WO2013091523A1

WO2013091523A1 - Route backup method and device

Info

Publication number: WO2013091523A1
Application number: PCT/CN2012/086817
Authority: WO
Inventors: 杨东冬; 张旭东
Original assignee: 华为技术有限公司
Priority date: 2011-12-20
Filing date: 2012-12-18
Publication date: 2013-06-27
Also published as: CN103179032B; CN103179032A

Abstract

A route backup method and device are disclosed, and applied in the technical filed of communications. In the method according to an embodiment of the present invention, an alternative node that has already published a multi-source route same as a route of a destination node is first selected; if no intersection node exists on a path from a source node to the destination node and a path from the source node to the alternative node, and the distance from an intermediate node, on the path from the source node to the alternative node, to the alternative node is shorter than the distance from the intermediate node through the source node to the destination node, a route from the source node to the alternative node is used as a backup route from the source node to the destination node. The embodiments of the present invention mainly aim at the case that multiple network nodes publish the same route, and use a low-complexity method to realize multi-source route backup.

Description

The present invention claims the priority of the Chinese patent application filed on December 20, 2011, the Chinese Patent Application No. 201110430171.4, entitled "A Route Backup Method and Apparatus", the entire contents of which is filed on December 20, 2011. This is incorporated herein by reference. Technical field

The present invention relates to the field of communications technologies, and in particular, to a route backup method and apparatus.

Background technique

The data communication network is mainly carried by the protocol stack of the Internet Protocol (IP). Each IP address marks the exact address of a host in the network. In an IP network, a router acts as a basic network node and assumes the role of transmitting IP packets. Specifically, in the process of transmitting IP packets, the router queries the local IP routing table for the corresponding IP packet address. Interface, and then send the IP packet from this outbound interface.

The Internal Gateway Protocol (IGP) is the most commonly used routing protocol in IP networks, including Open Shortest Path First (OSPF), Intermediate System to Intermediate System. Routing Protocol, IS-IS), and Routing Information Protocol (RIP). When the network topology changes, such as a link failure, each network node needs to re-implement the routing protocol interaction to generate a new routing table, that is, the route convergence process.

The existing methods of the Fast Reroute (FRR) are mainly: The backup route is generated according to a certain algorithm before the link is faulty, and the information of the backup route is sent to the IP routing table of the router for storage in advance. When a fault occurs, the router directly forwards the IP packets using the information of the backup routes in the IP routing table to ensure that the service packets are forwarded without interruption. When the backup route is generated, the route routing method of Partial Routes Calculation (PRC) may be used, or the backup route may be determined by a method such as Loop-Free Alternates (LFA). The PRC method is mainly based on a network node, and the routes advertised by each network node (a network node may issue multiple routes) are organized, so that the path to the destination network node, that is, the shortest path preference is known. The calculation of the Shortest Path First (SPF), the backup route to the destination route inherits the backup route to the destination network node; and the LFA method is mainly based on the route, which will directly reach the destination route and will not generate a loop. Routing as a backup route.

In the above-mentioned existing PRC method and the LFA method, when routing backup is determined, only different routes are issued for each network node, but in actual applications, multiple network nodes may issue the same route, that is, multi-source routing, existing There is no way to back up multiple source routes in the solution.

Summary of the invention

One aspect of the present invention provides a route backup method and apparatus, which implements backup of multiple source routes. An aspect of the present invention provides a route backup method, including:

Selecting an alternate node that has issued the same multi-source route as the route advertised by the destination node; if there is no intersection node from the source node to the path of the destination node and the candidate node, and from the source node The distance from the intermediate node on the path of the candidate node to the candidate node is smaller than the distance from the intermediate node to the source node to the destination node, and the source node is to the candidate node. The route acts as a backup route from the source node to the destination node.

An aspect of the present invention provides a route backup method, including:

Determining an alternate node to back up the destination node;

If the distance from the source node to the intermediate node on the path of the candidate node to the candidate node is less than the distance from the intermediate node to the source node to the destination node; The route to the candidate node serves as a backup route from the source node to the destination node.

An aspect of the present invention provides a route backup device, including:

An alternative selection unit, configured to select an alternate node that has issued the same multi-source route as the route advertised by the destination node;

a route backup unit, configured to: when there is no intersection on the path of the candidate node selected from the source node to the destination node and the candidate selection unit, and the path from the source node to the candidate node The distance from the intermediate node to the candidate node is smaller than the distance from the intermediate node to the source node to the destination node, and the route from the source node to the candidate node is used as a location A backup route from the source node to the destination node.

An aspect of the present invention provides a route backup device, including:

An alternative determining unit, configured to determine an alternate node that backs up the destination node;

a backup determining unit, configured to: when a distance from an intermediate node on the path from the source node to the candidate node to the candidate node is less than a distance from the intermediate node to the source node to the destination node Routing the source node to the candidate node as the source node to the destination Backup route for the node.

According to the method of an aspect of the present invention, an alternative node that issues the same multi-source route as the route of the destination node is selected first; if there is no intersection node from the source node to the path of the destination node and the candidate node, and the source is The distance from the intermediate node to the candidate node on the path of the node to the candidate node is less than the distance from the intermediate node to the source node and then to the destination node, and the route from the source node to the candidate node is used as the backup from the source node to the destination node. Routes for fast route convergence. In the embodiment of the present invention, the same route is issued for multiple network nodes, and a multi-source route backup is performed by using a method with low complexity.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only 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.

FIG. 1 is a flowchart of a route backup method according to an embodiment of the present invention;

2 is a schematic diagram showing the relationship structure of network nodes organized according to the S PF algorithm in the embodiment of the present invention;

3 is a schematic diagram showing the relationship between network nodes when routing backup is performed according to an embodiment of the present invention;

4 is a schematic structural diagram of a route backup device according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of another route backup device according to an embodiment of the present invention; FIG. 6 is a schematic structural diagram of another route backup device according to an embodiment 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 obvious that the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

The embodiment of the present invention provides a route backup method, which can be applied to a backup of a path from a source node to a destination node by a device such as a network management device or a network node in a scenario where multiple network nodes advertise the same route. The figure is shown in Figure 1, including: Step 101: Select an alternate node that has issued the same multi-source route as the route advertised by the destination node.

It can be understood that each network node can advertise at least one route that is directly reachable by itself, that is, a local route; and multiple network nodes may advertise the same route, that is, a multi-source route, which may occur at a network node at the boundary of the IGP domain, mainly Since the IGP domain is invisible to the IGP domain, multiple network nodes at the edge of the IGP domain may advertise routes outside the IGP domain as their own routes, thus generating multi-source routes. When a network node advertises a route, it can advertise information such as the prefix and the cost value that uniquely identifies a route. When multiple network nodes advertise the same route, the route addresses advertised by multiple network nodes are the same, that is, the prefix of the route is the same, but Other information posted, such as cost values, may be different.

When selecting an alternate node, the routing backup device may first organize the routes advertised by each network node by using the SPF method, and then select an alternate node among the various network nodes of the organization, specifically when the organization is performed according to the SPF method, the routing backup device is You can use "route" as the base point to organize all network nodes that have published the same route. On the other hand, based on the "network node", all the routes advertised by one network node are organized together. Information about multiple network nodes that advertise the same route.

Specifically, when performing backup calculation on the route from the source node to the destination node, the candidate node may be selected according to the information of the same route advertised by each network node. For example, the route advertised by the destination node may be the same. Among the multiple network nodes of the multi-source route, the network node with the smaller cost value of the multi-source route is selected as the candidate node.

For example, as shown in Figure 2, after the organization of the SPF method, it can be seen that among nodes A, B, C, and D, node A is the root node, node B issues three routes bl to b3, and node C issues three routes. From cl to c3, node D issues three routes dl to d3, and nodes B, C, and D both issue the same route 10.0.0.0/24, which is a multi-source route. If Node B is the destination node, Node C or Node D can be selected as the candidate node.

Step 102: If there is no intersection node from the source node to the path of the destination node and the candidate node respectively, and the distance from the source node to the intermediate node of the candidate node to the candidate node is smaller than the return source from the intermediate node The distance from the node to the destination node, and the route from the source node to the candidate node is used as the backup route from the source node to the destination node.

After the candidate node is selected, it is necessary to determine whether the candidate node can be used as the protection of the destination node, and the following conditions are met: (1) The node with no intersection on the path from the source node to the destination node and the alternate node (except the source node):

For example, from the source node to the destination node through the nodes, b and c, the path from the source node to the candidate node cannot pass through nodes a, b and c, that is, two different network nodes need to have different The next hop node ensures that any network node on the path from the source node to the alternate node does not wrap around the path from the source node to the destination node.

(2) The distance S1 from any one of the intermediate nodes (excluding the source node and the candidate node) on the path from the source node to the candidate node to the candidate node is smaller than the distance S2 from the intermediate node to the source node to the destination node Where S2 is the distance from the intermediate node to the source node and the sum of the distance from the source node to the destination node, ie S S2:

It can be understood that, when a route is advertised, the network node may advertise information such as a prefix and an overhead value for uniquely identifying a route, where the cost value may be information indicating distance, bandwidth, delay, etc., for other network nodes to perform optimally. The calculation of the route. In this embodiment, the routing backup device considers the cost value advertised by each network node in the process of performing the route backup. Specifically, the distance S 1 from the intermediate node to the candidate node in this embodiment may be the intermediate node. The shortest distance to the candidate node, and the sum of the cost values of the multi-source route issued by the candidate node, wherein the multi-source route is the same as the route of the destination node.

The distance from the intermediate node to the destination node to the destination node, S2, is the shortest distance from the intermediate node to the source node, the shortest distance from the source node to the destination node, and the sum of the distribution values of the destination node's published routes.

When the above conditions 1 and 2 are met, the ringless backup can be implemented. The reason for the source node to the candidate node is used as the backup route from the source node to the destination node. The backup of the next hop of the source node is the source node. The next hop of the source node in the alternate node route. After determining the backup route, the route can be quickly converge according to the backup route. Specifically, if the route from the source node to the destination node fails, the route from the source node to the destination node is switched from the source node to the candidate node. routing.

For example, as shown in FIG. 3, the node S is a source node, and the routing table stored in the node S includes a route 10.0.0.10, a next hop node E, and a distance 30 from the node S to the destination node A, which are posted on the destination node A, The distance from the node S to the destination node A is the sum of the shortest distance 20 from the node S to the node A and the cost value 10 of the route 10.0.0.10 issued by the node A, and the shortest distance from the node S to the node A may be the node E. The sum of the cost value of the advertised route 10 and the cost of the route advertised by node A 20; Node B also publishes this route 10.0.0.10, then node S can determine whether node B can act as a protection node for node A, specifically:

For an intermediate node N on the path from the node S to the node B, in this embodiment, the distance S1 from the node N to the node B is the shortest distance 10 from the node N to the node B and the overhead of issuing the route 10.0.0.10 to the node B. The sum 100 of the values 100, and the distance S2 from the node N back to the node S to the node A is the shortest distance 20 from the node N to the node S, the shortest distance 20 from the node S to the node A, and the route A.10.10. The cost value of 10 and 50, because S1 is greater than S2, can not achieve a ringless backup, that is, the path from node S to node B can not be used as a backup path from node S to node A, that is, node N cannot be used as a backup of node S routing.

Assume that the number of network nodes is N, the number of single-source routes is M, and the number of multi-source routes is P. If the number of network nodes that can be backed up is Q, the complexity of routing backup according to the existing LFA algorithm is (M+P). *Q, and the complexity of the multi-source route backup according to the method of the embodiment is P, wherein the complexity may indicate that in the process of performing the route backup calculation, the backup formula is used to determine the number of times of the backup route, and the like. The complexity of performing multi-source route backup by using the method of the embodiment of the present invention is low.

It can be seen that, in the embodiment of the present invention, the candidate node that is the same as the route advertised by the destination node is selected first; if there is no intersection node from the source node to the path of the destination node and the candidate node respectively, and The distance from the intermediate node to the candidate node on the path from the source node to the candidate node is less than the distance from the intermediate node to the source node to the destination node, and the route from the source node to the candidate node is used as the source node to the destination node. Back up routes for fast route convergence. In the embodiment of the present invention, the same route is issued for multiple network nodes, and a multi-source route backup is performed by using a method with low complexity. As a result, the candidate node is selected, and then the candidate node is determined to meet the condition of the acyclic backup. If yes, the backup route is determined. In the embodiment of the present invention, the routing organization algorithm is combined with the determination of the ringless backup. . The embodiment of the invention further provides a route backup method, which is mainly a route backup method for protecting between different network nodes, including:

Step 201: Determine an alternate node that performs backup on the destination node.

When determining the candidate node to back up the destination node, you can choose to have the destination node The same interface or a node that has the same route as the destination node is elected as an alternate node.

Step 202: If the distance from the source node to the alternate node on the path of the candidate node to the candidate node is less than the distance from the intermediate node to the source node and then to the destination node, then the path from the source node to the candidate node is An intermediate node will not return to the path from the source node to the destination node. A ringless backup can be performed, and the route from the source node to the candidate node is used as the backup route from the source node to the destination node.

If the determined candidate node and the destination node issue the same route, the distance from the intermediate node to the candidate node on the path from the source node to the candidate node may be: the shortest distance from the intermediate node to the candidate node, and The candidate node advertises the sum of the cost values of the route; and the distance from the intermediate node to the source node to the destination node can be: the shortest distance from the intermediate node to the source node, the shortest distance from the source node to the destination node, and the destination node release The sum of the cost values of the routes, and so on.

It should be noted that after the backup route is determined, the backup route can be quickly converge according to the backup route. Specifically, if the route from the source node to the destination node fails, the route from the source node to the destination node is switched to the source node. The route to the alternate node.

In the embodiment of the present invention, the candidate node that performs backup on the destination node is first determined, and then the candidate node is determined to meet the condition of the ringless backup. If yes, the backup route is determined, and the route to the different network nodes is implemented. Ring protection. The embodiment of the present invention further provides a route backup device. The structure of the device is as shown in FIG. 4, and includes: an alternative selection unit 10, configured to select an alternate node that has issued the same multi-source route as the route advertised by the destination node;

The routing backup unit 11 is configured to: when there is no intersection on the path from the source node to the destination node and the candidate node selected by the candidate selection unit 10, and from the source node to the candidate node The distance from the intermediate node to the candidate node on the path is smaller than the distance from the intermediate node to the source node to the destination node, and the route from the source node to the candidate node is taken as A backup route from the source node to the destination node.

The distance from any one of the intermediate nodes to the candidate nodes in the path from the source node to the candidate node may be: a shortest distance from the intermediate node to the candidate node, and a sum of the cost values of the multi-source route issued by the candidate node; The distance from the intermediate node to the source node to the destination node may be: the shortest distance from the intermediate node to the source node, the shortest distance from the source node to the destination node, and the sum of the cost values of the route advertised by the destination node. It can be seen that, in the embodiment of the present invention, the candidate selecting unit 10 first selects an alternate node that has the same multi-source route as the route advertised by the destination node; if there is no intersection on the path from the source node to the destination node and the candidate node respectively The node, and the distance from the intermediate node to the alternate node on the path from the source node to the candidate node is less than the distance from the intermediate node to the source node and then to the destination node, then the route backup unit 11 will source the node to the candidate node. The route acts as a backup route from the source node to the destination node. In the embodiment of the present invention, the same route is issued for multiple network nodes, and a multi-source route backup is performed by using a method with low complexity.

Referring to FIG. 5, in a specific embodiment, the route backup device may include a route convergence unit 12 in addition to the structure shown in FIG. 4, and the candidate selection unit 10 may specifically include a node organization unit 110 and Selection unit 120, wherein:

The route convergence unit 12 is configured to: when the route from the source node to the destination node fails, switch the route of the source node to the destination node to be from the source according to the backup route determined by the route backup unit 11. The route of the node to the alternate node.

The node organization unit 110 is configured to organize the routes advertised by the network nodes by using the shortest path preference SPF. After being organized by the node organization unit 110, the information of multiple network nodes that advertise the same route can be obtained intuitively.

The selecting unit 120 is configured to select, among the various network nodes organized by the node organization unit 110, an alternate node that issues the same multi-source route as the route advertised by the destination node.

The selecting unit 120 may be specifically configured to: according to the organization of the node organization unit 110, select, in the plurality of network nodes that have the same multi-source route as the route advertised by the destination node, the cost of issuing the multi-source route is small. The node is used as an alternative node.

In this embodiment, the candidate node is obtained by the organization of the node organization unit 110 and the selection unit 120, and the backup route is determined by the route backup unit 11, and the route convergence unit 12 can perform fast route convergence. The embodiment of the present invention further provides a route backup device. The schematic diagram of the structure is shown in FIG. 6. The method includes: an candidate determining unit 20, configured to determine an alternate node that performs backup on the destination node.

The alternative determining unit 20 may select, as an alternative node, a node having the same interface as the destination node or the same route as the destination node when determining the candidate node to back up the destination node.

A backup determining unit 21 for selecting an alternate node from the source node to the candidate determining unit 20 The distance from the intermediate node on the path to the candidate node is less than the distance from the intermediate node to the source node to the destination node; the route from the source node to the candidate node is taken as A backup route from the source node to the destination node.

If the candidate node determined by the candidate determining unit 20 issues the same route as the destination node, the distance from the source node to the intermediate node on the path of the candidate node to the candidate node may be: from the intermediate node to the candidate node The shortest distance, the sum of the cost of the route issued by the candidate node; and the distance between the intermediate node and the source node to the destination node can be: the shortest distance from the intermediate node to the source node, the shortest distance from the source node to the destination node And the sum of the cost values of the route advertised by the destination node.

The device in this embodiment may further include a convergence unit, configured to: when the route of the source node to the destination node fails, according to the backup route determined by the backup determining unit 21, send the source node to the destination node. The route is switched to a route from the source node to the candidate node. Then, the backup determining unit 21 determines whether the candidate node meets the condition of the ringless backup, and if yes, determines the backup route, so that the route can be quickly converged by the convergence unit, and the routing of the different network nodes is implemented. Ring protection.

The various routing backup devices provided by the embodiments of the present invention may perform corresponding steps in the method embodiments, and details are not described herein again.

A person skilled in the art can understand that all or part of the steps of the foregoing embodiments can be completed by a program to instruct related hardware. The program can be stored in a computer readable storage medium. The storage medium can include: Read only memory (ROM), random access memory (RAM), magnetic or optical disk, and the like.

The method and apparatus for routing backup provided by the embodiments of the present invention are described in detail. The description of the examples is only used to help understand the method and core idea of the present invention. Meanwhile, for those skilled in the art, according to the present invention, The present invention is not limited by the scope of the present invention.

Claims

Rights request

A route backup method, comprising:

The method of claim 1, wherein the selecting the candidate node that has the same multi-source route as the route advertised by the destination node comprises: routing the route advertised by each network node by using the shortest path preferred SPF And selecting, among the various network nodes of the organization, an alternate node that has issued the same multi-source route as the route advertised by the destination node.

The method of claim 2, wherein the selecting the candidate node that has issued the same multi-source route as the route advertised by the destination node comprises:

Among the plurality of network nodes that have issued the same multi-source route as the route advertised by the destination node, the node that advertises the multi-source route with the smaller cost value is selected as the candidate node.

The method according to any one of claims 1 to 3, wherein the distance from the intermediate node on the path from the source node to the candidate node to the candidate node is: a shortest distance from the intermediate node to the candidate node, and a sum of the cost values of the multi-source route issued by the candidate node;

The distance that the intermediate node returns the source node to the destination node is: a shortest distance from the intermediate node to the source node, a shortest distance from the source node to the destination node, and the The destination node advertises the sum of the cost values of the routes.

The method according to any one of claims 1 to 3, further comprising: when a route of the source node to the destination node fails, from the source node to the destination node The route is switched to a route from the source node to the alternate node.

6. A route backup method, characterized in that:

Determining an alternate node to back up the destination node;

7. The method of claim 6, wherein the candidate node and the destination node Publish the same route;

The distance from the intermediate node on the path from the source node to the candidate node to the candidate node is: the shortest distance from the intermediate node to the candidate node, and the cost value of the route advertised by the candidate node with;

The distance that the intermediate node returns to the source node and then to the destination node is: the shortest distance from the intermediate node to the source node, the shortest distance from the source node to the destination node, and the cost of the route advertised by the destination node The sum of the values.

8. The method according to claim 6 or 7, further comprising:

When the route from the source node to the destination node fails, the route from the source node to the destination node is switched to a route from the source node to the candidate node.

9. A route backup device, comprising:

The device according to claim 9, wherein the candidate selection unit comprises: a node organization unit, configured to organize a route issued by each network node by using a shortest path preference SPF;

And a selecting unit, configured to select, in each network node of the node organization unit, an alternate node that has issued the same multi-source route as the route advertised by the destination node.

The device according to claim 7, wherein the selecting unit is configured to, according to the organization of the node organization unit, issue multiple network nodes of the same multi-source route as the route advertised by the destination node. In the middle, the node with the smaller cost value of the multi-source route is selected as the candidate node.

The device according to any one of claims 9 to 11, further comprising: a route convergence unit, configured to: when the route of the source node to the destination node fails, the source node is sent to The route of the destination node is switched to a route from the source node to the candidate node.

13. A route backup device, comprising:

a backup determining unit, configured to: when a distance from an intermediate node on the path from the source node to the candidate node to the candidate node is less than a distance from the intermediate node to the source node to the destination node And routing the source node to the candidate node as a backup route from the source node to the destination node.

14. The device of claim 13, further comprising:

And a convergence unit, configured to: when the route of the source node to the destination node fails, switch the route of the source node to the destination node to a route from the source node to the candidate node.