CN112039770A

CN112039770A - Routing method and device

Info

Publication number: CN112039770A
Application number: CN202010888848.8A
Authority: CN
Inventors: 熊学涛; 陈升; 杨海峰; 申成钢
Original assignee: 21VIANET GROUP Inc
Current assignee: 21VIANET GROUP Inc
Priority date: 2020-08-28
Filing date: 2020-08-28
Publication date: 2020-12-04
Anticipated expiration: 2040-08-28
Also published as: CN112039770B

Abstract

The application relates to the technical field of communication, and provides a routing method and a routing device, which are used for solving the problems of high link cost and low network bearing efficiency of a generated path by selecting a route according to a routing priority, wherein the method comprises the following steps: acquiring first state information of an inter-area router in a first area with the ABR and second state information of an intra-area router in a second area with the ABR, wherein the first state information and the second state information both carry address information of a target router; determining a routing rule of the ABR according to the routing identifier carried by the first state information; and according to a routing rule, selecting the next hop route of the ABR from the routers between the areas and the routers in the areas, and generating a path for the ABR to reach the destination router. The ABR determines the routing rule of the ABR according to the first state information of the inter-area router, so that the link overhead can be reduced, and the network bearing efficiency can be improved.

Description

Routing method and device

Technical Field

The application relates to the technical field of communication, and provides a routing method and a routing device.

Background

The Open Shortest Path First (OSPF) is a hierarchical dynamic routing protocol, has the advantages of fast convergence speed of routing change, no routing loop, support of variable-length subnet mask, and the like, and is widely applied to the internet or a data center network at present. The network applying the OSPF protocol can calculate and generate most routers by itself without manually configuring a routing table, and when the topology structure diagram of the network changes, the OSPF protocol can also automatically calculate and correct the forwarding path of the route, thereby greatly facilitating network management.

Each router X running the OSPF protocol in the network performs Shortest path first algorithm (SPF) calculation based on the collected Link State broadcast (LSA), calculates the distance from the router X to each destination router by taking the router X as the root, generates a loop-free tree (also called Shortest path tree) covering the entire network by taking the router X as the root, and constructs a corresponding routing forwarding table according to the generated Shortest path tree. The router X selects a path reaching a destination router according to a Route forwarding table and a Route priority specified by an OSPF protocol, wherein the Route priority order is Intra-Area Route (Intra-Area Route) and Inter-Area Route (Inter-Area Route). In practical application, due to the fact that the network topology is irregular and the bearing capacities of different links are different, link cost of the path is increased sometimes, and the bearing efficiency of the whole network is seriously reduced.

In view of this, the present application provides a new routing method and apparatus.

Disclosure of Invention

The embodiment of the application provides a routing method and a routing device, which are used for solving the problems of high link cost and low network bearing efficiency of a generated path by selecting a route according to a routing priority.

In a first aspect, a routing method provided in an embodiment of the present application is applied to an area border router ABR, and includes:

acquiring first state information of an inter-area router in a first area with the ABR and second state information of an intra-area router in a second area with the ABR, wherein the first state information and the second state information both carry address information of a destination router;

determining a routing rule of the ABR according to the routing identifier carried by the first state information;

and according to the routing rule, selecting the next hop route of the ABR from the routers between the areas and the routers in the areas, and generating a path for the ABR to reach the destination router.

Optionally, the routing identifier is obtained by the following method:

respectively acquiring identification bits of link cost and service type link cost in the first state information;

and determining two identification bits as the routing identification.

Optionally, determining the routing rule of the ABR according to the routing identifier carried by the first state information includes:

if the two identification bits are both 0, taking the routing priority as the routing rule of the ABR;

and if the two identification bits are both 1, taking the link overhead value of the router interface as the routing rule of the ABR.

Optionally, selecting a next hop route of the ABR from the inter-area router and the intra-area router according to the routing rule, including:

if the routing priority is used as the routing rule of the ABR, determining the router in the area as the next hop route of the ABR;

and if the link cost value of the router interface is used as the routing rule of the ABR, the router with the low link cost value is used as the next hop route of the ABR.

In a second aspect, an embodiment of the present application further provides a routing apparatus, which is applied to an area border router ABR, and includes:

the system comprises an acquisition unit, a processing unit and a processing unit, wherein the acquisition unit is used for acquiring first state information of an inter-area router in a first area with the ABR and second state information of an intra-area router in a second area with the ABR, and the first state information and the second state information both carry address information of a destination router;

a determining unit, configured to determine a routing rule of the ABR according to the routing identifier carried by the first state information;

and the routing unit is used for selecting the next hop route of the ABR from the inter-area routers and the intra-area routers according to the routing rule and generating the path of the ABR to the destination router.

Optionally, the routing identifier is obtained by the following method:

and determining two identification bits as the routing identification.

Optionally, the determining unit is configured to:

Optionally, the routing unit is configured to:

In a third aspect, an embodiment of the present application further provides an area border router ABR, including a processor and a memory, where the memory stores program code, and when the program code is executed by the processor, the processor is caused to execute the steps of any one of the routing methods described above.

In a fourth aspect, the present application further provides a computer-readable storage medium including program code for causing an electronic device to perform any one of the steps of the routing method described above when the program product runs on the electronic device.

The beneficial effect of this application is as follows:

according to the routing method and the routing device provided by the embodiment of the application, first state information of an inter-area router in a first area with an ABR (access barring) and second state information of an intra-area router in a second area with the ABR are obtained, and the first state information and the second state information both carry address information of a destination router; determining a routing rule of the ABR according to the routing identifier carried by the first state information; and according to a routing rule, selecting the next hop route of the ABR from the routers between the areas and the routers in the areas, and generating a path for the ABR to reach the destination router. The ABR determines whether to select a route according to the routing priority or select a route according to the link cost according to the first state information of the inter-area router, flexibly adjusts the routing rule according to different application scenes, reduces the link cost and improves the network bearing efficiency.

Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the application. The objectives and other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1a is a schematic diagram of a router of an MA network establishing a neighbor relation with each other;

FIG. 1b is a diagram illustrating the establishment of neighbor relations between DR and BDR of the MA network and other routers;

fig. 2 is a diagram of multiple areas of the MA network;

fig. 3 is a schematic flow chart of ABR routing provided in the embodiment of the present application;

FIG. 4a is a schematic diagram of a first connection relationship among ABRs, inter-area routers, and intra-area routers;

FIG. 4b is a diagram illustrating a second connection relationship between ABRs, inter-area routers, and intra-area routers;

FIG. 5a is a Type3/4LSA packet format specified by the prior art OSPF protocol;

FIG. 5b is a modified Type3/4LSA packet format;

fig. 6 is a schematic structural diagram of a routing device in an embodiment of the present application;

fig. 7 is a schematic structural diagram of an ABR in an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments, but not all embodiments, of the technical solutions of the present application. All other embodiments obtained by a person skilled in the art without any inventive step based on the embodiments described in the present application are within the scope of the protection of the present application.

In a Multiple Access (MA) network operating OSPF, as shown in fig. 1a, assuming that n routers are in total in the MA network and the interfaces of the routers are all in the same network segment, that means n (n-1)/2 neighbor relations are formed in the MA network, maintaining so many neighbor relations consumes additional device resources, flooding and flooding of LSAs among the neighbors are confused, and the same LSAs are duplicated in multiple copies, increasing the flooding number of LSAs in the MA network. In order to solve the above problem, a Designated Router (DR) and a Back-up Designated Router (BDR) are selected in the MA network, and the non-DR and non-BDR routers are called ordinary routers.

As shown in fig. 1b, the DR forms neighbor relations with the non-DR and exchanges link state information, and ordinary routers do not exchange link state information directly, thereby greatly reducing the number of neighbor relations in the MA network and the device resources consumed in exchanging link state information. Once a DR fails, the neighbor relations between the DR and a non-DR are all failed, a Link-State DataBase (LSDB) cannot be synchronized, at this time, the DR needs to be reselected, the neighbor relations between the DR and the non-DR are established, the LSA synchronization is completed, and in order to avoid the risk of single-point failure, the DR and the BDR are simultaneously elected, so that the DR work can be quickly taken over when the DR fails.

After the neighbor relation is established, the common router notifies the LSA of itself to the DR and BDR, and also receives the LSAs of other common routers in the network issued by the DR and BDR, and collects and stores the LSAs generated by itself and the LSAs advertised by the neighbor in its LSDB, so that each router in the MA network can master the topology structure of the whole MA network.

The router X carries out SPF calculation based on the LSDB of the router X, calculates the distance from the router X to each destination router by taking the router X as a root, generates a shortest path tree covering the whole network by taking the router X as the root, and constructs a corresponding routing forwarding table according to the shortest path tree.

According to the OSPF protocol, the MA network is divided into a backbone Area (Area 0) and a normal Area (Area n, n is a positive integer greater than or equal to 1), and each normal Area is directly connected with the backbone Area. As shown in fig. 2, therefore, routers of the entire MA network include an intra-Area Router, a Backbone Router (Backbone Router), an Area Border Router (ABR), and an Autonomous System Border Router (ASBR). Wherein, all interfaces of the router in the area belong to the same OSPF area; at least one interface of the backbone router belongs to a backbone Area, and all routers in the areas in ABR and Area 0 are backbone routers; ABRs are used to connect the backbone area with the common area; the routers that the ASBR uses to exchange routing information with other Autonomous Systems (AS) are called ASBRs.

A router running the OSPF protocol will receive the following four types of LSAs:

(1) the Type 1LSA Network Summary (Network Summary LSA) is an LSA which can be generated by each router and describes the link state and the link cost of the router;

(2) the Type 2LSA network digest is generated by DR;

(3) the Type3/4LSA network abstract is generated by ABR, wherein, the Type 3LSA network abstract describes the route of all network segments in the area and advertises to other related areas, and the Type 4LSA network abstract describes the route to ASBR and advertises to other related areas except the area where the ASBR is located;

(4) the Type 5LSA network digest is generated by the ASBR and describes a route to outside the AS.

In the four types of LSAs described above, the routes generated by the Type 1LSA digest network and the Type 2LSA digest network are referred to as intra-area routes, and the routes generated by the Type 3/4/5LSA digest network are referred to as inter-area routes.

Referring to fig. 3, the ABR routing process in the embodiment of the present application is as follows:

s301: the method comprises the steps of obtaining first state information of an inter-area router located in a first area with an ABR and second state information of an intra-area router located in a second area with the ABR, wherein the first state information and the second state information both carry address information of a target router.

As shown in fig. 4a, the ABR 4, the inter-area router R3 and the intra-area router R6 are in the same area, when R6 accesses an external route, R3 generates a Type3/4LSA network digest, and R6 generates a Type 1LSA network digest, where the Type 1LSA network digest and the Type3/4LSA network digest carry address information of the external route (i.e. an IP address of the external route); then, the inter-area router advertises the Type3/4LSA web digest as first state information to R4, and the intra-area router also advertises the Type 1LSA web digest as second state information to R4.

As shown in fig. 4b, ABR 4 and inter-Area router R3 are in Area 0, ABR 4 and intra-Area router R6 are in Area 1, when R6 accesses an external route (i.e. a destination router), R3 generates a Type3/4LSA network digest, R6 generates a Type 1LSA network digest, and the Type 1LSA network digest and the Type3/4LSA network digest carry address information of the external route; then, the inter-area router advertises the Type3/4LSA web digest as first state information to R4, and the intra-area router also advertises the Type 1LSA web digest as second state information to R4.

S302: and determining the routing rule of the ABR according to the routing identifier carried by the first state information.

Optionally, the process of obtaining the routing identifier from the first state information is as follows:

identification bits Of a link cost (Metric) and a link cost (TOS Metric, Type Of Service Metric) Of the Service Type in the first status information are respectively obtained, and the two identification bits are determined as a routing identification.

In the embodiment of the present application, by modifying the Type3/4LSA packet format of the OSPF protocol, M bits (i.e. identification bits) that can set a routing rule are added, fig. 5a shows the Type3/4LSA packet format specified by the existing OSPF protocol, and fig. 5b shows the modified Type3/4LSA packet format. Specifically, according to the deployment situation of the actual network topology and the carrying capacity of different links, the identification bit of the Type3/4LSA packet format is flexibly set to be 0 or 1.

Therefore, if the two identification bits are both 0, the routing priority is used as the routing rule of the ABR; and if the two identification bits are both 1, taking the link overhead value of the router interface as the routing rule of the ABR.

S303: and according to the routing rule, selecting the next hop route of the ABR from the routers between the areas and the routers in the areas, and generating a path for the ABR to reach the destination router.

Routing rule one: and if the two identification bits are both 0, taking the routing priority as the routing rule of the ABR.

In fig. 4a, R4 is ABR, R3 is inter-area router, R6 is area router, and the routing priority order specified by the OSPF protocol is that the intra-area router, the inter-area router, the first class external router, and the second class external router, respectively, so the next hop route of ABR should be selected as R6. The link overhead values of R3 and R6 are both 1, R6 is selected as the next hop route of ABR, the cross-regional penetration flow can be effectively reduced, the cost of the link is low, and the overall bearing efficiency of the network is high.

Routing rule two: and if the two identification bits are both 1, taking the link overhead value of the router interface as the routing rule of the ABR.

In fig. 4b, the link cost value of R3 is 1 and the link cost value of R6 is 20, so the next hop route of ABR should be R3. Although the selection of R3 cannot reduce the cross-regional penetration traffic, the link overhead value of R3 is much lower than that of R6, and the actual bearer capacity of the link can be fully utilized to optimize the network bearer efficiency.

As shown in fig. 6, which is a schematic structural diagram of a routing device, the device is applied to an area border router ABR, and may include an obtaining unit 601, a determining unit 602, and a routing unit 603, wherein,

an obtaining unit 601, configured to obtain first state information of an inter-area router in a first area with the ABR and second state information of an intra-area router in a second area with the ABR, where the first state information and the second state information both carry address information of a destination router;

a determining unit 602, configured to determine a routing rule of the ABR according to the routing identifier carried in the first state information;

a routing unit 603, configured to select a next hop route of the ABR from the inter-area routers and the intra-area routers according to the routing rule, and generate a path from the ABR to the destination router.

Optionally, the routing identifier is obtained by the following method:

and determining two identification bits as the routing identification.

Optionally, the determining unit 602 is configured to:

Optionally, the routing unit 603 is configured to:

As will be appreciated by one skilled in the art, aspects of the present application may be embodied as a system, method or program product. Accordingly, various aspects of the present application may be embodied in the form of: an entirely hardware embodiment, an entirely software embodiment (including firmware, microcode, etc.) or an embodiment combining hardware and software aspects that may all generally be referred to herein as a "circuit," module "or" system.

In some possible implementations, embodiments of the present application further provide an ABR, which is illustrated in fig. 7, and the electronic device may include at least one processor 701 and at least one memory 702. The memory 702 stores therein program codes, which, when executed by the processor 701, cause the processor 701 to perform the steps of the routing method according to various exemplary embodiments of the present application described above in the present specification. For example, the processor 701 may perform the steps as shown in fig. 3.

In some possible embodiments, the various aspects of the routing method provided by the present application may also be implemented in the form of a program product comprising program code for causing a computer device to perform the steps in the traffic control method according to various exemplary embodiments of the present application described above in this specification when the program product is run on a computer device, for example, the computer device may perform the steps as shown in fig. 3.

The program product may employ any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium include: an electrical connection having one or more wires, a portable disk, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

The program product for traffic control of embodiments of the present application may employ a portable compact disc read only memory (CD-ROM) and include program code, and may be run on a computing device. However, the program product of the present application is not limited thereto, and in this document, a readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with a command execution system, apparatus, or device.

A readable signal medium may include a propagated data signal with readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated data signal may take many forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A readable signal medium may also be any readable medium that is not a readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with a command execution system, apparatus, or device.

Program code embodied on a readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Program code for carrying out operations of the present application may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user computing device, partly on the user equipment, as a stand-alone software package, partly on the user computing device and partly on a remote computing device, or entirely on the remote computing device or server. In the case of remote computing devices, the remote computing device may be connected to the user computing device through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computing device (e.g., through the internet using an internet service provider).

While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims

1. A routing method applied to an Area Border Router (ABR) comprises the following steps:

2. The method of claim 1, wherein the routing identifier is obtained by:

and determining two identification bits as the routing identification.

3. The method of claim 2, wherein determining the routing rule of the ABR according to the routing identifier carried by the first state information comprises:

4. The method of claim 3, wherein selecting the next hop route for the ABR from the inter-area routers and the intra-area routers according to the routing rule comprises:

5. A routing apparatus, applied to an area border router, ABR, comprising:

6. The apparatus of claim 5, wherein the routing identifier is obtained by:

and determining two identification bits as the routing identification.

7. The apparatus of claim 6, wherein the determination unit is to:

8. The apparatus of claim 7, wherein the routing unit is to:

9. An area border router, ABR, comprising a processor and a memory, wherein the memory stores program code which, when executed by the processor, causes the processor to perform the steps of the method of any of claims 1-4.

10. Computer-readable storage medium, characterized in that it comprises program code for causing an electronic device to carry out the steps of the method according to any one of claims 1 to 4, when said program product is run on said electronic device.