CN101924642B - Method and device for protecting Ethernet with shared link - Google Patents

Abstract

The invention discloses an Ethernet protection method with a shared link, comprising: a domain terminal bridge (DEB) in a segment protection domain of an Ethernet with a shared link detects a connectivity check message (CCM) on a main path ; If the DEB does not receive the CCM sent by the primary interconnection bridge (PIB) and the alternative interconnection bridge (AIB) along the primary path within the predetermined time, when it is determined that the backup path in the segment protection domain is available, the primary path will be The data flow is switched to the backup path. The present invention also provides an Ethernet protection device with a shared link, which solves the problem of unnecessary switching that is prone to occur in the prior art when protecting an Ethernet with a shared link, which causes network traffic oscillation and communication problem of temporary interruption.

Description

A kind of Ethernet protection method and device with shared link

technical field

The invention relates to the link protection technology of the Ethernet, in particular to an Ethernet protection method and device with a shared link.

Background technique

With the introduction of the concept of Carrier Ethernet (CE, Carrier Ethernet) to meet the needs of telecom networks, and the connection-oriented Ethernet technology-Provider Backbone Transport (PBT, Provider BackboneTransport) technology has also emerged. Subsequently, operators at home and abroad adopted PBT technology to form a network, which provided a good start for the development of PBT technology in the metropolitan area network.

PBT technology is an improvement to the Provider Backbone Bridge (PBB, Provider Backbone Bridge) technology defined by the Institute of Electrical and Electronics Engineers (IEEE, Institute of Electrical and Electronics Engineers) 802.1ah. IEEE also refers to PBT technology as the carrier backbone that supports traffic engineering. Bridge technology (PBB-TE, Provider Backbone Bridge Traffic Engineering). According to the PBB-TE technology, the CE source device inserts the backbone network destination MAC (MediaAccess Control) address (B-DA, Backbone Destination MAC Address) and the backbone network source MAC address ( B-SA, Backbone Source MAC Address), Backbone Virtual Local Area Network Identity (B-VID, Backbone Virtual Local Area Network Identity) and Service Instance Tag (I-TAG, Service Instance TAG). The forwarding path between the CE source device and the destination device is pre-configured statically, and the intermediate CE device can forward the data frame based on the B-DA and B-VID in the forwarding table.

In order to make Ethernet reach the standard of telecom level, PBB-TE usually adopts protection technology. As shown in Figure 1, it is a schematic diagram of end-to-end linear protection of Ethernet tunnels in the prior art, where the end-to-end main tunnel of a traffic engineering service instance is TN1: PE1←→P1←→P2←→P3←→ PE2, PE1 and PE2 represent the ends of the tunnel instance, and TN2: PE1←→P5←→P6←→PE2 is the end-to-end backup tunnel of the traffic engineering service instance. In order to distinguish the above TN1 and TN2, the B-VID is specified as B-VLAN1 for TN1 during pre-configuration, and the B-VID is specified as B-VLAN2 for TN2. PBB-TE uses the connectivity fault management (CFM, Connectivity Fault Management) mechanism in IEEE 802.1ag to continuously monitor the tunnel status in the network. When TN1 fails, the data flow can be switched to the pre-established TN2.

In the prior art, the connectivity of the tunnel is detected by sending a continuity check message (CCM, Continuity CheckMessage) in the tunnel. For example: in the above-mentioned Figure 1, PE1 and PE2 send CCMs to each other along TN1 and TN2 respectively, and the CCMs of TN1 and TN2 encapsulate B-VLAN1 and B-VLAN2 respectively.

The above method realizes the full path protection of the tunnel, but the protection switching takes a long time and involves many nodes. Therefore, IEEE proposed a PBB-TE section protection scheme, as shown in Figure 2, P1-P2-P3 is a part of the path that carries the end-to-end main tunnel TN1 (PE1←→P1←→P2←→P3←→PE2) A physical link, also called a segment; a backup physical link P1-P4-P3 can be set to protect P1-P2-P3. This segment protection scheme is different from the foregoing end-to-end protection scheme in that: the segment protection scheme is based on physical link protection, while the end-to-end protection scheme is based on tunnel protection.

In order to implement the PBB-TE segment protection function, CCM messages need to verify their integrity on the primary segment and the backup segment of the segment protection domain at the same time. As shown in Figure 2, P1 and P3 send CCMs to each other along the primary segment P1-P2-P3 and the backup segment P1-P4-P3 respectively, and the CCMs of the primary segment and the backup segment respectively encapsulate corresponding B-VLANs. This method achieves good protection for the local path of the tunnel.

The fact that there are shared links between PBB-TE segment protection domains is a research hotspot in the current segment protection, as shown in Figure 3, there are two Ethernet switch paths (ESP, Ethernet Switch Path) in the figure, and the tunnel ESP1 The segment protection domain 1 and segment protection domain 2 of <X, Y, 1> and ESP2 <Y, X, 2> have a shared path B-M-E. In segment protection domain 1, the primary segment of ESP1 and ESP2 is A-B, and the backup segment is A-F-E-M-B; in segment protection domain 2, the primary segment of ESP1 and ESP2 is C-B, and the backup segment is C-D-E-M-B.

In order to realize the segment protection function with the shared link topology shown in Figure 3, a solution proposed by the prior art is shown in Figure 4 and Figure 5. In order to perform segment protection on ESP1 and ESP2, on the shared path B-M-E A primary interconnecting bridge (PIB, Primary Interconnecting Bridge) and an alternate interconnecting bridge (AIB, Alternate Interconnecting Bridge) are generated, node B is the PIB, and node E is the AIB. In addition, node A in segment protection domain 1 is a domain end point bridge (DEB, Domain Endpoint Bridge), and node C in segment protection domain 2 is a DEB. In segment protection domain 1, node A (DEB) and node B (PIB) send CCM on primary segment A-B and backup segment A-F-E-M-B respectively to detect whether the primary segment and backup segment are intact; node A (DEB) and node E(AIB) respectively send CCMs on the substitute primary segment A-B-M-E and the substitute backup segment A-F-E to detect whether the substitute primary segment and the substitute backup segment are intact. Similarly, in segment protection domain 2, node C (DEB) and node B (PIB) send CCMs on the primary segment C-B and backup segment C-D-E-M-B respectively to detect whether the primary segment and the backup segment are intact; node C (DEB ) and node E (AIB) respectively send CCMs on the substitute primary segment C-B-M-E and the substitute backup segment C-D-E to detect whether the substitute primary segment and the substitute backup segment are intact.

DEB only detects the primary segment and the backup segment in the segment protection domain to which it belongs, but is not responsible for detecting the replacement primary segment and backup segment; PIB detects the primary segment and backup segment in the two segment protection domains to which it belongs; The alternative primary segment and the alternative backup segment are detected within the two segment protection domains to which it belongs.

As shown in Figure 6, when the link <A, B> fails, node A cannot receive the CCM sent by node B on the main segment A-B within a certain period of time, and node A will send the CCM on the main segment A-B. All transmitted tunnels (such as ESP1) are switched to the backup segment A-F-E-M-B. Similarly, if Node B cannot receive the CCM sent by Node A on the primary segment A-B within a certain period of time, Node B will switch all tunnels (such as ESP2) transmitted on the primary segment A-B to the backup segment A-F-E-M-B. Subsequently, the latest paths of ESP1 and ESP2 in the two segment protection domains with shared links become: A-F-E-M-B-C.

Although the above-mentioned main mechanisms of DEB, PIB and AIB can well solve the problem of link failure, in some cases unnecessary switching will occur, resulting in network traffic oscillation and temporary interruption of communication. For example: as shown in Figure 7, both the link <A, B> of segment protection domain 1 and the link <B, C> of segment protection domain 2 have failed, and node A cannot receive node B within a certain period of time. For the CCM sent to it on the primary segment, node A will switch all the tunnels (such as ESP1) transmitted on the primary segment A-B to the backup segment; similarly, node B will not receive the CCM from node A within a certain period of time. For the CCM sent to it on the primary segment, Node B will switch all the tunnels (such as ESP2) transmitted on the primary segment A-B to the backup segment. In segment protection domain 1, node E cannot receive the CCM sent by node A on the alternative primary segment within a certain period of time, and node E will send all tunnels on the alternative primary segment of segment protection domain 1 (such as ESP2) Switch to the alternative backup segment; similarly, in the segment protection domain 2, node E cannot receive the CCM sent by node B on the alternative primary segment within a certain period of time, and node E will replace the segment protection domain 2 All tunnels (such as ESP1) on the primary segment are switched to the alternate backup segment. The paths of ESP1 and ESP2 in segment protection domain 1 and segment protection domain 2 become: A-F-E-D-C.

If the faults of links <A, B> and <B, C> are recovered and both segment protection domain 1 and segment protection domain 2 are in the non-reversal mode (the link will not be switched from the backup segment to the primary segment after the fault is restored) work, then the paths of ESP1 and ESP2 in segment protection domain 1 and segment protection domain 2 continue to be: A-F-E-D-C.

If the link on the shared link fails, as shown in Figure 8, the link <B, M> fails, and node A cannot receive the message sent by node B on the backup segment A-F-E-M-B within a certain period of time. CCM, node A will switch all tunnels (ESP1) transmitted on the backup segment to the main segment A-B; similarly, node C cannot receive the CCM sent by node B on the backup segment B-M-E-D-C within a certain period of time, node C C will switch all the tunnels (such as ESP2) transmitted on the backup segment B-M-E-D-C to the primary segment C-B. The paths of ESP1 and ESP2 in Segment Protection Domain 1 and Segment Protection Domain 2 become: A-B-C, however, in the case that the path remains A-F-E-D-C as shown in Figure 7, when the shared link fails, the A-F-E-D-C path The data stream transmission will not cause any impact, and there is no need to switch the path to the path A-B-C shown in FIG. 8 .

It can be seen from this that, in the prior art, when solving the failure of the shared link, an unnecessary switching (switching shown in FIG. 8 ) occurs, which easily leads to oscillation of network traffic and temporary interruption of communication.

Contents of the invention

In view of this, the main purpose of the present invention is to provide an Ethernet protection method and device with a shared link, so as to solve the problems in the prior art that easily lead to oscillation of network traffic and temporary interruption of communication.

In order to achieve the above object, technical solution of the present invention is achieved in that way:

The invention provides an Ethernet protection method with a shared link, the method comprising:

The domain termination bridge DEB in the segment protection domain of the Ethernet with shared links detects the connectivity check message CCM on the main path;

If the DEB does not receive the CCM sent by the primary interconnection bridge PIB and the alternative interconnection bridge AIB along the primary path within a predetermined time, when it is determined that the backup path in the segment protection domain is available, the primary path The data flow on the switch is switched to the backup path.

said primary path includes a primary segment and a substitute primary segment,

The DEB detects the CCM on the main path, specifically: the DEB simultaneously detects the CCM sent by the PIB along the main section, and the CCM sent by the AIB along the substitute main section.

The backup path includes a backup segment and a replacement backup segment,

When it is determined that the backup path is available, switching the data flow on the primary path to the backup path is specifically: when the DEB determines that the backup segment or the alternate backup segment is fault-free, switching the data flow on the primary path to a backup segment or an alternate backup segment.

After the data flow is switched to the backup path, the method further includes: the DEB detects the CCM on the backup path, if within a predetermined time, the DEB does not receive the CCM sent by the PIB and AIB along the backup path, Then, when it is determined that the primary section or the substitute primary section of the primary path is not faulty, the data flow on the backup path is switched to the primary section or the substitute primary section.

The method further includes:

The PIB detects the CCM of the primary segment and the backup segment of the segment protection domain to which it belongs, and if the PIB does not receive the CCM sent by the DEB along the primary segment within a predetermined time, when it is determined that the backup segment is fault-free , switch the data flow on the primary segment to the backup segment;

If the PIB does not receive the CCM sent by the DEB along the backup segment within a predetermined time, it switches the data flow on the backup segment to the primary segment when it is determined that the primary segment is faultless.

The method further includes:

The AIB detects the CCM of the alternative main segment and the alternative backup segment of the segment protection domain to which it belongs, and if the AIB does not receive the CCM sent by the DEB along the alternative main segment within a predetermined period of time, it determines that the alternative backup When there is no fault in the segment, switch the data flow on the substitute primary segment to the substitute backup segment;

If the AIB does not receive the CCM sent by the DEB along the substitute backup segment within a predetermined time, it switches the data flow on the substitute backup segment to the substitute master segment when it is determined that the substitute master segment is faultless.

The present invention also provides an Ethernet protection device with a shared link, the device comprising:

The detection module is used to detect the CCM of the DEB on the main path in the segment protection domain of the Ethernet with the shared link, and obtain the detection result;

Switching module, for according to the detection result, if the DEB does not receive the CCM sent by the PIB and AIB along the main path within a predetermined time, when it is determined that the backup path in the protection domain of the section is available, switch the main path The data flow on the path is switched to the backup path.

said primary path includes a primary segment and a substitute primary segment,

The detection module is further configured to simultaneously detect the CCM sent by the PIB to the DEB along the main section, and the CCM sent by the AIB to the DEB along the substitute main section.

The backup path includes a backup segment and a replacement backup segment,

The switching module is further configured to switch the data flow on the main path to the backup section or the substitute backup section when it is determined that the backup section and the substitute backup section are not faulty.

The detection module is further used to detect the CCM of the DEB on the backup path, and obtain the detection result;

Correspondingly, the switching module is further configured to, according to the detection result, if the DEB does not receive the CCM sent by the PIB and AIB along the backup path within a predetermined time, then determine the main path of the main path or When the replacement primary segment is faultless, the data flow on the backup path is switched to the primary segment or the replacement primary segment.

A kind of Ethernet protection method and device with shared link provided by the present invention, detect the CCM on the main path by the DEB in the segment protection domain of the Ethernet with shared link; If within the predetermined time, DEB does not After receiving the CCM sent by the PIB and AIB along the primary path, when it is determined that the backup path in the segment protection domain is available, the data flow on the primary path is switched to the backup path. When the present invention protects the Ethernet with a shared link, unnecessary switching is avoided, thereby solving the problems of oscillation of network flow and temporary interruption of communication caused by unnecessary switching.

Description of drawings

FIG. 1 is a schematic diagram of end-to-end linear protection of an Ethernet tunnel in the prior art;

FIG. 2 is a schematic diagram of segment protection of an Ethernet tunnel in the prior art;

FIG. 3 is a schematic diagram of a topology structure of multi-segment protection domains with shared links in the prior art;

FIG. 4 is a schematic diagram 1 of performing fault detection on a topology structure with shared links in the prior art;

FIG. 5 is a second schematic diagram of fault detection for a topology with a shared link in the prior art;

6 is a schematic diagram 1 of link protection switching with a shared link topology in the prior art;

7 is a second schematic diagram of link protection switching with a shared link topology in the prior art;

FIG. 8 is a third schematic diagram of link protection switching with a shared link topology in the prior art;

9 is a flow chart of an Ethernet protection method with a shared link in the present invention;

10 is a schematic diagram of link protection switching with a shared link topology in an embodiment of the present invention;

FIG. 11 is a schematic diagram of the composition and structure of an Ethernet protection device with a shared link according to the present invention.

Detailed ways

The technical solutions of the present invention will be further elaborated below in conjunction with the accompanying drawings and specific embodiments.

An Ethernet protection method with a shared link provided by the present invention, as shown in Figure 9, mainly includes the following steps:

Step 901 , the DEB in the segment protection domain of the Ethernet with the shared link detects the CCM on the primary path.

The present invention needs to pre-configure detection points on the DEB in each segment protection domain to detect the CCM on the main path. It should be pointed out that the main path in the present invention includes the main section and the alternative main section, and the DEB detects the CCM on the main path, specifically: the DEB simultaneously detects the CCM sent by the PIB along the main section, and the AIB sends along the alternative main section The CCM.

Step 902, if the DEB does not receive the CCM sent by the PIB and AIB along the main path within a predetermined time, then switch the data flow on the main path to the backup path when it is determined that the backup path in the segment protection domain is available.

It should be pointed out that the backup path in the present invention includes a backup segment and an alternative backup segment, and when it is determined that the backup path is available, the data flow on the main path is switched to the backup path, specifically: DEB determines the backup segment or the alternative When the backup segment is not faulty, the data flow on the primary path is switched to the backup segment or an alternate backup segment.

The above is for the case where the data flow on the main path is switched to the backup path. For the case where the data flow on the backup path is switched to the main path, similarly, it is necessary to configure detection points on the DEB in each segment protection domain in advance to detect CCM on the backup path (including the backup segment and the alternate backup segment); used to detect the CCM on the backup path (including the backup segment and the alternate backup segment), if the DEB does not receive the PIB and AIB along the backup path within the predetermined time (including the backup segment and the substitute backup segment), when it is determined that the primary segment or the substitute primary segment of the primary path is faultless, the data flow on the backup path is switched to the primary segment or the substitute primary segment.

In addition, the PIB in the present invention needs to detect the CCM of the main section and the backup section of the section protection domain to which it belongs. If within a predetermined time, the PIB does not receive the CCM sent by the DEB along the main section, then when it is determined that the backup section is faultless, Switch the data flow on the primary segment to the backup segment; if the PIB does not receive the CCM sent by the DEB along the backup segment within the predetermined time, it will switch the data flow on the backup segment to the primary segment when it is determined that the primary segment is faultless. paragraph. Correspondingly, a detection point needs to be configured in advance on the PIB in each segment protection domain to detect the CCM sent by the DEB along the primary segment and the backup segment.

The AIB also needs to detect the CCM of the alternative primary segment and the alternate backup segment of the protection domain to which it belongs. If the AIB does not receive the CCM sent by the DEB along the alternate primary segment within the predetermined time, it will The data flow on the alternative primary segment is switched to the alternative backup segment; if AIB does not receive the CCM sent by DEB along the alternative backup segment within the predetermined time, it will replace the data on the backup segment when it is determined that the alternative primary segment is faultless The flow is switched to the alternate primary segment. Correspondingly, a detection point needs to be configured in advance on the AIB in each segment protection domain, so as to detect the CCM sent by the AIB along the substitute primary segment and the substitute backup segment.

For the configuration of the above detection points, it should be noted that in each segment protection domain, the detection points of DEB on the primary segment correspond to the detection points of PIB on the primary segment, and the detection points of DEB on the backup segment correspond to the detection points of PIB on the backup segment. and the corresponding detection points of these two groups belong to different management unions; in each segment protection domain, the detection points of DEB on the replacement primary segment correspond to the detection points of AIB on the replacement backup segment, and the detection points of DEB on the replacement The detection points on the backup segment correspond to the detection points of the AIB on the alternate backup segment, and these two groups of corresponding detection points also belong to different management associations. Only two detection points belonging to a unified management association can send CCMs to each other.

The above-mentioned Ethernet protection method will be further elaborated below in combination with specific embodiments.

Still taking the Ethernet topology shown in Figure 4 and Figure 5 as an example, in segment protection domain 1, node A (DEB) and node B (PIB) send CCMs on the primary segment A-B and the backup segment A-F-E-M-B respectively, To detect whether the primary segment and the backup segment are intact; between node A (DEB) and node E (AIB), send CCM on the alternative primary segment A-B-M-E and the alternative backup segment A-F-E respectively, to detect whether the alternative primary segment and the alternative backup segment are intact. Similarly, in segment protection domain 2, node C (DEB) and node B (PIB) send CCMs on the primary segment C-B and backup segment C-D-E-M-B respectively to detect whether the primary segment and the backup segment are intact; node C (DEB ) and node E (AIB) respectively send CCMs on the substitute primary segment C-B-M-E and the substitute backup segment A-D-E to detect whether the substitute primary segment and the substitute backup segment are intact.

The link <A, B> of segment protection domain 1 and the link <B, C> of segment protection domain 2 are faulty, and node A (DEB) cannot receive the message from node B (PIB) within a certain period of time. The CCM sent to it on the segment, and the CCM sent to it by node E (AIB) on the replacement primary segment, node A will switch all the tunnels (such as ESP1) transmitted on the primary segment A-B to the backup segment. Similarly, node C (DEB) cannot receive the CCM sent to it by node B (PIB) on the primary segment within a certain period of time, and the CCM sent to it by node E (AIB) on the alternative primary segment, node C All tunnels (such as ESP2) transmitted on the primary segment C-B will be switched to the backup segment. Node B (PIB) cannot receive the CCM sent by node A (DEB) within a certain period of time on the primary segment, and node B will switch all tunnels (such as ESP2) transmitted on the primary segment A-B to the backup segment come up. Node E (AIB) cannot receive the CCM sent by node A (DEB) on the alternative primary segment within a certain period of time, and node E will switch all the tunnels (such as ESP2) on the alternate primary segment of segment protection domain 1 to the alternate backup segment. Similarly, in segment protection domain 2, node E (AIB) cannot receive the CCM sent by node B (DEB) on the alternative primary segment within a certain period of time, and node E will send the alternative primary segment of segment protection domain 2 All tunnels on the segment (such as ESP1) are switched over to the alternate backup segment. Thus, the final paths of ESP1 and ESP2 in segment protection domains 1 and 2 become: A-F-E-D-C.

If the faults of link <A, B> and link <B, C> are both recovered, and both segment protection domain 1 and segment protection domain 2 are in the non-reversal mode (the link will not be switched from the backup segment to the active segment), then the paths of ESP1 and ESP2 in segment protection domains 1 and 2 continue to be: A-F-E-D-C.

If the link on the shared path breaks down subsequently, as shown in Figure 10, the shared link <B, M> has broken down, according to the scheme of the present invention, although node A (DEB) cannot receive The CCM sent by node B (PIB) on the backup segment A-F-E-M-B, but can receive the CCM sent by node E (AIB) on the alternate backup segment A-F-E, therefore, node A will not transfer the transmission on the backup segment All tunnels (such as ESP1) are switched to the main segment A-B; similarly, although node C (DEB) cannot receive the CCM sent by node B (PIB) on the backup segment B-M-E-D-C within a certain period of time, it can receive To the CCM sent to node E (AIB) on the alternate backup segment E-D-C, therefore, node A will not switch all the tunnels (such as ESP2) transmitted on the backup segment to the primary segment B-C. Therefore, the paths of ESP1 and ESP2 in the segment protection domains 1 and 2 still remain as: A-F-E-D-C, avoiding an unnecessary switching, and further avoiding frequent switching of traffic.

It can be seen that, when the present invention protects the Ethernet with a shared link, unnecessary switching is avoided, thereby solving the problems of network traffic oscillation and temporary interruption of communication caused by unnecessary switching .

In order to realize the above-mentioned Ethernet protection method, the present invention also provides an Ethernet protection device with shared links, which is suitable for DEBs in the segment protection domain of Ethernet with shared links, as shown in Figure 11, the The device includes: a detection module 10 and a switching module 20 . The detection module 10 is configured to detect the CCM of the DEB on the main path in the segment protection domain of the Ethernet with a shared link, and obtain the detection result. Switching module 20 is used for, according to the detection result, if DEB does not receive the CCM that PIB and AIB send along the main path within a predetermined time, then when it is determined that the backup path in the segment protection domain is available, the data flow on the main path Switch to the backup path.

Wherein, the main path includes the main section and the substitute main section, and the detection module 10 is further used to simultaneously detect the CCM sent by the PIB to the DEB along the main section, and the CCM sent by the AIB to the DEB along the substitute main section.

The backup path includes a backup section and an alternate backup section, and the switching module 20 is further configured to switch the data flow on the main path to the backup section or the alternate backup section when it is determined that the backup section and the alternate backup section are faultless.

Preferably, the detection module 10 is further configured to detect the CCM of the DEB on the backup path, and obtain the detection result. Correspondingly, the switching module 20 is further used for, according to the detection result, if within a predetermined time, if the DEB does not receive the CCM sent by the PIB and AIB along the backup path, when it is determined that the primary section or the replacement primary section of the primary path is not faulty, Switch the data flow on the backup path to the primary segment or an alternate primary segment.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention.

Claims (10)

1. have an Ethernet guard method for shared link, it is characterized in that, have configuration detection point on territory terminal bridge DEB, main interconnection bridge PIB in the segment protect territory of Ethernet of shared link and alternative interconnection bridge AIB in advance at each, the method also comprises:

Described DEB detects the connectivity check messages CCM on main path;

If in the given time, described DEB does not receive the CCM that PIB and AIB send along described main path, when the backup path in determining described segment protect territory is available, the data flow on main path is switched on backup path;

Wherein, in each segment protect territory, the test point of the corresponding PIB of the test point of DEB in principal piece in principal piece, the test point of the corresponding PIB of the test point of DEB in backup segment in backup segment, and these two groups of corresponding test points belong to respectively different management associatings; DEB is substituting the test point in backup segment at the test point corresponding A IB substituting in principal piece, and DEB is substituting the test point in backup segment at the test point corresponding A IB substituting in backup segment, and these two groups of corresponding test points also belong to respectively different management associatings.

2. have according to claim 1 the Ethernet guard method of shared link, it is characterized in that, described main path comprises principal piece and alternative principal piece,

Described DEB detects the CCM on main path, is specially: described DEB detects the CCM that PIB sends along principal piece simultaneously, and AIB is along the CCM that substitutes principal piece transmission.

3. have according to claim 1 the Ethernet guard method of shared link, it is characterized in that, described backup path comprises backup segment and alternative backup segment,

Describedly when definite backup path is available, data flow on main path is switched on backup path, is specially: described DEB, when definite described backup segment or alternative backup segment fault-free, is switched to the data flow on main path in backup segment or alternative backup segment.

4. according to the Ethernet guard method described in claim 1 or 2 or 3 with shared link; it is characterized in that; after data flow is switched on backup path; the method further comprises: described DEB detects the CCM on backup path; if in the given time; described DEB does not receive the CCM that PIB and AIB send along described backup path;, when determining the principal piece of described main path or alternative principal piece fault-free, the data flow on backup path is switched in described principal piece or alternative principal piece.

5. according to the Ethernet guard method described in claim 1 or 2 or 3 with shared link, it is characterized in that, the method further comprises:

Described PIB detects the principal piece in its affiliated segment protect territory and the CCM of backup segment, if in the given time, described PIB does not receive the CCM that DEB sends along described principal piece,, when determining described backup segment fault-free, the data flow in principal piece is switched in backup segment;

If in the given time, described PIB does not receive the CCM that DEB sends along described backup segment,, when determining described principal piece fault-free, the data flow in backup segment is switched in principal piece.

6. according to the Ethernet guard method described in claim 1 or 2 or 3 with shared link, it is characterized in that, the method further comprises:

Described AIB detects the alternative principal piece in its affiliated segment protect territory and the CCM of alternative backup segment, if in the given time, described AIB does not receive the CCM that DEB sends along described alternative principal piece,, when determining described alternative backup segment fault-free, the data flow substituting in principal piece is switched in alternative backup segment;

If in the given time, described AIB does not receive the CCM that DEB sends along described alternative backup segment,, when determining described alternative principal piece fault-free, the data flow substituting in backup segment is switched in alternative principal piece.

7. an Ethernet protective device with shared link, is characterized in that, has configuration detection point on DEB, PIB in the segment protect territory of Ethernet of shared link and AIB in advance at each, and this device comprises:

Detection module, the CCM for detection of described DEB on main path, and obtain testing result;

Switch module, for according to described testing result, if in the given time, described DEB does not receive the CCM that PIB and AIB send along main path, when the backup path in determining described segment protect territory is available, the data flow on main path is switched on backup path;

Wherein, in each segment protect territory, the test point of the corresponding PIB of the test point of DEB in principal piece in principal piece, the test point of the corresponding PIB of the test point of DEB in backup segment in backup segment, and these two groups of corresponding test points belong to respectively different management associatings; DEB is substituting the test point in backup segment at the test point corresponding A IB substituting in principal piece, and DEB is substituting the test point in backup segment at the test point corresponding A IB substituting in backup segment, and these two groups of corresponding test points also belong to respectively different management associatings.

8. the Ethernet protective device according to claim 7 with shared link, is characterized in that, described main path comprises principal piece and alternative principal piece,

Described detection module is further used for, and detects the CCM that described PIB sends along principal piece to DEB simultaneously, and described AIB is along substituting the CCM of principal piece to DEB transmission.

9. the Ethernet protective device according to claim 7 with shared link, is characterized in that, described backup path comprises backup segment and alternative backup segment,

The described module of switching is further used for, and when definite described backup segment and alternative backup segment fault-free, the data flow on main path is switched in backup segment or alternative backup segment.

10. according to the Ethernet protective device described in claim 7 or 8 or 9 with shared link, it is characterized in that, described detection module is further used for, and detects the CCM of DEB on backup path, and obtains testing result;

Accordingly, the described module of switching is further used for, according to described testing result, if in the given time, described DEB does not receive the CCM that PIB and AIB send along backup path,, when determining the principal piece of described main path or alternative principal piece fault-free, the data flow on backup path is switched in described principal piece or alternative principal piece.