WO2011157130A2

WO2011157130A2 - Path establishment method and apparatus

Info

Publication number: WO2011157130A2
Application number: PCT/CN2011/074983
Authority: WO
Inventors: 章发太; 林毅; 资小兵
Original assignee: 华为技术有限公司
Priority date: 2011-05-31
Filing date: 2011-05-31
Publication date: 2011-12-22
Also published as: CN102204190A; WO2011157130A3; CN102204190B

Abstract

The embodiments of the present invention disclose a path establishment method and apparatus. The method includes the following steps: calculating a section protection path for a leaf node needing protection, or calculating a section restoration path for a leaf node needing restoration; sending a path message to the first node of the section protection path or the section restoration path, so as to make the first node of the section protection path or the section restoration path to send the path message along the section protection path or the section restoration path to each node on the path, and establishing the section protection path or the section restoration path according to the path message. The apparatus includes a calculation module and an establishment module. The embodiments improve the utilization rate of the network resource.

Description

Path establishment method and device

Technical field

The embodiments of the present invention relate to communication technologies, and in particular, to a path establishment method and apparatus. Background technique

Point to Mul t i-Point (hereinafter referred to as P2MP) Multicast technology is a transmission technology that transmits services from a single sender to multiple receivers. It is first applied to IP networks. As people's demand for communication has become higher and higher, the demand for large bandwidth multicast services such as video conferencing, video on demand, and multi-party data block backup has begun to emerge.

To support these types of multicast services, a P2MP multicast tree needs to be established and maintained in the transport network. The multicast tree refers to a single fixed source bandwidth between a source network element and multiple sink network elements in the transport network. To the tree connection. When conducting business on the transport network, ensuring the survivability of the service becomes a very important issue. The mechanisms for ensuring survivability include the protection mechanism and the recovery mechanism (Res torat ion). The protection mechanism refers to establishing a protection path for the protected connection before the failure occurs. After the failure occurs, the service needs to be switched to the protection path. The recovery mechanism refers to the use of resources in the network after the failure occurs. Establish a new path to deliver the business affected by the failure. When the P2MP service is deployed on the transport network, the survivability of the P2MP connection must be ensured to ensure that the P2MP service can still be transmitted after the outgoing network fault occurs.

In the prior art, the section protection scheme is generally only applied to a Point to Point (P2P) type label switching path (hereinafter referred to as LSP), if the P2MP connection is to be viewed. For multiple source-to-leaf (S2L) sub-label switching paths (sub-LSPs), the existing P2P segment protection scheme can also be applied to P2MP. First, assign a P2MP identifier (Ident if ier; hereinafter referred to as ID) and an LSP ID to the P2MP working LSP, and establish a working LSP of the P2MP; select branch nodes and merge on each S2L sub-LSP of the P2MP. a merge node where the branch node and The merged node is the first and last nodes of the segment to be protected on the LSP respectively. For example, if the LSP passes through the node ABCDE, if the segment BCD needs to be protected (for example, the segment protection path BXYZD is established), the node B is a branch node. Node D is a merged node. A protection LSP separated from the S2L sub-LSP is calculated between the branch node and the merged node on each S2L sub-LSP. The LSP ID is assigned to each protection LSP. LSP and associate the protection LSP with the corresponding S2L sub-LSP.

However, in the prior art, at least the following drawbacks exist: In the prior art, a section protection path or a section recovery path cannot be established across different S 2 L s ub-LSPs, and thus the utilization of network resources is low. Summary of the invention

The embodiments of the present invention provide a path establishment method and device, which are used to establish a section protection path or a section recovery path across different S2L sub-LSPs, thereby improving network resource utilization.

In order to achieve the above object, an embodiment of the present invention provides a path establishment method, including: calculating a section protection path for a leaf node that needs to be protected, or calculating a section restoration path for a leaf node that needs to be restored; The first node of the protection path is a node other than the leaf node to be protected on the point-to-multipoint P2MP multicast tree, and has the shortest path or minimum cost from the head node to the leaf node, the section recovery path The first node is a node on the P2MP multicast tree except the leaf node that needs to be restored, and has the shortest path or minimum cost from the head node to the leaf node;

Transmitting a path message to a head node of the section protection path or the recovery path of the section, such that the section protection path or a head node of the section restoration path along the section protection path or the area The segment recovery path sends the path message to each node on the path, and establishes the segment protection path or the segment recovery path according to the path message.

The embodiment of the invention provides a path establishing device, including:

a calculation module, configured to calculate a segment protection path for a leaf node that needs to be protected, or calculate a segment recovery path for a leaf node that needs to be restored; where the first node of the segment protection path is a point A node other than the leaf node to be protected on the multi-point P2MP multicast tree, and having the shortest path or minimum cost from the head node to the leaf node, the first node of the section recovery path being P2MP multicast a node on the tree other than the leaf node that needs to be restored, and having the shortest path or minimum cost from the head node to the leaf node;

Establishing a module, configured to send a path message to the first node of the section protection path or the section recovery path, so that the section protection path or the first node of the section recovery path is protected along the section The path or the section recovery path transmits the path message to each node on the path, and the section protection path or the section restoration path is established according to the path message.

The method and device for establishing a path according to the embodiment of the present invention, the source node of the P2MP multicast tree is used to calculate the section protection path for the leaf node to be protected, or the section recovery path is calculated for the leaf node that needs to be restored, and the section is selected. The first node of the protection path or the section recovery path is a node other than the leaf node, and the first node to the leaf node has the shortest path or the least cost, and then the source node sends a path message to the first node, and the first node is further along the area The segment protection path or the segment recovery path sends a path message to each node on the path, so that each node establishes the segment protection path or the segment recovery path according to the path message. This embodiment can implement different S 2L sub-LSPs. Establish a zone protection path or a zone recovery path to improve the utilization of network resources. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description of the drawings used in the embodiments or the prior art description will be briefly described below. Obviously, the drawings in the following description It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any inventive labor.

1 is a flowchart of Embodiment 1 of a path establishment method according to the present invention;

2 is a flowchart of Embodiment 2 of a path establishment method according to the present invention;

3 is a schematic structural diagram of a P2MP multicast tree in Embodiment 2 of a path establishment method according to the present invention; FIG. 4 is a flowchart of Embodiment 3 of a path establishment method according to the present invention; FIG. 5 is a structural diagram of Embodiment 1 of a path establishing apparatus according to the present invention; FIG.

FIG. 6 is a structural diagram of Embodiment 2 of the path establishing apparatus of the present invention. detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is a partial embodiment of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

FIG. 1 is a flowchart of a method for establishing a path according to a first embodiment of the present invention. As shown in FIG. 1 , this embodiment provides a path establishment method, which may specifically include the following steps:

Step 101: The source node of the P2MP multicast tree calculates a section protection path for the leaf node to be protected, or calculates a section recovery path for the leaf node that needs to be restored.

In this embodiment, the source node of the P2MP multicast tree calculates the zone protection path for the leaf node to be protected in the multicast tree, or calculates the zone recovery path for the leaf node that needs to be restored. The zone protection path is a protection path established for the protected connection before the fault occurs, and can be established simultaneously with the P2MP working LSP. After the fault occurs, only the service is switched to the section protection path, and the section recovery path is needed. A path calculated and established to utilize resources in the network after a failure occurs. In this embodiment, when the source node calculates the segment protection path or the segment recovery path for the leaf node, the first node of the selected segment protection path is a node other than the leaf node to be protected, and from the node The first node to the leaf node has the shortest path or minimum cost; the first node of the selected segment recovery path is a node other than the leaf node that needs to be restored, and has the shortest path or minimum cost from the first node to the leaf node. Specifically, when calculating the section protection path, the source node selects a node other than the protected leaf node as the first node of the section protection path on the P2MP working LSP, so that the shortest path is from the head node to the leaf node. Or the cost is the smallest, and the protection path of the section is separated from the S2L sub-LSP where the leaf node is located. When calculating the segment recovery path, the source node is working at P2MP Selecting a node other than the protected leaf node as the first node of the segment recovery path on the LSP, the first node is a node that is not affected by the fault, so that the shortest path or the cost is the highest from the first node to the leaf node. And the zone recovery path can bypass the failed link and/or node.

Step 102: The source node sends a path message to the first node of the section protection path or the section recovery path, so that the first node of the section protection path or the section recovery path is along the section protection path or the section recovery path to the path. Each node sends a path message and establishes a zone protection path or a zone recovery path according to the path message.

After the source node calculates the segment protection path for the leaf node to be protected, or calculates the segment recovery path for the leaf node that needs to be restored, the source node sends a path to the segment protection path or the first node of the segment recovery path ( The Path message, after receiving the Path message, the first node sends the Path message along the segment protection path or the segment recovery path to each node on the path. Therefore, after receiving the Path message, each node on the segment protection path or the segment recovery path can establish a segment protection path or a segment recovery path according to the Path message. Specifically, the intermediate node and the last node on the segment protection path or the segment recovery path may reserve bandwidth resources on the segment protection path or the segment recovery path according to the Path message and establish a cross-connection in the data plane thereof. The first node of the protection path or the zone recovery path establishes a branch cross-connection to the direction of the intermediate node. The leaf node can automatically associate the working branch with the zone protection path or the zone recovery path according to the Path message.

This embodiment provides a path establishment method, where a source node of a P2MP multicast tree calculates a section protection path for a leaf node to be protected, or a section recovery path of a leaf node that needs to be restored, and selects a section protection path or The first node of the segment recovery path is a node other than the leaf node, and the first node to the leaf node has the shortest path or the least cost, and then the source node sends a path message to the first node, and the first node further follows the segment protection path. Or the segment recovery path sends a path message to each node on the path, so that each node establishes the segment protection path or the segment recovery path according to the path message. This embodiment can implement segment protection across different S2L sub-LSPs. The path or zone recovery path also improves the utilization of network resources. 2 is a flowchart of Embodiment 2 of a path establishment method according to the present invention. As shown in FIG. 1 , this embodiment provides a path establishment method, and this embodiment is specifically a process of establishing a section protection path, and FIG. 3 is a process of the present invention. A schematic diagram of the structure of the P2MP multicast tree in the second embodiment of the path establishment method. As shown in FIG. 3, it is assumed that in the transport network, a P2MP multicast tree from the source node S to the three leaf nodes D1, D2, and D3 is required to be established, and It is required to provide a segment protection for the leaf node D2, that is, a segment protection path is established for the D2, and a method for establishing a segment protection path for the leaf nodes D1 and D3 is similar. Here, only D2 is taken as an example for description. This embodiment may specifically include the following steps:

Step 201: The source node of the P2MP multicast tree calculates a P2MP working LSP.

In this step, the P2MP working LSP is calculated for the source node of the P2MP multicast tree. This step can be implemented by using the existing working path calculation method. The calculated P2MP working LSP can be as shown in Figure 3. That is, three S2L sub-LSPs including SB-D1, SB-D2, and SD-D3.

Step 202: The source node calculates a section protection path for the leaf node that needs to be protected.

The leaf node to be protected in this embodiment takes the node D2 in FIG. 3 as an example, the source node S calculates the segment protection path for the leaf node D2, and the source node can select the first node of the segment protection path as the P2MP connection except D2. Any node other than the node, and the last node is D2, and the segment protection path is a path separated from the S2L sub-LSP (ie, SB-D2) where the leaf node D2 is located. Specifically, when calculating the section protection path, the source node may select a node other than the protected D2 as the first node of the section protection path on the P2MP working LSP, so that the shortest path from the head node to D2 or The least cost. As shown in FIG. 3, the source node may select the node B or D as the first node of the segment protection path. Of course, other nodes may also be selected as the source node. Here, only the node B or D is taken as an example, but The section protection path DF-D2 is better than the section protection path BC-D2, so the node D is finally selected as the head node of the section protection path.

Step 203: The source node sends a Path message hop by hop to each node in the path along each S2L sub-LSP and the section protection path.

In this embodiment, the section protection path DF-D2 is a special branch of the P2MP multicast tree, rather than an independent LSP, so there is no need to separately allocate the LSP ID for the section protection path. This step The P2MP source node allocates a P2MP ID and an LSP ID to the P2MP multicast tree as the identifier of the P2MP working LSP. The source node sends a Path message along each branch of the multicast tree, that is, the source node along each S2L. The sub-LSP and the zone protection path send Path messages to each node in the path. In this embodiment, the source node may send a Path message by using a multi-path scheme or a single-path scheme, where the multi-path scheme means that the source node sends different Path messages for each S2L sub-LSP and the section protection path respectively. A single Path scheme means that the source node sends only the same Path message to each downstream node. Of course, a plurality of S2L sub-LSPs may be established by using a single path scheme, and other S2L sub-LSPs may be established by using a multi-path scheme.

Specifically, for the multi-path solution, the Path message sent by the source node carries the source node address, the P2MP ID, the LSP ID, the explicit routing information, and the protection recovery type of the P2MP multicast tree, where each Path message carries The display routing information and protection recovery type are different. For the S2L sub-LSP, the explicit routing information in the Path message can be explicitly routed through the object (Expl i ci t Route Objec t; hereinafter referred to as: ER0) or the second explicit route object (Second Expl ic it Route) Object (hereinafter referred to as SERO) specifies the path information of the S2L sub-LSP. For example, the explicit routing information of the leaf node D1 in FIG. 3 can be expressed as ER0={S, B, D1}. The Path message may also carry the protection recovery type. The protection recovery type indicates that the S2L sub-LSP is the working path. Of course, those skilled in the art may understand that the Path message may not carry the protection recovery type. At this time, the S2L sub-LSP is the working path by default. For the segment protection path, the explicit routing information in the Path message can also specify the path information of the protection path of the segment through ER0 or SER0. The explicit routing information of D2 in Figure 3 can be expressed as ER0= { D, F, D2}. In addition, the protection recovery type needs to be specified in the Path message. The protection recovery type in this embodiment may be a segment 1+1 protection, a segment 1: 1 protection, or a segment preset protection, and for the segment 1: In terms of protection, it is further possible to specify in the Path message whether the section protection path allows the bearer to be preempted for additional services when the working path is normal.

For a single-path scheme, the Path message sent by the source node carries the source node address, P2MP ID, LSP ID, explicit routing information, and protection recovery type of the P2MP multicast tree. For S2L sub-LSP The explicit routing information in the Path message can be specifically passed through the ER0 in the resource re-provisioning protocol (RSVP-TE) signaling protocol. The second explicit routing object (Secondary Exploratory Route Object; hereinafter referred to as SERO) specifies the path information of the S2L sub-LSPP2MP multicast tree, and the information implies each S2L sub-LSP in the P2MP multicast tree. Path information. For example, the multicast tree in Figure 3 can be expressed as ER0= {S, B, Dl}, SER0= {B, D2}, SER0= {S, D, D3}, which implies the P2MP group. Path information of three S2L sub-LSPs included in the broadcast tree: SB-D1, SB-D2, and SD-D3. For the segment protection path, the explicit routing information in the Path message can also specify the path information of the protection path of the segment through ER0 or SERO. The explicit routing information of D2 in Figure 3 can be expressed as SER0= { D, F, D2}. In order to distinguish from the SER0 of the working branch, it is necessary to add an identifier to the SER0 of the section protection path, indicating that the SER0 is a section protection path instead of a working branch. In addition, the protection recovery type needs to be specified in the Path message. The protection recovery type in this embodiment may be a segment 1+1 protection, a segment 1: 1 protection, or a segment preset protection, and for the segment 1: In terms of protection, it is further possible to specify in the Path message whether the section protection path allows the bearer to be preempted for additional services when the working path is normal.

In this embodiment, the format of the SERO object is as follows:

Length (bytes) | Class-Num | C_Type I

II (sub-Object) II where Length represents the length of the SERO object (unit: byte), and Class-Num (Class Number ) represents the object number of the object, such as Class-Num=200, C-Type ( Class Type ) Indicates the object type of the object, such as C-Type=2, and the sub-Object part contains multiple sub-objects for describing explicit routing information. For example, the address of each node or each link or each port through which the P2MP branch passes may be filled in the sub-Object in order to indicate the route of the branch. In this embodiment, the sub-Object can also be filled with a protected recovery type sub-object, and its format is as follows:

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + L Type | Length | Reserved

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+

S I P Reserved | LSP Flags | Reserved

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+ where 3 fields such as L, Type, and Length are the common headers of the child object, and L indicates whether the explicit route object is a strict route or a loose route. In the invention, the bit is not needed for the protection recovery type sub-object; Type indicates the type of the sub-object; Length indicates the length of the sub-object. The other fields are the contents of the protected recovery type sub-objects, as follows:

S: =1 means that resources are reserved only in the control plane when the branch is established, and no cross-connection is established in the data plane; =0 indicates that resources are reserved in the control plane when the branch is established, and cross-connection is established in the data plane. For example, in the present invention, if it is necessary to establish a section preset protection branch, S=l can be set.

P: =1 indicates that the branch is a protection branch, and =0 indicates that the branch is a working branch. In this embodiment, for a segment 1+1 protection branch or a segment 1:1 protection branch, the value of P is 1.

LSP Flags indicates the type of protection recovery for this branch. For example: "0x01" means the zone recovery path, "0x02" means zone preset protection, "0x04" means zone 1:1 protection, and "0x08" means zone 1+1 protection.

Step 204: Each node on each S2L sub-LSP establishes a P2MP working LSP according to the Path message. After the Path message is received, each node on each S2L sub-LSP establishes a P2MP working LSP according to the Path message. The existing P2MP working path establishment method may be used, and the P2MP information is saved in the control plane. For example, the source node address, P2MP ID, and LSP ID of the P2MP multicast tree are not mentioned here.

Step 205: Each node on the zone protection path establishes a zone protection path according to the Path message. After receiving the Path message from the source node, the first node D of the segment protection path learns that the segment protection path of the DF-D2 needs to be established according to the explicit routing information and the protection recovery type carried in the Path message. The first node D sends a Path message to each node in the path hop by hop along the segment protection path DF-D2 (for example, the node D sends a Path message to the node F, and the node F processes the Path message locally and sends it to the node D2. The local processing here may be to save the information in the Path message locally, and the section protection path is established according to the Path message, where the Path message is used. The different types of protection recovery carried are used to illustrate the specific path establishment process.

When the protection recovery type is the segment 1+1 protection, the first node D of the segment protection path sends a Path message to each node in the path along the segment protection path DF-D2, where the Path message carries the source of the P2MP multicast tree. Node address, P2MP ID, LSP ID, ERO information, and protection recovery type. The first node can reassign the LSP ID, or directly adopt the LSP ID assigned by the source node. The ERO or SERO information includes the path information of the segment protection path. -D2. After receiving the Path message, the intermediate node F and the last node D2 respectively reserve bandwidth resources on the links DF and F-D2, and establish cross-connections in the data plane, and return reservations (Resv) to the respective upstream nodes. Message, thereby establishing a zone protection path. After that, the first node D also creates a branch cross-connection to the F direction of the intermediate node.

When the protection recovery type is the section 1:1 protection, the first node D of the section protection path sends a Path message to each node in the path along the section protection path DF-D2, where the Path message carries the source of the P2MP multicast tree. Node address, P2MP ID, LSP ID, ERO information, and protection recovery type. The first node can reassign the LSP ID, or directly adopt the LSP ID assigned by the source node. The ERO or SERO information includes the path information of the segment protection path. -D2. After receiving the Path message, the intermediate node F and the last node D2 respectively reserve bandwidth resources on the links DF and F-D2, establish cross-connections in the data plane, and return Resv messages to the respective upstream nodes, thereby establishing Zone protection path. The protection attribute may also be carried in the Path message. If the protection attribute of the section protection path DF-D2 is specified to allow additional services to be carried, the established section protection path DF-D2 may also be used to transmit other extra preemptibles. business.

When the protection recovery type is the segment preset protection, the first node D of the segment protection path sends a Path message to each node in the path along the segment protection path DF-D2, where the Path message carries the source node of the P2MP multicast tree. The address, the P2MP ID, the LSP ID, the ERO information, and the protection recovery type, where the first node can reassign the LSP ID, or directly adopt the LSP ID assigned by the source node, and the ERO or SERO information includes the path information DF of the segment protection path. D2. After receiving the Path message, the intermediate node F and the last node D2 reserve bandwidth resources only on the link DF and the F-D2, respectively. A Resv message is returned to the respective upstream node to establish a zone protection path.

Step 206: The leaf node automatically associates the segment protection path and the corresponding S2L sub-LSP according to the received Path message.

After the leaf node D2 receives the two Path messages from the P2MP working LSP and the segment protection path respectively, the leaf node D2 can learn the two Path messages according to the source node address and the P2MP ID of the P2MP multicast tree carried in the Path message. The same P2MP service can be used to establish a working branch according to the protection type of the two Path messages. Which Path message is used to establish the protection path, the leaf node can use the Path message. Automatically associate the working branch with the section protection path, ie automatically associate the section protection path with the corresponding S2L sub-LSP

Step 207: When the leaf node cannot receive the service data from the P2MP working LSP due to the network failure, the service on the failed S2L sub-LSP is selected on the segment protection path.

After the calculation and establishment of the section protection path are completed through the above steps, the section protection path can be utilized to perform protection switching of the service. If the leaf node D2 cannot receive service data from the P2MP working LSP due to network failure, for example, a link fault occurs on the working branch B-D2, or the node B fails, then the pair may appear on the associated segment protection path. The service on the faulty S2L sub-LSP is selected. In this embodiment, when the zone protection path is established, the protection recovery type is different, and the corresponding protection switching process is also different.

When the protection recovery type is the segment 1+1 protection, the node D2 detects that the service data cannot be received on the B-D2 due to the work branch failure, and can directly switch to the associated segment protection path F-D2, The service is selected on the segment 1+1 protection branch F-D2. If it is set to allow return when the zone protection path is established, when the node D2 detects that the failure on the branch B-D2 has disappeared, the service is again selected on the working branch B-D2.

When the protection recovery type is zone 1:1 protection, if the node B detects a failure in the network, it starts from the node B, and determines whether the zone protection branch of the leaf node D2 is downstream of the node, and if so, the zone The first node of the segment protection branch sends a fault notification message; if not, along D2 The S2L sub-LSP (D2-BS) is located in the upstream direction to notify the fault, and the upstream node repeats the above operation until the fault notification message is sent to the source node S of the P2MP multicast tree. In this embodiment, after receiving the fault notification, the source node S determines that the node is the upstream node of the segment protection branch, and sends a switching command to the first node D of the segment protection path, and the first node D establishes a direction to the node F. The branches are cross-connected, so node D2 can select traffic on the zone protection path DF-D2. The fault notification message and the switching command may be an RSVP-TE signaling message of the control plane or an Automatic Protection Switching (APS) message of the data plane.

When the protection recovery type is zone preset protection, if the node B detects that the network is faulty, it starts from the node B, determines whether the zone protection branch of the leaf node D2 is downstream of the node, and if so, protects the zone. The first node of the branch sends a fault notification message; if not, the fault notification message is sent in the upstream direction along the S2L sub-LSP (D2-BS) where D2 is located, and the upstream node repeats the above operation until the fault notification message is sent to the P2MP source. Node S. In this embodiment, after receiving the fault notification message, the source node S determines that the node is the upstream node of the segment protection branch, and sends a switching command to the first node D of the segment protection path, and the node D along the segment protection path DF -D2 sends a Path message, and each node on the request path establishes a cross-connection in the data plane according to the previously reserved resources. After the section protection path is established, a new branch cross-connection to the node F direction is established in the node D, Node D2 can select traffic on the zone protection path DF-D2.

The present embodiment provides a path establishment method, in which a source node of a P2MP multicast tree calculates a zone protection path for a leaf node to be protected, and selects a node of the zone protection path as a node other than the leaf node, and the node The first node to the leaf node has the shortest path or the least cost, and then the source node sends a path message to the first node, and the first node sends a path message along the section protection path to each node on the path, so that each node according to the path message The section protection path is established. In this embodiment, the section protection path is used as a branch of the P2MP working LSP, instead of a new P2P LSP. Therefore, this embodiment only needs to manage one P2MP LSP, which simplifies management. The zone protection path and the P2MP working LSP use the same P2MP ID and LSP ID, both from Dynamic association, no need to associate each section protection path; at the same time, this embodiment can establish a section protection path across different S2L sub-LSPs, thereby establishing a better path and achieving more flexible section protection. It also improves the utilization of network resources.

4 is a flowchart of a third embodiment of a path establishment method according to the present invention. As shown in FIG. 4, this embodiment provides a path establishment method, and the embodiment is specifically a process for establishing a section recovery path, and continues to refer to FIG. 3 above. In the transport network, there is already a P2MP multicast tree from the source node S to the three leaf nodes D1, D2, D3. When the network fault causes the leaf node D2 to fail to receive service data, it needs to establish a section for D2. The recovery path is similar to the method of establishing a section recovery path for the leaf nodes D1 and D3. Here, only D2 is taken as an example for description. The embodiment may include the following steps: Step 401: A source node of a P2MP multicast tree calculates and establishes a P2MP working LSP.

This step is to calculate and establish a P2MP working LSP for the source node of the P2MP multicast tree. This step can be implemented by using the existing working path calculation and establishment method. The calculation of the P2MP working LSP can be as shown in Figure 3. As shown in the figure, including SB-D1, SB-D2, SD-D3, three S2L sub-LSPs

Step 402: When a fault occurs in the network, the faulty upstream node sends a fault notification message to the source node.

This step is a fault notification process. When a fault occurs in the network, assuming that the link B-D2 fails, the faulty upstream node B sends a fault notification message to the source node S.

Step 403: The source node calculates a section recovery path for the leaf node of the failed link. In this embodiment, the faulty link is B-D2, the leaf node of the link is D2, the source node S calculates the section recovery path for the leaf node D2, and the source node can select the first node of the section recovery path as Any node on the P2MP connection that is not affected by the failure, and the last node is D2, and the section recovery path does not pass through the faulty link B-D2. Specifically, when calculating the section recovery path, the source node may select, on the P2MP working LSP, a node other than D2, which is not affected by the fault, as the first node of the section recovery path, so that the node from the head node to the D2 has The shortest path or cost is minimal and does not pass through the faulty link B-D2. As shown in Figure 3, the source node can select node B or D as the zone. The segment restores the first node of the path, but since the segment recovery path DF-D2 is better than the segment protection path BC-D2, the node D is finally selected as the first node of the segment recovery path.

Step 404: The source node sends a Path message to the first node of the path along the section recovery path.

In this embodiment, the section recovery path D-F-D2 is a special branch of the P2MP multicast tree, rather than a separate LSP, so there is no need to separately assign the LSP ID to the section recovery path. In this step, after the segment recovery path DF-D2 of the leaf node D2 is calculated, the source node S sends a Path message to the first node D of the segment recovery path, and carries the source of the P 2MP multicast tree in the Path message. Node address, P2MP ID, LSP ID, explicit routing information, and protection recovery type. In this embodiment, the explicit routing information in the Path message may specifically specify the path information of the section recovery path by using ER0 or SER0. For example, the explicit routing information of the leaf node D2 in FIG. 3 may be expressed as ER0={ D, F, D3}. In order to distinguish from the SER0 of the working branch, it is necessary to add an identifier to the SER0 of the section recovery path, indicating that the SER0 is a section recovery path rather than a working branch.

Step 405: The first node establishes a section recovery path according to the Path message.

After receiving the Path message, the first node sends a Path message along the section recovery path DF-D2, where the Path message carries the source node address, P2MP ID, LSP ID, explicit routing information of the P2MP multicast tree. Protection recovery type, where the first node can reassign the LSP ID, or directly adopt the LSP ID assigned by the source node. After receiving the Path message, the intermediate node F and the last node D2 respectively on the link DF and F-D2. The bandwidth resources are reserved, and a cross-connection is established in the data plane, and a Resv message is returned to the respective upstream nodes, thereby establishing a section recovery path. After that, the first node D also creates a new branch cross-connection to the intermediate node F direction.

Step 406: The leaf node automatically associates the section recovery path with the faulty working branch according to the received Path message, and performs service switching.

After the leaf node D2 receives the Path message from the segment recovery path, it can learn from the P2MP information saved by itself and the source node address, P2MP ID, LSP ID, and protection recovery type of the P2MP multicast tree carried in the Path message. The Path message is used to establish a section recovery path, and the leaf node can automatically associate the working branch with the section recovery path according to the Path message, that is, The zone is automatically associated with the zone recovery path and the corresponding S2L sub-LSP, and the service is selected on the zone recovery path DF-D2.

This embodiment provides a path establishment method, where a source node of a P2MP multicast tree calculates a section recovery path for a leaf node that needs to be restored, and the first node of the section recovery path is selected except a leaf node and is not affected by the fault. a node, and the first node to the leaf node has the shortest path or the least cost, and then the source node sends a path message to the first node, and the first node sends a path message to each node on the path along the section recovery path, The node establishes the section recovery path according to the path message. In this embodiment, the section recovery path is used as a branch of the P2MP working LSP, instead of a new P2P LSP. Therefore, this embodiment only needs to manage one P2MP LSP, which simplifies management. And the section recovery path and the P2MP working LSP in this embodiment use the same P2MP ID and LSP ID, and the two are automatically associated, and the association path of each section is not required to be associated; The S2L sub-LSP establishes a section recovery path to establish a better path and implement a more flexible section recovery. , But also improve the utilization of network resources.

A person skilled in the art can understand that all or part of the steps of implementing the above method embodiments may be completed by using hardware related to program instructions, and the foregoing program may be stored in a computer readable storage medium, and the program is executed when executed. The foregoing steps include the steps of the foregoing method embodiments; and the foregoing storage medium includes: a medium that can store program codes, such as a ROM, a RAM, a magnetic disk, or an optical disk.

FIG. 5 is a structural diagram of Embodiment 1 of a path establishing apparatus according to the present invention. As shown in FIG. 5, this embodiment provides a path establishing apparatus, which may specifically perform the steps in Embodiment 1 of the foregoing method, and details are not described herein again. . The path establishing apparatus provided in this embodiment may specifically include a calculating module 501 and an establishing module 502. The calculation module 501 is configured to calculate a segment protection path for a leaf node to be protected, or calculate a segment recovery path for a leaf node that needs to be restored; where the first node of the segment protection path is a point-to-multipoint P2MP group A node other than the leaf node to be protected on the tree, and having the shortest path or minimum cost from the head node to the leaf node; the first node of the section recovery path is a P2MP multicast tree except for recovery A node outside the leaf node and having the shortest path or minimum cost from the head node to the leaf node. The building module 502 is used to Sending a path message to a head node of the section protection path or the section recovery path, so that the head node of the section protection path or the section recovery path sends the section along the section protection path or the section restoration path to each node on the path A path message, and a section protection path or a section recovery path is established according to the path message.

FIG. 6 is a structural diagram of Embodiment 2 of the path establishing apparatus according to the present invention. As shown in FIG. 6, the embodiment provides a path establishing apparatus, which may specifically perform the steps in Embodiment 2 and Embodiment 3 of the foregoing method. I won't go into details here. The path establishing apparatus provided in this embodiment is based on the foregoing FIG. 5, and the establishing module 502 may specifically include a first sending unit 512, a first establishing unit 522, and a second establishing unit 532. The first sending unit 512 is configured to send, by the source node of the P2MP multicast tree, a path message to each node in the path along each S2L sub-LSP and the section protection path, where the path message carries the P2MP multicast tree. The source node address, the P2MP identifier ID, the label switching path LSP ID, the explicit routing information, and the protection recovery type, where the explicit routing information of the S2L sub-LSP and the section protection path is explicitly routed through the object ER0 or The second explicit routing object SER0 is used to specify; or, the first sending unit 512 is configured to send a path message to the downstream node hop by hop through the source node of the P2MP multicast tree, where the path message carries the source node address of the P2MP multicast tree. The P2MP ID, the LSP ID, the explicit routing information, and the protection recovery type, where the explicit routing information of the S2L sub-LSP is specified by ER0 and SER0, and the explicit routing information of the section protection path passes the ER0 or SER0 to specify. The first establishing unit 522 is configured to establish a P2MP working LSP according to the path message by each node on the P2MP working LSP. The second establishing unit 532 is configured to establish the section protection path according to the path message by a head node of the section protection path.

Further, the second establishing unit 532 in this embodiment may specifically include a first sending subunit 5321, a first establishing subunit 5322, a second establishing subunit 5323, and a third establishing subunit 5324. The first sending sub-unit 5321 is configured to send the path message to each node in the path along the segment protection path by using a first node of the segment protection path, where the path message carries a source of a P2MP multicast tree. Node address, P2MP ID, LSP ID, explicit routing information, and protection recovery type. The first establishing subunit 5322 is configured to: when the protection recovery type is section 1+1 protection, the intermediate node and the last node that pass the section protection path reserve bandwidth on the corresponding link according to the path message. Capital The source establishes a cross-connection in the data plane and returns a reservation message to the respective upstream node, the head node of the section protection path establishing a branch cross-connection to the intermediate node direction. The second establishing subunit 5323 is configured to: when the protection recovery type is the section 1: 1 protection, the intermediate node and the last node that pass the section protection path reserve bandwidth on the corresponding link according to the path message. Resources, establish cross-connections in the data plane, and return reservation messages to their respective upstream nodes. The third establishing subunit 5324 is configured to reserve, by the intermediate node and the last node of the section protection path, the bandwidth resource on the corresponding link according to the path message, when the protection recovery type is the section preset protection. And return a reservation message to the respective upstream node.

Further, the path establishing apparatus provided in this embodiment may further include a first association module 601, where the first association module 601 is configured to use the leaf node according to the path information from the S2L sub-LSP and the section protection path respectively. The source node address, the P2MP ID, and the protection recovery type automatically associate the S2L sub-LSP with the zone protection path.

Further, the establishing module 502 in this embodiment may further include a second sending unit 542, a third sending unit 552, a third establishing unit 562, and a fourth establishing unit 572. The second sending unit 542 is configured to: after the network fault is detected, send a path message to the first node of the section recovery path by using the source node of the P2MP multicast tree, where the path message carries the source node address of the P2MP multicast tree. The P2MP ID, the label switching path LSP ID, the explicit routing information, and the protection recovery type, where the explicit routing information of the section recovery path is specified by SER0. The third sending unit 552 is configured to send the path message to each node in the path along the section recovery path by the first node of the section recovery path. The third establishing unit 562 is configured to reserve a bandwidth resource on the corresponding contact according to the path message by using the intermediate node and the last node in the section recovery path, establish a cross connection in the data plane, and return to the respective upstream node. Reserve a message. The fourth establishing unit 572 is configured to establish a branch cross-connection to the intermediate node by the head node of the section recovery path.

Further, the path establishing apparatus in this embodiment may further include a second association module 602, configured to pass, by the leaf node, the source node in the path message from the section recovery path Address, the P2MP ID and the protection recovery type, and the saved The P2MP information automatically associates the section recovery path with the S2L sub-LSP to select the service of the S2L sub-LSP on the section recovery path.

This embodiment provides a path establishing apparatus, where a source node of a P2MP multicast tree calculates a section protection path or a section recovery path for a leaf node that needs to be protected or restored, and selects a section protection path or a section recovery path. The node is a node other than the leaf node, and the first node to the leaf node has the shortest path or the least cost, and then the source node sends a path message to the first node, and the first node further follows the section protection path or the section recovery path direction. Each node on the path sends a path message, so that each node establishes the section protection path or the section recovery path according to the path message. In this embodiment, the section protection path or the section restoration path is used as a branch of the P2MP working LSP. Instead of a new P2P LSP, the present embodiment only needs to manage one P2MP LSP, which simplifies management; and the segment protection path or the segment recovery path and the P2MP working LSP in this embodiment use the same P2MP ID and LSP ID. , the two are automatically associated, no need to associate each section protection path or section recovery path; The embodiment can implement a section protection path or a section recovery path across different S 2L sub-LSPs, thereby establishing a better path, implementing a more flexible section protection path or section recovery, and improving network resource utilization. rate.

It should be noted that the above embodiments are only for explaining the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: The technical solutions described in the foregoing embodiments are modified, or the equivalents of the technical features are replaced by the equivalents of the technical solutions of the embodiments of the present invention.

Claims

Rights request

A method for establishing a path, comprising:

Calculating a zone protection path for the leaf node to be protected, or calculating a zone recovery path for the leaf node to be restored; wherein the first node of the zone protection path is a point-to-multipoint P2MP multicast tree except for protection a node outside the leaf node, and having the shortest path or minimum cost from the head node to the leaf node, the first node of the section recovery path being a node other than the leaf node to be restored on the P2MP multicast tree And having the shortest path or minimum cost from the head node to the leaf node;

Sending a path message to the section protection path or the head node of the section recovery path, such that the section protection path or the head node of the section recovery path along the section protection path or the area The segment recovery path sends the path message to each node on the path, and establishes the segment protection path or the segment recovery path according to the path message.

2. The method according to claim 1, wherein a path message is sent to a head node of the section protection path such that a head node of the section protection path follows the section protection path to a path Each node sends the path message, and the establishing the segment protection path according to the path message includes:

The source node of the P2MP multicast tree sends a path message to each node in the path along the source-to-leaf sub-label switching path S2L sub-LSP and the section protection path, where the path message carries the source node address of the P2MP multicast tree. The P2MP identifier ID, the label switching path LSP ID, the explicit routing information, and the protection recovery type, where the explicit routing information of the S2L sub-LSP and the explicit routing information of the section protection path pass the explicit routing object ER0 or the second explicit routing object SER0 to specify; or,

The source node of the P2MP multicast tree sends a path message to the downstream node hop by hop, where the path message carries the source node address, the P2MP ID, the LSP ID, the explicit routing information, and the protection recovery type of the P2MP multicast tree, where The explicit routing information of the S2L sub-LSP is specified by ER0 and SER0, and the explicit routing information of the section protection path is specified by ER0 or SER0; Each node on the P2MP working LSP establishes a P2MP working LSP according to the path message; the first node of the section protection path establishes the section protection path according to the path message.

The method according to claim 2, wherein the first node of the section protection path establishes the section protection path according to the path message, including:

The first node of the segment protection path sends the path message to each node in the path along the segment protection path, where the path message carries the source node address, P2MP ID, LSP ID, and explicit of the P2MP multicast tree. Routing information and protection recovery type;

When the protection recovery type is the segment 1+1 protection, the intermediate node and the last node of the segment protection path reserve bandwidth resources on the corresponding link according to the path message, and establish a cross connection in the data plane. And returning a reservation message to the respective upstream node, where the first node of the section protection path establishes a branch cross connection to the intermediate node direction;

When the protection recovery type is a section 1: 1 protection, the intermediate node and the last node of the section protection path reserve bandwidth resources on the corresponding link according to the path message, and establish a cross connection in the data plane, And returning a reservation message to the respective upstream node;

When the protection recovery type is zone preset protection, the intermediate node and the last node of the zone protection path reserve bandwidth resources on the corresponding link according to the path message, and return the pre-predicate to the respective upstream node. Leave the message.

4. The method according to claim 3, further comprising:

The leaf node automatically performs the S2L sub-LSP according to the source node address, the P2MP ID, and the protection recovery type in a path message from the S2L sub-LSP and the section protection path respectively. Associated with the section protection path.

The method according to claim 3 or 4, wherein when a network failure is detected, the method further includes:

When the protection recovery type is the segment 1+1 protection, the leaf node directly switches the service on the failed S2L sub-LSP to the segment protection path associated with the S2L sub-LSP, to Selecting the service on the segment protection path; When the protection recovery type is zone 1: 1 protection, the leaf node sends a failure notification to the source node along the failed S2L sub-LSP, and the source node associates with the area associated with the S2L sub-LSP. The first node of the segment protection path sends a switching command, and the first node establishes a branch cross-connection to the intermediate node in the segment protection path to select the service on the segment protection path;

When the protection recovery type is zone preset protection, the leaf node sends a fault notification to the source node along the failed S2L sub-LSP, and the source node sends a segment associated with the S2L sub-LSP. The first node of the protection path sends a switching command, and the first node sends a path message to each node in the path along the segment protection path, to indicate that the nodes establish a cross connection in the data plane according to the reserved bandwidth resource. The head node establishes a branch cross-connection to the intermediate node direction of the section protection path to select the service on the section protection path.

6. The method according to claim 1, wherein a path message is sent to a head node of the section recovery path such that a head node of the section recovery path follows the section recovery path to a path Each node sends the path message, and establishing the section recovery path according to the path message includes:

After detecting the network fault, the source node of the P2MP multicast tree sends a path message to the head node of the section recovery path, where the path message carries the source node address, the P2MP ID, and the label switching path LSP ID of the P2MP multicast tree. The explicit routing information and the protection recovery type, where the explicit routing information of the section recovery path is specified by ER0 or SER0;

The first node of the section recovery path sends the path message to each node in the path along the section recovery path;

The intermediate node and the last node in the section recovery path reserve bandwidth resources on the corresponding contact according to the path message, establish a cross-connection in the data plane, and return a reserved message to the respective upstream node;

The head node of the section recovery path establishes a branch cross-connection to the intermediate node direction.

7. The method according to claim 6, further comprising: The leaf node automatically recovers the section recovery path and the S2L sub according to the source node address, the P2MP ID, and the protection recovery type in the path message from the section restoration path, and the saved P2MP information. The LSP is associated to select the service of the S2L sub-LSP on the section recovery path.

8. A path establishing device, comprising:

a calculation module, configured to calculate a segment protection path for the leaf node to be protected, or calculate a segment recovery path for the leaf node that needs to be restored; where the first node of the segment protection path is a point-to-multipoint P2MP multicast tree A node other than the leaf node to be protected, and having the shortest path or minimum cost from the head node to the leaf node, the first node of the section recovery path being a leaf on the P2MP multicast tree except for recovery a node outside the node, and having the shortest path or minimum cost from the head node to the leaf node;

The device according to claim 8, wherein the establishing module comprises: a first sending unit, configured to pass the source node of the P2MP multicast tree along each source to the leaf sub-label switching path S2L sub-LSP And the segment protection path respectively sends a path message to each node in the path, where the path message carries a source node address, a P2MP identifier ID, a label switching path LSP ID, an explicit routing information, and a protection recovery type of the P2MP multicast tree, where And the explicit routing information of the S2L sub-LSP and the section protection path is specified by the explicit routing object ER0 or the second explicit routing object SER0; or is used to pass the source node of the P2MP multicast tree downstream The node sends a path message hop by hop, where the path message carries the source node address, the P2MP ID, the LSP ID, the explicit routing information, and the protection recovery type of the P2MP multicast tree, where the explicit routing information of the S2L sub-LSP The explicit routing information of the section protection path is specified by ER0 or SER0, and the first establishing unit is configured to work through the sections on the LSP through the P2MP. According to the path The message establishes a P2MP working LSP;

And a second establishing unit, configured to establish, by the first node of the section protection path, the section protection path according to the path message.

The device according to claim 9, wherein the second establishing unit comprises: a first sending subunit, configured to pass the segment protection path to the path through the segment node of the segment protection path Each of the nodes sends the path message, where the path message carries a source node address, a P2MP ID, an LSP ID, an explicit routing information, and a protection recovery type of the P2MP multicast tree.

a first establishing subunit, configured to: when the protection recovery type is a segment 1+1 protection, the intermediate node and the last node that pass the segment protection path reserve bandwidth on the corresponding link according to the path message Resource, establishing a cross-connection in the data plane, and returning a reservation message to the respective upstream node, the first node of the section protection path establishing a branch cross-connection to the intermediate node direction; the second establishing sub-unit, When the protection recovery type is a zone 1: 1 protection, the intermediate node and the last node that are protected by the segment protection path reserve bandwidth resources on the corresponding link according to the path message, and establish a cross connection in the data plane. And returning a reservation message to the respective upstream node; the third establishing subunit, configured to: when the protection recovery type is the segment preset protection, the intermediate node and the last node that pass the segment protection path according to the The path message reserves bandwidth resources on the corresponding link and returns a reservation message to the respective upstream node.

The device according to claim 10, further comprising:

a first association module, configured to automatically, by using the leaf node, the S2L sub according to the source node address, the P2MP ID, and the protection recovery type in a path message from the S2L sub-LSP and the section protection path respectively - LSP is associated with the zone protection path.

The device according to claim 8, wherein the establishing module comprises: a second sending unit, configured to: after the network fault is detected, recover the first path of the path by using the source node of the P2MP multicast tree The node sends a path message, where the path message carries a source node address, a P2MP ID, a label switched path LSP ID, an explicit routing information, and a protection recovery type of the P2MP multicast tree, where the explicit path of the section recovery path is Information is specified by SER0; a third sending unit, configured to send, by the first node of the section recovery path, the path message to each node in the path along the section recovery path;

a third establishing unit, configured to reserve a bandwidth resource on the corresponding contact according to the path message by using the intermediate node and the last node in the section recovery path, establish a cross connection in the data plane, and return to the respective upstream node Reservation message

And a fourth establishing unit, configured to establish, by the head node of the section recovery path, a branch cross connection to the intermediate node direction.

The device according to claim 12, further comprising:

a second association module, configured to automatically, by the leaf node, according to the source node address, the P2MP ID, and the protection recovery type in the path message from the section recovery path, and the saved P2MP information The segment recovery path is associated with the S2L sub-LSP to select the service of the S2L sub-LSP on the segment recovery path.