WO2014008809A1

WO2014008809A1 - Frame loss detection method and system

Info

Publication number: WO2014008809A1
Application number: PCT/CN2013/077818
Authority: WO
Inventors: 吴少勇; 苏卉; 杨瑾
Original assignee: 中兴通讯股份有限公司
Priority date: 2012-07-09
Filing date: 2013-06-24
Publication date: 2014-01-16
Also published as: CN103546303A

Abstract

Provided are a frame loss detection method and system. The method includes: a first node and a second node which require frame loss detection counting the frame counts thereof respectively; the first node sending to the second node a detection message frame which contains the frame count of the first node and an identifier which can be identified by the second node; after receiving the detection message frame, the second node sending a detection response message frame which contains the frame count of the second node and an identifier which can be identified by the first node; and after receiving the detection response message frame, the first node determining a frame loss situation between the first node and the second node. By performing the interaction of a detection message frame and a detection response message frame between nodes, when a fault occurs in a network resulting in frame loss, the present invention can detect a frame loss count between one node and other nodes respectively, and when there is frame loss between two adjacent nodes, it can also be detected, which facilitates the fault location, maintenance and management of a network.

Description

Method and system for measuring lost frame

The present invention relates to the field of network communication technologies, and in particular, to a method and system for determining lost frames. Background technique

When traffic is lost in the network, it usually causes service interruption, which brings a lot of inconvenience to users. There are many technologies in the industry to quickly detect traffic loss. For example, according to the International Telecommunication Union Telecommunication Standardization Sector (ITU-T, ITU Telecommunication Standardization Sector) Y.1731, Ethernet Operation Management Maintenance (OAM) and G.8113 · 1 transmission characteristics of multi-protocol label switching ( MPLS-TP (Multi-Protocol Label Switching Transport Profile) The definition of OAM, end-to-end frame/packet/message loss is measured by LM, Loss Measurement.

A maintenance entity group in the OAM includes a maintenance endpoint (MEP, MEG End Point) located at both ends of the MPLS-TP transmission path, and a maintenance intermediate point (MIP) located in the middle of the MPLS-TP transmission path; When the transmission path fails, the source MEP sends a Lost Measurement Message (LMM, Loss Measurement Message) to the sink MEP, and then the MEP returns a Lost Measurement Response (LMR, Loss Measurement Response) to the source MEP, and the source MEP from the local information and The received information of the LMR comprehensively calculates the number of frame loss and the frame loss rate; wherein the LMM frame and the LMR frame are generally collectively referred to as an LM frame.

Usually when using the LM function to measure frame loss, the following parameters are required:

TxFCf: indicates the local frame count when transmitting the LMM;

RxFCf: indicates the local receive frame count when the LMM is received;

TxFCb: indicates the local frame count when transmitting the LMR;

When the source MEP sends the LMM, the TxFCf is written to the LMM; when the sink MEP receives When it reaches the LMM, copy the TxFCf in the received LMM to the LMR, and write the RxFCf and TxFCb to the LMR, and then the sinking MEP sends the LMR. When the source MEP receives the LMR, record the TxFCf and RxFCf in the LMR. , TxFCb, and the local receive frame count RxFCl at the time of receiving the LMR.

If the source MEP receives the LMR this time, the above count values are TxFCf[tc],

RxFCf[tc], TxFCb[tc], and RxFCl [tc], the last count values of the above are TxFCf[tp], RxFCf[tp], TxFCb[tp], and RxFCl [tp], respectively, the frame loss calculated by the source MEP Count as follows:

Frame Loss [far-end] = |TxFCf[tc]- TxFCf[tp]|-| RxFCf[tc]- RxFCf[tp]|; Frame Loss [near-end] = |TxFCb[tc]- TxFCb[tp] |-| RxFCl [tc]- RxFCl [tp]|. For the Ethernet network of the Y.1731 OAM application, because the destination address of the LM frame sent by the source MEP is a specific multicast address, only the MEP will identify and process the LM frame at a specific multicast address, and other nodes will directly transparently transmit the LM frame. The LM frame will not be processed and responded. For the MPLS-TP network of the G.8113.1 OAM application, the G-ACH (Generic Associated Channel) of the LM frame sent by the source MEP is a specific fixed value. There is also a transport label outside the -ACH header. The MIP transparently transmits the LM frame according to the transport label, and does not parse the G-ACH header. Therefore, the LM frame cannot be recognized. For the MEP node, the transport label is popped up. Furthermore, it is parsed into the G-ACH header, and it is determined whether or not the LM frame is processed based on whether the G-ACH is a specific fixed value, and therefore only the MEP node processes the LM frame.

In this way, in the prior art, only the MEP node can identify and process the LM frame. Therefore, the LM function can only be applied to determine the frame loss between the MEP nodes, and cannot be used for the frame loss measurement of the MIP node. Therefore, the LM function cannot be specifically located. The specific MIP node where the frame is lost. In addition, according to OAM regulations, only the MEP node counts the transmission and reception of frames, that is, there is no counting information about the transmission and reception frames on the MIP node, and the LM function is a measurement method for frame loss between nodes, when MIP When there is no counting of the transmitted and received frames on the node, it is impossible to determine the frame loss between the MEP and the MIP node. For details, refer to FIG. 1. The nodes SI and S6 are MEPs, and the other nodes S2 to S5 are MIPs. When an abnormality occurs between the nodes S3 and S4 and the service frame is lost, the nodes S1 and S6 can interact with each other through the LMM and the LMR. , can detect the frame loss, but because the frame loss cannot be measured between the MEP and the MIP node, the specific frame loss node cannot be detected. In the engineering application, only the specific MIP node that locates the dropped frame can further analyze the specific reason of the frame loss on the node and find the fundamental problem.

In summary, the LM function specified in OAM can solve the problem of frame loss measurement between MEPs, but LM in OAM can only be applied to frame loss measurement between MEP and MEP, which cannot be used for MEP and MIP. Frame loss measurement. In addition, some networks that do not support OAM, that is, no MEP nodes and no MIP nodes, also require a lost frame measurement to locate the fault. Summary of the invention

In view of this, the main object of the embodiments of the present invention is to provide a method and system for determining a lost frame, which can accurately locate a node that loses frames.

To achieve the above objective, the technical solution of the embodiment of the present invention is implemented as follows:

A method for determining a lost frame, the method comprising:

The first node and the second node that need to perform the lost frame measurement respectively count the respective frame counts;

The first node sends a measurement message frame including a frame count of the first node and an identifier that can be identified by the second node to the second node;

After receiving the measurement message frame, the second node sends a measurement response message frame including a frame count of the second node and an identifier that can be identified by the first node;

After receiving the measurement response message frame, the first node determines a frame loss situation between the first node and the second node;

The identifier that can be identified by the second node includes the purpose of the measurement message frame One or more of an address, a time-to-live (TTL), a type and/or a label, a pre-agreed identifier; the identifier that can be identified by the first node includes a destination address, a TTL, a type of the measurement response message frame And/or label, one or more of the pre-agreed identifiers.

The determining, by the first node, the measurement message frame that includes the frame count of the first node and the identifier that can be identified by the second node is:

The first node sets the destination address of the measurement message frame to the destination address of the second node, or sets the TTL of the measurement message frame to be the distance from the second node hop, or determines the type of the message frame and/or Or the label is set to a pre-agreed value, or after the pre-agreed identifier is set in the measurement message frame, the frame count of the first node is included in the measurement message frame for transmission.

The measurement response message frame in which the second node sends the frame count including the second node and the identifier that can be identified by the first node is:

The second node sets the destination address of the measurement response message frame to the destination address of the first node, or sets the TTL of the measurement response message frame to be the distance from the first node, or determines the response message frame. The type and/or label is set to a pre-agreed value, or after the pre-agreed identifier is set in the measurement response message frame, the frame count of the second node is included in the measurement response message frame for transmission.

The frame count is a count of receiving/transmitting frames of one or more combinations of ports, tunnels, and pseudowire layers that are pre-negotiated by the first node and the second node.

Further, the method further includes:

When the first node does not receive the measurement response message frame sent by the second node within a predetermined time, it is determined that all frames between the first node and the second node are lost.

A lost frame measurement system, the system includes: a first node and a second node; wherein, the first node is configured to perform statistics on a frame count when a frame loss measurement is required, and send the first node Frame count and determination of the identifier that can be recognized by the second node And the frame is sent to the second node; and configured to: after receiving the measurement response message frame sent by the second node, determining a frame loss situation between the first node and the second node;

The second node is configured to collect a frame count when the frame loss measurement needs to be performed, and send a frame count including the second node and an identifier that can be recognized by the first node after receiving the measurement message frame Measurement response message frame;

The identifier that can be identified by the second node includes one or more of a destination address, a TTL, a type, and/or a label of the measurement message frame, and a pre-agreed identifier; the identifier can be identified by the first node. The identifier includes the destination address, TTL, type, and

/ or label, one or more of the pre-agreed identifiers.

The first node is configured to set a destination address of the measurement message frame to a destination address of the second node, or set a TTL of the measurement message frame to be a distance from a second node, or The type of the message frame and/or the tag is set to a pre-agreed value, or after the pre-agreed identifier is set in the measurement message frame, the frame count of the first node is included in the measurement message frame for transmission.

The second node is configured to set a destination address of the measurement response message frame to a destination address of the first node, or set a TTL of the measurement response message frame to a hop count from the first node, Or setting the type and/or label of the measurement response message frame to a pre-agreed value, or setting the frame count of the second node in the measurement response message frame after setting the pre-agreed identifier in the measurement response message frame Send it.

Further, the first node is further configured to: when the measurement response message frame sent by the second node is not received within a predetermined time, determine that all frames between the first node and the second node are lost.

In the embodiment of the present invention, the interaction between the message frame and the measurement response message frame is performed between the nodes, Not only can the frame loss between MEP nodes in the network be measured, but also the frame loss between MEP and MIP, MIP and MIP nodes can be determined. Even when the network does not support 0 AM, two can be determined. Frame loss between nodes. In this way, when a failure occurs in the network and the frame is lost, the frame loss count of one node to another node can be determined. When there is a frame loss between two adjacent nodes, it can also be measured, which is beneficial to the network failure. Positioning, maintenance and management. DRAWINGS

1 is a schematic diagram of a method for determining a lost frame in an existing OAM network;

2 is a schematic flowchart of an implementation process of a lost frame measurement method according to an embodiment of the present invention;

3 is a schematic diagram of an implementation of a method for determining a lost frame according to an embodiment of the present invention; FIG. 4 is a schematic diagram of an implementation of a method for determining a lost frame according to an embodiment of the present invention; A schematic diagram of the implementation of the third embodiment; FIG. 6 is a schematic structural diagram of a lost frame measurement system according to an embodiment of the present invention. detailed description

The basic idea of the embodiment of the present invention is: the first node and the second node that need to perform the lost frame measurement respectively count the respective frame counts; the first node sends the frame count including the first node and can be recognized by the second node. Determining the message frame of the identifier to the second node; after receiving the measurement message frame, the second node sends a measurement response message frame including a frame count of the second node and an identifier that can be identified by the first node; After receiving the measurement response message frame, the first node determines a frame loss situation between the first node and the second node, where the identifier that can be identified by the second node includes the destination address of the measurement message frame. One or more of a time-to-live TTL, a type and/or a label, a pre-agreed identifier; the identifier that can be identified by the first node includes a destination address, TTL, type, and/or of the measurement response message frame One or more of the labels, pre-agreed identifiers.

In order to make the objects, technical solutions and advantages of the present invention more clear, the following embodiments are The invention will be described in further detail with reference to the accompanying drawings.

FIG. 2 is a flowchart showing an implementation process of a method for determining a lost frame according to an embodiment of the present invention. As shown in FIG. 2, the method includes the following steps:

Step 201: The first node and the second node that need to perform the lost frame measurement respectively count the respective frame counts;

Here, the first node and/or the second node may be a MEP, a MIP, or a node that does not support the OAM function, where, when the first node or the second node is a MIP or a node that does not support the OAM function, The first node or the second node counts the frame count as follows: According to the port receiving count, when the port receives a frame, the counter is incremented by one, and the value in the counter is the received frame count of the port; It can also be based on the frame count of a tunnel of a port. When a tunnel receives a frame, the counter is incremented by one. The value in the counter is the frame count based on a tunnel of the port.

In this manner, the frame count may be a count of the receiving/transmitting frame of one or more combinations of the port, the tunnel, and the pseudowire layer of the node; as long as the frame count of the pre-negotiated layer of the first node and the second node can be satisfied .

Step 202: The first node sends a measurement message frame including a frame count of the first node and an identifier that can be identified by the second node to the second node.

The identifier that can be identified by the second node includes one or more of a destination address, a TTL, a type, and/or a label, and a pre-agreed identifier of the measurement message frame. Here, the first node may The identifier that can be identified by the second node is set by: setting the destination address of the measurement message frame to the destination address of the receiving node (ie, the second node), or determining the lifetime of the message frame (TTL, Time to Live) Set to the second node hop count, or set the type, label, etc. of the measurement message frame to a pre-agreed value, or set a pre-agreed identifier in the measurement message frame.

Step 203: After receiving the measurement message frame, the second node sends the second node. a frame count and a measurement response message frame of the identifier that can be identified by the first node; wherein the identifier that can be identified by the first node includes a destination address, a TTL, a type, and/or a label of the measurement response message frame, Predefining one or more of the identifiers; here, the second node may set an identifier that can be recognized by the first node by: setting a destination address of the measurement response message frame as a receiving node (ie, the first node) The destination address of the response message frame is set to be the distance from the first node hop, or the type, label, etc. of the measurement response message frame is set to a pre-agreed value, or a pre-agreed identifier is set in the measurement response message frame. symbol.

Step 204: After receiving the measurement response message frame, the first node determines a frame loss situation between the first node and the second node.

Here, the first node determines a frame loss situation between the first node and the second node according to the frame count in the transmitted measurement message frame and the frame count in the received measurement response message frame.

In addition, the foregoing method further includes: determining, between the first node and the second node, when the first node does not receive the measurement response message frame sent by the second node for a preset time. All frames are lost.

3 is a schematic diagram of Embodiment 1 of a method for determining a lost frame according to an embodiment of the present invention, and FIG. 3 is a schematic diagram of an MPLS-TP network, where nodes S1 and S6 are MEPs, and other nodes S2 to S5 are MIPs; When a frame loss occurs between S3 and S4, if the frame loss measurement method between the MEPs of the prior art is used, although the frame loss can be detected on the path between the nodes S1 and S6, the frame loss cannot be detected. The specific node location.

According to the above method of the embodiment of the present invention, the nodes S2 to S5 that need to be measured first need to count the respective receiving and transmitting frame counts. Since the existing MEP nodes perform the statistics of the receiving and sending frames, only the nodes S2 to S5 need to be additionally performed. Frame count statistics;

The node S 1 then sends a measurement message frame to each MIP, in order to enable each MIP node to recognize and respond to the measurement message frame sent by the MEP node, the MEP node is transmitting the measurement message frame. Set the TTL to the hop count from the specified MIP. When the node receives the frame, if the TTL of the frame is greater than 1, the packet is forwarded and the TTL is decremented by 1. If the TTL of the frame is equal to 1, the Further parse and stop forwarding the frame. For example, when the TTL is set to 1, the measurement message frame sent by the node S1 is received by the node S2 and the response response message frame is returned. When the TTL is set to 2, the TTL of the measurement message frame sent by the node S1 is reduced by 1 when it is forwarded by the node S2. Then, the node S3 receives and replies to the measurement response message frame; when the TTL is set to be greater than or equal to the hop count between the MEP and the MEP (in this embodiment, the hop count between the nodes S1 and S6 is 5), the MEP The measurement message frame sent by the node S1 is received by the opposite MEP node S6 and replies to the measurement response message frame. It should be understood that FIG. 3 is only exemplified by the node S1 being sent to the nodes S3 and S4, wherein the TTL of the measurement message frame sent by the node S1 to S4 is set to 3, and the TTL setting of the measurement message frame sent by the node S1 to S3 is set. Is 2.

Note that although the TTL in this embodiment is the hop count between the sending node and the receiving node, it may also be other values calculated by the hop count, such as the hop count plus 1, the hop count minus 1, a certain comparison The large value minus the hop count, etc., as long as the response node and the sending node agree in advance.

The measurement message frame sent by the node S1 carries the frame count information of the node S1, and also carries the frame count information of the reply node in the measurement response message frame replied by each node, and the node S1 calculates its own and based on the information. After the frame loss counts between the MIP/MEP nodes, referring to FIG. 3, the node S1 can determine that there is no frame loss between the nodes S1 and S3, and the node S1 to the node S4 have dropped frames, so that the nodes S3 to S4 can be determined. The frame loss occurs. Therefore, the specific frame loss location is located between nodes S3 and S4. It may be that the node S3 or S4 has dropped frames, or the link between nodes S3 and S4 may be dropped.

The frame count information included in the measurement message frame and the measurement response message frame may be a count of the receiving/transmitting frame at the port, the tunnel, or the pseudowire layer, or multiple combinations of the foregoing counting, as long as the response node and the sending node Pre-negotiate can be.

FIG. 4 is a schematic diagram showing an implementation of Embodiment 2 of a method for determining a lost frame according to an embodiment of the present invention, such as As shown in FIG. 4, the measurement message frame sent by the node SI to the node S3 carries the number of transmission and reception frames of a tunnel under its own port 1; and the measurement response message frame replied by the node S3 carries both the received message from the node S1. Determining the tunnel receiving frame count copied in the message frame, and carrying the same frame transmission and reception frame count of the own port 3; after receiving the measurement response message frame, the node S1 determines the frame count and local in the response response message frame. The frame count calculates the frame loss value of the port 3 of the node S1 to the port 3 of the node S3 in the tunnel.

Similarly, the measurement message frame sent by the node S3 to the node S5 carries the transmission and reception frame count of a tunnel under its own port 2 and 3, and the measurement response message frame replied by the node S5 carries both the received message from the node S3. Determining the tunnel receiving frame counts copied in the message frame, and carrying the same frame transmission and reception frame counts of the own ports 4 and 5, and after receiving the measurement response message frame, the node S3 counts the frames according to the measurement response message frame. And the local frame count, calculate the frame loss value of the port 2, 3 of the node S3 to the port 4, 5 of the node S5 in the tunnel, if there is no frame loss between the port 2 of the node S3 and the port 4 of the node S5 If there is a frame loss between port 3 of node S3 and port 5 of node S5, it can be determined that there is a frame loss between port 4 and port 5 of node S5.

In addition, after the node sends the measurement message frame, if the measurement response message frame of the opposite end is not received within a predetermined time, for example, 5 seconds, it is determined that the frame loss count between the node and the opposite end is all frames.

FIG. 5 shows an implementation of Embodiment 3 of the method for determining a lost frame according to an embodiment of the present invention, and FIG. 5 shows an Ethernet or IP network, which uses the above method in the embodiment of the present invention, and the node to be measured (node S1~) S6) Statistics of the respective transmit and receive frame counts; the node S1 sends the measurement message frame to the other nodes, where the nodes S1 and S3 send the identifiers that can be recognized by the other party by setting the preset specific identifiers, and send them to the node at the node S1. The measurement message frame of S3 includes a specific identifier that can be identified by the node S3, and the measurement response message frame that the node S3 replies to the node S1 includes a specific identifier that can be identified by the node S1, and the identifier can be specifically Destination address, frame type, agreed value of a specific field, or a combination of the above, etc. The frame and the measurement response message frame also include the frame count information of the node, which may be a port, a virtual local area network (VLAN), or an IP layer receiving/transmitting frame count, or multiple combinations of the foregoing counting. As long as the response node and the sending node agree with each other in advance.

In order to determine the frame loss of the VLAN 100 in the Ethernet network, the node S1 sends a measurement message frame, and a specific location in the measurement message frame (for example, at the first address plus 100 bytes) contains a specific identifier that the node S3 can recognize. , if it can be 0x03030303, and includes the transmit and receive frame count of VLAN 100 of its own port 1;

The node S3 detects the corresponding specific location (ie, the first address plus 100 bytes), and when the content of the location is a pre-agreed specific identifier (ie, 0x03030303), the forwarding is not performed, but the response response message frame is returned, and The specific identifier written in the node S1 at a specific position in the measurement response message frame (for example, at the first address plus 120 bytes) may be 0x01010101, and the measurement response message frame further includes its own port 2, 3 After receiving the measurement response message frame, the node S1 detects the corresponding specific location, that is, whether the first address plus 120 bytes is a pre-agreed specific identifier (ie, 0x01010101), and if so, Instead of forwarding, the number of dropped frames from node S1 port 1 to node S3 ports 2 and 3 is calculated based on the received frame count and its own frame count.

Similarly, the node S1 calculates the frame loss count of its own port 1 to the node S4 port 4, 5 respectively. If there is a frame loss between the nodes S3 and S4, the node S1 can determine that there is no frame loss between the port 1 and the node S3, and there is a frame loss between the node S4 and the port 4, so that the frame loss position can be determined as a node. Between S3 and S4.

Further, if the nodes S3 and S4 are completely interrupted, the node S1 does not receive the measurement response message frame of the node S4 within a preset period of time (for example, 5 seconds), and at this time, the node S1 to the node S4 are determined. All frames are lost.

6 is a diagram showing the structure of a lost frame measurement system according to an embodiment of the present invention, as shown in FIG. The system includes: a first node and a second node; wherein

The first node is configured to perform statistics on a frame count when a frame loss measurement is required, and send a measurement message frame including a frame count of the first node and an identifier that can be identified by the second node to the second node; After receiving the measurement response message frame sent by the second node, determining a frame loss situation between the first node and the second node;

The second node is configured to collect a frame count when the frame loss measurement needs to be performed, and send a frame count including the second node and an identifier that can be recognized by the first node after receiving the measurement message frame The measurement response message frame.

A person of ordinary skill in the art may understand that all or part of the above steps may be completed by a program to instruct related hardware, and the program may be stored in a computer readable storage medium, such as Read-only memory, disk or CD, and so on. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware or in the form of a software function module. Embodiments of the invention are not limited to any specific form of combination of hardware and software.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Industrial applicability

In the embodiment of the present invention, by measuring the interaction between the message frame and the measurement response message frame between the nodes, not only the frame loss between the MEP nodes in the network can be determined, but also the MEP to MIP, the MIP to the MIP node can be determined. Frame loss, even when the network does not support 0 AM, it can also determine the frame loss between two nodes. According to the embodiment of the present invention, when a frame is lost due to a failure in the network, a frame loss count of a node to another node may be determined, and when there is a frame loss between two adjacent nodes, the frame may be detected. This facilitates the fault location, maintenance and management of the network.

Claims

claims

1. A lost frame measurement method, the method includes:

The first node and the second node that need to measure lost frames separately count their respective frame counts;

The first node sends a measurement message frame containing the frame count of the first node and an identifier capable of being recognized by the second node to the second node;

After receiving the measurement message frame, the second node sends a measurement response message frame including the frame count of the second node and an identifier that can be recognized by the first node;

After receiving the measurement response message frame, the first node determines the frame loss situation between the first node and the second node;

Wherein, the identifier that can be recognized by the second node includes one or more of the destination address of the measurement message frame, time to live TTL, type and/or label, and a pre-agreed identifier; the identifier that can be recognized by the first node The identifier identified by the node includes one or more of the destination address, TTL, type and/or label, and pre-agreed identifier of the measurement response message frame.

2. The method according to claim 1, wherein the first node sends a measurement message frame containing the frame count of the first node and an identifier that can be recognized by the second node as:

The first node sets the destination address of the measurement message frame to the destination address of the second node, or sets the TTL of the measurement message frame to the number of hops from the second node, or changes the type and/or the measurement message frame. Or the label is set to a pre-agreed value, or after the pre-agreed identifier is set in the measurement message frame, the frame count of the first node is included in the measurement message frame and sent.

3. The method according to claim 1, wherein the second node sends a measurement response message frame containing the frame count of the second node and an identifier that can be recognized by the first node as:

The second node sets the destination address of the measurement response message frame to the destination address of the first node, or sets the TTL of the measurement response message frame to the number of hops away from the first node, or Either set the type and/or label of the measurement response message frame to a pre-agreed value, or after setting the pre-agreed identifier in the measurement response message frame, include the frame count of the second node in the measurement response message frame. to send.

4. The method according to claim 1, wherein the frame count is the received/transmitted frame count of one or more combinations of port, tunnel, and pseudowire levels that have been agreed in advance by the first node and the second node.

5. The method according to claim 1, wherein the method further includes:

6. A lost frame measurement system, the system includes: a first node and a second node; wherein, the first node is configured to count frames when frame loss measurement needs to be performed, and send a message containing the first The frame count of the node and the measurement message frame of the identifier that can be recognized by the second node are sent to the second node; and it is also configured to determine the measurement response message frame between the first node and the second node after receiving the measurement response message frame sent by the second node. Frame loss situation;

The second node is configured to count frame counts when frame loss measurement is required, and after receiving the measurement message frame, send a frame count containing the second node and an identifier that can be recognized by the first node. Measurement response message frame;

Wherein, the identifier that can be recognized by the second node includes one or more of the destination address, TTL, type and/or label, and pre-agreed identifier of the measurement message frame; the identifier that can be recognized by the first node The identifier includes one or more of the destination address, TTL, type and/or label, and pre-agreed identifier of the measurement response message frame.

7. The system according to claim 6, wherein the first node is configured to set the destination address of the measurement message frame to the destination address of the second node, or to change the TTL of the measurement message frame. Set to the number of hops away from the second node, or set the type and/or label of the measurement message frame to a pre-agreed value, or after setting the pre-agreed identifier in the measurement message frame, include the frame count of the first node in The measurement message frame is sent.

8. The system according to claim 6, wherein the second node is configured to set the destination address of the measurement response message frame to the destination address of the first node, or to set the destination address of the measurement response message frame to The TTL is set to the number of hops away from the first node, or the type and/or label of the measurement response message frame is set to a pre-agreed value, or after the pre-agreed identifier is set in the measurement response message frame, the second node's TTL is set to a pre-agreed value. The frame count is included in the measurement response message frame and sent.

9. The system according to claim 6, wherein the frame count is the received/transmitted frame count of one or more combinations of port, tunnel, and pseudowire levels that have been agreed in advance by the first node and the second node.

10. The system according to claim 6, wherein the first node is further configured to determine the first node and the second node when the measurement response message frame sent by the second node is not received within a predetermined time. Frames between nodes are all lost.