JP3950093B2

JP3950093B2 - Quality degradation link usage rate estimation method and apparatus

Info

Publication number: JP3950093B2
Application number: JP2003313684A
Authority: JP
Inventors: 亮一川原; 圭介石橋; 卓也朝香
Original assignee: Nippon Telegraph and Telephone Corp
Current assignee: Nippon Telegraph and Telephone Corp
Priority date: 2003-09-05
Filing date: 2003-09-05
Publication date: 2007-07-25
Anticipated expiration: 2023-09-05
Also published as: JP2005086303A

Description

本発明は、品質劣化リンク使用率推定方法およびその装置に係り、特に、ＩＰネットワークの通信品質を維持・管理するために必要となる、通信品質劣化が開始するリンク使用率を推定する方法に関する。 The present invention relates to a quality degradation link usage rate estimation method and apparatus, and more particularly to a method for estimating a link usage rate at which communication quality degradation starts, which is necessary for maintaining and managing the communication quality of an IP network.

ＩＰネットワークが広く利用されてくるに伴って、ＩＰネットワーク上での通信品質保証に対する要求が高まっている。
現状のＩＰネットワーク管理においては、あるリンクが輻輳しているか否かは予め定めたリンク使用率に対するしきい値と測定されたリンク使用率を比較して判定している。（下記非特許文献１、非特許文献２、非特許文献３参照）
しかし、リンク使用率とユーザの体感するファイル転送時間やスループット等の品質との関連が不明であるため、輻輳状態と判定する使用率に対するしきい値を具体的に特定することが困難であった。
また、リンクを通過するフローのファイル転送時間やスループットを測定し、その平均等の統計値が、ある閾値以下になった場合を輻輳状態と判定する方法は、下記のような問題点があった。
（１）ファイル転送時間やスループットといったユーザ品質測定は、当該リンク上を通過する全てのパケットをキャプチャしフローを組み上げて算出するか（下記非特許文献４参照）、もしくは当該リンクの前段か後段もしくは両方に試験パケット送受信機を設置して、試験パケットを送信することによって品質測定を能動的に行う必要があり（下記非特許文献５参照）、一般的にこれらはデータ蓄積のためのリソースが必要となるか専用の測定装置が必要となりコストが増大してしまう。
（２）当該リンクがボトルネックでない場合であっても、当該リンクを通過するフローの通過する前後のネットワークの状態によって平均スループットはネットワークごとに異なり、ファイル転送時間やスループットに対する具体的な閾値の設定が困難である With the widespread use of IP networks, there is an increasing demand for communication quality assurance on IP networks.
In the current IP network management, whether or not a certain link is congested is determined by comparing a threshold for a predetermined link usage rate with a measured link usage rate. (See Non-Patent Document 1, Non-Patent Document 2, and Non-Patent Document 3 below)
However, since the relationship between the link usage rate and the quality such as the file transfer time and throughput experienced by the user is unknown, it is difficult to specify the threshold for the usage rate that is judged to be a congestion state. .
In addition, the method of measuring the file transfer time and throughput of a flow that passes through the link and determining that the statistical value such as the average falls below a certain threshold value is a congestion state has the following problems. .
(1) User quality measurement such as file transfer time and throughput is calculated by capturing all packets passing through the link and assembling the flow (see Non-Patent Document 4 below), or before or after the link or It is necessary to install test packet transceivers on both sides and actively perform quality measurement by transmitting test packets (see Non-Patent Document 5 below). Generally, these require resources for data storage. In other words, a dedicated measuring device is required and the cost increases.
(2) Even if the link is not a bottleneck, the average throughput varies from network to network depending on the state of the network before and after the flow passing through the link, and specific threshold settings for file transfer time and throughput are set. Is difficult

そのため、本願の発明者らは、特願２００２−０１６３３０号「通信品質管理方法及びその実施装置並びにその処理プログラムと記憶媒体」において、測定が簡易な同時接続フロー数とリンク使用率もしくはパケット損失率という値のみから当該リンクが輻輳しているか否か、当該リンクにおいて品質が劣化しているか否かを判定し、通信品質を管理する方法を提案した。
この方法では、リンク使用率や平均スループットに対して予めしきい値を設けることなく、同時接続フロー数の挙動から品質が劣化しているか否かを判定できる。
また、本願の発明者らは、特願２００３−０１４３４１号「通信帯域算出方法及び通信帯域算出装置」において、通信品質を向上させるためには、当該リンクの通信帯域をどれ位増設すればよいかといった通信帯域設計方法を提案した。
前述の２つの発明は、あるリンクを通過するフローの品質（平均ファイル転送時間やスループットの平均）は当該リンクがボトルネックとなっていない場合には負荷に係わらず一定であり、かつ平均同時接続フロー数と平均リンク使用率は比例関係となること、また当該リンクがボトルネックとなる場合には品質の劣化が観測され、平均同時接続フロー数が平均リンク使用率に対して、非線形的に増加するという現象を利用している（図１）。 Therefore, the inventors of the present application disclosed in Japanese Patent Application No. 2002-016330 “Communication quality management method and apparatus for implementing the same, and processing program and storage medium thereof”, the number of simultaneous connection flows and the link usage rate or packet loss rate that are easy to measure. From this value, it was determined whether or not the link is congested and whether or not the quality of the link is degraded, and a method for managing communication quality was proposed.
In this method, it is possible to determine whether or not the quality is deteriorated from the behavior of the number of simultaneous connection flows without providing a threshold in advance for the link usage rate and the average throughput.
In addition, in the Japanese Patent Application No. 2003-014341 “Communication Band Calculation Method and Communication Band Calculation Device”, the inventors of the present application need to increase the communication band of the link in order to improve the communication quality. A communication bandwidth design method was proposed.
In the above two inventions, the flow quality (average file transfer time and average throughput) passing through a link is constant regardless of the load when the link is not a bottleneck, and the average simultaneous connection There is a proportional relationship between the number of flows and the average link usage rate, and when the link becomes a bottleneck, quality degradation is observed, and the average concurrent connection flow rate increases nonlinearly with respect to the average link usage rate. This phenomenon is used (Fig. 1).

特願２００２−０１６３３０号では、フロー数が非線形増加領域に属した時間の割合を品質劣化度と定義し、品質を管理する方法を発明した。
特願２００３−０１４３４１号では、通信品質を維持するためには、フロー数が非線形増加を開始するような閾値ρ^＊以下にリンク使用率を抑えればよいとの考えに基づいている。
現在の通信帯域Ｃを、Ｃｎｅｗ＝Ｃ×ρ＿ｍａｘ／ρ^＊に増設すれば、観測された中での最大負荷ρ＿ｍａｘ（＝トラヒック量Ｂ＿ｍａｘ［ｂｐｓ］／Ｃ［ｂｐｓ］）が加わっても、そのときのリンク使用率は下記（３）式で表され、全ての負荷において、フロー数は線形増加する（＝ファイル転送時間は一定に維持できる）ことになる（図２）。
［数３］
Ｂ＿ｍａｘ／Ｃｎｅｗ＝Ｂ＿ｍａｘ／｛Ｃ×ρ＿ｍａｘ／ρ^＊｝＝ρ^＊
・・・・・・・・・・・・・・・・・・（３）
この発明では、ρ^＊をフロー数が線形増加する領域に属するリンク使用率の最大値により推定していた。例えば、図１では右から３番目の×のポイントがそれに相当する。 In Japanese Patent Application No. 2002-016330, the ratio of the time in which the number of flows belonged to the non-linear increase region was defined as the degree of quality deterioration, and a method for managing quality was invented.
Japanese Patent Application No. 2003-014341 is based on the idea that in order to maintain the communication quality, it is sufficient to suppress the link usage rate below a threshold value ρ ^{* at} which the number of flows starts a non-linear increase.
If the current communication band C is added to Cnew = C × ρ_max / ρ ^* , even if the observed maximum load ρ_max (= traffic amount B_max [bps] / C [bps]) is added, The link usage rate is expressed by the following equation (3), and the number of flows increases linearly (= the file transfer time can be kept constant) in all loads (FIG. 2).
[Equation 3]
B_max / Cnew = B_max / {C × ρ_max / ρ ^* } = ρ ^*
(3)
In the present invention, ρ ^* is estimated from the maximum value of the link usage rate belonging to the region where the number of flows increases linearly. For example, in FIG. 1, the third x point from the right corresponds to that.

なお、本願発明に関連する先行技術文献としては以下のものがある。
N.Ansari,G.Cheng,S.Israel,Y.Luo,J.Ma,and L.Zhu,“QoS provision with path protection for next generation SONET,”ICC2002,2002. A.Feldmann,A.Greenberg,C,Lund,N.Reingold,and J.Rexford,“Netscope:Traffic engineering for IP networks,”IEEE Network,pp.11-19,March/Apr 2000. A.Kumar,M.Hegde,S.V.R.Anand,B.N.Bindu,D.Thirumurthy,and A.A.Kherani,“Nonintrusive TCP connection admission control for bandwidth management of an Internet access link,”IEEE Commun.Mag.,pp.160-167,May 2000. J.Quittek,T.Zseby,G.Carle,and S.zander,“Traffic flow measurements within IP networks: requirements,technologies and standardization,”IEEE SAINT 2002,pp.97-98,2002. “CAIDA (cooperative association for Internet data analysis),”http://www.caida.org/tgols/. 特願２００２−０１６３３０号「通信品質管理方法及びその実施装置並びにその処理プログラムと記憶媒体」特願２００３−０１４３４１号「通信帯域算出方法及び通信帯域算出装置」 As prior art documents related to the invention of the present application, there are the following.
N. Ansari, G. Cheng, S. Israel, Y. Luo, J. Ma, and L. Zhu, “QoS provision with path protection for next generation SONET,” ICC 2002, 2002. A. Feldmann, A. Greenberg, C, Lund, N. Reingold, and J. Rexford, “Netscope: Traffic engineering for IP networks,” IEEE Network, pp. 11-19, March / Apr 2000. A. Kumar, M. Hegde, SVRAnand, BNBindu, D. Thirumurthy, and AAKherani, “Nonintrusive TCP connection admission control for bandwidth management of an Internet access link,” IEEE Commun. Mag., Pp. 160-167, May 2000. J. Quitektek, T. Zseby, G. Carle, and S. zander, “Traffic flow measurements within IP networks: requirements, technologies and standardization,” IEEE SAINT 2002, pp. 97-98, 2002. “CAIDA (cooperative association for Internet data analysis),” http://www.caida.org/tgols/. Japanese Patent Application No. 2002-016330 “Communication Quality Management Method, Apparatus for Implementing the Same, Processing Program and Storage Medium” Japanese Patent Application No. 2003-014341 “Communication Band Calculation Method and Communication Band Calculation Device”

しかしながら、図１に示すように、フロー数の測定値に関するばらつきが非常に小さい場合は、その方法でρ^＊の推定は可能であるが、測定値に関してばらつきがある場合（例えば、図３、これはシミュレーション実験により得られた結果である）には、ρ^＊の決定は困難であり、何らかの統計的手法に基づいた推定方法が必要となる。
また、特願２００３−０１４３４１号では、特願２００２−０１６３３０号において定義した品質劣化度とリンク使用率ρ^＊の関係については何も考慮されておらず、例えば、品質劣化度をある値以下に抑えるには、リンク使用率の基準値ρ^＊をどのように決定すべきかといった場合には対応していなかった。
本発明は、前記従来技術の問題点を解決するためになされたものであり、本発明の目的は、トラヒック条件に対する仮定を設けることなく、測定が簡易な同時接続フロー数と使用率という値のみから当該リンクにおいてＴＣＰレベルでの通信品質の劣化が開始するリンク使用率を推定する品質劣化リンク使用率推定方法および品質劣化リンク使用率推定装置を提供することにある。
本発明の前記ならびにその他の目的と新規な特徴は、本明細書の記述及び添付図面によって明らかにする。 However, as shown in FIG. 1, when the variation in the measured value of the number of flows is very small, it is possible to estimate ρ ^{* by} the method, but there is a variation in the measured value (for example, FIG. Is a result obtained by a simulation experiment), it is difficult to determine ρ ^* , and an estimation method based on some statistical method is required.
In Japanese Patent Application No. 2003-014341, nothing is taken into consideration regarding the relationship between the quality degradation level and the link usage rate ρ ^* defined in Japanese Patent Application No. 2002-016330. For example, the quality degradation level is set to a certain value or less. In order to suppress, it did not correspond to the case of how to determine the reference value ρ ^* of the link usage rate.
The present invention has been made to solve the above-described problems of the prior art, and the object of the present invention is to provide only the values of the number of simultaneously connected flows and the usage rate that are easy to measure without making assumptions about traffic conditions. Therefore, it is intended to provide a quality degradation link usage rate estimation method and a quality degradation link usage rate estimation device for estimating a link usage rate at which communication quality degradation at the TCP level starts in the link.
The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

本願において開示される発明のうち、代表的なものの概要を簡単に説明すれば、下記の通りである。
本発明の前提となる第１の品質劣化リンク使用率推定方法においては、予め定めた時間間隔ｔ０における当該リンクを通過するフローの平均同時接続数Ｎｉを測定し、当該リンクの平均使用率ρｉ（ｉ＝１,...,ｎ）を測定し、それらｎ個の測定値の組み合わせ（Ｎｉ，ρｉ）から当該リンクにおける品質劣化度を算出する関数Ｆ（Ｎｉ，ρｉ）を構築し、品質劣化度に対する目標値δを予め定めておき、あるρ＿ｔｈに対して、ρｋ＜ρ＿ｔｈとなる組（Ｎｋ，ρｋ）を抽出し、当該組（Ｎｋ，ρｋ）に対して、Ｆ（Ｎｋ，ρｋ）＜δを満たす最大のρ＿ｔｈを品質劣化が開始するリンク使用率として推定することを特徴とする。
ここで、品質劣化度算出関数Ｆ（Ｎｉ、ρｉ）は、以下に示す第２から第８のいずれかの方法で具体的に構築する。 Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
In the first quality degradation link usage rate estimation method which is the premise of the present invention, the average simultaneous connection number Ni of flows passing through the link at a predetermined time interval t0 is measured, and the average usage rate ρi ( i = 1,..., n) is measured, and a function F (Ni, ρi) for calculating the quality degradation degree in the link is constructed from a combination (Ni, ρi) of these n measurement values, and the quality degradation A target value δ for the degree is determined in advance, and for a certain ρ_th, a set (Nk, ρk) that satisfies ρk <ρ_th is extracted, and for the set (Nk, ρk), F (Nk, ρk) < The maximum ρ_th that satisfies δ is estimated as the link usage rate at which quality degradation starts.
Here, the quality deterioration degree calculation function F (Ni, ρi) is specifically constructed by any one of the second to eighth methods described below.

本発明の前提となる第２の品質劣化リンク使用率推定方法においては、予め定めた時間間隔ｔ０における当該リンクを通過するフローの平均同時接続数Ｎｉと、当該リンクの平均使用率ρｉ（ｉ＝１,...,ｎ）を測定し、それらｎ個の測定値の組み合わせ（Ｎｉ，ρｉ）のうち、予め定めた閾値ρ＿０に対して、ρｊ＜ρ＿０となる測定値（Ｎｊ，ρｊ）を用いて、平均リンク使用率当たりの平均同時接続フロー数Ｒを算出し、ｎ個の組み合わせ（Ｎｉ，ρｉ）、Ｒ、および予め定めた閾値εとρ＿１を用いて、あるρ＿ｔｈに対して、ρｋ＜ρ＿ｔｈとなる組（Ｎｋ，ρｋ）を抽出し、その組数をｎ’とし、その中で、ρｋ＞ρ＿１、かつ、平均同時接続フロー数Ｎｋが、Ｎｋ＞ρｋ×（Ｒ×（１＋ε））となる組（Ｎｋ，ρｋ）を「ρｋ＜ρ＿ｔｈという条件の下での品質劣化状態の組」として抽出し、その組数をｍとし、ｄ＝ｍ／ｎ’をρｋ＜ρ＿ｔｈという条件の下での品質劣化度とし、同様の手順を様々なρ＿ｔｈに対して行い、品質劣化度ｄが予め定めた劣化度目標値δ以下となるような最大のρ＿ｔｈを、品質劣化が開始するリンク使用率として推定する。 In the second quality deterioration link usage rate estimation method which is the premise of the present invention, the average simultaneous connection number Ni of flows passing through the link in a predetermined time interval t0 and the average usage rate ρi (i = 1, ..., n), and among these n combinations of measured values (Ni, ρi), a measured value (Nj, ρj) satisfying ρj <ρ_0 with respect to a predetermined threshold value ρ_0. To calculate the average number of simultaneous connection flows R per average link usage rate, and use n combinations (Ni, ρi), R, and predetermined thresholds ε and ρ_1, and ρk for a certain ρ_th. A set (Nk, ρk) that satisfies <ρ_th is extracted, and the number of sets is n ′, in which ρk> ρ_1, and the average simultaneous connection flow number Nk is Nk> ρk × (R × (1 + ε) ) Is a group (Nk, ρk) with the condition “ρk <ρ_th”. As a set of quality degradation states under the condition “,” the number of sets is m, d = m / n ′ is the quality degradation degree under the condition of ρk <ρ_th, and the same procedure is applied to various ρ_th. The maximum ρ_th at which the quality degradation level d is equal to or less than a predetermined degradation level target value δ is estimated as the link usage rate at which the quality degradation starts.

本発明の前提となる第３の品質劣化リンク使用率推定方法においては、第２の方法における（Ｎｉ、ρｉ）（ｉ＝１,...,ｎ）の測定をＭ回実施し、Ｉ番目のデータセット（Ｉ＝１〜Ｍ）に対して、本発明の第２の発明と同様の手順により、品質劣化度ｄの値を計算し、その結果をｄ（Ｉ）とし、｛ｄ（１），ｄ（２），...ｄ（Ｍ）｝を用いて、その算術平均ｄ＿ａｖｅと片側ｘ％信頼区間ｄ＿ｘを求め、ｄ＿ａｖｅ＋ｄ＿ｘが予め定めた劣化度目標値δ以下となるような最大のρ＿ｔｈを、品質劣化が開始するリンク使用率として推定する。
本発明の第１の品質劣化リンク使用率推定方法においては、本発明の前提となる第２の方法と同様に（Ｎｉ，ρｉ）の測定およびＲの算出を行い、予め定めたリンク使用率に対する区間幅Δ_ρを用い、区間［（ｊ−１）Δ_ρ，ｊΔ_ρ］に属する（Ｎｉ、ρｉ）を抽出し、その組数をｎｊとし、抽出された（Ｎｉ、ρｉ）を用いて区間［（ｊ−１）Δ_ρ，ｊΔ_ρ］におけるＥ［Ｎ］とρの関係を表す一次関数Ｅ［Ｎ］＝αｊ＋βｊ×ρの係数αｊ、βｊを最小自乗法により求め、これをｊ＝１〜１／Δ_ρについて実施し、区間［（ｊ−１）Δ_ρ，ｊΔ_ρ］におけるρに対し、測定される平均同時接続フロー数Ｎが、平均Ｅ［Ｎ｜ρ］＝αｊ＋βｊ×ρ、分散Ｖ［Ｎ｜ρ］＝［Σ｛Ｎｉ−（αｊ＋βｊ×ρ）｝^２／（ｎｊ−２）］の正規分布に従うとし、予め定めた閾値εを用いて、ρｉに対して確率Ｐ［Ｎ＞（１＋ε）×Ｒ×ρｉ｜ρｉ］を平均Ｅ［Ｎ｜ρｉ］、分散＝Ｖ［Ｎ｜ρｉ］の正規分布を用いて計算しておき、これをｉ＝１〜ｎについて実施し、ρｋ＜ρ＿ｔｈとなる組（Ｎｋ、ρｋ）の数をｎ’とし、そのときのインデックスｋの集合をＳρ＿ｔｈとし、ρｋ＜ρ＿ｔｈという条件の下での品質劣化度ｄを、ｄ＝Σ_{ｋ∈Ｓｐ＿ｔｈ}Ｐ［Ｎ＞（１＋ε）×Ｒ×ρｋ｜ρｋ］／ｎ’により算出し、同様の手順を様々なρ＿ｔｈに対して行い、品質劣化度ｄが予め定めた劣化度目標値δ以下となるような最大のρ＿ｔｈを、品質劣化が開始するリンク使用率として推定する。 In the third quality degradation link usage rate estimation method as the premise of the present invention, the measurement of (Ni, ρi) (i = 1,..., N) in the second method is performed M times, and the I th For the data set (I = 1 to M), the quality degradation degree d is calculated by the same procedure as in the second invention of the present invention, and the result is d (I), and {d (1 ), D (2),... D (M)}, the arithmetic mean d_ave and the one-sided x% confidence interval d_x are obtained, and the maximum such that d_ave + d_x is equal to or less than the predetermined degradation degree target value δ. ρ_th is estimated as a link usage rate at which quality degradation starts.
In the first quality degradation link usage rate estimation method of the present invention , (Ni, ρi) is measured and R is calculated in the same manner as the second method which is the premise of the present invention, and the predetermined link usage rate is determined. using interval width delta _[rho, the interval _{[(j-1) Δ ρ} , jΔ ρ] belongs to (Ni, .rho.i) to extract, and the number of sets and nj, the extracted (Ni, .rho.i) using the section _{[(j-1) Δ ρ} , jΔ ρ] calculated by the least square method E [N] primary function E represents a relationship between [rho [N] at = αj + βj × coefficient [rho .alpha.j, the .beta.j, this j = 1 performed on to 1 / delta _[rho, the interval _{[(j-1) Δ ρ} , jΔ ρ] to [rho in average concurrent flow number N to be measured, the average E [N | ρ] = αj + βj × ρ, distributed V [N | ρ] = [ Σ {Ni- (αj + βj × ρ)} 2 / (nj-2)] and follows a normal distribution of the previously constant By using the threshold epsilon, the probability P against ρi [N> (1 + ε ) × R × ρi | ρi] Average E [N | ρi], variance = V | computed using the normal distribution of [N .rho.i] Then, this is performed for i = 1 to n, the number of pairs (Nk, ρk) where ρk <ρ_th is n ′, the set of indices k at that time is Sρ_th, and the condition of ρk <ρ_th is satisfied. The quality degradation degree d below is calculated by d = _{ΣkεSp_th} P [N> (1 + ε) × R × ρk | ρk] / n ′, and the same procedure is performed for various ρ_ths, so that the quality degradation The maximum ρ_th at which the degree d is equal to or less than a predetermined deterioration degree target value δ is estimated as the link usage rate at which the quality deterioration starts.

本発明の第２の品質劣化リンク使用率推定方法においては、本発明の前提となる第２の方法と同様に（Ｎｉ，ρｉ）の測定およびＲの算出を行い、予め定めたリンク使用率に対する区間幅Δ_ρを用い、区間［（ｊ−１）Δ_ρ，ｊΔ_ρ］に属する（Ｎｉ、ρｉ）を抽出し、抽出された（Ｎｉ、ρｉ）を用いて区間［（ｊ−１）Δ_ρ，ｊΔ_ρ］におけるＥ［Ｎ］とρの関係を表す一次関数Ｅ［Ｎ］＝αｊ＋βｊ×ρの係数αｊ、βｊを最小自乗法により求め、これをｊ＝１〜１／Δ_ρについて実施し、区間［（ｊ−１）Δ_ρ，ｊΔ_ρ］におけるρに対し、測定される平均同時接続フロー数Ｎが、平均Ｅ［Ｎ｜ρ］＝αｊ＋βｊ×ρ、分散Ｖ［Ｎ｜ρ］＝［Σ｛Ｎｉ−（αｊ＋βｊ×ρ）｝^２／（ｎｊ−２）］の正規分布に従うとし、ρ＜ρ＿ｔｈという条件の下でのρに対する確率密度関数ｇ_ρ＿ｔｈ（ρ）を与えて、ρ＜ρ＿ｔｈにおける品質劣化度ｄを、下記（４）式により算出し、同様の手順を様々なρ＿ｔｈ、に対して行い、品質劣化度ｄが予め定めた劣化度目標値δ以下となるような最大のρ＿ｔｈを、品質劣化が開始するリンク使用率として推定する。
［数４］
ｄ＝∫Ｐ［Ｎ＞（１＋ε）×Ｒ×ρ｜ρ］×ｇ_ρ＿ｔｈ（ρ）ｄρ
・・・・・・・・・・・・・・・・・・（４） In the second quality degradation link usage rate estimation method of the present invention , (Ni, ρi) is measured and R is calculated in the same manner as the second method which is the premise of the present invention, and the predetermined link usage rate is determined. using interval width delta _[rho, the interval _{[(j-1) Δ ρ} , jΔ ρ] extracts belongs (Ni, .rho.i), the extracted (Ni, .rho.i) using the interval [(j-1) Δ _{_ρ, jΔ ρ} E in] [N] and a linear function E represents the relationship ρ [N] = αj + βj × coefficient [rho .alpha.j, determined by the method of least squares .beta.j, this for j = 1~1 / Δ _ρ embodiment then, the interval _{[(j-1) Δ ρ} , jΔ ρ] to [rho in average concurrent flow number N to be measured, the average E [N | ρ] = αj + βj × ρ, variance V [N | [rho] = [Σ {Ni- (αj + βj × ρ)} 2 / (nj-2)] and follows a normal distribution of, [rho <under the condition that ρ_th giving the probability density function g _{ρ_th} (ρ) for the [rho, [rho <quality degradation degree d in Ro_th, calculated by the following equation (4), the same procedure various Ro_th, relative to the quality deterioration degree d Is estimated as the link usage rate at which the quality degradation starts.
[Equation 4]
d = ∫P [N> (1 + ε) × R × ρ | ρ] × g _{ρ_th} (ρ) dρ
(4)

本発明の第３の品質劣化リンク使用率推定方法においては、本発明の前提となる第２の方法において同時に当該リンクにおけるパケット損失率Ｌｉも同時に測定し、本発明の前提となる第２の方法において、ρｋ＞ρ＿１、かつ、平均同時接続フロー数Ｎｋが、Ｎｋ＞ρｋ×（Ｒ×（１＋ε））となる組（Ｎｋ，ρｋ）を品質劣化状態の組として抽出していた代わりに、予め定めた閾値Ｌ１に対してパケット損失率Ｌｋ＞Ｌ１、かつ、平均同時接続フロー数Ｎｋが、Ｎｋ＞ρｋ×（Ｒ×（１＋ε））となる組（Ｎｋ，ρｋ）を品質劣化状態の組として抽出し、当該組（Ｎｋ，ρｋ）を用いて、本発明の前提となる第２または第３の方法で、品質劣化が開始するリンク使用率を推定する。
本発明の第４の品質劣化リンク使用率推定方法においては、本発明の第３の方法において、前記ｎ個の測定値の組み合わせ（Ｎｉ，ρｉ）のうち、予め定めた閾値ρ＿０に対して、ρｊ＜ρ＿０となる測定値（Ｎｊ，ρｊ）を用いて、平均リンク使用率当たりの平均同時接続フロー数Ｒを算出する代わりに、予め定めた閾値Ｌ０に対してＬｊ＜Ｌ０の場合の測定値（Ｎｊ，ρｊ）を用いて平均リンク使用率当たりの平均同時接続フロー数Ｒを算出し、当該平均リンク使用率当たりの平均同時接続フロー数Ｒを用いて、本発明の第３の方法で、品質劣化が開始するリンク使用率を推定する。 In the third quality degradation link utilization estimation method of the present invention, also simultaneously measured packet loss rate Li in the same time the link in the second method as a premise of the present invention, a second method which is a premise of the present invention In the above example, a group (Nk, ρk) in which ρk> ρ_1 and the average simultaneous connection flow number Nk is Nk> ρk × (R × (1 + ε)) is extracted as a group of quality degradation states in advance. A set (Nk, ρk) in which the packet loss rate Lk> L1 and the average number of simultaneous connection flows Nk satisfy Nk> ρk × (R × (1 + ε)) with respect to the determined threshold L1 is a set of quality degradation states. Using this set (Nk, ρk), the link usage rate at which quality degradation starts is estimated by the second or third method which is the premise of the present invention.
In the fourth quality degradation link usage rate estimation method of the present invention, in the third method of the present invention, among the n measurement value combinations (Ni, ρi), a predetermined threshold value ρ_0, Instead of calculating the average simultaneous connection flow number R per average link usage rate using the measurement values (Nj, ρj) that satisfy ρj <ρ_0, the measurement values when Lj <L0 with respect to a predetermined threshold L0 (Nj, ρj) is used to calculate the average simultaneous connection flow number R per average link usage rate, and the average simultaneous connection flow number R per average link usage rate is used in the third method of the present invention. Estimate the link usage rate where quality degradation starts.

本発明の第５の品質劣化リンク使用率推定方法においては、本発明の前提となる第２の方法において同時に当該リンクにおけるパケット損失率Ｌｉも測定し、前記ｎ個の測定値の組み合わせ（Ｎｉ，ρｉ）のうち、予め定めた閾値ρ＿０に対して、ρｊ＜ρ＿０となる測定値（Ｎｊ，ρｊ）を用いて、平均リンク使用率当たりの平均同時接続フロー数Ｒを算出する代わりに、予め定めた閾値Ｌ０に対してＬｊ＜Ｌ０の場合の測定値（Ｎｊ，ρｊ）を用いて、平均リンク使用率当たりの平均同時接続フロー数Ｒを算出し、当該平均リンク使用率当たりの平均同時接続フロー数Ｒを用いて、本発明の第１から第４のいずかの方法で品質劣化が開始するリンク使用率を推定する。
また、本発明は、前述の品質劣化リンク使用率推定方法を実施する品質劣化リンク使用率推定装置である。 In the fifth quality deterioration link usage rate estimation method of the present invention, the packet loss rate Li in the link is also measured at the same time in the second method as the premise of the present invention, and the combination of the n measurement values (Ni, ρi), instead of calculating the average simultaneous connection flow number R per average link usage rate using a measured value (Nj, ρj) that satisfies ρj <ρ_0 with respect to a predetermined threshold ρ_0. The average simultaneous connection flow number R per average link usage rate is calculated using the measured value (Nj, ρj) when Lj <L0 with respect to the threshold L0, and the average simultaneous connection flow per average link usage rate The number R is used to estimate the link usage rate at which quality degradation starts in any of the first to fourth methods of the present invention.
Further, the present invention is a quality deteriorated link usage rate estimation apparatus that performs the above-described quality deteriorated link usage rate estimation method.

本願において開示される発明のうち代表的なものによって得られる効果を簡単に説明すれば、下記の通りである。
本発明によれば、観測が簡易な同時接続フロー数と使用率という値のみからそれらの関係を算出することにより、当該リンクにおいて品質劣化が開始するリンク使用率を推定する方法及びその装置を提供することができる。 The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
According to the present invention, there is provided a method and apparatus for estimating a link usage rate at which quality degradation starts in the link by calculating the relationship between only the number of simultaneous connection flows and the usage rate, which can be easily observed. can do.

以下、図面を参照して本発明の実施の形態を詳細に説明する。
［実施例１］
図４は、本発明の品質劣化リンク使用率推定装置が適用されるＩＰネットワークの基本構成の一例を示す構成図である。
同図に示すように、本発明の品質劣化リンク使用率推定装置１は、前段ノード２と後段ノード３との間のリンクに挿入される形態で利用される。
図５は、本発明の実施例１の品質劣化リンク使用率推定装置１の一例の概略構成を示すブロック図である。
同図に示すように、本実施例の品質劣化リンク使用率推定装置１は、パケットヘッダ解析部１１と、リンク使用率算出部１２と、同時接続フロー数算出部１３と、同時接続フロー数および使用率管理部１４と、使用率当たりの同時接続フロー数算出部１５と、品質劣化リンク使用率推定部１６とから構成される。
図５に示すように、前段ノード１から到着したパケットは、パケットヘッダ解析部１１によって、パケットサイズ、ＴＣＰフラグ情報、ＩＰアドレス情報を読み取られたあと、後段ノードヘ送信される。
パケットヘッダ解析部１１によって読み取られたパケットサイズは、リンク使用率算出部１２へ通知される。
リンク使用率算出部１２は、一定時間ｔ０の間に通過したパケットのサイズの和をｔ０で割ったものを、さらにリンク帯域で割ることによって、ｔ０毎の平均使用率ρｉを算出し、これをｔ０時間毎に同時接続フロー数及び使用率管理部１４に通知する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[Example 1]
FIG. 4 is a configuration diagram showing an example of a basic configuration of an IP network to which the quality degradation link usage rate estimation apparatus of the present invention is applied.
As shown in the figure, the quality degradation link usage rate estimation device 1 of the present invention is used in a form of being inserted into a link between a preceding node 2 and a succeeding node 3.
Figure 5 is a Ru block diagram showing a schematic configuration of an example of the quality-degraded link utilization estimating apparatus 1 of the first embodiment of the present invention.
As shown in the figure, the quality degradation link usage rate estimation device 1 of this embodiment includes a packet header analysis unit 11, a link usage rate calculation unit 12, a simultaneous connection flow number calculation unit 13, a simultaneous connection flow number and The usage rate management unit 14 includes a simultaneous connection flow number calculation unit 15 per usage rate, and a quality degradation link usage rate estimation unit 16.
As shown in FIG. 5, a packet arriving from the preceding node 1 is transmitted to the succeeding node after the packet header analyzer 11 reads the packet size, TCP flag information, and IP address information.
The packet size read by the packet header analysis unit 11 is notified to the link usage rate calculation unit 12.
The link usage rate calculation unit 12 calculates an average usage rate ρi for each t0 by dividing the sum of the sizes of the packets passed during the predetermined time t0 by t0 and further dividing by the link bandwidth. The number of simultaneous connection flows and the usage rate management unit 14 are notified every t0 hours.

一方、ＴＣＰフラグ情報およびＩＰアドレス情報は、同時接続フロー数算出部１３に通知される。
同時接続フロー数算出部１３は、発信元ＩＰアドレス、着信先ＩＰアドレス、プロトコル番号、発信元ポート番号、着信先ポート番号を読み出し、新たな組み合わせをもつパケットが到着したら、新しいフロー発生とし、テーブルにそのアドレスの組とそのときのパケット到着時刻をエントリする。
もし既に同じ組を持つパケットがテーブルにエントリされていれば、そのパケット到着時刻を現在の時刻に更新する。ある組を持つパケットが最後に観測されてからタイムアウト値Ｔ０を超えたらフロー終了として、テーブルからその組を削除する。
同時接続フロー数算出部１３は、テーブルにエントリされている組の数をフロー数とし、ｔ０時間毎にこの値の平均値Ｎｉを算出し、同時接続フロー数及び使用率管理部１４に通知する。
使用率当りの同時接続フロー数算出部１５は、一定時間Ｔ（＞ｔ０）ごとに、同時接続フロー数及び使用率管理部１４から、同時接続フロー数Ｎｉおよび使用率ρｉ（ｉ＝１,...,ｎ）を読み出す。
使用率当りの同時接続フロー数算出部１５では、平均使用率ρｊが予め定めておいた閾値ρ＿０未満かどうかをチェックし、ρ＿０未満である（Ｎｊ，ρｊ）を用いて、最小自乗法により使用率当たりの平均同時接続フロー数Ｒを算出する。 On the other hand, the TCP flag information and the IP address information are notified to the simultaneous connection flow number calculation unit 13.
The simultaneous connection flow number calculation unit 13 reads a source IP address, a destination IP address, a protocol number, a source port number, and a destination port number. When a packet having a new combination arrives, a new flow is generated. The address set and the packet arrival time at that time are entered.
If a packet having the same set is already entered in the table, the packet arrival time is updated to the current time. When the timeout value T0 is exceeded after the last packet having a certain set is observed, the flow is terminated and the set is deleted from the table.
The simultaneous connection flow number calculation unit 13 sets the number of pairs entered in the table as the flow number, calculates an average value Ni of this value every t0 time, and notifies the simultaneous connection flow number and usage rate management unit 14 of the average value. .
The simultaneous connection flow number calculation unit 15 per usage rate receives a simultaneous connection flow number Ni and a usage rate ρi (i = 1,...) From the simultaneous connection flow number and usage rate management unit 14 every fixed time T (> t0). .., n) are read out.
The simultaneous connection flow number calculation unit 15 per usage rate checks whether the average usage rate ρj is less than a predetermined threshold ρ_0, and uses the least square method using (Nj, ρj) that is less than ρ_0. The average simultaneous connection flow number R per rate is calculated.

使用率当りの同時接続フロー数算出部１５は、計算した平均同時接続フロー数Ｒを品質劣化リンク使用率推定部１６に通知する。
品質劣化リンク使用率推定部１６は、同時接続フロー数及び使用率管理部１４から、同時接続フロー数Ｎｉおよび使用率ρｉ（ｉ＝１,...,ｎ）を読み出す。
品質劣化リンク使用率推定部１６は、ｎ個の組み合わせ（Ｎｉ，ρｉ）、Ｒ、および予め定めた閾値εとρ＿１を用いて、あるρ＿ｔｈに対して、ρｋ＜ρ＿ｔｈとなる組（Ｎｋ，ρｋ）を抽出し、その組数をｎ’とし、その中でρｋ＞ρ＿１、かつ、平均同時接続フロー数Ｎｋが、Ｎｋ＞ρｋ×（Ｒ×（１＋ε））となる組（Ｎｋ，ρｋ）を「ρｋ＜ρ＿ｔｈという条件の下での品質劣化状態の組」として抽出し、その組数をｍとし、ｄ＝ｍ／ｎ’をρｋ＜ρ＿ｔｈという条件の下での品質劣化度とし、同様の手順を様々なρ＿ｔｈに対して行い、品質劣化度ｄが予め定めた劣化度目標値δ以下となるような最大のρ＿ｔｈを求め、それを品質劣化が開始するリンク使用率として算出する。 The simultaneous connection flow number calculation unit 15 per usage rate notifies the quality degradation link usage rate estimation unit 16 of the calculated average simultaneous connection flow number R.
The quality degradation link usage rate estimation unit 16 reads the simultaneous connection flow number Ni and the usage rate ρi (i = 1,..., N) from the simultaneous connection flow number and usage rate management unit 14.
The quality degradation link usage rate estimation unit 16 uses n combinations (Ni, ρi), R, and predetermined threshold values ε and ρ_1, and a set (Nk, ρk) that satisfies ρk <ρ_th for a certain ρ_th. ), And the number of pairs is n ′, in which ρk> ρ_1, and the number of simultaneous simultaneous connection flows Nk is Nk> ρk × (R × (1 + ε)) (Nk, ρk) Extracted as “a set of quality deterioration conditions under the condition of ρk <ρ_th”, the number of the sets is m, and d = m / n ′ is the degree of quality deterioration under the condition of ρk <ρ_th. The procedure is performed for various ρ_ths, and the maximum ρ_th is obtained such that the quality degradation level d is equal to or less than a predetermined degradation level target value δ, and this is calculated as the link usage rate at which the quality degradation starts.

［実施例２］
本実施例では、リンク使用率算出部１２と、同時接続フロー数算出部１３とが、前記（Ｎｉ、ρｉ）（ｉ＝１,...,ｎ）の測定をＭ回実施して、同時接続フロー数および使用率管理部１４に通知する。
また、品質劣化リンク使用率推定部１６が、Ｉ番目のデータセット（Ｉ＝１〜Ｍ）に対して、品質劣化度ｄの値を計算し、その結果をｄ（Ｉ）とし、｛ｄ（１），ｄ（２），...ｄ（Ｍ）｝を用いて、その算術平均ｄ＿ａｖｅと片側ｘ％信頼区間ｄ＿ｘを求め、ｄ＿ａｖｅ＋ｄ＿ｘが予め定めた劣化度目標値δ以下となるような最大のρ＿ｔｈを、品質劣化が開始するリンク使用率として算出する。 [Example 2]
In the present embodiment, the link usage rate calculation unit 12 and the simultaneous connection flow number calculation unit 13 perform the measurement of (Ni, ρi) (i = 1,..., N) M times simultaneously. The number of connection flows and usage rate management unit 14 are notified.
Further, the quality degradation link usage rate estimation unit 16 calculates the value of the quality degradation degree d for the I-th data set (I = 1 to M), and sets the result as d (I), and {d ( 1), d (2),... D (M)} to obtain the arithmetic average d_ave and the one-sided x% confidence interval d_x, and the maximum such that d_ave + d_x is equal to or less than a predetermined degradation degree target value δ. Ρ_th is calculated as a link usage rate at which quality degradation starts.

［実施例３］
本実施例では、使用率当たりの同時接続フロー数算出部１５が、予め定めた閾値ρ＿０に対して、ρｊ＜ρ＿０となる測定値（Ｎｊ，ρｊ）を用いて、平均リンク使用率当たりの平均同時接続フロー数Ｒを算出する。
また、品質劣化リンク使用率推定部１６が、図１に示すように、予め定めたリンク使用率に対する区間幅Δ_ρを用い、区間［（ｊ−１）Δ_ρ，ｊΔ_ρ］に属する（Ｎｉ、ρｉ）を抽出し、その組数をｎｊとし、抽出された（Ｎｉ、ρｉ）を用いて区間［（ｊ−１）Δ_ρ，ｊΔ_ρ］におけるＥ［Ｎ］とρの関係を表す一次関数Ｅ［Ｎ］＝αｊ＋βｊ×ρの係数αｊ、βｊを最小自乗法により求め、これをｊ＝１〜１／Δ_ρについて実施し、区間［（ｊ−１）Δ_ρ，ｊΔ_ρ］におけるρに対し、測定される平均同時接続フロー数Ｎが、平均Ｅ［Ｎ｜ρ］＝αｊ＋βｊ×ρ、分散Ｖ［Ｎ｜ρ］＝［Σ｛Ｎｉ−（αｊ＋βｊ×ρ）｝^２／（ｎｊ−２）］の正規分布に従うとし、予め定めた閾値εを用いて、ρｉに対してＰ［Ｎ＞（１＋ε）×Ｒ×ρｉ｜ρｉ］を平均Ｅ［Ｎ｜ρｉ］、分散＝Ｖ［Ｎ｜ρｉ］の正規分布を用いて計算しておき、これをｉ＝１〜ｎについて実施し、ρｋ＜ρ＿ｔｈとなる組（Ｎｋ、ρｋ）の数をｎ’とし、そのときのインデックスｋの集合をＳ_ρ＿ｔｈとし、ρｋ＜ρ＿ｔｈという条件の下での品質劣化度ｄを、ｄ＝Σ_{ｋ∈Ｓｐ＿ｔｈ}Ｐ［Ｎ＞（１＋ε）×Ｒ×ρｋ｜ρｋ］／ｎ’により算出し、同様の手順を様々なρ＿ｔｈに対して行い、品質劣化度ｄが予め定めた劣化度目標値δ以下となるような最大のρ＿ｔｈを、品質劣化が開始するリンク使用率として算出する。 [Example 3]
In the present embodiment, the simultaneous connection flow number calculation unit 15 per usage rate uses a measured value (Nj, ρj) that satisfies ρj <ρ_0 with respect to a predetermined threshold ρ_0, and the average per average link usage rate. The number R of simultaneous connection flows is calculated.
Moreover, quality deterioration link utilization estimation unit 16, as shown in FIG. 1, using a section width delta _[rho against predetermined link utilization, the interval _{[(j-1) Δ ρ} , jΔ ρ] belongs to (Ni extracts .rho.i), and the number of sets and nj, the extracted (Ni, section by using ρi) [(j-1) Δ ρ, jΔ ρ] primary representing the relationship between E [N] and [rho in function E [N] = αj + βj × coefficient [rho .alpha.j, determined by the method of least squares .beta.j, which was carried out for j = 1~1 / Δ _ρ, the interval _{[(j-1) Δ ρ} , jΔ ρ] ρ in contrast, the average concurrent flow number N to be measured, the average E [N | ρ] = αj + βj × ρ, variance V [N | ρ] = [ Σ {Ni- (αj + βj × ρ)} 2 / (nj- and follows a normal distribution of 2), using the threshold epsilon a predetermined, P [N> (1 + ε) × R × ρi relative .rho.i | .rho.i] average E [ | Ρi], variance = V [N | ρi] is used for normal distribution, and this is performed for i = 1 to n, and the number of pairs (Nk, ρk) where ρk <ρ_th is n ′ The set of indexes k at that time is S _{ρ_th,} and the quality degradation degree d under the condition of ρk <ρ_th is defined as d = Σ _{kεSp_th} P [N> (1 + ε) × R × ρk | ρk] / n ′, the same procedure is performed for various ρ_th, and the maximum ρ_th such that the quality degradation degree d is equal to or less than a predetermined degradation degree target value δ is defined as the link usage rate at which the quality degradation starts. calculate.

［実施例４］
本実施例では、使用率当たりの同時接続フロー数算出部１５が、予め定めた閾値ρ＿０に対して、ρｊ＜ρ＿０となる測定値（Ｎｊ，ρｊ）を用いて、平均リンク使用率当たりの平均同時接続フロー数Ｒを算出する。
また、品質劣化リンク使用率推定部１６が、予め定めたリンク使用率に対する区間幅Δ_ρを用い、区間［（ｊ−１）Δ_ρ，ｊΔ_ρ］に属する（Ｎｉ、ρｉ）を抽出し、抽出された（Ｎｉ、ρｉ）を用いて区間［（ｊ−１）Δ_ρ，ｊΔ_ρ］におけるＥ［Ｎ］とρの関係を表す一次関数Ｅ［Ｎ］＝αｊ＋βｊ×ρの係数αｊ、βｊを最小自乗法により求め、これをｊ＝１〜１／Δ_ρについて実施し、区間［（ｊ−１）Δ_ρ，ｊΔ_ρ］におけるρに対し、測定される平均同時接続フロー数Ｎが、平均Ｅ［Ｎ｜ρ］＝αｊ＋βｊ×ρ、分散Ｖ［Ｎ｜ρ］＝［Σ｛Ｎｉ−（αｊ＋βｊ×ρ）｝^２／（ｎｊ−２）］の正規分布に従うとし、ρ＜ρ＿ｔｈという条件の下でのρに対する確率密度関数ｇ_ρ＿ｔｈ（ρ）を与えて、ρ＜ρ＿ｔｈにおける品質劣化度ｄを、前記（４）式により算出し、同様の手順を様々なρ＿ｔｈ、に対して行い、品質劣化度ｄが予め定めた劣化度目標値δ以下となるような最大のρ＿ｔｈを、品質劣化が開始するリンク使用率として算出する。 [Example 4]
In the present embodiment, the simultaneous connection flow number calculation unit 15 per usage rate uses a measured value (Nj, ρj) that satisfies ρj <ρ_0 with respect to a predetermined threshold ρ_0, and the average per average link usage rate. The number R of simultaneous connection flows is calculated.
Moreover, quality deterioration link utilization estimation unit 16, using the interval width delta _[rho against predetermined link utilization, the interval _{[(j-1) Δ ρ} , jΔ ρ] extracts belongs (Ni, .rho.i) to, extracted (Ni, ρi) section using _{[(j-1) Δ ρ} , jΔ ρ] in E [N] and a linear function E represents the relationship ρ [N] = αj + βj × coefficient [rho .alpha.j, .beta.j Is calculated with respect to _ρ in the interval [(j−1) Δ _ρ , jΔ _ρ ], and the average simultaneous connection flow number N is calculated as follows. It is assumed that the normal distribution of mean E [N | ρ] = αj + βj × ρ, variance V [N | ρ] = [Σ {Ni− (αj + βj × ρ)} ² / (nj−2)], and ρ <ρ_th _{Given the} probability density function g _{ρ_th} (ρ) for ρ under the above, the quality degradation degree d at ρ <ρ_th is expressed as (4 ), The same procedure is performed for various ρ_th, and the maximum ρ_th that causes the quality degradation degree d to be equal to or less than the predetermined degradation degree target value δ is the link usage rate at which the quality degradation starts. Calculate as

［実施例５］
本実施例では、図５に点線で示すように、同時接続フロー数および使用率管理部１４に前段ノード２から、前記リンクにおけるパケット損失率Ｌｉが入力される。
また、品質劣化リンク使用率推定部１６が、ρｋ＞ρ＿１、かつ、平均同時接続フロー数Ｎｋが、Ｎｋ＞ρｋ×（Ｒ×（１＋ε））となる組（Ｎｋ，ρｋ）を品質劣化状態の組として抽出していた代わりに、予め定めた閾値Ｌ１に対してパケット損失率Ｌｋ＞Ｌ１、かつ、予め定めた閾値εに対して平均同時接続フロー数Ｎｋが、Ｎｋ＞ρｋ×（Ｒ×（１＋ε））となる組（Ｎｋ，ρｋ）を品質劣化状態の組として抽出し、当該抽出した組（Ｎｋ，ρｋ）を用いて、前述実施例１または実施例２の方法により、品質劣化が開始するリンク使用率を算出する。 [Example 5]
In this embodiment, as indicated by a dotted line in FIG. 5, the packet loss rate Li in the link is input from the previous node 2 to the simultaneous connection flow number and usage rate management unit 14.
In addition, the quality degradation link usage rate estimation unit 16 sets a group (Nk, ρk) in a quality degradation state where ρk> ρ_1 and the average simultaneous connection flow number Nk is Nk> ρk × (R × (1 + ε)). Instead of extracting as a set, the packet loss rate Lk> L1 with respect to a predetermined threshold value L1, and the average simultaneous connection flow number Nk with respect to the predetermined threshold value ε is Nk> ρk × (R × ( 1 + ε)) is extracted as a set of quality degradation states (Nk, ρk), and quality degradation starts by the method of the first embodiment or the second embodiment using the extracted set (Nk, ρk). The link usage rate is calculated.

［実施例６］
本実施例は、前述の実施例５において、使用率当たりの同時接続フロー数算出部１５が、前記ｎ個の測定値の組み合わせ（Ｎｉ，ρｉ）のうち、予め定めた閾値ρ＿０に対して、ρｊ＜ρ＿０となる測定値（Ｎｊ，ρｊ）を用いて、平均リンク使用率当たりの平均同時接続フロー数Ｒを算出する代わりに、予め定めた閾値Ｌ０に対してＬｊ＜Ｌ０の場合の測定値（Ｎｊ，ρｊ）を用いて平均リンク使用率当たりの平均同時接続フロー数Ｒを算出し、当該平均リンク使用率当たりの平均同時接続フロー数Ｒを用いて、前述実施例１または実施例２の方法により、品質劣化が開始するリンク使用率を算出する。 [Example 6]
In this embodiment, in the above-described embodiment 5, the simultaneous connection flow number calculation unit 15 per usage rate uses a predetermined threshold ρ_0 among the combinations of the n measurement values (Ni, ρi). Instead of calculating the average simultaneous connection flow number R per average link usage rate using the measurement values (Nj, ρj) that satisfy ρj <ρ_0, the measurement values when Lj <L0 with respect to a predetermined threshold L0 (Nj, ρj) is used to calculate the average simultaneous connection flow number R per average link usage rate, and the average simultaneous connection flow number R per average link usage rate is used to calculate the average concurrent connection flow number R. The link usage rate at which quality degradation starts is calculated by the method.

［実施例７］
本実施例でも、図５に点線で示すように、同時接続フロー数および使用率管理部１４に前段ノード２から、前記リンクにおけるパケット損失率Ｌｉが入力される。
また、使用率当たりの同時接続フロー数算出部１５が、前記ｎ個の測定値の組み合わせ（Ｎｉ，ρｉ）のうち、予め定めた閾値ρ＿０に対して、ρｊ＜ρ＿０となる測定値（Ｎｊ，ρｊ）を用いて、平均リンク使用率当たりの平均同時接続フロー数Ｒを算出する代わりに、予め定めた閾値Ｌ０に対してＬｊ＜Ｌ０の場合の測定値（Ｎｊ，ρｊ）を用いて、平均リンク使用率当たりの平均同時接続フロー数Ｒを算出し、当該平均リンク使用率当たりの平均同時接続フロー数Ｒを用いて、前述実施例１から実施例４のいずれかの方法により、品質劣化が開始するリンク使用率を算出する。
[Example 7]
Also in this embodiment, as indicated by a dotted line in FIG. 5, the packet loss rate Li in the link is input from the preceding node 2 to the simultaneous connection flow number and usage rate management unit 14.
In addition, the number of simultaneously connected flows per usage rate calculation unit 15 determines a measurement value (Nj, ρj <ρ_0) with respect to a predetermined threshold ρ_0 among the combination of the n measurement values (Ni, ρi). Instead of calculating the average number of simultaneous connections R per average link usage rate using ρj), using the measured value (Nj, ρj) when Lj <L0 with respect to a predetermined threshold L0, the average The average simultaneous connection flow number R per link usage rate is calculated, and the average simultaneous connection flow number R per average link usage rate is used to determine the quality degradation by any of the methods in the first to fourth embodiments. Calculate the starting link utilization.

なお、前述の説明において、品質劣化リンク使用率推定装置１はコンピュータに実行させることも可能であり、その場合に、前述の品質劣化リンク使用率推定方法は、コンピュータ内のハードディスクなどに格納されるプログラムを、コンピュータが実行することにより行われる。このプログラムは、ＣＤ−ＲＯＭなどの記録媒体、あるいは、ネットワークを介したダウンロードにより供給される。
以上説明したように、本実施例によれば、観測が簡易な同時接続フロー数と使用率という値のみからそれらの関係を算出することにより、当該リンクにおいて品質劣化が開始するリンク使用率を推定する方法及びその装置を提供することができる。
そのリンク使用率を用いれば、それをρ^＊とおき、当該リンクに加わると予想される最大負荷をＬｍａｘとおけば、通信品質を維持するのに必要な帯域をＬｍａｘ／ρ^＊により算出可能となり、また常にフロー数を測定しなくてもそれをリンク使用率の基準値として品質管理することも可能となる。
以上、本発明者によってなされた発明を、前記実施の形態に基づき具体的に説明したが、本発明は、前記実施の形態に限定されるものではなく、その要旨を逸脱しない範囲において種々変更可能であることは勿論である。 In the above description, the quality degradation link usage rate estimation apparatus 1 can be executed by a computer. In this case, the quality degradation link usage rate estimation method is stored in a hard disk or the like in the computer. The program is executed by the computer executing. This program is supplied by a recording medium such as a CD-ROM or downloaded via a network.
As described above, according to the present embodiment, the link usage rate at which quality degradation starts in the link is estimated by calculating the relationship only from the values of the number of simultaneous connection flows and the usage rate that are easy to observe. And a device for the same can be provided.
If the link usage rate is used, it is set as ρ ^* , and if the maximum load expected to be applied to the link is set as Lmax, the bandwidth necessary for maintaining the communication quality can be calculated by Lmax / ρ ^* . In addition, even if the number of flows is not always measured, it is possible to perform quality control as a reference value for the link usage rate.
Although the invention made by the present inventor has been specifically described based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. Of course.

リンク使用率に対して同時接続フロー数、平均ファイル転送時間の関係を示したグラフである。It is the graph which showed the relationship between the number of simultaneous connection flows and average file transfer time with respect to a link usage rate. 通信帯域を増設した後における、同時接続フロー数、平均ファイル転送時間の関係を示したグラフである。6 is a graph showing the relationship between the number of simultaneous connection flows and the average file transfer time after adding a communication band. 同時接続フロー数とリンク使用率をシミュレーション実験により実測した結果をプロットしたグラフである。It is the graph which plotted the result of having actually measured the number of simultaneous connection flows and the link usage rate by the simulation experiment. 本発明の品質劣化リンク使用率推定装置が適用されるＩＰネットワークの基本構成の一例を示す構成図である。It is a block diagram which shows an example of the basic composition of the IP network to which the quality degradation link usage rate estimation apparatus of this invention is applied. 本発明の実施例１の品質劣化リンク使用率推定装置の一例の概略構成を示すブロック図である。It is a block diagram which shows schematic structure of an example of the quality degradation link usage rate estimation apparatus of Example 1 of this invention.

Explanation of symbols

１品質劣化リンク使用率推定装置
２，３ノード
１１パケットヘッダ解析部
１２リンク使用率算出部
１３同時接続フロー数算出部
１４同時接続フロー数および使用率管理部
１５使用率当たりの同時接続フロー数算出部
１６品質劣化リンク使用率推定部 DESCRIPTION OF SYMBOLS 1 Quality degradation link usage rate estimation apparatus 2,3 Node 11 Packet header analysis part 12 Link usage rate calculation part 13 Simultaneous connection flow number calculation part 14 Simultaneous connection flow number and usage rate management part 15 Calculation of the number of simultaneous connection flows per usage rate Part 16 Quality degradation link usage rate estimation part

Claims

In the quality degradation link usage rate estimation method for estimating the link usage rate at which the communication quality of the user flow via a certain link in the communication network starts to deteriorate,
Measure the average simultaneous connection number Ni of flows passing through the link in a predetermined time interval t0,
Measure the average usage rate ρi (i = 1, ..., n) of the link,
Of these n combinations of measurement values (Ni, ρi), the average simultaneous connection per average link usage rate using the measurement value (Nj, ρj) satisfying ρj <ρ_0 with respect to a predetermined threshold ρ_0. Calculate the number of flows R,
Using the section width delta _[rho against predetermined link utilization, the interval _{[(j-1) Δ ρ} , jΔ ρ] extracts belongs (Ni, .rho.i) to, and the number of sets and _{n j,}
Extracted (Ni, ρi) section using _{[(j-1) Δ ρ} , jΔ ρ] in E [N] and a linear function E represents the relationship ρ [N] = αj + βj × coefficient [rho .alpha.j, .beta.j the calculated by the least squares method, which was performed for j = 1~1 / Δ _ρ,
For _{ρ in} the interval [(j−1) Δ _ρ , jΔ _ρ ], the measured average simultaneous connection flow number N is average E [N | ρ] = αj + βj × ρ, variance V [N | ρ] = [ Suppose that it follows a normal distribution of Σ {Ni− (αj + βj × ρ)} ² / (n _j −2)], and uses a predetermined threshold ε, and a probability P [N> (1 + ε) × R × ρi for ρi | Ρi] is calculated using a normal distribution with mean E [N | ρi] and variance = V [N | ρi], and this is performed for i = 1 to n,
ρk <a ρ_th set (Nk, ρk) number was used as a n 'of, a set of index k at that time the _S ρ _ _th, the quality deterioration of d under the condition that ρk <ρ_th, d = Σ _{kεSp_th} P [N> (1 + ε) × R × ρk | ρk] / n ′
The same procedure is performed for various ρ_ths, and the maximum ρ_th such that the quality degradation level d is equal to or less than a predetermined degradation level target value δ is estimated as the link usage rate at which the quality degradation starts. quality deterioration link utilization estimation how to.

In the quality degradation link usage rate estimation method for estimating the link usage rate at which the communication quality of the user flow via a certain link in the communication network starts to deteriorate,
Measure the average simultaneous connection number Ni of flows passing through the link in a predetermined time interval t0,
Measure the average usage rate ρi (i = 1, ..., n) of the link,
Of these n combinations of measurement values (Ni, ρi), the average simultaneous connection per average link usage rate using the measurement value (Nj, ρj) satisfying ρj <ρ_0 with respect to a predetermined threshold ρ_0. Calculate the number of flows R,
Using the section width delta _[rho against predetermined link utilization, the interval _{[(j-1) Δ ρ} , jΔ ρ] extracts belongs (Ni, .rho.i) to,
Extracted (Ni, ρi) section using _{[(j-1) Δ ρ} , jΔ ρ] in E [N] and a linear function E represents the relationship ρ [N] = αj + βj × coefficient [rho .alpha.j, .beta.j the calculated by the least squares method, which was performed for j = 1~1 / Δ _ρ,
For _{ρ in} the interval [(j−1) Δ _ρ , jΔ _ρ ], the measured average simultaneous connection flow number N is average E [N | ρ] = αj + βj × ρ, variance V [N | ρ] = [ and follows a normal distribution of Σ {Ni- (αj + βj × ρ)} 2 / (n j -2)],
Given a probability density function g _ρ _ _th (ρ) for ρ under the condition of ρ <ρ_th, the quality degradation degree d at ρ <ρ_th is calculated by the following equation (1):
The same procedure is performed for various ρ_ths, and the maximum ρ_th such that the quality degradation level d is equal to or less than a predetermined degradation level target value δ is estimated as the link usage rate at which the quality degradation starts. quality deterioration link utilization estimation method shall be the.
[Expression 1] d = ∫P [N> (1 + ε) × R × ρ | ρ] × g _{ρ —} _th (ρ) dρ
... (1)

In the quality degradation link usage rate estimation method for estimating the link usage rate at which the communication quality of the user flow via a certain link in the communication network starts to deteriorate,
Measure the average simultaneous connection number Ni of flows passing through the link in a predetermined time interval t0,
Measure the average usage rate ρi (i = 1, ..., n) of the link,
Of these n combinations of measurement values (Ni, ρi), the average simultaneous connection per average link usage rate using the measurement value (Nj, ρj) satisfying ρj <ρ_0 with respect to a predetermined threshold ρ_0. Calculate the number of flows R,
Using n combinations (Ni, ρi), R, and predetermined threshold values ε and ρ_1, a set (Nk, ρk) satisfying ρk <ρ_th is extracted for a certain ρ_th, and the number of sets is set to n 'age,
The packet loss rate Li in the link is also measured at the same time,
Packet loss rate Lk> L1 against a threshold L1 which defines Me pre and average concurrent flow number Nk against a threshold epsilon a predetermined is, Nk> ρk × (R × (1 + ε)) and becomes a set (Nk , Ρk) as “a set of quality degradation conditions under the condition of ρk <ρ_th”, and the number of sets is m,
d = m / n ′ is defined as the degree of quality degradation under the condition of ρk <ρ_th, and the same procedure is performed for various ρ_th.
Quality degradation degree d is a predetermined maximum ρ_th such that less degradation level target value [delta], quality deterioration link utilization estimation method and estimating a link utilization quality deterioration begins.

The measurement of the n measurement values (Ni, ρi) (i = 1,..., N) is performed M times,
For the I-th data set (I = 1 to M), the value of the quality degradation degree d is calculated, and the result is d (I).
Using {d (1), d (2),... D (M)}, the arithmetic average d_ave and the one-sided x% confidence interval d_x are obtained, and d_ave + d_x is equal to or less than the predetermined degradation degree target value δ. The quality degradation link usage rate estimation method according to claim 3 , wherein the maximum ρ_th is estimated as a link usage rate at which quality degradation starts.

Of the n measurement value combinations (Ni, ρi), an average simultaneous connection per average link usage rate using a measurement value (Nj, ρj) that satisfies ρj <ρ_0 with respect to a predetermined threshold ρ_0. Instead of calculating the flow number R, the average simultaneous connection flow number R per average link usage rate is calculated using the measured value (Nj, ρj) when Lj <L0 with respect to the predetermined threshold L0, The method for estimating a degraded link usage rate according to claim 3 or 4 , wherein a link usage rate at which quality degradation starts is estimated using an average number of simultaneous connection flows R per average link usage rate.

Measure the packet loss rate Li in the link,
Of the n measurement value combinations (Ni, ρi), an average simultaneous connection per average link usage rate using a measurement value (Nj, ρj) that satisfies ρj <ρ_0 with respect to a predetermined threshold ρ_0. Instead of calculating the flow number R, the average simultaneous connection flow number R per average link usage rate is calculated using the measured value (Nj, ρj) when Lj <L0 with respect to the predetermined threshold value L0. The quality degradation link according to any one of claims 1 to 5, wherein a link usage rate at which quality degradation starts is estimated using the average number of simultaneous connection flows R per said average link usage rate. Usage estimation method.

In a quality degradation link usage rate estimation device that estimates a link usage rate at which the communication quality of a user flow via a certain link starts to degrade in a communication network,
Means 1 for measuring an average simultaneous connection number Ni of flows passing through the link in a predetermined time interval t0, and measuring an average usage rate ρi (i = 1,..., N) of the link;
Of the n measurement value combinations (Ni, ρi), an average simultaneous connection per average link usage rate using a measurement value (Nj, ρj) that satisfies ρj <ρ_0 with respect to a predetermined threshold ρ_0. The flow number R is calculated, the section width Δ _ρ with respect to the predetermined link usage rate is used, (Ni, ρi) belonging to the section [(j−1) Δ _ρ , jΔ _ρ ] is extracted, and the number of sets is expressed as nj and then was extracted (Ni, .rho.i) section using _{[(j-1) Δ ρ} , jΔ ρ] in E [N] and a linear function E represents the relationship ρ [N] = αj + βj × coefficient [rho .alpha.j , calculated by the least squares method .beta.j, which was carried out for j = 1~1 / Δ _ρ, the interval _{[(j-1) Δ ρ} , jΔ ρ] to [rho in average concurrent flow number N to be measured Mean E [N | ρ] = αj + βj × ρ, variance V [N | ρ] = [Σ {Ni− (αj + βj × ρ) ² / _(n j -2)] and follows a normal distribution of using a threshold epsilon a predetermined probability with respect to ρi P [N> (1 + ε) × R × ρi | ρi] Average E [N | ρi ], Using a normal distribution of variance = V [N | ρi], this is performed for i = 1 to n, and the number of pairs (Nk, ρk) where ρk <ρ_th is n ′, The set of indexes k at that time is S _{ρ_th,} and the quality degradation degree d under the condition of ρk <ρ_th is defined as d = Σ _{kεSp_th} P [N> (1 + ε) × R × ρk | ρk] / n ′ The same procedure is performed for various ρ_ths, and the maximum ρ_th such that the quality degradation level d is equal to or less than the predetermined degradation level target value δ is estimated as the link usage rate at which the quality degradation starts. quality-degraded link utilization estimator you anda means 2.

In a quality degradation link usage rate estimation device that estimates a link usage rate at which the communication quality of a user flow via a certain link starts to degrade in a communication network,
Means 1 for measuring an average simultaneous connection number Ni of flows passing through the link in a predetermined time interval t0, and measuring an average usage rate ρi (i = 1,..., N) of the link;
Of the n measurement value combinations (Ni, ρi), an average simultaneous connection per average link usage rate using a measurement value (Nj, ρj) that satisfies ρj <ρ_0 with respect to a predetermined threshold ρ_0. It calculates the number of flows R, using the interval width delta _[rho against predetermined link utilization, the interval _{[(j-1) Δ ρ} , jΔ ρ] extracts belongs (Ni, .rho.i), the extracted (Ni interval using ρi) [(j-1) Δ ρ, jΔ ρ] E in [N] and a linear function E represents the relationship ρ [N] = αj + βj × coefficient [rho .alpha.j, by the least squares method .beta.j calculated, which was carried out for j = 1~1 / Δ _ρ, the interval _{[(j-1) Δ ρ} , jΔ ρ] to [rho in average concurrent flow number N to be measured, the average E [N | ρ] = αj + βj × ρ , variance V [n | ρ] = [ Σ {Ni- (αj + βj × ρ)} 2 / (n j -2) Of a normally distributed, [rho <giving _ _{th ([rho)} the probability density function g _[rho against [rho under the condition that ρ_th, ρ <a quality deterioration degree d in Ro_th, calculated by the following equation (2), the same procedure various Ro_th, relative to the maximum Ro_th as quality deterioration degree d is equal to or less than δ predetermined deterioration level target value, and means (2) for estimating a link utilization quality degradation begins quality-degraded link utilization estimator you comprising: a.
[Equation 2]
d = ∫P [N> (1 + ε) × R × ρ | ρ] × g _{ρ —} _th (ρ) dρ
(2)

In a quality degradation link usage rate estimation device that estimates a link usage rate at which the communication quality of a user flow via a certain link starts to degrade in a communication network,
Means 1 for measuring an average simultaneous connection number Ni of flows passing through the link in a predetermined time interval t0, and measuring an average usage rate ρi (i = 1,..., N) of the link;
A packet loss rate Li in the link is input from the outside, and among the n combinations of measured values (Ni, ρi), measured values (Nj, ρj) satisfying ρj <ρ_0 with respect to a predetermined threshold ρ_0. Is used to calculate the average number of simultaneous connection flows R per average link usage rate, and to the predetermined threshold L1 using n combinations (Ni, ρi), R, and predetermined thresholds ε and ρ_1. On the other hand, a group (Nk, ρk) in which the packet loss rate Lk> L1 and the average simultaneous connection flow number Nk with respect to a predetermined threshold ε is Nk> ρk × (R × (1 + ε)) is expressed as “ρk <"As a set of quality degradation states under the condition of ρ_th", the number of the sets is m, d = m / n 'is the degree of quality degradation under the condition of ρk <ρ_th, and various similar procedures are performed. Ρ_th, and the quality degradation level d is The maximum ρ_th such that predetermined deterioration degree target value δ less, quality deterioration link utilization estimator you anda said means 2 for estimating the link utilization quality deterioration begins.

The means 1 performs the measurement of the n measurement values (Ni, ρi) (i = 1,..., N) M times,
The means 2 calculates the value of the quality degradation degree d for the I-th data set (I = 1 to M), and sets the result as d (I), {d (1), d (2) ,...,... D (M)} to obtain the arithmetic mean d_ave and the one-sided x% confidence interval d_x, and the maximum ρ_th such that d_ave + d_x is equal to or less than the predetermined degradation degree target value δ The quality degradation link usage rate estimation apparatus according to claim 9 , wherein the quality degradation link usage rate estimation apparatus estimates the link usage rate to be started.

The means 2 uses the measured values (Nj, ρj) satisfying ρj <ρ_0 with respect to a predetermined threshold ρ_0 among the combinations of the n measured values (Ni, ρi), and the average link usage rate. Instead of calculating the average number of simultaneous connection flows R per unit, the average number of simultaneous connection flows R per average link usage rate using a measured value (Nj, ρj) when Lj <L0 with respect to a predetermined threshold L0 The link utilization rate at which quality degradation starts is estimated using the average number of simultaneous connection flows R per the average link utilization rate, and the quality degraded link usage according to claim 9 or 10 , Rate estimation device.

The means 2 receives a packet loss rate Li in the link from the outside,
The means 2 uses the measured values (Nj, ρj) satisfying ρj <ρ_0 with respect to a predetermined threshold ρ_0 among the combinations of the n measured values (Ni, ρi), and the average link usage rate. Instead of calculating the average number of simultaneous connection flows R per unit, the average number of simultaneous connection flows per average link usage rate using a measured value (Nj, ρj) when Lj <L0 with respect to a predetermined threshold L0 calculates R, in any one of claims 7 to 11, characterized in that for estimating the link utilization to initiate the quality deterioration using the average concurrent flow rate R per the average link utilization The quality degradation link usage rate estimation apparatus described.