WO2019047110A1

WO2019047110A1 - Delay measurement method and apparatus, and system in optical transport network

Info

Publication number: WO2019047110A1
Application number: PCT/CN2017/100928
Authority: WO
Inventors: 吴秋游; 苏伟
Original assignee: 华为技术有限公司
Priority date: 2017-09-07
Filing date: 2017-09-07
Publication date: 2019-03-14
Also published as: CN111052632A

Abstract

In an optical network, a network device sends an optical transport network (OTN) frame to another network device, and the overhead area of the OTN frame carries delay measurement overheads, the overheads comprising one timestamp. After the other said network device receives the OTN frame, the transmission delay from said network device to the other said network device is calculated according to the timestamp contained in the OTN frame and the time of receiving the OTN frame. Optionally, the other said network device may also send another OTN frame to said network device, the other said OTN frame containing one or more pieces of timestamp information. Said network device can determine, according to the timestamp information contained in the other said OTN frame and the time of receiving this OTN frame, one or more of one-way transmission delay and round-trip transmission delay between the two devices. The solution provided by the present application can support a plurality of types of delay measurements and realize high precision delay measurements.

Description

Method, device and system for time delay measurement in optical transport network

Technical field

The present application relates to the field of optical communications, and in particular to a delay measurement technique in an optical network.

Background technique

The optical transport network (OTN) is the core technology of the next-generation transport network. It has rich operation and management and maintenance (OAM) capabilities and powerful tandem connection monitoring (Tandem Connection Monitoring). TCM) capability and Forward Error Correction (FEC) capability enable flexible scheduling and management of large-capacity services. Because of these characteristics, OTN technology is increasingly becoming the mainstream technology of the backbone transmission network. As OTN is gradually deployed in the metropolitan area, the application scenarios for OTN are continuously expanded. For example: data center network, financial services, wireless pre-transmission and backhaul, short-distance metropolitan areas and other scenarios. The customer signals in these new scenarios are mostly sensitive to delay. That is to say, if the delay of the OTN path for transmitting these services does not meet the requirements, the service may not be opened normally. For example, in a wireless pre-transmission application scenario, a Common Public Radio Interface (CPRI) signal, an enhanced CPRI (eCPRI), and a Next Generation Fronthaul Interface (NGFI). The customer signal has strict specifications on the delay. If the delay introduced by the OTN is too large, the wireless front-end service cannot be opened normally.

Currently, the International Telecommunication Union-Telecommunication Standard Sector (ITU-T) defines a Delay Measurement (DM) field in the data frame structure of the OTN to implement the OTN path. Time delay measurement. Specifically, the method uses the OTN data frame of each rate to correspond to a specific time period, and calculates the bidirectional path delay information by using a network node to calculate the number of OTN frames received during the DM field hopping, that is, bidirectional The path delay is the OTN frame period multiplied by the number of received OTN frames. However, the measurement accuracy of this method is limited by the accuracy of the OTN frame period used. For example, an optical data unit 0 (ODU0, a type of OTN frame) has a time period of about 0.1 milliseconds. The above mentioned customer signals require a higher level of delay accuracy, for example: 1 microsecond level. Therefore, the measurement accuracy that the current method can provide cannot meet the delay accuracy requirements of the new scene mentioned above.

Therefore, a new delay measurement technique is needed to solve the problems faced by the above-mentioned delay measurement method.

Summary of the invention

Embodiments of the present invention describe methods, apparatus, and systems for time delay measurement to improve delay measurement accuracy in OTN.

In a first aspect, an embodiment of the present invention provides a method for measuring a delay in an optical network, where the method includes:

Receiving, by the first network device, a plurality of optical transport network (OTN) frames sent by the second network device, where an overhead area of each of the plurality of OTN frames carries a delay measurement overhead, and the overhead of the multiple OTN frames The time delay measurement overhead carried by the area carries a timestamp indicating that the second network device sends the multiple OTNs The time of the first OTN frame in the frame;

The first network device determines a transmission delay of the second network device to the first network device according to the timestamp and a time when the first network device receives the first OTN frame.

In one possible design, the delay measurement overhead is delimited based on a multiframe alignment signal (MFAS) included in the plurality of OTN frames to obtain the timestamp.

In one possible design, each of the OTN frames is an optical transmission unit k (OTUk) frame, an n*100G optical transmission unit (OTUCn) frame, or a flexible OTN (FlexO) frame.

In a possible design, the overhead area of each OTN frame is an overhead area of an optical transmission unit k (OTUk) frame, or an overhead area of an optical data unit k (ODUk) included in an OTUk frame, or an OTUk An overhead area of the optical payload unit k (OPUk) included in the frame; or, the overhead area of each OTN frame is an overhead area of an optical transmission unit (OTUCn) frame of n*100G, or n included in the OTUCn frame * The overhead area of the optical data unit (ODUCn) of 100G; or the overhead area of each OTN frame is the overhead area of the flexible OTN (FlexO) frame.

In a possible design, the delay measurement overhead carried by the overhead area of the multiple OTN frames transmits the node identification information of the first network device and the second network device. The node identifier information is a path trace identifier (TTI), an internet protocol (IP) address, or a medium access control (MAC) address.

In a second aspect, an embodiment of the present invention provides an optical network device, the device comprising a processor and a transceiver for supporting the first aspect and the various possible designs mentioned in the first aspect method. In particular, wherein the transceiver is operative to perform the receiving and transmitting actions in the method, and the processor is operative to support other processing steps of the above method.

In a third aspect, an embodiment of the present invention provides a method for measuring a delay in another optical network, where the method includes:

The first network device sends a plurality of first optical transport network (OTN) frames to the second network device, where an overhead region of each of the plurality of first OTN frames carries a delay measurement overhead, where the plurality of first The delay measurement overhead carried in the overhead area of the OTN frame transmits a first timestamp or measurement indication information, where the first timestamp indicates that the first network device sends the second OTN frame in the multiple first OTN frames The measurement indication information indicates that the first network device is performing delay measurement and the first network device acquires the first timestamp;

Receiving, by the first network device, a plurality of third OTN frames from the second network device, where the multiple third OTN frames deliver the first timestamp or the measurement indication information;

And the first network device determines, according to the first timestamp, a time when the first network device receives the fourth OTN frame corresponding to the second OTN frame in the multiple third OTN frames A two-way transmission delay between the first network device and the second network device.

In a possible design, the plurality of third OTN frames further pass a second timestamp and a third timestamp, the second timestamp indicating that the second network device receives the second OTN frame The time, the third timestamp indicates the time when the second network device sends the fourth OTN frame, and the method further includes:

The bidirectional transmission delay is modified according to the second timestamp and the third timestamp.

In one possible design, the delay measurement overhead is delimited according to a multiframe alignment signal (MFAS) included in the plurality of first OTN frames to obtain the first timestamp.

In a possible design, each of the first OTN frames and each of the third OTN frames is optical transmission Transmission unit k (OTUk) frame, n*100G optical transmission unit (OTUCn) frame or flexible OTN (FlexO) frame.

In a possible design, the overhead area of each of the first OTN frame and each of the third OTN frames is an overhead area of an optical transmission unit k (OTUk) frame, or an optical data unit included in the OTUk frame. An overhead area of k(ODUk), or an overhead area of an optical payload unit k (OPUk) included in an OTUk frame; or an overhead area of each of the first OTN frames and each of the third OTN frames An overhead area of an optical transmission unit (OTUCn) frame of n*100G, or an overhead area of an optical data unit (ODUCn) of n*100G included in the OTUCn frame; or, each of the first OTN frames and each of the The overhead area of a third OTN frame is the overhead area of a flexible OTN (FlexO) frame.

In a possible design, the delay measurement overhead carried by the overhead area of the multiple first OTN frames transmits the node identification information of the first network device and the second network device. The node identifier information is a path trace identifier (TTI), an internet protocol (IP) address, or a medium access control (MAC) address.

In one possible design, the method further includes:

Determining, by the first network device, a transmission delay of the first network device to the second network device according to the first timestamp and a time when the first network device receives the fourth OTN frame At least one of a transmission delay of the second network device to the first network device.

In a fourth aspect, an embodiment of the present invention provides an optical network device, the device comprising a processor and a transceiver for supporting the third aspect and the various possible designs mentioned in the third aspect method. In particular, wherein the transceiver is operative to perform the receiving and transmitting actions in the method, and the processor is operative to support other processing steps of the above method.

In a fifth aspect, an embodiment of the present invention provides an optical transport network (OTN) frame structure, where the frame structure includes a fixed frame area, an optical transmission unit OTU overhead, an optical data unit ODU overhead, an optical payload unit OPU overhead, An OPU payload area and a forward error correction FEC area, the ODU overhead including a delay measurement overhead; or, the frame structure includes a fixed frame area, a flexible OTN (FlexO) overhead area, a FlexO payload area, and an FEC area, The FlexO overhead area includes the delay measurement overhead; wherein:

The delay measurement overhead carries partial information of at least one timestamp, the at least one timestamp being used to support delay measurement between two devices using the OTN frame structure.

In a possible design, the frame structure further includes a multiframe alignment signal (MFAS), the frame structure delimiting the delay measurement overhead by using the MFAS field to obtain the at least one timestamp .

In a possible design, the delay measurement overhead further carries a part of information of the node identification information of the two devices. The node identifier information is a path trace identifier (TTI), an internet protocol (IP) address, or a medium access control (MAC) address.

In a sixth aspect, an embodiment of the present invention provides a method for measuring a time delay in an optical network, where the method includes:

The first network device receives a plurality of first optical transport network (OTN) frames from the second network device, where an overhead region of each of the plurality of first OTN frames carries a delay measurement overhead, the multiple first The delay measurement overhead carried in the overhead area of the OTN frame transmits a first timestamp or measurement indication information, where the first timestamp indicates that the second network device sends the second OTN frame in the multiple first OTN frames The measurement indication information indicates that the second network device is performing delay measurement;

Transmitting, by the first network device, a plurality of third OTN frames to the second network device, the multiple third OTNs The frame transmits the first timestamp or the measurement indication information to cause the second network device to measure a bidirectional transmission delay according to the first timestamp.

In a possible design, the multiple third OTN frames further carry a second timestamp and a third timestamp, the second timestamp indicating that the first network device receives the second OTN frame Time, the third timestamp indicating a time when the first network device sends the fourth OTN frame, wherein the second timestamp and the third timestamp are used to modify the two-way transmission delay.

In a possible design, the first network device delimits the delay measurement overhead according to a multiframe alignment signal (MFAS) included in the plurality of first OTN frames to obtain the first timestamp. .

In a possible design, each of the first OTN frames and each of the third OTN frames are an optical transmission unit k (OTUk) frame, an n*100G optical transmission unit (OTUCn) frame, or a flexible OTN ( FlexO) frame.

In a possible design, the overhead area of each of the first OTN frame and each of the third OTN frames is an overhead area of an optical transmission unit k (OTUk) frame, or an optical data unit included in the OTUk frame. An overhead area of k (ODUk), or an overhead area of an optical payload unit k (OPUk) included in the OTUk frame; or, an overhead area of each of the first OTN frame and each of the third OTN frames is An overhead area of an optical transmission unit (OTUCn) frame of n*100G, or an overhead area of an optical data unit (ODUCn) of n*100G included in the OTUCn frame; or, each of the first OTN frames and each of the The overhead area of the third OTN frame is the overhead area of the flexible OTN (FlexO) frame.

In a seventh aspect, an embodiment of the present invention provides an optical network device, the device comprising a processor and a transceiver for supporting the sixth aspect and the various possible designs mentioned in the sixth aspect method. In particular, wherein the transceiver is operative to perform the receiving and transmitting actions in the method, and the processor is operative to support other processing steps of the above method.

In an eighth aspect, an embodiment of the present invention provides a computer storage medium for storing computer software instructions for use in the apparatus mentioned in the second aspect, the fourth aspect, or the seventh aspect, comprising Aspect of the program designed.

In a ninth aspect, an embodiment of the present invention provides a system for one-way delay measurement, the system comprising the network device mentioned in the second aspect and another network device. The another network device is configured to send the plurality of OTN frames to the network device mentioned in the second aspect.

In a tenth aspect, an embodiment of the present invention provides another system for two-way delay measurement or multiple delay measurements, the system comprising the network device mentioned in the fourth aspect and the seventh aspect mentioned Network equipment.

Compared with the prior art, the solution provided by the embodiment of the present invention carries the delay measurement overhead in the OTN frame, and the overhead carries at least one time stamp, thereby supporting the OTN node to perform high-accuracy delay measurement.

DRAWINGS

The embodiments of the present invention will be described in more detail below with reference to the accompanying drawings:

FIG. 1 is a schematic diagram of a possible application scenario according to an embodiment of the present invention;

2 is a schematic diagram of a hardware structure of a possible optical transmission network device;

3 is a schematic diagram of a possible high-precision delay measurement overhead in an OTUk frame;

4 is a schematic diagram of a possible high-precision delay measurement overhead in a FlexO frame;

FIG. 5 is a schematic diagram of a field included in a possible high-precision delay measurement overhead;

6 is a schematic diagram of a possible high-precision delay measurement overhead delimiting;

7 is a schematic diagram of a field included in another possible high-precision delay measurement overhead;

Figure 8 is a flow chart showing a possible high-precision time delay measurement;

Figure 9 is a flow chart showing another possible high-precision time delay measurement;

Figure 10 is a schematic diagram of still another possible high precision time delay measurement;

FIG. 11 is a schematic structural diagram of a possible network device.

Detailed ways

The network architecture and the service scenario described in the embodiments of the present invention are intended to more clearly illustrate the technical solutions of the embodiments of the present invention, and do not constitute a limitation of the technical solutions provided by the embodiments of the present invention. A person skilled in the art can understand that the technical solutions provided by the embodiments of the present invention are applicable to similar technical problems as the network architecture evolves and new service scenarios appear.

General overview:

The embodiments of the present invention are applicable to an optical network, such as an optical transport network (OTN). An OTN is usually connected by multiple devices through optical fibers. It can be composed of different topology types such as line type, ring shape and mesh type according to specific needs. The OTN shown in Figure 1 is a mesh network consisting of eight network devices. An OTN device may have different functions depending on actual needs. In general, OTN devices are classified into optical layer devices, electrical layer devices, and opto-electric hybrid devices. The optical layer device refers to a device capable of processing an optical layer signal, such as an optical amplifier (Optical Amplifier, OA for short) and an optical add-drop multiplexer (OADM). The OA can also be called an Optical Line Amplifier (OLA), which is mainly used to amplify an optical signal to support transmission of a longer distance while ensuring the specific performance of the optical signal. OADM is used to spatially transform optical signals so that they can be output from different output ports (sometimes referred to as directions). Depending on the capabilities, OADM can be divided into fixed OADM (Fixed OADM, FOADM for short) and configurable OADM (Reconfigurable OADM, ROADM for short). A electrical layer device refers to a device capable of processing an electrical layer signal, for example, a device capable of processing an optical data unit (ODU) signal. An opto-electric hybrid device refers to a device that has the ability to process optical layer signals and electrical layer signals. It should be noted that an OTN device can aggregate multiple devices with different functions according to specific integration requirements. The invention is applicable to OTN devices of different forms and integrations.

Figure 2 shows the hardware structure of an OTN device. Specifically, an OTN device includes a power supply, a fan, and an auxiliary board, and may also include a tributary board, a circuit board, a cross board, an optical layer processing board, and a system control and communication type board. It should be noted that the type and number of boards included in each device may be different according to specific needs. For example, a network device that is a core node may not have a tributary board. A network device that is an edge node may have multiple tributary boards. The power supply is used to power the OTN equipment and may include primary and backup power supplies. The fan is used to dissipate heat from the device. Auxiliary boards are used to provide external alarms or access auxiliary functions such as an external clock. The tributary board, the cross board and the circuit board are mainly used to process the electrical layer signals of the OTN (hereinafter referred to as the ODU letter). Number, OTN frame, or ODU data frame). The tributary board is used for receiving and transmitting various customer services, such as SDH service, packet service, Ethernet service, and pre-transmission service. Further, the tributary board can be divided into a customer side optical module and a signal processor. The client side optical module may be an optical transceiver for receiving and/or transmitting a client signal. The signal processor is used to implement mapping and demapping processing of the client signal to the ODU frame. The cross-board is used to implement the exchange of ODU frames to complete the exchange of one or more types of ODU signals. The circuit board mainly implements processing of the line side ODU frame. Specifically, the circuit board can be divided into a line side optical module and a signal processor. The line side optical module may be a line side optical transceiver for receiving and/or transmitting an ODU signal. The signal processor is used to implement multiplexing and demultiplexing of the ODU frame on the line side, or mapping and demapping processing. System control and communication boards are used to implement system control and communication. Specifically, information can be collected from different boards through the backplane, or control commands can be sent to the corresponding boards. It should be noted that, unless otherwise specified, a specific component (for example, a signal processor) may be one or more, and the present invention does not impose any limitation. It should be noted that the embodiment of the present invention does not impose any limitation on the type of the board included in the device, and the specific functional design and quantity of the board.

On the electrical layer, the OTN frame processed by the OTN device may adopt a frame format defined by the International Telecommunication Union-Telecommunication Standard Sector (ITU-T), for example, G.709 standard and G. 709.1 standards, etc., to achieve interoperability between devices. This application improves the current ITU-T defined OTN frame format to support the device to achieve high-precision delay measurement. It should be noted that, for the standard existing frame format definition, that is, the existing frame format includes specific field definitions, the present invention is only mentioned when needed. A complete OTN frame format definition of the prior disclosure can be easily obtained by those skilled in the art, and details are not described herein.

The OTN standard defines different types of OTN frames, such as: Optical Transport Unit k (OTUk) frame, n*100G Optical Transport Unit Cn (OTUCn) frame, flexible OTN interface (Flexible) OTN Interface, referred to as FlexO) frames, etc. The information newly added to support the delay measurement in an OTN frame will be described below with reference to more drawings. It should be noted that, in order to distinguish the newly defined delay measurement overhead field and the delay measurement (DM) field defined in the prior art, the present invention collectively refers to the newly defined delay measurement overhead field as high-precision delay measurement. (High precision Delay Measurement, referred to as HDM) overhead. However, the HDM overhead is essentially a delay measurement overhead, and it can be given other names. For example: a delay measurement overhead with high precision performance. Another example: a delay measurement overhead that provides high-precision delay capability.

The information in the HDM overhead (as shown in the example in Figure 5) occupies more bytes. It is generally contemplated by those skilled in the art that this overhead is placed into the payload area of the OTN frame (e.g., the optical payload unit payload area shown in Figure 3) so that the carrying of HDM overhead can be accomplished by one OTN frame. The number of bytes in the overhead area of an OTN frame is limited, so how to efficiently carry the HDM overhead is a complicated problem that needs to be solved. Not general, the following description will take the overhead area of the OTN frame with the HDM overhead as an example. The following description also applies to placing this overhead in a scenario in the load zone.

Figure 3 shows an example of the location of HDM overhead in an OTUk frame. As shown in FIG. 3, an OTUk frame includes a fixed frame area, an optical transmission unit overhead (hereinafter referred to as OTU OH), an optical data unit overhead (hereinafter referred to as ODU OH), an optical payload unit overhead (hereinafter referred to as OPU OH), and an OPU. Payload area and forward error correction (hereinafter referred to as FEC) area. It can be seen that an OTUk frame contains an ODUk frame. Both are a kind The main difference between OTN frames is that the former contains more overhead. The OPU payload area is used to carry customer data. The various overheads mentioned above are used to implement the operation, maintenance and management functions of the optical transport network. The FEC area is used to correct bit errors that may exist in data frame transmission. It should be noted that k in the OTUk frame represents the rate level of one OTU signal, and different k values correspond to different frame rates (sometimes also frame periods).

To implement delay measurement, a high-precision delay measurement (HDM) overhead is added to the OTUk frame to carry the information needed for the delay measurement. For example: in the OTU OH of an OTUk frame. Another example: in its ODU OH. The example shown in FIG. 3 is a HDM overhead carrying 2 bytes at the 1st byte and the 2nd byte in the ODU OH.

Figure 4 shows an example of the location of the delay measurement overhead in a FlexO frame. As shown, a FlexO overhead structure contains 8 multiframes (ie, m=8 in FIG. 4), where each multiframe includes a fixed frame area, an overhead area, a clear area, and an FEC area (FIG. 4 does not show ). The field that may be used by the present invention is a MFAS (Multi-Frame Alignment Signal) field. This field is used to indicate the location information of an OTN frame in an OTN multiframe. Take the length of 256 as an example (ie, an OTN multiframe consists of 256 OTN frames). Starting from 0, the value of this field is incremented based on the increase in the number of OTN frames until it counts to 255, and then resets to the next frame. 0, start a new round of multiframe indication. It should be noted that the MFAS of the FlexO frame adopts an 8-multiframe loop mode, and the OTUk frame shown in FIG. 3 also includes an MFAS field (not shown). It should also be noted that the RES of FIG. 4 is a reserved field.

It should be noted that FIG. 3 and FIG. 4 are only examples of HDM overhead, and the present invention does not impose any limitation on the location of the HDM overhead in an OTN frame. That is, this overhead can be anywhere in an OTN frame. It should also be noted that the first and second bytes in the ODU OH of the OTUk in the current OTN standard are reserved fields. Therefore, placing HDM overhead in this location does not have any impact on existing features. To simplify the description, the following uses the HDM overhead to describe the first and second bytes in the ODU OH of an OTUk frame as an example. Unless otherwise stated, the following description of the inclusion of specific fields for HDM overhead and the embodiments described below are also applicable to other types of OTN frames. For example: ODUCn frame. Another example: FlexO frames.

The upper half of Figure 5 gives the fields covered by the HDM overhead. Specifically, the HDM overhead includes:

Node ID (1 byte): This field is used to indicate the source node ID and the destination node (sometimes called the sink node) identifier of the service path (or path segment) in which the delay measurement is performed. In general, in order to be able to uniquely identify a node, the length of the field is usually greater than one byte, so the field can be resolved by means of the previously mentioned MFAS field. That is to say, this field of multiple OTN frames needs to be indicated to indicate a complete node identification information. For example, if the length of the source node and the destination node identifier are both 16 bytes, in order to be able to give the node identification information completely, an OTN multiframe of length 32 is required (ie, 32 OTN frames are included, and the MFAS field passes through 0. -31 to identify). For more examples, see the following information about the information contained in the node identification field, which is not described here. It should be noted that, in this application, a node can be understood as a network device.

Measurement indication (1 byte): This field is used to indicate the indication information needed for the delay measurement, such as may include a timestamp, a control field, and the like. It should be noted that similar to the node identification field, this field may also need to be parsed by means of the MFAS field. The method of specific analysis is similar, and will not be described here.

The lower half of Figure 5 further gives an example of the specific fields contained in each field, which are described separately below. It should be noted that the following description is based on the case where the multiframe size is 64 (ie, MFAS is 0 to 63). According to the needs of specific applications, the length of the multiframe may be different, and even the multiframe may not be used. What is the limit. It should be noted that one field is used to convey information, but one information may require one or more fields to be completely represented. That is, a field may represent a complete message or just a part of it.

The node identifier may be a Trail Trace Identifier (TTI), an Internet Protocol (IP) address, a Media Access Control (MAC) address, or the like. It can also be the only name that can identify a node, usually expressed in characters or numbers. Specifically, an example given by the node identification field shown in FIG. 5 is a TTI. Specifically, the field further includes the following fields:

SAPI: Source Access Point Identifier, source access point identifier, occupying 16 bytes of MFAS=0 to 15, used to indicate the source node for delay measurement;

DAPI: Destination Access Point Identifier, the destination access point identifier, which occupies 16 bytes of MFAS=16 to 31, and is used to indicate the destination node for performing delay measurement;

Operator specified field: 32 bytes occupying MFAS=32 to 63 for transmitting operator-defined information content. It should be noted that this field is an optional field.

It should also be noted that the specific coding methods of SAPI and DAPI can refer to the ITU-T T.50 technical specification or the address coding specifications of other existing standard organizations.

As shown in FIG. 5, the measurement indication field is different according to the direction in which the HDM overhead is located, and the information included is different. Specifically, the HDM overhead sent by the source node to the destination node is referred to as an HDM information frame, and the information that may be included is as follows:

Control field: This field includes some control parameters required for the delay measurement, and the specific information/fields are as shown in Table 1. It should be noted that this field is an optional field. If the information is not carried in the OTN frame, the information can be configured to the corresponding node by other means, for example, through a controller or other external server.

Table 1 shows the information contained in the control field.

TxTimeStamp: This field is used to indicate that the source node sends time information of the OTN frame carrying the HDM overhead. It should be noted that, in a specific implementation, the HDM information frame does not need to carry the time information, and Replaced by other information. Specifically, refer to the specific description of Embodiment 2, and details are not described herein.

Reserved field: No actual meaning, optional field.

FCS: Frame Check Sequence, frame check sequence, CRC16 (Cyclic Redundancy Check) can be used to perform cyclic redundancy check on HDM overhead. This field is optional.

It should be noted that the above four fields occupy 2 bytes, 8 bytes, 20 bytes, and 2 bytes, respectively, and need to use the overhead position corresponding to multiple OTN frames in one multiframe.

The HDM overhead sent by the destination node to the source node is called an HDM response frame, which may contain the following fields:

Control field: The meaning of the HDM information frame contains the description of the field, which is not described here. It should be noted that the destination node can directly extract relevant information from the HDM information frame received by it to the HDM response frame. That is to say, the destination node sets the same information as the source node.

TxTimeStamp, RxTimeStamp, TxTimeStamp': These three are timestamps, respectively used to indicate the time when the source node sends the OTN frame containing the HDM information frame, the time when the destination node receives the OTN frame, and the destination node sends the OTN frame containing the HDM response frame. time. It should be noted that the last two timestamps are not mandatory. Specifically, refer to the description of Embodiment 1, and no further description is made here.

Reserved fields and FCS: The meanings of the HDM information frame include fields, which are not described here.

It should be noted that the above four fields occupy 2 bytes, 8 bytes, 8 bytes, 8 bytes, 4 bytes, and 2 bytes, respectively, and need to be delimited by the MFAS. It should also be noted that the timestamp mentioned above (sometimes referred to as timestamp) can take a common timestamp of 8 bytes, 10 bytes or other bytes (support accuracy is generally 1 nanosecond or even higher). Accuracy). Specifically, reference may be made to the time stamp defined in the 1588 standard of the Institute of Electrical and Electronics Engineering (IEEE).

It should also be noted that, as in the example of FIG. 5, the HDM information frame and the HDM response frame do not appear at the same time. That is to say, the OTN frame sent by the source node to the sink node contains the HDM information frame, and the reverse direction includes the HDM response frame. Therefore, the MFAS counts they use are repeatable. Yet another way is to assign non-overlapping MFAS count segments to two different types of frames. The present invention does not limit the method of the specific design. In general, because of the direction of measurement for one delay, it is not possible to have both overheads at the same time. Therefore, the former can save network overhead.

In order to clearly explain how the above-mentioned measurement indication field of HDM overhead is delimited by means of the MFAS field, FIG. 6 gives a specific example. The so-called delimitation refers to the definition of how to generate and parse a message. Taking a complete measurement indication information as 32 bytes as an example, the MFAS has a value range of 0-255 to represent a multiframe. Then, within one cycle of the MFAS, eight measurement indication information can be indicated. Specifically, the measurement indication field in the OTN frame with the MFAS value of 0-31 constitutes a complete measurement indication information. Similarly, the MFAS is 32-63 and so on, and the measurement indication field of every 32 OTN frames constitutes the second to eighth complete measurement indication information. The node receiving the corresponding OTN frame parses the measurement indication field in this way (ie by means of the MFAS field). It should be noted that when a network device generates an OTN frame containing HDM overhead, it also needs to split the HDM information by using MFAS to be placed in different OTN frames.

In addition, there are other ways to delimit the HDM overhead. For example, using the Genera Framing Procedure (GFP) or Advanced Data Link Control (High-level Data Link) Control, referred to as HDLC), is encapsulated. Specifically, FIG. 7 shows an example of an HDM information frame and an HDM response frame. In this way of framing with other protocols, the HDM overhead sent by one node contains complete information. For example, the HDM information frame and the HDM corresponding frame both contain the source address and the destination node identification information. It should be noted that this is not substantially different from the previous information adopted by MFAS delimitation, only how the node determines the starting position of the received overhead is different. The MFAS delimiting method adopts the existing delimiting method of OTN frames, which is simpler. Other protocol framing methods require adding a frame header (ie, supporting a new encapsulation protocol) so that the node receiving the OTN frame correctly identifies and parses the HDM overhead by identifying the encapsulation protocol. It should be noted that the example of the field included in the HDM overhead shown in FIG. 7 is mentioned in the related fields in FIG. 6 described above, and details are not described herein again.

It should also be noted that the delay measurement mentioned in this application refers to the transmission delay between two nodes. Specifically, the transmission delay refers to the delay experienced by an OTN data frame after passing through a path or a path segment. This delay can include the delay introduced by the link (ie, fiber). It can also include the delay introduced by the node. Depending on the specific needs, the measurement may be a one-way transmission delay or a two-way transmission delay. For example, in Figure 1, the one-way transmission delay from node N1 to node N5 can be measured. The node that performs the measurement may be N5 or a node having an associated delay parameter (for example, the aforementioned timestamp). For a specific description, refer to Embodiment 1. As another example, the measured may be a two-way transmission delay from node N1 to node N5 upon returning to node N1. Among them, the node that performs measurement is usually node N1. However, it can also be other devices with relevant time parameters. For a detailed description, refer to Embodiment 2.

It should also be noted that latency refers to time delay, sometimes referred to as delay or delay. For convenience of description, the present invention is unified into a delay. In addition, it should also be noted that the service path and the delay measurement path are two concepts that will appear in subsequent embodiments. A business path is a path that is used to deliver a particular business data. It usually consists of a series of nodes: the node that sends the service is called the source node of the service path, and the last node that receives the service is the sink node (or destination node) of the service path. Between the source node and the destination node, there may also be one or more intermediate nodes, which may also be referred to as nodes for forwarding service data. However, the delay measurement path refers to the path for performing the delay measurement. It may be equal to the business path or a business path segment. That is to say, the source node and the destination node of the delay measurement path are not necessarily the source node and the destination node of the service path, but may be any two nodes on the service path. Specifically, refer to the examples of Embodiments 1-4.

The embodiments of the present invention will be further described in detail below based on the common aspects of the present invention relating to HDM overhead. It should be noted that the terms "first", "second" and the like in the following embodiments of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or order. It is to be understood that the data so used may be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than what is illustrated or described herein.

Example 1:

One embodiment of the present invention provides a method, apparatus, and system for time delay measurement in an optical network. The OTN frame format used by the nodes mentioned in this embodiment contains the HDM overhead mentioned in the "Overall Summary" section. In the specific description, only some specific fields of the HDM overhead are included as an example. Specifically, the HDM overhead may include information such as TTI and TxTimeStamp. However, the method steps of this embodiment are also applicable to the above-mentioned part mentioning HDM overhead including different fields, and different HDM overhead delimiting methods.

It should be noted that the present invention only describes a single measurement method of one-way delay. Other types of delay measurements For the method of the multiple parallel delay measurement, refer to the description of Embodiment 2-4, and no further details are provided herein.

The network shown in Fig. 1 used in this embodiment is assumed. The node N1 passes through the nodes N2, N3, and N4, and the N5 is an example of a service path. It is assumed that the portion in which the delay measurement is required is N1-N2-N3-N4, which is simply referred to as the delay measurement path in FIG. It can be seen that in this embodiment, the delay measurement path is a part of the service path, that is, one service path segment. It should be noted that a delay measurement path may be an ODUk, an ODUflex (Flexible ODU, a flexible ODU, which is one type of an OTN frame) or all or a segment of an ODUCn path, or may include a FlexO link, etc., and the present invention does not Any restrictions.

It should also be noted that, in order to perform the delay measurement, the network node in this embodiment needs to have a time synchronization mechanism. For example, the 1588 standard is adopted. That is to say, the resolution of a timestamp by different nodes is accurate to ensure that the calculated delay is accurate. In order to support the one-way delay measurement mentioned in this embodiment, the HDM information frame of the HDM overhead includes at least time information for transmitting an OTN frame, for example, a TxTimeStamp field. However, HDM response frames are not required.

The steps of the time delay measurement are further described below in conjunction with FIG.

In the 801 part, the node N1 sends a plurality of optical transport network (OTN) frames, and the overhead area of each of the plurality of OTN frames carries a delay measurement overhead, and the time zone carried by the multiple OTN frames The delay measurement overhead passes a timestamp indicating the time when the N1 sends the first OTN frame in the multiple OTN frames;

The receiving device of the plurality of OTN frames is a node N4. Specifically, the delay measurement overhead is the HDM overhead mentioned in the foregoing section; the timestamp is the TxTimeStamp mentioned in the “Overall Overview” section. It should be noted that the OTN frame may further include TTI information, so that the destination node N4 determines that it is the destination node of the delay measurement path, that is, needs to calculate the transmission delay. If the OTN frame does not include the TTI information, the calculation of the transmission delay may be driven by N4 by configuring the N4 node in advance. Compared with the latter, the former method is more flexible, and different nodes can be triggered to perform delay measurement as needed.

It should also be noted that the first OTN frame refers to any one of a plurality of OTN frames. The device receiving and transmitting the OTN frame can negotiate the location of this first OTN frame in the OTN frame in the HDM overhead. Alternatively, the location of the first OTN frame may be set in advance by the network management system.

Finally, it should be noted that the overhead area of an OTN frame carries only part of the timestamp information. The receiving device needs to combine the partial time stamp information included in the received multiple OTN frames to obtain a complete time stamp. That is to say, for the number of multiframes that need to be occupied for the delay measurement (corresponding to a certain range of MFAS values), the related device needs to know in advance (for example, a device such as a head node) or pass the information through overhead (for example) : If you support multiple types of lengths of HDM overhead, you can pass the specific types supported by the overhead.).

In section 802, a transmission delay from the node N1 to the node N4 is determined according to the timestamp and the time at which the node N4 receives the first OTN frame.

Specifically, if the time of receiving the first OTN frame is RxTime, the transmission delay of N1 to N4 can be obtained by RxTime-TxTimeStamp calculation.

It should be noted that N1 and N4 in this step are only one example, and may be replaced by the first network device and the second network device.

It should also be noted that the node performing the delay calculation may also be another subject. For example, after receiving a timestamp information, N4 determines the time when it receives the first OTN frame, and it can send these time parameters to the network. The network controller or other device dedicated to the collection of delay information is used for calculation, and the present invention does not impose any limitation.

Depending on the specific needs, the HDM overhead can also contain control fields to achieve flexible control of latency measurements. In this embodiment, if the HDM overhead includes a control field, the value of the DMtype field may be 0001 as shown in Table 1. If periodic measurements are required, the DMma field takes the value 0001; if it is only one measurement, it can be set to 0010 as shown in Table 1. The location information of the first OTN frame mentioned above can also be carried by the control field.

It should be noted that the embodiment of the present invention does not impose any restrictions on the location (OTU overhead or ODU overhead, etc.) and the frame type (FlexO or OTUk or OTUCn, etc.) that specifically carry the HDM overhead.

By carrying the delay measurement overhead in the OTN frame, the overhead carries at least one partial information of the timestamp, and a complete timestamp information is transmitted through multiple OTN frames, and the node can perform high-precision delay measurement. Compared with the existing methods, the method can support one-way delay measurement and can support more accurate measurement.

It should be noted that the method of carrying the HDM overhead in the overhead area of the OTN data frame can improve the transmission efficiency compared with the method of placing the overhead in the payload area. That is to say, the former completes the delay measurement without occupying the bandwidth carrying the service data, thereby being more efficient. This makes it possible to monitor the delay of the service path while the service is being transmitted, so as to adjust the service path when necessary. For example, if the path delay of the current bearer service data is deteriorated to meet the delay requirement of the service, the node can actively modify the service path. That is to say, by carrying the delay measurement overhead in the overhead area of the OTN, the bandwidth of the service data is not occupied, and the network bandwidth utilization is improved.

Optionally, by carrying the node identifier information, the method may support flexible configuration of the delay measurement path, or verify the configuration information on the premise that the first and last nodes of the delay measurement have been configured.

Example 2:

One embodiment of the present invention provides a method, apparatus, and system for delay measurement in another optical network. The OTN frame format used by the nodes mentioned in this embodiment contains the DHM overhead mentioned in the "Overall Summary" section. In the specific description, only some specific fields of the HDM overhead are included as an example. Specifically, the HDM overhead may include information such as TTI and TxTimeStamp, RxTimeStamp, and TxTimeStamp'. However, the method steps of this embodiment are also applicable to the HDM overhead including a different number of fields mentioned in the "Overall Summary" section, as well as different DM overhead delimiting methods.

It should be noted that the present invention only describes a single measurement method of two-way delay. Other types of delay measurement and multiple parallel delay measurement methods are specifically described in the description of Embodiments 1 and 3-4, and are not described herein.

The network shown in Fig. 1 used in this embodiment is assumed. The node N1 passes through the nodes N2, N3, and N4, and the N5 is an example of a service path. It is assumed that the portion in which the delay measurement is required is N2-N3-N4, which is simply referred to as the delay measurement path in FIG. It can be seen that in this embodiment, the delay measurement path is a part of the service path, that is, one service path segment. It should be noted that the node of this embodiment, similar to the embodiment 1, also has a mechanism of time synchronization. In order to support the delay measurement mentioned in this embodiment, the HDM information frame of the HDM overhead may include time information for transmitting an OTN frame, for example, a TxTimeStamp field.

The steps of the two-way delay measurement are further described below with reference to FIG.

In the 901 part, the node N2 sends a plurality of first OTN frames, and the overhead area of each OTN frame of the plurality of first OTN frames carries a delay measurement overhead, which is carried by the overhead area of the multiple first OTN frames. Delay measurement overhead Transmitting a first timestamp, where the first timestamp indicates a time when N2 sends the second OTN frame in the plurality of first OTN frames;

This step is similar to the 801 part of Figure 8, and will not be described here. It should be noted that the two-step transmission can be understood as an HDM information frame in the "Overall Overview" section. The main difference between the two is that the multiple OTN frame carrying measurement indication information may be the same as the 801 part of FIG. 8, that is, a timestamp information. However, in this embodiment, the information may not be a time stamp, but may be other information. For example, one bit of measurement indication information can be carried. By setting this bit to 1, it indicates that the source node of the delay measurement path is performing delay measurement. It should be noted that although N2 may not carry the information for transmitting the frame in the transmitted OTN frame, N2 must record the time information (for example, save the data in a storage unit), so as to be used for subsequent delay calculation. . It can be understood that the “first timestamp” carries a specific time information. However, the information may also be replaced by "measurement indication information", which is information indicating that the node N2 is performing delay measurement, that is, by one or more bits, indicating that the N2 node has recorded the OTN frame. Send time information. The present invention does not impose any particular limitation on the information format specifically carried in this step.

In section 902, N4 obtains the first timestamp;

Specifically, N4 obtains a timestamp for transmitting the second OTN frame from the received multiple first OTN frames. Alternatively, if the N2 sends the measurement indication information, the N4 obtains the measurement indication information from the multiple first OTN frames, thereby determining that the upstream node is performing the delay measurement.

In section 903, N4 sends a plurality of third OTN frames, the plurality of third OTN frames transmitting the first timestamp, the second timestamp, and the third timestamp; wherein the second timestamp indicates the a time when the N4 receives the second OTN frame, where the third timestamp indicates that the N4 sends the time of the fourth OTN frame corresponding to the second OTN frame in the multiple third OTN frames;

Specifically, N4 transmits the HDM response frame mentioned in the "Overall Overview" section. Optionally, the OTN frame may carry node identification information for verification by the source node to ensure that the received data is from the correct peer node. This method of verification is especially useful in multi-channel DM measurements as described in Example 4.

It should be noted that N4 can directly copy the timestamp or measurement indication information it receives to the HDM response frame that it sends back to N2. For example: if the measurement indication information is time stamp information. Alternatively, N4 may modify the received information to indicate that it has received the information. For example, if the measurement indication information is 1 bit, it can be represented by bit flipping (ie, changing from 1 to 0). For another example, if the measurement is only a plurality of bits of information, it can be represented by adding a value of 1.

In addition, N4 also needs to obtain the second and third timestamps described above. The fourth OTN frame therein can be understood as a response frame sent back to N2 for the second OTN frame by N4. Similar to step 801, the present invention does not impose any restrictions on the location of the second and fourth OTN frames in a set of OTN frames.

In section 904, N2 determines a bidirectional transmission delay between N2 and N4 according to the first timestamp, the second timestamp, the third timestamp, and the time when the N2 frame is received by the N2. .

Supposing that the first timestamp, the second timestamp, the third timestamp, and N2 receive the fourth When the time of the OTN frame corresponds to TxTimeStamp, RxTimeStamp, TxTimeStamp' and RxTime, respectively, the bidirectional transmission delay can be calculated as RxTime-TxTimeStamp-(TxTimeStamp'-RxTimeStamp). Wherein, TxTimeStamp'-RxTimeStamp is the processing time of N4 for receiving an OTN frame containing HDM overhead. It should be noted that if the processing time of the destination node is negligible, the two timestamp information need not be carried in the HDM response frame. Alternatively, instead of carrying two specific timestamps, the time information may be processed by carrying a specific destination node.

It should be noted that the above-mentioned N2 and N4 are only examples, and may be replaced by a common first network device and a second network device, which are used to indicate that the delay measurement requires any two devices on one service path.

The HDM overhead can include control fields depending on the specific needs. If the DM overhead includes a control field, the value of the DMtype field may be 0010 as shown in Table 1. If periodic measurements are required, the DMma field has a value of 0001. If it is only one measurement, it can be set to 0010 as shown in Table 1.

By carrying the delay measurement overhead in the OTN frame, the overhead carries one or more timestamps, and the node can perform high-accuracy delay measurement. This method can support more accurate measurements than existing methods. By carrying the delay measurement overhead in the overhead area of the OTN, the bandwidth of the service data is not occupied, and the network bandwidth utilization is improved.

Example 3:

One embodiment of the present invention provides yet another method, apparatus, and system for time delay measurement in an optical network. This embodiment supports hybrid delay measurement. Specifically, the network device shown in FIG. 1 is taken as an example, and the service path is assumed to be N1-N2-N3-N4-N5, and the delay measurement path is the same as the service path.

The interaction process of N1 and N5 is the same as the interaction process of N2 and N4 in Embodiment 2, and details are not described herein again. The only difference is that while calculating the bidirectional path, N1 can also accurately calculate the one-way delay from N1 to N5 and from N5 to N1 by using the timestamp information contained therein. Specifically, the delay from N1 to N5 can be obtained by RxTimeStamp-TxTimeStamp, and the delay of N5 to N1 can be obtained by RxTime-TxTimeStamp'. It should be noted that the two one-way delays are not necessarily the same, so the respective calculations can improve the accuracy. If the accuracy is not high, for example, RxTimeStamp and TxTimeStamp' are not included in the third OTN frame, and the average one-way delay information can be obtained by dividing the two-way delay calculated in Embodiment 2 by 2. If the third OTN frame carries the processing delay of the second network device, a more accurate one-way delay information can also be obtained by using the two-way delay-processing delay calculated in Embodiment 2/2. .

By carrying the delay measurement overhead in the OTN frame, the overhead carries one or more timestamps, and the node can perform multiple types of delay measurement with high precision at the same time. Compared to existing methods, this method can support many different types of delay measurements and can support more accurate measurements. By carrying the delay measurement overhead in the overhead area of the OTN, the bandwidth of the service data is not occupied, and the network bandwidth utilization is improved.

Example 4:

One embodiment of the present invention provides yet another method, apparatus, and system for time delay measurement in an optical network. Real The example supports delay measurements for multiple different paths or path segments. Specifically, taking the network device shown in FIG. 1 as an example, as shown in FIG. 10, it is assumed that there are three delay measurement paths, specifically: N2-N3-N4, N1-N2-N3-N4-N5, and N1. -N6-N7-N8. Each path measures one-way, two-way, or mixed delay. For specific methods, refer to Embodiment 1-3, and details are not described herein again.

It should be noted that, in order to support the multipath delay measurement, multiple HDM overheads, that is, multiple HDM overheads, need to be carried in the OTN frame. Specifically, more reserved fields (see the frame structure examples of FIGS. 3 and 4 in detail) can be used to carry the HDM overhead. It should also be noted that the number of paths that need to be measured can be determined according to actual needs. If the two paths do not coincide at all, for example, the first and third delay measurement paths described above, they can reuse the same HDM overhead to save the overhead of the OTN frame.

It should also be noted that the network device or the network controller can determine the quantity M that needs to be measured according to the quantity N that needs to be measured, where M is less than or equal to N. That is to say, if the calculation can be performed by simple mathematical operations, the actual number of paths measured can be less than the number of paths to be measured to save network overhead.

By carrying multiple delay measurement overheads in an OTN frame, the overhead carries one or more timestamps, and the nodes can simultaneously perform multi-channel high-precision delay measurement. This method can support more accurate measurements than existing methods.

Example 5:

FIG. 11 is a schematic structural diagram of a possible network device. The network device includes a processing unit 111, a transmitting unit 112, and a receiving unit 113. The processing unit 111 may further include a first processing unit 1111 and a second processing unit 1112. In addition, the sending unit 112 and the receiving unit 113 may also be one transceiver unit.

It should be noted that the network device can be used to implement the network devices with different behaviors mentioned in the foregoing Embodiments 1-4 to achieve the requirement of unused time delay measurement. Some examples will be given below. It should also be noted that the transmitting unit or the receiving unit may be an optional unit.

In a possible implementation, the network device is N4 shown in FIG. 8, which is a destination node network device of a time delay measurement path. Specifically, the processing unit 111 is configured to perform the actions described in section 802 of FIG. The receiving unit is configured to receive an OTN frame sent by the other network device (for example, N3 in FIG. 8) to the network device. Optionally, the first processing unit 1111 is configured to acquire a time when the OTN frame is received and obtain timestamp information carried in the OTN frame. The second processing unit 1112 is configured to calculate a transmission delay.

In another possible implementation, the network device is N1 shown in FIG. 8, that is, a source node network device of a delay measurement path. Specifically, the processing unit 111 is configured to generate an OTN frame. The sending unit is configured to send the OTN frame to another network device (for example, N2 in FIG. 8).

In another possible implementation, the network device is N2 shown in FIG. 9, that is, a source node network device of a delay measurement path. Specifically, the processing unit 111 is configured to perform the actions described in section 904 of FIG. The 111 is also used to generate an OTN frame. The sending unit is configured to send the OTN frame to another network device (for example, N3 in FIG. 9). The receiving unit is configured to receive an OTN frame sent by the other network device (for example, N3 in FIG. 9) to the network device. Optionally, the first processing unit 1111 is configured to generate an OTN frame. The second processing unit is configured to perform the 904 partial action of FIG.

In a further possible implementation, the network device is N4 shown in FIG. 9, which is a destination node network device of a delay measurement path. Specifically, the processing unit 111 is configured to perform the motion described in section 902 of FIG. Work. The receiving unit 113 is configured to receive an OTN frame sent by the other network device (for example, N3 in FIG. 9) to the network device.

It should be noted that the operations performed by the respective units described above are only specific examples, and the actions actually performed by the respective units refer to the actions/steps mentioned in the description of the above embodiments 1-4. It should also be noted that the units may be located in the circuit board and/or the tributary board in the OTN hardware structure diagram described in FIG. 2. The present invention does not impose any limitation on the position of the board in which the respective units are specifically described.

It should also be noted that the above processing unit, transmitting unit, receiving unit and transceiving unit may also be replaced by a processor, a transmitter, a receiver and a transceiver. It should also be noted that the OTN frame structure employed by the device or node is the various frame structures described in the "Overall Overview" section. The design of the specific frame structure can be differently selected according to needs, and the present invention does not impose any limitation on this.

A person skilled in the art may understand that all or part of the steps of implementing the above embodiments may be completed by hardware, or may be instructed by a program to execute related hardware, and the program may be stored in a computer readable storage medium. The storage medium mentioned may be a read only memory, a random access memory or the like. Specifically, for example, the processing unit or processor may be a central processing unit, a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device. , transistor logic, hardware components, or any combination thereof. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods for implementing the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present invention.

When implemented in software, the method steps described in the above embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in accordance with embodiments of the present invention are generated in whole or in part. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer readable storage medium or transferred from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be from a website site, computer, server or data center Transfer to another website site, computer, server, or data center by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL), or wireless (eg, infrared, wireless, microwave, etc.). The computer readable storage medium can be any available media that can be accessed by a computer or a data storage device such as a server, data center, or the like that includes one or more available media. The usable medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (such as a solid state disk (SSD)).

Finally, it should be noted that the above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, and any person skilled in the art can easily within the technical scope disclosed by the present invention. Any changes or substitutions are contemplated as being within the scope of the invention. Therefore, the scope of the invention should be determined by the scope of the appended claims.

Claims

A method for measuring a time delay in an optical network, the method comprising:

Receiving, by the first network device, a plurality of optical transport network (OTN) frames sent by the second network device, where an overhead area of each of the plurality of OTN frames carries a delay measurement overhead, and the overhead of the multiple OTN frames The time delay measurement overhead carried by the area carries a timestamp indicating the time when the second network device sends the first OTN frame in the multiple OTN frames;

The first network device determines a transmission delay of the second network device to the first network device according to the timestamp and a time when the first network device receives the first OTN frame.
The method of claim 1 wherein said delay measurement overhead is delimited based on a multiframe alignment signal (MFAS) included in said plurality of OTN frames to obtain said time stamp.
The method according to claim 1 or 2, wherein each of the OTN frames is an optical transmission unit k (OTUk) frame, an n*100G optical transmission unit (OTUCn) frame or a flexible OTN (FlexO) frame.
The method according to any one of claims 1-3, wherein the overhead area of each OTN frame is an overhead area of an optical transmission unit k (OTUk) frame, or an optical data unit k included in an OTUk frame ( The overhead area of the ODUk) or the overhead area of the optical payload unit k (OPUk) included in the OTUk frame; or the overhead area of the OTN frame is the overhead of the optical transmission unit (OTUCn) frame of n*100G The area, or the overhead area of the optical data unit (ODUCn) of the n*100G included in the OTUCn frame; or the overhead area of each OTN frame is the overhead area of the flexible OTN (FlexO) frame.
The method according to any one of claims 1-4, wherein a delay measurement overhead carried by an overhead area of the plurality of OTN frames transmits a node identifier of the first network device and the second network device information.
The method of claim 5, the node identification information being a Path Trace Identity (TTI), an Internet Protocol (IP) address, or a Medium Access Control (MAC) address.
An optical network device, characterized in that the device comprises a processor and a transceiver, wherein:

The transceiver is configured to receive a plurality of optical transport network (OTN) frames sent by another network device, where an overhead region of each of the plurality of OTN frames carries a delay measurement overhead, and the multiple OTN frames The time delay measurement overhead carried by the overhead area carries a timestamp indicating the time at which the another network device sends the first OTN frame in the multiple OTN frames;

The processor is configured to determine, according to the timestamp and a time when the device receives the first OTN frame, a transmission delay of the another network device to the device.
The apparatus of claim 7, wherein the processor delimits the latency measurement overhead based on a multiframe alignment signal (MFAS) included in the plurality of OTN frames to obtain the timestamp.
The apparatus according to claim 7 or 8, wherein each of said OTN frames is an optical transmission unit k (OTUk) frame, an n*100G optical transmission unit (OTUCn) frame or a flexible OTN (FlexO) frame.
The device according to any one of claims 7-9, wherein the overhead area of each OTN frame is an overhead area of an optical transmission unit k (OTUk) frame, or an optical data unit k included in the OTUk frame ( The overhead area of the ODUk) or the overhead area of the optical payload unit k (OPUk) included in the OTUk frame; or the overhead area of the OTN frame is the overhead of the optical transmission unit (OTUCn) frame of n*100G The area, or the overhead area of the optical data unit (ODUCn) of the n*100G included in the OTUCn frame; or the overhead area of each OTN frame is the overhead area of the flexible OTN (FlexO) frame.
The device according to any one of claims 7 to 10, wherein the delay measurement overhead carried by the overhead area of the plurality of OTN frames conveys node identification information of the device and the another network device.
The apparatus of claim 11, the node identification information being a Path Trace Identity (TTI), an Internet Protocol (IP) address, or a Medium Access Control (MAC) address.
A method for measuring a time delay in an optical network, the method comprising:

The first network device sends a plurality of first optical transport network (OTN) frames to the second network device, where an overhead region of each of the plurality of first OTN frames carries a delay measurement overhead, where the plurality of first The time delay measurement overhead carried in the overhead area of the OTN frame transmits a first timestamp, where the first timestamp indicates a time when the first network device sends the second OTN frame in the multiple first OTN frames;

Receiving, by the first network device, a plurality of third OTN frames from the second network device, where the plurality of third OTN frames deliver the first timestamp;

And the first network device determines, according to the first timestamp, a time when the first network device receives the fourth OTN frame corresponding to the second OTN frame in the multiple third OTN frames A two-way transmission delay between the first network device and the second network device.
The method of claim 13, wherein the plurality of third OTN frames further pass a second timestamp and a third timestamp, the second timestamp indicating that the second network device receives the a time of the second OTN frame, the third timestamp indicating a time when the second network device sends the fourth OTN frame, the method further includes:

The bidirectional transmission delay is modified according to the second timestamp and the third timestamp.
The method according to claim 13 or 14, wherein the delay measurement overhead is delimited according to a multiframe alignment signal (MFAS) included in the plurality of first OTN frames to obtain the first timestamp. .
The method according to any one of claims 13-15, wherein each of the first OTN frame and each of the third OTN frames is an optical transmission unit k (OTUk) frame and an optical transmission of n*100G Unit (OTUCn) frame or flexible OTN (FlexO) frame.
The method according to any one of claims 13-16, wherein an overhead area of each of the first OTN frame and each of the third OTN frames is an overhead area of an optical transmission unit k (OTUk) frame, Or an overhead area of the optical data unit k (ODUk) included in the OTUk frame, or an overhead area of the optical payload unit k (OPUk) included in the OTUk frame; or each of the first OTN frames and the The overhead area of each third OTN frame is an overhead area of an optical transmission unit (OTUCn) frame of n*100G, or an overhead area of an optical data unit (ODUCn) of n*100G included in the OTUCn frame; or, each of the above The overhead area of a first OTN frame and each of the third OTN frames is an overhead area of a flexible OTN (FlexO) frame.
The method according to any one of claims 13-17, wherein the delay measurement overhead carried by the overhead regions of the plurality of first OTN frames is transmitted by the first network device and the second network device Node identification information.
The method of claim 18, the node identification information being a Path Trace Identity (TTI), an Internet Protocol (IP) address, or a Medium Access Control (MAC) address.
The method of any of claims 13 to 19, further comprising:

Determining, by the first network device, a transmission delay of the first network device to the second network device according to the first timestamp and a time when the first network device receives the fourth OTN frame At least one of a transmission delay of the second network device to the first network device.
An optical network device, characterized in that the device comprises a processor and a transceiver, wherein:

The transceiver is configured to send a plurality of first optical transport network (OTN) frames to another network device, where an overhead area of each of the plurality of first OTN frames carries a delay measurement overhead, where the The time delay measurement overhead carried by the overhead area of the first OTN frame transmits a first timestamp, where the first timestamp indicates a time when the device sends the second OTN frame in the multiple first OTN frames;

The transceiver is further configured to receive a plurality of third OTN frames sent by the another network device, where the multiple third OTN frames deliver the first timestamp;

The processor is configured to determine, according to the first timestamp, a time when the device receives the fourth OTN frame corresponding to the second OTN frame in the multiple third OTN frames, The two-way transmission delay between the other network devices.
The device according to claim 21, wherein the plurality of third OTN frames further pass a second timestamp and a third timestamp, the second timestamp indicating that the another network device receives the second timestamp The time of the OTN frame, the third timestamp indicating the time when the another network device sends the fourth OTN frame, the method further includes:

The bidirectional transmission delay is modified according to the second timestamp and the third timestamp.
The apparatus according to claim 22, wherein said processor delimits a delay measurement overhead according to a multiframe alignment signal (MFAS) included in said plurality of first OTN frames to obtain said first time stamp.
The device according to any one of claims 21-23, wherein each of the first OTN frame and each of the third OTN frames is an optical transmission unit k (OTUk) frame and an optical transmission of n*100G Unit (OTUCn) frame or flexible OTN (FlexO) frame.
The device according to any one of claims 22-24, wherein an overhead area of each of the first OTN frame and each of the third OTN frames is an overhead area of an optical transmission unit k (OTUk) frame, Or an overhead area of the optical data unit k (ODUk) included in the OTUk frame, or an overhead area of the optical payload unit k (OPUk) included in the OTUk frame; or, each of the first OTN frames and The overhead area of each third OTN frame is an overhead area of an optical transmission unit (OTUCn) frame of n*100G, or an overhead area of an optical data unit (ODUCn) of n*100G included in the OTUCn frame; or The overhead area of each of the first OTN frame and each of the third OTN frames is an overhead area of a flexible OTN (FlexO) frame.
The device according to any one of claims 21-25, wherein the delay measurement overhead carried by the overhead regions of the plurality of first OTN frames transmits node identification information of the device and the another network device .
The method of claim 26, the node identification information being a Path Trace Identity (TTI), an Internet Protocol (IP) address, or a Medium Access Control (MAC) address.
The device according to any one of claims 21 to 27, wherein the processor is further configured to:

Determining, according to the first timestamp and a time when the device receives the fourth OTN frame, a transmission delay of the another network device to the device and a transmission of the device to the another network device At least one of the delays.
An optical transport network (OTN) frame structure, wherein the frame structure comprises a fixed frame area, an optical transmission unit OTU overhead, an optical data unit ODU overhead, an optical payload unit OPU overhead, an OPU payload area, and a forward direction Error correcting the FEC area, the ODU overhead including a delay measurement overhead; or the frame structure includes a fixed frame area, a flexible OTN (FlexO) overhead area, a FlexO payload area, and an FEC area, the FlexO overhead area including the Delay measurement overhead; where:

The delay measurement overhead carries partial information of at least one timestamp, the at least one timestamp being used to support delay measurement between two devices using the OTN frame structure.
The frame structure of claim 29, the frame structure further comprising a multiframe alignment signal (MFAS), the frame structure delimiting the latency measurement overhead with the MFAS field to obtain the at least one Timestamp.
The frame structure according to claim 29 or 30, wherein the delay measurement overhead further carries node identification information of the two devices.
The frame structure of any of claims 31, wherein the node identification information is a Path Trace Identity (TTI), an Internet Protocol (IP) address, or a Medium Access Control (MAC) address.