JP2006174156A - Network congestion scale determining method and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To grasp a congestion state in a network in network link units by performing management while grasping the route information of a network link, and reflecting information on quality measured from each user session on the grasped route information. <P>SOLUTION: A topology management means 3 estimates route information between end hosts 7a, 7b from topology information by using Dijkstra algorithm. A route measuring means 2a informs a congestion determination means 5 of information on the end hosts 7a, 7b and the route information. Each of quality measuring means 4a, 4b periodically measures quality at a network level or an application level, compares it with a threshold to evaluate the quality, and informs the determination means 5 of a quality measurement result. The determination means 5 holds the end host information, the route information, and the quality measurement results; compares a ratio of the number of abnormal sessions to the number of all sessions with a threshold; and determines the congestion of a link (between routers) in the network. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a network congestion judgment method and system for measuring the application quality or transport quality in an IP network, and managing the quality measurement result and topology information in combination, thereby grasping the congestion scale for each link. Is.

  With the recent trend toward broadband users, demand for rich content such as stream distribution, VoIP, and video conferencing is increasing. However, current Internet-connected users use services by connecting various terminals to a network environment. In addition, many users use so-called best-effort services that do not have a quality guarantee regarding communication bandwidth, communication delay, and the like. For this reason, when the user concentrates on a point where there is access, quality degradation such as packet loss occurs and the quality of the application is affected.

  Therefore, in order to maintain and improve real-time application quality for stream distribution, VoIP, video conferencing, etc., the user's reception quality is aggregated to determine the congestion level of the network. Studies on methods for implementing the quality control technology (for example, Patent Document 1, Non-Patent Documents 1 and 2) are in progress.

JP 2004-48565 A Masahiro Hirono, Yoshihiko Uematsu, “Examination of video distribution rate control method considering fairness and priority among users”, IEICE Tech. 1-4 Masanobu Hirono, Konomi Kamada, Yasuhiko Yoshimura, Yoshihiko Uematsu, “NW Congestion Scale Judgment Method Based on FEC Restoration State Distribution Analysis”, 2004, IEICE Communication Society, B-7-23

  However, the conventional method of consolidating received quality for congestion determination is studied by statically setting a network area that divides the network at an arbitrary point in association with the user to understand the network topology. Are not managed. For this reason, the conventional method can operate when the communication destination is fixed, such as stream distribution where the communication destination is a server, and the configuration is simple such as a star network, but the communication destination is changed. If the configuration is complicated in an unfixed state such as a video conference, the operation becomes difficult. Further, since the actual network topology is not grasped, congestion is not grasped for each link, and congestion is grasped in units divided into several areas set as network areas.

  The present invention has been made to solve the above-mentioned problems, and its purpose is to grasp the route information of the network link, and to reflect and manage the quality information measured from each user session in the grasped route information. Thus, the congestion state in the network is grasped for each network link.

  The present invention relates to a network congestion scale determination method and system used for communication between end hosts provided with route measurement means, quality measurement means, and congestion determination means, wherein the route measurement means measures passing link information of the session between end hosts. To the congestion determination means, the quality measurement means measures the communication quality of the network in the communication between end hosts and notifies the quality determination result to the congestion determination means, and the congestion determination means is notified from the route measurement means. The session passing link information and the quality determination result notified from the quality measuring means are held, the quality determination result is reflected in the passing link unit of the session, and the network congestion scale in the link unit is determined.

  In the present invention, the route measuring unit notifies the congestion determining unit of the passing link information of the session between end hosts measured based on the response information from each network node (communication device on the network) with respect to the route search. Features. The present invention further comprises topology management means, wherein the path measurement means measures passing link information of the session between end hosts based on the topology information collected by the topology management means and notifies the congestion judgment means. Features. In addition, the present invention is characterized in that the path measurement unit measures a communication path or performs a route search, and the topology management unit collects the topology information at the time of session disclosure or periodically.

  Further, according to the present invention, the quality measurement means may include at least one of a reception band, packet reception / packet retransmission / packet loss, delay, frame rate, buffer amount, and the like from an application operating in a network node or an end host, It is characterized in that the communication quality at the network level or application level is measured and compared with a threshold value to determine the quality in units of sessions.

  In addition, the present invention is characterized in that the congestion determining means determines the network congestion scale by comparing the total number of normal, abnormal and abnormal sessions in units of network links with at least one threshold for these. Further, the present invention is characterized in that the congestion determination means receives a congestion inquiry request and responds with a determination result of the network congestion scale.

  According to the present invention, it is possible to grasp a congestion point for each link in a network and grasp a congestion scale. In addition, by combining with other quality control methods such as accommodation restriction and bypass control, the network can detect the congestion status on a link basis before the end host quality is affected, and use it as a trigger for other control. Quality stabilization can be realized.

  Hereinafter, embodiments of the present invention will be described in detail based on preferred examples shown in the drawings. In the following description, the OSPF (Open Shortest Path First) protocol is used as a method for collecting topology information from network nodes, and the SPF (Shortest Path Find) algorithm is used as a method for grasping the path between end hosts. Of course, the present invention is not limited to this. Other network topology information collecting means and route grasping means are within the scope of the present invention.

  FIG. 1 is a schematic configuration diagram of a network congestion scale determination system for explaining a first embodiment of the present invention. This network congestion scale determination system includes end hosts 7 a and 7 b, a network management server 8, and a network 6. The end hosts 7a and 7b measure communication application means (applications) 1a and 1b for executing predetermined processing, quality measuring means 4a and 4b for measuring the quality of the network 6, and communication paths between the end hosts 7a and 7b. Route measuring means 2a and 2b are provided. The network management server 8 includes topology management means 3 for managing topology information of the network 6 and congestion determination means 5 for determining congestion between links in the network 6. The end hosts 7a and 7b are connected to the network 6 via quality measuring means 4a and 4b installed in the same terminal or in an external terminal, and communicate between the end hosts.

  The topology management means 3 of the network management server 8 is connected to the network 6 and uses the OSPF protocol to transmit and receive LSA (Link-State Advertisement) to and from a Neighbor router (not shown), thereby linking the link state database. (Topology information) is created. 5 and 6 show examples of topology information managed by the topology management means 3 under the network configuration shown in FIG. In FIG. 4, Users 1 to 10 correspond to the end hosts shown in FIG. 1, RT 1 to 7 represent routers, N 1 to 7 represent networks, and the numbers attached to the left and right of RT 1 to 7 represent costs. FIG. 5 is a diagram of a network management table in the network configuration shown in FIG. This network management table has information on the network address, router ID, and cost from the router to the network. FIG. 6 is a diagram of a link management table in the network configuration shown in FIG. This link management table includes router IDs (Source and NextHop) and cost information from Source to NextHop. Here, the link (network link) refers to a communication path between adjacent routers in the communication path between the end hosts 7a and 7b. As described above, the topology management unit 3 manages the network management table and the link management table including the topology information illustrated in FIGS. 5 and 6.

  When the communication application means 1a in the end host 7a operates, a session between the communication applications 1a and 1b starts. Before this session starts, the route measuring unit 2a of the end host 7a notifies the topology management unit 3 of the network management server 8 of a route inquiry request with the IP addresses of the end hosts 7a and 7b. When the topology management means 3 receives the route inquiry request from the route measurement means 2a, the topology management means 3 uses the Dijkstra algorithm from the topology information of the network management table and link management table shown in FIGS. 5 and 6 to connect the end hosts 7a and 7b. The route is estimated, and the estimated route information is notified to the route measuring means 2a. When the route measuring unit 2a receives the route information from the topology managing unit 3, the route measuring unit 2a notifies the congestion determining unit 5 of the information of the end hosts 7a and 7b such as the IP address and the route information.

  After the session is started, the quality measuring means 4a, 4b of the end hosts 7a, 7b periodically receives at least one network of reception bandwidth, packet reception / packet retransmission / packet loss, delay, frame rate, buffer amount, etc. The quality at the level or the application level is measured, the measurement result is compared with a threshold value, the quality of the network 6 is evaluated, and the quality measurement result is notified to the congestion determination means 5. Here, the network level quality means the communication quality when the quality measuring means 4a and 4b are installed in an external terminal on the network 6 different from the end hosts 7a and 7b, and the application level quality means Communication quality when the quality measuring means 4a and 4b are provided in the same terminal as the end hosts 7a and 7b.

  When the congestion determination unit 5 receives the end host information and the route information from the route measurement unit 2a and the quality measurement result from the quality measurement unit 4a, the congestion determination unit 5 retains the information. FIG. 7 shows an example of a user management table held by the congestion determination means 5 in the network configuration shown in FIG. This user management table has a transmission source / destination user ID or IP address, route information, and a quality measurement result. Here, the transmission source / destination user ID or IP address corresponds to end host information. Referring to FIG. 7, for example, when the end hosts are User1 and User6, as the end host information, the transmission source user ID is “User1”, the transmission destination user ID is “User6”, and the path information is “RT1 → RT3 → RT6”. → RT5 => N4 "The quality measurement result is" NG ". The quality measurement result is also held as quality information in the link management table in addition to the user management table. FIG. 8 shows an example of a link management table held by the congestion determination unit 5. This link management table has a router ID, the total number of sessions, the number of normal sessions, the number of abnormal sessions, and an abnormal ratio. In FIG. 4, when the quality measurement result is abnormal (NG) in User 6, User 7, and User 8, the congestion determination means 5 determines the link management table from the quality measurement result (quality) and route information (Route) in the user management table. Update the number of sessions for the relevant link. Referring to FIG. 8, for example, when the routers are RT1 (Source) and RT3 (NextHop) (second line from the top), the route information on the first and third lines from the top of FIG. Since the first line is quality NG and the third line is quality OK, the total number of sessions is “2”, the number of normal sessions is “1”, the number of abnormal sessions is “1”, and the abnormality ratio is 50.

  Further, the congestion determination unit 5 periodically compares the ratio of the total number of sessions occupied by the number of abnormal sessions (abnormal ratio) with a threshold from the link management table to determine the congestion of the network link (between routers). In the present embodiment, when the congestion determination threshold is 80%, the links RT2 → RT3 and RT6 → RT5 are larger than the threshold 80% in the link management table shown in FIG. It is determined that However, when the number of samples is small (the number of samples is 1) as in link RT2 → RT3, the quality measurement result of one session greatly affects the congestion judgment, and therefore quality degradation occurs due to not network congestion. Even if there is, it is determined that there is congestion between the links in the network. Therefore, in addition to the threshold for the number of abnormal sessions, a threshold is set for the total number of sessions in the link, and only when the total number of sessions is equal to or greater than the threshold, the congestion determination is performed. In this embodiment, when the threshold for the total number of sessions is 2, only the link RT6 → RT5 is determined to be in the congestion state in the link management table shown in FIG.

  In addition, the congestion determination unit 5 can reply to a request from an external system, such as a congestion state for each link, whether an end-host path passes through a congested link, etc. It is possible to perform path detour control by notifying the link in a state, and session rate control and admission control when the end-host passing link is congested.

  FIG. 2 is a schematic configuration diagram of a network congestion scale determination system for explaining a second embodiment of the present invention. This network congestion scale determination system includes end hosts 7a and 7b, a network management server 8 and a network 6 as in the first embodiment. The end hosts 7a and 7b include communication application means 1a and 1b and quality measurement means 4a and 4b, respectively. The network management server 8 includes topology management means 3, path measurement means 2 c, and congestion determination means 5. The end hosts 7a and 7b are connected to the network 6 via quality measuring means 4a and 4b installed in the same terminal or in an external terminal, and communicate between the end hosts.

  The topology management means 3 of the network management server 8 is connected to the network 6 and uses the OSPF protocol to transmit and receive LSAs to and from the Neighbor router, so that a link state database comprising the network management table and the link management table shown in FIGS. (Topology information) is created. The function of the topology management unit 3 is the same as the function described in the first embodiment.

  When the communication application means 1a in the end host 7a operates, a session between the communication applications 1a and 1b starts. After the session is started, the quality measuring means 4a, 4b of the end hosts 7a, 7b periodically receives at least one network of reception bandwidth, packet reception / packet retransmission / packet loss, delay, frame rate, buffer amount, etc. The quality at the level or application level is measured, the measurement result is compared with a threshold value to evaluate the quality of the network 6, and the IP address of the end hosts 7a and 7b is assigned to the quality measurement result to thereby determine the congestion determination means 5 To notify.

  When the congestion determination unit 5 receives the quality measurement result and the IP address of the end host from the quality measurement units 4a and 4b, the congestion determination unit 5 sends a route inquiry request with the IP address of the end hosts 7a and 7b via the route measurement unit 2c. Output to the topology management means 3. When the topology management unit 3 inputs a route inquiry request from the route measurement unit 2c, the topology management unit 3 uses the Dijkstra algorithm from the topology information of the network management table and the link management table shown in FIGS. 5 and 6 to connect the end hosts 7a and 7b. The route is estimated, and the estimated route information is output to the congestion determination unit 5 via the route measurement unit 2c. In this case, the timing of the route inquiry request output from the congestion determination unit 5 to the topology management unit 3 is the time when the quality measurement result is received from the quality measurement units 4a and 4b or when the first quality measurement result of the session is received. (When there is no route information of the session in the user management table in FIG. 7).

  Further, when the route information is input from the route measuring unit 2c, the congestion determination unit 5 holds the quality measurement results and end host information received from the quality measuring units 4a and 4b, and the route information input from the route measuring unit 2c. 7 shows an example of a user management table held by the congestion determination means 5 in the network configuration shown in FIG. 4, and FIG. 8 shows an example of a link management table. That is, the congestion determination unit 5 holds these management tables as in the first embodiment. Further, when the quality measurement result is abnormal (NG), the congestion control unit 5 updates the number of sessions of the corresponding link in the link management table from the quality measurement result (quality) and the route information (Route) in the user management table. . Since the user management table in FIG. 7 and the link management table in FIG. 8 have already been described in the first embodiment, detailed description thereof is omitted here.

  Further, the congestion determination means 5 periodically compares the ratio of the total number of sessions occupied by the number of abnormal sessions (abnormal ratio) with a threshold from the link management table to determine the congestion of the link (between routers) in the network. . In the present embodiment, when the congestion determination threshold is 80%, as in the first embodiment, the links RT2 → RT3 and RT6 → RT5 are larger than the threshold 80% in the link management table shown in FIG. The link is determined to be congested. However, if the number of samples is small, such as link RT2 → RT3, it is determined that there is no congestion. That is, as in the first embodiment, a threshold is set for the total number of sessions in the link, and congestion determination is performed only when the total number of sessions is equal to or greater than the threshold.

  In addition, the congestion determination unit 5 can reply to a request from an external system, such as a congestion state for each link, whether an end-host path passes through a congested link, etc. It is possible to perform path detour control by notifying the link in a state, and session rate control and admission control when the end-host passing link is congested.

  FIG. 3 is a schematic configuration diagram of a network congestion scale determination system for explaining a third embodiment of the present invention. This network congestion scale determination system is composed of end hosts 7a and 7b, a network management server 8 and a network 6 as in the first and second embodiments. The end hosts 7a and 7b include communication application means 1a and 1b, path measurement means 2a and 2b, and quality measurement means 4a and 4b, respectively. The network management server 8 includes a congestion determination unit 5. The end hosts 7a and 7b are connected to the network 6 via quality measuring means 4a and 4b installed in the same terminal or in an external terminal, and communicate between the end hosts.

  When the communication application means 1a in the end host 7a operates, a session between the communication applications 1a and 1b starts. Before this session starts, the route measuring means 2a of the end host 7a performs a route search toward the end host 7b. Specifically, the route measuring means 2a measures a route such as a traceroute command and the like that increases the TTL (Time To Live) of the IP header from 1, while transmitting the IP packet to the target end host 7b. Route search is performed by using. The route measuring means 2a grasps the route between the end hosts by route search, and notifies the congestion judgment means 5 of the information of the end hosts 7a and 7b such as the IP address and the route information.

  After the session is started, the quality measuring means 4a, 4b of the end hosts 7a, 7b periodically receives at least one network of reception bandwidth, packet reception / packet retransmission / packet loss, delay, frame rate, buffer amount, etc. The quality at the level or the application level is measured, the measurement result is compared with a threshold value, the quality of the network 6 is evaluated, and the quality measurement result is notified to the congestion determination means 5.

  When the congestion determination unit 5 receives the end host information and the route information from the route measurement unit 2a and receives the quality measurement result from the quality measurement unit 4a, the congestion determination unit 5 retains the information. 7 shows an example of a user management table held by the congestion determination means 5 in the network configuration shown in FIG. 4, and FIG. 8 shows an example of a link management table. That is, the congestion determination unit 5 holds the user management table shown in FIG. 7 and the link management table shown in FIG. 8 as in the first and second embodiments. Further, when the quality measurement result is abnormal (NG), the congestion control unit 5 updates the number of sessions of the corresponding link in the link management table from the quality measurement result (quality) and the route information (Route) in the user management table. . Since the user management table in FIG. 7 and the link management table in FIG. 8 have already been described in the first embodiment, detailed description thereof is omitted here.

  Also, the congestion determination means 5 periodically compares the ratio of the number of abnormal sessions occupied by the number of abnormal sessions (abnormal ratio) with a threshold from the link management table to determine congestion between links in the network (between routers). To do. In this embodiment, when the congestion determination threshold is 80%, the links RT2 → RT3 and RT6 → RT5 are larger than the threshold 80% in the link management table shown in FIG. 8 as in the first and second embodiments. Therefore, it is determined that the link is congested. However, if the number of samples is small, such as link RT2 → RT3, it is determined that there is no congestion. That is, as in the first and second embodiments, a threshold is set for the total number of sessions in the link, and congestion determination is performed only when the total number of sessions is equal to or greater than the threshold.

  In addition, the congestion determination unit 5 can reply to a request from an external system, such as a congestion state for each link, whether an end-host path passes through a congested link, etc. It is possible to perform path detour control by notifying the link in a state, and session rate control and admission control when the end-host passing link is congested.

  As described above, in the third embodiment, unlike the first and second embodiments, it is not necessary to provide the topology management means 3 in the center system in which the network management server 8 is installed, and the load on the center system can be reduced.

  In the network congestion scale determination system described above, in the first and third embodiments, the path measuring means 2a, 2b and the quality measuring means 4a, 4b are arranged in the end hosts 7a, 7b. You may make it the structure with which each in another terminal. In the first embodiment, the topology management unit 3 and the congestion determination unit 5 are arranged in one network management server 8. However, the topology management unit 3 and the congestion determination unit 5 may be provided in different terminals. In the second embodiment, the topology management unit 3, the route measurement unit 2c, and the congestion determination unit 5 are arranged in one network management server 8. However, the topology management unit 3, the route measurement unit 2c, and the congestion determination unit 5 may be provided in different terminals. .

  In the network congestion scale determination system described above, in the first embodiment, before the session starts, the route measurement unit 2a notifies the route management unit 3 of the route inquiry request, and the topology management unit 3 estimates the route. I made it. In the second embodiment, when the quality measurement result after starting the session is received, the congestion determination unit 5 outputs a route inquiry request to the topology management unit 3 via the route measurement unit 2c, and the topology management unit 3 Was estimated. In the third embodiment, the route measuring unit 2a performs route search before the session starts. In this case, the timing at which the route measurement information 2a or the congestion determination unit 5 notifies the route inquiry request, the timing at which the topology management unit 3 estimates the route, and the timing at which the route measurement unit 2a performs route search are determined at the start of the session or It may be regular.

  Moreover, the quality measurement means 4a and 4b, the topology management means 3, the path measurement means 2a to 2c, and the congestion scale determination means 5 of the network congestion scale determination system shown in FIGS. Each is configured by a computer that incorporates. These software can be stored and distributed in a storage medium such as a magnetic disk (floppy disk, hard disk, etc.), optical disk (CD-ROM, DVD, etc.), semiconductor memory, etc. as a program that can be executed by a computer. .

It is a schematic block diagram of the network congestion scale determination system for demonstrating the 1st Example of this invention. It is a schematic block diagram of the network congestion scale determination system for demonstrating the 2nd Example of this invention. It is a system configuration | structure figure of the network congestion scale determination system for demonstrating the 3rd Example of this invention. It is a figure which shows the network structure for demonstrating topology information and quality information. It is a figure which shows the example of the network management table containing topology information. It is a figure which shows the example of the link management table containing topology information. It is a figure which shows the example of the user management table which a congestion determination means hold | maintains. It is a figure which shows the example of the link management table which a congestion determination means hold | maintains.

Explanation of symbols

1a, 1b Communication application means 2a, 2b Path measurement means 3 Topology management means 4a, 4b Quality measurement means 5 Congestion judgment means 6 Network 7a, 7b End host 8 Network management server

Claims (14)

A path measuring means for measuring a communication path between end hosts under a system including an end host connected to the network and one or more communication devices provided on the network between the end hosts; A quality measuring means for measuring the communication quality of the network and a congestion judging means for judging network congestion are provided in either the end host or the one or more communication devices, respectively, and the network congestion scale in the communication between the end hosts is determined. A method of determining,
A route measuring step in which a route measuring means measures a communication path of a network link in communication between end hosts in units of sessions;
A quality measuring step in which the quality measuring means measures the communication quality of the network in communication between end hosts in units of sessions;
Congestion scale means determines the network link communication quality in the communication between end hosts by determining the communication quality of the network link on a session basis based on the measured communication path and communication quality; and
A network congestion scale determination method characterized by comprising: Furthermore, topology management means for managing network topology information is provided,
In the path measuring step, the topology management means periodically collects topology information from communication devices on the network including routers, and the path measurement means measures the communication path based on the topology information. The network congestion scale determination method according to claim 1. 2. The network congestion scale determination method according to claim 1, wherein in the route measuring step, the route measuring means measures the communication route by directly searching the opposite end host for the route. In the path measuring step, the path measuring unit according to claim 1 measures the communication path, the topology managing unit according to claim 2 collects the topology information, and the path measuring unit according to claim 3 directly selects the opposite end host. The network congestion scale determination method according to any one of claims 1 to 3, wherein a timing for searching for a route is set at the start of a session or periodically. 5. The network congestion scale determination according to claim 1, wherein in the quality measurement step, the quality measurement unit measures the communication quality by comparing the communication quality with a threshold value at a network level or an application level. Method. In the congestion determination step, the congestion determination means compares the whole network link unit, normal and abnormal session numbers with at least one or more thresholds based on the measured communication path and communication quality, 6. The network congestion scale determination method according to claim 1, wherein the network congestion scale is determined. The network congestion according to any one of claims 1 to 6, wherein in the congestion determination step, the congestion determination means further receives a congestion inquiry request and responds with a determination result of the network congestion scale. Scale determination method. A system comprising: an end host connected to a network; and one or more communication devices provided on the network between the end hosts, the system determining a network congestion scale in the communication between the end hosts,
A path measuring means for measuring a communication path of a network link in communication between end hosts in units of sessions;
Quality measurement means for measuring communication quality of the network in communication between end hosts in units of sessions;
Based on the measured communication path and communication quality, a network link communication quality is obtained for each session, and a congestion determination means for determining a network congestion scale in communication between end hosts is provided.
The network congestion scale determination system, wherein the path measurement unit, the quality measurement unit, and the congestion determination unit are provided in either the end host or one or more communication devices, respectively. Furthermore, it comprises topology management means for periodically collecting and managing topology information from communication devices on the network including the router,
The network congestion scale determination system according to claim 8, wherein the path measurement unit measures a communication path based on the collected topology information. 9. The network congestion scale determination system according to claim 8, wherein the route measuring unit measures the communication route by directly searching the opposite end host for the route. The path measurement unit according to claim 8 measures the communication path, the topology management unit according to claim 9 collects the topology information, and the path measurement unit according to claim 10 searches the path directly with respect to the opposite end host. The network congestion scale determination system according to any one of claims 8 to 10, wherein the timing is set at the start of a session or periodically. 12. The network congestion scale determination system according to claim 8, wherein the quality measurement unit measures the communication quality by comparing it with a threshold value at a network level or an application level. The congestion determination means determines the network congestion scale by comparing the whole network link unit, the number of normal and abnormal sessions with at least one or more thresholds based on the measured communication path and communication quality. The network congestion scale determination system according to any one of claims 8 to 12, characterized in that: The network congestion scale determination method according to any one of claims 8 to 13, wherein the congestion determination unit further receives a congestion inquiry request and responds with a determination result of the network congestion scale.

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