CN105207909A

CN105207909A - Method for transmitting information and network apparatus

Info

Publication number: CN105207909A
Application number: CN201410287382.0A
Authority: CN
Inventors: 牛乐宏; 徐卫平; 白旭辉
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2014-06-24
Filing date: 2014-06-24
Publication date: 2015-12-30
Anticipated expiration: 2034-06-24
Also published as: WO2015196923A1; CN105207909B

Abstract

The invention relates to a method for transmitting information and a network apparatus and belongs to the communication field. The method comprises the following steps that: SR attribute information transmitted by a service router (SR) is received, wherein the SR attribute information at least comprises the identifier of the SR; topological configuration information is acquired, wherein the topological configuration information comprises the SR attribute information and the identifier of a service node (SN) contained in the network apparatus; and the topological configuration information is transmitted to a business chain control system. The device comprises a receiving module, an acquiring module and a transmitting module. With the method of the invention adopted, service chain network topology generation efficiency can be improved.

Description

Method for sending information and network device

Technical Field

The present invention relates to the field of communications, and in particular, to a method and a network device for sending information.

Background

In a data center network or an Internet network, in order to support better service experience, a servicechain network needs to be deployed in the network. The servicechain network includes a service chain control system (servicechain manager in english), one or more SRs (service routers), and one or more SNs (service nodes) attached to the SRs, and the service chain control system maintains and manages the SNs and the SRs included in the servicechain network. The service chain control system needs to maintain and manage the servicechain network depending on the servicechain network topology. Therefore, before maintaining and managing the servicechain network, the service chain control system needs to generate the servicechain network topology.

At present, there is a scheme for generating a servicechain network topology, which may be: a technician manually configures an SN-SR attachment relation table corresponding to each SR in the servicechain network, where the SN-SR attachment relation table corresponding to the SR includes an identifier of the SR and an identifier of an SN bound to the SR. And the technical personnel records the SN corresponding to each SR and the SR attachment relation table into the service chain control system. Further, the technician may also enter SR attribute information of each SR into the service chain control system, where the SR attribute information of the SR includes a management IP (internet protocol, protocol for interconnection between networks) address of the SR, a UUID (universally unique identifier) of the SR, an interface type of the SR, an interface number of the SR, the number of flow tables supported by the SR, and/or the number of SNs supported by the SR. And the service chain control system generates a servicechain network topology according to the SN corresponding to each SR and SR attachment relation table and/or the SR attribute information of each SR.

In the process of implementing the invention, the inventor finds that the related art has at least the following problems:

when the number of the SRs is large, for example, hundreds of the SRs, the efficiency of generating the servicechain network topology is low because a technician manually enters the attachment relationship table between the SN and the SR corresponding to each SR and/or the SR attribute information of each SR.

Disclosure of Invention

In order to solve the problems of the related art, embodiments of the present invention provide a method and a network device for sending information. The technical scheme is as follows:

in a first aspect, a network device, the network device comprising:

a receiving module, configured to receive SR attribute information sent by a service router SR, where the SR attribute information at least includes an identifier of the SR;

an obtaining module, configured to obtain topology configuration information, where the topology configuration information includes the SR attribute information and an identifier of an SN included in the network device;

and the sending module is used for sending the topology configuration information to a service chain control system.

With reference to the first aspect, in a first possible implementation manner of the first aspect, the receiving module is configured to receive a link layer discovery protocol LLDP packet that carries SR attribute information and is sent by a service router SR, and extract the SR attribute information from a data unit of the LLDP packet.

With reference to the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, the receiving module is specifically configured to receive a link layer discovery protocol LLDP packet sent by a service router SR, determine that the LLDP packet carries SR attribute information if a reserved bit in a system capability field of the LLDP packet is set, and extract the SR attribute information from a data unit of the LLDP packet.

With reference to the first aspect, in a third possible implementation manner of the first aspect, the topology configuration information at least includes an SN and SR attachment relationship;

the acquisition module includes:

a selection submodule, configured to select an identifier of an SN from an SN list, where the SN list is used to store the identifier of the SN attached to the SR;

and the establishing submodule is used for establishing an SN and SR attachment relation according to the selected SN identifier and the SR attribute information, wherein the SN and SR attachment relation comprises the SR identifier and the selected SN identifier.

With reference to the first aspect, in a fourth possible implementation manner of the first aspect, the selecting sub-module is configured to select the identifiers of all SNs included in the SN list; or, if the SR attribute information includes the SN number supported by the SR, selecting an identifier of an SN from the SN list according to the SN number supported by the SR.

With reference to the first aspect, in a fifth possible implementation manner of the first aspect, the sending module is specifically configured to call a function for reading information from a preset function library; and storing the topology configuration information in a management component on the network device through the function, wherein the management component comprises an open interface, and the open interface is used for transmitting the topology configuration information stored in the management component to the service chain control system after being called by the service chain control system.

With reference to the first aspect or any one of the first to fifth possible implementation manners of the first aspect, in a sixth possible implementation manner of the first aspect, the SR attribute information further includes any one or more of an interface type of the SR, an interface number of the SR, a number of flow tables supported by the SR, and a number of SNs supported by the SR.

In a second aspect, a method of transmitting information, the method comprising:

receiving SR attribute information sent by a service router SR, wherein the SR attribute information at least comprises an identifier of the SR;

acquiring topology configuration information, wherein the topology configuration information comprises the SR attribute information and an identifier of a Service Node (SN) included by a network device;

and sending the topology configuration information to a service chain control system.

With reference to the second aspect, in a first possible implementation manner of the second aspect, the receiving SR attribute information sent by the service router SR includes:

receiving a Link Layer Discovery Protocol (LLDP) message which is sent by a Service Router (SR) and carries SR attribute information;

and extracting SR attribute information from the data unit of the LLDP message.

With reference to the first possible implementation manner of the second aspect, in a second possible implementation manner of the second aspect, the receiving a link layer discovery protocol LLDP packet that carries SR attribute information and is sent by a service router SR includes:

receiving a Link Layer Discovery Protocol (LLDP) message sent by a Service Router (SR);

and if the reserved bit position in the system capability field of the LLDP message is set, determining that the LLDP message carries SR attribute information.

With reference to the second aspect, in a third possible implementation manner of the second aspect, the topology configuration information at least includes an SN and SR attachment relationship;

the acquiring topology configuration information includes:

selecting an identification of a SN from a list of SNs storing identifications of SNs included by the network device;

and establishing an SN and SR attachment relation according to the selected SN identifier and the SR attribute information, wherein the SN and SR attachment relation comprises the SR identifier and the selected SN identifier.

With reference to the second aspect or the third possible implementation manner of the second aspect, in a fourth possible implementation manner of the second aspect, the selecting an identifier of a SN from a SN list includes:

selecting the identifications of all SNs included in the SN list; or,

and if the SR attribute information comprises the SN number supported by the SR, selecting the SN identifier from the SN list according to the SN number supported by the SR.

With reference to the second aspect, in a fifth possible implementation manner of the second aspect, the sending the topology configuration information to a service chain control system includes:

calling a function for reading information from a preset function library;

and storing the topology configuration information in a management component on the network device through the function, wherein the management component comprises an open interface, and the open interface is used for transmitting the topology configuration information stored in the management component to the service chain control system after being called by the service chain control system.

With reference to the second aspect or any one of the first to fifth possible implementation manners of the second aspect, in a sixth possible implementation manner of the second aspect, the SR attribute information further includes any one or more of an interface type of the SR, an interface number of the SR, a number of flow tables supported by the SR, and a number of SNs supported by the SR.

In a third aspect, a network device comprising a memory, a processor, and one or more programs, wherein the one or more programs are stored in the memory, and configured for execution by the processor the one or more programs include instructions for:

In the embodiment of the invention, SR attribute information sent by an SR is received, and topology configuration information is obtained, wherein the topology configuration information comprises the SR attribute information and an identifier of an SN attached to the SR; and sending the topology configuration information to a service chain control system, so that the service chain control system generates a service chain network topology according to the topology configuration information. Through the processing mode, the service chain control system can automatically acquire the topology configuration information and generate the service chain network topology according to the topology configuration information. Thus, the efficiency of generating the servicechain network topology is improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

fig. 1 is a schematic diagram of a network architecture according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a network device according to an embodiment of the present invention.

Fig. 3 is a flowchart of a method for sending information according to an embodiment of the present invention.

Fig. 4-1 is a flowchart of another method for sending information according to an embodiment of the present invention.

Fig. 4-2 is a schematic diagram of a LLDP (link layer discovery protocol) message structure provided in the embodiment of the present invention.

Fig. 4-3 is a schematic structural diagram of a system capability TLV (Type-length-value) according to an embodiment of the present invention.

Fig. 4-4 are schematic structural diagrams of a system attribute TLV according to an embodiment of the present invention.

Fig. 4-5 are schematic diagrams of service chain network topologies provided by embodiments of the present invention.

Fig. 5 is a schematic structural diagram of another network device according to an embodiment of the present invention.

With the above figures, certain embodiments of the invention have been illustrated and described in more detail below. The drawings and the description are not intended to limit the scope of the inventive concept in any way, but rather to illustrate it by those skilled in the art with reference to specific embodiments.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the following embodiments and accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.

In order to support better service experience in a data center network or an Internet network, a servicechain network needs to be deployed in the network.

Referring to the servicechain network architecture shown in fig. 1, the servicechain network includes a service control system, one or more SRs, and a server connected to the SRs, where one or more SNs are deployed.

The service chain control system is used for creating SN in the server, maintaining servicechain network topology, configuring a forwarding table for each SR according to the servicechain network topology, and the like.

The SR is used for receiving the message and forwarding the message to the SN attached to the SR or the SR connected with the SN according to the forwarding table stored by the SR. In a servicechain network, the SR may be deployed on a physical switch.

The SN is used for receiving the message forwarded by the SR and processing the message. The SN may be implemented in a VM (virtual machine). For example, assuming that the SN is a firewall, the SN may perform enhanced processing on the received message.

The service chain control system needs to configure a forwarding table for each SR according to the servicechain network topology, so the servicechain network topology is very important for realizing the functions of the servicechain network, and therefore, in the invention, the servicechain network topology can be generated through the following embodiments.

Referring to fig. 2, an embodiment of the present invention provides a network apparatus, including:

a receiving module 201, configured to receive SR attribute information sent by an SR, where the SR attribute information at least includes an identifier of the SR;

an obtaining module 202, configured to obtain topology configuration information, where the topology configuration information includes the SR attribute information and an identifier of an SN included in a network device;

a sending module 203, configured to send the topology configuration information to a service chain control system.

The service chain control system receives topology configuration information sent by each network device in the Servicechain network, and generates a Servicechain network topology according to each received topology configuration information.

Preferably, the receiving module 201 is configured to receive an LLDP packet which is sent by an SR and carries SR attribute information, and extract the SR attribute information from a data unit of the LLDP packet.

Preferably, the receiving module 201 is specifically configured to receive an LLDP message sent by an SR, determine that the LLDP message carries SR attribute information if a reserved bit in a system capability field of the LLDP message is set, and extract the SR attribute information from a data unit of the LLDP message.

When the SR sends its own SR attribute information, a bit may be selected from reserved bits of a system capability field of the LLDP message, the selected bit is set, the set bit is used to indicate that a data unit of the LLDP message carries the SR attribute information, and then the data unit of the LLDP message is set to carry the SR attribute information, and the LLDP message is sent.

Wherein, the topology configuration information at least comprises SN and SR attachment relation;

preferably, the obtaining module 202 includes:

a selection submodule, configured to select an identifier of a SN from a SN list, where the SN list is used to store identifiers of SNs included in the network device;

Further, the topology configuration information may further include any one or more of an interface type of the SR, an interface number of the SR, the number of flow tables supported by the SR, and the number of SNs supported by the SR.

Preferably, the selection submodule is specifically configured to select the identifiers of all SNs included in the SN list; or, if the SR attribute information includes the number of SNs supported by the SR, selecting an identifier of an SN from the SN list according to the number of SNs supported by the SR.

Preferably, the sending module 203 is specifically configured to call a function for reading information from a preset function library; and storing the topology configuration information in a management component on the network device through the function, wherein the management component comprises an open interface, and the open interface is used for transmitting the topology configuration information stored in the management component to the service chain control system after being called by the service chain control system.

In the embodiment of the present invention, the network device may be a server.

In the embodiment of the invention, SR attribute information sent by an SR is received, and topology configuration information is obtained, wherein the topology configuration information comprises the SR attribute information and an identifier of an SN attached to the SR; and sending the topology configuration information to a service chain control system, so that the service chain control system generates a service chain network topology according to the topology configuration information. Through the processing mode, the service chain control system can automatically acquire the topology configuration information and generate the service chain network topology according to the topology configuration information. Thus, the efficiency of generating the servicechain network topology is improved. In addition, the LLDP message can be extended to carry SR attribute information, so that the SR can report the SR attribute information to the network device through the LLDP message.

Referring to fig. 3, an embodiment of the present invention provides a method for sending information, where a processing flow of the method may include the following steps:

step 301, receiving SR attribute information sent by an SR, where the SR attribute information at least includes an identifier of the SR;

step 302, acquiring topology configuration information, where the topology configuration information includes the SR attribute information and an identifier of an SN included in a network device;

step 303, sending the topology configuration information to the service chain control system.

In the embodiment of the present invention, the network device may be a server.

Alternatively, the various steps shown in fig. 3 may be performed by the network device shown in fig. 2.

In the embodiment of the invention, SR attribute information sent by an SR is received, wherein the SR attribute information at least comprises an identifier of the SR; acquiring topology configuration information, wherein the topology configuration information comprises the SR attribute information and an identifier of an SN (service number) included by a network device; and sending the topology configuration information to a service chain control system, and generating a Servicechain network topology by the service chain control system according to the topology configuration information. Through the processing mode, the service chain control system can automatically acquire the topology configuration information and generate the Servicechain network topology according to the topology configuration information. Thus, the efficiency of generating the servicechain network topology is improved.

Referring to fig. 4-1, an embodiment of the present invention provides a method for sending information, including:

step 401, the SR sends SR attribute information to the server connected to it, where the SR attribute information at least includes an identifier of the SR;

the SR may be directly connected to the server, that is, there is no other device on the link between the SR and the server, and the SR may also be connected to the server through another device, for example, the SR may be connected to the server through a router. The identification of the SR may include an ID of the SR, a UUID of the SR, and/or a management IP address of the SR, etc. The SR attribute information may further include an interface type of the SR, an interface number of the SR, the number of flow tables supported by the SR, and/or the number of SNs supported by the SR.

The SR may send the SR attribute information to the server through the LLDP message, specifically:

and the SR selects a bit from reserved bits in a system capability field of the LLDP message, sets the bit, sets the data unit of the LLDP message to carry SR attribute information, and sends the LLDP message to a server directly connected with the data unit of the LLDP message, wherein the set bit is used for indicating that the data unit of the LLDP message carries SR attribute information.

Referring to fig. 4-2, the LLDP message includes DA, SA, Type, FCS, and data unit. The DA is used for carrying a destination MAC address, and for the LLDP message, the destination MAC address is 01-80-C2-00-00-0E. The SA is used to carry the source MAC address. The Type is used for carrying the message Type, and for the LLDP message, the message Type carried by the Type is 0x88 CC. The FCS is used to carry a frame check sequence. The data unit is an information exchange main body of the LLDP message, and may carry different information, and in the embodiment of the present invention, the data unit carries SR attribute information.

The data unit includes a system capability TLV and at least one system attribute TLV. The system capability TLV precedes the system attribute TLV in the data unit. The system capability TLV comprises a system capability field, bits in the system capability field represent a system capability, and the system attribute TLV is used for carrying information.

Referring to the system capability TLV shown in fig. 4-3, the system capability TLV includes a TLV type field (TLVType), a capability/status character length field (Capabilities/statusstrusinglength), a system capability field (SystemCapabilities), and an enabled capability field (enablecacapabilities). The system capability field includes two bytes, i.e., 16 bits. Each system capability of the data unit corresponds to a bit in the system capability field, and if a certain specific feature is set, the system capability TLV is used to indicate that the data unit has the system capability corresponding to the bit.

For example, referring to table 1, table 1 shows each system capability and the corresponding bit of each system capability, such as the fifth row record of table 1, which indicates that the routing function corresponds to the fourth bit in the system capability field. The system capability TLV is used to specify the routing function that the data unit has if the fourth bit in the system capability field is set.

TABLE 1

Bit position	System capability
		1	Repeater
2	Bridge
		3	Access Point
4	Router
		5	Telephone
6	Wireless Station
		7	Station Only
8-16	Retention

It can be seen from table 1 that the eighth to sixteenth bits of the system capability field remain. Therefore, in the embodiment of the present invention, one bit can be selected from the reserved bits, and the system function corresponding to the bit is defined as an SR function. If the selected bit position is set, it indicates that the data unit has the SR function, and defines that the data unit having the SR function can carry SR attribute information.

Referring to the system attribute TLV shown in fig. 4-4, the system attribute TLV includes a TLV header and a payload portion, the TLV header is used to carry information types, and each value formed by the TLV field represents an information type. For example, referring to table 2, one type of information represented by each value formed by the TLV field, e.g., the type of information represented by value 5 formed by the TLV field is a device name. The payload part is used for carrying information corresponding to the information type.

TABLE 2

Correspondingly, the data unit configured to carry the SR attribute information in the LLDP packet may be:

and setting a TLV head contained in the system attribute TLV of the LLDP message to carry an information type corresponding to the SR attribute information, and setting a payload part contained in the system attribute TLV of the LLDP message to carry the SR attribute information so as to realize that a data unit of the LLDP message is set to carry the SR attribute information.

Step 402, a server receives SR attribute information sent by an SR;

specifically, the server receives an LLDP message sent by the SR, determines whether a reserved bit in a system capability field in the LLDP message is set, determines that the LLDP message carries SR attribute information if the reserved bit is set, and extracts the SR attribute information from a data unit of the LLDP message.

Step 403: the server obtains topology configuration information including SR attribute information and an identification of a SN included in itself.

Wherein, the server comprises at least one SN. There is a list of SNs in the server that stores an identification of the SNs that it itself includes. The identification of the SN may uniquely identify the SN in the servicechain network, and the SN identification may be, but is not limited to, an ID of the SN, a UUID of the SN, and/or a management IP address of the SN.

The step may be that the server selects an identifier of an SN from the SN list, establishes an attachment relationship between the SN and the SR according to the received SR attribute information and the selected identifier of the SN, where the attachment relationship between the SN and the SR includes the identifier of the SR and the selected identifier of the SN, and uses the attachment relationship table between the SN and the SR as the topology configuration information. The topology configuration information may further include any one or more of an interface type of the SR, an interface number of the SR, the number of flow tables supported by the SR, the number of SNs supported by the SR, and the like in the SR attribute information.

The identity of the SN may be selected from the list of SNs by two means, including:

firstly, selecting the identifications of all SNs included in the SN list;

secondly, if the SR attribute information comprises the SN number supported by the SR, selecting the SN mark from the SN list according to the SN number supported by the SR.

The server is provided with a virtual machine management module, and the virtual machine management module can receive SR attribute information sent by an SR and acquire and store topology configuration information.

Step 404, the server sends topology configuration information to the service chain control system;

the server includes a function library, and in the embodiment of the invention, a function for reading information is expanded in the function library. In addition, a management component is also arranged in the server, the management component is provided with an open interface, and the open interface is opened to the service chain control system. One implementation of the library of functions may be libvirt.

The method comprises the following steps: the server calls a function for reading information from a preset function library; the topology configuration information is deposited in its own management component, which includes an open interface, through a called function. The service chain control system calls an open interface of the management component and calls the topology configuration information from the management component through the open interface.

The server calls topology configuration information from the virtual machine management module through the called function, and then stores the called topology configuration information in the management component.

Step 405: and the service chain control system receives the topology configuration information and generates a service chain network topology according to the topology configuration information.

And the service chain control system determines each SR and the SN attached to each SR according to the topology configuration information, and generates a service chain network topology according to each SR and the SN attached to each SR. The resulting traffic chain network topology is shown in fig. 4-5, for example.

In the embodiment of the invention, SR attribute information sent by SR is sent to a server, the server acquires topology configuration information and then sends the topology configuration information to a service chain control system, and the service chain control system generates service chain network topology according to the topology configuration information. Through the processing mode, the service chain control system can automatically acquire the topology configuration information and generate the service chain network topology according to the topology configuration information. Thus, the efficiency of generating the servicechain network topology is improved.

Referring to fig. 5, an embodiment of the present invention provides a network device, which includes a memory 501, a processor 502 and one or more programs, wherein the one or more programs are stored in the memory 501, and configured to be executed by the processor 502 comprises instructions for:

The receiving of the SR attribute information sent by the service router SR includes:

and extracting SR attribute information from the data unit of the LLDP message.

The memory 501 is permanent (non-transient in english).

Preferably, the receiving a link layer discovery protocol LLDP packet carrying SR attribute information sent by the service router SR includes:

Preferably, the topology configuration information at least includes SN and SR attachment relationships;

the acquiring topology configuration information includes:

Preferably, the selecting the identifier of the SN from the SN list includes:

selecting the identifications of all SNs included in the SN list; or,

Preferably, the sending the topology configuration information to a service chain control system includes:

calling a function for reading information from a preset function library;

Preferably, the SR attribute information further includes any one or more of an interface type of the SR, an interface number of the SR, the number of flow tables supported by the SR, and the number of SNs supported by the SR.

The network device shown in fig. 5 may perform all operations performed by the server in the embodiments corresponding to the five figures of fig. 4-1 to 4-5 according to one or more programs.

In the embodiment of the invention, SR attribute information sent by an SR is received, wherein the SR attribute information at least comprises an identifier of the SR; acquiring topology configuration information, wherein the topology configuration information comprises the SR attribute information and an identifier of an SN attached to the SR; and sending the topology configuration information to a service chain control system, so that the service chain control system generates a service chain network topology according to the topology configuration information. Through the processing mode, the service chain control system can automatically acquire the topology configuration information and generate the service chain network topology according to the topology configuration information. Thus, the efficiency of generating the servicechain network topology is improved.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims

1. A network device, wherein the network device comprises:

an obtaining module, configured to obtain topology configuration information, where the topology configuration information includes the SR attribute information and an identifier of a service node SN included in the network device;

2. The network device of claim 1,

the receiving module is used for receiving a Link Layer Discovery Protocol (LLDP) message which is sent by a Service Router (SR) and carries SR attribute information, and extracting the SR attribute information from a data unit of the LLDP message.

3. The network apparatus of claim 2,

the receiving module is specifically configured to receive a link layer discovery protocol LLDP packet sent by a service router SR, determine that the LLDP packet carries SR attribute information if a reserved bit in a system capability field of the LLDP packet is set, and extract the SR attribute information from a data unit of the LLDP packet.

4. The network apparatus of claim 1, wherein the topology configuration information at least comprises SN and SR attachment relationships;

the acquisition module includes:

a selection submodule, configured to select an identifier of a SN from a SN list, where the SN list is used to store the identifier of the SN included in the network device;

5. The network device of claim 4,

the selection submodule is used for selecting the identifications of all SNs included in the SN list; or, if the SR attribute information includes the SN number supported by the SR, selecting an identifier of an SN from the SN list according to the SN number supported by the SR.

6. The network device of claim 1,

the sending module is specifically used for calling a function for reading information from a preset function library; and storing the topology configuration information in a management component on the network device through the function, wherein the management component comprises an open interface, and the open interface is used for transmitting the topology configuration information stored in the management component to the service chain control system after being called by the service chain control system.

7. The network device according to any of claims 1 to 6, wherein the SR attribute information further comprises any one or more of an interface type of the SR, an interface number of the SR, the number of flow tables supported by the SR, and the number of SNs supported by the SR.

8. A method for transmitting information, the method comprising:

9. The method according to claim 8, wherein the receiving the SR attribute information sent by the service router SR comprises:

and extracting SR attribute information from the data unit of the LLDP message.

10. The method of claim 9, wherein the receiving the link layer discovery protocol LLDP packet carrying SR attribute information sent by the service router SR comprises:

11. The method according to claim 8, wherein the topology configuration information at least comprises SN and SR attachment relation;

the acquiring topology configuration information includes:

12. The method of claim 11, wherein selecting the identity of the SN from the list of SNs comprises:

selecting the identifications of all SNs included in the SN list; or,

13. The method of claim 8, wherein the sending the topology configuration information to a service chaining control system comprises:

calling a function for reading information from a preset function library;

14. The method according to any of claims 8 to 13, wherein the SR attribute information further comprises any one or more of an interface type of the SR, an interface number of the SR, the number of flow tables supported by the SR, and the number of SNs supported by the SR.

15. A network device comprising a memory, a processor, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the processor the one or more programs include instructions for: