CN101453414B - Head node protection method, system and equipment for point to multiple points label switch path - Google Patents

Abstract

The invention discloses a head node protection method, system and equipment of a point-to-multipoint label switching path. The method includes: the main head node MHN forwards data along the established LSP between the MHN and the aggregation node MP; When the node switching condition occurs, switch to the backup head node BHN, forward data along the backup LSP, the LSP is the label switching path LSP from the BHN to the MP, and the backup label LSP is established according to the P2MPHead Group ID. BHN establishes backup LSP according to P2MP Head Group ID. The protected LSP and backup LSP established by MHN share the same P2MP Head Group ID. For nodes under MP, messages from LSP or backup LSP carry the same P2MP Head Group ID. It realizes the protection of the head node very well, and greatly improves the protection mechanism of the P2MP LSP.

Description

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

technical field

The present invention relates to the field of communication technologies, in particular to a head node protection method, system and equipment based on a point-to-multipoint label switching path (P2MPLSP, Point to Multipoint LSP).

Background technique

Multicast technology (Multicast) is a one-to-many multi-party communication method. Different from the commonly used unicast technology, the multicast technology can greatly reduce the consumption of network resources by multi-party communication by establishing an optimal multicast forwarding path and reducing the duplication of data content. The most important pure IP multicast protocol at present is the Protocol Independent Multicast (PIM, Protocol Independent Multicast) protocol.

Multi-protocol label switching technology (MPLS, Multiple protocol label switch) is a routing technology widely used in IP networks at present, and the label distribution generally adopts the Label Distribution Protocol (LDP, Label Distribution Protocol) protocol. In the past, MPLS was generally used for unicast IP forwarding. Now, with the development of multicast technology and the rise of Internet-based electrical systems (IPTV, Internet Protocol Television), MPLS multicast has gradually become a research hotspot. Currently, there are two main P2MP LSP construction methods: the LDP-based method and the Resource Reservation Protocol-Traffic Engineering-based method (RSVP-TE, ResourceReservation Protocol-Traffic Engineering). From the perspective of current technological development, the RSVP-TE method is positive Gradually become mainstream.

MPLS-based multicast can provide a variety of protection schemes, the most common ones are path protection (Pathprotection) and local protection.

Path protection is realized by establishing an additional standby P2MP LSP in parallel with the existing active P2MP. When the existing active LSP fails, the traffic is directly switched to the standby LSP. Both the active LSP and the standby LSP are configured at the headend, and they have a one-to-one relationship.

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 when there is a problem with the protected link , the data traffic can be switched to the backup LSP; node protection is to establish a unicast backup LSP bypassing the protected node in advance, so that the data traffic can be switched to the backup LSP when the protected node fails. In partial protection, the backup LSP and the active LSP may have a one-to-many relationship, that is, one backup LSP can protect multiple active LSPs.

At present, for the protection of P2MP LSP, a technology called bypass tunnel (Bypass Tunnel) is proposed. For the link or node to be protected, a point-to-multipoint bypass tunnel bypassing the protected link or node is established in advance. (P2MP Bypass Tunnel), which greatly reduces the duplication of packets when the protected path or node fails.

Aiming at the requirement that the egress node (egress) of the multicast tree may need to be protected in the current MPLS multicast deployment, a protection technology for the egress is also proposed.

In the process of realizing the present invention, the applicant found that the existing technology has at least the following defects: for P2MPLSP, although there are multiple protection technologies, there is no scheme for protecting the head node (Head Node). However, in actual deployment, especially in the deployment of IPTV, the protection requirement for the head node is getting stronger; because the failure of the head node means the interruption of all user services under the entire P2MP tree. In terms of the effect and meaning of protection, the protection of the head node is more important than any other protection.

Contents of the invention

Embodiments of the present invention provide a head node protection method, system and device for a point-to-multipoint label switched path, so as to protect the head node.

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

The main head node MHN forwards data along the established LSP between the MHN and the aggregation node MP;

When the head node switching condition is met, switch to the backup head node BHN, forward data along the backup label switching path LSP, the LSP is the label switching path LSP from the BHN to the aggregation node MP, and the backup label switching path LSP is based on The point-to-multipoint group identifier P2MP Head Group ID is established.

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

The main head node MHN is used to forward data along the established LSP between MHN and MP;

The backup head node BHN is used to establish a backup label switching path LSP from itself to the aggregation node MP according to the P2MP Head Group ID. The backup LSP does not include the main head node MHN; when the head node switching condition is met, the BHN switches to the head node , forwarding data along the backup LSP.

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

A backup LSP establishment unit is used to set up backup LSPs from the BHN to all MPs according to the P2MP Head Group ID, and the backup LSPs do not include the MHN;

The switching unit is used to switch the BHN as the head node and notify the data transmission unit when the head node switching condition is met;

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

Since the embodiment of the present invention provides a scheme for protecting the head node, the BHN establishes a backup LSP according to the P2MP Head Group ID, and the P2MP Head Group ID is unique globally, so the protected LSP and the backup LSP established by the MHN share the same P2MP Head Group ID, so, for the MP, the backup LSP is considered to be a backup path established for link protection between the MP and the MHN. For the nodes below the MP, the messages from the LSP or the backup LSP carry the same P2MP HeadGroup ID, therefore, even if the switch of the head node occurs, the nodes under the MP will not feel the change of the head node, which realizes the protection of the head node well, and greatly improves the protection mechanism of P2MP LSP; thus, it can promote the scale of P2MP deploy.

Description of drawings

FIG. 1 is a schematic diagram of a network structure of a protection master head node according to an embodiment of the present invention;

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

Detailed ways

The present invention will be described in detail below.

Before introducing the specific scheme, first introduce a few terms:

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

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

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

Point-to-multipoint group (P2MP Head Group): define one or more point-to-multipoint nodes as a point-to-multipoint group, and the nodes in the point-to-multipoint group can be used as the heads of all P2MP LSPs in a P2MP Tunnel node.

Point-to-multiple head group identifier (P2MP Head Group ID): The identifier of the point-to-multiple head group, which is the unique address of the point-to-multiple head group in the network where the P2MP service is provided.

FIG. 1 is a schematic diagram of a network structure of a protection master 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 protection tunnel (LSP tunnel).

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

Step 201, the BHN establishes backup LSPs from itself to all MPs according to the P2MP Head Group ID, and the backup LSP does not include the MHN.

Step 202, under normal circumstances, the MHN forwards data along the established LSP between the MHN and the MP.

Step 203, when the head node switching condition is satisfied, the BHN switches to the head node, and forwards data along the established backup LSP between the BHN and the MP.

The same P2MP Head Group ID can be manually configured on MHN and BHN through static configuration, or configured through network management.

The P2MP Head Group ID can also be obtained through MHN and BHN synchronization.

According to the method that the embodiment of the present invention proposes: when needing to obtain P2MP Head Group ID by the mode of MHN and BHN synchronization, carry out following operations:

It can be negotiated: MHN sends the first P2MP HeadGroup ID to BHN through a synchronization message; BHN sends the second P2MP Head Group ID to the MHN through a synchronization message; Select one of the P2MP Head Group IDs as the P2MP Head Group ID. For example, select the larger of the first P2MP Head Group ID and the second P2MP Head Group ID as the P2MP Head Group ID, or select the smaller of the first P2MP Head Group ID and the second P2MP Head Group ID as the P2MP Head Group ID.

The way of notification can also be used: only configure P2MP Head Group ID on MHN; MHN sends P2MP Head Group ID to the BHN through synchronization message; or, only configure P2MP Head Group ID on BHN; BHN sends P2MP Head Group ID through synchronization message The Head Group ID is sent to the MHN.

The P2MP Head Group ID can correspond to the P2MP tunnel one by one. In order to ensure the global uniqueness of the P2MP HeadGroup ID, the P2MP Head Group ID can be the address of the MHN, the address of the BHN, the traffic engineering router identifier of the MHN TE Router ID and the TE of the BHN One of the Router IDs can also be other globally unique addresses.

When "head node" protection is required, perform the following operations:

1. For a specific P2MP LSP, the MHN first needs to obtain the basic information of the BHN, and then the MHN sends the information for establishing the protected path that requires the head node to protect the P2MP LSP to the BHN. The information for establishing the protected path transmitted by the MHN to the BHN may be carried by a path (Path) message of RSVP-TE, or a new message format may be defined to carry such information.

The manner in which the above-mentioned 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 manager; Get the basic information of BHN through voluntary notification. The basic information of the BHN includes the address and capability information of the BHN.

The ways in which the above-mentioned MHN sends the information used to establish the protected path to the BHN include:

Establish a connection between the MHN and the BHN, pack the information for establishing the protected path in the newly defined message, and directly send the information for establishing the protected path to the BHN through the newly defined message ;or,

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

Extend the Path message of the resource reservation protocol RSVP-TE based on traffic engineering extension, and the MHN sends the information used to establish the protected path to the MP through the extended Path message, and then the MP sends the received information to the BHN ;or,

The MHN sends the information for establishing the protected path to the BHN through the network management.

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

The above-mentioned information used to establish the protected path includes point-to-multipoint session object (SESSIONObject), sender template object (SENDER_TEMPLATE Object) and all MP node address information; in addition, it can further include basic information of BHN and other necessary information, etc.; Alternatively, the above information used to establish the protected path includes the point-to-multipoint identifier (P2MP ID) and the extended tunnel identifier (Extended Tunnel ID) in the point-to-multipoint session object, and the sender address in the sender template object (Sender Address), Sub-Group Originator ID (Sub-Group Originator ID) and point-to-multipoint (LSP ID LSP ID), and all MP node address information; in addition, it can further include basic information of BHN and other necessary information wait.

2. When BHN receives a Path message or a newly defined message message, it analyzes the received message, extracts the path feature information from it and saves it; Backup LSP of the MP node; these LSPs can be point-to-point LSPs or point-to-multipoint LSPs.

The above-mentioned path feature information includes point-to-multipoint session object (SESSION Object), sender template object (SENDER_TEMPLATE Object) and all MP node address information; or, the above-mentioned path feature information includes point-to-multipoint session object in point-to-multipoint session object Identifier (P2MP ID) and extended tunnel identifier (Extended Tunnel ID), sender address (SenderAddress), sub-group originator ID (Sub-Group Originator ID) and point-to-multipoint LSP ID in the sender template object (LSP ID), and all MP node address information.

It can be understood that the information received by the above-mentioned BHN can come from the MHN or MP or the network management. When the information received by the BHN comes from the MP or the network management, the aforementioned information used to establish the protected path should also include the basic information of the BHN, so that the MP or transmitted by the network management system.

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

BHN generates a Path message respectively for each MP, and sends to described MP, carries path feature information in the described Path message, and this LSP is the mark of the backup information of P2MP LSP; In addition, also can carry backup in the described Path message P2MP LSP establishment priority, maintenance 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 and other information ;

After the MP receives the Path message, it allocates labels, reserves resources, returns response information to the BHN through the RESV message, and binds this LSP with the protected P2MP LSP (the binding here refers to the MP Use the path feature information carried in the received Path message to compare with the path feature information of the local existing LSP. If the Session Object and LSP ID are the same, it means that the backup LSP is associated with the protected LSP), and a backup LSP is completed. Establish; when receiving data from the backup LSP, the MP forwards the received data along the subtree with the MP as the root node, and this subtree is a part of the protected P2MP LSP.

Refer to RFC3209 and RFC3471 for more detailed procedures of establishing a point-to-point LSP.

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

The BHN generates a Path message and sends it to the MP. The Path feature information is carried in the Path message, and this LSP is the identification of the backup information of the P2MP LSP; in addition, the Path message can also carry the establishment priority and maintenance priority of the backup P2MP LSP Level, 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 and other information; in this step, the BHN generated There can be one or more Path messages. If BHN generates one Path message, the Path message is relevant to all MPs; if BHN generates multiple Path messages, it may be the following two situations: each Path message corresponds to one MP, or, one 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 the MP receives the Path message, it allocates labels, reserves resources, returns response information to the BHN through the RESV message, and binds this LSP with the protected P2MP LSP (the binding here refers to the MP Use the path feature information carried in the received Path message to compare with the path feature information of the local existing LSP. If the Session Object and LSP ID are the same, it means that the backup LSP is associated with the protected LSP), and a backup LSP is completed. Establish; when receiving data from the backup LSP, the MP forwards the received data along the subtree with the MP as the root node, and this subtree is a part of the protected P2MP LSP.

For a more detailed process of establishing a point-to-multipoint LSP, refer to the existing standard specification RFC4875.

3. MHN can actively trigger the switching of the head node. In this case, MHN sends a notification message to BHN to tell BHN to switch the head node; The LSP forwards data. BHN can also detect MHN failure through some failure detection mechanisms (such as bidirectional forwarding detection (BFD), fast Hello message); if BHN detects MHN failure, BHN will switch itself as the head node and start to follow the path between BHN and MP. The established LSP forwards data. That is to say, satisfying the head node switching condition may include: the MHN actively triggers the head node switching or the BHN detects that the MHN fails.

When the MHN returns to the working state, the MHN needs to re-establish the P2MP LSP; the specific establishment method can be that the MHN independently establishes the P2MP LSP, or the BHN sends the information used to establish the protected path from the MHN to the MHN to assist The MHN re-establishes the P2MP LSP. Here, the way in which the BHN sends the information for establishing the protected path to the MHN is the same as that in 1.

When the MHN returns to the normal state, the BHN notifies the MHN to switch the head node or the MHN notifies the BHN to actively request to switch back. The established LSP between the MP and MP forwards data. The manner in which the BHN notifies the MHN to switch the head node includes: the BHN directly notifies the MHN to switch the head node; or, the BHN notifies the MHN to switch the head node through the network management.

In the above process of establishing a backup LSP, the SESSION Object carried in the path message is the same. The SESSION Object defines the point-to-multipoint identifier P2MP ID, the point-to-multipoint tunnel identifier P2MPTunnel ID, and the extended tunnel identifier Extended Tunnel ID. The Extended Tunnel ID is required to carry the address of the sender (Ingress LSR). In the embodiment of the present invention, the sender's address is replaced with the P2MP Head Group ID and written into the Extended Tunnel ID.

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

Main head node (MHN), used for forwarding data along the established LSP between MHN and MP;

The backup head node (BHN) is used to establish the backup label switching path LSP from itself to all aggregation nodes MP according to the P2MP Head Group ID. The backup LSP does not include the MHN; Data is forwarded through the established backup LSP between the BHN and the MP.

Satisfying the head node switching condition includes: the MHN actively triggers the head node switching or the BHN detects that the MHN fails.

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

The BHN is also used to notify the MHN to switch the head node after the MHN returns to the normal state. After the switch, the BHN stops forwarding data along the backup LSP established between it and the MP, and the MHN acts as the head node along the It forwards data through the established LSP between it and the MP.

The MHN is also used to notify the BHN head node to switch after the MHN returns to the normal state. After the switch, the BHN stops forwarding data along the backup LSP established between it and the MP, and the MHN acts as the head node along the The established LSP between it and the MP forwards data.

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

The backup LSP establishment unit is used to establish backup LSPs from itself to all MPs according to the P2MP Head Group ID, and the backup LSP does not include the MHN;

The switching unit is used to switch itself as the head node and notify the data transmission unit when the head node switching condition is met;

The data transmission unit is used to forward data along the established backup LSP between the BHN and the MP.

The BHN also includes:

The synchronization unit is used to synchronize the P2MP Head Group ID of the main head node MHN and the backup head node BHN.

Further, the synchronization unit includes:

The sending subunit is used to send the second P2MP Head Group ID to the MHN through a synchronization message;

The receiving subunit is used to receive the first P2MP Head Group ID from the MHN;

The selection subunit is used 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 rules as the MHN.

Alternatively, the synchronization unit includes:

Configuration subunit, used to configure P2MP Head Group ID;

The sending subunit is used to send the P2MP Head Group ID to the MHN through a synchronization message.

The BHN also includes: an information feedback unit, which is used to resend the information from the MHN used to establish the protected path to the MHN, so as to assist the MHN to re-establish the P2MP LSP.

The BHN also includes: a notification unit, which is used to notify the MHN to switch the head node, and then notify the switching unit of the switching information;

A switching unit, configured to switch to a non-head node according to the received notification, and notify the data transmission unit;

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

The embodiment of the present invention also provides a master head node MHN, including:

The LSP establishment unit is used to establish LSPs from the MHN to all MPs;

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

The data transmission unit is used to forward data along the established LSP between the MHN and the MP; after receiving the stop transmission notification from the switching unit, stop forwarding data along the established LSP between the MHN and the MP.

The master head node MHN may also include:

The synchronization unit is used to synchronize the P2MP Head Group ID of the main head node MHN and the backup head node BHN.

The LSP establishment unit is also used to re-establish the P2MP LSP when the MHN returns to the working state.

The switching unit is also used to notify the BHN to switch the head node 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 realized by means of software plus a necessary hardware platform, and of course all can be implemented by hardware, but in many cases the former is better implementation. Based on this understanding, all or part of the contribution made by the technical solution of the present invention to the background technology can be embodied in the form of software products, and the computer software products can be stored in storage media, such as ROM/RAM, magnetic disks, optical disks, etc. , including several instructions to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute the methods described in various embodiments or some parts of the embodiments of the present invention.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications should also be It is regarded as the protection scope of the present invention.

Claims (11)

1. A head node protection method of a point-to-multipoint label switched path, characterized in that the method comprises: The main head node MHN forwards data along the established LSP between the MHN and the aggregation node MP; When the head node switching condition is met, switch to the backup head node BHN, forward data along the backup label switching path LSP, the backup LSP is the label switching path LSP from the BHN to the aggregation node MP, and the backup LSP does not include the primary The head node MHN, the backup label switching path LSP is established according to the P2MP Head Group ID of the point-to-multipoint group identifier. 2. The method according to claim 1, wherein the P2MP Head Group ID is obtained in the following manner: Configure the same P2MP Head Group ID on the MHN and BHN. 3. The method according to claim 1, wherein the P2MP Head Group ID is obtained synchronously by the main head node MHN and the backup head node BHN. 4. method according to claim 3, is characterized in that, described MHN and BHN synchronous P2MP Head Group ID comprises: The MHN sends the first P2MP Head Group ID to the BHN through a synchronization message; The BHN sends the second P2MP Head Group ID to the MHN through 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 synchronous P2MP Head Group ID of the MHN and the BHN comprises: Configure P2MP Head Group ID on the MHN; The MHN sends the P2MP Head Group ID to the BHN through a synchronization message; or, Configure P2MP Head Group ID on the BHN; The BHN sends the P2MP Head Group ID to the MHN through a synchronization message. 6. The method according to any one of claims 1 to 5, wherein the P2MP Head Group ID is the address of the MHN, the address of the BHN, the traffic engineering router identifier TE Router of the MHN One of the ID, the TE Router ID of the BHN, and other globally unique addresses. 7. A head node protection system of a point-to-multipoint label switched path, characterized in that it comprises: The main head node MHN is used to forward data along the established LSP between MHN and MP; The backup head node BHN is used to establish a backup label switching path LSP from itself to the aggregation node MP according to the P2MP Head Group ID. The backup LSP does not include the main head node MHN; when the head node switching condition is met, the BHN switches to the head node , forwarding data along the backup LSP. 8. A backup head node BHN, characterized in that it includes: A backup LSP establishment unit is used to set up backup LSPs from the BHN to all MPs according to the P2MP Head Group ID, and the backup LSPs do not include the MHN; The switching unit is used to switch the BHN as the head node and notify the data transmission unit when the head node switching condition is met; A data transmission unit, configured to forward data along the backup LSP. 9. backup head node BHN according to claim 8, is characterized in that, this BHN also comprises: The synchronization unit is used to synchronize the P2MP Head Group ID of the main head node MHN and the backup head node BHN. 10. The backup head node BHN according to claim 9, wherein the synchronization unit comprises: The sending subunit is used to send the second P2MP Head Group ID to the MHN through a synchronization message; A receiving subunit, configured to receive the first P2MP Head Group ID from the MHN; A selection subunit is used 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. 11. The backup head node BHN according to claim 9, wherein the synchronization unit comprises: Configuration subunit, used to configure P2MP Head Group ID; The sending subunit is configured to send the P2MP Head Group ID to the MHN through a synchronization message.

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