JP3870097B2 - Line remedy method and network using the same - Google Patents

Description

として定義される。
【００１８】
本パラメータを用いてネットワーク構成における救済動作を説明する。まず当初のネットワークは、３つの回線が定義されている。各回線には、重要度が付与される。例えば、
回線Ａ重要度Ｇ（Ａ）＝１００
回線Ｂ重要度Ｇ（Ｂ）＝５０
回線Ｃ重要度Ｇ（Ｃ）＝３３
のように、救済すべき順番（上記では、順番は上から１，２，３）の逆数に応じた値が回線の重要性の値として付与される。重要度は、これとは別に、トラフィック量を重要とする場合には、回線の速度に比例した、
回線Ａ重要度Ｇ（Ａ）＝２，５００
回線Ｂ重要度Ｇ（Ｂ）＝１５０
回線Ｃ重要度Ｇ（Ｃ）＝１５０
のようにしてもよい。この場合、正常時における救済度は、

となる。
【００１９】
故障ケース２における救済度Ｐ2を考える。故障ケース２における救済パターンは２つあり、これを図２に示す。図２ａがパターン１、図２ｂがパターン２を示す。それぞれの救済パターンにおける救済度は、
Ｐ2（１）＝ΣＧ（ｉ）＝１５０＋１５０＝３００
Ｐ2（２）＝ΣＧ（ｉ）＝２，５００
であり、同じく救済率Ｓ2は、
Ｓ2（１）＝３００／２，８００＝１０．７％
Ｓ2（２）＝２，５００／２，８００＝８９．３％
となり、パターン２の方が救済率が高い救済方法であることが分かる。
【００２０】
次に，同様のネットワーク構成において、回線の速度が全て等しく（例えば１５０Ｍｂｉｔ／ｓ）、回線の重要度が同等であると場合を想定する。この場合、各回線の重要度は、重要性から、
回線Ａ重要度Ｇ（Ａ）＝１０
回線Ｂ重要度Ｇ（Ｂ）＝１０
回線Ｃ重要度Ｇ（Ｃ）＝１０
のように設定される。この場合も同様に故障ケース２を考えると、救済パターン１、２の救済率はそれぞれ、
Ｓ2（１）＝２０／３０＝６６．７％
Ｓ2（２）＝１０／３０＝３３．３％
となり、救済パターン１を選定すべきと判断される。
【００２１】
次に、回線Ａが他の回線Ｂ，Ｃに対して重要であると判断される場合を考える。このとき、各回線の重要度は、
回線Ａ重要度Ｇ（Ａ）＝５０
回線Ｂ重要度Ｇ（Ｂ）＝１０
回線Ｃ重要度Ｇ（Ｃ）＝１０
のように設定される。この場合も同様に故障ケース２を考えると、救済パターン１、２の救済率はそれぞれ、
Ｓ2（１）＝２０／７０＝２８．６％
Ｓ2（２）＝１０／３０＝７１．４％
となり、救済後の回線数は少なくなるが、それでも重要な回線である回線Ａを救済する救済パターン２を選択すべきであると判断される。
【００２２】
以上説明した様に、回線に重要度を付与し、それに基づく救済パターンを検討することより、様々な故障ケースにおいて、残った設備を最大限に有効利用することを簡易に実現することができる。
【００２３】
以上のように、本発明においては、ある故障ケースkにおいて、あらゆる救済パターンＲn（nは故障ケースkにおける全ての救済パターン数）の中で救済率が最も高い救済パターンＲm（mはnの一要素）を選定することにより、救済方法を決定する。つまり、Ｒm | Ｓk（Ｒm）がＳk（Ｒn）の中で最大値となるＲmを選定するアルゴリズムに他ならない。
【００２４】
次に、波長多重技術と光クロスコネクト技術により光回線を設定するネットワークに本発明の回線救済方法を適用した実施形態の例を図３に示す。ネットワークは、複数のノード装置１（１a〜１e）を伝送路２（２ab，２bc，２cd，２db，２de，２ea）で接続してなる。
【００２５】
ノード装置１は、複数の光パス３（３-1，３-2，…，３-p、pは正の整数）に対してその行先に応じて交換を行なう光クロスコネクト装置（ＯＸＣ：Optical Cross Connect）４と交換後の光パスを多重化して伝送路２に送出する波長多重装置（ＷＤＭ：Wavelength Division Multiplexing）５からなる。また、波長多重装置５は、接続先のノード装置１からの多重化された光パスを個々に分け、光クロスコネクト装置４に供給する。光クロスコネクト装置４は、供給された光パスに対しても交換を行なう。伝送路２は、光ファイバにより構成される。なお、光パス３には、例えば、１０Ｇｂ／ｓ、２．４Ｇｂ／ｓ、６００Ｍｂ／ｓ、１５０Ｍｂ／ｓ等の種々の伝送速度のものがあり、伝送する単一或いは複数の信号を搭載している。
【００２６】
図３のネットワークにおいて、ノード装置１aへの光パス３-q（qはp以下の正の整数）の行先がノード装置１cである場合、例えばノード装置１bを経由するルートに光回線が設定される。或いはネットワークの状況によっては、ノード装置１e及びノード装置１dを経由するルートに光回線が設定されたりする。このような光回線の設定の制御が後述するように監視制御センタ１６によって行なわれる。
【００２７】
次に、光クロスコネクト装置４の一般的な構成を図４に示す。装置４は、交換接続動作を行なう光スイッチ部１３のほか、光パス３に接続されるＵＮＩ（User-Network Interface）インタフェース部１１と、ノード装置Ｎ間の接続に使用されるＮＮＩ（Network Node Interface）インタフェース部１２の２種類のインタフェースを有する。
【００２８】
ＵＮＩインタフェース部１１には、ＳＤＨ（Synchronous Digital Hierarchy）伝送装置、ＡＴＭ（Asynchronous Transfer Mode）伝送装置、高速ＩＰ（Internet Protocol）ルータ装置などの光インタフェースを有する装置が接続される。ノード装置Ｎ間を接続するＮＮＩインタフェース部１２は、波長多重装置５と光スイッチ部１３との間に配置される。波長多重装置５は、ＮＮＩインタフェース部１２からの多数の光パス（光信号）を波長で多重化して１本の光ファイバに送出する。伝送路２は、複数の光ファイバが束ねて構成される。光ファイバの伝送損失が極めて低いため長距離伝送が可能であり、波長多重と相俟って他の多くのノード装置との接続が可能となり、ネットワークの拡張が可能となる。
【００２９】
また、光クロスコネクト装置４において交換接続動作を行なう光スイッチ部１３は、光マトリックススイッチを備え、各インタフェースからの回線を自由に接続変更する機能（クロスコネクト機能）を有し、更に、特に障害発生時における光回線の接続変更を行なう機能を有する。そして、その交換接続の指示は、制御部１４にて行なわれる。
【００３０】
制御部１４は、全てのノード装置即ちネットワーク全体を監視制御する監視制御センタ１６と接続する通信ライン１５を有しており、監視制御センタ１６との通信により、実際の光回線の設定、並びに障害発生時の復旧処理が行なわれる。
【００３１】
監視制御センタ１６の構成を図５に示す。監視制御センタ１６は、各光クロスコネクト装置４の制御部１４との通信を行なう通信回路２１、中央処理装置（ＣＰＵ）２２、各種データを格納するメモリ２３、外部とのインタフェースを司るマンマシンインタフェース２４を有する入出力制御回路２５、プログラムを格納するプログラムメモリ２６、及びこれの各部を接続する内部バス２７から構成される。特にマンマシンインタフェース２４は、表示器、命令を入力するキーボードなどより構成される。また、プログラムメモリ２６には、光回線制御プログラム２８が内蔵されており、これによりネットワーク全体としての光回線の接続制御、或いは、障害発生時の光回線の接続変更による救済などが行なわれる。
【００３２】
このようなネットワーク監視制御は、各光クロスコネクト装置４に搭載される制御部１４と、監視制御センタ１６の全体としての動作として行なわれる。そして監視制御センタ１６からの光回線設定の指示、或いは光クロスコネクト装置４を有する各ノード装置１からの障害情報の監視制御センタ１６への通知が通信ライン１５を介して行なわれる。
【００３３】
以上の光ネットワークにおいて実行する、あらゆる救済パターンＲnの中で救済率が最も高い救済パターンＲmを選定する本発明のアルゴリズムを図６を用いて説明する。本アルゴリズムに基づくネットワーク監視制御が監視制御センタ１６によって一括して行なわれる。そして、本アルゴリズムは、監視制御センタ１６のプログラムメモリ２６に搭載された光回線制御プログラム２８として動作する。
【００３４】
なお、このような一括制御とは別に、ネットワーク監視制御の機能を各光クロスコネクト装置４の制御部１４に分散して配備することも可能である。一括、分散のいずれでも本アルゴリズムの一般性は失われない。
【００３５】
まず、本プログラムは、各光クロスコネクト装置４からの通信ライン１５を介しての障害情報の入力を契機に起動される。まず、ネットワーク全体として設定されている光回線の集合（ｊ）とそれぞれの重要度Ｇ（ｊ）を初期構成として入力する（ステップＳ１）。次に、本重要度の総和として、初期救済度ＰO（０）を算出する（ステップＳ２）。次に、入力された故障情報を前提として、故障パターンを洗い出してリスト形式とする（ステップＳ３）。故障パターンに対応した回線を救済する全てのパターンを洗い出してリスト（Ｒ）とする（ステップＳ４）。ここで、初期値として救済率Ｓmを０とする（ステップＳ５）。次に救済パターン（Ｒn）をリストの最初から順次引き出して（ステップＳ６）、それに対応する救済率Ｓ（Ｒn）を算出して（ステップＳ７）、Ｓ（Ｒn）をＳmと比較する（ステップＳ８）。Ｓmより大きければＳmをＳ（Ｒn）とし（ステップＳ９）、そうでなければステップＳ９を実行せず、次の救済パターンにプールする（ステップＳ１０）。これにより、最大の救済率を有する救済パターンが検索される。
【００３６】
以上、本実施形態により、障害が発生した回線を救済する際に回線の重要性を考慮することによって救済効果を高めた回線救済方法を実現し、同時に、そのような救済方法を採用することによって信頼性を向上させたネットワークを実現することができる。
【００３７】
なお、ここでは、最も簡単なネットワーク構成例で示したが、さらに大きなネットワーク構成、或いは、ノード装置間の回線が複数存在し、当初の回線数がさらに多い場合においても全く同様の手法を適用することができる。
【００３８】
【発明の効果】
本発明によれば、複雑なネットワーク構成において、障害が発生した場合に残された設備を最大限に有効利用する最も効果的な回線の救済パターンを選定することが可能になり、それによってネットワークの信頼性を最大限確保することができる。
【図面の簡単な説明】
【図１】本発明に係る回線救済方法の発明の実施の形態を説明するための図。
【図２】本発明の効果を示すための救済パターンの例を説明するための図。
【図３】本発明の回線救済方法を適用したネットワークの例を説明するための構成図。
【図４】図３に示したネットワークにおける光クロスコネクト装置を説明するための構成図。
【図５】図３に示したネットワークにおける監視制御センタを説明するための構成図。
【図６】本発明の回線救済方法のアルゴリズムを説明するためのフローチャート図。
【図７】従来の回線救済方法を説明するための図。
【符号の説明】
１…ノード装置、２…伝送路、３…光パス、４…光クロスコネクト装置、５…波長多重装置、１１…ＵＮＩインタフェース部、１２…ＮＮＩインタフェース部、１３…光スイッチ部、１４…制御部、１５…通信ライン、１６…監視制御センタ、２１…通信回路、２２…ＣＰＵ、２３…メモリ、２４…マンマシンインタフェース、２５…入出力回路、２６…プログラムメモリ、２７…内部バス、２８…光回線設定制御プログラム。[0001]
BACKGROUND OF THE INVENTION
In the present invention, in a mesh-type network in which a plurality of node devices are connected to each other via a transmission line and a line is arbitrarily set, another line is set when a failure occurs in the transmission line or the node device. The present invention relates to a method for relieving a failed line.
[0002]
[Prior art]
In recent years, with the progress of the information industry including the Internet, development of an ultra-wideband network for setting an optical line by wavelength multiplexing technology and optical cross-connect technology has been actively promoted. In such a network, an example of a method for relieving a line in the event of a failure such as a line failure is published by Morgan Kaufmann (USA) 2000, Rajif Ramanswasumi, Kumar N. "Optical Networks -A Practical Perspective-", co-authored by Rajiv Ramanswasmi, Kumar n. Sivarajan, pages 442-446. The literature describes the idea that if a failure occurs in one of the transmission lines in a network configuration, the line that has been affected by the failure and the signal is abnormal is changed to a line of a different path and relieved. ing. This is based on the premise that the line affected by the failure is remedied, and there is no mention of the case where another failure occurs at the same time and the detour line cannot be set.
[0003]
A conventional line repair method based on the above-described repair method will be described with reference to FIG. In the network configuration example shown in FIG. 7, four node devices (N) 1a to 1d are connected by five transmission lines 2ab, 2bc, 2bd, 2cd, and 2ca. In the case of an optical network, the node device 1 is usually composed of an optical cross-connect device that performs exchange processing of a plurality of signals and a wavelength multiplexing device that multiplexes signals after the exchange. In general, a plurality of lines are conceivable between the node apparatuses 1, but here, for the purpose of explaining the principle, it is assumed that all the lines between the node apparatuses 1 are one. Here, it is assumed that the line A is set for the route between the node devices 1b and 1c, the line C is set for the route between the node devices 1a and 1b, and the line B is set for the route between the node devices 1a and 1c.
[0004]
In this network, when a failure 1 occurs in the route between the node devices 1b and 1c and the line A is disconnected (FIG. 7a), the route of the line A is changed to a line via the node device 1d which is an empty line. Then, it is relieved (FIG. 7b). Here, it is assumed that a failure 2 further occurs in the route between the node devices 1c and 1d. In this case, line A is disconnected because there is no longer a backup route for line A.
[0005]
Here, it is assumed that the transmission rates of the lines A, B, and C are 2.5 Gbit / s, 150 Mbit / s, and 150 Mbit / s, respectively. In this case, while the total traffic amount at normal time is 2.8 Gbit / s, the total traffic amount is reduced to 0.3 Gbit / s due to failures 1 and 2.
[0006]
On the other hand, the normal switching system has a configuration of “1 + 1 switching” in which one spare is prepared for one active line, and “1: N switching” in which one spare is prepared for N working lines. G. ITU-T (International telecommunication Union) recommendation. 783 as an international standard. In particular, in “1: N switching”, a concept of switching called extra traffic is shown. “1: N switching” is a switching method for switching to the standby system when any one of N fails, but when all of the active systems are normal, the standby system is switched to the normal operation line. It is intended to be used as Of course, this extra traffic line cannot be used as an operation line if any of the working systems fails. Even in this standard, there is no mention of a remedy method in particular when a plurality of failures occur.
[0007]
[Problems to be solved by the invention]
In a network for setting an optical line, signals of various transmission rates are exchanged as described above. Therefore, there may be a difference of about 100 times as a traffic amount between a low-speed signal and a high-speed signal. Apart from this, there are cases where lines that cannot be handled in the same way as other lines, such as lines for defense, police, firefighting, and emergency, which take care of human lives, may be set. Such a line for transmitting a high-speed signal or a line for saving lives must be treated as having high importance. However, in the conventional line remedy method and switching method, the concept of the importance of such a line is out of sight.
[0008]
In the mesh type network in which a plurality of node devices shown in FIG. 7 are connected to each other, as described above, there is a method of switching a line affected by a failure such as a failure of a transmission path or a node device to an empty line. Taken. However, if a failure occurs and a free line is not found, even if the importance of the line is high, the line is naturally not repaired as unrepairable.
[0009]
An object of the present invention is to provide a line remedy method in which the remedy effect is enhanced by considering the importance of the line when the line in which the failure has occurred is remedied, and a highly reliable network employing such a method. There is.
[0010]
[Means for Solving the Problems]
The above-described problem of the present invention is achieved by relieving a line in which a failure has occurred by changing a switched connection to an empty route that is secured by deleting a normal line when there is no spare route to be used for a line in a disconnected state. Can be solved. Specifically, a parameter corresponding to the importance is assigned to the line, and relief is performed by determining the importance in every failure case. According to this remedy method, if a failure occurs on a high-priority line but there is no free space, the low-importance line that does not cause a failure is deleted, and then the high-priority line is allocated and relieved. The method is adopted. Therefore, relief is performed so that the overall importance is maximized even in various complex failure cases. For example, when the importance is represented by a transmission rate, the relief is performed so that the entire traffic amount is maximized.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the line repair method and apparatus according to the present invention will be described in more detail with reference to the embodiments of the present invention shown in the drawings.
[0012]
First, the principle of the present invention will be described with reference to FIG. In the network configuration example of FIG. 1, four node devices 1a to 1d are connected by five transmission lines 2ab, 2bc, 2bd, 2cd, and 2ca. In general, a plurality of lines are conceivable between the node apparatuses 1, but here, for the purpose of explaining the principle, it is assumed that all the lines between the node apparatuses 1 are one. Here, it is assumed that the line A is set for the route between the node devices 1b and 1c, the line C is set for the route between the node devices 1a and 1b, and the line B is set for the route between the node devices 1a and 1c. Assume that the transmission rates of the lines A, B, and C are 2.5 Gbit / s, 150 Mbit / s, and 150 Mbit / s, respectively. In this case, the total traffic amount at normal time is 2.8 Gbit / s.
[0013]
In this network, when the failure 1 occurs in the route between the node devices 1b and 1c and the line A is disconnected (FIG. 1a), the route of the line A is changed to a line passing through the node device 1d which is an empty line. To be rescued (FIG. 1b). Here, it is assumed that a failure 2 further occurs in the route between the node devices 1c and 1d. By this line relief method, it is determined that the line A is more important than both the lines B and C, the lines B and C are temporarily deleted, and the line A is routed by using the route via the node device 1a. Bail out (FIG. 1b). In this way, the line A is relieved, and the traffic amount of the entire network is secured at 2.5 Gbit / s.
[0014]
Here, the principle of the present repair method will be generally described. First, a line relief pattern is indicated by R. R includes all combinations of lines to be remedied for failure occurrence cases. A line rescue level P (R) for each individual pattern R is introduced.
[0015]
The line rescue level Pk (R) is defined as the sum of the importance levels of the lines rescued by the repair pattern R in the failure case k by the following equation:
Pk (R) = ΣG (i)
It becomes. In this equation, i represents all lines that are relieved by the relieving pattern R.
[0016]
In particular, when the normal case is indicated by a failure case k = 0 and the repair pattern at that time is indicated by R = 0, P0 (0) indicates the sum of importance of all lines originally possessed by the network.
P0 (0) = ΣG (j)
It becomes. In this expression, j represents all of the lines at the normal time.
[0017]
Further, a line rescue rate Sk (R) is introduced. The line repair rate Sk (R) is a ratio of the sum of importance after repair when the repair pattern R is repaired to the failure pattern k and the sum of importance of all lines held in the initial network. Yes,

Is defined as
[0018]
The relief operation in the network configuration will be described using this parameter. First, three lines are defined in the initial network. Importance is given to each line. For example,
Line A importance G (A) = 100
Line B Importance G (B) = 50
Line C Importance G (C) = 33
As described above, a value corresponding to the reciprocal of the order to be relieved (in the above, the order is 1, 2, 3 from the top) is given as the importance value of the line. Apart from this, the importance is proportional to the line speed when the traffic volume is important.
Line A importance G (A) = 2,500
Line B Importance G (B) = 150
Line C Importance G (C) = 150
It may be as follows. In this case, the salvage level at normal time is

It becomes.
[0019]
Consider the relief level P2 in failure case 2. There are two relief patterns in failure case 2, which are shown in FIG. 2a shows pattern 1 and FIG. The degree of relief in each relief pattern is
P2 (1) = ΣG (i) = 150 + 150 = 300
P2 (2) = ΣG (i) = 2500
Similarly, the relief rate S2 is
S2 (1) = 300 / 2,800 = 10.7%
S2 (2) = 2500 / 2,800 = 89.3%
Thus, it can be seen that pattern 2 is a relief method with a higher relief rate.
[0020]
Next, in the same network configuration, it is assumed that all the line speeds are equal (for example, 150 Mbit / s) and the importance of the lines is equal. In this case, the importance of each line depends on the importance.
Line A importance G (A) = 10
Line B importance G (B) = 10
Line C Importance G (C) = 10
It is set like this. Similarly in this case, considering failure case 2, the relief rates of relief patterns 1 and 2 are respectively
S2 (1) = 20/30 = 66.7%
S2 (2) = 10/30 = 33.3%
Thus, it is determined that the relief pattern 1 should be selected.
[0021]
Next, consider a case where the line A is determined to be important with respect to the other lines B and C. At this time, the importance of each line is
Line A Importance G (A) = 50
Line B importance G (B) = 10
Line C Importance G (C) = 10
It is set like this. Similarly in this case, considering failure case 2, the relief rates of relief patterns 1 and 2 are respectively
S2 (1) = 20/70 = 28.6%
S2 (2) = 10/30 = 71.4%
Thus, although the number of lines after the repair is reduced, it is still determined that the repair pattern 2 for repairing the line A, which is an important line, should be selected.
[0022]
As described above, by assigning importance to a line and examining a repair pattern based on the importance, it is possible to easily realize the maximum effective use of the remaining equipment in various failure cases.
[0023]
As described above, in the present invention, in a certain failure case k, the repair pattern Rm (m is one of n) having the highest repair rate among all the repair patterns Rn (n is the number of all repair patterns in the failure case k). The remedy method is determined by selecting the element. In other words, this is nothing but an algorithm for selecting Rm with the maximum value of Rm | Sk (Rm) in Sk (Rn).
[0024]
Next, FIG. 3 shows an example of an embodiment in which the line repair method of the present invention is applied to a network in which an optical line is set by wavelength multiplexing technology and optical cross-connect technology. The network is formed by connecting a plurality of node devices 1 (1a to 1e) through transmission lines 2 (2ab, 2bc, 2cd, 2db, 2de, 2ea).
[0025]
The node device 1 is an optical cross-connect device (OXC: Optical) that exchanges a plurality of optical paths 3 (3-1, 3-2,..., 3-p, p is a positive integer) according to the destination. It comprises a wavelength division multiplexing (WDM) 5 that multiplexes the optical path after exchange with the cross connect (4) 4 and sends it to the transmission line 2. Further, the wavelength multiplexing device 5 divides the multiplexed optical paths from the connection destination node device 1 individually and supplies them to the optical cross-connect device 4. The optical cross-connect device 4 also exchanges the supplied optical path. The transmission line 2 is constituted by an optical fiber. The optical path 3 has various transmission speeds such as 10 Gb / s, 2.4 Gb / s, 600 Mb / s, and 150 Mb / s, and is equipped with a single signal or a plurality of signals to be transmitted. Yes.
[0026]
In the network of FIG. 3, when the destination of the optical path 3-q (q is a positive integer less than or equal to p) to the node device 1a is the node device 1c, for example, an optical line is set for a route passing through the node device 1b. The Alternatively, depending on the network situation, an optical line may be set for a route passing through the node device 1e and the node device 1d. Such optical line setting control is performed by the supervisory control center 16 as will be described later.
[0027]
Next, a general configuration of the optical cross-connect device 4 is shown in FIG. In addition to the optical switch unit 13 that performs an exchange connection operation, the device 4 includes a user-network interface (UNI) interface unit 11 connected to the optical path 3 and a network node interface NNI used for connection between the node devices N. 2) The interface unit 12 has two types of interfaces.
[0028]
The UNI interface unit 11 is connected to a device having an optical interface such as an SDH (Synchronous Digital Hierarchy) transmission device, an ATM (Asynchronous Transfer Mode) transmission device, or a high-speed IP (Internet Protocol) router device. The NNI interface unit 12 that connects the node devices N is disposed between the wavelength multiplexing device 5 and the optical switch unit 13. The wavelength multiplexing device 5 multiplexes a number of optical paths (optical signals) from the NNI interface unit 12 with wavelengths, and sends them to a single optical fiber. The transmission path 2 is configured by bundling a plurality of optical fibers. Since the transmission loss of the optical fiber is extremely low, long-distance transmission is possible. In combination with wavelength multiplexing, connection with many other node devices is possible, and the network can be expanded.
[0029]
In addition, the optical switch unit 13 that performs the exchange connection operation in the optical cross-connect device 4 includes an optical matrix switch, and has a function (cross-connect function) for freely changing the connection from each interface. It has a function of changing the connection of an optical line at the time of occurrence. Then, the control unit 14 gives an instruction for the exchange connection.
[0030]
The control unit 14 includes a communication line 15 that is connected to a monitoring control center 16 that monitors and controls all node devices, that is, the entire network. Recovery processing at the time of occurrence is performed.
[0031]
The configuration of the monitoring control center 16 is shown in FIG. The supervisory control center 16 includes a communication circuit 21 that performs communication with the control unit 14 of each optical cross-connect device 4, a central processing unit (CPU) 22, a memory 23 that stores various data, and a man-machine interface that controls an interface with the outside. 24, an input / output control circuit 25, a program memory 26 for storing a program, and an internal bus 27 for connecting each part thereof. In particular, the man-machine interface 24 includes a display, a keyboard for inputting commands, and the like. In addition, the program memory 26 incorporates an optical line control program 28, whereby the optical network connection control as a whole network or the relief by changing the optical line connection when a failure occurs is performed.
[0032]
Such network supervisory control is performed as the operation of the control unit 14 and the supervisory control center 16 mounted on each optical cross-connect device 4 as a whole. Then, an optical line setting instruction from the supervisory control center 16 or failure information from each node device 1 having the optical cross-connect device 4 is sent to the supervisory control center 16 via the communication line 15.
[0033]
The algorithm of the present invention for selecting the repair pattern Rm having the highest repair rate among all the repair patterns Rn executed in the above optical network will be described with reference to FIG. Network monitoring control based on this algorithm is performed collectively by the monitoring control center 16. The algorithm operates as an optical line control program 28 installed in the program memory 26 of the supervisory control center 16.
[0034]
In addition to such collective control, the network monitoring control function can be distributed and deployed in the control unit 14 of each optical cross-connect device 4. The generality of this algorithm is not lost in either batch or distribution.
[0035]
First, this program is activated upon input of failure information from each optical cross-connect device 4 via the communication line 15. First, a set (j) of optical lines set for the entire network and respective importance levels G (j) are input as an initial configuration (step S1). Next, the initial relief degree PO (0) is calculated as the total sum of the importance levels (step S2). Next, on the premise of the inputted failure information, failure patterns are identified and made into a list format (step S3). All patterns for relieving the line corresponding to the failure pattern are found out to be a list (R) (step S4). Here, the relief rate Sm is set to 0 as an initial value (step S5). Next, the relief pattern (Rn) is sequentially extracted from the beginning of the list (step S6), the corresponding relief rate S (Rn) is calculated (step S7), and S (Rn) is compared with Sm (step S8). ). If it is larger than Sm, Sm is set to S (Rn) (step S9). Otherwise, step S9 is not executed and the next relief pattern is pooled (step S10). Thereby, a relief pattern having the maximum relief rate is searched.
[0036]
As described above, according to the present embodiment, by realizing the line remedy method that enhances the remedy effect by considering the importance of the line when relieving the failed line, and simultaneously adopting such a remedy method A network with improved reliability can be realized.
[0037]
Although the simplest network configuration example is shown here, the same method is applied even when the network configuration is larger or there are a plurality of lines between node devices and the initial number of lines is larger. be able to.
[0038]
【The invention's effect】
According to the present invention, in a complicated network configuration, it becomes possible to select the most effective line relief pattern that makes the most effective use of the remaining equipment in the event of a failure. Maximum reliability can be ensured.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining an embodiment of a line repair method according to the present invention;
FIG. 2 is a diagram for explaining an example of a relief pattern for showing the effect of the present invention;
FIG. 3 is a configuration diagram for explaining an example of a network to which the line repair method of the present invention is applied.
4 is a configuration diagram for explaining an optical cross-connect device in the network shown in FIG. 3;
FIG. 5 is a configuration diagram for explaining a monitoring control center in the network shown in FIG. 3;
FIG. 6 is a flowchart for explaining an algorithm of the line repair method of the present invention.
FIG. 7 is a diagram for explaining a conventional line repair method;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Node apparatus, 2 ... Transmission path, 3 ... Optical path, 4 ... Optical cross-connect apparatus, 5 ... Wavelength multiplexing apparatus, 11 ... UNI interface part, 12 ... NNI interface part, 13 ... Optical switch part, 14 ... Control part 15 ... communication line 16 ... monitoring control center 21 ... communication circuit 22 ... CPU 23 ... memory 24 ... man machine interface 25 ... input / output circuit 26 ... program memory 27 ... internal bus 28 ... light Line setting control program.

Claims (9)

In a network configured by connecting a plurality of node devices to each other via a transmission line, and selecting a route obtained by exchange connection by the plurality of node devices and setting a line ,
For each of a plurality of lines, determine the importance according to the magnitude of the effect when the line is disconnected, and assign a parameter that takes a larger value as the importance increases,
When a failure occurs in at least one of the node device and the transmission path,
For each of a plurality of line patterns that can be set using a route that does not include the location where the failure has occurred, obtain the sum of the parameters of each line included in the line pattern,
Comparing the sum of the parameters of each of the plurality of line patterns, selecting a line pattern in which the sum of the parameters is the largest value,
A line remedy method comprising setting a line included in the selected line pattern .   2. The line repair method according to claim 1, wherein the switching connection by the plurality of node devices is performed by an optical switch.   2. The line repair method according to claim 1, wherein the plurality of node devices are interconnected via a transmission line through wavelength multiplexing. For each parameter of the plurality of lines, if the line is at least one of defense, police, firefighting, and emergency services that save lives, give a higher value than the other lines as a highly important line The line repair method according to claim 1.   5. The line repair method according to claim 4, wherein the importance parameter is a traffic amount of the line.   5. The line repair method according to claim 4, wherein the importance parameter is a numerical value corresponding to a reciprocal of the repair order. A node device that performs exchange connection corresponding to the destination of the signal to be transmitted;
A transmission line connecting the node devices to each other;
Line setting means for setting a line by selecting a route obtained by exchange connection by the plurality of node devices;
A line disconnection detecting means for detecting a line disconnection due to a failure when a failure occurs in the route;
If spare route of Covering the disengaged state line is not, possess a line protection device for repairing a line disconnection state by changing the switched connection in the empty root to secure to remove the normal line,
The line rescue means is:
Information transfer means for transferring detected line disconnection information;
Information aggregating means for aggregating transferred line disconnection information;
An exchange connection change determination means for determining an exchange connection change to an empty route;
Information notifying means for notifying each node device of information of the determined exchange connection change;
Have
The exchange connection change determining means includes
For each line set in the network, a parameter that takes a larger value as the importance level is higher is assigned according to the importance level determined according to the magnitude of the effect when the line is disconnected. ,
When a failure occurs in a route, for each of a plurality of line patterns that can be set using a route excluding the route in which the failure has occurred , obtain the sum of the parameters of each line included in the line pattern ,
Comparing the sum of the parameters of each of the plurality of line patterns, selecting a line pattern in which the sum of the parameters is the largest value,
A network characterized by setting a line included in the selected line pattern . For each parameter of the plurality of lines, if the line is at least one of defense, police, firefighting, and emergency services that save lives, give a higher value than the other lines as a highly important line The network according to claim 7.   The plurality of node devices include an optical cross-connect device that performs switching connection using an optical switch, and a wavelength multiplexing device that multiplexes signals after switching connection by wavelength and separates wavelength-multiplexed signals from transmission lines individually. The network according to claim 7, wherein:

Images