CN106851439A - A kind of cut-in method and device of multiple optical network units - Google Patents

Abstract

The invention discloses a method for accessing a plurality of optical network units (ONUs), comprising: in the uplink direction, according to the bandwidth allocated by each virtual ONU, acquiring the sending time slot of each virtual ONU, and assembling according to the allocated bandwidth In the downlink direction, when the ONU frame data sent by the OLT is received, and after the delimitation, descrambling and FEC decoding of the downlink frame, the PLOAM message, Bandwidth information, GEM payload data, and OMCI messages; after processing PLOAM messages and OMCI messages, dynamically update MAC information according to OLT configuration; in different processing units, each virtual ONU has its own PLOAM messages, bandwidth information, GEM net Load data and OMCI messages are processed accordingly. The invention also discloses a multiple ONU access device at the same time.

Description

A method and device for accessing multiple optical network units

technical field

The present invention relates to the field of passive optical network (PON, Passive Optical Network) access technology, in particular to a method and device for accessing multiple optical network units (ONU, Optical Network Unit).

Background technique

In recent years, with the rapid development of the global access market and the rapid development of full-service operations, the existing PON technical standards have improved in terms of bandwidth requirements, business support capabilities, and performance improvements of access node equipment and supporting equipment. , are facing new upgrade requirements. At present, N Gigabit-Capable Passive Optical Network (NGPON, N Gigabit-Capable Passive Optical Network) has been in the commercial stage. NGPON includes two standards: NGPON1 and NGPON2; among them, NGPON2 is the next-generation technology of optical access network, mainly used for Realize the protocol function defined by ITU-T G.989.3; and can provide the bandwidth of 10G for uplink broadcast and 40G for downlink broadcast, and use optical splitter to realize the connection between one optical line terminal (OLT, Optical Line Terminal) and multiple ONUs . Among them, the topology structure of a typical PON system is defined in the ITU-T G.989.1 protocol, as shown in FIG. 1 .

In the PON system shown in Figure 1, the ONU, as a user terminal of the PON system, occupies an optical branch; due to the limitation of optical transmission attenuation, the optical branch ratio of each pair of wavelength channels limits the access to the PON system. The number of ONUs. For each ONU user, the bandwidth provided by the PON system is sufficient for the bandwidth requirements of ordinary users. Therefore, part of the bandwidth provided by the PON system may not be fully utilized, resulting in some hardware being idle. This causes a waste of hardware resources of the PON system, and also increases the networking cost of the PON system.

In order to solve the above problems, an existing solution is to place the ONU on a network node closer to the central office, and provide more user network interfaces (UNI, User Networks Interface) on the ONU to access more users . However, from the perspective of management, these multiple users share the same ONU, and as an OLT management entity, multiple users share one management channel, so this method is limited for user management.

Contents of the invention

In view of this, the embodiment of the present invention expects to provide a method and device for accessing multiple ONUs, which can realize the access and management of multiple ONUs on the ONU board of an optical splitter terminal, and solve the problems in the prior art. The number of ONU access is limited, and the bandwidth utilization rate is not high when the number of access is small, and the hardware is idle.

In order to achieve the above object, the technical solution of the embodiment of the present invention is achieved in this way:

The embodiment of the present invention provides a method for accessing a plurality of ONUs. More than one ONU is virtualized on an ONU board, and each virtual ONU corresponds to a serial number (SN, Serial Number) for identification and a registration identifier Register- ID is reported to the optical line terminal OLT in the registration phase, obtains the ONU identification ONU-ID, and maintains a piece of media access control (MAC, Media AccessControl) information for this virtual ONU; The method includes:

In the upstream direction, according to the bandwidth allocated by each virtual ONU, the transmission time slot of each virtual ONU is obtained, and the upstream burst burst data is assembled according to the allocated bandwidth, and the ONU-ID is sent to the OLT in the transmission time slot;

In the downlink direction, when the ONU frame data sent by the OLT is received, and after downlink frame delimitation, descrambling and forward error correction (FEC, Forward Error Correction) decoding, obtain the physical layer operation management maintenance (PLOAM, Physical Layer Operations And Maintenance) message, bandwidth information, GPON encapsulation mode (GEM, GPON Encapsulation Mode) payload data and optical network unit management control interface (OMCI, ONU Management and Control Interface) message; process the PLOAM message and OMCI message Afterwards, dynamically update the MAC information according to the OLT configuration;

In different processing units, each virtual ONU performs corresponding processing on its own PLOAM message, bandwidth information, GEM payload data and OMCI message.

In the above solution, the MAC information includes: ONU-ID of the virtual ONU, configuration identifier Alloc-ID, GEM port identifier Port-ID, equalization delay and key.

In the above scheme, in the different processing units, each virtual ONU carries out corresponding processing to its own PLOAM message, bandwidth information, GEM payload data and OMCI message, including:

Each virtual ONU filters the PLOAM message and the broadcast PLOAM message sent to the local virtual ONU according to the ONU-ID saved locally, and processes the PLOAM message and the broadcast PLOAM message;

Each virtual ONU filters the bandwidth of the local virtual ONU according to the Alloc-ID saved locally, and determines the bandwidth time slot of each virtual ONU according to the correspondence between the Alloc-ID and the ONU-ID;

After the demarcation of the downlink GEM data is completed, each virtual ONU filters the GEM packets sent to the local virtual ONU according to the locally saved Port-ID;

After decrypting and reassembling the GEM packet fragments, each virtual ONU filters the OMCI messages sent to the local virtual ONU according to the locally stored Port-ID, and processes the OMCI messages.

In the above scheme, update the configuration information of the virtual ONU according to the PLOAM message and broadcast PLOAM message content, and generate a corresponding upstream PLOAM message, and write the generated upstream PLOAM message into the buffer queue corresponding to each PLOAM channel, Waiting to transmit in the allocated time slot.

In the above solution, the multiple ONUs share the downlink receiving port and the uplink sending port of the passive optical network PON system, and are registered to the same group of downlink channels and uplink channels of the PON.

The embodiment of the present invention also provides a device for accessing multiple ONUs, the device comprising:

The configuration module is used to virtualize more than one ONU on an ONU board. Each virtual ONU corresponds to a copy of SN and Register-ID for identification. It is reported to the OLT during the registration phase to obtain the ONU-ID and register for the virtual ONU. Maintain a MAC information;

The upstream processing module is used to obtain the sending time slot of each virtual ONU according to the bandwidth allocated by each virtual ONU in the upstream direction, and assemble the upstream burst data according to the allocated bandwidth, and carry the ONU-ID in the sending time slot send to OLT;

The downlink processing module is used to obtain the PLOAM message, bandwidth information, GEM payload data and OMCI message; After the PLOAM message and OMCI message are processed, dynamically update the MAC information according to the OLT configuration;

The data and message processing module is used for each virtual ONU to process its own PLOAM message, bandwidth information, GEM payload data and OMCI message in different processing units.

In the above solution, the MAC information includes: ONU-ID, Alloc-ID, GEMPort-ID, equalization delay and key of the virtual ONU.

In the above scheme, the data and message processing module further includes:

The PLOAM message processing module is used to filter the PLOAM message and the broadcast PLOAM message sent to the local virtual ONU according to the ONU-ID stored locally, and process the PLOAM message and the broadcast PLOAM message;

The bandwidth information parsing module is used to filter the bandwidth of the local virtual ONU according to the Alloc-ID saved locally, and determine the bandwidth time slot of each virtual ONU according to the correspondence between the Alloc-ID and the ONU-ID;

The GEM payload data processing module is used to filter the GEM packets sent to the local virtual ONU according to the locally saved Port-ID after the demarcation of the downlink GEM data is completed;

The OMCI message processing module is used to filter the OMCI message sent to the local virtual ONU according to the locally saved Port-ID after decrypting and reassembling the GEM packet, and process the OMCI message.

In the above scheme, the PLOAM message processing module is also used to update the configuration information of the virtual ONU according to the PLOAM message and broadcast PLOAM message content, and generate a corresponding upstream PLOAM message, and write the generated upstream PLOAM message into the buffer queue corresponding to each PLOAM channel, waiting to be sent in the allocated time slot.

In the above solution, the multiple ONUs share the downlink receiving port and uplink sending port of the PON system, and are registered to the same group of downlink channels and uplink channels of the PON.

The access method and device for a plurality of ONUs provided by the embodiments of the present invention virtualize more than one ONU on an ONU board, and each virtual ONU corresponds to a copy of SN and Register-ID for identification, which is reported to OLT obtains the ONU-ID, and maintains a piece of MAC information for the virtual ONU; in the upstream direction, according to the bandwidth allocated by each virtual ONU, obtains the sending time slot of each virtual ONU, and assembles it according to the allocated bandwidth. The upstream burst data is sent to the OLT with the ONU-ID in the sending time slot; in the downstream direction, when the ONU frame data sent by the OLT is received, and after the downstream frame demarcation, descrambling and FEC decoding, respectively obtain PLOAM message, bandwidth information, GEM payload data and OMCI message; After the PLOAM message and OMCI message are processed, the MAC information is dynamically updated according to the OLT configuration; in different processing units, each virtual ONU pair belongs to itself The PLOAM message, bandwidth information, GEM payload data and OMCI message are processed accordingly. In this way, the access function of more ONUs can be realized on one optical network interface. Compared with the existing technology, under the same optical splitting ratio, more ONUs can be connected, so that the bandwidth can be fully utilized, so that in On the basis of not increasing the number of ONU boards, more OLT management entities are provided; moreover, the number of ONU accesses in the NGPON2 network is increased at a small hardware cost, and the networking cost of the entire network is reduced at the same time.

Description of drawings

FIG. 1 is a schematic diagram of a typical PON topology defined by the G.989.1 protocol in the prior art;

Fig. 2 is the realization flowchart of the access method of a plurality of ONUs of the embodiment of the present invention;

FIG. 3 is a schematic diagram of the functions and logical relationships of each component module of different processing units according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a PLOAM message processing flow after the expansion of the embodiment of the present invention;

Fig. 5 is the schematic diagram of the registration management flow chart of ONU of the embodiment of the present invention;

FIG. 6 is a schematic diagram of the composition and structure of multiple ONU access devices according to an embodiment of the present invention.

detailed description

In order to understand the characteristics and technical contents of the embodiments of the present invention in more detail, the implementation of the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. The attached drawings are only for reference and description, and are not intended to limit the present invention.

As shown in Figure 2, the implementation flow of the access method of a plurality of ONUs in the embodiment of the present invention comprises the following steps:

Step 200: Virtualize more than one ONU on one ONU board, each virtual ONU corresponds to a SN and Register-ID for identification, report to the OLT during the registration phase, obtain the ONU-ID, and maintain a copy for the virtual ONU MAC information;

Here, specifically how to virtualize multiple ONUs belongs to the prior art, and will not be repeated here.

Step 201: In the upstream direction, according to the bandwidth allocated by each virtual ONU, obtain the transmission time slot of each virtual ONU, assemble the upstream burst data according to the allocated bandwidth, and send the ONU-ID in the transmission time slot to the OLT;

Here, the multiple ONUs share the downlink receiving port and the uplink sending port of the PON system, and are registered to the same group of downlink channels and uplink channels of the PON.

Here, since the propagation delay and response time of each ONU are the same, they will be allocated equal equalization delay by the OLT. In this way, from the perspective of the sending side of the ONU, the bandwidth time slots allocated to each ONU do not affect each other, so that It can ensure that the data of each ONU is sent out accurately and without conflict.

Step 202: In the downlink direction, when receiving the ONU frame data sent by the OLT, and after downlink frame delimitation, descrambling and FEC decoding, obtain PLOAM message, bandwidth information, GEM payload data and OMCI message respectively; After the PLOAM message and OMCI message are processed, the MAC information is dynamically updated according to the OLT configuration;

Wherein, the MAC information includes: ONU-ID, Alloc-ID, GEM Port-ID, equalization delay and key of the virtual ONU; the purpose of maintaining the MAC information is to update the MAC information in time.

Step 203: In different processing units, each virtual ONU performs corresponding processing on its own PLOAM message, bandwidth information, GEM payload data and OMCI message.

Here, the different processing units include: the PLOAM message processing module in the OLT, the bandwidth information analysis module, the GEM payload data processing module, and the OMCI message processing module, the functions and logical relationships of the four constituent modules of the different processing units As shown in Figure 3.

In the different processing units, each virtual ONU carries out corresponding processing to its own PLOAM message, bandwidth information, GEM payload data and OMCI message, including:

Each virtual ONU filters the PLOAM message and the broadcast PLOAM message sent to the local virtual ONU according to the ONU-ID saved locally, and processes the PLOAM message and the broadcast PLOAM message;

Each virtual ONU filters the bandwidth of the local virtual ONU according to the Alloc-ID saved locally, and determines the bandwidth time slot of each virtual ONU according to the correspondence between the Alloc-ID and the ONU-ID;

Here, how to determine the bandwidth time slot of each virtual ONU according to the corresponding relationship between the Alloc-ID and the ONU-ID belongs to the prior art, and will not be repeated here.

After the demarcation of the downlink GEM data is completed, each virtual ONU filters the GEM packets sent to the local virtual ONU according to the locally saved Port-ID;

After decrypting and reassembling the GEM packet fragments, each virtual ONU filters the OMCI messages sent to the local virtual ONU according to the locally stored Port-ID, and processes the OMCI messages.

Here, in the downlink direction, the NGPON2 system maintains a set of unicast keys and multicast keys for each virtual ONU in normal working state, uses the different Register-IDs of each virtual ONU to generate its own master key, and follows the The process stipulated in the G.989.3 protocol independently generates and updates the key of each virtual ONU.

Wherein, the key is obtained according to the corresponding relationship between ONU-ID and Port-ID; when the GEM packet needs to be decrypted, the data can be decrypted according to the key index (key_index) and the key in the GEM header.

Among them, the key maintained by the NGPON2 system is also applicable to the encryption process of the uplink GEM packet, which will not be repeated here.

The technical scheme of the access method of a plurality of ONUs provided by the present invention is described in further detail below:

In the embodiment of the present invention, the extended PLOAM message processing flow is as shown in Figure 4. The NGPON2 system maintains a broadcast PLOAM message channel, and maintains an independent PLOAM message channel for each successfully registered virtual ONU. In Figure 4, the NGPON2 system divides the independent PLOAM message channel into n sub-channels according to time slots, and each sub-channel corresponds to an ONU-ID; when receiving a valid Assign ONU-ID, the NGPON2 system will correspondingly Add a PLOAM message sub-channel; that is, a virtual ONU corresponds to a PLOAM message sub-channel. Here, the effective Assign ONU-ID refers to the matching of the SN carried in the message and a certain local virtual ONU; in addition, the PLOAM message processing module independently processes the PLOAM messages of each virtual ONU, and responds to the downlink PLOAM message.

When receiving the unicast PLOAM message sent to a virtual ONU, the PLOAM message processing module can update the configuration information of this virtual ONU according to the content of the unicast PLOAM message, this configuration information includes Alloc-ID, key etc., and The corresponding upstream PLOAM message is written into the buffer queue of the virtual ONU; when the OLT requests to send a PLOAM message, the PLOAM message is read from the buffer queue, and the content of the read PLOAM message is filled into the upstream Burst and sent go out. Wherein, when the PLOAM sending flag in the bandwidth allocated to the virtual ONU is 1, it means that the OLT requires sending a PLOAM message; meanwhile, the state of the PLOAM cache queue in the virtual ONU can also be reported to the OLT through the Ind field in the Burst Header. When the PLOAM message sent by broadcast is received, the configuration information of all virtual ONUs is updated according to the content of the PLOAM message; finally, the performance of all PLOAM channels maintained is monitored, and the corresponding monitoring information is sent to the OLT through the OMCI channel.

Wherein, each virtual ONU is preset with a corresponding cache queue for storing PLOAM messages.

Here, among all the virtual ONUs, the content configured by the downlink broadcast message of one virtual ONU can be shared by other virtual ONUs, and the content configured by the unicast message belongs to a single virtual ONU.

Similar to the processing process of PLOAM messages, the NGPON2 system also provides an OMCI channel for each virtual ONU in normal working state, and the OMCI channel is distinguished by the default Port-ID of each virtual ONU. Each virtual ONU has a default Port-ID and Alloc-ID equal to the ONU-ID, which are used for receiving and sending by OMCI. In the downlink direction, after the GEM decrypts and reassembles, it filters the OMCI message sent to the local virtual ONU according to the default Port-ID saved locally, and processes the OMCI message accordingly; after parsing the content of the OMCI, update the configuration of the corresponding virtual ONU Information, such as the number of Port-IDs, encryption status, multicast key, etc., and generate corresponding OMCI data, and then cache the generated OMCI data into the default service container (TCONT, Transmission Containers) of the virtual ONU; when the virtual After receiving the assigned time slot of the default TCONT, the ONU reads out the OMCI data, encapsulates it into a GEM packet carrying the default Port-ID, and sends it out as the payload of the burst.

When required by the OLT, the monitoring information of the virtual ONU needs to be reported through the OMCI channel; and because the local virtual ONU shares equipment and downlink receiving data, the monitoring information on the equipment and downlink is shared by all ONUs. However, the upstream sending and PLOAM channels are independently monitored by each virtual ONU and reported to the OLT when necessary. Wherein, when the optical module is abnormally powered off, all virtual ONUs in the local working state will set the power-off alarm (Dying-gasp) bits in the upstream burst Ind domain to 1.

Here, the encryption status information of each Port-ID maintained by the system is obtained through the OMCI channel corresponding to the virtual ONU; when the virtual ONU sends upstream data to the OLT, the upstream data enters the OLT in the form of optical signals.

Fig. 5 is the registration management flow schematic diagram of the virtual ONU of the embodiment of the present invention, after receiving broadcast SN bandwidth in downlink bandwidth mapping (BWMAP, BandWidth Map), begin to check the state of local virtual ONU, promptly check whether there is virtual ONU unregistered, If it is checked that all the virtual ONUs have been registered, ignore the broadcast bandwidth, and only need to process the data and PLOAM bandwidth directly allocated to the virtual ONU; The received broadcast registration and ranging authorization are only sent to one of the virtual ONUs to ensure that only one of the local virtual ONUs responds to the registration request and reports to the corresponding SN during the quiet time during each window opening of the OLT. After the virtual ONU receives the assigned ONU-ID, the software system maintains an additional piece of virtual ONU information and adds a PLOAM and OMCI management channel. After the virtual ONU completes ranging and enters the O5 state, it sends the resolved SN request bandwidth to another virtual ONU, and starts the registration process of another virtual ONU. After all the virtual ONUs are registered, the SN request bandwidth is no longer resolved.

In order to realize the above method, the embodiment of the present invention also provides a plurality of ONU access devices, as shown in Figure 6, the device includes a configuration module 61, an uplink processing module 62, a downlink processing module 63, a data and message processing module 64 ;in,

The configuration module 61 is used to virtualize more than one ONU on an ONU board, and each virtual ONU corresponds to an SN and Register-ID for identification, reports to the OLT in the registration stage, obtains the ONU-ID, and registers for the virtual ONU ONU maintains a piece of MAC information;

The upstream processing module 62 is used to obtain the sending time slot of each virtual ONU according to the bandwidth allocated by each virtual ONU in the upstream direction, and assemble the upstream burst data according to the allocated bandwidth, and carry the ONU- ID sent to OLT;

The downlink processing module 63 is used for receiving the ONU frame data sent by the OLT in the uplink processing module 62 in the downlink direction, and after downlink frame delimitation, descrambling and FEC decoding, obtain the PLOAM message and bandwidth respectively information, GEM payload data and OMCI message; after the PLOAM message and OMCI message are processed, dynamically update the MAC information according to the OLT configuration;

The data and message processing module 64 is used for each virtual ONU to process its own PLOAM message, bandwidth information, GEM payload data and OMCI message in different processing units.

Wherein, the MAC information includes: ONU-ID, Alloc-ID, GEM Port-ID, equalization delay and key of the virtual ONU.

Here, the data and the message processing module 64 further include the following four submodules: PLOAM message processing module, bandwidth information analysis module, GEM payload data processing module and OMCI message processing module; wherein,

The PLOAM message processing module is used to filter the PLOAM message and the broadcast PLOAM message sent to the local virtual ONU according to the ONU-ID stored locally, and process the PLOAM message and the broadcast PLOAM message;

The bandwidth information parsing module is used to filter the bandwidth of the local virtual ONU according to the Alloc-ID saved locally, and determine the bandwidth time slot of each virtual ONU according to the correspondence between the Alloc-ID and the ONU-ID;

The GEM payload data processing module is used to filter the GEM packets sent to the local virtual ONU according to the locally saved Port-ID after the demarcation of the downlink GEM data is completed;

The OMCI message processing module is used to filter the OMCI message sent to the local virtual ONU according to the locally saved Port-ID after decrypting and reassembling the GEM packet, and process the OMCI message.

Wherein, the PLOAM message processing module is also used to update the configuration information of the virtual ONU according to the PLOAM message and broadcast PLOAM message content, and generate a corresponding upstream PLOAM message, and write the generated upstream PLOAM message into each In the buffer queue corresponding to the PLOAM channel, it is waiting to be sent in the allocated time slot.

Here, the multiple ONUs share the downlink receiving port and the uplink sending port of the PON system, and are registered to the same group of downlink channels and uplink channels of the PON.

In practical application, described configuration module 61, uplink processing module 62, downlink processing module 63 and data and message processing module 64 all can be positioned at the central processing unit (CPU, Central Processing Unit) on the ONU, microprocessor (MPU, Microprocessor) Processor Unit), digital signal processor (DSP, Digital Signal Processor), or field programmable gate array (FPGA, Field Programmable GateArray) and other implementations.

In the embodiment of the present invention, more than one ONU is virtualized on an ONU board, and each virtual ONU corresponds to a copy of SN and Register-ID for identification, which is reported to the OLT during the registration phase to obtain the ONU-ID, and maintain the ONU for the virtual ONU A piece of MAC information; in the upstream direction, according to the bandwidth allocated by each virtual ONU, the transmission time slot of each virtual ONU is obtained, and the uplink burst data is assembled according to the allocated bandwidth, and the ONU-ID is sent in the transmission time slot To OLT; in the downlink direction, when receiving the ONU frame data sent by the OLT, and after downlink frame delimitation, descrambling and FEC decoding, respectively obtain PLOAM message, bandwidth information, GEM payload data and OMCI message; After the PLOAM message and the OMCI message are processed, dynamically update the MAC information according to the OLT configuration; in different processing units, each virtual ONU carries out the PLOAM message, bandwidth information, GEM payload data and OMCI message belonging to itself Treat accordingly. In this way, the access function of more ONUs can be realized on one optical network interface. Compared with the existing technology, under the same optical splitting ratio, more ONUs can be connected, so that the bandwidth can be fully utilized, so that in On the basis of not increasing the number of ONU boards, more OLT management entities are provided; moreover, the number of ONU accesses in the NGPON2 network is increased at a small hardware cost, and the networking cost of the entire network is reduced at the same time.

The above description is only a preferred embodiment of the present invention, and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the within the protection scope of the present invention.

Claims (10)

1. A method for accessing a plurality of optical network units ONU, characterized in that, on an ONU board, more than one ONU is virtual, and each virtual ONU corresponds to a serial number SN and a registration mark Register-ID for identification , reporting to the optical line terminal OLT in the registration phase, obtaining the ONU identification ONU-ID, and maintaining a piece of media access control MAC information for the virtual ONU; the method includes: In the upstream direction, according to the bandwidth allocated by each virtual ONU, the transmission time slot of each virtual ONU is obtained, and the upstream burst burst data is assembled according to the allocated bandwidth, and the ONU-ID is sent to the OLT in the transmission time slot; In the downlink direction, when the ONU frame data sent by the OLT is received, and after downlink frame delimitation, descrambling and forward error correction (FEC) decoding, the physical layer operation management and maintenance PLOAM message, bandwidth information, and GPON encapsulation mode are respectively obtained GEM payload data and optical network unit management control interface OMCI message; After the PLOAM message and OMCI message are processed, dynamically update the MAC information according to the OLT configuration; In different processing units, each virtual ONU performs corresponding processing on its own PLOAM message, bandwidth information, GEM payload data and OMCI message. 2. The method according to claim 1, wherein the MAC information includes: ONU-ID of the virtual ONU, configuration identifier Alloc-ID, GEM port identifier Port-ID, equalization delay and key. 3. method according to claim 2, it is characterized in that, described in different processing units, each virtual ONU carries out corresponding processing to the PLOAM message, bandwidth information, GEM payload data and OMCI message belonging to oneself, comprising: Each virtual ONU filters the PLOAM message and the broadcast PLOAM message sent to the local virtual ONU according to the ONU-ID saved locally, and processes the PLOAM message and the broadcast PLOAM message; Each virtual ONU filters the bandwidth of the local virtual ONU according to the Alloc-ID saved locally, and determines the bandwidth time slot of each virtual ONU according to the correspondence between the Alloc-ID and the ONU-ID; After the demarcation of the downlink GEM data is completed, each virtual ONU filters the GEM packets sent to the local virtual ONU according to the locally saved Port-ID; After decrypting and reassembling the GEM packet fragments, each virtual ONU filters the OMCI messages sent to the local virtual ONU according to the locally stored Port-ID, and processes the OMCI messages. 4. method according to claim 3, it is characterized in that, described method also comprises: according to described PLOAM message and broadcast PLOAM message content update the configuration information of described virtual ONU, and produce corresponding uplink PLOAM message, the The uplink PLOAM message generated above is written into the buffer queue corresponding to each PLOAM channel, and waits to be sent in the allocated time slot. 5. The method according to claim 1, wherein the plurality of ONUs share a downstream receiving port and an upstream transmitting port of a passive optical network (PON) system, and are registered on the same group of downstream channels and upstream channels of the PON. 6. A kind of access device of a plurality of ONUs, it is characterized in that, described device comprises: The configuration module is used to virtualize more than one ONU on an ONU board. Each virtual ONU corresponds to a copy of SN and Register-ID for identification. It is reported to the OLT during the registration phase to obtain the ONU-ID and register for the virtual ONU. Maintain a MAC information; The upstream processing module is used to obtain the sending time slot of each virtual ONU according to the bandwidth allocated by each virtual ONU in the upstream direction, and assemble the upstream burst data according to the allocated bandwidth, and carry the ONU-ID in the sending time slot send to OLT; The downlink processing module is used to obtain the PLOAM message, bandwidth information, GEM payload data and OMCI message; After the PLOAM message and OMCI message are processed, dynamically update the MAC information according to the OLT configuration; The data and message processing module is used for each virtual ONU to process its own PLOAM message, bandwidth information, GEM payload data and OMCI message in different processing units. 7. The device according to claim 6, wherein the MAC information includes: ONU-ID, Alloc-ID, GEM Port-ID, equalization delay and key of the virtual ONU. 8. The device according to claim 7, wherein the data and message processing module further comprises: The PLOAM message processing module is used to filter the PLOAM message and the broadcast PLOAM message sent to the local virtual ONU according to the ONU-ID stored locally, and process the PLOAM message and the broadcast PLOAM message; The bandwidth information parsing module is used to filter the bandwidth of the local virtual ONU according to the Alloc-ID saved locally, and determine the bandwidth time slot of each virtual ONU according to the correspondence between the Alloc-ID and the ONU-ID; The GEM payload data processing module is used to filter the GEM packets sent to the local virtual ONU according to the locally saved Port-ID after the demarcation of the downlink GEM data is completed; The OMCI message processing module is used to filter the OMCI message sent to the local virtual ONU according to the locally saved Port-ID after decrypting and reassembling the GEM packet, and process the OMCI message. 9. The device according to claim 8, wherein the PLOAM message processing module is also used to update the configuration information of the virtual ONU according to the PLOAM message and broadcast PLOAM message content, and generate corresponding upstream PLOAM message, write the generated uplink PLOAM message into the cache queue corresponding to each PLOAM channel, and wait to be sent in the allocated time slot. 10 . The device according to claim 6 , wherein the plurality of ONUs share a downlink receiving port and an uplink sending port of the PON system, and are registered to the same group of downlink channels and uplink channels of the PON. 11 .