CN106301840B

CN106301840B - Method and device for sending Bidirectional Forwarding Detection (BFD) message

Info

Publication number: CN106301840B
Application number: CN201510280107.0A
Authority: CN
Inventors: 陈晓; 唐建娟; 樊永波
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2015-05-27
Filing date: 2015-05-27
Publication date: 2020-09-15
Anticipated expiration: 2035-05-27
Also published as: CN106301840A; WO2016187979A1

Abstract

The invention provides a method and a device for sending Bidirectional Forwarding Detection (BFD) messages, wherein the method comprises the following steps: when a Bidirectional Forwarding Detection (BFD) session is established, a line card in a distributed system analyzes the type of a received BFD message; the line card activates a timer corresponding to the type; and when the timer is overtime, the line card sends a BFD message corresponding to the timer to a main control in the distributed system. The invention solves the problem that the processing of BFD messages in the related technology is easy to generate error processing, and fills the blank of the related technology.

Description

Method and device for sending Bidirectional Forwarding Detection (BFD) message

Technical Field

The invention relates to the field of communication, in particular to a method and a device for sending Bidirectional Forwarding Detection (BFD) messages.

Background

The Bidirectional Forwarding Detection (BFD) protocol provides a universal standardized media independent and protocol independent fast failure Detection mechanism.

BFD establishes a session on two network devices for detecting a bidirectional forwarding path between the network devices to serve upper layer applications. BFD does not have a neighbor discovery mechanism by itself, but relies on the upper layer application being served to inform its neighbor information to establish a session. After the session is established, the detection message can be periodically and quickly sent, if the BFD message is not received in the detection time, the bidirectional forwarding path is considered to have a fault, and the upper layer application to be served is informed to carry out corresponding processing.

When BFD works normally, the state of conversation is UP, which means that the link is in stable state. When the BFD session is in the UP state, the detection message is sent according to the configured interval. When the devices of both sides receive the BFD detection message, the detection time timer is reset, and the state of session UP is maintained. If the BFD detection message is not received within the detection time, the link is considered to be possibly failed, and the BFD session is migrated to a DOWN state.

The BFD needs to be configured on two devices, which are assumed to be a and B, respectively, and currently keep the UP state normally. When the user deletes the session operation on the B device, the following two events occur simultaneously:

1. the device B immediately stops sending the detection message;

2. when deleting the session, the device B sends a BFD control packet with a state value set to ADMINDOWN to the device a. The message is a protocol message and aims to inform the equipment A to delete the session; after receiving the message, the device A can directly delete the BFD session.

Assuming that the detection time of the device a and the device B BFD is t1, since the device B stops sending the detection message immediately when deleting, if the device a does not receive the detection message sent by the device B within the time t1, the device a BFD will report detection DOWN. Meanwhile, the device B sends an ADMINDOWN protocol packet to the device a, and the time for the device a to receive the packet for processing and delete the BFD is t 2. If t1> t2 and ADMINDOWN is processed first, the session can be deleted normally without any problem; if t1< t2, the BFD will consider to detect DOWN, consider that the link is failed, and when the BFD is associated with the service, it will quickly switch the traffic to the backup link. Therefore, when deleting the remote session, if the message such as ADMINDOWN is not processed quickly, the processing efficiency is improved, and the active/standby link is switched by mistake when the link has no fault.

In a distributed architecture, devices are divided into a master control and line cards, fig. 1 is a schematic diagram of BFD sessions of the master control and the line cards in the related art, as shown in fig. 1, protocol stacks are built on the master control, and the master control is also responsible for management of all online line cards; and the line card is responsible for receiving and sending messages. The line card receives the message from the port, the resolver analyzes the message into a protocol message, the protocol message needs to be sent to the main control to be processed, and the BFD keep-alive message is sent to the BFD timer to be processed. Under the condition of more network configuration, the main control often encounters the condition that the CPU is busy, often processes other protocols with higher priority, or manages other line cards, often cannot process BFD protocol messages in real time, and cannot timely notify the line cards to delete BFD sessions. If the session cannot be deleted in time in response to the ADMINDOWN message of the BFD, and the BFD report detection DOWN is generated after the detection period is exceeded, false switching may be caused. This situation is often present in networks with high network reliability requirements, and is more likely to occur when the BFD detection period configuration is generally short.

Therefore, when the BFD messages are processed in the manner of the upload master control processing in the related art, it cannot be guaranteed that the corresponding BFD messages are processed correctly in time, and miscut is likely to occur. In view of the above problems in the related art, no effective solution has been proposed.

Disclosure of Invention

The invention mainly aims to provide a method and a device for sending Bidirectional Forwarding Detection (BFD) messages, so as to at least solve the problem that the BFD messages are easy to be processed by mistake in the related technology.

According to an aspect of the present invention, a method for sending a Bidirectional Forwarding Detection (BFD) packet is provided, which includes: when a Bidirectional Forwarding Detection (BFD) session is established, a line card in a distributed system analyzes the type of a received BFD message; the line card activates a timer corresponding to the type; and when the timer is overtime, the line card sends a BFD message corresponding to the timer to a main control in a distributed system.

Further, the BFD packet types include: and deleting the ADMINDOWN message of the BFD session and other messages except the ADMINDOWN message.

Further, when the packet is the adminindown packet, the activating, by the line card, a timer corresponding to a specified packet in the type includes: and the line card activates a first timer corresponding to the ADMINDOWN message, wherein the timing time of the first timer is less than the timing time of a second timer corresponding to other messages except the ADMINDOWN message.

Further, before the line card sends a BFD packet corresponding to the timer to a master in a distributed system, the method further includes: and masking the second timer.

Further, when the timer is overtime, the sending, by the line card to the master control in the distributed system, the BFD packet corresponding to the timer includes: and when the first timer is overtime, the line card sends the ADMINDOWN message to a master control in the distributed system.

According to another aspect of the present invention, there is provided a bidirectional forwarding detection BFD packet sending apparatus, where a line card in a distributed system includes: the analysis module is used for analyzing the type of the received BFD message when the Bidirectional Forwarding Detection (BFD) session is established; an activation module for activating a timer corresponding to the type; and the sending module is used for sending the BFD message corresponding to the timer to a main control in the distributed system when the timer is overtime.

Further, when the message is the ADMINDOWN message; the activation module is further configured to activate a first timer corresponding to the ADMINDOWN packet, where a timing time of the first timer is less than a timing time of a second timer corresponding to a packet other than the ADMINDOWN packet.

Further, before the line card sends the BFD packet corresponding to the timer to a master in a distributed system, the apparatus further includes: and the shielding module is used for shielding the second timer.

Further, the sending module is further configured to send, by the line card, the advertise packet to the master in the distributed system when the first timer is overtime.

In the invention, when the Bidirectional Forwarding Detection (BFD) session is established, the type of the received BFD message is analyzed according to the line card in the distributed system, the timer corresponding to the message type is activated, and when the corresponding timer times out, the line card sends the BFD message corresponding to the timer to the main control in the distributed system, thereby solving the problem that the processing of the BFD message in the related technology is easy to generate error processing and filling the blank of the related technology.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

fig. 1 is a schematic diagram of a master and line card BFD session in the related art;

fig. 2 is a flowchart of a method for sending Bidirectional Forwarding Detection (BFD) packets according to an embodiment of the present invention;

fig. 3 is a block diagram of a transmitting apparatus for bidirectional forwarding detection BFD messages according to an embodiment of the present invention;

fig. 4 is a block diagram of an alternative structure of a bidirectional forwarding detection BFD packet sending apparatus according to an embodiment of the present invention;

FIG. 5 is a system framework diagram for improving the false DOWN at BFD deletion resulting in a miscut, according to an alternative embodiment of the present invention;

figure 6 is a flow diagram of a method of improving BFD deletion misconnection due to DOWN false positives, resulting in misconnections, according to an embodiment of the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

This embodiment provides a method for sending Bidirectional Forwarding Detection (BFD) messages, and fig. 2 is a flowchart of the method for sending Bidirectional Forwarding Detection (BFD) messages according to the embodiment of the present invention, as shown in fig. 2, the method includes the steps of:

step S202: when a Bidirectional Forwarding Detection (BFD) session is established, a line card in a distributed system analyzes the type of a received BFD message;

step S204: the line card activates a timer corresponding to the type;

step S206: and when the timer is overtime, the line card sends a BFD message corresponding to the timer to a main control in the distributed system.

Through steps S202 to S206 in this embodiment, when a bidirectional forwarding detection BFD session is established, the type of the received BFD packet is analyzed according to the line card in the distributed system, and the timer corresponding to the packet type is activated, and when the corresponding timer times out, the line card sends the BFD packet corresponding to the timer to the master controller in the distributed system, thereby solving the problem that the processing of the BFD packet in the related art is prone to be processed by mistake, and filling the blank in the related art.

The obtaining of the BFD packet type in this embodiment may include: and deleting the ADMINDOWN message of the BFD session and other messages except the ADMINDOWN message.

When the packet is an adminindown packet, the line card in step S204 of this embodiment activates the timer corresponding to the specified packet in the type, which may be implemented in an optional implementation manner of this embodiment as follows: and the line card activates a first timer corresponding to the ADMINDOWN message, wherein the timing time of the first timer is less than the timing time of a second timer corresponding to other messages except the ADMINDOWN message.

That is to say, when there is an ADMINDOWN packet in the BFD packet, the first timer corresponding to the ADMINDOWN packet is activated, and since the timing time of the first timer is shorter than the timing time of the second timer corresponding to other packets except the ADMINDOWN packet, the ADMINDOWN packet can be processed in time, and the master control is notified to delete the BFD session.

In order to better and timely process the ADMINDOWN packet, in another optional implementation manner of this embodiment, before the line card sends the BFD packet corresponding to the timer to the master in the distributed system, the method of this embodiment may further include: the second timer is masked. By the mode, the second timer is prevented from being overtime, and the ADMINDOWN message can be processed in time.

Optionally, as for the manner in which, in step S206 in this embodiment, when the timer is overtime, the line card sends the BFD packet corresponding to the timer to the master in the distributed system, the following manner may be implemented: and when the first timer is overtime, the line card sends an ADMINDOWN message to the master control in the distributed system.

In this embodiment, a sending device for bidirectional forwarding detection BFD packet is further provided, where the sending device is used to implement the foregoing embodiments and optional embodiments, and details are not repeated for what has been described. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated.

Fig. 3 is a block diagram of a transmitting apparatus for bidirectional forwarding detection BFD packet according to an embodiment of the present invention, and as shown in fig. 3, the apparatus is located in a line card in a distributed system, and the apparatus includes: the analyzing module 32 is configured to analyze the type of the received bidirectional forwarding detection BFD packet; an activation module 34 coupled to the parsing module 32 for activating a timer corresponding to the type; and a sending module 36, coupled to the activating module 34, configured to send, when the timer is overtime, a BFD packet corresponding to the timer to a master in the distributed system.

Optionally, the BFD packet includes: and deleting the ADMINDOWN message of the BFD session and other messages except the ADMINDOWN message.

Optionally, when the packet is an adminindown packet, the activating module 34 is further configured to activate a first timer corresponding to the adminindown packet, where a timing time of the first timer is less than a timing time of a second timer corresponding to a packet other than the adminindown packet.

Optionally, the sending module 36 is further configured to, when the first timer is overtime, send an advertise message to the master in the distributed system by the line card.

Fig. 4 is a first optional structural block diagram of a sending apparatus for bidirectional forwarding detection BFD messages according to an embodiment of the present invention, and as shown in fig. 4, before a line card sends a BFD message corresponding to a timer to a master in a distributed system, the apparatus further includes: and a shielding module 42 coupled to the transmitting module 36 for shielding the second timer.

The invention will be illustrated below with reference to alternative embodiments thereof;

fig. 5 is a system framework diagram of a miscut caused by a false DOWN alarm when BFD is deleted according to an alternative embodiment of the present invention, and as shown in fig. 5, the system includes:

the parser 501 is configured to enter the parser to parse the message after the message reaches the line card interface, and parse the type of the message to perform different processing on the message. The parser 501 can parse out a normal BFD detection packet and a BFD ADMINDOWN packet.

The BFD timer 502 is configured to be created when a BFD session is established, and each common detection packet analyzed by the analyzer 501 is sent to the BFD timer 502 for operations such as resetting.

The ultra-short timer 503 is configured to activate the ultra-short timer 503 when the parser 501 parses out the packet that is ADMINDOWN, and at this time, the ultra-short timer starts to count time immediately, where the time of the ultra-short timer is far shorter than that of the BFD timer. Since the time is much shorter than the BFD timer, it may timeout immediately. The BFD timer 502 is masked while the ultra-short timer 503 is activated.

The master protocol stack 504 is configured to notify the master protocol stack after the ultra-short timer 503 times out, and the master protocol stack may issue a delete operation of the line card.

Fig. 6 is a flowchart of a method for improving the false DOWN at BFD deletion resulting in false cut, as shown in fig. 6, the method comprising the steps of:

step S602: analyzing the message; when the analyzed message is an ADMINDOWN message, executing step S604, and when the analyzed message is other common messages, executing step S612;

after the message reaches the line card interface, the type of the message is analyzed, and different processing is performed on the message. The module needs to be capable of analyzing a common BFD detection message and a BFD ADMINDOWN message;

step S604: analyzing a BFD ADMINDOWN message to activate an ultra-short timer;

step S606: masking the BFD timer to prevent the BFD timer from timing out;

step S608: after the activated ultrashort timer is overtime, the master control protocol stack is informed to delete the session;

step S610: completing the ultrashort timer task;

step S612: BFD normally detects the message;

step S614: the BFD timer is shielded, and no operation is performed after timeout;

step S616: and finishing the common process.

In the related technology, the protocol message is sent to the main control, and is sent down by the BFD protocol stack of the main control to be deleted. In this alternative embodiment, the message is not required to be sent to the master protocol stack for processing, but the special protocol message is directly processed on the line card. The protocol stack does not need to be established on the line card, but another timer (corresponding to the first timer) with a shorter period is created in addition to the BFD session timer (corresponding to the second timer) that should be created at the time of session creation, and the time setting of the timer is far lower than the detection period of the session itself. When the line card receives the BFD message, the ADMINDOWN message is analyzed by the analyzer, the timer is activated, and the timer of the original session is shielded, so that the DOWN cannot be misreported by the original session, and the protocol layer is notified to delete the session when the timeout event of the ultrashort timer occurs.

In another embodiment, a software is provided, which is used to execute the technical solutions described in the above embodiments and preferred embodiments.

In another embodiment, a storage medium is provided, in which the software is stored, and the storage medium includes but is not limited to: optical disks, floppy disks, hard disks, erasable memory, etc.

It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

The above description is only an alternative embodiment of the present invention and is not intended to limit the present invention, and various modifications and variations of the present invention may occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for sending Bidirectional Forwarding Detection (BFD) messages is characterized by comprising the following steps:

when a Bidirectional Forwarding Detection (BFD) session is established, a line card in a distributed system analyzes the type of a received BFD message, wherein the type of the BFD message comprises: the ADMINDOWN message and other messages except the ADMINDOWN message are used for deleting the BFD session;

the line card activates a timer corresponding to the type, and when the packet is the adminnew packet, the line card activates the timer corresponding to a specified packet in the type, including: the line card activates a first timer corresponding to the ADMINDOWN message, wherein the timing time of the first timer is less than the timing time of a second timer corresponding to other messages except the ADMINDOWN message;

and when the timer is overtime, the line card sends a BFD message corresponding to the timer to a main control in a distributed system.

2. The method according to claim 1, wherein before the line card sends a BFD packet corresponding to the timer to a master in a distributed system, the method further comprises:

and masking the second timer.

3. The method according to claim 2, wherein when the timer expires, the line card sending a BFD packet corresponding to the timer to a master in a distributed system comprises:

and when the first timer is overtime, the line card sends the ADMINDOWN message to a master control in the distributed system.

4. The utility model provides a two-way transmission detects sender of BFD message which characterized in that, the line card that is arranged in distributed system surveys, includes:

the analysis module is used for analyzing the type of the received BFD message when the Bidirectional Forwarding Detection (BFD) session is established, wherein the type of the BFD message comprises: the ADMINDOWN message and other messages except the ADMINDOWN message are used for deleting the BFD session;

an activation module, configured to activate a timer corresponding to the type, when the packet is the ADMINDOWN packet; the activation module is further configured to activate a first timer corresponding to the ADMINDOWN packet, where a timing time of the first timer is less than a timing time of a second timer corresponding to a packet other than the ADMINDOWN packet;

and the sending module is used for sending the BFD message corresponding to the timer to a main control in the distributed system when the timer is overtime.

5. The apparatus according to claim 4, wherein before the line card sends a BFD packet corresponding to the timer to a master in a distributed system, the apparatus further comprises:

and the shielding module is used for shielding the second timer.

6. The apparatus of claim 5,

the sending module is further configured to send, by the line card, the ADMINDOWN packet to the master control in the distributed system when the first timer expires.