WO2018153314A1

WO2018153314A1 - Method for positioning lsp with error and pcc and pce

Info

Publication number: WO2018153314A1
Application number: PCT/CN2018/076592
Authority: WO
Inventors: 祝沈财
Original assignee: 中兴通讯股份有限公司
Priority date: 2017-02-22
Filing date: 2018-02-13
Publication date: 2018-08-30
Also published as: CN108462641A

Abstract

Disclosed is a method for positioning a label switched path (LSP) with an error, and the method comprises: a path computation client (PCC) receiving at least one path computation element communication protocol error (PCErr) message; the PCErr message carrying at least one piece of identification information about a label switched path (LSP) with an error; and the PCC determining, according to the received PCErr message, the LSP with an error. Further disclosed are a PCC and a path computation element (PCE).

Description

Method for locating LSPs with errors and PCC and PCE

Technical field

The present disclosure relates to the field of communications technologies, and in particular, to a method for locating an errored Label Switched Path (LSP), a Path Computation Client (PCC), and a Path Computation Element (PCE). ).

Background technique

The PCC is used to process all path calculation requests in one router, or to coordinate path calculation requests of multiple routing domains by PCEs of multiple domains. The PCE is generally referred to as a path computation server. In contrast, the requester of the path calculation is called a path computation client. When the PCE receives the PCC request (PCE Request, PCReq), the PCE calculates the existing network topology information. An end-to-end path that satisfies the constraints and policies, and returns the path calculation result to the PCC, thereby completing a path calculation.

RFC 5440 states that PCE is a new computing technology that deploys one or several devices with computing functions in a network domain, dedicated to computing paths. The PCC resides in the module to calculate the path, and is used to send the calculation request message and the processing result. The PCC and the PCE implement the interaction through the Path Computation Element Communication Protocol (PCEP). When an error occurs between the PCC and the PCE, the peer is notified by a transmission path calculation unit communication protocol error (PCEP Error, PCErr) message. The format of the PCErr message and the path calculation unit error protocol PCEP-ERROR (PCEP Error object) format are defined on the PCEP protocol.

Summary of the invention

The following is an overview of the topics detailed in this document. This Summary is not intended to limit the scope of the claims.

The embodiments of the present disclosure provide a method for locating an LSP that has an error, and a PCC and a PCE, which can locate an erroneous LSP when an LSP error occurs.

An embodiment of the present disclosure provides a method for locating an erroneous label switched path LSP, where the method includes:

The path calculation client PCC receives at least one PCErr message; the PCErr message carries at least one identification information of the label switched path LSP that has an error;

The PCC determines an LSP that has an error according to the received PCErr message.

In the above solution, the PCErr message includes an additional type-length-valued TLV in at least one PCEP-ERROR, and the TLV carries identification information of an LSP that has an error.

In the foregoing solution, the identifier information of the LSP that is in error includes: a path name of the LSP that has an error;

Determining, by the PCC, the LSP that is in error according to the received PCErr message, the PCC acquiring the error according to the TLV corresponding to the at least one LSP that has an error included in the received PCErr message. The path name of the LSP, and the LSP with the error is determined according to the path name of the LSP where the error occurs.

In the foregoing solution, after the PCC determines that an LSP has an error, the method further includes: deleting, by the PCC, the LSP that is in error.

The embodiment of the present disclosure further provides another method for locating an error-prone label switched path LSP, where the method includes:

The path calculation unit PCE receives the state information of the label switching path LSP reported by the path calculation client PCC;

After the PCE determines that the LSP is in error based on the status information of the LSP, sends at least one path calculation unit communication protocol error PCErr message to the PCC; the PCErr message carries at least one identifier of the LSP that is in error. .

In the above solution, the PCErr message includes an additional type-length-value TLV in the at least one path calculation unit communication protocol error object PCEP-ERROR, and the TLV carries identification information of an LSP with an error.

In the above solution, after the PCE determines that the LSP is in error, the method further includes: the PCE modifying the LSP with an error.

The embodiment of the present disclosure further provides a path calculation client PCC, where the PCC includes: a first receiving module and a determining module;

The first receiving module is configured to receive at least one path calculation unit communication protocol error PCErr message; the PCErr message carries at least one identification information of the label switching path LSP that has an error;

The determining module is configured to determine an LSP in which the error occurred based on the received PCErr message.

The determining module is configured to obtain, according to the received TLV corresponding to the at least one LSP that is in error, the path name of the LSP that is in error, according to the path name of the LSP that is in error , determining the LSP with the error.

In the above solution, the PCC further includes: a first processing module;

The first processing module is configured to delete or modify the LSP that has an error after the determining module determines the LSP that has an error.

The embodiment of the present disclosure further provides a path calculation unit PCE, where the PCE includes: a second receiving module and a second processing module;

The second receiving module is configured to receive the path information of the label switching path LSP reported by the client PCC.

The second processing module is configured to: after determining that the LSP is faulty based on the status information of the LSP, send, to the PCC, at least one path calculation unit communication protocol error PCErr message; the PCErr message carries at least one LSP with an error Identification information.

In the above solution, the second processing module is further configured to modify the LSP with an error after determining that the LSP has an error.

Embodiments of the present disclosure also provide a computer readable storage medium storing computer executable instructions that, when executed by a processor, implement any of the methods described above.

The embodiment of the present disclosure provides a method for locating an erroneous label switched path LSP, and a PCC and a PCE, where the PCC receives at least one PCErr message; the PCErr message carries at least one identifier of the LSP that has an error; The PCC determines an LSP that has an error according to the received PCErr message. In this way, the wrong LSP can be located when an LSP error occurs.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

DRAWINGS

Figure 1 is a schematic diagram of a PCEP-ERROR object format;

2 is a flow chart of a first example of a method for locating an erroneous LSP according to an embodiment of the present disclosure;

3 is a schematic diagram of a path name TLV format in an embodiment of the present disclosure;

4 is a flow chart of a second example of a method for locating an erroneous LSP according to an embodiment of the present disclosure;

5 is a flowchart of a third example of a method for locating an LSP that has an error according to an embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram of a path calculation client PCC according to an embodiment of the present disclosure;

FIG. 7 is a schematic structural diagram of a path calculation unit PCE according to an embodiment of the present disclosure.

detailed description

FIG. 1 is a schematic diagram of a PCEP-ERROR object format. As shown in FIG. 1 , the PCEP-ERROR object format may include: reserved bits Reserved, flagged Flags, error type Error-Type, error value Error-value, and additional TLV Optional TLVs. Among them, Reserved reserves a bit that will not be used temporarily for expansion and other operations; Flags is used to record some status flag bits; Error-Type is used to indicate between PCC and PCE carried in the current PCEP-ERROR object. The error type; Error-value further refers to the type of error between PCC and PCE as special error, general error, etc.; Optional TLVs are used to carry additional error information.

Among them, PCE can be divided into stateless mode and stateful mode. The Internet Engineering Task Force (IETF) standard protocol [RFC8231] describes stateful PCE as PCC and PCE. The PCC sends a Path Computation LSP State Report (PCRpt) real-time synchronization LSP status to the PCE through the Label Switched Path (LSP) information. After the LSP is saved, the PCE can calculate the optimal path optimization result and send the Path Computation LSP Update Request (PCUpd) to the PCC to modify the existing LSP attributes and paths on the PCC. The protocol extends the format of the PCErr message for the new message content. The details are as follows:

The definition and description of the PCErr message in the above two protocol documents solve the following problems:

1. The error response of the Open message is implemented by carrying the OPEND object in the PCErr;

2. The error response of the PCReq message is implemented by carrying the RP object in the PCErr;

3. The error response of the PCUpd message is implemented by carrying the SRP object in the PCErr.

However, if an error occurs in the PCRpt message reporting the LSP status, the existing PCErr message will not accurately indicate the specific LSP corresponding to the error. The PCC cannot receive the error message for the LSP.

The schemes in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present disclosure.

First example

2 is a flowchart of a first example of a method for locating an LSP that has an error according to an embodiment of the present disclosure. As shown in FIG. 2, the method includes:

Step 200: The PCE receives status information of the LSP reported by the PCC.

In this step, before the PCE receives the status information of the LSP reported by the PCC, the PCE first uses the existing network topology information to create an end-to-end path for the PCC that satisfies the constraints and policies. For example, the PCE creates an SR tunnel for the PCC. The PCE sends a message to the PCC to establish an SR tunnel through the PCInitiate message. The PCE records the current LSP status and the path attribute is the SR type. The PCC receives the PCInitiate message and processes it, but the PCC creates the LSP for the PCE. It is understood to be an ordinary RSVP tunnel. After the PCC creates an RSVP tunnel, it reports the LSP status created by the current PCC through the PCRpt message and the label tunnel type is RSVP in the PCRpt message.

Step 201: After the PCE determines that the LSP is in error based on the status information of the LSP, send, to the PCC, at least one PCErr message; the PCErr message carries at least one identifier information of an LSP that has an error.

In this step, after the PCE determines that the LSP is in error, the PCE may further include: the PCE modifying the LSP with the error.

The PCErr message may include an additional type-length-value TLV in the at least one PCEP-ERROR object, where the TLV carries identification information of an LSP that has an error.

In actual implementation, the identifier information of the LSP that has an error may include: a path name of the LSP where the error occurs.

The LSP information can be carried by the PCEP-ERROR object included in the PCErr message defined in the RFC5440 communication protocol. The RFC5440 communication protocol defines that the PCEP-ERROR object can carry an additional TLV to further indicate the error information. However, the protocol does not further define how the PCEP-ERROR object in the PCErr message carries the LSP information when an LSP error occurs. The Path-Name (Symbolic Path Name) TLV is defined in the protocol [RFC8231] to describe the unique name of the LSP, and the path name Path-Name is used to indicate the identification information of an LSP. Therefore, in the embodiment of the present disclosure, the Path-Name TLV carrying the error LSP in the PCEP-ERROR object may be used to indicate the LSP in which the error occurs, and the Path-Name is used as the identifier information of the LSP in which the error occurs.

In actual implementation, the error object list <error-obj-list> is used in the PCErr message to carry the error information between the PCC and the PCE. When an LSP error occurs, the <error-obj-list> in a PCErr message can carry the error information of multiple different LSPs at the same time, or carry different error information of the same LSP. Therefore, when an LSP error is indicated by an additional TLV carried by the PCEP-ERROR object, each PCEP-ERROR object in the <error-obj-list> carries the Path-Name TLV of the LSP, which is used to indicate an LSP error message.

For example, in the PCEP-ERROR object format shown in FIG. 1 , the PCEP-ERROR object may be extended to carry additional TLV (Optional TLVs) information for information supplementation of error information, and the embodiment of the present disclosure defines PCEP. The -ERROR object describes the specific LSP information corresponding to the erroneous LSP by carrying the Path-Name TLV shown in FIG.

3 is a schematic diagram of a path name TLV format in the embodiment of the present disclosure. As shown in FIG. 3, the LSP information may be encoded into a Path-Name TLV format, including: Type Type, Length Length, and Path Name Path-Name; The error type indicating the LSP that currently has an error; Length is used to indicate the size of the current TLV, and the size of the Length is variable according to the TLV to be expressed, and the specific case; Path-Name is used to identify an error. LSP.

Exemplarily, after the PCE receives the PCR pt message reported by the PCC, the PCE checks whether the local LSP information matches the LSP information carried in the PCR pt, and finds the LSP type (SR type) created by the PCE and the LSP type (RSVP type) created by the PCC. Inconsistent, the PCE determines that the LSP created at this time has an error, and sends a PCErr message to the PCC according to the protocol (for example, the error type Error Type=20 in the PCErr message, the error value Error value=2) to inform the PCC that the LSP type is incorrect. The PCErr message carries the Path-Name of the LSP with the error. At the same time, the PCE modifies the LSP with the local error.

Step 202: After receiving the at least one PCErr message, the PCC determines an LSP that has an error according to the received PCErr message.

The identification information of the LSP in which the error occurs may include: the path name of the LSP in which the error occurred. The PCC obtains the path name of the LSP in which the error occurred according to the TLV corresponding to the LSP that is in error, and the PCC determines the LSP that is in error according to the path name of the LSP where the error occurred.

In this step, after determining the LSP that is in error, the method may further include: deleting, by the PCC, the LSP that is in error.

It can be understood that after the PCCrr message is received by the PCC, the error type carried in the message is an LSP type error according to the error type of the message type included in the PCEP-ERROR object, and then the error LSP carried in the message can be correspondingly The Path-Name TLV obtains the Path-Name of the LSP and locates the error LSP according to the obtained Path-Name.

In the actual implementation, when the PCErr message does not have a Path-Name, or the corresponding LSP is not found according to the obtained Path-Name, the PCC discards the PCErr message; when the corresponding LSP is found according to the obtained Path-Name, the PCC deletes Or modify the local LSP. For example, when the LSP type (RSVP type) created by the PCC does not match the LSP type (SR type) created by the PCE, the PCC may delete the locally created LSP (that is, delete the RSVP tunnel) or according to the error information carried in the PCErr message. Modify the corresponding LSP status information.

If an error occurs in the PCRpt message of the LSP status reported by the PCC, the PCC cannot accurately locate the specific LSP corresponding to the error from the received PCErr message. The PCCrr message cannot be processed by the PCC for the specific LSP. In addition, in the case of some LSP errors, it is not necessary to locate the LSP. For example, the LSP error types defined in the current protocol are common. For example, the Explicit Route Object (ERO) is missing. Generally, all LSPs are used. Nothing, it is not necessary to locate the wrong LSP at this time.

On the other hand, the protocol [RFC8281] describes that the PCE can send a Path Computation LSP Initiate message to the PCC as needed to actively trigger the establishment of a tunnel. For example, if an application wants to create a new tunnel with a specific constraint, or if the existing tunnel bandwidth cannot meet the requirements, create a new tunnel for load sharing.

The draft [draft-ietf-pce-segment-routing-11] describes the path routing (SR) between the PCC and the PCE by extending the ERO information and the path setup type (PST) information. Type tunnel creation and status escalation.

Through the extension of the SR function, it is necessary for the LSP error notified by the PCErr to be specific to which LSP error. Here, the specific error information includes the LSP information in which the error occurred, and then the corresponding corrective action is taken.

In the embodiment of the present disclosure, the path calculation client PCC receives at least one path calculation unit communication protocol error PCErr message; the PCErr message carries at least one identification information of the label switching path LSP that has an error; the PCC according to the received The PCErr message determines the LSP where the error occurred. At present, the PCC interaction mode defined by the communication protocol can only know that an LSP type error occurs, but the PCC cannot locate which LSP is faulty, and it is impossible to further process the LSP with the error. In the disclosed embodiment, the PCC may modify or re-localize the local LSP error after the faulty LSP is located according to the identifier information of the LSP that is carried in the PCErr message.

Second example

In order to further embodies the purpose of the present disclosure, further exemplification is made on the basis of the first example of the present disclosure.

FIG. 4 is a flowchart of a second example of a method for locating an LSP that has an error according to an embodiment of the present disclosure. As shown in FIG. 4, the method includes:

Step 400: The PCC receives at least one PCErr message; the PCErr message carries identifier information of at least one LSP that has an error.

In an actual implementation, the identifier information of the LSP that is in error may include: a path name of the LSP that has an error.

Step 401: The PCC determines an LSP that has an error according to the received PCErr message.

In an actual implementation, when the identifier information of the LSP that is in error includes the path name of the LSP in which the error occurs, the PCC obtains the path of the LSP in which the error occurs according to the TLV corresponding to the LSP that is in error of the LSP that is included in the received PCErr message. Name, the PCC determines the LSP with the error based on the path name of the LSP where the error occurred.

Third example

FIG. 5 is a flowchart of a third example of a method for locating an LSP that has an error according to an embodiment of the present disclosure. As shown in FIG. 5, the method includes:

Step 500: The PCE receives status information of the LSP reported by the PCC.

Step 501: After the PCE determines that the LSP is in error based on the LSP status information, the PCErr message is sent to the PCC. The PCErr message carries the identifier information of the at least one LSP that is in error.

Fourth example

For the method of the embodiment of the present disclosure, the embodiment of the present disclosure further provides a path calculation client PCC. FIG. 6 is a schematic structural diagram of a path calculation client PCC according to an embodiment of the present disclosure. The client includes: a first receiving module 600 and a determining module 601; wherein

The first receiving module 600 is configured to receive at least one PCErr message; the PCErr message carries identifier information of at least one LSP that has an error.

The determining module 601 is configured to determine an LSP in which an error occurs based on the received PCErr message.

The identifier information of the LSP that is in error may include: a path name of the LSP that has an error.

The determining module 601 is configured to obtain, according to the received TLV corresponding to the at least one LSP that is in error in the PCErr message, the path name of the LSP that is in error, and the PCC is faulty according to the The path name of the LSP to determine the LSP with the error.

The path calculation client may further include: a first processing module;

In practical applications, the first receiving module 600 and the determining module 601 can be configured by a central processing unit (CPU), a microprocessor (Micro Processor Unit, MPU), and a digital signal processor (Digital Signal Processor) located in the PCC. , DSP), or Field Programmable Gate Array (FPGA) implementation.

Fifth example

For the method of the embodiment of the present disclosure, the embodiment of the present disclosure further provides a path calculation unit PCE. FIG. 7 is a schematic structural diagram of a path calculation unit PCE according to an embodiment of the present disclosure. As shown in FIG. 7, the path calculation is performed. The unit includes: a second receiving module 700 and a second processing module 701; wherein

The second receiving module 700 is configured to receive status information of the LSP reported by the PCC.

The second processing module 701 is configured to: after determining that the LSP is faulty based on the status information of the LSP, send at least one PCErr message to the PCC; the PCErr message carries identifier information of at least one LSP that has an error.

The second processing module 701 may be further configured to modify the LSP that has an error after determining that the LSP has an error.

In practical applications, the second receiving module 700 and the second processing module 701 can be implemented by a CPU, an MPU, a DSP, an FPGA, or the like located in the PCE.

Those of ordinary skill in the art will appreciate that all or some of the steps, systems, and functional blocks/units of the methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. In a hardware implementation, the division between functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be composed of several physical The components work together. Some or all of the components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer readable medium, which may include computer storage media (or non-transitory media) and communication media (or transitory media). As is well known to those of ordinary skill in the art, the term computer storage medium includes volatile and nonvolatile, implemented in any method or technology for storing information, such as computer readable instructions, data structures, program modules or other data. Sex, removable and non-removable media. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridge, magnetic tape, magnetic disk storage or other magnetic storage device, or may Any other medium used to store the desired information and that can be accessed by the computer. Moreover, it is well known to those skilled in the art that communication media typically includes computer readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transport mechanism, and can include any information delivery media. .

The above description is only for the exemplary embodiments of the present disclosure, and is not intended to limit the scope of the disclosure.

Industrial applicability

Claims

A method for locating an erroneous label switched path LSP includes:

The path calculation client PCC receives at least one path calculation unit communication protocol error PCErr message; the PCErr message carries at least one error indication label exchange path LSP identification information (400);

The PCC determines an LSP (401) in which an error occurs based on the received PCErr message.
The method of claim 1 wherein said PCErr message includes an additional type-length-valued TLV of at least one path computation unit communication protocol error object PCEP-ERROR, said TLV carrying an error ID information of the LSP.
The method according to claim 2, wherein the identification information of the LSP in which the error occurs includes: a path name of the LSP in which the error occurs;

Determining, by the PCC, the LSP (401) that the error occurs according to the received PCErr message, including: the PCC acquiring the TLV corresponding to the at least one LSP that is in error according to the received PCErr message. The path name of the LSP in which the error occurs is determined according to the path name of the LSP in which the error occurs.
The method according to claim 1 or 3, wherein after the PCC determines that an LSP (401) that an error has occurred, the method further comprises: the PCC deleting or modifying the LSP with an error.
A method for locating an erroneous label switched path LSP includes:

The path calculation unit PCE receives the status information (500) of the label switched path LSP reported by the path calculation client PCC;

After the PCE determines that the LSP is in error based on the status information of the LSP, sends at least one path calculation unit communication protocol error PCErr message to the PCC; the PCErr message carries at least one identifier of the LSP that is in error. (501).
The method of claim 5, wherein the PCErr message includes an additional type-length-value TLV of at least one path computation unit communication protocol error object PCEP-ERROR, the TLV carrying an error ID information of the LSP.
The method according to claim 5, wherein after the PCE determines that the LSP has an error, the method further comprises: the PCE modifying the LSP with an error.
A path calculation client PCC, comprising: a first receiving module (600) and a determining module; wherein

The first receiving module (600) is configured to receive at least one path calculation unit communication protocol error PCErr message; the PCErr message carries at least one identification information of the label switching path LSP that has an error;

The determining module (601) is arranged to determine an LSP in which the error occurred based on the received PCErr message.
The PCC of claim 8, wherein the PCErr message includes an additional type-length-value TLV of at least one path computation unit communication protocol error object PCEP-ERROR, the TLV carrying an error ID information of the LSP.
The PCC according to claim 9, wherein the identification information of the LSP in which the error occurs includes: a path name of the LSP in which the error occurs;

The determining module (601) is configured to acquire, according to the received TLV corresponding to the at least one LSP that is in error, the path name of the LSP that is in error, according to the LSP that is in error The path name to determine the LSP with the error.
A PCC according to claim 8 or 10, further comprising: a first processing module;

The first processing module is configured to delete or modify the LSP with an error after the determining module (601) determines the LSP with an error.
A path calculation unit PCE includes: a second receiving module (700) and a second processing module (701); wherein

The second receiving module (700) is configured to receive status information of the label switching path LSP reported by the client PCC.

The second processing module (701) is configured to: after determining that the LSP is faulty based on the status information of the LSP, send at least one path calculation unit communication protocol error PCErr message to the PCC; the PCErr message carries at least one item The identification information of the wrong LSP.
The PCE of claim 12, wherein the PCErr message includes an additional type-length-value TLV of at least one path computation unit communication protocol error object PCEP-ERROR, the TLV carrying an error ID information of the LSP.
The PCE of claim 12, wherein the second processing module (701) is further configured to modify the LSP that is in error after determining that the LSP has an error.
A computer readable storage medium storing computer executable instructions that, when executed by a processor, implement the method of any of claims 1-4.
A computer readable storage medium storing computer executable instructions that, when executed by a processor, implement the method of any of claims 5-7.