Communication recovery method for link fault and related device

Abstract

The invention discloses a communication recovery method for a link fault, which is applied to network equipment in a wireless mesh network. In the method, a network device in the wireless mesh network detects a link state with a neighbor device, and reports the link state of the network device and the neighbor device to a specified device of the wireless mesh network, so that the specified device can carry out communication according to the link state between the network devices in the whole wireless mesh network. And issuing a main path and a standby path for guiding the network equipment to transmit data to each network equipment. Therefore, the network equipment in the wireless mesh network can adopt the main path to transmit data in the working process, and can be quickly switched to the standby path issued in advance when the link of the main path fails, so that the condition of service interruption is avoided, and the normal operation of the service can be ensured when the link between the network equipment is changed.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a communication recovery method and related devices for link failure. Background Art

[0002] A wireless mesh network is a multi-hop wireless network. The biggest difference between it and a traditional single-hop wireless network is that it uses wireless links instead of wired links to connect multiple access points (APs). The APs in a wireless mesh network not only provide user access functions, but also forward data on wireless links, so that data is routed from one AP to another, and finally accesses the wired network through a portal node, thus forming a wireless mesh network.

[0003] Wireless mesh networks eliminate the need for wiring between APs, making installation and deployment more flexible. In a wireless mesh network, if you want to add a new node device, you only need to simply connect the power supply to automatically configure it and determine the best multi-hop transmission path. Compared with traditional wireless local area networks (WLANs), wireless mesh networks can significantly reduce deployment costs and provide greater convenience and scalability. Therefore, in addition to being used in common scenarios of traditional WLANs such as enterprise networks, office networks, and campus networks, wireless mesh networks are also widely used in large warehouses, port terminals, mine tunnels, emergency communications, and other scenarios where wiring is inconvenient or costly.

[0004] However, the current wireless mesh network standards mainly focus on solving the network connectivity problem when using wireless connections between APs, and do not pay attention to the situation where the wireless links between APs may move during use, causing drastic changes in the wireless channels. As a result, in some scenarios, wireless mesh networks may experience data packet loss or even service interruption, affecting the normal operation of the business. Summary of the invention

[0005] The present application provides a communication recovery method for link failure, which can quickly restore communication when a link failure occurs, thereby ensuring the normal operation of the business.

[0006] The first aspect of the present application provides a communication recovery method for link failure, which is applied to a first network device in a wireless mesh network. The method includes: first, the first network device measures the link status between the first network device and a neighboring device. The first network device is any device other than a root node device in a tree topology constructed based on the wireless mesh network, such as a physical device such as a router, a wireless switch or a wireless transceiver.

[0007] After measuring the link status, the first network device sends the first link information to the second network device, and the first link information is used to indicate the link status between the first network device and the neighboring device. Specifically, the first link information is actually used to indicate the link status between the first network device and each neighboring device in multiple neighboring devices, such as the link status between the first network device and the first neighboring device, and the link status between the first network device and the second neighboring device. The second network device is a designated device in the wireless mesh network, which is used to receive the link information reported by other network devices in the wireless mesh network, and then send the corresponding main path and backup path to each network device based on the acquired link information.

[0008] Secondly, the first network device receives a main path and a backup path from the second network device, both of which are used to indicate the path of the first network device to forward data, the main path includes a link between the first network device and the first neighbor device, and the backup path includes a link between the first network device and the second neighbor device. The first neighbor device and the second neighbor device are both neighbor devices of the first network device, and can assist in forwarding data sent by the first network device.

[0009] Finally, when a link in the primary path fails, the first network device forwards data through the backup path.

[0010] In this solution, the network device in the wireless mesh network first detects the link status between the device and the neighboring device, and reports the link status between the device and the neighboring device to the designated device of the wireless mesh network, so that the designated device can issue the main path and backup path to guide the network device to transmit data to each other network device according to the link status between the network devices in the entire wireless mesh network. In this way, the network devices in the wireless mesh network can use the main path to transmit data during the working process, and when the link of the main path fails, it can quickly switch to the backup path issued in advance to avoid business interruption and ensure that the business can be carried out normally when the link between network devices fails.

[0011] In a possible implementation manner, the first network device sends the first link information to the second network device, specifically including: the first network device sends a first broadcast message, where the first broadcast message includes the first link information.

[0012] In a possible implementation, the second network device is a root node device in a tree topology constructed based on a wireless mesh network. For example, the second network device is a boundary device between an external network and a wireless mesh network, and is responsible for providing a function of accessing an external network for network devices in the wireless mesh network. In the case where the first network device has a child node device, the first network device can receive second link information sent by the child node device, and the second link information is used to indicate the link status between the child node device and a neighboring device of the child node device; the first network device forwards the second link information to the second network device.

[0013] In this solution, when the first network device has a sub-node device, the data transmission characteristics of the wireless mesh network are utilized, and the first network device assists the sub-node device in forwarding the link information from the sub-node device to the root node device, thereby ensuring that the link information measured by all network devices in the wireless mesh network can be effectively reported to the root node device.

[0014] In a possible implementation, the first network device sends the first link information to the second network device, including: the first network device sends the second broadcast message to the second network device, and the second broadcast message includes the first link information and the second link information. That is, the first network device carries the link information measured by itself and the link information measured by the sub-node device at the same time through a broadcast message, thereby reducing message overhead and improving the transmission efficiency of the link information.

[0015] In a possible implementation manner, the first broadcast message includes a first beacon frame, and the first link information is carried in an extension field or a vendor specific field in the first Beacon frame.

[0016] In this solution, by carrying the link information measured by the network device in the existing broadcast message of the wireless mesh network, it is possible to report the link status to the root node device, reduce the changes to the existing technology, and improve the feasibility of this solution.

[0017] In a possible implementation, the first network device may directly send a first unicast message to the second network device, where the first unicast message includes the first link information, and the destination address of the first unicast message is the address of the second network device.

[0018] In this solution, by sending a unicast message from the first network device to the root node device, it is possible to transmit link information to the root node device in a directional manner, thereby ensuring that the root node device accurately receives the link information from the first network device.

[0019] In a possible implementation manner, the first unicast message includes an extended management frame, and the first link information is carried in the extended management frame;

[0020] Alternatively, the first unicast message includes a path request PREQ frame, and the first link information is carried in the PREQ frame.

[0021] In this solution, link information is carried on the basis of existing data frames, and link status can be reported to the root node device, which reduces changes to existing technologies and improves the feasibility of this solution.

[0022] In a possible implementation, the first network device periodically sends the first link information to the second network device. For example, the first network device periodically reports the first link information measured by the device to the second network device through a broadcast message.

[0023] Alternatively, the first network device sends the first link information to the second network device when the link status between the first network device and the neighboring device changes.

[0024] In general, using broadcast messages to report link status is suitable for the slave node (i.e., the first network device) to periodically report neighbor link status; using unicast messages to report link status is suitable for the slave node to report neighbor link status after an event is triggered. The combination of the two different reporting methods enables the master node to grasp the link quality of each node in the entire network in real time.

[0025] In a possible implementation manner, the first link information includes an identifier of the first network device, the number of neighbor devices, identifiers of the neighbor devices, and link quality metrics between the first network device and the neighbor devices.

[0026] In a possible implementation manner, the first network device receives the primary path and the backup path from the second network device, including: the first network device receives a third broadcast message, and the third broadcast message includes the primary path and the backup path of the first network device.

[0027] In one possible implementation, the second network device is a root node device in a tree topology constructed based on a wireless mesh network. When the first network device has a child node device, the third broadcast message also includes a main path and a backup path of the child node device of the first network device; the first network device sends a fourth broadcast message, and the fourth broadcast message includes the main path and the backup path of the child node device of the first network device.

[0028] In this solution, after receiving a broadcast message as a parent node device, the path information related to the device is obtained from the broadcast message, and a new broadcast message is generated based on the path information related to the child node device of the device in the broadcast message, and then the new broadcast message is continued to be sent to ensure that the child node device can obtain the path information based on the new broadcast message. Since the path information related to the parent node device is removed from the new broadcast message, the sending overhead of the broadcast message can be reduced as much as possible.

[0029] In a possible implementation, the third broadcast message includes a second Beacon frame, and the primary path and the backup path are carried in an extended field or a Vendor Specific field in the second Beacon frame.

[0030] In a possible implementation manner, a first network device receives a second unicast message from a second network device, where the second unicast message includes a primary path and a backup path of the first network device.

[0031] In a possible implementation manner, the primary path and the backup path include at least one of the following: path priority, path hop count, and identification of a network device that the path passes through.

[0032] In a possible implementation, after a link failure in the primary path occurs, the first network device may further send a routing reset message to the second network device through the backup path, where the routing reset message is used to indicate the link failure in the primary path.

[0033] That is to say, the routing reset message is equivalent to notifying the second network device that the main path used on the first network device has failed, so the second network device can plan a new path for the first network device, so that the second network device can subsequently issue a more suitable new path to the first network device.

[0034] The second aspect of the present application provides a communication recovery method for link failure, which is applied to a second network device in a wireless mesh network, and the method includes: first, the second network device receives multiple link information, the multiple link information comes from multiple network devices in the wireless mesh network, and the multiple link information is used to indicate the link status between different network devices and neighboring devices. Since each network device except the second network device in the wireless mesh network will perform a process of measuring the link status between the neighboring device and send link information indicating the link status between itself and the neighboring device to the second network device, the second network device can receive multiple link information. In addition, the multiple link information received by the second network device comes from different network devices in the wireless mesh network, and each link information is used to indicate the link status between the network device that generates the link information and the neighboring device.

[0035] Then, the second network device determines a main path and a backup path of the first network device based on multiple link information, wherein the multiple network devices include the first network device, the main path and the backup path are both used to indicate the path along which the first network device forwards data, the main path includes a link between the first network device and a first neighboring device, and the backup path includes a link between the first network device and a second neighboring device.

[0036] Secondly, the second network device sends the primary path and the backup path to the first network device, where the backup path is used to be enabled when a link in the primary path fails.

[0037] In a possible implementation, the second network device receives multiple link information, including: the second network device receives a first broadcast message from the first network device, the first broadcast message includes first link information, and the first link information is used to indicate the link status between the first network device and a neighboring device. In the case where the first network device has a child node device, the first link information is also used to indicate the link information between the child node device of the first network device and the neighboring device.

[0038] In a possible implementation manner, the first broadcast message includes a Beacon frame, and the first link information is carried in an extension field or a Vendor Specific field in the Beacon frame.

[0039] In a possible implementation, the second network device receives multiple link information, including: the second network device receives a first unicast message sent by the first network device, the first unicast message includes first link information, and the first link information is used to indicate the link status between the first network device and a neighboring device.

[0040] In a possible implementation manner, the first unicast message includes an extended management frame, and the first link information is carried in the extended management frame;

[0041] Alternatively, the first unicast message includes a PREP frame, and the first link information is carried in the PREP frame.

[0042] In a possible implementation manner, the second network device sends the primary path and the backup path to the first network device, including:

[0043] The second network device sends a second broadcast message, where the second broadcast message includes a primary path and a backup path;

[0044] Alternatively, the second network device sends a second unicast message, where the second unicast message includes the primary path and the backup path.

[0045] In a possible implementation manner, the second broadcast message includes a second beacon frame, and the primary path and the backup path are carried in an extended field or a Vendor Specific field in the second Beacon frame.

[0046] In a possible implementation, the second unicast message includes an extended management frame, and the primary path and the backup path are carried in the extended management frame;

[0047] Alternatively, the second unicast message includes a PREP frame, and the primary path and the backup path are carried in the PREP frame.

[0048] In a possible implementation manner, the first link information includes an identifier of the first network device, the number of neighbor devices, identifiers of the neighbor devices, and link quality metrics between the first network device and the neighbor devices.

[0049] In a possible implementation manner, the primary path and the backup path include at least one of the following: path priority, path hop count, and identification of a network device that the path passes through.

[0050] In a possible implementation, the second network device sends the primary path and the backup path to the first network device, including: the second network device sends a routing broadcast message, where the routing broadcast message includes the primary path and the backup path of each network device in the plurality of network devices.

[0051] In a possible implementation, the method also includes: the second network device receives a routing reset message from the first network device, the routing reset message is used to indicate a link failure in the primary path; the second network device determines a new primary path and a new backup path corresponding to the first network device based on the routing reset message; and the second network device sends the new primary path and the new backup path to the first network device.

[0052] A third aspect of the present application provides a network device, the network device being a device in a wireless mesh network, the network device comprising:

[0053] A sending module, used to send first link information to the second network device, where the first link information of the wireless mesh network is used to indicate the link status between the first network device and a plurality of neighboring devices;

[0054] A receiving module, used to receive a primary path and a backup path from a second network device, where both the primary path and the backup path are used to indicate a path for the first network device to forward data, where the primary path includes a link between the first network device and a first neighboring device, and where the backup path includes a link between the first network device and a second neighboring device;

[0055] The sending module is also used to forward data through a backup path when a link in the primary path fails.

[0056] In a possible implementation, the sending module is further configured to send a first broadcast message, where the first broadcast message includes the first link information.

[0057] In one possible implementation, the second network device is a root node device in a tree topology constructed based on a wireless mesh network. When the first network device has a child node device, the receiving module is also used to receive second link information sent by the child node device, and the second link information is used to indicate the link status between the child node device and a neighbor device of the child node device; the sending module is also used to forward the second link information to the second network device.

[0058] In a possible implementation, the sending module is further configured to send a second broadcast message to the user, where the second broadcast message includes the first link information and the second link information.

[0059] In a possible implementation manner, the first broadcast message includes a Beacon frame, and the first link information is carried in an extension field or a Vendor Specific field in the Beacon frame.

[0060] In a possible implementation, the sending module is further configured to send a first unicast message to the second network device, where the first unicast message includes the first link information.

[0061] In a possible implementation manner, the first unicast message includes an extended management frame, and the first link information is carried in the extended management frame;

[0062] Alternatively, the first unicast message includes a PREQ frame, and the first link information is carried in the PREQ frame.

[0063] In a possible implementation manner, the first link information includes an identifier of the first network device, the number of neighbor devices, identifiers of the neighbor devices, and link quality metrics between the first network device and the neighbor devices.

[0064] In a possible implementation, the first network device periodically sends the first link information to the second network device. For example, the first network device periodically reports the first link information measured by the device to the second network device through a broadcast message.

[0065] Alternatively, the first network device sends the first link information to the second network device when the link status between the first network device and the neighboring device changes.

[0066] In a possible implementation manner, the network device further includes:

[0067] A measurement module is used to measure the link status between the plurality of neighbor devices and generate the first link information based on the measured link status.

[0068] In a possible implementation, the receiving module is further configured to receive a third broadcast message, where the third broadcast message includes a primary path and a backup path of the first network device.

[0069] In a possible implementation, the third broadcast message also includes the main path and the backup path of the sub-node device of the first network device; the sending module is also used to send a fourth broadcast message, and the fourth broadcast message includes the main path and the backup path of the sub-node device of the first network device.

[0070] In a possible implementation, the second network device is a root node device in a tree topology constructed based on a wireless mesh network, and when the first network device has a child node device, the third broadcast message also includes a primary path and a backup path of the child node device of the first network device;

[0071] The sending module is further used to send a fourth broadcast message, where the fourth broadcast message includes a primary path and a backup path of the sub-node device of the first network device.

[0072] In a possible implementation, the third broadcast message includes a second Beacon frame, and the primary path and the backup path are carried in an extended field or a Vendor Specific field in the second Beacon frame.

[0073] In a possible implementation, the receiving module is further configured to receive a second unicast message, where the second unicast message includes a primary path and a backup path of the first network device.

[0074] In a possible implementation, the second unicast message includes an extended management frame, and the primary path and the backup path of the first network device are carried in the extended management frame;

[0075] Alternatively, the second unicast message includes a path response frame, and the primary path and the backup path of the first network device are carried in the path response frame. In a possible implementation, the sending module is further used to send a routing reset message to the second network device through the backup path after a link failure in the primary path, and the routing reset message is used to indicate a link failure in the primary path.

[0076] A fourth aspect of the present application provides a network device, the network device comprising:

[0077] A receiving module, used for receiving a plurality of link information, the plurality of link information comes from a plurality of network devices in the wireless mesh network, and the plurality of link information is used for indicating the link status between different network devices and neighboring devices respectively;

[0078] a processing module, configured to determine a primary path and a backup path of a first network device based on multiple link information, wherein the multiple network devices include the first network device, the primary path and the backup path are both used to indicate a path for the first network device to forward data, the primary path includes a link between the first network device and a first neighboring device, and the backup path includes a link between the first network device and a second neighboring device;

[0079] The sending module is used to send a primary path and a backup path to the first network device, where the backup path is used to be enabled when a link in the primary path fails.

[0080] In one possible implementation, the receiving module is also used to receive a first broadcast message from a first network device, the first broadcast message includes first link information, the first link information is used to indicate the link status between the first network device and a neighboring device, and the link information between a child node device of the first network device and a neighboring device.

[0081] In a possible implementation manner, the first broadcast message includes a Beacon frame, and the first link information is carried in an extension field or a Vendor Specific field in the Beacon frame.

[0082] In a possible implementation, the receiving module is further used to receive a first unicast message sent by the child node device, where the first unicast message includes first link information, and the first link information is used to indicate a link status between the first network device and a neighboring device.

[0083] In a possible implementation manner, the first unicast message includes an extended management frame, and the first link information is carried in the extended management frame;

[0084] Alternatively, the first unicast message includes a PREP frame, and the first link information is carried in the PREP frame.

[0085] In a possible implementation, the sending module is further used to send a second broadcast message, where the second broadcast message includes a primary path and a backup path;

[0086] Alternatively, the sending module is further configured to send a second unicast message, where the second unicast message includes a primary path and a backup path.

[0087] In a possible implementation manner, the second broadcast message includes a second Beacon frame, and the primary path and the backup path are carried in an extended field or a Vendor Specific field in the second Beacon frame.

[0088] In a possible implementation, the second unicast message includes an extended management frame, and the primary path and the backup path are carried in the extended management frame;

[0089] Alternatively, the second unicast message includes a PREP frame, and the primary path and the backup path are carried in the PREP frame.

[0090] In a possible implementation manner, the first link information includes an identifier of the first network device, the number of neighbor devices, identifiers of the neighbor devices, and link quality metrics between the first network device and the neighbor devices.

[0091] In a possible implementation manner, the primary path and the backup path include at least one of the following: path priority, path hop count, and identification of a network device that the path passes through.

[0092] In a possible implementation, the sending module is further configured to send a routing broadcast message, where the routing broadcast message includes a primary path and a backup path of each network device in the plurality of network devices.

[0093] In one possible implementation, the receiving module is further used to receive a routing reset message from the first network device, where the routing reset message is used to indicate a link failure in the primary path; the processing module is further used to determine a new primary path and a new backup path corresponding to the first network device based on the routing reset message; and the sending module is further used to send the new primary path and the new backup path to the first network device.

[0094] A fifth aspect of the present application provides a network device, which includes: a memory and a processor; the memory stores code, and the processor is configured to execute the code. When the code is executed, the network device executes a method as implemented in any one of the first aspect or the second aspect.

[0095] A sixth aspect of the present application provides a communication system, which includes the network device as described in the third aspect and the network device as described in the fourth aspect.

[0096] The seventh aspect of the present application provides a computer-readable storage medium, which stores a computer program. When the computer-readable storage medium is run on a computer, the computer executes a method as implemented in any one of the first aspect or the second aspect.

[0097] An eighth aspect of the present application provides a computer program product, which, when executed on a computer, enables the computer to execute a method as implemented in any one of the first or second aspects.

[0098] In a ninth aspect, the present application provides a chip, comprising one or more processors, wherein some or all of the processors are used to read and execute a computer program stored in a memory to execute the method in any one of the implementations of the first or second aspect.

[0099] Optionally, the chip includes a memory, and the memory is connected to the processor through a circuit or wire. Optionally, the chip also includes a communication interface, and the processor is connected to the communication interface. The communication interface is used to receive data and / or information to be processed, and the processor obtains the data and / or information from the communication interface, processes the data and / or information, and outputs the processing results through the communication interface. The communication interface can be an input and output interface. The method provided in the present application can be implemented by one chip, or by multiple chips in collaboration.

[0100] Among them, the technical effects brought about by any design method in the second to ninth aspects can refer to the technical effects brought about by different implementation methods in the above-mentioned first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0101] Figure 1 A schematic diagram of the structure of a single-hop wireless network provided in an embodiment of the present application;

[0102] Figure 2 A schematic diagram of the structure of a wireless mesh network provided in an embodiment of the present application;

[0103] Figure 3 A schematic diagram of deploying a wireless mesh network in an open-pit mine scenario provided in an embodiment of the present application;

[0104] Figure 4 A schematic diagram of a wireless link of a wireless mesh network provided in an embodiment of the present application;

[0105] Figure 5 A flowchart of a communication recovery method for a link failure provided in an embodiment of the present application;

[0106] Figure 6 A schematic diagram of a tree topology constructed based on a wireless mesh network provided in an embodiment of the present application;

[0107] Figure 7 A schematic diagram of a link status reporting process according to an embodiment of the present application;

[0108] Figure 8 This is a schematic diagram of the format of a Beacon frame provided in the IEEE802.11s standard;

[0109] Fig. 9 A schematic diagram of the format of a Neighbor Link Report element field provided in an embodiment of the present application;

[0110] Fig.10A schematic diagram of carrying link information through a Neighbor Link Report element field provided in an embodiment of the present application;

[0111] Fig.11 A schematic diagram of another embodiment of the present application providing link information carried by a Neighbor Link Report element field;

[0112] Fig.12 A schematic diagram of a process of feeding back link information via a unicast message provided in an embodiment of the present application;

[0113] Fig.13 A schematic diagram of a primary path and a backup path of a device node provided in an embodiment of the present application;

[0114] Fig.14 A schematic diagram of the format of a path information field provided in an embodiment of the present application;

[0115] Fig.15 A schematic diagram of a process for a root node device to send path information to a network device provided in an embodiment of the present application;

[0116] Fig.16 A schematic diagram of a process for sending path information provided in an embodiment of the present application;

[0117] Fig.17 A schematic diagram of a switching backup path provided in an embodiment of the present application;

[0118] Fig.18 A schematic diagram of a process of switching to a backup path provided in an embodiment of the present application;

[0119] Fig.19A A schematic diagram of a node in a wireless mesh network switching a path and connecting to another wireless mesh network provided in an embodiment of the present application;

[0120] Fig.19B A schematic diagram of a network management system monitoring the link status in a wireless mesh network provided in an embodiment of the present application;

[0121] Fig.19C A schematic diagram of implementing load sharing based on link status in a wireless mesh network provided in an embodiment of the present application;

[0122] Fig. 20 A schematic diagram of the structure of a network device provided in an embodiment of the present application;

[0123] Fig.21 A schematic diagram of the structure of a network device provided in an embodiment of the present application;

[0124] Fig. 22 A schematic diagram of the structure of a network device provided in an embodiment of the present application;

[0125] Fig.23 A schematic diagram of the structure of a computer-readable storage medium provided in an embodiment of the present application. DETAILED DESCRIPTION

[0126] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0127] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0128] WLAN technology based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard has been widely used in the enterprise, consumer, and operator markets. Users can easily access the Internet through these wireless LANs.

[0129] In mainstream WLANs, each client accesses the network through a wireless link connected to an AP, forming a local Basic Service Set (BSS). To communicate with any terminal in the network, the user must first access the AP. This network structure is called a single-hop wireless network. In order to expand the wireless coverage area, it is often necessary to connect multiple APs with cables, switches, power supplies and other equipment to form a larger WLAN.

[0130] For example, see Figure 1 , Figure 1 A schematic diagram of the structure of a single-hop wireless network provided in an embodiment of the present application. Figure 1As shown in the figure, stations (STAs) connected to different APs need to be forwarded through a wired network, where STAs refer to terminal devices such as smartphones, laptops, and tablets. When STAs access external networks, only one hop on the path is a wireless connection, and the rest are wired connections.

[0131] In a single-hop wireless network, each AP needs to be connected to a wired network. When wireless coverage is required over a large area, a lot of time is required for installation and deployment, which is costly. Once the AP is deployed, it is difficult to move it.

[0132] A wireless mesh network is a multi-hop wireless network. The biggest difference between it and a traditional single-hop wireless network is that it uses wireless connections instead of wired connections to connect multiple APs. The APs in a wireless mesh network not only provide user access functions, but also forward data on wireless links, so that data is routed from one AP to another, and finally accesses the wired network through a portal node, thus forming a wireless mesh network.

[0133] For example, see Figure 2 , Figure 2 A schematic diagram of the structure of a wireless mesh network provided in an embodiment of the present application. Figure 2 As shown in FIG, according to different functions in the wireless mesh network, AP can be divided into three roles: mesh point (MP), mesh portal point (MPP) and mesh access point (MAP).

[0134] MP refers to a node in a Mesh network that uses IEEE 802.11 MAC and PHY protocols for wireless communication and supports Mesh functions. MP supports automatic topology, automatic discovery of routes, and forwarding of data packets. Generally speaking, MP is also called AP.

[0135] MAP refers to any MP that supports AP functions and can provide access functions for STAs. MAP can be considered as a special Mesh Point.

[0136] MPP refers to a node that connects a wireless mesh network and other types of networks and communicates with other nodes within the mesh network. MPP has a portal function, through which nodes within the wireless mesh network can communicate with external networks. MPP can also be considered a special MP.

[0137] Wireless mesh networks eliminate the need for wiring between APs, making installation options more flexible. In a wireless mesh network, if you want to add a new device, you simply need to plug it in, and it will automatically configure and determine the best multi-hop transmission path. When adding or moving AP devices, the network can automatically detect topology changes and automatically adjust communication routes to obtain the most efficient transmission path.

[0138] Compared with traditional WLAN networks, wireless mesh networks can significantly reduce deployment costs and provide greater convenience and scalability. Therefore, in addition to being used in common scenarios of traditional WLANs such as enterprise networks, office networks, and campus networks, wireless mesh networks are also widely used in large warehouses, port terminals, mine tunnels, emergency communications, and other scenarios where wiring is inconvenient or the wiring cost is high. At present, IEEE802.11s standardization of wireless mesh networks mainly focuses on wireless mesh network establishment, wireless mesh network security, and mesh data packet routing, which focuses on solving the connectivity problem of wireless mesh networks.

[0139] However, with the widespread application of wireless mesh networks, the inventors have found that wireless mesh networks have some other problems. For example, in some scenarios, the wireless channels between APs may change dramatically, and even the location of the AP may move. For example, see Figure 3 , Figure 3 The following is a schematic diagram of deploying a wireless mesh network in an open-pit mine scenario provided by an embodiment of the present application. Figure 3 As shown in the figure, in the open-pit mine scenario, the wireless link between APs may be blocked by the moving tall mining vehicles, causing the link quality to drop sharply or even become unavailable. In addition, some APs are installed on vehicles and may move as mining progresses.

[0140] In general, the existing IEEE802.11s standard mainly solves the problem of network connectivity between APs using wireless connections. It does not take into account the situation where the network topology needs to be dynamically adjusted, and does not pay attention to the situation where the wireless links between APs may change dramatically during use. As a result, wireless mesh networks are prone to large network delays, data packet loss, and even service interruptions in actual use, making it difficult to meet actual business needs.

[0141] In view of this, the embodiment of the present application provides a communication recovery method for link failure, in which the network device in the wireless mesh network first searches for the link status between the network device and the neighboring device, and reports the link status between the network device and the neighboring device to the designated device of the wireless mesh network, so that the designated device can issue the main path and backup path for each network device to guide the network device to transmit data according to the link status between the network devices in the entire wireless mesh network. In this way, the network devices in the wireless mesh network can use the main path to transmit data during the working process, and when the link of the main path fails, it can quickly switch to the backup path issued in advance to avoid business interruption and ensure the normal operation of the business when the link between the network devices fails.

[0142] For example, see Figure 4 , Figure 4 A wireless link diagram of a wireless mesh network provided in an embodiment of the present application. Figure 4 The application scenario shown includes multiple APs, namely AP1-AP9. Among them, AP1 is connected to the external network through a wired connection and is an MPP. AP5-AP9 are connected to terminal devices and are the above-mentioned MAPs, responsible for providing wireless access functions for terminal devices. AP2-AP4 provide a backhaul link from AP5-AP9 to the MPP and are the above-mentioned MPs. That is to say, in a wireless mesh network, except for AP1 as an MPP that is connected to the external network through a wired connection, other APs are connected wirelessly and provide data forwarding functions for terminal devices through interconnected wireless links. It should be noted that in Figure 4 In the figure, the dotted line between APs indicates that the APs can send and receive wireless signals to each other, and does not represent the data transmission path used between the APs.

[0143] Specifically, the fast rerouting process, that is, the process of selecting a new link to restore network connectivity after a wireless link fails, can include the following three stages: link reselection triggering stage, target link search stage and link reselection execution stage.

[0144] Among them, the link reselection triggering phase refers to making a switching decision at the most appropriate time to prevent the channel conditions from deteriorating excessively, and the time consumption is related to the link monitoring strategy.

[0145] The target link search phase refers to obtaining a new target link by searching the wireless channel. This phase solves the problem of how to determine the new target node as quickly as possible, and the new target node can provide connectivity to the wireless mesh network with good link quality. Traditional devices usually take hundreds of milliseconds or even longer to complete this process.

[0146] The link reselection execution phase refers to the channel switching operation performed by the radio interface, which can usually be completed within a few milliseconds.

[0147] During the search phase, the service data packets cannot be transmitted normally, and the search phase takes too long, which is the main reason for the interruption of service data. Therefore, the core of the embodiment of the present application is how to reduce or even eliminate the delay caused by the target link search process.

[0148] Since the target link search is the process of obtaining a new available link, if the information of the new link that the node needs to switch to is known a priori, that is, the node can know the information of the backup path when it detects a link break, then the search phase can be cancelled. In this case, only a simple search operation needs to be performed locally to obtain the information of the target link to be connected, and the link reselection is performed directly, switching to the backup path, so that the node can recover from the link failure and avoid service interruption.

[0149] Therefore, the core of this embodiment is to solve how to efficiently and in real time maintain backup path information for nodes, so that after a link failure occurs, the node can accurately and quickly switch to the backup path. This includes the following four core steps.

[0150] Step 1, determine the initial network topology: configure the designated node of the wireless mesh network as the master node, such as designating the mesh network entry node MPP as the master node, and other nodes as slave nodes. Build a tree or forest topology with the master node as the root node, and obtain the path from each slave node to the master node. For example, in the following embodiment, the first network device is a slave node, and the second network device is a master node.

[0151] Step 2: Distributed monitoring and reporting of link status: Each slave node monitors the link status of its neighbor nodes and reports the link quality to its parent node layer by layer until the master node.

[0152] Step 3: Centralized generation and distribution of routing strategies: The master node calculates the primary path and backup path from each node to the root node based on the neighbor node link information reported by each node, and distributes them to each slave node.

[0153] Step 4, fast rerouting: Each slave node keeps monitoring the link between itself and its parent node. If a link failure is found, it directly establishes a link with the parent node of the optimal backup path based on the locally saved backup path information to achieve fast rerouting and notify the master node. The master node can regenerate the routing policy and issue it to adjust the route adopted by the failed node.

[0154] See also Figure 5 , Figure 5 A flowchart of a communication recovery method for link failure provided in an embodiment of the present application. Figure 5As shown, the communication recovery method for link failure provided in the embodiment of the present application includes the following steps 501-506.

[0155] Step 501: A first network device measures a link status between the first network device and a neighboring device.

[0156] In this embodiment, the first network device is any device other than the master node device in the wireless mesh network, such as a physical device such as a router, a wireless switch, or a wireless transceiver. Specifically, the first network device can be a device that provides wireless access services for user terminal devices in the wireless mesh network, or a device that establishes a wireless connection with other network devices in the wireless mesh network to provide data forwarding functions. For example, the first network device can be Figure 4 Any AP among AP2-AP9 in the wireless mesh network shown.

[0157] After the first network device is started, the first network device can measure the link status between itself and the surrounding neighboring devices. Among them, the neighboring device of the first network device can be one or more, and this embodiment does not limit the number of neighboring devices of the first network device. Specifically, the first network device measures the link status between itself and the neighboring device by first searching for the surrounding neighboring devices and measuring the quality of the link between itself and the searched neighboring devices. For example, the first network device can measure the strength of the wireless signal sent by the neighboring device to determine the quality of the link between the first network device and the neighboring device. Exemplarily, the first network device can obtain the quality of the link with the neighboring device by measuring the signal-to-noise ratio (SNR) of the wireless signal or the received signal strength indicator (RSSI).

[0158] In general, the first network device can determine one or more neighbor devices around the first network device by measuring the link status between itself and the neighbor device, and can obtain the quality of the link between the first network device and each neighbor device.

[0159] Step 502: The first network device sends first link information to the second network device, where the second network device is a master node device in the wireless mesh network. The first link information is used to indicate a link status between the first network device and a neighboring device.

[0160] After completing the measurement of the link status between itself and the neighboring devices, the first network device can send the first link information to the second network device, thereby realizing feedback of the link status between itself and the surrounding neighboring devices to the main node device in the wireless mesh network. Among them, the second network device is a designated device in the wireless mesh network, which is used to receive the link information reported by other network devices in the wireless mesh network, and then issue the corresponding main path and backup path to each network device based on the acquired link information. In the case where the wireless mesh network completes the construction of the tree topology, the second network device is the root node device in the tree topology. For example, the second network device is the boundary device between the external network and the wireless mesh network, and is responsible for providing the network devices in the wireless mesh network with the function of accessing the external network. For example, the second network device is connected to the external network by wire, and is connected to other network devices in the wireless mesh network by wireless.

[0161] Depend on Figure 4 It can be seen that each network device in the wireless mesh network is connected to other network devices, and only some network devices (such as AP2-AP4) are directly connected to the root node device, while other network devices (such as AP5-AP9) are connected to the root node device through their parent node devices. Figure 4 In the example, the parent node devices of AP5-AP9 are directly connected to the root node device. Figure 4 The wireless mesh network in the example can actually be divided into three layers. The first layer is AP1 as the root node device, the second layer is AP2-AP4 with links to the root node device, and the third layer is AP5-AP9 connected to the root node device through a parent node device. In actual applications, the parent node devices of some APs may also have parent node devices that are not directly connected to the root node device, which makes the wireless mesh network actually have more than three layers of structure.

[0162] Therefore, in the process of the first network device sending the first link information to the second network device, if there is a direct link between the first network device and the root node device, the first network device can send the first link information directly to the root node device without forwarding it through other network devices; if there is no direct link between the first network device and the root node device, the first network device can send the first link information to the parent node device of the first network device, and the parent node device of the first network device will continue to send the first link information to the parent node device of the upper layer, and so on, ultimately realizing the forwarding of the first link information to the second network device.

[0163] Step 503: The root node device receives a plurality of link information, where the plurality of link information comes from a plurality of network devices in the wireless mesh network, and the plurality of link information is used to indicate link status between different network devices and neighboring devices, respectively.

[0164] Since each network device except the root node device in the wireless mesh network will perform the process of measuring the link status between itself and the neighboring device, and send link information indicating the link status between itself and the neighboring device to the root node device, the root node device can receive multiple link information. In addition, the multiple link information received by the root node device comes from different network devices in the wireless mesh network, and each link information is used to indicate the link status between the network device of the link information and the neighboring device.

[0165] For example, Figure 4 Taking the wireless mesh network shown in the figure as an example, AP1 as the root node device can receive 8 link information through AP2-AP4, and these 8 link information come from AP2-AP9 respectively. In addition, the 8 link information are used to indicate the link status between each AP in AP2-AP9 and its neighboring devices measured by itself.

[0166] Step 504: The root node device determines a primary path and a backup path of the first network device based on multiple link information.

[0167] After the root node device obtains the link information reported by different network devices in the wireless mesh network, the root node device can determine the link status between the network devices in the wireless mesh network based on the link information, thereby planning a corresponding data transmission path for any network device in the wireless mesh network. The data transmission path can be used to indicate the path for the network device to transmit data to the root node device.

[0168] Taking the first network device in the wireless mesh network as an example, the root node device can determine the main path and backup path of the first network device based on multiple link information from multiple network devices. Among them, the main path and the backup path are both used to indicate the path for the first network device to forward data (that is, how the first network device sends data to the root node device), the main path includes the link between the first network device and the first neighbor device, and the backup path includes the link between the first network device and the second neighbor device. The first neighbor device and the second neighbor device are both neighbor devices of the first network device, and can assist in forwarding the data sent by the first network device. That is, the main path and the backup path are respectively used to instruct the first network device to send data to the root node device through different neighbor devices, thereby ensuring that when a link in the main path fails, the first network device can also send data to the root node device through the backup path.

[0169] The first link information sent by the first network device includes the link status between the first network device and the first neighboring device and the link status between the first network device and the second neighboring device. Moreover, the link status between the first network device and the first neighboring device and the link status between the first network device and the second neighboring device both meet the data transmission requirements, so the root node device determines that the main path includes the link between the first network device and the first neighboring device, and the backup path includes the link between the first network device and the second neighboring device.

[0170] In this embodiment, the root node device can use a pre-configured path selection algorithm to determine the main path and the backup path for the network devices in the wireless mesh network. This embodiment does not specifically limit the path selection algorithm. For example, the root node device comprehensively considers the link quality between network devices and the load balancing of the links, and tries to allocate a main path and a backup path with higher link quality to each network device, and the main paths corresponding to different network devices can have a relatively balanced load.

[0171] It should be noted that the root node device may send a primary path and one or more backup paths to the first network device. That is, for any network device, there is only one primary path corresponding to the network device, and there may be one or more backup paths.

[0172] Step 505: The root node device sends the primary path and the backup path to the first network device.

[0173] After determining the primary path and the backup path of the first network device, the root node device can send the primary path and the backup path to the first network device. In the case where there is a link between the first network device and the root node device, the root node device can directly send the primary path and the backup path to the first network device. In the case where there is no directly connected link between the first network device and the root node device, the root node device can send the primary path and the backup path to the first network device through other network devices between the first network device and the root node device.

[0174] Step 506: When a link in the primary path fails, the first network device forwards data through the backup path.

[0175] After the first network device receives the primary path and the backup path, the first network device can save the primary path and the backup path. In addition, during the operation of the first network device, the first network device forwards data through the primary path. For example, when the first network device is connected to a terminal device, the first network device forwards data sent by the terminal device through the primary path; for another example, when the first network device is not connected to a terminal device, the first network device receives data from the terminal device from other network devices and forwards the received data based on the primary path.

[0176] In addition, when the first network device detects a link failure on the primary path with the first neighbor device, the first network device can query the pre-saved backup path and switch to the backup path to forward data. That is, when the link between the current network device and the neighbor device on the primary path fails, the first network device quickly switches from the primary path to the pre-saved backup path, so that the data obtained by the first network device can be forwarded through the backup path.

[0177] Optionally, after a link failure in the primary path, the first network device can send a routing reset message to the second network device through the backup path, and the routing reset message is used to indicate the link failure in the primary path. In other words, the routing reset message is equivalent to notifying the second network device that a failure has occurred in the primary path used by the first network device, and the first network device has switched to the backup path. Therefore, the second network device can re-plan a new path for the first network device, and then send a more accurate new path to the first network device.

[0178] Specifically, after receiving the routing reset message, the second network device determines a new primary path and a new backup path for the first network device based on the routing reset message, and sends the new primary path and the new backup path to the first network device to ensure that the first network device can subsequently forward data.

[0179] In addition, since the faulty link is also indicated in the routing reset message, when the second network device receives data from the external network and destined for the first network device, the second network device can forward the data to the first network device based on the newly enabled path, thereby bypassing the faulty link and ensuring that the first network device can smoothly receive the data.

[0180] For ease of understanding, the specific process of exchanging link information and paths between the first network device and the root node device in the wireless mesh network will be described in detail below.

[0181] First, the process of exchanging link information between the first network device and the root node device is introduced. There are many ways for the first network device and the root node device to exchange link information.

[0182] Mode 1: The first network device sends the first link information to the root node device by sending a broadcast message.

[0183] Exemplarily, the first network device sends a first broadcast message, and the first broadcast message includes the first link information. For example, the first broadcast message includes a beacon frame, and the first link information is carried in an extended field or a vendor-specific field in the Beacon frame. In this way, when the root node device is the parent node device of the first network device, the root node device can receive the first broadcast message sent by the first network device, thereby enabling the first network device to send the first link information to the root node device. In the case where the root node is not the parent node device of the first network device, the parent node device of the first network device will receive the first broadcast message sent by the first network device, and then continue to forward the first link information in the first broadcast message. By analogy, each network device with a child node device will forward the link information in the broadcast message after receiving the broadcast message from the child node device, thereby ensuring that the first link information sent by the first network device through the first broadcast message can be forwarded to the root node device.

[0184] Optionally, when the first network device has a child node device, the first network device receives the second link information sent by the child node device, and the second link information is used to indicate the link status between the child node device and the neighboring device of the child node device. Then, the first network device forwards the second link information to the second network device as the root node device. In this solution, when the parent node device receives the link information broadcast by the child node device, the parent node device forwards the link information to the child node device, thereby realizing the step-by-step reporting of link information in the wireless mesh network, ensuring that the link information measured by all network devices can be reported to the root node device.

[0185] For example, after receiving the second link information, the first network device sends a second broadcast message to the second network device, and the second broadcast message includes the first link information and the second link information. That is, the first network device carries the link information measured by itself and the link information measured by the sub-node device through one broadcast message, thereby reducing message overhead and improving the transmission efficiency of link information.

[0186] Specifically, when the wireless mesh network has completed the topology construction, each network device in the wireless mesh network can store the path information to the root node device, as well as the parent node device information and all child node information of the device in the network topology. In this way, each network device can send link information to the root node device based on the stored path information and parent node and child node device information.

[0187] For example, the tree topology of the wireless mesh network can be determined by using the proactive tree building mode defined in the IEEE802.11 standard. In a wireless mesh network, a network device connected to an external network by wire (i.e., the above-mentioned MPP) is usually configured as a master node, and the remaining network devices are slave nodes. For example, in the above-mentioned embodiment, the second network device is the master node, and the first network device is the slave node.

[0188] The master node will act as the root node of the tree and initiate the active tree construction process. The active tree construction process can use the active root announcement (RANN) mechanism defined in IEEE802.11, where the master node announces itself as the root node of the tree to other nodes, builds a tree topology, and completes the construction of the network topology. After the tree topology is built, each slave node stores the routing information to the root node and the parent node information of each node in the tree topology. The master node stores the routing information of the entire tree topology. For example, please refer to Figure 6 , Figure 6 A schematic diagram of a tree topology based on a wireless mesh network provided in an embodiment of the present application. Figure 6 As shown, for Figure 4 The wireless mesh network shown in the figure can be constructed into a tree topology. Among them, AP1 is the main node, that is, the root node in the tree topology. In addition, AP1 is the parent node of AP2-AP4, AP2 is the parent node of AP5 and AP6, AP4 is the parent node of AP9, and AP3 is the parent node of AP7 and AP8.

[0189] After the tree topology is established, each slave node in the wireless mesh network will measure the link status between all neighbor nodes and report the link status between all neighbor nodes to the parent node in the form of link information. After the parent node receives the link information reported by the child node, it attaches the link information of the node and continues to report to the upper node (the parent node of the current parent node) until it is reported to the root node.

[0190] by Figure 6 Taking the established tree topology as an example, the route from AP9 to the root node AP1 is AP9→AP4→AP1. The link measurement and reporting process between these three nodes is as follows: Figure 7 As shown, Figure 7 A schematic diagram of a link status reporting process according to an embodiment of the present application. Figure 7 In the process of link status reporting, the link status reporting includes the following process.

[0191] First, AP9 and AP4, as slave nodes, will measure the link status between themselves and all neighboring devices in real time. That is, AP9 will measure the link status between AP9 and all neighboring devices and store the measured link status results; AP4 will also measure the link status between AP4 and all neighboring devices and store the measured link status results.

[0192] Then, when AP9 needs to report the link status to the root node (for example, the reporting period has expired, or the change in link quality between AP9 and neighboring devices exceeds a preset threshold), it directly reports the link status between AP9 and all neighboring devices to the parent node (i.e., AP4) on the route. Figure 4 Taking the wireless mesh network shown as an example, the link status reported by AP9 includes the link status between AP9 and AP4, and the link status between AP9 and AP2. AP9 reports the link status to the parent node AP4 by broadcasting messages.

[0193] Secondly, after receiving the link status reported by AP9, AP4 verifies whether it is a link status report from a child node. After confirming that the link status reported by AP9 is the link status reported by its own child node, it stores the link status reported by the child node (i.e., the neighbor link measurement result reported by the child node), and generates a link status report message of this node in combination with the link status measured by this node, and further sends a link status report message to the parent node of the upper level. Among them, the link status report message sent by AP4 to the parent node AP1 includes the link status reported by AP4's child node AP9, as well as the link status measured by this node (such as the link status between AP4 and AP1, the link status between AP4 and AP2, the link status between AP4 and AP3, the link status between AP4 and AP6, and the link status between AP4 and AP9).

[0194] In the process of using broadcast messages to report link status, one implementation method is to reuse the existing Beacon mechanism and add the measured link status between the neighboring device to the Beacon frame.

[0195] Among them, Beacon frames are broadcast frames periodically sent by APs in wireless mesh networks to let other nodes know the existence of the current AP and the main information of this AP. According to the definition of the IEEE802.11s standard, all nodes in a wireless mesh network need to periodically send Beacon frames. Therefore, this solution can use the periodic broadcast of Beacon frames to realize the reporting of link status.

[0196] For example, see Figure 8 , Figure 8Figure 1 is a schematic diagram of the format of a Beacon frame provided in the IEEE802.11s standard. Figure 8 As shown in the figure, in the Frame Body of the Beacon frame, the front part is mandatory fields, such as Timestamp, Beacon interval, Capability Information, and Service Set Identifier (SSID), and the back part is optional fields, such as Traffic Indication Map (TIM), Country, Power Constraint, and Vendor Specific. The last optional field is the Vendor Specific field, which can have one or more fields and is placed at the end of the Beacon frame.

[0197] When using the broadcast Beacon frame to report link information, a newly defined field for carrying link information, such as the Neighbor Link Report element field, can be used. That is, a new field (i.e., the Neighbor Link Report element field) is extended in the Beacon frame, and the link information is carried through the field.

[0198] For example, see Fig. 9 , Fig. 9 A schematic diagram of the format of a Neighbor Link Report element field provided in an embodiment of the present application. Fig. 9As shown, the Neighbor Link Report element field used to carry link information may include device identification, number of neighbor devices, neighbor device identification, and link quality measurement value. Among them, the device identification and neighbor device identification are both used to uniquely identify a network device in the wireless mesh network, and can be specifically represented by a Media Access Control Address (MAC Adress). The link quality measurement value is used to measure the quality of the wireless link between two network devices in the wireless mesh network, and can be specifically represented by the Link Metric defined in the protocol. Specifically, the link quality measurement value can be measured using indicators such as RSSI or SNR. In a Beacon frame, one or more Neighbor Link Report element fields may be included, and each Neighbor Link Report element field corresponds to a link status reported by a network device.

[0199] exist Figure 7 In the example shown, when AP9 reports information about two neighbor links (AP9<->AP4, AP9<->AP2) to AP4, the following information can be added to the Beacon frame sent by AP9: Fig.10 The Neighbor Link Report element fields are shown. Fig.10 A schematic diagram of carrying link information through the Neighbor Link Report element field provided in an embodiment of the present application. Fig.10 In the broadcast message, the Neighbor Link Report element field added by AP9 carries the link information measured by AP9, including the MAC address of AP9, the number of neighbor devices measured by AP9 (2), the MAC address of the first neighbor device (AP4), the quality measurement value of the link between AP9 and AP4, the MAC address of the second neighbor device (AP2), and the quality measurement value of the link between AP9 and AP2.

[0200] Furthermore, when AP4 reports its own neighbor link and the neighbor link of its child node AP9 to AP1, the neighbor link reported by AP9 can be added to the sent Beacon frame (such as Fig.10 The content shown in the figure) is then used in another NeighborLink Report element field to attach the five neighbor link information measured by AP4 (AP4<->AP1, AP4<->AP2, AP4<->AP3, AP4<->AP6, AP4<->AP9), as shown in the figure. Fig.11 shown.

[0201] Considering that in a wireless mesh network, when the network devices at both ends measure the quality of the same link, the measurement results are likely to be consistent. For example, in the above example, the Link Metric value between AP9<->AP4 reported by AP9 to AP4 may be the same as the Link Metric value between AP4<->AP9 measured by AP4 itself. In this case, AP4, as the parent node, can omit the Link Metric of AP4<->AP9 in its own neighbor link measurement results, that is, only report the remaining 4 neighbor link information, thereby saving message overhead.

[0202] Since the Beacon frame can also contain one or more Vendor Specific fields, the link information measured by the network device can also be reported in the Vendor Specific field, that is, the link information is placed in the existing field of the Beacon frame for transmission. Among them, the advantage of carrying the link information in the original Vendor Specific field is that it does not affect the interoperability of different manufacturers, and avoids errors when the third-party manufacturer's equipment parses the Beacon frame when the link information is placed in other original fields.

[0203] Mode 2: The first network device sends the first link information to the root node device by sending a unicast message.

[0204] The unicast message sent by the first network device includes the first link information, and the destination address of the unicast message is the address of the root node device.

[0205] Specifically, if unicast messages are used to report link status, a new management frame can be defined to carry link information. That is, the unicast message sent by the first network device includes an extended management frame, and the first link information can be carried in the extended management frame. In addition, when unicast messages are used to report link status, new fields can also be extended in the existing management frames of the IEEE802.11 standard. For example, in an existing Mesh Link Metric Report frame, one or more newly defined fields that carry neighbor node link information are extended, such as the Neighbor Link Report element field defined above, and the link information is carried through the newly extended Neighbor Link Report element field and sent to the root node device.

[0206] Optionally, the process of the network device reporting link information via unicast messages may also be performed during the process of establishing the network topology, wherein the link information may be used as input for establishing the network topology.

[0207] Specifically, in the IEEE802.11 standard, the proactive root node announcement RANN mechanism is used to determine the route from the root node to each node in the wireless mesh network. The proactive RANN mechanism mainly includes the following processes:

[0208] The root node broadcasts the RANN message. Each node that receives the RANN message needs to further propagate the RANN message so that the RANN message can be propagated to all nodes in the wireless mesh network.

[0209] The node that receives the RANN message unicasts a Path Request (PREQ) frame to the root node;

[0210] The root node returns a unicast Path Reply (PREP) frame for each PREQ received.

[0211] In this embodiment, a node that receives RANN can carry the link information measured by the node in a PREQ and send it to the root node. Fig.12 , Fig.12 A schematic diagram of a process of feeding back link information via a unicast message is provided in an embodiment of the present application. Fig.12 As shown, in the PREP frames sent by AP4 and AP9, a new Neighbor Link Report element field is added. The format of the Neighbor Link Report element field can refer to the definition in the previous embodiment. Among them, the Neighbor Link Report element field in the PREP frame sent by AP4 carries the link status between AP4 and all neighboring devices; the Neighbor Link Report element field in the PREP frame sent by AP9 carries the link status between AP9 and all neighboring devices. In this way, when the master node receives the PREP from all slave nodes, it can know the link status between each node and the neighboring node in the entire wireless mesh network.

[0212] In general, using broadcast messages to report link status is suitable for slave nodes to periodically report neighbor link status; using unicast messages to report link status is suitable for slave nodes to report neighbor link status after an event is triggered. The combination of the two different reporting methods enables the master node to grasp the link quality of each node in the entire network in real time.

[0213] After the network devices in the wireless mesh network report the link status between themselves and the neighboring devices to the root node device, the root node device can obtain the status of each link in the entire wireless mesh network. In this way, the root node device can select the main path and backup path for each network device in the wireless mesh network according to the pre-set routing selection method.

[0214] For example, see Fig.13 , Fig.13 A schematic diagram of a primary path and a backup path of a device node provided in an embodiment of the present application. Fig.13 As shown in the figure, AP1 as the root node device can obtain the quality metric value of each link in the entire wireless mesh network. For example, the quality metric value of the link between AP1 and AP2 is 0.2, the quality metric value of the link between AP2 and AP9 is 0.8, the quality metric value of the link between AP1 and AP4 is 0.3, and the quality metric value of the link between AP4 and AP9 is 0.4. Among them, the main path and backup path planned by AP1 for AP9 are shown in the following Table 1.

[0215] Table 1

[0216]

[0217] As shown in Table 1, the primary path planned by AP1 for AP9 is AP1-AP4-AP9, and the quality metric value of the path is 0.6; the backup path planned by AP1 for AP9 is AP1-AP2-AP9, and the quality metric value of the path is 0.8.

[0218] Among them, the backup paths planned by the root node device for the network devices in the wireless mesh network can be determined according to the actual link conditions, for example, one or more backup paths are planned for a network device, and this implementation does not make specific limitations on this.

[0219] When the root node device sends the main path and backup path to the network device, a newly defined field can be used in the message sent to carry the main path and backup path, for example, a new route information field (RouteInformation element) is defined to carry the path information. Specifically, each path can be carried in a route information field. The Route Information element field will indicate the information of all network devices that the path passes through.

[0220] For example, see Fig.14 , Fig.14 The following is a schematic diagram of the format of a path information field provided in an embodiment of the present application. Fig.14 As shown, the Route Information element field may include the quality metric of the path, the number of hops, and the identification of each network device passed through. The quality metric of the path may be used to identify the priority of the route, and the identification of the network device may use the MAC address of the network device.

[0221] The management frame sent by the root node device to the network device in the wireless mesh network may contain one or more Fig.14 As shown in the Route Information element fields, each Route Information element field represents a path (such as the main path or backup path mentioned above) allocated by the root node device to the network device.

[0222] In addition, when the root node device sends the primary path and the backup path to the network device, a broadcast message or a unicast message may be used to implement the path sending.

[0223] When the root node device adopts a unicast message sending path, the root node device may carry the primary path and the backup path planned for the specific network device in the unicast message sent to the specific network device.

[0224] For example, see Fig.15 , Fig.15 A schematic diagram of a process for a root node device to send path information to a network device provided in an embodiment of the present application. Fig.15 As shown, AP1 as a root node device can carry the main path and backup path between AP1 and AP4 in the path response frame sent to AP4; AP1 as a root node device can carry the main path and backup path between AP1 and AP9 in the path response frame sent to AP9, thereby realizing the sending of the main path and backup path during the construction of the network topology.

[0225] When the root node device uses a broadcast message to send a path, the root node device can carry the main path and backup path corresponding to all slave node devices in the wireless mesh network in the broadcast message. Then, the network device that receives the broadcast message determines the main path and backup path of the device based on the broadcast message, and continues to forward the broadcast message, so that the child node devices of the current network device can also receive the broadcast message, and finally ensure that the broadcast message sent by the root node device can be spread throughout the wireless mesh network.

[0226] Optionally, after receiving the broadcast message, the network device in the wireless mesh network may remove the path related to the device in the broadcast message, so that only the path related to the sub-node device is broadcast and sent. Exemplarily, during the path broadcasting process, the first network device may receive a third broadcast message, and the third broadcast message includes the main path and backup path of the first network device, and the main path and backup path of the sub-node device of the first network device. Based on the third broadcast message, the first network device may generate and send a fourth broadcast message, and the fourth broadcast message includes the main path and backup path of the sub-node device of the first network device. In this way, after receiving the fourth broadcast message, the sub-node device of the first network device can obtain the main path and backup path of the device.

[0227] In this solution, after receiving a broadcast message as a parent node device, the path information related to the device is obtained from the broadcast message, and a new broadcast message is generated based on the path information related to the child node device of the device in the broadcast message, and then the new broadcast message is continued to be sent to ensure that the child node device can obtain the path information based on the new broadcast message. Since the path information related to the parent node device is removed from the new broadcast message, the sending overhead of the broadcast message can be reduced as much as possible.

[0228] For example, see Fig.16 , Fig.16 A schematic diagram of a process of sending path information provided in an embodiment of the present application. Fig.16 As shown, after determining the primary paths and backup paths of all slave node APs, AP1 as the root node device can broadcast path information on the air interface, that is, send a broadcast message carrying the primary paths and backup paths corresponding to all slave node APs.

[0229] After receiving the broadcast message sent by AP1, AP2 and AP4, which are child nodes of AP1, first detect whether the received broadcast message comes from their own parent node. If the received broadcast message comes from their own parent node, the primary path and backup path of this node are saved based on the broadcast message. In addition, if this node also has subordinate nodes (i.e., other nodes located below the current node in the tree topology), the primary paths and backup paths corresponding to all subordinate nodes are extracted from the broadcast message, a new broadcast message is generated, and the primary paths and backup paths corresponding to all subordinate nodes are carried in the new broadcast message.

[0230] For example, after AP2 receives the broadcast message sent by AP1, because AP2 has a subordinate node AP6, AP2 extracts the main path and backup path corresponding to AP6 from the received broadcast message, and generates a new broadcast message carrying the main path and backup path corresponding to AP6, and then continues to send new broadcast messages. Similarly, after AP4 receives the broadcast message sent by AP1, because AP4 has a subordinate node AP9, AP4 extracts the main path and backup path corresponding to AP9 from the received broadcast message, and generates a new broadcast message carrying the main path and backup path corresponding to AP9, and then continues to send new broadcast messages.

[0231] The broadcast message carrying the main path and backup path of the slave node sent on the air interface can use the existing Beacon mechanism, such as carrying one or more Route Information elements in the Beacon frame to represent the path information, or use a broadcast frame similar to a Gate Announcement frame to send the path information.

[0232] In general, in a wireless mesh network, the root node device can select the appropriate primary path and backup path for each network device based on the link information of the entire wireless mesh network, and send it to each network device. In the process of sending the path, the path sending in the form of broadcast messages is suitable for the root node device to periodically refresh the primary path and backup path of the network device; the path sending in the form of unicast messages is suitable for event-triggered refresh of path information for specific network devices. Through the combination of the two path sending methods, the network devices in the wireless mesh network can always obtain the primary path and backup path between them and the root node device in real time.

[0233] After the root node device executes the distribution of path information, each network device in the wireless mesh network can obtain the main path and backup path of this device. During normal operation, the network device uses the main path to transmit data. In addition, the network device continuously monitors the link between this device and the parent node device. When the link between the network device and the parent node device fails, such as the signal strength or quality of the link between the network device and the parent node device is lower than a certain threshold, or the network device does not receive the information periodically sent by the parent node device (such as Beacon frames or other heartbeat information), the network device triggers the backup path activation mechanism, that is, the backup path is activated to replace the main path for data transmission.

[0234] For example, see Fig.17 , Fig.17 A schematic diagram of a switching backup path provided in an embodiment of the present application. Fig.17 As shown in the figure, in the wireless mesh network, the main path of AP9 is AP9<->AP4<->AP1, and the backup path is AP9<->AP2<->AP1. When AP9 detects that the link between the node and the parent node AP4 fails, it starts the backup path based on the locally stored backup path and connects to the new parent node AP2, thereby ensuring that AP9 can forward data through AP2 and avoid data transmission service interruption.

[0235] See also Fig.18 , Fig.18 A schematic diagram of a process of switching to a backup path provided in an embodiment of the present application. Fig.18 As shown, the process of switching the path from the node AP9 includes the following steps.

[0236] First, the slave node AP9 always monitors the link status between AP9 and the parent node AP4. After discovering the link failure between AP9 and AP4, AP9 triggers the re-path escape mechanism. Specifically, the slave node AP9 queries the backup path saved by the node and decides to switch to the backup path.

[0237] Then, the slave node AP9 starts the backup path and establishes a data channel with the new parent node AP2, so as to exchange data with AP2 based on the data channel.

[0238] Secondly, the slave node AP9 reports a route reset message to the master node AP1. The route reset message can reuse the existing path error (PERR) message. Optionally, when AP9 is issued multiple backup paths, AP9 can also add a route information element field in the route reset message to identify which backup path is started by the slave node AP9.

[0239] Optionally, after receiving the routing reset message from AP9, the master node AP1 will calculate a new path after removing the link AP4<->AP9, and send the new path to each affected node. The new path may include a new main path and a backup path. The specific process of the master node AP1 sending the new path is as described in the previous embodiment, and will not be repeated here.

[0240] Please refer to the following Table 2, which is used to show the changes in the addresses attached to data packets sent in the new and old data channels before and after the AP9 enables the backup path.

[0241] Address 1 Address 2 Address 3 Address 4 Before enabling the backup path <![CDATA[MAC AP4 ]]> <![CDATA[MAC AP9 ]]> <![CDATA[MAC STA2 ]]> <![CDATA[MAC STA1 ]]> After enabling the alternate path <![CDATA[MAC AP2 ]]> <![CDATA[MAC AP9 ]]> <![CDATA[MAC STA2 ]]> <![CDATA[MAC STA1 ]]>

[0242] Among them, Table 2 corresponds to Fig.17 In the wireless mesh network shown in the figure, the node STA1 under AP9 sends a data packet to the node STA2 under AP8. The data packet sent by AP9 should include 4 addresses before and after the backup path is enabled. The meanings of these 4 addresses are:

[0243] Address 1: The receiver address of this hop link, that is, the parent node address of AP9. Before the backup path is enabled, address 1 is the MAC address of AP4. After the backup path is enabled, address 1 is changed to the MAC address of AP2.

[0244] Address 2: The sender address of this hop link, that is, the address of AP9 itself.

[0245] Address 3: The receiver address of the original data, that is, the address of STA2.

[0246] Address 4: The sender address of the original data, that is, the address of STA1.

[0247] That is to say, after the backup path is enabled, AP9 changes the address 1 in the data packet sent from the air interface from the MAC address of AP4 to the MAC address of AP2, thereby establishing a data channel to the new parent node AP2 and completing the path escape.

[0248] Optionally, the slave node may also report its neighbor link information when reporting the path reset information to the master node, such as carrying a Neighbor Link Report element field in the PERR, so that the master node can better determine the new path.

[0249] In general, after triggering link reselection, the slave node omits the traditional link search process and directly enables the backup link to connect to the new parent node. This not only avoids the delay caused by link search, but also avoids the slave node selecting the wrong node and avoids the problem of service interruption caused by failure to restore connectivity with the original wireless mesh network.

[0250] The above embodiments introduce that after a network device in a wireless mesh network finds a link failure, it enables a backup path and reconnects to a root node device in the wireless mesh network through a new link. However, in some embodiments, root node devices in different wireless mesh networks connected through a distributed system DS (Distributed System) can exchange network topology information and link information in the wireless mesh network with each other, so that a network device in a wireless mesh network can access another wireless mesh network when the root node device connected to it fails, thereby connecting to a root node device in another wireless mesh network, thereby avoiding interruption of data services that the network device is responsible for.

[0251] For example, see Fig.19A , Fig.19A A schematic diagram of a node in a wireless mesh network switching path and connecting to another wireless mesh network provided in an embodiment of the present application. Fig.19A As shown, AP1-AP6 belong to the same wireless mesh network (i.e. Fig.19A AP7-AP11 belongs to another wireless mesh network (i.e. Fig.19A In addition, AP1 and AP11 are both root nodes in the wireless mesh network, and AP1 and AP11 are connected by wire. During the normal operation of the two wireless mesh networks, AP1 and AP11 as root nodes can exchange network topology information and link information between nodes in each other's wireless mesh networks. In this way, AP1 and AP11 can actually clearly know the link information between nodes in the two wireless mesh networks. Then, if AP7 only has a link to AP11 in WMN2, in the path delivery stage, AP11 can deliver a backup path with the parent node being AP6 to AP7, so that AP7 can access the wireless mesh network where AP1 is located based on the backup path.

[0252] In the event of a failure of AP11, AP7 will detect that the link between AP7 and AP11 has failed, so AP7 can enable the backup path whose parent node is AP6 to connect to AP6, and finally connect to the root node AP1 in another wireless mesh network through AP6 and AP4, thereby maximizing the connectivity of the network.

[0253] In some other embodiments, when multiple network devices in a wireless mesh network report link information to a designated device, the link information reported by the multiple network devices may have other uses in addition to being used to generate a primary path and a backup path for each network device.

[0254] For example, see Fig.19B , Fig.19B A schematic diagram of a network management system monitoring the link status in a wireless mesh network provided in an embodiment of the present application. Fig.19B As shown, the wireless mesh network includes AP1-AP9, where AP1 is a master node connected to the network management system through a wired network, and AP2-AP9 are slave nodes. During the operation of the wireless mesh network, all APs in the wireless mesh network measure the link status between themselves and neighboring nodes, and all slave nodes report the measured link status (i.e., the link status between the slave node and the neighboring node) to AP1. Then, AP1 actively or in response to the request of the network management system, sends the link status measured by all APs (including itself) in the entire wireless mesh network to the network management system.

[0255] In this way, the network management system can obtain the link status between APs in the entire wireless mesh network, thereby realizing the monitoring of the link status of the APs. For example, the network management system can also display the obtained link status between APs to the user, so that the user can monitor the link between APs according to actual needs.

[0256] For example, see Fig.19C , Fig.19C A schematic diagram of implementing load sharing based on link status in a wireless mesh network provided in an embodiment of the present application. Fig.19C As shown, the wireless mesh network includes AP1-AP9, where AP1 is a master node connected to the external network through a wired network, and AP2-AP9 are slave nodes. In addition, STA1 is connected to AP1, STA4 is connected to AP4, and STA9 is connected to AP9. During the operation of the wireless mesh network, all APs in the wireless mesh network measure the link status between themselves and neighboring nodes, and all slave nodes report the measured link status to AP1.

[0257] After AP1 obtains the link status between APs in the wireless mesh network, AP1 selects a primary path (AP1<->AP4<->AP9) and a backup path (AP1<->AP2<->AP9) for slave node AP9, where the link quality of the primary path is slightly better than that of the backup path.

[0258] When STA1 has a large amount of data to transmit to STA4 and STA9, STA1 first transmits the data to AP1. Since the main path from AP1 to AP9 includes the link between AP1 and AP4, and this link also needs to transmit the data sent by STA1 to STA4. Therefore, in order to avoid congestion in the link between AP1 and AP4, AP1 can adopt the following data transmission strategy:

[0259] 1. All data sent from STA1 to STA4 is forwarded through the link between AP1 and AP4;

[0260] 2. Part of the data sent from STA1 to STA9 is forwarded through the primary path of AP9, that is, through the link between AP1 and AP4; the other part is forwarded through the backup path of AP9, that is, through the link between AP1 and AP2;

[0261] In this way, by using the primary path and the backup path for data forwarding at the same time, link congestion can be avoided and the communication rate can be improved.

[0262] The above embodiments introduce the communication recovery method for link failure provided in the embodiments of the present application. The following will introduce the device for executing the communication recovery method for link failure.

[0263] See also Fig. 20 , Fig. 20 A schematic diagram of the structure of a network device provided in an embodiment of the present application. Fig. 20 As shown, the network device provided in the embodiment of the present application is a slave node device in a wireless mesh network, and the network device includes:

[0264] The measurement module 2001 is used to measure the link status between the first network device and the neighboring device;

[0265] A sending module 2002 is used to send first link information to a second network device, where the second network device is a root node device in a wireless mesh network, and the first link information is used to indicate a link state between the first network device and a neighboring device;

[0266] A receiving module 2003 is used to receive a primary path and a backup path from a second network device, where both the primary path and the backup path are used to indicate a path for the first network device to forward data, where the primary path includes a link between the first network device and a first neighboring device, and the backup path includes a link between the first network device and a second neighboring device;

[0267] The sending module 2002 is also used to forward data through the backup path when a link in the primary path fails.

[0268] In a possible implementation, the sending module 2002 is further configured to send a first broadcast message, where the first broadcast message includes first link information.

[0269] In one possible implementation, the second network device is a root node device in a tree topology constructed based on a wireless mesh network. When the first network device has a child node device, the receiving module 2003 is also used to receive the second link information sent by the child node device, and the second link information is used to indicate the link status between the child node device and a neighbor device of the child node device; the sending module 2002 is also used to forward the second link information to the second network device.

[0270] In a possible implementation manner, the first broadcast message includes a Beacon frame, and the first link information is carried in an extension field or a Vendor Specific field in the Beacon frame.

[0271] In a possible implementation, the sending module 2002 is further configured to send a first unicast message to the second network device, where the first unicast message includes the first link information.

[0272] In a possible implementation manner, the first unicast message includes an extended management frame, and the first link information is carried in the extended management frame;

[0273] Alternatively, the first unicast message includes a PREQ frame, and the first link information is carried in the PREQ frame.

[0274] In a possible implementation manner, the first link information includes an identifier of the first network device, the number of neighbor devices, identifiers of the neighbor devices, and link quality metrics between the first network device and the neighbor devices.

[0275] In one possible implementation, the second network device is a root node device in a tree topology constructed based on a wireless mesh network, and the receiving module 2003 is also used to receive the second link information sent by the child node device, and the second link information is used to indicate the link status between the child node device and the neighboring device of the child node device; the sending module 2002 is also used to forward the second link information to the second network device.

[0276] In a possible implementation, the sending module 2002 is further configured to send a second broadcast message to the second network device, where the second broadcast message includes the first link information and the second link information.

[0277] In one possible implementation, the receiving module 2003 is also used to receive a third broadcast message, which includes the main path and backup path of the first network device, and the main path and backup path of the sub-node device of the first network device; the sending module 2002 is also used to send a fourth broadcast message, which includes the main path and backup path of the sub-node device of the first network device.

[0278] In a possible implementation, the third broadcast message includes a second Beacon frame, and the primary path and the backup path are carried in an extended field or a Vendor Specific field in the second Beacon frame.

[0279] In a possible implementation, the receiving module 2003 is further configured to receive a second unicast message, where the second unicast message includes a primary path and a backup path of the first network device.

[0280] In a possible implementation, the second unicast message includes an extended management frame, and the primary path and the backup path of the first network device are carried in the extended management frame;

[0281] Alternatively, the second unicast message includes a path response frame, and the primary path and the backup path of the first network device are carried in the path response frame.

[0282] In a possible implementation, the sending module 2002 is further configured to send a routing reset message to the second network device through the backup path after a link failure in the primary path occurs, where the routing reset message is used to indicate a link failure in the primary path.

[0283] See also Fig.21 , Fig.21 A schematic diagram of the structure of a network device provided in an embodiment of the present application. Fig.21 As shown, the network device provided in the embodiment of the present application is a master node device in a wireless mesh network, and the network device includes:

[0284] The receiving module 2101 is used to receive a plurality of link information, where the plurality of link information comes from a plurality of network devices in the wireless mesh network, and the plurality of link information is used to indicate the link status between different network devices and neighboring devices respectively;

[0285] A processing module 2102 is configured to determine a primary path and a backup path of a first network device based on multiple link information, wherein the multiple network devices include the first network device, the primary path and the backup path are both used to indicate a path for the first network device to forward data, the primary path includes a link between the first network device and a first neighboring device, and the backup path includes a link between the first network device and a second neighboring device;

[0286] The sending module 2103 is used to send the primary path and the backup path to the first network device, where the backup path is used to be enabled when a link in the primary path fails.

[0287] In one possible implementation, the receiving module 2101 is also used to receive a first broadcast message from a first network device, the first broadcast message including first link information, the first link information being used to indicate a link status between the first network device and a neighboring device, and link information between a child node device of the first network device and a neighboring device.

[0288] In a possible implementation manner, the first broadcast message includes a Beacon frame, and the first link information is carried in an extension field or a Vendor Specific field in the Beacon frame.

[0289] In a possible implementation, the receiving module 2101 is further used to receive a first unicast message sent by a child node device, where the first unicast message includes first link information, and the first link information is used to indicate a link status between the first network device and a neighboring device.

[0290] In a possible implementation manner, the first unicast message includes an extended management frame, and the first link information is carried in the extended management frame;

[0291] Alternatively, the first unicast message includes a PREP frame, and the first link information is carried in the PREP frame.

[0292] In a possible implementation, the sending module 2103 is further configured to send a second broadcast message, where the second broadcast message includes a primary path and a backup path;

[0293] Alternatively, the sending module 2103 is further configured to send a second unicast message, where the second unicast message includes a primary path and a backup path.

[0294] In a possible implementation manner, the second broadcast message includes a second Beacon frame, and the primary path and the backup path are carried in an extended field or a Vendor Specific field in the second Beacon frame.

[0295] In a possible implementation, the second unicast message includes an extended management frame, and the primary path and the backup path are carried in the extended management frame;

[0296] Alternatively, the second unicast message includes a PREP frame, and the primary path and the backup path are carried in the PREP frame.

[0297] In a possible implementation manner, the first link information includes an identifier of the first network device, the number of neighbor devices, identifiers of the neighbor devices, and link quality metrics between the first network device and the neighbor devices.

[0298] In a possible implementation manner, the primary path and the backup path include at least one of the following: path priority, path hop count, and identification of a network device that the path passes through.

[0299] In a possible implementation, the sending module 2103 is further configured to send a routing broadcast message, where the routing broadcast message includes a primary path and a backup path of each network device in the plurality of network devices.

[0300] In one possible implementation, the receiving module 2101 is further used to receive a routing reset message from the first network device, where the routing reset message is used to indicate a link failure in the primary path; the processing module 2102 is further used to determine a new primary path and a new backup path corresponding to the first network device based on the routing reset message; and the sending module 2103 is further used to send the new primary path and the new backup path to the first network device.

[0301] Next, a network device provided by an embodiment of the present application is introduced. Fig. 22 , Fig. 22 A schematic diagram of a network device provided in an embodiment of the present application, the network device 2200 can be specifically an optical modem or a router, etc., which is not limited here. Specifically, the network device 2200 includes: a receiver 2201, a transmitter 2202, a processor 2203 and a memory 2204 (wherein the number of processors 2203 in the network device 2200 can be one or more, Fig. 22 In the example of FIG. 2 , a processor 2203 may include an application processor 22031 and a communication processor 22032. In some embodiments of the present application, the receiver 2201, the transmitter 2202, the processor 2203 and the memory 2204 may be connected via a bus or other means.

[0302] The memory 2204 may include a read-only memory and a random access memory, and provides instructions and data to the processor 2203. A portion of the memory 2204 may also include a non-volatile random access memory (NVRAM). The memory 2204 stores processor and operation instructions, executable modules or data structures, or subsets thereof, or extended sets thereof, wherein the operation instructions may include various operation instructions for implementing various operations.

[0303] The processor 2203 controls the operation of the network device. In a specific application, the various components of the network device are coupled together through a bus system, wherein the bus system includes not only a data bus but also a power bus, a control bus, and a status signal bus, etc. However, for the sake of clarity, various buses are referred to as bus systems in the figure.

[0304] The method disclosed in the above embodiment of the present application can be applied to the processor 2203, or implemented by the processor 2203. The processor 2203 can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the processor 2203. The above processor 2203 can be a general processor, a digital signal processor (digital signal processing, DSP), a microprocessor or a microcontroller, and can further include an application specific integrated circuit (application specific integrated circuit, ASIC), a field programmable gate array (field-programmable gate array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The processor 2203 can implement or execute the various methods, steps and logic block diagrams disclosed in the embodiments of the present application. The general processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor to execute, or the hardware and software modules in the decoding processor are combined to execute. The software module can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 2204, and the processor 2203 reads the information in the memory 2204 and completes the steps of the above method in combination with its hardware.

[0305] The receiver 2201 can be used to receive input digital or character information, and generate signal input related to the relevant settings and function control of the network device. The transmitter 2202 can be used to output digital or character information through the first interface; the transmitter 2202 can also be used to send instructions to the disk group through the first interface to modify the data in the disk group; the transmitter 2202 can also include a display device such as a display screen.

[0306] In one embodiment of the present application, the processor 2203 is configured to execute Figure 5 The method in the corresponding embodiment.

[0307] The network device provided in the embodiment of the present application may specifically be a chip, and the chip includes: a processing unit and a communication unit, wherein the processing unit may be, for example, a processor, and the communication unit may be, for example, an input / output interface, a pin or a circuit, etc. The processing unit may execute computer-executable instructions stored in the storage unit so that the chip in the network device executes the rendering method described in the above embodiment. Optionally, the storage unit is a storage unit in the chip, such as a register, a cache, etc. The storage unit may also be a storage unit located outside the chip in the wireless access device end, such as a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM), etc.

[0308] See also Fig.23 , Fig.23 This is a schematic diagram of the structure of a computer-readable storage medium provided in an embodiment of the present application. The present application also provides a computer-readable storage medium. In some embodiments, the above Figure 5 The disclosed methods may be implemented as computer program instructions encoded in a machine-readable format on a computer-readable storage medium or on other non-transitory media or articles of manufacture.

[0309] Fig.23 Schematically illustrates a conceptual partial view of an example computer-readable storage medium including a computer program for executing a computer process on a computing device, arranged in accordance with at least some embodiments presented herein.

[0310] In one embodiment, the computer readable storage medium 2300 is provided using a signal bearing medium 2301. The signal bearing medium 2301 may include one or more program instructions 2302, which when executed by one or more processors may provide the above-mentioned Figure 5 The functions or parts of the functions described. In addition, Fig.23 Program instructions 2302 in also describe example instructions.

[0311] In some examples, the signal bearing medium 2301 may include a computer readable medium 2303 such as, but not limited to, a hard drive, a compact disk (CD), a digital video disk (DVD), a digital tape, a memory, a ROM or RAM, and the like.

[0312] In some embodiments, the signal bearing medium 2301 may include a computer recordable medium 2304, such as, but not limited to, a memory, a read / write (R / W) CD, a R / W DVD, etc. In some embodiments, the signal bearing medium 2301 may include a communication medium 2305, such as, but not limited to, a digital and / or analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communication link, a wireless communication link, etc.). Thus, for example, the signal bearing medium 2301 may be communicated by a wireless form of the communication medium 2305 (e.g., a wireless communication medium complying with the IEEE 802 standard or other transmission protocol).

[0313] The one or more program instructions 2302 may be, for example, computer executable instructions or logic implementation instructions. In some examples, the computing device of the computing device may be configured to provide various operations, functions, or actions in response to the program instructions 2302 communicated to the computing device via one or more of the computer readable medium 2303, the computer recordable medium 2304, and / or the communication medium 2305.

[0314] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments may be implemented in the form of a computer program product.

[0315] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website site, a computer, a server, or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server, or data center. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a server or a data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive Solid State Disk (SSD)), etc.

[0316] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0317] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0318] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0319] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0320] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), disk or optical disk and other media that can store program codes.

[0321] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A communication recovery method for link failure, characterized in that: The method is applied to a first network device in a wireless mesh network, and the method comprises: The first network device sends first link information to the second network device, where the first link information is used to indicate a link state between the first network device and a neighboring device; The first network device receives a primary path and a backup path from the second network device, where both the primary path and the backup path are used to indicate a path for the first network device to forward data, the primary path includes a link between the first network device and a first neighboring device, and the backup path includes a link between the first network device and a second neighboring device; When a link in the primary path fails, the first network device forwards data through the backup path.

2. The method according to claim 1, characterized in that The first network device sending the first link information to the second network device includes: The first network device sends a first broadcast message, where the first broadcast message includes the first link information; Alternatively, the first network device sends a first unicast message, where the first unicast message includes the first link information.

3. The method according to claim 1 or 2, characterized in that: The second network device is a root node device in a tree topology constructed based on the wireless mesh network. In the case where the first network device has a child node device, the method further includes: The first network device receives second link information sent by the child node device, where the second link information is used to indicate a link state between the child node device and a neighboring device of the child node device; The first network device sends a second broadcast message, where the second broadcast message includes the first link information and the second link information.

4. The method according to claim 2, characterized in that: The first broadcast message includes a first beacon frame, and the first link information is carried in an extended field or a vendor-specific field in the first Beacon frame.

5. The method according to claim 2, characterized in that: The first unicast message includes an extended management frame, and the first link information is carried in the extended management frame; Alternatively, the first unicast message includes a path request PREQ frame, and the first link information is carried in the PREQ frame.

6. The method according to any one of claims 1 to 5, characterized in that: The first link information includes an identifier of the first network device, the number of neighbor devices of the first network device, identifiers of neighbor devices, and link quality metrics between the first network device and the neighbor devices.

7. The method according to any one of claims 1 to 6, characterized in that: The first network device periodically sends the first link information to the second network device; Alternatively, when the link status between the first network device and a neighboring device changes, the first network device sends the first link information to the second network device.

8. The method according to any one of claims 1 to 7, characterized in that: The first network device receives the primary path and the backup path from the second network device, including: The first network device receives a third broadcast message, wherein the third broadcast message includes a primary path and a backup path of the first network device; Alternatively, the first network device receives a second unicast message, where the second unicast message includes the primary path and the backup path of the first network device.

9. The method according to claim 8, characterized in that The second network device is a root node device in a tree topology constructed based on the wireless mesh network, and in the case where the first network device has a child node device, the third broadcast message further includes a primary path and a backup path of the child node device of the first network device; The method further includes: the first network device sending a fourth broadcast message, wherein the fourth broadcast message includes a primary path and a backup path of a sub-node device of the first network device.

10. The method according to claim 8 or 9, characterized in that: The third broadcast message includes a second beacon frame, and the primary path and the backup path are carried in an extension field or a VendorSpecific field in the second Beacon frame.

11. The method according to claim 8, characterized in that The second unicast message includes an extended management frame, and the primary path and the backup path of the first network device are carried in the extended management frame; Alternatively, the second unicast message includes a path reply PREP frame, and the primary path and the backup path of the first network device are carried in the PREP frame.

12. The method according to any one of claims 1 to 11, characterized in that: The primary path and the backup path include at least one of the following: path priority, path hop count, and identification of network devices that the path passes through.

13. The method according to any one of claims 1 to 12, characterized in that: The method further comprises: The first network device measures a link status between the first network device and a neighboring device, and generates the first link information based on the measured link status.

14. The method according to any one of claims 1 to 13, characterized in that: The method further comprises: After a link failure in the primary path, the first network device sends a routing reset message to the second network device through the backup path, where the routing reset message is used to indicate the link failure in the primary path.

15. A communication recovery method for link failure, characterized in that: The method comprises: The second network device receives a plurality of link information, where the plurality of link information comes from a plurality of network devices in the wireless mesh network, and the plurality of link information is used to indicate link status between different network devices and neighboring devices respectively; The second network device determines a primary path and a backup path of the first network device based on the multiple link information, wherein the multiple network devices include the first network device, the primary path and the backup path are both used to indicate a path for the first network device to forward data, the primary path includes a link between the first network device and a first neighboring device, and the backup path includes a link between the first network device and a second neighboring device; The second network device sends the primary path and the backup path to the first network device, where the backup path is used to be enabled when a link in the primary path fails.

16. The method according to claim 15, characterized in that The second network device receives a plurality of link information, including: The second network device receives a first broadcast message from the first network device, where the first broadcast message includes first link information, where the first link information is used to indicate the link status between the first network device and a neighboring device, and / or link information between a sub-node device of the first network device and a neighboring device.

17. The method according to claim 16, characterized in that The first broadcast message includes a first Beacon frame, and the first link information is carried in an extension field or a Vendor Specific field in the first Beacon frame.

18. The method according to claim 15, characterized in that The second network device receives a plurality of link information, including: The second network device receives a first unicast message sent by a child node device, where the first unicast message includes first link information, where the first link information is used to indicate a link state between the first network device and a neighboring device; The first unicast message includes an extended management frame, and the first link information is carried in the extended management frame; Alternatively, the first unicast message includes a PREQ frame, and the first link information is carried in the PREQ frame.

19. The method according to any one of claims 15 to 18, characterized in that: The primary path and the backup path include at least one of the following: path priority, path hop count, and identification of network devices that the path passes through.

20. The method according to any one of claims 15 to 19, characterized in that: The second network device sending the primary path and the backup path to the first network device includes: The second network device sends a second broadcast message, where the second broadcast message includes the primary path and the backup path; Alternatively, the second network device sends a second unicast message, where the second unicast message includes the primary path and the backup path.

21. The method according to claim 20, characterized in that The second broadcast message includes a second beacon frame, and the primary path and the backup path are carried in an extension field or a VendorSpecific field in the second Beacon frame.

22. The method according to claim 20, characterized in that The second unicast message includes an extended management frame, and the primary path and the backup path are carried in the extended management frame; Alternatively, the second unicast message includes a PREP frame, and the primary path and the backup path are carried in the PREP frame.

23. The method according to any one of claims 15 to 22, characterized in that: The first link information includes an identifier of the first network device, the number of neighbor devices, an identifier of the neighbor device, and a link quality metric value between the first network device and the neighbor device.

24. The method according to any one of claims 15 to 23, characterized in that: The method further comprises: The second network device receives a routing reset message from the first network device, where the routing reset message is used to indicate a link failure in the primary path; The second network device determines a new primary path and a new backup path corresponding to the first network device based on the route reset message; The second network device sends the new primary path and the new backup path to the first network device.

25. A network device, characterized in that: The network device is a device in a wireless mesh network, and the network device includes: A sending module, used to send first link information to a second network device, where the first link information is used to indicate a link state between the first network device and at least one neighboring device; a receiving module, configured to receive a primary path and a backup path from the second network device, wherein the primary path and the backup path are both used to indicate a path for the first network device to forward data, the primary path includes a link between the first network device and a first neighboring device, and the backup path includes a link between the first network device and a second neighboring device; The sending module is further configured to forward data via the backup path when a link failure occurs in the primary path.

26. A network device, characterized in that: The network equipment includes: A receiving module, used to receive multiple link information, where the multiple link information comes from multiple network devices in the wireless mesh network, and the multiple link information is used to indicate the link status between different network devices and neighboring devices respectively; a processing module, configured to determine a primary path and a backup path of a first network device based on the plurality of link information, wherein the plurality of network devices include the first network device, the primary path and the backup path are both used to indicate a path for the first network device to forward data, the primary path includes a link between the first network device and a first neighboring device, and the backup path includes a link between the first network device and a second neighboring device; A sending module is used to send the main path and the backup path to the first network device, and the backup path is used to be enabled when a link in the main path fails.

27. A network device, characterized in that: The device comprises a memory and a processor; the memory stores codes, the processor is configured to execute the codes, and when the codes are executed, the device executes the method according to any one of claims 1 to 24.

28. A communication system, characterized in that: Includes the network device as described in claim 25 and the network device as described in claim 26.

29. A computer storage medium, characterized in that The computer storage medium stores instructions, which, when executed by a computer, cause the computer to implement the method of any one of claims 1 to 24.

30. A computer program product, characterized in that The computer program product stores instructions, which, when executed by a computer, cause the computer to implement the method according to any one of claims 1 to 24.

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