JP2017204801A - Packet transfer device and packet transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a burst traffic solution also taking account of power consumption with low delay.SOLUTION: A packet transfer device connected with a network and transmitting/receiving packets via a network has multiple interfaces, each accommodating an input line and an output line for transmitting/receiving packets via a network, and a packet relay section for determining the output destination of a packet received at the interface, where the interface includes a packet management section for managing transmission/reception packets, and the packet management section switches operational state according to the reception state of packet and the processing state of the packet relay section.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a packet transfer technique, and more particularly to a packet transfer method and a packet transfer apparatus in a network where burst traffic occurs.

In recent years, instantaneous burst traffic (microburst) from a server, burst traffic generated by multiple sessions of smart phone applications and simultaneous handovers accompanying mass movement of users during commuting hours have become a problem.
Another problem is that malicious traffic such as a distributed denial of service (DDoS) attack is generated maliciously to bring down the network.
Thus, there are two types of burst traffic: communication concentration due to increase in user traffic and communication concentration due to malicious attacks.
On the other hand, in the prior art, the former has been solved by delaying and smoothing the packet by traffic shaping as described in Patent Document 1. For the latter, as described in Patent Document 2, a certain amount of load is allowed, and a packet exceeding the standard is discarded.

JP 2001-326688 A JP 2004-254164 A

  Since both Patent Document 1 and Patent Document 2 described above start processing after receiving a packet, a delay occurs. Furthermore, in Patent Document 1, it is necessary to store all received packets in a memory, and a delay occurs even when burst traffic is not generated. Furthermore, since the process is performed after receiving the packet, there is a problem that the traffic to be processed remains large and the power consumption increases.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a burst traffic solution with low delay and considering power consumption.

  The present invention has been made to solve the above problems, and in a packet transfer apparatus that is connected to a network and transmits / receives a packet via the network, for example, each input for transmitting / receiving the packet via the network A plurality of interface units that accommodate lines and output lines; a packet relay unit that determines an output destination of a packet received in the interface unit; and a packet management unit that manages transmission and reception packets in the interface unit. The management unit switches the operation state according to the reception status of the packet and the processing status of the packet relay unit.

  In addition, the operation state includes a high load mode and a low load mode, and the packet management unit switches the operation state to the high load mode or the low load mode based on the high load notification notified from the packet relay unit. It is a thing.

  According to the present invention, it is possible to provide a burst traffic solution with low delay and considering power consumption.

It is a figure which shows the structure of the packet transfer apparatus in one Example of this invention. It is a figure which shows the structure of the packet management part of the packet transfer apparatus in one Example of this invention. It is a figure which shows the structure of the packet order control part of the packet management part of the packet transfer apparatus in one Example of this invention. It is a figure explaining one state of the several states of a packet management part. It is a figure explaining one state of the several states of a packet management part. It is a figure explaining one state of the several states of a packet management part. It is a figure explaining one state of the several states of a packet management part. It is a figure explaining one state of the several states of a packet management part. It is a figure explaining one state of the several states of a packet management part. It is a state transition diagram of the packet management part in one Example of this invention. It is a sequence diagram explaining operation | movement of the packet transfer apparatus in one Example of this invention. It is a sequence diagram explaining operation | movement of the packet transfer apparatus in one Example of this invention. It is a sequence diagram explaining operation | movement of the packet transfer apparatus in one Example of this invention. It is a flowchart which shows the packet transfer process in one Example of this invention. It is a flowchart which shows the packet transfer process in one Example of this invention. It is a block diagram of the packet receiving part in one Example of this invention.

  Hereinafter, examples will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a packet transfer apparatus in an embodiment of the present invention.
The packet transfer apparatus 100 shown in FIG. 1 includes a plurality of interface units 110 and a single packet relay unit 140. Each interface unit 110 includes a packet transmission unit 120, a packet reception unit 200, and a packet management unit 300. The packet transfer apparatus 100 receives a packet from the network via the input line 101. For the received packet, the packet relay unit 140 determines the output destination and transmits it to the network via the output line 102. The interface unit determines whether or not to store the packet in the memory 130 according to the load status of the packet relay unit 140. If the packet is stored in the memory 130, the load of the packet relay unit 140 decreases. The stored packet is read from the memory 130 and transferred to the packet relay unit 140. The details will be described with reference to FIG. 2 and subsequent figures. The dotted arrow in FIG. 1 indicates the packet transmission direction, and the solid arrow indicates the control signal transmission direction.

FIG. 2 is a diagram showing the configuration of the packet management unit of the packet transfer apparatus according to the embodiment of the present invention.
The packet management unit 300 includes a packet path setting unit 310, a memory controller unit 320, a packet suppression determination unit 330, and a packet order control unit 400. The packet route setting unit 310 transfers the received packet to either the memory controller unit 320 or the packet order control unit 400 in accordance with the route instruction 303 from the packet order control unit 400.
The memory controller unit 320 controls write and read access to the memory 130 and manages the memory 130. The memory controller unit 320 writes the packets transferred from the packet path setting unit 310 to the memory 130 in the order of arrival, and writes the packets stored in the memory 130 to the memory in accordance with the read request 305 from the packet sequence control unit 400. Like in the order of arrival. In addition, the memory controller unit 320 notifies the packet order control unit 400 of the usage status 302 of the memory 130. Here, as the usage status 302 of the memory 130, for example, the usage amount of the memory is notified.

When the high load notification 103 is notified from the packet relay unit 140, the packet suppression determination unit 330 determines that the packet relay unit 140 is in a high load state, and issues a transmission suppression instruction 301 to the packet order control unit 400. The packet suppression determination unit 330 has a timer, and cancels the transmission suppression instruction 301 for the packet order control unit 400 after a certain time has elapsed after the high load notification 103 disappears. Further, the packet suppression determination unit 330 generates a PAUSE frame in accordance with the reception suppression instruction 304 from the packet order control unit 400 and transmits it to the network via the output line 102.
The packet order control unit 400 performs a route instruction 303 for the packet route setting unit 310 and a reception suppression instruction 304 for the packet suppression determination unit based on the transmission suppression instruction 301 from the packet suppression determination unit 330 and the usage status 302 of the memory 130. The packet processing is performed by guaranteeing the packet order.

FIG. 3 is a diagram showing the configuration of the packet order control unit in one embodiment of the present invention.
The packet order control unit 400 includes a temporary accumulation buffer 410 and an order management unit 420. Temporary accumulation buffer 410 temporarily stores packets transferred from packet path setting unit 310.
The order management unit 420 includes a memory threshold determination unit 421 and a route determination unit 422. The memory threshold value determination unit 421 has a minimum threshold value and a maximum threshold value. The order management unit 420 determines the state of the memory 130 based on the memory usage status 302 received from the memory controller unit 320, the minimum threshold value of the memory threshold value determination unit 421, and the maximum threshold value, and notifies the path determination unit 422. The path determination unit 422 determines the state of the packet management unit 300 based on the state of the memory 130 received from the memory threshold determination unit 421 and the presence / absence of the transmission suppression instruction 301 from the packet relay unit 140.

FIG. 4 is a diagram illustrating a plurality of states of the packet management unit.
In FIG. 4A to FIG. 4F below, in order to make it easy to see the packet transmission / reception direction, only the dotted arrow indicating the packet transmission / reception direction is described, and the arrow indicating the control information transmission / reception direction is omitted.
FIG. 4A is a diagram illustrating a state 1 of the packet management unit.
The state 1 is Empty indicating that there is no transmission suppression instruction 301 from the packet suppression determination unit 330 to the packet order control unit 400 and the usage status 302 of the memory 130 is a state where the memory is not used. The unit 300 is receiving a packet via the packet receiving unit 200. The absence of the transmission inhibition instruction 301 indicates that the packet relay unit 140 has not been notified of a high load and the packet relay unit 140 has a low load and can transfer a packet to the packet relay unit 140. Further, since the usage status 302 of the memory 130 is Empty, the received packet is not transferred to the memory 130 via the memory controller 320, and the packet is relayed from the packet path setting unit 310 via the packet order control unit 400. To the unit 140.

FIG. 4B is a diagram illustrating a state 2 of the packet management unit.
In state 2, a high load notification is notified from the packet relay unit 140, and there is a transmission suppression instruction 301 from the packet suppression determination unit 330 to the packet order control unit 400. State 2 is a state in which the usage status 302 of the memory 130 is equal to or less than the maximum threshold value stored in the memory threshold value determination unit 421 in FIG. 3 and the packet management unit 300 is receiving a packet via the packet reception unit 200. is there. The presence of the transmission suppression instruction 301 indicates that a high load notification has been notified from the packet relay unit 140, the packet relay unit 140 has a high load, and packet transfer to the packet relay unit 140 is prohibited. Further, since the usage status 302 of the memory 130 is equal to or less than the maximum threshold value, the received packet is stored in the memory 130 from the packet path setting unit 310 via the memory controller unit 320.

FIG. 4C is a diagram illustrating a state 3 of the packet management unit.
State 3 is a state in which there is no transmission suppression instruction 301 from the packet suppression determination unit 330 to the packet order control unit 400, the usage status 302 of the memory 130 is other than Empty, and the packet management unit 300 has not received a packet. . The absence of the transmission inhibition instruction 301 indicates that the packet relay unit 140 has not been notified of a high load and the packet relay unit 140 has a low load and can transfer a packet to the packet relay unit 140. Further, since the usage status 302 of the memory 130 is not Empty, the packet sequence control unit 400 reads the packets stored in the memory 130 in the order of arrival and forwards them to the packet relay unit 140 via the packet sequence control unit 400. It is in a state.

FIG. 4D is a diagram illustrating a state 4 of the packet management unit.
In state 4, there is no transmission suppression instruction 301 from the packet suppression determination unit 330 to the packet order control unit 400, the usage status 302 of the memory 130 is equal to or less than the minimum threshold stored in the memory threshold determination unit 421 in FIG. The management unit 300 is receiving a packet. The absence of the transmission inhibition instruction 301 indicates that the packet relay unit 140 has not been notified of a high load and the packet relay unit 140 has a low load and can transfer a packet to the packet relay unit 140. In addition, since the usage status 302 of the memory 130 is equal to or less than the minimum threshold, while the packets are read from the memory 130 in the order of arrival, the received packets are stored in the temporary storage buffer 410 and the packets read from the memory 130 in the order of arrival are packetized. In this state, the data is transferred to the relay unit 140. The packets stored in the memory 130 are read in the order of arrival and transferred to the packet relay unit 140, and then the received packets stored in the temporary storage buffer 410 are transferred to the packet relay unit 140 to realize the order guarantee. .

FIG. 4E is a state diagram showing state 5 of the packet management unit.
In state 5, there is no transmission suppression instruction 301 from the packet suppression determination unit 330 to the packet order control unit 400, and the usage status 302 of the memory 130 indicates the minimum threshold value and the maximum threshold value stored in the memory threshold determination unit 421 in FIG. In this state, the packet management unit 300 is receiving a packet. The absence of the transmission inhibition instruction 301 indicates that the packet relay unit 140 has not been notified of a high load and the packet relay unit 140 has a low load and can transfer a packet to the packet relay unit 140. Further, since the usage status 302 of the memory 130 is between the minimum threshold value and the maximum threshold value, the received packets are stored in the memory 130 in the order of arrival, the packets are read from the memory 130 in the order of arrival, and transferred to the packet relay unit 140. It is in a state.

FIG. 4F is a state diagram showing state 6 of the packet management unit.
In state 6, a high load notification is notified from the packet relay unit 140, the transmission suppression instruction 301 is sent from the packet suppression determination unit 330 to the packet order control unit 400, and the usage status 302 of the memory 130 is the memory of FIG. 3. This is a state in which the packet management unit 300 is receiving a packet at or above the maximum threshold stored in the threshold determination unit 421. The presence of the transmission suppression instruction 301 indicates that a high load notification has been notified from the packet relay unit 140, the packet relay unit 140 has a high load, and packet transfer to the packet relay unit 140 is prohibited. Further, since the usage status 302 of the memory 130 is equal to or greater than the maximum threshold, the memory 130 is also in a state where the packet suppression determination unit 330 generates a PAUSE frame and transmits it to the packet transmission unit 120. The received packet is determined by the memory controller unit 320 as to whether it can be stored in the memory 130. If it cannot be stored, it is discarded.

FIG. 5 is a state transition diagram of states 1 to 6 shown in FIG.
A state in which no packet is stored in the memory 130 and a state in which the packet management unit 300 receives a packet at the packet path setting unit 310 is “state 1” in FIG. Here, when the packet relay unit 140 changes from a low load to a high load, the state transits to “state 2”.
“State 2” is a state in which a packet is stored in the memory 130. When the packet relay unit 140 is changed from a high load to a low load, the packet can be transferred to the packet relay unit 140 and stored in the memory 130. Transition to "state 3" by reading a packet. When the packet path setting unit 310 receives a packet when transitioning to “state 3”, the state transitions to “state 5”. On the other hand, when “state 2” continues for a certain period of time, the packet is stored in the memory 130 up to the maximum threshold, and the packet suppression determination unit 330 generates a PAUSE frame, thereby transitioning to “state 6”.
In “state 3”, when the packet relay unit 140 is changed from a low load to a high load, packet transfer to the packet relay unit 140 is prohibited, and when the received packet is stored in the memory 130, the state transits to “state 2”. Further, when “state 3” continues for a certain period of time, the memory 130 becomes empty and transitions to “state 1”.

Next, when the packet is received by the packet path setting unit 310 in a state where the packet exceeding the minimum threshold is stored in the memory 130, the state transits to “state 5”. Further, when a packet smaller than the minimum threshold is stored in the memory 130 and a packet is received by the packet path setting unit 310, the state transits to “state 4”.
“State 4” is a timing at which the packet transferred from the packet path setting unit 310 is stored in the temporary storage buffer 410, reads all the packets stored in the memory 130 in the order of arrival, and transfers them to the packet relay unit 140. Thereafter, the packet stored in the temporary storage buffer 410 is transferred to the packet relay unit, and transition is made to “state 1”.
In “state 5”, when the packet relay unit 140 is changed from a low load to a high load, packet transfer to the packet relay unit 140 is prohibited, and the received packet is stored in the memory 130, and the state transits to “state 2”. Further, when there is no packet transferred from the packet path setting unit 310, the state transits to “state 3”.
“State 6” is a state in which a packet is stored in the memory 130. When the packet relay unit 140 changes from a high load to a low load, the packet can be transferred to the packet relay unit 140 and stored in the memory 130. Transition to "state 3" by reading a packet. When the packet path setting unit 310 receives a packet when transitioning to “state 3”, the state transitions to “state 5”.
In FIG. 5, “state 1” and “state 4” in which the packet received from the packet receiver 200 is transferred to the packet relay unit 140 without being stored in the memory 130 are received in the low load mode and received from the packet receiver 200. The “state 2”, “state 3”, “state 5”, and “state 6” in which the packet stored in the memory 130 or the packet stored in the memory 130 is read are operations in the high load mode.

6 to 8 are sequence diagrams for explaining transmission / reception of packets and control signals in the packet transfer apparatus and state transition of the packet management unit.
6 to 8, a dotted line indicates that no signal is transmitted.
In FIG. 6, description will be given of packet order guarantee in the transition from “state 1” to “state 2”.
In the “state 1” state, the packet reception unit receives a plurality of packets S10, and transfers the received packets S10 to the packet relay unit, thereby increasing the load on the packet relay unit. The packet relay unit transmits a high load notification S602 to the packet suppression determination unit. In response to this, the packet suppression determination unit transmits a transmission suppression instruction S603 to the packet order control unit, and the packet order control unit transmits a received packet to the memory controller unit to the packet path setting unit. I do. Next, the packet path unit stores the received packets in the memory 130 via the memory controller in the order of arrival. Thereafter, memory read S32 is performed twice from the memory 130 in the order of arrival after a fixed time after the high load notification is resolved. The usage state S608 of the memory 130 becomes Empty, and the state returns to “state 1”.

Next, referring to FIG. 7, description will be given of packet order guarantee in the transition from “state 3” to “state 3”.
When the packet order control unit performs the memory read S33 once in the “state 3” state, the use state S703 of the memory 130 becomes equal to or less than the minimum threshold value. The packet order control unit instructs the packet route setting unit to send the received packet to the packet order control unit. Next, the memory read S34 is performed from the memory 130 in the order of arrival. The packet S704 received during the memory read S34 is stored in the temporary storage buffer 410. After the packet read from the memory read S35 is transferred to the packet relay unit 140, the packet is extracted from the temporary storage buffer 410 and transferred to S36 and the packet relay unit 140. The usage state S705 of the memory 130 becomes Empty, and the state returns to “state 1”.

FIG. 8 illustrates PAUSE frame transmission starting from “state 2” and transitioning from “state 2” to “state 6”.
When S37 receives a plurality of packets in the “state 2” state, the usage status S805 of the memory 130 becomes equal to or greater than the maximum threshold, and a reception suppression instruction S806 is issued to the packet suppression determination unit 330. Receiving the reception suppression instruction S806, the packet suppression determination unit 330 generates a PAUSE frame and transmits it to the network via the output line 102, thereby suppressing packet reception from the input line 101. Since there is no packet reception from the input line 101 for a certain period of time, the packet relay unit 140 has a low load. By performing memory read S38 from the memory 130 in the order of arrival, the generation of the PAUSE frame is stopped and the state 3 is entered. .

FIG. 9 is a flowchart showing packet transfer processing in one embodiment of the present invention.
FIG. 9 is a flowchart showing the operation of the packet management unit 300. The operation based on the flowchart is as follows.
Step S1: The packet route setting unit 310 receives the packet.
Step S2: The packet order control unit 400 checks whether there is a transmission suppression instruction 301 from the packet suppression determination unit 330. If YES, the process moves to step S3. If NO, the process moves to step S10.
Step S <b> 3: The packet order control unit 400 checks whether a packet is stored in the memory 130 according to the usage status of the memory 130 from the memory controller unit 320. If YES, the process moves to step S4. If NO, the process moves to step S6.
Step S4: The packet received by the packet path setting unit 310 is transferred to the packet order control unit 400.
Step S5: The absence of the transmission inhibition instruction 301 means that the packet relay unit 140 is in a low load state. Further, the fact that no packet is stored in the memory 130 means that there is no order relationship with the packet stored in the memory 130, so that the received packet is not transmitted from the packet path setting unit 310 via the memory to the packet relay unit 140. To complete the process.

Step S6: The packet order control unit 400 checks whether the usage amount of the memory 130 is equal to or smaller than the minimum threshold based on the usage status of the memory 130 from the memory controller unit 320. If YES, the process moves to step S7. If NO, the process moves to step S9.
Step S7: The packet received by the packet path setting unit 310 is transferred to the packet order control unit 400.
Step S8: The absence of the transmission inhibition instruction 301 means that the packet relay unit 140 is in a low load state. The fact that the packet is stored in the memory 130 has an order relationship with the packet stored in the memory 130, so the packet received by the packet order control unit 400 is stored in the temporary storage buffer 410, and the memory 130 Are read and transferred to the packet relay unit 140. Thereafter, the packet stored in the temporary storage buffer 410 is transferred to the packet relay unit 140 to guarantee the order of the packets, and the process is terminated.

Step S9: Move to step S11.
Step S11: The packet received by the packet path setting unit 310 is written to the memory 130 via the memory controller unit 320.
Step S12: The absence of the transmission inhibition instruction 301 means that the packet relay unit 140 is in a low load state. Further, if the memory usage of the memory 130 is equal to or greater than the minimum threshold value, an order relationship with the packets stored in the memory 130 occurs, so the packets stored in the memory 130 are read in the order of arrival, and the packet relay unit By transferring to 140, the order of the packets is guaranteed, and the process ends.

Step S10: Move to step S13.
Step S13: The packet order control unit 400 checks whether the usage amount of the memory 130 is equal to or larger than the maximum threshold value based on the usage status of the memory 130 from the memory controller unit 320. If NO, the process moves to step S14. If YES, the process moves to step S15.
Step S14: The presence of the transmission suppression instruction 301 means that the packet relay unit 140 is in a high load state, and therefore the packet order control unit 400 does not make a read request 305 to the memory controller unit 320. Further, if the memory usage of the memory 130 is equal to or less than the maximum threshold value, it is possible to store the packet in the memory 130. Therefore, the packet route setting in response to the route instruction 303 from the packet order control unit 400 to the memory 130 Unit 310 transfers the packet to memory controller unit 320. The memory controller unit 320 stores the packet in the memory 130 and ends the process.

Step S15: The packet order control unit 400 notifies the packet suppression determination unit 330 of the reception suppression instruction 304, and the process proceeds to step S16.
Step S16: The presence of the transmission suppression instruction 301 means that the packet relay unit 140 is in a high load state, and therefore the packet order control unit 400 does not make a read request 305 to the memory controller unit 320. Further, if the memory usage of the memory 130 is equal to or greater than the maximum threshold, it is impossible to store the packet in the memory 130, so the packet suppression determination unit 330 generates a PAUSE frame and transfers it to the packet transmission unit 120. Then, the data is transmitted to the network via the output line 102, and the process is terminated.

FIG. 10 is a block diagram of the packet receiver 200 in one embodiment of the present invention. The packet receiving unit 200 includes a PMA (Physical Media Attachment) 210, a PCS (Physical Coding Sublayer) 220, and a frame determination unit 230. The frame determination unit 230 performs packet management at L2. The frame determination unit 230 is provided in the packet reception unit 200, and is configured by the PMA 210, the PCS 220, and the frame determination unit 230. By performing packet management at L2 in the frame determination unit 230, the packet is discarded before the packet management unit 300. It is possible to prevent congestion of the network and to cope with security by discarding malicious packets and the like near the entrance L1 of the apparatus.
According to the embodiment of the present invention described above, it is possible to provide a burst traffic solution with low delay corresponding to the traffic volume without changing the order of traffic. Further, by managing packet management at a location close to L1, it is possible to suppress congestion of the network and power consumption associated therewith.

DESCRIPTION OF SYMBOLS 10 Packet 100 Packet transfer apparatus 101 Input line 102 Output line 103 High load notification 110 Interface part 120 Packet transmission part 130 Memory 140 Packet relay part 200 Packet reception part 210 PMA (Physical Media Attachment)
220 PCS (Physical Coding Sublayer)
230 Frame determination unit 300 Packet management unit 301 Transmission suppression instruction 302 Memory 130 usage status 303 Path instruction 304 Reception suppression instruction 305 Read request 310 Packet path setting unit 320 Memory controller 330 Packet suppression determination unit 400 Packet sequence control unit 410 Temporary storage buffer 420 Order Management Unit 421 Memory Threshold Determination Unit 422 Path Determination Unit

Claims (10)

A packet transfer device connected to a network and transmitting / receiving packets via the network,
A plurality of interface units each accommodating an input line and an output line for transmitting and receiving packets via the network, and a packet relay unit for determining an output destination of a packet received in the interface unit,
A packet transfer unit comprising a packet management unit for managing transmission / reception packets in the interface unit, wherein the packet management unit switches an operation state in accordance with a packet reception status and a processing status of the packet relay unit. apparatus. The packet transfer apparatus according to claim 1,
The operating state includes a high load mode and a low load mode,
The packet transfer unit, wherein the packet management unit switches the operation state to a high load mode or a low load mode based on a load state of the packet relay unit. The packet transfer apparatus according to claim 2, wherein
The packet management unit includes a memory for storing a packet received via the interface unit, and the packet management unit receives a packet received in the high load mode and the low load mode based on a usage state of the memory. A packet transfer apparatus for switching a transmission destination route to be stored in a memory or transferred to the packet relay unit. The packet transfer apparatus according to claim 3, wherein
The packet management unit is in a state in which the packet received by the transmission destination path is transferred to the packet relay unit, and when reading the packet stored in the memory, after the completion of reading from the memory A packet relay device characterized by taking an operation state of transferring the received packet to the packet relay device. The packet transfer apparatus according to claim 3, wherein
When a high load notification is notified from the packet relay unit, and the memory usage is equal to or greater than a preset threshold, the packet management unit sends the packet transfer device to the packet transfer device via the interface unit and the output line. A packet transfer apparatus for transmitting a signal for notifying the network side of transmission suppression of the packet. A packet transfer method in a packet transfer apparatus for transmitting and receiving packets via a network,
In the packet reception process before determining the output destination of the received packet, the operation state is switched according to the packet reception status in the packet transfer apparatus and the packet relay processing status for determining the packet output destination. A packet transfer method characterized by the above. The packet transfer method according to claim 6, comprising:
The operating state includes a high load mode and a low load mode,
A packet transfer method characterized by switching an operation state to a high load mode or a low load mode based on a load state of the packet relay processing. The packet transfer method according to claim 7, comprising:
Including a case of performing processing for storing a packet received via a network in a memory and a case of performing packet relay processing on a received packet without performing processing for storing in the memory,
In the high load mode and the low load mode, a process is performed to store the received packet in the memory based on the use state of the memory, or a packet is received with respect to the received packet without performing the process of storing in the memory. A packet transfer method characterized by selecting one of relay processing. The packet transfer method according to claim 8, comprising:
In a state in which packet relay processing is performed on a packet received without performing processing to be stored in the memory, reading of the packet stored in the memory is not completed by performing processing to store the received packet in the memory In this case, the packet relay apparatus performs packet relay processing on the received packet after completion of reading from the memory. The packet transfer method according to claim 8, comprising:
When the packet relay processing is in a high load state and the memory usage state is equal to or higher than a preset threshold value, a signal notifying the network side of packet transmission suppression to the packet transfer device is transmitted. A characteristic packet transfer method.

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