet in the buffer unit 320C, the buffer unit 320C notifies the buffer unit 310C of the reception number indicating the sixth.

  The buffer unit 310C compares the reception number assigned to the first packet stored in the buffer unit with the reception number notified from the buffer unit 320C. In the example shown in FIG. 12, since the top packet stored in the buffer unit 310C is the ninth packet and the reception number notified from the buffer unit 320 is the sixth, the reception notified from the buffer unit 320C. The comparison result that the number is smaller is given.

  If the transmission buffer distribution unit 400C determines that the reception number notified from the buffer unit 320C is smaller, the transmission buffer distribution unit 400C skips extraction of the packet from the buffer unit 310C. In the example shown in FIG. 12, according to the above comparison result, the transmission buffer allocating unit 400C skips extraction of the ninth packet that is the first packet stored in the buffer unit 310C, and is stored in the buffer unit 320C. The sixth packet that is the first packet is extracted.

(effect)
With this method, even when a packet is discarded at the time of packet reception, the packet is transmitted in the order of the received packet.

(Modification of the third embodiment)
FIG. 13 is a schematic diagram illustrating a configuration example of a communication control apparatus according to a modification of the third embodiment. With reference to FIG. 13, a configuration example of a communication control apparatus according to a modification of the third embodiment will be described.

(Constitution)
The communication control unit 100D according to the modification of the third embodiment includes a reception buffer allocating unit 200, buffer units 300D to 330D, and a transmission buffer allocating unit 400C. The reception buffer distribution unit 200 and the transmission buffer distribution unit 400C have the same functions as the reception buffer distribution unit 200 and the transmission buffer distribution unit 400C in the third embodiment.

  One of the buffer units 300C to 330C is a first buffer unit, and the other is a second buffer unit that accumulates a packet to be extracted before a packet accumulated in the first buffer unit. One is a third buffer unit that accumulates packets to be extracted before packets accumulated in the second buffer unit. Similar to the third embodiment, the first buffer unit notifies the second buffer unit of the reception number assigned to the first packet stored in the buffer unit. In the third embodiment, each of the first buffer unit, the second buffer unit, and the third buffer unit is one, but a combination of the first buffer unit, the second buffer unit, and the third buffer unit. A plurality may exist.

  Similar to the third embodiment, the second buffer unit compares the reception number assigned to the first packet stored in the own buffer unit with the reception number notified from the first buffer unit. If it is determined from the comparison result that the reception number notified from the first buffer unit is smaller, the third buffer unit is notified of the reception number notified from the first buffer unit. Different from the third embodiment.

  The third buffer unit compares the reception number given to the first packet stored in the buffer unit with the reception number notified from the first buffer unit via the second buffer unit.

  FIG. 14 is a schematic diagram illustrating an operation example of the communication control apparatus according to the modification of the third embodiment. With reference to FIG. 14, the operation example of the communication control apparatus which concerns on the modification of 3rd Embodiment is demonstrated.

(Operation)
Here, as in the modification of the third embodiment, the reception buffer allocating unit 200 sequentially allocates and stores the packets in the buffer unit by the round robin method while assigning the reception number to the received packet. . In addition, the transmission buffer allocating unit 400C also sequentially extracts packets by the round robin method. Here, it is assumed that the reception numbers are assigned to the packets in order from 0. Further, it is assumed that the first buffer unit is the buffer unit 320D, the second buffer unit is the buffer unit 310D, and the third buffer unit is the buffer unit 300D.

  The reception buffer distribution unit 200 performs a process of assigning a reception number to a packet that has received an input. In the example shown in FIG. 14, the fifth packet is discarded in the buffer unit 310D. In this case, after the fourth packet is extracted from the buffer unit 300D by the transmission buffer allocating unit 400C, the buffer unit 300D is eighth, the buffer unit 310D is ninth, the buffer unit 320D is sixth, and the buffer unit In 330D, the seventh packet is accumulated at the head.

  The buffer unit 320D, which is the first buffer unit, notifies the buffer number 310D, which is the second buffer unit, of the reception number assigned to the first packet stored in the buffer unit. In the example illustrated in FIG. 14, since the sixth packet is accumulated in the first packet in the buffer unit 320D, the buffer unit 320D notifies the buffer unit 310D of the reception number indicating the sixth.

  The buffer unit 310D compares the reception number given to the first packet stored in the buffer unit with the reception number notified from the buffer unit 320D. In the example illustrated in FIG. 14, the first packet stored in the buffer unit 310D is the ninth packet, and the reception number notified from the buffer unit 320 is the sixth, so the reception notified from the buffer unit 320D is received. The comparison result that the number is smaller is given. The buffer unit 310D further notifies the buffer unit 300D of the reception number notified from the buffer unit 320D.

  If the transmission buffer distribution unit 400C determines that the reception number notified from the buffer unit 320 is smaller, the transmission buffer distribution unit 400C skips the extraction of the packet from the buffer unit 310. In the example illustrated in FIG. 14, according to the comparison result described above, the transmission buffer allocating unit 400C skips extraction of the ninth packet that is the first packet stored in the buffer unit 310D, and is stored in the buffer unit 320D. The sixth packet that is the first packet is extracted.

  The buffer unit 300D compares the reception number given to the first packet stored in the buffer unit with the reception number notified from the buffer unit 320D via the buffer unit 310D.

  According to the modification of the third embodiment, the packet order is maintained even when discarding occurs in a plurality of buffer units. In this case, when the arbitration between the buffer units is completed, only the buffer unit presenting the smallest number requests transmission to the transmission buffer allocation unit 400C, and the packet in the transmission buffer allocation unit 400C is transmitted. There is also an effect that arbitration by number comparison or round robin becomes unnecessary.

  According to the second and third embodiments, even when packet discarding occurs in the buffer unit, the order of transmission packets is not changed except for discarded packets. This is because the transmission buffer allocating unit is not a simple round robin operation. As a result, the receiving buffer allocating unit can also adopt a method other than allocating by round robin. For example, it is possible to select a buffer with the most margin based on the usage amount (empty capacity) of each buffer, the number of packets remaining in each buffer, and the like. The second and third embodiments can be applied as a method for selecting a buffer based on the amount of buffer used and the number of staying packets. Instead of the packet numbers shown in the second and third embodiments, the buffer usage and the number of staying packets may be applied.

  By applying this method and distributing packets in consideration of the state of each buffer, it is possible to expect an effect of reducing packet discard due to buffer congestion.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

It is a figure which shows the structural example of a general communication control apparatus (the 1). It is a figure which shows the structural example of a general communication control apparatus (the 2). It is a schematic diagram which shows the operation example in a common communication control apparatus (the 2). It is a schematic diagram which shows the operation example in a common communication control apparatus (the 2). It is a schematic diagram which shows the operation example in a common communication control apparatus (the 2). It is a schematic diagram which shows the operation example in a common communication control apparatus (the 2). It is a schematic diagram which shows the structural example of the communication control apparatus which concerns on 1st Embodiment. It is a schematic diagram which shows the operation example of the communication control apparatus which concerns on 1st Embodiment. It is a schematic diagram which shows the structural example of the communication control apparatus which concerns on 2nd Embodiment. It is a schematic diagram which shows the operation example of the communication control apparatus which concerns on 2nd Embodiment. It is a schematic diagram which shows the structural example of the communication control apparatus which concerns on 3rd Embodiment. It is a schematic diagram which shows the operation example of the communication control apparatus which concerns on 3rd Embodiment. It is a schematic diagram which shows the structural example of the communication control apparatus which concerns on the modification of 3rd Embodiment. It is a schematic diagram which shows the operation example of the communication control apparatus which concerns on the modification of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Communication control apparatus 200 Reception buffer distribution part 300-330 Buffer part 400 Transmission buffer distribution part 600 Communication control apparatus 700 Reception port distribution part 710 Reception buffer distribution part 800-890 Buffer part 900 Transmission port distribution part 910 Transmission Buffer distribution section

Claims (2)

A communication control device comprising a plurality of buffer units for setting and storing input packets in the order of extraction in the order of input,
A reception buffer distribution unit that receives input of a packet via one or a plurality of ports, and distributes and outputs the packet to the plurality of buffer units in order;
Extraction processing for extracting packets from the plurality of buffer units in the order in which the reception buffer allocating unit receives input based on the discard state, performing monitoring processing for monitoring packet discard states in the plurality of buffer units And a transmission buffer distribution unit that outputs the extracted packets in order ,
One of the plurality of buffer units is a first buffer unit, and the other is a second buffer unit that accumulates packets to be extracted before packets accumulated in the first buffer unit. ,
The reception buffer distribution unit
When receiving an input of a packet via one or a plurality of ports, a process of giving a reception number indicating the ordinal number of the received packet to the packet is further performed.
The first buffer unit includes:
Notifying the second buffer unit of the reception number given to the top packet stored in the buffer unit,
The second buffer unit includes:
A comparison is made between the reception number given to the first packet stored in the own buffer unit and the reception number notified from the first buffer unit,
The transmission buffer distribution unit
The monitoring process is performed by monitoring the comparison result, and when the extraction process is performed by sequentially extracting packets from the plurality of buffer units, the first buffer unit is notified of the comparison result. and when the operation determines that the received number is small is characterized by skipping extraction of packets from the second buffer unit, the communication control device. A communication control device comprising a plurality of buffer units for setting and storing input packets in the order of extraction in the order of input,
A reception buffer distribution unit that receives input of a packet via one or a plurality of ports, and distributes and outputs the packet to the plurality of buffer units in order;
Extraction processing for extracting packets from the plurality of buffer units in the order in which the reception buffer allocating unit receives input based on the discard state, performing monitoring processing for monitoring packet discard states in the plurality of buffer units And a transmission buffer distribution unit that outputs the extracted packets in order ,
One of the plurality of buffer units is a first buffer unit, and the other is a second buffer unit that accumulates a packet to be extracted before a packet that the first buffer unit accumulates. The other one is a third buffer unit for accumulating packets to be extracted before packets accumulated by the second buffer unit,
The reception buffer distribution unit
When receiving an input of a packet via one or a plurality of ports, a process of giving a reception number indicating the ordinal number of the received packet to the packet is further performed.
The first buffer unit includes:
Notifying the second buffer unit of the reception number given to the top packet stored in the buffer unit,
The second buffer unit includes:
A comparison is made between the reception number given to the first packet stored in the own buffer unit and the reception number notified from the first buffer unit,
If it is determined from the comparison result that the reception number notified from the first buffer unit is smaller, the reception number notified from the first buffer unit is set to the third buffer unit. Notify
The third buffer unit includes:
A comparison is made between the reception number given to the first packet stored in the own buffer unit and the reception number notified from the first buffer unit via the second buffer unit,
The transmission buffer distribution unit
The monitoring process is performed by monitoring the comparison result, and when the extraction process is performed by sequentially extracting packets from the plurality of buffer units, the first buffer unit is notified of the comparison result. and when the operation determines that the received number is small is characterized by skipping extraction of packets from the third buffer unit, a communication control device.

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