JP2007049602A - Network quality evaluation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a network quality evaluation apparatus capable of performing low-cost and high-reliability network quality evaluation. <P>SOLUTION: In a network quality evaluation apparatus, probes are installed on a network to be measured, and a first probe P1 includes a test packet generating means for generating a test packet including, in a payload, a sequence number indicating a packet generation order in one probe and an extraction means for extracting required data from a predetermined packet being passed and for writing the extracted data into a memory. A second probe P2 includes a test packet response means for writing reception time information, processing time information and a sequence number indicating a packet generation order in the second probe P2 into a payload of a test packet when the test packet outputted from the first probe is received, and redirecting the test packet to the first probe. Based on the data extracted and written in the memory by the first probe P1, communication quality of the network to connect these terminals is evaluated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a network quality evaluation apparatus, and more particularly to an improvement in an apparatus that extracts and captures communication packets propagating on a communication network and evaluates the communication quality of the communication network based on the information.

The Internet is widespread as a familiar communication network. However, in such a communication network, if the communication quality for the service you want to use is not sufficiently satisfied, communication abnormalities such as packet data loss and delay time fluctuations may occur. May occur.
When such a communication abnormality failure occurs, for example, in the case of a voice information service, the received voice may be interrupted, or in the case of a video information service, the movement of the received video may become unnatural.

  In addition, since the intermediate path of a communication network is shared by a plurality of terminals and services on the Internet, communication quality may deteriorate when the number of users accessing simultaneously increases compared to the case where the number of users is small. Furthermore, there is a case where the branch line portion is overloaded in the lines constituting the communication network.

  Therefore, in order to evaluate the communication quality of these communication network lines, monitor traffic, etc., network quality that evaluates the communication quality of the communication network based on the information extracted by extracting and capturing the communication packets propagating on the communication network. An evaluation device is used.

JP 2003-101583 A Japanese Patent Laid-Open No. 2001-127795

  Japanese Patent Laid-Open No. 2004-228561 performs communication between a capturing unit that captures a communication packet and outputs the information together with a time stamp, a ring memory that stores information for a certain period, and a probe manager connected to a communication network. Controls the circuit and the entire device, and in the normal state, the information stored in the ring memory is thinned out and read out and transmitted to the probe manager, and when there is a detailed read request from the probe manager, it is stored in the ring memory. There is described a network quality evaluation apparatus capable of reducing the amount of information of communication between a probe and a probe manager by providing a control circuit that reads information as it is and transmits it to the probe manager.

  In Patent Document 2, packet data is extracted from a plurality of locations in a communication network, and a network quality evaluation apparatus that evaluates the communication quality of the network based on the extracted data communicates with the communication network using detection of deterioration in communication quality as a trigger. There is described a network quality evaluation apparatus that can accurately specify the occurrence location when deterioration of communication quality is clarified by transmitting test packet data for quality measurement.

  FIG. 5 is a block diagram showing an example of a conventional network quality evaluation apparatus. In FIG. 5, ISP (Internet Service Provider) networks 1 and 2 are communication networks provided by providers. The plurality of corporate networks 3 to 6 and the old telephone network 7 are connected to each other via the ISP networks 1 and 2 and the router R.

  In addition, a server 8 and a probe manager 9 are connected to the ISP network 1. The server 8 distributes video, web, mail, news and the like. Probes 10 and 11 having a function of extracting packet data from the communication network are connected to the probe manager 9.

  The probe 10 is provided so as to extract packet data flowing in the path connecting the corporate network (head office) 3 and the ISP network 1, and the probe 11 is packet data flowing in the path connecting the ISP network 1 and the corporate network (branch office) 6. Is provided to extract.

  In such a configuration, the packet to be measured flows from the host 12 connected to the corporate network (head office) 3 to the host 13 connected to the corporate network (branch office) 6 via the ISP network 1. To do.

  The probe manager 9 includes specific packet information extracted by the probe 10 connected to the path of the corporate network (head office) 3 and the ISP network 1, and the probe connected to the path of the corporate network (branch office) 6 and the ISP network 1. The specific packet information extracted in step 11 is captured.

  Then, a packet pair is detected based on the captured packet information, packet data and time stamps are collated and calculated, and the presence or absence of packet loss between the corporate network (head office) 3 and the corporate network (branch office) 6; Measure network communication quality evaluation items such as delay time, delay time fluctuation, and throughput.

  FIG. 6 is a block diagram showing a specific example of a conventional probe. In FIG. 6, the router of the corporate network (head office) 3 on the path connecting the corporate network (head office) 3 and the ISP network 1 is connected to the input port of the physical layer circuit 21, and the router of the ISP network 1 is connected to the output port. .

  The physical layer circuit 21 receives a packet from the communication network, and the packet filter 22 selects only the designated packet. Then, only predetermined information designated in the data filter 23 is selected.

  The event inserter 24 writes the time stamp input from the local timer 25 into the communication packet input from the data filter 23 as necessary, and outputs the time stamp to the memory control circuit 26.

  The memory control circuit 26 controls writing / reading with respect to the memory 27, stores only captured designated data in the memory 27 together with a time stamp, and sends the data from the memory 27 to the external communication circuit 28.

For example, the packet filter 22
Protcol
Source Address
Destination Address
To select the specified packet.
Then, the data filter 23
Packet ID
Information and
Time Stamp
Is extracted and written to the memory 27.

  The external communication circuit 28 transmits data to the probe manager 9.

The probe manager 9 confirms the same packet pair based on the information from such a plurality of probes, and from the difference in the time stamp, as described above,
Packet loss Delay time / delay fluctuation is calculated.

  However, in the network quality evaluation apparatus as shown in FIG. 5, if the probe configured as shown in FIG. 6 is used as the probe, various measurements can be realized because the probe has a high function, but the cost becomes high. There is a problem that.

  The present invention pays attention to such a conventional problem, and its purpose is to appropriately combine a conventional high-performance probe with a low-cost probe whose function is relatively limited, An object of the present invention is to provide a network quality evaluation apparatus that can perform cost-effective and highly reliable network quality evaluation.

In order to achieve such a problem, the invention of claim 1
A probe is installed in the measured network,
The first probe has a test packet generating means for generating a test packet including a sequence number indicating a packet generation order in one probe in a payload, and an extracting means for extracting necessary data from a predetermined packet passing through and writing it into a memory Have
When the second probe receives the test packet output from the first probe, it has test packet response means for writing processing time information in the payload of the test packet and returning it to the first probe.
A network quality evaluation apparatus characterized by evaluating communication quality of a network connecting these terminals based on data extracted by a first probe and written in a memory.

The invention of claim 2 is the network quality evaluation apparatus according to claim 1,
The communication quality evaluation target item of the network is characterized in that it is at least one of one-way or round-trip delay, jitter, and packet loss.

The invention of claim 3 is the network quality evaluation apparatus according to claim 1,
The probe has a time synchronization function,
The second probe has a test packet response function that writes reception time information and a sequence number indicating a packet generation order in the second probe to the payload and returns the same to the first probe.

The invention of claim 4 is the network quality evaluation apparatus according to claim 1,
The network has a plurality of transmission paths.

The invention of claim 5 is the network quality evaluation apparatus according to claim 1,
A hub is connected between the test packet generating means and the extracting means in the first probe.

The invention of claim 6 is the network quality evaluation apparatus according to any one of claims 1 to 5,
Means is provided for displaying a communication quality evaluation result of at least one of the networks.

  Accordingly, it is possible to realize a network quality evaluation apparatus that can perform network quality evaluation with low cost and high reliability.

  The network quality evaluation apparatus of the present invention will be described below with reference to FIG. FIG. 1 is a configuration diagram showing an embodiment of the present invention, and two types of probes P1 and P2 having different configurations are used for quality evaluation of the network NW to be measured. Specifically, when measuring the network quality between the head office and the branch office, the first probe P1 is arranged at the main office, which is a main base, and the second probe P2 is arranged at a branch office, which is a general base. .

  FIG. 2 is a configuration diagram showing a specific example of the first probe P1, and the same reference numerals are given to the portions common to FIG. The difference from the probe of FIG. 6 is that the probe P1 of FIG. 2 is provided with a test packet generation circuit 29 in addition to the configuration of FIG.

  FIG. 3 is a configuration diagram showing a specific example of the second probe P2. 6 differs from the probe of FIG. 6 in that the functional block other than the local timer 31 and the external communication circuit block 32 is removed and a test packet response circuit 30 is newly provided. Since the second probe P2 has a simplified block configuration and a limited function, the cost can be significantly reduced as compared with the first probe P1. Note that the second probe P2 can be substantially realized by software.

The measurement operation of FIG. 1 will be described.
The probes P1 and P2 perform time synchronization by accessing a known ntp server (not shown).

  The probe P1 has a communication port PT1 that transmits and receives a test packet and two measurement ports PT2 and PT3 that allow the packet to pass through. By sending a test packet from the communication port PT1, it passes through the measurement ports PT2 and PT3 and then flows to the network NW to be measured.

  Here, when the test packet is transmitted, the payload number of the test packet includes a sequence number SeqNumTX indicating the generation order from the probe P1.

At the measurement port of the probe P1, for example,
Protocol in the IP layer: Protcol
Source IP address in the IP layer: Source Address
Destination IP address in the IP layer: Destination Address
To select and capture the packet, and within that packet,
Packet ID in the IP layer: Packet ID
Sequence number in the payload: SeqNumTX
Information and capture time stamp: Time Stamp1
Is written into the memory 27 of the probe P1.

  The test packet transmitted from the communication port PT1 of the probe P1 is received by the communication port PT1 of the probe P2 after passing through the measurement target network NW.

The probe P2 returns it to the probe P1 immediately after capturing the test packet. At this time, in the probe P2, in the payload of the test packet,
Test packet reception time stamp: TimeRcv
Sequence number indicating the generation order from probe P2: SeqNumRX
Time stamp indicating processing time in the probe P2: ΔT
Is added.

  The test packet returned from the probe P2 passes through the measurement target network NW, passes through the measurement ports PT3 and PT2 of the probe P1, and is received by the communication port PT1.

At the measurement port of the probe P1, for example,
Protocol in the IP layer: Protcol
Source IP address in the IP layer: Source Address
Destination IP address in the IP layer: Destination Address
Select a packet with, capture and within that packet
Packet ID in the IP layer: Packet ID
Sequence number in the payload: SeqNumTX
Sequence number in the payload: SeqNumRX
Time stamp in the payload: SeqNumTX
Time stamp in the payload: ΔT
Information and
Time stamp of capture time: Time Stamp2
Is written into the memory 27 of the probe P1.

Based on the data thus written in the memory 27 of the probe P1, the following is shown.
(1) Round-trip delay, jitter, and packet loss measurement
(2) One-way delay and jitter measurement
(3) Perform various measurements such as one-way packet loss measurement.

(1) Round-trip delay, jitter, and packet loss measurement
Based on Src / Dst IP Address, Protocol, PacketID, and SeqNumTx, packet pair on the sending side and responding side is detected.
Round trip delay time (= TimeStamp2-TimeStamp1-ΔT)
Is calculated.
In SeqNumTx, the packet loss is measured because there is a packet on the sending side and no packet on the response side.

(2) One-way delay and jitter measurement One-way delay time during transmission (= TimeRcv−TimeStamp1)
One-way delay time during response (= TimeStamp2-TimeRcv-ΔT)
Measure.

(3) One-way packet loss measurement Loss during transmission: Response packet loss is subtracted from round-trip packet loss Response loss: Loss measurement due to missing in SeqNumRes

  According to the network quality evaluation apparatus configured as shown in FIG. 1, round-trip delay, jitter, packet loss measurement, one-way packet loss measurement, and one-way delay and jitter measurement when time synchronization is possible. Can do.

  By configuring the probe P1 with hardware and configuring the probe P2 with software, the reciprocal measurement is dependent on hardware, so that the time accuracy can be ensured to be high.

  By placing the probe P1 at the main base and the probe P2 at the general base, the software of the software can be obtained with a relatively small number of relatively expensive hardware probes P1 in the measurement at a large number of star-type bases. Since many inexpensive probes P2 can be provided, a system can be constructed at low cost.

  Note that the conventional passive measurement between the probes P1 and the active measurement between the probes P1 and P2 may be performed simultaneously.

  Moreover, you may perform the passive measurement using the test packet of a communication port between probes P1.

  Further, measurement may be performed between the probes P1 in the same manner as between the probes P1 and P2.

  Further, the configuration of the probe P1 may be realized by software between the probes P2 and the measurement may be performed by the same method as that between the probe P1 and the probe P2.

  Further, by connecting the hub 33 between the communication port PT1 and the measurement port PT2 of the first probe P1 as shown in FIG. 4, a plurality of networks and personal computers can be connected. More diverse measurements can be performed by combining PCs.

  If necessary, by providing means for displaying the communication quality evaluation result of at least one of the networks, it is possible to select a network route that the user has determined to be appropriate based on these measurement results.

  Also, by providing a first probe and a second probe for each path of a network having a plurality of transmission paths, traffic distribution, presence / absence of packet loss, large delay time included in the communication quality evaluation items of the network It is also possible to measure at least one of delay time fluctuation and throughput.

  Then, for example, the probe manager 9 monitors the transition of the delay time in each path of the branch system, and when the delay time of one path shows an increasing tendency, the packet transfer ratio to each path is adjusted and averaged To control. As a result, it is possible to properly distribute the load in the entire network, avoid transmission failures due to load concentration, and improve the stability of the entire network.

  As described above, according to the present invention, it is possible to realize a network quality evaluation apparatus that can perform network quality evaluation with low cost and high reliability.

It is a block diagram which shows one Example of this invention. It is a block diagram which shows the specific example of the 1st probe P1. It is a block diagram which shows the specific example of the 2nd probe P2. It is a block diagram which shows the other example of a connection of the 1st probe P1. It is a block diagram which shows an example of the conventional network quality evaluation apparatus. It is a block diagram which shows an example of the conventional probe.

Explanation of symbols

P1 First probe P2 Second probe NW Network to be measured 29 Test packet generation circuit 30 Test packet response circuit 31 Local timer 32 External communication circuit block

Claims (6)

A probe is installed in the measured network,
The first probe has a test packet generating means for generating a test packet including a sequence number indicating a packet generation order in one probe in a payload, and an extracting means for extracting necessary data from a predetermined packet passing through and writing it into a memory Have
When the second probe receives the test packet output from the first probe, it has test packet response means for writing processing time information in the payload of the test packet and returning it to the first probe.
A network quality evaluation apparatus characterized by evaluating communication quality of a network connecting these terminals based on data extracted by a first probe and written in a memory.   The network quality evaluation apparatus according to claim 1, wherein the communication quality evaluation target item of the network is at least one of one-way or round-trip delay, jitter, and packet loss. The probe has a time synchronization function,
2. The second probe has a test packet response function for writing reception time information and a sequence number indicating a packet generation order in the second probe in a payload and returning the same to the first probe. The network quality evaluation apparatus described.   The network quality evaluation apparatus according to claim 1, wherein the network has a plurality of transmission paths.   2. The network quality evaluation apparatus according to claim 1, wherein a hub is connected between the test packet generating means and the extracting means in the first probe. 6. The network quality evaluation apparatus according to claim 1, further comprising means for displaying a communication quality evaluation result of at least one of the networks.

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