JP2611285B2 - Line switching device - Google Patents
Line switching deviceInfo
- Publication number
- JP2611285B2 JP2611285B2 JP30768087A JP30768087A JP2611285B2 JP 2611285 B2 JP2611285 B2 JP 2611285B2 JP 30768087 A JP30768087 A JP 30768087A JP 30768087 A JP30768087 A JP 30768087A JP 2611285 B2 JP2611285 B2 JP 2611285B2
- Authority
- JP
- Japan
- Prior art keywords
- line
- switching
- working
- signal
- protection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
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- Detection And Prevention Of Errors In Transmission (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明はシステム予備方式の回線切替装置に係り,特
にビット及び位相の比較により無瞬断切替を行う回線切
替装置に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line switching device of a system backup system, and more particularly to a line switching device that performs instantaneous interruption switching by comparing bits and phases.
第3図は(1+N)無瞬断回線切替システムの構成図
例である。第3図における無瞬断切替の一般的な切替シ
ーケンスは次の通りである。すなわち,送端,受端回線
切替制御回路18,19を通して現用回線の障害により,
予備回線障害の有無及び予備回線の使用状態の確認
を行った後,送端並列動作を行う。次に,受端側にお
いて障害現用回線伝送信号203と予備回線伝送信号204
(伝送信号203,204共に伝送信号201に等価)との比較に
より,ビット及び信号の位相が確認された後,切替(ヒ
ットレス切替)が行われ,障害回線の救済が完了す
る。FIG. 3 is an example of a configuration diagram of a (1 + N) uninterrupted line switching system. The general switching sequence of the hitless switching in FIG. 3 is as follows. That is, through the transmission line and the reception line switching control circuits 18 and 19, the failure of the working line causes
After confirming the presence or absence of the protection line failure and the use state of the protection line, the transmitting end parallel operation is performed. Next, at the receiving end, the faulty working line transmission signal 203 and the protection line transmission signal 204
(The transmission signals 203 and 204 are both equivalent to the transmission signal 201), and after the bit and signal phases are confirmed, switching (hitless switching) is performed, and the repair of the faulty line is completed.
また,一般的な切戻シーケンスは,送端,受端回線切
替制御回路18,19を通して現用回線の障害復旧によ
り,障害復旧した現用回線伝送信号203と予備回線伝送
信号204とのビット及び位相の比較確認後、切戻(ヒッ
トレス切替)が行われる。次に,送端並列の解除に
より予備回線にはパイロット信号が伝送される。受端に
おいてパイロット信号の検出が行われ,切戻しは完了
する。すなわち,回線切替システムは正常な状態に戻
る。In addition, a general switchback sequence is based on the restoration of the working line through the transmission / reception line switching control circuits 18 and 19, and the bit and phase of the working line transmission signal 203 and the protection line transmission signal 204 whose failure has been restored are recovered. After the comparison and confirmation, a switchback (hitless switching) is performed. Next, a pilot signal is transmitted to the protection channel by releasing the transmission end parallel. Pilot signal detection is performed at the receiving end, and switching back is completed. That is, the line switching system returns to a normal state.
第2図は従来の回線切替系の受端側のブロック図であ
る。比較判定回路2は現用回線伝送信号102と予備回線
伝送信号101(現用回線障害時,送端並列により伝送信
号101と102は同一信号)とをビット毎に比較することに
より,現用回線伝送信号102と予備回線伝送信号101との
ビット及び位相の合致判定を行い,判定結果105を出力
する。切替回路3は判定結果105と切替制御信号103とに
より,現用回線伝送信号102と予備回線伝送信号101との
切替を無瞬断で行い,現用回線信号104を出力する。パ
イロット信号検出回路1は予備回線伝送信号101がパイ
ロット信号かどうかを検出し,検出信号106を出力す
る。FIG. 2 is a block diagram on the receiving end side of a conventional line switching system. The comparison and determination circuit 2 compares the working line transmission signal 102 with the protection line transmission signal 101 (when the working line fails, the transmission signals 101 and 102 are the same signal due to the sending end paralleling) on a bit-by-bit basis. A determination is made as to whether the bit and the phase of the signal and the protection line transmission signal 101 match, and a determination result 105 is output. The switching circuit 3 performs switching between the working line transmission signal 102 and the protection line transmission signal 101 without instantaneous interruption based on the determination result 105 and the switching control signal 103, and outputs the working line signal 104. Pilot signal detection circuit 1 detects whether protection channel transmission signal 101 is a pilot signal and outputs detection signal 106.
ここで,比較判定回路2の判定結果には,ビット誤り
なしで切替(ヒットレス切替)を行うため,高い確度が
要求される。例えば,データ通信などでデータ列中に
“1"あるいは“0"が連続しており,フレームパルスのみ
のデータが伝送されるような場合,短いビット比較監視
時間では正しい判定結果が得られない。また,上記のよ
うな場合でビット誤り率が1×10-3程度まで劣化しても
正しい判定結果が得られなければならない。通常,正し
い判定結果を得るため,ビット比較監視時間を長くして
対処している。そのため,比較判定回路では現用・予備
回線間の信号のビット及び位相の合致判定をするのに長
い時間を要する。Here, high accuracy is required for the determination result of the comparison determination circuit 2 because the switching is performed without any bit error (hitless switching). For example, when “1” or “0” is continuous in a data string in data communication or the like and data of only a frame pulse is transmitted, a correct determination result cannot be obtained in a short bit comparison monitoring time. Further, in the above case, even if the bit error rate is degraded to about 1 × 10 −3, a correct judgment result must be obtained. Usually, in order to obtain a correct judgment result, the bit comparison monitoring time is lengthened to cope with the problem. Therefore, it takes a long time for the comparison and determination circuit to determine whether the bit and phase of the signal between the working and protection lines match.
一方,パイロット信号として用いられる信号のパター
ン長は,比較的短いもので済むため,比較判定回路2の
ビット及び位相合致判定時間に比べて,パイロット信号
は短い時間で検出することできる。On the other hand, since the pattern length of the signal used as the pilot signal can be relatively short, the pilot signal can be detected in a shorter time than the bit and phase coincidence determination time of the comparison / determination circuit 2.
上述した従来の回線切替装置は,現用回線の障害復旧
により切替回路の切戻し,送端並列の解除及びパイロッ
ト信号の予備回線伝送が行われ,予備回線受端でのパイ
ロット信号の検出により,回線切替システムは正常状
態,すなわち,次の回線切替が可能な状態であると判断
する。In the conventional line switching apparatus described above, switching back of the switching circuit, release of the parallel connection at the transmitting end, and protection line transmission of the pilot signal are performed by the recovery of the failure of the working line. The switching system determines that it is in a normal state, that is, a state in which the next line can be switched.
しかし,比較判定回路が現用・予備回線間の信号の不
一致を検出する時間は,パイロット信号の検出時間より
も長くかかるため,パイロット信号検出結果の送出時に
は,比較判定回路はまだ信号の不一致を検出できていな
い。障害復旧後,すぐに同一現用回線で障害が発生し,
送端並列が再び行われると,実際にはまだ現用・予備回
線間の信号のビット及び位相が合致していないにもかか
わらず,比較判定回路は切戻し時のビット及び位相合致
という判定結果を保持しているため,回線切替が行われ
てしまう。すなわち,現用・予備回線間の信号のビット
及び位相が合致してない状態で回線切替が行われるた
め,切替時に誤りが発生するという欠点を有している。However, the time required for the comparison and judgment circuit to detect a signal mismatch between the working and protection lines is longer than the detection time of the pilot signal. Therefore, when transmitting the pilot signal detection result, the comparison and judgment circuit still detects the signal mismatch. Not done. Immediately after the failure recovery, a failure occurs on the same working line,
When the sending-end parallel is performed again, the comparison and judgment circuit returns the judgment result that the bit and phase match at the time of switching back, even though the bit and phase of the signal between the working and protection lines do not actually match yet. Since they are held, line switching is performed. That is, line switching is performed in a state where the bit and phase of the signal between the working and protection lines do not match, so that there is a disadvantage that an error occurs at the time of switching.
本発明の回線切替装置は、N個の現用回線に対して予
備回線が設けられている回線切替システムにおいて,受
端側では,現用回線障害時,送端並列により伝送されて
きた現用回線信号と予備回線信号とをビット単位で比較
することにより,現用・予備回線間の信号のビット及び
位相の合致判定を行う比較判定手段と,前記比較判定手
段の判定結果と切替制御信号とにより無瞬断で回線切替
を行う切替手段と,送端並列動作を確認するため予備回
線を伝送されるパイロット信号を検出するパイロット信
号検出手段と,前記切替手段に対して障害発生時の無瞬
断切替シーケンス及び障害復旧時の切戻しシーケンスの
制御を行う受端回線切替制御手段と,前記パイロット信
号検出手段の検出結果を遅延させる遅延手段とを備え,
前記受端回線切替制御手段は,前記遅延手段からの遅延
された前記パイロット信号検出手段の検出結果を受けて
前記切戻しシーケンスが完了したことを判定することを
特徴とする。The line switching apparatus of the present invention is a line switching system in which a protection line is provided for N working lines. A comparison / decision unit for comparing the bit and phase of the signal between the working and protection lines by comparing the protection line signal bit by bit, and an instantaneous interruption by the judgment result of the comparison / judgment unit and the switching control signal Switching means for performing line switching in step S, a pilot signal detecting means for detecting a pilot signal transmitted on a protection line to confirm the parallel operation at the transmitting end, Receiver line switching control means for controlling a switching sequence at the time of failure recovery, and delay means for delaying the detection result of the pilot signal detection means,
The receiving end line switching control means receives the detection result of the pilot signal detecting means delayed from the delay means and determines that the switching back sequence is completed.
次に,本発明の実施例について第1図を参照して説明
する。なお,第2図と共通する部分については同一符号
にて表す。Next, an embodiment of the present invention will be described with reference to FIG. Note that parts common to FIG. 2 are denoted by the same reference numerals.
パイロット信号検出回路1,比較判定回路2,切替回路3
の動作は第2図に示したものと同じである。遅延回路4
はパイロット信号検出結果106をある時間遅延させて検
出信号107を出力する。本実施例ではこのような遅延時
間を設定することにより,現用回線の障害復旧後,予備
回線受端からパイロット信号検出結果が送出される前
に,比較判定回路2が現用・予備回線間の信号の不一致
を検出できるようにしている。したがって,現用回線の
障害復旧により現用回線切替回路の切戻し,送端並列の
解除,パイロット信号の予備回線伝送,予備回線受端か
らパイロット信号検出結果の送出が行われて,回線切替
システムが正常状態に戻ったときには,比較判定回路2
は現用・予備回線間の信号の不一致を検出している。す
なわち,予備回線受端からパイロット信号検出結果が送
出されたときには,比較判定回路2が切戻し時の位相合
致の判定結果を保持していることがない。このことによ
り,障害復旧後すぐにまた同一現用回線で障害が発生し
て送端並列が行われても,現用・予備回線間の信号のビ
ット及び位相が合致するまでは回線切替は行われない。
したがって,本発明によれば障害復旧後,すぐにまた同
一現用回線に障害が発生するような状況においても,無
瞬断切替が可能となる。Pilot signal detection circuit 1, comparison judgment circuit 2, switching circuit 3
Are the same as those shown in FIG. Delay circuit 4
Outputs a detection signal 107 after delaying the pilot signal detection result 106 by a certain time. In the present embodiment, by setting such a delay time, after the failure recovery of the working line, before the pilot signal detection result is transmitted from the protection line receiving end, the comparison and judgment circuit 2 causes the signal between the working and protection lines to be transmitted. Inconsistency can be detected. Therefore, when the failure of the working line is recovered, the working line switching circuit is switched back, the parallel connection of the transmitting end is released, the pilot signal is transmitted to the protection line, and the detection result of the pilot signal is sent from the protection line receiving end. When returning to the state, the comparison and judgment circuit 2
Detects a signal mismatch between the working and protection lines. That is, when the pilot signal detection result is transmitted from the protection line receiving end, the comparison and determination circuit 2 does not hold the determination result of the phase match at the time of switching back. As a result, even if a fault occurs on the same working line immediately after the recovery from the fault and parallel transmission is performed, line switching is not performed until the bit and phase of the signal between the working and protection lines match. .
Therefore, according to the present invention, the instantaneous interruption switching can be performed immediately after the restoration of the failure and also in a situation where a failure occurs in the same working line.
以上説明したように本発明は,パイロット信号検出結
果の送出を遅延させることにより,障害復旧後,回線切
替システムが次の切替シーケンスに移る前に,比較判定
回路は必ず現用・予備回線間の信号の不一致を検出でき
るので,障害復旧後,すぐにまた同一現用回線で障害が
発生するような状況下でも,現用・予備回線間の信号の
ビット及び位相が合致する前に誤って回線切替を行うこ
とがなく,無瞬断で回線切替ができるという効果があ
る。As described above, according to the present invention, by delaying the transmission of the pilot signal detection result, after the failure recovery, before the line switching system shifts to the next switching sequence, the comparison and judgment circuit always makes a signal between the working and protection lines. Can be detected immediately after recovery from a failure, even if the failure occurs on the same working line immediately before the bit and phase of the signal between the working and protection lines match. There is an effect that line switching can be performed without interruption without interruption.
第1図は本発明の一実施例のブロック図,第2図は従来
例の回線切替系の受端側のブロック図,第3図は(1+
N)無瞬断回線切替システムの構成図である。 1……パイロット信号検出回路,2……比較判定回路,3…
…切替回路,4……遅延回路,11……送端切替回路,12……
多重化回路,13……回線監視回路,14……分離回路,15…
…ヒットレス切替回路,16……パイロット信号発生回路,
17……パイロット信号検出回路,18……送端回路切替制
御回路,19……受端回線切替制御回路。FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a block diagram of a receiving side of a conventional line switching system, and FIG.
1 is a configuration diagram of a non-interruptible line switching system. 1 ... Pilot signal detection circuit, 2 ... Comparison circuit, 3 ...
... Switching circuit, 4 ... Delay circuit, 11 ... Sending-end switching circuit, 12 ...
Multiplexing circuit, 13 …… Line monitoring circuit, 14 …… Demultiplexing circuit, 15…
… Hitless switching circuit, 16 …… Pilot signal generation circuit,
17 ... Pilot signal detection circuit, 18 ... Sending-end circuit switching control circuit, 19 ... Reception-end line switching control circuit.
Claims (1)
が設けられている回線切替システムにおいて,受端側で
は,現用回線障害時,送端並列により伝送されてきた現
用回線信号と予備回線信号とをビット単位で比較するこ
とにより,現用・予備回線間の信号のビット及び位相の
合致判定を行う比較判定手段と,前記比較判定手段の判
定結果と切替制御信号とにより無瞬断で回線切替を行う
切替手段と,送端並列動作を確認するため予備回線を伝
送されるパイロット信号を検出するパイロット信号検出
手段と,前記切替手段に対して障害発生時の無瞬断切替
シーケンス及び障害復旧時の切戻しシーケンスの制御を
行う受端回線切替制御手段と,前記パイロット信号検出
手段の検出結果を遅延させる遅延手段とを備え,前記受
端回線切替制御手段は,前記遅延手段からの遅延された
前記パイロット信号検出手段の検出結果を受けて前記切
戻しシーケンスが完了したことを判定することを特徴と
する回線切替装置。In a line switching system in which a protection line is provided for N (≧ 1) working lines, at the receiving end, when the working line fails, the working line signal transmitted by the transmitting end parallel. Comparing means for comparing the bit and the phase of the signal between the working and protection lines by comparing the protection line signal with the protection line signal on a bit-by-bit basis. Switching means for performing line switching upon disconnection, pilot signal detecting means for detecting a pilot signal transmitted on a protection line for confirming the parallel operation at the transmitting end, and non-instantaneous interruption switching sequence when a failure occurs for the switching means. And a delay circuit for delaying a detection result of the pilot signal detecting means, the receiving line switching control means for controlling a switching sequence at the time of failure recovery. Is line switching apparatus characterized by determining that the failback sequence receives the detection result of the delayed said pilot signal detecting means from said delay means is completed.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP30768087A JP2611285B2 (en) | 1987-12-07 | 1987-12-07 | Line switching device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP30768087A JP2611285B2 (en) | 1987-12-07 | 1987-12-07 | Line switching device |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH01149634A JPH01149634A (en) | 1989-06-12 |
JP2611285B2 true JP2611285B2 (en) | 1997-05-21 |
Family
ID=17971943
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP30768087A Expired - Lifetime JP2611285B2 (en) | 1987-12-07 | 1987-12-07 | Line switching device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2611285B2 (en) |
-
1987
- 1987-12-07 JP JP30768087A patent/JP2611285B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPH01149634A (en) | 1989-06-12 |
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