A service scheduling method and device

Abstract

The application discloses a service scheduling method and device, wherein the method comprises the steps of identifying deterministic services and non-deterministic services, and dividing the deterministic services and the non-deterministic services in different time slot areas; when a managed window is inserted, the window of the deterministic service is adjusted to before the managed window, so that the window of the deterministic service is before the window of the non-deterministic service and the window of the managed window. The application can avoid service forwarding time delay jitter caused by the managed window, thereby meeting the high requirement of industrial control scenarios on network determinacy.

Description

Technical Field

[0001] This invention relates to the field of passive optical network technology, and in particular to a service scheduling method and apparatus. Background Technology

[0002] In industrial control applications, there are high requirements for low latency and determinism in network forwarding. PON systems use a P2MP architecture, where different ONUs share the uplink in a time-sharing manner. Furthermore, PON systems incur management overhead; for example, management time slots must be allocated for new ONU registration, with slot size determined by network coverage. During the management window, all ONUs are prohibited from sending uplink services, causing jitter in uplink forwarding latency and failing to meet the deterministic network requirements of industrial control scenarios. Figure 3 The service labeled 2 is a deterministic service, scheduled every 30us. However, due to the insertion of the management window, the second scheduling of service 2 is delayed, introducing jitter in the forwarding latency. The jitter size is at least the size of the management window.

[0003] Therefore, how to avoid the jitter caused by the PON system forwarding the determined service to the upstream service before the management window is inserted into the determined service is a technical problem that urgently needs to be solved. Summary of the Invention

[0004] The main objective of this invention is to provide a service scheduling method and apparatus that can avoid service forwarding latency jitter caused by management window opening, thereby meeting the high deterministic requirements of industrial control scenarios for networks.

[0005] Firstly, this application provides a service scheduling method, wherein the method includes the following steps:

[0006] Identify deterministic and non-deterministic traffic, and classify deterministic and non-deterministic traffic into different time slot regions;

[0007] When a managed window is inserted, the window for the deterministic service is moved before the managed window, so that the window for the deterministic service precedes the window for the managed service and the window for the non-deterministic service.

[0008] In conjunction with the first aspect mentioned above, as an optional implementation method, the OLT automatically measures the distance to the connected ONUs after power-on to determine the distance between the nearest and farthest ONUs to the OLT;

[0009] The maximum network coverage area is determined based on the distance difference between the nearest and farthest ONUs to the OLT.

[0010] The window size for management is set based on the maximum coverage area of ​​the network.

[0011] In conjunction with the first aspect mentioned above, as an optional implementation method, after the ONU is powered on and registered, the OLT determines whether the currently configured window size meets the requirements based on the actual ranging value of the ONU.

[0012] If the requirements are not met, the window size of the management system will be adjusted accordingly.

[0013] In conjunction with the first aspect mentioned above, as an optional implementation method, deterministic and non-deterministic services are identified based on the protocol type and flow characteristics of the service, wherein the flow characteristics include: periodicity, byte length and duration, and rate.

[0014] Based on the different time slot regions, the deterministic and non-deterministic services are arranged in the corresponding time slot regions, and the deterministic services are placed before the non-deterministic services.

[0015] In conjunction with the first aspect mentioned above, as an optional implementation method, based on the deterministic and non-deterministic services identified by the ONU, the tcont types and configurations carried by each deterministic and non-deterministic service are marked.

[0016] The OLT receives the tcont type and configuration sent by the ONU and determines whether a specific service exists;

[0017] If so, the OLT will adjust the service scheduling time slot length, location, and number of scheduling times per frame according to the requirements.

[0018] In conjunction with the first aspect mentioned above, as an optional implementation method, it is determined whether the services carried by the ONU contain deterministic services that need to be deleted;

[0019] If so, release the tcont and gemport resources allocated to the service, and simultaneously release the scheduling time slots occupied by the service.

[0020] Secondly, this application provides a segmentation module for identifying deterministic and non-deterministic traffic, and dividing deterministic and non-deterministic traffic into different time slot regions;

[0021] A processing module is configured to, when a managed window is inserted, move the window for the deterministic service before the managed window, so that the window for the deterministic service precedes the window for the managed service and the window for the non-deterministic service.

[0022] In conjunction with the first aspect above, as an optional implementation, the processing module is also used to automatically measure the distance of the ONUs connected to the OLT after power-on, so as to determine the distance between the ONUs closest to and farthest from the OLT.

[0023] The maximum network coverage area is determined based on the distance difference between the nearest and farthest ONUs to the OLT.

[0024] The window size for management is set based on the maximum coverage area of ​​the network.

[0025] In conjunction with the first aspect above, as an optional implementation, the processing module is also used to determine, after the ONU powers on and registers, whether the window size of the currently configured management meets the requirements based on the actual ranging value of the ONU.

[0026] If the requirements are not met, the window size of the management system will be adjusted accordingly.

[0027] In conjunction with the first aspect above, as an optional implementation, the segmentation module is also used to identify deterministic and non-deterministic services based on the protocol type and flow characteristics of the service, wherein the flow characteristics include: periodicity, byte length and duration, and rate;

[0028] Based on the different time slot regions, the deterministic and non-deterministic services are arranged in the corresponding time slot regions, and the deterministic services are placed before the non-deterministic services.

[0029] This application provides a service scheduling method and apparatus. The method includes the steps of: identifying deterministic and non-deterministic services; dividing the deterministic and non-deterministic services into different time slot regions; and when a managed window is inserted, adjusting the window for the deterministic service to precede the managed window, so that the window for the deterministic service precedes the window for the non-deterministic service. This application can avoid the service forwarding latency jitter caused by managed windows, thereby meeting the high deterministic requirements of networks in industrial control scenarios.

[0030] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit the invention. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0032] Figure 1 This is a flowchart of a service scheduling method provided in the embodiments of this application;

[0033] Figure 2 This is a schematic diagram of a service scheduling device provided in an embodiment of this application;

[0034] Figure 3 This is a schematic diagram of the window opening for management provided in the embodiments of this application;

[0035] Figure 4 This is a schematic diagram illustrating the deterministic service adjustment provided in the embodiments of this application;

[0036] Figure 5 This is a flowchart of the ONU online process provided in the embodiments of this application;

[0037] Figure 6 This is a flowchart illustrating the new service time slot allocation process provided in the embodiments of this application;

[0038] Figure 7 This is a flowchart illustrating the service deletion process provided in the embodiments of this application. Detailed Implementation

[0039] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0040] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. Some of the block diagrams shown in the drawings represent functional entities and do not necessarily correspond to physically or logically independent entities.

[0041] The embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0042] Reference Figure 1 , Figure 1 The diagram shown is a flowchart of a service scheduling method provided by the present invention. Figure 1 As shown, the method includes the following steps:

[0043] Step S101: Identify deterministic and non-deterministic services, and divide deterministic and non-deterministic services into different time slot regions.

[0044] Specifically, deterministic and non-deterministic services are identified based on the protocol type and flow characteristics of the service, wherein the flow characteristics include: periodicity, byte length and duration, and rate;

[0045] Based on the different time slot regions, the deterministic and non-deterministic services are arranged in the corresponding time slot regions, and the deterministic services are placed before the non-deterministic services.

[0046] To illustrate this with an example, a PON system has a service monitoring unit (which can be located in the OLT or ONU). Deterministic services are generally small-byte, low-volume, and periodic, while other services are generally random and bursty. Therefore, the characteristics of the traffic can be used to determine whether a service is deterministic.

[0047] In addition, the ranking of deterministic and non-deterministic business transactions can be referenced. Figure 4 Sorting: Within a set allocation period, deterministic transactions are arranged before non-deterministic transactions. For example, if the allocation period is 30µs, deterministic transactions are sorted in the first 15µs and non-deterministic transactions are sorted in the last 15µs (the specific arrangement can be adjusted according to the actual situation).

[0048] In one embodiment, the OLT identifies new ONUs through the management channel. If a new ONU is found, the standard ONU registration process is performed. It's important to explain that new ONU registration requires the allocation of a management time slot. The size of the time slot depends on the network coverage, typically 250µs. During the management window opening, all ONUs are prohibited from sending uplink services. The management window opening can be understood as creating a time window for new ONUs to come online. In the uplink direction of the PON system, multiple ONUs send data uplink at different times under the control of the OLT. However, management information (ONU information) exists between the OLT and the ONUs. This information takes up a certain amount of time, and during the transmission of management information, all ONUs are prohibited from sending data. This is the source of jitter caused by the management window opening.

[0049] In one embodiment, before identifying deterministic and non-deterministic services, the method further includes: the OLT automatically measuring the distances of its connected ONUs after power-on to determine the distances to the nearest and farthest ONUs; determining the maximum network coverage area based on the distance difference between the nearest and farthest ONUs (the window size depends on the distance difference between the nearest and farthest ONUs); and setting the managed window size based on the maximum network coverage area (wherein the window size can be set relatively small depending on the actual application environment). After the ONUs power on and register, the OLT determines whether the currently configured managed window size meets the requirements based on the actual distance measurement value of the ONUs; if not, the managed window size is adjusted according to the needs (usually by reducing the window size).

[0050] It's important to note that the Serial Number-state (SN) is used by the OLT to send a Serial NumberRequest message to discover new ONUs and their serial numbers. Once the OLT discovers a new ONU, it assigns it an ONU-ID, and the ONU enters ranging mode. Furthermore, the management window can be understood as a silent window, where all online ONUs refrain from sending data, allowing newly connected ONUs to send their SN information.

[0051] Step S102: When a managed window is inserted, the window for the deterministic service is moved before the managed window, so that the window for the deterministic service is before the managed window and the window for the non-deterministic service.

[0052] Specifically, the OLT allocates time slots, allowing each ONU to send uplink packets according to these slots. However, management information is periodic and is inserted into the ONU's data transmission process, potentially preempting the ONU's packet transmission time slots. In other words, management window openings are randomly inserted before deterministic and non-deterministic services. If inserted before deterministic services, jitter and delay will occur because deterministic services have requirements for low latency and low jitter in forwarding. In this case, deterministic services following the management window are moved before the management window to allow data transmission (for example, if there are four deterministic services after the management window, these four deterministic services are moved before the management window so that the deterministic service's window opens before the non-deterministic service's window). See the processing method for reference. Figure 4 .

[0053] If inserted after deterministic business and before nondeterministic business, the nondeterministic business has lower requirements for jitter and latency, so the management window opening operation can be performed first.

[0054] In one embodiment, for example, there are three services, A, B, and C, corresponding to three ONUs, namely 1, 2, and 3. A is a deterministic service, B is a non-deterministic service, and C is a new ONU. When scheduling service A, the OLT will open a window for ONU1 to allow service A to be transmitted. The same applies to B and C. Therefore, opening a window for deterministic services and opening a window for non-deterministic services refers to opening a time window to send data to the OLT. It should also be noted that service C cannot be scheduled before service A; that is, service A has the highest priority, while B and C have equal priority.

[0055] Reference Figure 2 , Figure 2 The diagram shown is a schematic of a service scheduling device provided by the present invention. Figure 2 As shown, the device includes:

[0056] Segmentation module 201: It is used to identify deterministic and non-deterministic services and to divide deterministic and non-deterministic services into different time slot regions.

[0057] Processing module 202: When a managed window is inserted, it adjusts the window of the deterministic service to be before the managed window, so that the window of the deterministic service is before the window of the managed service and the window of the non-deterministic service.

[0058] Furthermore, in one possible implementation, the processing module is also used for the OLT to automatically measure the distance of the connected ONUs after power-on, so as to determine the distance between the nearest and farthest ONUs to the OLT.

[0059] The maximum network coverage area is determined based on the distance difference between the nearest and farthest ONUs to the OLT.

[0060] The window size for management is set based on the maximum coverage area of ​​the network.

[0061] Furthermore, in one possible implementation, the processing module is also used to determine whether the currently configured window size meets the requirements based on the actual ranging value of the ONU after the ONU is powered on and registered.

[0062] If the requirements are not met, the window size of the management system will be adjusted accordingly.

[0063] Furthermore, in one possible implementation, the segmentation module is also used to identify deterministic and non-deterministic services based on the protocol type and flow characteristics of the service, wherein the flow characteristics include: periodicity, byte length and duration, and rate.

[0064] Based on the different time slot regions, the deterministic and non-deterministic services are arranged in the corresponding time slot regions, and the deterministic services are placed before the non-deterministic services.

[0065] Furthermore, in one possible implementation, the processing module is also used to mark the tcont type and configuration of each deterministic and non-deterministic service based on the deterministic and non-deterministic services identified by the ONU.

[0066] The OLT receives the tcont type and configuration sent by the ONU and determines whether a specific service exists;

[0067] If so, the OLT will adjust the service scheduling time slot length, location, and number of scheduling times per frame according to the requirements.

[0068] Furthermore, in one possible implementation, the processing module is also used to determine whether the services carried by the ONU contain deterministic services that need to be deleted;

[0069] If so, release the tcont and gemport resources allocated to the service, and simultaneously release the scheduling time slots occupied by the service.

[0070] Reference Figure 3 , Figure 3 The diagram shown is a schematic representation of the window opening mechanism provided by the present invention. Figure 3 As shown:

[0071] ONU registration requires the allocation of management time slots. The size of these time slots depends on the network coverage area, typically 250µs. When a management window is open, all ONUs cannot send uplink services, causing jitter in the uplink forwarding latency of the PON system. This fails to meet the deterministic network requirements of industrial control scenarios. Figure 3 Service number 2 is a deterministic service, scheduled every 30us. However, due to the insertion of the management window, the second scheduling of service 2 is delayed, which introduces jitter in forwarding latency. The jitter size is at least the size of the management window.

[0072] Reference Figure 4 , Figure 4 The image shown is a qualitative business adjustment illustration provided by the present invention, such as... Figure 4 As shown:

[0073] Based on a set allocation period, deterministic and non-deterministic transactions are sorted, with deterministic transactions preceding non-deterministic transactions. In the diagram, dashed lines 1 and 2 represent deterministic transactions, which are implemented as non-deterministic transactions. (Refer to...) Figure 3 If the management window opens before the deterministic service window, then the deterministic service window is moved forward to ensure that the management window opens after the deterministic service window. That is, services labeled 1 and 2 are deterministic services, scheduled every 30µs to ensure that the management window opens after the deterministic service window, thus avoiding jitter introduced by the forwarding latency of the deterministic service.

[0074] Reference Figure 5 , Figure 5 The diagram shown is a flowchart of the ONU online process provided by this invention. Figure 5 As shown:

[0075] The system pre-configures window size templates for different ONU ranging values, such as 1KM, 2KM, 5KM, 10KM, and 20KM. The system's window size configuration must accommodate the maximum ONU distance in the PON network. After an ONU powers on and registers, the OLT determines whether the currently configured window size meets the requirements based on the ONU ranging value. If not, it adjusts the settings according to the pre-configured template. Each PON interface has a window size template set based on the furthest distance of its connected ONUs. By default, a template for the maximum distance can be configured to ensure all ONUs can register correctly. After ONU registration, the template can be adjusted based on the actual ranging. In industrial environments, where coverage is generally small, the window size can be reduced according to the actual situation.

[0076] Specifically, after powering on, the OLT automatically measures the distance to its connected ONUs, determining the distances to the nearest and farthest ONUs, and thus determining the network coverage area. Based on this coverage area, the size of the management window can be set to accurately identify the location of the management window. Understandably, by default, the OLT's management window size supports a coverage area of ​​20km, which makes the management window relatively large. However, in industrial scenarios, such a large coverage area is not necessary. Therefore, the window size needs to be adjusted according to the actual range. A smaller management window makes it easier for the OLT to determine the location of the management window, thus reducing the impact on network jitter.

[0077] Reference Figure 6 , Figure 6 The diagram shown is a flowchart of the new service time slot allocation provided by the present invention. Figure 6 As shown:

[0078] Based on the deterministic and non-deterministic services identified by the ONU, the types and configurations of the tconts carried by each deterministic and non-deterministic service are marked (Tcont is the unit of service carried in the PON system, and marking it indicates that the service carried by the tcont is a deterministic service); the OLT receives the tcont types and configurations sent by the ONU and determines whether a deterministic service exists; if so, the OLT adjusts the scheduling slot length, position, and number of scheduling times per frame for that service according to requirements.

[0079] Specifically, after the ONU goes online, system configuration only requires adding regular services and initial configuration of services upon ONU launch. All services are regular best-effort services. During service operation, the ONU automatically identifies and determines the type of service, mainly through the service protocol type (e.g., Modbus, Profinet, EtherCAT, CAN, CC-link, etc.) and the service flow characteristics (e.g., periodicity, byte length, duration, rate, etc.). After determining the service type, the ONU packages the tcont corresponding to the service and related service parameters (service type, required bandwidth, latency characteristics, etc.) and reports them to the OLT through the management channel. The OLT adjusts the service scheduling time slot according to the requirements, configuring the time slot length, single-frame scheduling count, and scheduling position within the 125us scheduling cycle as required (each service time slot is allocated by the OLT, so after identifying deterministic services, the OLT can adjust the position of the time slot allocated to deterministic services to ensure that it is not interfered with by managed windowing and non-deterministic service windowing).

[0080] Reference Figure 7 , Figure 7 The diagram shown is a flowchart of the service deletion process provided by the present invention. Figure 7 As shown:

[0081] For deterministic services that need to be deleted, the service deletion action occurs when the service is deleted manually or when the ONU is authorized manually. When deleting, it is first determined whether the services carried by the ONU include deterministic services. If they do, only the tcont and gemport resources allocated to the service are released. At the same time, the deterministic scheduling time slots occupied by the service also need to be released.

[0082] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A traffic scheduling method, characterized by, include: Based on the protocol type and flow characteristics of the service, deterministic and non-deterministic services are identified, wherein the flow characteristics include: periodicity, byte length and duration, and rate; deterministic and non-deterministic services are divided into different time slot regions, and based on the different time slot regions, the deterministic and non-deterministic services are arranged in the corresponding time slot regions, with the deterministic services placed before the non-deterministic services; When a managed window is inserted, the window for the deterministic service is moved before the managed window, so that the window for the deterministic service precedes the window for the managed service and the window for the non-deterministic service.

2. The method according to claim 1, characterized in that, Before identifying deterministic and non-deterministic transactions, the method further includes: After powering on, the OLT automatically measures the distance to the connected ONUs to determine the distance between the nearest and farthest ONUs. The maximum network coverage area is determined based on the distance difference between the nearest and farthest ONUs to the OLT. The window size for management is set based on the maximum coverage area of ​​the network.

3. The method according to claim 2, characterized in that, Also includes: After the ONU is powered on and registered, the OLT determines whether the currently configured window size meets the requirements based on the ONU's actual ranging value. If the requirements are not met, the window size of the management system will be adjusted accordingly.

4. The method according to claim 1, characterized in that, Also includes: Based on the deterministic and non-deterministic services identified by the ONU, the types and configurations of the tcont carried by each deterministic and non-deterministic service are marked. The OLT receives the tcont type and configuration sent by the ONU and determines whether a specific service exists; If so, the OLT will adjust the service scheduling time slot length, location, and number of scheduling times per frame according to the requirements.

5. The method according to claim 4, characterized in that, It also includes a deletion process for deterministic business transactions, which includes: Determine whether the services carried by the ONU include any deterministic services that need to be deleted; If so, release the tcont and gemport resources allocated to the service, and simultaneously release the scheduling time slots occupied by the service.

6. A service scheduling apparatus for implementing the service scheduling method as described in any one of claims 1-5, characterized in that, include: The segmentation module is used to identify deterministic and non-deterministic services based on the protocol type and flow characteristics of the services, wherein the flow characteristics include: periodicity, byte length and duration, and rate; to segment deterministic and non-deterministic services into different time slot regions; and based on the segmented different time slot regions, to arrange the deterministic and non-deterministic services in the corresponding time slot regions and to place the deterministic services before the non-deterministic services. A processing module is configured to, when a managed window is inserted, move the window for the deterministic service before the managed window, so that the window for the deterministic service precedes the window for the managed service and the window for the non-deterministic service.

7. The apparatus according to claim 6, characterized in that: The processing module is also used to automatically measure the distance of the ONUs connected to the OLT after power-on, so as to determine the distance between the ONUs closest to and farthest from the OLT. The maximum network coverage area is determined based on the distance difference between the nearest and farthest ONUs to the OLT. The window size for management is set based on the maximum coverage area of ​​the network.

8. The apparatus according to claim 7, characterized in that: The processing module is also used to determine whether the window size of the currently configured management meets the requirements based on the actual ranging value of the ONU after the ONU is powered on and registered. If the requirements are not met, the window size of the management system will be adjusted accordingly.

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