JP2002152266A - Packet loss measurement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packet loss measurement system that measures a packet loss in conventional way, without the need for provision of a synchronization device or the like. SOLUTION: An analyzer of the packet loss measurement system has a means that collects a flow denoting unification of packets being components of traffic from a measurement device, a means that counts the flow from the start of measurement by each device, and a means that calculates a packet loss from flow information of the same count. This invention eliminates the need for synchronizing the two measurement devices which have been required for the measurement of the conventional packet loss systems.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measurement system for measuring packet loss of traffic flowing in a network constructed by a plurality of network devices.

[0002]

2. Description of the Related Art In a measurement system for measuring traffic generated when communication data is transferred between network devices, measurement information is collected from a plurality of network traffic measurement devices and generated on a network path from a correlation between the obtained information. There is a means to measure the state of traffic.

[0003] Regarding the collection of data measured from one measuring device, the IETF (The Internet Engineering Task Fo rm)
rce) RFC2063 "Traffic Flow Measurement: Architec
ture ”defines the measurement system configuration and measurement data. Also, RFC2720“ Traffic Flow Measurement: Me ”
The "ter MIB" defines management information for measurement called the Meter MIB. In the Meter MIB, various combinations such as a pair of a source and a destination and a pair of a source port and a destination port are used to transfer network traffic. It specifies management information that can collect the amount of traffic collected by the remote management device from the remote management device.This traffic is composed of a plurality of packets that store the data to be transferred. Meter MI
In B, the measurement information is summarized in this flow unit. If a packet under the same condition is not received for a certain period of time after measuring a certain packet, one flow is considered to have ended, and even if traffic under the same condition is measured, the flow is classified as a different flow. In these flows, the start time and the end time are also measured using the time of the apparatus.

Further, a method for analyzing packet loss from data obtained between two measurement devices is described in RFC2680 "
A One-way Packet Loss Metric for IPPM ”. In RFC2680, there are measurement devices at two points on the route for data transfer between certain network routes.
When measuring data on the transmitting side, it is determined that the packet is not lost if the data is received by an arbitrary time on the receiving side, and that the packet is lost if the data is received. For this reason,
When measuring the packet loss using information obtained from two measurement devices, it is necessary to synchronize the time on each device.

At present, GPS (Global Positioning System) and
Attempts are made to synchronize the time between devices using NTP (Network Time Protocol) or the like.

[0006] In addition to the above, there is a method of measuring packet loss in consideration of a specific application. For example, TCP
There is also a method of determining whether a packet has been received on the receiving side based on the IP sequence number of / IP.

[0007]

However, according to the above-mentioned method, a function for time synchronization is added to the network device, resulting in a large loss in cost. Further, in order to increase the reliability of the calculated packet loss, it is necessary to provide a highly accurate synchronization device because it depends on how accurately this time synchronization is performed.
Furthermore, how long the receiving side should measure the packet is one of the ways to increase the reliability of the packet loss value.
There is no way to explicitly determine this wait time.

Further, since data for various applications flows in the traffic flowing through the network, the packet loss measurement taking account of the specific application cannot always measure the packet loss of the traffic flowing in the network. .

In view of the above, an object of the present invention is to measure a packet loss for a general purpose without using a synchronizer or the like.

[0010] In order to achieve the above object, flow information from a plurality of measuring devices for measuring the flow is used. However, measuring packet loss using this information has the following problems. .

It is necessary to determine which flows and which flows have been obtained by the same traffic from the flow information obtained from the measuring device which is individually measured.

Regarding flow identification, a flow measured on the transmitting side may be measured as two flows on the receiving side due to delay or the like, and such a state must be identified.

Similarly, two flows measured on the transmitting side may be measured as two flows on the receiving side due to delay or the like.

[0014]

In order to solve the above-mentioned problems, in the case where the measuring device has a function of providing the above-mentioned Meter MIB, an analyzer for analyzing a packet loss uses this Me.
means for collecting flow information of the ter MIB, means for counting the flows collected for each condition from each device on each condition,
Means for comparing the number of packets of the same count number of flows under the same conditions,
It is characterized by measuring a loss.

Further, as another method, the measuring instrument has a function of holding the measured packet in addition to the function of providing the above-mentioned Meter MIB, and having a means of notifying the analyzer.
An analyzer for analyzing packet loss, in addition to the above means, has means for collecting traffic data from each device, and means for matching the collected traffic data from the start time of the flow, thereby ensuring the identity of the flows. It is characterized in that packet loss is calculated while guaranteeing.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

First, a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 shows an embodiment of a measurement system configuration to which a packet loss analysis method according to the present invention is applied.

Network terminals (40, 41, 42)
Are connected by a network composed of a plurality of network devices (30), and can exchange data with each other.

The measuring devices (200, 201) are distributed on a network and may be incorporated in a network device, or may measure network traffic between each device as a device different from the network device. There is also.

The analysis device (10) also manages configuration information from a network device and user information using the network for analyzing packet loss. The system according to the present embodiment includes a user terminal (40, 41, 4) using a network including a plurality of network devices.
2) It provides a measurement function that measures packet loss for a route between the two, and displays it to a management operator when a packet loss of an arbitrary value occurs. The management operator performs processing such as changing the user route or notifying the user based on the notified packet loss.

FIG. 2 shows an embodiment of each device configuration when the packet loss analysis system according to the present invention is applied to an analyzer that collects and analyzes measurement information from a measurement device.

A management communication network (1) is provided between the analyzer (10) and the measuring device (20), and is used for communication between the analyzing device and a plurality of measuring devices. The management communication network may be different from the communication network actually provided to the user, or the communication between the analyzer and the measurement device may be performed using the same network as the communication network.

The analysis device (10) includes a communication control device (11) for controlling communication for collecting measurement information from the measurement device (20), an operation area for program processing, and a work memory (12) for storing results. ), A database (13) for storing measurement information and analysis results collected from measurement devices on each network device, a measurement setting program (141) for setting measurement conditions for the measurement devices, and collecting and collecting measurement information from the measurement devices. A program memory (1) storing various measurement programs such as a packet loss analysis program (142) for calculating a packet loss based on information
4) A central processing unit (CP) that controls access to the program memory and database and execution of nuclear programs
U) (15), input devices such as a keyboard (16) and a mouse (17), a display device (CRT) (18), and an input / output control unit (19) for controlling input / output.

FIG. 3 shows the structure of network configuration information (300), measurement device information (310), and user information (320) stored in the database (13).

The configuration information (300) holds the connection relation of each network device, and each connection relation (30)
2,303) can be uniquely identified by the identifier (301).

The measuring device information (310) stores information (312) on a network area that can be measured for each measuring device (311). In the present embodiment, the measurable area is specified using the identifier (301) of the configuration information.

The user information (320) stores route information used by the user, and includes an identifier (3) for identifying the user.
21) in addition to the device address (322, 32) at the route end point.
3) and the connection relation information (324) constituting the 3). User information is added and deleted from the database (13) for each user who uses the network.

The measurement device (20) includes a communication control device 1 (21) for communicating with the analysis device (10) and a communication control device for collecting packets flowing through the measurement segment (2) which is a part of the communication network. Device 2 (22), packet capture program (23) for analyzing packets obtained from communication control device 2 (22), measurement for notifying data obtained by the capture program to the analysis device based on a request from the analysis device A program memory (25) including an information providing program (24), a work memory (26) for executing the processing of the program, and a central processing unit (CPU) (27) for controlling access to the memory and execution of each program. Is done.

Next, the operation of the measuring device in the operation of the present invention will be described.

FIG. 4 is a diagram showing traffic characteristics measured by the measuring device.

It is assumed that a packet flowing from the host A (41) to the host B (42) is being measured by the measuring device (200). The vertical direction in FIG. 4 represents the passage of time (401). The traffic flowing between the devices is generated by transferring a plurality of transfer packets (402) in a certain fixed time. RFC272
In the case of 0, this set of packets is flowed (403, 40
4).

The measuring device collects these packets,
By analyzing header information for packet transfer, the source, destination, protocol, port number, and the like of the packet are collected, and the number of packets and the data length are measured for each arbitrary combination. At this time, if a packet meeting the condition does not arrive for a certain period of time (flow boundary time (405)), the last measured packet is determined to be the end of the flow (403), and the same condition is satisfied thereafter. Even if a packet exists, it is measured as another flow (404).

When conforming to the RFC 2720 Meter MIB, the main measurement information relating to the flow includes the number of packets of the flow, the number of bytes of the flow, the start time of the flow (406),
The flow end time (407) and the like can be collected. Each measuring device measures the flow information and notifies the measurement information according to a request from the analyzing device.

Next, processing on the analyzer in the operation of the present invention will be described.

FIG. 5 is a flowchart relating to the processing operated by the measurement setting program (141) on the analyzer.

The processing of the measurement setting program is performed by
A threshold value for notifying an access point of a network route for collecting measurement information and a packet loss is received from a management operator monitoring loss (501). For example, the threshold value may be set to notify if the packet loss in a single measurement is equal to or more than a certain value, or may be set to be notified if the average packet loss per flow is equal to or more than a certain value. .

Next, based on the network configuration information (300) in the database, the connection relation between the network devices constituting the network path is identified. Then, based on the obtained connection relationship, a measurement device capable of measuring traffic at the end point of the route is identified from the measurable area (312) included in the measurement device information (310) (502).

Further, based on the information of the access point to the network route, based on the address of the data transmission source and the address of the data reception destination, "the data transmission source of the packet is the data transmission source address and the data reception destination Is measured for the packet which is the data receiving address. "(503).

Finally, for the processing of the packet loss analysis program, a source address, a destination address, and a notification condition of the packet loss are notified (504).

FIG. 6 is a flowchart relating to the processing operated by the packet loss analysis program (142) on the analyzer.

Packet loss analysis program (142)
First, when receiving a source address, a destination address, and a notification condition of a packet loss from the measurement setting program (141), it creates an analysis data table for storing data for analyzing the packet loss (60).
1).

FIG. 7 shows an embodiment of the analysis data table created by executing the packet loss analysis program.

The table ID of the analysis data table (70
1) is an identifier for uniquely identifying an analysis data table created for each measurement path.

In the analysis data table, based on the information received from the measurement condition setting program, the source address and the destination address which are the endpoints of the measurement path are respectively set to the transmission / reception address 1 (702) and the transmission / reception address 2 (703). Store. Also, what is the collected data collected from the measuring device is stored in the collected data (704). In the present embodiment, since it is necessary to collect each packet of the flow in order to calculate the packet loss, the collected information is “the number of packets”. Measurement points (70
5) stores the identifier of the measuring device that measures the traffic situation at the end point of the user route. Also, a condition for determining whether to notify the management operator is stored in the notification condition (706).

The above data is data stored when the analysis data table is generated.

The analysis data table has an area (707) for storing the final measurement time. The final measurement time represents the final time at which the analysis device has collected the flow data, and is determined based on the time on each measurement device. This value is collected at the same time that the packet loss analysis program collects the measurement data. For this reason, the final measurement time is changed each time measurement data is collected.

The analysis data table also generates a measurement information storage area (710) for storing data collected from the measurement device and the number of packet losses obtained from the measurement device.
Data is added to the measurement information storage area every time measurement is performed. As data to be stored, a counter (711) indicating the number of flows, each measuring device (71)
4) consists of the collected data (712) and the packet loss (713) calculated from the collected data.
Since the collected data of this embodiment is “number of packets”,
The number of packets acquired from each measuring device is stored (715).

After the packet loss analysis program creates the analysis data table, it collects data on all the flows having the same two transmission / reception addresses for the measurement points of the created table, in this embodiment, the number of packets. , Are collected (602). At this time, if the number of flows newly increases, the measurement information storage area of the analysis flow data table is extended by one, and the number of collected packets is stored in that area. At this time, the value of the counter (711) stores the value obtained by increasing the counter value of the previous flow data by 1 (60).
3).

This is performed for the designated measuring device.
At this time, if new flow data is obtained or the number of packets is the same as the number of packets of the previous measurement information obtained from the measurement device, it is assumed that one flow has ended.

The packet loss number is calculated by calculating the difference between the number of packets having the same counter value with respect to the data for which the flow has been determined to be completed (60).
4). The calculated packet loss number is stored in the packet loss (715) in the analysis flow data table (605).

Further, based on the stored packet loss number and the notification condition (706), it is determined whether or not to notify the management operator, and if the condition is satisfied, the management operator is notified of the packet loss (606). Regarding the analysis data table of FIG. 7, the notification condition is that the packet loss number is 1
If it exceeds 0, it will notify the management operator,
In the processing of the analysis processing program, the number of packet losses is notified to the management operator for the packet loss when the counter value is 2 from the measurement result.

The packet loss analysis program repeats the packet loss process until a measurement end command is received from the management operator (607).

By performing the above processing, the number of packet losses can be calculated for an arbitrary user route on the analysis device, and the management operator can be notified according to the result.

With the above configuration, it is possible to calculate the packet loss without having to synchronize the time between the measuring devices.

Next, as a second embodiment, a method for improving the reliability of the value of the packet loss by collecting, by the packet loss analysis program, the start and end times of the flow in addition to the number of packets of the flow. Will be described with reference to FIGS. 1 and 8 to 10.

The configuration of the measurement system based on this embodiment is as follows.
This is the same as the first embodiment.

In this embodiment, the processes of the packet capture program (23) and the measurement information providing program (24) on the measuring device (20) are the same. The same applies to the processing of the measurement setting program (141) on the analyzer.

FIG. 8 is a flowchart showing the processing of the packet loss analysis program (142) on the analyzer in this embodiment.

As in the first embodiment, the packet loss analysis program creates an analysis data table based on information obtained from the measurement setting program.

FIG. 9 is a diagram showing one embodiment of the analysis data table generated by the packet loss analysis program in this embodiment. The difference from the analysis data table generated in the first embodiment is that the collected data (704) is the start / end time of the flow in addition to the number of packets of the flow. In accordance with this, the measurement information storage area (7
The collected data (712) from the measurement device of (10) is also added to the number of packets of the flow (715) and the flow start time (90).
1), the flow end time (902) is stored for each measuring device.

The packet loss analysis program (142) based on the present embodiment converts the collected data into a measurement device (2).
0), when new flow data can be collected, the flow information is stored in the analysis flow data table.

Next, the packet
Calculate the loss. At this time, it is determined whether the calculated packet loss is not a proper value but a very large value (801). As a result, when the values are significantly different, the flow obtained by one of the measuring devices is 2
Judgment that it was measured as one or more flows,
A loss correction process is performed (802).

As a method of judging that the number of packet losses is extremely large, there is a method in which an average value of the packet losses up to that time is obtained, and when the average value deviates more than that value, it is judged that the packet loss is extremely large. When the number of packet losses is larger than a predetermined number of packet losses, it may be determined that the number is extremely large.

FIG. 10 is a flowchart of the packet loss correction processing.

First, it is determined whether the calculated packet loss number has a positive value or a negative value (100
1).

When the number of packet losses is a positive value, the packet loss analysis program transmits the flow from the receiving side to determine the possibility that one flow has been recognized as two flows by the measuring device on the receiving side. The start time of the next flow on the receiving side and the receiving side is collected (1002).

At this time, if the next flow does not exist on the transmission side, the flow on the reception side determines that the previous flow on the transmission side has become two flows at the measurement point on the reception side, and the next flow on the reception side is determined. Wait for the flow measurement to end (1003, 100
4).

In this case, when the information on the measurement flow on the receiving side is stored in the analysis flow data, the counter value is represented by a decimal point. For example, if the counter value of the previous flow is 5 and the above condition is satisfied, the measured counter value of the flow on the receiving side is 5.1.

If the next flow has been measured on the transmitting side, the start times of the flows on the transmitting side and the receiving side are compared (1005).

In comparing the times, the time error between the two devices is determined based on the start and end times of the collection flow so far.
For example, in the information on the flow of the counter 1, if the measured value of the start time on the transmitting side is 10000 and the measured value of the start time on the receiving side is 10100, it is determined that the transmitting / receiving side has a time error of about 100. . When comparing two flows based on this, the start time of the flow data on the sending side is 15000,
If the start time of the flow on the receiving side is 15050, the actual value is 14950 based on 15000 on the receiving side, and the start time is earlier than the transmission time of the flow, so this is determined as the previous flow be able to.

When calculating the packet loss, the packet loss is calculated by using the total number of packets in the measurement flow recognized as the same flow (1006).

On the other hand, when the number of packets on the transmitting side is larger than the number of packets on the receiving side, it can be considered that two or more flows measured on the transmitting side have become one flow on the receiving side. In this case, the number of packets of the next flow is added to the number of packets of the flow on the receiving side in the flow information on the transmitting side (1007).

Next, it is determined again whether the calculated packet loss number becomes a positive value or a negative value (1008). When the value becomes negative, the packet loss is calculated by adjusting the flow on the receiving side until the value becomes larger or equal.

The packet loss analysis program again determines whether the number of packet losses is significantly different from the value corrected by the above processing (1009).

The above is the packet loss correction processing.

After calculating the packet loss, the packet loss analysis program notifies the management operator of the packet loss information by the same processing as in the first embodiment.

By performing the above processing, it is possible to measure the packet loss even if the flow on the transmitting side is measured as two flows on the receiving side.

Next, as a third embodiment, a method of measuring a packet loss while identifying a flow by holding a copy of a packet measured by a measuring device and transferring collected data to an analyzing device will be described with reference to FIGS. 14 will be described.

FIG. 11 shows the configuration of this embodiment. This system has a configuration similar to that of the first embodiment, except that a packet copy program is added in the program memory (1101) on the measuring device.

Hereinafter, the processing of the measurement system based on this embodiment will be described.

First, the operation of the measuring device (20) according to the present invention will be described.

As in the first embodiment, the packet capture program (24) on the measuring device starts measurement based on the measurement conditions. When the packet capture program captures a packet, the packet capture program transfers the captured packet to a capture copy program. At this time, a capture time (hereinafter, capture time) is also notified. Further, when it is determined that the flow is new, a flow identifier for the new flow is also notified.

FIG. 12 shows a packet copy program (110
1) shows an outline of the processing to be performed.

The packet copy program collects packets from the packet capture program. Upon receiving the new flow identifier, the packet copy program creates a packet storage area (1201, 1202).

FIG. 13 shows an embodiment of the packet storage area.

The packet storage area stores a flow identifier (1301) for identifying a flow, a flow start packet storage area (1302) in which a packet at an arbitrary time from the start of the flow can be stored, and a packet at an arbitrary time before the end of the flow. Possible flow end packet storage area (1303)
There is. Each area has a structure in which a capture time (1304) for capturing a packet and a captured packet (1305) can be stored. In the example of FIG. 12, it is an area in which 10 packets of a flow start and a flow end can be stored.

The packet copying program stores the packet and the capture time obtained from the packet capture program in the packet storage area in order from the flow start area, and stores the packet and the capture time in the flow end packet area after the flow start packet area is full. The data is sequentially stored, and thereafter, the flow end packet area is overwritten.

For this reason, it is first determined whether or not the position where the capture information is stored is the end of the end packet storage area (1203).

If the storage position is at the end of the flow end area, the next packet can be overwritten on the oldest data in the flow end area. In this embodiment, since the flow end area is stored in order from the upper area, the packet copy processing program sets the storage position at the beginning of the flow end packet storage position (1204) and stores the captured packet information (1204). 1205).

The measurement information providing program (26) not only provides measurement information to the analyzer as in the first and second embodiments, but also converts data in the packet capture area as capture data for each flow. Can be provided to

The above process is a process performed on the measuring device.

Next, an outline of the processing on the analyzer according to the present embodiment will be described.

The processing of the measurement setting program (141) is the same as in the first embodiment.

FIG. 14 shows an outline of the processing of the packet loss analysis program (142) based on this embodiment.

The packet loss analysis program is based on
As in the second embodiment, when a request from the measurement setting program is received, an analysis data table is created.

Next, the packet loss analysis program measures the measurement information from the target device. At this time, the packet loss analysis program collects capture data for the corresponding flow (1401).

Regarding the method of collecting capture data,
In addition to collecting the measurement information, the measurement information providing program on the measurement device executes the process that it sends when the capture area on the measurement device is full, and the packet loss analysis program receives the data. There is also means for collecting packet capture data for each flow by holding the packet capture data.

After collecting the flow information, the packet loss analysis program performs packet matching on the captured data of the corresponding flow (1402).

For the packet matching at this time,
If the start of the flow and the end of the flow are matched, it is determined that the flows are the same (1403).

If the flow is the same, the packet loss is calculated based on the information obtained from the measuring device (140).
5).

If the start flow can be matched and the end flow cannot be matched, the receiving side collects the flows on the receiving side until it is recognized as two or more flows, and collects the flows until the collected flows can be matched. The packet loss is calculated using the data up to the point (1404, 1405).

The processing after calculating the packet loss is the same as in the first and second embodiments.

By performing the above processing, packet loss information is generated on the analyzer.

With the above configuration, the packet loss can be measured without time synchronization on each measuring device, and the reliability of the calculated value of the packet loss can be improved by the packet matching. .

[0106]

According to the present invention, if there is a means for measuring a flow on a measuring device and providing the same to an analyzing device, a time synchronization for measuring the packet loss and a time synchronizing each measuring device. Packet loss in actual network traffic can be measured without inserting a device.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a network configuration using a packet loss measurement system according to the present invention.

FIG. 2 is a diagram illustrating a system configuration of a packet loss measurement system according to first and second embodiments of the present invention.

FIG. 3 is a diagram showing a group of information stored in a database used in the first embodiment of the present invention.

FIG. 4 is a diagram showing network traffic measured in the present invention.

FIG. 5 is a schematic flowchart of a measurement setting program existing on the analyzer according to the first embodiment of the present invention.

FIG. 6 is a flowchart showing an overall processing outline of a packet loss analysis program existing on the analysis device of the first embodiment of the present invention.

FIG. 7 is a diagram illustrating an embodiment of an analysis data table used by a packet loss analysis program existing on the analysis device according to the first embodiment of the present invention.

FIG. 8 is a flowchart showing an outline of the overall processing of a packet loss analysis program existing on the analyzer according to the second embodiment of the present invention.

FIG. 9 is a diagram illustrating an embodiment of an analysis data table used by a packet loss analysis program existing on the analysis device according to the second embodiment of the present invention.

FIG. 10 is a schematic flowchart of a packet loss correction process of a packet loss analysis program existing on the analysis layer according to the second embodiment of the present invention.

FIG. 11 is a diagram illustrating a system configuration of a packet loss measurement system according to a third embodiment of the present invention.

FIG. 12 is a diagram showing an outline of the overall processing of a packet copy program existing on a measuring device according to a third embodiment of the present invention.

FIG. 13 is a diagram illustrating an embodiment of a flow packet storage area used by a packet copy program existing on a measuring device according to a third embodiment of the present invention.

FIG. 14 is a flowchart showing an outline of the overall processing of a packet loss analysis program existing on an analyzer according to a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Management communication network, 2 ... Measurement segment, 10 ... Analysis device, 11 ... Communication control device on analysis device, 12 ... Work memory on analysis device, 13 ... Database, 14 ... Program memory on analysis device, 15 ... Central processing unit on analysis device, 16 ... Keyboard, 17 ... Mouse, 18 ... Display, 19 ... Input / output device, 20 ... Measurement device, 21 ... Management communication device on measurement device, 22 ... Capture on measurement device Communication device for use, 25: Program memory on measurement device, 26: Work memory on measurement device, 27: Central processing device on measurement device, 30: Communication device, 40: Network terminal

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Minoru Koizumi 1099 Ozenji Temple, Aso-ku, Kawasaki City, Kanagawa Prefecture F-term in Hitachi, Ltd. System Development Laboratory 5K030 GA11 HA08 HB06 HB08 KA01 KA03 KA07 KA13 MB09 MC07 MC09 MD07

Claims (7)

[Claims] 1. A measuring device comprising: a measuring device for measuring a packet constituting a network traffic; and an analyzing device for collecting and analyzing measurement information from the measuring device.
The packets to be measured are classified based on conditions such as a source and a destination (hereinafter referred to as measurement conditions). If a packet meeting the conditions is not measured for a certain period of time, the measurement information up to that time is defined as one flow, In a measurement system having a unit for measuring the traffic as a flow different from the traffic even if the packet is measured over time, the analysis device may determine the number of packets measured under the same measurement conditions from a plurality of measurement devices. Has a means for collecting the information on the above flows and counting the number of flows measured for each measurement condition, and calculating the packet loss for each measurement condition by comparing the number of packets in the flow with the same count number A measurement system characterized by having a means for performing. 2. The measuring system according to claim 1, wherein the measuring device has means for transferring the traffic data itself measured at the same time as the flow information, and the analyzing device has the traffic data collected when calculating the packet loss. A measurement system characterized by having means for guaranteeing the identity of flows collected between two points by matching each other. 3. The measurement system according to claim 1, wherein the analyzer has means for collecting the start and end times of the flow at the same time as the number of packets, and the analyzer has a clear difference in the number of packets in the flow matching. At one time, the start time of the subsequent flow is compared with the end time of the flow, and the number of packets of two or more flows obtained from the measuring device on the receiving side of the flow and the number of packets obtained from the measuring device from the transmitting side of the flow are obtained. A measurement system comprising means for calculating the number of packet losses from the number of packets of a flow. 4. The measurement system according to claim 2, wherein the traffic data transferred by the measurement device includes a unit for transferring a part of data in the flow. 5. The measurement system according to claim 3, wherein the measurement device collects the traffic data after the start of the flow and immediately before the end of the flow, as the partial traffic data. 6. A measuring device for measuring packets constituting network traffic, and an analyzer for collecting and analyzing measurement information from the measuring device, wherein the measuring device comprises:
If the packet is classified based on the measurement condition and the packet matching the condition is not measured for a certain period of time, the measurement information up to that time is defined as one flow, and even if the packet is measured for more than the certain period, the traffic is In a measurement system having means for measuring as a flow different from traffic, the analysis device may include a request from a requester such as a management operator or a management application for notifying a packet loss in an arbitrary path of a managed network. A means for receiving, and a means for designating a condition for measuring traffic related to the path to a measuring apparatus on a path designated to collect packet loss, to the measuring apparatus, wherein the measuring apparatus receives the designation from the measuring apparatus. By collecting the flow information for each condition and counting for each flow, the same Measurement system characterized by having a means for providing a flow comprises means for calculating the number of packets than the number of the difference packets of information, the result with respect to their request management operator and management application. 7. The measurement system according to claim 6, wherein the analyzer has means for receiving a condition for notification together with the measurement condition, and a packet loss satisfying the condition based on a packet loss result for each flow. A means for notifying a management operator or a management application of the measurement system.