CN114244468A

CN114244468A - Method, storage medium and equipment for rapidly positioning fault point of OTN link

Info

Publication number: CN114244468A
Application number: CN202111585458.4A
Authority: CN
Inventors: 赵从林
Original assignee: Anhui Wantong Post And Telecommunications Co ltd
Current assignee: Anhui Wantong Post And Telecommunications Co ltd
Priority date: 2021-12-23
Filing date: 2021-12-23
Publication date: 2022-03-25

Abstract

The invention discloses a method, a storage medium and equipment for rapidly positioning a fault point of an OTN link, which comprises the following steps of 1, transmitting a CCM message periodically from an MEP to an affiliated MA in a multicast mode; step 2, the MEP sends CCM messages, and the period of sending the CCM messages by the MEP is specified to be 7 types in a protocol; step 3, the MEP receives the CCM message, and the CFM judges the link fault in the MA and depends on the MEP to receive the CCM message; step 4, MIP sends and receives CCM message, MIP will not send CCM message voluntarily; after receiving the CCM message, the MIP directly multicasts and forwards the message if the MD Level is not equal to the MD Level to which the MIP belongs, and updates the MIP CCM Database if the MD Level is equal to the MD Level. The invention can solve the problem that a positioning means provided by the fault exists in the transmission process of the OTN link, can realize fault troubleshooting based on segmentation, periodically sends a detection message and efficiently feeds back a fault point.

Description

Method, storage medium and equipment for rapidly positioning fault point of OTN link

Technical Field

The invention relates to the technical field of network communication, in particular to a method, a storage medium and equipment for quickly positioning a fault point of an OTN link.

Background

The OTN is a next-generation backbone transport network based on a wavelength division multiplexing technology and organized in an optical layer. OTN passes through a new generation of "digital transport" and "optical transport" as specified by a series of ITU-T recommendations, g.872, g.709, g.798, and so on. The OTN solves the problems of weak scheduling capability, networking capability, protection capability and the like of the traditional WDM network wavelength-free/sub-wavelength service. At the edge layer of the OTN network, signals of different systems are encapsulated into a frame structure in a unified OTN system with rich overhead, and based on the frame structure, the unified operation, management and maintenance of the WDM whole network based on the OTN system are realized.

The OTN technology (OTH in the electrical domain and ROADM in the optical domain) solves the problems that the cross grain of SDH based on VC-12/VC4 is smaller, the scheduling is more complex and the requirement of large-grain service transmission is not met, and partially overcomes the defects that the fault location of a WDM system is difficult, the networking capability is weaker in a networking mode taking point-to-point connection as a main mode, and the provided network survivability means and capability are weaker.

Disclosure of Invention

The invention provides a method, a storage medium and equipment for rapidly positioning a fault point of an OTN link, which can at least solve one of the technical problems in the background art.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for rapidly positioning a fault point of an OTN link comprises the following steps executed by computer equipment,

step 1, CCM messages are periodically forwarded to the affiliated MA by MEPs in a multicast mode, other MEPs in the MA update their MEP databases after receiving the messages, the CCM messages cannot be responded, and MIPs in the MA do not process CCM and only take charge of transparent forwarding;

step 2, the MEP sends CCM messages, and the period of sending the CCM messages by the MEP is specified to be 7 in a protocol, namely 3.33ms, 10ms, 100ms, 1s, 10s, 1min and 10 min; the information is carried in a Flag field of a common CFM header, and 3 bits are used for representing the 7 sending periods; CCM sending periods of all MEPs in one MA are consistent, otherwise, configuration errors are considered to occur, and an alarm is needed;

step 3, the MEP receives the CCM message, and the CFM judges the link fault in the MA and depends on the MEP to receive the CCM message; if the CCM of a certain MEP in the MA is not received in a certain period, the MEP is considered to be in failure or a link in the MA is considered to be in failure;

step 4, MIP sends and receives CCM message, MIP will not send CCM message voluntarily; after receiving the CCM message, the MIP directly multicasts and forwards the message if the MD Level is not equal to the MD Level to which the MIP belongs, and updates the MIP CCM Database if the MD Level is equal to the MD Level.

Further, in step 3, the protocol defines 5 errors according to the CCM reception condition:

(1) if one MEP continuously does not receive 3 CCMs sent by some other MEP in the MA, indicating that the MEP or the network fails, the MEP internal timer is not updated within 3.5 times of the sending period, and then the failure is considered to occur;

(2) if one MEP receives CCM with MD Level lower than that of the MEP, configuration error is indicated, or link cross connection is possible;

(3) if one MEP receives the MD level which is carried by the CCM and is the same as the MD level of the MEP, but the MAID is not equal to the MAID of the MEP, the MEP considers that link crossing or configuration error occurs;

(4) if an MEP receives the same MD level and correct MAID but the MEP ID is wrong, the MEP considers that the configuration is wrong or the link is in cross connection, wherein the wrong condition is that the MEP ID in the non-configuration range is received or the received MEP ID is equal to the MEP ID of the MEP;

(5) if an MEP receives correct MD level, MA ID and MEP ID, but receives the condition that the sending period in CCM is not equal to the sending period of the MEP, configuration error may occur;

if all the information is correct, updating remote MEP CCM Database, wherein the information contained in the Database comprises the state of the remote MEP, the state holding time, the mac address of the remote MEP, RDI information and the like;

the RDI information comprises the first bit of Flag in the common CCM Header of the CCM message and is used for indicating that the MEP sending the CCM finds that one MEP in the MA has a fault.

In yet another aspect, the present invention also discloses a computer readable storage medium storing a computer program, which when executed by a processor causes the processor to perform the steps of the method as described above.

In yet another aspect, the present invention also discloses a computer device comprising a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to perform the steps of the above method.

According to the technical scheme, the method and the system for rapidly positioning the fault point on the OTN link can realize the periodic sending of the controllable protocol message to detect the fault point existing in the OTN link, and can realize the sectional inspection.

The invention can solve the problem that a positioning means provided by the fault exists in the transmission process of the OTN link, can realize fault troubleshooting based on segmentation, periodically sends a detection message and efficiently feeds back a fault point.

Drawings

FIG. 1 is a schematic flow chart illustrating the concept of OCFM in the present invention;

fig. 2 shows a message format of CCM in the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.

As shown in fig. 1, the method for quickly locating a failure point in an OTN link according to this embodiment is applied to a system device supporting an OTN function, which is abbreviated as ocfm (OTN Connectivity Fault management), and as shown in fig. 1 and fig. 2, includes the following steps:

the invention provides a method for quickly positioning a fault point based on an OTN link, which is used for quickly solving the problem that the existing OTN network equipment has the fault point.

The noun meaning of OCFM is explained as follows:

in an MD, there are Service Access Points (SAP) that need to be managed and monitored, called as "dosap" (domain Service Access Point "), and these nodes need to send, receive and process CFM PDUs, so as to implement management of a maintenance domain and location of a fault, etc., and these nodes are called as" MPs ". In the maintenance domain, according to different requirements, for example, nodes carry different services or belong to different users, the nodes are divided into different sets, and the set is the maintenance association MA. The MA uses MAID and MD Level as its definition, which is actually different service instances, and there may be multiple MAs in one MD, but one MA can only belong to one MD.

At the boundary of an MA, nodes in the MA which are responsible for sending and receiving CFMPDUs are called MEPs (Maintenance association End points), and MPs which are located in the MA and are only responsible for relaying and forwarding CCM messages in CFM (CCM MD Level is higher than or equal to own MD Level) are called MIPs (Maintenance domain Intermediate points)

In particular, the invention provides a method for realizing link fault point positioning by a control message,

the method is applied to system equipment supporting OTN function, and comprises the following steps:

step 1, a CCM Message (Continuity Check Message) is periodically forwarded to the affiliated MA by the MEP in a multicast mode, other MEPs in the MA update their MEP databases (MEP CCM databases) after receiving the CCM Message, and the MIP in the MA does not process CCM and is only responsible for transparent forwarding

And step 2, the MEP sends the CCM message, and the period of sending the CCM message by the MEP is specified to be 7 in the protocol, namely 3.33ms, 10ms, 100ms, 1s, 10s, 1min and 10 min. This information is carried in the Flag field of the common CFM header (1 oct) and 3 bits are used to indicate these 7 transmission periods. (0 is an illegal value, see IEEE 802.1ag Table 21-16 for details). CCM sending periods of all MEPs in one MA are consistent, otherwise, configuration errors are considered to occur, and an alarm is needed.

And 3, the MEP receives the CCM message, and the CFM judges the link fault in the MA depending on the reception of the CCM message by the MEP. If no CCM of a certain MEP in the MA is received within a certain period, the MEP is considered to be in failure or a link in the MA is considered to be in failure. The protocol specifies 5 errors based on CCM reception:

(1) if an MEP continuously does not receive 3 CCMs sent by some other MEP in the MA, the MEP or the network is failed. The MEP internal timer is considered to be failed if it is not updated within 3.5 times the transmission period.

if all the above information is correct, remote MEP CCM Database is updated, and the information contained in the Database includes the status of the remote MEP, the time for status maintenance, the mac address of the remote MEP, RDI information, and the like (see protocol 12.14.7.6.3 for details). The RDI information includes the first bit of Flag in common CCM Header of the CCM message, and is used to indicate that the MEP sending the CCM finds that one MEP in the MA has a fault. The processing of RDI is exemplified as follows: if A continuously loses 3 CCM messages from B, the RDI is set when the A multicasts the CCM of the A, the C receives the CCM of the A and finds that the RDI is set, the RDI in the item of the A is set in the database, and the RDI of the CCM of the C is also set, so that all MEPs can know that a fault occurs in the MA, but the method can not locate the fault.

And 4, the MIP sends and receives the CCM message, and the MIP cannot actively send the CCM message. After receiving the CCM message, the MIP directly multicasts and forwards the message if the MD Level is not equal to the MD Level to which the MIP belongs, and updates the MIP CCM Database if the MD Level is equal to the MD Level.

Each MEP receives the CCM sent by other MEPs, does not generate a response message, and only records the information of other MEPs in the CCM database of the MEP.

For example, there are n MEPs in an MA, each MEP sends CCMs to other n-1 MEPs to tell other MEPs its own related information, each MEP receives n-1 CCMs, and for an MEP, if the received information of all other MEPs meets the condition that MAID is the same, MD Level is the same, and MEPIDs are different, it is said that the link has no failure.

The following are several cases that indicate a link failure:

if one MEP cannot receive 3 consecutive CCMs sent from other MEPs in the MA, it indicates that there is an MEP therein or that the network is down. The 3 CCMs are generated because of a timer mechanism inside the MEP, when a valid CCM is received, the timer is reset, when a fault occurs, the operation of the timer is terminated, and the timer is automatically triggered to indicate the fault if 3 continuous CCMs cannot be received;

if one MEP receives the CCM of the error transmission interval, the CCM packet sending periods of two sides are inconsistent or errors are configured;

if an MEP receives a CCM with an incorrect MEPID or MAID, configuration errors or possible link cross-connection are indicated;

if one MEP receives CCM with MD Level lower than that of the MEP, configuration error is indicated, or link cross connection is possible;

if one MEP receives the CCM comprising the port status TLV or the interface status TLV, indicating that the connection port or the aggregation port has a fault;

loopback Message (Loopback Message LBM) and Loopback response (Loopback Reply LBR)

The LBM is used for fault confirmation and isolation, the connectivity between the MEP and the MIP is confirmed, the link connectivity of one MEP to another MP is checked by sending LBM messages to specified equipment and monitoring the LBR messages in response, and the LBM is a main means for verifying whether the network is recovered.

A system administrator may configure MEPs to issue one or more LBMs, initiated by one MEP, with specified destination address, priority, and drop indication parameters. The destination address is an independent MAC address of other MPs that belong to the same MA as the sending MEP.

The loopback protocol is accomplished by an MEP loopback initiator and an MP loopback responder in the MEP or MHF. After receiving LBM, MP loop responder arriving at destination address first detects its validity, if source address of LBM is multicast address (not single MAC address), or destination address is not matched with MAC address of receiving MP, MP discards the LBM message, if detection is passed, receiving MP takes source address of LBM as destination address, generates an LBR to send to MEP initiating LBM.

Link trace Message (Linktrace Message LTM) and Link trace response (Linktrace Reply LTR)

An LTM is a CFM PDU initiated by an MEP to trace the path from MIP to eventually a destination MAC address until the LTM reaches its destination MEP or can no longer be forwarded. The MP in each path yields a LTR. Calculating path information to a designated MP device by sending LTM messages to the designated device and listening for responsive LTR messages from pathway devices is one of the main means to check for points of failure of the network.

Basic function of CFM

The CFM main functions are path discovery, fault detection, fault validation and isolation, fault notification and fault recovery. The detection and management of the CFM to realize the Ethernet are based on the interaction of two-layer protocol messages, for the discovery principle of link failure, the process can be simplified to that a device designated by an administrator periodically sends CFM PDU (CCM) and receives the CFM PDU by another designated device, if the CFM PDU is not received within a specified time, the link between the two designated devices is considered to have a problem, and the link only comprises a two-layer link and the following layers. The fault location method includes loopback (lbm) and linktrace (ltm) to locate the fault and error.

Path discovery

The path discovery function uses the Linktrace protocol to determine a path to a destination MAC address, starting with one MEP, and going from MIP to MIP, and from MEP to MEP. This destination address may be a MIP, a MEP, or any other unicast MAC address. Linktrace Message (LTM) is a multicast Message that starts from one MEP, goes to its neighboring MIPs, then goes from MIP to MIP, and goes to the final MEP. Each MIP and final MEP on the path will respond to a unicast Linktrace Replies (LTR) to the MEP that originally initiated the LTM. The LTM needs to be triggered by the operation of the administrator, and the message obtained by the response is classified and checked by the original MEP.

Fault detection

The fault detection function uses the continuity check protocol to send CCM messages to detect connectivity faults and unintended connectivity between service instances. Each MEP sends CCM periodically in a multicast mode to inform the identity of the MEP and the MA to which the MEP belongs, meanwhile, CCM messages received from other MEPs are tracked, all connectivity faults can cause errors of CCM information, the received CCM information can possibly be different from the actual configuration information of the MEP, and therefore, the CCM status information tracking is very useful for the administrator to check.

Fault validation and isolation

Fault validation and isolation is an administrative action that is typically performed after fault detection. The failure confirmation is used to confirm whether the connection was successfully started or restored. The administrator performs the failure confirmation using a Loopback protocol (Loopback protocol). The MEP may send a unicast Loopback Message (LBM) to an MEP or MIP in the MA, and the unicast destination MAC addresses may be obtained from the CCM (only the MEP) or LTM/LTR (MEP or MIP). The MP receiving the LBM generates a unicast loopback response (LBR) to send to the MEP initiating the LBM. The initial MEP records information about the response LBR for administrator review.

Fault notification

The failure notification is sent by the MEP that detects the connectivity failure, and the MEP considers that the failure occurs, possibly because the expected CCMs are not received, or invalid CCMs are received, or the received CCMs carry an alarm message of the failure of the relevant bridge port.

Fault recovery

The recovery from the failure can be done by a network administrator, such as correcting a configuration error, or partially replacing the failure.

In summary, the embodiments of the present invention relate to a network communication technology, and in particular, to a method for quickly locating a failure point based on an OTN link. The invention provides a method for rapidly positioning fault points based on an OTN link, which can detect fault points on the subsection and the whole section of the OTN link in a mode of directly sending a detection message and can efficiently find out which section of the link has problems.

It is understood that the system provided by the embodiment of the present invention corresponds to the method provided by the embodiment of the present invention, and the explanation, the example and the beneficial effects of the related contents can refer to the corresponding parts in the method.

The embodiment of the application also provides an electronic device, which comprises a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory complete mutual communication through the communication bus,

a memory for storing a computer program;

the processor is used for realizing the method for rapidly positioning the fault point of the OTN link when executing the program stored in the memory;

the communication bus mentioned in the electronic device may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The communication bus may be divided into an address bus, a data bus, a control bus, etc.

The communication interface is used for communication between the electronic equipment and other equipment.

The Memory may include a Random Access Memory (RAM) or a Non-Volatile Memory (NVM), such as at least one disk Memory. Optionally, the memory may also 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), and the like; the Integrated Circuit may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), or other Programmable logic devices, discrete Gate or transistor logic devices, or discrete hardware components.

In another embodiment provided by the present application, there is also provided a computer program product containing instructions, which when run on a computer, causes the computer to execute the method for quickly locating a failure point of any OTN link in the above embodiments.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the application to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website site, computer, server, or data center to another website site, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A method for rapidly positioning a fault point of an OTN link is characterized by comprising the following steps,

2. The method for fast locating the failure point of the OTN link according to claim 1, wherein:

wherein, in the protocol in step 3, 5 errors are defined according to the receiving situation of the CCM:

3. A computer-readable storage medium, storing a computer program which, when executed by a processor, causes the processor to carry out the steps of the method according to any one of claims 1 to 2.

4. A computer device comprising a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of the method according to any one of claims 1 to 2.