WO2007118429A1

WO2007118429A1 - Method and apparatus for detecting backward defect indication path condition

Info

Publication number: WO2007118429A1
Application number: PCT/CN2007/001243
Authority: WO
Inventors: Shuyou Dong; Wenyang Lei
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-04-18
Filing date: 2007-04-16
Publication date: 2007-10-25
Also published as: CN1852183A

Abstract

The invention provides a method and apparatus for detecting status of backward defect indication path. The said method includes following procedures: sends the connectivity message to the receiver in backward defect indication path according to the scheduled time interval; the said receiver receives the said connectivity message; when the receiver end timer is reached, if receiver does not receive the connectivity message, a failure has occurred in backward defect indication path. The invention also discloses an apparatus for detecting of backward defect indication path. The said apparatus includes the sending and receiving modules for detecting message. Using technical method of invention, it is no need of configuring mechanism of fault detection singly for BDI path, and uses MPLS OAM mechanism directly for implementing detection of connectivity for BDI path.

Description

Method and device for detecting reverse path indication path state on April 18, 2006, the invention claims to be a Chinese patent office, application number 200610075642.3, and the invention name is "a method and device for detecting reverse defect indication path state" The priority of the Chinese patent application is hereby incorporated by reference in its entirety.

The present invention relates to the field of communications technologies, and in particular, to a method for detecting a state of a reverse defect indicating path. Background technique

In order to determine the connectivity of the Label Switching Path (LSP) in the user plane of the MPLS, measure the utilization of the network and measure the performance of the network, and quickly perform protection switching when the link is faulty or faulty, so that The Service Level Agreements (SLAs) signed with customers provide services, and the MPLS layer needs to provide an OAM mechanism that is completely independent of any upper or lower layers.

Using this MPLS OAM mechanism, it is possible to effectively detect, confirm, and locate defects originating from the MPLS layer network; report defects and make corresponding processing; and provide a trigger mechanism for protection switching in the event of a failure.

A further introduction to the background of MPLS OAM functional requirements can be found in ITU-T Recommendation Y.1710.

There are four main types of MPLS OAM messages. The format of each message type is as follows. l. OAM CV packet

OAM connectivity detection (CV-Connectivity Verification) The LSP connectivity detection is performed by the ingress (source) transmission of the LSP and the reception (sink) of the LSP.

2. OAM FFD packet

OAM FFD (Fast Failure Detection) is the same as the CV message.

The connectivity detection is performed in the manner in which the ingress (source) of the LSP is transmitted and the egress (sink) is received.

Compared with the CV packet, the FFD packet has one byte of frequency information. CV message collection The fixed Is transmission period is used, and the FFD message can support multiple transmission frequencies such as 10ms, 20ms, 50ms^100ms, 200ms, 500ms, etc., and the supported frequency values can be changed according to requirements.

3. 0AM FDI message

The OAM Forward Defect Indication (FDI) packet is used by the upstream node of the LSP to advertise the defect information to the egress node of the LSP.

4. OAM Backward Defect Indication (BDI) packet The OAM BDI packet is used by the outbound node of the LSP to notify the ingress of the LSP through the reverse channel after discovering the LSP defect.

Referring to Figure 1, the basic detection function of MPLS OAM is mainly the interaction process of connectivity detection. It can be described as follows:

MPLS OAM detects the connectivity of a single LSP. The device sends a CV FFD packet to the source. The packet is sent to the sink through the detected LSP. The sink determines the type, frequency, and path of the LSP. The TTSI (Terminal Termination Source Identifier) information is correct, and the number of correct and incorrect packets received during the detection period is calculated, so that the connectivity of the LSP is monitored at any time, and when the LSP is defective, it is quickly detected. Defects and analyze the type of defect.

At the same time, when configuring the OAM function of the LSP, bind it to a reverse channel.

The non-MPLS path of the LSP is sent to the source through the reverse channel. The BDI packet carrying the defect information is sent to the source through the reverse channel. The source device knows the defect status in time and configures the protection correctly. When the group is triggered, the corresponding switching is triggered. It should be noted that the reverse channel carrying BDI may be of the following three types:

A dedicated reverse LSP. The only reverse LSP corresponding to the forward LSP is relatively stable, but it may cause waste of resources.

A shared reverse LSP. A number of forward LSPs share a reverse LSP. All the LSPs returning BDI packets pass through this reverse LSP. This method reduces resource waste. However, when multiple forward LSPs are simultaneously defective, this reverse LSP There may be congestion on it.

Non-MPLS return path. This method may pose a security risk. For example, a malicious user may create a BDI packet to be sent to the source of the detected LSP, causing unnecessary Interrupted. To avoid this hazard, additional security confirmations should be configured for BDI messages. For example, the TTSI is configured for the OAM, so that the TTSI information of the detected LSP can be carried in the BDI packet, so as to verify the validity of the BDI packet.

As can be seen from the above analysis, the fault information of the MPLS OAM needs to be advertised in the manner shown. For BDA notification, the premise is that the path of the BDI message is unobstructed. If the BDI message cannot reach the source due to the path failure of the BDI, the entire fault detection mechanism fails. In the case of BDI path sharing, if the shared path fails, the fault detection of all forward LSPs will be invalidated. This situation is more serious.

Therefore, it is necessary to provide a mechanism for detecting whether the BDI path is unobstructed. The prior art employs a method of separately configuring the fault detection function for the BDI path. For example: If the BDI message is forwarded through the IP path, the BDI path is detected by detecting whether the normal IP path is normal. If the BDI message is transmitted through the MPLS LSP, the LSP needs to be detected. The method is ordinary MPLS OAM detection.

With the above prior art solution, the configuration workload is increased, the deployment is troublesome, and the BDI fault detection and the fault detection of the LSP or the IP need to be bound. Summary of the invention

Embodiments of the present invention provide a method and apparatus for detecting a BDI path state by a reverse defect.

Embodiments of the present invention provide a reverse defect indication path state detection method, where the method includes:

The transmitting end periodically sends a connectivity detection packet to the receiving end on the reverse defect indication path; the receiving end receives the connectivity detection packet, and when the timing of the receiving end arrives, the receiving end does not receive the packet. The connectivity detection packet determines that the reverse defect indication path is faulty.

The embodiment of the invention provides a path state detecting device, which comprises a detecting message sending module.

The detection packet sending module is configured to periodically send a connectivity detection message to the corresponding receiving end on the reverse defect indication path.

Preferably, the transmitting module includes a timer module and reverse defect indication path connectivity Detecting a transmitting submodule;

The timer module is configured to set a timing duration for the reverse defect indication path, and the reverse defect indication path connectivity detection sending submodule is configured to: when the timing duration of the reverse defect indication path arrives, A connectivity detection is generated, and the connectivity detection packet is sent through a corresponding reverse defect indication path.

Preferably, the device further comprises a detection message receiving module,

The detection packet receiving module is configured to receive the connectivity detection packet, and if the predetermined timing duration of the receiving end arrives, the connectivity detection is not received, and the reverse defect is determined. Indicates that the path has failed.

Another path state detecting apparatus provided by the embodiment of the present invention includes: detecting a message receiving module;

The detection packet receiving module is configured to receive the connectivity detection packet, and if the receiving terminal does not receive the connectivity detection packet when the timing of the receiving end arrives, determine the reverse The defect indicates that the path has failed.

Preferably, the detection message receiving module comprises a sliding timer module and a reverse defect indicating path connectivity detecting receiving submodule;

The sliding timer module is configured to set a timing duration for the reverse defect indication path, where a timing duration of the receiving end is greater than a timing duration of the corresponding sending end;

The reverse defect indication path connectivity detection receiving submodule is configured to receive the connectivity test J1.

It can be seen from the above technical solution of the present invention that when the reverse defect indication BDI is performed, the message flow of the MPLS OAM fault detection is extended, and the path detection packet is periodically sent on the path of the BDI, and the receiving end is based on a certain time interval. The number of received probe packets determines whether the BDI path is faulty. It is not necessary to separately configure the fault detection mechanism for the BDI path. Instead, the MPLS OAM mechanism is used to automatically detect the BDI path connectivity. Therefore, the workload of the tester is greatly reduced, the test procedure can be simplified, and the reliability and efficiency can be improved. DRAWINGS

Figure 1 shows the basic process of MPLS OAM interaction detection;

2 is a device diagram of detecting a path state in an embodiment of the present invention; FIG. 3 is a flowchart of sending a reverse fault indication path detection message according to an embodiment of the present invention;

FIG. 4 is a flowchart of receiving a message by using a reverse defect indication path in the embodiment of the present invention. detailed description

The invention is further illustrated by the following figures and examples, but not by way of limitation.

In the embodiment of the present invention, the message flow of the MPLS OAM fault detection is extended, and the path detection packet is periodically sent on the path of the BDI. If the receiving end does not receive the specified number of detection packets within a certain time interval, the BDI path is considered to be faulty. .

The specific steps of the reverse defect indication path state detection method provided in the embodiment of the present invention are as follows:

Referring to FIG. 2, a reverse defect indication path state detecting device is provided. The device includes: a detecting message sending module or/and a detecting message receiving module;

The detecting message sending module is configured to send, by the sending end of the reverse defect indicating path, a connectivity detecting message to the receiving end of the reverse defect indicating path on the reverse defect indicating path; the detecting message receiving module, The receiving end receives the connectivity detection packet, and if the receiving end still does not receive the connectivity detection packet when the timing of the receiving end arrives, the reverse defect indication path is considered to appear. malfunction.

The detection message sending module includes a reverse defect indication (BDI) processing module and a timer module, and the BDI processing module has a BDI CV (BDI Connectivity Verification) transmission sub-module;

The timer module is configured to set a timing duration for the reverse defect indication path, and the reverse defect indication path connectivity detection sending submodule is configured to generate when the timing duration of the reverse defect indication path arrives A connectivity detection packet is sent, and the connectivity detection packet is sent by the reverse defect indication path corresponding to the timing duration.

The detection message receiving module includes a sliding timer module and a reverse defect indication path connectivity detection BDI CV receiving submodule;

The sliding timer module is configured to set a timing time for the reverse defect indication path The timing of the receiving end is greater than the corresponding timing of the sending end; the reverse defect indicating path connectivity detecting and receiving submodule is configured to receive the connectivity detecting message.

Referring to FIG. 3, the process of sending a reverse defect indication path detection packet in the embodiment of the present invention includes the following steps:

Step 101: Set a timing duration for the reverse defect indication path at the sending end, and the timer module stores timing information of all LSPs that have enabled BDI path detection, and can set different timing durations for BDI detection paths corresponding to different LSPs. . Since the connectivity check of the BDI path is a non-real-time tight detection, the duration of the timing can be relatively long.

Step 102: When the timing duration arrives, a connectivity detection message is generated. When some

When the timing of the LSP arrives, a timer interrupt message is generated, and the message includes the information of the LSP. The reverse defect indicates the path connectivity detection. After receiving the interrupt message, the BDI CV sending sub-module extracts the information of the LSP. Construct reverse defect indication path connectivity detection BDI CV detection message.

The BDI CV detection packet can be used in two ways:

1. Define a new message type

Define a new message type called BDI-CV with the message format as follows:

Function type: packet type, 0x05 represents reverse defect indication path connectivity detection BDI CV message

Reserved: Reserved field

Type: Action type, can indicate two actions, namely BDI-CV detection and BDI-CV stop detection

TTSI: LSP ID, if TTSI is not required, this field is padded with 0x00

Padding: padding field BIP16: Message checksum

2. Extend BDI messages

Add BDI connectivity detection information to the BDI message. The message format is as follows:

The type field indicates the action type, and the valid value is 0x01, which indicates the BDI CV detection message. If the value of type is 0, it means that it is a normal BDI failure notification message.

Step 103: The connectivity detection message BDI CV is sent by the reverse defect indication path corresponding to the timing duration.

Referring to FIG. 4, the flow chart of the reverse defect indication path detection message receiving end is shown in the following steps: Step 201: Set a timing duration for each reverse defect indication path at the receiving end, and the timing duration is greater than the timing duration of the corresponding sending end. , the duration can be 3 times the transmission period of the text;

Step 202: Start a sliding timer to determine whether the BDI CV detection message is received. The detection of the reverse defect message is performed by using a sliding window at the receiving end of the reverse defect indication path;

Step 203: If the defect detection message is received within the specified timing of the receiving end, the sliding timer is reset.

Step 204: When the timing value of the timer arrives, the BDI CV receiving submodule still does not receive the connectivity detection packet, and the reverse defect indication path is considered to be faulty.

The embodiments of the invention have been described in detail by way of example only, and those of ordinary skill in the art in

Claims

Rights request

A reverse defect indication path state detection method, characterized in that the method comprises:

The method according to claim 1, wherein the sending the connectivity detection packet specifically includes:

Setting a predetermined timing duration for the reverse defect indication path at the sending end, and when the timing duration arrives, generating the connectivity detection packet, and sending the connectivity through the reverse defect indication path Detect the message.

3. The method according to claim 1, further comprising: before the receiving end receives the connectivity detection,

And setting, at the receiving end, a timing duration for the reverse defect indication path, where a timing duration of the receiving end is greater than a corresponding timing duration of the transmitting end.

The method according to any one of claims 1 to 3, wherein the connectivity detection message is a custom ^=艮文.

The method according to any one of claims 1 to 3, wherein the connectivity detection message is an extended reverse defect indication message.

A path state detecting device, characterized in that the device comprises a detecting message sending module,

The detection packet sending module is configured to periodically send a connectivity detection packet to the receiving end of the phase on the reverse defect indication path.

The detecting device according to claim 6, wherein the sending module comprises a timer module and a reverse defect indicating path connectivity detecting and transmitting submodule;

The timer module is configured to set a timing duration for the reverse defect indication path, and the reverse defect indication path connectivity detection sending submodule is configured to: when the timing duration of the reverse defect indication path arrives, Generate connectivity detection packets and pass the corresponding reverse The trap indication path sends the connectivity detection message.

The detecting device according to claim 6 or 7, further comprising a detecting message receiving module;

•

A path state detecting device, wherein the device comprises a detecting message receiving module;

The detecting device according to claim 9, wherein the detecting message receiving module comprises a sliding timer module and a reverse defect indicating path connectivity detecting receiving submodule; Setting a timing duration for the reverse defect indication path, where a timing duration of the receiving end is greater than a timing duration of the corresponding transmitting end;

The reverse defect indication path connectivity detection receiving submodule is configured to receive the connectivity detection packet.