JP2013046389A - Packet transmitter, packet transmission method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce fluctuation regardless of the time of transmitting a real time packet.SOLUTION: A packet transmitter 10 includes a reception unit 40 for receiving packets and transferring the packets, a QoS classification section 61, and a transmission control section 64. The QoS classification section 61 classifies the packets transferred from the reception unit 40 into real time packets and non-real-time packets. The transmission control section 64 transmits the real time packets to a second transmission line 30 at a first time based on the time at which the real time packets are transferred by the reception unit 40. Also, the transmission control section 64 obtains a second time at which transmission of the non-real-time packets to the second transmission line 30 is completed beforehand. Then, the transmission control section 64 stops the transmission of the non-real-time packets when the second time is after the first time.

Description

  The present invention relates to a packet transmission device, a packet transmission method, and a program.

  In communication services represented by IP (Internet Protocol) telephone and streaming distribution of moving images, packets need to be transmitted and received in real time. However, since packets are generally transmitted via various devices, a delay is caused by this transmission. The delay time becomes longer or shorter depending on traffic conditions. Such fluctuation of the delay time is hereinafter simply referred to as fluctuation (jitter).

  Fluctuations often occur at transmission line interfaces where traffic is concentrated. In the transmission path interface, for example, after transmission of one packet is completed, another packet is transmitted. Therefore, when the size of the packet transmitted earlier is large, the packet transmitted later waits for a relatively long time. For this reason, a packet transmitted by a communication service having real-time properties (hereinafter referred to as a real-time packet) is affected by a packet transmitted first, and as a result, fluctuation occurs.

  Generally, it is desirable that the fluctuation of the real-time packet is small. For this reason, the technique which suppresses generation | occurrence | production of fluctuation is proposed (for example, refer patent document 1). The apparatus disclosed in Patent Literature 1 previously divides a packet transmitted by a communication service that does not have real-time properties (hereinafter referred to as a non-real-time packet) into a size that does not affect the time at which the real-time packet is transmitted. Thereby, since a real-time packet is transmitted at a predetermined time, fluctuations can be reduced.

JP 2002-016637 A

  Different points may be emphasized for fluctuation reduction depending on the communication service. For example, in an IP telephone, it is important to periodically transmit real-time packets while suppressing the occurrence of fluctuations and delays to some extent. Also, for example, in PTP (Precision Time Protocol), while a certain amount of delay is allowed, it is important to suppress the occurrence of fluctuations as much as possible. Note that PTP is a protocol for accurately determining the transmission delay between terminals in the order of sub-microseconds, and is defined in IEEE (The Institute of Electrical and Electronics Engineers) 1588.

  The device disclosed in Patent Document 1 has obtained the time at which the next real-time packet is transmitted based on the time at which one real-time packet is transmitted. As a result, real-time packets were periodically transmitted. However, when real-time packets are not necessarily transmitted periodically by communication services such as PTP, it has been difficult to reduce fluctuations in real-time packets.

  The present invention has been made in view of the above circumstances, and an object thereof is to reduce fluctuations regardless of the time at which a real-time packet is transmitted.

In order to achieve the above object, a packet transmission device according to the first aspect of the present invention provides:
Receiving means for receiving a packet from the first transmission path and transferring the received packet;
A classifying means for classifying the transferred packets into a real-time class to which a packet transmitted to the first transmission path by a predetermined communication service belongs, and a non-real-time class other than the real-time class;
First transmission means for starting transmission of packets classified into the real-time class to the second transmission path at a first time based on the time when the packet belonging to the real-time class is transferred by the reception means;
A second time at which transmission of packets classified into the non-real-time class to the second transmission line is completed is obtained in advance, and if the second time is later than the first time, the packet is classified into the non-real-time class. Stopping means for stopping transmission of the received packet;
Is provided.

In order to achieve the above object, a packet transmission device according to the second aspect of the present invention provides:
Receiving means for receiving a packet from the first transmission path and transferring the received packet;
A classifying means for classifying the transferred packets into a real-time class to which a packet transmitted to the first transmission path by a predetermined communication service belongs, and a non-real-time class other than the real-time class;
First transmission means for starting transmission of packets classified into the real-time class to a second transmission path at a first time based on the time when the packet belonging to the real-time class is received by the reception means;
A second time at which transmission of packets classified into the non-real-time class to the second transmission line is completed is obtained in advance, and if the second time is later than the first time, the packet is classified into the non-real-time class. Stopping means for stopping transmission of the received packet;
Is provided.

In order to achieve the above object, a packet transmission method according to a third aspect of the present invention includes:
A receiving step of receiving a packet from the first transmission path and transferring the received packet;
A classification step for classifying the transferred packet into a real-time class to which a packet transmitted to the first transmission path by a predetermined communication service belongs, and a non-real-time class other than the real-time class;
A first transmission step of starting transmission of a packet classified into the real-time class to a second transmission path at a first time based on a time when the packet belonging to the real-time class is transferred in the reception step;
A second time at which transmission of packets classified into the non-real-time class to the second transmission line is completed is obtained in advance, and if the second time is later than the first time, the packet is classified into the non-real-time class. A stop step for stopping transmission of the received packet;
including.

In order to achieve the above object, a program according to the fourth aspect of the present invention provides:
Computer
Receiving means for receiving a packet from the first transmission path and transferring the received packet;
A classifying means for classifying the transferred packet into a real-time class to which a packet transmitted to the first transmission path by a predetermined communication service belongs, and a non-real-time class other than the real-time class;
First transmission means for starting transmission of packets classified into the real-time class to the second transmission path at a first time based on the time when the packet belonging to the real-time class is transferred by the reception means;
A second time at which transmission of packets classified into the non-real-time class to the second transmission line is completed is obtained in advance, and if the second time is later than the first time, the packet is classified into the non-real-time class. Stop means for stopping transmission of received packets,
To function as.

  According to the present invention, a packet transmitted to a first transmission path by a predetermined communication service is transmitted to a second transmission path at a predetermined first time. In addition, when the second time when transmission of packets classified into the non-real-time class to the second transmission line ends is after the first time, transmission of packets classified into the non-real-time class is stopped. . Thereby, fluctuations can be reduced regardless of the time at which the real-time packet is transmitted.

It is a block diagram which shows the structure of the packet transmitter which concerns on embodiment. It is a flowchart which shows the process performed by the parameter setting part. (A) is a figure which shows the time when a packet is transferred by the receiving unit. (B) And (C) is a figure which shows the time when a transmission control part receives a packet. (A) is a figure which shows the time when a packet is transferred by the receiving unit. (B) And (C) is a figure which shows the time when a transmission control part receives a packet. It is a flowchart which shows the process performed by the transmission control part. It is a flowchart which shows the process by which a packet is transmitted in order of priority. It is a figure which shows the relationship between the time when transmission of a real-time packet is started, and the time when transmission of a non-real-time packet is completed. It is a figure which shows the relationship between the time when transmission of a real-time packet is started, and the time when transmission of a non-real-time packet is completed. (A) is a figure which shows the time when a packet is transferred by the receiving unit. (B) And (C) is a figure which shows the time when a packet is transmitted by the transmission control part. It is a figure which shows the time when a packet is transmitted by a transmission control part. It is a figure which shows the correspondence of a packet size, transmission rate, and transmission time. It is a figure which shows the hardware constitutions of a packet transmission apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the packet transmission device 10 according to the present embodiment is an interface device that receives an Ether packet from the first transmission path 20 and transmits it to the second transmission path 30. The first transmission path 20 is a transmission path that constitutes, for example, a LAN (Local Area Network). The second transmission path 30 is a transmission path that forms, for example, a WAN (Wide Area Network). The packet transmission device 10 includes a reception unit 40, a switch unit 50, a packet processing unit 60, a transmission IF (Interface) unit 70, a time management unit 80, and a parameter setting unit 90.

  The receiving unit 40 includes a first receiving unit 41 to an Nth receiving unit 43. The first receiver 41 to the Nth receiver 43 receive a packet from the first transmission path 20. For example, each of the first reception unit 41 to the Nth reception unit 43 receives a packet from each of a plurality of terminals connected to the first transmission path 20. Then, the first receiving unit 41 to the Nth receiving unit 43 transfer this packet to the switch unit 50.

  Further, the first receiver 41 to the Nth receiver 43 include a real-time packet discrimination circuit. The real-time packet discriminating circuit outputs a high-level signal when data indicating a real-time packet is included in the packet. The data indicating that it is a real-time packet is, for example, the value of the TOS (Type of Service) field of the IP packet included in the Ether packet. The receiving unit 40 includes an index for identifying a real-time packet based on the signal output from the real-time packet discriminating circuit and the current time notified from the time management unit 80, and the real-time packet is transmitted from the first receiver 41 to the first receiver The parameter transfer unit 90 is notified of the time transferred from the N receiving unit 43.

  The switch unit 50 routes the packets transferred from the first reception unit 41 to the Nth reception unit 43. For example, the switch unit 50 rewrites a destination MAC (Media Access Control) address included in the header of the packet. Then, the switch unit 50 transmits the packet to the packet processing unit 60.

  The packet processing unit 60 receives a packet from the switch unit 50, and classifies or divides the packet according to QoS (Quality of Service). The QoS in this embodiment is a high priority of the communication service that transmitted the packet. For example, the priority of a communication service that transmits real-time packets is set high in advance. The packet processing unit 60 includes a QoS classification unit 61, a buffer unit 62, a division unit 63, and a transmission control unit 64.

  The QoS classification unit 61 reads the data of the packet transmitted from the switch unit 50, and determines the communication service that transmitted this packet. Then, the QoS classification unit 61 classifies the packets into a plurality of classes based on the priority of the communication service. The QoS classification unit 61 according to the present embodiment classifies real-time packets into the first class, and classifies non-real-time packets into the second to fourth classes. Non-real-time packets are further classified into second, third, and fourth classes. Of the non-real-time packets, packets transmitted by a communication service with a high priority are classified into the second class, and packets transmitted by a communication service with a low priority are classified into a fourth class.

  For example, the QoS classification unit 61 reads the TOS field and the like of the packet. The QoS classification unit 61 transmits the packet transmitted by PTP or VoIP (Voice over Internet Protocol) to the first class, the packet transmitted by Telnet to the second class, and transmitted by FTP (File Transfer Protocol). Packets are classified into a third class, and packets transmitted by HTTP (Hypertext Transfer Protocol) are classified into a fourth class.

  Then, the QoS classification unit 61 transmits the first to fourth class packets to the buffer unit 62.

  The buffer unit 62 includes a first buffer 621, a second buffer 622, a third buffer 623, and a fourth buffer 624. Each of the first buffer 621 to the fourth buffer 624 stores the first to fourth class packets transmitted from the QoS classification unit 61, as shown in FIG. Each of the first buffer 621 to the fourth buffer 624 transmits the stored packet to the division unit 63.

  In addition, the buffer unit 62 notifies the parameter setting unit 90 of the state of the packet stored in each of the first buffer 621 to the fourth buffer 624. For example, the buffer unit 62 determines whether or not a packet is stored in each of the first buffer 621 to the fourth buffer 624 and notifies the parameter setting unit 90 of the determination result.

  The dividing unit 63 includes a first dividing unit 631, a second dividing unit 632, a third dividing unit 633, and a fourth dividing unit 634. Each of the first dividing unit 631 to the fourth dividing unit 634 receives the packets stored in the first buffer 621 to the fourth buffer 624, respectively.

  In addition, the division unit 63 acquires an instruction regarding division from the parameter setting unit 90. The instruction regarding the division is, for example, the size of the packet after division by each of the first division unit 631 to the fourth division unit 634 (hereinafter referred to as a fragment size). For example, the division unit 63 acquires an instruction to set the fragment size of the first division unit 631 to 9600 bytes. The fragment size is a value that is not less than a predetermined minimum size and does not exceed an MTU (Maximum Transmission Unit).

  Each of the first dividing unit 631 to the fourth dividing unit 634 divides a packet having a size larger than the fragment size to generate a plurality of packets. On the other hand, each of the first dividing unit 631 to the fourth dividing unit 634 does not divide a packet having a size equal to or smaller than the fragment size.

  Each of the first dividing unit 631 to the fourth dividing unit 634 transmits a plurality of packets (fragments) generated by this division to the transmission control unit 64 when the packet is divided. Also, each of the first dividing unit 631 to the fourth dividing unit 634 transmits the packet to the transmission control unit 64 when the packet is not divided.

  The transmission control unit 64 includes a first queue 641, a second queue 642, a third queue 643, and a fourth queue 644 that temporarily store packets. In each of the first queue 641 to the fourth queue 644, packets transmitted from the first dividing unit 631 to the fourth dividing unit 634 are stored.

  In addition, the transmission control unit 64 acquires the current time from the time management unit 80 and acquires information about the time at which the real-time packet is transmitted from the parameter setting unit 90. This information includes, for example, an index for identifying a real-time packet, a time when the real-time packet corresponding to this index is transferred from the receiving unit 40, and a fixed time Dc. The fixed time Dc is a time from when the real-time packet is transferred by the receiving unit 40 until it is transmitted by the transmission control unit 64, and is, for example, 1 microsecond. Based on this information, the transmission control unit 64 transmits a packet corresponding to the index among the packets stored in the first queue 641 to the transmission IF unit 70 at a predetermined time.

  In addition, the transmission control unit 64 acquires the transmission rate of the second transmission path 30 from the transmission IF unit 70. The transmission control unit 64 transmits the packets stored in the second queue 642 to the fourth queue 644 to the transmission IF unit 70 based on the transmission speed. At the time of this transmission, the transmission control unit 64 prioritizes the packet stored in the second queue 642 and then prioritizes the packet stored in the third queue 643.

  The transmission IF unit 70 is an interface circuit that sequentially transmits the packets transmitted from the transmission control unit 64 to the second transmission path 30. In addition, the transmission IF unit 70 notifies the transmission control unit 64 of the transmission speed of the second transmission path 30. The transmission speed of the second transmission path 30 is, for example, 1000 Mbps.

  The time management unit 80 notifies the reception unit 40, the parameter setting unit 90, and the transmission control unit 64 of the current time.

  The parameter setting unit 90 acquires the state of the packet stored in the first buffer 621 to the fourth buffer 624 from the buffer unit 62. The parameter setting unit 90 notifies the division unit 63 of an instruction regarding division based on this state.

  Further, the parameter setting unit 90 acquires the time at which the first reception unit 41 to the Nth reception unit 43 transferred the real-time packet and the index of the real-time packet from the reception unit 40. The parameter setting unit 90 stores a fixed time Dc in advance. The parameter setting unit 90 notifies the transmission control unit 64 of information including these indexes, time, and fixed time Dc.

  Next, the operation of the packet transmission device 10 having the above components will be described.

  First, the operation of the parameter setting unit 90 that notifies the division unit 63 of an instruction related to division based on the state of the packet stored in the buffer unit 62 will be described with reference to FIG.

  The parameter setting unit 90 determines whether or not a packet is stored in the first buffer 621 (step S101).

  When it is determined that the packet is stored in the first buffer 621 (step S101; Yes), the parameter setting unit 90 sets the fragment size of the second dividing unit 632 to the fourth dividing unit 634 to a predetermined small value. (Step S102). This value is, for example, 64 bytes.

  The parameter setting unit 90 notifies the set fragment size to the division unit 63 (step S103).

  The division by the division unit 63 that has received this notification will be described with reference to the example shown in FIG. As shown in FIG. 3A, the first class packet P11 is transferred by the receiving unit 40 at time T1. Further, the second class packet P20 is transferred at time T2, and the first class packet P12 is transferred at time T4.

  The time when the transmission control unit 64 receives these three packets when the division by the division unit 63 is not executed is shown in FIG. Specifically, the packet P11 is received at time T2 after the delay time D1 from time T1. The delay time D1 is the time required for routing by the switch unit 50 and classification by the QoS classification unit 61. Packet P20 is received at time Ta. The packet P12 is received at time Tc after the delay time D1 and the fluctuation amount J1 from time T4.

  When the packet P20 is divided by the division unit 63, the time when the transmission control unit 64 receives the packet is shown in FIG. Specifically, the packet P12 is received at time Tb after the delay time D1 and the fluctuation amount J2 from time T4. This fluctuation amount J2 is shorter than the fluctuation amount J1.

  Returning to FIG. 2, the parameter setting unit 90 returns to step S101 after step S103, and repeats the process.

  When it is determined that no packet is stored in the first buffer 621 (step S101; No), the parameter setting unit 90 determines whether a packet is stored in the second buffer 622 (step S104).

  When it is determined that the packet is stored in the second buffer 622 (step S104; Yes), the parameter setting unit 90 sets the fragment sizes of the third dividing unit 633 and the fourth dividing unit 634 to a predetermined small value. (Step S105). This value is, for example, 64 bytes.

  Next, the parameter setting unit 90 sets the fragment size of the second dividing unit 632 to a predetermined large value (step S106). This value is, for example, 9600 bytes. Then, the parameter setting unit 90 shifts the process to step S103.

  Here, the division of the division unit 63 notified of the fragment size set in steps S105 and S106 will be described using the example shown in FIG. As shown in FIG. 4A, the third class packet P30 is transferred by the receiving unit 40 at time Td. Also, the second class packet P20 is transferred at time Tf.

  FIG. 3B shows the time when the transmission control unit 64 receives these two packets when the division by the division unit 63 is not executed. Specifically, the packet P30 is received at a time Te after a delay time D1 from the time Td. The packet P20 is received at time Th, which is a delay time D2 after time Tf.

  When the packet P30 is divided by the dividing unit 63, the time when the transmission control unit 64 receives the packet is shown in FIG. Specifically, the packet P20 is received at time Tg after the delay time D3 from time Tf. This delay time D3 is shorter than the delay time D2.

  Returning to FIG. 2, when it is determined that the packet is not stored in the second buffer 622 (step S <b> 104; No), the parameter setting unit 90 determines whether the packet is stored in the third buffer 623. (Step S107).

  When it is determined that the packet is stored in the third buffer 623 (step S107; Yes), the parameter setting unit 90 sets the fragment size of the fourth division unit 634 to a predetermined small value (step S108). This value is, for example, 64 bytes.

  Next, the parameter setting unit 90 sets the fragment size of the third dividing unit 633 to a predetermined large value (step S109). This value is, for example, 9600 bytes. Then, the parameter setting unit 90 shifts the process to step S103.

  When it is determined that no packet is stored in the third buffer 623 (step S107; No), the parameter setting unit 90 determines whether a packet is stored in the fourth buffer 624 (step S110).

  When it is determined that the packet is stored in the fourth buffer 624 (step S110; Yes), the parameter setting unit 90 sets the fragment size of the fourth division unit 634 to a predetermined large value (step S111). This value is, for example, 9600 bytes. Then, the parameter setting unit 90 shifts the process to step S103.

  When it is determined that no packet is stored in the fourth buffer 624 (step S110; No), the parameter setting unit 90 returns to step S101 and repeats the process.

  Next, a process in which the transmission control unit 64 transmits a packet at a predetermined time based on the time when the real-time packet is transferred by the first reception unit 41 to the Nth reception unit 43 will be described with reference to FIG.

  First, the transmission control unit 64 determines whether or not a packet is stored in the first queue 641 (step S201). When it is determined that no packet is stored in the first queue 641 (step S201; No), the transmission control unit 64 executes transmission processing in order of priority (step S202). This process will be described with reference to FIG.

  First, the transmission control unit 64 determines whether or not a packet is stored in the second queue 642 (step S301). When it is determined that the packet is stored in the second queue 642 (step S301; Yes), the transmission control unit 64 transmits the packet stored in the second queue 642 (step S302). Thereafter, the transmission control unit 64 ends the process.

  When it is determined that no packet is stored in the second queue 642 (step S301; No), the transmission control unit 64 determines whether a packet is stored in the third queue 643 (step S303). When it is determined that the packet is stored in the third queue 643 (step S303; Yes), the transmission control unit 64 transmits the packet stored in the third queue (step S304). Thereafter, the transmission control unit 64 ends the process.

  When it is determined that no packet is stored in the third queue 643 (step S303; No), the transmission control unit 64 determines whether a packet is stored in the fourth queue 644 (step S305). When it is determined that the packet is stored in the fourth queue 644 (step S305; Yes), the transmission control unit 64 transmits the packet stored in the fourth queue 644 (step S306). Thereafter, the transmission control unit 64 ends the process.

  When it is determined that no packet is stored in the fourth queue 644 (step S305; No), the transmission control unit 64 ends the process.

  Returning to FIG. 5, the transmission control unit 64 that has completed the transmission processing in order of priority returns to Step S201 and repeats the processing.

  When it is determined in step S201 that the packet is stored in the first queue (step S201; Yes), the transmission control unit 64 calculates a time Tz at which the real-time packet stored in the first queue is transmitted. (Step S203). Specifically, the time Tz is calculated as the sum of the time Ty at which the real-time packet is transferred by the receiving unit 40 and a preset fixed time Dc.

  Next, the transmission control unit 64 determines whether or not a packet is stored in the second queue 642 (step S204). When it is determined that the packet is stored in the second queue 642 (step S204; Yes), the transmission control unit 64 starts when the packet stored in the second queue 642 is transmitted from the current time Tn. The end time of the transmission time is calculated. Then, the transmission control unit 64 determines whether or not the time Tz is before this end time (step S205).

  The determination in step S205 will be described using the examples shown in FIGS. The time Tn shown in FIGS. 7 and 8 is the time when the determination in step S205 is executed. Further, the packet P1 is a packet stored in the first queue 641, and the packet P2 is a packet stored in the second queue 642. Time Tz is a time at which transmission of the packet P1 is scheduled to start.

  When the packet P2 is transmitted from the time Tn, the transmission control unit 64 ends the transmission before the time Tz as shown in FIG. 7, or from the time Tz as shown in FIG. After that, it is determined whether this transmission is finished. Specifically, the transmission control unit 64 compares the time calculated using the expression Tn + S2 / Ve with the time Tz based on the size S2 of the packet P2 and the transmission speed Ve of the second transmission path 30. .

  Returning to FIG. 5, if the determination in step S205 is negative (step S205; No), the transmission control unit 64 transmits the packet stored in the second queue 642 (step S206). Thereafter, the transmission control unit 64 returns to step S203 and repeats the process.

  If the determination in step S205 is affirmative (step S205; Yes), the transmission control unit 64 stops transmitting the packet until time Tz and enters a standby state (step S207). Then, the packet stored in the first queue 641 is transmitted at time Tz (step S208). Thereafter, the transmission control unit 64 returns to step S201 and repeats the process.

  When it is determined that no packet is stored in the second queue 642 (step S204; No), the transmission control unit 64 determines whether a packet is stored in the third queue 643 (step S209). When it is determined that the packet is stored in the third queue 643 (step S209; Yes), the transmission control unit 64 starts when the packet stored in the third queue 643 is transmitted from the current time Tn. The end time of the transmission time is calculated. Then, the transmission control unit 64 determines whether or not the time Tz is before this end time (step S210).

  When the determination in step S210 is negative (step S210; No), the transmission control unit 64 transmits the packet stored in the third queue 643 (step S211). Thereafter, the transmission control unit 64 returns to step S203 and repeats the process.

  If the determination in step S210 is affirmative (step S210; Yes), the transmission control unit 64 proceeds to step S207.

  When it is determined that no packet is stored in the third queue (step S209; No), the transmission control unit 64 determines whether a packet is stored in the fourth queue 644 (step S212). When it is determined that the packet is stored in the fourth queue 644 (step S212; Yes), the transmission control unit 64 starts when the packet stored in the fourth queue 644 is transmitted from the current time Tn. The end time of the transmission time is calculated. Then, the transmission control unit 64 determines whether or not the time Tz is before this end time (step S213).

  When the determination in step S213 is negative (step S213; No), the transmission control unit 64 transmits the packet stored in the fourth queue 644 (step S214). Thereafter, the transmission control unit 64 returns to step S203 and repeats the process.

  If the determination in step S213 is affirmed (step S213; Yes), the transmission control unit 64 proceeds to step S207.

  If it is determined that no packet is stored in the fourth queue 644 (step S212; No), the transmission control unit 64 returns to step S201 and repeats the process.

  An example in which real-time packets are repeatedly transmitted by the transmission control unit 64 that executes the above processing will be described with reference to FIG.

  As shown in FIG. 9A, the first class packet P11 is transferred by the receiving unit 40 at time T1. Further, the first class packet P12 is transferred at time T4, and the first class packet P13 is transferred at time T7. Also, the second class packet P21, the third class packets P31 and P32, and the fourth class packet P41 are transferred at the time shown in FIG.

  FIG. 9B illustrates the time at which each packet is transmitted from the transmission control unit 64 when the division by the division unit 63 is not performed and the transmission control unit 64 does not control the time at which the real-time packet is transmitted. Show. At this time, the packet P11 is transmitted at a time after the delay time D1 from the time T1. The packet P12 is transmitted at the time Ti after the delay time D1 and the fluctuation amount J3 from the time T4. The packet P13 is transmitted at time T9 after the delay time D1 and the fluctuation amount J4 from time T7.

  FIG. 9C shows the time when each packet is transmitted from the transmission control unit 64 when the division by the division unit 63 is executed and the transmission control unit 64 controls the time when the real-time packet is transmitted. At this time, the packet P11 is transmitted at time T3, which is a fixed time Dc after time T1. The packet P12 is transmitted at time T6, which is a fixed time Dc after time T4. The packet P13 is transmitted at time T9, which is a fixed time Dc after time T7. That is, all of the packets P11, P12, and P13 are transmitted at a time Tz that is a fixed time Dc after the time Ty transferred by the receiving unit 40.

  As described above, the transmission control unit 64 according to the present embodiment transmits the real-time packet at the predetermined time Tz based on the time Ty when the real-time packet is transferred by the first reception unit 41 to the N-th reception unit 43. To do. Further, when the predetermined time Tz is before the end of the transmission of the non-real time packet, the transmission control unit 64 stops the transmission of the non-real time packet. Thereby, the real-time packet is transmitted at a predetermined time regardless of the time when the real-time packet is received. As a result, the occurrence of fluctuation can be suppressed.

  The transmission control unit 64 transmits the real-time packet at a time Tz that is a fixed time Dc after the time Ty at which the real-time packet is transferred by the first reception unit 41 to the Nth reception unit 43. As a result, the real-time packet is transmitted at a predetermined time independently of the time required for processing by the switch unit 50 and the packet processing unit 60.

  Further, the transmission control unit 64 calculates in advance the time during which the non-real time packet is transmitted based on the transmission rate of the second transmission path 30 and the size of the real time packet. Thereby, the packet transmission apparatus 10 can transmit packets to transmission paths having various transmission speeds while suppressing fluctuations.

  Further, the transmission control unit 64 sequentially transmits packets from the second class having higher priority among the second to fourth class non-real-time packets to which the priority is set. That is, the packet transmission device 10 preferentially transmits a packet transmitted by a predetermined communication service to the second transmission path. For example, the packet transmission device 10 can preferentially transmit a packet of a communication service with high responsiveness such as Telnet, over a communication service with low responsiveness such as HTTP. Thereby, the packet transmission apparatus 10 can improve the quality of various communication services.

  The first dividing unit 631 to the fourth dividing unit 634 divided the packet based on the fragment size notified from the parameter setting unit 90. As a result, the inconvenience caused by the transmission of a large-sized packet can be solved and the transmission efficiency can be prevented from lowering.

  For example, when the transmission control unit 64 controls the transmission time of the real-time packet without dividing the packet, the time when each packet is transmitted from the transmission control unit 64 is shown in FIG. As shown in FIG. 10, since transmission of the large-sized packet P41 and packet P32 is stopped, times E5 and E6 during which no packets are transmitted occur. As shown in FIG. 9C, when the packet is divided, times E3 and E4 during which the packet is not transmitted occur. These times E3 and E4 are shorter than the times E5 and E6. That is, the transmission efficiency can be improved by dividing the packet.

  Note that since a new header is added to each of the plurality of packets generated by the division, the data capacity after the division is larger than the data capacity before the division. For this reason, excessive division when division is not necessary generally reduces transmission efficiency. However, the parameter setting unit 90 adjusts the fragment size according to the status of the packets stored in the first buffer 621 to the fourth buffer 624. Thereby, the packet transmission apparatus 10 can prevent that transmission efficiency falls by excessive division | segmentation.

  Although the embodiment has been described above, the present invention is not limited to the above-described embodiment.

  For example, the receiving unit 40 according to the above embodiment notifies the parameter setting unit 90 of the time when the first receiving unit 41 to the Nth receiving unit 43 transferred the real-time packet. The receiving unit 40 may notify the parameter setting unit 90 of the time at which the first receiving unit 41 to the Nth receiving unit 43 received the real-time packet. In this case, the real-time packet is transmitted to the second transmission path 30 at a predetermined time independently of the time taken for the processing by the receiving unit 40.

  In addition, although the receiving unit 40 according to the above-described embodiment notifies the parameter setting unit 90 of the index of the real-time packet, the receiving unit 40 may be configured not to notify this index. In this case, the transmission control unit 64 sequentially transmits the packets stored in the first queue 641 based on the information notified from the parameter setting unit 90 without identifying the real-time packet.

  Moreover, although the QoS classification | category part 61 which concerns on the said embodiment classified the packet into the 1st class to which a real-time packet belongs, and the 2nd-4th class to which a non-real-time packet belongs, it is not restricted to this. For example, the packets may be classified into a plurality of classes to which real-time packets belong and four or more classes to which non-real-time packets belong.

  In the above embodiment, as an example, PTP and VoIP packets are classified into the first class, Telnet packets are classified into the second class, FTP packets are classified into the third class, and HTTP packets are classified into the fourth class. However, it is not limited to this. For example, the QoS classification unit 61 may be configured to classify FTP packets into the fourth class.

  Moreover, although the QoS classification | category part 61 which concerns on the said embodiment classified the packet based on the communication service, it is not restricted to this. For example, the packets may be classified based on an application, a process, a user, or a terminal ID including an IP address.

  In addition, the transmission control unit 64 according to the above embodiment calculates the time at which the transmission of the non-real-time packet ends based on the current time Tn at which the determinations at step S205, step S210, and step S213 are executed. The present time is not limited to this, and the current time Tn that takes into account the time taken from the start of these determinations to the transmission of the non-real-time packet may be used.

  In addition, the transmission control unit 64 according to the above-described embodiment transmits the real-time packet at the time Tz after the fixed time Dc after the time Ty when the real-time packet is transferred by the receiving unit 40. However, the transmission control unit 64 may adaptively change the time Dd between the time Ty and the time Tz at which the real-time packet is transmitted.

  For example, the transmission speed of the transmission path may vary depending on room temperature or temperature. In this case, the transmission control unit 64 may calculate a time Dd whose length varies with room temperature or the like, and transmit a real-time packet at a time later than the time Ty by this time Dd.

  In addition, among a plurality of terminals that transmit packets to the packet transmission device 10, there are cases where the transmission delay of packets transmitted from some terminals is significantly large or small. In this case, the time Dd may be adjusted based on the terminal that transmitted the real-time packet to eliminate the transmission delay imbalance between the terminals.

  The parameter setting unit 90 according to the above embodiment sets the fragment size to a predetermined value in step S102, step S105, step S106, step S108, step S109, and step S111. This value may be configured so that the administrator of the packet transmission device 10 can arbitrarily change the value.

  Moreover, although the packet transmission apparatus 10 according to the above-described embodiment functions as a relay apparatus for packets transmitted from the first transmission path to the second transmission path, the present invention is not limited to this. For example, the packet transmission device 10 may constitute a radio base station device. Further, another network device may be configured as the network interface.

  In addition, the transmission control unit 64 according to the above embodiment calculates the time during which the non-real-time packet is transmitted based on the transmission speed Ve of the second transmission path 30 and the size S2 of the non-real-time packet. Not limited. For example, a table representing the relationship between the transmission rate, the packet size, and the transmission time may be read from a storage device included in the packet transmission device 10 and the transmission time may be estimated based on this table.

  For example, when the transmission speed of the second transmission path 30 is 1000 Mbps and the packet size is 256 bytes, the transmission control unit 64 may obtain 2208 ns as the transmission time based on the table shown in FIG. Good. Note that the time shown in FIG. 11 includes a transmission interval corresponding to 12 bytes, and a transmission preamble and SFD (Start Frame Delimiter) transmission time corresponding to 8 bytes.

  In addition, the transmission control unit 64 according to the above embodiment transmits the packets stored in the second queue 642 to the fourth queue 644 in order from the packet belonging to the class having the higher priority. The transmission control unit 64 may execute priority control by CQ (Custom Queuing) or WFQ (Weighted Fair Queuing), not limited to so-called PQ (Priority Queuing).

  FIG. 12 is a block diagram illustrating a hardware configuration example when the packet transmission device 10 according to the above embodiment is mounted on a computer. The packet transmission device 10 can be realized by a hardware configuration similar to that of a general computer device. The packet transmission device 10 includes a processor H1, a main storage unit H2, an auxiliary storage unit H3, an output unit H4, an input unit H5, and a transmission / reception unit H6. The main storage unit H2, the auxiliary storage unit H3, the output unit H4, the input unit H5, and the transmission / reception unit H6 are all connected to the processor H1 via the internal bus H7.

  The processor H1 includes a CPU (Central Processing Unit) and the like, and executes the processes of the transmission control unit 64 and the parameter setting unit 90 according to the above-described embodiment according to a program H8 stored in the auxiliary storage unit H3.

  The main storage unit H2 includes a RAM (Random-Access Memory) or the like, loads a program H8 stored in the auxiliary storage unit H3, and is used as a work area for the processor H1.

  The auxiliary storage unit H3 includes a nonvolatile memory such as a flash memory, a hard disk, a DVD-RAM (Digital Versatile Disc Random-Access Memory), and a DVD-RW (Digital Versatile Disc ReWritable), and executes the above-described processing on the processor H1. Program H8 for communication, data of communication contents, and the like are stored. Further, the auxiliary storage unit H3 supplies the data stored in the program H8 to the processor H1 according to the instruction from the processor H1, and stores the data supplied from the processor H1.

  The output unit H4 includes a display device composed of an LCD (Liquid Crystal Display) or the like, an acoustic device or a printing device composed of a speaker or the like, and provides various information to the user. For example, the output unit H4 displays the traffic status to the administrator of the packet transmission device 10.

  The input unit H5 includes a pointing device such as a keyboard and a mouse, and an interface device that connects the keyboard and pointing device to the internal bus H7. For example, the user of the packet transmission device 10 sets a fragment size, a classified communication service, a fixed time Dc, and the like via the input unit H5.

  The transmission / reception unit H6 includes a modem or network termination device, and a serial interface or LAN interface connected thereto. The transmission / reception unit H6 physically implements the reception unit 40 and the transmission IF unit 70.

  Processing executed by the reception unit 40, the switch unit 50, the QoS classification unit 61, the buffer unit 62, the division unit 63, the transmission control unit 64, the time management unit 80, and the parameter setting unit 90 of the packet transmission device 10 illustrated in FIG. Is executed by processing the program H8 using the processor H1, the main storage unit H2, the auxiliary storage unit H3, the output unit H4, the input unit H5, the transmission / reception unit H6, and the like as resources.

  The function of the packet transmission device 10 according to the above-described embodiment can be realized by dedicated hardware or by a normal computer system.

  For example, the program H8 stored in the auxiliary storage unit H3 can be read by a computer such as a flexible disk, CD-ROM (Compact Disk Read-Only Memory), DVD (Digital Versatile Disk), and MO (Magneto-Optical disk). By storing and distributing in a recording medium and installing the program H8 in a computer, an apparatus that executes the above-described processing can be configured.

  Further, the program H8 may be stored in a disk device or the like included in a predetermined server device on a communication network such as the Internet, and may be downloaded onto a computer, for example, superimposed on a carrier wave.

  The above-described processing can also be achieved by starting and executing the program H8 while transferring it through the communication network.

  Further, the above-described processing can also be achieved by executing all or part of the program H8 on the server device and executing the program H8 while the computer transmits / receives information related to the processing via the communication network. .

  Note that when the above functions are realized by sharing an OS (Operating System) or when the functions are realized by cooperation between the OS and an application, only the part other than the OS may be stored in a medium and distributed. It may also be downloaded to a computer.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

(Appendix 1)
Receiving means for receiving a packet from the first transmission path and transferring the received packet;
A classifying means for classifying the transferred packets into a real-time class to which a packet transmitted to the first transmission path by a predetermined communication service belongs, and a non-real-time class other than the real-time class;
First transmission means for starting transmission of packets classified into the real-time class to the second transmission path at a first time based on the time when the packet belonging to the real-time class is transferred by the reception means;
A second time at which transmission of packets classified into the non-real-time class to the second transmission line is completed is obtained in advance, and if the second time is later than the first time, the packet is classified into the non-real-time class. Stopping means for stopping transmission of the received packet;
A packet transmission apparatus comprising:

(Appendix 2)
The first time is
A time after a predetermined time from the time when the packet belonging to the real-time class is transferred by the receiving means;
The packet transmission device according to attachment 1.

(Appendix 3)
The stopping means is
Obtaining the second time based on a current time, a size of the packet classified into the non-real-time class, and a transmission rate of the second transmission path;
The packet transmitter according to appendix 1 or 2.

(Appendix 4)
A second transmission means different from the first transmission means;
The classification means is
Classifying the forwarded packet into the real-time class and a plurality of non-real-time classes with priority set;
The second transmission means includes
Packets classified into the non-real-time class having a high priority are preferentially transmitted to the second transmission path.
The packet transmission device according to any one of supplementary notes 1 to 3.

(Appendix 5)
A plurality of storage means for storing packets classified into each of the plurality of non-real-time classes;
A plurality of dividing means for dividing a packet stored in each of the plurality of storage means;
Notification means for notifying each of the plurality of division means of the size of the packet generated by the division based on the state of the packet stored in each of the plurality of storage means;
With
The second transmission means includes
A packet output from the dividing unit corresponding to the non-real-time class having a high priority is preferentially transmitted to the second transmission path;
The packet transmitter according to appendix 4.

(Appendix 6)
Receiving means for receiving a packet from the first transmission path and transferring the received packet;
A classifying means for classifying the transferred packets into a real-time class to which a packet transmitted to the first transmission path by a predetermined communication service belongs, and a non-real-time class other than the real-time class;
First transmission means for starting transmission of packets classified into the real-time class to a second transmission path at a first time based on the time when the packet belonging to the real-time class is received by the reception means;
A second time at which transmission of packets classified into the non-real-time class to the second transmission line is completed is obtained in advance, and if the second time is later than the first time, the packet is classified into the non-real-time class. Stopping means for stopping transmission of the received packet;
A packet transmission apparatus comprising:

(Appendix 7)
A receiving step of receiving a packet from the first transmission path and transferring the received packet;
A classification step for classifying the transferred packet into a real-time class to which a packet transmitted to the first transmission path by a predetermined communication service belongs, and a non-real-time class other than the real-time class;
A first transmission step of starting transmission of a packet classified into the real-time class to a second transmission path at a first time based on a time when the packet belonging to the real-time class is transferred in the reception step;
A second time at which transmission of packets classified into the non-real-time class to the second transmission line is completed is obtained in advance, and if the second time is later than the first time, the packet is classified into the non-real-time class. A stop step for stopping transmission of the received packet;
Packet transmission method including:

(Appendix 8)
Computer
Receiving means for receiving a packet from the first transmission path and transferring the received packet;
A classifying means for classifying the transferred packet into a real-time class to which a packet transmitted to the first transmission path by a predetermined communication service belongs, and a non-real-time class other than the real-time class;
First transmission means for starting transmission of packets classified into the real-time class to the second transmission path at a first time based on the time when the packet belonging to the real-time class is transferred by the reception means;
A second time at which transmission of packets classified into the non-real-time class to the second transmission line is completed is obtained in advance, and if the second time is later than the first time, the packet is classified into the non-real-time class. Stop means for stopping transmission of received packets,
Program to function as.

DESCRIPTION OF SYMBOLS 10 Packet transmitter 20 1st transmission path 30 2nd transmission path 40 Reception unit 41 1st receiving part 42 2nd receiving part 43 Nth receiving part 50 Switch part 60 Packet processing unit 61 QoS classification part 62 Buffer unit 621 1st buffer 622 2nd buffer 623 3rd buffer 624 4th buffer 63 Dividing unit 631 1st dividing unit 632 2nd dividing unit 633 3rd dividing unit 634 4th dividing unit 64 Transmission control unit 641 1st queue 642 2nd queue 643 3rd Queue 644 Fourth queue 70 Transmission IF unit 80 Time management unit 90 Parameter setting unit P1, P2, P11, P12, P13, P20, P21, P30, P31, P32, P41 Packet S2 Size T1, T2, T3, T4, T5 , T6, T7, T8, T9, Ta, Tb, T , Td, Te, Tf, Tg, Th, Ti, Tj, Tn, Ty, Tz time Ve transmission rate

Claims (8)

Receiving means for receiving a packet from the first transmission path and transferring the received packet;
A classifying means for classifying the transferred packets into a real-time class to which a packet transmitted to the first transmission path by a predetermined communication service belongs, and a non-real-time class other than the real-time class;
First transmission means for starting transmission of packets classified into the real-time class to the second transmission path at a first time based on the time when the packet belonging to the real-time class is transferred by the reception means;
A second time at which transmission of packets classified into the non-real-time class to the second transmission line is completed is obtained in advance, and if the second time is later than the first time, the packet is classified into the non-real-time class. Stopping means for stopping transmission of the received packet;
A packet transmission apparatus comprising: The first time is
A time after a predetermined time from the time when the packet belonging to the real-time class is transferred by the receiving means;
The packet transmission device according to claim 1. The stopping means is
Obtaining the second time based on a current time, a size of the packet classified into the non-real-time class, and a transmission rate of the second transmission path;
The packet transmission device according to claim 1 or 2. A second transmission means different from the first transmission means;
The classification means is
Classifying the forwarded packet into the real-time class and a plurality of non-real-time classes with priority set;
The second transmission means includes
Packets classified into the non-real-time class having a high priority are preferentially transmitted to the second transmission path.
The packet transmission device according to any one of claims 1 to 3. A plurality of storage means for storing packets classified into each of the plurality of non-real-time classes;
A plurality of dividing means for dividing a packet stored in each of the plurality of storage means;
Notification means for notifying each of the plurality of division means of the size of the packet generated by the division based on the state of the packet stored in each of the plurality of storage means;
With
The second transmission means includes
A packet output from the dividing unit corresponding to the non-real-time class having a high priority is preferentially transmitted to the second transmission path;
The packet transmission device according to claim 4. Receiving means for receiving a packet from the first transmission path and transferring the received packet;
A classifying means for classifying the transferred packets into a real-time class to which a packet transmitted to the first transmission path by a predetermined communication service belongs, and a non-real-time class other than the real-time class;
First transmission means for starting transmission of packets classified into the real-time class to a second transmission path at a first time based on the time when the packet belonging to the real-time class is received by the reception means;
A second time at which transmission of packets classified into the non-real-time class to the second transmission line is completed is obtained in advance, and if the second time is later than the first time, the packet is classified into the non-real-time class. Stopping means for stopping transmission of the received packet;
A packet transmission apparatus comprising: A receiving step of receiving a packet from the first transmission path and transferring the received packet;
A classification step for classifying the transferred packet into a real-time class to which a packet transmitted to the first transmission path by a predetermined communication service belongs, and a non-real-time class other than the real-time class;
A first transmission step of starting transmission of a packet classified into the real-time class to a second transmission path at a first time based on a time when the packet belonging to the real-time class is transferred in the reception step;
A second time at which transmission of packets classified into the non-real-time class to the second transmission line is completed is obtained in advance. If the second time is later than the first time, the packet is classified into the non-real-time class A stop step for stopping transmission of the received packet;
Packet transmission method including: Computer
Receiving means for receiving a packet from the first transmission path and transferring the received packet;
A classifying means for classifying the transferred packet into a real-time class to which a packet transmitted to the first transmission path by a predetermined communication service belongs, and a non-real-time class other than the real-time class;
First transmission means for starting transmission of packets classified into the real-time class to the second transmission path at a first time based on the time when the packet belonging to the real-time class is transferred by the reception means;
A second time at which transmission of packets classified into the non-real-time class to the second transmission line is completed is obtained in advance, and if the second time is later than the first time, the packet is classified into the non-real-time class. Stop means for stopping transmission of received packets,
Program to function as.

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