CN105991390B - A Method of Realizing Multi-homing Connection VPLS in DOCSIS/DPoE Network - Google Patents

Abstract

The present invention provides the method that the Virtual Private LAN Service for returning connection based on BGP are realized in a kind of provider edge router of DOCSIS/DPoE network more, including step: obtaining cable modem configuration files from the configuration server of backstage, wherein, the configuration file includes bgp attribute subtype length value；Believe modern parameter according to the bgp attribute subtype length value configuration BGP for returning connection more；Pseudo-wire is created and safeguards according to the BGP signaling parameters for returning connection, thus with establishing and safeguarding the Virtual Private LAN Service for returning connection based on BGP in network between other provider edge routers more more.Wherein, include: that BGP returns connection configuration subtype in the bgp attribute subtype length value more, be used to configure the special parameter item in BGP signaling parameter needed for realizing the Virtual Private LAN Service for returning connection based on BGP more.In addition, the invention also provides the methods for automatically configuring routing differentiation parameter and route target parameter.

Description

A Method of Realizing Multi-homing Connection VPLS in DOCSIS/DPoE Network

technical field

The present invention relates to the field of communication, in particular, the present invention relates to a method for realizing virtual private local area network service (VPLS) based on BGP multi-homing connection in an operator's edge router of a DOCSIS/DPoE network.

Background technique

Cable Lab (Cable TV Lab), DOCSIS (Cable Data Service Interface Specification) and DPoE (DOCSIS Configuration of EPON Specification) specifications support configuration on CMTS (Cable Modem Termination System) or DPoE system to support BGP-AD (border Gateway Protocol-Auto Discovery) LDP (Label Distribution Protocol) virtual private LAN service and BGP virtual private LAN service. In order to support these features, Wired Labs has defined the BGP Attribute Sub Type Length Value (BGP Attribute Sub TLV) (43.5.21) under the L2VPN Encoding TLV (43.5) to encode the Border Gateway Protocol signaling parameters required by RFC6074 or RFC4761 .

However, the current definition of the BGP attribute sub-TLV (43.5.21) only supports the deployment of VPLS services in its simplest form. In addition to the simplest models, the MSO (Multiple System Operator) market demands more flexible and reliable VPLS deployment models. For example, the IETF standard VPLS multi-homing solution is the most desirable deployment model in the business services market.

The present invention attempts to expand the existing standard DOCSIS/DPoE definition for the BGP attribute sub-TLV (43.5.21) to support the deployment of the virtual private local area network service solution based on IETF BGP multi-homing connection.

Contents of the invention

In order to realize the purpose of the present invention, the first aspect of the present invention provides a kind of method for realizing the virtual private local area network service based on the multi-homing connection of BGP in the edge router of the operator of a kind of DOCSIS/DPoE network, including step: from background configuration server Obtain the cable modem configuration file, wherein, the configuration file includes the BGP attribute subtype length value; configure the BGP signaling parameters of the multi-homing connection according to the BGP attribute subtype length value; according to the BGP signaling of the multi-homing connection Parameters create and maintain pseudowires, thereby establishing and maintaining virtual private LAN services based on BGP multi-homing connections with other carrier edge routers in the network.

In particular, the BGP attribute subtype length value includes: BGP multi-homing connection configuration subtype, which is used to configure specific parameter items in the BGP signaling parameters required for virtual private local area network services based on BGP multi-homing connections .

Specifically, the BGP multi-homed connection configuration subtype includes the following subtype length value: a multi-homed connection site identification subtype length value, which is used to configure the multi-homed connection site identification parameter to indicate the user edge device of the multi-homed connection logo.

In particular, the BGP multi-homed connection configuration subtype also includes at least one of the following multiple subtype length values: a route distinguishing subtype length value, which is used to configure route distinguishing parameters to distinguish different virtual private networks; route target Subtype length value, which is used to configure routing target parameters to identify different VFRs; priority subtype length value, which is used to configure multi-homing connection priority parameters to indicate that the carrier's edge router is designated in the multi-homing connection The priority of the forwarder.

In particular, the BGP attribute subtype length value also includes 5 standard subtypes, wherein the 5 standard subtypes are: BGP VPNID, standard route distinction, standard import route target, standard export route target and CE-ID/VE-ID.

In particular, the route distinguishing parameter and the route target parameter are generated based on the five standard subtype configurations.

In particular, the method for configuring the route distinguishing parameters includes the following steps: I. Confirm the configuration status of the BGP VPNID and the CE-ID/VE-ID, i. If both are configured or are not configured, then report an error ; ii. If only the BGPVPNID or the CE-ID/VE-ID is configured, then set the value of the route distinguishing parameter: RD type code, route identifier and concatenation of any number.

In particular, the route identifier is four 8-bit system IPv4 addresses of the CMTS or DPoE system.

In particular, the arbitrary number is a monotonically increasing integer greater than 1 and less than 65535.

In particular, the method for configuring the routing target parameters includes the following steps: I. Confirm the configuration status of the BGP VPNID and the CE-ID/VE-ID, i. If both are configured or are not configured, then report an error ; ii. If only the BGPVPNID is configured, then set the value of the routing target parameter: RT type code, ASN and the concatenation of the value of the BGP VPNID; iii. If only the CE-ID/VE -ID is configured, then judge whether the standard import routing target and the standard export routing target are configured and the same: if they have been configured and are the same, the value of the routing target parameter is the standard import routing target or the The value of the routing target is exported according to the above standard; otherwise, an error is reported.

Specifically, the ASN is two 8-digit autonomous system numbers of the CMTS or DPoE system.

In particular, the method for configuring the priority parameter of the multi-homing connection includes the following steps: converting the system address of the carrier edge router into a numerical value; and configuring the value of the priority parameter of the multi-homing connection as the converted numerical value.

The present invention proposes to define a new BGP multihoming connection configuration item conforming to DOCSIS to configure the VPLS multihoming connection scheme for CMTS or DPoE system stipulated in "draft-IETF-L2VPN-VPLS-multihoming". In addition, the present invention also proposes a method for automatically configuring route distinguishing parameters and route target parameters of BGP signaling for VPLS multi-homing connections.

Description of drawings

Other characteristics, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Fig. 1 shows a kind of DOCSIS/DPoE network schematic diagram of the VPLS that supports multi-homing connection disclosed according to the present invention;

Fig. 2 shows the flow chart of the method for realizing the virtual private local area network service based on BGP multi-homing connection in the edge router of the operator;

Fig. 3 shows the flow chart of the method for configuring routing distinction (RD) parameters according to the present invention; and

Fig. 4 shows a flowchart of a method for configuring routing target (RT) parameters disclosed in the present invention.

Detailed ways

In the following detailed description of the preferred embodiment, reference is made to the accompanying drawings which form a part hereof. The accompanying drawings show, by way of example, specific embodiments in which the invention can be practiced. The illustrated embodiments are not intended to be exhaustive of all embodiments in accordance with the invention. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. Accordingly, the following detailed description is not limiting, and the scope of the invention is defined by the appended claims. In addition, while the specification describes steps of a method in a particular order, this does not require or imply that operations must be performed in that particular order, or that all illustrated operations must be performed to achieve desirable results. Rather, the depicted Steps can change the order of execution. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step for execution, and/or one step may be decomposed into multiple steps for execution.

At present, the best VPLS multi-homing connection scheme is based on the extended BGP protocol, for example, it is defined in "Draft-IETF-L2VPN-VPLS-multihoming )" in the scheme. In the DOCSIS/DPoE specification, there is no standard type-length value that can be used to configure a CMTS or DPoE system to provide a multi-homing connection scheme that supports VPLS. Therefore, the configuration method proposed by the present invention is the first example.

FIG. 1 shows a schematic diagram of a DOCSIS/DPoE network deployment of VPLS supporting multi-homing connections disclosed in the present invention. Among them, BGP-MH means BGP multi-homing connection, BGP RR is BGP route reflector, MEF UNI is Metro Ethernet Forum user network interface, VPLS PE is provider edge device of virtual private area network service, VSI is virtual exchange instance, D -ONU is the optical network unit of DPoE, and CE is the user edge device of multi-homing connection.

In the existing single-connection network deployment, the customer edge equipment CE can only be connected to a VPLS service instance (Service Instance) through one communication path. For example, the CE is connected to the line of the VPLS service instance through D-OUN1 and the path on the side of CMTS/DPoE system 1, or the CE is connected to the line of the VPLS service instance through D-OUN2 and the path on the side of CMTS/DPoE system 2. In order to achieve communication reliability, VPLS multi-homing connections are applied to DOCSIS/DPoE networks, that is, CEs can be connected to VPLS service instances through two or more communication paths.

However, in the current DOCSIS/DPoE specification, the definition of the BGP attribute sub-TLV (43.5.21) cannot support the configuration of the BGP protocol for VPLS multihoming as specified in "draft-IETF-L2VPN-VPLS-multihoming" signaling information.

Currently, the laboratory has defined the BGP attribute sub-TLV (43.5.21) for LDP-VPLS and BGP-VPLS supporting BGP-AD according to RFC6074 and RFC4761. Under the BGP attribute sub-TLV (43.5.21), there are 5 standard subtypes that have been defined, which are: BGP VPNID (43.5.21.1), route differentiation (43.5.21.2), import route target (43.5.21.3 ), export route target (43.5.21.4), and CE-ID/VE-ID (43.5.21.5). Among them, route differentiation (43.5.21.2), route target (import) (43.5.21.3), route target (export) (43.5.21.4) are used to configure BGP parameters for LDP-VPLS and BGP-VPLS supporting BGP-AD ; BGP VPNID (43.5.21.1) is specially used to configure parameters for LDP-VPLS supporting BGP-AD; CE-ID/VE-ID (43.5.21.5) is specially used to configure parameters for BGP-VPLS.

Wherein, in order to distinguish it from the routing distinction (43.5.21.6.1) below, in this paper, the routing distinction (43.5.21.2) is called a standard routing distinction. Likewise, the import routing target (43.5.21.3) and the export routing target (43.5.21.4) are referred to herein as the standard import routing target (43.5.21.3) and the standard export routing target (43.5.21.4).

It should be pointed out that: CE-ID/VE-ID (43.5.21.5) can also be used to configure parameters for BGP-VPWS (Border Gateway Protocol-Virtual Personal Wire Service) based on RFC6624. However, since VPWS services are out of the scope of the present invention, they will not be mentioned in this text.

In order to provide VPLS with multi-homing connections based on the BGP protocol, the present invention proposes to define a new subtype: BGP multi-homing connection configuration, so that it can configure the necessary BGP signaling parameters required by the VPLS multi-homing connection scheme.

The BGP multi-homed connection configuration subtype can be placed anywhere under the BGP attribute sub-TLV (43.5.21). In order to simplify the description in this specification, the newly established BGP multi-homing connection configuration subtype is numbered 43.5.21.6, which is arranged after other subtype length values (TLVs) defined in the BGP attribute sub-TLV (43.5.21). It should be pointed out that: the subtype number of the BGP multi-homing connection configuration object used in the present invention is only for the purpose of illustration, and the use of other numbers will not affect its function. The final number of the subtype can only be determined and publicly used after the formal agreement of the cable laboratory. Below we introduce the BGP multi-homing connection configuration subtype (43.5.21.6) in detail:

BGP Multi-homing Configuration (BGP Multi-homing Configuration)

Subtype: 43.5.21.6

Length: n (natural number)

Value: The value of a BGP multihomed connection configuration is the composite value of its subtype/length/value tuples.

The BGP multi-homing connection configuration subtype is multi-part encoding, which is used to configure the required parameters of the BGP multi-homing connection scheme. The BGP multi-homing connection configuration subtype includes the following multiple subtype length values (subTLV):

1. Route Distinguisher

Subtype: 43.5.21.6.1

Length: 8

Value: integer

The route distinguishing subtype length value (RD sub TLV) is used to configure the route distinguishing (RD) parameter in the NLRI (Network Layer Reachability Information) field in the BGP update information of the multi-homing connection signaling. The route distinguishing parameter is mainly used to distinguish different virtual private networks, and the specific usage and format are defined in RFC4364, which will not be repeated here. The route distinguishing subtype length value is an optional subtype length value in the BGP multihoming connection configuration subtype. If the operator does not configure the subtype length value in the BGP multi-homing connection configuration subtype, the CMTS or DPoE system must automatically configure a value for the route distinguishing parameter.

2. Route Target

Subtype: 43.5.21.6.2

Value: integer

The routing target subtype length value (RT sub TLV) is used to configure the routing target (RT) parameter of the extended common attribute of the BGP update information of the multi-homing connection signaling. The routing target parameter is mainly used to identify different virtual routing and forwarding tables (VFRs). The purpose and format of specific routing target parameters are defined in RFC4364, which will not be repeated here. For BGP multi-homing connection signaling, the exported routing target must be consistent with the imported routing target, so only one routing target subtype length value is sufficient. The route target subtype length value is an optional subtype length value in the BGP multihoming connection configuration subtype. If the operator does not configure the subtype length value in the BGP multi-homing connection configuration subtype, the CMTS or DPoE system must automatically configure a value for the routing target parameter.

It should be pointed out that: BGP-AD, BGP-VPLS, and BGP multi-homing connection schemes use different types of BGP update information, and the route distinguishing parameter and the value of the route distinguishing parameter may be different among them. Therefore, the BGP multihoming connection configuration subtype must have its own configuration for route distinction and route destination, which is different from the existing standard route distinction (43.5.21.2), standard import route destination (43.5.21.3), standard export The route target (43.5.21.4) is different. When the way of choosing the value of route distinguishing and route distinguishing parameters is properly specified, they can be configured automatically even if they are not configured manually. Inappropriate manually configured route distinction and route target parameter values may cause failures in the BGP multi-homing connection scheme. Therefore, in most cases, it is recommended that the operator does not set the value of the route distinction and route target subtype length, and the CMTS or DPoE system automatically configures a value for the route distinction and/or route target parameters.

3. Multi-homed Site ID

Subtype: 43.5.21.6.3

Length: 2

Value: Unsigned natural number from 1 to 65535

The multi-homed site ID subtype length value (Multi-homed site ID sub TLV) is used to encode the site ID (such as the CE ID in Figure 1) parameter of the multi-homed site. The usage of the Multihoming Connection Site Identifier is defined in "draft-IETF-L2VPN-VPLS-multihoming". The subtype length value of the multi-homing connection site identifier is a mandatory subtype length value of the BGP multi-homing connection configuration subtype, that is to say, each BGP multi-homing connection configuration subtype must have a multi-homing connection site identifier subtype length value.

4. Priority (Preference)

Subtype: 43.5.21.6.4

Length: 2

Value: Unsigned natural number from 1 to 65535

Preference sub-type length value (Preference sub TLV), which is used to configure the priority parameters of the multi-homing connection, so as to indicate the priority of the operator's edge router as the designated forwarder in the multi-homing connection. VPLS edge devices with higher priority will have more chances to be selected as designated forwarding routers. The priority subtype length value is an optional subtype length value in the BGP multi-homing connection configuration subtype.

In the following, we will explain how to use the above-mentioned extended BGP attribute subtype length value to configure the BGP signaling parameters of the multi-homing connection VPLS, so as to realize the virtual private local area network service based on the BGP multi-homing connection.

Fig. 2 shows a method for implementing virtual private local area network services based on BGP multi-homing connections in an operator's edge router.

In step 202, the operator's edge router acquires a cable modem (CM) configuration file from a background configuration server (TFTP), wherein the configuration file includes a BGP attribute subtype length value.

In step 204, the provider's edge router (PE) configures the BGP signaling parameters of the multi-homing connection according to the BGP attribute subtype length value (BGPAttribute Sub TLV). Wherein, the BGP attribute subtype length value includes: BGP multi-homing connection configuration sub-type, which is used to configure specific BGP signaling parameters required for virtual private local area network services (VPLS) based on BGP multi-homing connections. parameter item. The specific parameter items include: a route distinction parameter, a route target parameter, a multi-homing connection priority parameter, and a multi-homing connection site identification parameter.

The BGP multi-homed connection configuration subtype includes a multi-homed connection site identification subtype length value, which is used to configure the multi-homed connection site identification parameter to indicate the identification of the customer edge equipment (CE) of the multi-homed connection. In addition, the BGP multi-homing connection configuration subtype can also include the following optional subtype length values:

Route distinguishing subtype length value, which is used to configure route distinguishing parameters to distinguish different virtual private networks.

Route target subtype length value, which is used to configure route target parameters to identify different VFRs.

Priority subtype length value, which is used to configure the multi-homing connection priority parameter, to indicate the priority of the carrier's edge router as the designated forwarder in the multi-homing connection.

When missing these optional subtype length values in the BGP multi-homing connection configuration subtype, the present invention implements configuration to route distinguishing parameter, routing target parameter and multi-homing connection priority parameter through the following steps:

1. The method of configuring route distinguishing parameters:

In the BGP update message used for multi-homed connection signaling, the value of the route distinguishing (RD) parameter itself has no meaning, what really matters is that the value of the route distinguishing parameter must be unique for each multi-homed connected site. Its purpose is to ensure that BGP update information from different multi-homed connection sites will not be incorrectly regarded as multiple redundant identical routes by intermediate BGP nodes (such as BGP route reflectors). The CMTS or DPoE system may use any method to generate the parameter value of the unique route distinguishing parameter. For example, the value of the route distinguishing parameter can be composed of 3 fields, the first field is 2 8-bit numbers, which can be set to 0x0001 (type of route distinction); the second field is 4 8-bit numbers, It can be set as the routing identifier (system address) of the CMTS or DPoE system; the third field is any number between 2 8-bit numbers 1-65535.

In a specific embodiment, the route distinguishing parameter and route target parameter can be generated based on five subtype configurations of BGP VPNID, standard route distinguishing, standard imported route target, standard exported route target and CE-ID/VE-ID. Fig. 3 shows a flow chart of a method for configuring route distinction (RD) parameters disclosed in the present invention.

In step 302, the operator edge router confirms the configuration status of BGP VPNID and CE-ID/VE-ID in the BGP attribute subtype length value, to confirm whether only BGP VPNID or CE-ID/VE-ID is configured. If BGP VPNID or CE-ID/VE-ID are all configured or not configured, then implement step 304 and report an error to indicate that the automatic configuration fails; if only the BGP VPNID or the CE-ID/VE-ID are configured, Then implement step 306 to set the value of the route distinguishing parameter: route distinguishing type code (Type_Code_RD), route identification (Route_ID) and the concatenation of any number. Wherein, the route identification (Route_ID) is 4 8-bit system IPv4 addresses of the CMTS or DPoE system; the arbitrary number is a monotonically increasing integer greater than 1 and less than 65535 (that is, each selected number must be greater than the previous one) selected number).

2. How to configure routing target parameters:

In the BGP update message used for multi-homing connection signaling, the value of the import route target and the export route target must be the same, so we can use 1 parameter route target to encode both. The routing target can be the encoding of the VPLS ID. For LDP-VPLS supporting BGP-AD, the VPLS ID is directly encoded with the existing BGP VPN ID (43.5.21.1) per DOCSIS/DPoE specification. For BGP-VPLS, the VPLS ID is implicitly encoded with the standard import route target (43.5.21.3) and standard export route target (43.5.21.4) of each RFC4761 (both values must be the same in each RFC4761). Therefore, for any case of LDP-VPLS or BGP-VPLS supporting BGP-AD, the routing target (43.5.21.6.2) value of the BGP multi-homing connection signaling can be automatically configured and generated.

In a specific embodiment, the route distinguishing parameter and route target parameter can be generated based on five subtype configurations of BGP VPNID, standard route distinguishing, standard imported route target, standard exported route target and CE-ID/VE-ID.

Fig. 4 shows a flowchart of a method for configuring routing target (RT) parameters disclosed in the present invention. In step 402, the operator's edge router confirms the configuration status of BGP VPNID and CE-ID/VE-ID in the BGP attribute subtype length value, to confirm whether BGP VPNID and CE-ID/VE-ID are all configured or not Configuration, if all are configured or none are configured, an error is reported in step 404 to indicate that the automatic configuration fails. Otherwise, it is confirmed in 406 whether only BGP VPNID is configured. If only BGP VPNID is configured, set the value of the route target parameter in step 408: the concatenation of RT type code (Type_Code_RT), ASN and BGP VPNID. If only CE-ID/VE-ID is configured, then in step 410 it is judged whether the standard import route target (43.5.21.3) and the standard export route target (43.5.21.4) are configured and the configured values of the two are the same, if The standard import routing target (43.5.21.3) and the standard export routing target (43.5.21.4) are configured and have the same value, then in step 412, the value of the routing target parameter is the standard import routing target or the standard export routing target value. Otherwise, step 414 is implemented to report an error indicating that the automatic configuration fails.

3. How to configure priority parameters:

The priority of a VPLS provider edge router (PE) selected as a designated forwarding router will be determined by the value of the PE's system address. A VPLS provider edge router with a smaller system address value will have a higher priority than a VPLS provider edge router with a larger system address value.

Specifically, the system address of the carrier's edge router may be converted into a value first; and then the value of the multi-homing connection priority parameter may be set as the converted value of the system address of the carrier's edge router.

After configuring the BGP signaling parameters of the above-mentioned multi-homing connection, step 206 is implemented: the operator edge router creates and maintains a pseudowire according to the configured BGP signaling parameters of the multi-homing connection VPLS, thereby communicating with other Establish and maintain virtual private local area network services based on BGP multi-homing connections between carrier edge routers (PEs).

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all respects as exemplary and not restrictive. Furthermore, it is obvious that the word "comprising" does not exclude other elements and steps, and the word "a" does not exclude the plural. A plurality of elements recited in device claims may also be embodied by one element. The words first, second, etc. are used to denote names and do not imply any particular order.

Claims (11)

1. the method for realizing the virtual private local area network business based on the multi-homing connection of BGP in the operator's edge router of a kind of DOCSIS/DPoE network, comprising steps: Obtain the cable modem configuration file from the background configuration server, wherein the configuration file includes a BGP attribute subtype length value, and the BGP attribute subtype length value includes: BGP multi-homing connection configuration subtype, which is used for configuration implementation Specific parameter items in the BGP signaling parameters required by the virtual private local area network service based on BGP multi-homing connection; Configure the BGP signaling parameters of the multi-homing connection according to the BGP attribute subtype length value; Create and maintain a pseudowire according to the BGP signaling parameters of the multi-homing connection, so as to establish and maintain virtual private local area network services based on the BGP multi-homing connection with other operator edge routers in the network. 2. The method according to claim 1, wherein the BGP multi-homed connection configuration subtype comprises the following subtype length values: Multi-homing connection site identification subtype length value, which is used to configure the multi-homing connection site identification parameter to indicate the identification of the user edge device of the multi-homing connection. 3. The method according to claim 2, wherein the BGP multi-homed connection configuration subtype further comprises at least one of the following multiple subtype length values: Route distinguishing subtype length value, which is used to configure route distinguishing parameters to distinguish different virtual private networks; Routing target subtype length value, which is used to configure routing target parameters to identify different VFRs; The priority subtype length value is used to configure the multi-homing connection priority parameter to indicate the priority of the carrier edge router as a designated forwarder in the multi-homing connection. 4. The method according to claim 2, wherein the BGP attribute subtype length value also includes 5 standard subtypes, wherein the 5 standard subtypes are respectively: BGP VPNID, standard route distinction, Standard Import Routing Target, Standard Export Routing Target and CE-ID/VE-ID. 5. The method according to claim 4, wherein the route distinguishing parameter and the route target parameter are generated based on the five standard subtype configurations. 6. The method according to claim 5, wherein the method for configuring the route distinguishing parameters comprises the following steps: I. confirm the configuration state of described BGP VPNID and described CE-ID/VE-ID, i. If both are configured or none are configured, an error will be reported; ii. If only the BGP VPNID or the CE-ID/VE-ID is configured, then set the value of the route distinguishing parameter: RD type code, route identifier and any number of concatenations. 7. The method according to claim 6, wherein the routing identifier is four 8-bit system IPv4 addresses of the CMTS or DPoE system. 8. The method according to claim 6, wherein the arbitrary number is a monotonically increasing integer greater than 1 and less than 65535. 9. The method according to claim 5, wherein the method for configuring the routing target parameters comprises the steps of: I. confirm the configuration state of described BGP VPNID and described CE-ID/VE-ID, i. If both are configured or none are configured, an error will be reported; ii. If only the BGP VPNID is configured, then set the value of the routing target parameter: the concatenation of RT type code, ASN and the value of the BGP VPNID; iii. If only the CE-ID/VE-ID is configured, then determine whether the standard import routing target and the standard export routing target are configured and the same: if configured and the same, the routing target parameter The value of is the value of the standard import route target or the value of the standard export route target; otherwise, an error is reported. 10. The method according to claim 9, wherein the ASN is two 8-bit autonomous system numbers of a CMTS or DPoE system. 11. The method according to claim 5, wherein the method for configuring multi-homing connection priority parameters comprises the following steps: converting the system address of the carrier edge router into a value; Configure the value of the multi-homing connection priority parameter as the converted value.