JP2014230160A - Network quality measurement system, method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the quality of a packet flowing over a large-scaled network while enlarging a measurement range, reducing cost of measurement and improving measurement accuracy.SOLUTION: A routing device routes only an SYN packet which is transmitted to a destination that is not present in a network, to a packet gathering device, and the packet gathering device captures only the SYN packet routed from the routing device and gathers header information included in the SYN packet. A delay calculation device calculates a differential in a time of arrival between packets from time stamp information extracted from the header information and calculates fluctuation in one-way delay of the packet from a retransmission time-out time corresponding to OS information of the header information.

Description

  The present invention relates to a network quality measurement system, method, and program, and more particularly, to a network quality measurement system and method for estimating communication quality (one-way delay fluctuation, round-trip delay) for each user of a packet flowing on a large-scale network. And the program.

  Network quality measurement technology is broadly divided into passive measurement technology and active measurement technology.

The passive measurement technique is a technique in which a user's actual traffic is measured traffic (for example, see Non-Patent Document 1).
The active measurement technique is a technique for measuring network quality by transmitting a probe packet for quality measurement to a user terminal for measurement and measuring the delay time (for example, Patent Documents 1, 2, and 3, Patent Document 2).

JP 2012-182747 A Japanese Patent No. 4815534 Japanese Patent No. 4522164

IEICE Transactions January 2006 Nippon Telegraph and Telephone Corporation Reduces storage space and avoids measurement errors in the IP network passive delay variation measurement method using hash functions. Information Processing Society of Japan Workshop June 2002 IBM Japan Co., Ltd. Characteristics of packet arrival interval and loss rate on the Internet.

  In the passive measurement technique described above, the amount of traffic to be measured and the amount of users vary greatly depending on the installation position and the number of installations of the measurement apparatus. For example, when the measurement target traffic volume and user volume are increased, the communication quality of many users can be measured, but the traffic collection cost and traffic analysis cost increase. In this way, when measuring communication quality with passive measurement, it is necessary to increase the number of traffic collection points in order to analyze the traffic of many links, users, and paths. There is a trade-off relationship. In addition, since only user traffic passing through the measuring device can be measured, there is a problem that a measurable range is narrow.

  The above active measurement technique can measure only the network quality of the probe packet passing path. On the other hand, in order to measure the quality of many passing paths, it is necessary to change the position of the measurement terminal in the network and implement the quality measurement, which requires measurement costs. In addition, since the test traffic and user traffic have different characteristics, the communication quality cannot be measured accurately. Furthermore, it is necessary to throw a plurality of probe packets in order to increase the measurement accuracy, and there is a problem that a measurement load is imposed on the network.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a network quality measurement system, method, and program capable of performing network quality measurement with a large measurement range, low measurement cost, high measurement accuracy, and the like. To do.

In order to solve the above problems, according to one aspect, a quality measurement system for estimating communication quality for each user of a packet flowing on a large-scale network,
A user terminal is connected to a network including a plurality of routing devices, one packet collection device, and one delay calculation device,
The routing device
Means for routing only SYN packets sent to destinations not present in the network to the packet collection device;
The packet collection device includes:
Means for capturing only the SYN packet routed from the routing device and collecting header information included in the SYN packet;
The delay calculation device includes:
Inter-packet arrival time Xi obtained from the time stamp information extracted from the header information, retransmission timeout time RTO corresponding to the OS information of the header information, and one-way delay fluctuations from the one-way delay OWD from the user terminal A quality measurement system having means for determining ΔOWD is provided.

Furthermore, according to another aspect, there is provided a quality measurement system for estimating communication quality for each user of a packet flowing on a large-scale network,
A user terminal is connected to a network including a plurality of routing devices, one unreachable notification reply device, one packet collection device, and one delay calculation device,
The routing device
Means for routing only SYN packets sent to destinations not existing in the network to the unreachable notification reply device;
The unreachable notification reply device
Means for transmitting an RST packet for the SYN packet routed from the routing device to a source of the SYN packet;
The packet collection device includes:
Means for capturing only the SYN packet via the unreachable notification reply device, and collecting header information included in the SYN packet;
The delay calculation device includes:
A difference Xi of arrival times between packets is determined from the time stamp information extracted from the header information, and a time RDi from when the SYN packet is received from the unreachable notification reply device to when the RST packet is transmitted is determined. Based on the OS information of the header information, obtain the user terminal time TDi from when the RST packet is received until the SYN packet is transmitted, and add the upstream unidirectional delay and downstream unidirectional delay time to reduce the round trip delay. A quality measurement system having means for determining is provided.

  As described above, according to one aspect, only the SYN (Synchronize) packet to a destination where no real user exists in the network is routed to one place, so that the details for each user terminal with a large number of user terminal names from the network. Communication quality (one-way delay fluctuation, bidirectional delay, bidirectional delay fluctuation, etc.) can be measured at low cost (just by collecting packets at one location in the network).

  In addition, there are the following advantages compared with the active measurement used in the network quality measurement.

  ・ Communication quality of general user terminals, not measurement terminals, can be measured (measurement can be performed according to the actual environment).

  ・ There are many observation terminals.

  -Do not put a measurement load on the observation target terminal and network.

It is a system configuration figure in a 1st embodiment of the present invention. It is a flowchart of the process in the 1st Embodiment of this invention. It is a flowchart of the process of S120 in the 1st Embodiment of this invention. It is an example which captures the packet transmitted to the destination which does not exist in the 1st Embodiment of this invention. It is a system block diagram in the 2nd Embodiment of this invention. It is a flowchart of the process in the 2nd Embodiment of this invention. It is an example in which an RST packet is transmitted to a packet transmitted to a nonexistent destination in the second exemplary embodiment of the present invention.

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

  The present invention collects packets destined for non-existing destinations at a single location, thereby measuring a one-way delay jitter from the user to the network (first embodiment) and a method for measuring non-existing destinations. A packet collection is performed in an environment where there is a mechanism for notifying a packet unreachable notification, and a method (second embodiment) for measuring round trip delay time and round trip delay jitter is performed.

[First Embodiment]
FIG. 1 shows a system configuration according to the first embodiment of the present invention.

  The system shown in FIG. 1 includes a plurality of user terminals 2 connected to a network 1, and the network 1 includes a plurality of routing devices 10, a single packet collection device 20, and a single delay calculation device 30. Has been.

  Each routing device 10 routes a packet transmitted to a destination that does not exist in the network 1 to the packet collection device 20 in the network 1.

Packet collection unit 20, in the example of the figure, is connected to the routing device 10 _1, captures all packets sent to a destination that does not exist in the network transmitted from the routing device 10 ₁ (SYN packet) The collected packet information is recorded in a memory (not shown).

  The delay calculation device 30 reads and identifies the collected packet information recorded in the packet collection device 20, and calculates a one-way delay jitter.

  Below, the process in said structure is demonstrated.

  FIG. 2 is a flowchart of processing in the first embodiment of the present invention.

Step 100) Routing a packet to a non-existent destination in the routing device 10:
Each of the routing devices 10 ₁ to 10 ₃ routes a packet transmitted to a destination that does not exist in the network 1, and the routing device 10 ₁ routes to the packet collection device 20. In the case of TCP communication that occupies most of the traffic, only the SYN packet transmitted at the beginning of communication is routed to the packet collection device 20, so that the disk capacity required for the packet collection device 20 is smaller than that in the case of normal passive measurement. It's small.

Step 110) Packet collection in the packet collection device 20:
All packets transmitted to a non-existent destination arrive at the packet collection device 20, but here, SYN packets used in TCP (Transmission Control Protocol) communication are collected, and only SYN packets are captured. . The information to be collected is all header information included in the TCP SYN packet including time stamp information, source IP address, destination IP address, source port number, protocol number, and the like. These pieces of information are recorded in a memory (not shown) in the packet collection device 20 (step 120). Pre-processing in the delay calculation device 30:
FIG. 3 is a flowchart of the process of step 120 in the first embodiment of the present invention.

  Step 121) The delay calculation device 30 reads the collected packet information from the memory (not shown) of the packet collection device 20, and performs the following processing.

  Step 122) Disassembly processing for each source IP address: Disassemble the collected packet information into packets for each source IP address.

  Step 123) Decomposition processing by TCP session IP: Decomposes packets into packets by TCP session ID by source IP address.

  Step 124) OS identification processing: OS identification is performed on a packet by TCP session ID.

Step 130) One-way delay jitter calculation processing in the delay calculation device 30:
The delay calculation apparatus 30 performs the following process from the information obtained in the process of step 103.

(1) Arrival interval time X _i = T _{i + 1} −T, which is the difference between packet arrival times T _i and T _{i + 1} from the time stamp information of the packet information for each TCP session ID extracted in the process of step 124 above. _i is obtained and recorded in a memory (not shown).

(2) The TCP retransmission timeout time RTO _i is checked from the OS information identified in step 124.

(3) When the one-way delay from the user terminal 2 (One-Way-Delay) representing the OWD _i, relation between the OWD _i and X _i and RTO can be expressed as equation (1) (see FIG. 4 ).

X = RTO _i −OWD _i + OWD _{i + 1} formula (1)
(4) Jitter is obtained from the above equation (1).

Assuming ΔOWD _{i + 1} −OWD _{i + 1} −OWD _i , equation (1) can be transformed into equation (2), and ΔOWDi can be obtained.

△ OWD _i = X _i −RTO _i (One-way delay fluctuation) Equation (2)
Here, ΔOWD _i is a one-way delay fluctuation (jitter) of the packet.

(5) By obtaining a plurality of ΔOWD _i , it is possible to measure network quality indicators such as average jedder value and maximum jitter value for each source IP.

  The jitter obtained as described above is output as a quality measurement result.

  As described above, in this embodiment, the communication quality is measured only from the packet arrival interval information by using the fact that the retransmission behavior by OS when transmitting a packet to a non-existing destination in TCP communication is known in advance. ing.

[Second Embodiment]
This embodiment is based on a TCP resetter that solves the IPv6 / IPv4 fallback problem described in Patent Document 4 (Japanese Patent No. 4447651). This technology reduces a wasteful waiting time when a node capable of communicating by IPv4 and IPv6 establishes communication with a server in which both an IPv4 address and an IPv6 address are registered.

  FIG. 5 shows a system configuration in the second embodiment of the present invention.

  In the figure, the same components as those in FIG.

  In the system shown in FIG. 1, a packet response device 40 that is an unreachable notification return mechanism is added to the system shown in FIG. 1, and the packet response device 40 is connected to the routing device 10 and the packet collection device 20. Different from the system configuration of FIG.

In the first embodiment, it had captured the routed packets from the routing device 10 ₁ in the packet collection unit 20, in the present embodiment, packet response unit 40 receives the SYN packet from the routing device 10 ₁ . When receiving the SYN packet, the packet response device 40 returns an RST packet to the user terminal 2. At this time, the delay calculation device 30 receives the SYN packet in the packet response device 40, returns the RST packet, and measures the time X from when the next SYN packet is received. Specifically, there are multiple IP networks, which are composed of IPv4 and IPv6 networks, and nodes that can communicate with IPv4 and IPv6 register both IPv4 addresses based on IPv4 and IPv6 addresses based on IPv6. For example, when a node first attempts to establish communication using IPv6, a TCP session establishment request packet using IPvc6 transmitted from the node is transmitted to the packet response device 40 installed in the IPv6 network. Received at. Then, the packet response device 40 refers to the destination address of the received TCP session establishment request packet, determines whether there is a connection route from the IPv6 network to the server specified by the destination address, and if there is no connection route, the RST packet Reply. The delay calculation device 30 measures this time.

  The operation of the above system is shown below.

  FIG. 6 is a flowchart of processing in the second embodiment of the present invention.

Step 200) In the routing devices 10 ₁ to 10 ₃ , only the packet transmitted to the destination that does not exist in the network 1 is routed, and the routing device 10 ₁ routes the SYN packet to the packet response device 40.

  Step 210) Upon receiving the SYN packet, the packet response device 40 sends the packet to the packet collection device 20, and sends the RST packet to the transmission source of the SYN packet. At this time, a time stamp is given to the received SYN packet and the RST packet returned to the transmission source of the SYN packet.

  Step 220) The packet collection device 20 captures a packet from the packet response device 40 as in step 110 of the first embodiment.

  Step 230) The delay calculation apparatus 30 performs pre-processing similar to that in the first embodiment.

  Step 240) The delay calculation apparatus 30 performs the following processing based on the information obtained in Step 230.

(1) The arrival interval time X _i = T, which is the difference between the packet arrival times T _i and T _{i + 1} , from the time stamp information of the packet information by TCP session ID obtained from all header information included in the TCP SYN packet _{i + 1} −T _i is recorded.

  (2) The delay calculation device 30 reads the packet collection data of the packet collection device 20, and measures the delay RDi from the reception of the SYN packet in the packet response device 40 to the transmission of the RST packet.

(3) The intra-terminal delay time TD _i in the user terminal 2 from the reception of the RST packet to the transmission of the SYN packet from the OS information identified by the pre-processing in step 230 is examined. It should be noted that TDi is set by the OS.

(4) If the upstream unidirectional delay is OWD _i _up and the downstream unidirectional delay is OWD _i _down, the relationship between X _i , RD _i , and TD _i can be expressed as in equation (3).

X _i = RD _i + TD _i + OWD _i _down + OWD _{i + 1} _up Equation (3)
(5) Here, round trip delay
RTT _i = OWD _i _up + OWD _{i + 1} _down
Then, the round-trip delay RTT _i is obtained by the equation (4).

_{RTT i = X i -RD i -} TD i ( round trip delay) (4)
The round trip delay jitter obtained as described above is output as a quality measurement result.

  As described above, in the present embodiment, since packets to destinations that do not exist in the network are collected and measured at one location of the packet response device 40, the packet collection device 20 and the delay calculation device 30 are collected at one location. It is only necessary to place it, and quality measurement can be performed at low cost. In addition, since only SYN packets are collected, both collection cost and analysis cost are low.

  Each process of the delay calculation device 30 shown in FIG. 1 and FIG. 5 can be constructed as a program and installed in a computer used as the delay calculation device to be executed or distributed via a network. It is.

  The present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the claims.

DESCRIPTION OF SYMBOLS 1 Network 2 User terminal 10 Routing apparatus 20 Packet collection apparatus 30 Delay calculation apparatus 40 Packet response apparatus

Claims (7)

A quality measurement system for estimating communication quality for each user of packets flowing on a large-scale network,
A user terminal is connected to a network including a plurality of routing devices, one packet collection device, and one delay calculation device,
The routing device
Means for routing only SYN packets sent to destinations not present in the network to the packet collection device;
The packet collection device includes:
Means for capturing only the SYN packet routed from the routing device and collecting header information included in the SYN packet;
The delay calculation device includes:
Inter-packet arrival time Xi obtained from the time stamp information extracted from the header information, retransmission timeout time RTO corresponding to the OS information of the header information, and one-way delay fluctuations from the one-way delay OWD from the user terminal A quality measurement system characterized by having means for obtaining OWD. A quality measurement system for estimating communication quality for each user of packets flowing on a large-scale network,
A user terminal is connected to a network including a plurality of routing devices, one unreachable notification reply device, one packet collection device, and one delay calculation device,
The routing device
Means for routing only SYN packets sent to destinations not existing in the network to the unreachable notification reply device;
The unreachable notification reply device
Means for transmitting an RST packet for the SYN packet routed from the routing device to a source of the SYN packet;
The packet collection device includes:
Means for capturing only the SYN packet via the unreachable notification reply device, and collecting header information included in the SYN packet;
The delay calculation device includes:
A difference Xi of arrival times between packets is determined from the time stamp information extracted from the header information, and a time RDi from when the SYN packet is received from the unreachable notification reply device to when the RST packet is transmitted is determined. Based on the OS information of the header information, obtain the user terminal time TDi from when the RST packet is received until the SYN packet is transmitted, and add the upstream unidirectional delay and downstream unidirectional delay time to reduce the round trip delay. A quality measurement system comprising means for obtaining. The delay calculation device includes:
The difference in arrival time between packets is X _i = T _{i + 1} −Ti, the retransmission timeout time RTOi, and the one-way delay OWDi from the user terminal,
X _i = RTO _i −OWD _i + OWD _{i + 1}
△ OWD _{i + 1} −OWD _{i + 1} −OWD _i and one-way delay fluctuation △ OWDi,
△ OWD _i = X _i −RTO _i
The quality measurement system according to claim 1, further comprising means for obtaining by: The quality estimation device includes:
Packet arrival interval time Xi, delay RD _i , delay TD _i , uplink one-way delay OWD _i _up, and downlink one-way delay OWD _i _down
X _i = Rd _i + TD _i + OWD _i _down + OWD _{i + 1} _up
Round trip delay
RTT _i = OWD _i _up + OWD _{i + 1} _down
_{RTT i = X i -RD i -} TD i
The quality measurement system according to claim 2, further comprising means for obtaining by: A quality estimation method for estimating communication quality for each user of a packet flowing on a large-scale network,
In a system in which a user terminal is connected to a network including a plurality of routing devices, one packet collection device, and one delay calculation device,
The routing device is
Route only SYN packets sent to destinations not present in the network to the packet collector;
The packet collection device comprises:
Capture only the SYN packet routed from the routing device, collect header information contained in the SYN packet,
The delay calculation device comprises:
Inter-packet arrival time Xi obtained from the time stamp information extracted from the header information, retransmission timeout time RTO corresponding to the OS information of the header information, and one-way delay fluctuations from the one-way delay OWD from the user terminal △ Quality estimation method characterized by obtaining OWD. There is a quality estimation method for estimating communication quality for each user of packets flowing on a large-scale network,
In a system in which a user terminal is connected to a network including a plurality of routing devices, one unreachable notification reply device, one packet collection device, and one delay calculation device,
The routing device is
Route only SYN packets sent to destinations that do not exist in the network to the unreachable notification reply device,
The unreachable notification reply device
Sending an RST packet for the SYN packet routed from the routing device to the source of the SYN packet;
The packet collection device comprises:
Capture only the SYN packet through the unreachable notification reply device, collect header information included in the SYN packet,
The delay calculation device comprises:
A difference Xi of arrival times between packets is determined from the time stamp information extracted from the header information, and a time RDi from when the SYN packet is received from the unreachable notification reply device to when the RST packet is transmitted is determined. Based on the OS information of the header information, obtain the user terminal time TDi from when the RST packet is received until the SYN packet is transmitted, and add the upstream unidirectional delay and downstream unidirectional delay time to reduce the round trip delay. A quality estimation method characterized by obtaining. Computer
The quality estimation program for functioning as a means of the delay calculation apparatus of the quality measurement system of any one of Claims 1 thru | or 4.

Images