Method and device for reducing CCM message flow of point-to-point physical link level

Abstract

The invention discloses a method and device for reducing CCM message flow of a point-to-point physical link hierarchy, and the method comprises the steps: S1, recording the lastsendtime of the latest sending of an Ethernet frame on each port and a mark of whether the frame is sent or not in a sending direction; s2, the MEP CC generator state machine generates a CCM message according to the configuration period of the CCM, circularly enters a CCIWAITING state, and when a CCM sending timer CCIwhite is overtime, the CCIwhite is updated according to the hadse and the lastsendtime recorded on the port, and the CCIWAITING state is maintained; s3, in the receiving direction, recording the lastreceived time when the Ethernet frame is received recently on each port and a hadreceived mark of whether the frame is received or not; and S4, the RMEP state machine decides whether the CFM instance gives an alarm or not and modifies the REMPOK state, and when the CCM timeout timer rMEPwhite is timeout, the rMEPwhite is updated according to the haded time and the lastreceived time recorded on the port, and the REMPOK state is maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of connection fault management (CFM), and in particular to a method and device for reducing CCM message traffic at a point-to-point physical link layer. Background Art

[0002] IEEE 802.1ag, also known as Connectivity Fault Management (CFM), is a network management protocol designed to provide connectivity fault management capabilities in Ethernet networks, specifically for maintaining and monitoring the continuity and performance of Ethernet networks. ITU-T Y.1731 is a standard developed by the International Telecommunication Union (ITU-T) that provides a set of detailed specifications for Operation and Maintenance Management (OAM) of Ethernet networks. Designed to ensure the reliability and performance of the network, it is similar to the IEEE 802.1ag standard. In both standards, connectivity check capabilities based on the Connectivity Check Message (CCM) are defined.

[0003] CFM OAM sends CCMs continuously at a high frequency through the sender. If the receiver does not receive CCMs for several consecutive times, it will determine that the connection with the sender is disconnected. The maximum CCM transmission frequency defined in the standard is 300Hz. According to the minimum Ethernet message length of 64 bytes, the CCM traffic between two OAM maintenance endpoints is greater than 400Kbps.

[0004] The traffic of CCM messages occupies the network bandwidth. When the network service is congested, in order to ensure the normal operation of the OAM connection fault management function, high priority services will be provided to CCM messages, thereby squeezing out network services and causing the actual network service capacity to decline. In addition, high-frequency CCM processing will also occupy processor capacity and increase system power consumption. Summary of the invention

[0005] The present invention provides a technology for reducing the sending of CCM for CFM of a physical link, more specifically, a CCM sending and receiving method based on IEEE802.1ag and ITU-T Y.1731 standards, which reduces the CCM messages of CFM at the physical link level, thereby reducing the OAM message traffic, improving the business service capability of the Ethernet link, reducing the load of the OAM processor, and reducing the false alarm of CFM alarm at the physical link level.

[0006] In order to achieve the above object, the technical solution of the present invention provides a method for reducing the CCM message traffic at the point-to-point physical link layer, which includes: S1: in the sending direction, recording the time last_send_time of the most recently sent Ethernet frame on each port and the mark had_sent of whether the frame has been sent; S2: MEP The CC generator state machine generates CCM messages according to the configuration cycle of CCM, and circulates into the CCI_WAITING state. When the CCM sending timer CCIwhile times out, CCIwhile is updated according to had_sent and last_send_time recorded on the port, and the CCI_WAITING state is maintained; S3: In the receiving direction, the time last_receive_time of the most recent Ethernet frame received on each port and the had_received mark indicating whether a frame has been received are recorded; S4: The RMEP state machine decides whether the CFM instance issues an alarm and modifies the REMP_OK state. When the CCM timeout timer rMEPwhile times out, rMEPwhile is updated according to had_received and last_receive_time recorded on the port, and the REMP_OK state is maintained.

[0007] Furthermore, in step S1, the time of the most recent Ethernet frame sent on each port is recorded. After each Ethernet frame is sent, the frame sending time last_send_time on the port is updated, and the sending flag had_sent is set to true; and in step S3, the time of the most recent Ethernet frame received on each port is recorded. After each Ethernet frame is received, the frame receiving time last_receive_time on the port is updated, and had_received is set to true.

[0008] Further, in step S2, the MEP CC generator state machine periodically starts to generate CCM and loops into the CCI_WAITING state, wherein, for the CFM at the physical link level, in the CCI_WAITING state, when CCIwhile times out, the frame sending flag had_sent of the corresponding port is judged, and if had_sent=true, the time of CCIwhile is reset based on last_send_time, and then had_sent is set to false; otherwise, the corresponding operation is performed in accordance with the CFM OAM standard.

[0009] Further, in step S2, the time of CCIwhile is reset using the difference between last_send_time and the current time NOW, and the reset value is CCMinterval-(NOW-last_send_time), where CCMinterval is the CCM sending interval.

[0010] Further, in step S4, the RMEP state machine determines whether CCM has been received within the life cycle of CCM. If not, it enters the RMEP_FAILED state, otherwise it maintains the REMP_OK state, and the CCM life cycle = 3.5*CCMinterval; wherein, for the physical link level CFM, in the REMP_OK state, when rMEPwhile times out, the frame reception flag had_received of the corresponding port is determined, and if had_received = true, the time of rMEPwhile is reset based on last_receive_time, and then had_received is set to false; otherwise, the corresponding operation is performed in accordance with the CFM OAM standard.

[0011] Furthermore, in step S4, the time of rMEPwhile is reset using the difference between last_receive_time and the current time NOW, and the reset value is 3.5*CCMinterval-(NOW-last_receive_time).

[0012] The technical solution of the present invention also provides a device for reducing the CCM message flow at the point-to-point physical link level, which includes: a link sending record module, which is used to record the time last_send_time of each port's most recent Ethernet frame sending and the mark had_sent of whether the frame has been sent; a MEP The CCI_WAITING state processing module of the CC generator state machine is used to generate CCM messages according to the configuration period of CCM, modify the CCI_WAITING state, and when the CCM sending timer CCIwhile times out, update CCIwhile according to had_sent and last_send_time recorded on the port to maintain the CCI_WAITING state; the link reception recording module is used to record the time last_receive_time when each port most recently received the Ethernet frame and the had_received mark whether the frame has been received; the RMEP_OK state module of the RMEP state machine is used to decide whether the CFM instance issues an alarm, modify the REMP_OK state, and when the CCM timeout timer rMEPwhile times out, update rMEPwhile according to had_received and last_receive_time recorded on the port to maintain the REMP_OK state.

[0013] The technical solution of the present invention also provides a method for reducing the CCM message traffic at the point-to-point physical link layer, which includes: S1: in the sending direction, the MEP CC generator state machine generates a CCM message according to the configuration period of the CCM, modifies the CCI_WAITING state, and when the CCM sending timer CCIwhile times out, generates a mark had_sent indicating whether an Ethernet frame has been sent recently according to the statistical information of the management information base MIB on the port, and when had_sent=true, resets CCIwhile and maintains the CCI_WAITING state; S2: in the receiving direction, the RMEP state machine decides whether the CFM instance issues an alarm, modifies the REMP_OK state, and when the CCM timeout timer rMEPwhile times out, the RMEP state machine generates a mark had_received indicating whether an Ethernet frame has been received recently according to the statistical information of the management information base MIB of the port, and when had_received=true, resets rMEPwhile and maintains the REMP_OK state.

[0014] The technical solution of the present invention also provides a method for improving the robustness of point-to-point physical link level CFM, which includes: S3: in the receiving direction, recording the time last_receive_time when each port most recently received the Ethernet frame and the mark had_received of whether the frame has been received; S4: the RMEP state machine decides whether the CFM instance issues an alarm and modifies the REMP_OK state. When the CCM timeout timer rMEPwhile times out, rMEPwhile is updated according to had_received and last_receive_time recorded on the port to maintain the REMP_OK state. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 It is a schematic diagram of the processing flow of the link sending record module of the present invention;

[0017] Figure 2 is a schematic diagram of the processing flow of the modified MEP CC generator state machine of the present invention;

[0018] Figure 3 is a schematic diagram of the processing flow of the link reception recording module of the present invention;

[0019] Figure 4 It is a schematic diagram of the processing flow of the modified RMEP state machine of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] CFM OAM allows the other end to perceive the network connectivity by continuously sending CCMs. The frequency of sending CCMs is usually very high, and two maintenance-associated endpoints must use up to 400Kbps of traffic to send CCMs. On a point-to-point physical link, in fact, it is only necessary to determine whether the link is connected based on whether the port receives an Ethernet frame.

[0022] When the link service is congested, CCM either occupies service bandwidth, affecting user experience, or discards CCM, triggering a CFM alarm.

[0023] The MEP Continuity Check Initiator state machine is a state machine for the MEP instance to generate CCM messages. After the MEP is enabled, it will enter the CCI_WAITING state and enter it cyclically. When entering the CCI_WAITING state, it sends a CCM message and waits for the CCMinterval (CCM transmission interval, CCMinterval-The configured time between CCM transmissions). This state machine sends a CCM message every CCMinterval. The RMEP state machine is a state machine for the MEP to determine whether the peer end is faulty based on the CCM sent by the receiving peer end. Each time a CCM message is received, it will enter the RMEP_OK state and then wait for 3.5 CCMintervals. If no CCM message is received during this period, it is determined that the peer end is faulty and enters the RMEP_FAILED state. If a CCM is received, it is determined to be normal and will repeatedly enter the RMEP_OK state.

[0024] The CFM technology at the physical link layer of the present invention records the time when the most recent frame is sent and received on the port, and modifies the MEP (Maintenance association End Point) CC (Continuity Check) generator state machine and the RMEP (Remote MEP) state machine of the point-to-point physical link, and uses the time of the most recent frame reception and transmission in the state machine. The CCI_WAITING state is modified in the MEP CC generator state machine to reduce the chance of repeatedly entering the CCI_WAITING state to reduce the generation of CCM. The RMEP_OK state is modified in the RMEP state machine to maintain the REMP_OK state to reduce the chance of entering the REMP_FAILED state, thereby reducing the triggering of CCM alarms.

[0025] In the sending direction, it includes a link sending record module and a modified MEP CC generator state machine. The link sending record module is used to record the time last_send_time when the most recent Ethernet frame was sent by each port and the mark had_sent whether it has been sent. The modified MEP CC generator state machine, based on the MEP CC generator of the IEEE 802.1ag standard, is used to generate CCM messages according to the configuration period of CCM, modify the CCI_WAITING state, and update CCIwhile according to had_sent and last_send_time recorded on the port when the CCIwhile timer times out, and maintain the CCI_WAITING state.

[0026] In the receiving direction, it includes a link receiving record module and a modified RMEP state machine. The link receiving record module is used to record the time last_receive_time when each port recently received an Ethernet frame and the mark last_received whether a frame has been received. The modified RMEP state machine, based on the IEEE 802.1ag standard RMEP state machine, is used to decide whether the CFM instance issues an alarm and modify the REMP_OK state. When the rMEPwhile timer times out, the rMEPwhile is updated according to the had_received and last_receive_time recorded on the port to maintain the REMP_OK state.

[0027] See also Figure 1-Figure 4 The method of reducing the OAM continuity detection message traffic at the physical link layer of the present invention mainly includes the following modules:

[0028] (1) Link sending record module, records the time of the last Ethernet frame sent on each port. After each Ethernet frame is sent, the frame sending time last_send_time on the port is updated and the sending flag had_sent is set to true.

[0029] (2) The CCI_WAITING state processing module of the MEP CC generator state machine periodically starts generating CCMs based on the IEEE802.1ag and Y.1731 standards. For the CFM at the physical link level, the frame transmission flag had_sent of the corresponding port is determined. When the CCM transmission timer CCIwhile (Timer counter for transmitting CCMs) times out, the time of CCIwhile is reset using the difference between the time last_send_time of the last transmitted frame and the current time NOW. The reset value is CCMinterval-(NOW-last_send_time), and then had_sent is set to false. That is, when the timer CCIwhile times out, if an Ethernet frame has been sent within the CCMinterval, that is, had_sent = true, the CCI_WAITING state is maintained, so there is no need to send CCMs, and the timer is reset. Otherwise, CCMs continue to be sent according to the CFM OAM standard.

[0030] (3) Link receiving record module, which records the time of the last Ethernet frame received on each port. After each Ethernet frame is received, the frame receiving time last_receive_time on the port is updated and had_received is set to true.

[0031] (4) The RMEP_OK state module of the RMEP state machine, based on the IEEE802.1ag and Y.1731 standards, determines whether a CCM has been received within the CCM life cycle (3.5*CCMinterval). If not, it enters the RMEP_FAILED state. For the physical link-level CFM, the frame reception flag had_received of the corresponding port is determined. If had_received = true, when the rMEPwhile timer times out, the difference between the time last_receive_time of the most recently received frame and the current time NOW is used to reset the rMEPwhile time. The reset value is 3.5*CCMinterval-(NOW-last_receive_time), and then had_received is set to false. That is, when the timer rMEPwhile timer times out, if an Ethernet frame has been received within the CCM life cycle, the RMEP_OK state is maintained and the timer is reset. Otherwise, it follows the CFM OAM standard to enter the RMEP_FAILED state and considers the peer to be faulty.

[0032] (5) Other modules of the MEP CC state machine and the RMEP state machine comply with the IEEE802.1ag and Y.1731 standards.

[0033] The functions in modules (1), (2), (3), (4), and (5) can be implemented separately or in combination. Modules (3) and (4) in the receiving direction can be implemented independently, which can reduce the false alarm rate of physical link-level CFM alarm decisions. Modules (1) and (2) in the sending direction depend on modules (3) and (4) at the receiving end and need to be supported by both ends to be used.

[0034] The above technical solution of the present invention is to use the Ethernet frame transmitted on the link as a supplement to the alarm decision of the point-to-point physical link level CFM. The alarm decision of CFM specified in the standard is based on the CCM sending frequency. For example, if a CCM is sent once every 3.33 milliseconds and no CCM is received from the other end within 3.5 sending cycles, it is determined that the connection fails. In actual implementation, it may be periodically recorded whether there is an Ethernet frame sent or received in each time slice, and a better algorithm and access performance can be obtained by recording a flag parameter instead of time.

[0035] Alternatively, in the RMEP state machine, for point-to-point physical link level CFM, whether an Ethernet frame is received during the CCM life cycle can also be judged based on the MIB (Management Information Base) statistical information of the port, without having to record the time or mark information each time an Ethernet frame is received.

[0036] In addition, the use of the method of the present invention by the transmitting end depends on the receiving end also supporting the method of the present invention, but the receiving end can independently implement the method of the present invention, and does not depend on whether the transmitting end supports the method of the present invention. When the transmitting end does not implement the method of the present invention, the receiving end uses the method of the present invention to improve the robustness of the point-to-point physical link level CFM and reduce the probability of CFM alarm false alarms.

[0037] In an embodiment of the present invention, a method for reducing CCM message traffic at a point-to-point physical link layer is provided, which includes: S1: in the sending direction, recording the time last_send_time of the most recent Ethernet frame sent on each port and the mark had_sent whether the frame has been sent; S2: the MEP CC generator state machine generates CCM messages according to the configuration period of CCM, and cyclically enters the CCI_WAITING state. When the CCM sending timer CCIwhile times out, CCIwhile is updated according to had_sent and last_send_time recorded on the port, and the CCI_WAITING state is maintained; S3: in the receiving direction, recording the time last_receive_time of the most recent Ethernet frame received on each port and the mark had_received whether the frame has been received; S4: the RMEP state machine decides whether the CFM instance issues an alarm, modifies the REMP_OK state, and when the CCM timeout timer rMEPwhile times out, rMEPwhile is updated according to had_received and last_receive_time recorded on the port, and the REMP_OK state is maintained.

[0038] Furthermore, in step S1, the time of the most recent Ethernet frame sent on each port is recorded. After each Ethernet frame is sent, the frame sending time last_send_time on the port is updated, and the sending flag had_sent is set to true; and in step S3, the time of the most recent Ethernet frame received on each port is recorded. After each Ethernet frame is received, the frame receiving time last_receive_time on the port is updated, and had_received is set to true.

[0039] Further, in step S2, the MEP CC generator state machine periodically starts to generate CCM and loops into the CCI_WAITING state, wherein, for the CFM at the physical link level, in the CCI_WAITING state, when CCIwhile times out, the frame sending flag had_sent of the corresponding port is judged, and if had_sent=true, the time of CCIwhile is reset based on last_send_time, and then had_sent is set to false; otherwise, the corresponding operation is performed in accordance with the CFM OAM standard.

[0040] Further, in step S2, the time of CCIwhile is reset using the difference between last_send_time and the current time NOW, and the reset value is CCMinterval-(NOW-last_send_time), where CCMinterval is the CCM sending interval.

[0041] Further, in step S4, the RMEP state machine determines whether CCM has been received within the life cycle of CCM. If not, it enters the RMEP_FAILED state, otherwise it maintains the REMP_OK state, and the CCM life cycle = 3.5*CCMinterval; wherein, for the physical link level CFM, in the REMP_OK state, when rMEPwhile times out, the frame reception flag had_received of the corresponding port is determined, and if had_received = true, the time of rMEPwhile is reset based on last_receive_time, and then had_received is set to false; otherwise, the corresponding operation is performed in accordance with the CFM OAM standard.

[0042] Further, in step S4, the time of rMEPwhile is reset using the difference between last_receive_time and the current time NOW, and the reset value is 3.5*CCMinterval-(NOW-last_receive_time).

[0043] In another embodiment of the present invention, a device for reducing the CCM message flow at the point-to-point physical link layer is also provided, which includes: a link sending record module, used to record the time last_send_time of the most recent Ethernet frame sent by each port and the mark had_sent of whether the frame has been sent; MEP The CCI_WAITING state processing module of the CC generator state machine is used to generate CCM messages according to the configuration period of CCM, modify the CCI_WAITING state, and when the CCM sending timer CCIwhile times out, update CCIwhile according to had_sent and last_send_time recorded on the port to maintain the CCI_WAITING state; the link reception recording module is used to record the time last_receive_time when each port most recently received the Ethernet frame and the had_received mark whether the frame has been received; the RMEP_OK state module of the RMEP state machine is used to decide whether the CFM instance issues an alarm, modify the REMP_OK state, and when the CCM timeout timer rMEPwhile times out, update rMEPwhile according to had_received and last_receive_time recorded on the port to maintain the REMP_OK state.

[0044] In another embodiment of the present invention, a method for reducing the CCM message traffic at the point-to-point physical link layer is also provided, which includes: S1: in the sending direction, the MEP CC generator state machine generates a CCM message according to the configuration period of the CCM, modifies the CCI_WAITING state, and when the CCM sending timer CCIwhile times out, generates a mark had_sent to indicate whether an Ethernet frame has been sent recently based on the statistical information of the management information base MIB on the port, and when had_sent=true, resets CCIwhile and maintains the CCI_WAITING state; S2: in the receiving direction, the RMEP state machine decides whether the CFM instance issues an alarm, modifies the REMP_OK state, and when the CCM timeout timer rMEPwhile times out, the RMEP state machine generates a mark had_received to indicate whether an Ethernet frame has been received recently based on the statistical information of the management information base MIB of the port, and when had_received=true, resets rMEPwhile and maintains the REMP_OK state.

[0045] In other embodiments of the present invention, a method for improving the robustness of point-to-point physical link level CFM is also provided, which includes: S3: in the receiving direction, recording the time last_receive_time when each port most recently received the Ethernet frame and the mark had_received indicating whether the frame has been received; S4: the RMEP state machine decides whether the CFM instance issues an alarm and modifies the REMP_OK state. When the CCM timeout timer rMEPwhile times out, rMEPwhile is updated according to had_received and last_receive_time recorded on the port to maintain the REMP_OK state.

[0046] Beneficial technical effects of the present invention:

[0047] The present invention uses the Ethernet frame on the link to act as the CCM function of the point-to-point physical link level CFM, reducing the traffic of the CCM on the link. When the link is congested, because there are always service frames on the link, no CCM is generated for the physical link level CFM. In this way, the function of the physical link level CFM can still be kept working normally without increasing additional traffic;

[0048] The reduction of CCMs can also reduce the load on the OAM processor and the power consumption of the overall system;

[0049] Because CCM itself is also an Ethernet frame, when deciding physical link-level CFM connectivity, judging whether the port has recently received an Ethernet frame is more accurate than judging whether the port has received a physical link-level CCM. This can reduce false alarms and achieve better results.

[0050] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for reducing CCM message traffic at a point-to-point physical link level, characterized in that: include: S1: In the sending direction, record the time last_send_time of the most recent Ethernet frame sent on each port and the mark had_sent indicating whether the frame has been sent; S2: The MEP CC generator state machine generates CCM messages according to the CCM configuration period, and cyclically enters the CCI_WAITING state. When the CCM send timer CCIwhile times out, CCIwhile is updated according to had_sent and last_send_time recorded on the port, and the CCI_WAITING state is maintained; S3: In the receiving direction, record the time last_receive_time when the Ethernet frame was most recently received on each port and the mark had_received indicating whether a frame has been received; S4: The RMEP state machine decides whether the CFM instance issues an alarm and modifies the REMP_OK state. When the CCM timeout timer rMEPwhile times out, rMEPwhile is updated according to had_received and last_receive_time recorded on the port to maintain the REMP_OK state.

2. The method according to claim 1, characterized in that In step S1, the time of the most recent Ethernet frame transmission on each port is recorded, and after each Ethernet frame transmission, the frame transmission time last_send_time on the port is updated, and the transmission flag had_sent is set to true; and In step S3, the time of the most recent Ethernet frame reception on each port is recorded. After each Ethernet frame is received, the frame reception time last_receive_time on the port is updated, and had_received is set to true.

3. The method according to claim 2, characterized in that In step S2, the MEP CC generator state machine periodically starts generating CCMs and cyclically enters the CCI_WAITING state, where: For physical link-level CFM, in the CCI_WAITING state, when CCIwhile times out, the frame sending flag had_sent of the corresponding port is determined. If had_sent = true, the time of CCIwhile is reset based on last_send_time, and then had_sent is set to false; otherwise, the corresponding operation is performed in accordance with the CFM OAM standard.

4. The method according to claim 3, characterized in that: In step S2, the time of CCIwhile is reset using the difference between last_send_time and the current time NOW, and the reset value is CCMinterval-(NOW-last_send_time), where CCMinterval is the CCM sending interval.

5. The method according to claim 3, characterized in that: In step S4, the RMEP state machine determines whether a CCM has been received within the CCM life cycle. If not, it enters the RMEP_FAILED state, otherwise it maintains the REMP_OK state. The CCM life cycle = 3.5*CCMinterval; where, For physical link level CFM, in the REMP_OK state, when rMEPwhile times out, the frame reception flag had_received of the corresponding port is determined. If had_received = true, the time of rMEPwhile is reset based on last_receive_time, and then had_received is set to false; otherwise, the corresponding operation is performed in accordance with the CFM OAM standard.

6. The method according to claim 5, characterized in that In step S4, the time of rMEPwhile is reset using the difference between last_receive_time and the current time NOW, and the reset value is 3.5*CCMinterval-(NOW-last_receive_time).

7. A device for reducing CCM message traffic at a point-to-point physical link layer, characterized in that: include: The link sending record module is used to record the time last_send_time when each port recently sent an Ethernet frame and the mark had_sent indicating whether a frame has been sent; The CCI_WAITING state processing module of the MEP CC generator state machine is used to generate CCM messages according to the configuration period of CCM, modify the CCI_WAITING state, and when the CCM send timer CCIwhile times out, update CCIwhile according to had_sent and last_send_time recorded on the port to maintain the CCI_WAITING state; The link receiving record module is used to record the time last_receive_time when each port recently received the Ethernet frame and the mark had_received indicating whether the frame has been received; The RMEP_OK state module of the RMEP state machine is used to decide whether the CFM instance issues an alarm and modify the REMP_OK state. When the CCM timeout timer rMEPwhile times out, rMEPwhile is updated according to the had_received and last_receive_time recorded on the port to maintain the REMP_OK state.

8. A method for reducing CCM message traffic at a point-to-point physical link level, characterized in that: include: S1: In the sending direction, the MEP CC generator state machine generates CCM messages according to the CCM configuration period, modifies the CCI_WAITING state, and when the CCM sending timer CCIwhile times out, it generates a mark had_sent to indicate whether an Ethernet frame has been sent recently based on the statistical information of the management information base MIB on the port. When had_sent = true, CCIwhile is reset to maintain the CCI_WAITING state; S2: In the receiving direction, the RMEP state machine decides whether the CFM instance issues an alarm and modifies the REMP_OK state. When the CCM timeout timer rMEPwhile times out, the RMEP state machine obtains the had_received flag indicating whether an Ethernet frame has been received recently based on the statistical information of the port's management information base MIB. When had_received = true, rMEPwhile is reset to maintain the REMP_OK state.

9. A method for improving the robustness of point-to-point physical link level CFM, characterized in that: include: S3: In the receiving direction, record the time last_receive_time when each port received the most recent Ethernet frame and the mark had_received indicating whether the frame has been received; S4: The RMEP state machine decides whether the CFM instance issues an alarm and modifies the REMP_OK state. When the CCM timeout timer rMEPwhile times out, rMEPwhile is updated according to had_received and last_receive_time recorded on the port to maintain the REMP_OK state.

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