WO2012171368A1

WO2012171368A1 - Tunnel reestablishment method and network element

Info

Publication number: WO2012171368A1
Application number: PCT/CN2012/072361
Authority: WO
Inventors: 杨帆
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-06-17
Filing date: 2012-03-15
Publication date: 2012-12-20
Also published as: CN102223280B; CN102223280A

Abstract

A tunnel reestablishment method and a network element. The method includes: a node in a tunnel label switching path (LSP) receiving a first path message, and if a path state control block of an old LSP within the same tunnel is found when establishing a path state control block for a new LSP, then a resource plane of the new LSP is applied, the old LSP having the ability to support the separation of the signalling plane and the resource plane. The above technical solution can improve the restoration and reestablishment efficiency of the tunnel, can determine the application of resources, and will not cause data flow loss if it is not possible to first establish and then dismantle the MBB.

Description

Method and network element for tunnel reconstruction

Technical field

The present invention relates to the field of communications, and in particular, to a method and a network element for multi-protocol label switching-traffic engineering (MPLS-TE, Multi-Protocol Label Switching-Traffic Engineering) tunnel † grey reconstruction.

Background technique

The traffic engineering (TE, Traffic Engineering) label switching path (LSP) is created by using the RS VP-TE (Resource Reservation Protocol-TE) signaling protocol. The object parameters in the signaling are extracted to create a resource control plane of the TE tunnel.

As shown in Figure 1, the signaling plane in the TE LSP uses the Path State Block (PSB) to indicate the LSP. The removal of the PSB will result in the release of resources such as labels and bandwidth on the LSP resource control plane.

An optimized rerouting method for TE tunnels is described in RFC 3209, which is called Make-Before-Break. However, when the tunnel is restored and rebuilt, it is often necessary to first dismantle and release the old resources before attempting to establish and reserve new path resources. As shown in Figure 2, the traditional tunnel recovery and reconstruction method first removes the old LSP (tunnell:lspl) through the pathtear message and then creates a new LSP (tunnel l:lsp2).

Due to the complexity and uncertainty of the network traffic, when the resource control plane of the old LSP releases the bandwidth resources, the resources occupied by the tunnel (the tunnel) do not exist anymore. When the new LSP passes through the node that coincides with the old LSP. When the physical interface is used, there is uncertainty when applying for resources again. It is possible that physical interface bandwidth resources are applied by other tunnels.

At the same time, due to the requirements of network robustness, it is hoped that a tunnel can perform tunnel recovery and reconstruction as quickly as possible. If the MBB cannot be implemented, first removing the resource control plane of the old LSP will undoubtedly cause some data streams to be lost. Summary of the invention

The technical problem to be solved by the present invention is to provide a tunnel reconstruction method and a network element, which can improve the efficiency of tunnel restoration and reconstruction.

In order to solve the above technical problems, the present invention uses the following technical solutions:

A method of tunnel reconstruction includes:

After the node in the tunnel label switching path (LSP) receives the first path message, in the process of creating the path state control block of the new LSP, if the path state control block of the old LSP in the same tunnel is found, the new LSP is applied. The resource plane, the old LSP has the ability to support the separation of the signaling plane from the resource plane.

The resource field of the current LSP needs to replace the resource plane of the associated LSP in the same tunnel.

The first path message also carries an association object that records the old LSP identifier, and the node searches for the path state control block of the old LSP according to the old LSP identifier.

The step of the node requesting the resource plane of the new LSP includes:

The node reserves the resource plane required for the new LSP from the resource plane that has been applied for by the old LSP. If the resource plane that has been applied for by the old LSP remains, the remaining resource plane is released.

The method also includes:

After the resource plane required for the new LSP is reserved, the path state control block of the old LSP is set to indicate that the signaling plane has been separated from the resource plane.

The method also includes:

After receiving the second path message, the node marks the path state control block of the corresponding LSP according to the indication of the second path message, indicating that the path state control block has the capability of supporting the separation of the signaling plane from the resource plane. The reserved field of the management state object carried by the second path message is set with a bit, indicating that the current LSP has the capability of resource plane separation control.

The method also includes:

After receiving the path removal message, the node checks the corresponding path state control block setting. If the identifier indicating that the signaling plane has been separated from the resource plane is removed, the signaling plane corresponding to the path state control block is removed. If the corresponding path state control block is not set, the identifier indicating that the signaling plane is separated from the resource plane is not set. Then, the signaling plane corresponding to the path state control block is removed, and the resource plane corresponding to the path state control block is released.

A network element, as a node in a tunnel label switching path (LSP), includes a creating module and a resource processing module, where:

The creating module is configured to: after receiving the first path message, create a path state control block of the new LSP;

The resource processing module is configured to: apply for a resource plane of a new LSP, if the path state control block of the old LSP in the same tunnel is found in the process of creating the path state control block of the new LSP, The old LSP has the ability to support the separation of the signaling plane from the resource plane.

The resource processing module is configured to apply for the resource plane of the new LSP according to the following manner: Reserve the resource plane required for the new LSP from the resource plane that has been applied for by the old LSP, and if the reserved resource of the old LSP has been reserved If there is a remaining plane, the remaining resource planes are released.

The resource processing module is further configured to:

The network element further includes a marking module, wherein:

The marking module is configured to: after receiving the second path message, mark the path state control block of the corresponding LSP according to the indication of the second path message, indicating that the path state control block supports the separation of the signaling plane from the resource plane The capability, where the reserved field of the management state object carried by the second path message is set with a bit, indicating that the current LSP has the capability of resource plane separation control.

The resource processing module is further configured to: after receiving the path removal message, if the corresponding path state control block is set to indicate that the signaling plane is separated from the resource plane, only the path state control block is removed. If the corresponding path state control block is not set to indicate that the signaling plane has been separated from the resource plane, the signaling plane corresponding to the path state control block is removed, and the corresponding path state control block is released. Resource plane. In summary, the present invention provides a tunnel reconstruction method and a network element, which can improve the efficiency of tunnel restoration and reconstruction, and can determine the application to the resource. If the MBB cannot be implemented, the data stream will not be lost. BRIEF abstract

1 is a schematic diagram of a relationship between a signaling plane and a resource plane;

2 is a schematic diagram of a conventional tunnel recovery and reconstruction mode;

3 is a schematic diagram of a network element according to an embodiment of the present invention;

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

FIG. 5 is a flowchart of a method for tunnel reconstruction according to an application example of the present invention.

Preferred embodiment of the invention

In order to make the objects, the technical solutions and the advantages of the present invention more clearly, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments of the present application may be arbitrarily combined with each other. These combinations are all within the scope of the invention.

FIG. 3 is a schematic diagram of a network element according to an embodiment of the present invention. As shown in FIG. 3, when the network element in this embodiment is used as a node in a tunnel LSP, the method includes a creation module and a resource processing module, where:

The resource processing module is configured to: apply for a resource plane of a new LSP, if the path state control block of the old LSP in the same tunnel is found in the process of creating the path state control block of the new LSP, The old LSP supports the ability of the signaling plane to be separated from the resource plane.

The resource processing module is configured to apply for the resource plane of the new LSP according to the following manner: Reserve the resource plane required for the new LSP from the resource plane that has been applied for by the old LSP, and if the reserved resource of the old LSP has been reserved If there is a remaining plane, the remaining resource planes are released. The resource processing module is further configured to: after the resource plane required for the new LSP is reserved, set the identifier indicating that the signaling plane is separated from the resource plane to the path state control block of the old LSP.

The resource processing module may be further configured to: after receiving the path removal message, if the corresponding path state control block is set to indicate that the signaling plane has been separated from the resource plane, only the path state control block is removed. Corresponding signaling plane; if it is detected that the corresponding path state control block is not set to indicate that the signaling plane has been separated from the resource plane, the signaling plane corresponding to the path state control block is removed, and the path state control block is released Resource plane.

The network element of this embodiment may further include a marking module, where:

The marking module is configured to: after receiving the second path message, mark the path state control block of the corresponding LSP according to the indication of the second path message, indicating that the path state control block has a separation of the supporting signaling plane and the resource plane. The capability, where the reserved field of the management state object carried by the second path message defines a bit, indicating that the current LSP has the capability of resource plane separation control.

FIG. 4 is a flowchart of a method for tunnel reconstruction according to an embodiment of the present invention. As shown in FIG. 4, the method in this embodiment includes the following steps:

S10. After receiving the first path message, the node in the tunnel LSP creates a path state control block of the new LSP.

S20: In the process of creating a path state control block of the new LSP, if the path state control block of the old LSP in the same tunnel is found, the resource plane of the new LSP is applied, and the old LSP supports the signaling plane and the resource plane. Ability. The method for tunnel reconstruction proposed by the embodiment of the present invention, by extending RSVP signaling

The field in the Admin—Status object controls the resource control plane independently.

In this embodiment, the Reserved field of the Admin_Statue object in RSVP signaling is extended in the existing IETF standard, and three new Bit bits are defined.

The extended bit bits are called:

S bit, bit 23, used to indicate that the current LSP has the capability of resource plane separation control;

W bit, 22nd bit, used to indicate that the resource plane of the current LSP is separated from the signaling plane;

The 0 bit, the 21st bit, is used to indicate that the resource plane of the current LSP needs to replace the resource plane of the associated LSP in the same tunnel. You also need to use the Association object to record the identity of the old LSP ( lspld ) in the Path message of the new LSP.

This embodiment includes the following steps:

Step 100: The advertised LSP supports the capability of separating the signaling plane from the resource control plane. The step may include steps 101-104:

Step 101: The first node of the tunnel carries the Admin_Status object with the S bit set in the sent Path message, and the downstream node of the LSP is notified that the signaling plane is separated from the resource control plane.

Step 102: After receiving the Path message with the S bit set, each node in the LSP records the flag in the PSB, indicating that the local LSP node supports the separation control between the signaling plane and the resource control plane.

Step 103: The Resv message of the LSP also needs to carry the Admin_Status object with the S bit set. If the Resv message includes the S bit, but the local PSB does not contain the S bit flag, the Resv message is discarded, and Send a PathErr (path error) message to the first node of the tunnel;

Step 104: After the tunnel first node receives the Resv message containing the S bit, the entire node may be considered

The LSP has the ability to separate the signaling plane from the resource plane.

Step 200: Create a new LSP, and separate the signaling plane of the old LSP from the resource plane. The step may include Step 201 - Step 205, as shown in FIG. 5:

Step 201: When the first node of the tunnel resumes rebuilding a tunnel without using MBB, the first node first sends a new Path message, which carries the Admin-Status object of 0 bits and carries Recording the association object of the lspld of the old LSP; Step 202: After receiving the Path message containing 0 bits, the node in the LSP path needs to find the old PSB to be replaced according to the lspld in the Association object while creating a new PSB; If the old PSB cannot be found, it indicates that the new LSP has passed the node that the old LSP has not passed, and the new PSB applies for its own resource plane.

If the S-bit flag set in the middle of the old PSB is found, it indicates that the resource plane of the old PSB is allowed to be separated from the signaling plane. In this case, the current node can release the old LSP while reserving the resource plane of the new LSP. Resource plane, and set the forwarding of the new LSP to be valid. Users can customize the strategy of resource replacement;

For example, policy 1: The new LSP applies for the resource plane itself, and is not reserved from the resource plane of the old LSP.

Policy 2: The resource plane of the new LSP must be reserved from the resource plane of the old LSP. If the resource plane of the old LSP is insufficient, the new LSP is considered to be failed. The reason for the failure is that the required resources cannot be reserved.

If the old PSB is found but the S bit is not set, the new PSB also applies for its own resource plane.

After confirming that the resource plane of the old LSP has been released, the S bit of the PSB corresponding to the old LSP is reset, and the W bit is set, indicating that the signaling plane is separated from the resource plane.

Step 203: The Resv message of the new LSP carries the S and 0 bits, resets the 0 bits in each node PSB along the way, and resets the S bit.

Step 204: After receiving the Resv message containing 0 bits, the first node of the tunnel considers that the new LSP has completed the resource establishment, and the resource plane of the old LSP has been released. At this time, the first node may send a Pathtear message to tear down the old LSP. Plane

Step 205: After receiving the PathTear message, each node in the LSP searches for the corresponding PSB, and checks whether the corresponding PSB has the W bit set. If yes, only the signaling plane is removed, and the resources of the resource plane are not released; If the WB is not set to the WB, the old LSP has a node where the new LSP does not pass. The resource plane of the old LSP still exists. At this time, the signaling plane needs to be released and the resource plane needs to be released.

In a preferred embodiment, the resource plane of the new LSP may be preferentially requested from the resource plane of the old LSP, and then the remaining resources of the old LSP are released, and the S bits of the old PSB are reset, and the W bit is set, indicating that the old PSB only retains the letter. Order status.

Compared with the prior art, the present invention is used to add a control separation technology between a signaling plane and a resource plane in a TE tunnel. The resource release of the resource plane is no longer completely dependent on the removal of the signaling plane status block, and can be independently released. The specific advantages are reflected in: 1. Don't worry about the bandwidth of the tunnel after the old LSP is removed from the traditional tunnel. The interface can recover the uncertainty when the new LSP is created. When each node can set a different resource replacement policy, the resources of the old LSP can be directly preempted and released by the new LSP, that is, the new LSP can obtain the same bandwidth, label, and the like as the old LSP.

2. The time for the restoration and reconstruction of the tunnel is improved. The reconstruction of the traditional tunnel needs to wait for the old LSP to completely remove the resource plane before the new LSP is created. The method provided by the present invention can create a new LSP and directly replace the old LSP resource plane. The data forwarding plane is valid. If the new LSP is created successfully, the tunnel is restored. The removal of the old LSP signaling plane does not affect the recovery time of the entire tunnel.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program instructing 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 may be implemented in the form of hardware or in the form of a software function module. 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. Corresponding changes and modifications are intended to be included within the scope of the appended claims.

Industrial applicability

In summary, the present invention provides a tunnel reconstruction method and a network element, which can improve the efficiency of tunnel restoration and reconstruction, and can determine the application to the resource. If the MBB cannot be achieved, the data stream will not be lost. Therefore, the present invention has strong industrial applicability.

Claims

Claim

1. A method of tunnel reconstruction, comprising:

2. The method of claim 1 wherein:

A reserved bit is set in the reserved field of the management state object carried in the first path message, indicating that the resource plane of the current LSP needs to replace the resource plane of the associated LSP in the same tunnel.

3. The method of claim 2, wherein:

The first path message also carries an association object that records an old LSP identifier, and the node searches for a path state control block of the old LSP according to the old LSP identifier.

4. The method of claim 1, wherein: the step of the node requesting a resource plane of a new LSP comprises:

5. The method of claim 4, further comprising:

6. The method of any of claims 1-5, further comprising:

7. The method of any of claims 1-5, further comprising:

After receiving the path removal message, if the node detects that the corresponding path state control block is set to indicate that the signaling plane has been separated from the resource plane, the node only removes the path state control block pair. If the corresponding path state control block is not set to indicate that the signaling plane has been separated from the resource plane, the signaling plane corresponding to the path state control block is removed, and the path state control block is released. Resource plane.

8. A network element, as a node in a tunnel label switching path (LSP), includes a creating module and a resource processing module, where:

The network element according to claim 8, wherein the resource processing module is configured to apply for a resource plane of a new LSP according to the following manner:

The resource plane required for the new LSP is reserved from the resource plane that has been applied for by the old LSP. If the resource plane that has been applied for by the old LSP remains, the remaining resource plane is released.

The network element according to claim 9, wherein the resource processing module is further configured to: after the resource plane required for the new LSP is reserved, setting the path state control block of the old LSP to indicate that the signaling plane has been associated with the resource The logo of the plane separation.

The network element according to any one of claims 8 to 10, further comprising a marking module, wherein: the marking module is configured to: after receiving the second path message, according to the second path message And indicating that the path state control block of the corresponding LSP is marked, indicating that the path state control block supports the capability of separating the signaling plane from the resource plane, where the reserved field of the management state object carried by the second path message is set The bit indicates that the current LSP has the capability of resource plane separation control.

12. The network element of any of claims 8-10, wherein:

The resource processing module is further configured to: after receiving the path removal message, if the corresponding path state control block is set to indicate that the signaling plane has been separated from the resource plane, only the letter corresponding to the path state control block is removed. If the corresponding path state control block is not set to indicate that the signaling plane has been separated from the resource plane, the corresponding path state control block is removed. The signaling plane releases the resource plane corresponding to the path state control block at the same time.