JP3722758B2

JP3722758B2 - Optical communication network, optical node, and optical wavelength path setting method

Info

Publication number: JP3722758B2
Application number: JP2002025696A
Authority: JP
Inventors: 直明山中; 英司大木; 岡本　　聡; 伸昭松浦
Original assignee: Nippon Telegraph and Telephone Corp; NTT Inc USA
Current assignee: NTT Inc; NTT Inc USA
Priority date: 2002-02-01
Filing date: 2002-02-01
Publication date: 2005-11-30
Anticipated expiration: 2022-02-01
Also published as: JP2003229891A

Description

【０００１】
【発明の属する技術分野】
本発明はＲＳＶＰ(Resource Reservation Protocol)による光通信に利用する。特に、光波長選択技術に関する。
【０００２】
【従来の技術】
従来のＲＳＶＰにおける波長選択の動作を図７に示す。シグナリング用のＲＳＶＰはリンクバイリンクで波長を選択する。光ノードＡでは、空波長λ１〜λ４の波長のうち、ランダムもしくは、若番のλ１を使用し、光ノードＢへ接続する。光ノードＢでは、できるだけ波長変換を使わないために、同じ波長λ１を探し、たまたま空いていた波長λ１を接続する。
【０００３】
一方、光ノードＣでは、あいにく空波長はλ３〜λ５であるため、いかなる波長を選択しても、波長変換が必要となる。これらの結果、波長リレーとしてはλ１→λ１→λ３となり、光ノードＣでは波長変換を必要とする。
【０００４】
【発明が解決しようとする課題】
従来の波長選択は、発側の光ノードから着側の光ノードに向けて各光ノードが自律的に空波長を選択している。したがって、発側の光ノードが如何なる波長を選択すれば、着側の光ノードまでの経路で最も波長変換数を減らすことができるかといった考慮は全く行われない。例えば、図７の例では、発側の光ノードが波長λ３を選択していれば、λ３→λ３→λ３の波長リレーとなり、一切の波長変換を必要としない。しかし、従来は、このような波長選択を意図的に行うことはできない。
【０００５】
本発明は、このような背景に行われたものであって、波長変換数を最も少なくした波長選択を行い、伝送効率の良い波長リレーを作成することができる光通信ネットワークおよび光ノードおよびプログラムおよび記録媒体および光波長パス設定方法を提供することを目的とする。
【０００６】
【課題を解決するための手段】
本発明は、発側の光ノードと、この発側の光ノードと着側の光ノードとの間の経路に含まれる複数の光ノードとが空波長情報を互いに交換し合い、その空波長の中から最も波長変換数の少ない波長を選択することにより、伝送効率の良い波長リレーを作成することを特徴とする。さらに、どうしても波長変換が必要である場合には、その波長変換箇所が３Ｒ(Reshaping/Retiming/Regenerating)処理などの光信号をいったん電気信号に変換する処理を必要とする光ノードと一致するようにし、波長変換に伴う伝送効率の低下を極力回避することができる。
【０００７】
本明細書における発側の光ノードおよび着側の光ノードとは、データ転送に先立ってパス設定のためのリクエストを送出する側の光ノードを発側の光ノードといい、このリクエストの終端先となる光ノードを着側の光ノードという。パス設定後におけるデータ転送の際には、発側の光ノードまたは着側の光ノードのいずれもがデータ発信元またはデータ受信先になることができる。また、設定されたパスは、単方向パスであっても双方向パスであってもよい。
【０００８】
すなわち、本発明の第一の観点は、光ノードと、この光ノード間を相互に接続する波長多重されたリンクとを備えた光通信ネットワークであって、本発明の特徴とするところは、発側の光ノードは、自光ノードと着側の光ノードとの間の経路に含まれる光ノードの空波長情報を収集するパケットを生成する手段を備え、前記経路に含まれる光ノードは、自光ノードの空波長情報を前記パケットに書込んで前記着側の光ノードに向けて転送する手段を備え、前記着側の光ノードは、前記パケットに書込まれた空波長情報に基づき前記経路における最も波長変換数の少ない空波長を選択する手段と、この選択する手段の選択結果を前記経路に含まれる光ノードにそれぞれ通知する手段とを備え、前記経路に含まれる光ノードは、それぞれ前記通知する手段により通知された空波長情報に基づき波長を設定する手段を備えたところにある。
【０００９】
前記経路に含まれる光ノードは、空波長情報を前記パケットに書き込む際に、当該空波長を前記通知する手段による通知が行われるまでの間、空波長のまま保留する手段を備えることもできる。
【００１０】
これによれば、空波長情報を収集している間に、その空波長の状況が変化してしまうことを回避でき、空波長情報の信頼度を高めることができる。
【００１１】
前記選択する手段は、前記経路内に光信号をいったん電気信号に変換する処理を要する前記光ノードを含むときには、当該光ノードを波長変換を行う前記光ノードの候補とする手段を備えることが望ましい。
【００１２】
これによれば、３Ｒ処理のような光信号をいったん電気信号に変換する処理を行う光ノードでついでに波長変換を行うことができるため、波長変換に伴う伝送効率の低下を極力回避することができる。
【００１３】
本発明の第二の観点は光ノードであって、本発明の特徴とするところは、光ノードと、この光ノード間を相互に接続する波長多重されたリンクとを備えた光通信ネットワークに適用され、発側の光ノードとして、自己と着側の光ノードとの間の経路に含まれる光ノードの空波長情報を収集するパケットを生成する手段を備え、前記経路に含まれる光ノードとして、自己の空波長情報を前記パケットに書込んで前記着側の光ノードに向けて転送する手段を備え、前記着側の光ノードとして、前記パケットに書込まれた空波長情報に基づき前記経路における最も波長変換数の少ない空波長を選択する手段と、この選択する手段の選択結果を前記経路に含まれる光ノードにそれぞれ通知する手段とを備え、前記経路に含まれる光ノードとして、前記通知する手段により通知された空波長情報に基づき波長を設定する手段を備えたところにある。
【００１４】
前記経路に含まれる光ノードとして、空波長情報を前記パケットに書き込む際に、当該空波長を前記通知する手段による通知が行われるまでの間、空波長のまま保留する手段を備えることもできる。
【００１５】
前記選択する手段は、前記経路内に光信号をいったん電気信号に変換する処理を要する前記光ノードを含むときには、当該光ノードを波長変換を行う前記光ノードの候補とする手段を備えることが望ましい。
【００１６】
本発明の第三の観点はプログラムであって、本発明の特徴とするところは、情報処理装置にインストールすることにより、その情報処理装置に、光通信ネットワークに適用される光ノードに相応する機能として、発側の光ノードに相応する機能として、自己と着側の光ノードとの間の経路に含まれる光ノードの空波長情報を収集するパケットを生成する機能を実現させ、前記経路に含まれる光ノードとして、自己の空波長情報を前記パケットに書込んで前記着側の光ノードに向けて転送する機能を実現させ、前記着側の光ノードに相応する機能として、前記パケットに書込まれた空波長情報に基づき前記経路における最も波長変換数の少ない空波長を選択する機能と、この選択する機能の選択結果を前記経路に含まれる光ノードにそれぞれ通知する機能とを実現させ、前記経路に含まれる光ノードに相応する機能として、前記通知する機能により通知された空波長情報に基づき波長を設定する機能を実現させるところにある。
【００１７】
前記経路に含まれる光ノードに相応する機能として、空波長情報を前記パケットに書き込む際に、当該空波長を前記通知する機能による通知が行われるまでの間、空波長のまま保留する機能を実現させることもできる。
【００１８】
前記選択する機能として、前記経路内に光信号をいったん電気信号に変換する処理を要する前記光ノードを含むときには、当該光ノードを波長変換を行う前記光ノードの候補とする機能を実現させることが望ましい。
【００１９】
本発明の第四の観点は、本発明のプログラムが記録された前記情報処理装置読取可能な記録媒体である。本発明のプログラムは本発明の記録媒体に記録されることにより、前記情報処理装置は、この記録媒体を用いて本発明のプログラムをインストールすることができる。あるいは、本発明のプログラムを保持するサーバからネットワークを介して直接前記情報処理装置に本発明のプログラムをインストールすることもできる。
【００２０】
これにより、コンピュータ装置等の情報処理装置により、波長変換数を最も少なくした波長選択を行い、伝送効率の良い波長リレーを作成することができる光通信ネットワークおよび光ノードを実現することができる。
【００２１】
本発明の第五の観点は、光ノードと、この光ノード間を相互に接続する波長多重されたリンクとを備えた光通信ネットワークに適用される光波長パス設定方法である。
【００２２】
ここで、本発明の特徴とするところは、発側の光ノードにより、自光ノードと着側の光ノードとの間の経路に含まれる光ノードの空波長情報を収集するパケットを生成し、前記経路に含まれる光ノードにより、自光ノードの空波長情報を前記パケットに書込んで前記着側の光ノードに向けて転送し、前記着側の光ノードにより、前記パケットに書込まれた空波長情報に基づき前記経路における最も波長変換数の少ない空波長を選択し、この選択結果を前記経路に含まれる光ノードにそれぞれ通知し、前記経路に含まれる光ノードは、それぞれ通知された空波長情報に基づき波長を設定するところにある。
【００２３】
前記経路に含まれる光ノードは、空波長情報を前記パケットに書き込む際に、当該空波長を前記通知が行われるまでの間、空波長のまま保留することが望ましい。
【００２４】
前記経路内に光信号をいったん電気信号に変換する処理を要する前記光ノードを含むときには、当該光ノードを波長変換を行う前記光ノードの候補とすることが望ましい。
【００２５】
【発明の実施の形態】
（第一実施例）
本発明第一実施例を図１ないし図３を参照して説明する。図１は第一実施例の光通信ネットワークにおける波長選択手順を説明するための図である。図２は第一実施例の光ノードのブロック構成図である。図３は空波長情報収集用パケットを説明するための図である。
【００２６】
第一実施例は、図１に示すように、光ノードＡ〜Ｄと、この光ノードＡ〜Ｄ間を相互に接続する波長多重されたリンクとを備えた光通信ネットワークであって、第一実施例の特徴とするところは、発側の光ノードＡは、図２に示すように、自光ノードＡと着側の光ノードＤとの間の経路に含まれる光ノードＡ〜Ｃの空波長情報を収集するパケットを生成する情報収集パケット生成部１を備え、前記経路に含まれる光ノードＡ〜Ｃは、それぞれ自光ノードの空波長情報を前記パケットに書込んで着側の光ノードＤに向けて転送する空波長情報書込部２を備え、着側の光ノードＤは、前記パケットに書込まれた空波長情報に基づき前記経路における最も波長変換数の少ない空波長を選択する波長選択部３と、この波長選択部３の選択結果を前記経路に含まれる光ノードＡ〜Ｃにそれぞれ通知する波長情報通知部４とを備え、前記経路に含まれる光ノードＡ〜Ｃは、それぞれ波長情報通知部４により通知された空波長情報に基づき波長を設定する波長設定部５を備えたところにある。
【００２７】
なお、本実施例では、説明をわかりやすくするために、発側の光ノードＡ、着側の光ノードＤ、中継の光ノードＢ、Ｃとしてそれぞれ異なる構成であるかのように説明するが、実際には、同じ構成の光ノードが自己の役割に応じてこれらの光ノードの構成を実現する。図３に空波長収集用パケットのフォーマットを示す。
【００２８】
次に、第一実施例の光ノードの動作を説明する。発側の光ノードＡがデータ転送を行うときには、データ転送に先立って波長リレーを作成する。本実施例では、光ノードＡの情報収集パケット生成部１により情報収集用パケットが生成される。このとき、光ノードＡの空波長情報書込部２は、情報収集用パケットに光ノードＡにおける空波長情報を書込み光ノードＢに転送する。図１の例では、光ノードＡにおける空波長はλ１〜λ４である。
【００２９】
光ノードＢの空波長情報書込部２が光ノードＡからの情報収集用パケットを受け取ると、光ノードＢにおける空波長情報を書込み光ノードＣに転送する。図１の例では、光ノードＢにおける空波長はλ１〜λ３である。同様に、光ノードＣでも情報収集用パケットに光ノードＣにおける空波長情報を書込み光ノードＤに転送する。図１の例では、光ノードＣにおける空波長はλ３〜λ５である。
【００３０】
光ノードＤの波長選択部３が情報収集用パケットを受け取ると、そこに書込まれた光ノードＡ〜Ｃの空波長情報を読み取り、波長選択を行う。この波長選択は、できるだけ少ない波長変換数により波長を選択するというポリシによって行われる。これにより波長λ３が選択される。
【００３１】
波長選択部３により選択された波長λ３の情報は、波長情報通知部４から設定波長情報伝達用パケットに書込まれて発側の光ノードＡに向けて送出される。これには、ＲＳＶＰにおける通常のシグナリングパケットが用いられる。この設定波長情報伝達用パケットを受け取った光ノードＡ〜Ｃの波長設定部５は、光ノードＡから光ノードＤに向かうデータを伝送するための波長としてそれぞれλ３を設定する。これにより、光ノードＡから光ノードＤまで波長変換を行うことなく、効率の良いデータ伝送が行われる。図２の例ではλ３のみの波長リレーにより、光ノードＡからＤへの単方向パスが設定される。
【００３２】
（第二実施例）
本発明第二実施例を図５を参照して説明する。図５は第二実施例の光ノードのブロック構成図である。第二実施例の光通信ネットワークでは、発側の光ノードＡから着側の光ノードＤに至る経路に含まれる光ノードＡ〜Ｃは、空波長情報を情報収集用パケットに書き込む際に、書込んだ当該空波長を波長情報通知部４から設定波長情報伝達用パケットによる通知が行われるまでの間、空波長のまま保留する空波長保留部６を備える。これにより、空波長情報収集期間中に空波長の状況が変化してしまうことを回避し、空波長情報の信頼性を向上させ、当該空波長が他のコネクションと重複して使用されることを防ぐ。
【００３３】
（第三実施例）
本発明第三実施例を図６を参照して説明する。図６は第三実施例の動作を示すフローチャートである。第三実施例の光通信ネットワークでは、波長選択部３は、経路内に光信号をいったん電気信号に変換する処理を要する光ノードを含むときには、当該光ノードを波長変換を行う候補とする。
【００３４】
すなわち、光通信ネットワークは、光ファイバの分散や、スイッチ等によりロスが生じる。そのために、無制限に無中継な伝送区間を増やすことはできず、ある一定段数毎に波長変換もしくは少なくとも３Ｒ処理が必要である。そのため波長変換をどこかで入れる必要がある場合は、図６のフローにあるように、無中継不可能な場所を１つの候補とする。このことにより、効率的な波長変換を実現できる。
【００３５】
（第四実施例）
本実施例の光ノードは情報処理装置であるコンピュータ装置により実現することができる。すなわち、コンピュータ装置にインストールすることにより、そのコンピュータ装置に、光通信ネットワークに適用される第一実施例の光ノードに相応する機能として、発側の光ノードＡに相応する機能として、自己と着側の光ノードＤとの間の経路に含まれる光ノードＡ〜Ｃの空波長情報を収集するパケットを生成する情報収集パケット生成部１に相応する機能を実現させ、前記経路に含まれる光ノードＡ〜Ｃに相応する機能として、自己の空波長情報を前記パケットに書込んで着側の光ノードＤに向けて転送する空波長情報書込部２に相応する機能を実現させ、着側の光ノードＤに相応する機能として、前記パケットに書込まれた空波長情報に基づき前記経路における最も波長変換数の少ない空波長を選択する波長選択部３に相応する機能と、この波長選択部３の選択結果を前記経路に含まれる光ノードＡ〜Ｃにそれぞれ通知する波長情報通知部４に相応する機能とを実現させ、前記経路に含まれる光ノードＡ〜Ｃに相応する機能として、波長情報通知部４により通知された空波長情報に基づき波長を設定する波長設定部５に相応する機能を実現させるプログラムをコンピュータ装置にインストールすることにより、そのコンピュータ装置を第一実施例の光ノードに相応する装置とすることができる。
【００３６】
さらに、前記経路に含まれる光ノードＡ〜Ｃに相応する機能として、空波長情報を前記パケットに書き込む際に、当該空波長を波長情報通知部４による通知が行われるまでの間、空波長のまま保留する空波長保留部６に相応する機能を実現させるプログラムをコンピュータ装置にインストールすることにより、そのコンピュータ装置を第二実施例の光ノードに相応する装置とすることができる。
【００３７】
さらに、波長選択部３に相応する機能として、前記経路内に光信号をいったん電気信号に変換する処理を要する光ノードを含むときには、当該光ノードを波長変換を行う光ノードの候補とする機能を実現させるプログラムをコンピュータ装置にインストールすることにより、そのコンピュータ装置を第三実施例の光ノードに相応する装置とすることができる。
【００３８】
本実施例のプログラムは本実施例の記録媒体に記録されることにより、コンピュータ装置は、この記録媒体を用いて本実施例のプログラムをインストールすることができる。あるいは、本実施例のプログラムを保持するサーバからネットワークを介して直接コンピュータ装置に本実施例のプログラムをインストールすることもできる。
【００３９】
これにより、コンピュータ装置により、波長変換数を最も少なくした波長選択を行い、伝送効率の良い波長リレーを作成することができる光通信ネットワークおよび光ノードを実現することができる。
【００４０】
【発明の効果】
以上説明したように、本発明によれば、波長変換数を最も少なくした波長選択を行い、伝送効率の良い波長リレーを作成することができる。
【図面の簡単な説明】
【図１】第一実施例の光通信ネットワークの波長選択手順を説明するための図。
【図２】第一実施例の光通信ネットワークの光ノードのブロック構成図。
【図３】本実施例の光波長収集用パケットを説明するための図。
【図４】第二実施例の光通信ネットワークの波長選択手順を説明するための図。
【図５】第二実施例の光通信ネットワークの光ノードのブロック構成図。
【図６】第三実施例の動作を示すフローチャート。
【図７】従来の波長選択手順を説明するための図。
【符号の説明】
１情報収集パケット生成部
２空波長情報書込部
３波長選択部
４波長情報通知部
５波長設定部
６空波長保留部[0001]
BACKGROUND OF THE INVENTION
The present invention is used for optical communication by RSVP (Resource Reservation Protocol). In particular, it relates to an optical wavelength selection technique.
[0002]
[Prior art]
The operation of wavelength selection in the conventional RSVP is shown in FIG. RSVP for signaling selects wavelengths on a link-by-link basis. In the optical node A, a random or young number λ1 is used among the wavelengths of the sky wavelengths λ1 to λ4, and the optical node A is connected to the optical node B. In the optical node B, in order not to use wavelength conversion as much as possible, the same wavelength λ1 is searched, and the wavelength λ1 that happens to be free is connected.
[0003]
On the other hand, in the optical node C, unfortunately, since the sky wavelengths are λ3 to λ5, wavelength conversion is required no matter what wavelength is selected. As a result, the wavelength relay becomes λ1 → λ1 → λ3, and the optical node C requires wavelength conversion.
[0004]
[Problems to be solved by the invention]
In the conventional wavelength selection, each optical node autonomously selects an empty wavelength from the originating optical node toward the terminating optical node. Therefore, no consideration is given as to what wavelength the originating optical node selects, so that the number of wavelength conversions can be reduced most in the route to the terminating optical node. For example, in the example of FIG. 7, if the source optical node selects the wavelength λ3, the wavelength relay becomes λ3 → λ3 → λ3, and no wavelength conversion is required. However, conventionally, such wavelength selection cannot be performed intentionally.
[0005]
The present invention has been made in such a background, and performs an optical communication network, an optical node, and a program capable of selecting a wavelength with the smallest number of wavelength conversions and creating a wavelength relay with a high transmission efficiency. An object is to provide a recording medium and an optical wavelength path setting method.
[0006]
[Means for Solving the Problems]
In the present invention, the optical wavelength on the originating side and a plurality of optical nodes included in the path between the optical node on the originating side and the optical node on the destination side exchange the empty wavelength information with each other. A wavelength relay with good transmission efficiency is created by selecting a wavelength with the smallest number of wavelength conversions from among them. In addition, if wavelength conversion is absolutely necessary, the wavelength conversion point should match the optical node that needs to convert the optical signal such as 3R (Reshaping / Retiming / Regenerating) processing into an electrical signal. Thus, it is possible to avoid a decrease in transmission efficiency due to wavelength conversion as much as possible.
[0007]
In the present specification, the originating optical node and the terminating optical node are referred to as an originating optical node that transmits a path setting request prior to data transfer, and the termination destination of this request. The optical node that becomes is called the destination optical node. When transferring data after setting a path, either the originating optical node or the terminating optical node can be a data source or a data destination. The set path may be a unidirectional path or a bidirectional path.
[0008]
In other words, a first aspect of the present invention is an optical communication network comprising an optical node and a wavelength-multiplexed link that interconnects the optical nodes. The optical node on the side includes means for generating a packet for collecting the empty wavelength information of the optical node included in the path between the own optical node and the destination optical node, and the optical node included in the path Means for writing the empty wavelength information of the optical node into the packet and transferring it toward the optical node on the destination side, the optical node on the destination side receiving the path based on the empty wavelength information written in the packet; Means for selecting an empty wavelength having the smallest number of wavelength conversions in the optical system, and means for notifying the optical nodes included in the path of the selection results of the means for selecting, respectively, notification There is to provided with a means for setting the wavelength based on the notified empty wavelength information by that means.
[0009]
The optical node included in the path may be provided with a means for holding the empty wavelength as it is until the empty wavelength information is written in the packet until the notification by the notifying means is performed.
[0010]
According to this, it is possible to avoid the situation of the sky wavelength from being changed while collecting the sky wavelength information, and it is possible to increase the reliability of the sky wavelength information.
[0011]
Preferably, the means for selecting includes means for setting the optical node as a candidate for the optical node that performs wavelength conversion when the optical node that requires processing for once converting an optical signal into an electrical signal is included in the path. .
[0012]
According to this, since wavelength conversion can be subsequently performed at an optical node that performs processing for once converting an optical signal such as 3R processing into an electrical signal, it is possible to avoid a decrease in transmission efficiency due to wavelength conversion as much as possible. .
[0013]
A second aspect of the present invention is an optical node, and the feature of the present invention is that it is applied to an optical communication network including an optical node and a wavelength-multiplexed link that interconnects the optical nodes. And a means for generating a packet for collecting empty wavelength information of the optical node included in the path between the optical node on the receiving side and the optical node on the destination side as the optical node on the originating side, Means for writing its own empty wavelength information in the packet and transferring it toward the destination optical node, and as the destination optical node, in the path based on the empty wavelength information written in the packet Means for selecting an empty wavelength having the smallest number of wavelength conversions, and means for notifying the optical node included in the path of the selection result of the means for selecting, respectively, as the optical node included in the path, There is to provided with a means for setting the wavelength on the basis of the air wavelength information notified by means of knowledge.
[0014]
As the optical node included in the path, when writing the empty wavelength information in the packet, it is possible to provide a means for holding the empty wavelength as it is until the notification of the empty wavelength is performed by the notifying means.
[0015]
Preferably, the means for selecting includes means for setting the optical node as a candidate for the optical node that performs wavelength conversion when the optical node that requires processing for once converting an optical signal into an electrical signal is included in the path. .
[0016]
A third aspect of the present invention is a program, and a feature of the present invention is that a function corresponding to an optical node applied to an optical communication network is installed in the information processing apparatus by installing the information processing apparatus. As a function corresponding to the optical node on the originating side, a function for generating a packet for collecting the empty wavelength information of the optical node included in the path between itself and the destination optical node is realized and included in the path. As an optical node, the function of writing its own empty wavelength information in the packet and transferring it to the destination optical node is realized, and the function corresponding to the destination optical node is written in the packet. The function of selecting the sky wavelength with the smallest number of wavelength conversions in the path based on the information of the empty wavelength and the selection result of the function to be selected are respectively passed to the optical nodes included in the path. To realize the functions and that, as a function corresponding to the light nodes included in the path, there is to be realized the function of setting the wavelength on the basis of the air wavelength information notified by the function of the notification.
[0017]
As a function corresponding to the optical node included in the path, when writing empty wavelength information to the packet, a function to hold the empty wavelength until it is notified by the function of notifying the empty wavelength is realized. It can also be made.
[0018]
As the function to be selected, when the optical node that requires processing for once converting an optical signal into an electrical signal is included in the path, a function of setting the optical node as a candidate for the optical node that performs wavelength conversion is realized. desirable.
[0019]
A fourth aspect of the present invention is the information processing apparatus-readable recording medium on which the program of the present invention is recorded. By recording the program of the present invention on the recording medium of the present invention, the information processing apparatus can install the program of the present invention using this recording medium. Alternatively, the program of the present invention can be directly installed in the information processing apparatus via a network from a server holding the program of the present invention.
[0020]
Accordingly, an optical communication network and an optical node capable of performing wavelength selection with the smallest number of wavelength conversions and creating a wavelength relay with good transmission efficiency by an information processing apparatus such as a computer apparatus can be realized.
[0021]
A fifth aspect of the present invention is an optical wavelength path setting method applied to an optical communication network including an optical node and a wavelength-multiplexed link that interconnects the optical nodes.
[0022]
Here, the feature of the present invention is that a packet that collects empty wavelength information of an optical node included in a path between the own optical node and a destination optical node is generated by the optical node on the outgoing side, By the optical node included in the path, the empty wavelength information of the own optical node is written in the packet and transferred to the destination optical node, and is written in the packet by the destination optical node. Based on the sky wavelength information, the sky wavelength with the smallest number of wavelength conversions in the path is selected, the selection result is notified to each optical node included in the path, and the optical node included in the path is notified to each of the notified sky nodes. The wavelength is set based on the wavelength information.
[0023]
When the optical node included in the path writes the empty wavelength information in the packet, it is desirable to hold the empty wavelength as it is until the notification is performed.
[0024]
When the optical node that requires processing for converting an optical signal into an electrical signal in the path is included, it is preferable that the optical node be a candidate for the optical node that performs wavelength conversion.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
(First Example)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram for explaining a wavelength selection procedure in the optical communication network of the first embodiment. FIG. 2 is a block diagram of the optical node of the first embodiment. FIG. 3 is a diagram for explaining an empty wavelength information collection packet.
[0026]
As shown in FIG. 1, the first embodiment is an optical communication network including optical nodes A to D and wavelength-multiplexed links that interconnect the optical nodes A to D. The feature of the embodiment is that, as shown in FIG. 2, the optical node A on the outgoing side is empty of the optical nodes A to C included in the path between the own optical node A and the destination optical node D. An information collection packet generation unit 1 for generating a packet for collecting wavelength information is provided, and each of the optical nodes A to C included in the path writes the empty wavelength information of the own optical node in the packet, and the destination optical node The destination optical node D selects the empty wavelength with the smallest number of wavelength conversions in the path based on the empty wavelength information written in the packet. The wavelength selector 3 and the selection result of the wavelength selector 3 are Wavelength information notifying unit 4 for notifying each of the optical nodes A to C included in the optical node, and the optical nodes A to C included in the path each have a wavelength based on the empty wavelength information notified by the wavelength information notifying unit 4. The wavelength setting unit 5 for setting is provided.
[0027]
In this embodiment, in order to make the explanation easy to understand, the explanation will be made as if the source optical node A, the destination optical node D, and the relay optical nodes B and C have different configurations. Actually, optical nodes having the same configuration realize the configurations of these optical nodes according to their roles. FIG. 3 shows the format of the empty wavelength collection packet.
[0028]
Next, the operation of the optical node of the first embodiment will be described. When the originating optical node A performs data transfer, a wavelength relay is created prior to data transfer. In this embodiment, an information collection packet is generated by the information collection packet generator 1 of the optical node A. At this time, the empty wavelength information writing unit 2 of the optical node A transfers the empty wavelength information in the optical node A to the writing optical node B in the information collection packet. In the example of FIG. 1, the sky wavelengths in the optical node A are λ1 to λ4.
[0029]
When the empty wavelength information writing unit 2 of the optical node B receives the information collection packet from the optical node A, the empty wavelength information in the optical node B is transferred to the writing optical node C. In the example of FIG. 1, the sky wavelengths in the optical node B are λ1 to λ3. Similarly, in the optical node C, the empty wavelength information in the optical node C is transferred to the writing optical node D in the information collecting packet. In the example of FIG. 1, the sky wavelengths in the optical node C are λ3 to λ5.
[0030]
When the wavelength selection unit 3 of the optical node D receives the information collection packet, the wavelength selection is performed by reading the empty wavelength information of the optical nodes A to C written therein. This wavelength selection is performed by a policy of selecting a wavelength with the smallest possible number of wavelength conversions. As a result, the wavelength λ3 is selected.
[0031]
Information on the wavelength λ3 selected by the wavelength selection unit 3 is written from the wavelength information notification unit 4 into the set wavelength information transmission packet and transmitted to the optical node A on the transmission side. For this, a normal signaling packet in RSVP is used. The wavelength setting units 5 of the optical nodes A to C that have received this set wavelength information transmission packet set λ3 as a wavelength for transmitting data from the optical node A to the optical node D, respectively. Thereby, efficient data transmission is performed without performing wavelength conversion from the optical node A to the optical node D. In the example of FIG. 2, a unidirectional path from the optical node A to D is set by the wavelength relay of only λ3.
[0032]
(Second embodiment)
A second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram of the optical node of the second embodiment. In the optical communication network of the second embodiment, the optical nodes A to C included in the path from the originating optical node A to the terminating optical node D write the empty wavelength information in the information collecting packet. The empty wavelength hold unit 6 holds the empty wavelength as it is until the wavelength information notification unit 4 notifies the set wavelength information transmission packet using the set wavelength information transmission packet. This avoids the situation of the sky wavelength changing during the sky wavelength information collection period, improves the reliability of the sky wavelength information, and ensures that the sky wavelength is used redundantly with other connections. prevent.
[0033]
(Third embodiment)
A third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a flowchart showing the operation of the third embodiment. In the optical communication network of the third embodiment, when the wavelength selecting unit 3 includes an optical node that needs to convert an optical signal into an electrical signal in the path, the wavelength selecting unit 3 sets the optical node as a candidate for wavelength conversion.
[0034]
That is, in the optical communication network, loss occurs due to dispersion of optical fibers, switches, and the like. For this reason, it is impossible to increase the number of unrelayable transmission sections without limitation, and wavelength conversion or at least 3R processing is required for each certain number of stages. Therefore, when it is necessary to insert wavelength conversion somewhere, as shown in the flow of FIG. 6, a place where no relay is possible is set as one candidate. Thus, efficient wavelength conversion can be realized.
[0035]
(Fourth embodiment)
The optical node of the present embodiment can be realized by a computer device that is an information processing device. That is, when installed in a computer device, the computer device receives itself as a function corresponding to the optical node of the first embodiment applied to the optical communication network and as a function corresponding to the originating optical node A. A function corresponding to the information collection packet generation unit 1 that generates a packet for collecting the empty wavelength information of the optical nodes A to C included in the path to the optical node D on the side is realized, and the optical node included in the path As a function corresponding to A to C, a function corresponding to the empty wavelength information writing unit 2 for writing its own empty wavelength information in the packet and transferring it to the destination optical node D is realized. As a function corresponding to the optical node D, a function corresponding to the wavelength selection unit 3 that selects the empty wavelength with the smallest number of wavelength conversions in the path based on the empty wavelength information written in the packet. And a function corresponding to the wavelength information notifying unit 4 for notifying the optical nodes A to C included in the path of the selection result of the wavelength selecting unit 3, respectively, to the optical nodes A to C included in the path As a corresponding function, a program for realizing a function corresponding to the wavelength setting unit 5 for setting the wavelength based on the empty wavelength information notified by the wavelength information notification unit 4 is installed in the computer device, so that the computer device is first configured. An apparatus corresponding to the optical node of the embodiment can be obtained.
[0036]
Furthermore, as a function corresponding to the optical nodes A to C included in the path, when writing the empty wavelength information to the packet, until the wavelength information notification unit 4 notifies the empty wavelength of the empty wavelength, By installing in the computer device a program that realizes the function corresponding to the empty wavelength holding unit 6 that holds it as it is, the computer device can be made a device corresponding to the optical node of the second embodiment.
[0037]
Further, as a function corresponding to the wavelength selection unit 3, when an optical node that needs to convert an optical signal into an electrical signal is included in the path, the optical node is a candidate for an optical node that performs wavelength conversion. By installing the program to be realized in the computer device, the computer device can be made a device corresponding to the optical node of the third embodiment.
[0038]
By recording the program of the present embodiment on the recording medium of the present embodiment, the computer apparatus can install the program of the present embodiment using this recording medium. Alternatively, the program of this embodiment can be directly installed on the computer device from the server holding the program of this embodiment via the network.
[0039]
Accordingly, it is possible to realize an optical communication network and an optical node capable of selecting a wavelength with the smallest number of wavelength conversions and creating a wavelength relay with good transmission efficiency by a computer device.
[0040]
【The invention's effect】
As described above, according to the present invention, it is possible to perform wavelength selection with the smallest number of wavelength conversions and to create a wavelength relay with good transmission efficiency.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a wavelength selection procedure of an optical communication network according to a first embodiment.
FIG. 2 is a block diagram of an optical node of the optical communication network according to the first embodiment.
FIG. 3 is a diagram for explaining an optical wavelength collection packet according to the present embodiment.
FIG. 4 is a diagram for explaining a wavelength selection procedure of the optical communication network according to the second embodiment.
FIG. 5 is a block diagram of an optical node of the optical communication network according to the second embodiment.
FIG. 6 is a flowchart showing the operation of the third embodiment.
FIG. 7 is a diagram for explaining a conventional wavelength selection procedure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Information collection packet production | generation part 2 Empty wavelength information writing part 3 Wavelength selection part 4 Wavelength information notification part 5 Wavelength setting part 6 Empty wavelength reservation part

Claims

In an optical communication network comprising an optical node and a wavelength-multiplexed link interconnecting the optical nodes,
The originating optical node comprises means for generating a packet that collects the empty wavelength information of the optical node included in the path between the own optical node and the terminating optical node,
The optical node included in the path includes means for writing the empty wavelength information of the own optical node in the packet and transferring it to the optical node on the destination side,
The destination optical node is:
Means for selecting the sky wavelength with the smallest number of wavelength conversions in the path based on the sky wavelength information written in the packet;
Means for notifying the optical node included in the path of the selection result of the means for selecting,
Each of the optical nodes included in the path includes means for setting a wavelength based on sky wavelength information notified by the means for notifying ,
The optical node included in the path includes means for holding the empty wavelength as it is until the empty wavelength information is written in the packet until notification by the notifying means is performed. Optical communication network.

In an optical communication network comprising an optical node and a wavelength-multiplexed link interconnecting the optical nodes,
The originating optical node comprises means for generating a packet that collects empty wavelength information of the optical node included in the path between the own optical node and the terminating optical node, and the optical node included in the path includes: Means for writing the empty wavelength information of the own optical node in the packet and transferring it toward the optical node on the destination side;
The destination optical node is:
Means for selecting the sky wavelength with the smallest number of wavelength conversions in the path based on the sky wavelength information written in the packet;
Means for notifying each of the optical nodes included in the path of the selection result of the means for selecting;
With
Each of the optical nodes included in the path includes means for setting a wavelength based on sky wavelength information notified by the means for notifying,
The means for selecting includes means for setting the optical node as a candidate for the optical node that performs wavelength conversion when the optical node that requires processing for converting an optical signal into an electrical signal in the path is included.
An optical communication network characterized by that .

Applied to an optical communication network comprising an optical node and a wavelength-multiplexed link interconnecting the optical nodes;
Means for generating a packet that collects empty wavelength information of the optical node included in the path between the optical node on the receiving side and the optical node on the destination side as the optical node on the outgoing side;
As an optical node included in the path, it comprises means for writing its own empty wavelength information in the packet and transferring it toward the destination optical node,
Means for selecting the empty wavelength with the smallest number of wavelength conversions in the path based on the empty wavelength information written in the packet as the destination optical node;
Means for notifying each of the optical nodes included in the path of the selection result of the means for selecting;
With
As an optical node included in the path, comprising: means for setting a wavelength based on sky wavelength information notified by the notifying means;
As an optical node included in the path, when writing empty wavelength information in the packet, the optical node includes means for holding the empty wavelength as it is until notification by the means for notifying the empty wavelength is performed.
An optical node characterized by that .

Applied to an optical communication network comprising an optical node and a wavelength-multiplexed link interconnecting the optical nodes;
Means for generating a packet that collects empty wavelength information of the optical node included in the path between the optical node on the receiving side and the optical node on the destination side as the optical node on the outgoing side;
As an optical node included in the path, it comprises means for writing its own empty wavelength information in the packet and transferring it toward the destination optical node,
Means for selecting the empty wavelength with the smallest number of wavelength conversions in the path based on the empty wavelength information written in the packet as the destination optical node;
Means for notifying the optical node included in the path of the selection result of the means for selecting,
As an optical node included in the path, comprising: means for setting a wavelength based on sky wavelength information notified by the notifying means;
The means for selecting comprises means for setting the optical node as a candidate for the optical node that performs wavelength conversion when the optical node that requires processing for converting an optical signal into an electrical signal in the path is included. Characteristic optical node.

By installing the information processing device, the information processing device has a function corresponding to the optical node applied to the optical communication network.
As a function corresponding to the optical node on the originating side, a function for generating a packet for collecting the empty wavelength information of the optical node included in the path between the self and the optical node on the destination side is realized,
As a function corresponding to the optical node included in the path, realize the function of writing its own empty wavelength information in the packet and transferring it to the destination optical node,
As a function corresponding to the destination optical node,
A function of selecting the sky wavelength with the smallest number of wavelength conversions in the path based on the sky wavelength information written in the packet;
A function for notifying the optical node included in the path of the selection result of the function to be selected;
Realized,
As a function corresponding to the optical node included in the path, to realize a function to set the wavelength based on the empty wavelength information notified by the function to notify,
As a function corresponding to the optical node included in the path, when writing empty wavelength information to the packet, a function to hold the empty wavelength until it is notified by the function of notifying the empty wavelength is realized. Make
A program characterized by that .

By installing the information processing device, the information processing device has a function corresponding to the optical node applied to the optical communication network.
As a function corresponding to the optical node on the originating side, a function for generating a packet for collecting the empty wavelength information of the optical node included in the path between the self and the optical node on the destination side is realized,
As a function corresponding to the optical node included in the path, realize the function of writing its own empty wavelength information in the packet and transferring it to the destination optical node,
As a function corresponding to the destination optical node,
A function of selecting the sky wavelength with the smallest number of wavelength conversions in the path based on the sky wavelength information written in the packet;
A function for notifying the optical node included in the path of the selection result of the function to be selected;
Realized,
As a function corresponding to the optical node included in the path, to realize a function to set the wavelength based on the empty wavelength information notified by the function to notify,
When the optical node that requires processing for once converting an optical signal into an electrical signal is included in the path as the function to be selected, a function that makes the optical node a candidate for the optical node that performs wavelength conversion is realized.
A program characterized by that .

The information processing apparatus-readable recording medium on which the program according to claim 5 or 6 is recorded .

In an optical wavelength path setting method applied to an optical communication network including an optical node and a wavelength-multiplexed link that interconnects the optical nodes,
The outgoing optical node generates a packet that collects the empty wavelength information of the optical node included in the path between the own optical node and the incoming optical node,
By the optical node included in the path, the empty wavelength information of the own optical node is written in the packet and transferred to the destination optical node,
With the optical node on the destination side,
Select the sky wavelength with the smallest number of wavelength conversions in the path based on the sky wavelength information written in the packet,
Notifying each optical node included in the route of the selection result,
The optical nodes included in the path set wavelengths based on the notified sky wavelength information,
When the optical node included in the path writes the empty wavelength information in the packet, it holds the empty wavelength as it is until the notification is made.
An optical wavelength path setting method .

In an optical wavelength path setting method applied to an optical communication network including an optical node and a wavelength-multiplexed link that interconnects the optical nodes,
The originating optical node generates a packet that collects the empty wavelength information of the optical node included in the path between the own optical node and the destination optical node, and the optical node included in the path Write the empty wavelength information in the packet and forward it to the destination optical node,
With the optical node on the destination side,
Select the sky wavelength with the smallest number of wavelength conversions in the path based on the sky wavelength information written in the packet,
Notifying each optical node included in the route of the selection result,
The optical nodes included in the path set wavelengths based on the notified sky wavelength information,
When the optical node that requires processing for converting an optical signal into an electrical signal is included in the path, the optical node is set as a candidate for the optical node that performs wavelength conversion.
An optical wavelength path setting method .