WO2008145046A1

WO2008145046A1 - A local protection node determining method and a router

Info

Publication number: WO2008145046A1
Application number: PCT/CN2008/070941
Authority: WO
Inventors: Chun Liu; Xinzong Zeng; Xin Lv
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-05-30
Filing date: 2008-05-12
Publication date: 2008-12-04
Also published as: CN101056268A; CN101056268B

Abstract

A local protection node determining method and a router are provided, in which the said local protection node determining method includes receiving the display route object transmitted from the upstream node, and the said display route object comprises a collocating item for setting the local protection node; determination is made whether to set the present node as the local protection node according to the collocating item of the said local protection node. The said router includes a message receiving unit for receiving the display route object transmitted from the upstream node, and the said display route object comprises a collocating item for setting the local protection node; the said router also includes a message processing unit for determining whether to set the router as the local protection node according to the collocating item of the said local protection node.

Description

Local protection node determination method and router

The present application claims priority to Chinese Patent Application No. 200710105840.4, entitled "Method and Router for Implementing Fast Rerouting", filed on May 30, 2007, the entire contents of in.

Technical field

The present invention relates to the field of network communication technologies, and in particular, to a method and a router for determining a local protection node.

Background technique

FRR (Fast Reroute) is a mechanism for forming local protection in a multi-protocol Label Switching Traffic Engineering (MPLS TE). When a certain label switching path (LSP, Label Switch Path) fails. The protection action is performed on the node where the failure is found, and the traffic is rerouted to the protection path, so that the network traffic can be protected to the greatest extent, so that the data transmission is not interrupted. Since the action of directing traffic to the protection path is the local action of the Label Switch Router (LSR), the router that forms the FRR protection and can switch traffic when the fault occurs is called the local protection node (PLR). , Point of Local Repair ) , which is also the head node of the protection path in the FRR application.

Currently, there are two ways to protect fast reroute. One is the Facility Backup method, and the other is the One-to-One Backup. The simple backup mode protects the protected LSP by creating a backup tunnel. The one-to-one backup mode protects the protected LSP by directly creating a backup LSP.

According to the foregoing fast re-routing protection technology, for a protected LSP, if the tunnel requires fast re-routing protection, all the nodes passing along the LSP can be used as a PLR node, so that the protected LSP and a backup tunnel are tied to each other. set. When FRR protection is applied to a protected link, the specific protection policy needs to be configured separately on all the nodes along the path, which brings trouble to the application deployment. That is to say, when configuring a specific protected tunnel, it is impossible to indicate which nodes in the downstream can be used as PLR nodes and which cannot be used as PLR nodes, so that the fast rerouting of the protected links cannot be flexibly set.

Summary of the invention

The embodiment of the invention provides a method for determining a local protection node and a router to solve the configuration. When a specific protected link is used, the local protection node problem on the link is determined and fast re-routing is implemented. To this end, the embodiment provides a method for determining a local protection node, where the method includes: receiving a display route object sent by an upstream node, where the display route object includes setting a configuration item of the local protection node;

Determining whether the current node is a local protection node according to a configuration item of the local protection node.

This embodiment provides a router, including:

a message receiving unit, configured to receive a display routing object, where the display routing object includes a configuration item that sets a local protection node;

a message processing unit, configured to determine, according to a configuration item of the local protection node, whether the router locally protects the node;

And a routing unit, configured to perform fast reroute protection on the protected link that passes the router when the message processing unit determines that the router is a local protection node.

As shown in the foregoing technical solution, the embodiment of the present invention first obtains a display routing object that includes current node information, and the display routing object includes setting a configuration item of the local protection node, and then setting a configuration item of the local protection node according to the display routing object. Determining whether the current node is a local protection node, and performing fast rerouting on the protected label switching path of the current node when the current node is a local protection node. Compared with the prior art, the embodiment of the present invention performs display routing. The information of the object is parsed to determine whether the node passing along the protected tunnel or LSP can act as a PLR node, and perform fast rerouting on the protected label switching path passing through the current node when the node is a PLR node. In this way, traffic can be quickly rerouted when the protected tunnel or LSP fails, thereby maximally protecting network traffic and preventing data transmission from being interrupted.

In addition, the display routing object received by the embodiment of the present invention includes whether the current node is a configuration item of the local protection node, and after parsing the display routing object, it can be known whether the current node is designated as a PLR node, such that It can be pointed out which downstream nodes of the protected LSP or tunnel can be used as PLR nodes and which can not be used as PLR nodes, and can flexibly set fast rerouting of the protected links.

DRAWINGS

1 is a timing diagram of specifying a PLR list at an ingress node or a transit node according to an embodiment of the present invention; FIG. 2 is a flowchart of a method for determining a local protection node according to an embodiment of the present invention; 3 is a schematic diagram of a router according to an embodiment of the present invention.

detailed description

First, the extension of the Resource Resert Protocol (RSVP) is introduced. The display route (ERO, Explicit Route) object carried in the RSVP signaling has a 1-byte reservation. In the embodiment of the present invention, the reserved byte is reserved. The extension is such that each node that the RVSP signaling arrives can identify whether the corresponding ERO object allows the creation of a bypass tunnel or a bypass LSP.

The ERO object described by the RSVP protocol consists of a series of sub-objects. The definition of these sub-objects by the IPv4 protocol family and the IPv6 protocol family can be seen in Table 1 and Table 2.

Table 1

0 7 15 31

L type length IPv4 address

IPv4 address length prefix reserved

Table 2

0 7 15 31

L type length IPv6 address

IPv6 address

The IPv6 address length prefix is reserved. As shown in Table 1 and Table 2, both protocols have a Resvd field. The embodiment of the present invention uses the reserved field as a flag, and sets the first preset value to mark the current node as a PLR node. The second preset value marks the current node as a non-PLR node. For example, when the Resvd field is the first preset value 0x 0, it indicates that it is set as a PLR node, and when the Resvd field is the second preset value OxEE, it indicates that the node is a non-PLR node, and since the field uses the all-zero value by default. Therefore, it will not affect the interoperability of different vendors.

Referring to FIG. 1, FIG. 1 is a sequence diagram of specifying a PLR list at an ingress node and a transit node according to an embodiment of the present invention. In this embodiment, an ingress node, a transit (Transit) node, and an egress (Egress) node are taken as an example. Configure the display route ERO at the ingress node and increase the per-hop of the display route. Can be used as a PLR configuration item, which can determine whether a node passing through a tunnel using the ERO can be a PLR node, and then parse the reserved field in the ERO object, so that a specific tunnel can be specified. FRR protected node. The specific implementation process is shown in Figure 1, including:

On the ingress node, configure each hop of the display route to specify a hop that cannot be used as the local protection node PLR. Configure the primary tunnel. If you need to specify that a node through which the primary tunnel passes cannot be a PLR node, you can use the corresponding configured display. Routing; processing the ERO object, determining whether the node can be used as a PLR according to the ERO object; the ingress node sends a path (PATH) message carrying the ERO object to the downstream node (ie, the transit node in this embodiment), and at the same time, the ingress node If it is determined that the node can be used as a PLR, the device searches for a bypass tunnel (Bypasss Tunnel) for FRR protection, or automatically creates a bypass tunnel for FRR protection; otherwise, the primary tunnel is not FRR protected.

If the transit node receives the PATH message carrying the ERO, it determines whether the local node can be used as the PLR according to the ERO object carried in the message, and then sends the path PATH message carrying the ERO object to the downstream node (ie, the implementation) In the example, if the transit node determines that the node can function as a PLR, it processes the primary tunnel to find a bypass tunnel for FRR protection, or automatically creates a bypass tunnel for FRR protection; otherwise, the primary tunnel does not perform FRR. protection.

If the egress node receives the PATH message carrying the ERO object, the upstream node (ie, the transmission node in this implementation) feeds back a message carrying a reservation (RESV) field; the transmission node goes to the upstream node (ie, the portal in this embodiment) The node) feedback carries the RESV field message.

Referring to FIG. 2, FIG. 2 is a flowchart of a method for determining a local protection node according to an embodiment of the present invention, which specifically includes the following steps:

Step 201: Configure each hop of the route to be displayed at the ingress node, and specify whether to allow it as a PLR node for each hop of the displayed route. The path indicating the route tag is the path between the source node and the destination node, and the display of one hop of the route corresponds to a node through which the path passes.

The following principles need to be followed in setting whether each hop is allowed as a PLR node:

1) The node showing the route passing through is allowed to be set as a PLR node, and the node showing that the route does not pass is not allowed to be set as a PLR node, wherein the node through which the route is displayed is usually called included. ( Include ) node. Nodes that do not pass the display route are often referred to as Exclude nodes, and these Exclude nodes cannot be designated as PLR nodes.

2) For multiple IP addresses of the Include node, if they belong to the same node, you need to ensure that only one IP address is used to specify the node as a PLR node.

Step 202: Configure a link. The link can be a primary tunnel or a protected LSP. Specify whether a node of the link acts as a PLR node by configuring an ERO object. Among them, the primary tunnel is a tunnel that needs to be protected.

Step 203: Extend the ERO object, and use the reserved field of the ERO object as a flag bit to indicate whether each hop of the configured display route can be used as a PLR node. For example, the value of the reserved field is 0x0, indicating that the hop is allowed as the PLR. Node, if the value of the reserved field is OxEE, it means that the hop is not allowed as a PLR node.

Step 204: The configured ERO object is sent to the RSVP signaling by the control plane at the ingress node. RSVP signaling carries this information to all nodes on the tunnel through the ERO object carried in the path (PATH) message to ensure that all downstream nodes can obtain this information.

Step 205: The downstream node processes the received ERO object. The downstream node obtains information corresponding to the node from the ERO object, that is, obtains information corresponding to the ingress node or the transit node.

Step 206: Determine whether the ingress node or the transit node is designated as the PLR. If yes, perform step 207. Otherwise, the RSVP signaling notifies the control plane of the current node that the node does not need to perform FRR protection on the primary tunnel.

The judgment is based on the fact that, in each ERO data of the ingress node or the transit node, if the value of the reserved field is 0x0, the node is set as a PLR node; if the value of the reserved field is OxEE, the node is a non-PLR node; If multiple ERO data and the ingress node or the transit node are allowed to conflict as a PLR node, the judgment is considered invalid, that is, the node is allowed as the PLR (ie, the default setting), and the Path Err message is not sent upstream.

That is to say, when the Ingress or Transit node processes the ERO, RSVP will find the local nodes in the ERO, and perform processing such as deleting and further forwarding. When a node belonging to the local is found, it is judged whether the local node is specified not to be a PLR. The judgment is based on the fact that, in each ERO data belonging to the local node, if the value of the Resvd field is all 0x0, it indicates that it is allowed as a PLR node. If the value of the Resvd field is all OxEE, it means that it is not allowed as a PLR node; In the ERO data is Whether the PLR node is allowed to conflict (that is, the value of the reserved field of multiple local ERO data is not all 0x0 or ΟχΕΕ), the judgment is considered invalid, that is, the node is allowed as the PLR (default), and is not sent upstream. Path Err message. If the local node is specified not to be a PLR, the RSVP signaling protocol will inform the control plane that FRR protection is not allowed for the primary tunnel.

When the ERO object is processed by the RSVP signaling at the egress node, it is not necessary to determine whether the local node is set as the PLR.

Step 207: After setting the PLR node as the PLR node, the current node searches for or creates a bypass tunnel for FRR protection, or finds or creates a bypass LSP for the protected LSP to perform FRR protection.

On the nodes through which all the tunnels pass (except the egress node), the control plane of the current node determines whether the protected tunnel and the protection tunnel form an FRR protection relationship, or triggers the automatic creation of a protection tunnel or protection of the LSP. The conditions for determining are as follows:

1) Determine whether the current node is allowed to act as a PLR node by signaling the processing result of the ERO object. If not allowed, the FRR protection relationship is not formed.

2) Whether the protection tunnel overlaps with the protected tunnel. If there is a coincidence, the FRR protection relationship is not allowed.

3) If there are multiple protection tunnels available, choose the optimal path based on the path and bandwidth.

In addition, those skilled in the art can understand that all or part of the steps of implementing the foregoing embodiments may be completed by a program indicating related hardware, and the program may be stored in a computer readable storage medium, where the program is When executed, the following steps are included:

Receiving a display routing object, where the display routing object includes a configuration item for setting a local protection node; parsing a configuration item of the local protection node in the display routing object, and setting whether the current node is a local protection node;

When the current node is set as a local protection node, fast reroute protection is performed on the protected link passing through the current node.

The storage medium may be a ROM, a RAM, a magnetic disk or an optical disk, or the like.

The embodiment of the present invention further provides a router, where the router includes: a message receiving unit 302, a message processing unit 304, and a routing unit 305, and may further include: a message configuration unit 301 and a message sending unit 302. The message configuration unit 301 is configured to configure a display routing object, and set whether it is a configuration item of the local protection node in the display routing object, that is, whether each node on the link is a configuration item of the local protection node, and Carrying a configuration item of the local protection node by displaying a reserved field of the routing object;

The message sending unit 302 is configured to send the display routing object configured by the message configuration unit to all the downstream nodes on the tunnel by using the path message; that is, sending the message configured by the message configuration unit to other nodes connected to the current node through the link. The message is a Resv message, where the message includes a display route object, and the display route object carries a local protection node configuration message;

a message receiving unit 303, configured to receive a display routing object, where the display routing object includes a configuration item that sets a local protection node;

The message processing unit 304 is configured to determine, according to the configuration item of the local protection node, whether the router is a local protection node. Parsing a configuration item of the local protection node in the received display routing object, and setting whether the current node is a local protection node according to the parsing result;

The routing unit 305 is configured to perform fast reroute protection on the protected link that passes the router when the message processing unit determines that the router is a local protection node, and specifically includes:

a lookup creation unit 306, configured to find or create a bypass tunnel for the protected tunnel, and to find or create a bypass label switched path for the protected label switched path;

The switching unit 307 is configured to switch the protected tunnel that passes the current node to the discovered bypass tunnel according to the search result of the lookup creating unit 306, and switch the protected label switching path that passes the current node to the side according to the search result. a label label switching path; or for switching a protected tunnel through the current node to the created bypass tunnel, and switching a protected label switching path through the current node to the created bypass label Exchange path.

It can be seen from the foregoing that the embodiment of the present invention first obtains a display routing object including current node information, and then parses the display routing object, and when the current node is designated as a local protection node, the protected label passing the current node is The switching path performs fast re-routing. Compared with the prior art, the embodiment of the present invention can determine whether the node passing along the protected tunnel or the LSP can act as a PLR node by parsing the information of the displayed routing object, and When the node is a PLR node, the device performs fast rerouting on the protected label switching path of the current node, so that the traffic can be quickly rerouted when the protected tunnel or LSP fails, thereby maximizing protection. Network traffic, and data transmission is not interrupted.

In addition, the embodiment of the present invention configures whether the node through which the route passes and the node that passes through is configured as a local protection node, and then expands the ERO object carried by the RSVP signaling protocol, and displays the route according to the configuration information. The object indicates whether the node through which the route passes is a local protection node, so that the embodiment of the present invention can specify a node that needs FRR protection for a specific tunnel or a protected LSP.

The foregoing description of the method and the router for determining the local protection node provided by the embodiment of the present invention is only for helping to understand the method and core idea of the present invention. Meanwhile, for those skilled in the art, according to the present invention, The scope of the present invention is not limited by the scope of the present invention.

Claims

Rights request

A method for determining a local protection node, the method comprising: receiving a display route object sent by an upstream node, where the display route object includes setting a configuration item of a local protection node;

The method for determining a local protection node according to claim 1, wherein the configuration item of the local protection node comprises: a reserved field for displaying a routing object.

The method for determining a local protection node according to claim 2, wherein the step of determining whether the current node is a local protection node includes:

If the value of the reserved field of each display route object received by the current node is the first preset value, it is determined that the current node is a local protection node;

If the value of the reserved field of each display route object received by the current node is the second preset value, it is determined that the current node is a non-local protection node;

If the value of the reserved field of the plurality of display route objects received by the current node is not all the first preset value or the second preset value, it is determined that the current node is a local protection node, and the path error message is not sent to the upstream node.

The method for determining a local protection node according to claim 3, wherein the method further comprises:

The method for implementing fast re-routing according to claim 4, wherein the step of performing fast re-routing on the protected label switching path of the current node includes:

A bypass link is found or created for the protected link, and the bypass link is formed into a fast rerouting relationship with the protected link.

The method for determining a local protection node according to any one of claims 1 to 5, wherein the method further comprises:

On the upstream node, configure the display route object, and set whether it is the configuration item of the local protection node in the display route object;

The configured display route object is sent to all downstream nodes on the tunnel through the path message.

The method for determining a local protection node according to claim 6, wherein the condition that the configuration shows that the routing object needs to be satisfied is:

The node showing the route passing through is allowed to be set as the local protection node, and the node showing that the route does not pass is not allowed to be set as the local protection node;

For multiple IP addresses showing the nodes through which the route passes, if they belong to the same node, it is guaranteed to use only one IP address to specify the node as a local protection node.

8. A router, comprising:

The router according to claim 8, wherein the router further comprises: a message configuration unit configured to configure a display route object, and set whether the configuration item of the local protection node is in the display route object;

And a message sending unit, configured to send the display route object configured by the message configuration unit to all downstream nodes on the tunnel by using a path message.

10. The router according to claim 8, wherein the routing unit comprises: a lookup creating unit, configured to find or create a bypass tunnel for the protected tunnel, and find or create a protected label switched path. Bypass label switching path;

a switching unit, configured to switch the protected tunnel that passes the current node to the discovered bypass tunnel according to the search result, and switch the protected label switching path that passes the current node to the bypass label switching path according to the search result; or And for switching a protected tunnel through the current node to the created bypass tunnel and switching a protected label switched path through the current node to the created bypass label switched path.