WO2012083669A1

WO2012083669A1 - Method and apparatus for switching between primary-standby devices based on access gateway

Info

Publication number: WO2012083669A1
Application number: PCT/CN2011/076512
Authority: WO
Inventors: 李博
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-12-23
Filing date: 2011-06-28
Publication date: 2012-06-28
Also published as: CN102025551A

Abstract

Disclosed are a method and an apparatus for switching between primary-standby devices based on an access gateway, wherein the method includes: configuring N standby devices for one primary device bearing services, wherein; when abnormality occurs on the primary device, selecting an available standby device from the N standby devices; using the selected standby device to substitute for the primary device to bear the service. The present invention solves the instability problem due to the 1:1 relation between the primary device and the standby device in the related art, and enables smooth transitions of system resource and service application switch when the system is abnormal.

Description

The present invention relates to the field of communications, and in particular to a method and apparatus for switching between primary and backup devices based on an access gateway (Access Gateway, AG for short). BACKGROUND In an AG system, a system needs to have a main control board MP (Main Processor), which is responsible for planning and allocating system resources for various services. At the same time, various user versions of NP (Net Processor) are required to provide the MP with the necessary resources to complete the molecular operation of the service.

The AG service is divided into a Broadband service and a Narrow band service, and the types of system resources required for these two types of services are also different. For example, broadband requires large data processing and storage, while narrowband requires high real-time performance of the system. At the same time, this data requires high reliability. Therefore, the concept of master-slave needs to be introduced. The same MP is equipped with 2 blocks, the same NP is equipped with two blocks, two MPs are used for active and standby, and two NPs are used for active and standby. The primary device is responsible for allocating resource selection control logic. If there is an abnormality in the board of the active device, the primary state is abandoned and the switchover is standby, and the original standby automatically rises to the primary use, taking over the control logic and data processing of the primary use to ensure the correctness of service data and resource usage. Ensure the normal operation of business applications and improve system stability in extreme cases. However, the inventors have found that the relationship of 1:1 between the primary and secondary devices in the related art is not stable enough, and an effective solution has not been proposed for the problem of instability in the related art. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a method and apparatus for switching between primary and backup devices based on an access gateway to solve at least the above problems. According to an aspect of the present invention, a primary backup device switching method based on an access gateway is provided, which includes: configuring N standby devices for a primary device carrying a service, where N≥l; When an abnormality occurs in the device, an available backup device is selected from the N standby devices; and the selected backup device is used to replace the primary device to carry the service. The step of configuring N standby devices for one primary device carrying the service includes: setting the primary device as a unit state, and setting each of the standby devices as a port state; in one of the above unit states and N above A mapping relationship is established between port states. The step of selecting an available spare device from the above N standby devices includes: selecting the above-mentioned available spare devices with the highest priority from among the N standby devices. Before selecting the above-mentioned available backup device with the highest priority from the foregoing N backup devices, the method further includes: configuring the priority of the N standby devices according to the sequence reported to the line card, where the priority of the foregoing standby device is reported first The level is higher than the priority of the above-mentioned standby device reported later. When the selected backup device is used to replace the foregoing primary device to carry the service, the method further includes: setting the primary device as a backup device, and setting a priority corresponding to the backup device to a lowest level priority. Determining whether the primary device is abnormal by one of the following steps: if the primary device is migrated from the available state to the unavailable state, it is determined that the primary device is abnormal; if the primary monitoring device is in the switching monitoring resource If the one or more resources are abnormal, it is determined that the primary device is abnormal; or if the switching command sent by the user is received, it is determined that the primary device is abnormal. The step of using the selected backup device to replace the foregoing primary device to carry the service includes: determining whether the active/standby switchover flag corresponding to the active/standby switchover is true; if true, the active/standby switchover is not completed, and the receiving is not completed. The received heartbeat signal is processed; if not, it indicates that the above-mentioned active/standby switchover has been completed, and the received heartbeat signal is processed. According to another aspect of the present invention, an access gateway-based primary backup device switching apparatus is provided, including: a configuration unit configured to configure N standby devices for one primary device carrying a service, where N≥ l; selecting a unit, configured to select an available spare device from the N standby devices when the primary device is abnormal; the switching unit is configured to use the selected backup device instead of the primary device to carry the above business. The configuration unit includes: a configuration module, configured to set the primary device to a unit state, and set each of the standby devices to a port state; and the mapping module is configured to be in one of the foregoing unit states and N of the foregoing port states Establish a mapping relationship. The selecting unit includes: a selecting module, configured to select the available spare device with the highest priority from the N standby devices. The configuration unit is further configured to: prior to selecting the available spare device with the highest priority among the N standby devices, configure the priority of the N standby devices according to the sequence reported to the line card, where the foregoing standby is reported first. The priority of the device is higher than the priority of the above-mentioned standby device reported later. In the present invention, the traditional dual-device mutual active and standby devices are expanded, and the primary device and the corresponding multiple standby devices are used to securely manage the device, thereby solving the related technologies in the primary and secondary devices: The relationship between 1 is not stable enough. When the system is abnormal, the system resources and business application switching can be smoothly transitioned. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 is a preferred flowchart of a method for switching a primary backup device based on an access gateway according to an embodiment of the present invention; FIG. 2 is a schematic diagram of a primary backup device switching device based on an access gateway according to an embodiment of the present invention; FIG. 3 is a flowchart of an NP booting active/standby allocation according to an embodiment of the present invention; FIG. 4 is a flowchart of initiating a switching after a primary NP device is abnormal according to an embodiment of the present invention; A flowchart of initiating switching of an active NP resource exception according to an embodiment of the present invention; FIG. 6 is a flowchart of command initiation switching according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS Embodiment 1 FIG. 1 is a preferred flowchart of a method for switching a primary backup device based on an access gateway according to an embodiment of the present invention, which includes: S102. Configure N standby devices for the primary device that carries the service, where N≥l

S104. When an abnormality occurs in the primary device, select one available backup device from the N standby devices.

S106, using the selected backup device to replace the primary device to carry the service. In the preferred embodiment, the traditional dual-device mutual active and standby devices are expanded, and the primary device and the corresponding multiple backup devices are used to securely manage the device, thereby solving the related technologies in the active and standby devices. The problem that the relationship between 1: 1 is not stable enough, when the system is abnormal, the system resources and business applications switch smoothly. Preferably, the step of configuring N standby devices for one primary device carrying services includes: setting the primary devices to a unit state, and setting each of the standby devices to a port state. Establishing a mapping relationship between one of the Unit states and N of the Port states. In the preferred embodiment, the switching can be effectively performed by such a mapping relationship. Preferably, the step of selecting one available backup device from the N standby devices may include, but is not limited to: selecting the available backup device with the highest priority from the N backup devices. Of course, the present invention can also select another available backup device from the N spare devices by using other strategies. Preferably, the access gateway-based primary standby switching method according to the embodiment of the present invention further includes: following the sequence reported to the line card, before the selecting the available backup device with the highest priority from the N backup devices The priority of the N standby devices is configured, where the priority of the standby device that is reported first is higher than the priority of the standby device that is reported later. In the preferred embodiment, the priorities are configured in the reported order, and a valid spare device can be better selected to replace the primary device. Preferably, when the selected backup device is used to replace the primary device to carry the service, the access gateway-based primary backup device switching method according to the embodiment of the present invention further includes: setting the primary device as The standby device, and the priority corresponding to the standby device is set to the lowest priority. In the preferred embodiment, the primary device that is currently abnormal is set as the standby device with the lowest priority. Such a mechanism enables the backup device that replaces the primary device to better meet the requirements of the current system after the next handover. Preferably, it is determined whether the primary device is abnormal by one of the following steps: if the primary device is migrated from an available state to an unavailable state, determining that the primary device is abnormal; if the primary device is If the one or more resources in the switching monitoring resource are abnormal, it is determined that the primary device is abnormal; or if the switching command sent by the user is received, it is determined that the primary device is abnormal. In the preferred embodiment, a variety of determinations are provided to enable the present invention to be applied to a variety of scenarios. Preferably, the step of using the selected backup device to replace the primary device to carry the service includes: determining whether the active/standby switch flag corresponding to the active/standby switchover is true; if true, indicating that the active/standby switch is active If the switchover is not completed, the received heartbeat signal is not processed; if not, it indicates that the master/slave switchover is completed, and the received heartbeat signal is processed. In the preferred embodiment, the active/standby switchover is used to determine whether the active/standby switchover is complete, thereby performing different operations on the heartbeat signal, thereby improving the stability of the active/standby switchover. Embodiment 2 FIG. 2 is a schematic structural diagram of an access gateway-based primary backup device switching apparatus according to an embodiment of the present invention, which includes: a configuration unit 202 configured to configure N primary devices for one bearer service a backup device, wherein: N≥1; the selecting unit 204 is connected to the configuration unit 202, and is configured to select an available standby device from the N standby devices when the primary device is abnormal; the switching unit 206, Connected to the selection unit 204, arranged to use the selected spare device in place of the primary device to carry the service. In the preferred embodiment, the traditional dual-device mutual active and standby devices are expanded, and the primary device and the corresponding multiple backup devices are used to securely manage the device, thereby solving the related technologies in the active and standby devices. The problem that the relationship between 1: 1 is not stable enough, when the system is abnormal, the system resources and business applications switch smoothly. Preferably, the configuration unit 202 includes: a configuration module, configured to set the primary device to a unit state, and set each of the standby devices to a port state; and a mapping module, configured to be in the one of the units A mapping relationship is established between the state and the N port states. In the preferred embodiment, the switching can be effectively performed by such a mapping relationship. Preferably, the selecting unit 204 includes: a selecting module, configured to select the available standby device with the highest priority from the N standby devices. Of course, the selection unit in the preferred embodiment may also select another available backup device from the N spare devices by using other policies. Preferably, the configuration unit 202 is further configured to configure the priority of the backup devices according to the sequence reported to the line card before selecting the available backup devices with the highest priority from the one of the backup devices. The priority of the standby device that is reported first is higher than the priority of the standby device that is reported later. In the preferred embodiment, the priorities are configured in the reported order, and a valid spare device can be better selected to replace the primary device. Preferably, when the selected backup device is used to replace the primary device to carry the service, the configuration unit 202 sets the primary device as a backup device, and sets a priority corresponding to the backup device to a lowest level. Priority. In the preferred embodiment, the primary device that is currently abnormal is set as the standby device with the lowest priority. Such a mechanism enables the backup device that replaces the primary device to better meet the requirements of the current system after the next handover. Preferably, the access gateway-based primary standby switching device according to the embodiment of the present invention determines whether the primary device is abnormal by one of the following steps: if the primary device migrates from an available state to an unavailable state, Determining that the primary device is abnormal; if one or more of the resources of the switching monitoring resource on the primary device are abnormal, determining that the primary device is abnormal; or receiving the user The sent switching command determines that the primary device is abnormal. In the preferred embodiment, a variety of determinations are provided to enable the present invention to be applied to a variety of scenarios. Preferably, the step of using the selected backup device to replace the primary device to carry the service includes: determining whether the active/standby switch flag corresponding to the active/standby switchover is true; if true, indicating The active/standby switchover is not completed, and the received heartbeat signal is not processed; if not, it indicates that the active/standby switchover is completed, and the received heartbeat signal is processed. In the preferred embodiment, the active/standby switchover is used to determine whether the active/standby switchover is complete, thereby performing different operations on the heartbeat signal, thereby improving the stability of the active/standby switchover. Embodiment 3 This embodiment provides an update alternative for hardware active and standby management. After the hardware design is completed, you can optionally increase the primary and secondary exception detection conditions without replacing or modifying the hardware. In addition, on the basis of the above, the original 4 original concepts of the main and the standby are expanded, and the active and standby devices are expanded from 1:1 (one main use and one standby) to 1: (- main use multiple standby), which enhances the system. Robustness makes the system more stable. In this embodiment, 1: Ν device management can allow multiple backup devices, and the backup devices are managed in a priority manner. When the primary device is abnormal, the highest priority available device in the standby device is used as the primary device. The priority of the remaining standby devices is increased in turn, the original primary usage is reduced to standby, and the standby device priority chain is inserted in the footer, and the priority is reduced to the lowest. In this embodiment, 1: N device management can implement logical data of Unit and Port: Unit (control unit); Port port resource, which is a sub-resource to which the unit belongs, is used to identify each device. If separate device states are used to indicate the active and standby states respectively, each service application and system application needs to query each device, which is too complicated and inefficient, so the control of Unit + Port is introduced when managing the standby device. Logic, abstracting the devices that are mutually active and standby into one unit, Unit indicates the total status of the devices as the master and standby devices, and the port status indicates the active and standby status of each device. This facilitates the application and implements 1: N (1 master) With the management of multiple standby devices, you can directly manage devices that are active and standby, enabling the service to easily implement data synchronization, traffic load balancing, and abnormal traffic switching. For the NP (net processor) class device 1 in the AG: N, the active and standby data management uses Unit,

Port manages the device. The corresponding relationship is that one unit corresponds to N ports, and each port corresponds to one NP device, and multiple NP devices belong to one unit. The corresponding Unit and Port of each device are dynamically allocated on the (MP) main control board. The initial value is assigned to 1. The configured NP device dynamically allocates unoccupied Unit and Port resources, and then the main port of the port. The standby attributes are associated to be subordinate to the dynamically allocated Unit. After the line card is deleted, the active and standby ports and the association information with the unit are cleared, so that the Unit and Port resources are in the state of being dynamically allocated. The priority of the standby device is recorded in the Unit data. The priority can be configured and adjusted through commands. The initial priority is assigned in the order of 4艮 on the line card. The priority of the standby device is assigned to the high priority. The priority of the last 4 递 is decremented. When the primary device exception occurs, the standby device upgrade policy is to use the highest priority available standby device. When the standby device is abnormal, the priority of the standby device in the Unit data and the Port data is updated, the device priority list after the abnormal device node is moved forward, and the abnormal device is inserted into the link header, and the priority is reduced to the lowest.

The NP line card side's own data management is managed by the Port method. This configuration is responsible for maintaining the configuration delivered by the MP main control board, including the active status, standby status, service status, and offline status. The master/slave switching method provided in this embodiment is as follows: After the NP is started, the initial port state is set to the MP, and then the MP determines the primary standby state of the NP according to the preemptive manner, that is, the port state of the NP is first reported to be the primary port. When the NP of the primary NP is abnormal (the abnormality at this time can be defined by the relevant application), the NP notifies the MP of the abnormal cause, and the MP determines that the standby can be switched. The MP initiates the master/slave state switchover, reassigns the configuration to the NP in the active/standby state, and switches the original primary service resource to the standby device to enable the service to run normally. The following describes the specific implementation method of the 1:N device, which is divided into the following steps:

(1) At the time of NP startup: As shown in Figure 3, the initial port state of the NP is given to the MP, and then the MP allocates the active/standby state of the NP device according to the dynamically assigned control logic. Preferably, the NP that reports the port state is allocated as the first in state of port is master, and the MP sends the primary data to the primary NP, and notifies the NP to update its state for the primary use, and then The primary NP starts to report the heartbeat for the MP to monitor; the NP of the last 4 艮 Port state is assigned as the second in state of port is slave, and the MP sends the standby data to the standby NP, notifying the The NP updates its own state to standby. Then, the standby NP starts to report the heartbeat (including the port primary standby status information) for monitoring by the MP.

(2) The MP monitoring module finds that when the NP Port status is migrated:

The MP checks the NP Port state migration process. If the standby device is migrated from the available state to the unavailable state, it only informs the service that the device is not available now, and the resource needs to be reselected from the active device. If the active device is migrated from the available state to the unavailable state, and the standby device is available at this time, the MP initiates the switching of the NP device, changes the primary standby state information of the NP Port data recorded on the MP, and sets the port state of the active device. Set to be unavailable, set the port status of the standby device as the primary, re-issue the configuration to the NP, notify it to switch and update the port status change on the NP for the primary use, and the NP immediately sends the 4th heart to the MP, and the MP receives Then, as a response to the successful switchover, the new active device is monitored. If the switchover success response is not received (the heartbeat port status reported by the NP is always standby), the configuration is sent until the switchover is successful. The heartbeat Port status is mainly used). After the switchover is successful, all resources are switched to the new active device to ensure the normal operation of the running service and the new service. (3) When the resources on the NP are abnormal: As shown in Figure 5, the switching monitoring resources on the NP can be registered. After registration, the primary NP detection module is responsible for scanning whether the registered resources are normal, if one or more of these resources (Any case when all kinds of resources are abnormal) When an abnormality occurs, the active NP initiates a switching notification to notify the MP to perform switching (S501). After receiving the notification, the MP sets the switching timer. Preferably, the timer timeout period is tentatively set to 5 seconds (the timeout period can be adjusted according to different hardware of the device), and the reason for the port switching and the switching flag are set, wherein the switching flag is used for The heartbeat is blocked (S502). Preferably, when the heartbeat of the NP of the unit is processed, it is determined whether the switching flag used for the port switching is true. If true, the processing is not processed, so as to prevent the NP port processing from being disordered when the switching is not completed. . Then, the MP queries the standby NP for the standby switching condition (S503), and the standby NP sends the query result to the MP, for example, informing the MP standby NP that the switching condition is met (S504). After the standby NP meets the switching condition, the MP sends a configuration message to the standby NP to notify the NP switchover (S505). If the switchover succeeds, the timer and the switch flag are cancelled (S506), and then the standby NP reports the heartbeat (Port is mainly used) i MP (S507), 4 艮 heartbeat (Port is standby) i MP (S508) on the primary NP. If the switch fails (for example, the above-mentioned set switch timer expires, or the standby NP device is also unavailable or the resource is abnormal. Status), the MP re-distributes the configuration to the primary NP and the standby NP, so as to restore to the port state before the switching (S509), and then, the primary NP has 4 艮 heartbeat (Port is mainly used) to the MP (S510), After the switchover detection timer is set, set the port active/standby state corresponding to the NP on the standby NP, and then reconfigure the new active/standby state. To NP, the NP is notified to update its own port status, and the heartbeat is reported to the MP as a response, and the MP starts monitoring the port status of the NP.

(4) Command-initiated switching: As shown in Figure 6, this switching is manually initiated by the user (S601). After receiving the user command, the MP sets the switching timer. Preferably, the timer expires for 5 seconds. (The timeout period can be adjusted according to different hardware of the device), and the reason for the port switching and the switching flag are set, wherein the switching flag is used to block the heartbeat (S602). Preferably, when the heartbeat of the NP of the unit is processed, it is determined whether the switching flag used for the port switching is true. If true, the processing is not processed, so as to prevent the NP port processing from being disordered when the switching is not completed. . Then, the MP queries the standby NP for the standby switching condition (S603), and the standby NP sends the query result to the MP, for example, informing the MP standby NP that the switching condition is met (S604). After the standby NP meets the switching condition, the MP sends a configuration message to the standby NP to notify the NP switchover (S605). If the switchover succeeds, the timer and the switch flag are cancelled (S606), and then the standby NP reports the heartbeat (Port is mainly used). ) to MP (S607), the main NP is 4 艮 heartbeat (Port is standby) to MP (S608) „ If the switchover fails (for example, if the switchover timer is set to expire or the standby NP device is unavailable or the resource is abnormal), the MP re-delivers the configuration to the active NP and the standby NP to restore the port state before the switchover. (S609), then, the primary NP is 4 艮 heartbeat (Port is used for) to MP (S610), and the standby NP is 4 艮 (Port is standby) to MP (S610). (5) Handling of abnormal conditions: When the NP device is dual-active or dual-standby, the monitoring module corresponding to the NP Port on the MP determines the primary standby state of the port in the heartbeat message reported by the NP, if a dual-active or dual-standby conflict occurs. The configuration data is re-configured to change the active/standby status of the port currently reported to the NP device to prevent abnormalities on the service. The preferred embodiment has the following beneficial effects: The expansion of the management of the active and standby devices can be implemented on the basis of the standard equipment, and a convenient and practical solution is invented for the management functions of the primary and secondary devices. In a system with the same high stability and stability in the system, you only need to configure the active/standby mode to ensure the stability of the system while balancing the traffic and data traffic. A typical example of the main board management of the AG board 1:N is described below with reference to the accompanying drawings. As shown in FIG. 3-6, the active/standby management mechanism according to the preferred embodiment of the present invention includes:

1) As shown in Figure 3, in the initial state of the NP, the PortState structure is given to the MP. The MP receives the PortState message on the NP, updates the Port state recorded in the UnitState, and assigns the active and standby states of the NP.

2) After receiving the configuration message sent by the MP device, the NP device configures the NpPortState structure and then reports it. For the process, refer to Figure 3.

3) The MP side periodically monitors whether the NP device is working normally. For the specific process, refer to FIG. 4 . As shown in FIG. 4, the MP side sets a 2-second NP device Port state detection cycle timer TIMER4 to poll all NP devices. If the primary NP does not report the heartbeat or reports that the port status is abnormal (for example, the heartbeat message is not received within 10 seconds), the primary NP is processed offline. If there is a standby NP, the MP queries the standby NP for the standby switching condition, and the standby NP ^! The result of the query is sent to the MP to inform the MP that the standby NP meets the switching condition. Under the alternate NP-compliant switching condition, the MP sends a configuration message to the current primary NP and the standby NP to notify the NP switch. 4) The important resources registered by the software are regularly monitored. When the resources are abnormal or unavailable, the switching process is initiated. For the specific process, reference may be made to FIG. 5 and the description of FIG. 5 above. In the preferred embodiment, the NP notifies the MP to attempt to switch by sending an NP ChangeOver message. After receiving the message, the MP checks whether the standby device in the UnitState structure is available, and then performs the ascending operation. 5) Exception handling:

1. The NP initiates a switchover, sets the switchover timer, and periodically checks whether the switchover is successful. If the switchover fails, the NP PortState state before the switchover is restored.

2. There are multiple active and non-active situations. When the device is already active, the Ppmgt_checkreceive_proc( ) function detects whether there is an active device in the standby device list in the UnitState structure. If there is a notification, the device is downgraded to standby. For the specific process, see Figures 5 and 6. When UnitState [Unitno]. state == Unit_Stb_Used, the Ppmgt_checkreceive_proc ( ) function selects the highest priority of the alternate device list. Through the above steps, the AG NP 1: N active/standby management is implemented, and the solution is simple and reliable. It fills the gap in the communication field for equipment reliability and stability, and the 1:N active/standby management mode. The present invention is applicable to devices requiring high stability, high reliability, and high efficiency in systems such as AG (Access Gateway Integrated Access Gateway), PON (Passive Optical Networks, Passive Optical Networks, including EPON, GPON, NG-PON) . Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the scope of the present invention are intended to be included within the scope of the present invention.

Claims

A method for switching between primary and backup devices based on an access gateway, including:

Configuring N standby devices for the primary device that carries the service, where N > 2, when the primary device is abnormal, select one available backup device from the N standby devices;

The selected backup device is used instead of the primary device to carry the service. The method according to claim 1, wherein the step of configuring N standby devices for one primary device carrying the service includes:

Setting the primary device to a unit state, and setting each of the standby devices to a port state;

A mapping relationship is established between one of the unit states and N of the port states. The method according to claim 1, wherein the step of selecting an available spare device from the N spare devices comprises:

Selecting the available backup device with the highest priority from the N spare devices. The method according to claim 3, wherein before selecting the available backup device with the highest priority from the N standby devices, the method further includes:

The priority of the N standby devices is configured according to the sequence reported to the line card, wherein the priority of the standby device that is reported first is higher than the priority of the standby device that is reported later. The method according to claim 4, wherein when the selected backup device is used instead of the active device to carry the service, the method further includes:

The primary device is set as a standby device, and the priority corresponding to the standby device is set to the lowest priority. The method according to claim 1, wherein the abnormality of the main device is determined by one of the following steps:

If the active device is migrated from an available state to an unavailable state, determining that the primary device is abnormal; If an abnormality occurs in one or more resources of the switching monitoring resource on the active device, determining that the primary device is abnormal; or

If the switching command sent by the user is received, it is determined that the primary device is abnormal.

7. The method according to claim 1, wherein the step of using the selected backup device to replace the primary device to carry the service comprises:

Determine whether the active/standby switch flag corresponding to the active/standby switchover is true.

If true, the active/standby switchover is not completed, and the received heartbeat signal is not processed.

If not, it indicates that the active/standby switchover has been completed, and the received heartbeat signal is processed.

8. The primary and secondary device switching device based on the access gateway, comprising:

The configuration unit is configured to configure N standby devices for one primary device carrying the service, where N > 2

Selecting a unit, configured to select an available spare device from the N spare devices when an abnormality occurs in the primary device;

A switching unit is arranged to use the selected spare device in place of the primary device to carry the service.

9. The device according to claim 8, wherein the configuration unit comprises:

a configuration module, configured to set the primary device to a unit state, and set each of the standby devices to a port state;

The mapping module is configured to establish a mapping relationship between one of the unit states and N of the port states.

10. The apparatus according to claim 8, wherein the selecting unit comprises:

The selection module is configured to select the available backup device with the highest priority from the N spare devices.

The device according to claim 10, wherein the configuration unit is further configured to report to the available backup device with the highest priority from the N backup devices, according to reporting The priority of the N backup devices is configured in the order of the line cards, wherein the priority of the standby device that is reported first is higher than the priority of the standby device that is reported later.