CN109039921B

CN109039921B - Designated router switching method, multicast router and multicast network

Info

Publication number: CN109039921B
Application number: CN201810968480.9A
Authority: CN
Inventors: 周儒强
Original assignee: Maipu Communication Technology Co Ltd
Current assignee: Maipu Communication Technology Co Ltd
Priority date: 2018-08-23
Filing date: 2018-08-23
Publication date: 2021-08-03
Anticipated expiration: 2038-08-23
Also published as: CN109039921A

Abstract

The embodiment of the application discloses a designated router switching method, a multicast router and a multicast network, relates to the field of communication, and can rapidly reselect DR and complete switching under the condition that DR of a designated router in the multicast network fails, so that the influence of DR failure on data stream transmission is reduced. The method comprises the following steps: the method comprises the steps that when DR is detected to be invalid, the DR sends an ISIS notification message for requesting DR switching to a backup router, and when DR recovery is detected, the DR sends an ISIS notification message for requesting DR back switching to the backup router; the backup router receives the ISIS notification message, determines a network segment for DR switching or DR back switching according to the ISIS notification message, and acquires a first interface corresponding to the network segment of the backup router; when the DR requests DR switching, the backup router adjusts the priority of the first interface to be the highest; when the DR requests a DR failover, the backup router adjusts the priority of the first interface to the lowest. The embodiment of the application is used for rapidly reselecting DR and completing switching when DR fails.

Description

Designated router switching method, multicast router and multicast network

Technical Field

The present application relates to the field of communications, and in particular, to a method for switching a designated router, a multicast router, and a multicast network.

Background

In a multicast network, a server usually sends a unidirectional data stream to a plurality of user equipments in a one-to-many manner, and when a plurality of multicast routers exist in the multicast network, the plurality of multicast routers elect each Router in order by comparing priorities of the routers according to the specification of an Internet Group Management Protocol (IGMP), and the Router with the highest priority is elected as a Designated Router (DR) and forwards the multicast data stream to the user equipments through the DR. When a certain interface of the DR fails or a link between the DR and the user equipment fails, due to the limitation of an IGMP protocol between the user equipment and the DR, the DR can be confirmed to be invalid after a timing period of a timer, and then, other multicast routers determine a new DR again in an election mode. This process generally lasts for 5-10 seconds, and in this process, the data stream transmitted by the server during this time period is lost because the DR cannot normally forward the data stream to the user equipment.

At present, the application range of the multicast network is very wide, for example, services such as network live broadcast, network games, video conferences and the like all depend on the multicast network for data bearing, and this current situation also has a higher requirement on the stability of the multicast router for forwarding data streams. When a certain DR fails and a new DR is determined again, the data stream loss generated in the process can affect the experience of the user and increase the pressure of maintenance personnel.

In view of the above drawbacks, a solution generally adopted is to use a high-performance DR device, or to reduce the probability of DR failure in a link bundling manner (e.g., simultaneous transmission of multiple network cables). The adoption of high-performance DR equipment increases the cost, and when DR fails, the condition that the transmitted data stream is interrupted for a long time still occurs in the two modes, and the problem that the data stream is lost due to DR failure is not solved essentially.

Disclosure of Invention

The embodiment of the application provides a designated router switching method, a multicast router and a multicast network, which can rapidly reselect DR and complete switching under the condition that DR in the multicast network fails, and reduce the influence of DR failure on data stream transmission.

In a first aspect, a method for switching designated routers is provided, which is applied to a multicast network including a DR and a backup router, and includes: the method comprises the steps that when DR detects DR failure, the DR sends an Intermediate System-to-Intermediate System (ISIS for short) notification message for requesting DR switching to a backup router, and when DR recovery is detected, the DR sends an ISIS notification message for requesting DR back switching to the backup router; the backup router receives the ISIS notification message, determines a network segment for DR switching or DR back switching according to the ISIS notification message, and acquires a first interface corresponding to the network segment of the backup router; when the DR requests DR switching, the backup router adjusts the priority of the first interface to be the highest; when the DR requests DR to switch back, the backup router adjusts the priority of the first interface to be the lowest, so that a new round of DR election can be directly carried out without waiting for a timing period. For example, when a DR switching request is made, because the priority of the adjusted backup router is the highest, the backup router with the highest election priority is the router after switching, when a DR switchback request is made, because the DR listed in the previous round before the DR is necessarily higher than the priority of the adjusted backup router, and finally the DR is elected as the DR of the current round, a new round of election can be directly performed without waiting for the timer timing period to arrive, the time for entering the DR election is shortened, so that the DR switching can be quickly completed, the influence of the DR switching on data stream transmission when the DR fails is reduced, and after the DR is recovered from the failure, the DR can be quickly switched back, and the data loss is reduced.

In one possible design, the ISIS advertisement message includes a message type, an Internet Protocol (IP) address of the second interface, and a netmask of the second interface; the message type indicates that the DR requests DR switching or DR back switching; the second interface is an interface for DR to switch or back-switch, so that an independent ISIS protocol is operated between every two routers for transmitting ISIS notification messages, and when DR fails or recovers, the backup router can determine the state of DR and the related information of the second interface in DR according to the related information in the ISIS notification messages sent by DR.

In one possible design, the ISIS advertisement message includes a type-Length-Value (TLV) field, where the TLV field carries a message type, an IP address of the second interface, and a network mask, and such a special TLV is designed to notify the state of the DR and information related to the second interface in the DR to other routers at a programmatically small change cost, so as to shorten the switching time of the DR to a millisecond level.

In a second aspect, a router is provided, where the multicast router is a backup router of a DR, and includes: a receiving unit, configured to receive an ISIS notification message sent by a DR, where the ISIS notification message indicates that the DR requests DR handover or DR cutback; a determining unit, configured to determine, according to the ISIS advertisement message, a network segment where the DR performs DR handover or DR back handover; the acquisition unit is used for acquiring a first interface corresponding to the router and the network segment; the adjustment unit is used for adjusting the priority of the first interface to be the highest when the DR requests DR switching; when the DR requests DR to switch back, the priority of the first interface is adjusted to the lowest.

In one possible design, the ISIS advertisement message includes a message type, an IP address of the second interface, and a netmask of the second interface; the message type indicates that the DR requests DR switching or DR back switching; the second interface is an interface for DR to perform DR switching or DR switchback.

In one possible design, the ISIS advertisement message includes a TLV field that carries the message type, the IP address of the second interface, and a network mask.

In a third aspect, a router is provided, where the multicast router, as a DR, includes: the detection unit is used for notifying the notification unit when DR failure or DR recovery is detected; the notification unit is used for sending an ISIS notification message for requesting DR switching to the backup router when the DR failure is detected by the detection unit; and for sending an ISIS advertisement message for requesting a DR cutback to the backup router when the DR restoration is detected by the detection unit.

In a fourth aspect, a multicast network is provided, the multicast network comprising the backup router provided in the second aspect and the DR provided in the third aspect.

The embodiment of the application provides a designated router switching method, a multicast router and a multicast network, wherein when DR is detected to be invalid, DR sends an ISIS notification message for requesting DR switching to a backup router, and when DR recovery is detected, the DR sends an ISIS notification message for requesting DR back switching to the backup router; the backup router receives the ISIS notification message, determines a network segment for DR switching or DR back switching according to the ISIS notification message, and acquires a first interface corresponding to the network segment of the backup router; when the DR requests DR switching, the backup router adjusts the priority of the first interface to be the highest; when the DR requests a DR failover, the backup router adjusts the priority of the first interface to the lowest. Therefore, a new round of election can be directly carried out without waiting for the timing period of the timer to arrive, the time for entering DR election is shortened, DR switching can be rapidly completed, the influence of DR switching on data stream transmission is reduced when DR fails, and back switching can be rapidly carried out after the failed DR is recovered, so that data loss is reduced.

Drawings

Fig. 1 is a schematic diagram of a network topology provided in an embodiment of the present application;

fig. 2 is a schematic diagram of a hardware structure of a multicast router according to an embodiment of the present application;

fig. 3 is a schematic flowchart of a method for switching a designated router according to an embodiment of the present application;

fig. 4 is a schematic structural diagram of a backup router according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of a backup router according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of a backup router according to an embodiment of the present application;

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

fig. 8 is a schematic structural diagram of a DR provided in an embodiment of the present application;

fig. 9 is a schematic structural diagram of a DR provided in an embodiment of the present application.

Detailed Description

For ease of understanding, some of the concepts related to the present application are illustratively presented for reference. As follows:

and (3) ISIS: the Intermediate System-to-Intermediate System (chinese name: Intermediate System to Intermediate System) is a dynamic routing Protocol designed by ISO (International Organization for Standardization) for CLNP (Connection Less Network Protocol).

IGMP: internet Group Management Protocol (chinese name: Internet Group Management Protocol) is a multicast Protocol in the Internet Protocol family, which runs between the user equipment and the multicast router and is used to manage the transmission of multicast messages between the user equipment and the multicast router.

DR: a Designated Router (chinese name: Designated Router), which is called Designated Router, and when there are multiple multicast routers in a local area network, only one multicast Router will forward the multicast packet to the user.

Backup router: the router can be used as a backup router of the designated router in the multicast network, and when the designated router fails, the router takes over the operation of the designated router.

TLV: the Tag Length Value is a message format widely applied to the communication field, and can form required specific message content by defining different meanings of three elements.

The method and the device can be applied to the scene that a plurality of multicast routers exist in the multicast network, and when DR fails, DR is elected again quickly and switching is completed.

The network topology architecture applied in the present application may include a Multicast source, at least two Multicast routers and a plurality of user equipments, an Independent Multicast Protocol (PIM for short) may be operated between the Multicast source and the at least two Multicast routers, the at least two Multicast routers and the plurality of user equipments belong to a same user lan, and may communicate in the user lan through the IGMP. The precondition for realizing the scheme of the application is that an independent intermediate system to intermediate system ISIS protocol is operated between every two multicast routers, and then a same ISIS link database exists between the two multicast routers. When DR fails, the DR sends an ISIS notification message to other multicast routers except the DR in at least two multicast routers to request switching to other multicast routers, and the other multicast routers determine first interfaces respectively corresponding to network segments switched by the DR according to relevant information carried in the ISIS notification message, modify the priority of the first interfaces, rapidly enter and reselect the DR and complete switching under the condition of not waiting for the timing period of a timer, and reduce the influence of DR failure on data stream transmission.

As shown in fig. 1, a network topology architecture diagram provided in this embodiment of the present application includes two multicast routers, routerA and routerB, where an independent ISIS protocol is operated between the two routers, and then the routerA and the routerB may have a same ISIS link database, and after the routerA is elected as DR, the routerB is a backup router of the routerA, and when the routerA (DR) fails, in the present application scheme, the routerA sends an ISIS advertisement message with a DR handover indication to the routerB (backup router), where the advertisement message is used to indicate DR handover, and after receiving the ISIS advertisement message, the routerB performs a corresponding DR handover operation. And after the routerA recovers, the routerA actively sends an ISIS notification message with a DR back-cut instruction to the routerB, and the routerB performs corresponding DR back-cut operation after receiving the ISIS notification message.

As shown in fig. 2, the hardware structure of the multicast router 20 includes a Central Processing Unit (CPU) 201, a switch chip 202, a backplane bus 203, and an interface 204. Specifically, the CPU201 is used as a processing module of the router, and is configured to process most protocol packets, such as an ISIS protocol packet in the embodiment of the present application, where the processing procedure may be operations of extracting information in the ISIS protocol packet, performing calculation, generating a response packet, and the like; the switch chip 202 is a forwarding module of the router, and is configured to process most non-protocol packets, such as directly forwarding data without CPU processing; the backplane bus 203 is used as an internal transmission channel of the router, and is used for transmitting information such as protocol messages to be processed to the CPU201 through a logic channel for processing; the interface 204 may be used to send or receive ISIS protocol messages, data, and the like.

On the basis of the network topology architecture, an embodiment of the present application provides a method for switching a designated router, as shown in fig. 3, including:

301. when DR detects DR failure, the DR sends ISIS notification message for requesting DR switching to the backup router; when a DR recovery is detected, an ISIS advertisement message requesting a DR cutback is sent to the backup router.

The DR is any one of the at least two multicast routers, the backup router is any one of the at least two multicast routers except the DR, the ISIS notification message comprises a message type, an IP address of a second interface and a network mask of the second interface, wherein the message type indicates that the DR requests DR switching or DR switchback, and the second interface is an interface for the DR to perform DR switching or DR switchback.

When the DR detects that the DR itself is invalid, the DR sends an ISIS notification message for DR switching to a backup router running the same ISIS protocol, so that the backup router performs DR switching according to the ISIS notification message for DR switching sent by the DR. When the DR detects the recovery of the DR, the DR sends an ISIS notification message for DR switchback to a backup router running the same ISIS protocol, so that the backup router performs DR switchback according to the ISIS notification message for DR switchback sent by the DR, namely, the DR is switched back to the DR again from a failure state.

In the embodiment of the present application, the DR failure may include a failure of a communication link between the DR and the user equipment in the user local area network, or a failure of a certain routing interface in the DR equipment. It is understood that, in the embodiment of the present application, all routing interfaces that do not include a DR fail, i.e., the case where a DR is down.

In a possible design, a special type-length-value TLV field designed in this application may be included in the ISIS advertisement message, and the message type, the IP address of the second interface, and the network mask of the second interface may be carried by the special TLV field. The special TLV field carries the message type, the IP address of the second interface and the network mask of the second interface, so that the switching time of DR can be shortened to a millisecond level with smaller change cost in a program, and a mechanism for performing DR election after a timing period in the prior art is replaced.

302. And the backup router receives the ISIS notification message, determines a network segment for DR switching or DR back switching according to the ISIS notification message, and acquires a first interface corresponding to the network segment of the backup router.

The backup router determines the network segment where DR performs DR handover or DR cutback according to the IP address, such as 10.0.1.0, of the second interface where DR requests DR handover or DR cutback carried in the ISIS advertisement message and the network mask, such as 24, of the second interface, where the method for determining the network segment according to the IP address and the network mask may be a method well known to those skilled in the art, and this is not described in detail in this application. And then, the backup router searches a first interface connected with the network segment locally according to the determined network segment.

303. When the DR requests DR switching, the backup router adjusts the priority of the first interface to be the highest; when the DR requests a DR failover, the backup router adjusts the priority of the first interface to the lowest.

And after receiving the ISIS notification message, the backup router determines that the DR requests DR switching or DR back switching according to the message type in the ISIS notification message.

Exemplarily, if the message type in the ISIS advertisement message is 1, the backup router determines that DR fails according to the message type value, and the DR requests DR switching; and if the message type in the ISIS notification message is 0, the backup router determines DR recovery according to the message type, and the DR requests DR back-switching.

When the backup router determines that the DR requests DR switching according to the message type in the ISIS advertisement message, the backup router adjusts the priority of the first interface of the backup router determined before to be the highest, for example, the priority of the first interface is set to be the maximum value, which may be 255; if the backup router determines that the DR requests DR to switch back according to the message type in the ISIS advertisement message, the priority of the first interface of the backup router is adjusted to be the lowest, for example, the lowest value may be 1, and the backup router participates in the selection of DR according to the adjusted priority of the first interface. Therefore, the DR is determined to be invalid after the timer reaches the timing period of the timer under the condition that the DR is invalid, and then a new round of DR election is started. According to the method and the device, the backup router can quickly acquire DR failure by transmitting the ISIS notification message, and can quickly perform DR election under the condition of adjusting the interface priority. In the same way, the DR quick back cut can be realized.

In the process of DR election, because IGMP protocol is operated between at least two multicast routers and a plurality of user equipment, DR election can be carried out according to the protocol. Specifically, the router with the highest priority is elected as DR according to the priority of the router interface, and under the condition of the same priority, the router with the highest IP address can be further elected according to the IP address of the router, and the router with the highest IP address is elected as DR. As is well known to those skilled in the art, the election rule is defined by the IGMP protocol and will not be described in further detail in this application.

The election process can adopt a common network outlet scene on the network topology, the influence on the current network is small, new network equipment does not need to be added in most scenes, only the software version corresponding to the router needs to be upgraded to support the special TLV, and the networking cost is reduced. Meanwhile, the election method reduces the time for re-electing DR and completing switching in principle, and can be effectively combined with the solution for reducing DR failure probability in the prior art, so that the influence of DR failure on data stream transmission is reduced to a relatively low level. In addition, when the failed DR is recovered, the back switching can be rapidly carried out in a short time, and the data loss is reduced.

According to the above description of the method process, the backup router may also have the method flow of DR, that is, when the backup router is used as DR, any one of the at least two multicast routers (including DR in the above method flow) except the backup router is used as the backup router to perform the above process.

The embodiment of the application provides a switching method of a designated router, when DR is detected to be invalid, the DR sends an ISIS notification message for requesting DR switching to a backup router, and when DR recovery is detected, the DR sends an ISIS notification message for requesting DR back switching to the backup router; the backup router receives the ISIS notification message, determines a network segment for DR switching or DR back switching according to the ISIS notification message, and acquires a first interface corresponding to the network segment of the backup router; when the DR requests DR switching, the backup router adjusts the priority of the first interface to be the highest; when the DR requests a DR failover, the backup router adjusts the priority of the first interface to the lowest. Therefore, a new round of election can be directly carried out without waiting for the timing period of the timer to arrive, the time for entering DR election is shortened, DR switching can be rapidly completed, the influence of DR switching on data stream transmission is reduced when DR fails, and back switching can be rapidly carried out after the failed DR is recovered, so that data loss is reduced.

The above-mentioned scheme provided by the embodiment of the present application is introduced mainly from the perspective of interaction between network elements. It is to be understood that each network element, such as DR, backup router, etc., contains corresponding hardware structures and/or software modules for performing each function in order to implement the above-described functions. Those of skill in the art would readily appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiment of the present application, the backup router may be divided into the functional modules according to the above method example, for example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. It should be noted that, in the embodiment of the present application, the division of the module is schematic, and is only one logic function division, and there may be another division manner in actual implementation.

In the case of dividing each functional module by corresponding functions, fig. 4 shows a schematic diagram of a possible structure of the multicast router according to the foregoing embodiment, and the backup router 40 of the present application may include: receiving section 401, determining section 402, acquiring section 403, and adjusting section 404. The receiving unit 401 is configured to support the router to execute the process 302 in fig. 3; determination unit 402 is used to support the backup router to perform other processes of the techniques described herein; the obtaining unit 403 is configured to support the backup router to execute the process 302 in fig. 3; the adjustment unit 404 is used to support the router to perform the process 303 in fig. 3.

With reference to fig. 4, in this embodiment of the application, optionally, the receiving unit may be configured to receive an ISIS notification message sent by the DR, where the ISIS notification message indicates that the DR requests DR handover or DR fallback handover; the determining unit is used for determining a network segment for DR switching or DR back switching according to the ISIS notification message; the acquisition unit is used for acquiring a first interface corresponding to the network segment; an adjusting unit, configured to adjust a priority of the first interface to be highest when the DR requests DR handover; when the DR requests a DR switchback, the priority of the first interface is adjusted to the lowest.

In the case of an integrated unit, fig. 5 shows a possible structural diagram of the backup router involved in the above-described embodiment. For example, processing module 501 is used to support a backup

router performing processes

302 and 303 in fig. 3 and/or other processes for the techniques described herein. The communication module 502 is used to support the router to execute the

processes

301 and 302 in fig. 3, and to backup communication between the router and other network entities, for example, communication between the functional modules or network entities shown in fig. 1. The memory module 503 is used to store program codes and data of the router.

The Processing module 501 may be a Processor or a controller, and may be, for example, a Central Processing Unit (CPU), a general-purpose Processor, a Digital Signal Processor (DSP), an Application-Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, a transistor logic device, a hardware component, or any combination thereof. Which may implement or perform the various illustrative logical blocks, modules, and circuits described in connection with the disclosure. The processor may also be a combination of computing functions, e.g., comprising one or more microprocessors, DSPs, and microprocessors, among others. The communication module 502 may be a transceiver, a transceiving circuit or a communication interface, etc.

Referring to fig. 6, the router 60 includes: a communication interface 601, a processor 602, a memory 603, and a bus 604. Wherein, the communication interface 601, the processor 602 and the memory 603 are connected to each other by a bus 604; the bus 604 may be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is shown in FIG. 6, but this is not intended to represent only one bus or type of bus.

In the embodiment of the present application, functional modules may be divided for DR according to the above method example, for example, each functional module may be divided for each function, or two or more functions may be integrated into one processing module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. It should be noted that, in the embodiment of the present application, the division of the module is schematic, and is only one logic function division, and there may be another division manner in actual implementation.

In the case of dividing the functional modules according to the respective functions, fig. 7 shows a possible structural diagram of the multicast router according to the foregoing embodiment, where the DR70 of the present application may include: a detecting unit 701 and an informing unit 702. The detection unit 701 is configured to support DR to perform the process 301 in fig. 3; the advertising unit 702 is used to support the DR to perform the process 301 in fig. 3.

With reference to fig. 7, in the embodiment of the present application, optionally, the detecting unit is configured to notify the notifying unit when detecting that DR fails or DR recovers; the notification unit is used for sending an ISIS notification message for requesting DR switching to the backup router when the DR failure is detected by the detection unit; and for sending an ISIS advertisement message for requesting a DR cutback to the backup router when the DR restoration is detected by the detection unit.

In the case of integrated units, fig. 8 shows a possible structural representation of the DR involved in the above-described embodiment. For example, processing module 801 is used to support DR for performing process 301 in fig. 3 and/or other processes for the techniques described herein. The communication module 802 is used to support the router to perform the process 301 in fig. 3, and the DR communicates with other network entities, for example, with the functional modules or network entities shown in fig. 1. The storage module 803 is used to store program codes and data of the router.

The Processing module 801 may be a Processor or a controller, such as a Central Processing Unit (CPU), a general-purpose Processor, a Digital Signal Processor (DSP), an Application-Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, a transistor logic device, a hardware component, or any combination thereof. Which may implement or perform the various illustrative logical blocks, modules, and circuits described in connection with the disclosure. The processor may also be a combination of computing functions, e.g., comprising one or more microprocessors, DSPs, and microprocessors, among others. The communication module 802 may be a transceiver, a transceiving circuit or a communication interface, etc.

Referring to fig. 9, the router 90 includes: a communication interface 901, a processor 902, a memory 903, and a bus 904. Wherein, the communication interface 901, the processor 902 and the memory 903 are connected to each other by a bus 904; the bus 904 may be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is shown in FIG. 9, but this does not indicate only one bus or one type of bus.

The steps of a method or algorithm described in connection with the disclosure herein may be embodied in hardware or in software instructions executed by a processor. The software instructions may be comprised of corresponding software modules that may be stored in Random Access Memory (RAM), flash Memory, Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), registers, a hard disk, a removable disk, a compact disc Read Only Memory (CD-ROM), or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Of course, the storage medium may also be integral to the processor. The processor and the storage medium may reside in an ASIC. Additionally, the ASIC may reside in a core network interface device. Of course, the processor and the storage medium may reside as discrete components in a core network interface device.

Those skilled in the art will recognize that in one or more of the examples described above, the functions described herein may be implemented in hardware, software, firmware, or any combination thereof. When implemented in software, the functions may be stored on or transmitted over 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 place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer.

The above description is only an embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions within the technical scope of the present disclosure should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A designated router switching method is applied to a multicast network comprising a designated router DR and a backup router, wherein the backup router and the designated DR run the same ISIS protocol, and the method comprises the following steps:

when the DR detects that the DR is invalid, sending an intermediate system to intermediate system ISIS notification message for requesting DR switching to the backup router; when the DR recovery is detected, sending an ISIS advertisement message for requesting DR back-switching to the backup router, wherein the ISIS advertisement message comprises a message type, an Internet Protocol (IP) address of a second interface and a network mask of the second interface; the message type indicates that the DR requests the DR to switch or requests the DR to switch back; the second interface is an interface for the DR to perform the DR switching or the DR switchback;

the backup router receives the ISIS notification message, determines the network segment of DR switching or DR back switching according to the ISIS notification message, and acquires a first interface corresponding to the network segment of the backup router;

when the DR requests DR switching, the backup router adjusts the priority of the first interface to be the highest; when the DR requests a DR failover, the backup router adjusts the priority of the first interface to be lowest.

2. The method of claim 1, wherein the ISIS advertisement message includes a type-length-value TLV field, the TLV field carrying the message type, the IP address of the second interface, and the network mask.

3. A multicast router acting as a backup router for a designated router DR, the multicast router running the same ISIS protocol as the DR, comprising:

a receiving unit, configured to receive an intermediate system to intermediate system ISIS advertisement message sent by the DR, where the ISIS advertisement message includes a message type, an internet protocol IP address of a second interface, and a network mask of the second interface; the message type indicates that the DR requests the DR to switch or requests the DR to switch back; the second interface is an interface for the DR to perform the DR switching or the DR switchback;

a determining unit, configured to determine, according to the ISIS advertisement message, a network segment where the DR performs DR handover or DR back handover;

the acquisition unit is used for acquiring a first interface corresponding to the network segment;

an adjusting unit, configured to adjust a priority of the first interface to be highest when the DR requests the DR handover; when the DR requests the DR to switch back, the priority of the first interface is adjusted to be the lowest.

4. The multicast router of claim 3, wherein the ISIS advertisement message comprises a type-Length-value TLV field, the TLV field carrying the message type, the Internet protocol IP address of the second interface, and the netmask.

5. A multicast router, wherein the multicast router, as a designated router DR, comprises:

the detection unit is used for notifying the notification unit when the DR is detected to be invalid or recovered;

the notification unit is configured to send an intermediate system to intermediate system ISIS notification message for requesting DR handover to a backup router when the detection unit detects that the DR fails; and is used for sending an ISIS advertisement message for requesting DR cutback to the backup router when the detection unit detects that DR is restored, so that the backup router determines a network segment for DR switching or DR cutback according to the ISIS advertisement message, and acquires a first interface corresponding to the network segment of the backup router, wherein when DR requests DR switching, the backup router adjusts the priority of the first interface to be highest; when the DR requests DR to switch back, the backup router minimizes the priority adjustment value of the first interface;

wherein the DR and the backup router run the same ISIS protocol, and the ISIS advertisement message includes a message type, an Internet Protocol (IP) address of a second interface, and a net mask of the second interface; the message type indicates that the DR requests the DR to switch or requests the DR to switch back; the second interface is an interface for the DR to perform the DR switching or the DR switchback.

6. The multicast router of claim 5, wherein the ISIS advertisement message comprises a type-Length-value TLV field, the TLV field carrying the message type, the Internet protocol IP address of the second interface, and the netmask.

7. Multicast network, characterized in that it comprises a backup router according to claim 3 or 4 and a designated router DR according to claim 5 or 6.