WO2020098611A1

WO2020098611A1 - Method and apparatus for acquiring routing information

Info

Publication number: WO2020098611A1
Application number: PCT/CN2019/117251
Authority: WO
Inventors: 张佳希
Original assignee: 华为技术有限公司
Priority date: 2018-11-16
Filing date: 2019-11-11
Publication date: 2020-05-22
Also published as: CN111200549B; CN111200549A

Abstract

Disclosed are a method and apparatus for acquiring routing information, which solve the problem of operating an NGMVPN in a HoVPN scenario. The specific solution involves: an SPE stores a first import-RT extended group attribute in an import-RT set according to a first RT after receiving the first RT and the first import-RT extended group attribute, and sends the first RT, M import-RT extended group attributes corresponding to the first RT, and a default route corresponding to the first RT. A UPE generates a correlation between the default route and the M import-RT extended group attributes according to the M import-RT extended group attributes corresponding to the first RT and the default route corresponding to the first RT after receiving the first RT, the M import-RT extended group attributes corresponding to the first RT, and the default route corresponding to the first RT.

Description

Method and device for obtaining routing information

This application requires the priority of the Chinese patent application submitted to the State Intellectual Property Office of China on November 16, 2018 with the application number 201811367864.1 and the application name "a method and device for obtaining routing information", the entire content of which is incorporated by reference In this application.

Technical field

This application relates to the field of communications, and in particular to a method and device for obtaining routing information.

Background technique

In the next-generation multicast virtual private network (next-generation multicast virtual private network, NG MVPN) technology, the border gateway protocol (Border Gateway Protocol, BGP) can be used to deliver private network multicast protocol messages and private network multicast Routing effectively simplifies the complexity of network deployment and reduces the difficulty of network maintenance.

VPN technology is widely used in metropolitan area networks. The typical structure of metropolitan area networks is a three-layer model: core layer, convergence layer and access layer. In order to deploy VPN functions in a hierarchical structure network, BGP / MPLS VPN must be changed from a flat model to a hierarchical model, so a hierarchical VPN (hierarchy VPN, HVPN) structure is generated. The core layer includes the network side edge router (network provider edge, NPE). The convergence layer includes an operator-side edge router (service provider-end edge, SPE). The access layer includes the user-side edge router (user provider-end edge, UPE). To reduce the pressure on UPE to store routing information, SPE only publishes default routes to UPE. UPE only maintains user-side routes and does not need to maintain network-side routes. Since the SPE only sends the default route to the UPE, the UPE cannot receive the VPN's Internet Protocol (IP) route and the multicast information (such as extended community attributes) corresponding to the VPN's IP route. However, the operation of NGMVPN requires the use of VPN IP routing and the multicast information corresponding to VPN IP routing, which affects the normal operation of NGMVPN.

Summary of the invention

The embodiments of the present application provide a method and device for obtaining routing information, which solves the problem of how to run NGMVPN in a HoVPN scenario.

To achieve the above purpose, the embodiments of the present application adopt the following technical solutions:

In the first aspect, an embodiment of the present application provides a method for obtaining routing information. The method can be applied to SPE, or the method can be applied to a communication device that can support SPE to implement the method. For example, the communication device includes a chip system. Including: after receiving the first message, the SPE stores the first input route target (import-RT) extended community attribute to the import-RT set according to the first route target (RT), where the first message Including the first RT and the first import-RT extended community attributes; the import-RT set includes the first RT and the M import-RT extended community attributes corresponding to the first RT, and the M import-RT extended community attributes include the first import -RT extended community attribute, M is an integer greater than or equal to 1; then, SPE sends a second packet to UPE, the second packet includes the first RT, the M import-RT extended community attributes and the first The default route corresponding to an RT.

With reference to the first aspect, in a possible implementation manner, the method further includes: the SPE receives the third message and forwards the third message, and the third message includes the second import-RT extended community attribute and multicast information. Among them, the first import-RT extended community attribute includes a global management ID and a local management ID.

In a second aspect, an embodiment of the present application provides a method for obtaining routing information. The method can be applied to UPE, or the method can be applied to a communication device that can support UPE to implement the method. For example, the communication device includes a chip system. Including: after receiving the first message, UPE generates the correspondence between the default route and the M import-RT extended community attributes based on the M import-RT extended community attributes corresponding to the first RT and the default route corresponding to the first RT , Where the first packet includes the first RT, the M import-RT extended community attributes corresponding to the first RT, and the default route corresponding to the first RT.

With reference to the second aspect, in a possible implementation manner, the method further includes: the UPE determines the first import-RT extended community attribute from the M import-RT extended community attributes according to a preset rule; and sends a second packet to the SPE , The second packet includes the first import-RT extended community attribute and multicast information. Among them, the first import-RT extended community attribute includes a global management ID and a local management ID.

With reference to the above possible implementation manners, in another possible implementation manner, UPE determines the first import-RT extended community attribute from M import-RT extended community attributes according to a preset rule, including: UPE according to the global management identifier The size determines the first import-RT extended community attribute from the M import-RT extended community attributes.

In a third aspect, an embodiment of the present application further provides an apparatus for obtaining routing information, for implementing the method described in the first aspect above. The device for obtaining routing information is an SPE or a communication device that supports SPE to implement the method described in the first aspect. For example, the communication device includes a chip system. For example, the device for obtaining routing information includes: a receiving unit, a processing unit, and a sending unit. The receiving unit is configured to receive a first message, and the first message includes a first RT and a first import-RT extended community attribute. The processing unit is configured to store the first import-RT extended community attribute in the import-RT set according to the first RT received by the receiving unit, and the import-RT set includes the first RT and M imports corresponding to the first RT -RT extended community attribute, M import-RT extended community attributes include the first import-RT extended community attribute, and M is an integer greater than or equal to 1. The sending unit is configured to send a second message. The second message includes a first RT, M import-RT extended community attributes corresponding to the first RT, and a default route corresponding to the first RT.

Optionally, the specific processing method is the same as the corresponding description in the first aspect, which will not be repeated here.

In a fourth aspect, an embodiment of the present application further provides an apparatus for obtaining routing information, which is used to implement the method described in the second aspect above. The device for obtaining routing information is UPE or a communication device that supports UPE to implement the method described in the second aspect, for example, the communication device includes a chip system. For example, the device for obtaining routing information includes: a receiving unit and a processing unit. The receiving unit is configured to receive a first message. The first message includes a first RT, M import-RT extended community attributes corresponding to the first RT, and a default route corresponding to the first RT. The processing unit is configured to generate a correspondence between the default route and the M import-RT extended community attributes based on the M import-RT extended community attributes corresponding to the first RT and the default route corresponding to the first RT.

Optionally, the device for obtaining routing information may further include a sending unit, configured to send a second message, where the second message includes the first import-RT extended community attribute and multicast information.

It should be noted that the functional modules of the third aspect and the fourth aspect described above can be implemented by hardware, and can also be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. For example, a transceiver is used to complete the functions of the receiving unit and the sending unit, a processor is used to complete the functions of the processing unit, and a memory is used by the processor to process program instructions of the method of the embodiments of the present application. The processor, transceiver and memory are connected through the bus and complete the communication with each other. Specifically, reference may be made to the function of the behavior of SPE or UPE in the method described in the first aspect to the method described in the second aspect.

In a fifth aspect, an embodiment of the present application further provides an apparatus for obtaining routing information, for implementing the method described in the first aspect above. The device for obtaining routing information is an SPE or a communication device that supports SPE to implement the method described in the first aspect. For example, the communication device includes a chip system. For example, the device for obtaining routing information includes a processor for implementing the functions of the method described in the first aspect. The device for obtaining routing information may further include a memory for storing program instructions and data. The memory is coupled to the processor, and the processor may call and execute program instructions stored in the memory to implement the functions in the method described in the first aspect above. The device for obtaining routing information may further include a communication interface, and the communication interface is used for the device for obtaining routing information to communicate with other devices. Exemplarily, if the device for obtaining routing information is SPE, the other device is UPE.

In a possible device, the device for obtaining routing information includes a communication interface, and the communication interface is used for the device for obtaining routing information to communicate with other devices. Illustratively, the communication interface may be a transceiver. The memory is used to store program instructions. Transceiver, used to receive the first message, the first message includes the first RT and the first import-RT extended community attributes, and sends a second message, the second message includes the first RT, corresponding to the first RT M import-RT extended community attributes and the default route corresponding to the first RT. The processor is configured to store the first import-RT extended community attribute to the import-RT set according to the first RT, and the import-RT set includes the first RT and M import-RT extended community attributes corresponding to the first RT, M Each import-RT extended community attribute includes the first import-RT extended community attribute, and M is an integer greater than or equal to 1.

Optionally, the specific method is the same as the corresponding description in the first aspect, which will not be repeated here.

In a sixth aspect, an embodiment of the present application further provides an apparatus for obtaining routing information, which is used to implement the method described in the second aspect above. The device for obtaining routing information is UPE or a communication device that supports UPE to implement the method described in the second aspect, for example, the communication device includes a chip system. For example, the device for obtaining routing information includes a processor. A processor, configured to implement the functions in the method described in the second aspect above. The device for obtaining routing information may further include a memory for storing program instructions and data. The memory is coupled to the processor, and the processor may call and execute program instructions stored in the memory to implement the functions in the method described in the second aspect above. The device for obtaining routing information may further include a communication interface, and the communication interface is used for the device for obtaining routing information to communicate with other devices. Exemplarily, if the device for obtaining routing information is UPE, the other device is SPE.

In a possible device, the device for obtaining routing information includes a communication interface, and the communication interface is used for the device for obtaining routing information to communicate with other devices. Illustratively, the communication interface may be a transceiver. The transceiver is used to receive a first message, and the first message includes a first RT, M import-RT extended community attributes corresponding to the first RT, and a default route corresponding to the first RT. The memory is used to store program instructions. The processor is configured to generate a correspondence between the default route and the M import-RT extended community attributes according to the M import-RT extended community attributes corresponding to the first RT and the default route corresponding to the first RT.

In a seventh aspect, an embodiment of the present application further provides a computer-readable storage medium, including: computer software instructions; when the computer software instructions run in an apparatus for obtaining routing information, the apparatus for obtaining routing information executes the first aspect described above Or the method described in the second aspect.

In an eighth aspect, an embodiment of the present application further provides a computer program product containing instructions, which, when the computer program product runs in an apparatus for obtaining routing information, causes the apparatus for obtaining routing information to perform the above-mentioned first aspect or second aspect Described method.

In a ninth aspect, an embodiment of the present application provides a chip system. The chip system includes a processor, and may further include a memory, which is used to implement the SPE or UPE function in the foregoing method. The chip system may be composed of chips, or may include chips and other discrete devices.

According to a tenth aspect, an embodiment of the present application further provides a communication system including the SPE described in the third aspect or a communication device supporting SPE to implement the method described in the first aspect, and the UPE or A communication device supporting UPE to implement the method described in the second aspect;

Or the communication system includes the SPE described in the fifth aspect or a communication device supporting SPE to implement the method described in the first aspect, and the UPE described in the sixth aspect or a communication device supporting UPE to implement the method described in the second aspect.

Through the above method, the UPE can receive the first RT sent by the SPE, the M import-RT extended community attributes corresponding to the first RT, and the default route corresponding to the first RT. Since the first RT is used to identify the first VPN, The default route is the default route of the first VPN, so that the UPE can forward the first RT, the M import-RT extended community attributes and the default route corresponding to the first RT to the NPE through the SPE, so that the NPE can perform The information establishes a multicast entry, and forwards the traffic of the first VPN according to the multicast forwarding entry, so as to realize the operation of NGMVPN in the HoVPN scenario.

In addition, for the technical effects brought by the design methods in any of the above aspects, please refer to the technical effects brought by the different design methods in the first and second aspects, which will not be repeated here.

In the embodiments of the present application, the names of the SPE, UPE, the device for obtaining routing information, and the communication device do not limit the device itself. In actual implementation, these devices may appear under other names. As long as the functions of each device are similar to the embodiments of the present application, they fall within the scope of the claims of the present application and their equivalent technologies.

BRIEF DESCRIPTION

FIG. 1 is a simplified structural example of a virtual private network provided by the prior art;

2 is an example diagram of a simplified structure of a BGP / MPLS VPN network provided by the prior art;

3 is an example diagram of a simplified structure of an HVPN provided by the prior art;

4 is an example diagram of a simplified structure of a HoVPN provided by an embodiment of this application;

5 is a flowchart of a method for obtaining routing information provided by an embodiment of the present application;

6 is a flowchart of another method for obtaining routing information provided by an embodiment of the present application;

7 is a schematic diagram of another simplified structure of HoVPN provided by an embodiment of the present application;

8 is a diagram illustrating an example of the composition of an apparatus for obtaining routing information provided by an embodiment of the present application;

9 is a diagram illustrating an example of the composition of another apparatus for obtaining routing information according to an embodiment of this application;

FIG. 10 is a diagram illustrating an example of the composition of another apparatus for obtaining routing information according to an embodiment of the present application.

detailed description

In order to describe the following embodiments clearly and concisely, a brief introduction of related technologies is first given:

Virtual private network (Virtual Private Network, VPN) technology is the technology of a point-to-point private network virtualized on the public data network through the tunnel technology. The basic principle of VPN is to use tunneling technology to encapsulate VPN packets in a tunnel, and use VPN backbone network to establish a dedicated data transmission channel to achieve transparent transmission of packets.

FIG. 1 is a simplified structural example diagram of a virtual private network provided by the prior art. Suppose that an organization has established private network A and private network B in two different locations far apart, and the network address of private network A is private address 10.1.0.0. The network address of the private network B is the private address 10.2.0.0. A VPN needs to be formed between the private network A and the private network B through the public Internet.

As shown in Figure 1, assume that the address of host X is 10.1.0.1 and the address of host Y is 10.2.0.3. If host X sends an IP datagram to host Y, the source address of the IP datagram is 10.1.0.1 and the destination address of the IP datagram is 10.2.0.3. This IP datagram is first sent from the host X to the router R1 connected to the Internet as an internal datagram of the local organization. After receiving the internal datagram, router R1 finds that the destination network of the internal datagram can only be reached through the Internet, encrypts the internal datagram (to ensure the security of the internal datagram), and then adds the header of the datagram again, encapsulating it into the Internet In the external datagram sent on the Internet, the source address of the external datagram is the global address of router R1 125.1.2.3, and the destination address of the external datagram is the global address of router R2 194.4.5.6. After receiving the external datagram, router R2 takes out part of its data and decrypts it to recover the original internal datagram. The destination address of the internal datagram is 10.2.0.3. The internal datagram is forwarded to host Y based on the destination address of the internal datagram. . It should be noted that the transmission of external datagrams from router R1 to router R2 may need to pass through many networks and routers in the Internet, but logically, it seems that there is a straight-through point-to-point link between router R1 and router R2. That is VPN tunnel.

Multi-protocol label switching (MPLS) is a fast forwarding technology that supports multiple network layer protocols. It is an IP high-speed backbone network switching standard proposed by the Internet Engineering Task Force (IETF). It is a system used for rapid packet exchange and routing. It provides destination, routing address, forwarding, and switching capabilities for network data traffic.

Traditional VPNs generally use Generic Routing Encapsulation (GRE) protocol, Layer 2 tunneling protocol (Layer 2 Tunneling Protocol, L2TP), point-to-point tunneling protocol (point to point tunneling protocol, PPTP), Internet protocol security (InternetProtocolSecurity, IPSec) protocol and other tunnel protocols to achieve the transmission of data flow between private networks on the public network. MPLS VPN connects different branches of the private network to form a unified network.

VPN IP routing may refer to VPN-IPv4 routing. The so-called VPN is a collection of several sites. For example, company headquarters and branch offices are sites. BGP / MPLS VPN includes customer network edge (customer edge, CE) router, backbone network edge (provider edge, PE) router and backbone network core (provider, P) router. PE router is the main implementer of BGP / MPLS VPN. The P router is responsible for MPLS forwarding. The backbone network PE router and P router run the public network internal gateway protocol (Interior Gateway Protocol (IGP), public network internal border gateway protocol (Internal, Border Gateway Protocol, IBGP), and configure MPLS LSP for MPLS domain label forwarding. The external border gateway protocol (External Border Gateway Protocol, EBGP) runs between the CE router and the PE router. The CE router is the entrance to the site, and communication between different VPNs is isolated.

Figure 2 is a simplified structural example of a BGP / MPLS VPN network provided by the prior art. The backbone network includes PE router 1, PE router 2, and P router. PE router 1 is connected to CE router 1 and CE router 3. CE Router 1 is the user-side edge router of VPN1. CE router 3 is the user-side edge router of VPN2. PE router 2 connects CE router 2 and CE router 4. CE router 2 is the user-side edge router of VPN1. CE router 4 is the user-side edge router of VPN2. Site 1 and site 2 belong to VPN1, and site 3 belongs to VPN2. Before forwarding IP datagrams, the PE router needs to perform route learning, and then the PE router can forward the IP datagram based on the learned route.

The following is a brief introduction to the route learning process. When CE router 2 learns the route of VPN1 from site 2 according to the BGP / EBGP protocol, EBGP is established between CE router 2 and PE router 2, and CE router 2 uses EBGP to transfer the route of VPN1 from CE router 2 to PE router 2. Assume that the route of VPN1 is 10.1 / 16. After PE router 2 receives the route 10.1 / 16, according to the VPN instance bound to the interface of PE router 2, the route 10.1 / 16 is saved in the virtual routing forwarding (VPN routing and forwarding, VRF) table corresponding to the VPN instance, and is Route 10.1 / 16 is assigned a VPN label, and the VPN label is the inner label. As shown in Table 1, an example diagram of the structure of the VRF table on the egress PE router during the route learning process.

Table 1

PE router 2 saves route 10.1 / 16 to the BGP routing table according to the IBGP routing protocol with PE router 1, and forwards other information related to route 10.1 / 16 to PE router 1, such as the VPN label for route 10.1 / 16 , Routing flag (routedistinguisher, RD) and output routing target (export routing target, export RT). Among them, because the public network cannot distinguish the same routing prefix under multiple VPNs, RD is used to identify different VPN instances on the PE router. RT is used by PE routers to distinguish which VRF table to send to after receiving IP routes of different VPNs. RT is an extended community attribute in BGP. The generation of labels is performed by RT. The PE router relies on the RT attribute to distinguish routes between different VPNs. When exporting VPN IP routes from the VRF table and encapsulating and sending VPN IP routes Use export RT to mark VPN IP routes. When saving VPN IP routes in the VRF table, only the routes with the RT tag that matches any of the input route targets (import RT) in the VRF table will be saved in the VRF table.

After route 10.1 / 16 reaches PE router 1, PE router 1 stores multiple VRF tables. PE router 1 searches in multiple VRF tables based on the export RT to find the import RT that matches the export RT of route 10.1 / 16. And save the route 10.1 / 16 to the VRF table that includes the import RT that matches the export RT. At this time, the RD and the carried VPN label are stripped. As shown in Table 2, an example diagram of the structure of the VRF table imported on the PE router during the route learning process.

Table 2

PE router 1 uses the EBGP protocol to transfer route 10.1 / 16 from PE router 1 to CE router 1. CE router 1 stores the route 10.1 / 16 learned from the EBGP route into the IGP table.

It should be noted that the forwarding of datagrams between two sites belonging to the same VPN uses a two-layer label, that is, the inner PE label and the outer label are marked on the local PE router.

The outer label is used for switching within the backbone network and indicates an LSP from the local PE router to the peer PE router. IP datagrams can use the outer label to reach the peer PE router along the LSP. The backbone network tunnel may be an LSP tunnel, an MPLS traffic engineering (TE) tunnel, or a general routing encapsulation (GRE) tunnel. When the backbone network tunnel is an LSP tunnel or an MPLS TE tunnel, the backbone network label is an MPLS LSP label (the CR-LSP of an MPLS TE tunnel also uses an LSP label). When the backbone network tunnel is a GRE tunnel, the backbone network label is GRE encapsulated.

The inner (private network) label is used when the IP datagram travels from the peer PE router to the peer CE router, indicating which site the packet should be sent to, that is, the private network route allocated for different routes or different VPN instances label. Specifically, when PE routers have mutually advertised VPN IP routes through MP-BGP, the private network label assigned by each private network VPN IP route learned by the local end will be notified to the peer PE router In this way, the peer PE router can find the VPN instance to which the packet belongs according to the private network label carried in the IP datagram, and then forward the IP datagram to the corresponding site by searching the routing table of the VPN instance.

Suppose that Site 1 sends out an IP datagram with a destination address of 10.1.1.1, and CE router 1 sends the IP datagram to PE router 1. After PE router 1 receives the IP datagram, it determines the VPN instance it belongs to based on the incoming interface. In the VRF table corresponding to the example, the route 10.1 / 16 is found. After matching, the VPN label is added. At the same time, PE router 1 serves as the LSR of the MPLS domain, and another layer of LSP label is encapsulated; the IP datagram carries two layers of labels through the MPLS VPN backbone In the network, the outer LSP label is continuously exchanged on the P router. When the IP datagram reaches PE router 2, only the inner label is left; PE router 2 finds the corresponding outgoing interface according to the VPN label and the destination address, and sends the IP datagram To CE router 2, CE router 2 then sends the IP datagram to the destination according to the normal IP forwarding process.

The typical structure of a metropolitan area network is a three-layer model: core layer, convergence layer and access layer. In order to deploy VPN functions in a hierarchical structure network, BGP / MPLS VPN must be changed from a flat model to a hierarchical model, so a hierarchical VPN (hierarchy VPN, HVPN) structure is generated. The core layer includes network side edge (network provider edge, NPE) routers. The convergence layer includes service provider-end edge (SPE) routers. The access layer includes a user-side edge (UPE) router. FIG. 3 is a simplified structural example diagram of an HVPN provided by the prior art.

The default route is a special static route, which refers to the route selected by the router when there is no matching entry in the routing table and the destination address of the IP datagram. In order to reduce the pressure on UPE routers to store routing information, SPE routers can only publish default routes to UPE routers. UPE routers only maintain user-side routes and do not need to maintain network-side routes. In this case, the HVPN implementation can be called HoVPN (hierarchy of VPN).

Multicast VPN (multicast VPN, MVPN) encapsulates private network multicast packets and transmits the private network multicast packets through the multicast tunnels established between the sites to complete the multicast data between the private networks Transmission.

NG MVPN is a new generation framework for IP multicast data traffic traversing BGP / MPLS VPN networks. BGP is used to transfer private network multicast protocol packets and private network multicast routes, which simplifies the network deployment complexity and reduces the difficulty of network maintenance. Make multicast and unicast services in the same VPN architecture. In HoVPN, since the SPE router only sends the default route to the UPE router, the multicast-related information corresponding to the VPN IP route sent by the NPE router cannot be passed to the UPE router, and the UPE router cannot learn the source VPN IP route and VPN IP Multicast information corresponding to the route. However, running the NGMVPN protocol requires the use of VPN IP routing and the multicast information corresponding to the VPN IP routing, which affects the normal operation of NGMVPN.

In order to solve the above problems, the embodiments of the present application provide a method for obtaining routing information. The basic principle is that after the SPE receives the first packet including the first RT and the first import-RT extended community attribute, the SPE RT stores the first import-RT extended community attributes to the import-RT set. The import-RT set includes the first RT and the M import-RT extended community attributes corresponding to the first RT. The M import-RT extended community attributes include The first import-RT extended community attribute, M is an integer greater than or equal to 1; then send a second packet to the UPE, the second packet includes the first RT, the M import-RT extended community attributes and the first The default route corresponding to RT. After receiving the second message, the UPE generates the correspondence between the default route and the M import-RT extended community attributes based on the M import-RT extended community attributes corresponding to the first RT and the default route corresponding to the first RT, and The UPE selects one import-RT extended community attribute from the M import-RT extended community attributes corresponding to the default route and sends it to the SPE. The method for obtaining routing information provided by the embodiment of the present application can use the NGMVPN technology in a HoVPN scenario through the above method.

The terms “first”, “second” and “third” in the specification and claims of the present application and the above-mentioned drawings are used to distinguish different objects, not to define a specific order.

In the embodiments of the present application, words such as "exemplary" or "for example" are used as examples, illustrations or explanations. Any embodiments or design solutions described as “exemplary” or “for example” in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific manner.

The implementation of the embodiments of the present application will be described in detail below with reference to the drawings.

FIG. 4 is a simplified structural example diagram of a HoVPN provided by an embodiment of the present application. SPE routers are connected to NPE router 1, NPE router 2 and UPE router respectively. For convenience, the UPE router is referred to as UPE for convenience. The SPE router is called SPE for short. NPE router 1 is abbreviated as NPE1. As shown in FIG. 5, a flowchart of a method for obtaining routing information provided by an embodiment of the present application, the method may include:

S501. The SPE receives the first message.

The SPE receives the first message sent by NPE1. SPE is the BGP neighbor of NPE1. The first packet may include the IP route of the VPN, the first RT, and the first import-RT extended community attribute. The first message may be an update message specified by the BGP protocol. The update message includes the network layer reachability information (NLRI) field and the extended community attribute field. The IP route of the VPN can be located in the NLRI field. The first RT and the first import-RT extended community attribute may be located in the extended community attribute field. The first RT is used to determine the VPN to receive the first packet. In the following, it is assumed that the IP route of the VPN is the IP route of the first VPN, and the first RT is used to identify the first VPN. The first RT may be an export RT included in the VRF table corresponding to the first VPN. The VRF table corresponding to the first VPN may be stored on NPE1. The VRF table corresponding to the first VPN may be referred to as VRF1 for short. The import-RT extended community attributes include the global administrator ID (global administrator field) and the local administrator ID (local administrator field). The global management identifier is used to represent the unique identifier of the PE in the network. The local management identifier is used to represent the unique identifier of the VPN on the PE. It is assumed that the export RT included in the VRF table corresponding to the first VPN may be (1: 1). NPE1's import-RT extended community attribute can be <3.3.3.3:5>. Among them, 3.3.3.3 represents the global management logo, and 5 represents the local management logo. The import-RT extended community attribute of NPE2 can be <4.4.4.4:2>. Among them, 4.4.4.4 represents the global management ID, and 2 represents the local management ID. It should be noted that the extended community attribute is used for multicast information crossover. Understandably, SPE confirms the reception of multicast information according to the global management identifier included in the import-RT extended community attribute, confirms the crossover to the VPN's VRF table according to the local management identifier included in the import-RT extended community attribute, and establishes multicast entries. When this VPN has corresponding multicast traffic, the VPN forwards according to the established P2MP tunnel. In addition, the IP corresponding to the same VPN has the same RT. Optionally, the first message may include multiple RTs. import-RT In the embodiments of the present application, the messages described below all refer to update messages.

S502. The SPE stores the first import-RT extended community attribute to the import-RT set according to the first RT.

The import-RT set includes the first RT and the M import-RT extended community attributes corresponding to the first RT, where the M import-RT extended community attributes include the first import-RT extended community attribute, and M is greater than or equal to 1. Integer. The M import-RT extended community attributes may also include the import-RT extended community attributes corresponding to the first RT received by the SPE through other messages.

Optionally, the import-RT set may also include other valued RTs, and each RT in the other valued RTs may correspond to at least one import-RT extended community attribute. Understandably, RT may be an index of the import-RT set. After receiving the VPN IP route, the first RT and the first import-RT extended community attribute, the SPE searches the import-RT set according to the first RT and stores the first import-RT extended community attribute under the first RT index .

S503. The SPE sends a second message.

After storing the first import-RT extended community attribute in the import-RT set according to the first RT, the SPE sends a second message to the UPE, where the second message includes the first RT and M imports corresponding to the first RT -RT extended community attribute and default route corresponding to the first RT.

It should be noted that the first RT may be used to determine that the VPN that receives the first packet is the first VPN. The administrator can configure a default route for all BGP neighbors adjacent to the SPE in the first VPN. Therefore, the default route corresponding to the first RT is the default route corresponding to the first VPN. In the embodiment of the present application, the UPE in the second message sent by the SPE to the UPE refers to all BGP neighbors adjacent to the SPE, and all BGP neighbors adjacent to the SPE may be one or two or more than two . If all BGP neighbors adjacent to the SPE are one UPE, the SPE can send a second packet to the one UPE; if all BGP neighbors adjacent to the SPE are two or more UPEs, the SPE can send the two or More than two UPEs send the second message. It should be noted that one default route corresponds to one VPN. Understandably, SPE needs to send a default route for different VPNs.

S504. The UPE receives the second message.

S505. The UPE generates a correspondence between the default route and the M import-RT extended community attributes according to the M import-RT extended community attributes corresponding to the first RT and the default route corresponding to the first RT.

For example, you can use a list structure to store, the list uses the import-RT logo as a key value, which is convenient for finding the content in the list. As shown in Table 3, the correspondence between the default route and the import-RT extended community attribute.

table 3

Therefore, the SPE passes the first RT, the M import-RT extended community attributes corresponding to the first RT, and the default route corresponding to the first RT to the UPE. Since the first RT is used to identify the first VPN, the default route is the first The default route of a VPN enables UPE to recognize the received M import-RT extended community attributes according to the first RT.

Further, after the UPE generates the correspondence between the default route and the M import-RT extended community attributes based on the M import-RT extended community attributes corresponding to the first RT and the default route corresponding to the first RT, that is, after S505, such as As shown in FIG. 6, the embodiment of the present application further includes the following steps.

S601. UPE saves the default route to the VRF table according to the first RT.

UPE searches for import-RT matching the first RT in multiple VRF tables according to the first RT, and after finding the VRF table including the import-RT matching the first RT, saves the default route to include the first RT matches the import-RT VRF table.

S602. The UPE obtains the multicast entry corresponding to the first VPN and the default route in the VRF table.

Multicast entries can be established through Protocol Independent Multicast (PIM) protocol. The multicast entries in the embodiments of the present application may refer to (S, G) routing entries. The specific method for the UPE to establish the multicast entry according to the PIM protocol can refer to the prior art, and the embodiments of the present application will not repeat them here. The PIM protocol indicates that a unicast routing table generated by a static route or any unicast routing protocol can be used to provide a route for IP multicast. Therefore, if a site in the VPN needs to receive multicast traffic, UPE can obtain the (S, G) entry corresponding to the VPN. The (S, G) entry includes the multicast source and the multicast group. Since the UPE also stores the same VRF table corresponding to VPN, UPE can also obtain unicast route through VRF table corresponding to the same VPN, so that unicast route can be used to obtain multicast traffic of multicast source.

If the site in the first VPN needs to receive multicast traffic, the UPE can obtain the multicast source and the multicast group in the (S, G) entry of the first VPN. Since the unicast route stored in the VRF table corresponding to the first VPN is the learned default route, UPE can obtain the default route in the VRF table corresponding to the first VPN, so that the UPE uses the default route to obtain the multicast of the multicast source flow.

S603. UPE obtains M import-RT extended community attributes corresponding to the first RT according to the default route corresponding to the first RT.

Since the UPE pre-stores the correspondence between the default route and the M import-RT extended community attributes, the UPE can obtain the M import-RT extended community attributes corresponding to the first RT according to the default route corresponding to the first RT.

S604. The UPE determines the second import-RT extended community attribute from the M import-RT extended community attributes according to a preset rule.

The second import-RT extended community attribute determined by the UPE from the M import-RT extended community attributes according to a preset rule may be the same as the first import-RT extended community attribute received by the SPE through the first message, or may be different.

For example, UPE may determine an import-RT extended community attribute from M import-RT extended community attributes according to the global management identifier included in the import-RT extended community attribute. For example, select the import-RT extended community attribute that includes the minimum global management ID. Or, select the import-RT extended community attribute that includes the largest global management ID. This embodiment of the present application does not limit this. Assuming that the first import-RT extended community attribute is <3.3.3.3:5> and the second import-RT extended community attribute is <4.4.4.4:2>, UPE can select <3.3.3.3:5>. Of course, an import-RT extended community attribute may also be determined from the M import-RT extended community attributes according to the local management identifier included in the import-RT extended community attribute.

S605. UPE sends a third message.

The third message includes the first import-RT extended community attribute and multicast information. The multicast information may be located in the NLRI field included in the third message. The first import-RT extended community attribute may be located in the extended community attribute field included in the third message. Multicast information includes multicast sources and multicast groups. In the embodiment of the present application, it is assumed that the multicast information is the multicast information of the first VPN, and the multicast information includes the multicast source and the multicast group of the first VPN. In practical applications, multicast information may also include RD and source autonomous system (AS). The third packet described in the embodiment of the present application may refer to a C-multicast route.

S606. The SPE receives the third message.

After receiving the third message, the SPE forwards the third message to the BGP neighbor NPE adjacent to the SPE. After receiving the multicast information, the NPE checks the first import-RT extended community attribute. Assume that the first import-RT extended community attribute is <3.3.3.3:5>. The NPE confirms receiving the multicast information according to the global management identifier 3.3.3.3, and confirms to cross under the VRF table of the first VPN according to the local management identifier 5, and establishes a multicast entry. When the first VPN has corresponding multicast traffic, it will According to the established P2MP tunnel forwarding. Therefore, when there are multiple NPEs, the NPE after receiving the multicast information can identify whether the multicast information should be handled by itself, and which of its own VRF tables the multicast information should cross to.

For the method for obtaining routing information between UPE, SPE, and NPE2, reference may be made to the above description on the transmission of obtaining routing information between UPE, SPE, and NPE1, which is not limited in the embodiments of the present application.

It should be noted that when the NPE fails, the IP route of the VPN learned by the NPE needs to be revoked. After the SPE adjacent to the NPE senses that the route is revoked, the corresponding import-RT set is refreshed, and the UPE updates the import-RT set. After that, recalculate the preferred attributes and send C multicast routing traffic.

Optionally, two NPEs can also be linked to UPE through two SPEs, configure HoVPN and deploy NGMVPN dual-root 1 + 1 protection scenarios. 7 is a schematic diagram of another simplified structure of HoVPN provided by an embodiment of the present application. SPE1 is connected to NPE1 and UPE1 respectively. SPE2 is connected to NPE2 and UPE2 respectively. SPE1 and SPE2 are connected. UPE1 is connected to UPE2. NPE1 and NPE2 are connected.

SPE1 can receive not only the first packet sent by NPE1, but also the second packet sent by NPE2 forwarded by SPE2. The first packet includes the IP routing of the first VPN, the first RT, and the first import-RT extension Group attributes. The first RT may be (1: 1). The first import-RT extended community attribute may be <3.3.3.3:5>. The second packet includes the IP route of the first VPN, the first RT and the second import-RT extended community attribute. The second import-RT extended community attribute may be <4.4.4.4:2>. After SPE1 receives the first message and the second message, SPE1 stores the first import-RT extended community attribute and the second import-RT extended community attribute to the import-RT set according to the first RT, and sends a third packet , The third packet includes the first RT, the Q import-RT extended community attributes and the default route corresponding to the first RT. Similarly, SPE2 stores the first import-RT extended community attribute and the second import-RT extended community attribute to the import-RT set according to the first RT, and sends a fourth packet, the fourth packet includes the first RT, the first Q import-RT extension community attributes and default routes corresponding to RT. Q is an integer greater than or equal to 1. For detailed explanations, reference may be made to the detailed explanations of S502 and S503, and the embodiments of the present application will not be repeated here.

In this dual-homing SPE scenario, UPE1 can learn two default routes with different next hops and import-RT extended community attributes. The default routes can form fast reroute (FRR). FRR is a technology that realizes partial network protection in MPLS TE. Only interfaces with a rate above 100Mbps support FRR. The switching speed of FRR can reach 50 milliseconds, which can minimize the loss of data during network failure.

UPE1 receives the third packet and the fourth packet, that is, after receiving the first RT and the Q import-RT extended community attributes and the default route corresponding to the first RT, the default route is stored according to the first RT and a default route is generated Correspondence with Q import-RT extended community attributes. For detailed explanations, reference may be made to the detailed explanations of S505 and S601, and the embodiments of the present application will not be repeated here. It should be noted that UPE1 needs to generate a correspondence between the default route and the Q import-RT extended community attributes for each default route with the import-RT extended community attribute.

UPE1 queries the FRR scenario where the source or unicast route is the default route when generating the C multicast route. Each default route is encapsulated by the C-multicast route through the import-RT extended community attribute of policy optimization. It should be noted that the import-RT extended community attributes of the IP routing of the two VPNs should be treated exclusively. For example, the primary path preferred import-RT extended community attribute operation may be performed first. When the backup path is preferred, the primary path preferred import-RT extended community attribute shall be excluded to ensure that two different roots are selected to form a 1 + 1 protection scenario.

SPE1 receives the C multicast route and forwards it to the NPE1 device. NPE1 and NPE2 confirm that both the entry-RT extended community attribute establishes the entry traffic and corresponds to the P2MP tunnel forwarding. UPE selectively receives the traffic according to the active-standby relationship, that is, UPE receives the same Multicast traffic, then the master and backup of the data routing choose a copy to forward to the CE, a simple description is the double-receiving and selective sending. For detailed steps, reference may be made to the prior art embodiments of the present application, and details are not described herein again. In addition, for the relevant steps of UPE2, SPE2, and NPE2, reference may be made to the descriptions of UPE1, SPE1, and NPE1, and the embodiments of the present application will not repeat them here.

In the above embodiments provided by the present application, the methods provided by the embodiments of the present application are introduced from the perspectives of SPE, UPE, and the interaction between SPE and UPE. It can be understood that, in order to implement various functions in the method provided by the embodiments of the present application, various network elements, such as SPE and UPE, include hardware structures and / or software modules corresponding to performing each function. Those skilled in the art should easily realize that, in combination with the algorithm steps of the examples described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed by hardware or computer software driven hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

The embodiments of the present application may divide the functional modules of the SPE and UPE according to the above method examples. 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 above integrated modules may be implemented in the form of hardware or software function modules. It should be noted that the division of the modules in the embodiments of the present application is schematic, and is only a division of logical functions. In actual implementation, there may be another division manner.

In the case where each functional module is divided according to each function, FIG. 8 shows a schematic diagram of a possible composition of the device for obtaining routing information mentioned above and in the embodiments, and the device for obtaining routing information can execute each method of the present application. The steps performed by the SPE in any of the method embodiments. As shown in FIG. 8, the device for obtaining routing information is SPE or a communication device that supports SPE to implement the method provided in the embodiment. For example, the communication device may be a chip system. The device for obtaining routing information may include a receiving unit 801, a processing unit 802, and a sending unit 803.

Among them, the receiving unit 801 is used to support a device for obtaining routing information to execute the method described in the embodiments of the present application. For example, the receiving unit 801, the device for performing or for supporting obtaining routing information executes S501 in the method for obtaining routing information shown in FIG. 5, and S501 and S606 in the method for obtaining routing information shown in FIG. 6.

The processing unit 802 is configured to execute or support an apparatus for acquiring routing information to execute S502 in the method for acquiring routing information shown in FIG. 5 and S502 in the method for acquiring routing information shown in FIG. 6.

The sending unit 803 is configured to perform or support an apparatus for acquiring routing information to execute S503 in the method for acquiring routing information shown in FIG. 5 and S503 in the method for acquiring routing information shown in FIG. 6.

It should be noted that all relevant content of the steps involved in the above method embodiments can be referred to the function description of the corresponding function module, which will not be repeated here.

The apparatus for obtaining routing information provided by the embodiments of the present application is used to execute the method of any of the above embodiments, and therefore can achieve the same effect as the method of the above embodiments.

In the case where each functional module is divided corresponding to each function, FIG. 9 shows a schematic diagram of a possible composition of the device for obtaining routing information mentioned above and in the embodiment, and the device for obtaining routing information can execute each method of the present application. The steps performed by the UPE in any method embodiment of the embodiments. As shown in FIG. 9, the device for obtaining routing information is UPE or a communication device supporting UPE to implement the method provided in the embodiment, for example, the communication device may be a chip system. The device for obtaining routing information may include a receiving unit 901 and a processing unit 902.

Among them, the receiving unit 901 is used to support the device for obtaining routing information to execute the method described in the embodiments of the present application. For example, the receiving unit 901, the device for performing or for supporting obtaining routing information executes S504 in the method for obtaining routing information shown in FIG. 5, and S504 in the method for obtaining the routing information shown in FIG. 6.

The processing unit 902 is configured to execute or support an apparatus for acquiring routing information to execute S505 in the method for acquiring routing information shown in FIG. 5, and S505 and S601 to S604 in the method for acquiring routing information shown in FIG. 6.

In the embodiment of the present application, further, as shown in FIG. 9, the communication device may further include: a sending unit 903.

The sending unit 903 is configured to execute or to support an apparatus for acquiring routing information to execute S605 in the method for acquiring routing information shown in FIG. 6.

As shown in FIG. 10, an apparatus 1000 for obtaining routing information provided by an embodiment of the present application is used to implement the function of the SPE in the foregoing method. The device 1000 for obtaining routing information may be an SPE or a device in the SPE. The device 1000 for obtaining routing information may be a chip system. In the embodiment of the present application, the chip system may be composed of a chip, or may include a chip and other discrete devices. Alternatively, the device 1000 for obtaining routing information is used to implement the UPE function in the above method. The device 1000 for obtaining routing information may be a UPE or a device in the UPE. The device 1000 for obtaining routing information may be a chip system. In the embodiment of the present application, the chip system may be composed of a chip, or may include a chip and other discrete devices.

The device 1000 for obtaining routing information includes at least one processor 1001 for implementing the functions of SPE or UPE in the method provided by the embodiments of the present application. Exemplarily, the processor 1001 may be used to store the first import-RT extended community attribute to the import-RT set according to the first RT, and save the default route to the VRF table according to the first RT, and generate the default route and M number For the correspondence between the import-RT extended community attributes and so on, please refer to the detailed description in the method example for details, which will not be repeated here.

The device 1000 for obtaining routing information may further include at least one memory 1002 for storing program instructions and / or data. The memory 1002 and the processor 1001 are coupled. The coupling in the embodiments of the present application is an indirect coupling or communication connection between devices, units or modules, which may be in electrical, mechanical or other forms, and is used for information interaction between devices, units or modules. The processor 1001 may cooperate with the memory 1002. The processor 1001 may execute program instructions stored in the memory 1002. At least one of the at least one memory may be included in the processor.

The device 1000 for obtaining routing information may further include a communication interface 1003 for communicating with other devices through a transmission medium, so that the device in the device 1000 for obtaining routing information can communicate with other devices. Exemplarily, if the device for obtaining routing information is SPE, the other device is UPE. If the device for obtaining routing information is UPE, the other device is SPE. The processor 1001 uses the communication interface 1003 to send and receive data, and is used to implement the method performed by the SPE or UPE described in the embodiments corresponding to FIG. 5 and FIG. 6.

The embodiments of the present application do not limit the specific connection media between the communication interface 1003, the processor 1001, and the memory 1002. In the embodiment of the present application, in FIG. 10, the communication interface 1003, the processor 1001, and the memory 1002 are connected by a bus 1004. The bus is shown by a thick line in FIG. 10, and the connection mode between other components is only for schematic illustration. , Not to limit. The bus can be divided into an address bus, a data bus, and a control bus. For ease of representation, only a thick line is used in FIG. 10, but it does not mean that there is only one bus or one type of bus.

In the embodiments of the present application, the processor may be a general-purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, which may be Perform the disclosed methods, steps, and logical block diagrams in the embodiments of the present application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in conjunction with the embodiments of the present application may be directly embodied and executed by a hardware processor, or may be executed and completed by a combination of hardware and software modules in the processor.

In the embodiment of the present application, the memory may be a non-volatile memory, such as a hard disk (HDD) or a solid-state drive (SSD), etc., or a volatile memory (volatile memory), for example Random access memory (random-access memory, RAM). The memory is any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory in the embodiment of the present application may also be a circuit or any other device capable of realizing a storage function, which is used to store program instructions and / or data.

Through the description of the above embodiments, those skilled in the art can clearly understand that, for convenience and conciseness of description, only the above-mentioned division of each functional module is used as an example for illustration. In practical applications, the above-mentioned functions can be allocated as needed It is completed by different functional modules, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

In the several embodiments provided in this application, it should be understood that the disclosed device and method may be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules or units is only a division of logical functions. In actual implementation, there may be other divisions, for example, multiple units or components may be The combination can either be integrated into another device, or some features can be ignored, or not implemented. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components displayed as units may be one physical unit or multiple physical units, that is, may be located in one place, or may be distributed in multiple different places . Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

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

The methods provided in the embodiments of the present application may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on the computer, all or part of the processes or functions according to the embodiments of the present invention are generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, a network device, a terminal, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be from a website site, computer, server or data center Transmission to another website, computer, server or data center via wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device including a server, a data center, and the like integrated with one or more available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), optical medium (e.g., digital video disc (DVD)), or semiconductor medium (e.g., SSD), or the like.

The above is only the specific implementation of this application, but the scope of protection of this application is not limited to this, any changes or replacements within the technical scope disclosed in this application should be covered within the scope of protection of this application . Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

A method for obtaining routing information, which includes:

The operator-side edge router SPE receives the first message, where the first message includes the first routing target RT and the first input routing target import-RT extended community attribute;

The SPE stores the first import-RT extended community attribute to an import-RT set according to the first RT, where the import-RT set includes the first RT and M corresponding to the first RT import-RT extended community attribute, the M import-RT extended community attributes include the first import-RT extended community attribute, and M is an integer greater than or equal to 1;

The SPE sends a second message, where the second message includes the first RT, the M import-RT extended community attributes, and a default route corresponding to the first RT.
The method according to claim 1, wherein the method further comprises:

The SPE receives a third message, where the third message includes the second import-RT extended community attribute and multicast information;

The SPE forwards the third message.
The method according to claim 2, wherein the first RT is used to identify a first VPN, the default route is a default route of the first VPN, and the multicast information is the first VPN Multicast information, the multicast information includes a multicast source and a multicast group.
A method for obtaining routing information, characterized in that the method includes:

The user-side edge router UPE receives a first packet, the first packet includes a first routing target RT, M input routing targets corresponding to the first RT, an import-RT extended community attribute, and the first RT Corresponding default route, M is an integer greater than or equal to 1;

The UPE generates a correspondence between the default route and the M import-RT extended community attributes according to the M import-RT extended community attributes corresponding to the first RT and the default route corresponding to the first RT .
The method according to claim 4, wherein the method further comprises:

The UPE determines the first import-RT extended community attribute from the M import-RT extended community attributes according to a preset rule;

The UPE sends a second message, where the second message includes the first import-RT extended community attribute and multicast information.
The method according to claim 5, wherein the UPE determining the first import-RT extended community attribute from the M import-RT extended community attributes according to a preset rule includes:

The UPE determines the first import-RT extended community attribute from the M import-RT extended community attributes according to the size of the global management identifier.
The method according to any one of claims 4-6, wherein the first RT is used to identify a first VPN, the default route is a default route of the first VPN, and the multicast information Is the multicast information of the first VPN, and the multicast information includes a multicast source and a multicast group.
An apparatus for obtaining routing information is characterized by comprising:

A receiving unit, configured to receive a first message including a first routing target RT and a first input routing target import-RT extended community attribute;

A processing unit, configured to store the first import-RT extended community attribute to an import-RT set according to the first RT received by the receiving unit, the import-RT set including the first RT and the M import-RT extended community attributes corresponding to the first RT, the M import-RT extended community attributes include the first import-RT extended community attributes, and M is an integer greater than or equal to 1;

The sending unit is configured to send a second message, where the second message includes the first RT, the M import-RT extended community attributes, and a default route corresponding to the first RT.
The device according to claim 8, characterized in that

The receiving unit is further configured to receive a third message, where the third message includes the second import-RT extended community attribute and multicast information;

The sending unit is also used to forward the third message.
The apparatus according to claim 9, wherein the first RT is used to identify a first VPN, the default route is a default route of the first VPN, and the multicast information is the first VPN Multicast information, the multicast information includes a multicast source and a multicast group.
An apparatus for obtaining routing information is characterized by comprising:

A receiving unit, configured to receive a first message including a first routing target RT, M input routing targets corresponding to the first RT, import-RT extended community attributes, and the first RT Corresponding default route, M is an integer greater than or equal to 1;

The processing unit is configured to generate the default route and the M import-RT extended community attributes based on the M import-RT extended community attributes corresponding to the first RT and the default route corresponding to the first RT Correspondence.
The device according to claim 11, characterized in that

The processing unit is further configured to determine the first import-RT extended community attribute from the M import-RT extended community attributes according to a preset rule;

The device also includes a sending unit,

The sending unit is configured to send a second message, where the second message includes the first import-RT extended community attribute and multicast information.
The apparatus according to claim 12, wherein the processing unit is configured to:

The first import-RT extended community attribute is determined from the M import-RT extended community attributes according to the size of the global management identifier.
The device according to any one of claims 11 to 13, wherein the first RT is used to identify a first VPN, the default route is a default route of the first VPN, and the multicast information Is the multicast information of the first VPN, and the multicast information includes a multicast source and a multicast group.
An apparatus for obtaining routing information, comprising: at least one processor, a memory, and a transceiver, wherein the memory is used to store a computer program, so that the computer program is implemented when executed by the at least one processor The method for obtaining routing information according to any one of claims 1-3 or the method for obtaining routing information according to any one of claims 4-7.
A computer-readable storage medium, characterized by comprising: computer software instructions;

When the computer software instruction runs in a device that obtains routing information or a chip built into the device that obtains routing information, causes the device that obtains routing information to perform the route obtaining according to any one of claims 1-3 The method for information or the method for obtaining routing information according to any one of claims 4-7.
A computer program product containing instructions, characterized in that when the computer program product runs in a chip of a device for obtaining routing information or a chip built in a device for obtaining routing information, the device for obtaining routing information is executed The method for obtaining routing information according to any one of claims 1-3 or the method for obtaining routing information according to any one of claims 4-7.