CN101079801A - Method for transmitting uplink control packet in Gbit passive optical network system - Google Patents

Abstract

The invention discloses a method for transmitting an uplink control message in a gigabit passive optical network system. An optical network terminal (ONT) transmits a service flow received from a user side to an optical line terminal (OLT), and the ONT Classify the service flow received from the user side, mark the control message and data message with different GEM Port-ID of the PON encapsulation mode port ID and transmit them separately, and control the message during transmission files are processed with high priority. The method provided by the invention enables the control message to be transmitted in time and ensures the service quality of the control message.

Description

Method for transmitting uplink control message in gigabit passive optical network system

technical field

The present invention relates to optical access technology, in particular to a method for transmitting uplink control messages in a Giga-bit Passive Optical Network (GPON) system.

Background technique

The current broadband access technology is mainly divided into copper wire access technology and optical access technology. Among them, the access network realized by optical access technology is called Optical Access Network (OAN). One implementation technology of optical access network is passive optical network (Passive Optical Network, PON) technology, which is an optical access technology for point-to-multipoint transmission.

Referring to the PON system structure shown in Figure 1, the PON system mainly includes three parts: Optical Line Terminator (OLT), Optical Distribution Network (ODN) and Optical Network Unit (ONU). Among them, the OLT is used to provide the network side interface (SNI) for the OAN, and connect one or more ODNs; the ODN is used to transmit the downlink data of the OLT to each ONU through optical branching, and transmit the uplink data of the ONU to the OLT; ONU is used to provide user side interface (UNI) for OAN, and is connected with ODN. If the ONU can provide user port functions such as Ethernet (Ethernet) user port or ordinary telephone service (Plain Old Telephone Service, POTS) user port at the same time, it is called an optical network terminal (Optical Network Terminator, ONT). For the convenience of description, the ONU and ONT are collectively referred to as ONT in this document.

Figure 2a and Figure 2b are the schematic diagrams of PON downlink data transmission and PON uplink data transmission respectively. Generally, the downlink traffic of OLT is transmitted to ONT through TDM (Time Division Multiplexing) broadcast, and each ONT receives the traffic on demand. ; The upstream flow of the ONT is transmitted to the OLT through TDMA (Time Division Multiple Access).

GPON is an evolved version of PON, which can support higher speed requirements. Figure 3 shows the protocol stack structure of GPON. The GPON Transmission Convergence Layer (GPON Transmission ConvergenceLayer, GTC) is responsible for transferring data from Asynchronous Transfer Mode Client (ATM Client) or Gigabit Passive Optical Network Encapsulation Method (GPON Encapsulation Method) Client, GEM Client) encapsulates the business data received into GTC TC frames and sends them to the GPON Physical Media Dependent Layer (GPM); the GPM layer is responsible for the transmission of GTC TC frames on the optical fiber; the operation, maintenance and management of the physical layer (PhysicalLayer Operation Administration Management, PLOAM) is responsible for the operation, management, and maintenance of the GPON physical layer; the OLT realizes the control of the ONT through the ONT Management and Control Interface (OMCI), and the data of OMCI is passed through OMCI like ordinary business data. The adapter (OMCI Adapter) is encapsulated into ATM cells or GEM data blocks for transmission. The GTC layer provides two encapsulation methods for service data, namely ATM encapsulation and GEM encapsulation. The ATM encapsulation method encapsulates service data in 53-byte ATM cells for transmission, and transmits fixed-length ATM cells. The GEM encapsulation method is For variable-length encapsulation, it supports changing the length of the GEM encapsulated frame according to the length of the service data frame.

The GTC layer includes two sublayers: TC Adaptation Sub-layer and GTC Framing Sub-layer. In the downlink direction, the ATM TC Adapter (ATM TC Adapter) on the TC adaptation sublayer cuts the service data received from the ATM Client into ATM cells, or the GEM TC Adapter (GEM TC Adapter) on the TC adaptation sublayer Cut the business data received from GEMClient into GEM data blocks and send them to the GTC frame sublayer; the GTC frame sublayer adds the GTC TC frame header before the ATM cells or GEM data blocks according to the control information of PLOAM to form a complete GTC TC Frames are sent to the GPM layer. In the uplink direction, the GTC frame sublayer removes the frame header information from the GTC TC frame received from the GPM layer and sends it to the TC adaptation sublayer for processing; the TC adaptation sublayer converts the ATM cells or GEM data blocks in the GTC TC frame Assemble into corresponding business data and send to ATM Client or GEM Client.

The basic control unit in the GPON GTC layer is the transmission container (T-CONT), and the OLT allocates a transmission container allocation identifier (Alloc-ID) for each T-CONT. Refer to the GEM multiplexing structure shown in Figure 4. In the GEM encapsulation mode, the T-CONT internally multiplexes service flows through the Gigabit PON encapsulation mode port (GEM Port), and each GEM Port is assigned a GEM Port ID (GEM Port-ID); in the ATM encapsulation mode, T-CONT internally multiplexes service flows through permanent virtual channels/permanent virtual channels (PVP/PVC), and each PVP/PVC is assigned a virtual channel ID/ Virtual channel identification (VPI/VCI). The DBA control module (DBA Control) in the GTC layer realizes the dynamic bandwidth allocation to each ONT by monitoring and managing all T-CONTs.

In the GPON system, each ONT can access one or more multicast users. Referring to the multicast service transmission schematic diagram shown in Figure 5, when a multicast user wants to receive a multicast service, he first initiates an Internet Group Management Protocol (IGMP) request message; after the OLT receives the IGMP request message of the multicast user, it performs authentication. Authorization processing, and after the authentication is passed, apply to the multicast source server on the network side for the multicast program stream specified by the user; the multicast source server sends the specified multicast program stream to the OLT; the OLT then uses the natural broadcast of the GPON system The channel copies the multicast service flow to each ONT, and the ONT then copies the multicast service flow to each multicast user. At the same time, the OLT will regularly and proactively send IGMP query messages to the multicast users on the ONT side to detect whether the multicast users are online. Both the IGMP request message and the IGMP query message can be called IGMP control messages. In the GPON standard, the downlink multicast service flow is marked with a specific GEM Port-ID and sent to the ONT side, which is completely separated from the downlink unicast service flow. In the uplink direction, the IGMP control packets of the multicast users are generally transmitted together with data services such as Internet access. Due to the low priority of data services such as Internet access, the bandwidth cannot be effectively guaranteed, and it is easy to cause IGMP control messages to be processed in time, and the quality of service (QoS) of IGMP control messages cannot be guaranteed, which directly affects multicast services. performance.

The above only elaborates on the uplink transmission of the IGMP control message. In fact, for other uplink control messages such as the PPP protocol (PPPoE) control message carried by the large network, the Dynamic Host Configuration Protocol (DHCP) control message, Session Initiation Protocol (SIP) control packets and the like also have the above-mentioned problems. That is to say, in the GPON system, due to the limitation of the transmission mode of the control message, the uplink control message cannot be transmitted in time, and the QoS of the control message cannot be guaranteed, thereby affecting the performance of the service.

Contents of the invention

In view of this, the purpose of the present invention is to provide a method for transmitting uplink control messages in a gigabit passive optical network system to ensure the QoS of the control messages.

In order to achieve the above object, the technical scheme provided by the invention is as follows:

The ONT transmits the service flow received from the user side to the OLT, classifies the service flow received from the user side on the ONT, and marks the control message and data message with different GEM Port-IDs for transmission separately. And process the control message with high priority during transmission.

Wherein, the high-priority processing of the control message in the transmission process includes: high-priority processing of the control message on the ONT;

Or include: performing high-priority processing on the control message on the OLT;

Or include: performing high-priority processing on the control message on the ONT and the OLT.

Wherein, the high-priority processing of the control message on the ONT includes: the ONT maps the control message to the high-priority queue of the T-CONT.

The ONT maps the control message to the high priority queue of the T-CONT as: the ONT maps the control messages of all users to the high priority queue of the same T-CONT;

Alternatively, the ONT maps the control packets of each user to the high-priority queue of the T-CONT corresponding to each user.

Wherein, the high-priority processing of the control message on the ONT includes: the ONT maps the control message to the queue of the T-CONT, and sets the type of the T-CONT where the control message is located to Type 2.

The ONT sets the type of the T-CONT where the control message is located as Type 2 to be: the ONT sets the type of the T-CONT where the control messages of all users are located as Type 2;

Alternatively, the ONT sets the type of the T-CONT where the control packets of each user resides to Type2.

Wherein, the high-priority processing of the control message on the OLT includes: the OLT sends the received control message to the network side, and sets the priority of the control message to high.

The setting the priority of the control message as high includes: setting the 802.1p of the control message as high priority.

Wherein, the control message is an IGMP control message, or a PPPoE control message, or a DHCP control message, or a SIP control message.

It can be seen that the present invention realizes the separate transmission of the control message and the data message by classifying the service flow received from the user side and marking the control message and the data message with different GEM Port-IDs respectively. And by performing high-priority processing on the control message during the transmission process, the uplink control message can be transmitted in time, ensuring the QoS of the control message, thereby ensuring the performance of the service.

Description of drawings

FIG. 1 is a schematic structural diagram of a PON system in the prior art;

Figure 2a is a schematic diagram of PON downlink data transmission in the prior art;

FIG. 2b is a schematic diagram of PON uplink data transmission in the prior art;

Fig. 3 is the structural representation of GPON protocol stack in the prior art;

FIG. 4 is a schematic structural diagram of a GEM multiplexing mode in the prior art;

FIG. 5 is a schematic diagram of multicast service transmission in a GPON system in the prior art;

Fig. 6 is a schematic diagram of a processing model of a control message in the present invention;

Figure 7a is a schematic diagram of a T-CONT allocation model in an embodiment of the present invention;

Fig. 7b is a schematic diagram of T-CONT allocation model 2 in the embodiment of the present invention;

Fig. 7c is a schematic diagram of T-CONT allocation model 3 in the embodiment of the present invention;

Fig. 7d is a schematic diagram of T-CONT allocation model 4 in the embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples.

The basic idea of the present invention is: flow classification is carried out on the business flow that receives from user side on ONT, control message and data message are marked with different GEM Port-ID respectively and transmit separately, and in the transmission process control Packets are processed with high priority.

Wherein, the high-priority processing of the control message in the transmission process can be the high-priority processing of the control message on the ONT, or the high-priority processing of the control message on the OLT, Alternatively, high-priority processing of the control message may also be performed on the ONT and the OLT at the same time.

As shown in Figure 6, after the ONT receives the service flow from the user side, it first classifies the service flow (Classify), divides the control message and the data message into different service flows, and marks them with different GEM Port-IDs respectively. Then map the control message and data message to the T-CONT queue (PQ/Scheduling) and send it to the OLT through the passive optical network physical interface (PON IF), that is, the control message and data message The transmission is performed separately, and the control message is processed with high priority during transmission.

Wherein, the manners of performing high-priority processing on the control message mainly include the following three types:

1. If the control message and the data message are allocated to the same T-CONT, the ONT maps the control message to the high priority queue of the T-CONT and sends it to the OLT. In this way, the T-CONT can ensure priority scheduling of the control message when scheduling the priority of the queue, that is, the T-CONT sends the control message to the OLT preferentially.

2. If the control message and the data message are allocated to different T-CONTs, the ONT maps the control message to the queue of the T-CONT, and sets the type (Type) of the T-CONT where the control message is located to Type 2 with guaranteed bandwidth. In this way, during the transmission process of the control message and the data message, the bandwidth of the control message can be guaranteed.

3. After the OLT receives the service flow from the ONT, it identifies the control message and the data message according to the GEM Port-ID, and then performs different QoS to ensure that the control message is processed first.

Wherein, the identification of the control message and the data message according to the GEM Port-ID can be realized by pre-setting the ONT and the OLT. For example, the ONT marks the control message with a specific GEM Port-ID, and the OLT receives a specific GEM Port-ID. After the business flow, it will be processed first.

If the OLT needs to transparently transmit the control message to the network side, the OLT sets the priority of the control message to high, such as setting the 802.1p of the control message to a high priority, and transmits the control message to the network side.

Wherein, the control message is an IGMP control message, a PPPoE control message, a DHCP control message, or a SIP control message.

It should be noted that the above three methods can be used alone or in combination. For example, use only one method at a time; or use method 1 and method 3 at the same time; or use method 2 and method 3 at the same time, etc.

In the GPON Common Technical Standard (CTS), a variety of different application methods are specified for the T-CONT allocation of ONTs. For details, please refer to Figure 7a, Figure 7b, Figure 7c and Figure 7d. In Figure 7a, only one T-CONT is allocated to each ONT; in Figure 7b, one T-CONT is allocated to each user of each ONT; in Figure 7c, one T-CONT is allocated to each type of service of each ONT; In Fig. 7d, one T-CONT is allocated for each type of business of each ONT and each user.

The following takes the IGMP control message as an example, and combines the four T-CONT allocation and application modes shown in Figure 7a, Figure 7b, Figure 7c and Figure 7d respectively, to describe the transmission of IGMP control messages and data messages on the ONT in detail illustrate.

As shown in Figure 7a, the ONT maps all user control packets to the same high-priority queue of the T-CONT. The specific process is as follows: For all users, after the ONT receives the service flow from the user side, it first classifies the service flow, divides the IGMP control message and data message into different service flows, and marks them with different GEM Port-IDs , and map IGMP control packets and data packets to different priority queues of the same T-CONT, and then send them to the OLT. Wherein, the priority of the IGMP control message is higher than that of the data message, that is, the IGMP control message is mapped to the high-priority queue of the T-CONT.

Referring to Fig. 7b, the ONT maps the control packets of each user to the high-priority queue of the T-CONT corresponding to each user. The specific process is as follows: For each user, after ONT receives the service flow from the user side, it first classifies the service flow, divides the IGMP control message and data message into different service flows, and marks them with different GEM Port-IDs , and map IGMP control packets and data packets to different priority queues of the same T-CONT, and then send them to the OLT. Wherein, the priority of the IGMP control message is higher than that of the data message, that is, the IGMP control message is mapped to the high-priority queue of the T-CONT.

Figure 7a is similar to Figure 7b for the processing of business flows, the difference is that the business flows of all users in Figure 7a are mapped to the same T-CONT, while the business flows of each user in Figure 7b are mapped to the same T-CONT On the T-CONT corresponding to each user.

As shown in Figure 7c, the ONT sets the type of T-CONT where all user control packets are located to Type 2. The specific process is as follows: For all users, after the ONT receives the service flow from the user side, it first classifies the service flow, divides the IGMP control message and data message into different service flows, and marks them with different GEM Port-IDs , and map the IGMP control message and data message to different T-CONT queues, and then send them to the OLT, and set the T-CONT type corresponding to the IGMP control message to Type 2.

As shown in Figure 7d, the ONT sets the type of T-CONT where the control packets of each user are located to Type 2. The specific process is as follows: For each user, after ONT receives the service flow from the user side, it first classifies the service flow, divides the IGMP control message and data message into different service flows, and marks them with different GEM Port-IDs , and map the IGMP control message and data message to different T-CONT queues, and then send them to the OLT, and set the T-CONT type corresponding to the IGMP control message to Type 2.

Figure 7c is similar to Figure 7d in the processing of business flows. The difference is that in Figure 7c, the same type of business flows of all users are mapped to the same T-CONT, while in Figure 7d, the same type of business flows of each user Streams are respectively mapped to T-CONTs corresponding to each user.

It should be noted that the method provided by the present invention is not only applicable to IGMP control messages, but also applicable to other control messages, such as PPPoE control messages, DHCP control messages, SIP control messages and the like.

It can be seen that the method provided by the present invention enables the uplink control message to be transmitted in time and ensures the Qos of the control message.

The purpose, technical solutions and beneficial effects of the present invention have been further described in detail above. It should be understood that the above description is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. shall be included in the protection scope of the present invention.

Claims (11)

1, the method for transmitting uplink control packet in a kind of Gbit passive optical network system, Optical Network Terminal ONT will be transferred to optical line terminal OLT from the Business Stream that user side is received, it is characterized in that, on ONT, the Business Stream of receiving from user side is carried out traffic classification, the control message is stamped different gigabit passive optical network encapsulation mode port-mark GEM Port-ID respectively with data message separately transmit, and in transmission course, the control message is carried out high priority and handle.

2, method according to claim 1 is characterized in that, describedly in transmission course the control message is carried out high priority and handles and to comprise: on ONT the control message is carried out high priority and handle.

3, method according to claim 1 is characterized in that, describedly in transmission course the control message is carried out high priority and handles and to comprise: on OLT the control message is carried out high priority and handle.

4, method according to claim 1 is characterized in that, describedly in transmission course the control message is carried out high priority and handles and to comprise: on ONT and OLT the control message is carried out high priority and handle

5, according to claim 2 or 4 described methods, it is characterized in that, describedly on ONT the control message is carried out high priority and handle and to comprise: ONT will control in the high-priority queue that message is mapped to transmission container T-CONT.

6, method according to claim 5 is characterized in that, described ONT will control message and be mapped to T-(in the high-priority queue of ONT be: ONT is mapped to all users' control message in the high-priority queue of same T-CONT;

Perhaps be: ONT is mapped to the T-CO corresponding with each user respectively with each user's control message) in the high-priority queue of NT.

7, according to claim 2 or 4 described methods, it is characterized in that, describedly on ONT the control message is carried out high priority and handle and to comprise: ONT will control in the formation that message is mapped to T-CONT, and the type Type that controls message place T-CONT is set to Type 2.

8, method according to claim 7 is characterized in that, the type that described ONT controls message place T-CONT is set to Type 2 and is: the type of all users' of ONT control message place T-CONT is set to Type 2;

Perhaps be: ONT all is set to Type2 with the type of each user's control message place T-CONT.

9, according to claim 3 or 4 described methods, it is characterized in that, describedly on OLT the control message is carried out high priority and handle and to comprise: the control message that OLT will receive sends to network side, and controls priority of messages and be set to height.

10, method according to claim 9 is characterized in that, the described priority of messages of controlling is set to height and comprises: the 802.1p that controls message is set to high priority.

11, according to each described method of claim 1 to 10, it is characterized in that described control message is controlled message or is that SIP (Session Initiation Protocol) is controlled message for Internet Group Management Protocol IGMP control message or for PPP over Ethernet PPPoE control message or for dynamic host configuration protocol DHCP.

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