CN113542059A

CN113542059A - Segment routing multi-path BFD detection method, device and storage medium

Info

Publication number: CN113542059A
Application number: CN202110724195.4A
Authority: CN
Inventors: 蒋文栋
Original assignee: New H3C Big Data Technologies Co Ltd
Current assignee: New H3C Big Data Technologies Co Ltd
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2021-10-22
Anticipated expiration: 2041-06-29
Also published as: CN113542059B

Abstract

The disclosure provides a segment routing multi-path BFD detection method, a device and a storage medium, which are used for solving the technical problems that BFD detection cannot cover all forwarding paths and accurately evaluates the on-off condition of the whole path. The technical scheme includes that the BFD messages are expanded to obtain MPBFD messages, fields formed by the number of equivalent paths and the serial numbers of path exit ports are added when the routing nodes of each path from a source node to a destination node forward the BFD messages to next hops of a plurality of equivalent paths, the destination node identified by a segment identification list in a segment routing flow engineering strategy returns all received BFD messages to the source node, and the source node calculates the total path passing rate based on the returned BFD messages, so that the total on-off condition of the equivalent paths between the source node and the destination node can be accurately determined.

Description

Segment routing multi-path BFD detection method, device and storage medium

Technical Field

The present disclosure relates to the field of communications technologies, and in particular, to a method and an apparatus for detecting a segment routing multipath BFD, and a storage medium.

Background

The redundant backup link IS commonly used for protecting the link smoothness of key application, when a network fails, equipment IS required to be capable of quickly detecting the failure and switching flow to the backup link to accelerate the network convergence speed, the traditional protocols such as OSPF and IS-IS have a Fast Hello function to accelerate the detection speed, but the detection time can only reach the precision of 1 second, and BFD can enable the detection time to reach the millisecond level, so that the packet loss of user service flow IS reduced to the maximum extent.

The Segment Routing Engineering Policy (SRv 6-TE Policy) of IPv6 version is based on the Segment Routing Traffic Engineering Policy of IPv6 protocol version, and provides a flexible forwarding path selection method, which can meet different forwarding requirements of users. When a plurality of paths exist between a source node and a destination node of the Segment Routing network, SRv6-TE Policy is reasonably utilized to select a forwarding path, which not only facilitates the management and planning of the network by an administrator, but also effectively reduces the forwarding pressure of network equipment.

An SRv6-TE Policy consists of multiple Candidate Paths (Candidate Paths) with different priorities, each Candidate path including one or more forwarding Paths identified by a Segment Identification List (Segment Identification List, Segment-List or SID List). When the traffic is forwarded through SRv6-TE Policy, the device selects an optimal path from the candidate paths according to the priorities of the candidate paths. Different SRv6-TE policies cannot share the same candidate path.

The SID list contains message forwarding path information, and consists of the SID (IPv6 address) of each node on the forwarding path. The candidate path consists of one list of SIDs or a plurality of lists of weighted SIDs. SRv6-TE Policy selects a candidate path, and then performs load sharing among the SID lists of the candidate path according to the weight of the SID lists.

Bidirectional Forwarding Detection (BFD) is used in a Software Defined Network (SDN) to cooperate with SRv6-TE Policy or SR-TE Policy to realize the function of quickly switching flow to an available path or an escape default path when a certain path Down is detected at an equipment side, so as to achieve the purpose of reducing the packet loss of user service flow to the maximum extent.

SRV6 Policy may bind multiple candidate paths, and each candidate path may bind multiple SID lists, i.e., Segment-lists. The device creates a probing session for each SID list, and each probing session is directly forwarded according to the label stack of the corresponding SID list. In the candidate paths, if one SID list detects a path failure (Down), the device sets the SID list as Down, and the traffic is load-shared in the remaining normal (UP) SID lists, if the detection sessions of all SID lists in the candidate paths are Down, the entire candidate path Down walks other UP candidate paths, and if all the candidate paths are Down, the SRV6 Policy Down walks, and the traffic is forwarded by routing.

In actual engineering, in order to save the depth of the label stack and the deployment number of the SID lists, in some scenarios, an accurate path (path configuration is hop-by-hop end.x SID) is not set in the SID list, but an equivalent End SID path (an intermediate path is taken for route load sharing, and the path is required to pass through a certain node).

End SID: for identifying a certain destination address prefix in the network.

end.X SID: for identifying a link in the network.

If the device performs stream-by-stream forwarding, when Segment-list (i.e. SID list) is forwarded according to an equivalent route, the BFD packet is only detected along one path, and the traffic flow is random, and there is a possibility of traffic forwarding in each path, which results in incomplete BFD detection, inability to cover all forwarding paths and accurately evaluate the on-off condition of the entire path, and thus, inability to accurately link the on-off behavior of the SID list.

If the device forwards the packets one by one, when the SID list is forwarded according to the equivalent route, the BFD packet detection may have a detection result that is on and off at the same time, so that the service flow forwarding is continuously switched between the attachment layer overlay and the base layer underlay, and the actual service packet loss of the user is also unpredictable.

Disclosure of Invention

In view of this, the present disclosure provides a segment routing multi-path BFD detection method, apparatus and storage medium, for solving the technical problem that BFD detection cannot cover all forwarding paths and accurately evaluate the on-off condition of the entire path.

Fig. 1 is a multi-path BFD detection method for a segment route, which is provided in an embodiment of the present disclosure and is applied to a source node initiating multi-path bidirectional forwarding detection (MPBFD) in a network using a segment route traffic engineering policy, where the method includes:

step 101, generating a Bidirectional Forwarding Detection (BFD) control message, and copying the BFD control message according to the number of next hops of an equivalent path;

102, expanding BFD control messages according to the number of next hops of the equivalent path of the current node and the exit number of the next hops of the equivalent path to generate MPBFD control messages, and sending the MPBFD control messages to the next hops of the equivalent path through each equivalent path one by one;

the MPBFD control message carries an equivalent Path field, wherein the equivalent Path field comprises an equivalent Path Number Equal Path Number field, a Path exit Number Path ID field and a sender Address field;

103, after receiving the MPBFD control message returned by the destination node, calculating a passing rate weight proportion value of each equivalent path;

the passing rate weight proportion value is used for measuring the percentage of the MPBFD message number forwarded on each equivalent path in the total MPBFD message number;

step 104, calculating the total path passing rate of all the returned MPBFD control messages;

and 105, judging whether the sum path passing rate is smaller than a preset linkage detection threshold, if so, setting a path fault Down identified by a Segment identification list Segment-list in the Segment routing traffic engineering strategy, and otherwise, setting the path fault Down as a normal Up.

Further, the MPBFD control packet returned by the destination node carries one or more sets of equivalent path fields appended to one or more routing nodes on the path that the packet traverses;

the method for calculating the passing rate weight proportion value of each equivalent path comprises the following steps: 1 is divided by the product of all non-0 Equal Path Number field values in the message;

and the total path passing rate is equal to the sum of the passing rate weight proportion values of each equivalent path corresponding to all returned MPBFD control messages detected this time.

Further, the method further comprises:

determining the sending period of the MPBFD detection message as follows according to the number of the received returned MPBFD control messages: and multiplying the quantity of the returned MPBFD control messages on the basis of the packet sending interval negotiated by the BFD standard protocol.

Further, the method further comprises:

sending the MPBFD detection message according to the determined sending period of the MPBFD detection message;

the MPBFD detection message multiplexes a BFD detection message format, and the extension mode of the BFD detection message is the same as the extension mode of the BFD control message;

the method for calculating the passing rate weight proportion value and the total path passing rate of each equivalent path based on the MPBFD detection message is the same as the calculation mode based on the BFD control message.

Further, the MPBFD control message multiplexes the format of the BFD control message, expands the Authentication Type Auth Type field, Auth Len field and Authentication Data field to obtain an extended Type field, an extended Type Len field and an extended Type Data field, respectively, and carries the equivalent path field in the extended Type Data field.

Fig. 2 is a schematic structural diagram of a segment routing multi-path BFD detection apparatus according to an embodiment of the present disclosure, and each functional module in the apparatus 200 may be implemented by software, hardware, or a combination of software and hardware. When a plurality of hardware devices implement the technical solution of the present disclosure together, since the purpose of mutual cooperation among the hardware devices is to achieve the purpose of the present invention together, and the action and the processing result of one party determine the execution timing of the action of the other party and the result that can be obtained, it can be considered that the execution main bodies have mutual cooperation relationship, and the execution main bodies have mutual command and control relationship. The device 200 is applied to a source node initiating multi-path bidirectional forwarding detection (MPBFD) in a network adopting a segment routing traffic engineering strategy, and the device 200 comprises:

a message generating module 201, configured to generate a BFD control message, and copy the BFD control message according to the number of next hops of the equal-cost path;

the multi-path detection module 202 is configured to generate an MPBFD control packet according to the number of next hops of the equal-cost path of the current node and the extended BFD control packet of the next hop exit number of the equal-cost path, and send the MPBFD control packet to the next hop of the equal-cost path through each equal-cost path one by one; the MPBFD control message carries an equivalent Path field, wherein the equivalent Path field comprises an equivalent Path Number Equal Path Number field, a Path exit Number Path ID field and a sender Address field;

the passing rate calculation module 203 is configured to calculate a passing rate weight ratio value of each equal path after receiving the MPBFD control packet returned by the destination node; calculating the total path passing rate of all the received returned MPBFD control messages; the passing rate weight proportion value is used for identifying the percentage of the total path number of the paths which are passed by the MPBFD control message reaching the destination node;

and the detection result processing module 204 is configured to determine whether the sum path passing rate is smaller than a preset linkage detection threshold, if so, set a path fault Down identified by a Segment identification list Segment-list in the Segment routing traffic engineering policy, and otherwise, set the path fault Down as a normal Up.

the method for calculating the passing rate weight proportion value of each equivalent path by the passing rate calculation module 203 is as follows: 1 is divided by the product of all non-0 Equal Path Number field values in the message;

the method for calculating the sum path passing rate by the passing rate calculation module 203 is as follows: the total path passing rate is equal to the sum of the passing rate weight proportion values of each equivalent path corresponding to all returned MPBFD control messages detected this time.

Further, the apparatus 200 further comprises:

and the detection message period calculation module is used for determining the sending period of the MPBFD detection message according to the number of the received returned MPBFD control messages, wherein the sending period of the MPBFD detection message is equal to the number of the returned MPBFD control messages multiplied by the sending interval negotiated by the BFD standard protocol.

Further, the message generating module 201 is further configured to generate a BFD detection message, and copy the BFD detection message according to the number of next hops of the equivalent path;

the multi-path detection module 202 is further configured to send an MPBFD detection packet according to the determined sending period of the MPBFD detection packet;

the passing rate calculation module 203 is further configured to calculate a passing rate weight ratio value and a total path passing rate of each equivalent path based on the MPBFD detection packet in the same manner as the BFD control packet.

The technical scheme includes that BFD messages (including BFD control messages and BFD detection messages) are expanded to obtain MPBFD messages (including MPBFD control messages and MPBFD detection messages), fields formed by the number of equivalent paths and the numbers of path exit ports are added when routing nodes of each path from a source node to a destination node forward the BFD messages to next hops of a plurality of equivalent paths, all received BFD messages are returned to the source node by the destination node identified by a segment identification list in a segment routing flow engineering strategy, and the source node calculates the total path passing rate based on the returned BFD messages, so that the total on-off condition of the equivalent paths between the source node and the destination node can be accurately determined.

Drawings

In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments of the present disclosure or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present disclosure, and other drawings can be obtained by those skilled in the art according to the drawings of the embodiments of the present disclosure.

Fig. 1 is a schematic flow chart illustrating steps of a segment routing multi-path BFD detection method provided by the present disclosure;

fig. 2 is a schematic structural diagram of a segment routing multi-path BFD detection apparatus provided in the present disclosure;

fig. 3A is a schematic diagram of a message format of a BFD control message described in RFC;

fig. 3B is a schematic diagram of a format of an optional authentication field of a BFD control packet described in RFC;

fig. 4 is a schematic structural diagram of an extension field in an MPBFD control message according to an embodiment of the present disclosure;

figure 5 is a schematic SDN network topology of SRv6-TE Policy provided by an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of an electronic device capable of implementing a function of a segment routing multi-path BFD detection method according to an embodiment of the present disclosure.

Detailed Description

The terminology used in the embodiments of the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments of the present disclosure. As used in the embodiments of the present disclosure, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term "and/or" as used in this disclosure is meant to encompass any and all possible combinations of one or more of the associated listed items.

It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information in the embodiments of the present disclosure, such information should not be limited by these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of embodiments of the present disclosure. Depending on the context, moreover, the word "if" as used may be interpreted as "at … …" or "when … …" or "in response to a determination".

The invention aims to provide a Segment routing multi-path BFD detection method, which has the basic idea that BFD messages are expanded in an SDN network adopting an IPv4 or IPv6 Segment routing flow engineering strategy (SR-TE Policy or SRv6-TE Policy), when Segment-list of detection messages is forwarded according to an equivalent route, BFD detection covers all equivalent forwarding paths, all equivalent paths are traversed, and a head node can calculate the on-off percentage of the whole path according to the returned detection messages, so that the on-off condition of the whole path can be accurately evaluated, and the on-off behavior of the Segment-list can be accurately linked.

The technical scheme of the present disclosure extends the format of a BFD control packet of a BFD protocol, and the present disclosure names the extended BFD protocol as a multi-Path Bidirectional Forwarding Detection (MPBFD) protocol.

The BFD session operating mode is divided into a BFD control message mode and a BFD detection message (Echo message) mode, in which the BFD control message is encapsulated in a UDP message for transmission, the UDP destination port number for single-hop detection is 3784, and the UDP destination port number for multi-hop detection is 4784. The BFD Echo message is similar in format to the BFD control message (except that fields desiedmintxinterval and RequiredMinRXInterval are null) with a UDP destination port number of 3785.

Fig. 3A is a schematic diagram of a message format of a BFD control message described in RFC, where the BFD control message includes a mandatory part and an optional authentication part. Fig. 3B is a schematic diagram of a format of an optional authentication field of a BFD control packet described in RFC. The meanings of the fields of the BFD control message are shown in Table 1.

TABLE 1 BFD control message field meanings

The MPBFD control message provided by the disclosure multiplexes most fields in the BFD control message, and simultaneously expands the format of the BFD control message. According to the method, three fields of Auth Type, Auth Len and Authentication Data in the original BFD message format are collectively called Authentication fields. The embodiment of the present disclosure provides an extended field format for achieving the purpose of the present disclosure based on the format of an authentication field, where the extended field includes three fields of an extended Type, an extended Type Len, and an extended Type Data, and the specific meaning is described as follows:

1) the format of an authentication Type Auth Type field in the multiplexing authentication field correspondingly provides an extended Type field, and the extension mode of the field is as follows:

multiplexing the 0 th to 127 th bit positions of the original Auth Type field by the 0 th to 127 th bit positions of the extended Type field;

the 128 th bit of the extended Type field is used for the device to quickly determine whether the field is an extended Type field, for example, setting 1 indicates the field as an extended Type field, and setting 0 indicates the field as an Auth Type.

The 129 th bit of the extended Type field is used for identifying whether the message is an MPBFD message, and the MPBFD message is the upper concept of an MPBFD control message and an MPBFD detection message and comprises an MPBFD control message and an MPBFD detection message.

The format of the extended Type field in this embodiment is only an extended form, and for example, other one or more bits in the Auth Type or one or more bits in other fields may also be selected to indicate whether the current BFD control packet is an MPBFD control packet, which is not described in detail in this disclosure.

2) And multiplexing an Auth Len field format in the authentication field, and correspondingly providing an extended Type length extended Type Len field for indicating the total length of the data of the extended Type.

3) And multiplexing the format of the Authentication Data field in the Authentication field, correspondingly providing an extended Type Data field for bearing an equivalent path field corresponding to the equivalent path.

When the extended Type field identifies that the current BFD message is an MPBFD message, the extended Type Data field of the MPBFD message may contain multiple Equal-cost Path fields, where the Equal-cost Path fields include Equal-cost Path Number field, Path exit Number Path ID field, and sender Address field, and may further include 3 sender Address Type fields in order to be compatible with different Address types. The entire Extend Type Data field in each MPBFD message returned to the source uniquely identifies an equivalent path from the source to the destination. When the Equal Path Number and the Path ID field values in the Equal Path field are both 0, the current MPDFD message is a return message.

The format of the extended Type Data field in this embodiment is only an extended form, for example, other information fields may be added in addition to the Equal Path Number, Path ID, and Source Address fields, and this disclosure is not repeated.

Fig. 4 is a schematic structural diagram of an extension field in the MPBFD control message provided in this embodiment.

On the basis of expanding a BFD protocol, the embodiment of the disclosure improves a path detection mode of a BFD message, and provides a new multi-path BFD detection method, the method is applied to networking adopting a segment routing flow engineering strategy, BFD detection is simultaneously carried out on all equivalent paths based on SR-TE Policy/SRv6-TE Policy, a total passing rate is calculated according to a feedback BFD response message, when the total passing rate reaches a preset threshold value, a normal Up of a link between a source node and a destination node is judged, otherwise, a fault Down is judged.

The following describes the steps and flows of the segment routing multi-path BFD detection method provided by the present disclosure in detail with reference to a specific example:

b101, setting a current detection mode as a multi-path bidirectional forwarding detection (MPBFD) mode, and setting a linkage detection threshold;

in the embodiment of the present disclosure, on an Edge router (Provider Edge, PE), that is, a source node of a service Provider backbone network initiating BFD detection, a BFD detection mode or an MPBFD detection mode may be selected and used through a configuration file, and in the MPBFD detection mode, a linked detection threshold of MPBFD needs to be set at the same time. And linking the BFD Down when the sum passing rate of the equivalent paths is less than the linkage detection threshold, and linking the BFD Up when the sum passing rate of the equivalent paths is greater than or equal to the linkage detection threshold. The numerical value of the linkage detection threshold is an integer of 1-100%, and a user is allowed to set the linkage detection threshold according to actual business requirements.

B102, the source node generates a BFD control message, and copies the BFD control message according to the number of next hops of the equivalent path;

the BFD control message refers to an original standard BFD control message generated based on a BFD protocol and is different from an MPBFD control message. For the case of N candidate paths, N-1 BFD control packets need to be replicated to satisfy the condition that one MPBFD control packet can be sent over each equivalent path.

Step B103, expanding the BFD control message according to the number of the next hops of the equivalent path of the current node and the exit number of the next hops of the equivalent path to obtain an MPBFD control message, and sending the MPBFD control message to the next hops of the equivalent path through each equivalent path one by one;

each Equal Path field (located in the extended Type Data field in the extended field) in the MPBFD control message carries the Equal Path Number field, the Path exit Number Path ID field, and the sender Address Source Address field of the current node. The Equal Path Number is the Number of the next hop of the Equal Path of the current node, the Path ID is the exit Number of the Equal Path corresponding to the Equal Path, and the Source Address field of the sender is the Address of the current node (for the next hop node, the Source Address of the received message).

When the MPBFD control message reaches a main router (P equipment for short) in a service provider core network, the processing steps of the P equipment are as follows:

and B104, when the P equipment receives the MPBFD control message, judging whether the message is a return message according to the field values of the last group of Equal Path Number and Path ID in the extended field, if so, executing the step B105, otherwise, executing the step B106.

In an embodiment of the present disclosure, when receiving an MPBFD control packet forwarded from different Equal-cost paths, a destination node adds an Equal-cost Path field with a value of 0 to an extension field of each control packet, that is, Equal Path Number, Path ID, and Source Address field values in the added Equal-cost Path field are all 0, and therefore, when a P device receives an MPBFD control packet in a backhaul, it determines whether the current MPBFD control packet is a return packet by determining whether the last Equal-cost Path field value is 0.

Other embodiments of the present disclosure may also use other manners or other identifiers to identify whether an MPBFD packet is a return packet, and the present disclosure is not limited specifically, for example, a field specially used for identifying a backhaul is added to an extension field or an equivalent path field value is set to other special values, and the like, and details are not described in the present disclosure.

And step B105. the P equipment directly forwards the message to a message destination node according to the routing strategy.

When receiving the returned MPBFD control message, the P node analyzes the Source Address field in the MPBFD control message from back to front. And by searching the local routing table, if the Source Address is matched, emptying the Source Address, and sending out the message through an output interface corresponding to the Source Address.

And B106. the P device copies the received MPBFD control message according to the Number of the equivalent next hops of the current node, adds an equivalent Path field corresponding to the current node to the MPBFD control message corresponding to each equivalent Path, wherein the equivalent Path field corresponding to the current node comprises an equivalent Path Number Equal Path Number field of the current node, an equivalent Path exit Number Path ID field and a sender Address field, and sends the corresponding MPBFD control message to the next hop through each equivalent Path.

When the MPBFD control message reaches the target node of BFD detection, the step of the target node processing the MPBFD control message is as follows:

and B107, after the destination node receives the MPBFD control messages, adding an equivalent path field with a value of 0 to the tail of the extension field of each received MPBFD control message to indicate that the messages reach the destination, and then returning the MPBFD control messages to the source node.

In order to decide which node should return the currently processed MPBFD control message to be returned to, the destination node analyzes the Source Address field in the MPBFD control message from back to front. And by searching the local routing table, if the Source Address is matched, emptying the Source Address, and sending out the current MPBFD control message through an output interface corresponding to the Source Address.

The processing steps after the source node receives the MPBFD control message returned by the destination node are as follows:

and B109, after receiving the MPBFD control message returned by the destination node, calculating the passing rate weight proportion value of each equivalent path according to the returned MPBFD control message. The passing rate weight proportion value of each equivalent path is used for measuring the percentage of the MPBFD message number forwarded on each equivalent path to the total MPBFD message number (in a detection period). The specific passing rate weight ratio for returning a plurality of MPBFD messages and each equivalent path is determined by the number of times of shunting, the number of shunting at each time and the shunting sequence, and the calculation mode is as follows:

the passing rate weight ratio value of each Equal cost Path is 1 divided by the product of all non-0 Equal Path Number field values in the extended Type Data field.

And the source node for MPBFD detection receives the MPBFD control message returned by the destination node in a preset period.

Step B110, calculating the total path passing rate of all the returned MPBFD control messages, wherein the calculation mode is as follows:

and the total path passing rate is the sum of the passing rate weight proportion values of each equivalent path corresponding to all returned MPBFD control messages detected this time.

B111, judging whether the total path passing rate is smaller than a preset linkage detection threshold value or not;

and step B112, when the total path passing rate of the MPBFD negotiation is judged to be less than the preset linkage detection threshold, the BFD negotiation of the path set by the Segment list, namely the path set by the Segment list, in the Segment list set on the basis of the SR-TE Policy/SRv6-TE Policy is failed, and the path state is reported to be a fault state.

And B113, when the total path passing rate of the MPBFD negotiation is judged to be greater than or equal to a preset linkage detection threshold, successfully negotiating the BFD of the path set by the Segment list, namely the path set UP in the Segment list set on the basis of the SR-TE Policy/SRv6-TE Policy, and reporting that the path state is a normal state.

And B114, determining the sending period of the MPBFD detection message according to the quantity of the received returned MPBFD control message as follows: and multiplying the quantity of the returned MPBFD control messages on the basis of the packet sending interval negotiated by the BFD standard protocol.

And B115, sending the MPBFD detection message according to the determined sending period of the MPBFD detection message.

The forwarding flow of the MPBFD detection packet and the processing flow of the source node based on the MPBFD detection packet are explained as follows:

1) the MPBFD detection message forwarding flow is the same as the MPBFD control message forwarding flow, and the MPBFD detection message and the MPBFD control message use the same extension field.

2) After receiving the returned MPBFD detection message, the source node equipment also updates the message sending period of the MPBFD detection message at the side in real time as in the MPBFD session negotiation stage.

3) And the source node equipment continuously calculates the total path passing rate of the specified path of the Segment list, if the total path passing rate is less than the configured linkage detection threshold, the BFD Session reports Down, and the corresponding Segment list is put Down. And if the sum path passing rate is greater than or equal to the configured linkage detection threshold, the BFD Session reports UP, and the corresponding Segment list is UP.

Fig. 5 is an SDN network topology schematic diagram of SRv6-TE Policy provided in an embodiment of the present disclosure, where PE1 is a source node of BFD detection, PE2 is a destination node of BFD detection, multiple equivalent paths are provided between PE1 and PE2, an MPBFD packet may be forwarded according to Segment-list by an equivalent route based on SRv6-TE Policy, and an MPBFD control packet is taken as an example to describe an MPBFD detection process provided in the present disclosure:

1) generating an original standard BFD control message on PE 1;

PE1 finds that there are 4 equivalent next hops for PE 2: PE1- > P3, PE1- > P7, PE1- > P8 and PE1- > P9. And subtracting one copy BFD control message from the next hop number of the equivalent path on the PE1 node, namely copying 3 messages, and 4 messages in total.

2) PE1 expands the BFD control message into an MPBFD control message;

PE1 expands the 4 BFD control packets into 4 MPBFD control packets corresponding to each equal cost path, respectively:

PK 1: [4,1 ]; the current forwarding path: PE1- > P3, where 4 in [4,1] is the Equal Path Number field, and 1 is the Path exit Number Path ID corresponding to the current Equal Path PK 1. The meaning of the extended Type Data field of other paths is the same, and will not be described in detail below.

PK 2: [4,2 ]; the current forwarding path: PE1- > P7.

PK 3: [4,3 ]; the current forwarding path: PE1- > P8.

PK 4: [4,4 ]; the current forwarding path: PE1- > P9.

3) And (3) processing and sending a message on the P node:

after receiving the MPBFD control message, the P3 node copies the MPBFD control message according to the Number of the next hops of the equivalent Path, and adds the values of the Equal Path Number field and the Path ID field corresponding to the equivalent Path in the extended Type Data field for each next hop.

The MPBFD control message received by the P3 node is:

PK 1: [4,1 ]; the current forwarding path: PE1- > P3.

The MPBFD control messages sent by the P3 node to the next hop of 3 equal-cost paths are respectively:

PK 1: [4,1] [3,1 ]; the current forwarding path: PE1- > P3- > P4.

PK 5: [4,1] [3,2 ]; the current forwarding path: PE1- > P3- > P6.

PK 6: [4,1] [3,3 ]; the current forwarding path: PE1- > P3- > P7.

Similarly, the MPBFD control message received by the P7 node is:

PK 2: [4,2 ]; the current forwarding path: PE1- > P7.

PK 6: [4,1] [3,3 ]; the current forwarding path: PE1- > P3- > P7.

When the P7 node sends an MPBFD control packet to the next hop of 2 equal-cost paths, the two MPBFD control packets from P3 and PE1 are copied separately, so the following 4 packets need to be sent:

PK 2: [4,2] [2,1 ]; the current forwarding path: PE1- > P7- > PE2 (1).

PK 7: [4,2] [2,2 ]; the current forwarding path: PE1- > P7- > PE2 (2).

PK 6: [4,1] [3,3] [2,1 ]; the current forwarding path: PE1- > P3- > P7- > PE2 (1).

PK 8: [4,1] [3,3] [2,2 ]; the current forwarding path: PE1- > P3- > P7- > PE2 (2).

Similarly, the processing at the P8 node is as follows:

the received MPBFD control message is as follows:

PK 3: [4,3 ]; the current forwarding path: PE1- > P8.

The MPBFD control message sent to the next hop of the equivalent path is as follows:

PK 3: [4,3] [1,1 ]; the current forwarding path: PE1- > P8- > PE 2.

Similarly, the processing at the P9 node is as follows:

the received MPBFD control message is as follows:

PK 4: [4,4 ]; the current forwarding path: PE1- > P9.

PK 4: [4,4] [1,1 ]; the current forwarding path: PE1- > P9- > PE 2.

Similarly, the processing at the P4 node is as follows:

the received MPBFD control message is as follows:

PK 1: [4,1] [3,1 ]; the current forwarding path: PE1- > P3- > P4.

PK 1: [4,1] [3,1] [1,1 ]; the current forwarding path: PE1- > P3- > P4- > P5.

Similarly, the processing at the P6 node is as follows:

the received MPBFD control message is as follows:

PK 5: [4,1] [3,2 ]; the current forwarding path: PE1- > P3- > P6.

The MPBFD control message sent by the next hop of the lower equivalent path is as follows:

PK 5: [4,1] [3,2] [1,1 ]; the current forwarding path: PE1- > P3- > P6- > P5.

Similarly, the processing at the P5 node is as follows:

the received MPBFD control message is as follows:

PK 1: [4,1] [3,1] [1,1 ]; the current forwarding path: PE1- > P3- > P4- > P5.

PK 5: [4,1] [3,2] [1,1 ]; the current forwarding path: PE1- > P3- > P6- > P5.

PK 1: [4,1] [3,1] [1,1] [1,1 ]; the current forwarding path: PE1- > P3- > P4- > P5- > PE 2.

PK 5: [4,1] [3,2] [1,1] [1,1 ]; the current forwarding path: PE1- > P3- > P6- > P5- > PE 2.

4) The processing at destination node PE2 is as follows:

the received MPBFD control message is as follows:

PK 2: [4,2] [2,1 ]; the current forwarding path: PE1- > P7- > PE2 (1).

PK 3: [4,3] [1,1 ]; the current forwarding path: PE1- > P8- > PE 2.

PK 4: [4,4] [1,1 ]; the current forwarding path: PE1- > P9- > PE 2.

PK 7: [4,2] [2,2 ]; the current forwarding path: PE1- > P7- > PE2 (2).

After the PE2 receives the MPBFD control message, because the MPBFD control message is a destination node, the control message is not copied any more, the PE2 adds a group of Equal Path Number fields and Path ID fields with all field values of 0 to the extended Type Data field of each received MPBFD control message, so as to identify the message as a return message, and then the PE2 parses the Source Address field in the MPBFD control message from back to front. And by searching the local routing table, if the Source Address is matched, emptying the Source Address, and sending a message through an output interface corresponding to the Source Address.

5) Processing return messages on the P node:

and resolving a Source Address field in the MPBFD control message from back to front. And by searching the local routing table, if the Source Address is matched, emptying the Source Address, and sending a message through an output interface corresponding to the Source Address.

6) The processing steps of the source node PE1 for receiving the returned MPBFD control packet are as follows:

A) firstly, respectively calculating the passing rate weight proportion value of the equivalent path corresponding to each returned message:

path PK 1: [4,1][3,1][1,1][1,1]The corresponding value is a proportional value of W_pk1＝1/(4*3*1*1)＝1/12；

Path PK 2: [4,2][2,1]The corresponding value is a proportional value of W_pk2＝1/(4*2)＝1/8；

Path PK 3: [4,3][1,1]The corresponding value is a proportional value of W_pk3＝1/(4*1)＝1/4；

Path PK 4: [4,4][1,1]The corresponding value is a proportional value of W_pk4＝1/(4*1)＝1/4；

Path PK 5: [4,1][3,2][1,1][1,1]The corresponding value is a proportional value of W_pk5＝1/(4*3*1*1)＝1/12；

Path PK 6: [4,1][3,3][2,1]The corresponding value is a proportional value of W_pk6＝1/(4*3*2)＝1/24；

Path PK 7: [4,2][2,2]The corresponding value is a proportional value of W_pk7＝1/(4*2)＝1/8；

Path PK 8: [4,1][3,3][2,2]The corresponding value is a proportional value of W_pk8＝1/(4*3*2)＝1/24。

B) Calculating the total path passing rate of all paths in the following way:

total path passing rate W_pk1+W_pk2+W_pk3+W_pk4+W_pk5+W_pk6+W_pk7+W_pk8＝1/12+1/8+1/4+1/4+1/12+1/24+1/8+1/24＝(2+3+6+6+2+1+3+1)/24＝100％。

It can be seen that, in this embodiment, under the condition that all paths are unblocked, the total path passing rate is 100%, and if a certain path fails, the passing rate weight proportion value corresponding to the path is correspondingly subtracted, so as to obtain the on-off percentage of the whole path.

C) In this embodiment, the set linkage detection threshold is 60%, and if the total path passing rate is smaller than this value, the negotiation process of the BFD control packet fails, and the corresponding Segment list is set Down.

In this embodiment, if two paths PK3 and PK4 have failed and the other paths are normal, and return messages of the two paths PK3 and PK4 are not received, then W calculates the total path throughput_pk3+W_pk4The final calculated total passing rate is 50% and is smaller than the set linkage detection threshold, so that the failure of BFD detection at the time is judged, and the path corresponding to the Segment list is reported to Down on the source node.

If the sum path passing rate is greater than or equal to the configured linkage detection threshold, it can be determined that the negotiation of the MPBFD control message is successful, and then the source node can determine the sending period of the MPBFD detection message according to the number of the received returned MPBFD control messages:

and multiplying the quantity of the returned MPBFD control messages on the basis of the packet sending interval negotiated by the BFD standard protocol.

D) And sending the MPBFD detection message according to the determined sending period of the MPBFD detection message.

Fig. 6 is a schematic structural diagram of an electronic device capable of implementing a function of a segment routing multi-path BFD detection method according to an embodiment of the present disclosure, where the device 600 includes: a processor 610 such as a Central Processing Unit (CPU), a communication bus 620, a communication interface 640, and a storage medium 630. Wherein the processor 610 and the storage medium 630 may communicate with each other through a communication bus 620. The storage medium 630 has stored therein a computer program that, when executed by the processor 610, performs the functions of the steps of the methods provided by the present disclosure.

The storage medium may include a Random Access Memory (RAM) or a Non-Volatile Memory (NVM), such as at least one disk Memory. In addition, the storage medium may be at least one memory device located remotely from the processor. The Processor may be a general-purpose Processor including a Central Processing Unit (CPU), a Network Processor (NP), etc.; but also Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components.

It should be recognized that embodiments of the present disclosure can be realized and implemented by computer hardware, a combination of hardware and software, or by computer instructions stored in a non-transitory memory. The method may be implemented in a computer program using standard programming techniques, including a non-transitory storage medium configured with the computer program, where the storage medium so configured causes a computer to operate in a specific and predefined manner. Each program may be implemented in a high level procedural or object oriented programming language to communicate with a computer system. However, the program(s) can be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language. Furthermore, the program can be run on a programmed application specific integrated circuit for this purpose. Further, operations of processes described by the present disclosure may be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The processes described in this disclosure (or variations and/or combinations thereof) may be performed under the control of one or more computer systems configured with executable instructions and may be implemented as code (e.g., executable instructions, one or more computer programs, or one or more applications) executing collectively on one or more processors, by hardware, or combinations thereof. The computer program includes a plurality of instructions executable by one or more processors.

Further, the method may be implemented in any type of computing platform operatively connected to a suitable interface, including but not limited to a personal computer, mini computer, mainframe, workstation, networked or distributed computing environment, separate or integrated computer platform, or in communication with a charged particle tool or other imaging device, and the like. Aspects of the disclosure may be embodied in machine-readable code stored on a non-transitory storage medium or device, whether removable or integrated into a computing platform, such as a hard disk, optically read and/or write storage medium, RAM, ROM, or the like, such that it may be read by a programmable computer, which when read by the storage medium or device, is operative to configure and operate the computer to perform the procedures described herein. Further, the machine-readable code, or portions thereof, may be transmitted over a wired or wireless network. The invention described in this disclosure includes these and other different types of non-transitory computer-readable storage media when such media include instructions or programs that implement the steps described above in conjunction with a microprocessor or other data processor. The disclosure also includes the computer itself when programmed according to the methods and techniques described in this disclosure.

The above description is only an example of the present disclosure and is not intended to limit the present disclosure. Various modifications and variations of this disclosure will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A segment routing multi-path BFD detection method is applied to a source node initiating multi-path bidirectional forwarding detection (MPBFD) in a network adopting a segment routing flow engineering strategy, and comprises the following steps:

generating a Bidirectional Forwarding Detection (BFD) control message, and copying the BFD control message according to the number of next hops of the equivalent path;

expanding a BFD control message according to the number of next hops of the equivalent path of the current node and the exit number of the next hops of the equivalent path to generate an MPBFD control message, and sending the MPBFD control message to the next hops of the equivalent path through each equivalent path one by one; the MPBFD control message carries an equivalent Path field, wherein the equivalent Path field comprises an equivalent Path Number Equal Path Number field, a Path exit Number Path ID field and a sender Address field;

after receiving MPBFD control messages returned by the destination node, calculating a passing rate weight proportion value of each equivalent path, wherein the passing rate weight proportion value is used for measuring the percentage of the number of MPBFD messages forwarded on each equivalent path to the total number of MPBFD messages;

calculating the total path passing rate of all the received returned MPBFD control messages;

and judging whether the sum path passing rate is smaller than a preset linkage detection threshold, if so, setting the path fault Down identified by a Segment identification list Segment-list in the Segment routing traffic engineering strategy, and otherwise, setting the path fault Down as a normal Up.

2. The method of claim 1,

the MPBFD control message returned by the destination node carries one or more groups of equivalent path fields attached to one or more routing nodes on the path which the message passes through;

3. The method of claim 1, further comprising:

4. The method of claim 3, further comprising:

5. The method of claim 1,

the MPBFD control message multiplexes the format of the BFD control message, the Authentication Type Auth Type field, Auth Len field and Authentication Data field are expanded to respectively obtain an extended Type field, an extended Type Len field and an extended Type Data field, and the extended Type Data field carries the equivalent path field.

6. A segment routing multi-path BFD detection device is applied to a source node initiating multi-path bidirectional forwarding detection (MPBFD) in a network adopting a segment routing flow engineering strategy, and the device comprises:

the message generating module is used for generating a BFD control message and copying the BFD control message according to the number of next hops of the equivalent path;

the multi-path detection module is used for expanding the BFD control message according to the number of the next hops of the equivalent path of the current node and the exit number of the next hops of the equivalent path to generate an MPBFD control message, and sending the MPBFD control message to the next hops of the equivalent path through each equivalent path one by one; the MPBFD control message carries an equivalent Path field, wherein the equivalent Path field comprises an equivalent Path Number Equal Path Number field, a Path exit Number Path ID field and a sender Address field;

the passing rate calculation module is used for calculating a passing rate weight proportion value of each equivalent path after receiving the MPBFD control message returned by the destination node; calculating the total path passing rate of all the received returned MPBFD control messages; the passing rate weight proportion value is used for identifying the percentage of the total path number of the paths which are passed by the MPBFD control message reaching the destination node;

and the detection result processing module is used for judging whether the total path passing rate is smaller than a preset linkage detection threshold, if so, setting the path fault Down identified by the Segment identification list Segment-list in the Segment routing traffic engineering strategy, and otherwise, setting the path fault Down as the normal Up.

7. The apparatus of claim 6,

the method for calculating the passing rate weight proportion value of each equivalent path by the passing rate calculation module comprises the following steps: 1 is divided by the product of all non-0 Equal Path Number field values in the message;

the method for calculating the sum path passing rate by the passing rate calculation module comprises the following steps: the total path passing rate is equal to the sum of the passing rate weight proportion values of each equivalent path corresponding to all returned MPBFD control messages detected this time.

8. The apparatus of claim 6, further comprising:

9. The apparatus of claim 8,

the message generation module is also used for generating BFD detection messages and copying the BFD detection messages according to the number of the next hops of the equivalent path;

the multi-path detection module is also used for sending the MPBFD detection message according to the determined sending period of the MPBFD detection message;

and the passing rate calculation module is also used for calculating the passing rate weight proportion value and the total path passing rate of each equivalent path based on the MPBFD detection message in the same mode as the BFD control message.

10. A storage medium on which a computer program is stored which, when being executed by a processor, carries out the method steps of any one of claims 1 to 5.