CN100388694C - A loopback test method - Google Patents

Abstract

The invention discloses a loopback test method, which is applicable to a near-end data terminal equipment DTE and a remote DTE for establishing an OAM connection. The loopback test method includes steps: A1, the near-end DTE sends a loopback test start OAM protocol message The OAMPDU informs the remote DTE to start the loopback test, and the remote DTE enters the loopback state; A2, the near-end DTE sends the OAM connection maintenance OAMPDU to the remote DTE, and confirms the remote DTE by recycling the OAM connection maintenance OAMPDU returned by the remote DTE Enter the loopback state, and the near-end DTE enters the loopback state; A3, the near-end DTE sends a loopback test data message to the remote DTE, and determines the link state by retrieving the loopback test data message returned by the remote DTE. The loopback test method provided by the invention can realize the OAM remote loopback test of the existing DTE equipment.

Description

A loopback test method

technical field

The present invention relates to loopback test technology, relate in particular to operation, management and maintenance (OAM, Operations, Administration and Maintenance) remote loopback test method.

Background technique

In order to improve the management function of more complex networks, the Institute of Electrical and Electronics Engineering (IEEE) proposed the OAM standard in the 802.3ah protocol specification. This standard aims to solve the management problems of the last mile network, providing link performance monitoring, Functions such as fault detection and alarm, remote loopback test, and management information database (MIB) variable acquisition. As one of the main functions of OAM, the remote loopback test can be used for link fault detection and performance testing. The regular remote loopback test can ensure the smooth flow of the existing link, and the staged remote loopback test can help Quickly locate specific areas where failures occur.

Commonly, the premise of performing an OAM remote loopback test between two data terminal equipments (DTEs) is that an OAM connection has been established between the near-end DTE and the far-end DTE, that is, the OAM entity of the near-end DTE has discovered The OAM entity of the remote DTE has been established and a stable OAM session has been established with the OAM entity of the remote DTE. This process is usually called the first stage of the OAM session connection. Hereinafter, the OAM entity of the near-end DTE is called the near-end OAM entity for short, and the OAM entity of the far-end DTE is called the far-end OAM entity for short.

In the first stage of the OAM session connection, the near-end OAM entity and the remote OAM entity configure the OAM entities of both parties through the OAM protocol message (OAMPDU), and exchange port function parameters and identifiers. The parameter determines whether to establish an OAM connection with the peer OAM entity. Specific to the OAM remote loopback test function, if the near-end OAM entity requires the remote OAM entity to have the remote loopback test function, that is, the remote end is required to be the controlled end of the remote loopback test, but the remote OAM entity does not have this function. function, the near-end OAM entity will refuse to establish an OAM connection with the remote OAM entity. Correspondingly, only when the remote OAM entity has the remote loopback test function, the near-end OAM entity will establish an OAM connection with the remote OAM entity. , and perform remote loopback tests periodically.

After the OAM connection is established, the near-end OAM entity and the remote OAM entity will periodically send the OAM connection maintenance message INFO_OAMPDU to the peer OAM entity, so as to exchange the OAM information of the near-end DTE and the far-end DTE. Specifically, both the near-end DTE and the remote DTE are configured with an OAM connection timeout timer. If an OAM entity at one end receives an OAM connection maintenance message sent by the peer end before the OAM connection timeout timer at the local end expires, the OAM entity at one end is reset. If the local OAM connection timeout timer expires, the current OAM connection is correct; on the contrary, if an OAM entity does not receive the OAM connection maintenance message sent by the peer before the local OAM connection timeout timer expires, the current OAM connection is interrupted.

Commonly, for the near-end DTE and the far-end DTE that have established an OAM connection, the near-end OAM entity can send a remote loopback test command to the remote OAM entity to start the data connection between the near-end DTE and the remote DTE. Remote loopback testing of the link layer. Among them, the near-end DTE that sends the remote loopback test command is often called the loopback control end, and the remote DTE that receives the remote loopback test command is often called the loopback controlled end.

The OAM remote loopback test usually includes three stages: the loopback test startup stage, the loopback test stage and the loopback test shutdown stage. In these three stages, the near-end DTE and the far-end DTE are in different sending states and parsing states respectively. .

Before the loopback test is started, both the near-end DTE and the far-end DTE are in the non-loopback state, that is, the sending state and the parsing state are both forwarding (FWD) states, and the sending state is in FWD, which means that both control packets and Forwarding data packets, if the parsing status is FWD, it means that both control packets and data packets can be parsed, and the control packets mentioned here include OAMPDU packets.

The task of the start-up phase of the loopback test is to make the near-end DTE and the far-end DTE enter the loopback state respectively, that is: make the near-end DTE enter the loopback state and become the loopback control terminal in the loopback test, that is, the sending state is FWD , the resolution state is discarded (DC); make the remote DTE enter the loopback state and become the loopback controlled end in the loopback test, that is, the sending state is DC, and the resolution state is loopback (LB). The sending state is in DC, which means that only control packets are sent, and the data packets to be forwarded are discarded; the parsing state is in DC, which means that only the received control packets are parsed, and the received data packets are discarded; the parsing state is in LB Indicates that only the OAMPDU message is parsed, and other received messages are returned according to the original path. The other messages mentioned here include data messages and non-OAMPDU control messages.

The task of the closing stage of the loopback test is to restore the near-end DTE and the far-end DTE from the loopback state to the non-loopback state respectively, that is to say, to restore the sending state and the parsing state of the near-end DTE and the far-end DTE to FWD.

Figure 1 is a flowchart of the OAM remote loopback test specified in the current protocol, which includes the loopback test startup phase, the loopback test phase, and the loopback test shutdown phase. While performing these three phases in sequence, the near-end OAM entity and The remote OAM entity periodically sends an OAM connection maintenance message to the peer OAM entity, so as to maintain the OAM connection between the near-end DTE and the remote DTE. Among them, the OAM loopback test startup process stipulated in the current agreement includes:

Steps 101-105: After the near-end OAM entity receives the external start OAM loopback test command, it stops forwarding data packets, and sets the sending status and resolution status of the local DTE to DC; the near-end OAM entity sends a loopback test start report. Send the message LB_ON_OAMPDU_L to the remote OAM entity; after receiving LB_ON_OAMPDU_L, the remote OAM entity sets the sending status of the local DTE to DC, and sets the parsing status of the local DTE to LB; the remote OAM entity sends a loopback test start response message LB_ON_OAMPDU_R To the near-end OAM entity; after receiving the LB_ON_OAMPDU_R, the near-end OAM entity sets the sending status of the local DTE to FWD and enters the loopback test phase.

The OAM loopback test process stipulated in the current agreement includes:

Steps 106-108: the near-end OAM entity sends the loopback test data packet L to the remote OAM entity; the remote OAM entity returns the loopback test data packet L to the near-end OAM entity; the near-end OAM entity The test data packet L is returned to determine the link state.

The OAM loopback test shutdown process stipulated in the current agreement includes:

Steps 109-113: After the near-end OAM entity receives the external command to close the OAM loopback test, it stops forwarding data packets, and sets the sending status and resolution status of the local DTE to DC; the near-end OAM entity sends a loopback test shutdown report. Send the message LB_OFF_OAMPDU_L to the remote OAM entity; after receiving the LB_OFF_OAMPDU_L, the remote OAM entity sets the sending status and resolution status of the local DTE to FWD; the remote OAM entity sends the loopback test shutdown response message LB_OFF_OAMPDU_R to the near-end OAM entity; After receiving the LB_OFF_OAMPDU_R, the near-end OAM entity sets the sending status and parsing status of the local DTE to FWD, and ends this process.

While sequentially executing the loopback test startup phase, loopback test phase, and loopback test shutdown phase, the near-end OAM entity and the remote OAM entity periodically execute steps a1~b1 and steps c1~d1. The backtest phase shows steps a1-b1 and steps c1-d1.

Steps a1-b1: The near-end OAM entity periodically sends an OAM connection maintenance message INFO_OAMPDU_L to the remote OAM entity; after receiving the INFO_OAMPDU_L, the remote OAM entity resets the OAM connection timeout timer of the local DTE.

Steps c1-d1: The remote OAM entity periodically sends an OAM connection maintenance message INFO_OAMPDU_R to the local OAM entity; after receiving the INFO_OAMPDU_R, the local OAM entity resets the OAM connection timeout timer of the local DTE.

It can be seen that according to the OAM remote loopback test method stipulated in the current protocol, after entering the loopback state, the loopback control terminal and the loopback controlled terminal should send and receive OAMPDU messages as usual, and at the same time, the loopback control terminal sends to the loopback All other messages except OAMPDU from the controlled end will be returned to the loopback control end intact.

From the above analysis, we can see that the requirements of the protocol for the loopback control terminal are:

1) After entering the loopback state, it can send control packets and forward data packets;

2) After entering the loopback state, the received OAMPDU message can be parsed, and other messages except the OAMPDU message can be discarded.

The requirements of the protocol for the loopback controlled end are:

1) After entering the loopback state, it can send OAMPDU messages;

2) After entering the loopback state, it can parse the OAMPDU message and return other messages except the OAMPDU message.

In practical applications, the current DTE equipment can usually meet the requirements of the loopback control terminal stipulated in the protocol. However, limited by the function of the physical chip, the actual execution situation of the current DTE device as the loopback controlled end is usually: it can parse the OAMPDU message and return all messages including the OAMPDU message at the same time, but cannot send any message arts. Obviously, the existing DTE cannot achieve the function of looping back the controlled end stipulated in the protocol. In practical applications, if the existing DTE is used as the loopback controlled end and the OAM remote loopback test is performed according to the procedures stipulated in the protocol, the following problems will occur:

1) The protocol requires the loopback controlled terminal to enter the loopback state and send a loopback test start response message through the loopback control terminal. The loopback control terminal can change its state according to the message and enter the loopback state. However, as a loopback After the existing DTE device at the controlled end enters the loopback state, it will not be able to send any messages, including the loopback test start response message, which will prevent the loopback control end from entering the loopback state, resulting in the failure of the remote loopback test ;

2) The premise that the loopback control terminal and the loopback controlled terminal can perform the loopback test is to maintain the OAM connection between the two, that is, the two periodically send OAM connection maintenance messages to each other, so that the opposite OAM entity Reset the OAM connection timeout timer at the local end. However, after the existing DTE device as the loopback controlled end enters the loopback state, it will no longer be able to send the OAM connection maintenance message, which will make the loopback control end unable to receive it for a long time. The OAM connection keeps the packet, causing the OAM connection to time out, and the remote loopback test fails.

Contents of the invention

In view of this, the purpose of the present invention is to provide a loopback test method, which can realize the OAM remote loopback test of the existing DTE equipment.

In order to achieve the above object, the present invention provides a loopback test method, which is applicable to the near-end data terminal equipment DTE and the far-end DTE for establishing OAM connections, and the loopback test method comprises steps:

A1. The near-end DTE sends the loopback test start OAM protocol message OAMPDU to notify the remote DTE to start the loopback test, and the remote DTE enters the loopback state;

A2. The near-end DTE sends an OAMPDU as an OAM connection maintenance message to the remote DTE. By retrieving the OAMPDU returned by the remote DTE as an OAM connection maintenance message, it is confirmed that the remote DTE enters the loopback state, and the local DTE enters the loopback state. return status;

A3. The near-end DTE sends a loopback test data packet to the remote DTE, and determines the link status by retrieving the loopback test data packet returned by the remote DTE.

Wherein, the loopback state of the near-end DTE is to send control messages and forward data messages to the far-end DTE, only parse the OAMPDU from the far-end DTE and discard other messages from the far-end DTE.

Wherein, the loopback state of the remote DTE is that no message is sent, only the OAMPDU from the near-end DTE is parsed and all messages from the near-end DTE are returned to the near-end DTE.

Wherein, before the far-end DTE enters the loopback state, the OAM connection maintenance process between the near-end DTE and the far-end DTE includes:

The local DTE periodically sends an OAMPDU as an OAM connection maintenance message to the remote DTE, and the remote DTE resets the local OAM connection timeout timer.

The remote DTE periodically sends an OAMPDU as an OAM connection maintenance message to the local DTE, and the local DTE resets the local OAM connection timeout timer.

Wherein, after the near-end DTE enters the loopback state, the OAM connection maintenance process between the near-end DTE and the far-end DTE includes:

B1. The near-end DTE periodically sends the OAMPDU as an OAM connection maintenance message to the remote DTE, and the remote DTE resets the local OAM connection timeout timer, and returns the received OAMPDU as an OAM connection maintenance message to the near-end DTE;

B2. The near-end DTE reclaims the OAMPDU returned by the far-end DTE as an OAM connection maintenance message, and resets the OAM connection timeout timer of the local DTE.

Wherein, after the step A3, further include:

A4. The near-end DTE sends a loopback test close OAMPDU to notify the remote DTE to end the loopback test, and the remote DTE ends the loopback state;

A5. The remote DTE sends a loopback test close response OAMPDU to the local DTE, and the local DTE ends the loopback state.

Wherein, before the far-end DTE ends the loopback state, the OAM connection maintenance process between the near-end DTE and the far-end DTE includes:

C1. The local DTE periodically sends the OAMPDU as an OAM connection maintenance message to the remote DTE. The remote DTE resets the local OAM connection timeout timer and returns the received OAMPDU as an OAM connection maintenance message to the local DTE. ;

C2. The local DTE reclaims the OAMPDU returned by the remote DTE as an OAM connection maintenance message, and resets the OAM connection timeout timer of the local DTE.

Wherein, after the far-end DTE ends the loopback state, the OAM connection maintenance process between the near-end DTE and the far-end DTE includes:

The local DTE periodically sends an OAMPDU as an OAM connection maintenance message to the remote DTE, and the remote DTE resets the local OAM connection timeout timer.

The remote DTE periodically sends an OAMPDU as an OAM connection maintenance message to the local DTE, and the local DTE resets the local OAM connection timeout timer.

It can be seen that the OAM remote loopback test method provided by the present invention, according to the function of the existing DTE equipment, utilizes this characteristic of returning all messages after the existing DTE equipment as the loopback controlled end enters the loopback state, controlled by the loopback The terminal recycles the OAM connection keeping message sent by itself to know whether the other party enters the loopback state and whether the current OAM connection is correct. This method can perform a remote loopback test on the existing DTE device.

Description of drawings

Figure 1 is a flowchart of the OAM remote loopback test specified in the current protocol.

Fig. 2 is a flow chart of the OAM remote loopback test of the present invention.

Detailed ways

The core idea of the present invention is: aiming at the feature that the existing DTE equipment will return all messages when it is used as the loopback controlled terminal, the loopback control terminal can know the loopback controlled terminal by reclaiming the OAM connection maintenance message sent by itself. Enter the loopback state, and maintain the OAM connection between itself and the loopback controlled end.

In order to make the object, technical solution and advantages of the present invention clearer, the following examples are given and the present invention is further described in detail with reference to the accompanying drawings.

FIG. 2 is a flow chart of the OAM remote loopback test of the present invention, which includes a loopback test startup phase, a loopback test phase, and a loopback test shutdown phase. Among them, the near-end DTE as the loopback control terminal satisfies the requirements of the protocol for the loopback control terminal, and the remote DTE as the loopback controlled terminal enters the loopback state. After entering the loopback state, the sending state is DC′, the parsing state is LB′, and the sending state is DC' indicates that no message can be sent, and the parsing status of LB' means parsing the OAMPDU message and returning all messages including the OAMPDU message.

The loopback test startup procedure of the present invention comprises:

Steps 201 to 203: After the near-end OAM entity receives the external start OAM loopback test command, it stops forwarding data packets, and sets the sending status and resolution status of the local DTE as DC; the near-end OAM entity sends a loopback test start report Send the message LB_ON_OAMPDU_L to the remote OAM entity; after receiving LB_ON_OAMPDU_L, the remote OAM entity sets the sending state of the local DTE to DC', sets the parsing state of the local DTE to LB', and the remote DTE enters the loopback state.

While executing steps 201 to 203, the near-end OAM entity and the remote OAM entity periodically send OAM connection maintenance messages to the peer OAM entity, thereby maintaining the OAM connection between the near-end DTE and the far-end DTE, as shown in Fig. The specific situation is not shown in 2. For detailed steps, refer to steps a1-b1 and steps c1-d1 in FIG. 1, which will not be described in detail here.

Steps 204-207: The near-end OAM entity sends an OAM connection maintenance message INFO_OAMPDU_L to the remote OAM entity; after receiving the INFO_OAMPDU_L, the remote OAM entity resets the local OAM connection timeout timer; the remote OAM entity returns INFO_OAMPDU_L to the near-end OAM Entity: After the near-end OAM entity reclaims the INFO_OAMPDU_L, it resets the local OAM connection timeout timer, and sets the parsing state of the local DTE to FWD.

Wherein, the OAM connection maintenance message INFO_OAMPDU_L that the near-end OAM entity sends to the remote OAM entity in step 204 is the first OAM connection maintenance message received after the remote DTE enters the loopback state. After the remote OAM entity receives the OAM connection keeping message, it will reset the OAM connection timer of the local DTE, and return the received OAM connection keeping message to the near-end OAM entity.

Similarly, the OAM connection maintenance message INFO_OAMPDU_L returned by the remote DTE to the local DTE in step 206 is the first OAM connection maintenance message whose MAC address is itself received by the local DTE. The remote DTE can know from the message that the remote DTE has entered the loopback state. After receiving the OAM connection maintenance message, the remote DTE can reset the OAM connection timeout timer of the local DTE and set the local end to send The state is FWD, and the near-end DTE enters the loopback state.

OAM loopback test process of the present invention comprises:

Steps 207-209: The near-end OAM entity sends the loopback test data packet L to the remote OAM entity; the remote OAM entity returns the loopback test data packet L to the near-end OAM entity; the near-end OAM entity The test data packet L is returned to determine the link state.

OAM loopback test closing process of the present invention comprises:

Steps 210 to 214: After the near-end OAM entity receives the external command to close the OAM loopback test, it stops forwarding data packets, and sets the sending status and resolution status of the local DTE to DC; the near-end OAM entity sends a loopback test shutdown report. Send the message LB_OFF_OAMPDU_L to the remote OAM entity; after receiving the LB_OFF_OAMPDU_L, the remote OAM entity sets the sending status and resolution status of the local DTE to FWD; the remote OAM entity sends the loopback test shutdown response message LB_OFF_OAMPDU_R to the near-end OAM entity; After receiving the LB_OFF_OAMPDU_R, the near-end OAM entity sets the sending and parsing status of the local DTE to FWD, and ends this process.

While executing steps 207-212, the near-end OAM entity and the far-end OAM entity periodically execute steps a2-d2.

Steps a2-d2: The near-end OAM entity sends an OAM connection maintenance message INFO_OAMPDU_L to the remote OAM entity; after receiving the INFO_OAMPDU_L, the remote OAM entity resets the OAM connection timeout timer of the local DTE; the remote OAM entity returns INFO_OAMPDU_L to the near-end OAM entity The terminal OAM entity; after the near-end OAM entity reclaims the INFO_OAMPDU_L, it resets the OAM connection timeout timer of the local DTE.

While executing steps 213-214, the near-end OAM entity and the remote OAM entity periodically send OAM connection maintenance messages to the peer OAM entity, thereby maintaining the OAM connection between the near-end DTE and the far-end DTE, as shown in Fig. The specific situation is not shown in 2. For detailed steps, refer to steps a1-b1 and steps c1-d1 in FIG. 1, which will not be described in detail here.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention.

Claims (8)

1. a loopback test method, be applicable to the near-end data terminal equipment DTE and the far-end DTE that establish OAM connection, it is characterized in that, described loopback test method comprises steps: A1. The near-end DTE sends the loopback test start OAM protocol message OAMPDU to notify the remote DTE to start the loopback test, and the remote DTE enters the loopback state; A2. The near-end DTE sends an OAMPDU as an OAM connection maintenance message to the remote DTE. By retrieving the OAMPDU returned by the remote DTE as an OAM connection maintenance message, it is confirmed that the remote DTE enters the loopback state, and the local DTE enters the loopback state. return status; A3. The near-end DTE sends a loopback test data packet to the remote DTE, and determines the link status by retrieving the loopback test data packet returned by the remote DTE. 2. The method according to claim 1, wherein the loopback state of the near-end DTE is to send control packets and forward data packets to the far-end DTE, only resolve the OAMPDU from the far-end DTE and discard Other messages from the remote DTE. 3. method as claimed in claim 1, is characterized in that, the loopback state of described far-end DTE is, does not send message, only resolves the OAMPDU from near-end DTE and returns all messages from near-end DTE to Proximal DTE. 4. The method according to claim 1, wherein before the far-end DTE enters the loopback state, the OAM connection maintenance process between the near-end DTE and the far-end DTE comprises: The local DTE periodically sends an OAMPDU as an OAM connection maintenance message to the remote DTE, and the remote DTE resets the local OAM connection timeout timer. The remote DTE periodically sends an OAMPDU as an OAM connection maintenance message to the local DTE, and the local DTE resets the local OAM connection timeout timer. 5. The method according to claim 1, wherein after the near-end DTE enters the loopback state, the OAM connection maintenance process between the near-end DTE and the far-end DTE comprises: B1. The near-end DTE periodically sends the OAMPDU as an OAM connection maintenance message to the remote DTE, and the remote DTE resets the local OAM connection timeout timer, and returns the received OAMPDU as an OAM connection maintenance message to the near-end DTE; B2. The near-end DTE reclaims the OAMPDU returned by the far-end DTE as an OAM connection maintenance message, and resets the OAM connection timeout timer of the local DTE. 6. The method according to claim 1, further comprising after the step A3: A4. The near-end DTE sends a loopback test close OAMPDU to notify the remote DTE to end the loopback test, and the remote DTE ends the loopback state; A5. The remote DTE sends a loopback test close response OAMPDU to the local DTE, and the local DTE ends the loopback state. 7. The method according to claim 6, wherein the OAM connection maintenance process between the near-end DTE and the far-end DTE includes: C1. The local DTE periodically sends the OAMPDU as an OAM connection maintenance message to the remote DTE. The remote DTE resets the local OAM connection timeout timer and returns the received OAMPDU as an OAM connection maintenance message to the local DTE. ; C2. The local DTE reclaims the OAMPDU returned by the remote DTE as an OAM connection maintenance message, and resets the OAM connection timeout timer of the local DTE. 8. The method according to claim 6, wherein after the far-end DTE ends the loopback state, the OAM connection maintenance process between the near-end DTE and the far-end DTE includes: The local DTE periodically sends an OAMPDU as an OAM connection maintenance message to the remote DTE, and the remote DTE resets the local OAM connection timeout timer. The remote DTE periodically sends an OAMPDU as an OAM connection maintenance message to the local DTE, and the local DTE resets the local OAM connection timeout timer.

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