WO2017097034A1

WO2017097034A1 - Time stamp processing method and apparatus for time message in optical transport network

Info

Publication number: WO2017097034A1
Application number: PCT/CN2016/102279
Authority: WO
Inventors: 陈宗正
Original assignee: 深圳市中兴微电子技术有限公司
Priority date: 2015-12-09
Filing date: 2016-10-17
Publication date: 2017-06-15
Also published as: CN106856422A; CN106856422B

Abstract

Disclosed is a time stamp processing method for a time message in an optical transport network, comprising: determining time of a message header of a time message and a corresponding first multi-frame number according to a frame header and a multi-frame number of an optical transport network (OTN) frame; acquiring a second multi-frame number corresponding to a message header of a time message, subjected to forward error correction (FEC) decoding or coding, of the OTN frame; obtaining a difference between the first multi-frame number and the second multi-frame number according to a difference calculation rule; and obtaining a final time stamp of the time message according to the time of the message header of the time message and the difference, obtained according to the difference calculation rule, between the first multi-frame number and the second multi-frame number. Also disclosed is a time stamp processing apparatus for a time message in an optical transport network.

Description

Time stamp processing method and device for time message in optical transmission network

Technical field

The present invention relates to a transmission technology of an optical transmission network, and in particular, to a method and an apparatus for processing a time stamp of a time packet in an optical transmission network.

Background technique

With the development of communication networks, optical transport networks (OTNs) have become the mainstream of transmission networks. Various services are carried by OTN networks. Therefore, OTN networks must be able to provide high-precision network reference clocks to meet the network. The synchronization requirements of the node or terminal.

In the prior art, the time processing device of the OTN network is used to process the time message to implement the time transmission. Due to the time requirement, in the direction that the time message enters the time processing device, the time message needs to be obtained. The time stamp of the time processing device, in the direction of the time message out of the time processing device, it is necessary to obtain the time stamp when the time message is sent to the time processing device, and the sampling and processing of the time stamp is an indispensable part. In the OTN network, the OTN frame undergoes processing such as cross-clock domain, framing, Forward Error Correction (FEC) codec, and the like, in particular, each frame reset of the FEC codec brings different frame delays. The time stamp that causes the sampling may have a large deviation, which ultimately affects the accuracy of the time.

Summary of the invention

In view of this, the embodiments of the present invention are directed to a method and a device for processing a time stamp of a time packet in an optical transmission network, so as to eliminate a frame delay caused by an abnormal reset of the FEC codec and reduce the sampling time. The time stamp of the message can obtain the time stamp of the accurate time message.

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

The embodiment of the invention provides a time stamp processing method for a time packet in an optical transmission network, and the method includes:

Determining, according to a frame header and a multiframe number of the OTN frame of the optical transmission network, a time of the packet header of the time packet and a corresponding first multiframe number;

Acquiring a second multiframe number corresponding to a packet header of the time packet after the forward error correction FEC decoding or encoding of the OTN frame;

Obtaining a difference between the first multiframe number and the second multiframe number according to a difference calculation rule;

Obtaining a difference between the first multiframe number and the second multiframe number according to the time of the packet header of the time packet and the difference calculation rule, to obtain a time stamp of the final time packet.

In the above method, the difference between the first multiframe number and the second multiframe number is obtained according to the difference calculation rule, and specifically includes:

After the OTN frame is FEC-decoded, it is determined whether the first multi-frame number is greater than or equal to the second multi-frame number, and if the first multi-frame number is greater than or equal to the second multi-frame number, Directly calculating a difference between the first multiframe number and the second multiframe number;

If the first multiframe number is smaller than the second multiframe number, the difference between the first multiframe number and the second multiframe number is calculated by adding 256 to the first multiframe number.

In the above method, the difference between the first multiframe number and the second multiframe number is obtained according to the time of the packet header of the time packet and the difference calculation rule, to obtain a final time. Time stamp of the message, including:

Subtracting the time of the packet header of the time packet by the product of the difference between the first multiframe number and the second multiframe number and the transmission time of the single OTN frame, to obtain the final time packet. Time stamp

The time stamp of the final time message is an entry time stamp.

After the OTN frame is FEC-encoded, it is determined whether the first multi-frame number is small. And equal to the second multiple frame number, if the first multiple frame number is less than or equal to the second multiple frame number, directly calculating a difference between the first multiple frame number and the second multiple frame number;

If the first multiframe number is greater than the second multiframe number, the second multiframe number is added to 256 and then the difference from the first multiframe number is calculated.

Adding the time of the packet header of the time packet to the product of the difference between the first multiframe number and the second multiframe number and the transmission time of the single OTN frame, to obtain the final time packet. Time stamp

The time stamp of the final time message is a time stamp.

In the above method, before the determining the time of the packet header of the time packet and the corresponding first multiframe number according to the frame header and the multiframe number of the OTN frame of the optical transmission network, the method further includes:

The time at which the message header is generated;

In the above method, after the time stamp of the final time message is obtained, the method further includes:

Adding the timestamp of the last time message to the source timestamp field of the time message, or adding the timestamp of the final time message to the correction field of the time message.

The embodiment of the invention further provides a time stamp processing device for a time message in an optical transmission network, the device comprising:

a determining module, configured to determine, according to a frame header and a multiframe number of the OTN frame of the optical transmission network, a time of the packet header of the time packet and a corresponding first multiframe number;

An acquiring module, configured to acquire a second multiframe number corresponding to a packet header of a time packet after the forward error correction FEC decoding or encoding of the OTN frame;

a difference calculation module, configured to obtain a difference between the first multiframe number and the second multiframe number according to a difference calculation rule;

The time stamp calculation module is configured to obtain a difference between the first multiframe number and the second multiframe number according to the time of the packet header of the time packet and the difference calculation rule, to obtain a final Time stamp of the time message.

In the above apparatus, the difference calculation module is further configured to: if the OTN frame is FEC-decoded, determine whether the first multi-frame number is greater than or equal to the second multi-frame number, if the If a multi-frame number is greater than or equal to the second multi-frame number, directly calculating a difference between the first multi-frame number and the second multi-frame number;

In the above apparatus, the time stamp calculation module is further configured to subtract the difference between the first multiframe number and the second multiframe number and a single OTN frame by the time of the packet header of the time packet. Transmitting a product of time to obtain a time stamp of the final time message;

The time stamp of the final time message is an entry time stamp.

In the above apparatus, the difference calculation module is further configured to determine, when the OTN frame is FEC-encoded, whether the first multi-frame number is less than or equal to the second multi-frame number, if the If a multi-frame number is less than or equal to the second multi-frame number, directly calculating a difference between the first multi-frame number and the second multi-frame number;

In the above apparatus, the time stamp calculation module is further configured to add a time of the packet header of the time packet to a difference between the first multiframe number and the second multiframe number and a single OTN frame. Transmitting a product of time to obtain a time stamp of the final time message;

The time stamp of the final time message is a time stamp.

In the above device, the device further includes:

A time module configured to generate the time of the message header.

In the above device, the device further includes:

a timestamp processing module, configured to add a timestamp of the last time message to a source timestamp field of the time message, or configured to add a timestamp of the final time message to the timestamp The revised domain of the text.

The determining module, the obtaining module, the difference calculating module, the time stamp calculating module, and the time module may use a central processing unit (CPU) and a digital signal processor when performing processing. (DSP, Digital Singnal Processor) or Programmable Array (FPGA) implementation.

The method and device for processing a time stamp of a time packet in an optical transmission network according to an embodiment of the present invention first determines the time of the packet header of the time packet and the corresponding first by determining the frame header and the multiframe number of the OTN frame. The second multi-frame number corresponding to the header of the time packet of the OTN frame after the forward error correction FEC decoding or encoding; and then obtaining the first multiframe number and the second complex according to the difference calculation rule The difference of the frame number; finally, according to the time of the packet header of the time packet and the difference between the first multiframe number and the second multiframe number according to the difference calculation rule, the time stamp of the final time packet is obtained, that is, The time stamp at the entrance or the exit of the processing device of the time stamp of the time message in the optical transmission network can be obtained; the frame delay caused by the FEC encoding or decoding each abnormal reset is eliminated, and the frame delay is reduced. The time stamp of the sampling time message can obtain the time stamp of the accurate time message.

DRAWINGS

1 is a flowchart of an embodiment of a method for processing a time stamp of a time packet in an optical transmission network according to the present invention;

2 is a schematic structural diagram of an embodiment of a device for processing a time stamp of a time packet in an optical transmission network according to the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described in the following with reference to the accompanying drawings.

1 is a flowchart of an embodiment of a method for processing a time stamp of a time packet in an optical transmission network according to the present invention. As shown in FIG. 1, the method of the present invention may include the following steps:

Step 101: Generate a local time required for the time message.

The time module of the processing device for the time stamp of the time packet in the optical transmission network (hereinafter referred to as the processing device) is mainly used for generating the local time for the subsequent time packet, the packet header of the time packet and the OTN frame; The time module uses the local clock to count and accumulates at a fixed step value to generate an 80-bit time. The upper 48 bits are the whole second part, and the lower 32 bits are the nanosecond part. When the low 32-bit nanosecond part is added to the 1 second time, , enter 1 to the high.

Step 102: Determine, according to a frame header and a multiframe number of the OTN frame of the optical transmission network, a time of the packet header of the time packet and a corresponding first multiframe number.

Since the OTN network uses a certain reserved overhead in the OTN frame to transmit the time message, and each OTN frame transmits only one byte of the time message, the time at the frame header of the OTN frame can be sampled as a time report. The time of the text, that is, the processing device first acquires the frame header and the multiframe number of the OTN frame, and then determines the header of the time packet that has not been FEC decoded according to the frame header and the multiframe number of the obtained OTN frame. The time and the corresponding multiframe number are defined as the first multiframe number, represented by M1, and the time of the header is represented by T2.

Step 103: Acquire a second multiframe number corresponding to a packet header of a time packet in which the OTN frame is subjected to forward error correction FEC decoding or encoding.

The processing device obtains the multi-frame number corresponding to the header of the time packet from the reserved overhead of the OTN frame after FEC decoding or encoding, and the multi-frame number is defined as the second multi-frame number, which is represented by M2.

Step 104: Obtain a difference between the first multiframe number and the second multiframe number according to a difference calculation rule.

After acquiring the first multi-frame number M1 and the second multi-frame number M2, the processing device can obtain the difference between the two according to the difference calculation rule, wherein the difference calculation rule is divided into OTN frames after FEC decoding (time report) The text enters the direction) and the OTN frame is subjected to FEC encoding (time message outgoing direction). The specific conditions are as follows:

When the OTN frame is subjected to FEC decoding (time message entering direction), the processing device determines whether the first multiframe number M1 is greater than or equal to the second multiframe number M2, if the first multiframe number M1 is greater than or equal to the second The complex frame number M2 directly calculates the M2 difference D of the first multiple frame number M1 and the second multiple frame number, that is, D=M1-M2; if the first multiple frame number M1 is smaller than the second multiple frame number M2, After the first multiframe number M1 is added to 256, the difference D from the second multiframe number M2 is calculated, that is, D=M1+256-M2.

After the OTN frame is FEC-encoded, the processing device determines whether the first multi-frame number M1 is less than or equal to the second multi-frame number M2, and directly calculates if the first multi-frame number M1 is less than or equal to the second multi-frame number M2. The difference D between the first multiple frame number M1 and the second multiple frame number M2, that is, D=M2-M1; if the first multiple frame number M1 is greater than the second multiple frame number M2, the second multiple frame number M2 is added to 256. Then calculate the difference D from the first multiframe number M1, that is, D=M2+256-M1.

Step 105: Obtain a difference between the first multiframe number and the second multiframe number according to the packet header time of the time packet and the difference calculation rule, to obtain a final time packet. stamp.

After the OTN frame is subjected to FEC decoding (time packet entering direction), the processing device subtracts the difference D between the first complex frame number M1 and the second complex frame number M2 from the time T2 of the packet header of the time message. The product of the single OTN frame transmission time Ct is obtained as the time stamp Ti of the final time message, that is, Ti=T2-D*Ct; the time stamp Ti of the final time message is the time stamp of the time message.

After the OTN frame is subjected to FEC encoding (time message outgoing direction), the processing device adds the time T2 of the packet header of the time packet to the difference D between the first multiframe number M1 and the second complex frame number M2. The time stamp To of the final time message is obtained by the product of the single OTN frame transmission time Ct, that is, To=T2+D*Ct; the time stamp Ti of the final time message is the time stamp of the time message.

Wherein, since the rate of the OTN frame is fixed, the time required to transmit a single OTN frame is also fixed, and the time for transmitting a single OTN frame is defined as Ct.

Step 106: Add a timestamp of the final time packet to a source timestamp field of the time message or a modified field of the time message.

The processing device adds the time stamp of the final time packet to the source time stamp domain of the time packet, or adds the time stamp of the final time packet to the correction domain of the time packet, and performs subsequent processing.

The processing method of the time stamp of the time packet in the optical transmission network provided by the embodiment of the present invention, the processing device for the time stamp of the time packet in the optical transmission network first determines the time packet according to the frame header and the multiframe number of the OTN frame. The time of the packet header and the corresponding first multiframe number; secondly, the second multiframe number corresponding to the header of the time packet of the OTN frame subjected to the forward error correction FEC decoding or encoding; and then calculated according to the difference The rule obtains a difference between the first multiframe number and the second multiframe number; and finally obtains a difference between the first multiframe number and the second multiframe number according to the time of the packet header of the time packet and the difference calculation rule. Obtaining the time stamp of the final time message, that is, the time stamp at the entrance or the exit of the processing device of the time stamp of the time message in the optical transmission network; eliminating the FEC encoding or decoding each abnormal reset The frame delay brought by the time frame reduces the time stamp deviation of the sampling time message, and can obtain the accurate time stamp of the time message.

2 is a schematic structural diagram of an apparatus for processing a time stamp of a time packet in an optical transmission network according to the present invention. As shown in FIG. 2, the processing apparatus 02 for time stamping of a time packet in the optical transmission network includes: a determining module 21 , the obtaining module 22, the difference calculating module 23, and the time stamp calculating module 24; wherein

The determining module 21 is configured to determine, according to a frame header and a multiple frame number of the OTN frame of the optical transmission network, a time of the packet header of the time packet and a corresponding first multiple frame number;

The acquiring module 22 is configured to acquire a second multi-frame number corresponding to a packet header of a time packet in which the OTN frame is subjected to forward error correction FEC decoding or encoding;

The difference calculation module 23 is configured to obtain a difference between the first multiframe number and the second multiframe number according to a difference calculation rule;

The timestamp calculation module 24 is configured to obtain a difference between the first multiframe number and the second multiframe number according to the time of the packet header of the time packet and the difference calculation rule. Get the time stamp of the final time message.

In an embodiment of the present invention, the difference calculation module 23 is configured to determine, when the OTN frame is FEC-decoded, whether the first multi-frame number is greater than or equal to the second complex. a frame number, if the first multiframe number is greater than or equal to the second multiframe number, directly calculating a difference between the first multiframe number and the second multiframe number;

In an embodiment of the present invention, the timestamp calculation module 24 is specifically configured to subtract the first multiframe number and the second multiple frame number from the time of the packet header of the time packet. The product of the difference between the difference and the transmission time of the single OTN frame, and the time stamp of the final time message is obtained;

The time stamp of the final time message is an entry time stamp.

In an embodiment of the present invention, the difference calculation module 23 is further configured to determine, when the OTN frame is FEC-encoded, whether the first multi-frame number is less than or equal to the second. a multi-frame number, if the first multi-frame number is less than or equal to the second multi-frame number, directly calculating a difference between the first multi-frame number and the second multi-frame number;

In an embodiment of the present invention, the time stamp calculation module 24 is further configured to add the time of the packet header of the time packet to the first multiframe number and the second multiframe. The product of the difference between the number and the transmission time of the single OTN frame, and the time stamp of the final time message is obtained;

The time stamp of the final time message is a time stamp.

In an embodiment of the present invention, the apparatus further includes:

The time module 25 is configured to generate the time of the message header.

In an embodiment of the present invention, the apparatus further includes:

The timestamp processing module 26 is configured to add the timestamp of the final time message to the source timestamp field of the time message, or configured to add the timestamp of the final time message to the timestamp The revised field of the message.

The device in this embodiment may be used to implement the technical solution of the foregoing method embodiment, and the implementation principle and the technical effect are similar, and details are not described herein again.

In an actual application, the determining module 21, the obtaining module 22, the difference calculating module 23, the time stamp calculating module 24, the time module 25, and the time stamp processing module 26 may be processed by a central processing unit (CPU) located on the device. Device (MPU), digital signal processor (DSP) or field programmable gate array (FPGA) implementation.

Those skilled in the art will appreciate that embodiments of the present invention can be provided as a method, system, or computer program product. Accordingly, the present invention can take the form of a hardware embodiment, a software embodiment, or a combination of software and hardware. Moreover, the invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) including computer usable program code.

The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (system), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or FIG. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. Means for implementing the functions specified in one or more of the flow or in a block or blocks of the flow chart.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the computer is readable and stored The instructions in the reservoir produce an article of manufacture comprising an instruction device that implements the functions specified in one or more blocks of the flow or in a flow or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device. The instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

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

Claims

A time stamp processing method for time packets in an optical transmission network, the method comprising:

Determining, according to a frame header and a multiframe number of the OTN frame of the optical transmission network, a time of the packet header of the time packet and a corresponding first multiframe number;

Acquiring a second multiframe number corresponding to a packet header of the time packet after the forward error correction FEC decoding or encoding of the OTN frame;

Obtaining a difference between the first multiframe number and the second multiframe number according to a difference calculation rule;

Obtaining a difference between the first multiframe number and the second multiframe number according to the time of the packet header of the time packet and the difference calculation rule, to obtain a time stamp of the final time packet.
The method according to claim 1, wherein the obtaining the difference between the first multiframe number and the second multiframe number according to the difference calculation rule comprises:

After the OTN frame is FEC-decoded, it is determined whether the first multi-frame number is greater than or equal to the second multi-frame number, and if the first multi-frame number is greater than or equal to the second multi-frame number, Directly calculating a difference between the first multiframe number and the second multiframe number;

If the first multiframe number is smaller than the second multiframe number, the difference between the first multiframe number and the second multiframe number is calculated by adding 256 to the first multiframe number.
The method according to claim 2, wherein said obtaining a first multiframe number and said second multiframe number according to a time of a message header of said time message and said difference calculation rule The difference, the time stamp of the final time message, including:

Subtracting the time of the packet header of the time packet by the product of the difference between the first multiframe number and the second multiframe number and the transmission time of the single OTN frame, to obtain the final time packet. Time stamp

The time stamp of the final time message is an entry time stamp.
The method according to claim 1, wherein the obtaining the difference between the first multiframe number and the second multiframe number according to the difference calculation rule comprises:

After the OTN frame is FEC-encoded, it is determined whether the first multi-frame number is small. And equal to the second multiple frame number, if the first multiple frame number is less than or equal to the second multiple frame number, directly calculating a difference between the first multiple frame number and the second multiple frame number;

If the first multiframe number is greater than the second multiframe number, the second multiframe number is added to 256 and then the difference from the first multiframe number is calculated.
The method according to claim 4, wherein said obtaining a first multiframe number and said second multiframe number according to a time of a message header of said time message and said difference calculation rule The difference, the time stamp of the final time message, including:

Adding the time of the packet header of the time packet to the product of the difference between the first multiframe number and the second multiframe number and the transmission time of the single OTN frame, to obtain the final time packet. Time stamp

The time stamp of the final time message is a time stamp.
The method according to any one of claims 1 to 5, wherein the time of the packet header of the time packet and the corresponding first multiframe are determined according to the frame header and the multiframe number of the OTN frame of the optical transmission network Before the number, the method further includes:

The time at which the message header is generated;
The method according to any one of claims 1 to 5, wherein after the time stamp of the final time message is obtained, the method further comprises:

Adding the timestamp of the last time message to the source timestamp field of the time message, or adding the timestamp of the final time message to the correction field of the time message.
A time stamp processing device for a time message in an optical transmission network, the device comprising:

a determining module, configured to determine, according to a frame header and a multiframe number of the OTN frame of the optical transmission network, a time of the packet header of the time packet and a corresponding first multiframe number;

An acquiring module, configured to acquire a second multiframe number corresponding to a packet header of a time packet after the forward error correction FEC decoding or encoding of the OTN frame;

a difference calculation module, configured to obtain a difference between the first multiframe number and the second multiframe number according to a difference calculation rule;

The time stamp calculation module is configured to obtain a difference between the first multiframe number and the second multiframe number according to the time of the packet header of the time packet and the difference calculation rule, to obtain a final Time stamp of the time message.
The apparatus according to claim 8, wherein the difference calculation module is further configured to determine whether the first multiframe number is greater than or equal to the second complex if the OTN frame is FEC decoded. a frame number, if the first multiframe number is greater than or equal to the second multiframe number, directly calculating a difference between the first multiframe number and the second multiframe number;

If the first multiframe number is smaller than the second multiframe number, the difference between the first multiframe number and the second multiframe number is calculated by adding 256 to the first multiframe number.
The apparatus according to claim 9, wherein the time stamp calculation module is further configured to subtract the first multiframe number and the second multiframe number from a time of a packet header of the time packet The product of the difference between the difference and the transmission time of the single OTN frame, and the time stamp of the final time message is obtained;

The time stamp of the final time message is an entry time stamp.
The apparatus according to claim 8, wherein the difference calculation module is further configured to determine, when the OTN frame is FEC-encoded, whether the first multi-frame number is less than or equal to the second complex a frame number, if the first multi-frame number is less than or equal to the second multi-frame number, directly calculating a difference between the first multi-frame number and the second multi-frame number;

If the first multiframe number is greater than the second multiframe number, the second multiframe number is added to 256 and then the difference from the first multiframe number is calculated.
The apparatus according to claim 11, wherein the time stamp calculation module is further configured to add a time of a message header of the time message to the first multiframe number and the second multiframe number The product of the difference between the difference and the transmission time of the single OTN frame, and the time stamp of the final time message is obtained;

The time stamp of the final time message is a time stamp.
The device according to any one of claims 8 to 12, wherein the device further comprises:

A time module configured to generate the time of the message header.
The device according to any one of claims 8 to 12, wherein the device further comprises:

a timestamp processing module, configured to add a timestamp of the last time message to a source timestamp field of the time message, or configured to add a timestamp of the final time message to the timestamp The revised domain of the text.