JP2011114380A - Communication system, transmitter, receiver, communication device, transmission line quality estimating method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure a high-speed bit error rate in a packet transmission network. <P>SOLUTION: The communication system includes a transmitter for transmitting packets and a receiver for receiving the packets from the transmitter through a transmission line. The transmitter has a notification packet creation means to create a notification packet indicative of the number of transmission packets to be transmitted to the receiver as one of the transmission packets and a transmission means to transmit the transmission packets to the receiver through the transmission line. The receiver has a reception means to receive the transmission packets through the transmission line, a first measurement means to sum up the respective numbers of bits in the received transmission packets to measure the number of received bits, a second measurement means to measure the number of received packets which is the number of received transmission packets, and a calculation means to calculate a bit error rate of the transmission line based on the number of received bits, the number of received packets, and the number of transmission packets shown by the notification packet when the notification packet is received. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication system, a transmission device, a reception device, a communication device, a transmission path quality estimation method, and a program.

  Network service providers need to constantly monitor and manage the quality of transmission lines in order to maintain and provide high-quality services.

  In recent years, various services are being provided on packet networks. For this reason, network service providers are moving to reconstruct transmission networks that have been composed of SONET / SDH (Synchronous Optical NETwork / Synchronous Digital Hierarchy) into packet-based transmission networks in order to increase the efficiency of network bandwidth usage. There is.

When transmitting packets over a transmission network such as SONET / SDH, the bit error rate of the transmission path can be increased by detecting bit errors using the OAM (Operation, Administration and Maintenance) function of SONET / SDH. It was possible to monitor and manage. The bit error rate is generally calculated by the following (Equation 1).
Bit error rate = number of error bits / number of transmission bits (Formula 1)
If packets are directly accommodated using Ethernet (registered trademark) as the physical layer of the network, the SONET / SDH function cannot be used. Therefore, the quality of the transmission path is monitored and managed by the OAM function of SONET / SDH It is not possible.

  As a method for monitoring the quality of a transmission line provided in a high-speed Ethernet having a communication speed of 10 Gb / s or higher, there is a bit error rate measurement method described in Non-Patent Document 1 or Non-Patent Document 2.

  In these methods, the Ethernet signal is divided into 64 bits, a 2-bit “01” or “10” header is attached to the 64-bit information, and the bit error in the header is measured, so that the bit The error rate is measured. That is, in these methods, only a bit error occurring in 2 bits of the header portion in 66 bits can be detected, and a bit error occurring in 64 bits of the other payload portions cannot be detected.

In general, when a bit error rate of 10 ^−N is detected, the number of errors is measured for a bit string of about 10 ^{N + 2} bits in order to ensure detection accuracy.

Therefore, in the method shown in Non-Patent Document 1 or Non-Patent Document 2, for example, in order to detect that the bit error rate is worse than 10 ^{−9 in} Ethernet with a communication speed of 100 Gb / s, 10 ¹¹ bits need to be monitored for errors. In these methods, only 2 bits out of 66 bits can be monitored for errors. For this reason, in these methods, as shown in the following (Formula 2), a measurement time of 30 seconds or more is required.
10 ¹¹ [bit] × (66/2) / (103.125 × 10 ⁹ ) [bps] = 33 [seconds] (Formula 2)

IEEE802.3ae, "Carrier Sense Multiple Access with Collision Detection (CSMA / CD) Access Method and Physical Layer Specifications Amendment 1: Media Access Control (MAC) Parameters, Physical Layers, and Management Parameters for 10 Gb / s Operation". IEEE802.3ba, "Carrier Sense Multiple Access with Collision Detection (CSMA / CD) Access Method and Physical Layer Specifications Amendment: Media Access Control Parameters, Physical Layers and Management Parameters for 40 Gb / s and 100 Gb / s Operation".

  In the technique described in Non-Patent Document 1 or Non-Patent Document 2, the number of bits to be monitored for bit errors is only 2 bits out of 66 bits. For this reason, the technique described in Non-Patent Document 1 or Non-Patent Document 2 has a problem that the measurement time is 33 times longer than when bit errors are monitored for all bits.

  An object of the present invention is to provide a communication system, a transmission device, a reception device, a communication device, a transmission path quality estimation method, and a program that can solve the above-described problems.

The communication system of the present invention is a communication system comprising: a transmission device that transmits a packet; and a reception device that receives a packet transmitted from the transmission device via a transmission path,
The transmitter is
A notification packet creating means for creating a notification packet indicating the number of transmission packets transmitted to the receiving device as one of the transmission packets;
Transmitting means for transmitting the transmission packet to the receiving device via the transmission path,
The receiving device is:
Receiving means for receiving the transmission packet via the transmission path;
First measuring means for measuring the number of received bits by adding the number of bits of each transmission packet received by the receiving means;
Second measuring means for measuring the number of received packets, which is the number of transmitted packets received by the receiving means;
When the receiving unit receives the notification packet, the bit error rate of the transmission path is obtained based on the number of transmission packets indicated in the notification packet, the number of received bits, and the number of received packets. Calculating means.

The transmitting device of the present invention is a transmitting device that transmits a packet to a receiving device via a transmission path,
A notification packet creating means for creating a notification packet indicating the number of transmission packets transmitted to the receiving device as one of the transmission packets;
Transmitting means for transmitting the transmission packet to the receiving device via the transmission path.

The receiving device of the present invention is a receiving device that receives a transmission packet transmitted from a transmitting device via a transmission path,
Receiving means for receiving the transmission packet via the transmission path;
First measuring means for measuring the number of received bits by adding the number of bits of each transmission packet received by the receiving means;
Second measuring means for measuring the number of received packets, which is the number of transmitted packets received by the receiving means;
When the reception unit receives a notification packet indicating the number of transmission packets transmitted from the transmission device via the transmission path, the number of transmission packets indicated by the notification packet and the reception bit And a calculating means for obtaining a bit error rate of the transmission path based on the number and the number of received packets.

  A communication apparatus according to the present invention includes the transmission apparatus and the reception apparatus.

The transmission path quality estimation method of the present invention is a transmission path quality estimation method in a communication system comprising: a transmission apparatus that transmits a packet; and a reception apparatus that receives the packet transmitted from the transmission apparatus via the transmission path. There,
A notification packet creation step in which the transmission device creates a notification packet indicating the number of transmission packets transmitted to the reception device as one of the transmission packets;
A transmitting step in which the transmitting device transmits the transmission packet to the receiving device via the transmission path;
A receiving step in which the receiving device receives the transmission packet via the transmission path;
A first measuring step of measuring the number of received bits by adding the number of bits of each of the received transmission packets;
A second measuring step of measuring the number of received packets, which is the number of transmitted packets received;
When the notification packet is received, a calculation step of obtaining a bit error rate of the transmission path based on the number of transmission packets indicated in the notification packet, the number of received bits, and the number of received packets And comprising.

The program of the present invention provides a transmission device that transmits a packet to a reception device via a transmission path.
Notification packet creating means for creating a notification packet indicating the number of transmission packets transmitted to the receiving apparatus as one of the transmission packets, and transmitting means for transmitting the transmission packet to the receiving apparatus via the transmission path To function as.

The program of the present invention provides a receiving device that receives a transmission packet transmitted from a transmitting device via a transmission path,
Receiving means for receiving the transmission packet via the transmission path;
First measuring means for measuring the number of received bits by adding the number of bits of each transmission packet received by the receiving means;
A second measuring unit that measures the number of received packets that is the number of transmitted packets received by the receiving unit; and the receiving unit that transmits a notification packet indicating the number of transmitted packets transmitted from the transmitting device, Calculation means for obtaining a bit error rate of the transmission path based on the number of transmission packets indicated in the notification packet, the number of received bits, and the number of received packets when received via the transmission path To function as.

  According to the present invention, it is possible to quickly measure the bit error rate even in a packet transmission network.

It is a block diagram of the communication system of 1st Embodiment of this invention. 6 is an explanatory diagram of a packet multiplexing unit 105. FIG. FIG. 10 is a diagram for explaining an operation at the time of packet reception by the packet multiplexing unit 105. 6 is a diagram for explaining the operation of the packet multiplexing unit 105 when transmission of a packet being transmitted at the transmission port 101 is completed and the transmission port 101 becomes usable. FIG. 7 is a diagram for explaining the operation of a bit error rate calculation unit 207. FIG. It is a table | surface explaining the precision of the bit error rate measurement method. It is a block diagram of the communication system of 2nd Embodiment of this invention. 4 is a block diagram of a dummy packet destruction unit 106. FIG. 6 is a diagram for explaining the operation of a dummy packet destruction unit 106. FIG.

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

(First embodiment)
FIG. 1 is a block diagram showing a communication system including a transmission device 100 and a reception device 200 as a first embodiment of the present invention. Note that the transmission device 100 and the reception device 200 may be built in one communication device.

  In FIG. 1, the transmission device 100 transmits a packet to the reception device 200. The receiving apparatus 200 receives the packet transmitted from the transmitting apparatus 100 via the transmission path 300.

  The transmission device 100 includes a transmission port 101, a transmission packet number measurement unit (hereinafter simply referred to as “measurement unit”) 102, a transmission packet number notification packet creation unit (hereinafter simply referred to as “creation unit”) 103, A dummy packet generation unit (hereinafter simply referred to as “generation unit”) 104 and a packet multiplexing unit (hereinafter simply referred to as “multiplexing unit”) 105 are included. The measurement unit 102 and the creation unit 103 are included in the notification packet creation unit 10. The transmission port 101 and the multiplexing unit 105 are included in the transmission unit 11.

  The receiving apparatus 200 includes a reception port 201, a packet error detection unit (hereinafter simply referred to as “detection unit”) 202, a received bit number measurement unit (hereinafter simply referred to as “measurement unit”) 203, and the number of received packets. Measurement unit (hereinafter simply referred to as “measurement unit”) 204, transmission packet number notification packet extraction unit (hereinafter simply referred to as “extraction unit”) 205, dummy packet discard unit (hereinafter simply referred to as “discard unit”) 206) and a bit error rate calculation unit (hereinafter simply referred to as "calculation unit") 207. The extraction unit 205 and the calculation unit 207 are included in the calculation unit 20.

  Notification packet creation unit 10 can be generally referred to as notification packet creation means. The notification packet creation unit 10 creates a notification packet indicating the number of transmission packets to be transmitted to the receiving device 200 as one of the transmission packets (a packet belonging to the transmission packet).

  Transmitting unit 11 can be generally referred to as transmitting means. The transmission unit 11 transmits the transmission packet to the reception device 200 via the transmission path 300.

  The transmission port 101 transmits the transmission packet to the reception device 200 via an external physical line, that is, the transmission path 300. The transmission port 101 transmits, for example, an Ethernet format transmission packet to the reception device 200 via the transmission path 300.

  Measuring unit 102 can generally be referred to as third measuring means.

  The measuring unit 102 measures the number of transmission packets transmitted by the transmission device 100 (specifically, the transmission port 101). The measuring unit 102 may measure the number of transmitted packets for each path or for each packet destination. The path is distinguished by, for example, VLAN (Virtual LAN) in Ethernet or LSP (Label Switched Path) in MPLS (Multi-Protocol Label Switching). The measurement unit 102 transmits the measurement result (the number of transmission packets) to the creation unit 103.

  Creation unit 103 can generally be referred to as creation means.

  The creation unit 103 periodically creates a notification packet (hereinafter referred to as “transmission packet number notification packet”) for notifying the reception device 200 of the number of transmission packets, using the measurement result of the measurement unit 102. The transmission packet number notification packet can be generally referred to as a notification packet.

  As the transmission packet count notification packet, for example, a CCM (Continuity Check Message) packet or an LMM (Loss Measurement Message) packet defined in ITU-T (International Telecommunication Union-Telecommunications Standardization Sector) Y.1731 may be used. The transmission packet number notification packet indicates the number of transmission packets transmitted to the receiving apparatus 200.

  The creation unit 103 transmits the transmission packet number notification packet to the multiplexing unit 105.

  Generation unit 104 can be generally referred to as generation means.

  The generation unit 104 generates a dummy packet that belongs to the transmission packet. The dummy packet is used to measure the bit error rate of the transmission line 300. Note that in a network that can specify the priority (QoS) of a packet, the priority of the dummy packet may be the lowest priority.

  The generation unit 104 adds information indicating the dummy packet (dummy packet identification information) to the dummy packet. For example, in Ethernet, a TEST packet defined in ITU-T Y.1731 may be used as a dummy packet. When a TEST packet is used as a dummy packet, the OpCode value of the TEST packet or the Type value of TEST TLV is used as dummy packet identification information. The dummy packet is not limited to the Ethernet TEST packet, and a test packet included in each protocol may be used as the dummy packet.

  The generation unit 104 may generate a dummy packet for each path, each packet destination, or each source / destination pair. The path is distinguished by, for example, a VLAN in Ethernet or an LSP in MPLS. In Ethernet, the packet length of the dummy packet may be 64 bytes, which is the minimum packet length in Ethernet.

  The generation unit 104 may generate dummy packets at regular time intervals. For example, the operation is to generate N dummy packets per second. Alternatively, the generation unit 104 may monitor the input state of the packet to the multiplexing unit 105 and generate a dummy packet when there is a vacancy in the input of the packet to the multiplexing unit 105.

  The generation unit 104 transmits the dummy packet to the multiplexing unit 105.

  The multiplexing unit 105 includes a buffer that temporarily stores transmission packets. The multiplexing unit 105 receives a data packet transmitted from the transmission device 100 from another device (for example, an information processing device). Further, the multiplexing unit 105 receives the transmission packet number notification packet from the creation unit 103. In addition, the multiplexing unit 105 receives a dummy packet from the generation unit 104.

  The multiplexing unit 105 multiplexes the data packet, the dummy packet, and the transmission packet number notification packet. In the present embodiment, the multiplexing unit 105 time-division multiplexes the data packet, the dummy packet, and the transmission packet number notification packet. Note that the multiplexing method used by the multiplexing unit 105 is not limited to time division multiplexing and can be changed as appropriate. The multiplexing unit 105 transmits each of the data packet, the dummy packet, and the transmission packet number notification packet to the measurement unit 102 as a transmission packet.

  The measurement unit 102 measures the number of transmission packets transmitted from the multiplexing unit 105 and transmits the transmission packets to the transmission port 101. The transmission port 101 transmits the transmission packet transmitted from the measurement unit 102 to the reception device 200 via the transmission path 300.

  That is, the transmission unit 11 receives a data packet from another device, receives a dummy packet from the generation unit 104, and receives a transmission packet number notification packet from the creation unit 103. The transmission unit 11 time-division multiplexes the data packet, the dummy packet, and the transmission packet number notification packet. To the receiving device 200. The multiplexing method used by the transmission unit 11 is not limited to time division multiplexing and can be changed as appropriate.

  In the present embodiment, the transmission unit 11 transmits packets other than dummy packets (data packets and transmission packet number notification packet) with higher priority than dummy packets.

  In the present embodiment, the transmission unit 11 transmits the transmission packet number notification packet with priority over packets (data packets and dummy packets) other than the transmission packet number notification packet among the transmission packets.

  The transmission device 100 is a computer, for example, and functions as the notification packet creation unit 10, the transmission unit 11, and the generation unit 104 by reading and executing a program recorded on a computer-readable recording medium. . Note that each of the notification packet creation unit 10, the transmission unit 11, and the generation unit 104 may be realized by dedicated hardware.

  Reception port 201 can be generally referred to as reception means. The reception port 201 receives a transmission packet from the transmission device 100 via an external physical line, that is, the transmission path 300.

  The detection unit 202 investigates whether there is an error in the transmission packet received by the reception port 201. The detection unit 202 discards the packet in which the error is detected. For example, in Ethernet communication, the detection unit 202 checks the presence or absence of an error by checking the FCS (Frame Check Sequence) value at the end of the packet.

  Measuring unit 203 can be generally referred to as first measuring means.

  The measurement unit 203 measures the number of received bits by adding the number of bits of each transmission packet received at the reception port 201. The measuring unit 203 may measure the number of received bits for each path, for each packet destination, or for each source / destination pair. Note that the measurement unit 203 distinguishes paths by, for example, VLAN in Ethernet or LSP in MPLS.

  Measurement unit 204 can be generally referred to as second measurement means.

  The measuring unit 204 measures the number of transmission packets received by the reception port 201 (hereinafter referred to as “the number of received packets”). The measuring unit 204 may measure the number of received packets for each path, for each packet destination, or for each source / destination pair. Note that the measurement unit 204 distinguishes paths by, for example, a VLAN in Ethernet or an LSP in MPLS.

  The extraction unit 205 identifies the transmission packet number notification packet from the transmission packets received at the reception port 201, and extracts the transmission packet number notification packet. The extraction unit 205 notifies the calculation unit 207 of the transmission packet number notification packet.

  When the calculation unit 207 receives the transmission packet number notification packet, the calculation unit 207 acquires the measurement result (the number of received bits) of the measurement unit 203 at that time and the measurement result (the number of received packets) of the measurement unit 204 at that time To do.

  Arithmetic unit 207 obtains the bit error rate of transmission path 300 based on the number of transmission packets, the number of received bits, and the number of received packets indicated in the transmitted packet number notification packet.

  In this embodiment, every time the operation unit 207 receives a transmission packet number notification packet, the arithmetic unit 207 associates the number of transmission packets, the number of reception bits, and the number of reception packets indicated in the transmission packet number notification packet with each other. And stored in the calculation unit 207.

  When the calculation unit 207 stores the number of transmission packets, the number of received bits, and the number of received packets in association with each other, the information stored when the current transmission packet number notification packet is received and the previous transmission packet number notification packet are received. From the stored information, the bit error rate of the transmission line 300 is calculated.

  Discarding unit 206 can be generally referred to as discarding means. When the number of received bits and the number of received packets for the dummy packet are measured, discarding section 206 discards the dummy packet.

  Calculation unit 20 can be generally referred to as calculation means.

  Upon receiving the transmission packet number notification packet, the calculation unit 20 receives the number of transmission packets indicated by the transmission packet number notification packet, the number of received bits from the measurement unit 203, and the number of received packets from the measurement unit 204. , The bit error rate of the transmission path 300 is obtained. The calculation unit 20 obtains, for example, a value obtained by subtracting the number of received packets from the number of transmitted packets and the number of received bits as the bit error rate of the transmission path 300.

  Note that the receiving device 200 is, for example, a computer, and by reading and executing a program recorded on a computer-readable recording medium, the receiving port 201, the detecting unit 202, the measuring unit 203, the measuring unit 204, and the discarding unit 206 and the calculation unit 20 function. Note that each of the reception port 201, the detection unit 202, the measurement unit 203, the measurement unit 204, the discard unit 206, and the calculation unit 20 may be realized by dedicated hardware.

  FIG. 2 is a block diagram showing the multiplexing unit 105.

  In FIG. 2, a multiplexing unit 105 includes a received packet distribution unit (hereinafter simply referred to as “distribution unit”) 301, a transmission packet number notification packet storage unit (hereinafter simply referred to as “storage unit”) 302, a data Packet storage unit (hereinafter simply referred to as “storage unit”) 303, dummy packet storage unit (hereinafter simply referred to as “storage unit”) 304, and transmission packet selection unit (hereinafter simply referred to as “selection unit”) 305.

  The distribution unit 301 identifies whether the packet received by the multiplexing unit 105 is a transmission packet number notification packet, a data packet, or a dummy packet.

  For example, when a CCM packet or an LMM packet is used as the transmission packet count notification packet, when the packet received by the multiplexing unit 105 is a CCM packet or an LMM packet, the distribution unit 301 105 identifies that the received packet is a transmitted packet count notification packet.

  For example, when the dummy packet identification information is added to the packet received by the multiplexing unit 105, the distribution unit 301 identifies that the packet received by the multiplexing unit 105 is a dummy packet.

  The distribution unit 301 stores the transmission packet number notification packet in the storage unit 302, stores the data packet in the storage unit 303, and stores the dummy packet in the storage unit 304.

  The storage unit 302 stores the transmission packet number notification packet in the order of reception. The storage unit 303 stores the data packets in the order received. The storage unit 304 stores the dummy packets in the order of reception.

  When the transmission port 101 is in a transmittable state, the selection unit 305 alternatively selects a transmission packet to be transmitted next from the packets in the storage units 302 to 304, and selects the selected packet as the measurement unit 102. Output to.

  Next, the operation will be described.

  FIG. 3 is a flowchart for explaining the operation when the multiplexing unit 105 receives a packet.

  When receiving the packet (step S3-1), the distribution unit 301 in the multiplexing unit 105 checks whether the packet (hereinafter referred to as “received packet”) is a transmission packet number notification packet (step S3). -2).

  If the received packet is a transmission packet number notification packet, distribution unit 301 stores the transmission packet number notification packet at the end of the transmission packet number notification packet in storage unit 302 (step S3-3).

  If the received packet is not a transmitted packet count notification packet, the sorting unit 301 confirms whether the received packet is a data packet (step S3-4).

  If the received packet is a data packet, the distribution unit 301 stores the data packet at the end of the data packet in the storage unit 303 (step S3-5).

  If the received packet is not a data packet, the sorting unit 301 confirms whether or not the received packet is a dummy packet (step S3-6).

  If the received packet is a dummy packet, the distribution unit 301 stores the dummy packet at the end of the dummy packet in the storage unit 304 (step S3-7).

  If the received packet is not a dummy packet, the distribution unit 301 determines an error (step S3-8).

  FIG. 4 is a flowchart for explaining the operation of the multiplexing unit 105 when transmission of a transmission packet being transmitted at the transmission port 101 is completed and the transmission port 101 becomes usable.

  The selection unit 305 in the multiplexing unit 105 first checks whether a packet is stored in the storage unit 302 (step S4-2).

  When the packet is stored in the storage unit 302, the selection unit 305 reads the first transmission packet number notification packet of the transmission packet number notification packet stored in the storage unit 302, the transmission packet number notification packet, It transmits from the transmission port 101 via the counting unit 102, and deletes the transmitted packet information from the storage unit 302 (step S4-3).

  If no packet is stored in the storage unit 302, the selection unit 305 confirms whether the packet is stored in the storage unit 303 (step S4-4).

  When the packet is stored in the storage unit 303, the selection unit 305 reads the first data packet among the data packets stored in the storage unit 303, and transmits the data packet to the transmission port 101 via the counting unit 102. The information of the transmitted packet is deleted from the storage unit 303 (step S4-5).

  When the packet is not stored in the storage unit 303, the selection unit 305 confirms whether the packet is stored in the storage unit 304 (step S4-6).

  When the packet is stored in the storage unit 304, the selection unit 305 reads the first dummy packet among the dummy packets stored in the storage unit 304, and transmits the dummy packet to the transmission port 101 via the counting unit 102. And the transmitted packet information is deleted from the storage unit 304 (step S4-7).

  If no packet is stored in the storage unit 304, the selection unit 305 waits until a packet is received (step S4-8).

  FIG. 5 is a flowchart for explaining the operation of the calculation unit 207.

  The calculation unit 207 waits for the information of the transmission packet number notification packet to be notified from the extraction unit 205 (step S5-1).

  After that, when the arithmetic operation unit 207 receives the N (N is an integer equal to or greater than 1) number of transmission packet notification packets (step S5-2), the number of transmission packets indicated in the Nth transmission packet number notification packet Information TxPC [N], received bit number information RxBC [N] measured by the measuring unit 203 at that time, and received packet number information RxPC [N] measured by the measuring unit 204 at that time, and these Are stored in association with each other (step S5-3).

  After that, the calculation unit 207 transmits the received bit number information RxBC [N-1], the received packet number information RxPC [N-1], which was saved when the previous (N-1th) transmitted packet number notification packet was received, Packet number information TxPC [N-1] is read (step S5-4).

Thereafter, the calculation unit 207 calculates the bit error rate according to (Equation 3) below (step S5-5).
Bit error rate = [(TxPC [N] -TxPC [N-1])-(RxPC [N] -RxPC [N-1])] / (RxBC [N] -RxBC [N-1]) (Formula 3 )
After that, the calculation unit 207 compares whether the bit error rate calculated in step S5-5 is larger than the bit error rate set in advance as a threshold (step S5-6), and calculated in step S5-5. If the bit error rate is larger than the threshold value, an alarm is issued (step S5-7), and if the bit error rate is smaller than the threshold value, the process proceeds to step S5-8.

  In step S5-8, the operation unit 207 increases the value of N by 1, returns to step S5-1, and waits for reception of the transmission packet number notification packet.

  Here, the validity of the calculation of the bit error rate according to (Equation 3) will be described.

  The numerator of (Equation 3) is the difference between the number of transmitted packets (TxPC [N] -TxPC [N-1]) and the number of received packets (RxPC [N] -RxPC [N-1]) over a certain period. This represents the number of lost packets.

In an environment where the bit error rate is relatively low with a bit error rate of 10 ⁻⁵ or less, the probability that an error of 2 bits or more occurs in a single packet is small and can be approximated as the number of lost packets≈the number of bit errors.

The denominator of (Expression 3) is the number of received bits in a certain period. The denominator of (Equation 1) is the number of transmitted bits, but in an environment with relatively few bit errors with a bit error rate of 10 ^-5 or less, the number of lost packets is small, and the number of transmitted bits can be approximated to the number of received bits. .

FIG. 6 is a table showing the measurement error of the present method for each packet length in the bit error rate range of 10 ⁻⁵ to 10 ⁻¹⁰ . Even when the bit error rate with the largest error is 10 ^-5 and the packet length is 1518 bytes, the error is less than 10%. Note that 1518 bytes is the longest packet length in Ethernet.

  Note that the present embodiment may be modified as follows.

  In receiving apparatus 100, creation unit 103 resets the measurement value of measurement unit 102 to “0” each time a transmission packet number notification packet is created. The measurement value of the measurement unit 102 does not include the number of transmission packet number notification packets created this time, but includes the number of transmission packet number notification packets created last time. The number of transmission packet number notification packets created this time and the number of transmission packet number notification packets created last time are both 1. For this reason, the measurement value of the measurement unit 102 substantially indicates the number of transmission packets (including the transmission packet number notification packet created this time) transmitted after the previous transmission packet number notification packet was transmitted. It becomes.

  In the receiving device 200, the arithmetic unit 207 reads the measurement value (the number of received bits) of the measurement unit 203 and the measurement value (the number of received packets) of the measurement unit 204 each time it receives a transmission packet number notification packet, and then performs measurement. The measurement values of the units 203 and 204 are reset to “0”. Every time the calculation unit 207 receives a transmission packet number notification packet, the value obtained by subtracting the read measurement value (the number of reception packets) of the measurement unit 204 from the number of transmission packets indicated in the transmission packet number notification packet Is divided by the measurement result (the number of received bits) of the measured measurement unit 203 to obtain the bit error rate of the transmission line 300.

  In this case, the calculation unit 207 can calculate the bit error rate of the transmission line 300 without using the previous measurement value. Therefore, the calculation unit 207 does not need to store the previous measurement value.

  According to the present embodiment, in the transmission device 100, the notification packet creation unit 10 creates a transmission packet number notification packet indicating the number of transmission packets transmitted to the reception device 200 as one of the transmission packets, and the transmission unit 11 transmits the transmission packet to the receiving apparatus 200 via the transmission path 300.

  In the reception device 200, the reception port 201 receives a transmission packet via the transmission path 300, and the measurement unit 203 measures the number of reception bits by adding the respective number of bits of the received transmission packet, and measures it. Unit 204 measures the number of received packets, which is the number of received transmission packets.

  Then, the calculation unit 20 calculates the bit error rate of the transmission path 300 based on the number of transmission packets, the number of received bits, and the number of received packets indicated in the transmission packet number notification packet. The calculation unit 20 obtains, for example, a value obtained by subtracting the number of received packets from the number of transmitted packets and the number of received bits as the bit error rate of the transmission path 300.

  Therefore, according to the present embodiment, the bit error rate can be quickly measured in the packet transmission network.

In order to detect that the bit error rate of the transmission line is worse than 10 ⁻⁹ , it is necessary to measure the number of errors of 10 ¹¹ bits.

According to the present embodiment, for example, when the utilization rate of the physical band is almost 100%, in Ethernet having a communication speed of 100 Gbps, the number of errors for 10 ¹¹ bits is measured in 1.2 seconds, and the bit error rate is It can be detected in 1.2 seconds that it is worse than 10 ^-9 . In the technology described in Non-Patent Document 1 or Non-Patent Document 2, it took 30 seconds or more to detect that the bit error rate was worse than 10 ^{-9 in} Ethernet with a communication speed of 100 Gbps. In this embodiment, the speed can be increased by nearly 30 times compared to the technique described in Non-Patent Document 1 or Non-Patent Document 2.

  Note that the above-described effect is that a communication system including the transmission device 100 including the notification packet creation unit 10 and the transmission unit 11, and the reception device 200 including the reception port 201, the measurement unit 203, the measurement unit 204, and the calculation unit 20. But it is played.

  In the present embodiment, the transmission device 100 further includes a generation unit 104 that generates a dummy packet as at least one of the transmission packets. In this case, the insertion of the dummy packet makes it possible to make the utilization rate of the physical bandwidth almost 100%, and prevent the bit error rate measurement time from becoming long.

  In the present embodiment, the transmission unit 11 transmits packets other than dummy packets out of transmission packets with priority over dummy packets. In this case, it is possible to prevent transmission of other packets from being delayed due to transmission of dummy packets.

  In the present embodiment, the transmission unit 11 transmits the transmission packet number notification packet with priority over packets other than the transmission packet number notification packet among the transmission packets. In this case, measurement of the bit error rate of the transmission line 300 can be performed with priority.

  In the present embodiment, the receiving apparatus 200 includes a discard unit 206 that discards the dummy packet when the number of received bits and the number of received packets for the dummy packet are measured. In this case, it becomes possible to discard dummy packets that are no longer needed.

  In the present embodiment, the generation unit 104 generates a TEST frame described in ITU-T Y.1731 as a dummy packet. In this case, the TEST frame can be used as a dummy packet.

(Second Embodiment)
In Ethernet, when the transmission port 101 starts transmitting a packet, it cannot transmit the next packet until the transmission of the packet is completed. Therefore, in the first embodiment, there is a problem that transmission of a data packet may be delayed due to transmission of a dummy packet.

  For example, in the first embodiment, when the packet length of the dummy packet is set to 64 bytes, which is the minimum packet length in Ethernet, jitter of 62 nanoseconds maximum occurs in Ethernet with a communication speed of 10 Gb / s. Since jitter hinders improvement in accuracy in time synchronization and clock synchronization, it is desirable that jitter is small.

  The second embodiment of the present invention solves the problems that occur in the first embodiment.

  FIG. 7 is a block diagram showing a communication system including the transmission device 100A and the reception device 200 as the second embodiment of the present invention. Note that the transmission device 100A and the reception device 200 may be incorporated in one communication device. In FIG. 7, the same components as those shown in FIG.

  In FIG. 7, the second embodiment is different from the first embodiment in that the transmitting apparatus 100 </ b> A has a dummy packet destruction unit (hereinafter simply referred to as “destruction unit”) 106. The configuration of other parts of the transmission device 100A and the configuration of the reception device 200 are the same as those in the first embodiment.

  FIG. 8 is a block diagram showing the destruction unit 106.

  In FIG. 8, the destruction unit 106 includes a transmitting packet monitoring unit (hereinafter simply referred to as “monitoring unit”) 401, a packet multiplexing unit monitoring unit (hereinafter simply referred to as “monitoring unit”) 402, error detection, and the like. Information calculation unit (hereinafter simply referred to as “calculation unit”) 403, packet end signal insertion unit (hereinafter simply referred to as “insertion unit”) 404, transmission packet number subtraction unit (hereinafter simply referred to as “subtraction unit”) 405).

  Destruction unit 106 can be generally referred to as dummy packet control means.

  The destruction unit 106 interrupts transmission of a dummy packet by the transmission port 101 when it is necessary to transmit another packet (transmission packet number notification packet, data packet) while the transmission port 101 is transmitting a dummy packet. Then, the transmission port 101 is made to transmit another packet.

  Further, when interrupting transmission of dummy packets by the transmission port 101, the destruction unit 106 subtracts 1 from the number of transmission packets (specifically, dummy packets) measured by the measurement unit 102.

  In addition, when the destruction unit 106 interrupts transmission of the dummy packet by the transmission port 101, the transmission unit 101 transmits erroneous error detection information added to the end of the transmitted portion of the dummy packet. Thereafter, transmission of the untransmitted portion of the dummy packet by the transmission port 101 is stopped.

  The monitoring unit 401 identifies whether the packet transmitted from the multiplexing unit 105 is a dummy packet.

  The monitoring unit 402 monitors the presence / absence of packets in the storage unit 303 and the storage unit 302 in the multiplexing unit 105. When the packet arrives at storage unit 303 or storage unit 302 in multiplexing unit 105 and the packet being transmitted is a dummy packet, monitoring unit 402 instructs insertion unit 404 to transmit a packet end signal.

  The calculation unit 403 calculates error detection information for the packet being transmitted. For example, in the case of Ethernet, the calculation unit 403 calculates a 32-bit CRC (Cyclic Redundancy Check).

  The insertion unit 404 transmits a packet end signal to the transmission port 101 according to a command from the monitoring unit 402.

  When a protocol that includes error detection information in the packet, such as Ethernet, is used, the calculation unit 403 causes an erroneous error to be added to the end of the transmitted portion of the dummy packet whose transmission has been interrupted. The insertion unit 404 may transmit the packet termination signal to the transmission port 101 after calculating the detection information and transmitting the error detection information to the transmission port 101. For example, the calculation unit 403 transmits error detection information obtained by adding 1 to the CRC as erroneous error detection information.

  After transmitting the packet end signal, the inserting unit 404 notifies the subtracting unit 405 that the dummy packet has been destroyed.

  When notified from the insertion unit 404 that the dummy packet has been destroyed, the subtraction unit 405 instructs the measurement unit 102 to subtract one from the number of transmission packets.

  Note that the transmission device 100A is, for example, a computer, and reads and executes a program recorded on a computer-readable recording medium, thereby generating a notification packet creation unit 10, a transmission unit 11, a generation unit 104, and a destruction unit. Functions as 106. Note that each of the notification packet creation unit 10, the transmission unit 11, the generation unit 104, and the destruction unit 106 may be realized by dedicated hardware.

  FIG. 9 is a flowchart for explaining the operation of the monitoring unit 402 when the transmission port 101 is transmitting a packet.

  In steps S9-1 and S9-2, the monitoring unit 402 checks whether there is a packet in the storage unit 302 in the multiplexing unit 105. If there is no packet in the storage unit 302, the monitoring unit 402 proceeds to step S9-3. If there is a packet in the storage unit 302, the monitoring unit 402 proceeds to step S9-4.

  In step S9-3, the monitoring unit 402 checks whether there is a packet in the storage unit 303 in the multiplexing unit 105. If there is a packet in the storage unit 303, the monitoring unit 402 proceeds to step S9-4. If there is no packet in the storage unit 303, the monitoring unit 402 returns to step S9-1 and continues monitoring of the multiplexing unit 105.

  In step S9-4, the monitoring unit 402 determines whether the packet being transmitted is a dummy packet based on information from the monitoring unit 401. If the packet being transmitted is a dummy packet, the monitoring unit 402 proceeds to step S9-5. If the packet being transmitted is not a dummy packet, the monitoring unit 402 returns to step S9-1 and continues monitoring of the multiplexing unit 105.

  In step S9-5, the monitoring unit 402 instructs the insertion unit 404 to destroy the dummy packet, and interrupts and destroys the transmission of the dummy packet being transmitted.

  When transmission of the dummy packet is interrupted, the transmission port 101 becomes ready to transmit the next packet, and packets other than the dummy packet stored in the multiplexing unit 105 are transmitted from the transmission port 101 (step S9). -6).

  Note that this embodiment may also be modified as follows.

  In receiving apparatus 100A, creation unit 103 resets the measurement value of measurement unit 102 to “0” each time a transmission packet number notification packet is created. The measurement value of the measurement unit 102 does not include the number of transmission packet number notification packets created this time, but includes the number of transmission packet number notification packets created last time. The number of transmission packet number notification packets created this time and the number of transmission packet number notification packets created last time are both 1. For this reason, the measurement value of the measurement unit 102 substantially indicates the number of transmission packets (including the transmission packet number notification packet created this time) transmitted after the previous transmission packet number notification packet was transmitted. It becomes.

  In the receiving device 200, the arithmetic unit 207 reads the measurement value (the number of received bits) of the measurement unit 203 and the measurement value (the number of received packets) of the measurement unit 204 each time it receives a transmission packet number notification packet, and then performs measurement. The measurement values of the units 203 and 204 are reset to “0”. Every time the calculation unit 207 receives a transmission packet number notification packet, the value obtained by subtracting the read measurement value (the number of reception packets) of the measurement unit 204 from the number of transmission packets indicated in the transmission packet number notification packet Is divided by the measurement result (the number of received bits) of the measured measurement unit 203 to obtain the bit error rate of the transmission line 300.

  In this case, the calculation unit 207 can calculate the bit error rate of the transmission line 300 without using the previous measurement value. Therefore, the calculation unit 207 does not need to store the previous measurement value.

  According to the present embodiment, the destruction unit 106 interrupts the transmission of the dummy packet by the transmission port 101 when it is necessary to transmit another packet in the situation where the transmission port 101 is transmitting the dummy packet, The transmission port 101 is made to transmit another packet.

  For this reason, it is possible to reduce the jitter generated by inserting the dummy packet.

  In this embodiment, the destruction unit 106 subtracts 1 from the number of transmission packets measured by the measurement unit 102 when interrupting transmission of dummy packets by the transmission port 101. In this case, the interruption of transmission of the dummy packet can be reflected in the transmission packet number notification packet. For this reason, it becomes possible to prevent the deterioration of the accuracy of the bit error rate of the transmission line 300 due to the interruption of the transmission of the dummy packet.

  In the present embodiment, when the destruction unit 106 interrupts transmission of the dummy packet by the transmission port 101, the destruction unit 106 transmits to the transmission port 101 erroneous error detection information added to the end of the transmitted portion of the dummy packet. After that, the transmission by the transmission port 101 of the untransmitted portion of the dummy packet is stopped. In this case, it becomes easy for the receiving apparatus 200 to determine a transmitted portion of the dummy packet as a packet error.

  In each embodiment described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration.

100, 100A transmitter
101 Transmission port
102 Transmitted packet count measurement unit
103 Transmitted packet count notification packet generator
104 Dummy packet generator
105 Packet multiplexer
106 Dummy packet destruction part
10 Notification packet generator
11 Transmitter
200 Receiver
201 Receive port
202 Packet error detector
203 Received bit count measurement unit
204 Number of received packet counters
205 Transmitted packet count notification packet extractor
206 Dummy packet discard section
207 Bit error rate calculator
20 Calculation unit
300 transmission line
301 Receive packet sorter
302 Transmitted packet count notification packet storage
303 Data packet storage
304 Dummy packet storage
305 Transmission packet selector
401 Transmitting packet monitor
402 Packet multiplexing unit monitoring unit
403 Error detection information calculator
404 End-of-packet signal insertion part
405 Transmission packet subtraction unit

Claims (26)

A communication system comprising: a transmission device that transmits a packet; and a reception device that receives a packet transmitted from the transmission device via a transmission path,
The transmitter is
A notification packet creating means for creating a notification packet indicating the number of transmission packets transmitted to the receiving device as one of the transmission packets;
Transmitting means for transmitting the transmission packet to the receiving device via the transmission path,
The receiving device is:
Receiving means for receiving the transmission packet via the transmission path;
First measuring means for measuring the number of received bits by adding the number of bits of each transmission packet received by the receiving means;
Second measuring means for measuring the number of received packets, which is the number of transmitted packets received by the receiving means;
When the receiving unit receives the notification packet, the bit error rate of the transmission path is obtained based on the number of transmission packets indicated by the notification packet, the number of received bits, and the number of received packets. A communication system comprising: calculation means.   2. The communication system according to claim 1, wherein the calculation unit obtains a value obtained by subtracting the number of received packets from the number of transmitted packets and dividing the value by the number of received bits as a bit error rate of the transmission path.   The communication system according to claim 1, wherein the transmission device further includes a generation unit that generates a dummy packet as at least one of the transmission packets.   The communication system according to claim 3, wherein the transmission unit transmits a packet other than the dummy packet in the transmission packet in preference to the dummy packet.   5. The communication system according to claim 3, wherein the transmission unit transmits the notification packet in preference to packets other than the notification packet among the transmission packets. 6.   6. The reception device according to claim 3, further comprising: a discard unit configured to discard the dummy packet when the number of received bits and the number of received packets for the dummy packet are measured. Communications system.   The transmission device interrupts transmission of the dummy packet by the transmission unit when it is necessary to transmit another transmission packet different from the dummy packet in a situation where the transmission unit is transmitting the dummy packet. The communication system according to any one of claims 3 to 6, further comprising dummy packet control means for causing the transmission means to transmit the other transmission packet. The notification packet creating means includes
Third measuring means for measuring the number of the transmitted packets;
Creating means for creating a packet indicating the measurement result of the third measuring means as the notification packet;
The communication system according to claim 7, wherein the dummy packet control unit subtracts 1 from the number of transmission packets measured by the third measurement unit when the transmission of the dummy packet by the transmission unit is interrupted.   When the transmission of the dummy packet by the transmission unit is interrupted, the dummy packet control unit causes the transmission unit to transmit erroneous error detection information added to the end of the transmitted portion of the dummy packet. Then, the communication system according to claim 7 or 8, wherein transmission by the transmission unit of an untransmitted portion of the dummy packet is stopped.   The communication system according to any one of claims 3 to 9, wherein the generation unit generates a TEST frame described in ITU-T Y.1731 as the dummy packet. A transmitting device that transmits a packet to a receiving device via a transmission path,
A notification packet creating means for creating a notification packet indicating the number of transmission packets transmitted to the receiving device as one of the transmission packets;
A transmission unit configured to transmit the transmission packet to the reception device via the transmission path.   The transmission device according to claim 11, further comprising generation means for generating a dummy packet as at least one of the transmission packets.   The transmission device according to claim 12, wherein the transmission unit transmits a packet other than the dummy packet in the transmission packet in preference to the dummy packet.   The transmission device according to claim 12 or 13, wherein the transmission unit transmits the notification packet in preference to packets other than the notification packet among the transmission packets.   When it is necessary to transmit another transmission packet different from the dummy packet in a situation where the transmission means is transmitting the dummy packet, transmission of the dummy packet by the transmission means is interrupted, and the transmission means The transmission device according to claim 12, further comprising dummy packet control means for transmitting the other transmission packet. The notification packet creating means includes
Third measuring means for measuring the number of the transmitted packets;
Creating means for creating a packet indicating the measurement result of the third measuring means as the notification packet;
The transmission apparatus according to claim 15, wherein the dummy packet control unit subtracts 1 from the number of transmission packets measured by the third measurement unit when the transmission of the dummy packet by the transmission unit is interrupted.   When the transmission of the dummy packet by the transmission unit is interrupted, the dummy packet control unit causes the transmission unit to transmit erroneous error detection information added to the end of the transmitted portion of the dummy packet. Then, the transmission apparatus according to claim 15 or 16, wherein transmission by the transmission unit of an untransmitted portion of the dummy packet is stopped. A receiving device that receives a transmission packet transmitted from a transmitting device via a transmission path,
Receiving means for receiving the transmission packet via the transmission path;
First measuring means for measuring the number of received bits by adding the number of bits of each transmission packet received by the receiving means;
Second measuring means for measuring the number of received packets, which is the number of transmitted packets received by the receiving means;
When the reception unit receives a notification packet indicating the number of transmission packets transmitted from the transmission device via the transmission path, the number of transmission packets indicated by the notification packet and the reception bit And a calculating means for obtaining a bit error rate of the transmission path based on the number of packets and the number of received packets.   19. The receiving apparatus according to claim 18, wherein the calculating means obtains a value obtained by subtracting the number of received packets from the number of transmitted packets and the number of received bits as a bit error rate of the transmission path. A transmission device according to any one of claims 11 to 17,
A communication device comprising: the receiving device according to claim 18. A transmission path quality estimation method in a communication system comprising: a transmission apparatus that transmits a packet; and a reception apparatus that receives a packet transmitted from the transmission apparatus via a transmission path,
A notification packet creation step in which the transmission device creates a notification packet indicating the number of transmission packets transmitted to the reception device as one of the transmission packets;
A transmitting step in which the transmitting device transmits the transmission packet to the receiving device via the transmission path;
A receiving step in which the receiving device receives the transmission packet via the transmission path;
A first measuring step of measuring the number of received bits by adding the number of bits of each of the received transmission packets;
A second measuring step of measuring the number of received packets, which is the number of transmitted packets received;
When the notification packet is received, a calculation step of obtaining a bit error rate of the transmission path based on the number of transmission packets indicated in the notification packet, the number of received bits, and the number of received packets A transmission path quality estimation method comprising:   The transmission path quality according to claim 21, wherein in the calculation step, a value obtained by subtracting the number of received packets from the number of transmission packets divided by the number of received bits is obtained as a bit error rate of the transmission path. Estimation method. A transmitting device that transmits a packet to a receiving device via a transmission path,
Notification packet creating means for creating a notification packet indicating the number of transmission packets transmitted to the receiving apparatus as one of the transmission packets, and transmitting means for transmitting the transmission packet to the receiving apparatus via the transmission path , A program to make it function as.   24. The program according to claim 23, further causing the transmitting device to function as generating means for generating a dummy packet as at least one of the transmitted packets. A receiving device that receives a transmission packet transmitted from a transmitting device via a transmission path,
Receiving means for receiving the transmission packet via the transmission path;
First measuring means for measuring the number of received bits by adding the number of bits of each transmission packet received by the receiving means;
A second measuring unit that measures the number of received packets that is the number of transmitted packets received by the receiving unit; and the receiving unit that transmits a notification packet indicating the number of transmitted packets transmitted from the transmitting device, Calculation means for obtaining a bit error rate of the transmission path based on the number of transmission packets indicated in the notification packet, the number of received bits, and the number of received packets when received via the transmission path , A program to make it function as.   26. The program according to claim 25, wherein the calculating means obtains a value obtained by subtracting the number of received packets from the number of transmitted packets and dividing the value by the number of received bits as a bit error rate of the transmission path.

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