JP5187129B2 - Packet monitoring system, method and program thereof - Google Patents

Description

  The present invention relates to a packet monitoring method via a packet network. More specifically, the present invention specifies in which relay device these packets are lost when packets transmitted and received between the transmission device and the reception device in a packet network straddle a plurality of relay devices. The present invention relates to a packet monitoring system, a method thereof, and a program thereof.

  Telecommunications carriers are building high-speed data communication networks to realize higher value-added services. Since a high-speed data communication network requires a large traffic capacity, communication carriers are interested in low-cost and high-efficiency Ethernet (registered trademark) rather than high-cost SONET (Synchronous Optical Network).

  However, Ethernet (registered trademark), which was originally born as a LAN technology, had a function that telecommunications carriers lacked for use in a wide area network. It is a maintenance / management function of Ethernet (registered trademark), such as fault management and performance measurement. Therefore, ITU-T (International Telecommunication Union Telecommunication Standardization Sector) defines Y.1731 (see Non-Patent Document 1) as an OAM (Operations, Administration, Maintenance) standard technology that can be maintained and managed in the Ethernet (registered trademark) layer. doing.

  Non-Patent Document 1 defines not only fault management but also a performance measurement function. The performance measurement includes packet loss measurement, delay / delay fluctuation measurement, throughput measurement, etc., but this specification specializes in the packet loss measurement method.

  In the packet loss measurement method in Non-Patent Document 1, as described in Section 8.1.1 of Non-Patent Document 1, the transmitting apparatus transmits count information of user data packets transmitted while transmitting user data packets to the receiving apparatus. The reception device measures the number of packet losses by calculating the difference between the number of received user data packets and the count information transmitted from the transmission device.

  According to the packet loss measurement method in Non-Patent Document 1, it is possible to measure the number of packet losses for each micro flow. Furthermore, it is possible to measure the number of packet losses by regarding an aggregate of a plurality of microflows as a single microflow.

Further, Patent Documents 1 to 5 disclose techniques for complementing a lost packet by generating and transmitting / receiving a redundant packet.
JP 2003-229908 A JP 2004-274703 A JP 2004-289431 A JP 2006-217530 A JP 2008-131153 A ITU-T Recommendation Y.1731, "OAM functions and mechanics for Ethernet based networks".

  According to the packet loss measuring method in Non-Patent Document 1, the conventional packet loss measuring method is to measure the number of packet losses in units of microflows or aggregation microflows (aggregation microflows). Is possible.

  However, when an aggregation microflow packet loss occurs, it is unknown which microflow packet the lost packet contains. Of course, the problem can be solved by monitoring the packet loss not only in the aggregation microflow but also in the microflow. However, in a relay apparatus that accommodates a large number of microflows, monitoring the packet loss for each microflow requires a huge amount of memory, which is problematic in terms of both cost and labor.

  In addition, the inventions disclosed in Patent Documents 1 to 5 described above supplement a lost packet with a redundant packet, but it is difficult to specify where the packet is lost. There is a point.

The present invention has been made in view of the above, and when measuring packet loss for an aggregation microflow, it is possible to determine which microflow packet a lost packet belongs to without monitoring the packet loss for each microflow. It is to provide a packet monitoring system, a method thereof, and a program thereof that can be specified.

In order to solve the above-described problem, a packet monitoring system according to the present invention aggregates communication paths connecting a transmission-side terminal and a reception-side terminal by a first relay device, and the aggregated communication route is a second relay device. A packet monitoring system in a network connected to the receiving side terminal from the second relay device, comprising a network management system for monitoring a packet loss in the second relay device, The relay device performs forward error correction coding between the headers of a plurality of packets related to communication between the transmitting terminal and the receiving terminal, converts the result of the code operation into redundant packets, and combines the plurality of packets together with the plurality of packets. The redundant packet is transmitted to the second relay device, and the second relay device transmits the plurality of packets to the receiving-side terminal and is received from the first relay device. And forward error correction decoding to and from the plurality of packets, and notifies the calculation result of the correction decoding to the network management system.

In order to solve the above-described problem, a packet monitoring method according to the present invention aggregates communication paths connecting a transmission-side terminal and a reception-side terminal by a first relay device, and the aggregated communication route is a second relay device. A packet monitoring method for monitoring a packet loss in a network connected to the receiving side terminal from the second relay device by a network management system, wherein the first relay device and the transmitting side terminal A first error correction code is generated between headers of a plurality of packets related to communication with a receiving terminal, and the result of the code operation is converted into a redundant packet and transmitted to the second relay device together with the plurality of packets. And the second relay device transmits the plurality of packets to the receiving terminal and receives the redundant packet and the plurality of packets received from the first relay device. Forward error correction and decoding between, characterized in that it comprises a second step of notifying the operation result of the correction decoding to the network management system, the.

In order to solve the above-described problem, a packet monitoring program according to the present invention aggregates communication paths connecting a transmission-side terminal and a reception-side terminal with a first relay device, and the aggregated communication route is a second relay device. A packet monitoring program for monitoring a packet loss in a network connected to the receiving side terminal from the second relay device by a network management system, which relates to communication between the transmitting side terminal and the receiving side terminal The first relay performs a first error correction code between headers of a plurality of packets, converts the result of the code operation into a redundant packet, and transmits the redundant packet together with the plurality of packets to the second relay device. And the redundant packet and the plurality of packets received from the first relay device. Forward error correction and decoding between, characterized in that to execute a second process of notifying the operation result of the correction decoding to the network management system to the second relay device.

  As described above, according to the present invention, the first relay device performs forward error correction code between the headers of a plurality of packets related to communication between the first terminal and the second terminal, and performs the code calculation. The second relay device performs forward error correction decoding between the redundant packet received from the first relay device and a plurality of packets, and notifies the network management system of the operation result of the correction decoding. By performing packet loss measurement for an aggregation microflow, a packet monitoring system that can specify which microflow packet a lost packet belongs to without monitoring packet loss for each microflow, The method and the program can be provided.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
A first embodiment according to the present invention will be described in detail with reference to the drawings.
<Configuration of First Embodiment>
FIG. 1 is a configuration diagram of a packet loss monitoring system according to the present embodiment. As shown in FIG. 1, the packet loss monitoring system according to the present embodiment includes terminals 11 and 21 that are transmission side terminals, terminals 12 and 22 that are reception side terminals, and a first relay device that exists on the transmission side. A relay device 31, a relay device 33 that is a second relay device on the receiving side, and a relay device 33 that is a third relay device that relays between the relay device 31 and the relay device 33.

  The packet sequence that flows between the terminals 11 and 12 constitutes a microflow 1 that is a communication path, and the packet sequence that flows between the terminals 21 and 22 constitutes a microflow 2 that is a communication path. Further, the relay apparatuses 31, 32, and 33 aggregate the microflows 1 and 2, and transfer the packets through the aggregation microflow 3 that is the aggregated communication path.

  There are various ways to aggregate microflows as aggregation microflows. There is a method of transferring micros in a simple grouping method, and an interworking method of transferring microflow packets by encapsulating them in an aggregation microflow header. Hereinafter, in order to simplify the description in the present embodiment, the description will be made on the assumption that the relay apparatus encapsulates and transfers micropackets. However, it is not always necessary to encapsulate a micropacket in a practical relay device.

  FIG. 2 shows a format of a packet flowing through the microflows 1 and 2. The first header (1) in the packet 101 indicates the microflow 1, and the first header (2) in the packet 201 indicates the microflow 2.

  FIG. 3 is a configuration diagram of the relay device 31 existing on the transmission side in the present embodiment. The relay device 31 illustrated in FIG. 3 includes a packet reception unit 311, a memory 312, an FEC code calculation unit 313, an encapsulation unit 314, and a packet transmission unit 315.

  The packet receiving unit 311 stores the packet transmitted from the terminal 11 or 21 in the memory 312 and then transmits the packet to the encapsulation unit 314.

  The memory 312 stores a packet received from the packet receiving unit 311.

  If the number of packets stored in the memory 312 satisfies the FEC code calculation request condition, the FEC code calculation unit 313 performs FEC code calculation between a plurality of packets, and transmits the FEC code calculation result to the encapsulation unit 314.

  In this FEC code calculation, the code calculation results of the number of packets satisfying the FEC code calculation requirement described above are converted into redundant packets.

  The algorithm used in the FEC code calculation is not particularly limited, and can be applied as necessary, such as a parity code or a cyclic code. However, when code calculation is performed on a variable-length packet, it is necessary to unify the packet size. In this embodiment, the following two methods are used.

  In the method 1, as shown in FIG. 7, a small-size packet is filled with “NULL” information in accordance with the MAX value of the packet size, and a sign operation is performed in accordance with the MAX value of the packet size.

  In the method 2, as shown in FIG. 8, only a fixed size (for example, 64 bytes) for a part of the packet is subjected to a sign operation. Since the latter has a smaller redundant packet size than the former, higher transfer efficiency can be achieved.

  In the FEC code calculation performed by the relay device 31 or the like, as shown in FIGS. 7 and 8, a part or all of the information bytes of the packet including the first header related to the network protocol are excluded except for the second header. An FEC operation interval is assumed, and this FEC operation interval is regarded as a header to be subjected to FEC code calculation.

  The encapsulation unit 314 adds a second header to the packets and redundant packets transmitted from the packet reception unit 311 and the FEC code calculation unit 313. The second header includes an FEC header and an aggregation header related to packet encapsulation. The FEC header is added as necessary. The FEC header includes identification information for distinguishing between user data and redundant data, and information related to a code operation such as a packet sequence number.

  Here, FIG. 6 is a diagram illustrating a format of an aggregation packet that flows through the aggregation microflow according to the present embodiment. The packets 301 and 302 shown in FIG. 6 are obtained by adding a second header to the packets 101 and 102, respectively.

  The packet transmission unit 315 transmits the packet transmitted from the encapsulation unit 314 to the relay device 32 or 33.

  FIG. 4 is a configuration diagram of the relay device 32 existing on the relay side according to the present embodiment. The relay device 32 illustrated in FIG. 4 includes a packet reception unit 321, a memory 322, an FEC decoding calculation unit 323, a packet loss monitoring unit 324, and a packet transmission unit 325.

  The packet reception unit 321 receives the aggregation packet transmitted from the relay device 31, stores the received aggregation packet in the memory 322, and transmits the aggregation packet to the packet transmission unit 325.

  The memory 322 stores the packet received from the packet receiving unit 321.

  When the number of packets stored in the memory 322 satisfies the FEC decoding calculation request condition or when the packet receiving unit 321 receives a packet of the next block, the FEC decoding calculation unit 323 performs FEC decoding calculation between a plurality of packets. The FEC decoding calculation result is transmitted to the packet loss monitoring unit 324.

  In this FEC decoding calculation, the packet loss in the plurality of packets is detected by checking the sign of the plurality of packets and the redundant packets corresponding to these packets.

  The FEC decoding calculation algorithm uses a decoding calculation algorithm corresponding to the FEC code calculation algorithm used in the relay device 31. Further, the same method as the relay apparatus 31 is adopted for FEC encoding / decoding for variable length packets.

  The packet loss monitoring unit 324 notifies the NMS (Network Management System) of the decoding calculation result unless the calculation result from the FEC decoding calculation unit 323 is “All 0”, that is, there is no packet loss. To do.

  The packet transmission unit 325 transmits the packet transmitted from the packet reception unit 321 to the relay device 32 or 33.

  FIG. 5 is a configuration diagram of the relay device 33 existing on the receiving side in the present embodiment. The relay apparatus 33 illustrated in FIG. 5 includes a packet reception unit 331, a decapsulation unit 332, a memory 333, an FEC decoding calculation unit 334, a packet loss monitoring unit 335, and a packet transmission unit 336.

  The packet reception unit 331 transmits the packet transmitted from the relay device 31 or 32 to the decapsulation unit 332.

  The decapsulation unit 332 receives the packet transmitted from the packet reception unit 331, reads the second header of the received packet, decapsulates it, and stores it in the memory 333.

  Also, the decapsulation unit 332 decapsulates only the plurality of packets described above, that is, the user data packet as shown in FIG. 8 among the received packets, and transmits the decapsulation to the packet transmission unit 336. At this time, the redundant packet is not sent to the packet transmission unit 336 but discarded.

  The memory 333 stores a packet received from the decapsulation unit 332.

  When the number of packets stored in the memory 333 satisfies the FEC decoding calculation request condition or when the decapsulation unit 332 receives a packet of the next block, the FEC decoding calculation unit 334 performs FEC decoding calculation between the packets, The decoding calculation result is transmitted to the packet loss monitoring unit 335. The FEC decoding calculation algorithm uses a decoding calculation algorithm corresponding to the FEC code calculation algorithm used in the relay device 31. Further, the same method as the relay apparatus 31 is adopted for FEC encoding / decoding for variable length packets.

  If the calculation result from the FEC decoding calculation unit 334 is not “All 0”, the packet loss monitoring unit 335 notifies the NMS of the decoding calculation result.

The packet transmission unit 336 transmits only the user data packet transmitted from the decapsulation unit 332 to the terminals 12 and 22.
<Operation of First Embodiment>
As illustrated in FIG. 1, the terminal 11 transmits a packet to the terminal 12, and the terminal 21 transmits a packet to the terminal 22. The former packet flow is referred to as microflow 1, and the latter packet flow is referred to as microflow 2.

  Here, the relay devices 31, 32, and 33 check only the aggregation header of the packets encapsulated with the aggregation header added to the microflow packets transmitted and received between the terminals 11, 12, 13, and 14. However, the conventional packet loss measurement method has a problem that even if the packet loss can be detected by the aggregation microflow, it cannot be specified to which microflow the packet belongs.

  In the present embodiment, the following operation is performed in order to solve such a problem.

  When the relay device 31 receives the microflow 1 or microflow 2 packet, the relay device 31 performs an FEC code operation between the packets, encapsulates the received packet and the FEC operation result (redundant packet) in the second protocol header, and sends it to the relay device 32. Send.

  The relay device 32 copies a plurality of packets corresponding to a single redundant packet to the packet transmitted from the relay device 31, stores them in the memory 322, and transmits these packets to the next relay device 33. To do. For the packet copied to the memory 322, the FEC decoding operation described above is performed between the packets, and a lost packet is generated or bit information of a part of the packet is reproduced and notified to the NMS.

  The NMS can specify which microflow packet the lost packet is based on the information of the lost packet transmitted from the relay device 32.

  The relay device 33 copies a plurality of packets corresponding to a single redundant data to the packet transmitted from the relay device 32 and stores it in the memory 333, and then decapsulates user data packets other than the redundant packet. Transmit to terminals 12 and 22. For the packet copied to the memory 333, after decapsulating these second headers, the FEC decoding operation described above is performed between the packets to generate a lost packet or a bit information of a part of the lost packet. Play and notify NMS.

  The NMS can identify which microflow packet the lost packet is based on the information of the lost packet transmitted from the relay device 33.

  In the present embodiment, in the relay device that transfers the microflow by encapsulation by aggregation, the FEC calculation is performed between the aggregation packets to reproduce the header information of the microflow, so that the header of the microflow is not terminated. Even if the microflow of the lost packet is specified and the packet loss monitoring means is not provided for each microflow, the packet loss status of the microflow can be monitored.

In this embodiment, the transmission side relay device, the reception side relay device, and the relay device that relays these relay devices are combined with the terminal. However, the transmission side relay device and the reception side relay are connected to the terminal. Even when combined with a device, it is possible to monitor the packet loss status of the microflow.
[Second Embodiment]
A second embodiment according to the present invention will be described in detail with reference to the drawings.
<Configuration of Second Embodiment>
FIG. 9 is a configuration diagram of a relay apparatus existing on the relay side in the present embodiment. Referring to FIG. 9, the present embodiment is different in that the relay device 32 in the first embodiment shown in FIG. 4 includes an FEC code calculation unit 346.

As shown in FIG. 9, the FEC code calculation unit 346 extracts only user data packets other than redundant packets from the packets stored in the memory 342, performs FEC code calculation between the packets, and outputs the FEC code calculation result. Is transmitted to the packet transmission unit 345.
<Operation of Second Embodiment>
Since the relay device 32 in the first embodiment transmits the received packet sequence to the relay device 33 as it is, the packet lost between the relay devices 31 and 32 is not only the relay device 32 but also the relay device 33. Detected.

  Since both the relay devices 32 and 33 finally transmit the packet loss detection result to the NMS, if the NMS grasps the positional relationship of the terminals in the entire network, the position where the packet loss has occurred may be specified. Although it is possible, it is difficult for the relay apparatuses 32 and 33 to directly specify the position of the packet loss.

  In the present embodiment, the following operations are performed in order for the relay apparatuses 32 and 33 to directly specify the position where the packet loss has occurred.

  The relay device 32 in the present embodiment may temporarily buffer the received redundant packet and a plurality of packets corresponding to the received redundant packet to restore the lost packet. However, when these multiple packets are buffered, delay fluctuation between the packets increases.

  The relay device 32 in the present embodiment copies the received redundant packet and a plurality of packets corresponding to the received redundant packet to minimize delay fluctuation between the packets, and then in these packets, Only user data packets other than redundant data packets are transferred to the next relay device 33.

  Thereafter, the FEC code calculation is performed only on the user data packet among the packets held in the memory 342, and the result of the FEC code calculation is transmitted to the relay apparatus 33 continuously after the user data packet. .

  Further, the relay device 32 in the present embodiment uses the packet stored in the memory 342 in the same manner as the relay device 32 in the first embodiment in order to specify the header information of the lost packet. FEC decoding operation is performed between them, and the header of the lost packet related to microflows 1 and 2 is specified.

  In the present embodiment, in a relay device that encapsulates and transfers a microflow packet with an aggregation header, the microflow header is not terminated by performing an FEC operation between the aggregation packets and reproducing the microflow header information. However, it is possible to identify the microflow of the lost packet and monitor the packet loss status of the microflow without providing a packet loss monitoring unit for each microflow.

  The packet loss monitoring system, method, and program according to the present invention can be used in the technical field of encapsulating and transmitting packets such as VPN (Virtual Private Network).

It is a block diagram of the packet loss monitoring system which concerns on the 1st Embodiment of this invention. It is a figure which shows the format of the packet which flows through the microflow which concerns on the 1st Embodiment of this invention. It is a block diagram of the relay apparatus which exists in the transmission side in the 1st Embodiment of this invention. It is a block diagram of the relay apparatus which exists in the relay side in the 1st Embodiment of this invention. It is a block diagram of the relay apparatus which exists in the receiving side in the 1st Embodiment of this invention. It is a figure which shows the format of the aggregation packet which flows through the aggregation microflow which concerns on the 1st Embodiment of this invention. In the aggregation packet according to the first embodiment of the present invention, a small-sized packet is filled with “NULL” information in accordance with the MAX value of the packet size. In the aggregation packet which concerns on the 1st Embodiment of this invention, it is the figure which showed carrying out code | symbol calculation only for predetermined fixed size from the head of a 1st header. It is a block diagram of the relay apparatus which exists in the relay side in the 2nd Embodiment of this invention.

Explanation of symbols

1, 2 Flow 3 Aggregation flow 11, 12, 21, 22 Terminal 31, 32, 33 Relay device 101, 201, 301, 302 Packet 311 Packet receiving unit 312 Memory 313 FEC code calculation unit 314 Encapsulating unit 315 Packet transmitting unit 321 Packet reception unit 322 Memory 323 FEC decoding operation unit 324 Packet loss monitoring unit 325 Packet transmission unit 331 Packet reception unit 332 Decapsulation unit 333 Memory 334 FEC decoding operation unit 335 Packet loss monitoring unit 336 Packet transmission unit 341 Packet reception unit 342 Memory 343 FEC decoding operation unit 344 Packet loss monitoring unit 345 Packet transmission unit 346 FEC code operation unit

Claims (27)

The communication path connecting the transmission side terminal and the reception side terminal is aggregated by the first relay apparatus, the aggregated communication path is connected to the second relay apparatus, and the second relay apparatus is connected to the reception side terminal A packet monitoring system in the network
A network management system for monitoring packet loss in the second relay device;
The first relay device performs forward error correction coding between headers of a plurality of packets related to communication between the transmission side terminal and the reception side terminal, converts the result of the code calculation into redundant packets, and Sent to the second relay device together with the packet,
The second relay device transmits the plurality of packets to the receiving terminal and forward error correction decodes between the redundant packet and the plurality of packets received from the first relay device; A packet monitoring system for notifying the network management system of a calculation result of correction decoding. A third relay device that relays between the first relay device and the second relay device;
The third relay device transmits the redundant packet and the plurality of packets received from the first relay device to the second relay device, and forwards between the redundant packet and the plurality of packets. The packet monitoring system according to claim 1, wherein error correction decoding is performed, and a calculation result of the correction decoding is notified to the network management system.   The third relay device performs forward error correction coding between the headers of the plurality of packets received from the first relay device, converts the result of the code operation into a redundant packet, and combines the plurality of packets with the first packet. The packet monitoring system according to claim 2, wherein the packet is transmitted to the second relay device. The first relay device is
A packet receiver that receives the plurality of packets from the transmitting terminal;
A memory for storing the received plurality of packets;
A forward error correction code between the headers of the plurality of packets stored in the memory, and an FEC code operation unit that converts the result of the code operation into a redundant packet;
Receiving the plurality of packets from the packet receiving unit and the redundant packet from the FEC code calculation unit, respectively, and adding a second header having information on the code calculation to each of the plurality of packets and the redundant packet An encapsulation unit to
A packet transmission unit that transmits a packet transmitted from the encapsulation unit to the second relay device or the third relay device;
The packet monitoring system according to any one of claims 1 to 3, further comprising: The second relay device is
A packet receiver that receives the plurality of packets and the redundant packet from the first relay device or the third relay device;
A decapsulator for reading a second header of the plurality of packets;
A memory for storing the plurality of packets and the redundant packet received by the packet receiver;
An FEC decoding arithmetic unit that performs forward error correction decoding between the redundant packet and the plurality of packets stored in the memory;
A packet loss monitoring unit for notifying the network management system of the calculation result of the correction decoding;
A packet transmission unit that receives a packet from the decapsulation unit and transmits the received packet to the reception-side terminal;
With
The packet monitoring system according to claim 4, wherein the decapsulation unit transmits only the plurality of packets to the packet transmission unit. The third relay device is
A packet receiver that receives the plurality of packets and the redundant packet from the first relay device;
A memory for storing the plurality of packets and the redundant packet received by the packet receiver;
An FEC decoding arithmetic unit that performs forward error correction decoding between the redundant packet and the plurality of packets stored in the memory;
A packet loss monitoring unit for notifying the network management system of the calculation result of the correction decoding;
A packet transmitter that receives the plurality of packets and the redundant packet from the packet receiver, and transmits the received packet to the receiving terminal;
The packet monitoring system according to claim 5, further comprising: The third relay device further includes a FEC code calculation unit that performs forward error correction code between the headers of the plurality of packets, and converts the result of the code calculation into a redundant packet.
The packet monitoring system according to claim 6, wherein the packet transmission unit transmits the redundant packet to the second relay device. The first relay device or the third relay device is
8. The forward error correction code according to claim 1, wherein the header is a part or all of information bytes of a predetermined packet including a header related to a network protocol in the plurality of packets. The packet monitoring system according to any one of claims. The first relay device or the third relay device is
When forward error correction coding is performed on all information bytes of the variable length packet including the header, if the variable length packet is equal to or smaller than the MAX value of the packet size, the variable length packet is set to “NULL” according to the MAX value. The packet monitoring system according to claim 8, wherein the packet monitoring system is filled with information. The communication path connecting the transmission side terminal and the reception side terminal is aggregated by the first relay apparatus, the aggregated communication path is connected to the second relay apparatus, and the second relay apparatus is connected to the reception side terminal A packet monitoring method for monitoring a packet loss in a network by a network management system,
In the first relay device, a forward error correction code is performed between the headers of a plurality of packets related to communication between the transmission side terminal and the reception side terminal, and the result of the code operation is converted into a redundant packet to generate the plurality of A first procedure for transmitting to the second relay device together with a packet of:
The second relay device transmits the plurality of packets to the receiving terminal and forward error correction decodes between the redundant packet and the plurality of packets received from the first relay device, A second procedure for notifying the network management system of the result of the correction decoding;
A packet monitoring method comprising:   A third relay device that relays between the first relay device and the second relay device, wherein the redundant packet and the plurality of packets received from the first relay device are the second relay device. And a third procedure of forward error correcting decoding between the redundant packet and the plurality of packets, and notifying a calculation result of the correcting decoding to the network management system. Item 11. The packet monitoring method according to Item 10.   In the third procedure, a forward error correction code is performed between the headers of the plurality of packets received from the first relay device, and the result of the code operation is converted into a redundant packet and the second packet together with the plurality of packets. The packet monitoring method according to claim 11, further comprising a procedure of transmitting to the relay apparatus. The first procedure is:
In the first relay device,
A packet receiving procedure for receiving the plurality of packets from the transmitting terminal;
Storing the received plurality of packets;
A forward error correction code between the headers of the plurality of stored packets, and an FEC code calculation procedure for converting the result of the code calculation into a redundant packet;
The plurality of packets from the packet reception procedure and the redundant packet from the FEC code calculation procedure are respectively received, and a second header having information relating to the code calculation is added to each of the plurality of packets and the redundant packet. An encapsulation procedure to
A packet transmission procedure for transmitting the packet transmitted from the encapsulation procedure to the second relay device or the third relay device;
The packet monitoring method according to any one of claims 10 to 12, further comprising: The second procedure is:
In the second relay device,
A packet reception procedure for receiving the plurality of packets and the redundant packet from the first relay device or the third relay device;
A decapsulation procedure for reading a second header of the plurality of packets;
A procedure for storing the plurality of packets and the redundant packet received by the packet reception procedure;
FEC decoding operation procedure for forward error correction decoding between the stored redundant packet and the plurality of packets;
A packet loss monitoring procedure for notifying the network management system of the operation result of the correction decoding;
A packet transmission procedure for receiving a packet from the decapsulation procedure and transmitting the received packet to the receiving terminal;
With
The packet monitoring method according to claim 13, wherein the decapsulation procedure transmits only the plurality of packets to the packet transmission procedure. The third procedure is:
In the third relay device,
A packet reception procedure for receiving the plurality of packets and the redundant packet from the first relay device;
A procedure for storing the plurality of packets and the redundant packet received by the packet reception procedure;
FEC decoding operation procedure for forward error correction decoding between the stored redundant packet and the plurality of packets;
A packet loss monitoring procedure for notifying the network management system of the operation result of the correction decoding;
A packet transmission procedure for receiving the plurality of packets and the redundant packet from the packet reception procedure, and transmitting the received packet to the receiving terminal;
The packet monitoring method according to claim 14, further comprising: The third procedure is:
The third relay apparatus further comprises an FEC code calculation procedure for performing forward error correction code between the headers of the plurality of packets and converting the result of the code calculation into a redundant packet.
The packet monitoring method according to claim 15, wherein in the packet transmission procedure, the redundant packet is transmitted to the second relay device. The first procedure or the third procedure is:
17. The forward error correction code according to claim 10, wherein the header is a part or all of information bytes of a predetermined packet including a header related to a network protocol in the plurality of packets. The packet monitoring method according to any one of claims. The first procedure or the third procedure is:
When forward error correction coding is performed on all information bytes of the variable length packet including the header, if the variable length packet is equal to or smaller than the MAX value of the packet size, the variable length packet is set to “NULL” according to the MAX value. The packet monitoring method according to claim 17, wherein the packet monitoring method is filled with information. The communication path connecting the transmission side terminal and the reception side terminal is aggregated by the first relay apparatus, the aggregated communication path is connected to the second relay apparatus, and the second relay apparatus is connected to the reception side terminal A packet monitoring program for monitoring a packet loss in a network by a network management system,
A forward error correction code is performed between the headers of a plurality of packets related to communication between the transmission side terminal and the reception side terminal, and the result of the code operation is converted into a redundant packet, together with the plurality of packets, the second relay Causing the first relay device to execute a first process to be transmitted to the device;
Forward error correction decoding is performed between the redundant packet and the plurality of packets transmitted from the first relay apparatus and the plurality of packets to the receiving side terminal, and a calculation result of the correction decoding is obtained from the network A packet monitoring program that causes the second relay device to execute a second process of notifying the management system.   A third relay device that relays between the first relay device and the second relay device, wherein the redundant packet and the plurality of packets received from the first relay device are the second relay device. And forward error correction decoding between the redundant packet and the plurality of packets, and a third process of notifying the network management system of the operation result of the correction decoding is executed to the third relay device The packet monitoring program according to claim 19, wherein:   In the third process, a forward error correction code is performed between the headers of the plurality of packets received from the first relay device, the result of the code operation is converted into a redundant packet, and the second packet is transmitted together with the plurality of packets. 21. The packet monitoring program according to claim 20, further causing the third relay device to execute a process of transmitting to the relay device. The first process includes
A packet receiving process for receiving the plurality of packets from the transmitting terminal;
Processing to store the received plurality of packets;
FEC code calculation processing for performing a forward error correction code between the headers of the plurality of stored packets and converting the result of the code calculation into redundant packets;
The plurality of packets from the packet reception process and the redundant packet from the FEC code calculation process are respectively received, and a second header having information on the code calculation is added to each of the plurality of packets and the redundant packet. Encapsulation processing,
A packet transmission process for transmitting the packet transmitted from the encapsulation process to the second relay apparatus or the third relay apparatus;
The packet monitoring program according to any one of claims 19 to 21, wherein the first relay device is executed. The second process includes
A packet reception process for receiving the plurality of packets and the redundant packet from the first relay device or the third relay device;
A decapsulation process for reading a second header of the plurality of packets;
A process of storing the plurality of packets and the redundant packet received by the packet reception process;
FEC decoding arithmetic processing for performing forward error correction decoding between the stored redundant packet and the plurality of packets;
A packet loss monitoring process for notifying the network management system of the operation result of the correction decoding;
A packet transmission process for receiving a packet from the decapsulation process and transmitting the received packet to the receiving terminal;
To the second relay device,
The packet monitoring program according to claim 22, wherein in the decapsulation process, only the plurality of packets are transmitted to the packet transmission process. The third process includes
A packet reception process for receiving the plurality of packets and the redundant packet from the first relay device;
A process of storing the plurality of packets and the redundant packet received by the packet reception process;
FEC decoding arithmetic processing for performing forward error correction decoding between the stored redundant packet and the plurality of packets;
A packet loss monitoring process for notifying the network management system of the operation result of the correction decoding;
A packet transmission process for receiving the plurality of packets and the redundant packet from the packet reception process, and transmitting the received packet to the receiving terminal;
24. The packet monitoring program according to claim 23, wherein the third relay device is executed. The third process includes
Forward error correcting code between the headers of the plurality of packets, and causing the third relay device to further execute FEC code operation processing for converting the result of the code operation into redundant packets,
The packet monitoring program according to claim 24, wherein the packet transmission process transmits the redundant packet to the second relay device. The first process or the third process is:
26. The forward error correction code according to claim 19, wherein the header is a part or all of information bytes of a predetermined packet including a header related to a network protocol in the plurality of packets. The packet monitoring program according to any one of claims. The first process or the third process is:
When forward error correction coding is performed on all information bytes of the variable length packet including the header, if the variable length packet is equal to or smaller than the MAX value of the packet size, the variable length packet is set to “NULL” according to the MAX value. 27. The packet monitoring program according to claim 26, wherein the packet monitoring program is filled with information.

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