WO2009074057A1

WO2009074057A1 - A head node protection method, a system and a device for the point-to-multipoint label switch path

Info

Publication number: WO2009074057A1
Application number: PCT/CN2008/073184
Authority: WO
Inventors: Guoyi Chen; Wei Cao
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-11-30
Filing date: 2008-11-25
Publication date: 2009-06-18
Also published as: CN101453414B; CN101453414A

Abstract

A head node protection method, a system and a device for the point-to-multipoint label switch path. The method includes: a backup head node BHN establishes a backup label switch path LSP from itself to a merge point MP according to a point-to-multipoint head group identifier P2MP Head Group ID,where the LSP does not include the master head node MHN; during the process that the MHN forwards data along the LSP from itself to the merge point MP, the BHN is switched to the master head node and the data is forwarded along the backup LSP when the head node switching condition is met. The BHN establishes the backup LSP according to the P2MP Head Group ID. For the node downstream from the MP, the same common PSMP Head Group ID of the protected LSP established by the MHN and the backup LSP comes from the same P2MP Head Group ID carried by the message of the LSP or backup LSP. The protection for the head node is realized efficiently and the P2MP LSP protection mechanism is improved.

Description

Head node protection method, system and device for point-to-multipoint label switched path

This application claims priority to Chinese Patent Application No. 200710195497.7, entitled "Head Node Protection Method, System and Equipment for Point-to-Multipoint Label Switching Paths", filed on November 30, 2007, The entire contents are incorporated herein by reference. Technical field

The present invention relates to the field of communications technologies, and in particular, to a head node protection method, system, and device based on a point-to-multipoint label switching path (P2MP LSP).

Background technique

Multicast is a one-to-many multiparty communication method. Different from the commonly used unicast technology, multicast technology can reduce the consumption of network resources by multi-party communication by establishing an optimal multicast forwarding path and reducing the replication of data content.

Multi-protocol label switching (MPLS) is a routing technology widely used in IP networks. Label distribution is generally used by Label Distribution Protocol (LDP). In the past, MPLS was mainly used for unicast IP forwarding. With the development of multicast technology and the rise of Internet Protocol Television (IPTV), MPLS multicast has gradually become a research hotspot. There are two main methods for constructing P2MP LSPs: LDP-based and Resource Reservation Protocol-Traffic Engineering (RSVP-TE). From the current technical development, RS VP-TE The way is gradually becoming mainstream.

MPLS-based multicasting currently offers a variety of protection schemes, the most common being path protection and local protection.

The path protection is implemented by establishing an additional standby P2MP LSP in parallel with the existing primary P2MP LSP. When the existing primary LSP fails, the traffic is directly switched to the standby LSP. Both the primary LSP and the backup LSP are configured at the head end, and they are one-to-one.

Local protection is divided into link protection and node protection. Link protection is to establish a unicast backup LSP that bypasses the protected link in advance for the link to be protected, so that there is a problem when the protected link is faulty. The data traffic can be switched to the standby LSP; the node protection is to establish a unicast backup LSP bypassing the protected node in advance, so as to data traffic when the protected node fails. Switch to the backup LSP. The backup LSP and the primary LSP can be one-to-many. The backup LSP can protect multiple active LSPs.

At present, for the protection of P2MP LSP, a technique called bypass tunnel is proposed. For a link or node that needs to be protected, a point-to-multipoint bypass tunnel that bypasses the protected link or node is established in advance. (P2MP Bypass Tunnel), which greatly reduces the replication of messages when the protected path or node fails.

In view of the need to protect the egress node of the multicast tree in the current deployment of MPLS multicast, a protection technology for Egress has been proposed.

In implementing the present invention, the Applicant has found that the prior art has at least the following drawbacks: For P2MP LSPs, although there are multiple protection techniques, there is no scheme for protecting the head node. However, in actual deployments, especially in the deployment of IPTV, the protection requirements for the head node are getting stronger and stronger; because the failure of the head node means the interruption of all user services under the entire P2MP tree. Protection from the head node is more important than any other protection in terms of protection and in terms of protection.

Summary of the invention

The embodiments of the present invention provide a method, a system, and a device for protecting a head node of a point-to-multipoint label switching path to implement protection on a head node.

The embodiment of the invention provides a method for protecting a head node of a point-to-multipoint label switching path, the method comprising:

The backup head node BHN establishes itself in the process of forwarding data according to the LSP established by the MHN along its own and the aggregation node MP according to the point-to-multipoint head group identifier P2MP Head Group ID. When the head node handover condition is met, the BHN handover The primary head node forwards data along the backup LSP.

The embodiment of the present invention further provides a head node protection system for a point-to-multipoint label switching path of a backup head node BHN, including:

a primary head node MHN, configured to forward data along an established LSP between the MHN and the aggregation node MP; The backup head node BHN is configured to establish a backup label switching path LSP to the aggregation node MP according to the P2MP Head Group ID, where the backup LSP does not include the primary head node MHN; when the head node switching condition is met, the host is switched to the primary head a node, and forwards data along the backup LSP.

The embodiment of the present invention further provides a backup head node BHN, including:

a backup LSP establishing unit, configured to establish a backup LSP from the BHN to the MP according to the P2MP Head Group ID, where the backup LSP does not include the MHN;

a switching unit, configured to: when the head node switching condition is met, switch the BHN as a primary head node, and notify the data transmission unit of the message that the BHN is switched to be a primary head node;

a data transmission unit, configured to forward data along the backup LSP.

An embodiment of the present invention further provides a primary head node MHN, including:

a label switching path LSP establishing unit, configured to establish an LSP from the MHN to the aggregation node MP, and a switching unit, configured to switch itself to a non-primary node when the head node switching condition is met, to generate a stop transmission notification;

And a data transmission unit, configured to forward data along the established LSP between the MHN and the MP; and, after receiving the stop transmission notification from the switching unit, stop forwarding data along the established LSP between the MHN and the MP.

The embodiment of the present invention provides a solution for protecting a head node. The BHN establishes a backup LSP according to the P2MP Head Group ID. The P2MP Head Group ID is globally unique. Therefore, the protected LSP established by the MHN and the backup LSP share the same P2MP. Head Group ID. Thus, for the MP, the backup LSP is considered as a backup path established for link protection between the MP and the MHN. For the node under the MP, the message from the LSP or the backup LSP carries the same message. P2MP Head Group ID, therefore, even if the head node is switched, the node under the MP does not feel the change of the head node, which protects the head node well, and improves the protection mechanism of the P2MP LSP; Scale deployment.

DRAWINGS

1 is a schematic diagram of a network structure for protecting a primary head node according to an embodiment of the present invention;

2 is a schematic diagram of a process of protecting a head node of a P2MP LSP according to an embodiment of the present invention.

detailed description

The invention is described in detail below. Before introducing a specific solution, first introduce a few terms:

MHN (Master Head Node): For a given P2MP LSP, MHN is the head node that originally initiated the establishment of this P2MP LSP;

Aggregate node (MP, Merge Point): For a P2MP LSP, in this scheme, those leaf points or branch points directly connected to the MHN are called MP nodes, and the MP nodes may be one or more. ;

Backup Head Node (BHN): For a given P2MP LSP, BHN establishes its own backup P2MP LSP to all MPs for a given P2MP LSP. When MHN fails, BHN replaces MHN as the head node.

Point-to-multiple head group (P2MP Head Group): Define one or more point-to-multipoint head nodes as point-to-multipoint head groups. Nodes in a point-to-multipoint head group can be used as the head of all P2MP LSPs in a P2MP tunnel. node.

P2MP Head Group ID: The identifier of a point-to-multiple head group, which is a unique address within the network where the P2MP service is provided. FIG. 1 is a schematic diagram of a network structure for protecting a primary head node according to an embodiment of the present invention. The thick solid line in the figure is the established P2MP LSP, and the line with the arrow is the LSP tunnel.

FIG. 2 is a schematic diagram of a process of protecting a head node of a P2MP LSP according to an embodiment of the present invention. Step 201: The BHN establishes its own backup LSP to all MPs according to the P2MP Head Group ID, and the backup LSP does not include the MHN.

The P2MP Head Group ID can be obtained through static configuration or synchronization. You can manually configure the same P2MP Head Group ID on the MHN and BHN or configure it through the NMS.

The P2MP Head Group ID can also be obtained by synchronizing the MHN with the BHN.

According to the method proposed by the embodiment of the present invention, when the P2MP Head Group ID needs to be obtained by synchronizing the MHN and the BHN, the following operations are performed:

It can be negotiated: ΒΗΝ send the first ΜΡ 2ΜΡ Head Group ID to the ΜΗΝ through the synchronization message; BHN sends the second P2MP Head Group ID to the MHN through the synchronization message; MHN and The BHN selects one of the first P2MP Head Group ID and the second P2MP Head Group ID as the P2MP Head Group ID according to the same rule. For example, the first one of the first P2MP Head Group ID and the second P2MP Head Group ID is selected as the P2MP Head Group ID, or the first P2MP Head Group ID and the second P2MP Head Group ID are selected as the P2MP Head Group ID.

You can also use the notification mode: Configure the P2MP Head Group ID only on the MHN; MHN sends the P2MP Head Group ID to the BHN through the synchronization message; or, configure the P2MP Head Group ID only on the BHN; BHN will use the synchronization message. The P2MP Head Group ID is sent to the P2MP Head Group ID, which can correspond to the P2MP tunnel, in order to ensure the P2MP Head.

The global uniqueness of the group ID. The P2MP Head Group ID can be one of the address of the MHN, the address of the BHN, the traffic engineering router identifier of the MHN, the TE Router ID, and the TE Router ID of the BHN. It can also be other globally unique addresses.

Step 202: Normally, the MHN forwards data along the established LSP between the MHN and the MP. Step 203: When the head node switching condition is met, the BHN switches to the primary node, along the BHN and

The backup LSP between the MPs forwards the data.

When you need to "head node" protection, do the following:

1. For a specific P2MP LSP, first, the MHN needs to obtain the basic information of the BHN, and then the MHN sends the path characteristic information of the P2MP LSP that needs to be protected by the head node to the BHN.

The path feature information that the MHN passes to the BHN can be carried through the RSVP-TE Path message, or a new message format can be defined to carry the information.

The manner in which the MHN needs to obtain the basic information of the BHN may include: the MHN obtains the basic information of the BHN by querying the network management; or, the MHN obtains the basic information of the BHN by using the received configuration information, or the MHN receives the received BHN from the BHN. Active notification, get basic information about BHN. The basic information of the BHN includes address and capability information of the BHN.

The manner in which the foregoing MHN sends the path feature of the P2MP LSP that needs to be protected by the head node to the BHN includes: A path is established between the MHN and the BHN, and the path feature information of the P2MP LSP that needs to be protected by the head node is encapsulated in the newly defined message, and the path feature information is directly sent to the BHN by using the newly defined message; or,

The path information of the resource reservation protocol RSVP-TE based on the traffic engineering extension is extended, and the MHN directly sends the path feature information to the BHN through the extended Path message; or

Extending the Path message of the resource reservation protocol RSVP-TE based on the traffic engineering extension, the MHN sends the path feature information to the MP through the extended Path message, and then the MP sends the received path feature information to the BHN; Or,

The MHN sends the path feature information to the BHN through the network management.

The foregoing method for extending the Path message of the RSVP-TE resource reservation protocol based on the traffic engineering extension includes: adding a new object (Object), or extending an existing object (Object).

The path feature information includes a point-to-multipoint session object (SESSION Object), a sender template object (SENDER_TEMPLATE Object), and all MP node address information; and may further include basic information of the BHN and other necessary information; or The path feature information described above includes a point-to-multipoint identifier (P2MP ID) and an extended tunnel identifier (Extended Tunnel ID) in a point-to-multipoint session object, and a sender address (Sender Address) in the sender template object, Sub-Group Originator ID and point-to-multipoint (LSP ID LSP ID), and all MP node address information; and may further include basic information of the BHN and other necessary information.

2. When the BHN receives the Path message or the newly defined message, it analyzes the received message, extracts the path feature information from the BHN, and saves the path information. Then, the BHN uses the path feature information to establish one or more MHNs. Backup LSP from BHN to all MP nodes; these LSPs can be point-to-point LSPs or point-to-multipoint LSPs.

The path feature information includes a point-to-multipoint session object (SESSION Object), a sender template object (SENDER_TEMPLATE Object), and all MP node address information; or, the path feature information includes a point in a point-to-multipoint session object to Multi-point identifier (P2MP ID) and extended tunnel identifier (Extended Tunnel ID), sender address (Sender Address), sub-group Originator ID, and point-to-multipoint in the sender template object LSP ID (LSP ID), and all MP node address information. It can be understood that the information received by the BHN may be from the MHN or the MP or the network management. When the information received by the BHN is from the MP or the network management, the foregoing path feature information should also include the basic information of the BHN for the MP or the network management to transmit.

The steps for the BHN to establish a point-to-point LSP include:

The BHN generates a Path message for each MP, and sends the Path message to the MP. The Path message carries the path feature information, and the LSP is an identifier of the backup information of the P2MP LSP. LSP establishment priority, retention priority, protection mode (for example: node protection or link protection, whether local repair is allowed, whether some links should be included, whether certain links should be excluded, etc.), bandwidth requirements, etc.

After receiving the Path message, the MP allocates a label, reserves a resource, returns a response message to the BHN through a RESV message, and binds the LSP to the protected P2MP LSP (the binding here refers to the MP). The path feature information carried in the Path message is compared with the path feature information of the existing LSP. If the Session Object and the LSP ID are the same, the backup LSP is associated with the protected P2MP LSP. Establishing; when receiving data from the backup LSP, the MP forwards the received data along a subtree with the MP as a root node, and the subtree is part of the protected P2MP LSP.

Point-to-point LSPs can be found in more detailed procedures for RFC3209 and RFC3471.

The steps for the BHN to establish a point-to-multipoint LSP include:

The BHN generates a Path message and sends it to the MP. The Path message carries the path feature information, and the LSP is the identifier of the backup information of the P2MP LSP. The Path message can also carry the backup LSP establishment priority and keep the priority. , protection mode (for example: node protection or link protection, whether local repair is allowed, whether some links should be included, whether some links should be excluded, etc.), bandwidth requirements, etc.; In this step, the Path generated by BHN The message may be one or more. If the BHN generates a Path message, the Path message belongs to all the MPs. If the BHN generates multiple Path messages, the following two situations may occur: Each Path message corresponds to an MP. Or, a Path message corresponds to multiple MPs, which can be determined according to actual needs; BHN establishes a P2MP LSP with BHN as the root and all MP nodes as leaves;

After receiving the Path message, the MP allocates a label, reserves a resource, returns a response message to the BHN through a RESV message, and binds the LSP to the protected P2MP LSP (here) Binding refers to the fact that the MP uses the path feature information carried in the received Path message and the path feature information of the existing LSP. If the Session Object and the LSP ID are the same, the backup LSP is associated with the protected P2MP LSP. And completing the establishment of a backup LSP; when receiving data from the backup LSP, the MP forwards the received data along a subtree with the MP as a root node, where the subtree is the Protect a part of the P2MP LSP.

Point-to-multipoint LSPs can be referred to the existing standard specification RFC4875 for a more detailed setup process.

3. The MHN can actively trigger the handover of the head node. In this case, the MHN sends a notification message to the BHN to inform the BHN to perform the handover of the head node. After receiving the handover notification message, the BHN starts to be established along the BHN and the MP. LSP forwards data. BHN can also find MHN failure through some fault detection mechanisms (such as bidirectional forwarding detection (BFD), fast Hello message); if BHN detects MHN failure, BHN switches itself to the primary node and starts to move along between BHN and MP. The established LSP forwards data. That is to say, satisfying the head node switching condition may include: MHN active triggering head node switching or BHN detecting MHN failure.

When the MHN is restored to the working state, the MHN needs to re-establish the P2MP LSP. The specific establishment mode may be that the MHN independently establishes the P2MP LSP, or the BHN retransmits the path feature information of the P2MP LSP from the MHN that needs the protection of the head node to the MHN. To assist the MHN to re-establish a P2MP LSP. Here, the manner in which the BHN retransmits the path characteristic information to the MHN is the same as the transmission mode in 1.

After the MHN returns to the normal state, the BHN notifies the MHN to perform the head node handover or the MHN notifies the BHN to actively request the handover back. After the handover, the BHN stops forwarding data along the established LSP between the BHN and the MP, and the MHN acts as a head node along the MNN. The established LSP between the MP and the MP forwards the data. The manner in which the BHN notifies the MHN to perform the head node handover includes: the BHN directly notifies the MHN to perform the head node handover; or the BHN notifies the MHN to perform the head node handover through the network management.

In the process of establishing a backup LSP, the SESSION Object carried in the path message is the same. The SESSION Object defines a P2MP ID, a P2MP tunnel ID, and an Extended Tunnel ID. In the embodiment of the present invention, the address of the sender is used to replace the address of the sender (Ingress LSR), and the address of the sender is replaced by the P2MP Head Group ID in the extended tunnel ID. The embodiment of the present invention further provides a head node protection system for a point-to-multipoint label switching path of a backup head node BHN, including:

a primary head node (MHN) for forwarding data with established LSPs along the MHN and the MP; a backup head node (BHN) for establishing a backup label switching path from itself to all the aggregation nodes MP according to the P2MP Head Group ID LSP, the backup LSP does not include the MHN. When the head node handover condition is met, the BHN switches to the primary node, and the data is forwarded along the established backup LSP between the BHN and the MP.

The head node switching conditions are met: MHN actively triggers the head node switching or the BHN detects the MHN failure.

When the MHN is restored to the working state, it is also used to re-establish the P2MP LSP.

The BHN is further configured to notify the MHN to perform head node handover after the MHN returns to a normal state. After the handover, the BHN stops forwarding data along the established backup LSP between the MN and the MP, and the MHN acts as a head node edge. The L SP that has been established between it and the MP forwards the data.

The MHN is further configured to notify the BHN line head node to switch after the MHN returns to a normal state. After the handover, the BHN stops forwarding data along the established backup LSP between the BHN and the MP, and the MHN acts as a head node along the MNN. The established L SP between the MP and the MP forwards the data.

The backup LSP establishing unit is configured to establish a backup LSP to all MPs according to the P2MP Head Group ID, and the backup LSP does not include the MHN;

The switching unit is configured to switch itself to the primary node when the head node switching condition is met, and notify the data transmission unit;

A data transmission unit, configured to forward data along an established backup LSP between the BHN and the MP. The BHN also includes:

The synchronization unit is used to synchronize the point-to-multipoint head group identifier of the primary head node MHN and the backup head node BHN, P2MP Head Group ID.

Further, the synchronization unit includes:

a sending subunit, configured to send a second P2MP Head Group ID to the MHN by using a synchronization message; and a receiving subunit, configured to receive a first P2MP Head Group ID from the MHN; The selecting subunit is configured to select one of the first P2MP Head Group ID and the second P2MP Head Group ID as the P2MP Head Group ID according to the same rule as the MHN.

Alternatively, the synchronization unit includes:

a configuration subunit, configured to configure a P2MP Head Group ID;

A sending subunit, configured to send the P2MP Head Group ID to the MHN by using a synchronization message.

The BHN may further include: an information feedback unit, configured to resend path feature information of the P2MP LSP from the MHN that needs to be protected by the head node to the MHN, to assist the MHN to re-establish the P2MP LSP.

The BHN may further include a notification unit, configured to notify the MHN to perform the switchover of the head node, and then notify the switching unit of the switching information;

The switching unit is further configured to switch to a non-primary node according to the received notification, and notify the data transmission unit;

The data transmission unit is further configured to stop forwarding data along the established backup LSP between the BHN and the MP.

The embodiment of the present invention further provides a primary head node MHN, including:

An LSP establishing unit, configured to establish an LSP from the MHN to all MPs;

The switching unit is configured to switch itself to a non-primary node when the head node switching condition is met, and notify the data transmission unit to stop transmitting data;

a data transmission unit, configured to forward data along an established LSP between the MHN and the MP; and after receiving the stop transmission notification from the switching unit, stop forwarding data along the established LSP between the MHN and the MP.

The primary node MHN may also include:

The LSP establishment unit is also used to re-establish the P2MP LSP when the MHN is restored to the working state. The switching unit is further configured to notify the BHN to perform head node switching after determining that the MHN returns to a normal state. Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary hardware platform, and of course, all can be implemented by hardware. Based on such understanding, all or part of the technical solution of the present invention contributing to the background art may be embodied in the form of a software product, which may be stored in a storage medium. Such as ROM/RAM, diskette, optical disk, etc., including instructions for causing a computer device (which may be a personal computer, server, or network device, etc.) to perform the various embodiments of the present invention or portions of the embodiments described herein. method.

The above description is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It is considered as the scope of protection of the present invention.

Claims

Rights request

A method for protecting a head node of a point-to-multipoint label switching path, the method comprising:

2. The method according to claim 1, wherein the P2MP Head Group ID is obtained by:

The same P2MP Head Group ID is configured on the MHN and the BHN.

The method according to claim 1, wherein the P2MP Head Group ID is obtained by synchronizing the primary head node MHN with the backup head node BHN.

The method according to claim 3, wherein the MHN is synchronized with the BHN, and the P2MP Head Group ID includes:

Sending, by the synchronization message, the first P2MP Head Group ID to the BHN by using a synchronization message;

Sending, by the synchronization message, the second P2MP Head Group ID to the MHN by using a synchronization message;

The MHN and the BHN select one of the first P2MP Head Group ID and the second P2MP Head Group ID as the P2MP Head Group ID according to the same rule.

5. The method according to claim 3, wherein the MHN is synchronized with the BHN P2MP

Head Group ID includes:

Configuring a P2MP Head Group ID on the MHN;

Sending, by the MHN, the P2MP Head Group ID to the BHN by using a synchronization message; or

Configuring a P2MP Head Group ID on the BHN;

The BHN sends the P2MP Head Group ID to the MHN through a synchronization message.

The method according to any one of claims 1 to 5, wherein the P2MP Head Group ID is an address of the MHN, an address of the BHN, and a traffic engineering router of the MHN. The identifier TE Router ID, the TE router ID of the BHN, and other globally unique addresses.

The method according to any one of claims 1 to 5, wherein the backup head node BHN establishes itself to the aggregation node MP according to the point-to-multipoint head group identifier P2MP Head Group ID, not including the main Before the backup label switching path LSP of the head node MHN, the method further includes: receiving information for establishing the backup LSP that is sent by the MHN and required to be protected by the head node.

The method according to any one of claims 1 to 5, wherein the head node switching condition comprises:

The MHN actively triggers a head node switch or the BHN detects an MHN failure.

A head node protection system for a point-to-multipoint label switching path, comprising: a primary head node MHN, configured to forward data along an established LSP between the MHN and the aggregation node MP;

The backup head node BHN is configured to establish a backup label switching path LSP to the aggregation node MP according to the P2MP Head Group ID, where the backup LSP does not include the primary head node MHN; when the head node switching condition is met, the host is switched to the primary head a node, and forwards data along the backup LSP.

10. A backup head node BHN, comprising:

a data transmission unit, configured to forward data along the backup LSP.

The backup head node BHN according to claim 10, wherein the BHN further comprises:

The backup head node BHN according to claim 11, wherein the BHN further comprises: And an information feedback unit, configured to resend path feature information of the P2MP LSP from the MHN that needs to be protected by the head node to the MHN.

The backup head node BHN according to claim 11, wherein the BHN further includes a notification unit, configured to notify the MHN to generate handover information after performing head node handover;

The switching unit is further configured to switch to the non-primary node according to the received switching information from the notification unit, and notify the data transmission unit;

14. A master node MHN, characterized in that:

The primary node MHN according to claim 14, wherein the MHN further comprises: a synchronization unit, a point-to-multipoint head group identifier P2MP Head Group ID for synchronizing the primary head node MHN and the backup head node BHN. .

16. The master node MHN of claim 14 wherein:

The switching unit is further configured to notify the backup head node BHN to perform head node switching after the MHN is restored to the normal state.