WO2012109912A1

WO2012109912A1 - Rerouting method and point of local repair node

Info

Publication number: WO2012109912A1
Application number: PCT/CN2011/081175
Authority: WO
Inventors: 付志涛; 许浩; 金昊
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-02-17
Filing date: 2011-10-24
Publication date: 2012-08-23
Also published as: CN102158397B; CN102158397A

Abstract

Provided in the present invention are a rerouting method and a point of local repair (PLR) node. The method comprises: when the PLR node receives a resource reservation (RESV) message, if, on the basis of downstream node information attached to the RESV message, a preconfigured backup tunnel destination node is judged as not meeting a rerouting requirement, then searching within the downstream node information for a downstream node meeting the rerouting requirement; if an label-switched path (LSP) between the downstream node found and the PLR node is judged as not to coincide with a primary LSP, then selecting the LSP between the downstream node and the PLR node and the primary LSP to form a rerouting relationship. The method and the PLR node improve the protection relationship of cross-node protection, and ensure that switch protection goes into effect during a malfunction of two consecutive sections of the link.

Description

A method of rerouting and a local repair point node

Technical field

The present invention relates to the field of data network communication, and in particular, to a method for rerouting and a local repair point node.

Background technique

Traffic Engineering-Fast Re-Route (TE-FRR) technology is a local protection technology that performs local repair when local links or nodes fail. Two types of local protection, link protection and node protection, are defined in RFC4090. Two special node types in the protection process are also defined: Point Local Repair (PLR) nodes and convergence points ( Merge Point, referred to as MP) node.

Figure 1 shows the node protection topology of TE-FRR. As shown in FIG. 1, the topology diagram includes: nodes R1, R2, and R3 (R1 is a PLR node, and R3 is an MP node), and links are: L12, L23, and LI3, wherein the primary tunnel path (Primary lsp) is R1-R2-R3, the backup tunnel path (Backup lsp) is R1-R3. When the link L12 fails, the path is switched to L13 to form node protection.

Figure 2 shows the link protection topology of TE-FRR. As shown in FIG. 2, the topology map includes: nodes R1, R2, and R3 (R2 as a PLR node and R3 as an MP node), links: L12, L23, and L32, wherein the primary tunnel path (Primary lsp) is R1. -R2-R3, the backup tunnel path (Backup lsp) is R2-R3. When link L23 fails, the path is switched to L32 to form link protection. After the switchover, the MP node processes the protocol packets sent by the upstream, such as the PATH (Path) message and the PATH-TEAR (Path Removal) message sent from the backup tunnel. The protocol packets of the original tunnel are not processed.

In actual engineering deployment, a tunnel with TE-FRR attributes, except for the tail node, each of the other nodes is a potential PLR node. As shown in Figure 3, a cross-node protection is formed, where Primary ls is R1-R2-R3-R4, Backup ls l is R1-R3 (via link L13) Backup lsp2 is R2-R4 (via link L24) . Both nodes R1 and R2 act as PLR nodes, backup tunnel lspl protects R2 nodes, and backup tunnel Backup lsp2 protects R3 nodes. In the case of such protection, due to the failure of the link L23, node protection switching occurs as R2 of the PLR node at this time, and the upstream PATH signaling of the primary tunnel path reaches the R4 node (MP node) through L24. R4 also refreshes RESV (Resource Reservation) signaling upstream through L24. The R3 node is not refreshed. The status of the primary tunnel path protocol of the R3 is aging. After the aging, if the link L12 also fails, the node protection switching occurs as the R1 of the PLR node. The R3 becomes an MP node. However, the tunnel status information on the R3 is aged and cannot become an MP node. As a result, the switch is unsuccessful and the service of the tunnel is interrupted. Summary of the invention

The technical problem to be solved by the present invention is to provide a rerouting method and a local repair point node, so as to improve the protection relationship of the cross node protection and ensure continuous two-stage link failure, and the handover protection can take effect.

In order to solve the above technical problem, the present invention provides a method for rerouting, including: after receiving a resource reservation (RESV) message, the local repair point node determines a preset backup according to the information of the downstream node carried in the RESV message. If the tunnel destination node does not satisfy the rerouting condition, the downstream node information is searched for the downstream node that meets the rerouting condition, and if the tunnel path between the found downstream node and the local node does not coincide with the primary tunnel path, Then, the tunnel path between the downstream node and the local node is selected to form a rerouting relationship with the primary tunnel path. Preferably, the foregoing method further has the following features: before the step of determining, by the local repair point node, that the preset backup tunnel destination node does not satisfy the rerouting condition, the method further includes:

The local repair point node determines that the downstream path is switched.

Preferably, the foregoing method further has the following features: after the step of determining, by the local repair point node, that the preset backup tunnel destination node does not satisfy the rerouting condition, the method further includes:

The local repair point node releases the original rerouting relationship.

Preferably, the foregoing method further has the following features: the rerouting condition is:

The downstream node is the next hop router or the next next hop router of the local repair point node. Preferably, the foregoing method further has the following features: the downstream node information carried by the RESV message The information is achieved by:

The RESV message carries record routing object information, and the record routing object information includes at least interface information of the downstream node.

In order to solve the above problem, the present invention further provides a local repair point node, including: a first determining module, configured to: after receiving a resource reservation (RESV) message, determine a preset according to the downstream node information carried by the RESV message Whether the backup tunnel destination node meets the rerouting condition;

a locating module, configured to: after the first determining module determines that the rerouting condition is not met, search for, from the downstream node information, a downstream node that meets a rerouting condition;

a second judging module, configured to determine, when the search module finds a downstream node that satisfies the rerouting condition, whether the tunnel path between the found downstream node and the local node is coincident with the main tunnel path;

The selection module is configured to select a tunnel path between the downstream node and the local node to form a rerouting relationship with the primary tunnel path if the second determination module determines that the second determination module does not overlap. Preferably, the foregoing local repair point node further has the following features:

The third determining module is configured to: after receiving the RESV message, determine, according to the information of the downstream node that is carried by the RESV message, whether the downstream path is switched;

The first determining module determines whether the preset backup tunnel destination node satisfies the rerouting condition if the third determining module determines that the downstream path is switched.

Preferably, the foregoing local repair point node further has the following features:

And releasing the module, configured to cancel the original rerouting relationship if the first determining module determines that the preset backup tunnel destination node does not satisfy the rerouting condition.

Preferably, the local repair point node further has the following features: The rerouting condition is: the downstream node is a next hop router or a next next hop router of the local repair point node.

Preferably, the local repair point node has the following features: The downstream node information carried by the RESV message is implemented in the following manner:

The RESV message carries record routing object information, and the record routing object information is at least Includes interface information for downstream nodes.

In summary, the above-mentioned method of rerouting and the local repair point node can improve the protection relationship of the cross-node protection, and can avoid the failure of the adjacent two links, causing the loss of the data service caused by the tunnel protection failure, and ensuring continuous If the two links fail, the switch protection can take effect. BRIEF abstract

Figure 1 is a topology diagram of TE-FRR node protection;

Figure 2 is a topology diagram of TE-FRR link protection;

Figure 3 is a topology diagram of TE-FRR cross node protection;

4 is a flowchart of a method for rerouting according to an embodiment of the present invention;

FIG. 5 is a topological diagram of TE-FRR cross node protection applied in an embodiment of the present invention; FIG.

6 is a flowchart of a method for rerouting according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a PLR node according to an embodiment of the present invention.

Preferred embodiment of the invention

Embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other.

In order to prevent cross-node protection in the network, the two adjacent links can be prevented from being faulty, and the tunnel protection fails to cause data loss. The embodiment of the present invention provides a rerouting method, as shown in FIG. , including the following steps:

S10. After receiving the RESV message, the PLR node determines, according to the downstream node information carried in the RESV message, that the preset backup tunnel destination node does not satisfy the rerouting condition, and searches for the rerouting from the downstream node information. The downstream node of the condition,

S20. If the PLR node determines that the discovered tunnel path between the downstream node and the local node does not coincide with the primary tunnel path, the tunnel path and the primary tunnel path shape between the downstream node and the local node are selected. Heavy routing relationship.

The rerouting condition is: the downstream node is a next hop router or a next hop router of the local repair point node.

FIG. 5 is a topological diagram of TE-FRR cross-node protection according to an embodiment of the present invention. In the topology diagram shown in FIG. 5, the primary tunnel has an FRR attribute, and the RRO (Record Route Object) is carried in the RESV message. The routing object information, where the RRO information includes: interface information of the downstream node, Router1D (route identifier) information, and label information, where the interface information of the downstream node is necessarily carried.

The PLR node can check whether the preset backup tunnel destination node meets the NHOP (Next-hop Router, next hop router-and PLR one-hop router) or Ν 通过 by the RRO information carried in the RESV message (Next- Next-hop Router, the relationship between the next router and the router with two hops from the PLR. If it is not satisfied, the original FRR relationship is removed, and other downstream nodes that satisfy the NHOP or N HOP relationship are selected to re-form the new FRR relationship. , so that the protection switch can take effect.

In this embodiment, in the case that the primary tunnel path does not fail, when the RESV message reaches R1, the sub-objects carried in the RRO in the RESV message are: the fei4/l interface address of R4 and the RouterlD address of R4 ( Optional), the inbound label of the primary tunnel path on R4, the fei3/2 interface address of R3, the RouterlD address of R3 (optional), the incoming label of the primary tunnel path on R3, the fei2/l interface address of R2, R2 RouterlD address (optional), the inbound label of the primary tunnel path on R2. In this way, R1 determines that the preset backup tunnel destination R3 forms an N HOP relationship with R1, and determines that Backup lspl can form a node protection relationship with the primary tunnel path, that is, form an FRR relationship.

When the link L23 is faulty, R2 is switched, and the signaling packet of the primary tunnel path is forwarded through the link L24. After the R2 switchover, the sub-objects carried in the RESV message RRO of the R2 node are: fei4/l interface address of R4 , R4's RouterlD address (optional), and the primary tunnel path's inbound label on R4. When the RESV message arrives at R1, the RRO sub-objects carried are: fei4/l interface address of R4, RouterlD address of R4 (optional), incoming label of R2 on the primary tunnel path, fei2/l interface address of R2, R2 RouterlD address (optional), the inbound label of the primary tunnel path on R2. At this time, R1 finds that the backup tunnel destination R3 is not in the RRO information. Therefore, it is determined that the destinations R3 and R1 of the backup tunnel do not satisfy the NHOP or N HOP relationship, and thus the corresponding FRR relationship is released. R1 finds that R4 and R1 are NNHOP relations from the new RESV message, and the tunnel between R1 and R4 and the primary tunnel path satisfy the non-coincident condition. At this time, Backup lsp3 can form a node protection relationship with the primary tunnel path, so Backup lsp3 and The main tunnel path forms a new FRR relationship.

When link L12 fails, R1 switches, and the status of the primary tunnel path on R2 and R3 is aged and deleted. The signaling of the primary tunnel is forwarded between L14. The tunnel is not interrupted, ensuring service traffic.

The method of rerouting according to the present embodiment will be described in detail below with reference to the topology diagram shown in FIG. 5. As shown in FIG. 6, the following steps are included: (Please verify whether the following process steps are accurate)

Step 101: R1 receives the RESV message;

Step 102, R1 determines whether the current primary tunnel path has an FRR relationship, if yes, then proceeds to step 103; otherwise, proceeds to step 107;

According to the protocol status, since RSVP is a soft state protocol, each node has state information. Each tunnel forms an FRR relationship on a certain node, and it has a status flag in the status block.

Step 103, R1 determines whether the downstream path is switched according to the received RESV message, if yes, go to step 105; otherwise, go to step 104;

Step 104: Without processing, the old FRR relationship can be protected;

Step 105: R1 determines whether the destination R3 and R1 of the preset backup tunnel meet the NHOP or NNHOP relationship. If yes, the process proceeds to step 104, and no processing is performed; otherwise, the process proceeds to step 106;

Step 106, the original FRR relationship is removed, and there is no FRR relationship with the main tunnel path in R1, and the process proceeds to step 102;

Step 107: R1 finds from the information carried in the RESV message whether there is a node that has a relationship with R1 that satisfies the NHOP or NNHOP relationship, and if yes, proceeds to step 108; otherwise, proceeds to step 109;

Step 108: R1 determines whether the tunnel between the node and the node searched in step 107 is related to the primary tunnel. If the paths are coincident, the tunnel between the node and the searched node is selected as the backup tunnel, and the FRR relationship is formed with the primary tunnel path; if they are coincident, the process proceeds to step 109;

Step 109. Cannot form protection and end.

The embodiment also provides a PLR node. As shown in FIG. 7, the PLR node in this embodiment includes: a first determining module, a searching module, a second determining module, and a selecting module, where

The first determining module is configured to: after receiving the RESV message, determine, according to the downstream node information carried in the RESV message, whether the preset backup tunnel destination node satisfies the rerouting condition;

The selection module is configured to select a tunnel path between the downstream node and the local node to form a rerouting relationship with the primary tunnel path if the second determination module determines that the second determination module does not overlap.

In a preferred embodiment, the PLR node may further include: a third determining module, configured to determine, according to the downstream node information carried in the RESV message, whether the downstream path is switched after receiving the RESV message. In this embodiment, the first determining module determines whether the preset backup tunnel destination node satisfies the rerouting condition if the third determining module determines that the downstream path is switched.

In a preferred embodiment, the PLR node may further include: a releasing module, configured to: after the first determining module determines that the preset backup tunnel destination node does not satisfy the rerouting condition, cancel the original Rerouting relationship.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be performed by a program to instruct the associated hardware, such as a read only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment can be used The form of hardware implementation can also be implemented in the form of software function modules. The invention is not limited to any specific form of combination of hardware and software.

The above is only a preferred embodiment of the present invention, and of course, the present invention may be embodied in various other embodiments without departing from the spirit and scope of the invention. Various changes and modifications may be made without departing from the scope of the appended claims.

INDUSTRIAL APPLICABILITY The above technical solution provides a rerouting method and a local repair point node to improve the protection relationship of the cross node protection, ensure continuous two-stage link failure, and the switching protection can take effect, and the adjacent two links can be avoided. The failure of the tunnel protection caused by the failure of the tunnel protection resulted in the loss of data services.

Claims

Claim

1. A method for rerouting, comprising:

After receiving the resource reservation (RESV) message, the local repair point node determines, according to the downstream node information carried in the RESV message, that the preset backup tunnel destination node does not satisfy the rerouting condition, and searches for the downstream node information. If the downstream node that meets the rerouting condition determines that the tunnel path between the found downstream node and the local node does not coincide with the primary tunnel path, the tunnel path between the downstream node and the local node is selected to form a tunnel path with the primary tunnel path. Rerouting relationship.

2. The method of claim 1, wherein: the method further comprises: before the step of the local repair point node determining that the preset backup tunnel destination node does not satisfy the rerouting condition, the method further comprising:

The local repair point node determines that the downstream path is switched.

The method of claim 1, wherein: after the step of the local repair point node determining that the preset backup tunnel destination node does not satisfy the rerouting condition, the method further includes:

The local repair point node releases the original rerouting relationship.

4. The method according to any one of claims 1-3, wherein: the rerouting condition is: the downstream node is a next hop router or a next next hop router of the local repair point node.

The method of claim 1, wherein: the downstream node information carried by the RESV message is record routing object information carried by the RESV message, and the record routing object information includes at least interface information of the downstream node.

6. A local repair point node, including:

a first determining module, configured to: after receiving a resource reservation (RESV) message, according to the

The downstream node information carried in the RESV message determines whether the preset backup tunnel destination node satisfies the rerouting condition;

a locating module, configured to: search for a downstream node that satisfies a rerouting condition from the downstream node information if the first determining module determines that the rerouting condition is not met;

a second judging module, configured to: if the searching module finds a downstream node that satisfies the rerouting condition, determine whether the tunnel path between the found downstream node and the local node is coincident with the main tunnel path; as well as And a selection module, configured to: when the second judging module determines that the coincidence is not coincident, the tunnel path between the downstream node and the local node is selected to form a rerouting relationship with the main tunnel path.

7. The local repair point node of claim 6, further comprising:

a third determining module, configured to: determine, according to the downstream node information carried in the RESV message, whether the downstream path is switched after receiving the RES V message;

The first determining module is configured to: determine, in the case that the third determining module determines that the downstream path is switched, whether the preset backup tunnel destination node satisfies the rerouting condition.

8. The local repair point node of claim 6, further comprising:

And the releasing module is configured to: when the first determining module determines that the preset grounding node of the backup tunnel does not satisfy the rerouting condition, cancel the original rerouting relationship.

9. The local repair point node according to any one of claims 6-8, wherein: the rerouting condition is:

The downstream node is the next hop router or the next next hop router of the local repair point node.

The local repair point node according to claim 6, wherein: the downstream node information carried by the RESV message is record routing object information carried by the RESV message, and the record routing object information includes at least interface information of a downstream node. .