CN101043271B - Method, equipment and system for switching optical service signal protection - Google Patents
Method, equipment and system for switching optical service signal protection Download PDFInfo
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- CN101043271B CN101043271B CN2007100742266A CN200710074226A CN101043271B CN 101043271 B CN101043271 B CN 101043271B CN 2007100742266 A CN2007100742266 A CN 2007100742266A CN 200710074226 A CN200710074226 A CN 200710074226A CN 101043271 B CN101043271 B CN 101043271B
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Abstract
The invention suits for field of light communication, it provides a light operation signal protection rearrange method, equipment and system, said method includes following steps: channel-associated marking signal is load to light operation signal at the protection rearrange operation source node; At the protection rearrange operation persistent node, channel-associated marking signal which is load in light operation signal is detected; The detecting result of channel-associated marking signal is as the trigger condition of light operation signal protection rearrange to trigger the light operation signal protection rearrange. The invention proceeds the light operation signal protection rearrange based on the detecting result of channel-associated marking signal or protection spending information ofchannel-associated marking signal, the fault detecting rate and rearrange success rate of light layer and useableness of system are increased, it also can detects whether is there fault joint in operation link, the generation of fault link can be suppressed and increases the efficiency of protection rearrange.
Description
Technical field
The invention belongs to optical communication field, relate in particular to a kind of switching optical service signal protection method, equipment and system.
Background technology
The progress of optical device has greatly promoted the development of optical communication technique, especially wavelength division multiplexing (Wavelength Division Multiplexing, WDM) development of technology.At present, the message capacity that can carry of simple optical fiber is up to bits per second (Tbps) too.In this case, bottom optical network optical fiber line fault or equipment fault often affect a large amount of business, improve network survivability and become the major issue that operator and equipment supplier need pay close attention to day by day.
Network survivability is network still can be kept acceptable quality of service grade during standing network failure and equipment failure a ability.The key technical indexes that characterizes the network survivability performance has fault detect rate, protection to switch success rate, redundancy, recovery rate and recovery time.Fault detect rate is defined as the probability that can detect and locate after the equipment fault.Switch the probability of can successful trigger protection switching after success rate is defined as fault and takes place.Redundancy is defined as in the network ratio of total idle capacity and total work capacity, mainly is that the measurement system can the required extra cost of paying for improving survivability.Recovery rate refer to fault a situation arises down, the ratio of the port number that has recovered and the overall channel number of original inefficacy, or the ratio of the capacity that has recovered and original total inefficacy capacity.Refer to that network is to recover the required consumed time of failure service recovery time.
Different business is different fully to the requirement of failure recovery time.Under the general situation, the ATM of large-scale financial institution and bank is the highest to requirement recovery time of business, generally requires less than 50 milliseconds.Common communication service is higher to the suffertibility of service outage duration, but generally also is no more than 30 minutes.These business are after process switch or router processing, transmit through optical-fiber network.Generally speaking, when transmission network break period was between 50～200 milliseconds, the connection losing probability of the reciprocal exchange of business did not have influence less than 5% substantially for No.7 nation-wide Network and cell relay service.When transmission network increased between 200 milliseconds～2 seconds break period, reciprocal exchange of business losing probability began progressively to rise, and surpassed after 2 seconds, and most circuit switching connection, special line, dial business all will be lost.When transmission network arrives 10 seconds break period, all communication sessions all will be lost connection.If transmission network break period surpassed after 5 minutes, will cause the irrecoverable of the serious obstruction of switch and upper-layer service longer time.
For a long time; time division multiplexing (Time Division Multiplex; TDM) (Synchronous Digital Hierarchy, SDH) defencive function that Self-healing Rings is powerful makes it become commonplace networking mode as main business model and synchronous digital hierarchy.The SDH looped network is supported two-way approach commutative ring (Bidirectional Path Switching Ring; BPSR); unidirectional path switched ring (Unidirectional PathSwitching Ring; UPSR); one-way line commutative ring (Unidirectional Line Switching Ring; ULSR); two fibre circuit commutative rings (Two Fiber Bidirectional Line Switching Ring; 2F-BLSR); four fibre circuit commutative rings (Four Fiber Bidirectional Line Switching Ring; 4F-BLSR) and SNCP (Sub-Network Connection protection, SNCP).Along with being surging forward of metropolitan area bulky grain high band wide data service application, wdm system is progressively by the transmission net of metropolitan area network employing as the bottom.Metro WDM is usually with the networking of looped network form; the UPSR that wdm system simulation SDH equipment provides; BPSR; BLSR; ULSR; protected modes such as SNCP provide similar protected mode: light unidirectional path switched ring (Optical Unidirectional Path Switching Ring; OUPSR); light two-way approach commutative ring (Optical Bidirectional Path Switching Ring; OBPSR); light one-way line commutative ring (Optical Unidirectional Line Switching Ring; OULSR); light bidirectional line switched rings (Optical Bidirectional Line Switching Ring; OBLSR); O-SNCP (Optical Sub-Network Connection protection; OSNCP) and light-channel shared protection (Optical Channel Shared protection Ring, OCh-SPRing).
In light-channel shared protection, need to detect optical service signal in real time and whether produce fault, and determine whether initiating to protect switching according to the fault detect result.At present, whether produce on the fault, generally judge by detecting optical service signal power whether network lost efficacy,, then be considered as service exception, initiate protection and switch if optical service signal power is lower than certain thresholding at the detection optical service signal.
The realization principle of 1+1 light-channel shared protection in Fig. 1 prior art for outstanding its protection philosophy, has been ignored other miscellaneous function unit such as the multiplexer in the wdm system, demodulation multiplexer and image intensifer.The 1+1 light-channel shared protection is that certain wavelength business both transmitted by service aisle (W), transmits by backup path (P) again.At transmitter side, the wavelength signals that laser sends is divided into the duplicate optical service signal of two-way through coupler, sends into operating path and backup path simultaneously.At receiver side, adopt an optical switch to receive the two-way optical service signal simultaneously, by the two-way optical service signal is monitored, select the better optical service signal of one road signal quality to send receiver side to.
The 1+1 Optical Channel Protection belongs to single-ended protection; transmitter side does not need to carry out any operation; no matter normally whether network; transmitter side all is divided into two-way with the optical service signal merit; at receiver side; need monitor the power of two-way optical service signal, and decide which optical service signal meeting selected according to monitored results.As shown in Figure 2; at receiver side; be provided with coupler and power-sensing circuit PIN1 and PIN2 on service aisle and the backup path respectively; the power detection result of the optical service signal of PIN1 and PIN2 is through modulus (Analog toDigital; AD) after the conversion; be directly inputted to protection and switch in the control unit, protection is switched control unit two testing results is compared, and controls the routing of optical switch afterwards.
Above-mentioned detection optical service signal power and with this as judging in the whether normal switching optical service signal protection of optical service signal, be difficult to react the optical service signal actual conditions strictly according to the facts, influence the validity of switching optical service signal protection.At first, often adopt image intensifer in the optical service signal transmission, if image intensifer is introduced excessive noise, the optical service signal power detection can not detect whether noise exceeds standard, (whether Optical Signal to Noise Ratio OSNR) corrupts to unacceptable degree to Optical Signal To Noise Ratio; Secondly, adopt pure optical service signal power detection, and compare the mode of judging whether optical service signal breaks down with a certain thresholding, in the optical service signal loss of power, and when having sealed in too much noise or other on the corresponding light passage with frequency component, the crosstalk energy of this optical channel still is higher than the judgement thresholding, detect and to occur unusually, testing result can't reflect that network has occurred unusually, whether when for example two identical wavelength signals of business mix, it is can't differentiated service available only to rely on power detection; Moreover the network failure protection is switched and is relied on the fault detect condition, and network recovery also relies on the fault detect condition, if the optical service signal of correspondence on crosstalking on the fail operation passage, though network failure is not eliminated, can bring out potential network recovery, cause network recovery unusual; The more important thing is; produce under the application scenario of wrong connection in meetings such as light-channel shared protections; only rely on the optical service signal power detection and can't realize wrong connection compacting; and adopt whole net to dispose the mode of wrong connection pressing table; it is mutual to introduce too much node; increase the implementation complexity and the difficulty of protection, increased the realization cost.
Though by wavelength conversion unit (Optical Transponder Unit, OTU) optical service signal that certain optical channel carried is carried out can evading the shortcoming that above-mentioned optical service signal power detection is brought with the road monitoring, but optical service signal only is adapted at being provided with service source, the destination node of wavelength conversion unit with the road monitoring, still can't monitor optical service signal at intermediate node, and for optical multiplexing section signal (OpticalMultiplex Section, OMS), the optical service signal that still can't be carried the multichannel wavelength is simultaneously monitored.Simultaneously, when adopting the OTU mode that optical service signal is carried out monitor with the road, the converting unit among the OTU is comparatively expensive, and the realization cost is higher.
Summary of the invention
The purpose of the embodiment of the invention is to provide a kind of switching optical service signal protection method; be intended to solve in the existing switching optical service signal protection; with the testing conditions of optical service signal power detection, be difficult to react strictly according to the facts the problem of optical service signal actual conditions as switching optical service signal protection.
The embodiment of the invention is achieved in that a kind of switching optical service signal protection method, and described method comprises the steps:
Switch the service source node in protection, will be to optical service signal with the line signal loading, describedly be loaded in the optical service signal by frequency division multiplexing, time division multiplexing, code division multiplexing or its combination in any mode with the line signal, when loading with the line signal by time division multiplexing mode, reserve predetermined slot time during time slot allocation, load(ing) point does not load with the line signal in slot time;
Switch professional destination node in protection, to detecting of loading in the optical service signal with the line signal;
With with the line signal detecting result as the switching optical service signal protection trigger condition, trigger switching optical service signal protection.
Another purpose of the embodiment of the invention is to provide a kind of optical communication equipment, and described equipment comprises:
With line signal loading unit, being used for will be with the line signal loading to optical service signal, describedly be loaded in the optical service signal by frequency division multiplexing, time division multiplexing, code division multiplexing or its combination in any mode with the line signal, when loading with the line signal by time division multiplexing mode, reserve predetermined slot time during time slot allocation, load(ing) point does not load with the line signal in slot time;
With the line detecting signal unit, be used for detecting that the optical service signal that receives loads with the line signal; And
Control unit is switched in protection, be used for the described optical service signal that receives load with the testing result of line signal as the switching optical service signal protection trigger condition, trigger switching optical service signal protection.
Another purpose of the embodiment of the invention is to provide a kind of optical communication system, comprises at least one service source node, and at least one professional destination node, and described service source node comprises:
With line signal loading unit, being used for will be with the line signal loading to optical service signal, describedly be loaded in the optical service signal by frequency division multiplexing, time division multiplexing, code division multiplexing or its combination in any mode with the line signal, when loading with the line signal by time division multiplexing mode, reserve predetermined slot time during time slot allocation, load(ing) point does not load with the line signal in slot time;
Described professional destination node comprises:
With the line detecting signal unit, be used for detecting that the optical service signal that receives loads with the line signal; And
Control unit is switched in protection, be used for the described optical service signal that receives load with the testing result of line signal as the switching optical service signal protection trigger condition, trigger switching optical service signal protection.
Another purpose of the embodiment of the invention is to provide a kind of switching optical service signal protection method, and described method comprises the steps:
Switch the service source node in protection, will be to optical service signal with the line signal loading, described have the protection Overhead with the line signaling bearer, describedly be loaded in the optical service signal by frequency division multiplexing, time division multiplexing, code division multiplexing or its combination in any mode with the line signal, when loading with the line signal by time division multiplexing mode, reserve predetermined slot time during time slot allocation, load(ing) point does not load with the line signal in slot time;
Switch the downstream traffic node in protection, detect load in the optical service signal with the line signal, extract described protection Overhead with the line signaling bearer;
Protection Overhead according to described extraction is carried out corresponding switching optical service signal protection.
Another purpose of the embodiment of the invention is to provide a kind of optical communication equipment, and described equipment comprises:
With line signal loading unit, being used for will be with the line signal loading to optical service signal, described have the protection Overhead with the line signaling bearer, describedly be loaded in the optical service signal by frequency division multiplexing, time division multiplexing, code division multiplexing or its combination in any mode with the line signal, when loading with the line signal by time division multiplexing mode, reserve predetermined slot time during time slot allocation, load(ing) point does not load with the line signal in slot time;
With the line detecting signal unit, be used for detecting that the optical service signal that receives loads with the line signal, extract described protection Overhead with the line signaling bearer; And
Control unit is switched in protection, is used for carrying out corresponding switching optical service signal protection according to what load from the described optical service signal that receives with the protection Overhead that extracts the line signal.
Another purpose of the embodiment of the invention is to provide a kind of optical communication system, comprises at least one service source node, and at least one downstream traffic node, and described service source node comprises:
With line signal loading unit, being used for will be with the line signal loading to optical service signal, described have the protection Overhead with the line signaling bearer, describedly be loaded in the optical service signal by frequency division multiplexing, time division multiplexing, code division multiplexing or its combination in any mode with the line signal, when loading with the line signal by time division multiplexing mode, reserve predetermined slot time during time slot allocation, load(ing) point does not load with the line signal in slot time;
Described downstream traffic node comprises:
With the line detecting signal unit, be used for detecting that the optical service signal that receives loads with the line signal, extract described protection Overhead with the line signaling bearer; And
Control unit is switched in protection, is used for carrying out corresponding switching optical service signal protection according to what load from the described optical service signal that receives with the protection Overhead that extracts the line signal.
The embodiment of the invention is based on carrying out switching optical service signal protection with the line signal detecting result or with the protection Overhead of line signaling bearer; improve the fault detect rate of photosphere and switched success rate; and the availability of system; can also detect and professional the connection whether produce wrong connection; can suppress wrong coproduction and give birth to, improve the efficient that protection is switched.
Description of drawings
Fig. 1 is the shared principle schematic of 1+1 optical channel that prior art provides;
Fig. 2 is that the schematic diagram of control is switched in the shared receiver side protection of 1+1 optical channel that prior art provides;
Fig. 3 be the embodiment of the invention provide to trigger the realization schematic diagram of switching optical service signal protection with the line signal detecting result;
Fig. 4 is that the schematic diagram of control is switched in the shared receiver side protection of 1+1 optical channel that the embodiment of the invention provides;
Fig. 5 is the schematic diagram that light-channel shared protection that the embodiment of the invention provides is switched;
Fig. 6 be the embodiment of the invention provide to carry out the realization schematic diagram of switching optical service signal protection with the Overhead of line signaling bearer.
Embodiment
In order to make purpose of the present invention, technical scheme and advantage clearer,, the present invention is further elaborated below in conjunction with drawings and Examples.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
In embodiments of the present invention; at the service source node; will be to optical service signal with the line signal loading; at professional destination node; to detecting of loading in the optical service signal with the line signal; according to testing result judge whether optical service signal exists, optical service signal OSNR etc., and, trigger the protection of optical service signal and switch the trigger condition of testing result as switching optical service signal protection.Simultaneously, can also switch according to the protection of the protection Overhead execution optical service signal that is carried with the line signal.
In embodiments of the present invention, at the service source node that protection is switched, will be in optical service signal with the line signal loading.The service source node can be for carrying out the node of bridge joint request; include but not limited to service source node or fault service source node; at different protection levels; it can be service source; also may be the source of trouble, for example other protection of optical channel level be wavelength service source node down; transmit Duan Eryan for optical multiplexing section or light, be fault service source node.Switch professional destination node in protection, detect load in the optical service signal with the line signal, with the trigger condition of testing result as switching optical service signal protection.Professional destination node includes but not limited to the professional destination node of professional destination node or fault for initiating the node of protection switching request.At different protection levels, it can be professional destination node that professional destination node is switched in protection, also may be the professional destination node of fault; for example other protection of optical channel level down; for the professional destination node of wavelength, transmit Duan Eryan for optical multiplexing section or light, be the professional destination node of fault.
Can comprise the id information of load(ing) point with the line signal, need the Overhead that transmits, a string fixing or at random or one of them or its combination of the bit of appointment or byte.
Loading with the line signal can have multiple mode, in one embodiment of this invention, also can adopt the mode of frequency division multiplexing to load with the line signal, different adopt different frequencies or Frequency point to make up to represent with the line signal a plurality of with the line signal, the mixing of finishing a plurality of channel association tag signals by frequency division multiplexing and demultiplexing with separate.
In another embodiment of the present invention, can load with the line signal by time-multiplexed mode, for load(ing) point distributes different time slots, each load(ing) point distributes time slot to send the optical service signal that has loaded with the line signal at it.Different load(ing) points sent with life period between the line signal at interval, to avoid with the line signal conflict.Because also there is certain time-delay each other in load(ing) point, therefore when time slot allocation, can be reserved with certain slot time, load(ing) point does not load with the line signal in slot time, allow each load(ing) point to have the regular hour surplus to load like this with the line signal, avoid time slot adjacent sign to overlap, bring out conflict, thereby can reduce synchronous requirement, reduce and realize cost load(ing) point.By being the different time slots of different load(ing) points distribution, controlling different load(ing) points loads with the line signal at different time, by time slot allocation or token mechanism, what guarantee that different load(ing) point loads can not occur at one time with the line signal, thereby has realized the time division multiplexing of channel association tag signal.
In one embodiment of the invention, also can adopt the mode of code division multiplexing to load with the line signal, each load(ing) point distributes unique discernible spreading code respectively, load(ing) point by its unique discernible spreading code to carrying out spread processing with the line signal.Spreading code can be unipolar spreading codes such as prime number sign indicating number, light orthogonal code, quadratic congruence codes, expansion prime number sign indicating number, expansion quadratic congruence codes, hybrid code or improvement prime number sign indicating number of quadrature.
Because code division multiple access (Code Division Multiple Access, CDMA) can bring extra coding gain, therefore, for taking the CDMA method to carry out spread processing with the line signal, can bring extra coding gain with the line signal behind the spread spectrum, allow higher detection sensitivity, and in same detection range, can further reduce modulation depth, thereby reduce annoyance level the main optical business signal with the line signal.
Certainly, also can take the loading of the combination in any realization of above-mentioned load mode as required with the line signal.
When optical service signal is modulated, can utilize electricity to regulate optical attenuator (Electrically-controlledVariable Optical Attenuator, EVOA) optical service signal is inserted its input port, utilization is with its loss of line signal controlling, to be reflected to the power of line signal in the light intensity variation of optical service signal, realize with of the modulation of line signal to optical service signal.Also can pass through semiconductor optical amplifier (Semiconductor Optical.Amplifier, SOA) optical service signal is inserted its input port, utilization is with its gain of line signal controlling, will be added on the optical service signal with the line signal, finishes the loading with the line signal.
For fear of optical service signal being produced excessive interference with the line signal, generally to be arranged between 3～5% controlling with the modulation depth of line signal, maximum is no more than 10%.Simultaneously, also need to control power with the line signal, because the bandwidth of optical service signal is generally in the G level, with the bandwidth range of line signal generally below 100MHz, but also can be in the 100MHz rank, excessive for fear of disturbing, the bandwidth of optical service signal and with 1 difference more than the order of magnitude is preferably arranged between the bandwidth of line signal, so the cycle of optical service signal is greater than or equal to ten times with the line signal period.
When detecting with the line signal, optical service signal after test point is to modulation carries out beam split, and the optical service signal after the beam split is converted to the signal of telecommunication, then the signal of telecommunication is carried out filtering, and the filtered signal of telecommunication is carried out despreading with corresponding spreading code, from the signal of telecommunication, isolate corresponding with the line signal.After the line Signal Separation, test point is to detecting with the line signal.In embodiments of the present invention, testing result with the line signal comprises the performance number with the line signal, the power detection result or the OSNR testing result of optical service signal, also may further include performance number and the comparative result that presets thresholding with the line signal.
When test point carries out despreading to the channel association tag signal, when having only single channel association tag signal, adopt the spreading code of load(ing) point correspondence that the channel association tag signal is carried out despreading, obtain this load(ing) point with the line signal.If mixed behind a plurality of load(ing) point spread spectrums with the line signal time, then earlier the filtered signal of telecommunication is carried out shunt, with the despreading that walks abreast of the signal of telecommunication of the pairing spreading code of each load(ing) point after to shunt, it is pairing with the line signal to obtain each load(ing) point respectively.
Detection method to the signal after the despreading can be divided into following four kinds:
One, detects in the signal after the despreading with the power component of line signal, judge corresponding whether existing with the line signal;
Two, detect in the signal after the despreading power component, and its and decision threshold are compared, judge whether existing of correspondence with the line signal with the line signal;
Three, detect in the signal after the despreading expense,, judge corresponding whether exist with the line signal etc. according to expense with the line signal;
Four, detect in the signal after the despreading with the power component of line signal, calculate the power component and the OSNR of corresponding optical service signal.The DC component gross power of the signal of telecommunication after supposing to change is Ptotal, by detection with the power component of line signal, in conjunction with known modulation depth, calculate each and be respectively Ps1, Ps2...Pn with the pairing power component of line signal, suppose in the optical service signal because the introducing of the image intensifer in circuit spontaneous emission noise (ASE) power is Pase, then Ptotal=Ps1+Ps2+...Pn+Pase calculates the ASE component, and then calculates the OSNR of optical service signal.
In embodiments of the present invention; utilization is with the testing result of the line signal testing conditions as switching optical service signal protection; have only with professional corresponding satisfy with the line quality of signals protect when switching trigger condition; optical switch just can be carried out corresponding protection switching action, detects the defective that is difficult to reflect strictly according to the facts the optical service signal situation thereby can fully evade simple luminous power.
Fig. 3 show that the embodiment of the invention provides to trigger the realization principle of switching optical service signal protection with the line signal detecting result, for convenience of explanation, only show the part relevant with the embodiment of the invention.
Switch the service source node in protection, be provided with line signal loading unit, will be to the optical service signal of service aisle and backup path with the line signal loading.Switch professional destination node in protection; be provided with line detecting signal unit and protection and switch control unit; with the line detecting signal unit to detecting of loading in the optical service signal with the line signal; protection switch control unit with the line detecting signal unit with the line signal detecting result as the switching optical service signal protection trigger condition, trigger switching optical service signal protection.
When specific implementation, support the optical node of switching optical service signal protection to be provided with line signal loading unit usually, to switch control unit for one with line detecting signal unit and protection.Wherein, in the optical service signal that will send with line signal loading to optical node with line signal loading unit; load in the optical service signal that optical node is received with the line detecting signal unit with the line signal; protection switch control unit with the line detecting signal unit with the line signal detecting result as the switching optical service signal protection trigger condition, trigger switching optical service signal protection.
Protection changeover apparatus with 1+1 Optical Channel Protection receiver side is an example; as shown in Figure 4; all be provided with coupler and power-sensing circuit PIN1 at service aisle and backup path; PIN2; coupler is used for a part of optical service signal is got off to be used for to detect along separate routes; PIN1; PIN2 finishes the conversion of optical service signal to the signal of telecommunication; finish Detection and Extraction with the line detecting signal unit with the line signal; be sent to protection at last with the line signal detecting result and switch control unit; switch the comparison of finishing service signal in the control unit in protection; protection is switched control unit and is finished corresponding protection switching action according to comparative result control optical switch, selects service aisle or backup path to transmit passage as business.
In order to further describe the concrete implementation of the embodiment of the invention, below be the protection reversed process of example Mingguang City service signal with the light-channel shared protection.
Light-channel shared protection; can be described as having connected shared with a pair of wavelength X 1 and λ 2 in the two-way services that on different sections, exist on the ring; λ 1 and λ 2 are respectively on two different optical fiber; meanwhile, the protection wavelength that the wavelength X 2 of correspondence and λ 1 are used as operation wavelength λ 1 and λ 2 on these two optical fiber.Since different two-way services connect all be shared with a pair of wavelength as the protection wavelength, therefore this protected mode is known as light-channel shared protection (OCh-SPRing).
For the node that participates in light-channel shared protection, it must the supporting business break-through, on business and following three functions of business.Professional break-through is meant that the protection business of other website can be in the direct break-through of this website, to guarantee correctly to be sent to its destination node.Refer on the business after local business is affected, can correctly be switched on the backup path and transmits.Professional next finger destination for local business after service aisle is subjected to fault effects, can be sent to this locality by backup path, and can the business of backup path correctly be incorporated into receiver in this locality.After service aisle breaks down; initiate the protection switching request by professional destination node, the service source node switches the business to backup path, and intermediate node is selected professional break-through; at professional destination node business is switched again, switch whole process thereby finish service protection.
In order to realize that on node above-mentioned three kinds of functions, common light channel sharing protection method all are by optical demultiplexer, optical multiplexer a pair of wavelength separated to be come out earlier, handle this a pair of wavelength afterwards in the light-channel shared protection changeover apparatus.
Fig. 5 shows the inside of existing light-channel shared protection node and forms schematic diagram, and wherein letter w is represented work (Work) wavelength, and alphabetical P represents protection (Protect) wavelength, and operation wavelength and protection wavelength adopt solid line and dotted line to represent respectively.Letter D represents road business (Drop) down, and alphabetical A represents the business of setting out on a journey (Add), and direct-connected (Express) expression is professional without the direct break-through of light-channel shared protection device.
At light-channel shared protection intranodal shown in Figure 5; the west to outer fine wavelength W11 adopt wavelength X 1 as operation wavelength; the west to interior fine wavelength W21 adopt wavelength X 2 as operation wavelength; the outer fine wavelength W12 of east orientation adopts wavelength X 1 as operation wavelength, and the interior fine wavelength W22 of east orientation adopts wavelength X 2 as operation wavelength.Meanwhile; the west to outer fine wavelength P22 adopt the protection wavelength of wavelength X 2 as W22; the west to interior fine wavelength P12 adopt the protection wavelength of wavelength X 1 as W12; the outer fine wavelength P21 of east orientation adopts the protection wavelength of wavelength X 2 as W21, and the interior fine wavelength P11 of east orientation adopts the protection wavelength of wavelength X 1 as W11.Like this, on the two-way services of two sections optical fiber that this node connects, realized light-channel shared protection with regard to shared a pair of wavelength.
At intranodal; after this wavelength being come out to demultiplexing from two line directions of thing earlier by optical add/drop multiplexer; after the processing of light-channel shared protection changeover apparatus; after optical add/drop multiplexer is multiplexing, send again from two line directions of thing; the road business is also finished the professional He Xialu that sets out on a journey by the light-channel shared protection changeover apparatus up and down; node wherein shown in Figure 5 is finished the following road of setting out on a journey of the outer fine professional A2 of going up and professional D1, and the setting out on a journey and the following road of professional D2 of professional A1 on the interior fibre.When ring was gone up certain section optical fiber or node and broken down, receiving end detected a certain direction signal and loses the back and automatically switch the signal of selective reception other direction.For example; when node shown in Figure 5 west to outer fibre when breaking down, the light-channel shared protection device detects from the west to the outer optical fiber signaling W11 that receives to be lost, and then automatically switches to the fine signal P11 that receives in the east orientation; P11 realizes service protection as the protection wavelength of W11.
In Fig. 5, two transmitting terminals of first optical add/drop multiplexer are connected with P22 with W11 respectively, two receiving terminals of second optical add/drop multiplexer are connected with P21 with W12 respectively, two receiving terminals of the 3rd optical add/drop multiplexer are connected with P12 with W21 respectively, and two transmitting terminals of the 4th optical add/drop multiplexer are connected with P11 with W22 respectively.Four, first optical add/drop multiplexer goes out the service signal of service aisle and the service signal of backup path with the wavelength that the thing both direction comes to demultiplexing respectively, and is transferred to the light-channel shared protection device.The service aisle that the wavelength that second, third optical add/drop multiplexer removes the thing both direction respectively is right and the service signal of backup path are multiplexed with one road signal and send out.There is not the wavelength of professional contact for this locality, by first and second, direct-connected passage Express carries out punch-through process between the 3rd and the 4th optical add/drop multiplexer.
In the embodiment of the invention, embedded with line signal loading unit on the defeated light-emitting window W12 of light-channel shared protection device, W21, P12, P21, corresponding on optical service signal, to increase with the line signal with the wavelength service signal.Under the general situation, should be corresponding one by one with the wavelength business with the line signal.Certainly, increasing embedded on set out on a journey inlet A1, A2 also is feasible with line signal loading unit, can substitute this moment on W12, W21, P12, the P21 with line signal record function.
Simultaneously, on two service aisles defeated light inlet W11, W22, be provided with the line detecting signal unit, whether break down with line signal judgment task passage by detecting, and whether initiate to switch with the testing result decision of line signal according to service aisle.Whether also can be provided with the line detecting signal unit on two backup path defeated light inlet P11, P22 simultaneously, it is normal to detect backup path.
After fault takes place; can detect with the line dropout on defeated light inlet W11 of service aisle or the W22 with the line detecting signal unit; this node according on W11, the W22 with the line dropout; can judge the west to or the east orientation service aisle take place unusual, thereby start light-channel shared protection.If detecting with the line dropout on back-up job passage defeated light inlet P11, the P22 with the line detecting signal unit, it is unusual to mean that backup path produces, for the wavelength business that business has been switched on the backup path, then can once more business be switched back service aisle.Just often also can do the monitoring of backup path state at network with the line detecting signal unit on back-up job passage defeated light inlet P11, the P22; but in most of the cases; backup path under the light-channel shared protection does not have optical service signal to transmit, and therefore can lose efficacy with the line input.
The embodiment of the invention not only can be used for other Optical Channel Protection of wavelength level; for example 1+1 Optical Channel Protection, light-channel shared protection, 1:1 Optical Channel Protection, 1:N Optical Channel Protection etc.; the optical multiplexing section protection that can also be used for the multiplex section level, for example 1+1 optical multiplexing section protection.When optical multiplexing section protection; can on each wavelength, load with the line signal; whether each control point judges with the existence of line signal whether the multiplex section signal breaks down by detecting wavelength; as long as existing or normal with the line signal of a wavelength arranged; can think that the optical multiplexing section signal is normal; have only all wavelengths with the line dropout, just be considered as recovery and use abnormal signal, and startup is responsible to replace and is switched.Optical multiplexing section protection can start by the mode of detection optical multiplexing section with the line signal simultaneously; promptly on optical multiplexing section, directly load with the line signal; and switch test point in protection this optical multiplexing section is detected with the line signal; if optical multiplexing section, can trigger optical multiplexing section with the line abnormal signal and switch.The protection reverse triggering process of optical transmission section is consistent with the optical multiplexing section protection reverse triggering process, does not repeat them here.
In embodiments of the present invention, not only can come trigger protection to switch with the line signal, also utilize simultaneously, need the mutual protection scheme of both-end that the transmission of protection signaling is provided light-channel shared protection etc. with line signal transmission protection Overhead by detecting.The protection Overhead comprises the node identification (for example ID number) that is used to specify destination node, the node identification (for example ID number) of start node, professional numbering, action indication etc.; node ID number is used for each node and judges whether current network is normal; professional numbering is used for node and judges which business is handled; the action indication is used for the action that instructs node need be taked, or even switches confirmation to peer node transmission protection.
More particularly, exactly protection switch the service source node load one carried the protection Overhead with the line signal, should be modulated on wavelength signals or the wavelength signals group with the line signal.At different protection levels, it can be service source that the service source node is switched in protection, also may be the source of trouble, and for example other protection of optical channel level is wavelength service source node down, transmits Duan Eryan for optical multiplexing section or light, is fault service source node.
Switch detecting that the service source node sent at the downstream traffic node that protection is switched on the backup path to being responsible to replace, and therefrom extract the protection Overhead, carry out corresponding protection action according to the protection Overhead with the line signal.The downstream traffic node comprises that intermediate node and protection switch professional destination node; at different protection levels; it can be professional destination node that professional destination node is switched in protection; it also may be the professional destination node of fault; for example other protection of optical channel level down; for the professional destination node of wavelength, transmit Duan Eryan for optical multiplexing section or light, be the professional destination node of fault.
Whether equally also transmit similarly protection Overhead on the operating path, be used to indicate the processing of finishing the backup path transport service, it is normal also can be used for the testing passage simultaneously.Under normal circumstances, the protection expense Detection and Extraction on the service aisle must be normal, when appearance protection Overhead extracts failure, just may be that service aisle is unusual, therefore protect Overhead extraction failure also to can be used as the trigger condition that protection is switched.
Fig. 6 show that the embodiment of the invention provides to carry out the realization principle of switching optical service signal protection with the Overhead of line signaling bearer, for convenience of explanation, only show the part relevant with the embodiment of the invention.
Switch the service source node in protection; be provided with line signal loading unit; will be to optical service signal with the line signal loading; with carrying the protection Overhead in the line signal, comprise the node identification with the node identification of specifying destination node, start node, professional numbering, action indication etc.At the downstream traffic node; be provided with line detecting signal unit and protection and switch control unit; with the line detecting signal unit detect load in the optical service signal with the line signal; extraction is with the protection Overhead that carries in the line signal, and protection is switched control unit and carried out corresponding switching optical service signal protection according to the protection Overhead that extracts with the line detecting signal unit.
When specific implementation, support the optical node of switching optical service signal protection to be provided with line signal loading unit usually, to switch control unit for one with line detecting signal unit and protection.Wherein, to carry with line signal loading unit in the optical service signal that sends with line signal loading to optical node of protection Overhead; load in the optical service signal that optical node is received with the line detecting signal unit with the line signal; extract the protection Overhead of its carrying, protection is switched control unit and is carried out corresponding switching optical service signal protection according to the protection Overhead that extracts with the line detecting signal unit.
Obviously, the embodiment of the invention is not only applicable to the trigger condition as switching optical service signal protection, can be used as the testing conditions that optical service signal recovers simultaneously, and specific implementation repeats no more.
The embodiment of the invention is at existing detection based on optical service signal power; to situation that situation can't detect such as Optical Signal To Noise Ratio deterioration, part wavelength be impaired; provide based on the line signal detecting result or with the protection reverse method of the protection Overhead of line signaling bearer; improve the fault detect rate of optical service signal layer greatly and switched success rate, improved the availability of system.Simultaneously, the embodiment of the invention can detect professional the connection whether to produce wrong connection, can suppress wrong coproduction and give birth to.Can integrate with line detecting signal unit and performance element in the embodiment of the invention avoided communicating by letter between complicated functional unit, improved protection and switched efficient.
The above only is preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of being done within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.
Claims (18)
1. a switching optical service signal protection method is characterized in that, described method comprises the steps:
Switch the service source node in protection, will be to optical service signal with the line signal loading, describedly be loaded in the optical service signal by frequency division multiplexing, time division multiplexing, code division multiplexing or its combination in any mode with the line signal, when loading with the line signal by time division multiplexing mode, reserve predetermined slot time during time slot allocation, load(ing) point does not load with the line signal in slot time;
Switch professional destination node in protection, to detecting of loading in the optical service signal with the line signal;
With with the line signal detecting result as the switching optical service signal protection trigger condition, trigger switching optical service signal protection.
2. switching optical service signal protection method as claimed in claim 1; it is characterized in that, described with the line signal detecting result comprise performance number with the line signal, the power detection result of the optical service signal that obtains according to performance number or the Optical Signal To Noise Ratio testing result of optical service signal with the line signal.
3. switching optical service signal protection method as claimed in claim 2 is characterized in that, describedly comprises with the performance number of line signal and the comparative result of default thresholding with the line signal detecting result.
4. switching optical service signal protection method as claimed in claim 1 is characterized in that, described protection is switched the service source node for carrying out the node of bridge joint request, comprises service source node or fault service source node.
5. switching optical service signal protection method as claimed in claim 1 is characterized in that, described protection is switched professional destination node for initiating the node of protection switching request, comprises the professional destination node of professional destination node or fault.
6. switching optical service signal protection method as claimed in claim 1 is characterized in that, described switching optical service signal protection comprises that Optical Channel Protection is switched, optical multiplexing section protection is switched or the optical transmission section protection is switched.
7. switching optical service signal protection method as claimed in claim 6 is characterized in that, described Optical Channel Protection is switched and comprised 1:1 Optical Channel Protection, 1+1 Optical Channel Protection, light-channel shared protection or 1:N Optical Channel Protection.
8. an optical communication equipment is characterized in that, described equipment comprises:
With line signal loading unit, being used for will be with the line signal loading to optical service signal, describedly be loaded in the optical service signal by frequency division multiplexing, time division multiplexing, code division multiplexing or its combination in any mode with the line signal, when loading with the line signal by time division multiplexing mode, reserve predetermined slot time during time slot allocation, load(ing) point does not load with the line signal in slot time;
With the line detecting signal unit, be used for detecting that the optical service signal that receives loads with the line signal; And
Control unit is switched in protection, be used for the described optical service signal that receives load with the testing result of line signal as the switching optical service signal protection trigger condition, trigger switching optical service signal protection.
9. optical communication equipment as claimed in claim 8, it is characterized in that, described with the line signal detecting result comprise performance number with the line signal, the power detection result of the optical service signal that obtains according to performance number or the Optical Signal To Noise Ratio testing result of optical service signal with the line signal.
10. optical communication equipment as claimed in claim 8 is characterized in that, described switching optical service signal protection comprises that Optical Channel Protection is switched, optical multiplexing section protection is switched or the optical transmission section protection is switched.
11. an optical communication system comprises at least one service source node, and at least one professional destination node, it is characterized in that, described service source node comprises:
With line signal loading unit, being used for will be with the line signal loading to optical service signal, describedly be loaded in the optical service signal by frequency division multiplexing, time division multiplexing, code division multiplexing or its combination in any mode with the line signal, when loading with the line signal by time division multiplexing mode, reserve predetermined slot time during time slot allocation, load(ing) point does not load with the line signal in slot time;
Described professional destination node comprises:
With the line detecting signal unit, be used for detecting that the optical service signal that receives loads with the line signal; And
Control unit is switched in protection, be used for the described optical service signal that receives load with the testing result of line signal as the switching optical service signal protection trigger condition, trigger switching optical service signal protection.
12. a switching optical service signal protection method is characterized in that described method comprises the steps:
Switch the service source node in protection, will be to optical service signal with the line signal loading, described have the protection Overhead with the line signaling bearer, describedly be loaded in the optical service signal by frequency division multiplexing, time division multiplexing, code division multiplexing or its combination in any mode with the line signal, when loading with the line signal by time division multiplexing mode, reserve predetermined slot time during time slot allocation, load(ing) point does not load with the line signal in slot time;
Switch the downstream traffic node in protection, detect load in the optical service signal with the line signal, extract described protection Overhead with the line signaling bearer;
Protection Overhead according to described extraction is carried out corresponding switching optical service signal protection.
13. switching optical service signal protection method as claimed in claim 12 is characterized in that, described protection Overhead comprises the node identification that is used to specify destination node, the perhaps node identification of start node, and perhaps professional numbering is perhaps moved indication information.
14. switching optical service signal protection method as claimed in claim 12 is characterized in that, described service source node comprises service source node or fault service source node for carrying out the node of bridge joint request.
15. switching optical service signal protection method as claimed in claim 12; it is characterized in that; described downstream traffic node comprises that intermediate node or protection switch professional destination node; described protection is switched professional destination node for initiating the node of protection switching request, comprises the professional destination node of professional destination node or fault.
16. an optical communication equipment is characterized in that, described equipment comprises:
With line signal loading unit, being used for will be with the line signal loading to optical service signal, described have the protection Overhead with the line signaling bearer, describedly be loaded in the optical service signal by frequency division multiplexing, time division multiplexing, code division multiplexing or its combination in any mode with the line signal, when loading with the line signal by time division multiplexing mode, reserve predetermined slot time during time slot allocation, load(ing) point does not load with the line signal in slot time;
With the line detecting signal unit, be used for detecting that the optical service signal that receives loads with the line signal, extract described protection Overhead with the line signaling bearer; And
Control unit is switched in protection, is used for carrying out corresponding switching optical service signal protection according to what load from the described optical service signal that receives with the protection Overhead that extracts the line signal.
17. optical communication equipment as claimed in claim 16 is characterized in that, described protection Overhead comprises the node identification that is used to specify destination node, the perhaps node identification of start node, and perhaps professional numbering is perhaps moved indication information.
18. an optical communication system comprises at least one service source node, and at least one downstream traffic node, it is characterized in that, described service source node comprises:
With line signal loading unit, being used for will be with the line signal loading to optical service signal, described have the protection Overhead with the line signaling bearer, describedly be loaded in the optical service signal by frequency division multiplexing, time division multiplexing, code division multiplexing or its combination in any mode with the line signal, when loading with the line signal by time division multiplexing mode, reserve predetermined slot time during time slot allocation, load(ing) point does not load with the line signal in slot time;
Described downstream traffic node comprises:
With the line detecting signal unit, be used for detecting that the optical service signal that receives loads with the line signal, extract described protection Overhead with the line signaling bearer; And
Control unit is switched in protection, is used for carrying out corresponding switching optical service signal protection according to what load from the described optical service signal that receives with the protection Overhead that extracts the line signal.
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