CN109995541B

CN109995541B - Multicast data sending method and node equipment

Info

Publication number: CN109995541B
Application number: CN201711486779.2A
Authority: CN
Inventors: 赵金
Original assignee: Beijing Huawei Digital Technologies Co Ltd
Current assignee: Beijing Huawei Digital Technologies Co Ltd
Priority date: 2017-12-29
Filing date: 2017-12-29
Publication date: 2021-08-31
Anticipated expiration: 2037-12-29
Also published as: CN109995541A

Abstract

A multicast data sending method and node equipment are provided, the method comprises: a first node device sends first multicast data sent by a multicast source to a client through a main link, wherein the main link is a link configured between the first node device and a second node device in advance, the first node device is connected with the multicast source, and the second node device is connected with the client; the first node device to the second node device are further configured with a standby link, and at least one third node device on the standby link and the first node device can send multicast data by using a broadcast mode; a first node device receives a Signal Failure (SF) message, wherein the SF message is used for indicating that the main link fails and triggering the first node device and the at least one third node device to start the broadcast mode; and the first node equipment broadcasts the second multicast data received after the SF message is received.

Description

Multicast data sending method and node equipment

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a multicast data transmission method and a node device.

Background

In order to perform link backup and improve network reliability in an ethernet switching network, a redundant link is usually used, and the redundant link generates a loop on the switching network, which causes fault phenomena such as a broadcast storm and unstable Media Access Control (MAC) address table, thereby causing poor communication quality of a user, and even communication interruption.

In order to solve the loop problem caused by using the redundant link, a two-layer loop-breaking protocol may be deployed on the devices forming the Ring network, for example, an Ethernet Ring Protection Switching (ERPS) protocol, where the two-layer loop-breaking protocol sets a blocking point in the Ring network, and the blocking point may block all messages from passing through, thereby blocking the redundant link of the loop and preventing broadcast storm.

Referring to fig. 1, a two-layer fragmentation protocol is taken as an example of an ERPS protocol to describe the operation of the two-layer fragmentation protocol in the prior art:

the node device A, the node device B, the node device C and the node device D form a ring network, the node device A is connected with the client, and the node device D is connected with the routing device. Two paths exist between the node device D and the node device A, one path is a path D-C-A, and the other path is a path D-B-A. Assume that a congestion point is set between node device a and node device B. When the loop is in a normal working state, one multicast table entry is prestored in the node device D and the node device C and is a path D-C-A, after the node device D receives multicast data sent by the routing device, the multicast data is sent to the node device C according to the prestored multicast table entry, then the node device C sends the multicast data to the node device A, and finally the node device A sends the multicast data to a client. Because a blocking point is arranged between the node device A and the node device B, the node device on the link where the path D-B-A is positioned has no multicast table item due to the non-protocol message delivery, when the path D-C-A has a fault, the node equipment on the path D-B-A firstly releases the blocking point according to the received Signal Fail (SF) message sent by the node equipment on the path D-C-A, then waits for the router to resend an Internet Group Management Protocol (IGMP) query command (query), then after receiving the query command, sending feedback information corresponding to the command to the node device D, thereby establishing a multicast table item corresponding to the path D-B-A, and finally sending multicast data according to the established new multicast table item.

Because the period for the routing device to send the query command is long, usually 60s or 125s, and the node device usually needs about 10s to respond to the query command, if a link failure occurs during multicast data transmission, the time required for temporarily creating a new multicast entry is long, which may cause multicast service interruption or great delay in multicast data transmission, and affect the performance of the multicast service.

Disclosure of Invention

The embodiment of the application provides a multicast data sending method and node equipment, which are used for solving the technical problems that in the prior art, if a link failure occurs in the process of transmitting multicast data, due to the fact that the time required for temporarily creating a multicast table entry is long, the multicast service is interrupted or the multicast data transmission is delayed greatly, and the performance of the multicast service is affected.

In a first aspect, a method for transmitting multicast data is provided, the method including: after receiving first multicast data sent by a multicast source connected with the first node device, the first node device sends the first multicast data to a second node device connected with a client through a main link configured between the first node device and the second node device in advance, so that the first multicast data is sent to the client through the second node device; a standby link is configured between the first node device and the second node device, the main link and the standby link form a loop, at least one third node device on the standby link and the first node device can send multicast data in a broadcast mode, and the broadcast mode of the at least one third node device and the first node device is in a closed state in the process that the first node device sends the first multicast data to the client through the main link; then, in the process that the first node device sends multicast data through the main link, a signal failure SF message is received, where the SF message is used to indicate that the main link is failed, and the SF message is used to trigger the first node device and the at least one third node device to start the broadcast mode, so that the first node device broadcasts, to the second node device through the standby link, second multicast data received after receiving the SF message, and the second node device sends the second multicast data to the client.

In the technical scheme, broadcast capabilities are configured for the first node device and at least one third node device on the standby link, and when a main link which is transmitting multicast data fails, the broadcast capabilities of the first node device and the node devices on the standby link are started; then, the first node device broadcasts the multicast data received after determining that the main link fails on the standby link, and further broadcasts the multicast data to the second node device, and finally the second node device sends the multicast data to the client.

In a possible implementation manner, the first node device establishes a multicast entry corresponding to the main link in advance, and after receiving the first multicast data, the first node device sends the first multicast data to the client through the main link based on the pre-stored multicast entry.

In the above technical solution, when the main link on the loop has no fault, the node device may forward the multicast data according to the pre-stored multicast table entry.

In a possible implementation manner, the first node device broadcasts the second multicast data after determining that the received second multicast data satisfies a condition, where a starting character string of a destination MAC address of the second multicast data is a preset character string.

In the above technical solution, since there are multiple types of data transmitted on the loop, for example, multicast data may be transmitted, and unicast data may also be transmitted, after receiving data transmitted by a multicast source, the first node device may first determine whether the data is multicast data according to a start character string of a destination MAC address of the data, and if the data is multicast data, the first node device may transmit the data in a broadcast manner.

In a possible implementation manner, during the period when the first node device broadcasts the received second multicast data, since the routing device connected to the multicast source periodically sends an IGMP query packet, when the time when the routing device sends the IGMP query packet arrives, the first node device receives the IGMP query packet, and then forwards the IGMP query packet to at least one third node device in the standby link except the first node device and the second node device to forward the IGMP query packet to the client, when the client sends a response message corresponding to the IGMP query packet to the second node device, the second node device feeds back the response message to the first node device through the at least one third node device, and after receiving the response message, the first node device establishes a new multicast table entry corresponding to the standby link according to the response message, and after the broadcast mode is closed, the third multicast data sent by the multicast source is sent to the client through the standby link based on the new multicast table item.

In the above technical solution, during the period when the first node device broadcasts the second multicast data, the first node device may establish the multicast table entry of the standby link according to the IGMP query packet sent by the routing device and the response message of the client to the IGMP query packet, so that the sending of the multicast data and the establishment of the multicast table entry may be performed synchronously, thereby reducing the delay in the transmission of the multicast data.

In a possible implementation manner, after determining that the duration of broadcasting the second multicast data is equal to a preset duration, the first node device closes its broadcast mode, where the first node device is connected to the multicast source through a routing device, the preset duration is a sum of an interval duration of sending an internet group management protocol, IGMP, query packet to the first node device by the routing device and a duration of forwarding a response message corresponding to the IGMP query packet by a node device in the standby link, and the response message is generated for the client.

In the above technical solution, since the duration of the broadcast multicast data is the sum of the interval duration of the internet group management protocol IGMP query packet sent by the router to the first node device and the duration of the response message corresponding to the IGMP query packet forwarded by the node device in the standby link, it can be ensured that a new multicast table entry can be established during the broadcast period after the first node device and the at least one third node device finish broadcasting.

In a possible implementation manner, during a period when the first node device broadcasts the received second multicast data, if a failure on the main link is recovered, the first node device receives a recovery NR packet for indicating the failure recovery in the main link, and then, after the node device on the standby link blocks the blocked interface again, the first node device receives a ring network protection switching recovery NRRB packet for indicating that the blocked port on the standby link is in a blocked state, and restarts a pre-stored multicast entry, and when receiving fourth multicast data sent by the multicast source, sends the fourth multicast data to the client through the main link based on the pre-stored multicast entry.

In the above technical solution, since the communication quality, occupied bandwidth, and the like of the standby link are generally not good as those of the main link, in order to ensure effective utilization of resources, after the first node device receives the NR packet during the broadcast period, the first node device may be switched to the main link again to transmit the multicast data.

In a possible implementation manner, when the first node device determines that the recovered NR packet sent by the node device in the main link is received during the process of broadcasting the second multicast data, the broadcast mode of the first node device is turned off.

When the first node device receives the NR packet during the broadcast, the broadcast mode may be turned off, which may save broadcast resources.

In a second aspect, a method for transmitting multicast data is provided, the method including: a first node device connected with a multicast source sends first multicast data sent by the multicast source to a client through a main link, the main link is a link through which the first node device and a second node device are communicating, the second node device is a node device connected with the client, wherein the first node device to the second node device comprise the main link and a standby link, the main link and the standby link form a loop, a third node device is located on the standby link, and the third node device and the first node device can send multicast data by using a broadcast mode, during the process that the first node device sends the first multicast data to the client through the main link, the broadcast mode of the third node device and the first node device are in a closed state, during the communication process, when the third node device receives a failure signal failure message for indicating that the main link has a failure SF, the broadcast mode is started, so that when the third node device receives the second multicast data after receiving the SF message, the second multicast data is broadcasted until the second multicast data is broadcasted to the second node device, and the second node device sends the second multicast data to the client.

In the above technical solution, a broadcast capability is first configured for at least one third node device, and when a main link that is transmitting multicast data fails, the broadcast capability of the third node device is enabled, so that second multicast data transmitted by a first node device is broadcast on a standby link, and finally the second node device transmits the second multicast data to a client.

In a possible implementation manner, during the broadcasting of the second multicast data by the third node device, the third node device receives an IGMP query packet forwarded by the first node device, where the IGMP query packet is sent by a routing device connected to the first node device, then the third node device sends the IGMP query packet to a fourth node device or the second node device connected to the third node device until the IGMP query packet is sent to the client, and forwards a response message of the client to the IGMP query packet to the third node device by the second node device or the fourth node device, after receiving the IGMP query packet, the third node device sends the response message to the first node device, so that the first node device establishes a new multicast table entry corresponding to the backup link according to the response message, and when the first node device sends the third multicast data, and transmitting the third multicast data to the client based on the new multicast table entry.

In the above technical solution, during the period when the first node device broadcasts the second multicast data, a multicast entry with the standby link may be established according to the IGMP query packet sent by the routing device and the response message of the client to the IGMP query packet, so that the sending of the multicast data and the establishment of the multicast entry may be performed synchronously, thereby reducing the delay in the transmission of the multicast data.

In a possible implementation manner, after determining that the duration of broadcasting the second multicast data is equal to a preset duration, the third node device closes its broadcast mode, where the preset duration is a sum of an interval duration of sending an internet group management protocol, IGMP, query packet to the first node device by the routing device and a duration of forwarding a response message corresponding to the IGMP query packet by the node device in the standby link, and the response message is generated by the client.

In a possible implementation manner, when the third node device determines to receive the NR recovery packet sent by the node device in the main link during the process of broadcasting the second multicast data, the broadcast mode of the third node device is turned off.

When the third node device receives the NR packet during the broadcast, the broadcast mode may be turned off, which may save broadcast resources.

In a third aspect, a first node device is provided, where the first node device has a function of implementing the behavior of the first node device in the method of the first aspect. The functions can be realized by hardware, and the functions can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In one possible design, the first node device has a structure including a processor configured to support the apparatus to perform corresponding functions of the method of the first aspect, and a memory for coupling with the processor, which stores necessary program instructions and data.

In a fourth aspect, a third node device is provided, which has a function of implementing the behavior of the third node device in the method of the second aspect. The functions can be realized by hardware, and the functions can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In one possible design, the third node device has a structure including a processor configured to support the apparatus to perform the corresponding functions of the method of the second aspect, and a memory for coupling with the processor, which stores necessary program instructions and data.

In a fifth aspect, a computer storage medium is provided, which is used to store computer software instructions for executing the first aspect, the second aspect, any design of the first aspect, any design of the second aspect, the functions of the first aspect, and the functions of the second aspect, and which contains a program designed to execute the first aspect, the second aspect, any design of the first aspect, any design of the second aspect, the method of the first aspect, and the method of the second aspect.

In a sixth aspect, this application provides a computer program product including instructions that, when executed on a computer, cause the computer to perform any one of the designs of the first aspect, the second aspect, the first aspect, and the second aspect.

In a seventh aspect, an embodiment of the present application further provides a chip system, where the chip system includes a processor, configured to support a first node device to implement the method according to the first aspect and support a third node device to implement the method according to the second aspect, for example, to generate or process data and/or information involved in the method. In one possible design, the system-on-chip further includes a memory for storing program instructions and data necessary for the web page layout apparatus. The chip system may be formed by a chip, or may include a chip and other discrete devices.

Drawings

Fig. 1 is a schematic diagram of a first networking mode of a two-layer ring network;

fig. 2 is a schematic diagram of a second networking mode of a two-layer ring network;

fig. 3 is a flowchart of a method for sending multicast data according to an embodiment of the present application;

fig. 4 is a flowchart of the steps executed after step 307 in the multicast data sending method provided in the embodiment of the present application;

fig. 5 is a flowchart of another execution step after step 307 of the multicast data transmission method provided in the embodiment of the present application;

fig. 6 is a schematic structural diagram of a first node device provided in an embodiment of the present application;

fig. 7 is a schematic structural diagram of a third node device provided in an embodiment of the present application;

fig. 8 is another schematic structural diagram of a node device according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship, unless otherwise specified.

The embodiment of the application provides a multicast data sending method and node equipment, and the method can be applied to an Ethernet switching network with a two-layer ring network protection Protocol, wherein the two-layer ring network protection Protocol can be an ERPS Protocol, a Spanning Tree Protocol (STP), a Multiple Spanning Tree Protocol (MSTP) or the like. For example, as shown in fig. 1, a single-ring networking structure formed by a node device a, a node device B, a node device C, and a node device D may be a cross-ring networking structure as shown in fig. 2, the node device a, the node device B, the node device C, the node device D, and the node device E form a ring network, and the node device a, the node device B, the node device C, the node device D, and the node device F form another ring network, which are crossed, although other networking manners may also be used, which are not listed herein. The ethernet switching network with the two-layer ring network protection protocol deployed will be described below by taking an example in which the two-layer ring network protection protocol is an ERPS protocol and the networking mode is the single-ring networking structure shown in fig. 1.

The node device a, the node device B, the node device C, and the node device D in the switching network form an ERPS ring, and the node device a-node device D may be a device in charge of functions such as data processing and data forwarding, such as a switch, a router, or a hub. Node device a configures three ports, which are port 1, port 2 and port 3, node device B configures port 4 and port 5, node device C configures port 6 and port 7, and node device D configures port 8, port 9 and port 10. The node device a is connected to the client through the port 1, connected to the node device C through the port 2 and the port 6, and connected to the node device B through the port 3 and the port 4, the node device B is connected to the node device D through the port 5 and the port 9, the node device C is connected to the node device D through the port 7 and the port 8, the node device D communicates with the multicast source through the port 10, at least one router may be provided between the multicast source and the node device D, as shown in fig. 1, the port 10 is connected to the router. The port 4 is an Owner (Owner) port of a Ring Protection Link (RPL), the port 3 connected to the port 4 is a neighbor (neighbor) port of the RPL, and a Link between the port 3 and the port 4 is the RPL, and when the RPL Owner port is blocked, the port can block all messages. Under the condition that the ERPS ring network normally operates, the RPL owner port and the RPL neighbor port are blocked to prevent the generation of the ring.

The ERPS ring network forwards the multicast data through the multicast list item. When the ERPS ring network is initially established, a router connected with the node device D sends an Internet Group Management Protocol (IGMP) query command (query) to the node device of the ERPS ring network, after receiving the query message, the node device on the ERPS ring network forwards the query message to the client, and after responding to the query message, the client generates an IGMP report, and then the IGMP report is fed back to the node device sending the query message, i.e., the router, so that through an interaction process of the query message, the node device D and the node device C obtain and store a multicast entry, i.e., a path D-C-a. Since the port 4 is an RPLOwner port and is in a blocked state, the path D-B-a including the port 4 cannot interact according to the query message, and thus a multicast table entry with the path D-B-a is not formed. Therefore, when the multicast source sends the multicast data, the ERPS ring network sends the multicast data to the client through the path D-C-A corresponding to the multicast list item.

It can be seen that, in the prior art, the multicast data is sent according to the stored multicast table entry, and when a link corresponding to the stored multicast table entry fails, the ERPS ring network needs to reestablish a new multicast table entry. The establishment of the multicast table entry is realized by adopting an interaction mode between a query message at a router side and a report protection message at a client side, and the router can only periodically send the query message, so that if a link failure occurs in the process of transmitting multicast data, the time required for temporarily establishing the multicast table entry is longer, which may cause multicast service interruption or great time delay of multicast data transmission, and influence the performance of the multicast service.

In view of this, an embodiment of the present application provides a method for sending multicast data, where the method includes: after receiving first multicast data sent by a multicast source connected with the first node device, the first node device sends the first multicast data to a second node device connected with a client through a main link configured between the first node device and the second node device in advance, so that the first multicast data is sent to the client through the second node device; a standby link is configured between the first node device and the second node device, the main link and the standby link form a loop, at least one third node device on the standby link and the first node device can send multicast data in a broadcast mode, and the broadcast mode of the at least one third node device and the first node device is in a closed state in the process that the first node device sends the first multicast data to the client through the main link; then, in the process that the first node device sends multicast data through the main link, a signal failure SF message is received, where the SF message is used to indicate that the main link is failed, and the SF message is used to trigger the first node device and the at least one third node device to start the broadcast mode, so that the first node device broadcasts, to the second node device through the standby link, second multicast data received after receiving the SF message, and the second node device sends the second multicast data to the client.

In the following description, the technical solution provided by the embodiment of the present application is applied to the ERPS ring network shown in fig. 1, and a first node device is taken as a node device D in fig. 1, a second node device is taken as a node device a in fig. 1, and a third node device is taken as a node device B in the following description.

Please refer to fig. 3, which is a flowchart of a multicast data sending method according to an embodiment of the present application, where the flowchart is described as follows:

step 301: the node device D sends the first multicast data sent by the multicast source to the client through the main link.

In the ERPS ring network shown in fig. 1, two links, namely a link corresponding to the path D-C-a and a link corresponding to the path D-B-a, are included between the node device D and the node device a. Since the port 4 of the node device D is set as the RPL Owner port, the link corresponding to the path D-C-a is referred to as a primary link, and the link corresponding to the path D-B-a is referred to as a backup link.

When there is no fault in the ERPS ring network, the node device D sends the first multicast data to the client through the link corresponding to the pre-stored multicast entry when receiving the first multicast data sent by the multicast source. The multicast table entry can be established through a query message sent by a router when the ERPS ring network is initially established, and then is stored in the node device D and the node device C, so that when the node device D receives first multicast data forwarded by the router, the node device D determines that the pre-stored multicast table entry is routing information of a main link, and then sends the first multicast data to the node device C, and then the node device C determines to send the first multicast data to the node device A according to the multicast table entry stored by the node device C, and then the node device A sends the first multicast data to a client, so that the transmission of the first multicast data is realized.

Step 302: and the node equipment A and the node equipment C send signal failure SF messages, wherein the SF messages are used for indicating that the main link fails.

In the process of using the primary link to send the first multicast data, if the primary link fails, for example, a link between the node device C and the node device a fails, or a port of the node device C and a port of the node device a fails, for example, a port 6 fails, etc., the node device a and the node device C notify the change of the ring states of other node devices in the ERPS ring network, that is, the node device a sends a Signal Failure (SF) message to the node device B, and the node device C sends the SF message to the node device D to notify the node device D and the node device B that the primary link fails.

Step 303: and the node equipment D receives the signal failure SF message.

And when the node device D receives the SF message sent by the node device C, determining that the main link fails.

Because the ERPS ring network sends multicast data according to the stored multicast table entry in a non-failure state, the node device D can process the stored multicast table entry after receiving the SF message. For example, the multicast table entry may be deleted, or the multicast table entry may be set to a disabled state, so that when the node device D determines that the main link fails, the multicast data is not forwarded according to the multicast table entry any more. It should be noted that the process of processing the multicast entry is an optional step, i.e., it is not necessary to perform it.

Step 304: and the node equipment B receives the signal failure SF message and releases the RPL Owner port.

After the node device a and the node device C send SF messages to other node devices in the ERPS ring network, the node device B receives the SF message sent by the node device a, thereby determining that a failure occurs in the primary link.

When the node device B determines that the main link fails, the main link cannot send multicast data, at this time, the node device B releases the blocking state of the RPL Owner port, that is, opens the port 4, and at this time, the standby link D-B-a is in a conducting state.

It should be noted that, in the embodiment of the present application, the execution sequence of step 303 and step 304 is not limited, that is, step 303 may be executed simultaneously with step 304, or step 304 may be executed after step 303 is executed, or step 303 may be executed after step 304 is executed, and a specific execution sequence is determined according to the networking structure and the link state of the ERPS ring network.

Step 305: and the node device D starts a broadcast mode and broadcasts the second multicast data received after receiving the SF message.

When the node device D receives the second multicast data after receiving the SF packet, the node device D broadcasts the second multicast data at the port 8 and the port 9, and the main link corresponding to the port 8 fails, so that the second multicast data is blocked on the main link. And the backup link corresponding to the port 9 has no fault and the port 4 is unblocked, so that the second multicast data can be broadcasted on the backup link. Of course, since the main link fails, after receiving the second multicast data, the node device D may only broadcast the second multicast data on the port 9, which may reduce the waste of broadcast resources.

In this embodiment, in order to enable the node device on the ERPS ring network to implement the broadcast function, the node device on the ERPS ring network may be configured with the broadcast function in advance. For example, a broadcast function may be configured for the node device D of the ERPS ring network and the node device B on the standby link, and of course, all the node devices on the ERPS ring network may also be configured with a broadcast function. Further, in order to ensure the normal working state of the ERPS ring network, an ERPS switch may be configured for the broadcast function, and when the ERPS switch is in an on state, the node device having the broadcast function starts the broadcast function, and at this time, the node device having the broadcast function may send the multicast data in a broadcast manner as long as it receives the multicast data. When the ERPS switch is in a closed state, the node equipment with the broadcasting function closes the broadcasting function, and at the moment, the node equipment sends the multicast data according to the multicast list item.

It should be noted that, when the ERPS ring network is in a failure-free state, the ERPS switch is in a closed state, and when the ERPS ring network has a failure, for example, the node device a and the node device C send SF messages to the node device B and the node device D, the SF messages may also be used to enable the ERPS switches of the node device D and the node device B, so as to start the broadcast mode of the node device D and the node device B.

In this embodiment of the present application, before the node device D broadcasts the second multicast data, the following process may be further performed:

step 306, the node device D judges that the received second multicast data meets the condition; wherein the condition is that a starting character string of a destination Media Access Control (MAC) layer address of the second multicast data is a preset character string.

Since there may be multiple types of data sent simultaneously in the ERPS ring network, for example, unicast data and multicast data may be sent simultaneously, and of course, other types of data may also be sent, the method in the embodiment of the application is only suitable for the process of sending the multicast data, therefore, the node device D needs to determine the data received after receiving the SF message, determine whether the data is multicast data, for example, it is possible to determine whether the destination MAC of the received data is a predetermined character string corresponding to the multicast data, for example, the predetermined character string is 01005E, if the condition is satisfied, the node device D determines that the currently received data is the second multicast data, and broadcasting the second multicast data, otherwise, sending the second multicast data according to the sending mode of the data of the corresponding data type.

It should be noted that step 306 may be an optional step, i.e. it is not necessary to perform it. For example, it is preset that only multicast data is transmitted on the ERPS ring network, and the data received by the node device D is necessarily multicast data, in this case, the step 306 does not need to be executed, and the present invention is not limited thereto.

Step 307: node device B initiates the broadcast mode and will broadcast upon receiving the second multicast data.

After receiving the SF message sent by the node device a, the node device B starts a broadcast mode. After receiving the second multicast data broadcast by the node device D through the port 9, the second multicast data is broadcast to the node device a through the port 4, so that the node device a sends the second multicast data to the client.

Therefore, after the main link fails, the multicast data can be sent to the client quickly without waiting for newly establishing a multicast table item, so that the time delay of multicast data transmission can be reduced, and the performance of the multicast service is improved.

In this embodiment of the application, after step 307, the data sending method provided in this embodiment of the application may further include the following steps, please refer to fig. 4, which is a flowchart of the steps executed after step 307 by the method in this embodiment of the application, and the flow is described as follows:

step 401: the node device D receives the IGMP query message.

In the specific implementation process, the IGMP query message is a query message, and the query message is sent by a router connected to a multicast source. The router sends the query message periodically, for example, the period may be 60 s.

And the node device D waits for the router to send the query message in the process of broadcasting the second multicast data. For example, if the node device receives the SF message 10s after the router last sends the query message, the node device D receives the query message sent by the router again 50s after receiving the SF message.

Step 402: and the node device D forwards the IGMP query message to the node device B.

And after receiving the query message, the node device D sends the query message to the node device B.

Step 403: after receiving the IGMP query packet forwarded by the node device D, the node device B forwards the IGMP query packet to the node device a.

Of course, if another node device, for example, a fourth node device, is further disposed between the node device B and the node device a, the node device B sends the query packet to the fourth node device, and then the fourth node device forwards the query packet to the node device a. In the embodiment of the present application, the node apparatus B and the node apparatus a are directly connected to each other as an example.

Step 404: after receiving the IGMP message, the node device a sends the IGMP message to the client, and feeds back a response message IGMP report of the client to the IGMP message to the node device B.

Step 405: after receiving the response message, the node device B feeds back the response message to the node device D.

After receiving the intermediate response message of the node device a, the node device B establishes a multicast table entry, i.e., a path B-a, with the node device a, generates a new response message, and sends the new response message to the node device D.

Step 406: and the node device D receives the response message sent by the node device B and establishes a new multicast table item corresponding to the standby link.

After receiving the response message sent by the node device B, the node device D establishes a new multicast entry, i.e., a path D-B-a, according to the response message.

Step 407: node device D and node device B determine to turn off the broadcast mode.

In the embodiment of the present application, node device D and node device B determine whether to turn off the broadcast mode according to the broadcast duration. And after determining that the time length for broadcasting the second multicast data is equal to a preset time length, the node device D and the node device B close the broadcast mode of the node device B, wherein the preset time length is the sum of the interval time length for sending an Internet Group Management Protocol (IGMP) query message to the node device D by the router and the time length for forwarding a response message corresponding to the IGMP query message by the node device in the standby link, and the response message is generated by the client. For example, the period of sending the query message by the router is 60s, the total time length for forwarding the response message corresponding to the query message by the node device D, the node device B, and the node device a is 20s, and the preset time length is 60+ 20-80 s.

Because the preset time length is the sum of the interval time length of the internet group management protocol IGMP query message sent by the router to the node device D and the time length of the response message corresponding to the IGMP query message forwarded by the node device in the standby link, it can be ensured that a new multicast table entry can be established in the broadcasting period after the node device D and the node device B finish broadcasting.

Specifically, a timer may be provided in each of the node device D and the node device B, and the two timers may be synchronized in time. After the node device D and the node device B start the broadcast function, the timers in the respective devices may be started at the same time, so as to time the broadcast time. And when the timer is overtime, the broadcasting function is closed. Of course, it is also possible to set a timer only in the node device D, and the node device D controls the broadcast function of the node device B to be turned off, when the timer in the node device D times out, the node device D sends control information to the node device B, and the node device B turns off the broadcast function after receiving the control information.

Step 408: after the node device D and the node device B close the broadcast mode, the third multicast data sent by the multicast source is sent to the client through the new multicast entry.

And after the node device D and the node device B close the broadcast mode, sending third multicast data received after the broadcast mode is closed according to a new multicast table item established in the broadcast period. Specifically, when the node device D receives the third multicast data after the broadcast mode is turned off, the third multicast data is sent to the node device B according to the new multicast entry, and then the node device B sends the third multicast data to the node device a, and finally the node device a sends the third multicast data to the client. Thereby switching the transmission link of the multicast data from the main link to the standby link.

In practical applications, the channel quality of the main link is usually better than that of the standby link or the bandwidth of the main link is larger than that of the standby link, so that the link for transmitting the multicast data can be switched to the main link again after the failure of the main link is recovered. Specifically, after the failure between the node apparatus a and the node apparatus C is recovered, the node apparatus a and the node apparatus C transmit the recovery message (No Request, NR) to the node apparatus B and the node apparatus D, and the node apparatus B re-blocks the RPL Owner port after receiving the NR message, and sends No Request RPL Blocked, NRRB message to other node devices on the ERPS ring network to inform the blocking point that it has been Blocked again, at this time, the node device D broadcasts the multicast data received after receiving the NRRB message again, that is, the multicast data is broadcast from the port 8 by the node D, and then after the node C receives the multicast data from the port 7, the multicast data is broadcasted to the node device a from the port 6, and finally the node device a sends the multicast data to the client. During the broadcast, the node device a, the node device C, and the node device D have already reestablished the multicast entry corresponding to the main link, and after the broadcast is finished, the node device a, the node device C, and the node device D are switched to the main link again to send multicast data. The process of switching from the standby link to the main link is similar to the process of switching from the main link to the standby link, and please refer to the descriptions in fig. 3 to fig. 4, which is not described herein again.

In the method described in fig. 4, the time required for recovering the failure between the node apparatus a and the node apparatus C is longer, and the failure is recovered after the broadcast mode is turned off, and in practical applications, the time required for recovering the failure between the node apparatus a and the node apparatus C may also be shorter, for example, the failure is recovered during the broadcast, in this case, the method in the embodiment of the present application may further include the following step after step 307, please refer to fig. 5, which is a flowchart of the execution steps after step 307 of the method in the embodiment of the present application, and the flowchart describes the following step:

step 501: node device A and node device C send NR messages to node device B and node device D; wherein the NR packet is used to indicate failure recovery in the main link.

When the fault between the node device a and the node device C is recovered when the broadcast time length does not reach the preset time length, the node device a sends an NR packet to the node device B, and the node device C sends an NR packet to the node device D.

Step 502: and after receiving the NR message, the node device D closes the broadcast mode thereof.

Step 503: after receiving the NR packet, the node device B also closes its own broadcast mode, and blocks the RPL Owner port again.

Step 504: and the node device B sends a ring network protection switching recovery NRRB message to the node device D, wherein the NRRB message is used for indicating that a blocking interface in the standby link is in a blocking state.

Step 505: and after receiving the NRRB message, the node device D restarts the main link to send the fourth multicast data sent by the multicast source.

In a possible implementation manner, the node device D may control a use state of a pre-stored multicast entry, and when the node device D receives an SF message, the use state of the pre-stored multicast entry is set to a disabled state, in which case, the node device D cannot use the multicast entry; after receiving the NRRB message, the node device sets the use state of the pre-stored multicast entry to the enabled state, and at this time, the node device D may send multicast data according to the pre-stored multicast entry again. Thus, after the node device D receives the NRRB message, the multicast table entry, i.e., the path D-C-a, pre-stored in the node device D may be adjusted from the disabled state to the enabled state. Then, the node device D sends the fourth multicast data received after receiving the NRRB packet to the node device C, then the node device C sends the fourth multicast data to the node device a, and finally the node device a sends the fourth multicast data to the client, so that the complexity of switching links when the ERPS ring network fails can be reduced.

In the above technical solution, by configuring the broadcast capability for the node devices on the ring network, when the ring network fails and needs to be switched back after failure recovery, the multicast data received by the node devices on the ring network is broadcast for a certain time on other node devices of the ring network, so that the delay of sending the multicast data during switching of the ring network state can be reduced, fast switching is realized, the packet loss time can be reduced, and the performance of the multicast service can be improved.

In the embodiments provided in the foregoing application, the multicast data sending method provided in the embodiments of the present application is introduced from the perspective of each node device on the ring network. It is understood that each node device in the ring network includes a hardware structure and/or a software module for performing each function in order to implement the above functions. Those of skill in the art would readily appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

Fig. 6 shows a schematic diagram of a possible structure of a first node device 600. The first node apparatus 600 may implement the functionality of the first node apparatus referred to above. The first node apparatus 600 may include a receiving module 601 and a transmitting module 602. Wherein receiving module 601 may be configured to perform step 303 in the embodiment shown in fig. 3 or step 401 in the embodiment shown in fig. 4, and/or other processes for supporting the techniques described herein. The sending module 602 is configured to perform step 301, step 305 in the embodiment described in fig. 3, or step 402 and step 405 in the embodiment shown in fig. 4, and/or other processes for supporting the techniques described herein. All relevant contents of each step related to the above method embodiment may be referred to the functional description of the corresponding functional module, and are not described herein again.

Fig. 7 shows a possible structural diagram of the third node device 700. The third node device 700 may implement the functionality of the third node device that is referred to above as a re-referred to. The third node device 700 may comprise a receiving module 701, a processing module 702 and a sending module 703. Receiving module 701 may be used, among other things, to perform step 304 in the embodiment shown in fig. 3, and/or other processes for supporting the techniques described herein. Processing module 702 may be used to perform step 307 in the embodiment shown in fig. 3 or step 407 in the embodiment shown in fig. 4 or step 503 in the embodiment shown in fig. 5, and/or other processes for supporting the techniques described herein. The sending module 703 may be used to perform step 307 in the embodiment shown in fig. 3 or step 405 in the embodiment shown in fig. 4 or step 504 in the embodiment shown in fig. 5, and/or other processes for supporting the techniques described herein. All relevant contents of each step related to the above method embodiment may be referred to the functional description of the corresponding functional module, and are not described herein again.

In the embodiment of the present application, the first node device 600 and the third node device 700 may be presented in the form of dividing each function module corresponding to each function, or may be presented in the form of dividing each function module in an integrated manner. A "module" herein may refer to an application-specific integrated circuit (ASIC), a processor and memory that execute one or more software or firmware programs, an integrated logic circuit, and/or other devices that may provide the described functionality.

In a simple embodiment, it will be appreciated by those skilled in the art that any one of the first node device 600 and the third node device 700 may also be implemented by the structure shown in fig. 8.

As shown in fig. 8, the node apparatus 800 may include: a memory 801, a processor 802, a system bus 803, and a communication interface 804. The processor 802, the memory 801, and the communication interface 804 are connected by a system bus 803, the memory 801 may be provided in the processor 802, and the memory 801 and the processor 802 may be implemented by chips. The memory 801 is used for storing computer executable instructions, and when the node device 800 operates, the processor 802 executes the computer executable instructions stored by the memory 801 to cause the node device 800 to execute the embodiment shown in fig. 3, the embodiment shown in fig. 4 and the embodiment shown in fig. 5. For a specific implementation method, reference may be made to the above description and the related description in the drawings, which are not repeated herein. The communication interface 804 may be a transceiver, or a separate receiver and transmitter, among other things. Alternatively, the system bus 803 may be replaced by a star-configured or other configuration of connection devices, which is not limited herein.

In one example, the receiving module 601 and the sending module 602 may correspond to the communication interface 804 in fig. 8.

In one example, the receiving module 701 and the sending module 703 may correspond to the communication interface 804 in fig. 8, and the processing module 702 may correspond to the processor 802 in fig. 8. The processing module 702 may be embedded in hardware/software or may be separate from the memory 801 of the node apparatus 800.

Alternatively, the node device 800 may be a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a system on chip (SoC), a Central Processing Unit (CPU), a Network Processor (NP), a digital signal processing circuit (DSP), a Micro Controller Unit (MCU), or a Programmable Logic Device (PLD) or other integrated chips. Alternatively, the communication apparatus 900 may also be a separate network element, for example, a network device or a terminal device.

The node device provided by the present application may be a chip system, and the chip system may include at least one chip, and may also include other discrete devices. The chip system can be placed in a node device, and supports the node device to complete the multicast data transmission method provided in the embodiment of the present application.

An embodiment of the present application provides a computer storage medium, where instructions are stored in the computer storage medium, and when the instructions are run on a computer, the instructions cause the computer to execute the foregoing multicast data sending method.

An embodiment of the present application provides a computer program product, where the computer program product includes instructions, and when the instructions are run on a computer, the instructions cause the computer to execute the foregoing multicast data sending method.

In the above embodiments, the implementation may be wholly or partially realized 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, cause the processes or functions described in accordance with the embodiments of the application to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for transmitting multicast data, comprising:

the first node equipment sends first multicast data sent by a multicast source to a client through a main link; the main link is a link configured between the first node device and a second node device in advance, the first node device is connected with the multicast source, and the second node device is connected with a client;

a standby link of the main link is further configured between the first node device and the second node device, the main link and the standby link form a loop, at least one third node device on the standby link and the first node device can send multicast data in a broadcast mode, and in a process that the first node device sends the first multicast data to the client through the main link, the broadcast mode of the at least one third node device and the first node device is in a closed state;

a first node device receives a Signal Failure (SF) message, wherein the SF message is used for indicating that the main link fails, and the SF message is used for triggering the first node device and the at least one third node device to start the broadcast mode;

the first node device broadcasts second multicast data received after receiving the SF message, so that at least one third node device on the standby link continues broadcasting after receiving the second multicast data broadcast by the first node device until the second multicast data is broadcasted to the second node device, and the second node device sends the second multicast data to the client;

the first node equipment receives an IGMP query message, wherein the first node equipment is connected with the multicast source through routing equipment, and the IGMP query message is sent by the routing equipment;

the first node device forwards the IGMP query message to at least one third node device except the first node device and the second node device in the standby link;

the first node device receives a response message which is sent by the at least one third node device and corresponds to the IGMP query message;

and the first node equipment establishes a new multicast table item corresponding to the standby link according to the response message, and sends third multicast data sent by the multicast source to the client through the standby link based on the new multicast table item.

2. The method of claim 1, wherein the first node device sends the first multicast data sent by the multicast source to the client via the main link, and wherein the method comprises:

the first node equipment determines a multicast table item prestored by the first node equipment as the routing information associated with the main link;

and after receiving the first multicast data, the first node equipment sends the first multicast data to the client through the main chain based on the multicast table item.

3. The method of claim 1, wherein prior to the first node device broadcasting the second multicast data, the method further comprises:

the first node equipment judges that the received second multicast data meets the condition; wherein the condition is that an initial character string of a destination Media Access Control (MAC) layer address of the second multicast data is a preset character string.

4. The method according to any of claims 1-3, wherein after the first node device broadcasts the second multicast data received after receiving the SF packet, the method further comprises:

the first node equipment receives a recovered NR message; the NR packet is used to indicate failure recovery in the main link;

the first node equipment receives a looped network protection switching recovery NRRB message; the NRRB message is used for indicating a blocking interface in the standby link to be in a blocking state;

the first node equipment restarts a prestored multicast table item, and when receiving fourth multicast data sent by the multicast source, the first node equipment sends the fourth multicast data to the client through the main link based on the prestored multicast table item; and the pre-stored multicast list item is the routing information associated with the main link.

5. The method of claim 1, further comprising:

and after the first node equipment determines that the time length for broadcasting the second multicast data is equal to a preset time length, closing a broadcasting mode of the first node equipment, wherein the first node equipment is connected with the multicast source through a routing equipment, the preset time length is the sum of the interval time length for the routing equipment to send an Internet Group Management Protocol (IGMP) query message to the first node equipment and the time length for the node equipment in the standby link to forward a response message corresponding to the IGMP query message, and the response message is generated by the client.

6. The method of claim 4, wherein after the first node device broadcasts the second multicast data, the method further comprises:

the first node equipment closes the broadcast mode of the first node equipment when determining that the NR recovery message sent by the node equipment in the main link is received in the process of broadcasting the second multicast data; wherein the NR packet is used to indicate failure recovery of the main link.

7. A method for transmitting multicast data, comprising:

the method comprises the steps that a third node device receives an SF message with signal failure, wherein the SF message is used for indicating that a main link fails, the main link is a link in communication between a first node device and a second node device, the first node device sends first multicast data sent by a multicast source to a client through the main link, the first node device is a node device connected with the multicast source, and the second node device is a node device connected with the client;

a standby link of the main link is further configured between the first node device and the second node device, the main link and the standby link form a loop, the third node device is located on the standby link, the third node device and the first node device can send multicast data in a broadcast mode, and the broadcast mode of the third node device and the broadcast mode of the first node device are in a closed state in a process that the first node device sends the first multicast data to the client through the main link;

the third node device initiating the broadcast mode;

the third node device broadcasts second multicast data received after receiving the SF message until the second multicast data is broadcasted to the second node device, and the second node device sends the second multicast data to the client;

the third node device receives an IGMP query message forwarded by the first node device, wherein the first node device is connected to the multicast source through a routing device, and the IGMP query message is sent by the routing device;

the third node device forwards the IGMP query message to a fourth node device or the second node device; wherein the fourth node device is located between the third node device and the second node device;

the third node device receives a response message corresponding to the IGMP query message sent by the fourth node device or the second node device;

and the third node device sends the response message to the first node device, so that the first node device establishes a new multicast table entry corresponding to the standby link according to the response message, and sends third multicast data sent by the multicast source to the client through the standby link based on the new multicast table entry.

8. The method of claim 7, further comprising:

and after the third node equipment determines that the time length for broadcasting the second multicast data is equal to a preset time length, closing a broadcasting mode of the third node equipment, wherein the first node equipment is connected with the multicast source through a routing equipment, the preset time length is the sum of the interval time length for the routing equipment to send an Internet Group Management Protocol (IGMP) query message to the first node equipment and the time length for the node equipment in the standby link to forward a response message corresponding to the IGMP query message, and the response message is generated by the client.

9. The method of claim 7, wherein after the third node device broadcasts the second multicast data, the method further comprises:

and the third node equipment closes the broadcasting mode of the third node equipment when determining that the failure of the main link is recovered in the process of broadcasting the second multicast data.

10. A first node device comprising a processor and a communication interface, wherein:

the communication interface is used for sending first multicast data sent by a multicast source to a client through a main link under the control of the processor; the main link is a link configured between the first node device and a second node device in advance, the first node device is connected with the multicast source, and the second node device is connected with a client;

the communication interface is further configured to receive, under control of the processor, an SF message indicating that the main link fails, where the SF message is used to trigger the first node device and the at least one third node device to start the broadcast mode; broadcasting second multicast data received after the SF message is received, so that at least one third node device on the standby link continues broadcasting after receiving the second multicast data broadcasted by the first node device until the second multicast data is broadcasted to the second node device, and sending the second multicast data to the client by the second node device;

the communication interface is further configured to receive an IGMP query packet under control of the processor, where the first node device is connected to the multicast source through a routing device, and the IGMP query packet is sent by the routing device;

the communication interface is further configured to forward, under control of the processor, the IGMP query packet to at least one third node device in the backup link, except for the first node device and the second node device;

the communication interface is further configured to receive, under control of the processor, a response message corresponding to the IGMP query message sent by the at least one third node device;

the processor is further configured to establish a new multicast entry corresponding to the backup link according to the response message, and the processor is further configured to control the communication interface to send the third multicast data originated by the multicast to the client through the backup link based on the new multicast entry.

11. The device according to claim 10, wherein the processor is specifically configured to determine, when controlling the communication interface to send first multicast data sent by a multicast source to a client via a main link, that a multicast entry prestored in the first node device is routing information associated with the main link;

the communication interface is used for sending the first multicast data to the client through the main chain based on the multicast table item after receiving the first multicast data.

12. The device of claim 10, wherein the communication interface, under control of the processor, prior to broadcasting the second multicast data, the processor is further configured to:

judging that the received second multicast data meets the condition; wherein the condition is that an initial character string of a destination Media Access Control (MAC) layer address of the second multicast data is a preset character string.

13. The device according to any of claims 10-12, wherein the communication interface is further configured to receive a recovery NR message under control of the processor after broadcasting second multicast data received after receiving the SF message; the NR packet is used to indicate failure recovery in the main link;

the communication interface is further configured to receive a ring network protection switching recovery NRRB message under the control of the processor; the NRRB message is used for indicating a blocking interface in the standby link to be in a blocking state;

the processor is further configured to restart a pre-stored multicast entry, and when the communication interface receives fourth multicast data sent by the multicast source, control the communication interface to send the fourth multicast data to the client through the main link based on the pre-stored multicast entry; and the pre-stored multicast list item is the routing information associated with the main link.

14. The device of claim 10, wherein the processor is further configured to:

and after the time length for broadcasting the second multicast data is determined to be equal to a preset time length, closing a broadcast mode of the first node equipment, wherein the first node equipment is connected with the multicast source through a routing equipment, the preset time length is the sum of the interval time length for the routing equipment to send an Internet Group Management Protocol (IGMP) query message to the first node equipment and the time length for the node equipment in the standby link to forward a response message corresponding to the IGMP query message, and the response message is generated by the client.

15. The device of claim 13, wherein the processor is further configured to:

in the process that the first node device broadcasts the second multicast data through the communication interface, when receiving a recovery NR packet sent by the node device in the main link through the communication interface, closing a broadcast mode of the first node device; wherein the NR packet is used to indicate failure recovery of the main link.

16. A third node device comprising a processor and a communication interface, wherein:

the communication interface receives a Signal Failure (SF) message under the control of the processor, wherein the SF message is used for indicating that a main link fails, the main link is a link in which a first node device and a second node device are communicating, the first node device sends first multicast data sent by a multicast source to a client through the main link, the first node device is a node device connected with the multicast source, and the second node device is a node device connected with the client;

the processor is configured to start a broadcast mode of the third node device after confirming that the communication interface receives the SF message;

the communication interface broadcasts second multicast data received after the SF message is received under the control of the processor until the second multicast data is broadcasted to the second node equipment, and the second node equipment sends the second multicast data to the client;

the communication interface is further configured to receive, under control of the processor, an IGMP query packet forwarded by the first node device, where the first node device is connected to the multicast source through a routing device, and the IGMP query packet is sent by the routing device;

the communication interface is further configured to forward the IGMP query packet to a fourth node device or the second node device under the control of the processor; wherein the fourth node device is located between the third node device and the second node device;

the communication interface is further configured to receive, under control of the processor, a response message corresponding to the IGMP query packet sent by the fourth node device or the second node device;

the processor is further configured to send the response message to the first node device through the communication interface, so that the first node device establishes a new multicast entry corresponding to the backup link according to the response message, and sends third multicast data from the multicast source to the client through the backup link based on the new multicast entry.

17. The device of claim 16, wherein the processor is further configured to:

and after the time length for broadcasting the second multicast data is determined to be equal to a preset time length, closing a broadcasting mode of the third node equipment, wherein the first node equipment is connected with the multicast source through a routing equipment, the preset time length is the sum of the interval time length for the routing equipment to send an Internet Group Management Protocol (IGMP) query message to the first node equipment and the time length for the node equipment in the standby link to forward a response message corresponding to the IGMP query message, and the response message is generated by the client.

18. The device of claim 16, wherein the processor is further configured to:

and in the process of broadcasting the second multicast data by the third node equipment, closing the broadcasting mode of the third node equipment when the fault of the main link is determined to be recovered.

19. A computer-readable storage medium having stored thereon instructions which, when executed on a computer, cause the computer to carry out the method of any one of claims 1-6 or 7-9.