CN119653397A

CN119653397A - A communication recovery method and related device for link failure

Info

Publication number: CN119653397A
Application number: CN202311197262.7A
Authority: CN
Inventors: 杨登峰; 彭炎
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2023-09-15
Filing date: 2023-09-15
Publication date: 2025-03-18

Abstract

A communication recovery method for link failure is applied to network devices in a wireless mesh network. In this method, the network device in the wireless mesh network first detects the link status between the network 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 a main path and a 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 that the business can be carried out normally when the link between the network devices changes.

Description

Communication recovery method and related device for link failure

Technical Field

The present application relates to the field of communications technologies, and in particular, to a method and an apparatus for recovering communications of a link failure.

Background

A wireless mesh (mesh) network is a multi-hop wireless network, which is the biggest difference from a conventional single-hop wireless network in that a plurality of Access Points (APs) are connected using wireless links instead of wired links. The APs in the wireless mesh network not only provide a user access function, but also forward data on a wireless link, so that the data is routed from one AP to another AP, and finally the wireless mesh network is formed by accessing a wired network through a portal (portal) node.

The wireless mesh network removes wiring requirements among APs, and is more flexible to install and deploy. In the wireless mesh network, if new node equipment is to be added, configuration can be automatically carried out by simply connecting a power supply, and an optimal multi-hop transmission path is determined. Compared with the traditional wireless local area network (Wireless Local Area Network, WLAN), the wireless mesh network can remarkably reduce the deployment cost and provide greater convenience and expansibility. Therefore, the wireless mesh network is widely applied to the scenes of inconvenient wiring or high wiring cost such as large warehouses, ports and terminals, mine roadways, emergency communication and the like besides being applied to the common scenes of the traditional WLAN such as enterprise networks, office networks, campus networks and the like.

However, the related standard of the wireless mesh network is mainly focused on solving the problem of network connectivity under the condition of using wireless connection between APs, and does not pay attention to the situation that the wireless link between APs possibly moves in the using process to cause severe change of a wireless channel, so that the situation of data packet loss and even service interruption of the wireless mesh network can occur in some scenes to influence the normal operation of the service.

Disclosure of Invention

The application provides a communication recovery method for link failure, which can quickly recover communication under the condition that the link fails and ensure normal operation of service.

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, a first network device measuring a link state between the first network device and a neighbor device. The first network device is any device except a root node device in a tree topology constructed based on a wireless mesh network, for example, a router, a wireless switch or a wireless transceiver and other physical devices.

After the link state is measured, the first network device sends first link information to the second network device, wherein the first link information is used for indicating the link state between the first network device and the neighbor device. Specifically, the first link information is actually used to indicate a link state between the first network device and each of the plurality of neighbor devices, for example, a link state between the first network device and the first neighbor device, and a link state between the first network device and the second neighbor device. The second network device is a designated device in the wireless mesh network, and is configured to receive link information reported by other network devices in the wireless mesh network, and further issue a corresponding main path and a corresponding standby path for each network device based on the obtained link information.

And secondly, the first network device receives a main path and a standby path from the second network device, wherein the main path and the standby path are used for indicating paths for forwarding data by the first network device, the main path comprises a link between the first network device and the first neighbor device, and the standby path comprises 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.

Finally, the first network device forwards the data over the backup path upon failure of the link in the primary path.

In the scheme, the network equipment in the wireless mesh network detects the link state between the network equipment and the neighbor equipment, and reports the link state between the network equipment and the neighbor equipment to the designated equipment of the wireless mesh network, so that the designated equipment can issue a main path and a standby path for transmitting data to the designated network equipment for each other network equipment according to the link state between the network equipment in the whole wireless mesh network. 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 pre-issued standby path 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 fails.

In one possible implementation, the first network device sends first link information to the second network device, and specifically includes the first network device sending a first broadcast message, where the first broadcast message includes the first link information.

In one possible implementation manner, the second network device is a root node device in a tree topology constructed based on the wireless mesh network, for example, the second network device is a boundary device between the external network and the wireless mesh network, and is responsible for providing a function of accessing the external network for the network device in the wireless mesh network. In the case that the first network device has the child node device, the first network device may receive 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, and forward the second link information to the second network device.

In the scheme, under the condition that the first network equipment is provided with the child node equipment, the first network equipment is used for assisting the child node equipment to forward the link information from the child node equipment to the root node equipment by utilizing the data transfer characteristic of the wireless mesh network, so that the link information measured by all network equipment in the wireless mesh network can be effectively reported to the root node equipment.

In one possible implementation, the first network device sending first link information to the second network device includes the first network device sending a second broadcast message to the second network device, the second broadcast message including 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 child node device through one broadcast message, so that the message overhead is reduced, and the transmission efficiency of the link information is improved.

In one possible implementation, the first broadcast message includes a first Beacon (Beacon) frame, and the first link information is carried in an extension field or a Vendor Specific (Vendor Specific) field in the first Beacon frame.

In the scheme, the link information measured by the network equipment is carried in the existing broadcast message of the wireless mesh network, so that the link state can be reported to the root node equipment, the change of the prior art is reduced, and the feasibility of the scheme is improved.

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

In the scheme, the unicast message is sent to the root node equipment by the first network equipment, so that the link information can be directionally transmitted to the root node equipment, and the root node equipment can be ensured to accurately receive the link information from the first network equipment.

In one possible implementation, the first unicast message includes an extended management frame, and the first link information is carried in the extended management frame;

or the first unicast message includes a path request PREQ frame, and the first link information is carried in the PREQ frame.

In the scheme, the carrying of the link information is realized on the basis of the existing data frame, the reporting of the link state to the root node equipment can be realized, the modification of the prior art is reduced, and the realizability of the scheme is improved.

In one 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.

Or the first network device sends the first link information to the second network device when the link state between the first network device and the neighbor device changes.

In general, the link state reporting is performed by using a broadcast message, which is suitable for periodically reporting the neighbor link state from the node (i.e., the first network device), and the link state reporting is performed by using a unicast message, which is suitable for reporting the neighbor link state from the node after the event triggering. The combination of the two different reporting modes enables the master node to master the link quality of each node in the whole network in real time.

In one possible implementation, the first link information includes an identification of the first network device, a number of neighbor devices, an identification of the neighbor devices, and a link quality metric value between the first network device and the neighbor devices.

In one possible implementation, the first network device receiving the primary path and the backup path from the second network device includes the first network device receiving a third broadcast message including the primary path and the backup path of the first network device.

In one possible implementation manner, the second network device is a root node device in a tree topology constructed based on the wireless mesh network, and the third broadcast message further comprises a main path and a standby path of the child node device of the first network device in the case that the first network device has the child node device, and the first network device sends a fourth broadcast message, wherein the fourth broadcast message comprises the main path and the standby path of the child node device of the first network device.

In the scheme, after the father node equipment receives the broadcast message, path information related to the equipment is obtained from the broadcast message, a new broadcast message is generated based on the path information related to the child node equipment of the equipment in the broadcast message, and further the new broadcast message is continuously sent, so that the child node equipment can obtain the path information based on the new broadcast message. Since path information about the parent node device is removed from the new broadcast message, transmission overhead of the broadcast message can be reduced as much as possible.

In one possible implementation, 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 Vendor Specific field in the second Beacon frame.

In one possible implementation, a first network device receives a second unicast message from a second network device, the second unicast message including a primary path and a backup path of the first network device.

In one possible implementation, the primary path and the backup path include at least one of a path priority, a path hop count, and an identification of a network device through which the path passes.

In one possible implementation, after the link failure in the primary path, the first network device may also send a route reset message to the second network device over the backup path, the route reset message being used to indicate the link failure in the primary path.

That is, the route reset message is equivalent to be used to notify the second network device that the main path used on the first network device is faulty, so that the second network device can plan a new path for the first network device, so that the subsequent second network device can issue a new path more suitable for the first network device.

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 that first, the second network device receives a plurality of link information, the plurality of link information is from a plurality of network devices in the wireless mesh network, and the plurality of link information is respectively used for indicating link states between different network devices and neighbor devices. Since each network device except the second network device in the wireless mesh network performs a process of measuring a link state with the neighbor device and transmits link information indicating a link state between itself and the neighbor device to the second network device, the second network device can receive a plurality of link information. And the plurality of link information received by the second network device are from different network devices in the wireless mesh network, and each link information is used for indicating the link state between the network device generating the link information and the neighbor device.

The second network device then determines a primary path and a backup path for the first network device based on the plurality of link information, wherein the plurality of network devices includes the first network device, the primary path and the backup path each being for indicating a path for the first network device to forward data, the primary path including a link between the first network device and a first neighbor device, and the backup path including a link between the first network device and a second neighbor device.

Second, the second network device sends a primary path and a backup path to the first network device, the backup path for enabling upon a link failure in the primary path.

In one possible implementation, the second network device receives a plurality of link information including the second network device receiving a first broadcast message from the first network device, the first broadcast message including first link information indicating a link state between the first network device and a neighbor device. In case the first network device has a child node device, the first link information is further used to indicate link information between the child node device and a neighbor device of the first network device.

In one possible implementation, 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.

In one possible implementation, the second network device receives a plurality of link information including the second network device receiving a first unicast message sent by the first network device, the first unicast message including first link information indicating a link state between the first network device and a neighbor device.

or the first unicast message includes a PREP frame, and the first link information is carried in the PREP frame.

In one possible implementation, the second network device sends a primary path and a backup path to the first network device, including:

The second network device sends a second broadcast message, wherein the second broadcast message comprises a main path and a standby path;

or the second network device sends a second unicast message comprising the primary path and the backup path.

In one possible implementation, 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 Vendor Specific field in the second Beacon frame.

In one 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;

Or the second unicast message includes a PREP frame, with the primary path and the backup path carried in the PREP frame.

In one possible implementation, the second network device sending the primary path and the backup path to the first network device includes the second network device sending a routing broadcast message including the primary path and the backup path for each of the plurality of network devices.

In one possible implementation, the method further includes the second network device receiving a route reset message from the first network device, the route reset message indicating a link failure in the primary path, the second network device determining a new primary path and a new backup path corresponding to the first network device based on the route reset message, and the second network device sending the new primary path and the new backup path to the first network device.

A third aspect of the present application provides a network device, which is a device in a wireless mesh network, including:

the wireless mesh network comprises a sending module, a first link information sending module and a second link information sending module, wherein the sending module is used for sending first link information to second network equipment, and the first link information of the wireless mesh network is used for indicating link states between the first network equipment and a plurality of neighbor equipment;

The receiving module is used for receiving a main path and a standby path from the second network equipment, wherein the main path and the standby path are used for indicating paths for forwarding data by the first network equipment, the main path comprises a link between the first network equipment and the first neighbor equipment, and the standby path comprises a link between the first network equipment and the second neighbor equipment;

And the sending module is also used for forwarding data through the standby path when the link in the main path fails.

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

In one possible implementation manner, the second network device is a root node device in a tree topology constructed based on the wireless mesh network, and the receiving module is further configured to receive 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, and the sending module is further configured to forward the second link information to the second network device.

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

In one 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.

or the first unicast message includes a PREQ frame, and the first link information is carried in the PREQ frame.

In one possible implementation, the network device further includes:

And the measurement module is used for measuring the link states between the plurality of neighbor devices and generating the first link information based on the measured link states.

In one 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.

In one possible implementation, the third broadcast message further includes a primary path and a backup path of the child node device of the first network device, and the sending module is further configured to send a fourth broadcast message, where the fourth broadcast message includes the primary path and the backup path of the child node device of the first network device.

In one possible implementation manner, the second network device is a root node device in a tree topology constructed based on the wireless mesh network, and the third broadcast message further includes a main path and a standby path of a child node device of the first network device in the case that the first network device has the child node device;

and the sending module is further used for sending a fourth broadcast message, and the fourth broadcast message comprises a main path and a standby path of the child node equipment of the first network equipment.

In one 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.

In one 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;

Or the second unicast message includes a path reply frame in which the primary path and the backup path of the first network device are carried. In one possible implementation, the sending module is further configured to send, after the link failure in the primary path, a route reset message to the second network device through the backup path, where the route reset message is used to indicate the link failure in the primary path.

A fourth aspect of the present application provides a network device comprising:

the receiving module is used for receiving a plurality of link information, wherein the plurality of link information is from a plurality of network devices in the wireless mesh network, and the plurality of link information is respectively used for indicating the link states between different network devices and neighbor devices;

A processing module, configured to determine a primary path and a backup path of a first network device based on a plurality of link information, where the plurality of network devices includes the first network device, the primary path and the backup path are each configured to instruct the first network device to forward a path of data, the primary path includes a link between the first network device and a first neighbor device, and the backup path includes a link between the first network device and a second neighbor device;

And the sending module is used for sending the main path and the standby path to the first network equipment, wherein the standby path is used for being started when a link in the main path fails.

In one possible implementation, the receiving module is further configured to receive a first broadcast message from the first network device, where the first broadcast message includes first link information, and the first link information is used to indicate a link state between the first network device and a neighboring device, and link information between a child node device of the first network device and the neighboring device.

In one possible implementation, the receiving module is further configured 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 state between the first network device and the neighbor device.

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

or a sending module, configured to send a second unicast message, where the second unicast message includes a primary path and a backup path.

In one possible implementation, the sending module is further configured to send a routing broadcast message including a primary path and a backup path for each of the plurality of network devices.

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

A fifth aspect of the application provides a network device comprising a memory storing code and a processor configured to execute the code, the network device performing the method as in any one of the implementations of the first or second aspects when the code is executed.

A sixth aspect of the application provides a communication system comprising a network device as claimed in the third aspect and a network device as claimed in the fourth aspect.

A seventh aspect of the present application provides a computer readable storage medium having a computer program stored therein, which when run on a computer causes the computer to perform a method as in any one of the implementations of the first or second aspects.

An eighth aspect of the application provides a computer program product which, when run on a computer, causes the computer to perform a method as in any of the implementations of the first or second aspects.

A ninth aspect of the application provides a chip comprising one or more processors. Some or all of the processor is configured to read and execute a computer program stored in memory to perform a method according to any one of the implementations of the first or second aspects described above.

Optionally, the chip includes a memory, and the memory and the processor are connected to the memory through a circuit or a wire. Optionally, the chip further comprises a communication interface, and the processor is connected to the communication interface. The communication interface is used for receiving data and/or information to be processed, and the processor acquires the data and/or information from the communication interface, processes the data and/or information and outputs a processing result through the communication interface. The communication interface may be an input-output interface. The method provided by the application can be realized by one chip or a plurality of chips in a cooperative manner.

The technical effects of any one of the design manners of the second aspect to the ninth aspect may be referred to the technical effects of the different implementation manners of the first aspect, and are not described herein.

Drawings

Fig. 1 is a schematic structural diagram of a single-hop wireless network according to an embodiment of the present application;

Fig. 2 is a schematic structural diagram of a wireless mesh network according to an embodiment of the present application;

Fig. 3 is a schematic diagram of deployment of a wireless mesh network in a surface mine scenario provided by an embodiment of the present application;

fig. 4 is a schematic diagram of a wireless link of a wireless mesh network according to an embodiment of the present application;

Fig. 5 is a flow chart of a communication recovery method for link failure according to an embodiment of the present application;

fig. 6 is a schematic diagram of a tree topology constructed based on a wireless mesh network according to an embodiment of the present application;

fig. 7 is a schematic flow chart of link status reporting according to an embodiment of the present application;

fig. 8 is a schematic diagram of the format of a Beacon frame provided in the ieee802.11s standard;

Fig. 9 is a schematic diagram of a Neighbor Link Report element field format according to an embodiment of the present application;

fig. 10 is a schematic diagram of carrying link information through Neighbor Link Report element fields according to an embodiment of the present application;

Fig. 11 is a schematic diagram of another embodiment of carrying link information through Neighbor Link Report element fields;

fig. 12 is a schematic flow chart of a feedback link information through unicast message according to an embodiment of the present application;

fig. 13 is a schematic diagram of a primary path and a standby path of an equipment node according to an embodiment of the present application;

fig. 14 is a schematic diagram of a format of a path information field according to an embodiment of the present application;

Fig. 15 is a schematic flow chart of a method for a root node device to issue path information for a network device according to an embodiment of the present application;

Fig. 16 is a schematic flow chart of path information issuing according to an embodiment of the present application;

FIG. 17 is a schematic diagram of a standby path switching according to an embodiment of the present application;

FIG. 18 is a schematic flow chart of switching to a standby path according to an embodiment of the present application;

Fig. 19A is a schematic diagram of a node switching path in a wireless mesh network according to an embodiment of the present application, which is connected to another wireless mesh network;

Fig. 19B is a schematic diagram of a network management system monitoring a link state in a wireless mesh network according to an embodiment of the present application;

fig. 19C is a schematic diagram of implementing load sharing based on a link state in a wireless mesh network according to an embodiment of the present application;

Fig. 20 is a schematic structural diagram of a network device according to an embodiment of the present application;

fig. 21 is a schematic structural diagram of a network device according to an embodiment of the present application;

fig. 22 is a schematic structural diagram of a network device according to an embodiment of the present application;

fig. 23 is a schematic structural diagram of a computer readable storage medium according to an embodiment of the present application.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments.

The terms "first," "second," "third," "fourth" and the like in the description and in the claims and in the above drawings, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments described herein may be implemented in other sequences than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

WLAN technology based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard has been widely used in the enterprise, consumer, and carrier markets through which users can conveniently access the internet.

In mainstream WLANs, each client accesses the network via a wireless link with an AP to form a local Basic service set (Basic SERVICE SET, BSS). A user communicates with any terminal in the network, which must first access the AP, this network architecture is known as a single hop wireless network. To expand the wireless coverage area, it is often necessary to interconnect multiple APs using cables, switches, power supplies, etc., to form a larger-scale WLAN.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a single-hop wireless network according to an embodiment of the present application. As shown in fig. 1, stations (STAs) accessed to different APs need to forward through a wired network, where the STAs refer to terminal devices such as a smart phone, a notebook computer, a tablet computer, and the like. The STA accesses the external network, only one hop on the path is wireless connection, and the rest are wired connection.

In a single-hop wireless network, each AP needs to be connected with a wired network, a large amount of installation and deployment time is required when large-area wireless coverage is achieved, the cost is high, and once the AP is deployed, the position is difficult to move.

The wireless mesh network is a multi-hop wireless network, which is the biggest difference from a conventional single-hop wireless network in that a plurality of APs are connected using wireless connections instead of wired connections. The AP in the wireless mesh network not only provides a user access function, but also forwards data on a wireless link, so that the data is routed from one AP to another AP, and finally, the wireless mesh network is formed by accessing a wired network through a portal node.

Fig. 2 is a schematic structural diagram of a wireless mesh network according to an embodiment of the present application. As shown in fig. 2, APs can be divided into three roles, mesh Point (MP), mesh ingress node (Mesh Portal Point, MPP) and Mesh access Point (MESH ACCESS Point, MAP), according to functions in a wireless Mesh network.

The MP refers to a node that performs wireless communication using IEEE 802.11MAC and PHY protocols in the Mesh network and supports a Mesh function. MP supports functions such as automatic topology, automatic discovery of routes, forwarding of data packets, etc. In general, MP is also referred to as AP.

MAP refers to any MP that supports AP functionality and may provide access functionality for STAs. MAP can be considered as a special Mesh Point.

The MPP refers to a node that connects a wireless mesh network and other types of networks and communicates with other nodes inside the mesh network. The MPP has a Portal function, and through the MPP, nodes inside the wireless mesh network can communicate with an external network. MPP may also be considered a special MP.

The wireless mesh network removes wiring requirements among the APs, and installation selection is more flexible. In the wireless mesh network, if a new device is to be added, the device can be automatically configured by simply connecting a power supply, and an optimal multi-hop transmission path is determined. When an AP device is added or moved, the network can automatically discover topology changes and automatically adjust communication routes to obtain the most efficient transmission paths.

Compared with the traditional WLAN network, the wireless mesh network can remarkably reduce the deployment cost and provide greater convenience and expansibility. Therefore, the wireless mesh network is widely applied to the scenes of inconvenient wiring or high wiring cost such as large warehouses, ports and terminals, mine roadways, emergency communication and the like besides being applied to the common scenes of the traditional WLAN such as enterprise networks, office networks, campus networks and the like. At present, the standardization of the IEEE802.11s on the wireless mesh network is mainly in the aspects of wireless mesh network establishment, wireless mesh network security, mesh data message routing and the like, and the problem of connectivity of the wireless mesh network is solved.

However, with the wide application of the wireless mesh network, the inventor finds that there are some other problems with the wireless mesh network. For example, in some scenarios, the wireless channel between APs may change drastically, and even the position of the AP may move. Referring to fig. 3, fig. 3 is a schematic diagram of a wireless mesh network deployed in a surface mine scenario according to an embodiment of the present application. As shown in fig. 3, in the scenario of an open mine, the wireless links between APs may be obscured by the moving tall mine car, resulting in a dramatic drop in link quality, or even an unusable link. In addition, some APs are mounted on vehicles and as mining advances, the location may shift.

In general, the existing ieee802.11s standard mainly solves the problem of network connectivity under the condition that wireless connection is used between APs, and is not considered enough for the situation that the network topology needs to be dynamically adjusted, and does not pay attention to the situation that the wireless link between APs may change drastically in the use process, so that the situation that the wireless mesh network is easy to have large network delay, packet loss, and even service interruption in actual use, and the actual requirement of the service is difficult to be met.

In view of this, an embodiment of the present application provides a communication recovery method for link failure, where a network device in a wireless mesh network searches for a link state with a neighboring device, and reports the link state between the device and the neighboring device to a designated device in the wireless mesh network, so that the designated device can issue a main path and a standby path for each network device to instruct the network device to transmit data according to the link state between the network devices in the entire wireless mesh network. 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 pre-issued standby path 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 fails.

Fig. 4 is a schematic diagram of a wireless link of a wireless mesh network according to an embodiment of the present application. In the application scenario shown in fig. 4, a plurality of APs, AP1-AP9, are included. The AP1 is connected to an external network by a wire, and is an MPP. The AP5-AP9 is connected with a terminal device, and is the MAP described above, and is responsible for providing a wireless access function for the terminal device. AP2-AP4 provides a backhaul link from AP5-AP9 to the MPP, which is MP described above. That is, in the wireless mesh network, except for the AP1 as the MPP being connected to the external network through a wire, other APs are connected through wireless, and a function of forwarding data is provided for the terminal device through wireless links connected to each other. In fig. 4, the broken line between APs indicates that wireless signals can be transmitted and received between APs, and does not represent a data transmission path used between APs.

Specifically, the fast reroute process, i.e., the process of selecting a new link to restore network connectivity after a radio link failure, may include three phases, a link reselection trigger phase, a target link search phase, and a link reselection execution phase.

The link reselection triggering stage refers to making a switching decision at the most appropriate time to prevent excessive degradation of channel conditions, and the time consumption is related to a link monitoring policy.

The target link searching stage refers to acquiring a new target link by searching a wireless channel. This stage solves the problem of how to determine a new target node as soon as possible, which can provide connectivity to the wireless mesh network with a better link quality. Conventional devices typically require hundreds of milliseconds or even longer to complete the process.

The link reselection execution phase refers to the channel switch operation being performed by the radio interface, which may typically be done in a few milliseconds.

In the searching stage, the service data packet cannot be normally transmitted, and the time spent in the searching stage is too long, so that the service data packet is the most main cause of interruption. The core of the embodiments of the present application is therefore how to reduce, even eliminate, the delay introduced by the target link search process.

Since the target link search is a process of obtaining a new available link, the search phase may be cancelled if the new link information that the node needs to switch is known a priori, i.e. the node knows the information of the backup path when it detects a link failure. 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 directly performed to switch to the standby path, so that the node can recover from the link failure, thereby avoiding the occurrence of service interruption.

Therefore, the core of the embodiment is to solve the problem of how to efficiently maintain the standby path information for the node in real time, and after the link failure occurs, the node can accurately and quickly switch to the standby path. This involves the following four core steps.

And step 1, determining an initial network topology, namely configuring a designated node of the wireless mesh network as a master node, wherein if a designated mesh network entry node MPP is the master node, other nodes are slave nodes. And constructing tree-shaped or forest-shaped topology by taking the master node as a root node, and obtaining the path from each slave node to the master node. For example, in the following embodiments, the first network device is a slave node and the second network device is a master node.

And step 2, link state distributed monitoring and reporting, wherein each slave node keeps monitoring the link state of the neighbor node and reports the link quality to the father node layer by layer until the master node.

And step 3, the centralized generation and the issuing of the routing strategy, namely, the master node calculates a main path and a standby path from each node to the root node according to the neighbor node link information reported by each node and issues the main path and the standby path to each slave node.

And step 4, fast rerouting, namely each slave node keeps monitoring the link between the slave node and the father node, if the link is found out to be faulty, directly builds a link with the father node of the optimal standby path according to the standby path information stored locally, realizes fast rerouting, and informs the master node. The master node may regenerate and issue routing policies to adjust the routes taken by the failed nodes.

Referring to fig. 5, fig. 5 is a flow chart of a communication recovery method for link failure according to an embodiment of the present application. As shown in fig. 5, the method for recovering from link failure according to the embodiment of the present application includes the following steps 501 to 506.

In step 501, a first network device measures a link state between the first network device and a neighbor device.

In this embodiment, the first network device is any device other than the master node device in the wireless mesh network, for example, a physical device such as a router, a wireless switch, or a wireless transceiver. Specifically, the first network device may be a device in the wireless mesh network that provides a wireless access service for a terminal device of a user, or may be a device in the wireless mesh network that establishes wireless connection with other network devices to provide a data forwarding function. For example, the first network device may be any one AP of APs 2 to 9 in the wireless mesh network shown in fig. 4.

After the first network device is booted, the first network device may measure a link state between itself and surrounding neighbor devices. The number of the neighbor devices of the first network device is not limited in this embodiment. Specifically, the first network device may measure a link state with the neighbor device by searching surrounding neighbor devices first, and measuring a quality of a link between itself and the searched neighbor device. For example, the first network device may measure the strength of wireless signals transmitted by the neighbor device to determine the quality of the link between the first network device and the neighbor device. The first network device may obtain the quality of the link with the neighboring device by measuring a Signal-to-Noise Ratio (SNR) or a received Signal strength Indicator (RECEIVE SIGNAL STRENGTH Indicator, RSSI) of the wireless Signal, for example.

In general, a first network device can determine one or more neighbor devices located around the first network device by measuring link states between itself and the neighbor devices, and can obtain the quality of links between the first network device and each neighbor device.

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, and the first link information is used to indicate a link state between the first network device and a neighbor device.

After the link state between the first network device and the neighboring device is measured, the first network device may send the first link information to the second network device, so as to feedback the link state between the first network device and the neighboring device to the master node device in the wireless mesh network. The second network device is a designated device in the wireless mesh network, and is configured to receive link information reported by other network devices in the wireless mesh network, and further issue a corresponding main path and a corresponding standby path for each network device based on the obtained link information. Under the condition that the wireless mesh network completes the construction of the tree topology, the second network device is root node device in the tree topology, for example, the second network device is boundary device between the external network and the wireless mesh network and is responsible for providing the function of accessing the external network for the network device in the wireless mesh network. For example, the second network device is connected to an external network in a wired manner, and is connected to other network devices inside the wireless mesh network in a wireless manner.

As can be seen from fig. 4, each network device in the wireless mesh network is connected to other network devices, and only a part of the network devices (such as AP2-AP 4) are directly connected to the root node device, and the other network devices (such as AP5-AP 9) are connected to the root node device through their parent node devices. In fig. 4, the parent node device of the AP5-AP9 is directly connected to the root node device, that is, the wireless mesh network in fig. 4 may be actually divided into three layers, where the first layer is AP1 as the root node device, the second layer is AP2-AP4 having a link with the root node device, and the third layer is AP5-AP9 connected to the root node device through the parent node device. In practical applications, some of the parent node devices of the APs may also have parent node devices that are not directly connected to the root node device, so that the wireless mesh network actually has a structure with more than three layers.

Therefore, in the process that the first network device sends the first link information to the second network device, if a direct link exists between the first network device and the root node device, the first network device can directly send the first link information to the root node device without forwarding through other network devices, if no direct link exists between the first network device and the root node device, the first network device can send the first link information to the father node device of the first network device, the father node device of the first network device continues to send the first link information to the father node device of the upper layer, and so on, finally, the first link information is forwarded to the second network device.

In step 503, the root node device receives a plurality of link information, where the plurality of link information is from a plurality of network devices in the wireless mesh network, and the plurality of link information is used to indicate link states between different network devices and neighboring devices, respectively.

Since each network device except the root node device in the wireless mesh network performs a process of measuring a link state with the neighbor device and transmits link information indicating a link state between itself and the neighbor device to the root node device, the root node device can receive a plurality of link information. And the plurality of link information received by the root node device are from different network devices in the wireless mesh network, and each link information is used for indicating the link state between the network device and the neighbor device of the link information.

For example, taking the wireless mesh network shown in fig. 4 as an example, the AP1 as the root node device may receive 8 pieces of link information through the APs 2-AP4, and the 8 pieces of link information are respectively from the APs 2-AP9. And, the 8 link information are used to indicate the link states between itself and the neighbor devices measured by each of the APs 2-AP9, respectively.

The root node device determines a primary path and a backup path for the first network device based on the plurality of link information, step 504.

After the root node device obtains link information reported by different network devices in the wireless mesh network, the root node device can determine the link state between the network devices in the wireless mesh network based on the link information, so that a corresponding data transmission path is planned for any one network device in the wireless mesh network, and the data transmission path can be used for indicating the path of the network device for transmitting data to the root node device.

Taking a first network device in the wireless mesh network as an example, the root node device can determine a primary path and a backup path of the first network device based on a plurality of link information from a plurality of network devices. The primary path and the standby path are used for indicating a path of the first network device for forwarding data (i.e. a path of how the first network device sends the data to the root node device), the primary path comprises a link between the first network device and the first neighbor device, and the standby path comprises 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. That is, the primary 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, so as to ensure that the first network device can also send data to the root node device through the backup path when the link in the primary path fails.

The first link information sent by the first network device includes a link state between the first network device and the first neighbor device and a link state between the first network device and the second neighbor device. And, the link states of the first network device and the first neighbor device and the link states of the first network device and the second neighbor device both meet the requirement of data transmission, so the root node device determines that the main path comprises the link of the first network device and the first neighbor device, and the standby path comprises the link of the first network device and the second neighbor device.

In this embodiment, the root node device may determine a primary path and a backup path for a network device in the wireless mesh network by using a pre-configured path selection algorithm, and the path selection algorithm is not specifically limited in this embodiment. For example, the root node device comprehensively considers the link quality between the network devices and the load balancing condition of the links, distributes the main path and the standby path with higher link quality for each network device as much as possible, and can have balanced load between the main paths corresponding to different network devices.

It should be noted that, the root node device may issue a primary path and one or more backup paths to the first network device. That is, for any one network device, there is only one main path corresponding to the network device, and the standby path may have one or more standby paths.

In step 505, the root node device sends a primary path and a backup path to the first network device.

After determining the primary and backup paths of the first network device, the root node device may then send the primary and backup paths to the first network device. In the case of a link between the first network device and the root node device, the root node device may send the primary path and the backup path directly to the first network device. When the first network device and the root node device do not have a directly connected link, the root node device may send a primary path and a backup path to the first network device through other network devices between the first network device and the root node device.

Step 506, the first network device forwards the data through the backup path when the link in the primary path fails.

After the first network device receives the primary path and the backup path, the first network device may save the primary path and the backup path. And, during operation of the first network device, the first network device forwards data over the primary path. For example, when the first network device is connected to the terminal device, the first network device forwards data transmitted from the terminal device via the main path, and for example, when the first network device is not connected to the terminal device, the first network device receives data from the terminal device from other network devices and forwards the received data based on the main path.

In addition, when the first network device detects a link failure with the first neighbor device on the primary path, the first network device may query a pre-saved backup path and switch to the backup path to implement data forwarding. That is, when the link between the current network device and the neighbor device on the main path fails, the first network device quickly switches from the main path to the pre-stored standby path, so that the data acquired by the first network device can be forwarded through the standby path.

Optionally, after the link failure in the primary path, the first network device may send a route reset message to the second network device through the backup path, where the route reset message is used to indicate the link failure in the primary path. That is, the route reset message is equivalent to a message for notifying the second network device that a failure has occurred in the main path used on the first network device, the first network device having switched to the backup path. Therefore, the second network device can plan a new path for the first network device again, and then issue a more accurate new path for the first network device.

Specifically, after receiving the route reset message, the second network device determines a new main path and a new standby path for the first network device based on the route reset message, and sends the new main path and the new standby path to the first network device, so as to ensure that the first network device can realize the forwarding of data subsequently.

In addition, because the route reset message also indicates a failed link, when the second network device receives the data which is from the external network and is destined for the first network device, the second network device can forward the data to the first network device based on the newly-started path, thereby bypassing the failed link and ensuring that the first network device can successfully receive the data.

For ease of understanding, a detailed description will be given below of a specific procedure of exchanging link information and paths between a first network device and a root node device in a wireless mesh network.

First, a procedure of the first network device to interact link information with the root node device is described. The first network device and the root node device may interact link information in multiple manners.

In mode 1, a first network device transmits first link information to a root node device by transmitting a broadcast message.

The first network device transmits a first broadcast message, the first broadcast message including first link information. For example, the first broadcast message includes a Beacon (Beacon) frame, and the first link information is carried in an extension field or a Vendor Specific (Vendor Specific) field in the Beacon frame. In this way, in the case that 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, so as to implement that the first network device sends the first link information to the root node device. And under the condition that the root node is not the parent node equipment of the first network equipment, the parent node equipment of the first network equipment receives the first broadcast message sent by the first network equipment, and further forwards the first link information in the first broadcast message continuously. Similarly, each network device with the child node device forwards the link information in the broadcast message after receiving the broadcast message from the child node device, so as to ensure that the first link information sent by the first network device through the first broadcast message can be forwarded to the root node device.

Optionally, in the case that the first network device has a child node device, 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 then forwards the second link information to a second network device that is the root node device. In the scheme, under the condition that the father node equipment receives the link information broadcast by the child node equipment, the father node equipment forwards the link information for the child node equipment, so that the link information is reported step by step in the wireless mesh network, and the link information measured by all network equipment can be reported to the root node equipment.

For example, after receiving the second link information, the first network device transmits a second broadcast message to the second network device, the second broadcast message including 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 child node device through one broadcast message, so that the message overhead is reduced, and the transmission efficiency of the link information is improved.

Specifically, in the case where the wireless mesh network has completed topology construction, each network device in the wireless mesh network can store path information reaching the root node device, and parent node device information and all child node information of the present device in the network topology. In this way, each network device can complete transmitting link information to the root node device based on the stored path information and the parent node and child node device information.

For example, the tree topology of the wireless mesh network may be determined using an active tree construction mode (Proactive tree building mode) defined in the IEEE802.11 standard. In the wireless mesh network, a network device (that is, the MPP) connected to an external network through a wired manner is generally configured as a master node, and the remaining network devices are slave nodes. For example, in the above embodiment, the second network device is a master node, and the first network device is a slave node.

The master node will act as the root node of the tree, initiating the active tree construction process. The active tree construction process may use an active root announcement (Root Announcement, RANN) mechanism defined in IEEE802.11, where the master node announces itself as a root node of the tree to other nodes to construct a tree topology, thereby completing the construction of the network topology. After the construction of the tree topology is completed, on each slave node, the routing information to the root node and the parent node information of each node in the tree topology are stored. The master node stores the routing information of the whole tree topology. Fig. 6 is a schematic diagram of a tree topology constructed based on a wireless mesh network according to an embodiment of the present application. As shown in fig. 6, a tree topology may be constructed for the wireless mesh network shown in fig. 4. Wherein, AP1 is the master node, i.e. the root node in the tree topology. Moreover, AP1 is the parent node of AP2-AP4, AP2 is the parent nodes of AP5 and AP6, AP4 is the parent node of AP9, and AP3 is the parent nodes of AP7 and AP 8.

After the tree topology is established, each slave node in the wireless mesh network can measure the link state between the slave node and all the neighbor nodes, and the link state between the slave node and all the neighbor nodes is reported to the father node in a link information mode. After receiving the link information reported by the child node, the parent node attaches the link information of the parent node, and continuously reports the link information to the upper node (namely the parent node of the current parent node) until reporting to the root node.

Taking the tree topology established in fig. 6 as an example, the route from AP9 to root node AP1 is AP9→ap4→ap1. The flow of link measurement and reporting between the three nodes is shown in fig. 7, and fig. 7 is a schematic flow diagram of link status reporting in an embodiment of the present application. In fig. 7, the link state reporting includes the following procedure.

First, the AP9 and the AP4 as slave nodes measure link states between themselves and all neighbor devices in real time. That is, the AP9 may measure the link states between the AP9 and all neighbor devices and store the measured link state results, and the AP4 may also measure the link states between the AP4 and all neighbor devices and store the measured link state results.

Then, when the AP9 needs to report the link state to the root node (for example, the reporting period arrives, or the change value of the link quality between the AP9 and the neighbor device exceeds the preset threshold), the link state between the AP9 and all the neighbor devices is directly reported to the parent node (i.e., AP 4) on the route. Taking the wireless mesh network shown in fig. 4 as an example, the link state reported by the AP9 includes the state of the link between the AP9 and the AP4, and the state of the link between the AP9 and the AP 2. Wherein, AP9 reports the link status to parent node AP4, and may use broadcast messages.

And secondly, after receiving the link state reported by the AP9, the AP4 checks whether the link state from the child node is reported. After confirming that the link state reported by the AP9 is the link state reported by the child node thereof, storing the link state reported by the child node (i.e., the neighbor link measurement result reported by the child node), and generating a link state reporting message of the node in combination with the link state measured by the node, and further transmitting the link state reporting message to the parent node at the upper level. The link state report message sent by the AP4 to the parent node AP1 includes the link state reported by the child node AP9 of the AP4, and the link state measured by the node (such as the link state between the AP4 and the AP1, the link state between the AP4 and the AP2, the link state between the AP4 and the AP3, the link state between the AP4 and the AP6, and the link state between the AP4 and the AP 9).

In the process of reporting the link state by adopting the broadcast message, one implementation way is to reuse the existing Beacon mechanism and increase the measured link state with the neighbor device in the Beacon frame.

The Beacon frame is a broadcast frame periodically sent by an AP in the wireless mesh network, so that other nodes know the existence of the current AP and main information of the AP. According to the content defined by the IEEE802.11s standard, all nodes in the wireless mesh network need to periodically send Beacon frames, so that the characteristic of periodic broadcasting of Beacon frames can be adopted to realize the reporting of link states in the scheme.

For example, referring to fig. 8, fig. 8 is a schematic diagram of a Beacon frame format provided in the ieee802.11s standard. As shown in fig. 8, in the main Body (Frame Body) portion of the Beacon Frame, optional fields such as a Timestamp (Timestamp), a Beacon interval (Beacon interval), capability information (Capability Information), and a service set identifier (SERVICE SET IDENTIFIER, SSID) are in front, and optional fields such as a traffic indication map (Traffic indication map, TIM) field, a Country (county) field, a Power Constraint (Power Constraint) field, and a Vendor Specific (Vendor Specific) field are in back. The last optional field is a Vendor Specific field, which may have one or more fields, placed at the end of the Beacon frame.

When reporting link information using broadcast Beacon frames, a newly defined field for carrying link information, such as a neighbor link report element (Neighbor Link Report element) field, may be employed. That is, a new field (i.e., neighbor Link Report element field) is extended in the Beacon frame and link information is carried through the field.

Referring to fig. 9, fig. 9 is a schematic diagram illustrating a format of Neighbor Link Report element fields according to an embodiment of the present application. As shown in fig. 9, the Neighbor Link Report element field for carrying link information may include a device identifier, the number of neighbor devices, a neighbor device identifier, and a link quality metric value. The device identifier and the neighbor device identifier are used for uniquely identifying one network device in the wireless mesh network, and may specifically be represented by a media access Control Address (MEDIA ACCESS Control Address, MAC ADRESS). The link quality metric value is used to measure the quality of a wireless link between two network devices in the wireless mesh network, and may be specifically represented by LINK METRIC defined in a protocol. Specifically, the link quality metric value may be measured using an indicator such as RSSI or SNR. One or more Neighbor Link Report element fields may be included in a Beacon frame, each Neighbor Link Report element field corresponding to a link state reported by a network device.

In the example shown in fig. 7, when the AP9 reports information of two neighbor links (AP 9< - > AP4, AP9< - > AP 2) to the AP4, a Neighbor Link Report element field as shown in fig. 10 may be added to the Beacon frame sent by the AP 9. Fig. 10 is a schematic diagram of carrying link information through Neighbor Link Report element fields according to an embodiment of the present application. In fig. 10, the link information measured by the AP9 is carried by the AP9 in a Neighbor Link Report element field added in the broadcast message, which specifically includes the MAC address of the AP9, the number of neighbor devices measured by the AP9 is 2, the MAC address of the first neighbor device (AP 4), the quality metric value of the link between the AP9 and the AP4, the MAC address of the second neighbor device (AP 2), and the quality metric value of the link between the AP9 and the AP 2.

Further, when the AP4 reports its own neighbor link and its neighbor link of the child node AP9 to the AP1, the neighbor link reported by the AP9 (as shown in fig. 10) may be added in the transmitted Beacon frame, and then another Neighbor Link Report element field is adopted to attach 5 neighbor link information measured by the AP4 (AP 4< - > AP1, AP4< - > AP2, AP4< - > AP3, AP4< - > AP6, AP4< - > AP 9), as shown in fig. 11.

Considering that in the wireless mesh network, when network devices at both ends measure the quality of the same link, the measurement results are likely to be consistent. For example, in the example described above, 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, the AP4 serving as the parent node may omit LINK METRIC of the AP4< - > AP9 in its own neighbor link measurement result, i.e. only report the rest 4 neighbor link information, thereby saving message overhead.

Since the Beacon frame may further include one or more Vendor Specific fields, the link information measured by the network device may also be reported in the Vendor Specific field, that is, the link information is placed in an existing field of the Beacon frame for transmission. The advantage of carrying the link information in the original Vendor Specific field is that the inter-operation of different vendors is not affected, and errors caused when the third party Vendor equipment analyzes the Beacon frame when the link information is placed in other original fields are avoided.

Mode 2, the first network device sends the first link information to the root node device by sending a unicast message.

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

Specifically, if unicast messages are used for link state reporting, a new management frame may be defined to carry the link information. That is, the unicast message sent by the first network device includes an extended management frame, and the first link information may be carried in the extended management frame. In addition, in the case of reporting the link state by using a unicast message, a new field may be extended in an existing management frame of the IEEE802.11 standard. For example, in an existing mesh link metric Report (MESH LINK METRIC Report) frame, one or more newly defined fields carrying neighbor node link information, such as the Neighbor Link Report element field defined previously, are extended, and the link information is carried by the newly extended Neighbor Link Report element field and sent to the root node device.

Optionally, the process of reporting the link information by the network device through the unicast message may also be performed during the process of establishing the network topology, where the link information may be used as an input for establishing the network topology.

Specifically, in the IEEE802.11 standard, an active root node announcement RANN mechanism (Proactive RANN MECHANISM) is used to determine the routing of a root node to each node in a wireless mesh network. Proactive RANN MECHANISM mainly comprises the following processes:

The root node broadcasts a RANN message, and each node receiving the RANN needs to further transmit the RANN message so that the RANN message can be transmitted to all nodes in the wireless mesh network;

A node receiving the RANN message unicast transmits a Path Request (PREQ) frame to the root node;

The root node returns a unicast path reply (PATH REPLY, PREP) frame for each PREQ received.

In this embodiment, the node that receives the RANN may carry the link information measured by the node in PREQ and send the link information to the root node. Referring to fig. 12, fig. 12 is a schematic flow chart of a feedback link information through unicast messages according to an embodiment of the present application. As shown in fig. 12, in the PREP frame sent by the AP4 and the AP9, a Neighbor Link Report element field is added, and the format of the Neighbor Link Report element field may be defined in the previous embodiment. Wherein Neighbor Link Report element field in the PREP frame sent by AP4 carries the link states of AP4 and all neighbor devices, neighbor Link Report element field in the PREP frame sent by AP9 carries the link states of AP9 and all neighbor devices. Thus, after the master node receives PREP of all the slave nodes, the link state between each node and the neighbor node in the whole wireless mesh network can be known.

In general, the link state reporting is performed by using broadcast messages, which is suitable for the slave node to periodically report the neighbor link state, and the link state reporting is performed by using unicast messages, which is suitable for the slave node to report the neighbor link state after the event triggering. The combination of the two different reporting modes enables the master node to master the link quality of each node in the whole network in real time.

After the network device in the wireless mesh network reports the link state between itself and the neighbor device to the root node device, the root node device can obtain the state of each link in the whole wireless mesh network. In this way, the root node device can select a main path and a standby path for each network device in the wireless mesh network according to a preset routing method.

Referring to fig. 13, fig. 13 is a schematic diagram of a primary path and a backup path of an equipment node according to an embodiment of the present application. As shown in fig. 13, the AP1 as the root node device can obtain a quality metric value for 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. The main path and the standby path planned by the AP1 for the AP9 are shown in table 1 below.

TABLE 1

As shown in Table 1, the main path planned by AP1 for AP9 is AP1-AP4-AP9, the quality metric value of the path is 0.6, and the standby path planned by AP1 for AP9 is AP1-AP2-AP9, the quality metric value of the path is 0.8.

The backup path planned by the root node device for the network device in the wireless mesh network may be determined according to an actual link condition, for example, one or more backup paths are planned for one network device, which is not limited in this implementation.

When the root node device issues the primary path and the backup path for the network device, a newly defined field may be used in the issued message to carry the primary path and the backup path, for example, a newly defined path information field (Route Information element) may be used to carry the path information. Specifically, each path may be carried using a path information field. The Route Information element field will indicate information of all network devices through which the path passes.

Referring to fig. 14, fig. 14 is a schematic diagram illustrating a format of a field of path information according to an embodiment of the present application. As shown in fig. 14, in Route Information element field, a quality Metric value (Metric) of the path, the hop count, and an identification of each network device traversed may be included. Wherein the quality metric value of the path may be used to identify the priority of the present route, the identification of the network device may use the MAC address of the network device.

One or more Route Information element fields as shown in fig. 14 may be included in a management frame sent by the root node device to a network device in the wireless mesh network, where each Route Information element field represents a path (such as the primary path or the backup path described above) allocated by the root node device to the network device.

In addition, when the root node device issues the main path and the standby path for the network device, the root node device may use a broadcast message or a unicast message to implement the path issue.

When the root node device adopts a unicast message to issue a path, the root node device may carry a main path and a standby path planned for a specific network device in the unicast message issued to the network device.

Fig. 15 is a schematic flow chart of a root node device sending path information for a network device according to an embodiment of the present application. As shown in fig. 15, the AP1 as the root node device may carry the primary path and the standby path between the AP1 and the AP4 in the path response frame sent to the AP4, and the AP1 as the root node device may carry the primary path and the standby path between the AP1 and the AP9 in the path response frame sent to the AP9, so as to implement the issuing of the primary path and the standby path in the construction process of the network topology.

When the root node device adopts the broadcast message to issue the path, the root node device can carry the main path and the standby path corresponding to all the slave node devices in the wireless mesh network in the broadcast message. And then, the network equipment receiving the broadcast message determines a main path and a standby path of the equipment based on the broadcast message and continuously forwards the broadcast message, so that the child node equipment of the current network equipment can also receive the broadcast message, and finally, the broadcast message issued by the root node equipment can be diffused in the whole wireless mesh network.

Optionally, after the network device in the wireless mesh network receives the broadcast message, the path related to the device in the broadcast message may be removed, so that only the path related to the child node device is broadcasted and issued. For example, in the broadcasting of the path, the first network device may receive a third broadcast message including the primary path and the backup path of the first network device and the primary path and the backup path of the child node device of the first network device. Based on the third broadcast message, the first network device may generate a fourth broadcast message including the primary path and the backup path of the child node device of the first network device. In this way, the child node device of the first network device can acquire the main path and the standby path of the device after receiving the fourth broadcast message.

Referring to fig. 16, fig. 16 is a schematic flow chart of path information issuing according to an embodiment of the present application. As shown in fig. 16, after determining the primary paths and the backup paths of all the slave node APs, the AP1 as the root node device may broadcast the path information on the air interface, that is, send a broadcast message carrying the primary paths and the backup paths corresponding to all the slave node APs.

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 parent nodes. If the received broadcast message is from its parent node, the primary and backup paths of the node are saved based on the broadcast message. In addition, if the node also has a lower node (i.e. other nodes below the current node in the tree topology), the main paths and the standby paths corresponding to all the lower nodes are extracted from the broadcast message, a new broadcast message is generated, and the new broadcast message carries the main paths and the standby paths corresponding to all the lower nodes.

For example, after receiving the broadcast message sent by the AP1, the AP2 extracts the main path and the standby path corresponding to the AP6 from the received broadcast message because the AP2 has the subordinate node AP6, and generates a new broadcast message carrying the main path and the standby path corresponding to the AP6, so as to continue sending the new broadcast message. Similarly, after receiving the broadcast message sent by the AP1, the AP4 extracts the main path and the standby path corresponding to the AP9 from the received broadcast message because the AP4 has the subordinate node AP9, and generates a new broadcast message carrying the main path and the standby path corresponding to the AP9, so as to continue sending the new broadcast message.

The broadcast message carrying the primary path and the standby path of the slave node sent on the air interface can use the existing Beacon mechanism, for example, one or more Route Information element are carried in the Beacon frame to represent the path information, and can also use the broadcast frame similar to the gate announcement (Gate Announcement) frame to carry out the path information issuing.

In general, in the wireless mesh network, the root node device can select an appropriate main path and backup path for each network device based on link information of the entire wireless mesh network, and issue to each network device. In the process of path issuing, the path issuing is carried out in the form of broadcast messages, which is suitable for the root node equipment to periodically refresh the main path and the standby path of the network equipment, and the path issuing is carried out in the form of unicast messages, which is suitable for the event triggering to refresh the path information for the specific network equipment. Through the combination of the two path issuing modes, the network equipment in the wireless mesh network can always acquire a main path and a standby path between the network equipment and the root node equipment in real time.

After the root node device performs the issuing of the path information, each network device in the wireless mesh network can acquire a main path and a standby path of the device. During normal operation, the network device employs the primary path to transmit data. And, the network device continuously monitors the link between the device and the parent node device. When a link between the network device and the parent node device fails, for example, the signal strength or quality of the link between the network device and the parent node device is lower than a certain threshold value, or the network device does not receive information (such as a Beacon frame or other heartbeat information) periodically sent by the parent node device, the network device triggers a standby path enabling mechanism, that is, enables the standby path to replace the main path for data transmission.

Referring to fig. 17, fig. 17 is a schematic diagram illustrating a standby path switching according to an embodiment of the application. As shown in FIG. 17, in the wireless mesh network, the main path of AP9 is AP9< - > AP4< - > AP1, and the standby path is AP9< - > AP2< - > AP1. When the AP9 detects that the link between the node and the father node AP4 fails, the standby path is started according to the standby path stored locally and is connected to the new father node AP2, so that the AP9 can realize data forwarding through the AP2, and interruption of data transmission service is avoided.

Referring to fig. 18, fig. 18 is a schematic flow chart of switching to a standby path according to an embodiment of the application. As shown in fig. 18, the process of switching paths from the node AP9 includes the following steps.

First, the link state between the AP9 and the parent node AP4 is always monitored from the node AP 9. After discovering a link failure between AP9 and AP4, AP9 triggers a reroute escape mechanism. Specifically, the slave node AP9 inquires the backup path stored in the slave node, and decides to switch to the backup path.

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

Next, the slave node AP9 reports the route reset message to the master node AP 1. The route reset message may reuse existing Path Error (PERR) messages. Optionally, in the case that the AP9 is issued multiple backup paths, the AP9 may further add a path information element (Route Information element) field in the route reset message to identify which backup path is initiated from the node AP 9.

Optionally, after receiving the route reset message of the AP9, the master node AP1 calculates a new path after removing the link of the AP4< - > AP9, and issues the new path to each affected node. Wherein the new path may be a path including a new primary path and a backup path. The specific process of the master node AP1 issuing the new path is as described in the previous embodiment, and will not be described herein.

Table 2 below may be referred to, where table 2 is used to indicate the change of address attached when sending packets in the new and old data channels before and after the AP9 enables the standby path.

	Address 1	Address 2	Address 3	Address 4
					Before enabling the alternate path	MAC_AP4	MAC_AP9	MAC_STA2	MAC_STA1
After the standby path is started	MAC_AP2	MAC_AP9	MAC_STA2	MAC_STA1

Table 2 corresponds to the wireless mesh network shown in fig. 17, and the node STA1 under the AP9 transmits a packet to the node STA2 under the AP 8. The packet sent by the AP9 should include 4 addresses before and after enabling the standby path, and the meanings of the 4 addresses are respectively:

Address 1 is the address of the receiver of the link of the present hop, namely the address of the father node of the AP 9. Before the standby path is enabled, address 1 is the MAC address of AP4, and after the standby path is enabled, address 1 is changed to the MAC address of AP 2.

Address 2. The address of the sender of the link of the present hop, i.e. the address of the AP9 itself.

Address 3: the receiver address of the original data, i.e., the address of STA 2.

Address 4 is the sender address of the original data, i.e., the address of STA 1.

That is, after the standby path is started, the AP9 modifies the address 1 in the data packet sent by the air interface from the MAC address of the AP4 to the MAC address of the AP2, so that a data channel to the new parent node AP2 can be established, and path escape is completed.

Optionally, when reporting the path reset information to the master node, the slave node may report the neighbor link information, for example, the Neighbor Link Report element field is carried in the PERR, so that the master node can better determine the new path.

In general, after the slave node triggers the link reselection, the traditional link searching process is omitted, and the standby link is directly started to be connected to a new parent node, so that the time delay caused by the link searching is avoided, the error node is also avoided from being selected by the slave node, and the problem that the service is interrupted due to the fact that the connectivity with the original wireless mesh network is not recovered is avoided.

The above embodiments are presented with the network device in the wireless mesh network enabling the backup path to reconnect to the root node device in the wireless mesh network through the new link after the network device finds the link failure. However, in some embodiments, root node devices in different wireless mesh networks connected through the distributed system DS (Distributed System) may exchange network topology information and link information in the wireless mesh network, so that when the network device in a certain wireless mesh network is connected to the root node device, the network device can access to another wireless mesh network, so as to connect to the root node device in another wireless mesh network, and avoid interruption of data service responsible for the network device.

For example, referring to fig. 19A, fig. 19A is a schematic diagram of a node switching path in a wireless mesh network connected to another wireless mesh network according to an embodiment of the present application. As shown in fig. 19A, the APs 1-6 belong to the same wireless mesh network (i.e., WMN1 in fig. 19A), and the APs 7-11 belong to another wireless mesh network (i.e., WMN2 in fig. 19A). Moreover, the AP1 and the AP11 are root nodes in the wireless mesh network, and the AP1 and the AP11 are connected in a wired manner. During normal operation of the two wireless mesh networks, the AP1 and the AP11 as root nodes may exchange network topology information and link information between nodes in the wireless mesh networks with each other. In this way, the AP1 and the AP11 can actually know the link information between the nodes in the two wireless mesh networks clearly. Then, if AP7 has only a link to AP11 in WMN2, in the path issuing stage, AP11 may issue a backup path for AP7 with a parent node being AP6, so that AP7 can access the wireless mesh network where AP1 is located based on the backup path.

In the case of the failure of the AP11, the AP7 detects that the link between the AP7 and the AP11 fails, so that the AP7 may enable the parent node to be a standby path of the AP6, thereby connecting to the AP6, and finally connecting to the root node AP1 in another wireless mesh network through the AP6 and the AP4, so as to maintain the connectivity of the network to the maximum extent.

In other embodiments, in the case that the plurality of network devices in the wireless mesh network report the link information to the designated device, the link information reported by the plurality of network devices may have other purposes besides the primary path and the backup path for generating each network device.

Fig. 19B is a schematic diagram of a network management system for monitoring a link state in a wireless mesh network according to an embodiment of the present application. As shown in fig. 19B, 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 is a slave node. During operation of the wireless mesh network, all APs in the wireless mesh network measure link states between themselves and neighboring nodes, and all slave nodes report the measured link states (i.e., link states between the slave node and the neighboring nodes) to AP 1. Then, the AP1 transmits the measured link states of all APs (including itself) in the entire wireless mesh network to the network management system, either actively or in response to a request of the network management system.

In this way, the network management system can acquire the link states between the APs in the whole wireless mesh network, thereby realizing the monitoring of the link states of the APs. For example, the network management system can also display the acquired link states between APs to the user, so that the user can monitor the links between APs according to actual needs.

Fig. 19C is a schematic diagram illustrating load sharing based on a link state in a wireless mesh network according to an embodiment of the present application. As shown in fig. 19C, the wireless mesh network includes AP1-AP9, where AP1 is a master node connected to an external network through a wired network, and AP2-AP9 is a slave node. STA1 is connected to the AP1, STA4 is connected to the AP4, and STA9 is connected to the AP 9. During operation of the wireless mesh network, all APs in the wireless mesh network measure link states between themselves and neighboring nodes, and all slave nodes report the measured link states to AP 1.

After the AP1 acquires the link state between the APs in the wireless mesh network, the AP1 selects a main path (AP 1< - > AP4< - > AP 9) and a standby path (AP 1< - > AP2< - > AP 9) for the slave node AP9, wherein the link quality of the main path is slightly better than that of the standby path.

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 of AP1 to AP9 includes the link between AP1 and AP4, and the link is also required to transmit data sent by STA1 to STA 4. Thus, to avoid congestion of the link between AP1 and AP4, AP1 may employ the following data transmission policy:

1, forwarding all data sent by the STA1 to the STA4 through a link between the AP1 and the AP 4;

2, transmitting the data sent by the STA1 to the STA9, wherein one part of the data is transmitted through a main path of the AP9, namely, is transmitted through a link between the AP1 and the AP4, and the other part of the data is transmitted through a standby path of the AP9, namely, is transmitted through a link between the AP1 and the AP 2;

in this way, by using the main path and the standby path to forward data at the same time, link congestion can be avoided, and communication rate can be improved.

The above embodiments describe a communication recovery method for link failure provided by the embodiments of the present application, and an apparatus for performing the communication recovery method for link failure described above will be described below.

Referring to fig. 20, fig. 20 is a schematic structural diagram of a network device according to an embodiment of the present application. As shown in fig. 20, a network device provided by an embodiment of the present application is a slave node device in a wireless mesh network, where the network device includes:

a measurement module 2001 for measuring a link state between the first network device and the neighbor device;

A sending module 2002, configured 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 neighbor device;

a receiving module 2003, configured to receive a main path and a standby path from a second network device, where the main path and the standby path are both used to instruct a first network device to forward a path of data, the main path includes a link between the first network device and a first neighboring device, and the standby path includes a link between the first network device and the second neighboring device;

The sending module 2002 is further configured to forward data through the backup path when a link in the primary path fails.

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

In one possible implementation manner, the second network device is a root node device in a tree topology constructed based on the wireless mesh network, and in the case that the first network device has a child node device, the receiving module 2003 is further configured to receive 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, and the sending module 2002 is further configured to forward the second link information to the second network device.

In one 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.

In one possible implementation manner, the second network device is a root node device in a tree topology constructed based on the wireless mesh network, the receiving module 2003 is further configured to receive 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, and the sending module 2002 is further configured to forward the second link information to the second network device.

In one 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.

In a possible implementation, the receiving module 2003 is further configured to receive a third broadcast message, where the third broadcast message includes a primary path and a standby path of the first network device and a primary path and a standby path of a child node device of the first network device, and the sending module 2002 is further configured to send a fourth broadcast message, where the fourth broadcast message includes a primary path and a standby path of the child node device of the first network device.

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

or the second unicast message includes a path reply frame in which the primary path and the backup path of the first network device are carried.

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

Referring to fig. 21, fig. 21 is a schematic structural diagram of a network device according to an embodiment of the present application. As shown in fig. 21, the network device provided by the embodiment of the present application is a master node device in a wireless mesh network, where the network device includes:

a receiving module 2101, configured to receive a plurality of link information, where the plurality of link information is from a plurality of network devices in the wireless mesh network, and the plurality of link information is respectively used to indicate link states between different network devices and neighboring devices;

A processing module 2102 configured to determine a primary path and a backup path of the first network device based on the plurality of link information, where the plurality of network devices includes the first network device, the primary path and the backup path each being configured to instruct the first network device to forward a path of data, the primary path including a link between the first network device and a first neighbor device, the backup path including a link between the first network device and a second neighbor device;

a transmitting module 2103 for transmitting a primary path and a backup path to the first network device, the backup path being for enabling upon a link failure in the primary path.

In one possible implementation, the receiving module 2101 is further configured to receive a first broadcast message from a first network device, where the first broadcast message includes first link information, and the first link information is used to indicate a link state between the first network device and a neighboring device, and link information between a child node device of the first network device and the neighboring device.

In one possible implementation, the receiving module 2101 is further configured 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 state between the first network device and the neighboring device.

In one 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;

or the sending module 2103 is further configured to send a second unicast message, the second unicast message comprising a primary path and a backup path.

In one possible implementation, the sending module 2103 is further configured to send a routing broadcast message including a primary path and a backup path for each of the plurality of network devices.

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

Next, referring to fig. 22, fig. 22 is a schematic structural diagram of a network device according to an embodiment of the present application, where the network device 2200 may be embodied as a cat or a router, which is not limited herein. Specifically, the network device 2200 includes a receiver 2201, a transmitter 2202, a processor 2203, and a memory 2204 (where the number of processors 2203 in the network device 2200 may be one or more, and one processor is illustrated in fig. 22), where the processor 2203 may include an application processor 22031 and a communication processor 22032. In some embodiments of the application, the receiver 2201, transmitter 2202, processor 2203, and memory 2204 may be connected by a bus or other means.

Memory 2204 may include read only memory and random access memory and provides instructions and data to processor 2203. A portion of memory 2204 may also include non-volatile random access memory (NVRAM). The memory 2204 stores a processor and operating instructions, executable modules or data structures, or a subset thereof, or an extended set thereof, wherein the operating instructions may include various operating instructions for performing various operations.

The processor 2203 controls the operation of the network device. In a specific application, the various components of the network device are coupled together by a bus system, which may include a power bus, a control bus, a status signal bus, and the like, in addition to a data bus. For clarity of illustration, however, the various buses are referred to in the figures as bus systems.

The method disclosed in the above embodiment of the present application may be applied to the processor 2203 or implemented by the processor 2203. The processor 2203 may be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the methods described above may be performed by integrated logic circuitry in hardware or instructions in software in the processor 2203. The processor 2203 may be a general purpose processor, a Digital Signal Processor (DSP), a microprocessor, or a microcontroller, and may further include an Application Specific Integrated Circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, or discrete hardware components. The processor 2203 may implement or perform the methods, steps, and logic blocks disclosed in embodiments of the application. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be embodied directly in the execution of a hardware decoding processor, or in the execution of a combination of hardware and software modules in a decoding processor. The software modules may be located in a random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in the memory 2204, and the processor 2203 reads the information in the memory 2204, and in combination with the hardware, performs the steps of the method.

The receiver 2201 may be used to receive input numeric or character information and to generate signal inputs related to the relevant settings and function control of the network device. The transmitter 2202 may be configured to output numeric or character information via a first interface, the transmitter 2202 may also be configured to send instructions to the disk pack via the first interface to modify data in the disk pack, and the transmitter 2202 may also include a display device such as a display screen.

In one embodiment of the present application, the processor 2203 is configured to perform the method of the corresponding embodiment of fig. 5.

The network device provided by the embodiment of the application can be a chip, wherein the chip comprises a processing unit and a communication unit, the processing unit can be a processor, and the communication unit can be an input/output interface, a pin or a circuit, and the like. The processing unit may execute the computer-executable instructions stored in the storage unit to cause a chip within the network device to perform 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, or the like, and the storage unit may also be a storage unit in the wireless access device side located outside the chip, such as a read-only memory (ROM) or other type of static storage device that may store static information and instructions, a random access memory (random access memory, RAM), or the like.

Referring to fig. 23, fig. 23 is a schematic structural diagram of a computer readable storage medium according to an embodiment of the present application. The present application also provides a computer readable storage medium, in some embodiments, the method disclosed in FIG. 5 above may be embodied as computer program instructions encoded on a computer readable storage medium in a machine readable format or on other non-transitory media or articles of manufacture.

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

In one embodiment, computer-readable storage medium 2300 is provided using signal-bearing medium 2301. The signal bearing medium 2301 may include one or more program instructions 2302 that, when executed by one or more processors, may provide the functions or portions of the functions described above with respect to fig. 5. Further, program instructions 2302 in fig. 23 also describe example instructions.

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

In some implementations, the signal bearing medium 2301 may contain a computer recordable medium 2304 such as, but not limited to, memory, read/write (R/W) CD, R/W DVD, and the like. In some implementations, 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., fiber optic cable, waveguide, wired communications link, wireless communications link, etc.). Thus, for example, the signal bearing medium 2301 may be conveyed by a communication medium 2305 in wireless form (e.g., a wireless communication medium that complies with the IEEE 802 standard or other transmission protocol).

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

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

The computer program product includes one or more computer instructions. When loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present invention, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. 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 one website, computer, server, or data center to another website, computer, server, or data center by a wired (e.g., coaxial cable, fiber optic, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be stored by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk Solid STATE DISK (SSD)), etc.

It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, which are not repeated herein.

In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of 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.

In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in part or all of the technical solution or in part in the form of a software product stored in a storage medium, including instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. The storage medium includes a U disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a magnetic disk, an optical disk, or other various media capable of storing program codes.

While the application has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that the foregoing embodiments may be modified or equivalents may be substituted for some of the features thereof, and that the modifications or substitutions do not depart from the spirit and scope of the embodiments of the 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, wherein the first network device sends the first link information to the second network device, comprising:

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, and when the first network device has a child node device, the method further comprises:

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 is 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 VendorSpecific field in the first Beacon frame.

5. The method according to claim 2, wherein the first unicast message comprises 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 1-5 is characterized in that the first link information includes the identification of the first network device, the number of neighbor devices of the first network device, the identification of the neighbor device, and the link quality measurement value between the first network device and the neighbor device.

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, wherein the first network device receives the primary path and the backup path from the second network device, comprising:

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 also 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 extended 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 1-11, 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, wherein the second network device receives a plurality of link information, comprising:

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 , wherein the first broadcast message comprises 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, wherein the second network device receives a plurality of link information, comprising:

The second network device receives a first unicast message sent by a sub-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 15-18, characterized in that the primary path and the backup path include at least one of the following contents: 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, wherein the second network device sends the primary path and the backup path to the first network device, comprising:

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 is characterized in that 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 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 15-22, 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 comprises:

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 device comprises:

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, comprising 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 by comprising the network device according to claim 25 and the network device according to claim 26.

29. A computer storage medium, characterized in that the computer storage medium stores instructions, and when the instructions are executed by a computer, the computer implements the method according to 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, enable the computer to implement the method according to any one of claims 1 to 24.