CN108123876B

CN108123876B - Border gateway protocol BGP routing information processing method and device

Info

Publication number: CN108123876B
Application number: CN201711337834.1A
Authority: CN
Inventors: 谭智
Original assignee: Hangzhou H3C Technologies Co Ltd
Current assignee: Hangzhou H3C Technologies Co Ltd
Priority date: 2017-12-14
Filing date: 2017-12-14
Publication date: 2020-08-11
Anticipated expiration: 2037-12-14
Also published as: CN108123876A

Abstract

The disclosure relates to a method and a device for processing BGP routing information. The method comprises the following steps: when a first router publishes a BGP route to a second router, judging whether a path between the second router and a destination device indicated by the BGP route passes through the first router or not, or judging whether a path between the second router and a next hop device indicated by the BGP route passes through the first router or not; and if the BGP route passes through the first router, carrying the first life cycle attribute to the BGP route issued to the second router. According to the BGP route information processing method and device disclosed by the embodiment of the invention, the survival time of each BGP route can be finely controlled, and different life cycle attributes are set for different BGP routes aiming at different networking conditions, so that flow interruption is avoided or reduced as much as possible.

Description

Border gateway protocol BGP routing information processing method and device

Technical Field

The present disclosure relates to the field of network communication technologies, and in particular, to a method and an apparatus for processing BGP routing information.

Background

BGP (Border Gateway Protocol) is a dynamic routing Protocol that can be used both between different ASs (Autonomous systems) and within the same AS. The currently used version of BGP is BGP-4, and BGP-4 is widely used by ISPs (Internet service providers) as a standard for Internet external routing protocols.

When BGP runs inside the same AS, it is called ibgp (internal BGP); when BGP runs between different ASs, it is called ebgp (external BGP). The AS is a system consisting of a group of routers which have the same routing strategy and belong to the same technical management department.

BGP GR (Graceful Restart) is a mechanism that ensures uninterrupted forwarding service when the active/standby switch or the BGP protocol is restarted.

The GR has two roles:

GR Restarter: and the equipment has GR capability and generates active/standby switching or protocol restart.

GR Helper: and the GR Restarter has a neighbor relation with the GR Restarter, assists the equipment completing the GR process, and the GR Helper also has GR capability.

BGP route attributes are a set of parameters that are published along with the route. BGP route attributes, which further describe specific routes, enable route receivers to filter and select routes according to route attribute values, such as: origin attribute, next hop attribute, etc.

Disclosure of Invention

In view of this, the present disclosure provides a method and an apparatus for processing BGP route information, which may finely control the lifetime of each BGP route, and set different lifetime attributes for different BGP routes according to different networking conditions, so as to avoid or reduce traffic interruption as much as possible.

According to an aspect of the present disclosure, a method for processing BGP routing information is provided, where the method includes:

when a first router publishes a BGP route to a second router, judging whether a path between the second router and a destination device indicated by the BGP route passes through the first router or not, or judging whether a path between the second router and a next hop device indicated by the BGP route passes through the first router or not;

if the BGP route passes through the first router, the BGP route issued to the second router carries a first life cycle attribute;

the aging time determined according to the first life cycle attribute is a first designated value; the first specified value indicates that the second router deletes the BGP route when detecting that the first router is disconnected from the neighbor of the second router.

According to another aspect of the present disclosure, there is provided an apparatus for processing BGP routing information, the apparatus including:

a determining module, configured to determine, when a first router issues a BGP route to a second router, whether a path between the second router and a destination device indicated by the BGP route passes through the first router, or whether a path between the second router and a next-hop device indicated by the BGP route passes through the first router;

the first publishing module is used for publishing the BGP route to the second router to carry a first life cycle attribute if the BGP route passes through the first router;

According to the BGP routing information processing method and device, the survival time of each BGP route can be finely controlled, different survival cycle attributes are set for different BGP routes according to different networking conditions, and therefore flow interruption is avoided or reduced as much as possible.

Other features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments, features, and aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

Fig. 1 illustrates a schematic diagram of an example BGP RR networking scenario.

Fig. 2 illustrates a schematic diagram of applying GR techniques in a BGP RR networking scenario, according to an example.

Fig. 3 shows a flow chart of a routing information processing method according to an example of the present disclosure.

Fig. 4 shows a flow chart of a routing information processing method according to an example of the present disclosure.

Fig. 5 shows a flow chart of a routing information processing method according to an example of the present disclosure.

Fig. 6 shows a block diagram of a routing information processing apparatus according to an example of the present disclosure.

Fig. 7 shows a block diagram of a routing information processing apparatus according to an example of the present disclosure.

Fig. 8 shows a block diagram of a routing information processing apparatus according to an example of the present disclosure.

Detailed Description

Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers can indicate functionally identical or similar elements. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present disclosure. It will be understood by those skilled in the art that the present disclosure may be practiced without some of these specific details. In some instances, methods, means, elements and circuits that are well known to those skilled in the art have not been described in detail so as not to obscure the present disclosure.

When routing is issued in the AS, IBGP connections need to be established between every two network devices, so that when the number of network devices in the AS is large, a large number of IBGP connections exist, and networking scale and network performance are affected. Therefore, the BGP protocol introduces an RR (Route Reflector) mechanism, and all network devices in the AS establish connections only with RR devices, thereby solving the above-mentioned problems. RR is a mature mechanism, and is widely deployed on the existing network, and AS a place for centralized control of BGP routes in an AS, RR devices are expected to be used for centralized control and scheduling of the network, but actual traffic does not necessarily pass through the RR devices.

Fig. 1 illustrates a schematic diagram of an example BGP RR networking scenario. As shown in fig. 1, the scenario includes an RR device and two CR (Client Route) devices CR-1, CR-2, where the CR-1 and CR-2 all establish a neighbor with the RR device, the RR device reflects a Route to the CR-1 and CR-2, and traffic from the CR-1 to the CR-2 is forwarded through a direct connection line between the CR-1 and the CR-2.

The BGP protocol, whose neighbors are established based on TCP connections, specifies that routes learned from a neighbor need to be deleted after the neighbor is disconnected. In the networking shown in fig. 1, when an RR device needs version upgrade or is restarted due to a failure, the neighbor relationship between CR-1 and the RR device and the neighbor relationship between CR-2 and the RR device are disconnected, and CR-1 and CR-2 delete routes learned from the neighbor RR device, which causes traffic interruption. In this case, if the CR device can maintain the route during the restart of the RR device, the interruption of the traffic can be avoided.

Currently, the GR technology is commonly used for this situation, that is, the neighbors of the BGP protocol first negotiate the GR capability of the BGP protocol, for example, which address families support GR, aging time, and the like, and when the device or the BGP protocol is restarted, the peer neighbor device (GR Helper) enters the GR state and marks the routes received from the GR restart device with aging marks. And the neighbor relation is required to be reestablished and the route is required to be reissued within the aging time, and if the GR Helper does not receive the update, the route received from the GR Restarer (restarted device) is deleted.

As shown in fig. 1, when the RR device is restarted, the CR device marks an aging flag on a route learned from the RR device, and during the aging time, if the RR device is restarted and the route is re-issued to the CR device, the CR device does not delete the route, and if the RR device is not restarted or the original route is not issued during the aging time, the CR device deletes the route learned from the RR device. By which uninterrupted flow is achieved.

The above BGP protocol GR technique has the following problems:

the GR capability needs to be negotiated in advance among the neighbors of the BGP protocol, and the GR aging time is negotiated well. After the negotiation of the aging time is completed, the time will take effect on all routes from the neighbor, which may result in the route being retained by mistake and traffic being blocked instead.

Fig. 2 is a diagram illustrating application of GR techniques in an exemplary BGP RR networking scenario, where dashed lines represent neighbor connections (for route advertisement) established between devices, and solid lines represent data interaction links between devices. As shown in FIG. 2, CR-2 receives the route of CR-4 reflected by the RR device and also receives the route of CR-4 issued by CR-1. If CR-2 prefers routing from the RR device, then CR-2 to CR-4 traffic is forwarded through the RR device (CR-2 → RR → CR-4).

When the RR equipment is restarted and the flow forwarding cannot be carried out in the restarting process of the RR equipment, as the CR-2 and the RR equipment negotiate the GR capability, the CR-2 does not delete the route reflected by the RR equipment, so that the flow from the CR-2 to the CR-4 is still forwarded to the CR-4 through the RR equipment, and the flow is interrupted in the aging time.

In order to solve the above technical problem, the present disclosure provides a method for processing routing information, which may be applied to a router based on BGP protocol networking.

Fig. 3 shows a flow chart of a routing information processing method according to an example of the present disclosure. The method can be applied to BGP routers in a network based on BGP protocol networking, such as RR. As shown in fig. 3, the method may include:

step S11, when the first router issues the BGP route to the second router, determining whether a path between the second router and the destination device indicated by the BGP route passes through the first router, or determining whether a path between the second router and the next-hop device indicated by the BGP route passes through the first router.

Taking the networking shown in fig. 2 AS an example, the first router and the second router may be BGP routers located in the same AS, for example, any two BGP routers in AS 200. In one example, the first router is an RR device, the second router may be another BGP router within the AS200 except for the RR device, and the first router may publish a BGP route to the second router, where the BGP route sent by the first router to the second router is hereinafter referred to AS the first BGP route for convenience of description.

In a possible implementation manner, the controller issues a route transmission control policy to the first router, and the first router determines, according to the route transmission control policy, whether a path between the second router and the destination device indicated by the BGP route or a path between the second router and the next hop device indicated by the BGP route passes through the first router. The route sending control policy includes path information corresponding to the BGP route, where the path information indicates information that reaches a destination device indicated by the BGP route from the second router or each node (router) traversed by a next hop indicated by the BGP route.

For example, taking an SDN (Software Defined Network) as an example, an SDN controller may collect Network topology information in a management area, and calculate a path of a BGP route issued by each router in the Network according to the Network topology information, so as to determine a routing control policy.

For example, as shown in fig. 2, the controller collects network topology information, and for a BGP route to be reflected to CR-2 on RR, such as a route to CR-4 (which may refer to that a destination device indicated by the BGP route is CR-4, or that a next hop indicated by the BGP route is CR-4) and a route to CR-3, the controller may calculate, according to the network topology information, that a path corresponding to the route to CR-4 to be reflected to CR-2 on RR is: CR-2 → RR → CR-4; the path on the RR to the route to CR-3 to be reflected to CR-2 can be calculated as: CR-2 → CR-3. According to the calculation result of the network topology information, it can be determined that the route to CR-4 passes through RR and the route to CR-3 does not pass through RR.

The route sending control policy issued by the SDN controller to the RR device may carry path information corresponding to the route, or may also carry information whether the route passes through the RR.

In another example, a Network APP (Network application program) is configured in the controller, the Network APP may collect Network topology information of the management area, and calculate a next hop relationship of the route according to the Network topology information, and the Network APP may communicate with the first router based on a Netconf protocol.

In this example, the first router sends an inquiry request to the controller, so that the controller obtains path information corresponding to the BGP route and returns an inquiry result of whether a path corresponding to the BGP route passes through the first router to the first router according to the path information, in an example, the inquiry request may include a next hop indicated by the BGP route and the second router, and the inquiry request may also include a destination device indicated by the BGP route and the second router; and the first router receives the query result and determines whether the path corresponding to the BGP route passes through the first router according to the query result.

For example, for a BGP route to be reflected to CR-2 in RR, the next hop of the BGP route is CR-4, and the RR device sends an inquiry request to the Network APP to inquire whether a path from CR-2 to CR-4 passes through the RR device, where the inquiry request may include information of the next hop of the route, CR-4 and CR-2. After receiving the query request, the Network APP obtains corresponding path information, for example, the corresponding path information is CR-2 → CR-3 → RR → CR-4, and returns a query result to the RR device according to the path information, for example, the path includes the RR device; and the RR equipment receives the query result and determines that the path from the CR-2 to the CR-4 passes through the RR equipment according to the query result.

For another example, the RR device sends a BGP route of CR-4 to CR-5, where the next hop of the BGP route is CR-4, and the RR device first sends an inquiry request to the Network APP to inquire whether a path from CR-5 to CR-4 passes through the RR device. The network APP obtains corresponding path information after receiving the query request, for example, the corresponding path information is CR-5 → CR-6 → CR-4, and returns a query result to the RR device according to the path information, for example, the path does not include the RR device.

If the traditional network has no special controller to collect the network topology information to calculate the path information corresponding to the route, the routing community attribute is configured statically to distinguish the routing control strategy. As shown in fig. 2, a routing transmission control policy corresponding to the community attribute may be stored on the RR device, for example: community attribute 1000: 1, the BGP route corresponding to the BGP route sends a control strategy to indicate that a path corresponding to the BGP route passes through RR equipment; configuring a BGP route carried community attribute 1000, which is issued by a router (e.g., CR-4) where a path corresponding to a sent BGP route passes through an RR device, on the router: 1. thus, when CR-4 is advertising a CR-4 route to RR devices, the community attribute 1000 is carried in the route: 1, when the RR device reflects the CR-4 route to another device, it may determine, according to the correspondence between the community attribute and the BGP route transmission control policy, that the path corresponding to the CR-4 route issued to the other device passes through the RR device.

The BGP routing configuration policy above is merely an example of the present disclosure, and does not limit the present disclosure in any way, and those skilled in the art may set the BGP routing configuration policy in other ways.

Step S12, if the BGP route passes through the first router, the BGP route issued to the second router carries a first lifetime attribute.

The lifetime attribute may be an attribute for BGP routes that conforms to the route attribute specification of the BGP protocol. The lifetime attribute may include information such as an attribute Type value (Attr Type), an attribute length field (Attr Len), an attribute value (AttrValue), and the like, wherein the attribute Type value may be selected as a non-transferable attribute, the attribute value may include a time attribute, and the time attribute may be a 4-byte or 8-byte field. The value of the time attribute represents aging time of the BGP route, which may represent time for which the BGP route is valid, e.g., if no update of the BGP route is received within the aging time of the BGP route, the BGP route is invalid, the BGP route is valid before that, and the router deletes the BGP route after the BGP route is invalid; if the BGP route is updated within the aging time of the BGP route, the BGP route continues to be effective, and the router does not delete the BGP route.

Specifically, the second router receives the first BGP route, and the second router may determine the aging time of the first BGP route according to the first lifetime attribute carried by the first BGP route, where in an example, the aging time is a first specified value, and the first specified value may be 0, and correspondingly, the aging time of the first BGP route is 0. In this embodiment, the start time of the aging time may be a time when the neighbor connection relationship between the first router and the second router is broken, and at this time, the first specified value may be 0, that is, the second router deletes the BGP route when detecting that the neighbor connection between the first router and the second router is broken. Therefore, the route passing through the first router can be deleted immediately under the condition that the BGP neighbor connection is disconnected, and the flow interruption can be avoided.

The BGP router sets a life cycle attribute for the BGP router according to the published path information of the BGP router, can finely control the life time of each BGP router, and sets different life cycle attributes for different BGP routers according to different networking conditions, thereby avoiding or reducing flow interruption as much as possible.

Fig. 4 shows a flow chart of a routing information processing method according to an example of the present disclosure. As shown in fig. 4, the method may further include:

step S13, if not passing through the first router, the BGP route issued to the second router carries a second lifetime attribute.

The second lifetime attribute and the first lifetime attribute are lifetime attributes carried by the BGP route issued by the first router, and information such as an attribute Type value (Attr Type), an attribute length field (Attr Len), an attribute value (AttrValue), and the like of the second lifetime attribute and the first lifetime attribute may be set to different values according to actual requirements.

Still taking the first BGP route as an example for explanation, the aging time determined according to the second lifetime attribute is a second specified value, and the second specified value indicates that the second router keeps the BGP route valid within a second specified value time after detecting that the neighbor connection between the first router and the second router is disconnected. In one example, the second specified value (i.e., the aging time) is not less than the time required for the first router to resume connection with the second router.

Taking the starting time of the aging time as the time when the neighbor connection relationship between the first router and the second router is broken as an example, since the path corresponding to the first BGP route does not pass through the first router, if the value of the time attribute of the second lifetime attribute is set to be smaller than the time required for the first router and the second router to recover the connection, after the aging time and before the first router and the second router recover the connection, the first BGP route will fail, the second router will delete the first BGP route, and during this period, the traffic forwarded by the second router according to the first BGP route may be interrupted.

And setting the aging time of the first BGP route to be not less than the time required for the first router to recover the connection with the second router, and keeping the first BGP route to be continuously effective before the first router recovers the connection with the second router, so that the second router does not delete the first BGP route, and the second router can still forward the flow according to the first BGP route. In this way, flow disruption may be avoided or reduced as much as possible.

Optionally, the first lifetime attribute and the second lifetime attribute may include a start identifier, where the start identifier indicates: and starting an aging timer when the connection between the first router and the neighbor of the second router is disconnected, wherein the aging timer is used for calculating the aging time of the BGP router issued to the second router by the first router.

Fig. 5 shows a flow chart of a routing information processing method according to an example of the present disclosure. As shown in fig. 5, the method may further include:

step S14, when the connection with the neighbor of the second router is disconnected, the first router sends a route withdraw instruction to the second router, so that the second router deletes the BGP route of the corresponding path passing through the first router.

When the first router needs to be restarted or needs to be disconnected from the neighbor of the second router due to other situations, the first router may also cause the second router to delete the BGP route of which the corresponding path passes through the first router by sending a route withdrawal instruction to the second router. And after receiving the withdrawal instruction sent by the first router, the second router deletes the corresponding BGP route according to the withdrawal instruction no matter whether the BGP route carries the life cycle attribute or not.

In this way, traffic disruption can be avoided or reduced as much as possible also in the case of a broken BGP neighbor connection.

Fig. 6 shows a block diagram of a routing information processing apparatus according to an example of the present disclosure. The apparatus may be applied to any BGP router in a network based on BGP protocol networking, and as shown in fig. 6, the apparatus may include:

a determining module 71, configured to determine, when a first router issues a BGP route to a second router, whether a path between the second router and a destination device indicated by the BGP route passes through the first router, or whether a path between the second router and a next-hop device indicated by the BGP route passes through the first router;

a first distribution module 72, configured to, if the BGP route passes through the first router, send a first lifetime attribute to the BGP route issued by the second router;

Fig. 7 shows a block diagram of a routing information processing apparatus according to an example of the present disclosure. As shown in fig. 7, in a possible implementation manner, the apparatus further includes:

a second publishing module 73, configured to, if the BGP route does not pass through the first router, carry a second lifetime attribute to the BGP route published by the second router;

the aging time determined according to the second life cycle attribute is a second specified value; the second specified value indicates that the second router keeps the BGP route valid for a second specified value of time after detecting that the first router is disconnected from the neighbor of the second router.

In a possible implementation manner, the determining module 71 includes:

an inquiring unit 711, configured to send an inquiring request to the controller, so that the controller obtains the path information corresponding to the BGP route and returns, to the first router, an inquiring result of whether the path corresponding to the BGP route passes through the first router according to the path information.

In one possible implementation, the first lifecycle attribute and the second lifecycle attribute both include a startup identification,

the start-up flag indicates that: the aging timer is started when the first router is disconnected from the second router's neighbors,

wherein the aging timer is used for calculating the aging time of the BGP route issued by the first router to the second router.

In one possible implementation, the apparatus further includes:

a revocation module 74, configured to, when the connection with the neighbor of the second router is disconnected, send a route revocation instruction to the second router by the first router, so that the second router deletes the BGP route of the corresponding path through the first router.

Fig. 8 is a block diagram illustrating an apparatus 900 for BGP routing information processing according to an example embodiment. Referring to fig. 8, the apparatus 900 may include a processor 901, a machine-readable storage medium 902 having stored thereon machine-executable instructions. The processor 901 and the machine-readable storage medium 902 may communicate via a system bus 903. Also, the processor 901 performs the BGP routing information processing method described above by reading machine-executable instructions in the machine-readable storage medium 902 corresponding to the BGP routing information processing logic.

The machine-readable storage medium 902 referred to herein may be any electronic, magnetic, optical, or other physical storage device that can contain or store information such as executable instructions, data, and the like. For example, the machine-readable storage medium may be: a RAM (random Access Memory), a volatile Memory, a non-volatile Memory, a flash Memory, a storage drive (e.g., a hard drive), a solid state drive, any type of storage disk (e.g., an optical disk, a dvd, etc.), or similar storage medium, or a combination thereof.

Having described embodiments of the present disclosure, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein were chosen in order to best explain the principles of the embodiments, the practical application, or technical improvements to the techniques in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for processing BGP routing information is characterized in that the method comprises the following steps:

2. The method of processing BGP routing information according to claim 1, further comprising:

if the first router does not pass through, carrying a second life cycle attribute to a BGP route issued to the second router;

3. The method according to claim 1 or 2, wherein the determining whether the path between the second router and the destination device indicated by the BGP route passes through the first router, or determining whether the path between the second router and the next-hop device indicated by the BGP route passes through the first router comprises:

and the first router sends a query request to the controller so that the controller acquires the path information corresponding to the BGP route and returns a query result whether the path corresponding to the BGP route passes through the first router or not to the first router according to the path information.

4. The BGP routing information processing method of claim 2,

the first lifecycle attribute and the second lifecycle attribute both comprise a start identification,

5. The method of processing BGP routing information according to claim 1, further comprising:

when the connection with the neighbor of the second router is disconnected, the first router sends a route canceling instruction to the second router so that the second router deletes the BGP route of the corresponding path passing through the first router.

6. An apparatus for processing BGP routing information, the apparatus comprising:

7. The BGP routing information processing apparatus of claim 6, wherein the apparatus further comprises:

a second publishing module, configured to, if the BGP route does not pass through the first router, carry a second lifetime attribute to the BGP route published by the second router;

8. The BGP routing information processing apparatus of claim 6 or 7,

the judging module comprises:

and the query unit is used for sending a query request to the controller so that the controller acquires the path information corresponding to the BGP route and returns a query result whether the path corresponding to the BGP route passes through the first router to the first router according to the path information.

9. The BGP routing information processing apparatus of claim 7,

10. The BGP routing information processing apparatus of claim 6, wherein the apparatus further comprises:

and the revocation module is used for sending a route revocation instruction to the second router by the first router when the connection with the neighbor of the second router is disconnected so as to enable the second router to delete the BGP route of the corresponding path passing through the first router.