JP2014003525A - Network control device, network control method, and network control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a network control device capable of transmitting packets so as to satisfy a set transmission rate for each QoS flow even when a number of QoS flows exist.SOLUTION: A network control device comprises: identification means for identifying a QoS flow number on the basis of a content of a transmission target packet; calculation means for calculating delay time by a predetermined method on the basis of the QoS flow number; storage means for storing a transmission packet according to each scheduled transmission time range; and transmission means for calculating scheduled transmission time of the transmission target packet by adding the delay time to the current time, storing the transmission target packet in the storage means as the transmission packet in association with the scheduled transmission time range including the scheduled transmission time, and transmitting the transmission packet stored in the storage means in association with the scheduled transmission time range including the scheduled transmission time when the scheduled transmission time has come.

Description

  The present invention relates to a network control device, a network control method, and a network control program, and more particularly, to a network control device, a network control method, and a network control program that realize QoS shaping processing.

  Edge router devices (routers located at the boundary between one network and another network) and 3GPP (Third) for ISPs (Internet Service Providers; refer to Internet providers, also referred to as “providers”) on the Internet Abbreviation for Generation Partnership Project, which refers to the 3G mobile phone (3G) standardization project, or the standard for mobile communication systems by the project.) In the node equipment on the core network of the mobile network, Depending on the contract status, communication status, etc., the transmission rate (transmission timing) may need to be restricted for each user. For this reason, a large number of accommodated users (QoS (Quality) An abbreviation for “of Service.” A technique for reserving a band for a specific communication on a network and guaranteeing a constant communication speed.) Flow) A QoS shaping process may be applied to each unit. The QoS shaping process is a process of transmitting data with a delay necessary for accurately keeping a preset transmission rate.

  A configuration of a general IP router is shown in FIG.

  In FIG. 5, the IP router includes a packet processing processor, a plurality of transmission side and reception side ports, and a plurality of transmission side and reception side PHY / MAC devices. The packet processing processor has means 501 to 505 and a received packet storage memory 510. A PHY (abbreviation of PHYsical layer) device performs D / A conversion corresponding to the physical layer, and a MAC (abbreviation of Media Access Control) device is a frame (data transmission / reception) corresponding to a lower sublayer of the data link layer. Unit).

  The packet receiving unit 501 receives a packet input from each port, stores the received packet in the received packet storage memory 510, and then checks the end of the Ether header and the IP header. The reception-side QoS means 502 performs QoS processing such as policing when limiting the reception rate. The routing search means 503 searches for a destination port or next hop destination based on the IP address included in the IP header. The transmission side QoS means 504 performs QoS processing such as shaping when limiting the transmission rate. The packet transmission unit 505 adds an Ether header and transmits the packet to the transfer destination port.

  5 may be realized by a program or task executed by a general computer, or may be realized by dedicated hardware.

  One function of the IP router is shown in FIG.

  The flow identification unit 601 and the plurality of queue memories 602 correspond to the transmission side QoS unit 504. When applying the QoS shaping process, the queue memory 602 is prepared in units of QoS flows # 1 to n (n is an integer of 2 or more). Based on the packet information received from the routing search unit 503, the flow identification unit 601 determines which QoS flow queue memory 602 queues the packet, and stores the packet in the determined queue memory 602.

  The QoS flow number is generally specified by extracting a source address and a destination address included in an IP header of a packet, a source port number and a destination port number included in a TCP / UDP header, and the like.

  When the packet is stored in all the queue memories 602 and the packet cannot be queued any more, the flow identification unit 601 discards a new incoming packet without queuing.

  The packet transmission unit 603 polls each queue memory 602 in a predetermined order, extracts packets according to the transmission rate set for each QoS flow, and transmits the packets to the transmission device. Through a series of these processes, the packet is transmitted according to the transmission rate set for each QoS flow.

  6 may be realized by a program or task executed on a general computer, or may be realized by dedicated hardware.

  Patent Document 1 describes a data communication system that enables a delay time for a packet to be quantitatively and dynamically controlled.

  In the data communication system described in Patent Literature 1, the delay time is calculated based on the maximum delay time designated by the packet transmission source, the average transfer rate of the communication path, and the number of communication control devices. Then, based on the delay time calculated in this way, the packets are arranged in the transmission queue in the order of transmission, and when the transmission time comes, the packets are sequentially extracted from the first packet and transmitted.

JP-A-11-243420

  In the transmission side processing of the IP packet routing function shown in FIG. 6, a queue memory is allocated for each QoS flow. Therefore, when there are many QoS flows to be applied, it is necessary to prepare a large amount of queue memory 602.

  The packet transmission unit 603 polls the queue memory 602 in a predetermined order, and extracts packets in accordance with the transmission rate set for each QoS flow. When a large amount of queue memory 602 is mounted as described above, the packet transmission unit 603 takes time to finish polling all the queue memories. As a result, each queue memory has its The time interval until the next polling order comes around becomes longer. For this reason, in a certain queue memory 602, even when a packet must be taken out from the queue memory, the polling order does not come to the queue memory, and the packet transmission means 603 cannot take out the packet. A situation may arise.

  In that case, there is a problem that the packet transmission means 603 is forced to transmit packets at a rate lower than the set transmission rate.

  Further, as described above, Patent Document 1 only discloses a technique in which a data transmission source designates a maximum delay time and performs data transmission within the designated maximum delay time, and a designated accurate transmission rate. No technology for transmitting data (packets) is disclosed.

  An object of the present invention is to provide a network control device, a network control method, and a network control program that solve the above-described problems.

  The network control apparatus of the present invention includes an identification unit that identifies a QoS flow number based on the contents of a packet to be transmitted, a calculation unit that calculates a delay time by a predetermined method based on the QoS flow number, and each transmission schedule Storage means for storing transmission packets corresponding to a time range; and adding the delay time to a current time to obtain a transmission scheduled time of the transmission target packet, and corresponding to the transmission scheduled time range including the transmission scheduled time The transmission target packet is stored in the storage unit as the transmission packet, and when the scheduled transmission time arrives, the transmission packet stored in the storage unit is transmitted in association with the scheduled transmission time range including the scheduled transmission time And transmitting means.

  The network control method of the present invention includes an identification step of identifying a QoS flow number based on the content of a packet to be transmitted, a calculation step of calculating a delay time by a predetermined method based on the QoS flow number, and the delay time The transmission scheduled time determination step for obtaining the transmission scheduled time of the transmission target packet in addition to the current time, and the storage means for storing the transmission packet corresponding to each scheduled transmission time range in the transmission time determination step An accumulation step of accumulating the transmission target packet as the transmission packet in correspondence with the scheduled transmission time range including the scheduled transmission time, and corresponding to the planned transmission time range including the scheduled transmission time when the scheduled transmission time arrives Transmitting the transmission packet stored in the storage means.

  The network control program of the present invention includes an identification process for identifying a QoS flow number based on the contents of a packet to be transmitted, a calculation process for calculating a delay time by a predetermined method based on the QoS flow number, and the delay time. In addition to the current time, the scheduled transmission time determination process for determining the scheduled transmission time of the transmission target packet, and the storage means for storing the transmission packet corresponding to each scheduled transmission time range, the transmission time determined in the transmission time determination step An accumulation process for accumulating the transmission target packet as the transmission packet in correspondence with the transmission scheduled time range including the transmission scheduled time, and corresponding to the transmission scheduled time range including the transmission scheduled time when the transmission scheduled time arrives And causing the computer to execute transmission processing for transmitting the transmission packet stored in the storage means.

  As described above, the present invention has an effect that even when there are a large number of QoS flows, packets can be transmitted so as to satisfy the transmission rate set for each QoS flow.

It is a block diagram of a 1st embodiment of the present invention. It is a figure which shows the Token Bucket database memory 121 in the 1st Embodiment of this invention. It is a flowchart which shows the processing flow of the delay calculation means 120 in the 1st Embodiment of this invention. It is a figure which shows the transmission time slot memory 131 in the 1st Embodiment of this invention. It is a block diagram which shows the structure in a common IP router. It is a block diagram which shows one function of a general IP router.

  Next, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a first embodiment of the present invention.

  Referring to FIG. 1, the network control apparatus 100 according to this embodiment includes a flow identification unit 110, a delay calculation unit 120, a token bucket database memory 121, a delay transmission unit 130, and a transmission time slot memory 131. Has been.

  Each of the means 110, 120, and 130 may be realized by a program or task executed by a general computer, or may be realized by dedicated hardware.

  This embodiment replaces the configuration of a part of a general IP router as shown in FIG.

  The flow identification unit 110, the delay calculation unit 120, and the Token Bucket database memory 121 replace a part of the configuration of the transmission side QoS unit 504 in FIG.

  The delay transmission unit 130 and the transmission time slot memory 131 replace a part of the configuration of the packet transmission unit 505 in FIG.

  Here, the packet to be processed has already been stored in the received packet storage memory 510 by the packet receiving means 501 in FIG. The head address of the process target packet in the received packet storage memory 510 is referred to as packet information. The flow identification unit 110, the delay calculation unit 120, and the delay transmission unit 130 refer to the processing target packet in the received packet storage memory 510 based on the packet information.

  The flow identification unit 110 receives from the routing search unit 503 the packet information of the packet determined by the destination interface by the routing search unit 503 in FIG.

  The flow identification unit 110 identifies the QoS flow number based on the received packet information.

  After identifying the QoS flow number, the flow identifying unit 110 transmits the packet information and the QoS flow number information to the delay calculating unit 120.

  The delay calculation unit 120 calculates a delay time to be given when a packet is transmitted, using the Token Bucket algorithm.

  As will be described later, the delay calculation unit 120 includes a parameter group corresponding to the QoS flow number received from the flow identification unit 110 from among a plurality of parameter groups necessary for the Token Bucket calculation set in the Token Bucket database memory 121. To calculate the delay time.

  The delay calculation unit 120 transmits the calculated delay time and packet information to the delay transmission unit 130.

  The delay transmission unit 130 copies the processing target packet in the reception packet storage memory 510 to the transmission packet storage memory 132 based on the packet information received from the delay calculation unit 120.

  The delay transmission unit 130 stores the start address of the processing target packet copied to the transmission packet storage memory 132 in the transmission time slot memory 131 based on the delay time received from the delay calculation unit 120.

  The delay transmission means 130 extracts the packet information from the transmission time slot memory 131 after the designated delay time has elapsed, and instructs the transmission device to transmit the packet.

  Next, the operation of this embodiment will be described in detail.

  Based on the received packet information, the flow identification unit 110 refers to the processing target packet in the received packet storage memory 510 and identifies the QoS flow number.

  The QoS flow number is generally specified by extracting a source address and a destination address included in an IP header of a packet, a source port number and a destination port number included in a TCP / UDP header, and the like.

  After identifying the QoS flow number, the flow identification unit 110 transmits the packet information and the QoS flow number information to the delay calculation unit 120.

  The delay calculation means 120 calculates a delay time set in the transmission packet by the Token Bucket algorithm.

  The delay calculation unit 120 refers to the Token Bucket database memory 121, acquires parameters necessary for calculation based on the received QoS flow number, and calculates a delay time.

  FIG. 2 shows the contents of the Token Bucket database memory 121.

  The Token Bucket database memory 121 has a transmission rate value (An), a maximum Token value (Bn), a current Token value (Cn), and a previous Token replenishment time (Dn) for each QoS flow number.

  The transmission rate value is a rate (unit: bps (bit per second)) at which shaping is applied, and corresponds to the supplement rate of Token. This parameter must be set in advance.

  The maximum Token value is a parameter related to the maximum allowable delay time, and indicates the maximum size (unit: bit) that Token can replenish. This parameter must be set in advance.

  The current Token value indicates the current Token size (unit: bit). The maximum Token value is set as an initial value for this parameter, and the value is updated each time a packet passes. The current Token value is incremented by the Token size to be replenished when Token is replenished. On the other hand, when Token is consumed, the size is subtracted by the transmission packet size.

  The previous Token replenishment time is the time when the previous packet replenished the Token of the corresponding QoS flow. Every time Token is replenished, this time is updated.

  The delay time calculation performed by the Token Bucket algorithm using these parameters (transmission rate, maximum Token value, current Token value, and previous Token supplement time) will be described with reference to FIG.

  The delay calculating unit 120 refers to each value in the memory 121 corresponding to the QoS flow number (for example, #n) received from the flow identifying unit 110, and sets the size of the token to be supplemented as follows. Calculation is performed using an equation (step S1).

Size of Token to be replenished ← (current time (Cn) −previous Token replenishment time (Dn)) × transmission rate (An)
The delay calculation means 120 adds the Token size calculated here to the current Token value (Cn), and stores it in the memory 121 as a new current Token value (Cn) (step S2).

  Further, the delay calculation means 120 updates the previous Token supplement time (Dn) in the memory 121 to the current time (step S3).

  If the new current Token value (Cn) after addition in step S2 is smaller than the maximum Token value (Bn) and the Token (Cn) value is smaller than the transmission packet size, the Token value necessary for transmission is sufficient. Therefore, a delay longer than the maximum delay time will occur. Therefore, the delay calculation means 120 changes the Token value (Cn) and the previous Token replenishment time (Dn) in the memory 121 to the values before the change (steps S2 and S3) (step S6), without transmitting a packet. Discard and end the process (step S7).

  If the Token value (Cn) after the addition in Step 2 is equal to or greater than the maximum Token value (Bn), the delay calculation means 120 sets the current Token value (Cn) to the same value as the maximum Token value (Bn) (Step S4), the delay time is set to 0 (step S5). Thereafter, the process proceeds to step S9 described later.

  On the other hand, when the new current Token value (Cn) after the addition in step S2 is smaller than the maximum Token value (Bn) and the Token (Cn) value is equal to or larger than the transmission packet size, the delay calculation unit 120 The delay time is calculated by the following formula (step S8).

Delay time ← (Maximum Token value (Bn) −Current Token value (Cn)) ÷ Transmission rate (An)
After calculating the delay time, the delay calculation unit 120 subtracts the transmission packet size from the current Token value (Cn), and stores the result in the memory 121 as a new current Token value (Cn) (step S9).

  Next, the delay calculation means 120 transmits packet information and delay time information to the delay transmission means 130 for packets other than those determined to be discarded (step S10).

  Next, the delay transmission unit 130 will be described.

  The delay transmission means 130 stores the transmission packet information in the transmission time slot memory 131, identifies the packet that has reached the scheduled transmission time with reference to the transmission time slot memory 131, and specifies the packet in a transmission packet storage memory to be described later. Two processes of taking out from 132 and transmitting are alternately performed.

  First, processing for storing transmission packet information in the transmission time slot memory 131 will be described.

  Before explaining this process, the transmission time slot memory 131 and the transmission packet storage memory 132 used for the process will be described with reference to FIG.

  The transmission time slot memory 131 is configured as shown in FIG. The memory 131 includes a time slot column 410 indicating a packet transmission scheduled time range (also referred to as “time slot”) (time slots T0 to Tx), and address information of packets to be transmitted in each time slot (T0 to Tx). The address information column 420 stores the address.

  The portion corresponding to each time slot (T0 to Tx) in the address information column 420 is composed of two entries: a packet data head address storage unit 421 at the head of the list and a packet data head address storage unit 422 at the end of the list.

  The packet data head address storage unit 421 at the head of the list is an area for storing the head address in the storage memory 132 of the transmission packet to be transmitted first in each time slot.

  The packet data head address storage unit 422 at the end of the list is an area for storing the head address in the storage memory 132 of the transmission packet to be transmitted last in each time slot.

  Next, the transmission packet data 431 in the transmission packet storage memory 132 referred to from each address (421 and 422) in the address information column will be described.

  Each transmission packet data 431 includes a transmission packet data part and a next transmission packet data head address part 432.

  In the next transmission packet data head address portion 432, when there is a packet to be transmitted continuously after a certain packet, the head address in the storage memory 132 of the packet to be transmitted next is set.

  Next, as described above, processing for storing transmission packet information in the transmission time slot memory 131 will be described.

  First, the delay transmission unit 130 copies the processing target packet in the reception packet storage memory 510 as transmission packet data 431 in the transmission packet storage memory 132 based on the packet information received from the delay calculation unit 120.

  Next, the delay transmission means 130 adds the delay time received from the delay calculation means 120 to the current time to calculate the scheduled transmission time.

  Further, the delay transmission means 130 checks which time slot T0 to Tx in the time slot column of the transmission time slot memory 131 corresponds to the calculated scheduled transmission time.

  For example, when the scheduled transmission time is included in the time range indicated by the time slot T0, the time slot T0 is applicable.

  Hereinafter, a case where the scheduled transmission time corresponds to the time slot T0 will be described as an example.

  If no address is set in the storage unit 421 corresponding to the time slot T0 in the time slot column 410 of the transmission time slot memory 131, one packet to be transmitted during the time slot T0 is stored in the transmission packet storage memory 132. Indicates that it is not registered. In this case, the delay transmission unit 130 sets the head address of the transmission packet data 431 previously copied to the memory 132 in the storage units 421 and 422 corresponding to the time slot T0 in the memory 131.

  If the address has already been set in the storage unit 421 corresponding to the time slot T0 in the time slot column 410 in the transmission time slot memory 131, the packet to be transmitted during the time slot T0 has already been transmitted. It is registered in the storage memory 132. In this case, the delay transmission means 130 additionally registers the information of the transmission packet at the end of the already registered packet.

  Specifically, when the delay transmission means 130 confirms that the head address of the transmission packet data # 0 is stored in the storage unit 421 corresponding to the time slot T0 in the time slot column 410 in the memory 131, the time slot 130 The transmission packet data #m in the transmission packet storage memory 132 is referenced based on the head address of the last transmission packet data #m stored in the storage unit 422 corresponding to T0, and the next transmission in the transmission packet data #m In the packet data head address portion, the head address of the transmission packet copied earlier is set. Thereafter, the delay transmission unit 130 sets the same address in the storage unit 422 corresponding to the time slot T0.

  Next, a description will be given of processing for extracting and transmitting a packet that has passed the specified delay time from the transmission time slot memory 131.

  The delay transmission means 130 refers to a time slot including the current time in the time slot column 410 of the transmission time slot memory 131 in order to determine whether there is a transmission target packet.

  Hereinafter, a case where the current time is included in the time slot T1 will be described as an example.

  If an address is set in the storage unit 421 corresponding to the time slot T1 in the time slot column 410 of the transmission time slot memory 131, this means that there is data to be transmitted. The delay transmission means 130 extracts the content of the transmission packet data portion in the transmission packet storage memory 132 specified by the address and the content of the next transmission packet data head address portion 432, and the content of the transmission packet data portion is sent to the transmission device. The packet transmission process is performed.

  If the address is set as the content of the next transmission packet data head address portion 432 that has been taken out, the delay transmission means 130 stores the transmission packet data portion in the transmission packet storage memory 132 specified by the address. The contents and the contents of the next transmission packet data head address part 432 are taken out, the contents of the transmission packet data part are sent to the transmission device, and packet transmission processing is performed.

  The delay transmission means 130 transmits all the transmission packets to be transmitted during the time slot T1 by repeating these processes while the address is set in the next transmission packet data head address portion 432.

  If no address is set in the storage unit 421 corresponding to the time slot T1 in the time slot column 410 of the transmission time slot memory 131, the packet to be transmitted does not exist. The process of sending is not performed.

  In this embodiment, the delay time is calculated using the Token Bucket algorithm. However, if a delay time that can satisfy the transmission rate set for each QoS flow can be obtained, it may be calculated using another algorithm. .

  In the present embodiment, the router may be realized by dedicated hardware or a general computer.

  As described above, this embodiment has an effect that packets can be transmitted so as to satisfy the transmission rate set for each QoS flow.

  The reason is that the process of transmitting the transmission target packet is not affected by the number of QoS flows by accumulating the transmission target packet for each scheduled transmission time range instead of the QoS flow unit.

DESCRIPTION OF SYMBOLS 100 Network control apparatus 110 Flow identification means 120 Delay calculation means 121 Token Bucket database memory 130 Delay transmission means 131 Transmission time slot memory 132 Transmission packet storage memory 410 Time slot column 420 Address information column 421 List data top address storage unit 422 Packet data head address storage section at the end of the list 431 Transmission packet data 432 Next transmission packet data head address section 501 Packet reception means 502 Reception side QoS means 503 Routing search means 504 Transmission side QoS means 505 Packet transmission means 510 Reception packet storage memory 601 Flow Identification means 602 Queue memory 603 Packet transmission means

Claims (10)

An identification means for identifying a QoS flow number based on the content of the packet to be transmitted;
Calculation means for calculating a delay time by a predetermined method based on the QoS flow number;
Storage means for storing transmission packets corresponding to each scheduled transmission time range;
The delay time is added to the current time to obtain the scheduled transmission time of the transmission target packet, and the transmission target packet is stored in the storage unit as the transmission packet in correspondence with the planned transmission time range including the transmission scheduled time. Transmitting means for transmitting the transmission packet stored in the storage means in correspondence with the scheduled transmission time range including the scheduled transmission time when the scheduled transmission time arrives;
A network control apparatus comprising: The storage means includes
Corresponding to each of the scheduled transmission time ranges, a leading packet address storage unit that stores a leading address of a storage region of a transmission packet to be transmitted first and a trailing packet address storage unit that stores a leading address of a storage region of a transmission packet to be transmitted last A time slot memory provided with
Packet storage means for storing a pair of a transmission packet and a start address of a storage area of a transmission packet to be transmitted next to the transmission packet in correspondence with each of the transmission scheduled time ranges,
The network control apparatus according to claim 1, further comprising: The transmission means includes
Transmitting a transmission packet to be transmitted first designated by a head address stored in the head packet address storage unit provided corresponding to the scheduled transmission time range including the current time, and then pairing with the transmission packet; By repeating the operation of transmitting the transmission packet specified by the head address stored in the storage means in the transmission packet as long as the head address stored in the packet storage means exists, the current packet The network control apparatus according to claim 2, wherein all transmission packets to be transmitted are transmitted within the scheduled transmission time range including a time.   4. The network control apparatus according to claim 1, wherein the predetermined method used by the calculation means is a Token Bucket algorithm. An identification step for identifying a QoS flow number based on the content of the packet to be transmitted;
A calculation step of calculating a delay time by a predetermined method based on the QoS flow number;
A scheduled transmission time determination step for obtaining a transmission scheduled time of the transmission target packet by adding the delay time to the current time;
In the storage means for storing the transmission packet corresponding to each scheduled transmission time range, the transmission target packet is set as the transmission packet in association with the planned transmission time range including the planned transmission time obtained in the transmission time determining step. An accumulation step to accumulate;
And a transmission step of transmitting the transmission packet stored in the storage means in correspondence with the transmission scheduled time range including the transmission scheduled time when the transmission scheduled time arrives. The storage means includes
Corresponding to each of the scheduled transmission time ranges, a leading packet address storage unit that stores a leading address of a storage region of a transmission packet to be transmitted first and a trailing packet address storage unit that stores a leading address of a storage region of a transmission packet to be transmitted last A time slot memory provided with
Packet storage means for storing a pair of a transmission packet and a start address of a storage area of a transmission packet to be transmitted next to the transmission packet in correspondence with each of the transmission scheduled time ranges,
The network control method according to claim 5, further comprising: In the transmission step,
Transmitting a transmission packet to be transmitted first designated by a head address stored in the head packet address storage unit provided corresponding to the scheduled transmission time range including the current time, and then pairing with the transmission packet; By repeating the operation of transmitting the transmission packet specified by the head address stored in the storage means in the transmission packet as long as the head address stored in the packet storage means exists, the current packet The network control method according to claim 6, wherein all transmission packets to be transmitted are transmitted within the scheduled transmission time range including a time. An identification process for identifying a QoS flow number based on the content of the packet to be transmitted;
A calculation process for calculating a delay time by a predetermined method based on the QoS flow number;
A scheduled transmission time determination process for determining the scheduled transmission time of the transmission target packet by adding the delay time to the current time;
In the storage means for storing the transmission packet corresponding to each scheduled transmission time range, the transmission target packet is set as the transmission packet in association with the planned transmission time range including the planned transmission time obtained in the transmission time determining step. Accumulation processing to accumulate,
A network control program for causing a computer to execute a transmission process of transmitting the transmission packet stored in the storage means in correspondence with the transmission scheduled time range including the transmission scheduled time when the transmission scheduled time arrives . The storage means includes
Corresponding to each of the scheduled transmission time ranges, a leading packet address storage unit that stores a leading address of a storage region of a transmission packet to be transmitted first and a trailing packet address storage unit that stores a leading address of a storage region of a transmission packet to be transmitted last A time slot memory provided with
9. The packet storage means for storing a pair of a packet to be transmitted and a start address of a storage area of a transmission packet to be transmitted next to the transmission packet in correspondence with each of the scheduled transmission time ranges. Network control program. In the transmission step process,
Transmitting a transmission packet to be transmitted first designated by a head address stored in the head packet address storage unit provided corresponding to the scheduled transmission time range including the current time, and then pairing with the transmission packet; By repeating the operation of transmitting the transmission packet specified by the head address stored in the storage means in the transmission packet as long as the head address stored in the packet storage means exists, the current packet The network control program according to claim 9, wherein all transmission packets to be transmitted are transmitted within the transmission scheduled time range including a time.

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