CN1703008A - Passive optical network protecting method and system - Google Patents

Abstract

This invention relates to light with no source protection method and system and relates to light communication technique. The invention aims to solve the problem of the current inefficient protection and realize the protection of the PON system. The invention sets back OLT connected to the back OLT through light switch.

Description

Passive optical network protecting method and system

Technical field

The present invention relates to optical communication technology, the resist technology of particularly a kind of EPON (PON).

Background technology

Recently, along with the high speed development of Internet, the user constantly improves the demand of the network bandwidth, and traditional Access Network has become the bottleneck in the whole network, and replacing with new broadband access technology becomes the inexorable trend of development.(Passive OpticalNetwork, PON) technology more and more is subject to people's attention as a kind of Optical Fiber Transmission and access technology of point-to-multipoint EPON.As " last kilometer " final solution, progressively accepted by vast operator, obtain large-scale application at present in the world.This system can be divided into APON and EPON according to the difference of transmission mechanism.They adopt descending employing broadcast mode, up employing time division multiple access way or ethernet technology, adopt passive device.Do not need node device at optical branch point, only need to install a simple optical branching device and get final product, therefore have the cable resource of saving, bandwidth resources share, save machine room investment, device security height, networking speed soon, comprehensive networking low cost and other advantages.

A typical PON system is made up of N work OLT (optical line terminal), ODN (Optical Distribution Network), ONU (optical network unit) and EMS (Element management system) respectively as shown in Figure 1.Network configuration can be tree type, bus-type, star-like and annular etc.Wherein OLT is positioned on the frame of Central Exchange, it both can be a switch or router, be again that a multi-service provides platform, interface between EPON system and service provider's core data, video and the telephone network is provided, being connected of distribution and control channel, and real-time monitoring, management and maintenance function are arranged.It is linked on service provider's the core network by an EMS.ONU is positioned at user side, is placed on a resident family, enterprise, place, commercial building.ODN mainly contains various Passive Optical Components such as optical fiber, the 1:n channel-splitting filter is formed.EMS manages each component units among the PON, and provides the standard network management interface to service provider's core net.Its management responsibility comprises all management functions such as fault, configuration, charging, performance and safety.Main feature and the function of EMS comprise: by a graphical user interface (GUI), can manage tens PON systems of equipment fully; The network management interface of standard is provided to core net.

The transmission plan of EPON is with 1310nm wavelength transmission narrow band service signal, with 1550nm wavelength transmission width service signal.Adopt Multi-point Control Protocol (MPCP, Multi-Point Control Protocol), time division multiplexing (TDMA) and ranging technology simultaneously.

Reduce installation, management and operation cost because PON has, improve rate of return on investment, increase new profit chance, the characteristics of retaining its competitive edge for a long time or the like are subjected to the welcome of operator deeply.A lot of operators adopt PON as access way, miscellaneous services such as data, voice, video are provided for the user, and obtain income.We understand by figure one, and OLT is as the core of system, if problem, whole PON system will paralyse.All business all can't be carried out, and professional must the operation caused bad consequence, and operator also can't obtain income.Therefore when making up the PON system, take into full account protection, can improve the stability of whole system like this OLT.And set up a good stability, reliability height, the PON system being convenient to safeguard is the prerequisite that operator obtains income.

Simultaneously, the fast development along with APS technology (APS, Automatic ProtectionSwitching) has all obtained good extensive use in SDH, metropolitan area network and Ethernet.The APS technology is used for PON, all can a very big raising for the survivability and the robustness of PON network.

Summary of the invention

Technical problem to be solved by this invention is, at the problem that existing P ON may exist, proposes a kind of resist technology that OLT was lost efficacy, and is implemented in the PON system OLT and loses efficacy the carrier-class protection is provided.Can also go up professional priority according to OLT at when a plurality of OLT break down simultaneously, at first the preferential OLT of height be protected.

The technical scheme that the present invention solve the technical problem employing is:

Passive optical network protecting method is provided with spare OLT, and each OLT that works is by optical switch and spare OLT and connect, and when a certain work OLT lost efficacy, takes over the work OLT of inefficacy with spare OLT.

Inefficacy work OLT surpass one the time, according to the passage priority orders, take over the inefficacy work OLT of the higher relatively passage of priority with spare OLT.Further, may further comprise the steps:

1) the APS module detects the operating state of each OLT;

2) inefficacy OLT service aisle is carried out priority ratio, the OLT that works in high-priority channel is protected switching, take over the work OLT of inefficacy with spare OLT.

Also comprise step 3): normal if inefficacy OLT recovers, then switch back former OLT, described " former OLT " is meant the OLT that was taken over by spare OLT owing to lost efficacy.

Described step 3) also can be: if after protection is switched, new OLT occurs and lost efficacy, then new OLT service aisle priority and spare OLT service aisle are compared, if new OLT service aisle priority is higher, then spare OLT is switched to this passage.

The present invention also provides a kind of EPON protection system, comprising:

OLT (1), OLT (2) ... ..OLT (N), and spare OLT, spare OLT is in parallel with other OLT by optical switch;

And, the ASP module, described ASP module is connected with each OLT, detects the state of each OLT, and when a certain OLT lost efficacy, ASP controlled optical switch, takes over inefficacy OLT with spare OLT.

If a plurality of OLT lost efficacy, ASP is its service aisle priority relatively, controls optical switch, takes over the inefficacy OLT of the higher passage of priority with spare OLT.

The invention has the beneficial effects as follows that when optical line terminal (OLT) when breaking down, this system can provide the carrier-class APS in a short period of time, guarantee professional continuity, improved the survivability of optical network system.New like this protection system that the present invention proposes and guard method can realize that for the assurance system carrier-class operation played significant effect, when genuine especially a plurality of inefficacies take place simultaneously, the priority protection method has very high practical value.The present invention also can be used in the situation of other inefficacies for the method that switches to protection OLT that OLT lost efficacy and adopts.

The present invention is further illustrated below in conjunction with the drawings and specific embodiments.

Description of drawings

Fig. 1 is a background technology schematic diagram of the present invention.

Fig. 2 is first kind of execution mode schematic diagram of the present invention.

Fig. 3 is the schematic diagram of the system of first kind of execution mode of the present invention when normally moving.

Fig. 4 is the system of first kind of execution mode of the present invention when breaking down, the schematic diagram of protection mechanism operation.

Fig. 5 is a workflow diagram of the present invention.

Embodiment

Referring to Fig. 2-4, PON system of the present invention mainly is made up of the OLT system that has defencive function, working optical fibre, 2xN optical branching device unit.The OLT system that wherein has a defencive function comprises N-1 work OLT unit, protection OLT unit and APS module, 1xN optical switch and n-1 1x2 optical switch composition.The APS module is responsible for input and the judgement that the OLT module lost efficacy, and carries out switching and recovering of optical switch.The APS module connects N-1 work OLT and a protection OLT, also connects with the 1xN optical switch simultaneously. and protection OLT links to each other with 1 input of 1xN optical switch.The delivery outlet of N-1 port in the N of the 1xN optical switch output and N-1 work OLT is connected respectively to two input ports of 1x2 optical switch, and the delivery outlet of 1x2 optical switch links to each other with the optical fiber of ODN.The previously described spare OLT of OLT among the figure (protection) the present invention just.

In fact, the object of protection of protection system of the present invention is the passage of signal, and this " passage " is not the circuit on the physical significance, but the logic of a certain road signal of communication.Such passage needs the physical circuit support, if a certain section physical circuit breaks down, by protection mechanism of the present invention, enables extension wire, though physical circuit changes, " passage " of signal is constant.

During the system operate as normal, ONU is optical fiber, trunk optical fiber and the 1x2 optical switch arrival work OLT unit by limb just.Externally carry out exchanges data by work OLT again.All work OLT (OLT1; OLT2 ... OLT n-1) can both work normally; the OLT (protection) of this moment is in idle condition; the APS module is responsible for all OLT signal operating states are detected; and the state of control 1x2 optical switch and 1xN optical switch; make each work OLT to link to each other with trunk optical fiber by the 1x2 optical switch, OLT (protection) transmits a signal to N port of optical switch, thereby makes whole system normally move.When certain the work OLT in the system breaks down (Fig. 4); when the APS module will detect the alarm of this inefficacy; can send with corresponding 1x2 optical switch the 1xN optical switch and switch order, the ONU that will link to each other with this work OLT switches on the OLT (protection).At this time, ONU just arrives OLT (protection) unit by limb optical fiber, trunk optical fiber and 1x2 optical switch, 1xN optical switch, externally carries out exchanges data by OLT (protection) again.After APS switched generation, OLT (protection) switched to operating state from idle condition, so the business of the responsible ONU that is attached thereto, the APS module can report the EMS alarm simultaneously, and current switch status at once.So just guaranteed that after system switched, system can move normally.

The situation that while lost efficacy simultaneously at a plurality of OLT, the APS module can be judged the priority of OLT before execute protection is switched, for the high OLT of priority, at first protect.

This system also provides the restore funcitons of network.After certain work OLT recovered operate as normal, the APS module can be carried out and recover to switch, and will switch back normal work OLT again in the business in the OLT protection.

Fig. 5 is system works flow process figure of the present invention; Flow process is resolved as follows:

The first step starts, and system starts working.

In second step, the APS module detects the operating state of OLT, also obtains relevant warning information from OLT simultaneously.

In the 3rd step,,, if not, entered for the 4th step if system normally moves by pilot signal judgment task OLT operate as normal whether.

Whether in the 4th step, detecting other work OLT also has alarm, if there are a plurality of alarms simultaneously, carry out the protection of the alarm OLT of high priority earlier and switches; If do not have more senior OLT to lose efficacy, then implement protection at this OLT.

In the 5th step, system works is in the OLT guard mode;

In the 6th step, whether APS module detection system fault disappears.If disappear; Judge whether to also have other alarms to occur, if having then carry out new switching; If just do not recover normal operating conditions.

In the present embodiment, each passage has different priority, and corresponding setting is arranged in protection mechanism: if a plurality of OLT produces fault simultaneously, the passage that priority is high obtains priority protection.If alternate channel is occupied by the passage of low priority, then disconnect the minimum passage of priority, the OLT that its physical circuit that takies is given high-priority service uses.Be that OLT is the passage use of high priority, to guarantee the unimpeded of important service to greatest extent.

Claims (7)

1, passive optical network protecting method is characterized in that, spare OLT is set, and each OLT that works is by optical switch and spare OLT and connect, and when a certain work OLT lost efficacy, takes over the work OLT of inefficacy with spare OLT.

2, passive optical network protecting method as claimed in claim 1 is characterized in that, inefficacy work OLT surpass one the time, according to the passage priority orders, take over the inefficacy work OLT of the higher relatively passage of priority with spare OLT.

3, passive optical network protecting method as claimed in claim 1 or 2 is characterized in that, may further comprise the steps:

1) the APS module detects the operating state of each OLT;

2) inefficacy OLT service aisle is carried out priority ratio, the OLT that works in high-priority channel is protected switching, take over the work OLT of inefficacy with spare OLT.

4, passive optical network protecting method as claimed in claim 3 is characterized in that, also comprises step 3): normal if inefficacy OLT recovers, then switch back former OLT, and described former OLT is meant the OLT that was taken over by spare OLT owing to lost efficacy.

5, passive optical network protecting method as claimed in claim 3; it is characterized in that; also comprise step 3): if after protection is switched; new OLT occurring lost efficacy; then new OLT service aisle priority and spare OLT service aisle are compared; if new OLT service aisle priority is higher, then spare OLT is switched to this passage.

6, EPON protection system comprises:

OLT (1), OLT (2) ... ..OLT (N), and spare OLT, spare OLT is in parallel with other OLT by optical switch;

And, the ASP module, described ASP module is connected with each OLT, detects the state of each OLT, and when a certain OLT lost efficacy, ASP controlled optical switch, takes over inefficacy OLT with spare OLT.

7, EPON protection system as claimed in claim 6 is characterized in that, if a plurality of OLT lost efficacy, ASP is its service aisle priority relatively, controls optical switch, takes over the inefficacy OLT of the higher passage of priority with spare OLT.

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