JP3784199B2 - Transmission path redundancy method and system using the method - Google Patents

Transmission path redundancy method and system using the method Download PDF

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JP3784199B2
JP3784199B2 JP09558499A JP9558499A JP3784199B2 JP 3784199 B2 JP3784199 B2 JP 3784199B2 JP 09558499 A JP09558499 A JP 09558499A JP 9558499 A JP9558499 A JP 9558499A JP 3784199 B2 JP3784199 B2 JP 3784199B2
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transmission
predetermined signal
transmission path
transmission lines
switch
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JP2000295255A (en
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佳昭 中橋
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Toshiba Mitsubishi Electric Industrial Systems Corp
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Toshiba Mitsubishi Electric Industrial Systems Corp
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Description

【０００１】
【発明の属する技術分野】
本発明は、複数系統の伝送路を備えた例えばバス型ＬＡＮにおいて、何れかの系統の伝送路に障害が発生した場合に、正常な系統の伝送路に切り替えて用いる伝送路の冗長化方法及びその方法を用いたシステムに関する。
【０００２】
【従来の技術】
図１３は、従来のバス型ＬＡＮの構成を示すブロック図である。図１３において、１はバス型ＬＡＮの幹線伝送路であり、該幹線伝送路１の各ノードから分岐して複数の支線伝送路１０，１０，…が設けられている。また、支線伝送路１０，１０，…の１つにＬＡＮのホスト機能を有する監視制御局３が接続され、他の２つの支線伝送路１０，１０に端末装置としての入出力ターミナル４，４が夫々接続されている。
【０００３】
従来のバス型ＬＡＮは以上の如く構成されており、監視制御局３及び入出力ターミナル４，４の間のデータ伝送を幹線伝送路１及び支線伝送路１０，１０を介して行なう。
【０００４】
このようなバス型ＬＡＮの何れかの伝送路において障害が発生した場合、ＬＡＮ全体の機能が停止する。このため、例えば監視制御局３では、システムがダウンしたことによって障害が発生したことは確認できるが、障害箇所の特定、復旧等を行なうことは不可能である。特に、伝送路の切断等の物理的な障害が発生した場合には、作業員を派遣して目視にて伝送路の切断箇所を調査するか、又は支線伝送路１０，１０…、そして幹線伝送路１の順に伝送路を交換することにより障害箇所を特定した後で、伝送路の補修又は交換を行なっていた。
【０００５】
【発明が解決しようとする課題】
ところが、復旧作業の前提となる障害箇所の特定に多大な時間及び人手を要するため、この復旧までの間、ＬＡＮを使用できないという問題を抱えており、障害箇所の特定は、ＬＡＮの規模が大きくなるに従って困難になる。
【０００６】
なお、特開平６−６２０１７号公報においては、全ての伝送路を２系統とし、一方を常用系伝送路、他方を待機系伝送路とし、例えばＬＡＮ通信において発生したビットエラーを監視し、エラー回数が所定回数に達した場合に、常用系伝送路に障害が発生したと判断して、常用系伝送路から待機系伝送路に切り替える伝送路の冗長化方法が開示されており、これによれば、待機系伝送路に切り替えた後で常用系伝送路の復旧作業を行なうことができるという利点を有している。
【０００７】
本発明は斯かる事情に鑑みてなされたものであり、通常のデータ伝送におけるビットエラーを監視するのではなく、所定時間周期で各通信局が確認信号を送信し、これを受信する各通信局が所定時間以上、前記確認信号の受信が途絶えた場合に、現在使用中の系統の伝送路に障害が発生したと判断し、他の系統の伝送路に切り替えることにより、何れかの系統の伝送路に障害が発生した場合であっても、正常な系統の伝送路を使用している間に、障害箇所の特定、復旧作業を行なうことができる伝送路の冗長化方法及びその方法を用いたシステムを提供することを目的とする。
【０００８】
【課題を解決するための手段】
第１発明に係る伝送路の冗長化方法は、複数系統の伝送路の何れか１つに切替器を介して夫々接続された複数の通信局夫々が所定信号を時系列的に他の通信局へ送信すると共に他の通信局からの前記所定信号を受信し、前記複数の通信局の何れか１つが前記所定信号を所定時間受信できない場合に、前記所定信号を所定時間受信できなかった通信局が前記複数系統の伝送路の何れか１つに自身を接続している切替器へ切替指示を出力して他の系統の伝送路に接続するように切り替えることにより、他の通信局を前記複数系統の伝送路の何れか１つに接続している切替器夫々も前記他の系統の伝送路と接続するように切り替えられる伝送路の冗長化方法において、前記所定信号に伝送路の切替状態を示す情報を付加し、前記複数系統の伝送路に前記切替器を介して接続された表示手段に前記情報を表示することを特徴とする。
【０００９】
第２発明に係る伝送路の冗長化方法は、複数系統の伝送路の何れか１つに複数の通信局を夫々接続する複数の切替器夫々が所定信号を時系列的に他の切替器へ送信すると共に他の切替器からの前記所定信号を受信し、前記複数の切替器の何れか１つが前記所定信号を所定時間受信できない場合に、前記所定信号を所定時間受信できなかった切替器が自身に接続されている系統の伝送路を他の系統の伝送路に切り替えることにより、他の切替器夫々も前記他の系統の伝送路と接続するように切り替えられる伝送路の冗長化方法において、前記所定信号に伝送路の切替状態を示す情報を付加し、前記複数系統の伝送路に前記切替器を介して接続された表示手段に前記情報を表示することを特徴とする。
【００１１】
第３発明に係る伝送路の冗長化方法は、複数系統の伝送路に接続された第１通信局が前記複数系統の伝送路の何れか１つへ所定信号を時系列的に送信し、前記複数系統の伝送路の何れか１つに切替器を介して接続される複数の第２通信局が前記第１通信局からの前記所定信号を受信し、前記複数の第２通信局の何れか１つが前記所定信号を所定時間受信できない場合に、前記所定信号を所定時間受信できなかった第２通信局が前記複数系統の伝送路の何れか１つに自身を接続している切替器へ切替指示を出力して他の系統の伝送路に接続するように切り替えることにより、他の第２通信局を前記複数系統の伝送路の何れか１つに接続している切替器夫々も前記他の系統の伝送路と接続するように切り替えられる伝送路の冗長化方法において、前記所定信号に伝送路の切替状態を示す情報を付加し、前記複数系統の伝送路に前記切替器を介して接続された表示手段に前記情報を表示することを特徴とする。
【００１２】
第４発明に係る伝送路の冗長化方法は、複数系統の伝送路に接続された第１通信局が前記複数系統の伝送路の何れか１つへ所定信号を時系列的に送信し、前記複数系統の伝送路の何れか１つに複数の第２通信局を夫々接続する複数の切替器夫々が前記第１通信局からの前記所定信号を受信し、前記複数の切替器の何れか１つが前記所定信号を所定時間受信できない場合に、前記所定信号を所定時間受信できなかった切替器が自身に接続されている系統の伝送路を他の系統の伝送路に接続するように切り替えることにより、他の切替器夫々も前記他の系統の伝送路と接続するように切り替えられる伝送路の冗長化方法において、前記所定信号に伝送路の切替状態を示す情報を付加し、前記複数系統の伝送路に前記切替器を介して接続された表示手段に前記情報を表示することを特徴とする。
【００１４】
第５発明に係る伝送路の冗長化方法は、複数系統の伝送路に接続された複数の通信局夫々が前記複数系統の伝送路夫々を介して同一情報を他の通信局へ送信し、前記複数の通信局夫々が前記複数系統の伝送路夫々を介して同一情報を他の通信局から受信する伝送路の冗長化方法において、前記送信される情報には他の通信局での保存アドレスを指定する情報が付加されており、前記複数の通信局夫々は前記複数系統の伝送路夫々を介して他の通信局から受信した同一情報を同一のアドレスに格納することを特徴とする。
【００１５】
第６発明に係る伝送路の冗長化システムは、複数系統の伝送路と、該複数系統の伝送路の何れか１つに切替指示に応じて選択的に接続する複数の切替器と、夫々の切替器を介して前記複数系統の伝送路の何れか１つと接続されることにより通信を行なう複数の通信局とを含み、夫々の通信局は、所定信号を時系列的に他の通信局へ送信する送信手段と、他の通信局からの前記所定信号を受信する受信手段と、該受信手段による前記所定信号の受信が所定時間途絶えた場合に前記複数系統の伝送路の何れか１つに自身を接続している切替器へ前記切替指示を出力する出力手段とを備え、前記複数の通信局の何れか１つが前記複数系統の伝送路の何れか１つに自身を接続している切替器を前記切替指示によって他の系統の伝送路と接続するように切り替えた場合に、他の通信局を前記複数系統の伝送路の何れか１つに接続している切替器夫々も前記他の系統の伝送路と接続するように切り替えられるようになしてある伝送路の冗長化システムにおいて、前記所定信号に伝送路の切替状態を示す情報を付加する付加手段と、前記通信回線に接続され、前記情報を表示する表示手段とを備えることを特徴とする。
【００１６】
第７発明に係る伝送路の冗長化システムは、複数系統の伝送路と、該複数系統の伝送路の何れか１つに選択的に接続する複数の切替器と、夫々の切替器を介して前記複数系統の伝送路の何れか１つと接続されることにより通信を行なう複数の通信局とを含み、夫々の切替器は、所定信号を時系列的に他の切替器へ送信する送信手段と、他の切替器からの前記所定信号を受信する受信手段とを備え、自身が接続している系統の伝送路を前記受信手段による前記所定信号の受信が所定時間途絶えた場合に他の系統の伝送路に切り替えるように構成されており、前記複数の切替器の何れか１つが自身が接続している系統の伝送路を他の系統の伝送路に切り替えた場合に、他の切替器夫々も前記他の系統の伝送路と接続するように切り替えられるようになしてある伝送路の冗長化システムにおいて、前記所定信号に伝送路の切替状態を示す情報を付加する付加手段と、前記通信回線に接続され、前記情報を表示する表示手段とを備えることを特徴とする。
【００１８】
第８発明に係る伝送路の冗長化システムは、複数系統の伝送路と、該複数系統の伝送路に接続されていて何れか１つの系統の伝送路へ所定信号を時系列的に送信する第１通信局と、前記複数系統の伝送路の何れか１つに切替指示に応じて選択的に接続する複数の切替器と、夫々の切替器を介して前記複数系統の伝送路の何れか１つと接続されることにより通信を行なう複数の第２通信局とを含み、夫々の第２通信局は、前記第１通信局からの前記所定信号を受信する受信手段と、該受信手段による前記所定信号の受信が所定時間途絶えた場合に前記複数系統の伝送路の何れか１つに自身を接続している切替器へ前記切替指示を出力する出力手段とを備え、前記複数の第２通信局の何れか１つが前記複数系統の伝送路の何れか１つに自身を接続している切替器を前記切替指示によって他の系統の伝送路と接続するように切替えた場合に、他の第２通信局を前記複数系統の伝送路の何れか１つに接続している切替器夫々も前記他の系統の伝送路と接続するように切り替えられるようになしてある伝送路の冗長化システムにおいて、前記所定信号に伝送路の切替状態を示す情報を付加する付加手段と、前記通信回線に接続され、前記情報を表示する表示手段とを備えることを特徴とする。
【００１９】
第９発明に係る伝送路の冗長化システムは、複数系統の伝送路と、該複数系統の伝送路に接続されていて何れか１つの系統の伝送路へ所定信号を時系列的に送信する第１通信局と、前記複数の系統の伝送路の何れか１つに選択的に接続する複数の切替器と、夫々の切替器を介して前記複数系統の伝送路の何れか１つと接続されることにより通信を行なう複数の第２通信局とを含み、夫々の切替器は、前記第１通信局からの前記所定信号を受信する受信手段を備え、前記受信手段による前記所定信号の受信が所定時間途絶えた場合に自身を接続している系統の伝送路を他の系統の伝送路に切り替えるように構成されており、前記複数の切替器の何れか１つが自身が接続している系統の伝送路を他の系統の伝送路に切り替えた場合に、他の切替器夫々も前記他の系統の伝送路と接続するように切り替えられるようになしてある伝送路の冗長化システムにおいて、前記所定信号に伝送路の切替状態を示す情報を付加する付加手段と、前記通信回線に接続され、前記情報を表示する表示手段とを備えることを特徴とする。
【００２１】
第１０発明に係る伝送路の冗長化システムは、複数系統の伝送路と、該複数系統の伝送路に接続された複数の通信局とを含み、前記複数の通信局夫々が前記複数系統の伝送路夫々を介して同一情報を他の通信局へ送信し、前記複数の通信局夫々が前記複数系統の伝送路夫々を介して同一の他の通信局から同一情報を受信すべくなしてある伝送路の冗長化システムにおいて、前記複数の通信局夫々が前記複数系統の伝送路夫々を介して送信する情報には他の通信局での保存アドレスを指定する情報が付加されており、前記複数の通信局夫々は前記複数系統の伝送路夫々を介して他の通信局から受信した同一情報を同一のアドレスに格納すべくなしてあることを特徴とする。
【００２２】
【発明の実施の形態】
以下本発明をその実施の形態を示す図面に基づいて詳述する。
【００２３】
実施の形態１．
図１は、本発明に係る伝送路の冗長化方法を用いたシステムとしてのバス型ＬＡＮの実施の形態１を示すブロック図である。図１において、１，２は２系統とされたバス型ＬＡＮの幹線伝送路であり、各幹線伝送路１，２には、各ノードから分岐して複数の支線伝送路１０，２０が夫々設けられている。支線伝送路１０，１０，…の１つと、支線伝送路２０，２０，…の１つとは伝送路切替器５を介して監視制御局３へ接続されている。同様に異なる系統の支線伝送路１０，２０の対が伝送路切替器５を介して入出力ターミナル４，４に夫々接続されている。なお、図１においては図示を簡略化するために２つの入出力ターミナル４，４のみを示してある。
【００２４】
監視制御局３は、ＬＡＮのホストとして機能し、各入出力ターミナル４は、ＬＡＮを利用する端末装置等から構成されている。また、２系統とされた幹線伝送路１，２及び支線伝送路１０，２０は、これらの一方を通常用いるための常用系伝送路、他方を常用系伝送路に障害が発生した際に用いる待機系伝送路と夫々してあり、これらの伝送路の系統は各伝送路切替器５により切り替えられるようになっている。
【００２５】
つまり、図１に通常の状態を示す如く、各伝送路切替器５は、各通信局としての監視制御局３又は各入出力ターミナル４を常用系伝送路側に接続しており、この状態においては、常用系伝送路を用いた各通信局の間での通信が可能となっている。そして、例えば常用系伝送路に障害が発生した場合に、監視制御局３及び入出力ターミナル４，４は夫々の伝送路切替器５に対して伝送路切替信号を出力し、各伝送路切替器５がこの伝送路切替信号に応じて伝送路を切り替えるようになっている。
【００２６】
このような障害の検出は、監視制御局３及び入出力ターミナル４，４が個々に実行するが、この検出の原理を次に説明する。
【００２７】
監視制御局３及び入出力ターミナル４，４は、現在使用している伝送路に対して伝送路確認信号を所定時間周期で夫々出力する。この伝送路確認信号は、通常のＬＡＮ通信に用いられるＭＡＣフレームの送信タイミングとは無関係に出力されるが、通常のＭＡＣフレームに同期させてもよい。
【００２８】
図２は、通常のＭＡＣフレームの構成を示す模式図であり、図３は、伝送路確認信号の構成を示す模式図である。図２に示す如く、通常のＭＡＣフレームは、プリアンブルＰＡ、フレーム開始デリミタＳＦＤ、宛先アドレスＤＡ、発信元アドレスＳＡ、データ長ＤＬ、データ本体ＤＢ、及びフレーム検査シーケンスＦＣＳから構成されている。なお、括弧内は各部のオクテット数を示している。
【００２９】
プリアンブルＰＡは、ＭＡＣフレームの先頭に付与される同期記号であり、ＭＡＣフレームの送信時に他のデータとの衝突が検出されても、このプリアンブルＰＡの長さに応じた時間、再送を試みる。フレーム開始デリミタＳＦＤは、データフレームの開始位置を規定する。宛先アドレスＤＡは、宛先となる通信局のＭＡＣアドレスである。発信元アドレスＳＡは、発信元となる通信局のＭＡＣアドレスである。データ長ＤＬは、次に続くデータ本体ＤＢの長さをオクテット数で示す。データ本体ＤＢは、送信対象となるデータそのものである。また、フレーム検査シーケンスＦＣＳは、ＣＲＣ符号を含んだフレームチェック用のシーケンスである。
【００３０】
図３に示す如く、伝送路確認信号は、ＭＡＣフレームの形態を使用し、図２に示した通常のＭＡＣフレームのデータ本体ＤＢを空白としてあり、この部分にＭＡＣフレーム全体のオクテット数を規定数とするための穴埋め（パッド）を挿入してある。これによってＬＡＮの物理層のプロトコルを変更することなく実施することができる。なお、パッドに代えて伝送路確認信号であることを示す情報を挿入するような構成とすることも可能である。
【００３１】
このような伝送路確認信号を、その宛先アドレスＤＡをブロードキャストとして送信し、受信局は、そのデータ本体ＤＢを参照することにより、伝送路確認信号を識別するようになっている。
【００３２】
図４は、伝送路確認信号に基づいて各通信局が伝送路の系統を切り替える際の処理内容を示すフローチャートである。なお、監視制御局３及び各入出力ターミナル４は夫々同一の処理を行なう。まず、他局から伝送路確認信号を最後に受信してから所定時間内に再び伝送路確認信号を受信したか否かをチェックする（ステップ１１）。これは、前述した如く、受信したフレームのデータ本体を参照し、それがパッドであれば伝送路確認信号であると認識する。
【００３３】
所定時間内に受信した場合には、タイマをリセットする等してステップ１１を繰り返す。一方、受信しなかった場合には、現在使用している系統の伝送路に障害が発生したものと判断し、伝送路切替信号を伝送路切替器５へ出力して、伝送路の系統を切り替え（ステップ１２）、再びステップ１１からの処理を繰り返す。
【００３４】
なお、この伝送路の切り替えは、常用系伝送路からの待機系伝送路への切り替え、又は待機系伝送路からの常用系伝送路への切り替えの１方向に限定するものではなく、例えば伝送路切替信号が出力される毎に、伝送路切替器５が常用系及び待機系伝送路に交互に切り替えるように構成することもできる。
【００３５】
また、受信した伝送路切替信号の発信元アドレスを参照して、前記所定時間内に受信しなかった発信元アドレスに基づいて、障害が発生した伝送経路を特定するようにしてもよく、さらに障害が物理的な種類でなければ、コンピュータプログラムを用いて、特定された伝送経路等の情報に基づいて障害診断、障害復旧等を行なわせるように構成してもよい。
【００３６】
以上のように、１箇所の通信局で伝送路の系統の切り替えが実行されると、この通信局からの伝送路確認信号が他の通信局に届かなくなり、結果として全ての通信局が次々に伝送路の系統の切り替えを実行し、やがて全ての通信局が再び同一系統の伝送路を利用することになる。
【００３７】
実施の形態２．
図５は、本発明に係る伝送路の冗長化方法を用いたシステムとしてのバス型ＬＡＮの実施の形態２を示すブロック図である。上述した実施の形態１においては、図４に示した処理動作を監視制御局３及び入出力ターミナル４，４の夫々にて実行する必要があるが、本実施の形態においては、各伝送路切替器５にその処理動作を行なわせることにより、監視制御局３及び入出力ターミナル４，４が備えるソフトウェアに手を加えることなく、実施の形態１と同一の処理を実施することができる。
【００３８】
具体的には、各伝送路切替器５にＣＰＵ５０を設けてあり、ＣＰＵ５０が図４に示した処理動作を行なうようにしてある。
【００３９】
本実施の形態のその他の構成及び動作は実施の形態１と同様であり、重複する部分には同一の参照符号を付してその他の説明は省略する。
【００４０】
実施の形態３．
図６は、本発明に係る伝送路の冗長化方法を用いたシステムとしてのバス型ＬＡＮの実施の形態３を示すブロック図である。本実施の形態は、実施の形態２において１つの局としての管理装置６を伝送路切替器５を介して接続してある。管理装置６は、コンピュータ等の端末装置からなり、モニタ７を備えている。
【００４１】
図７は、伝送路切替情報を含んだ伝送路確認信号の構成を示す模式図である。また、本実施の形態においては、図７に示す如く、常用系伝送路又は待機系伝送路の何れの系統が使用中であるかを示す伝送路切替情報を伝送路確認信号のデータ本体部分に付加してある。なお、伝送路切替情報は、上述した常用系伝送路又は待機系伝送路の何れの系統を使用中かを示す以外の情報を含む構成としてもよく、その内容について限定するものではない。
【００４２】
管理装置６は、伝送路切替情報に基づいた内容をモニタ７上に表示するようになっており、例えば管理装置６がその伝送路切替器５を切り替えた後に、何れの伝送路の系統が使用中であるかを表示するようにしてある。
【００４３】
本実施の形態のその他の構成及び動作は実施の形態２と同様であり、重複する部分には同一の参照符号を付してその他の説明は省略する。
【００４４】
実施の形態４．
図８は、本発明に係る伝送路の冗長化方法を用いたシステムとしてのバス型ＬＡＮの実施の形態４を示すブロック図である。本実施の形態は、実施の形態１に対して、監視制御局３が伝送路切替器５を備えず、実施の形態３の如きモニタ７を備えている構成としてある。
【００４５】
なお、本実施の形態においては、監視制御局３のみが実施の形態３の如き伝送路切替情報を含んだ伝送路確認信号を送信するようになっており、この伝送路確認信号に基づいて各入出力ターミナル４は実施の形態１と同様に伝送路切替信号を出力する。一方、監視制御局３は、各入出力ターミナル４から受信する通常のＭＡＣフレームに基づいて同様の動作を行なうが、次にこの動作を説明する。
【００４６】
図９は、監視制御局３が伝送路を切り替える際の処理内容を示すフローチャートである。まず、入出力ターミナル４から受信した通常のＭＡＣフレームの発信元アドレスを参照してその発信元の入出力ターミナル４を特定する（ステップ２１）。なお、前記ＭＡＣフレームのデータ本体に発信元を特定できる情報を含ませ、この情報に基づいて発信元を特定する構成としてもよい。
【００４７】
次に、前記ＭＡＣフレームが常用系伝送路又は待機系伝送路の何れの系統を経由して送られてきたものかを特定する（ステップ２２）。この判断は、監視制御局３に接続された常用系伝送路又は待機系伝送路の何れの系統からＭＡＣフレームを受信したかを識別することによって判断することが可能であり、また、各入出力ターミナル４から送られるＭＡＣフレームのデータ本体に伝送路切替器５の切替情報を含ませて、この切替情報から判断することも可能である。
【００４８】
そして、特定した系統の伝送路を介して伝送路確認信号を送信し（ステップ２３）、必要であれば、この伝送路確認信号を送信した伝送路の系統を示す情報を、伝送路切替情報としてモニタ７上に表示させる（ステップ２４）。
【００４９】
このように、本実施の形態では監視制御局３が伝送路切替器５を備える必要がなく、また伝送路確認信号を監視制御局３からのみ送信するので、前述した実施の形態１〜３に比べてシステム構成が簡単であり、また伝送路負荷を軽減することもできる。
【００５０】
本実施の形態のその他の構成及び動作は実施の形態１と同様であり、重複する部分には同一の参照符号を付してその他の説明は省略する。
【００５１】
実施の形態５．
図１０は、本発明に係る伝送路の冗長化方法を用いたシステムとしてのバス型ＬＡＮの実施の形態５を示すブロック図である。本実施の形態は、実施の形態１に対して、各通信局が備えていた伝送路切替器５を排除した構成としてある。
【００５２】
図１１は、各通信局のデータ送信処理を示すフローチャートであり、図１２は、各通信局のデータ受信処理を示すフローチャートである。まず、図１１に示す如くデータ送信の際には、送信対象となるデータを含んだ通常のＭＡＣフレームを生成し（ステップ３１）、生成したＭＡＣフレームに宛先での保存アドレスを指定する情報を付加し、このようなＭＡＣフレームを２つ生成する（ステップ３２）。そして、一方のデータを常用系伝送路へ送信し（ステップ３３）、他方のデータを待機系伝送路へ送信する（ステップ３４）。
【００５３】
次に、このようなデータを受信する際には、図１２に示す如く、両方の系統の伝送路から同一データを受信する（ステップ４１）。この際に、何れの系統の伝送路から受信したかを識別することなく、これらのデータに含まれた保存アドレスに保存する（ステップ４２）。従って、一方の系統の伝送路に障害が発生した場合であっても、正常な側の系統の伝送路から同一内容のデータを受信することができるようになっている。
【００５４】
また、本実施の形態においては、実施の形態１〜４に示した如き伝送路確認信号が不要であり、送られたデータを受信側で指定通り保存することによって、伝送路切替時間が不要なシステム構成となる。
【００５５】
本実施の形態のその他の構成及び動作は実施の形態１と同様であり、重複する部分には同一の参照符号を付してその他の説明は省略する。
【００５６】
【発明の効果】
以上詳述した如く本発明に係る伝送路の冗長化方法及びその方法を用いたシステムにおいては、複数系統の伝送路の何れか１つに切替器を介して夫々接続された複数の通信局夫々が所定信号を時系列的に他の通信局へ送信すると共に他の通信局からの前記所定信号を受信し、前記複数の通信局の何れか１つが前記所定信号を所定時間受信できない場合に、前記所定信号を所定時間受信できなかった通信局が前記複数系統の伝送路の何れか１つに自身を接続している切替器へ切替指示を出力して他の系統の伝送路に接続するように切り替えることにより、他の通信局を前記複数系統の伝送路の何れか１つに接続している切替器夫々も前記他の系統の伝送路と接続するように切り替えられる構成とした。従って、複数系統の伝送路の内の何れかの系統の伝送路に障害が発生しても、複数の通信局の何れか１つが障害の発生を検出すれば伝送路の系統が切り替えられるので、この通信局からの伝送路確認信号が他の通信局に届かなくなり、結果として全ての通信局が次々に伝送路の系統の切り替えを実行し、やがて全ての通信局が再び同一系統の伝送路を利用することになる。従って、システム全体がダウンすることがなく、切り替えた後で、システムを使用しながら、障害が発生した系統の伝送路の復旧を図ることができる。更に、前記所定信号に伝送路の切替状態を示す情報を付加し、前記複数系統の伝送路に前記切替器を介して接続された表示手段に前記情報を表示する構成としたので、伝送路の切替状態をオペレータが視覚的に知ることができる。
【００５７】
また、本発明に係る伝送路の冗長化方法及びその方法を用いたシステムにおいては、複数系統の伝送路の何れか１つに複数の通信局を夫々接続する複数の切替器夫々が所定信号を時系列的に他の切替器へ送信すると共に他の切替器からの前記所定信号を受信し、前記複数の切替器の何れか１つが前記所定信号を所定時間受信できない場合に、前記所定信号を所定時間受信できなかった切替器が自身に接続されている系統の伝送路を他の系統の伝送路に切り替えることにより、他の切替器夫々も前記他の系統の伝送路と接続するように切り替えられる構成とした。従って、複数系統の伝送路を備える通信回線に本発明の切替器を取り付けるだけで、上述した発明の通信局が行なっていた機能を切替器に行なわせることができ、既存の通信局のソフトウェアに変更を加える必要がない。更に、前記所定信号に伝送路の切替状態を示す情報を付加し、前記複数系統の伝送路に前記切替器を介して接続された表示手段に前記情報を表示する構成としたので、伝送路の切替状態をオペレータが視覚的に知ることができる。
【００５９】
また、本発明に係る伝送路の冗長化方法及びその方法を用いたシステムにおいては、複数系統の伝送路に接続された第１通信局が前記複数系統の伝送路の何れか１つへ所定信号を時系列的に送信し、前記複数系統の伝送路の何れか１つに切替器を介して接続される複数の第２通信局が前記第１通信局からの前記所定信号を受信し、前記複数の第２通信局の何れか１つが前記所定信号を所定時間受信できない場合に、前記所定信号を所定時間受信できなかった第２通信局が前記複数系統の伝送路の何れか１つに自身を接続している切替器へ切替指示を出力して他の系統の伝送路に接続するように切り替えることにより、他の第２通信局を前記複数系統の伝送路の何れか１つに接続している切替器夫々も前記他の系統の伝送路と接続するように切り替えられる構成とした。従って、第１通信局が切替器を備える必要がなく、より簡易な構成とすることができる。更に、前記所定信号に伝送路の切替状態を示す情報を付加し、前記複数系統の伝送路に前記切替器を介して接続された表示手段に前記情報を表示する構成としたので、伝送路の切替状態をオペレータが視覚的に知ることができる。
【００６０】
また、本発明に係る伝送路の冗長化方法及びその方法を用いたシステムにおいては、複数系統の伝送路に接続された第１通信局が前記複数系統の伝送路の何れか１つへ所定信号を時系列的に送信し、前記複数系統の伝送路の何れか１つに複数の第２通信局を夫々接続する複数の切替器夫々が前記第１通信局からの前記所定信号を受信し、前記複数の切替器の何れか１つが前記所定信号を所定時間受信できない場合に、前記所定信号を所定時間受信できなかった切替器が自身に接続されている系統の伝送路を他の系統の伝送路に接続するように切り替えることにより、他の切替器夫々も前記他の系統の伝送路と接続するように切り替えられる構成とした。従って、例えば、複数系統の伝送路を備える通信回線に本発明の切替器を取り付けるだけで、上述した発明の通信局が行なっていた機能を切替器に行なわせることができ、既存の通信局のソフトウェアに変更を加える必要がない。更に、前記所定信号に伝送路の切替状態を示す情報を付加し、前記複数系統の伝送路に前記切替器を介して接続された表示手段に前記情報を表示する構成としたので、伝送路の切替状態をオペレータが視覚的に知ることができる。
【００６２】
さらに、本発明に係る伝送路の冗長化方法及びその方法を用いたシステムにおいては、複数系統の伝送路に接続された複数の通信局夫々が前記複数系統の伝送路夫々を介して同一情報を他の通信局へ送信し、前記複数の通信局夫々が前記複数系統の伝送路夫々を介して同一情報を他の通信局から受信し、同一のアドレスに格納する構成としたので、いずれか一方の系統の伝送路に障害が発生していてその伝送路から情報を受信できない場合にも他方の伝送路から情報を受信することができるので、上述した何れの発明における切替器を備える必要がなく構成が簡易であり、切り替え自体をも不要とすることができる等、本発明は優れた効果を奏する。
【図面の簡単な説明】
【図１】 本発明に係る伝送路の冗長化方法を用いたシステムとしてのバス型ＬＡＮの実施の形態１を示すブロック図である。
【図２】 通常のＭＡＣフレームの構成を示す模式図である。
【図３】 伝送路確認信号の構成を示す模式図である。
【図４】 伝送路確認信号に基づいて各通信局が伝送路の系統を切り替える際の処理内容を示すフローチャートである。
【図５】 本発明に係る伝送路の冗長化方法を用いたシステムとしてのバス型ＬＡＮの実施の形態２を示すブロック図である。
【図６】 本発明に係る伝送路の冗長化方法を用いたシステムとしてのバス型ＬＡＮの実施の形態３を示すブロック図である。
【図７】 伝送路切替情報を含んだ伝送路確認信号の構成を示す模式図である。
【図８】 本発明に係る伝送路の冗長化方法を用いたシステムとしてのバス型ＬＡＮの実施の形態４を示すブロック図である。
【図９】 監視制御局が伝送路を切り替える際の処理内容を示すフローチャートである。
【図１０】 本発明に係る伝送路の冗長化方法を用いたシステムとしてのバス型ＬＡＮの実施の形態５を示すブロック図である。
【図１１】 各通信局のデータ送信処理を示すフローチャートである。
【図１２】 各通信局のデータ受信処理を示すフローチャートである。
【図１３】 従来のバス型ＬＡＮの構成を示すブロック図である。
【符号の説明】
１ 幹線伝送路（常用系）、２ 幹線伝送路（待機系）、３ 監視制御局、
４ 入出力ターミナル、５ 伝送路切替器、６ 管理装置、７ モニタ、
１０ 支線伝送路（常用系）、２０ 支線伝送路（待機系）、５０ ＣＰＵ。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a redundancy method for a transmission line that is used by switching to a normal transmission line when a failure occurs in any transmission line in, for example, a bus LAN having a plurality of transmission lines, and The present invention relates to a system using the method.
[0002]
[Prior art]
FIG. 13 is a block diagram showing a configuration of a conventional bus LAN. In FIG. 13, reference numeral 1 denotes a bus-type LAN trunk transmission line, which is branched from each node of the trunk transmission line 1 and provided with a plurality of branch transmission lines 10, 10,. In addition, a supervisory control station 3 having a LAN host function is connected to one of the branch transmission lines 10, 10,..., And input / output terminals 4, 4 as terminal devices are connected to the other two branch transmission lines 10, 10. Each is connected.
[0003]
The conventional bus type LAN is configured as described above, and performs data transmission between the supervisory control station 3 and the input / output terminals 4 and 4 through the main transmission line 1 and the branch transmission lines 10 and 10.
[0004]
When a failure occurs in any transmission path of such a bus type LAN, the function of the entire LAN is stopped. For this reason, for example, the supervisory control station 3 can confirm that a failure has occurred due to the system being down, but it is impossible to identify or restore the failure location. In particular, when a physical failure such as a disconnection of the transmission line occurs, an operator is dispatched to visually check the cut part of the transmission line, or the branch transmission lines 10, 10,. After identifying the fault location by exchanging the transmission path in the order of the path 1, the transmission path is repaired or replaced.
[0005]
[Problems to be solved by the invention]
However, since it takes a lot of time and manpower to identify the fault location that is the premise of the recovery work, there is a problem that the LAN cannot be used until this recovery. The fault location is identified by the large scale of the LAN. It becomes difficult as it becomes.
[0006]
In Japanese Patent Laid-Open No. 6-62017, all transmission paths are two systems, one is a regular transmission path, and the other is a standby transmission path. For example, bit errors occurring in LAN communication are monitored, and the number of errors When a predetermined number of times is reached, it is determined that a failure has occurred in the normal transmission line, and a transmission path redundancy method for switching from the normal transmission line to the standby transmission line is disclosed. In addition, after switching to the standby transmission line, there is an advantage that the work for restoring the normal transmission line can be performed.
[0007]
The present invention has been made in view of such circumstances, and does not monitor bit errors in normal data transmission, but each communication station transmits a confirmation signal at a predetermined time period and receives this signal. When the reception of the confirmation signal is interrupted for a predetermined time or longer, it is determined that a failure has occurred in the transmission path of the currently used system, and transmission to any system is performed by switching to the transmission path of another system. Even when a fault occurs in the path, the transmission path redundancy method and its method can be used so that the fault location can be identified and restored while using a normal transmission path. The purpose is to provide a system.
[0008]
[Means for Solving the Problems]
  According to a first aspect of the present invention, there is provided a redundancy method for a transmission line in which a plurality of communication stations respectively connected to any one of a plurality of transmission lines via a switch receive a predetermined signal in time series. A communication station that has received the predetermined signal from another communication station and has not received the predetermined signal for a predetermined time when any one of the plurality of communication stations cannot receive the predetermined signal for a predetermined time Outputs a switching instruction to a switch that is connected to any one of the transmission lines of the plurality of systems so as to connect to a transmission line of another system, thereby switching another communication station to the plurality of transmission lines. Each switch connected to one of the transmission lines of the system is also switched to connect to the transmission line of the other system.In the transmission path redundancy method, information indicating a switching state of a transmission path is added to the predetermined signal, and the information is displayed on display means connected to the transmission lines of the plurality of systems via the switch.It is characterized by that.
[0009]
  According to a second aspect of the present invention, there is provided a redundancy method for a transmission line, wherein each of a plurality of switches each connecting a plurality of communication stations to any one of a plurality of transmission lines sends a predetermined signal to another switch in time series. A switch that has received the predetermined signal from another switch and has not received the predetermined signal for a predetermined time when any one of the plurality of switches cannot receive the predetermined signal for a predetermined time; By switching the transmission path of the system connected to itself to the transmission path of the other system, each of the other switchers can be switched to connect to the transmission path of the other system.In the transmission path redundancy method, information indicating a switching state of a transmission path is added to the predetermined signal, and the information is displayed on display means connected to the transmission lines of the plurality of systems via the switch.It is characterized by that.
[0011]
  Third inventionIn the redundancy method for transmission lines according to the first communication station connected to a plurality of transmission lines, a first communication station transmits a predetermined signal to any one of the plurality of transmission lines in time series, and A plurality of second communication stations connected to any one of the transmission paths via a switch receives the predetermined signal from the first communication station, and any one of the plurality of second communication stations is the When a predetermined signal cannot be received for a predetermined time, the second communication station that has not received the predetermined signal for a predetermined time outputs a switching instruction to a switch connected to any one of the transmission lines of the plurality of systems. Then, by switching so as to connect to another system transmission path, each of the switches that connect the other second communication station to any one of the plurality of system transmission paths also transmits to the other system. Can be switched to connect to the roadIn the transmission path redundancy method, information indicating a switching state of a transmission path is added to the predetermined signal, and the information is displayed on display means connected to the transmission lines of the plurality of systems via the switch.It is characterized by that.
[0012]
  Fourth inventionIn the redundancy method for transmission lines according to the first communication station connected to a plurality of transmission lines, a first communication station transmits a predetermined signal to any one of the plurality of transmission lines in time series, and A plurality of switches each connecting a plurality of second communication stations to any one of the transmission paths each receive the predetermined signal from the first communication station, and any one of the plurality of switches is the predetermined When a signal cannot be received for a predetermined time, the switch that has not received the predetermined signal for a predetermined time can be switched to connect the transmission line of the system connected to itself to the transmission path of another system, Each switch is also switched to connect to the transmission line of the other system.In the transmission path redundancy method, information indicating a switching state of a transmission path is added to the predetermined signal, and the information is displayed on display means connected to the transmission lines of the plurality of systems via the switch.It is characterized by that.
[0014]
  5th inventionIn the transmission path redundancy method according to the first aspect, each of a plurality of communication stations connected to a plurality of transmission paths transmits the same information to another communication station via each of the plurality of transmission paths. Each station receives the same information from another communication station via each of the plurality of transmission lines.In the transmission path redundancy method, information for specifying a storage address in another communication station is added to the transmitted information, and each of the plurality of communication stations passes through each of the plurality of transmission paths. Store the same information received from other communication stations at the same addressIt is characterized by that.
[0015]
  6th inventionThe transmission line redundancy system according to the present invention includes a plurality of transmission lines, a plurality of switching units that selectively connect to any one of the plurality of transmission lines according to a switching instruction, and each switching unit. A plurality of communication stations that communicate with each other by being connected to any one of the transmission lines of the plurality of systems, and each communication station transmits a predetermined signal to other communication stations in time series. Means, receiving means for receiving the predetermined signal from another communication station, and connecting itself to any one of the transmission lines of the plurality of systems when reception of the predetermined signal by the receiving means is interrupted for a predetermined time Output means for outputting the switching instruction to a switching device, and a switching device in which any one of the plurality of communication stations is connected to any one of the transmission lines of the plurality of systems. Switch to connect to another system's transmission line by switching instruction If there are no other communication station to be switched to the plurality of systems switch husband connected either to a single transmission path s also connected to the transmission path of the other strainsThe transmission line redundancy system includes an adding unit that adds information indicating a switching state of the transmission line to the predetermined signal, and a display unit that is connected to the communication line and displays the information.It is characterized by.
[0016]
  7th inventionThe transmission line redundancy system according to the present invention includes a plurality of transmission lines, a plurality of switches selectively connected to any one of the plurality of transmission lines, and the plurality of systems via each switch. A plurality of communication stations that communicate with each other by being connected to any one of the transmission paths, and each switching unit includes a transmission unit that transmits a predetermined signal to another switching unit in time series, Receiving means for receiving the predetermined signal from the switch, and when the reception of the predetermined signal by the receiving means is interrupted for a predetermined time, the transmission path of the system to which it is connected is changed to a transmission path of another system When one of the plurality of switches is switched to a transmission path of a system to which one of the plurality of switches is connected to a transmission path of another system, each of the other switches is also the other Can be switched to connect to the transmission line of the grid ThatThe transmission line redundancy system includes an adding unit that adds information indicating a switching state of the transmission line to the predetermined signal, and a display unit that is connected to the communication line and displays the information.It is characterized by.
[0018]
  Eighth inventionThe transmission line redundancy system according to the present invention includes a plurality of transmission lines and a first communication station connected to the plurality of transmission lines and transmitting a predetermined signal to any one of the transmission lines in time series. And a plurality of switching units selectively connected to any one of the plurality of transmission lines according to a switching instruction, and connected to any one of the plurality of transmission lines via each switching unit. A plurality of second communication stations that communicate with each other, each of the second communication stations receiving the predetermined signal from the first communication station, and receiving the predetermined signal by the receiving unit Output means for outputting the switching instruction to a switch that is connected to any one of the transmission lines of the plurality of systems when the communication is interrupted for a predetermined time, and any one of the plurality of second communication stations One is connecting itself to any one of the multiple transmission lines When the switching device is switched so as to be connected to a transmission line of another system according to the switching instruction, each of the switching devices that connects another second communication station to any one of the transmission lines of the plurality of systems. It can be switched to connect to the transmission line of the other system.The transmission line redundancy system includes an adding unit that adds information indicating a switching state of the transmission line to the predetermined signal, and a display unit that is connected to the communication line and displays the information.It is characterized by.
[0019]
  Ninth inventionThe transmission line redundancy system according to the present invention includes a plurality of transmission lines and a first communication station connected to the plurality of transmission lines and transmitting a predetermined signal to any one of the transmission lines in time series. A plurality of switches selectively connected to any one of the plurality of transmission lines, and communication by being connected to any one of the plurality of transmission lines via each switch A plurality of second communication stations, each switch comprising receiving means for receiving the predetermined signal from the first communication station, and reception of the predetermined signal by the receiving means has been interrupted for a predetermined time In this case, it is configured to switch the transmission path of the system to which the system is connected to the transmission path of another system, and any one of the plurality of switching devices is configured to switch the transmission path of the system to which the system is connected. When switching to the transmission path of the other system, the other switch There are no to be switched to connect a transmission line of other strainsThe transmission line redundancy system includes an adding unit that adds information indicating a switching state of the transmission line to the predetermined signal, and a display unit that is connected to the communication line and displays the information.It is characterized by.
[0021]
  10th inventionThe transmission line redundancy system according to the present invention includes a plurality of transmission paths and a plurality of communication stations connected to the plurality of transmission paths, and each of the plurality of communication stations has a plurality of transmission paths. The same information is transmitted to other communication stations, and each of the plurality of communication stations is supposed to receive the same information from the same other communication station via each of the plurality of transmission paths.In the redundant system of transmission lines, information that designates a storage address in another communication station is added to information that each of the plurality of communication stations transmits via each of the plurality of transmission lines. Each of the communication stations is designed to store the same information received from other communication stations via the plurality of transmission lines in the same address.It is characterized by that.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
[0023]
Embodiment 1 FIG.
FIG. 1 is a block diagram showing a first embodiment of a bus type LAN as a system using a transmission path redundancy method according to the present invention. In FIG. 1, reference numerals 1 and 2 denote two-system bus LAN trunk transmission lines, and each of the trunk transmission lines 1 and 2 is provided with a plurality of branch transmission lines 10 and 20 branched from each node. It has been. .. And one of the branch line transmission paths 20, 20,... Are connected to the monitoring control station 3 via the transmission line switch 5. Similarly, pairs of branch line transmission lines 10 and 20 of different systems are connected to the input / output terminals 4 and 4 via the transmission line switching unit 5, respectively. In FIG. 1, only two input / output terminals 4 and 4 are shown to simplify the illustration.
[0024]
The supervisory control station 3 functions as a LAN host, and each input / output terminal 4 includes a terminal device using the LAN. In addition, the main transmission lines 1 and 2 and the branch transmission lines 10 and 20 that are made into two systems are the standby transmission line when one of these is normally used, and the other is used when the failure occurs in the normal transmission line. Each transmission line system is switched by each transmission line switch 5.
[0025]
That is, as shown in the normal state in FIG. 1, each transmission line switching unit 5 connects the monitoring control station 3 or each input / output terminal 4 as each communication station to the regular transmission line side. Communication between each communication station using the regular transmission line is possible. For example, when a failure occurs in the regular transmission line, the supervisory control station 3 and the input / output terminals 4 and 4 output transmission line switching signals to the respective transmission line switching units 5, and each transmission line switching unit 5 switches the transmission line in response to the transmission line switching signal.
[0026]
The detection of such a failure is performed individually by the monitoring control station 3 and the input / output terminals 4 and 4. The principle of this detection will be described next.
[0027]
The supervisory control station 3 and the input / output terminals 4 and 4 each output a transmission path confirmation signal to the currently used transmission path at a predetermined time period. The transmission path confirmation signal is output regardless of the transmission timing of the MAC frame used for normal LAN communication, but may be synchronized with the normal MAC frame.
[0028]
FIG. 2 is a schematic diagram illustrating a configuration of a normal MAC frame, and FIG. 3 is a schematic diagram illustrating a configuration of a transmission path confirmation signal. As shown in FIG. 2, a normal MAC frame includes a preamble PA, a frame start delimiter SFD, a destination address DA, a source address SA, a data length DL, a data body DB, and a frame inspection sequence FCS. Note that the number of octets in each part is shown in parentheses.
[0029]
The preamble PA is a synchronization symbol given to the head of the MAC frame. Even if a collision with other data is detected during transmission of the MAC frame, retransmission is attempted for a time corresponding to the length of the preamble PA. The frame start delimiter SFD defines the start position of the data frame. The destination address DA is the MAC address of the destination communication station. The source address SA is the MAC address of the communication station that is the source. The data length DL indicates the length of the following data body DB in the number of octets. The data body DB is data itself to be transmitted. The frame check sequence FCS is a frame check sequence including a CRC code.
[0030]
As shown in FIG. 3, the transmission path confirmation signal uses the form of a MAC frame, and the data body DB of the normal MAC frame shown in FIG. 2 is left blank. In this part, the number of octets of the entire MAC frame is a specified number. A hole filling (pad) is inserted. This can be implemented without changing the protocol of the physical layer of the LAN. It is also possible to adopt a configuration in which information indicating a transmission path confirmation signal is inserted instead of the pad.
[0031]
Such a transmission path confirmation signal is transmitted by broadcasting the destination address DA, and the receiving station identifies the transmission path confirmation signal by referring to the data body DB.
[0032]
FIG. 4 is a flowchart showing the processing contents when each communication station switches the transmission path system based on the transmission path confirmation signal. The supervisory control station 3 and each input / output terminal 4 perform the same processing. First, it is checked whether or not the transmission path confirmation signal has been received again within a predetermined time since the transmission path confirmation signal was last received from another station (step 11). As described above, this refers to the data body of the received frame, and if it is a pad, it is recognized as a transmission path confirmation signal.
[0033]
If it is received within the predetermined time, step 11 is repeated by resetting the timer or the like. On the other hand, if it is not received, it is determined that a failure has occurred in the transmission path of the currently used system, and a transmission path switching signal is output to the transmission path switch 5 to switch the transmission path system. (Step 12), the processing from Step 11 is repeated again.
[0034]
Note that the switching of the transmission path is not limited to one direction of switching from the normal transmission path to the standby transmission path or switching from the standby transmission path to the regular transmission path. Each time the switching signal is output, the transmission path switch 5 can be configured to alternately switch between the normal transmission system and the standby transmission path.
[0035]
Further, referring to the source address of the received transmission path switching signal, the transmission path in which the failure has occurred may be specified based on the source address that has not been received within the predetermined time. If it is not a physical type, a computer program may be used to perform fault diagnosis, fault recovery, etc. based on information such as the specified transmission path.
[0036]
As described above, when the transmission line system is switched at one communication station, the transmission line confirmation signal from this communication station does not reach the other communication stations, and as a result, all communication stations are connected one after another. The transmission line system is switched, and eventually all communication stations use the same system transmission line again.
[0037]
Embodiment 2. FIG.
FIG. 5 is a block diagram showing a second embodiment of a bus LAN as a system using the transmission path redundancy method according to the present invention. In the first embodiment described above, it is necessary to execute the processing operation shown in FIG. 4 in each of the monitoring control station 3 and the input / output terminals 4 and 4. In this embodiment, each transmission path switching is performed. By causing the device 5 to perform the processing operation, the same processing as in the first embodiment can be performed without modifying the software provided in the monitoring control station 3 and the input / output terminals 4 and 4.
[0038]
Specifically, each transmission path switch 5 is provided with a CPU 50, and the CPU 50 performs the processing operation shown in FIG.
[0039]
Other configurations and operations of the present embodiment are the same as those of the first embodiment, and overlapping portions are denoted by the same reference numerals, and other descriptions are omitted.
[0040]
Embodiment 3 FIG.
FIG. 6 is a block diagram showing a third embodiment of a bus LAN as a system using the transmission path redundancy method according to the present invention. In the present embodiment, the management device 6 as one station in the second embodiment is connected via the transmission line switch 5. The management device 6 includes a terminal device such as a computer and includes a monitor 7.
[0041]
FIG. 7 is a schematic diagram illustrating a configuration of a transmission path confirmation signal including transmission path switching information. Further, in the present embodiment, as shown in FIG. 7, transmission line switching information indicating which of the normal transmission line and the standby transmission line is in use is included in the data body portion of the transmission line confirmation signal. It has been added. The transmission path switching information may be configured to include information other than indicating which of the above-described regular transmission line or standby transmission line is in use, and the contents thereof are not limited.
[0042]
The management apparatus 6 displays the contents based on the transmission path switching information on the monitor 7. For example, after the management apparatus 6 switches the transmission path switch 5, which transmission path system is used. It is displayed whether it is inside.
[0043]
Other configurations and operations of the present embodiment are the same as those of the second embodiment, and duplicated portions are denoted by the same reference numerals, and other descriptions are omitted.
[0044]
Embodiment 4 FIG.
FIG. 8 is a block diagram showing Embodiment 4 of a bus type LAN as a system using the transmission path redundancy method according to the present invention. In the present embodiment, the monitoring control station 3 does not include the transmission path switch 5 but includes the monitor 7 as in the third embodiment, as compared with the first embodiment.
[0045]
In the present embodiment, only the supervisory control station 3 transmits a transmission path confirmation signal including transmission path switching information as in the third embodiment, and based on this transmission path confirmation signal, The input / output terminal 4 outputs a transmission path switching signal as in the first embodiment. On the other hand, the supervisory control station 3 performs the same operation based on the normal MAC frame received from each input / output terminal 4, and this operation will be described next.
[0046]
FIG. 9 is a flowchart showing the processing contents when the supervisory control station 3 switches the transmission path. First, referring to the source address of a normal MAC frame received from the input / output terminal 4, the source input / output terminal 4 is specified (step 21). In addition, it is good also as a structure which includes the information which can specify a transmission origin in the data main body of the said MAC frame, and specifies a transmission origin based on this information.
[0047]
Next, it is specified whether the MAC frame is sent via the normal transmission line or the standby transmission line (step 22). This determination can be made by identifying whether the MAC frame has been received from either the regular transmission line or the standby transmission line connected to the supervisory control station 3. It is also possible to include the switching information of the transmission path switch 5 in the data body of the MAC frame sent from the terminal 4 and make a judgment from this switching information.
[0048]
Then, a transmission path confirmation signal is transmitted through the identified transmission path (step 23). If necessary, information indicating the transmission path system that has transmitted the transmission path confirmation signal is used as transmission path switching information. It is displayed on the monitor 7 (step 24).
[0049]
As described above, in this embodiment, the monitoring control station 3 does not need to include the transmission path switch 5, and the transmission path confirmation signal is transmitted only from the monitoring control station 3. Compared with the system configuration, the transmission line load can be reduced.
[0050]
Other configurations and operations of the present embodiment are the same as those of the first embodiment, and overlapping portions are denoted by the same reference numerals, and other descriptions are omitted.
[0051]
Embodiment 5. FIG.
FIG. 10 is a block diagram showing a fifth embodiment of a bus type LAN as a system using the transmission path redundancy method according to the present invention. The present embodiment has a configuration in which the transmission path switch 5 provided in each communication station is excluded from the first embodiment.
[0052]
FIG. 11 is a flowchart showing data transmission processing of each communication station, and FIG. 12 is a flowchart showing data reception processing of each communication station. First, as shown in FIG. 11, when transmitting data, a normal MAC frame including data to be transmitted is generated (step 31), and information specifying a storage address at the destination is added to the generated MAC frame. Then, two such MAC frames are generated (step 32). Then, one data is transmitted to the regular transmission line (step 33), and the other data is transmitted to the standby transmission line (step 34).
[0053]
Next, when such data is received, the same data is received from the transmission paths of both systems as shown in FIG. 12 (step 41). At this time, it is stored in the storage address included in these data without identifying which transmission line of the system is received (step 42). Therefore, even when a failure occurs in one transmission line, data having the same content can be received from the transmission line in the normal system.
[0054]
Further, in this embodiment, the transmission line confirmation signal as shown in the first to fourth embodiments is not necessary, and transmission line switching time is unnecessary by storing the transmitted data as specified on the receiving side. System configuration.
[0055]
Other configurations and operations of the present embodiment are the same as those of the first embodiment, and overlapping portions are denoted by the same reference numerals, and other descriptions are omitted.
[0056]
【The invention's effect】
  As described above in detail, in the transmission line redundancy method and the system using the method according to the present invention, each of a plurality of communication stations respectively connected to any one of a plurality of transmission lines via a switch. Transmits a predetermined signal to another communication station in time series and receives the predetermined signal from another communication station, and when any one of the plurality of communication stations cannot receive the predetermined signal for a predetermined time, A communication station that has not received the predetermined signal for a predetermined time outputs a switching instruction to a switch that is connected to one of the transmission lines of the plurality of systems and connects to a transmission line of another system. By switching to, each switching unit that connects other communication stations to any one of the transmission lines of the plurality of systems can be switched to connect to the transmission lines of the other systems. Therefore, even if a failure occurs in any of the transmission lines of the plurality of transmission lines, the transmission line system is switched if any one of the plurality of communication stations detects the occurrence of the failure. The transmission path confirmation signal from this communication station does not reach the other communication stations, and as a result, all the communication stations execute the switching of the transmission path system one after another. Will be used. Therefore, the entire system does not go down, and after switching, the transmission path of the system in which the failure has occurred can be restored while using the system.Furthermore, since the information indicating the switching state of the transmission path is added to the predetermined signal, and the information is displayed on the display means connected to the transmission paths of the plurality of systems via the switch, The operator can visually know the switching state.
[0057]
  Also, in the transmission line redundancy method and the system using the method according to the present invention, each of a plurality of switching units respectively connecting a plurality of communication stations to any one of a plurality of transmission lines transmits a predetermined signal. When the predetermined signal is transmitted to another switch in time series and the predetermined signal from the other switch is received, and any one of the plurality of switches cannot receive the predetermined signal for a predetermined time, the predetermined signal is A switch that has not been able to receive for a predetermined time switches the transmission path of the system connected to itself to the transmission path of the other system, so that each of the other switch is also connected to the transmission path of the other system. It was set as the structure. Therefore, by simply attaching the switch of the present invention to a communication line having a plurality of transmission lines, the function performed by the communication station of the above-described invention can be performed by the switch. There is no need to make changes.Furthermore, since the information indicating the switching state of the transmission path is added to the predetermined signal, and the information is displayed on the display means connected to the transmission paths of the plurality of systems via the switch, The operator can visually know the switching state.
[0059]
  In the transmission line redundancy method and system using the method according to the present invention, a first communication station connected to a plurality of transmission lines transmits a predetermined signal to any one of the plurality of transmission lines. And a plurality of second communication stations connected to any one of the plurality of transmission lines via a switch receive the predetermined signal from the first communication station, If any one of a plurality of second communication stations cannot receive the predetermined signal for a predetermined time, the second communication station that has failed to receive the predetermined signal for a predetermined time is assigned to any one of the transmission lines of the plurality of systems. The other second communication station is connected to any one of the transmission lines of the plurality of systems by outputting a switching instruction to the switching device connected to and connecting to the transmission system of another system. Switch so that each switch is connected to the transmission line of the other system. It was configured to be replaced. Therefore, it is not necessary for the first communication station to include a switch, and a simpler configuration can be achieved.Furthermore, since the information indicating the switching state of the transmission path is added to the predetermined signal, and the information is displayed on the display means connected to the transmission paths of the plurality of systems via the switch, The operator can visually know the switching state.
[0060]
  In the transmission line redundancy method and system using the method according to the present invention, a first communication station connected to a plurality of transmission lines transmits a predetermined signal to any one of the plurality of transmission lines. A plurality of switch units each connecting a plurality of second communication stations to any one of the transmission lines of the plurality of systems receive the predetermined signal from the first communication station, If any one of the plurality of switches cannot receive the predetermined signal for a predetermined time, the switch that has failed to receive the predetermined signal for a predetermined time transmits the transmission line of the system connected to itself to another system. By switching so as to be connected to a path, each of the other switchers can be switched so as to be connected to a transmission path of the other system. Therefore, for example, by simply attaching the switch of the present invention to a communication line having a plurality of transmission paths, the switch can perform the function performed by the communication station of the above-described invention. There is no need to make changes to the software.Furthermore, since the information indicating the switching state of the transmission path is added to the predetermined signal, and the information is displayed on the display means connected to the transmission paths of the plurality of systems via the switch, The operator can visually know the switching state.
[0062]
  Further, in the transmission line redundancy method and system using the method according to the present invention, each of a plurality of communication stations connected to a plurality of transmission paths receives the same information via each of the plurality of transmission paths. Transmit to other communication stations, and each of the plurality of communication stations receives the same information from the other communication stations via the plurality of transmission lines.And store at the same addressBecause it was configured toSince it is possible to receive information from the other transmission path even if the transmission path of either system has failed and information cannot be received from that transmission path,It is not necessary to provide the switch in any of the above-described inventions, the configuration is simple, and the switching itself is unnecessary, and the present invention has excellent effects.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a first embodiment of a bus type LAN as a system using a transmission path redundancy method according to the present invention.
FIG. 2 is a schematic diagram showing a configuration of a normal MAC frame.
FIG. 3 is a schematic diagram showing a configuration of a transmission path confirmation signal.
FIG. 4 is a flowchart showing processing contents when each communication station switches a transmission line system based on a transmission line confirmation signal;
FIG. 5 is a block diagram showing a second embodiment of a bus type LAN as a system using the transmission path redundancy method according to the present invention.
FIG. 6 is a block diagram showing a third embodiment of a bus type LAN as a system using the transmission path redundancy method according to the present invention.
FIG. 7 is a schematic diagram showing a configuration of a transmission path confirmation signal including transmission path switching information.
FIG. 8 is a block diagram showing a fourth embodiment of a bus type LAN as a system using the transmission path redundancy method according to the present invention.
FIG. 9 is a flowchart showing the processing contents when the supervisory control station switches the transmission path.
FIG. 10 is a block diagram showing a fifth embodiment of a bus type LAN as a system using the transmission path redundancy method according to the present invention.
FIG. 11 is a flowchart showing data transmission processing of each communication station.
FIG. 12 is a flowchart showing data reception processing of each communication station.
FIG. 13 is a block diagram showing a configuration of a conventional bus type LAN.
[Explanation of symbols]
1 trunk transmission line (normal system) 2 trunk transmission line (standby system) 3 supervisory control station,
4 I / O terminal, 5 Transmission line switch, 6 Management device, 7 Monitor,
10 branch line transmission line (normal system), 20 branch line transmission line (standby system), 50 CPU.

Claims (10)

複数系統の伝送路の何れか１つに切替器を介して夫々接続された複数の通信局夫々が所定信号を時系列的に他の通信局へ送信すると共に他の通信局からの前記所定信号を受信し、前記複数の通信局の何れか１つが前記所定信号を所定時間受信できない場合に、前記所定信号を所定時間受信できなかった通信局が前記複数系統の伝送路の何れか１つに自身を接続している切替器へ切替指示を出力して他の系統の伝送路に接続するように切り替えることにより、他の通信局を前記複数系統の伝送路の何れか１つに接続している切替器夫々も前記他の系統の伝送路と接続するように切り替えられる伝送路の冗長化方法において、
前記所定信号に伝送路の切替状態を示す情報を付加し、前記複数系統の伝送路に前記切替器を介して接続された表示手段に前記情報を表示することを特徴とする伝送路の冗長化方法。Each of a plurality of communication stations connected to any one of a plurality of transmission lines via a switch transmits a predetermined signal to another communication station in time series, and the predetermined signal from the other communication station And when any one of the plurality of communication stations cannot receive the predetermined signal for a predetermined time, the communication station that has not received the predetermined signal for a predetermined time is set to one of the transmission lines of the plurality of systems. By switching to connect to another system transmission path by outputting a switching instruction to the switch to which it is connected, other communication stations are connected to any one of the multiple system transmission paths. In the redundancy method of the transmission path that is switched so that each of the switching units that are connected to the transmission path of the other system ,
Information indicating a switching state of a transmission path is added to the predetermined signal, and the information is displayed on display means connected to the transmission lines of the plurality of systems via the switch. Method. 複数系統の伝送路の何れか１つに複数の通信局を夫々接続する複数の切替器夫々が所定信号を時系列的に他の切替器へ送信すると共に他の切替器からの前記所定信号を受信し、前記複数の切替器の何れか１つが前記所定信号を所定時間受信できない場合に、前記所定信号を所定時間受信できなかった切替器が自身に接続されている系統の伝送路を他の系統の伝送路に切り替えることにより、他の切替器夫々も前記他の系統の伝送路と接続するように切り替えられる伝送路の冗長化方法において、
前記所定信号に伝送路の切替状態を示す情報を付加し、前記複数系統の伝送路に前記切替器を介して接続された表示手段に前記情報を表示することを特徴とする伝送路の冗長化方法。Each of a plurality of switching units each connecting a plurality of communication stations to any one of a plurality of transmission lines transmits a predetermined signal to another switching unit in time series and transmits the predetermined signal from the other switching unit. And when any one of the plurality of switching devices cannot receive the predetermined signal for a predetermined time, the switching device that has not received the predetermined signal for the predetermined time is connected to another transmission path of the system connected to itself. By switching to the transmission line of the system, in the redundancy method of the transmission path, each of the other switchers can be switched to connect to the transmission path of the other system .
Information indicating a switching state of a transmission path is added to the predetermined signal, and the information is displayed on display means connected to the transmission lines of the plurality of systems via the switch. Method. 複数系統の伝送路に接続された第１通信局が前記複数系統の伝送路の何れか１つへ所定信号を時系列的に送信し、前記複数系統の伝送路の何れか１つに切替器を介して接続される複数の第２通信局が前記第１通信局からの前記所定信号を受信し、前記複数の第２通信局の何れか１つが前記所定信号を所定時間受信できない場合に、前記所定信号を所定時間受信できなかった第２通信局が前記複数系統の伝送路の何れか１つに自身を接続している切替器へ切替指示を出力して他の系統の伝送路に接続するように切り替えることにより、他の第２通信局を前記複数系統の伝送路の何れか１つに接続している切替器夫々も前記他の系統の伝送路と接続するように切り替えられる伝送路の冗長化方法において、
前記所定信号に伝送路の切替状態を示す情報を付加し、前記複数系統の伝送路に前記切替器を介して接続された表示手段に前記情報を表示することを特徴とする伝送路の冗長化方法。A first communication station connected to a plurality of transmission lines transmits a predetermined signal in time series to any one of the plurality of transmission lines, and a switch is connected to any one of the plurality of transmission lines. When a plurality of second communication stations connected via the first communication station receive the predetermined signal from the first communication station, and any one of the plurality of second communication stations cannot receive the predetermined signal for a predetermined time, The second communication station that has not received the predetermined signal for a predetermined time outputs a switching instruction to a switch that connects itself to any one of the plurality of transmission lines and connects to a transmission line in another system by switching manner to the transmission path switch husband connecting other second communication station to any one of the transmission path of the plurality of systems people also switched to connect a transmission line of the other strains In the redundancy method of
Information indicating a switching state of a transmission path is added to the predetermined signal, and the information is displayed on display means connected to the transmission lines of the plurality of systems via the switch. Method. 複数系統の伝送路に接続された第１通信局が前記複数系統の伝送路の何れか１つへ所定信号を時系列的に送信し、前記複数系統の伝送路の何れか１つに複数の第２通信局を夫々接続する複数の切替器夫々が前記第１通信局からの前記所定信号を受信し、前記複数の切替器の何れか１つが前記所定信号を所定時間受信できない場合に、前記所定信号を所定時間受信できなかった切替器が自身に接続されている系統の伝送路を他の系統の伝送路に接続するように切り替えることにより、他の切替器夫々も前記他の系統の伝送路と接続するように切り替えられる伝送路の冗長化方法において、
前記所定信号に伝送路の切替状態を示す情報を付加し、前記複数系統の伝送路に前記切替器を介して接続された表示手段に前記情報を表示することを特徴とする伝送路の冗長化方法。A first communication station connected to a plurality of transmission lines transmits a predetermined signal in time series to any one of the plurality of transmission lines, and a plurality of transmission lines are connected to any one of the plurality of transmission lines. When each of a plurality of switches connected to the second communication station receives the predetermined signal from the first communication station, and any one of the plurality of switches cannot receive the predetermined signal for a predetermined time, A switch that has not received a predetermined signal for a predetermined time is switched so that the transmission line of the system connected to itself is connected to the transmission line of the other system, so that each of the other switches also transmits the other system. In the redundancy method of the transmission path that can be switched to connect with the path,
Information indicating a switching state of a transmission path is added to the predetermined signal, and the information is displayed on display means connected to the transmission lines of the plurality of systems via the switch. Method. 複数系統の伝送路に接続された複数の通信局夫々が前記複数系統の伝送路夫々を介して同一情報を他の通信局へ送信し、前記複数の通信局夫々が前記複数系統の伝送路夫々を介して同一情報を他の通信局から受信する伝送路の冗長化方法において、
前記送信される情報には他の通信局での保存アドレスを指定する情報が付加されており、前記複数の通信局夫々は前記複数系統の伝送路夫々を介して他の通信局から受信した同一情報を同一のアドレスに格納することを特徴とする伝送路の冗長化方法。Each of a plurality of communication stations connected to a plurality of transmission paths transmits the same information to each of the other communication stations via each of the plurality of transmission paths, and each of the plurality of communication stations is each of the plurality of transmission paths. In the redundancy method of the transmission path for receiving the same information from other communication stations via
Information for designating a storage address in another communication station is added to the transmitted information, and each of the plurality of communication stations receives the same received from another communication station via each of the plurality of transmission lines. A method for redundancy of a transmission path, wherein information is stored at the same address . 複数系統の伝送路と、該複数系統の伝送路の何れか１つに切替指示に応じて選択的に接続する複数の切替器と、夫々の切替器を介して前記複数系統の伝送路の何れか１つと接続されることにより通信を行なう複数の通信局とを含み、
夫々の通信局は、所定信号を時系列的に他の通信局へ送信する送信手段と、他の通信局からの前記所定信号を受信する受信手段と、該受信手段による前記所定信号の受信が所定時間途絶えた場合に前記複数系統の伝送路の何れか１つに自身を接続している切替器へ前記切替指示を出力する出力手段とを備え、前記複数の通信局の何れか１つが前記複数系統の伝送路の何れか１つに自身を接続している切替器を前記切替指示によって他の系統の伝送路と接続するように切り替えた場合に、他の通信局を前記複数系統の伝送路の何れか１つに接続している切替器夫々も前記他の系統の伝送路と接続するように切り替えられるようになしてある伝送路の冗長化システムにおいて、
前記所定信号に伝送路の切替状態を示す情報を付加する付加手段と、
前記通信回線に接続され、前記情報を表示する表示手段と
を備えることを特徴とする伝送路の冗長化システム。A plurality of transmission lines, a plurality of switching units selectively connected to any one of the plurality of transmission lines according to a switching instruction, and any of the plurality of transmission lines via each switching unit A plurality of communication stations that communicate with each other by being connected to
Each communication station includes a transmission unit that transmits a predetermined signal to another communication station in time series, a reception unit that receives the predetermined signal from another communication station, and a reception unit that receives the predetermined signal. Output means for outputting the switching instruction to a switch connected to any one of the transmission lines of the plurality of systems when a predetermined time is interrupted, and any one of the plurality of communication stations is the When a switch that connects itself to any one of a plurality of transmission lines is switched to connect to a transmission line of another system according to the switching instruction, other communication stations transmit the plurality of systems. In the redundant system of transmission lines, each switch connected to any one of the paths can be switched so as to be connected to the transmission path of the other system.
Adding means for adding information indicating a switching state of a transmission path to the predetermined signal;
Display means connected to the communication line for displaying the information;
Redundant system of the transmission path, characterized in that it comprises a. 複数系統の伝送路と、該複数系統の伝送路の何れか１つに選択的に接続する複数の切替器と、夫々の切替器を介して前記複数系統の伝送路の何れか１つと接続されることにより通信を行なう複数の通信局とを含み、
夫々の切替器は、所定信号を時系列的に他の切替器へ送信する送信手段と、他の切替器からの前記所定信号を受信する受信手段とを備え、自身が接続している系統の伝送路を前記受信手段による前記所定信号の受信が所定時間途絶えた場合に他の系統の伝送路に切り替えるように構成されており、前記複数の切替器の何れか１つが自身が接続している系統の伝送路を他の系統の伝送路に切り替えた場合に、他の切替器夫々も前記他の系統の伝送路と接続するように切り替えられるようになしてある伝送路の冗長化システムにおいて、
前記所定信号に伝送路の切替状態を示す情報を付加する付加手段と、
前記通信回線に接続され、前記情報を表示する表示手段と
を備えることを特徴とする伝送路の冗長化システム。A plurality of transmission lines, a plurality of switches selectively connected to any one of the plurality of transmission lines, and any one of the plurality of transmission lines via each switch. A plurality of communication stations that communicate with each other,
Each switch includes a transmission unit that transmits a predetermined signal to another switch in time series, and a reception unit that receives the predetermined signal from the other switch. The transmission path is configured to switch to a transmission path of another system when reception of the predetermined signal by the receiving unit is interrupted for a predetermined time, and any one of the plurality of switches is connected to itself. In the system for redundant transmission lines, when the transmission path of the system is switched to the transmission path of the other system, the other switching units can be switched to connect to the transmission path of the other system.
Adding means for adding information indicating a switching state of a transmission path to the predetermined signal;
Display means connected to the communication line for displaying the information;
Redundant system of the transmission path, characterized in that it comprises a. 複数系統の伝送路と、該複数系統の伝送路に接続されていて何れか１つの系統の伝送路へ所定信号を時系列的に送信する第１通信局と、前記複数系統の伝送路の何れか１つに切替指示に応じて選択的に接続する複数の切替器と、夫々の切替器を介して前記複数系統の伝送路の何れか１つと接続されることにより通信を行なう複数の第２通信局とを含み、
夫々の第２通信局は、前記第１通信局からの前記所定信号を受信する受信手段と、該受信手段による前記所定信号の受信が所定時間途絶えた場合に前記複数系統の伝送路の何れか１つに自身を接続している切替器へ前記切替指示を出力する出力手段とを備え、
前記複数の第２通信局の何れか１つが前記複数系統の伝送路の何れか１つに自身を接続している切替器を前記切替指示によって他の系統の伝送路と接続するように切替えた場合に、他の第２通信局を前記複数系統の伝送路の何れか１つに接続している切替器夫々も前記他の系統の伝送路と接続するように切り替えられるようになしてある伝送路の冗長化システムにおいて、
前記所定信号に伝送路の切替状態を示す情報を付加する付加手段と、
前記通信回線に接続され、前記情報を表示する表示手段と
を備えることを特徴とする伝送路の冗長化システム。A plurality of transmission lines, a first communication station connected to the plurality of transmission lines and transmitting a predetermined signal to any one of the transmission lines in time series, and any of the plurality of transmission lines And a plurality of second switches that perform communication by being connected to any one of the transmission lines of the plurality of systems via the respective switches. Including communication stations,
Each of the second communication stations includes a receiving unit that receives the predetermined signal from the first communication station, and one of the plurality of transmission lines when the reception of the predetermined signal by the receiving unit is interrupted for a predetermined time. Output means for outputting the switching instruction to a switch that connects itself to one;
Any one of the plurality of second communication stations is switched to connect a switch that is connected to any one of the plurality of transmission lines to another transmission line according to the switching instruction. case, there is no such switch husband connecting other second communication station to any one of the transmission path of the plurality of systems people also switched to connect a transmission line of the other strains transmission In the road redundancy system,
Adding means for adding information indicating a switching state of a transmission path to the predetermined signal;
Display means connected to the communication line for displaying the information;
Redundant system of the transmission path, characterized in that it comprises a. 複数系統の伝送路と、該複数系統の伝送路に接続されていて何れか１つの系統の伝送路へ所定信号を時系列的に送信する第１通信局と、前記複数の系統の伝送路の何れか１つに選択的に接続する複数の切替器と、夫々の切替器を介して前記複数系統の伝送路の何れか１つと接続されることにより通信を行なう複数の第２通信局とを含み、
夫々の切替器は、前記第１通信局からの前記所定信号を受信する受信手段を備え、前記受信手段による前記所定信号の受信が所定時間途絶えた場合に自身を接続している系統の伝送路を他の系統の伝送路に切り替えるように構成されており、
前記複数の切替器の何れか１つが自身が接続している系統の伝送路を他の系統の伝送路に切り替えた場合に、他の切替器夫々も前記他の系統の伝送路と接続するように切り替えられるようになしてある伝送路の冗長化システムにおいて、
前記所定信号に伝送路の切替状態を示す情報を付加する付加手段と、
前記通信回線に接続され、前記情報を表示する表示手段と
を備えることを特徴とする伝送路の冗長化システム。A plurality of transmission lines, a first communication station connected to the transmission lines of the plurality of systems and transmitting a predetermined signal to any one of the transmission lines in time series, and the transmission lines of the plurality of systems A plurality of switches selectively connected to any one, and a plurality of second communication stations that perform communication by being connected to any one of the transmission lines of the plurality of systems through the respective switches. Including
Each switch has a receiving means for receiving the predetermined signal from the first communication station, and a transmission path of a system connecting itself when reception of the predetermined signal by the receiving means is interrupted for a predetermined time Is configured to switch to the transmission path of another system,
When any one of the plurality of switches switches the transmission line of the system to which the switch is connected to the transmission line of the other system, each of the other switches is connected to the transmission line of the other system. In a transmission line redundancy system that can be switched to
Adding means for adding information indicating a switching state of a transmission path to the predetermined signal;
Display means connected to the communication line for displaying the information;
Redundant system of the transmission path, characterized in that it comprises a. 複数系統の伝送路と、該複数系統の伝送路に接続された複数の通信局とを含み、前記複数の通信局夫々が前記複数系統の伝送路夫々を介して同一情報を他の通信局へ送信し、前記複数の通信局夫々が前記複数系統の伝送路夫々を介して同一の他の通信局から同一情報を受信すべくなしてある伝送路の冗長化システムにおいて、
前記複数の通信局夫々が前記複数系統の伝送路夫々を介して送信する情報には他の通信局での保存アドレスを指定する情報が付加されており、前記複数の通信局夫々は前記複数系統の伝送路夫々を介して他の通信局から受信した同一情報を同一のアドレスに格納すべくなしてあることを特徴とする伝送路の冗長化システム。Including a plurality of transmission paths and a plurality of communication stations connected to the plurality of transmission paths, wherein each of the plurality of communication stations sends the same information to another communication station via each of the plurality of transmission paths. In the transmission path redundancy system in which each of the plurality of communication stations is to receive the same information from the same other communication station via each of the plurality of transmission paths ,
Information that designates a storage address in another communication station is added to the information that each of the plurality of communication stations transmits via each of the plurality of transmission paths, and each of the plurality of communication stations includes the plurality of systems. A redundant system of transmission lines, characterized in that the same information received from other communication stations via the respective transmission lines is stored at the same address .
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