WO2018032869A1

WO2018032869A1 - Method and device for controlling multicast transmission

Info

Publication number: WO2018032869A1
Application number: PCT/CN2017/088654
Authority: WO
Inventors: 杨帆; 王东; 仇普祺
Original assignee: 华为技术有限公司
Priority date: 2016-08-15
Filing date: 2017-06-16
Publication date: 2018-02-22
Also published as: CN106302176A; CN106302176B

Abstract

The present invention relates to the technical field of communications, and disclosed in the embodiments thereof are a method and device for controlling multicast transmission. After a first PE device returns to normal and is promoted to a DR, a second PE device may immediately delete multicast forwarding entries stored in the second PE device, so as to prevent the first PE device and the second PE device forwarding multicast traffic for multicast receivers at the same time. The specific solution is as follows: a second PE device serving as a BDR is promoted to a DR after a failure of a first PE device serving as a DR. The method comprises: after the first PE device returns to normal, the second PE device determining that the first PE device which has returned to normal is promoted to a DR; when determining that the first PE device which has returned to normal is promoted to a DR, sending a first Assert message to the first PE device, the first Assert message being used to obtain information for carrying Assert election from the first PE device which has returned to normal. The embodiments of the present invention are applied to the process of multicast traffic transmission.

Description

Method and device for controlling multicast transmission

This application claims the priority of the Chinese patent application filed on August 15, 2016, the Chinese Patent Office, the application number is CN 201610674380.6, and the invention is entitled "A method and device for controlling multicast transmission". The citations are incorporated herein by reference.

Technical field

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

Background technique

In the multicast technology, different users' private networks can be connected through the carrier's backbone network. Specifically, the backbone network can communicate with the multicast receiver in the private network through the Provider Edge (PE) device. The PE device that communicates with the multicast receiver can receive the multicast traffic from the multicast source and forward the multicast traffic to the multicast receiver in the private network according to the multicast forwarding entry.

In order to avoid the abnormal transmission of multicast traffic caused by the failure of the PE device that communicates with the multicast receiver, two PE devices that communicate with the multicast receiver are usually set up. The two PE devices include: as the designated router (English: Designated Router) , PE device 1 for short: DR) and PE device 2 for backup designated router (BDR). The PE device 1 as a DR and the PE device 2 as a BDR communicate with a multicast receiver through a Layer 2 switch. After the PE device 1 that is the DR is faulty, the PE device 2 that is the BDR is upgraded to the DR. After the multicast forwarding entry is obtained, the Layer 2 switch forwards the multicast traffic. After the faulty PE device 1 is restored, the normal PE device 1 is upgraded to the DR. After the multicast forwarding entry is obtained, the Layer 2 switch forwards the multicast traffic. When the normal PE device is upgraded to DR, the PE device 2 is reduced from DR to BDR. The periodic suppression mechanism set on the PE device 2 of the BDR is such that the PE device 2 determines whether the downstream interface of the PE device 2 receives the multicast traffic during the detection period. If the PE device 1 as the DR returns to normal within the detection period and sends multicast traffic through its downstream interface, the PE device 2 initiates an assertion (English: Assert) election after the end of the detection period. The PE device 2 deletes the multicast forwarding entry on the PE device 2 after the Assert election fails. Therefore, in the detection period, even after the PE device 1 returns to normal, the PE device 2 still forwards the multicast traffic according to the multicast forwarding entry, and the multicast receiver receives the PE device from the BDR through the Layer 2 switch. And the double multicast traffic of the PE device 1 as the DR.

Summary of the invention

The present invention provides a method and device for controlling multicast transmission, which helps to prevent multicast receivers from receiving double multicast traffic and saving network resources.

In order to achieve the above object, the present invention adopts the following technical solutions:

The first aspect provides a method for controlling multicast transmission. The second PE device that is the BDR is upgraded to the DR after the first PE device that is the DR is faulty. The method for controlling the multicast transmission includes: After the first PE device returns to normal, the second PE device determines that the first PE device that is restored to normal is upgraded to the DR; and the second PE device determines that the first PE device that is restored to normal is When the DR is the DR, the first Assert message is sent to the first PE device, where the first Assert message is used to obtain information about the Assert election from the first PE device that is restored to normal.

If the first PE device returns to normal in a detection period of the period suppression mechanism, the second PE device cannot detect the group of the downstream interface of the second PE device in real time before the end of the detection period. Broadcast traffic. However, the second PE device may send the first Assert message to the first PE device to obtain the first PE device that is restored from normal when the first PE device that is restored to be normal is upgraded to the DR. Assert election information. After the second PE device is elected to the BDR by the Assert election, the second PE device immediately deletes the multicast forwarding entry saved in the second PE device, and the first PE device and the second device are avoided. The PE device forwards multicast traffic to multicast receivers at the same time.

In a possible implementation manner, after the first PE device returns to normal, the determining, by the second PE device, that the returning the normal first PE device to be the DR includes: the second PE device receiving the Returning the DR election message sent by the first first PE device, where the DR election message carries the DR election information of the first PE device that is restored to normal; the second PE device is restored according to the normal The DR election information of the PE device and the DR election information of the second PE device are used for the DR election. The second PE device determines that the first PE device that is restored to normal is upgraded to the DR according to the result of the DR election. The DR election information of the first PE device that is restored to normal may include the DR priority of the first PE device that is restored to normal and/or the Internet protocol of the downstream interface of the first PE device that is restored to the normal state. : Internet Protocol, referred to as: IP) address. The DR election information of the second PE device may include a DR priority of the second PE device and/or an IP address of a downstream interface of the second PE device.

The normal period suppression mechanism can only suppress the real-time perception of service packets (multicast traffic) of the downstream interface of the second PE device in the detection period. The normal period suppression mechanism does not suppress the real-time perception of protocol packets by the downstream interface of the second PE device during the detection period. The DR election message sent by the first PE device to the second PE device belongs to the protocol packet. Therefore, the second PE device can determine, by using its downstream interface, the DR election message received from the first PE device that is restored to be normal. The second PE device performs DR election according to the DR election message, and performs a corresponding Assert election after determining that the first PE device is promoted to a DR.

In a possible implementation, after the first PE device returns to the normal state, determining that the first restored PE device is upgraded to the DR includes: the second PE device detecting the The downstream interface of the second PE device is switched from the first state to the second state, and it is determined that the first PE device that is restored to normal is upgraded to the DR. The first state is a state in which the downstream interface of the second PE device does not receive the multicast traffic, and the second state is a state in which the downstream interface of the second PE device receives the multicast traffic. The downstream interface of the second PE device is an interface capable of communicating with a multicast receiver.

The first PE device does not forward multicast traffic after being used as the BDR. After the first PE device functions as a DR, multicast traffic is forwarded. If the downstream interface of the second PE device does not receive the multicast traffic, the first PE device is a BDR. If the downstream interface of the second PE device receives the multicast traffic, the first PE device is upgraded from the BDR to the DR. Therefore, in a case where the downstream interface of the second PE device is converted from the state in which the multicast traffic is not received to the received multicast traffic, the second PE device may determine that the first PE device is restored to normal and is up. For DR.

In a possible implementation manner, the multicast traffic may be the multicast traffic that is sent by the first PE device that is restored to the first time by the downstream interface of the first PE device that is restored to the normal state. The first time is the time when the first PE device that is in the normal state of the fault is restored to the normal time, and the preset time length is greater than or equal to the aging time of the periodic suppression mechanism, and the normalized first PE device is downstream. The interface is capable of communicating with the multicast receiver. interface.

In the case that the first PE device that is restored to normal is upgraded to the DR, the first PE device that returns to normal does not immediately forward the multicast traffic. After the aging time of the periodic suppression mechanism arrives, the first PE device that returns to normal sends multicast traffic through the downstream interface of the first PE device. After the aging time of the period suppression mechanism arrives, the period suppression mechanism of the second PE device fails. Therefore, the second PE device can detect the multicast traffic of the downstream interface in real time, so that the second PE device immediately sends the first Assert packet to the first PE device. In this way, the second PE device can immediately delete the multicast forwarding entry saved in the second PE device, and prevent the first PE device and the second PE device from simultaneously forwarding multicast traffic for the multicast receiver.

In a possible implementation manner, the method provided by the embodiment of the present invention may further include: the second PE device receiving the second Assert message sent by the first PE device that is restored to normal, the second Assert report The file includes Assert election information of the first PE device, and the second PE device performs Assert election according to the Assert election information of the first PE device and the Assert election information of the second PE device; the second PE device After the Assert election fails, the multicast forwarding entry saved by the second PE device is deleted.

The first Assert message is used to obtain information about an Assert election from the first PE device that is restored to normal. After receiving the first Assert message, the first PE device sends the Assert election information of the first PE device to the second PE device, for example, sending an Assert including the first PE device. Electing a second Assert message of the information, so that the second PE device performs an Assert election.

The Assert election information of the first PE device may include: a unicast routing protocol priority of the first PE device and/or an IP address of a downstream interface of the first PE device. The Assert election information of the second PE device may include: a unicast routing protocol priority of the second PE device and/or an IP address of a downstream interface of the second PE device.

In a second aspect, a method for controlling multicast transmission is provided. The second PE device that is the BDR is upgraded to the DR after the first PE device that is the DR is faulty. The method for controlling the multicast transmission includes: After the faulty first PE device returns to the normal state, it is determined that the DR device is upgraded to the DR. After the first PE device that obtains the normality obtains the multicast forwarding entry, the first PE device sends the first Assert packet to the second PE device. The first Assert message is used to instruct the second PE device to perform an Assert election.

The second PE device cannot detect the multicast traffic of the downstream interface in real time during the detection period in the case that the first PE device returns to normal in a detection period of the period suppression mechanism. The second PE device can receive the first Assert message in real time through the downstream interface. Therefore, after obtaining the multicast forwarding entry, the first PE device sends the first Assert packet to the second PE device, so that the second PE device receives the first Assert packet. The Assert election can be performed immediately, and then the multicast forwarding entry saved in the second PE device is deleted after the Assert election fails, so that the first PE device and the second PE device can be prevented from being simultaneously received by the multicast device. Forward multicast traffic.

In a possible implementation manner, after the faulty first PE device returns to normal and then rises to the DR, and the first PE device that returns to normal sends the first Assert report to the second PE device. The method provided by the embodiment of the present invention may further include: the first PE device that returns to normal sends a DR election message to the second PE device, where the DR election message includes the first PE device The DR election information includes the DR priority of the first PE device and/or the IP address of the downstream interface of the first PE device.

The first PE device that returns to normal is in the second detection period of the period suppression mechanism. The PE device sends the DR election message. The second PE device can perceive the DR election message of its downstream interface in real time, because the periodic suppression mechanism does not suppress the sensing of the non-service packets received during the detection period. After the second PE device determines that the first PE device that has returned to normal is upgraded to the DR according to the DR election result, the second PE device may send the second Assert message to the first PE device, so that the second PE device performs the Assert election.

In a possible implementation manner, after the returning normal first PE device obtains the multicast forwarding entry, the method provided by the embodiment of the present invention may further include: the restoring the normal first PE device by using the The downstream interface of the first PE device that has returned to normal sends multicast traffic, and the downstream interface of the first PE device that is restored to normal is an interface that can communicate with the multicast receiver. As the multicast traffic of the downstream interface of the second PE device changes from scratch, the second PE device can perform an Assert election, so that the saved multicast forwarding entry can be deleted immediately, and the present invention does not exist. The first PE device and the second PE device simultaneously forward multicast traffic for the multicast receiver.

In a possible implementation manner, after the returning normal first PE device obtains the multicast forwarding entry, the method provided by the embodiment of the present invention further includes: the first PE device that is restored to be normal at the first moment Send multicast traffic through its downstream interface. The first time is a time after the preset time period of the fault that the first PE device returns to normal. The preset duration is greater than or equal to the aging time of the periodic suppression mechanism. The downstream interface of the first restored PE device is an interface capable of communicating with a multicast receiver.

The cycle suppression mechanism of the second PE device has failed at the first moment. If the downstream interface of the first PE device sends the multicast traffic at the first moment, the second PE device can perceive the multicast traffic of the downstream interface in real time. In this manner, the second PE device can initiate an Assert election after the multicast traffic of the downstream interface is detected, and immediately delete the multicast forwarding entry saved in the second PE device, thereby avoiding the first PE device and the The second PE device forwards multicast traffic to the multicast receiver at the same time.

In the method provided by the foregoing second aspect or any one of the foregoing possible implementation manners, the first PE device that is restored to normal may be used as a device that triggers an Assert election, that is, the first PE device that is restored to normal may be in the foregoing After the multicast forwarding entry is obtained, the first Assert election message is sent to the second PE device. Optionally, the first Assert election message may be used as the response message of the second Assert election message from the second PE device, that is, the first PE device that returns to normal sends the first message to the second PE device. Before the Assert message, the method provided by the embodiment of the present invention further includes: the first PE device receives a second Assert message from the second PE device, where the second Assert message is used to resume normal from the The first PE device obtains information for the Assert election.

A third aspect provides a method for controlling multicast transmission, where the method for controlling multicast transmission includes: obtaining, by a second PE device that is a BDR, a first multicast forwarding entry, and saving the first The multicast forwarding entry includes a flag bit, and the flag bit is used to indicate that the first multicast forwarding entry cannot be used to forward the multicast traffic received by the upstream interface of the second PE device. The first multicast forwarding entry is not deleted after the second PE device is reduced from the DR to the BDR.

Optionally, after the second PE device is upgraded to the DR, the second multicast forwarding entry is obtained, where the second multicast forwarding entry is used to forward the multicast traffic received by the upstream interface of the second PE device. The second multicast forwarding entry is absent from the first multicast forwarding entry, and the second multicast forwarding entry and other content of the first multicast forwarding entry are absent. the same.

The marking bit in the first multicast forwarding entry indicates that the first multicast forwarding entry cannot be used to forward the multicast traffic received by the upstream interface of the second PE device. Therefore, even if the upstream interface of the second PE device that is the BDR receives the multicast traffic, the multicast traffic cannot be forwarded according to the first multicast forwarding entry. In this way, pre-storing the first multicast forwarding entry in the second PE device does not cause the second PE device that is the BDR and the first PE device that is the DR. At the same time, multicast traffic is forwarded for multicast receivers. Further, the first multicast forwarding entry does not enable the periodic suppression mechanism after the second PE device that is the BDR receives the multicast traffic on its downstream interface. The second PE device that is reduced from the DR to the BDR can sense the multicast traffic of the downstream interface in real time and initiate the Assert election. In this way, the second PE device can immediately delete the second multicast forwarding entry, which can prevent the second PE device and the first PE device from forwarding multicast traffic for the multicast receiver at the same time.

In a fourth aspect, a second PE device is provided, and the second PE device that is the BDR is upgraded to a DR after the first PE device that is the DR is faulty, and the second PE device includes: a determining unit and a sending unit. The determining unit is configured to determine that the first PE device that is restored to normal is upgraded to the DR after the first PE device returns to normal. The sending unit is configured to: when the determining unit determines that the first PE device that is restored to be normal is upgraded to the DR, send the first Assert message to the first PE device, where the first Assert message is sent And obtaining information for performing an Assert election from the first PE device that is restored to normal.

In a possible implementation, the determining unit may include: a receiving subunit, a DR electing subunit, and a determining subunit. The receiving subunit is configured to receive the DR election message sent by the first PE device that is restored to the normal state, where the DR election message carries the DR election information of the first PE device that is restored to normal. The DR election information of the first PE device that is restored to the normal state includes the DR priority of the first PE device that is restored to the normal state and/or the IP address of the downstream interface of the first PE device that is restored to the normal state. The DR election sub-unit is configured to perform DR election according to the DR election information of the first PE device that is restored and the DR election information of the second PE device that is received by the receiving sub-unit, and the second The DR election information of the PE device includes the DR priority of the second PE device and/or the IP address of the downstream interface of the second PE device. The determining subunit is configured to determine, according to the result of the DR election obtained by the DR election in the DR election subunit, that the first PE device that is restored to normal is upgraded to the DR.

In a possible implementation manner, the determining unit is configured to: detect that the downstream interface of the second PE device is switched from the first state to the second state, and determine that the first PE device that is restored to normal For the DR. The first state is a state in which the downstream interface of the second PE device does not receive the multicast traffic, and the second state is a state in which the downstream interface of the second PE device receives the multicast traffic, where the The downstream interface of the second PE device is an interface that can communicate with the multicast receiver.

In a possible implementation manner, the multicast traffic may be a multicast traffic that is sent by the first PE device that is restored to the first time by the downstream interface of the first PE device that is restored to the normal state. The first time is the time after the time when the faulty first PE device returns to normal, and the preset time length is greater than or equal to the aging time of the cycle suppression mechanism. The downstream interface of the first PE device that is restored to normal is an interface that can communicate with the multicast receiver.

In a possible implementation, the second PE device in the foregoing fourth aspect may further include: a receiving unit, an assertion election unit, and an entry deletion unit. The receiving unit is configured to receive the second Assert message sent by the first PE device that is restored to the normal state, where the second Assert message includes the Assert election information of the first PE device. The assertion election unit is configured to perform an Assert election according to the Assert election information of the first PE device and the Assert election information of the second PE device received by the receiving unit. The entry deletion unit is configured to delete the multicast forwarding entry saved by the second PE device after the Assert election of the assertion election unit fails.

The functional units of the fourth aspect and various possible implementation manners of the embodiments of the present invention are used to perform multicast transmission according to the foregoing first aspect and various alternative manners of the first aspect. Method, and logical division of the second PE device. Detailed description of each functional unit of the fourth aspect and its various possible implementations For the description of the beneficial effects, reference may be made to the corresponding descriptions and technical effects in the foregoing first aspect and various possible implementation manners, and details are not described herein again.

According to a fifth aspect, a first PE device is provided, and the second PE device that is the BDR is upgraded to the DR after the first PE device that is the designated router DR is faulty, and the first PE device includes: a determining unit and a sending unit. . The determining unit is configured to determine that the first PE device is upgraded to the DR after the faulty first PE device returns to normal. The sending unit is configured to send, after the determining unit, the first PE device to the DR and obtain the multicast forwarding entry, send the first Assert message to the second PE device, where the first Assert The packet is used to instruct the second PE device to perform an Assert election.

In a possible implementation, the sending unit, in the foregoing fifth aspect, is further configured to: after the determining unit determines that the first PE device is upgraded to a DR, the sending unit sends the second PE to the second PE Before sending the first Assert packet, the device sends a DR election message to the second PE device. The DR election message includes the DR election information of the first PE device, and the DR election information of the first PE device includes the DR priority of the first PE device and/or the downstream interface of the first PE device. IP address.

In a possible implementation, the sending unit, which is used in the foregoing fifth aspect or the possible implementation manner of the fifth aspect, is further configured to obtain a multicast forwarding in the first PE device that is also used to restore the normal After the item is published, the downstream interface of the first PE device that is restored to normal is configured to send multicast traffic, and the downstream interface of the first PE device that is restored to normal is an interface that can communicate with the multicast receiver.

In a possible implementation, the sending unit, which is used in the foregoing fifth aspect or the possible implementation manner of the fifth aspect, is further configured to obtain a multicast forwarding in the first PE device that is also used to restore the normal After the item is published, the multicast interface is sent to the downstream interface of the first PE device that is restored to the normal state, and the downstream interface of the first PE device that is restored to normal is an interface capable of communicating with the multicast receiver. The first time is the time after the time when the faulty first PE device returns to normal, and the preset time length is greater than or equal to the aging time of the cycle suppression mechanism.

The functional units of the fifth aspect of the embodiments of the present invention and various possible implementation manners thereof are used to perform multicast transmission according to the foregoing second aspect and various alternative manners of the second aspect. Method, while logically dividing the first PE device. For a detailed description of the various functional units of the fifth aspect and its various possible implementations, and the beneficial effects analysis, reference may be made to the corresponding descriptions and technical effects in the foregoing second aspect and various possible implementation manners, and details are not described herein again.

According to a sixth aspect, a second PE device is provided, and the second PE device that is the BDR is upgraded to the DR after the first PE device that is the DR is faulty, and the second PE device includes: an acquiring unit and a storage unit. The obtaining unit is configured to obtain a first multicast forwarding entry. The storage unit is configured to save the first multicast forwarding entry obtained by the acquiring unit. The first multicast forwarding entry includes a flag bit, and the flag bit is used to indicate that the first multicast forwarding entry cannot be used to forward the multicast traffic received by the upstream interface of the second PE device. The first multicast forwarding entry is not deleted after the second PE device is reduced from the DR to the BDR.

In a possible implementation manner, the acquiring unit is further configured to: after the second PE device is upgraded to the DR, obtain the second multicast forwarding entry, where the second multicast forwarding entry is used to forward the first The multicast traffic received by the upstream interface of the PE device. The second multicast forwarding entry is absent from the first multicast forwarding entry, and the second multicast forwarding entry and other content of the first multicast forwarding entry are absent. the same.

The functional units in the sixth aspect of the embodiments of the present invention are for performing the method for controlling multicast transmission according to the foregoing third aspect, and performing logical division on the second PE device. For a detailed description and beneficial effect analysis of each functional unit in the sixth aspect, reference may be made to the corresponding description and technical effects in the foregoing third aspect, I won't go into details here.

According to a seventh aspect, a second PE device is provided, wherein the second PE device that is the BDR is promoted to the DR after the first PE device device that is the DR fails. The second PE device includes a processor, a memory, a bus, and a communication interface. The memory is configured to store a computer to execute instructions, the processor is coupled to the memory via a bus, and when the second PE device is in operation, the processor executes the computer-executed instructions stored in the memory to cause the The second PE device performs the method for controlling multicast transmission as described in the first aspect and various alternatives of the first aspect.

In an eighth aspect, a nonvolatile storage medium is provided, wherein the nonvolatile storage medium stores one or more program codes, and the processor of the second PE device described in the seventh aspect executes the program At the time of the code, the second PE device performs the method for controlling multicast transmission as described in the first aspect and the various alternatives of the first aspect.

The processor described in the seventh aspect may be the integration of the determining unit, the asserting election unit, and the entry deleting unit, which are described in the fourth aspect and various possible implementation manners thereof, where the seventh aspect is The communication interface may be the integration of the sending unit and the receiving unit in the fourth aspect and various possible implementation manners thereof, and is used to implement the second PE device and other communication devices (such as the first PE device and multicast receiving). Information exchange between the person or the upstream routing device. The specific technical effects of the second PE device and the second PE device in the computer-readable storage medium described in the eighth aspect, and the related analysis process may refer to the first aspect of the embodiments of the present invention. The related technical effects description in any implementation manner of the first aspect is not described herein again.

According to a ninth aspect, a first PE device is provided, wherein the second PE device that is the BDR is promoted to the DR after the first PE device device that is the DR fails. The first PE device includes a processor, a memory, a bus, and a communication interface. The memory is configured to store a computer to execute instructions, the processor is coupled to the memory via a bus, and when the first PE device is in operation, the processor executes the computer-executed instructions stored in the memory to cause the The first PE device performs the method for controlling multicast transmission as described in the second aspect and various alternatives of the second aspect.

According to a tenth aspect, a nonvolatile storage medium is provided, wherein the nonvolatile storage medium stores one or more program codes, and the processor of the first PE device described in the ninth aspect executes the program At the time of the code, the first PE device performs the method for controlling multicast transmission as described in the second aspect and various alternatives of the second aspect.

The processor in the ninth aspect may be the integration of the functional unit such as the determining unit in the fifth aspect and various possible implementation manners, and the communication interface in the ninth aspect may be the foregoing fifth The integration of the transmitting unit and the receiving unit described in the aspects and various possible implementation manners thereof for implementing between the first PE device and other communication devices (such as the second PE device, the multicast receiver, or the upstream routing device) Information interaction. The specific technical effect of the first PE device and the first PE device in the computer-readable storage medium described in the ninth aspect, and the related analysis process may refer to the second embodiment of the present invention. Description of related art effects in aspects or implementations of any of the second aspects, and details are not described herein again.

In an eleventh aspect, a second PE device is provided, wherein the second PE device that is the BDR is promoted to the DR after the first PE device device that is the DR fails. The second PE device includes a processor, a memory, a bus, and a communication interface. The memory is configured to store a computer to execute instructions, the processor is coupled to the memory via a bus, and when the second PE device is in operation, the processor executes the computer-executed instructions stored in the memory to cause the The second PE device performs the method for controlling multicast transmission as described in the third aspect and various alternatives of the third aspect.

According to a twelfth aspect, a nonvolatile storage medium is provided, wherein the nonvolatile storage medium stores one or more program codes, which are executed by a processor of the second PE device described in the eleventh aspect The program code, the second The PE device performs the method for controlling multicast transmission as described in the third aspect and various alternatives of the third aspect.

The processor in the eleventh aspect may be the integration of the function unit, such as the acquiring unit, in the sixth aspect, and the memory in the eleventh aspect may be the storage unit in the sixth aspect. . The specific technical effect of the second PE device and the second PE device in the computer-readable storage medium described in the twelfth aspect, and the related analysis process may refer to the embodiment of the present invention. Description of related technical effects in any of the three aspects or the third aspect, and details are not described herein again.

DRAWINGS

FIG. 1 is a schematic diagram of a network architecture of a multicast network according to an embodiment of the present disclosure;

2 is a schematic diagram of a network architecture of another multicast network according to an embodiment of the present invention;

3 is a schematic diagram of state switching of a primary and backup PE device;

FIG. 4 is a flowchart of a method for controlling multicast transmission according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a format of a packet header of a PIM packet according to an embodiment of the present disclosure;

FIG. 6 is a flowchart of another method for controlling multicast transmission according to an embodiment of the present invention;

FIG. 7 is a flowchart of another method for controlling multicast transmission according to an embodiment of the present invention;

FIG. 8 is a flowchart of another method for controlling multicast transmission according to an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of a second PE device according to an embodiment of the present disclosure;

FIG. 10 is a schematic structural diagram of another second PE device according to an embodiment of the present disclosure;

FIG. 11 is a schematic structural diagram of another second PE device according to an embodiment of the present disclosure;

FIG. 12 is a schematic structural diagram of another second PE device according to an embodiment of the present disclosure;

FIG. 13 is a schematic structural diagram of a first PE device according to an embodiment of the present disclosure;

FIG. 14 is a schematic structural diagram of another first PE device according to an embodiment of the present invention.

detailed description

The terms "first" and "second" and the like in the description of the present invention and the drawings are used to distinguish different objects, or to distinguish different processing of the same object, rather than to describe a specific order of the objects. For example, the first PE device and the second PE device may be different PE devices. The first Assert message and the second Assert message may be different Assert messages.

In the description of the present invention, the meaning of "a plurality" means two or more unless otherwise indicated. For example, a multi-core processor refers to a processor that contains two or more physical cores.

Furthermore, the terms "comprises" and "comprising" and variations of the invention, as used in the description of the invention, are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or device that comprises a series of steps or units is not limited to the listed steps or units, but optionally includes other steps or units not listed, or alternatively Other steps or units inherent to these processes, methods, products or devices are included.

The method for controlling the multicast transmission provided by the embodiment of the present invention may be applied to the process of transmitting the multicast traffic, and may be applied to the second PE device as the BDR after the failure of the first PE device as the DR. In the scenario of multicast transmission after DR.

Please refer to FIG. 1 , which is a schematic diagram of a network architecture of a multicast network applied to a method for controlling multicast transmission according to an embodiment of the present invention.

As shown in FIG. 1, the multicast network may include an operator's backbone network 10 and a plurality of user private networks. The plurality of The user private network may include the user private network 20, the user private network 30, and the user private network 40 in FIG. The backbone network 10 includes an operator (English: provider, referred to as: P) device 11 and a plurality of provider edge (PE) devices. The plurality of PE devices may include the PE device 12, the PE device 13, and the PE device 14 in FIG. Each user's private network includes a user edge (English: customer edge, referred to as: CE) device. As shown in FIG. 1, the user private network 20 includes a CE device 21, and the CE device 21 communicates with the PE device 12. The user private network 30 includes the CE device 31, and the CE device 31 communicates with the PE device 13. The user private network 40 includes the CE device 41, and the CE device 41 communicates with the PE device 14.

Any one of the foregoing CE devices may be a router or a switch that connects to the user host, or any one of the CE devices may be a user host or a server in the private network of the user. As shown in FIG. 1 , the network architecture of the multicast network to which the embodiment of the present invention is applied is described by using the CE device 21 as a router or a switch connected to the user host. The device in the user private network 20 to which the CE device 21 is connected requests and receives multicast traffic. The CE device 21 can be regarded as a multicast receiver in the embodiment of the present invention.

In order to avoid abnormal transmission of multicast traffic caused by the failure of the PE device 12 communicating with the multicast receiver, the PE device 22 can be configured with the backup PE device 22. As shown in FIG. 2, the PE device 22 is a backup device of the PE device 12. The CE device 21 can be dual-homed to the PE device 12 and the PE device 22 through the Layer 2 switch of FIG. The CE device 22 can be dual-homed to the PE device 12 and the PE device 22 through the Layer 2 switch of FIG.

When the PE device 12 is normal, the PE device 12 acts as a DR, and performs multicast traffic forwarding according to the multicast forwarding entry saved. The PE device 22 is configured as a BDR. The multicast forwarding entry is not saved in the PE device 22. The multicast traffic cannot be forwarded. The PE device 12 acts as a DR and the PE device 22 acts as a BDR from the time t1 shown in FIG. 3 until the time t4. If the PE device 12 that is the DR fails at time t4 shown in FIG. 3, the PE device 12 that is the DR cannot forward the multicast traffic. The PE device 12 drops to the BDR at time t4, and deletes the multicast forwarding entry that it holds. From the time t4 shown in FIG. 3 until the time t5 when the PE device 12 returns to normal, the PE device 12 acts as a BDR and the PE device 22 acts as a DR. After being upgraded to the DR, the PE device 22 acquires and saves the multicast forwarding entry, and forwards the multicast traffic according to the saved multicast forwarding entry. At time t5 shown in FIG. 3, the PE device 12 returns to normal. Starting from time t5 shown in FIG. 3, the normal PE device 12 is upgraded to DR, and the PE device 22 is reduced to BDR. The normalized PE device 12 acquires and saves the multicast forwarding entry, and forwards the multicast traffic according to the saved multicast forwarding entry. If the PE device 22 does not enable the period suppression mechanism, the PE device 22 that is the BDR may initiate an Assert election after determining that the downstream interface receives the multicast traffic. The PE device 22 deletes the multicast forwarding entry saved in the PE device 22 after the Assert election fails. The DR and BDR switching performed between the PE device 12 and the PE device 22 is implemented by DR election. For the specific method for the DR device 12 and the PE device 22 to perform DR election, refer to the present invention. A description of the embodiments follows.

During the period of t1-t4 shown in FIG. 3, the downstream interface of the PE device 22 can receive the multicast traffic forwarded by the PE device 12 through the Layer 2 switch. Since the PE device 22 as the BDR does not store the multicast forwarding entry for forwarding the multicast traffic, the PE device 22 as the BDR frequently receives the multicast traffic to its central processor ( English: Central Processing Unit (referred to as: CPU) reports missing (miss) messages. The miss message is used to indicate that the forwarding entry is lost. In order to avoid the impact of a large number of miss messages on the CPU of the PE device 22 as the BDR, the PE device 22 as the BDR may receive multicast traffic on its downstream interface and the PE device 22 does not exist for forwarding the multicast. In the case of multicast forwarding entries for traffic, the period suppression mechanism is enabled.

Based on the above description, the downstream interface of the PE device 22 may receive multicast traffic during the period of t1-t4, for example, the downstream interface of the PE device 22 receives the multicast traffic at time t2. The downstream interface of the PE device 22 receives the multicast traffic at the time t2, because the multicast forwarding entry that can be used to forward the multicast traffic is not saved in the PE device 22 during the period of t1-t4. The PE device 22 can then enable the cycle suppression mechanism. As shown in FIG. 3, if the detection period of the period suppression mechanism is X, the PE device 22 ends the detection period of the period suppression mechanism at time t3, that is, the period t2-t3 is one detection period. After the PE device 22 enables the period suppression mechanism at time t2, even if the downstream interface of the PE device 22 receives the multicast traffic during the period t2-t3, the PE device 22 does not send the multicast traffic to its CPU in real time after receiving the multicast traffic. The miss message is reported, but the miss message is received after receiving the multicast traffic during the period t2-t3 at time t3. The PE device 22 may perform periodic detection according to X before the aging time of the periodic suppression mechanism arrives. The aging time of the cycle inhibition mechanism is Y.

After the periodicity suppression mechanism is enabled, the PE device 22 fails to receive multicast traffic within the aging time Y of the periodic suppression mechanism, and the periodic suppression mechanism fails. The PE device 22 can detect whether the downstream interface receives the multicast traffic in real time after the period suppression mechanism fails. The aging time Y of the periodic suppression mechanism is greater than the detection period X of the periodic inhibition mechanism. In the case that the downstream interface of the PE device 22 receives the multicast traffic in the detection period corresponding to t2-t3, the PE device 22 refreshes the cycle suppression mechanism at time t3, that is, the aging time Y of the cycle suppression mechanism. The calculation time becomes the time t3. The PE device 22 starts to detect multicast traffic during the period t3-t6. Among them, t3-t6 corresponds to one detection period. The detection period corresponding to t3-t6 is the next detection period of the detection period corresponding to t2-t3. The PE device 22 determines that its downstream interface has not received multicast traffic during the time Y of t3-t7, and the PE device 22 can determine that the cycle suppression mechanism is invalid.

After the PE device 22 refreshes the cycle suppression mechanism at time t3, the PE device 12 returns to normal at time t5 and is promoted to a DR by the BDR. The downstream interface of the PE device 22 may receive multicast traffic from the PE device 12 forwarded by the Layer 2 switch starting from time t5. Based on the above description, the period suppression mechanism of the PE device 22S is in an active state during the period t3-t6. Therefore, during the period of t5-t6, the PE device 22 cannot perceive the multicast traffic of its downstream interface in real time. The PE device 22 will not initiate an Assert election during the period of t5-t6. During the period of t5-t6, the PE device 22 still uses the saved multicast forwarding entry to send the multicast traffic to the Layer 2 switch. In this way, the CE device 12 receives two identical multicast traffic from the PE device 12 and the PE device 22 through the Layer 2 switch.

In order to solve the problem that the multicast receiver mentioned in the foregoing solution receives two identical multicast traffic, the embodiment of the present invention provides a method and device for controlling multicast transmission. In the solution provided by the embodiment of the present invention, the interaction between the PE device 22 and the PE device 12 through the protocol packet triggers the PE device 22 to initiate an Assert election immediately after determining that the PE device 12 is upgraded to a DR. In this way, the PE device 22 can delete the multicast forwarding entry that it saves, and the PE device 12 and the PE device 22 can prevent the multicast receiver from forwarding multicast traffic at the same time.

For example, if the PE device 12 fails to forward the multicast traffic, the device may fail to forward the multicast traffic to the Layer 2 switch through the downstream interface. Or the PE device 12 fails to perform the forwarding of the multicast traffic, and the link between the PE device 12 and the Layer 2 switch is faulty, so that the Layer 2 switch cannot receive the PE device 12 to send. Multicast traffic.

For example, the multicast forwarding entry in the embodiment of the present invention may include a backbone network multicast forwarding entry and a private network multicast forwarding entry. For the method for obtaining the foregoing multicast forwarding entry, the PE device 12 or the PE device 22 can refer to the method for obtaining the multicast forwarding entry, which is not described herein again.

The DR and BDR switching performed between the PE device 12 and the PE device 22 is implemented by DR election. The PE device 12 and the PE device 22 in the embodiment of the present invention may use a Protocol Independent Multicast (PIM) protocol. The PE device 12 and the PE device 22 can perform DR election by using Hello packets. The PE device 12 sends a Hello packet carrying the DR priority of the PE device 12 to the PE device 22. The PE device 22 compares the DR priority of the PE device 12 and the DR priority of the PE device 22 carried in the Hello packet. If the DR priority of the PE device 12 is higher than the DR priority of the PE device 22, the PE device 22 fails in the DR election. If the DR priority of the PE device 12 is lower than the DR priority of the PE device 22, the PE device 22 wins in the DR election. The device that failed in the DR election acts as a BDR. In the embodiment of the present invention, the DR priority of the PE device 12 is higher than the DR priority of the PE device 22. If the PE device 22 performs DR election, the PE device 12 is a DR, and the PE device is a DR device. 22 is the BDR.

Optionally, the Hello packet sent by the PE device 12 may further include an IP address of a downstream port of the PE device 12. If the PE device 12 and the PE device 22 do not support the DR election based on the DR priority, or the DR priority of the PE device 12 and the DR priority of the PE device 22 are the same, the PE device 22 may The IP address of the downstream interface of the PE device 12 and the IP address of the downstream interface of the PE device 22 are further compared. If the IP address of the downstream interface of the PE device 12 is greater than the IP address of the downstream interface of the PE device 22, the PE device 22 fails in the DR election; if the IP address of the downstream interface of the PE device 12 is smaller than The IP address of the downstream interface of the PE device 22, the PE device 22 wins in the DR election. In the embodiment of the present invention, the IP address of the downstream interface of the PE device 12 is greater than the IP address of the downstream interface of the PE device 22. If the PE device 22 performs DR election, the PE device 12 is a DR. The PE device 22 is a BDR.

In the embodiment of the present invention, the PE device 12 is a first PE device, and the PE device 22 is a second PE device. The method and device for controlling multicast transmission are described in detail. As shown in any of FIG. 4 and FIG. 6 to FIG. 9, the method for controlling multicast transmission may include:

S101. The first PE device and the second PE device perform DR election. The first PE device is elected as a DR, and the second PE device is elected as a BDR.

For the specific method for the DR election of the first PE device and the second PE device, reference may be made to the foregoing description of the embodiments of the present invention.

S102. The second PE device that is the BDR starts the cycle suppression mechanism after receiving the multicast traffic on the downstream interface.

The principle and method for starting the period suppression mechanism after the second PE device as the BDR receives the multicast traffic on the downstream interface can refer to the foregoing description of the embodiments of the present invention.

S103: After the first PE device that is the DR is faulty, delete the multicast forwarding entry saved in the first PE device.

S104: The second PE device that is the BDR is upgraded to the DR after the failure of the first PE device that is the DR, obtains a multicast forwarding entry, and receives the multicast forwarding entry through the downstream interface according to the multicast forwarding entry. The sender sends the multicast traffic received by its upstream interface.

The downstream interface of the second PE device is an interface capable of communicating with a multicast receiver. The upstream interface of the second PE device is an interface capable of receiving multicast traffic sent by the multicast source. The second PE device as the BDR is promoted to the DR after the failure of the first PE device as the DR, and the first PE device is reduced to the BDR. For example, the method for the second PE device that is the BDR to determine the fault of the first PE device that is the DR may use a common fault detection method, which is not described herein again.

The second PE device that is upgraded to the DR can obtain the multicast forwarding entry according to the multicast forwarding entry. The downstream interface sends multicast traffic received by its upstream interface to the multicast receiver. The downstream interface of the second PE device that is promoted to the DR is an interface that can communicate with the multicast receiver.

In the first application scenario of the embodiment of the present invention, as shown in FIG. 4, after S104, the method provided by the embodiment of the present invention may further include S201-S209:

S201: After the first PE device returns to normal, the device sends a DR election message to the second PE device, where the DR election message carries the DR election information of the first PE device that is restored.

For example, the DR election information of the first PE device that is restored to normal includes the DR priority of the first PE device that is restored to normal and/or the IP address of the downstream interface of the first PE device that is restored to normal. The DR election message may be a Hello message, that is, the DR election message may be a PIM message with a Hello type. Please refer to FIG. 5, which shows a format of a packet header of a PIM message. As shown in FIG. 5, the packet header of the PIM packet may include: a version field, a type field, a reserved field, and a checksum field. The version field is used to indicate the version number of the PIM message, and the type field is used to indicate the packet type of the PIM message, where the PIM message is a PIMv2 version format. The PIM message is a Hello message; the reserved field is a reserved idle field; and the checksum field is used to indicate information used for verifying the PIM message.

For example, the Assert message in the embodiment of the present invention, such as the first Assert message, the second Assert message, the Assert message 1 and the Assert message 2, are PIM messages with the message type Assert.

S202. The second PE device receives the DR election message sent by the first PE device.

For example, the second PE device can receive the DR election message sent by the first PE device through its downstream interface. The DR election message can be received by the downstream interface of the second PE device in real time, because the DR election message does not belong to the multicast traffic.

S203. The second PE device performs DR election according to the DR election information of the first PE device that is restored to normal and the DR election information of the second PE device.

The DR election information of the second PE device includes a DR priority of the second PE device and/or an IP address of a downstream interface of the second PE device.

S204. The second PE device determines, according to the result of the DR election, that the first PE device that is restored to normal is upgraded to a DR.

The second PE device determines, according to the result of the DR election, that the first PE device that is restored to normal is upgraded to the DR, and may refer to the embodiment of the present invention to perform DR election for the first PE device and the second PE device. Related detailed description.

S205, the second PE device determines that the first PE device that is restored to normal is sent to the first PE device, and sends the Assert message 1 to the first PE device, where the Assert message 1 is used to recover from the normal The first PE device obtains information for conducting an Assert election.

In the embodiment of the present invention, the second PE device may obtain the Assert election information of the first PE device by sending an Assert message 1 to the first PE device. The Assert election information of the first PE device may include: a unicast routing protocol priority of the first PE device that is restored to normal and/or an IP address of a downstream interface of the first PE device that is restored to normal.

S206. The first PE device that is upgraded to the DR receives the Assert message 1 sent by the second PE device.

S207. The first PE device that is upgraded to the DR sends the Assert message 2 to the second PE device after receiving the Assert message 1. The Assert message 2 includes the first PE device. Assert election information.

In the embodiment, the Assert message 2 sent by the first PE device to the second PE device is used to indicate the second PE setting. Prepare for Assert elections. The Assert message 1 sent by the second PE device to the first PE device is used to obtain the Assert election information from the first PE device that is restored to be normal, that is, the first PE device is used to indicate that the recovery is normal. Feedback on its Assert election information.

The reserved field of the Assert message 1 is not an idle field. The reserved field of the Assert message 1 may indicate that the Assert message 1 is an extended Assert message. The extended Assert message is used to obtain information for performing Assert election from the first PE device that is restored to normal. Generally, the 7th to 15th bytes of the packet header of the PIM packet are reserved fields. In the embodiment of the present invention, at least one byte of the 7th to 15th bytes of the Assert packet 1 may be set. At least one bit of the Assert message 1 is extended. For example, the first bit in the 7th byte of the Assert message 1 may be set to 1 to indicate that the Assert message 1 is the extended Assert message.

S208. The second PE device receives the Assert message 2 sent by the first PE device.

S209. The second PE device performs an Assert election according to the Assert election information of the first PE device and the Assert election information of the second PE device, and deletes the second PE after the Assert election fails. Multicast forwarding entry saved by the device.

For example, the Assert election information of the second PE device may include: a unicast routing protocol priority of the second PE device and/or an IP address of a downstream interface of the second PE device.

The method for performing the Assert election by the second PE device according to the Assert election information of the first PE device and the Assert election information of the second PE device may include: comparing, by the second PE device, the second PE device The unicast routing protocol priority and the unicast routing protocol priority of the first PE device. If the unicast routing protocol priority of the second PE device is higher than the unicast routing protocol priority of the first PE device, the second PE device wins in the Assert election. If the unicast routing protocol priority of the second PE device is lower than the unicast routing protocol priority of the first PE device, the second PE device fails in the Assert election. If the unicast routing protocol priority of the second PE device is the same as the unicast routing protocol of the first PE device, the second PE device compares the IP address of the downstream interface of the second PE device. An IP address of a downstream interface with the first PE device. If the unicast routing protocol priority of the second PE device is the same as the unicast routing protocol of the first PE device, and the IP address of the downstream interface of the second PE device is greater than the first PE device The IP address of the downstream interface, the second PE device wins in the Assert election. If the unicast routing protocol priority of the second PE device is the same as the unicast routing protocol of the first PE device, and the IP address of the downstream interface of the second PE device is smaller than the first PE device The IP address of the downstream interface, the second PE device fails in the Assert election.

In the network scenario of the embodiment of the present invention, the unicast routing protocol priority of the first PE device is higher than the unicast routing protocol priority of the second PE device. The IP address of the downstream interface of the first PE device is greater than the IP address of the downstream interface of the second PE device. Therefore, if the second PE device performs an Assert election with the first PE device, the second PE device fails in the Assert election.

The method for controlling multicast transmission provided by the embodiment of the present invention, the first PE device returns to normal and is promoted to DR before the aging time Y of the period suppression mechanism arrives. The period suppression mechanism initiated by the second PE device in S102 also suppresses the receiving of the multicast traffic on the downstream interface of the second PE device, but does not receive the DR election report on the downstream interface of the second PE device. The text is suppressed. When the second PE device determines that the first PE device that is restored to the normal state is upgraded to the DR according to the DR election message, the second PE device immediately sends the Assert message 1 to the first PE device, and obtains the first PE device that is restored to the normal PE device. Assert election information. The second PE device does not need to wait for the detection period to be ended and determines that the multicast traffic is received in the detection period, and the Assert election is performed to prevent the second PE device and the first PE device from being multicast at the same time. The receiver forwards multicast traffic.

Optionally, based on the first application scenario of the embodiment of the present invention, the embodiment of the present invention further provides another implementation manner, as shown in FIG. 6. The scene shown in FIG. 6 is different from the scene shown in FIG. 4 in that S201-S204 included in FIG. 4 can be replaced with S301 of FIG. 6.

S301: The second PE device detects that the downstream interface of the second PE device is switched from the first state to the second state, and determines that the first PE device that is restored to normal is upgraded to the DR.

The first state is a state in which the downstream interface of the second PE device does not receive the multicast traffic, and the second state is a state in which the downstream interface of the second PE device receives the multicast traffic. The downstream interface of the second PE device is an interface capable of communicating with a multicast receiver.

It is conceivable that after the first PE device that is restored to the normal state obtains the multicast forwarding entry, the multicast traffic may be sent through the downstream interface of the first PE device that is restored to normal. The interface is an interface that can communicate with the multicast receiver. If the first PE device that returns to normal sends multicast traffic through its downstream interface, the downstream interface of the second PE device can receive the multicast traffic forwarded by the Layer 2 switch, and the multicast forwarded by the Layer 2 switch The traffic is the multicast traffic sent by the Layer 2 switch to the first PE device that is restored to normal through its downstream interface.

When the first PE device is a BDR, the multicast traffic is not forwarded. Therefore, if the downstream interface of the second PE device does not receive the multicast traffic, the downstream interface of the first PE device does not send the multicast traffic, that is, the first PE device is a BDR. If the downstream interface of the second PE device can receive the multicast traffic, the multicast traffic is sent by the downstream interface of the first PE device that is restored to normal. If the downstream interface of the second PE device is switched from the first state to the second state, the second PE device may determine that the first PE device that is restored to normal is upgraded to the DR. In this manner, the second PE device may send the first Assert message to the first PE device to obtain the Assert from the first PE device that is restored to normal when the first PE device that is restored to the normal state is upgraded to the DR. Election information. After the second PE device is elected to the BDR by the Assert election, the second PE device immediately deletes the multicast forwarding entry saved in the second PE device, and the first PE device and the second device are avoided. The PE device forwards multicast traffic to multicast receivers at the same time.

A second application scenario of the embodiment of the present invention is shown in FIG. 7. The second application scenario shown in FIG. 7 may be after S101-S104 included in FIG. 4, and further includes S401-S404:

S401: After the first PE device returns to normal, perform DR election with the second PE device, and determine that the first PE device is upgraded to the DR.

The method for performing the DR election on the first PE device and the second PE device, and determining the method for the first PE device to be upgraded to the DR may refer to the related method for performing the DR election, which is not described herein again. .

S402, the first PE device that is restored to the DR and the DR is sent to the second PE device to send the Assert message 3, and the Assert message 3 is used to indicate the second The PE device performs the Assert election.

For example, the Assert message 3 may include Assert election information of the first PE device. The Assert election information of the first PE device may include: a unicast routing protocol priority of the first PE device that is restored to normal, and/or an IP address of a downstream interface of the first PE device that is restored to the normal state.

S403. The second PE device receives the Assert message 3 sent by the first PE device.

S404. The second PE device performs an Assert election according to the Assert election information of the second PE device and the Assert election information of the first PE device included in the Assert message 3, and fails in the Assert election. Then, the multicast forwarding entry saved by the second PE device is deleted.

The second PE device according to the Assert election information of the second PE device and the Assert message 3 For the Assert election information of the first PE device, the specific method for performing the Assert election may refer to the related description of the Assert election of the second PE device in the first application scenario of the embodiment of the present invention, where the embodiment of the present invention is No longer.

The method for controlling multicast transmission provided by the embodiment of the present invention, the first PE device may also actively trigger the second PE device after being restored to the DR and obtained the multicast forwarding entry. Conduct an Assert election. The Assert election is not performed after the second PE device waits for the detection period to be received, and the second PE device and the first PE device are simultaneously multicast. The receiver forwards multicast traffic.

In the multiple implementation manners of the first scenario and the multiple implementation manners of the second scenario, the first PE device is before the aging time of the periodic suppression mechanism of the second PE device arrives. Return to normal and upgrade to DR. The downstream interface of the second PE device can detect the received multicast traffic in real time if the first PE device is restored to the DR after the aging time of the period suppression mechanism of the second PE device is restored. And conduct Assert elections. In this manner, the second PE device can delete the forwarding entry immediately after the Assert election fails, and prevent the second PE device and the first PE device from forwarding multicast traffic for the multicast receiver at the same time.

A third application scenario of the embodiment of the present invention may be as shown in FIG. 8. The scenario shown in FIG. 8 is after S101-S104 included in FIG. 4, and further includes S501-S503.

S501. After obtaining the multicast forwarding item, the first PE device that is restored to the DR and sends the multicast traffic through the downstream interface at the first time.

The first time is a time after the preset time of the first PE device that is faulty is restored to a normal time, and the preset time length is greater than or equal to the aging time of the cycle suppression mechanism. The downstream interface of the first PE device is an interface capable of communicating with a multicast receiver.

S502. The downstream interface of the second PE device receives the multicast traffic sent by the Layer 2 switch, where the multicast traffic is sent by the first PE device to the Layer 2 switch through its downstream interface.

S503. The second PE device performs an Assert election when the downlink interface receives the multicast traffic, and deletes the multicast forwarding entry saved by the second PE device after the Assert election fails.

For example, the method for performing the Assert election on the second PE device may be that the second PE device in the foregoing embodiment sends an Assert election message for obtaining the Assert election information to the first PE device.

The method for controlling multicast transmission provided by the embodiment of the present invention, the period suppression mechanism of the second PE device has expired at the first moment. If the downstream interface of the first PE device sends multicast traffic at the first moment, that is, after the periodic suppression mechanism of the second PE device fails, the second PE device may send the multicast traffic. Real-time perceived multicast traffic to its downstream interface. The second PE device may initiate an Assert election after the multicast traffic of the downstream interface is detected, and immediately delete the multicast forwarding entry saved in the second PE device, thereby avoiding the second PE device and the device. The first PE device forwards multicast traffic for the multicast receiver at the same time.

The embodiment of the present invention further provides a method for controlling multicast transmission. In the method for controlling multicast transmission, the first multicast forwarding entry may be pre-stored in the second PE device as the BDR. The first multicast forwarding entry includes a flag bit, and the flag bit is used to indicate that the first multicast forwarding entry cannot be used to forward the multicast traffic received by the upstream interface of the second PE device. The first multicast forwarding entry is not deleted after the second PE device is reduced from the DR to the BDR.

For example, after the second PE device is upgraded to the DR, the second multicast forwarding entry can be obtained, where the second multicast forwarding entry is used to forward the group received by the upstream interface of the second PE device. Broadcast traffic. The second multicast transfer The advertised item is absent from the first multicast forwarding entry, and the second multicast forwarding entry is the same as the other content of the first multicast forwarding entry. The second multicast forwarding entry is deleted after the second PE device performs the Assert election and the election fails.

The method for controlling the multicast transmission provided by the embodiment of the present invention, the predetermined tag bit in the first multicast forwarding entry indicates that the first multicast forwarding entry cannot be used to forward the first PE device. The multicast traffic received by the upstream interface cannot be forwarded according to the first multicast forwarding entry even if the multicast traffic received by the upstream interface of the second PE device is the BDR. In this way, the first PE forwarding entry is pre-stored in the second PE device, and the second PE device that is the BDR and the first PE device that serves as the DR forward the multicast traffic for the multicast receiver. Further, since the first multicast forwarding entry is pre-stored in the second PE device that is the BDR, the second PE device does not enable the cycle suppression when the downstream interface receives the multicast traffic. Mechanical.

In the method provided by the embodiment of the present invention, after the aging time of the period suppression mechanism or the period suppression mechanism is reached, the second PE device that is the BDR can detect the multicast traffic received by the downstream interface in real time, and initiates Assert elected. The second PE device that is the BDR can delete the multicast forwarding entry saved in the second PE device immediately after the Assert election fails, so as to avoid the second PE device that is the BDR and the DR device. A PE device forwards multicast traffic to multicast receivers at the same time.

The solution provided by the embodiment of the present invention is introduced from the perspective of the interaction between the first PE device and the second PE device. It can be understood that, in order to implement the above functions, the first PE device and the second PE device include corresponding hardware structures and/or software modules for performing the respective functions. Those skilled in the art will readily appreciate that the present invention can be implemented in a combination of hardware or hardware and computer software in conjunction with the PE devices and algorithm steps of the various examples described in the embodiments disclosed herein. Whether a function is implemented in hardware or computer software to drive hardware depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods for implementing the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present invention.

The embodiment of the present invention may divide the function module or the function unit of the first PE device and the second PE device according to the foregoing method example. For example, each function module or function unit may be divided according to each function, or two or two may be used. The above functions are integrated in one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules or functional units. The division of a module or a unit in the embodiment of the present invention is schematic, and is only a logical function division. In actual implementation, there may be another division manner.

FIG. 9 shows a possible structural diagram of the second PE device involved in the above embodiment. The second PE device as the BDR is upgraded to the DR after the failure of the first PE device as the DR, and the second PE device 900 includes a determining unit 901 and a sending unit 902.

The determining unit 901 is configured to determine that the first PE device that is restored to normal is upgraded to a DR after the first PE device returns to normal. For example, the determining unit 901 is configured to support S202, S203, S204 in FIG. 4, S301 in FIG. 6, and/or other processes for the techniques described herein.

The sending unit 902 is configured to: when the determining unit 901 determines that the first PE device that is restored to normal is upgraded to the DR, send the first Assert message to the first PE device that is restored to normal, the first Assert The message is used to obtain information about the Assert election from the first PE device that is restored to normal. The sending unit 902 interacts with the first PE device that returns to normal, and obtains information for performing Assert election from the first PE device that is restored to normal. For example, the transmitting unit 902 is configured to support S205 in FIG. 4 and/or other processes for the techniques described herein.

Corresponding to the implementation manner shown in FIG. 4, as shown in FIG. 10, the determining unit 901 may include: a receiving subunit 9011, a DR electing subunit 9012, and a determining subunit 9013. The receiving subunit 9011 is used to support the map. S202 in 4, the DR election sub-unit 9012 is used to support S203 in FIG. 4, and the determining sub-unit 9013 is used to support S204 in FIG.

Further, as shown in FIG. 11, the second PE device 900 may further include: a receiving unit 903, an assertion election unit 904, and an entry deletion unit 905. The receiving unit 903 is configured to receive the multicast traffic, the Assert packet, and/or the DR election packet sent by the first PE device. For example, the receiving unit 903 is configured to support S208 in FIG. 4 or FIG. 6, S403 in FIG. 7, S502 in FIG. 8, and/or other processes for the techniques described herein. The assertion election unit 904 is configured to perform an Assert election according to the Assert message sent by the first PE device. For example, the assertion election unit 904 is configured to support the Assert election function in S209 in FIGS. 4 and 6, the Assert election function in S404 in FIG. 7, the Assert election function in S503 in FIG. 8, and/or used in the description herein. Other processes of technology. The entry deletion unit 905 is configured to delete the multicast forwarding entry saved in the second PE device 900 after the Assert election fails. For example, the entry deletion unit 905 can be used to support the following in FIG. 4 and FIG. The multicast forwarding entry function in S209, the multicast forwarding entry function in S404 in FIG. 7, the multicast forwarding entry function in S503 in FIG. 8, and/or other processes for the techniques described herein. The second PE device 900 may further include a storage unit for storing program codes and data of the second PE device 900.

In the case of employing an integrated unit, the determining unit 901, the assertion electing unit 904, and the entry deleting unit 905 may be implemented in one processing unit, which may be a processor or a controller, for example Can be CPU, general purpose processor, digital signal processor (English: Digital Signal Processor, referred to as: DSP), ASIC (English: Application-Specific Integrated Circuit, referred to as: ASIC), field programmable gate array (English: Field Programmable Gate Array (abbreviation: FPGA) or other programmable logic device, transistor logic device, hardware component, or any combination thereof. It is possible to implement or carry out the various illustrative logical blocks, modules and circuits described in connection with the present disclosure. The processing unit may also be a combination of computing functions, such as one or more microprocessor combinations, a combination of a DSP and a microprocessor, and the like. The sending unit 901 and the receiving unit 903 can be implemented by being integrated in one communication unit, and the communication unit can be a communication interface, a transceiver circuit or a transceiver, and the like. The storage unit can be a memory.

When the processing unit is a processor, the communication unit is a communication interface, and the storage unit is a memory, the second PE device in the embodiment of the present invention may be the second PE device 1200 shown in FIG.

Referring to FIG. 12, the second PE device 1200 includes a processor 1201, a communication interface 1202, a memory 1203, and a bus 1204. The processor 1201, the communication interface 1202, and the memory 1203 are connected to each other through a bus 1204. The bus 1204 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus 1204 can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in Figure 12, but it does not mean that there is only one bus or one type of bus.

The embodiment of the present invention further provides a non-volatile storage medium, where the one or more program codes are stored, when the processor 1201 of the second PE device 1200 executes the program code, The second PE device 1200 performs the related method steps in any one of FIG. 4, FIG. 6, FIG. 7, or FIG. 8, and interacts with the first PE device to implement control of multicast transmission.

The detailed description of each functional unit or functional module in the second PE device provided by the embodiment of the present invention, and each functional unit or functional module perform the steps in any of FIG. 4, FIG. 6, FIG. 7, or FIG. For the technical effects of the related method steps, refer to the related description in the method embodiment of the present invention, and details are not described herein again.

FIG. 13 is a schematic diagram showing a possible structure of the first PE device involved in the above embodiment. The second PE device as the BDR is upgraded to the DR after the failure of the first PE device as the DR, and the first PE device 1300 includes a determining unit 1301 and a transmitting unit 1302. The determining unit 1301 is configured to determine that the first PE device is upgraded to the DR after the faulty first PE device returns to normal, for example, the determining unit 1301 is configured to support S401 and/ in FIG. 7 Or other processes for the techniques described herein. The sending unit 1302 is configured to, when the determining unit 1301 determines that the first PE device that is restored to be normal is upgraded to a DR, interact with the second PE device, and instruct the second PE device to perform an Assert election. For example, the transmitting unit 1302 is configured to support S104, S201, and S207 in FIG. 4, S104, S207 in FIG. 6, S104, S402 in FIG. 7, S104, S502 in FIG. 8, and/or used in this document. Other processes of the described technology.

Further, the first PE device 1303 may further include: a receiving unit and a DR election unit. The receiving unit is configured to receive the multicast traffic, the Assert packet, and the DR election message sent by the second PE device, for example, the receiving unit is configured to support S206 in FIG. 4 or FIG. 6 and/or used in the description herein. Other processes of technology. The DR election unit is configured to perform DR election according to the DR election message sent by the first PE device. For example, the DR election unit is used to support S101 and/or in FIG. 4, FIG. 6, FIG. 7, or FIG. Other processes of the techniques described herein. Of course, the first PE device 1300 may further include: an entry deletion unit, configured to delete the multicast forwarding entry saved in the first PE device 1300 after the first PE device 1300 is faulty, for example, deleting the entry The unit may be used to support S103 in Figures 4, 6, 7, or 8 and/or other processes for the techniques described herein. The first PE device 1300 may further include a storage unit for storing program codes and data of the first PE device 1300.

In the case of adopting an integrated unit, functional units such as the determining unit 1301, the DR electing unit, and the entry deleting unit may be implemented in one processing unit, and the processing unit may be a processor or a controller. For example, it can be a CPU, a general purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. It is possible to implement or carry out the various illustrative logical blocks, modules and circuits described in connection with the present disclosure. The processing unit may also be a combination of computing functions, such as one or more microprocessor combinations, a combination of a DSP and a microprocessor, and the like. The transmitting unit 1302 and the receiving unit may be implemented by being integrated in one communication unit, and the communication unit may be a communication interface, a transceiver circuit or a transceiver, or the like. The storage unit can be a memory.

When the processing unit is a processor, the communication unit is a communication interface, and the storage unit is a memory, the first PE device involved in the embodiment of the present invention may be the first PE device 1400 shown in FIG. 14 .

Referring to FIG. 14, the first PE device 1400 includes a processor 1401, a communication interface 1402, a memory 1403, and a bus 1404. The processor 1401, the communication interface 1402, and the memory 1403 are connected to each other through a bus 1404. The bus 1404 can be a PCI bus or an EISA bus. The bus 1404 can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in Figure 14, but it does not mean that there is only one bus or one type of bus.

The embodiment of the present invention further provides a non-volatile storage medium, where the one or more program codes are stored, when the processor 1401 of the first PE device 1400 executes the program code, The first PE device 1400 performs the related method steps in any one of FIG. 4, FIG. 6, FIG. 7, or FIG. 8, and interacts with the second PE device to implement control of multicast transmission.

The detailed description of each functional unit or function module in the first PE device provided by the embodiment of the present invention, and each functional unit or function module perform related methods in any one of FIG. 4, FIG. 6, FIG. 7, or FIG. For the technical effects of the steps, reference may be made to the related description in the method embodiment of the present invention, and details are not described herein again.

The embodiment of the present invention further provides a second PE device. The second PE device that is the BDR is upgraded to a DR after the first PE device that is the DR is faulty. The second PE device includes: an acquiring unit and a storage unit. The obtaining unit is configured to obtain a first multicast forwarding entry. The storage unit is configured to save the first multicast forwarding entry obtained by the acquiring unit. The first multicast forwarding entry includes a flag bit, and the flag bit is used to indicate that the first multicast forwarding entry cannot be used to forward the multicast traffic received by the upstream interface of the second PE device. The first multicast forwarding entry is not deleted after the second PE device is reduced from the DR to the BDR.

Of course, the second PE device may further include: a receiving unit, a sending unit, a DR election unit, and an entry deletion unit. For a specific function of the function unit, such as the receiving unit, the sending unit, the DR election unit, and the entry deletion unit, refer to the detailed description of the corresponding functional unit in the foregoing embodiment, and details are not described herein again.

In the case of adopting an integrated unit, functional units such as the acquisition unit, the DR election unit, and the entry deletion unit may be integrated into one processing unit, and the processing unit may be a processor or a controller, for example, It can be a CPU, a general purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. It is possible to implement or carry out the various illustrative logical blocks, modules and circuits described in connection with the present disclosure. The processing unit may also be a combination of computing functions, such as one or more microprocessor combinations, a combination of a DSP and a microprocessor, and the like. The receiving unit and the sending unit may be implemented by being integrated in one communication unit, and the communication unit may be a communication interface, a transceiver circuit or a transceiver, or the like. The storage unit can be a memory.

When the processing unit is a processor, the communication unit is a communication interface, and the storage unit is a memory, the second PE device according to the embodiment of the present invention may include: a processor, a communication interface, a memory, and a bus. The processor, the communication interface, and the memory are connected to each other through a bus. The bus may be a PCI bus or an EISA bus. The bus can be divided into an address bus, a data bus, a control bus, and the like.

The embodiment of the present invention further provides a non-volatile storage medium, where the non-volatile storage medium stores a first multicast forwarding entry and one or more program codes, when the processor of the second PE device executes the In the program code, when the communication interface of the second PE device receives the multicast traffic through the downstream interface, the second PE device does not enable the cycle suppression mechanism.

For detailed descriptions and technical effects of the various functional units or functional modules in the second PE device provided by the embodiments of the present invention, reference may be made to the related description in the method embodiments of the present disclosure, and details are not described herein again.

The steps of a method or algorithm described in connection with the present disclosure may be implemented in a hardware, or may be implemented by a processor executing software instructions. The software instructions can be composed of corresponding software modules, which can be stored in random access memory (English: Random Access Memory, RAM for short), flash memory, read only memory (English: Read Only Memory, ROM), erasable Programmable read-only memory (English: Erasable Programmable ROM, EPROM for short), electrically erasable programmable read-only memory (English: Electrically EPROM, EEPROM for short), register, hard disk, mobile hard disk, CD-ROM (CD-ROM) Or any other form of storage medium known in the art. An example storage medium is coupled to a processor such that the processor can read information from, and can write information to, the storage medium. Of course, the storage medium can also be an integral part of the processor. The processor and the storage medium can be located in an ASIC. Additionally, the ASIC can be located in a core network interface device. Of course, the processor and the storage medium may also exist as discrete components in the core network interface device.

Those skilled in the art will appreciate that in one or more examples described above, the functions described herein can be implemented in hardware, software, firmware, or any combination thereof. These functions can be saved when implemented in software. It is stored in a computer readable medium or transmitted as one or more instructions or code on a computer readable medium. Computer readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one location to another. A storage medium may be any available media that can be accessed by a general purpose or special purpose computer.

The specific embodiments of the present invention have been described in detail with reference to the preferred embodiments of the present invention. The scope of the protection, any modifications, equivalent substitutions, improvements, etc., which are made on the basis of the technical solutions of the present invention, are included in the scope of the present invention.

Claims

A method for controlling multicast transmission, the second carrier edge PE device serving as the backup designated router BDR is promoted to the DR after the first PE device as the designated router DR is faulty, wherein the method includes :

After the first PE device returns to normal, the second PE device determines that the first PE device that is restored to normal is upgraded to the DR;

When the second PE device determines that the first PE device that is restored to normal is upgraded to the DR, sends a first asserted Assert message to the first PE device, where the first Assert message is used to The first PE device that has returned to normal obtains information about the Assert election.
The method of claim 1, wherein the determining, by the second PE device, that the first PE device is restored to the DR after the first PE device is restored to the DR comprises:

The second PE device receives the DR election message sent by the first PE device that is restored to the normal state, and the DR election message carries the DR election information of the first PE device that is restored to the normal state, and the recovery is normal. The DR election information of the first PE device includes the DR priority of the first PE device that is restored normally and/or the Internet Protocol IP address of the downstream interface of the first PE device that is restored to the normal state;

The second PE device performs DR election according to the DR election information of the first PE device that is restored to normal and the DR election information of the second PE device, where the DR election information of the second PE device includes the foregoing The DR priority of the second PE device and/or the IP address of the downstream interface of the second PE device;

The second PE device determines, according to the result of the DR election, that the first PE device that is restored to normal is upgraded to the DR.
The method of claim 1, wherein the determining, by the second PE device, that the first PE device is restored to the DR after the first PE device is restored to the DR comprises:

The second PE device detects that the downstream interface of the second PE device is changed from the first state to the second state, and determines that the first PE device that is restored to normal is upgraded to the DR, where the first state is The downstream interface of the second PE device does not receive the state of the multicast traffic, and the second state is the state in which the downstream interface of the second PE device receives the multicast traffic, and the downstream of the second PE device The interface is an interface that can communicate with the multicast receiver.
The method according to claim 3, wherein the multicast traffic is the multicast traffic sent by the first PE device that is restored to normal through the downstream interface of the first PE device that is restored to the normal state at the first moment. The first time is the time after the time when the first PE device that is faulty is restored to the normal time, and the preset time length is greater than or equal to the aging time of the cycle suppression mechanism, and the first PE that returns to normal The downstream interface of the device is an interface that can communicate with the multicast receiver.
The method according to any one of claims 1 to 4, wherein the method further comprises:

The second PE device receives the second Assert message sent by the first PE device that is restored to the normal state, and the second Assert message includes the Assert election information of the first PE device.

The second PE device performs an Assert election according to the Assert election information of the first PE device and the Assert election information of the second PE device;

After the Assert election fails, the second PE device deletes the multicast forwarding entry saved by the second PE device.
A method for controlling multicast transmission, the second carrier edge PE device serving as the backup designated router BDR is promoted to the DR after the first PE device device that is the designated router DR is faulty, wherein the party is The law includes:

After the faulty first PE device returns to normal, it is determined to be promoted to the DR;

After the first PE device that obtains the normality obtains the multicast forwarding entry, the first Assert packet is sent to the second PE device to perform the Assert message. election.
The method according to claim 6, wherein after the failed first PE device returns to the DR, the first PE device that returns to normal sends the first PE device to the second PE device. Before an Assert message, the method further includes:

The first PE device that returns to normal sends a DR election message to the second PE device, where the DR election message includes DR election information of the first PE device, and DR election information of the first PE device. The DR priority of the first PE device and/or the Internet Protocol IP address of the downstream interface of the first PE device are included.
The method according to claim 6 or 7, wherein after the first PE device that returns to the normality obtains the multicast forwarding entry, the method further includes:

The first PE device that restores normality sends the multicast traffic to the downstream interface of the first PE device that is restored to normal. The downstream interface of the first PE device that is restored to normal is an interface that can communicate with the multicast receiver.
A second carrier edge PE device, the second PE device that serves as the backup designated router BDR is upgraded to the DR after the first PE device that is the designated router DR is faulty, and the second PE device includes:

a determining unit, configured to: after the first PE device returns to normal, determine that the first PE device that is restored to normal is upgraded to the DR;

a sending unit, configured to send a first assertion Assert message to the first PE device, where the determining unit determines that the first PE device that is restored to be normal is upgraded to the DR, where the first Assert message is used by the determining unit Information for performing an Assert election is obtained from the first PE device that is restored to normal.
The second PE device according to claim 9, wherein the determining unit comprises:

a receiving sub-unit, configured to receive the DR election message sent by the first PE device that is restored to the normal state, where the DR election message carries the DR election information of the first PE device that is restored to normal, and the recovery is normal. The DR election information of the first PE device includes the DR priority of the first PE device that is restored normally and/or the Internet Protocol IP address of the downstream interface of the first PE device that is restored to the normal state;

a DR election sub-unit, configured to perform DR election according to the DR election information of the first PE device and the DR election information of the second PE device that are received by the receiving sub-unit, where the second PE device is The DR election information includes the DR priority of the second PE device and/or the IP address of the downstream interface of the second PE device;

Determining a sub-unit, configured to determine, according to the result of the DR election obtained by the DR election by the DR election sub-unit, that the first PE device that returns to normal is upgraded to the DR.
The second PE device according to claim 9, wherein the determining unit is specifically configured to:

Detecting that the downstream interface of the second PE device is switched from the first state to the second state, determining that the first PE device that is restored to normal is upgraded to the DR, and the first state is that the second PE device is The downstream interface does not receive the state of the multicast traffic, the second state is the state in which the downstream interface of the second PE device receives the multicast traffic, and the downstream interface of the second PE device is capable of multicasting The interface that the receiver communicates with.
The second PE device according to claim 11, wherein the multicast traffic is sent by the first PE device that is restored to normal at the first time via the downstream interface of the first PE device that is restored to the normal state. The multicast time, the first time is the time after the time when the faulty first PE device returns to normal, and the preset time length is greater than or equal to the aging time of the period suppression mechanism, and the normal time is restored. The downstream interface of the first PE device is capable of An interface that is sufficient to communicate with multicast receivers.
The second PE device according to any one of claims 9 to 12, wherein the method further comprises:

a receiving unit, configured to receive the second Assert message sent by the first PE device that is restored to be normal, where the second Assert message includes Assert election information of the first PE device;

Determining an election unit, configured to perform an Assert election according to the Assert election information of the first PE device and the Assert election information of the second PE device received by the receiving unit;

The entry deletion unit is configured to delete the multicast forwarding entry saved by the second PE device after the Assert election of the election election unit fails.
A first carrier edge PE device, the second PE device that serves as the backup designated router BDR is upgraded to the DR after the first PE device that is the designated router DR is faulty, and the first PE device includes:

a determining unit, configured to determine that the first PE device is upgraded to the DR after the faulty first PE device returns to normal;

a sending unit, configured to send a first assertion Assert message to the second PE device after the determining unit determines that the first PE device is upgraded to the DR and obtains a multicast forwarding entry, where the first The Assert message is used to instruct the second PE device to perform an Assert election.
The first PE device according to claim 14, wherein the sending unit is further configured to: after the determining unit determines that the first PE device is upgraded to the DR, the sending unit is configured to Before the second PE device sends the first Assert packet,

Sending a DR election message to the second PE device, where the DR election message includes the DR election information of the first PE device, and the DR election information of the first PE device includes the DR of the first PE device. Priority and/or internet protocol IP address of the downstream interface of the first PE device.
The first PE device according to claim 14 or 15, wherein the sending unit is further configured to: after the obtaining, by the first PE device that is restored, obtain a multicast forwarding entry, The downstream interface of the first PE device sends the multicast traffic, and the downstream interface of the first PE device that is restored to normal is an interface that can communicate with the multicast receiver.