CN100527683C

CN100527683C - Failure protecting method and system

Info

Publication number: CN100527683C
Application number: CNB200610109933XA
Authority: CN
Inventors: 张志峰; 秦超
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2006-08-24
Filing date: 2006-08-24
Publication date: 2009-08-12
Anticipated expiration: 2026-08-24
Also published as: CN101132304A

Abstract

This invention discloses a fault protection method including: presetting two or more than two standby PE nodes for a flow downstream PE node, when a flow upstream PE node tests that it is impossible to reach the downstream PE node, it selects one from all the standby nodes in the downstream PE nodes to send messages to the client end under the main PE node via the standby one, at the same time, this invention also discloses a fault protection system including: a standby PE node configuring module, a main-standby PE node information storing module and a standby PE noide selection module.

Description

Fault protecting method and system

Technical field

The present invention relates to data communication technology field, be specifically related to a kind of fault protecting method and system.

Background technology

At present, based on the VPN(Virtual Private Network) technology of multiprotocol label switching (mpls), the business support ability with its good autgmentability and the formula of differentiation has obtained extensive use.In order to improve service reliability, local link, node are carried out the quick heavy-route of MPLS (FRR) technology of error protection, the PE node is carried out the VPN FRR technology of error protection and arise at the historic moment.

Fig. 1 is for carrying out the schematic diagram of error protection based on VPN FRR technology, as shown in Figure 1, PE1 is flow upstream Provider Edge (PE) node, and PE2 and PE3 are flow downstream PE node, and P1, P2, P3, P4 are router, and CE is the client under the PE2.When network design, be standby PE node of each flow downstream PE node configuration, as: the standby PE node that PE3 is configured to PE2, PE2 is called the main PE node of using, to lead simultaneously with the client CE under the PE node PE2 and directly link to each other with standby PE node PE3, then PE1-P1-P2-PE2-CE is the primary path between PE1 and CE, PE1-P4-P3-PE3-CE is the backup path between PE1 and CE, PE1 preserves this two paths information, when PE1 detects that primary path is unreachable or main to break down with PE node PE2, by standby PE node PE3 flow is mail to CE along backup path.

The shortcoming of carrying out error protection based on VPN FRR technology is:

One, each master has only a fixing standby PE node with the PE node, when the master is unreachable with the PE node, all mail to main flow with the client under the PE node by primary path all changes and is added on the backup path, can cause the flow on the backup path to increase suddenly, if there has been big flow on the backup path, the flow that then causes probably preparing to mail on the primary path can't all be loaded on the backup path, and cause preparing to mail to traffic loss on the primary path, also may cause losing of backup path self flow simultaneously.

Two, client is necessary for dual-homed topological structure, and promptly the master must directly be connected with standby PE node with the client under the PE node simultaneously, causes waste of network resources.

Summary of the invention

The invention provides a kind of fault protecting method and system, to avoid traffic loss.

Technical scheme of the present invention is achieved in that

A kind of fault protecting method for flow downstream PE node is provided with two or more standby PE nodes, comprising:

Flow upstream PE node detection is main unreachable with the PE node to the flow downstream, selects a standby PE node in all standby PE nodes of this flow downstream PE node, message is sent to main with the client under the PE node by this standby PE node.

Also comprise: for described each standby PE node is provided with a weight that is used to indicate by the flow on the backup path of this standby PE node correspondence;

Described flow upstream PE node selects a standby PE node to comprise in all standby PE nodes of flow downstream PE node:

Described flow upstream PE node is selected a standby PE node according to the weighted value of described each standby PE node.

Described flow upstream PE node detection is main to the flow downstream further to be comprised with the PE node is unreachable before:

Client terminal start-up under the described flow downstream PE node, to the standby PE node of described flow downstream PE node and the VPN routing iinformation of flow upstream PE node transmission self, standby PE node is with the VPN route network segment/mask information of this VPN routing iinformation correspondence, and VPN exchanging visit control information, the weighted value of self sends to flow upstream PE node, flow upstream PE node is according to VPN exchanging visit control information and the VPN route network segment/mask information, judge whether to accept the standby PE node of this standby PE node as described flow downstream PE node, if, flow upstream PE node generates the standby forwarding-table item of this standby PE node, and determines the priority of this standby PE node according to the weighted value of this standby PE node;

And, described flow upstream PE node sends to the master by this standby PE node with message and comprises with the client under the PE node: flow upstream PE node sends to this message main with the client under the PE node according to the standby forwarding-table item of this standby PE node correspondence by this standby PE node.

Client under the described flow downstream PE node further comprises after the VPN routing iinformation of the standby PE node transmission self of flow downstream PE node: standby PE node sends to flow upstream PE node with the next-hop address information of self, whether flow upstream PE node is identical with the main PE address of node information of using according to this next-hop address information, and preset rule, determine whether to accept this standby PE node.

Standby PE node sends to flow upstream PE node with the VPN route network segment/mask information, VPN exchanging visit control information, self weighted value: send to flow upstream PE node in the label distribution related protocol message by the VPN route network segment/mask information, VPN exchanging visit control information, self weighted value are carried at.

Described label distribution related protocol is: the tag distribution protocol (CR-LDP) of tag distribution protocol (LDP) or route restriction or at the expansion of the RSVP of traffic engineering (RSVP-TE) or multi-protocols border gateway protocol (MP-BGP).

All clients under the flow downstream PE node are distributed to each standby PE node of this flow downstream PE node respectively, the corresponding relation of record client-side information and standby PE nodal information;

Flow upstream PE node is determined main standby PE node with the client correspondence under the PE node according to described corresponding relation, with the standby PE node of this standby PE node as selection.

Client terminal start-up under the flow downstream PE node, to the standby PE node of flow downstream PE node and the VPN routing iinformation of flow upstream PE node transmission self, flow upstream PE node is preserved this VPN routing iinformation, standby PE node is with the VPN route network segment/mask information of this VPN routing iinformation correspondence, and VPN exchanging visit control information sends to flow upstream PE node, flow upstream PE node is according to VPN exchanging visit control information and the VPN route network segment/mask information, judge whether to accept this standby PE node, if flow upstream PE node generates the standby forwarding-table item of standby PE node;

A kind of fault recovery system comprises: standby PE node configuration module, active and standby PE nodal information preserve module and standby PE node is selected module, wherein:

Standby PE node configuration module is used to the two or more standby PE nodes of flow downstream PE node configuration, main corresponding relation with PE node and standby PE node is sent to active and standby PE nodal information preserve module;

Active and standby PE nodal information is preserved module, the next-hop address information of the main VPN route network segment/mask information with the client under the PE node that is used for sending according to standby PE node, VPN routing tag information, standby PE node generates the standby forwarding-table item of standby PE node, request according to standby PE node selection module sends to standby PE node with standby forwarding-table item and selects module;

Standby PE node is selected module, be used for detect main with the PE node when unreachable, select a standby PE node, according to preserve from active and standby PE nodal information the module request to the standby forwarding-table item of this standby PE node message is mail to client under the main usefulness PE node.

Described active and standby PE nodal information is preserved module and is further used for, indicate the weighted value of flow of the backup path of this standby PE node correspondence according to standby PE node being used to of sending, determine the priority of this standby PE node, according to request, the precedence information of this standby PE node is sent to standby PE node select module;

Described standby PE node selects module to be further used for, preserve the precedence information of the standby PE node of module request to active and standby PE nodal information, according to the standby PE address of node information and the precedence information of asking, select the highest standby PE node of priority, and preserve the standby forwarding-table item of this standby PE node correspondence of module request to active and standby PE nodal information.

Described standby PE node configuration module is further used for, and the client under the PE node is distributed to each standby PE node respectively, the corresponding relation of client address information and standby PE node address information is sent to active and standby PE nodal information preserve module;

Described active and standby PE nodal information is preserved module and is further used for, and according to request, the standby PE nodal information corresponding with this client address information is sent to standby PE node selection module;

Described standby PE node selects module to be further used for, preserve the module request to standby PE node address information according to client address information to active and standby PE nodal information, and preserve the standby forwarding-table item of this standby PE node correspondence of module request to active and standby PE nodal information.

Compared with prior art, the present invention is by for the two or more standby PE nodes of flow downstream PE node configuration, with the PE node when unreachable, selects a less backup path of flow to be carried on flow on the primary path when main; Perhaps,, select a backup path to be carried on flow on the primary path, avoided losing of the excessive flow that causes of the flow on the backup path according to preset rule; Simultaneously, the master does not require and must directly link to each other with standby PE node with the client under the PE node, has saved Internet resources.

Description of drawings

Fig. 1 is the existing schematic diagram that carries out error protection based on VPN FRR technology;

The flow chart that carries out error protection that Fig. 2 provides for the embodiment of the invention one;

Fig. 3 carries out the flow chart of error protection for what the embodiment of the invention two provided based on VPN FRR technology;

Fig. 4 forms schematic diagram for the system that carries out error protection that the embodiment of the invention provides;

The schematic diagram that carries out error protection that Fig. 5 provides for the embodiment of the invention one.

Embodiment

Core concept of the present invention is: be the two or more standby PE nodes of flow downstream PE node configuration, with the PE node when unreachable, can select a less backup path of flow to be carried on flow on the primary path when main; Perhaps, according to preset rule, select a backup path to be carried on flow on the primary path, for example: can in advance the flow of leading with all clients under the PE node be distributed to different backup paths respectively.

The present invention is further described in more detail below in conjunction with drawings and the specific embodiments.

Fig. 2 is the flow chart that carries out fault recovery that the embodiment of the invention one provides, in the present embodiment, obtain the flow information of each backup path in advance by statistics, when the master is unreachable with the PE node, can select the backup path of a flow minimum to be carried on flow on the primary path, as shown in Figure 2, its concrete steps are as follows:

Step 201: be the two or more standby PE nodes of flow downstream PE node configuration in advance, the flow upstream PE node of flow downstream PE node is preserved this flow downstream PE node promptly: main corresponding relation with PE address of node information and standby PE address of node information.

The concrete standby PE node of selecting which node as certain PE node can be disposed by the network manager when network design.

Main can directly be connected with standby PE node, also can directly not be connected and be connected indirectly with standby PE node with the PE node by leading with standby PE node with the client under the PE node.

Step 202: main with the client terminal start-up under the PE node, to this main VPN routing iinformation that sends self with the standby PE node and the flow upstream PE node of PE node.

Comprise VPN route network segment information etc. in the VPN routing iinformation.

Main with preserving flow upstream PE address of node information and the standby PE address of node information of this master on the client under the PE node with the PE node.

Step 203: flow upstream PE node is preserved this VPN routing iinformation after receiving the VPN routing iinformation that client sends.

Step 204: after standby PE node is received the VPN routing iinformation that client sends, the VPN route network segment/mask information of this VPN routing iinformation correspondence and VPN exchanging visit control information, the next-hop address information of self, the LSR sign (LSR-ID) of self, self weighted value etc. are carried in the summary info field of label distribution related protocol message, the VPN routing tag of this VPN routing iinformation correspondence are carried at send to flow upstream PE node in the label distribution related protocol message simultaneously.

Dispose flow upstream PE address of node information on the standby PE node.

The label distribution related protocol can be the tag distribution protocol (CR-LDP) of tag distribution protocol (LDP) or route restriction or at the RSVP expansion (RSVP-TE) of traffic engineering expansion or multi-protocols border gateway protocol (MP-BGP) etc.

Weighted value can obtain by the flow by backup path in statistics a period of time, and big more by the flow of backup path, weighted value is more little; Weighted value can periodically upgrade.

If main directly be connected with standby PE node with the client under the PE node, then standby PE node can oneself be VPN routing tag of this VPN routing iinformation distribution after receiving the VPN routing iinformation that client sends; If the client under the main PE of the using node does not directly link to each other with standby PE node but passes through the master and links to each other with standby PE node with the PE node, then the master when system initialization, sends to standby PE node with the VPN routing iinformation of this client and the VPN routing tag of correspondence with the PE node.

Step 205: after flow upstream PE node is received label distribution related protocol message,, judge whether to accept this standby PE node according to the VPN exchanging visit control information that this message is carried, if, execution in step 206; Otherwise, execution in step 208.

VPN exchanging visit control information can be a route target (RT) etc., and flow upstream PE node is by judging that whether the RT that self preserves and the RT in the VPN exchanging visit control information mate, and determine whether to accept this message.

Step 206: flow upstream PE node judges whether to find the VPN route network segment information that this message is carried in the VPN route network segment information of the VPN routing iinformation that all clients of self preserving are sent, if, execution in step 207; Otherwise, execution in step 208.

Step 207: whether the next-hop address information that flow upstream PE node carries according to this message uses PE address of node information identical with corresponding the leading of this standby PE node of self preserving, and the decision rule of self preserving, determine whether to accept this standby PE node, if, execution in step 209; Otherwise, execution in step 208.

Next-hop address information in this step can be LSR-ID etc., flow upstream PE node self preserve main with PE address of node information as: LSR-ID and standby PE address of node information as: in the corresponding relation of LSR-ID, search the main LSR-ID of the LSR-ID correspondence of the standby PE node that this label distribution related protocol message carries with the PE node, judge then described next whether jump LSR-ID identical with the LSR-ID of the main PE of using node.

Decision rule in this step refers to, and when the next-hop address information of the predefined standby PE node of flow upstream PE node uses PE address of node information identical with the master, accepts still to abandon the rule of this standby PE node.

Step 208: flow upstream PE node is abandoned this standby PE node, and in the main corresponding relation of self preserving with PE node address information and standby PE node address information, deletes this standby PE address of node information, goes to step 211.

Step 209: flow upstream PE node generates standby forwarding-table item according to this message, and this standby forwarding-table item comprises: the next-hop address information of the VPN route network segment/mask information, VPN routing tag information, standby PE node etc.

Step 210: flow upstream PE node is determined the priority of this standby PE node according to the weighted value of standby PE node, and preserves the precedence information of this standby PE node.

Flow upstream PE node can preestablish the corresponding relation of weighted value and priority, according to this corresponding relation, determines the weighted value corresponding priorities of standby PE node.

Step 211: flow upstream PE node is prepared to send message to main with the PE node, detect main unreachable with the PE node, the main corresponding relation of preserving according to self with PE address of node information and standby PE address of node information is searched the standby PE node of this master with PE node correspondence.

Step 212: flow upstream PE node is selected the highest standby PE node of priority according to the precedence information of each standby PE node of self preserving in the standby PE node that finds.

Step 213: flow upstream PE node is searched the standby forwarding-table item of this standby PE node correspondence in the fib table item, transmits this message according to this standby forwarding-table item that finds.

Flow upstream PE node is after receiving the label distribution related protocol message that standby PE node is sent, preserve the next-hop address information that this message carries and the corresponding relation of standby PE address of node information, in this step, flow upstream PE node can find the standby forwarding-table item of standby PE node correspondence according to this next-hop address information.

Fig. 3 is the flow chart that carries out fault recovery that the embodiment of the invention two provides, in the present embodiment, distribute to different standby PE nodes with main with all clients under the PE node, when the master is unreachable with the PE node, according to the standby PE node under the client, flow on the primary path is carried on the corresponding backup path, and as shown in Figure 3, its concrete steps are as follows:

Step 301: be the two or more standby PE nodes of flow downstream PE node configuration in the network in advance, and will lead with all clients under the PE node and distribute to each standby PE node respectively, this master preserves main corresponding relation with PE address of node information and standby PE address of node information with flow upstream PE node of PE node, preserves the corresponding relation of the affiliated standby PE address of node information of client address information and this client simultaneously.

For example: establish the master with being connected with 10 clients under the PE node, this is main, and then wherein 5 clients are distributed to first standby PE node with corresponding two the standby PE nodes of PE node, and other 5 clients are distributed to second standby PE node.

Step 302: main with the client terminal start-up under the PE node, the standby PE node under this client and this main VPN routing iinformation that sends self with the flow upstream PE node of PE node.

Step 303: flow upstream PE node is preserved this VPN routing iinformation after receiving the VPN routing iinformation that client sends.

Step 304: after standby PE node is received the VPN routing iinformation that client sends, the VPN route network segment/mask information of this VPN routing iinformation correspondence and VPN exchanging visit control information, the next-hop address information of self, self LSR-ID etc. are carried in the summary info field of label distribution related protocol message, the VPN routing tag of this VPN routing iinformation correspondence are carried at send to flow upstream PE node in the label distribution related protocol message simultaneously.

Step 305: after flow upstream PE node was received label distribution related protocol message, the VPN exchanging visit control information according to this message is carried judged whether to accept this message, if, execution in step 306; Otherwise, execution in step 308.

Step 306: flow upstream PE node judges whether to find the VPN route network segment information that this message is carried in the VPN route network segment information of the VPN routing iinformation that all clients of self preserving are sent, if, execution in step 307; Otherwise, execution in step 308.

Step 307: whether the next-hop address information that flow upstream PE node carries according to this message uses PE address of node information identical with corresponding the leading of this standby PE node of self preserving, and the decision rule of self preserving, determine whether to accept this standby PE node, if, execution in step 309; Otherwise, execution in step 308.

Step 308: flow upstream PE node is abandoned this standby PE node, and in client address information and standby PE node address information that self preserves, deletes this standby PE address of node information, goes to step 310.

Step 309: flow upstream PE node generates standby forwarding-table item according to this message, and this standby forwarding-table item comprises: the next-hop address information of the VPN route network segment/mask information, VPN routing tag information, standby PE node etc.

Step 310: flow upstream PE node is prepared to send message to main with the client under the PE node, detect main unreachable with the PE node, according to the client address information of self preserving and the corresponding relation of standby PE node address information, find the standby PE node address information of this master with the address information correspondence of the client under the PE node.

Step 311: flow upstream PE node is searched the standby forwarding-table item of this standby PE node correspondence in the fib table item, transmits this message according to this standby forwarding-table item that finds.

Fig. 4 is that the system that carries out fault recovery provided by the invention forms schematic diagram, and as shown in Figure 4, it mainly comprises: standby PE node configuration module 41, active and standby PE nodal information preserve module 42 and standby PE node is selected module 43, wherein:

Standby PE node configuration module 41: be used to the two or more standby PE nodes of flow downstream PE node configuration, main corresponding relation with PE node address information and standby PE node address information sent to active and standby PE nodal information preserve module 42.

Standby PE node configuration module 41 further can be used for, and the client under the PE node is distributed to each standby PE node respectively, the corresponding relation of client address information and standby PE node address information is sent to active and standby PE nodal information preserve module 42.

Active and standby PE nodal information is preserved module 42: be used to preserve the main corresponding relation with PE node address information and standby PE node address information that standby PE node configuration module 41 is sent, and the main VPN routing iinformation of sending with the client under the PE node of preservation, as if the VPN exchanging visit control information of sending according to standby PE node, the main VPN route network segment/mask information with the client under the PE node, the next-hop address information of standby PE node determines to accept this standby PE node, then generates to comprise: the VPN route network segment/mask information that standby PE node is sent, the standby forwarding-table item of VPN routing tag information and next-hop address information; If determine this standby PE node of refusal, then in the main corresponding relation of self preserving, delete this standby PE address of node information with PE node address information and standby PE node address information; Select the request of module 43 according to standby PE node, main standby PE address of node information with PE node correspondence is sent to standby PE node select module 43, and select the request of module 43 according to standby PE node, the standby forwarding-table item of correspondence is sent to standby PE node select module 43.

Active and standby PE nodal information is preserved module 42 and is further used for, indicate the weighted value of flow of the backup path of this standby PE node correspondence according to standby PE node being used to of sending, determine the priority of this standby PE node, preserve the precedence information of this standby PE node, select the request of module 43 according to standby PE node, the precedence information of this standby PE node is sent to standby PE node select module 43;

Perhaps, active and standby PE nodal information is preserved module 42 and is further used for, receive and preserve the main corresponding relation that standby PE node configuration module 41 is sent with PE node address information and standby PE node address information, request according to standby PE node selection module 43 sends to standby PE node with the standby PE nodal information corresponding with this client address information and selects module 43.

Standby PE node is selected module 43: be used for detect main with the PE node when unreachable, preserve this main standby PE address of node information of module 42 requests to active and standby PE nodal information with the PE node, according to predefined selective rule, in the standby PE node of the standby PE node address information correspondence that active and standby PE nodal information preservation module 42 is returned, select a standby PE node, and preserve the standby forwarding-table item of module 42 these standby PE node correspondences of request to active and standby PE nodal information, preserve the standby forwarding-table item that module 42 returns according to active and standby PE nodal information and message is mail to main with the client under the PE node.

Standby PE node selects module 43 to be further used for, preserve the precedence information of the standby PE node of module 42 requests to active and standby PE nodal information, preserve standby PE address of node information and the precedence information that module 42 is sent according to active and standby PE nodal information, select the highest standby PE node of priority, and preserve the standby forwarding-table item of module 42 these standby PE node correspondences of request to active and standby PE nodal information;

Perhaps, standby PE node selects module 43 to be further used for, preserve module 42 according to client address information to active and standby PE nodal information and ask the standby PE address of node information corresponding, and preserve the standby forwarding-table item of module 42 these standby PE node correspondences of request to active and standby PE nodal information with this client address information.

For more clearly describing the present invention, now provide an object lesson and describe:

As shown in Figure 5, PE1 is a flow upstream PE node, and PE2, PE3, PE4 are flow downstream PE node, and P1, P2, P3, P4 are router, and CE is the client under the PE2.When network design, PE3 and PE4 are configured to the standby PE node of PE2, then PE2 is the main PE node of using, then PE1-P1-P2-PE2-CE is a primary path, PE1-PE4-P4-P3-PE3-PE2-CE, PE1--P1-P4-P3-PE3-PE2-CE are backup path, if two backup path be used to indicate the weighted value of flow to be respectively 0.5 and 0.4, when PE1 detects primary path when unreachable, select the bigger backup path of weighted value: PE1-PE4-P4-P3-PE3-PE2-CE mails to CE with message.

The above only is process of the present invention and method embodiment, in order to restriction the present invention, all any modifications of being made within the spirit and principles in the present invention, is not equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1, a kind of fault protecting method; it is characterized in that; for flow downstream Provider Edge PE node is provided with two or more standby PE nodes; the flow upstream PE node of this flow downstream PE node is preserved this flow downstream PE node promptly: main corresponding relation with PE address of node information and standby PE address of node information comprises:

Client terminal start-up under the described flow downstream PE node, the virtual private network routing iinformation that sends this client to the standby PE node and the flow upstream PE node of described flow downstream PE node, standby PE node sends to flow upstream PE node with the VPN route network segment information and the VPN exchanging visit control information of this VPN routing iinformation correspondence, flow upstream PE node is according to VPN route network segment information and VPN exchanging visit control information, judge whether to accept the standby PE node of this standby PE node as described flow downstream PE node, if flow upstream PE node generates the standby forwarding-table item of this standby PE node; Perhaps, client terminal start-up under the described flow downstream PE node, the VPN routing iinformation that sends this client to the standby PE node and the flow upstream PE node of described flow downstream PE node, standby PE node sends to flow upstream PE node with the VPN route mask information and the VPN exchanging visit control information of this VPN routing iinformation correspondence, flow upstream PE node is according to VPN route mask information and VPN exchanging visit control information, judge whether to accept the standby PE node of this standby PE node as described flow downstream PE node, if flow upstream PE node generates the standby forwarding-table item of this standby PE node;

Flow upstream PE node detection is main unreachable with the PE node to the flow downstream, in all standby PE nodes of this flow downstream PE node, select a standby PE node, according to the standby forwarding-table item of this standby PE node correspondence, message is sent to main with the client under the PE node by this standby PE node.

2, the method for claim 1 is characterized in that, also comprises: for described each standby PE node is provided with a weight that is used to indicate by the flow on the backup path of this standby PE node correspondence;

3, method as claimed in claim 2 is characterized in that,

Described standby PE node is with the VPN route network segment information and the VPN exchanging visit control information of this VPN routing iinformation correspondence, further comprise when perhaps the VPN route mask information of this VPN routing iinformation correspondence and VPN exchanging visit control information being sent to flow upstream PE node: described standby PE node sends to flow upstream PE node with the weighted value of self, and flow upstream PE node is determined the priority of this standby PE node according to the weighted value of this standby PE node;

Described flow upstream PE node selects a standby PE node to be according to the weighted value of described each standby PE node: flow upstream PE node is selected a standby PE node that priority is the highest according to the priority of each standby PE node.

4, the method for claim 1, it is characterized in that the client under the described flow downstream PE node further comprises: standby PE node sends to flow upstream PE node with the next-hop address information of self after the standby PE node of flow downstream PE node sends the VPN routing iinformation of this client;

And, described flow upstream PE node is according to VPN route network segment information and VPN exchanging visit control information, judging whether to accept this standby PE node comprises as the standby PE node of described flow downstream PE node: flow upstream PE node is according to the VPN control information of exchanging visits, judge whether to receive the information that standby PE node is sent, if, judge whether in the VPN route network segment information of the VPN routing iinformation that all clients of self preserving are sent, find the VPN route network segment information that standby PE node is sent, if, whether identical according to this next-hop address information with the main PE address of node information of using, and preset rule, determine whether to accept this standby PE node.

5, method as claimed in claim 3, it is characterized in that, standby PE node is with VPN route network segment information, VPN exchanging visit control information and the weighted value of self, perhaps VPN route mask information, VPN exchanging visit control information and the weighted value of self being sent to flow upstream PE node is: by with VPN route network segment information, VPN exchanging visit control information and the weighted value of self, perhaps VPN route mask information, VPN exchanging visit control information and the weighted value of self are carried at and send to flow upstream PE node in the label distribution related protocol message.

6, method as claimed in claim 5, it is characterized in that described label distribution related protocol is: the tag distribution protocol CR-LDP of tag distribution protocol LDP or route restriction or at the RSVP of traffic engineering expansion RSVP-TE or multi-protocols border gateway protocol MP-BGP.

7, the method for claim 1 is characterized in that, all clients under the flow downstream PE node are distributed to each standby PE node of this flow downstream PE node respectively, the corresponding relation of record client-side information and standby PE nodal information;

8, a kind of fault recovery system is characterized in that, comprising: standby PE node configuration module, active and standby PE nodal information preserve module and standby PE node is selected module, wherein:

Active and standby PE nodal information is preserved module, the next-hop address information that is used for main VPN exchanging visit control information, VPN route network segment information and the standby PE node with the client under the PE node sent according to standby PE node determines whether this standby PE node of acceptance, if, generation comprises: the standby forwarding-table item of the next-hop address information of VPN route network segment information, VPN routing tag information and standby PE node, request according to standby PE node selection module sends to standby PE node with standby forwarding-table item and selects module; Perhaps, the next-hop address information of main VPN exchanging visit control information, VPN route mask information and the standby PE node of sending according to standby PE node with the client under the PE node, determine whether to accept this standby PE node, if, generation comprises: the standby forwarding-table item of the next-hop address information of VPN route mask information, VPN routing tag information and standby PE node, request according to standby PE node selection module sends to standby PE node with standby forwarding-table item and selects module;

9, system as claimed in claim 8, it is characterized in that, described active and standby PE nodal information is preserved module and is further used for, indicate the weighted value of flow of the backup path of this standby PE node correspondence according to standby PE node being used to of sending, determine the priority of this standby PE node, according to request, the precedence information of this standby PE node is sent to standby PE node select module;

10, system as claimed in claim 8, it is characterized in that, described standby PE node configuration module is further used for, client under the PE node is distributed to each standby PE node respectively, the corresponding relation of client address information and standby PE node address information is sent to active and standby PE nodal information preserve module;