WO2017012486A1 - 一种otn网元设备、otn时钟和时间的同步方法及系统 - Google Patents

一种otn网元设备、otn时钟和时间的同步方法及系统 Download PDF

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Publication number
WO2017012486A1
WO2017012486A1 PCT/CN2016/089685 CN2016089685W WO2017012486A1 WO 2017012486 A1 WO2017012486 A1 WO 2017012486A1 CN 2016089685 W CN2016089685 W CN 2016089685W WO 2017012486 A1 WO2017012486 A1 WO 2017012486A1
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Prior art keywords
clock
time
information
network element
element device
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PCT/CN2016/089685
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English (en)
French (fr)
Inventor
陈阳
段呈昕
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中兴通讯股份有限公司
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements

Definitions

  • This document relates to, but is not limited to, the field of network communication technologies, and in particular, to an optical transport network (OTN, optical transport network) network element device, an OTN clock and time synchronization method and system.
  • OTN optical transport network
  • OTN is also commonly known as OTH (Optical Transport Hierarchy) and is a new generation optical transmission system specified by the recommendations of a series of international telecommunication alliance telecommunication standardization organizations such as G.872, G.709, and G.798.
  • OTN combines the advantages of SDH (Synchronous Digital Hierarchy) and WDM (Wavelength Division Multiplexing) bandwidth scalability, integrating transmission and switching capabilities, representing the development direction of next-generation transport networks. .
  • the clock/time signal transmission scheme has two main types, one is in-band transmission, and the in-band transmission scheme includes transmitting 1588 information (such as a clock frequency) and a clock SSM (Synchronization Status Message) through a service signal; The other is an out-of-band transmission.
  • 1588 information such as a clock frequency
  • SSM Synchronization Status Message
  • the out-of-band transmission scheme includes an SSM that transmits 1588 information and a clock through an external channel in the OTN network.
  • the network element device in the OTN in the related art generally supports only one clock/time signal.
  • the transmission mode that is, the network element device in the OTN cannot simultaneously support in-band transmission and out-band transmission, and cannot fully utilize the network element device in the OTN in the related technology to transmit clock and time information.
  • the embodiment of the invention provides an OTN network element device, an OTN clock and time synchronization method and system, which can transmit clock and time information by using the network element device in the OTN.
  • An optical transmission network (OTN) network element device provided by the embodiment of the present invention includes: a time clock extraction module, a time clock processing module, and a time clock transmission module, where the time clock processing module passes a dedicated time The clock channel is respectively connected to the time clock extraction module and the time clock transmission module.
  • the time clock extraction module is configured to determine a time clock transmission scheme according to a link type of the network where the OTN network element device is located, and extract time information from a service port and/or a panel interface corresponding to the time clock transmission scheme. And clock information, and the extracted time information and clock information are sent to the time clock processing module via a dedicated time clock channel;
  • the time clock processing module is configured to: when receiving the clock information, complete clock synchronization of the OTN network element device according to the received clock information; and when receiving the time information, calibrate the time according to the received time information The time of the OTN network element device; and sending the processed clock information and time information to the time clock transmission module via a dedicated time clock channel;
  • the time clock transmission module includes an in-band transmission channel and an out-band transmission channel, and is set to a time clock transmission scheme determined according to the time clock extraction module, and the in-band transmission channel or the out-band transmission channel is selected to be processed by the time clock processing module.
  • the subsequent time information and clock information are transmitted to the next-level OTN network element device.
  • the time clock extraction module includes a clock extraction unit and a time extraction unit.
  • the clock extraction unit is configured to extract a clock frequency and synchronization state information SSM from a service signal transmitted from a service port, or extract a clock frequency and an SSM from a signal transmitted by the panel clock source interface, and extract the extracted clock frequency and the SSM Transmitting, as the clock information, to the time clock processing module;
  • the time extracting unit is configured to extract a precise time protocol PTP message or a second pulse 1PPS and a daily time constant TOD message from the service port and/or the panel interface, and use the extracted PTP message or the 1PPS and TOD message as Time information is transmitted to the time clock processing module.
  • the time extraction unit is set to:
  • the OTN network element device When the extracted packet includes a PTP packet, if the OTN network element device is the master node device, the timestamp of the OTN network element device is added to the extracted PTP packet, and the timestamp PTP is added. Sending the message as the time information to the time clock processing module; if the OTN The network element device is a slave node device, and records a timestamp in the extracted PTP packet, and transmits the PTP packet as the time information to the time clock processing module;
  • the extracted packet includes the 1PPS and the TOD packet
  • the synchronization timing information in the 1PPS and the TOD packet is obtained, and the acquired synchronization timing information is sent to the time clock processing module as the time information.
  • the time clock processing module includes a time processing unit, a clock processing unit, and a synchronous device clock SEC unit respectively connected to the time processing unit and the clock processing unit.
  • the clock processing unit is configured to: when receiving the clock information, acquire an optimal clock according to the SSM in the clock information, and transmit the clock frequency in the optimal clock and the clock information to the SEC unit to complete the whole
  • the clock of the OTN network element device is synchronized; the received clock information is sent to the time clock transmission module.
  • the time processing unit is configured to: when the received time information includes the PTP message, calibrate the time of the OTN network element device according to the timestamp in the received PTP message, and add the PTP message to the received PTP message.
  • the time after the OTN network element device is calibrated, and the PTP message with the added time after the calibration is transmitted to the time clock transmission module; when the received time information includes the 1PPS and the TOD message, according to the 1PPS and the TOD message
  • the synchronization timing information is used to calibrate the time of the OTN network element device, and the 1PPS and TOD message encapsulated with the calibrated time is transmitted to the time clock transmission module.
  • the preset in-band transmission channel includes a line side service transmission channel and an electrical port optical port channel
  • the preset outband transmission channel includes an optical monitoring channel OSC and a clock cable channel.
  • the embodiment of the invention further provides a method for synchronizing OTN clock and time, and the method for synchronizing the OTN clock and time includes:
  • the OTN network element device determines a time clock transmission scheme according to the link type of the network in which the OTN network device is located, and extracts time information and clock information from the service port and/or the panel interface corresponding to the time clock transmission scheme;
  • the OTN network element device completes local clock synchronization according to the extracted clock information, and calibrates the local time according to the extracted time information;
  • the OTN network element device selects a preset in-band according to the determined time clock transmission scheme.
  • the transmission channel or the preset out-of-band transmission channel transmits the calibrated time information and the clock information that completes synchronization to the next-level OTN network element device.
  • the extracting time information and clock information includes:
  • the OTN network element device extracts a clock frequency and synchronization state information SSM from the service signal transmitted by the service port as the clock information, or extracts a clock frequency and an SSM as the clock from a signal transmitted by a panel clock source interface. information;
  • the OTN network element device extracts a precise time protocol PTP message or a second pulse (1PPS) and a time time constant (TOD) message from the service port and/or the panel interface as time information.
  • PTP time protocol
  • TOD time time constant
  • the extracting the PTP message or the 1PPS and the TOD message from the service port or the panel interface includes:
  • the OTN network element device is a PTP packet
  • the OTN network element device is a master node device
  • the timestamp of the OTN network element device the time-stamped PTP packet is used as the time information; if the OTN network element device is a slave node device, the PTP packet is used as the time information;
  • the OTN network element device When the OTN network element device extracts the packet from the service port and/or the panel interface as the 1PPS and the TOD packet, the synchronization timing information in the 1PPS and the TOD packet is obtained, and the acquired synchronization timing information is used as the time. information.
  • the OTN network element device completes local clock synchronization according to the clock information, and calibrating the local time according to the time information includes:
  • the OTN network element device When receiving the clock information, the OTN network element device obtains an optimal clock according to the SSM in the clock information, and completes clock synchronization of the entire OTN network element device according to the optimal clock and the clock frequency in the clock information.
  • the time of the OTN network element device is calibrated according to the timestamp in the received PTP message; or the time information received by the OTN network element device
  • the time of the OTN network element device is calibrated according to the synchronization timing information in the 1PPS and TOD packets.
  • the preset in-band transmission channel includes a line side service transmission channel and an electrical port optical port channel
  • the preset outband transmission channel includes an optical monitoring channel OSC and a clock cable channel.
  • the embodiment of the present invention further provides an OTN clock and time synchronization system, where the OTN clock and time synchronization system includes two or more OTN network element devices interconnected to form a ring network, and a packet transmission network PTN device.
  • the digital communication time frequency synchronization supply system BITS, the PTN device is connected to the ring network, and the OTN network element device in the ring network is connected to the BITS.
  • the technical solution provided by the embodiment of the present invention includes: a time clock extraction module, configured to determine a time clock transmission scheme according to a link type of a network where the OTN network element device is located; and corresponding to a time clock transmission scheme Time information and clock information are extracted from the service port or the panel interface; the time clock processing module is configured to: when receiving the clock information, complete clock synchronization of the OTN network element device according to the clock information; when receiving the time information, according to the The time information is used to calibrate the time of the OTN network element device; the time clock transmission module is configured to, according to the time clock transmission scheme, select an in-band transmission channel or an out-band transmission channel to transmit the received time information and clock information to the next-level OTN network element device. .
  • the embodiment of the invention implements the transmission of clock and time information by using the OTN network element device.
  • a time clock transmission module including an in-band transmission channel and an out-band transmission channel is set in the OTN network element device, so that the time clock transmission scheme corresponding to the link type of the network where the OTN network element device is located is selected.
  • the in-band transmission channel or the out-band transmission channel transmits the received time information and clock information to the next-level OTN network element device, and sets a service port in the OTN network element device that can receive time clock information transmitted by the in-band transmission channel and
  • the OTN network element device of the embodiment of the present invention can be connected to the only supported band by the OTN network element device in the embodiment of the present invention.
  • the in-band transmission and the out-of-band transmission are combined, so that the clock/time information can be smoothly transmitted from the OTN network element device in the related art.
  • the OTN network element device to the embodiment of the present invention can also be smoothly transmitted from the OTN network element device of the embodiment of the present invention to related technologies.
  • In the operation of the OTN network element device from The OTN network element device in the related art is fully utilized to transmit clock/time information, which saves the cost of re-networking.
  • FIG. 1 is a schematic diagram of functional modules of a first embodiment of an OTN network element device according to the present invention
  • FIG. 2 is a schematic diagram of functional modules of the time clock processing module of FIG. 1;
  • FIG. 3 is a schematic flowchart of a first embodiment of a method for synchronizing an OTN clock and time
  • FIG. 4 is a schematic diagram of a transmission scheme of the time clock transmission module of FIG. 1;
  • FIG. 5 is a schematic diagram of a network topology of an example 1 of an OTN clock and time synchronization method according to the present invention
  • FIG. 6 is a schematic diagram of a network topology of an example 3 of an OTN clock and time synchronization method according to the present invention.
  • the embodiment of the present invention provides an OTN network element device.
  • the OTN network element device includes: a time clock extraction module 10 and a time clock processing module. 20 and time clock transmission module 30, the time clock processing module 10 can be connected to the time clock extraction module 10 and the time clock transmission module 30 through a dedicated time clock channel (assuming the dedicated time clock channel is L),
  • the time clock extraction module 10 is configured to determine a time clock transmission scheme according to the link type of the network where the OTN network element device is located, and extract time information and clock information from the service port and/or the panel interface corresponding to the time clock transmission scheme. And the extracted time information and clock information are sent to the time clock processing module 20 via the dedicated time clock channel;
  • the link type of the network where the OTN network element device is located includes an OTN service link, an optical monitoring channel, a clock cable link, and an optical port electrical link, and the link type is generally classified into an outband transmission type and In-band transmission type
  • the time clock transmission scheme generally includes three types, the first one: the link type of the network where the OTN network element device is located is the out-of-band transmission type, the time clock transmission scheme provides the in-band transmission channel; the second type: The link type of the network where the OTN NE device is located is the in-band transmission type.
  • the inter-clock transmission scheme provides an out-of-band transmission channel; the third: regardless of the link type of the network in which the OTN network element device is located, the time-clock transmission scheme provides both an in-band transmission channel and an out-band transmission channel.
  • the inband transmission channel corresponds to the service port, and the outband transmission channel corresponds to the panel interface.
  • Service ports include a variety of synchronous Ethernet ports (such as FE (Fast Ethernet), Gigabit Ethernet (Gigabit Ethernet) ports, 10GE (10Gigabit Ethernet, 10 Gigabit Ethernet) ports Etc.), as well as OTN service ports, etc.
  • the panel interface includes 1PPS and TOD (1PPS (1Pulse Second), TOD (Time of Day)) port and 2MHz/2Mbists clock interface.
  • the 1PPS and TOD standard protocols mentioned in the embodiments of the present invention refer to the China Mobile Communication Enterprise Standard QB-B-016-2010 "China Mobile High-Precision Time Synchronization 1PPS plus TOD Interface Specification").
  • the clock information includes the SSM (Synchronization Status Message) and the clock frequency.
  • the time information includes the PTP (Precision Time Protocol) packet and the IPPS and TOD packets.
  • the time clock processing module 20 is configured to: when receiving the clock information, complete clock synchronization of the OTN network element device according to the clock information; and when receiving the time information, calibrate the time of the OTN network element device according to the time information;
  • the clock information and the time information are sent to the time clock transmission module via the dedicated time clock channel; here, the processed clock information includes the clock information after the clock synchronization and the time information of the calibrated OTN network element device.
  • the time clock processing module 20 is configured to select, according to the SSM in the clock information, an effective clock output with the highest priority or the highest clock quality level from the multiple clock sources to be preset to the time clock processing module.
  • the SEC unit In the SEC (Sychronous equipment clock) unit of 20, the SEC unit locks according to the input clock, and then outputs multiple clocks of different frequencies required by the OTN network element device, and synchronizes the entire clock according to the clock frequency in the clock information. Clock of the OTN network element device.
  • the time clock processing module 20 processes the received time information. When the received time information is a PTP message, the timestamp information transmitted in the message and the BMC (Best Master Clock algorithm) are used.
  • the time-to-time function of the local 1588 time of the OTN network element device After the local time is timed, the local timestamp is added/added to the sent PTP message and sent to the time clock transmission module 30; when the received time information is 1PPS and TOD report In the text, the timestamp is checked according to the timestamp latched in the TOPS frame format 1PPS signal in the 1PPS and TOD message, thereby realizing the calibration of the local time information of the OTN network element device, and then the local time information is sealed. The TOD frame is loaded and the encapsulated TOD frame is sent to the time clock transmission module 30.
  • the clock level included in the SSM may be: a primary clock PRC (a clock signal conforming to the G.811 standard, generally a cuckoo clock, a PRC highest priority); a secondary clock TNC (in accordance with G.812 standard clock signal, generally ⁇ clock); three-level clock LNC (local clock signal conforming to G.812 standard, generally ⁇ or crystal clock); four-time clock SETS (Synchronous Equipment Tinming Source, general It is a crystal clock); five-level clock UNKOWN (synchronous quality is unknown); the last clock is DNU (should not be used as a synchronous clock).
  • the priority is from one level to the last. Sort the clock levels given in the field and select the optimal clock.
  • the time clock transmission module 30 includes an in-band transmission channel and an out-band transmission channel, and is set to a time clock transmission scheme determined according to the time clock extraction module, and the in-band transmission channel or the out-band transmission channel is selected to be processed by the time clock processing module.
  • the time information and clock information are transmitted to the next-level OTN network element device.
  • the in-band transmission channel includes a line side service transmission channel and an electrical port optical port channel
  • the out-of-band transmission channel includes an optical monitoring channel OSC and a clock cable channel.
  • the time clock transmission module 30 provides four transmission schemes: the first is to pass clock/time information to the next OTN network element device through the OTN service on the line side, and this scheme belongs to in-band transmission.
  • the clock of the OTN is used as the bearer and the clock of the physical layer is synchronized.
  • the PTP packet or the SSM information encapsulated by the GFP (Generic Framing Procedure) is used to solve the clock in the clock/time extraction unit of the next OTN network element.
  • / time information to achieve clock / time synchronization
  • the second is to send clock / time information through the OSC channel transmission (Optical Supervisory Channel), this scheme is an out-of-band transmission.
  • the OSC channel includes an OSC unit and a Fibre Channel.
  • the OSC unit internally provides a clock processing unit and a synchronous Ethernet physical layer device that meet the EPC (Ethernet Equipment Clock) level 3 clock standard, establishes a synchronous Ethernet network at the wavelength of the OSC, and transmits the clock SSM information through the synchronous Ethernet. With the recovery clock of Ethernet, clock synchronization is realized. Under the condition of satisfying the clock synchronization, the interaction of the 1588 data packets of the Ethernet port is provided to realize the time synchronization of the nodes.
  • EPC Electronic Equipment Clock
  • the OSC channel adopts single-fiber bidirectional transmission mode, which can eliminate or reduce the asymmetric transmission and reception delay of the PTP port, so as to realize the function of eliminating the asymmetric delay without point-by-point correction; the third is to transmit the clock through the cable through the external interface of the panel/ Time information, this scheme also belongs to out-of-band transmission.
  • the panel external interface includes support for mobile 1PPS And the TOD standard protocol electrical port for transmitting time information, and an electrical port supporting 2 megahertz (MHz)/2 megabit (MBits) clock for transmitting clock frequency; the fourth is through 100 Mbps Ethernet (FE, Fast Ethernet) / Gigabit Ethernet (GE, Gigabit Ethernet) / 10GE electrical / optical port transmission clock / time information, this scheme is in-band transmission.
  • the local time is encapsulated in a PTP packet and then transmitted to other nodes through the electrical/optical port of the FE/GE/10GE.
  • the SSM information of the clock is parsed from the data of the slave node's Ethernet chip to implement the clock/ Time synchronization.
  • the time clock transmission scheme corresponding to the link type of the network where the OTN network element device is located is configured. Selecting an in-band transmission channel or an out-of-band transmission channel to transmit the received time information and clock information to the next-level OTN network element device, and setting a service capable of receiving time clock information transmitted by the in-band transmission channel in the OTN network element device.
  • the port and the panel interface that can receive the time clock information transmitted by the outband transmission channel so that the OTN network element device of the embodiment of the present invention supports both in-band transmission and out-band transmission, and the OTN network element device in the embodiment of the present invention can be connected to only In the OTN related to the OTN network element device supporting in-band transmission or only supporting out-of-band transmission, the in-band transmission and the out-of-band transmission are combined, so that the clock/time information can be smoothly obtained from the OTN network element in the related art.
  • the device can also be successfully transmitted from the OTN network element device of the embodiment of the present invention to the relevant OTN network element device.
  • the OTN network element device in the related art is fully utilized to transmit clock/time information, which saves the cost of re-networking.
  • a second embodiment of the OTN network element device of the present invention is provided on the basis of the first embodiment of the OTN network element device in the embodiment of the present invention.
  • the time clock extraction module 10 includes a clock extraction unit. 11 and time extraction unit 12,
  • the clock extraction unit 11 is configured to extract the clock frequency and the synchronization state information SSM from the service signal transmitted from the service port, or extract the clock frequency and the SSM from the signal transmitted by the panel clock source interface, and take the extracted clock frequency and the SSM as The clock information is transmitted to the time clock processing module 20;
  • the main function of the clock extraction unit 11 includes extracting the medium clock information from each clock source, one is to recover the clock frequency from the service signal, and extract the SSM from the service overhead of the service information, which belongs to the in-band transmission mode.
  • the other is the signal transmitted from the panel clock source interface.
  • the clock frequency and SSM are directly extracted, which is an out-of-band transmission method.
  • the time extracting unit 12 is configured to extract a precise time protocol (PTP) message or a second pulse (1PPS) and a time time constant (TOD) message from the service port and/or the panel interface, and extract the extracted PTP message or 1PPS And the TOD message is transmitted to the time clock processing module 20.
  • PTP precise time protocol
  • 1PPS second pulse
  • TOD time time constant
  • time extraction unit 12 is configured to:
  • the OTN network element device When the extracted packet includes a PTP packet, if the OTN network element device is the master node device, the timestamp of the OTN network element device is added to the extracted PTP packet, and the timestamp PTP is added. Transmitting the message as the time information to the time clock processing module; if the OTN network element device is a slave node device, transmitting the PTP message as the time information to the time clock processing module;
  • the extracted packet includes the 1PPS and the TOD packet
  • the synchronization timing information in the 1PPS and the TOD packet is obtained, and the acquired synchronization timing information is sent to the time clock processing module as the time information.
  • the main function of the time extracting unit 12 includes extracting time information from each time source, and the time extracting unit 12 extracts a PTP message or a 1PPS and TOD message from the service port or the panel interface. If the received message is a PTP message, the time extracting unit 12 adds a timestamp to the end of the message and performs a CRC check (Cyclic Redundancy Check); if the received message is 1PPS and TOD, the time extracting unit 12 extracts the synchronization timing information based on the TOD frame format. If a PTP packet is to be sent, the device needs to process the packet according to the master-slave relationship of the device.
  • CRC check Cyclic Redundancy Check
  • the device timestamp is set in the PTP packet and re-formed into the PTP packet. If the OTN network element device is a slave node device, record the timestamp in the PTP message, and then send the timestamp to the software to correct the time of the board. If the 1PPS and the TOD message are sent, the time extracting unit 12 encapsulates the Global Positioning System (GPS) information into the TOD frame, and transmits the TOD frame and the corresponding 1PPS signal.
  • GPS Global Positioning System
  • the time extracting unit 12 can also extract clock time information from the dedicated clock/time channel, and transmit the clock time information through the service port or the face interface.
  • the service port includes the synchronous Ethernet port in the related technology (FE 100M Ethernet/GE Gigabit Ethernet/10GE, 40GE, 100GE, and future 400GE, etc.), and also includes various OTN service ports;
  • the port includes 1PPS and TOD ports, as well as a 2MHz/2MBits clock interface.
  • the clock extraction unit 11 extracts the clock frequency and the SSM through the in-band and out-band transmission modes to synchronize the local clock of the OTN network element device, and the in-band and out-band transmission modes are adopted by the time extraction unit 12.
  • the PTP packet or the 1PPS and the TOD packet are extracted to calibrate the local time of the OTN network element device, so that the time clock extraction module 10 can support the time clock information transmitted by the previous network element device through the inband transmission channel or the outband transmission channel. .
  • the time clock processing module 20 includes time. a processing unit 22, a clock processing unit 21, and a synchronous device clock (SEC) unit 23 connected to the time processing unit 22 and the clock processing unit 21, respectively,
  • SEC synchronous device clock
  • the clock processing unit 21 is configured to, when receiving the clock information, acquire an optimal clock according to the SSM in the clock information, and transmit the clock frequency in the optimal clock and clock information to the SEC unit 23 to complete the clock of the entire OTN network element device. Synchronization; the received clock information is sent to the time clock transmission module 30.
  • the time processing unit 22 is configured to: when the received time information includes the PTP message, calibrate the time of the OTN network element device according to the timestamp in the received PTP message, and add the OTN network element device calibration in the received PTP message. After the time, the PTP message with the added time is transmitted to the time clock transmission module 30; when the received time information includes the 1PPS and the TOD message, the OTN network element is calibrated according to the synchronization timing information in the 1PPS and TOD message. The time of the device, and the 1PPS and TOD messages encapsulated with the post-calibration time are transmitted to the time clock transmission module 30.
  • the main function of the time clock processing module 20 includes processing the incoming clock time information, as shown in FIG.
  • the source of the clock time may include the time clock extraction module 10 transmitting through a dedicated time clock channel (the dedicated time clock channel of the embodiment of the present invention is a physical transmission line on the panel), and may also include the time clock transmission module 30 through dedicated By sending it over.
  • the clock information enters the clock processing unit 21, and the clock processing unit 21 selects one of the multi-channel clock sources with the highest priority or the highest clock quality level to output to the SEC unit 23 according to the software SSM algorithm, and the SEC unit 23 according to the input clock. Locking, and then outputting multiple clocks of different frequencies required by the device, the output clock is the same as the clock extracted by the clock/time extraction unit.
  • the processing of the time information is that the time processing unit 22 processes the transmitted PTP message or the 1PPS and TOD information. If the PTP packet is received, the BMC algorithm is used to perform the local 1588 time-based function according to the timestamp information sent in the packet. After the local time is synchronized, the PTP packet is sent with a local timestamp. Send it out. If the received is 1PPS and TOD, the timestamp inside the time processing unit 22 latched by the 1PPS signal is corrected according to the TOD frame format, and the local time information is calibrated, and then the local time information is encapsulated into the TOD frame format. The TOD frame and the corresponding 1PPS signal are transmitted.
  • the clock processing unit 21 selects The best clock with the highest priority is transmitted to the SEC unit 23, and the SEC unit 23 synchronizes the clock of the OTN network element device based on the effective clock and the clock frequency; the time processing unit is based on the PTP message and the timestamp pair in the 1PPS and TOD message.
  • the OTN network element device performs time calibration to synchronize the time and clock of the OTN network element device.
  • the embodiment of the present invention further provides a method for synchronizing OTN clock and time.
  • the OTN clock and time synchronization method includes:
  • Step 10 The OTN network element device determines a time clock transmission scheme according to the link type of the network in which the OTN network element is located, and extracts time information and clock information from the service port and/or the panel interface corresponding to the time clock transmission scheme.
  • the OTN network element device is implemented when receiving the time clock synchronization instruction.
  • the OTN network element device When the OTN needs to perform time clock synchronization, the OTN network element device extracts time information and clock information from its service port or panel interface.
  • the link types of the network where the OTN network element device is located include an OTN service link, an optical monitoring channel, a clock cable link, and an optical port electrical link.
  • the link types are generally classified into an outband transmission type and an inband transmission type.
  • the time clock transmission scheme generally includes three types. The first type: the link type of the network where the OTN network element device is located is the outband transmission type, the time clock transmission scheme provides the inband transmission channel, and the second type: where the OTN network element device is located.
  • the link type of the network is the in-band transmission type, the time clock transmission scheme provides the out-of-band transmission channel, and the third type: regardless of the OTN network element. What is the link type of the network where the device is located, and the time clock transmission scheme provides both an in-band transmission channel and an out-of-band transmission channel.
  • the inband transmission channel corresponds to the service port
  • the outband transmission channel corresponds to the panel interface.
  • Service ports include a variety of synchronous Ethernet ports (such as FE (Fast Ethernet), Gigabit Ethernet (Gigabit Ethernet) ports, 10GE (10Gigabit Ethernet, 10 Gigabit Ethernet) ports Etc.), as well as OTN service ports, etc.
  • the panel interface includes 1PPS and TOD (1PPS (1Pulse Second), TOD (Time of Day)) port and 2MHz/2Mbists clock interface.
  • the 1PPS and TOD standard protocols mentioned in the present invention refer to China Mobile Communications Enterprise Standard QB-B-016-2010 "China Mobile High-Precision Time Synchronous 1PPS and TOD Interface Specification").
  • the clock information includes the SSM (Synchronization Status Message) and the clock frequency.
  • the time information includes the PTP (Precision Time Protocol) packet and the IPPS and TOD packets.
  • Step 20 The OTN network element device completes local clock synchronization according to the extracted clock information, and calibrates the local time according to the extracted time information.
  • the OTN network element device selects, according to the SSM in the clock information, a valid clock with the highest priority or the highest clock quality level from the multiple clock sources to the SEC (Sychronous equipment clock) preset in the OTN network element device.
  • the device clock) unit the SEC unit locks according to the input clock, and then outputs multiple clocks of different frequencies required by the OTN network element device, and synchronizes the clock of the entire OTN network element device according to the clock frequency in the clock information.
  • the OTN network element device processes the received time information.
  • the received time information is a PTP message
  • the timestamp information transmitted in the message and the BMC (Best Master Clock algorithm) are used.
  • the timestamp is corrected according to the timestamp latched in the TOP frame format 1PPS signal in the 1PPS and TOD message, thereby The calibration of the local time information of the OTN network element device is implemented.
  • Step 30 The OTN network element device selects a preset in-band transmission channel or a preset out-of-band transmission channel to transmit the calibrated time information and the synchronized clock information to the next-level OTN network according to the determined time clock transmission scheme. Meta device.
  • the preset in-band transmission channel includes a line side service transmission channel and an electrical port optical port channel
  • the preset outband transmission channel includes an optical monitoring channel OSC and a clock cable channel.
  • the OTN network element device provides four transmission schemes: the first one is through the line side OTN service.
  • the clock/time information is passed to the next OTN network element device, which is an in-band transmission.
  • the clock/time synchronization is implemented in the clock/time extraction unit of the next OTN network element to implement clock/time synchronization by using the OTN reservation cost as the bearer and the physical layer clock synchronization to transmit the TP-encapsulated PTP packet or SSM information.
  • the second is to send clock/time information through the OSC channel (Optical Supervisory Channel), which is an out-of-band transmission.
  • the OSC channel includes an OSC unit and a Fibre Channel.
  • the OSC unit internally provides a clock processing unit and a synchronous Ethernet physical layer device that meet the EEC level 3 clock standard, establishes a synchronous Ethernet network at the wavelength of the OSC, transmits the clock SSM information through the synchronous Ethernet, and implements the clock with the Ethernet recovery clock. Synchronize. Under the condition of satisfying clock synchronization, the interaction of 1588 packets of the Ethernet port is provided to realize time synchronization of all nodes.
  • the OSC channel adopts single-fiber bidirectional transmission mode, which can eliminate or reduce the asymmetric transmission and reception delay of the PTP port, so as to realize the function of eliminating the asymmetric delay without point-by-point correction; the third is to transmit the clock through the cable through the external interface of the panel/ Time information, this scheme also belongs to out-of-band transmission.
  • the external interface of the panel includes an electrical port supporting the standard protocol of the mobile 1PPS and TOD for transmitting time information, and an electrical port supporting 2MHz/2MBits clock for transmitting the clock frequency; the fourth is by FE/GE/10GE.
  • the electrical/optical port transmits clock/time information. This scheme belongs to in-band transmission.
  • the local time is encapsulated in a PTP packet and then transmitted to other nodes through the electrical/optical port of the FE/GE/10GE.
  • the SSM information of the clock is parsed from the data of the slave node's Ethernet chip to implement the clock/ Time synchronization.
  • a time clock transmission module including an in-band transmission channel and an out-of-band transmission channel is set in the OTN network element device, and a time clock transmission scheme is determined according to a link type of a network where the OTN network element device is located, Then, according to the time clock transmission scheme, the in-band transmission channel or the out-band transmission channel is selected to transmit the received time information and clock information to the next-level OTN network element device, and the OTN network element device is configured to receive the in-band transmission channel transmission.
  • the service port of the time clock information and the panel interface that can receive the time clock information transmitted by the outband transmission channel, so that the OTN network element device of the embodiment of the present invention supports both in-band transmission and out-band transmission, and the OTN network element device in the embodiment of the present invention It can be connected to an OTN related to an OTN network element device that only supports in-band transmission or only supports out-of-band transmission, so that in-band transmission and out-of-band transmission can be combined, so that clock/time information can be smoothly obtained from related technologies.
  • the OTN network element device in the embodiment of the present invention can also be smoothly transmitted from the OTN of the embodiment of the present invention.
  • the network element device is transmitted to the OTN network element device in the related art, so as to fully utilize the OTN network element device in the related art to transmit the clock/ Time information saves the cost of re-networking.
  • step 10 includes:
  • Step 11 The OTN network element device extracts clock frequency and synchronization state information (SSM) as clock information from the service signal transmitted from the service port, or extracts a clock frequency and an SSM as clock information from a signal transmitted by the panel clock source interface;
  • SSM synchronization state information
  • the OTN network element device extracts the medium clock information from each clock source, one is to recover the clock frequency from the service signal, and extract the SSM from the service overhead of the service information, which belongs to the in-band transmission mode; One is to extract the clock frequency and SSM directly from the signal transmitted from the panel clock source interface. This method belongs to the out-of-band transmission mode.
  • Step 12 The OTN network element device extracts a precise time protocol (PTP) message or a second pulse (1PPS) and a time time constant (TOD) message from the service port and/or the panel interface.
  • PTP precise time protocol
  • 1PPS second pulse
  • TOD time time constant
  • step 12 includes:
  • the OTN network element device extracts the packet from the service port or the panel interface into a PTP packet
  • the OTN network element device is the master node device
  • the OTN network element is added to the extracted PTP packet.
  • the timestamp of the device is the time-stamped PTP packet as the time information. If the OTN network element device is the slave node device, the PTP packet is used as the time information.
  • the embodiment of the present invention can record the timestamp in the extracted PTP packet, and then send the PTP packet as time information.
  • Step 122 When the OTN network element device extracts the packet from the service port or the panel interface as the 1PPS and the TOD packet, the synchronization timing information in the 1PPS and the TOD packet is obtained, and the acquired synchronization timing information is used as the time information. .
  • the OTN network element device extracts the time information from each time source, and the OTN network element device extracts the PTP message or the 1PPS and the TOD message from the service port or the panel interface. If the received packet is a PTP packet, the time stamp is added to the end of the packet and the CRC check (Cyclic Redundancy Check) is performed. If the received packet is 1PPS and TOD, then The TOD frame format extracts synchronization timing information. If you want to send PTP packets, you need to set them according to the settings. If the OTN network element device is the master node, the local OTN network element device is configured as the master node, and the device timestamp is added to the PTP packet, and the PTP packet is re-formed.
  • CRC check Cyclic Redundancy Check
  • the OTN network element device is From the node, the timestamp in the PTP message is recorded, and then the timestamp is sent to the software for correction of the board time. If the 1PPS and TOD messages are sent, the GPS information is encapsulated into the TOD frame, and the TOD frame and the corresponding 1PPS signal are transmitted.
  • the OTN network element device can also extract clock time information from the dedicated clock/time channel, and transmit the clock time information through the service port or the face interface of the OTN network element device.
  • the service port includes the synchronous Ethernet port in the related technology (FE 100M Ethernet/GE Gigabit Ethernet/10GE, and 40GE, 100GE and future 400GE, etc.), and also includes the OTN service port; the panel interface includes 1PPS and TOD. Port, there are 2MHz/2MBits clock interface and so on.
  • the clock frequency and the SSM are extracted by using the in-band and out-band transmission modes to synchronize the local clock of the OTN network element device, and the PTP message or the 1PPS and TOD report are extracted through the in-band and out-band transmission modes.
  • the OTN network element device can support the local time of the OTN network element device, so that the OTN network element device can support the time clock information transmitted by the previous network element device through the inband transmission channel or the outband transmission channel.
  • step 20 includes:
  • Step 21 When receiving the clock information, the OTN network element device obtains an optimal clock according to the SSM in the clock information, and completes clock synchronization of the entire OTN network element device according to the optimal clock and the clock frequency in the clock information.
  • Step 22 When the time information received by the OTN network element device includes the PTP packet, the time of the OTN network element device is calibrated according to the timestamp in the received PTP packet; or
  • Step 23 When the time information received by the OTN network element device includes the 1PPS and the TOD message, the time of the OTN network element device is calibrated according to the synchronization timing information in the 1PPS and the TOD message.
  • the OTN network element device processes the clock time information transmitted, and the source of the clock time may be the dedicated time clock channel of the OTN network element device (the dedicated time clock channel referred to in the present invention) For the physical transmission line on the panel, it can also be transmitted by the OTN network element device through dedicated transmission.
  • the OTN network element device selects one of the multiple clock sources with the highest priority or the highest clock quality level to output to the SEC unit according to the software SSM algorithm, and the SEC unit performs the clock according to the input clock.
  • the output clock is clocked with the clock extracted by the clock/time extraction unit, so that the clock of the entire device is clock synchronized by the SEC unit 23.
  • the processing of the time information is that the OTN network element device processes the transmitted PTP message or the 1PPS and TOD information. If the PTP packet is received, the BMC algorithm is used to perform the local 1588 time-based function according to the timestamp information sent in the packet. After the local time is synchronized, the PTP packet is sent with a local timestamp. Send it out.
  • the timestamp inside the OTN network element device latched by the 1PPS signal is corrected according to the TOD frame format, and the local time information is calibrated, and then the local time information is encapsulated into the TOD frame format.
  • the TOD frame and the corresponding 1PPS signal are transmitted.
  • the SEC unit by setting an SEC unit in the OTN network element device, by selecting the valid clock with the highest priority and transmitting to the SEC unit, the SEC unit synchronizes the clock of the OTN network element device based on the effective clock and the clock frequency;
  • the time stamp in the packet and the 1PPS and TOD packets is time-aligned to the OTN network element device to synchronize the time and clock of the OTN network element device.
  • the embodiment of the invention further provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions are used to execute the OTN clock and time synchronization method.
  • the embodiment of the present invention further provides an OTN clock and time synchronization system.
  • the OTN clock and time synchronization system includes two or two OTN network element devices interconnected to form a ring network, and a PTN (Packet Transport Network).
  • the device and the BITS, the PTN device is connected to the ring network, and the OTN network element device in the ring network is connected to the BITS.
  • the PTN device is connected to multiple base stations, and the OTN network element device connected to the BITS is used as the primary site.
  • the description of the embodiment is made by taking the metropolitan area network as an example.
  • the access layer of the metropolitan area network belongs to the alternate period of the old and new transmission networks.
  • the access layer can satisfy the Any-Rate-Service (multi-service access) and can have the edge layer OTN network and the core layer.
  • the end-to-end transmission of the OTN network also requires long-distance, large-bandwidth transmission.
  • SDH/PTN devices SDH (Synchronous Digital Hierarchy), PTN (Packet Transport Network)
  • SDH/PTN devices not only support multi-service bearers, but also support all Network clock / time synchronization function.
  • the clock/time synchronization function needs to be considered for transmission in the OTN network.
  • the four sites of the OTN network element devices A, B, C, and D form an OTN ring network, and the client side accesses the PTN service, wherein the dotted line network represents the clock/time synchronization transmission network.
  • the C site serves as the primary site (or the primary node) and is connected to the BITS (Building Integrated Timing Supply System).
  • BITS built-in GPS receiver and crystal oscillator unit can be configured to generate first, second and third clocks, with an external clock interface, can provide 2MHz/2MBits output, and clock SSM information extraction and generation; BITS The satellite timing signal is received by the GPS receiver, and the time information is output from the panel interface (FE/GE/10GE optical port/electrical port, or 1PPS and TOD electrical port) after being processed by the timestamp extraction and generation in the board.
  • the panel interface FE/GE/10GE optical port/electrical port, or 1PPS and TOD electrical port
  • the C site receives the clock/time information through the 2MHz/2MBits external clock interface of BITS and the 1PPS and TOD electrical ports, and enters the C station to enter the time clock extraction module to extract the clock time information.
  • the time clock extraction module extracts the clock/time information and directly extracts the clock frequency and SSM information from the signal transmitted from the panel 2MHz/2MBits external clock source interface, and then sends it through a dedicated channel.
  • Time clock processing module After the clock information enters the time clock processing module, the time clock processing module outputs the clock source to the SEC unit according to the software SSM algorithm, the SEC unit locks on the input clock, and then the SEC unit outputs multiple different frequencies required by the device.
  • the clock of the C-site device is clock-synchronized by the SEC unit, that is, the service clock outputted by the C station and the system clock running inside the device are all clocks homologous to the clock output by the BITS.
  • the time clock processing module of the C site encapsulates the clock SSM information into the reserved overhead of the OTUk on the line side, and uses the reserved overhead of the OTN as a bearer to transmit the clock to the B site through the time clock transmission module.
  • the time information is from the 1PPS and TOD electrical ports, and the time clock extraction module extracts the synchronization timing information according to the TOD frame format.
  • Time clock extraction module will be The GPS information is encapsulated into a TOD frame, and the TOD frame and the corresponding 1PPS signal are transmitted to the time clock processing module, and the time stamp of the time clock processing module latched by the 1PPS signal is corrected according to the TOD frame format to implement local time information.
  • the local time information is encapsulated into the TOD frame format, and the TOD frame and the corresponding 1PPS signal are transmitted to the time clock transmission module, and the time clock transmission module is transmitted to the 1PPS of the B site through the 1PPS and TOD electrical port cable channel. And the electrical interface of the TOD.
  • the processing flow of the B site is the same as that of the C site.
  • the time clock extraction module and the time clock processing module also implement the clock synchronization in the B site, and the time synchronization with the C site, and transmit the clock time information through the time clock transmission module. Go to the A site. The processing flow of the A site is also the same as that of the C site.
  • the time clock extraction module and the time clock processing module also implement the clock synchronization in the A site, and the time synchronization with the B and C sites, and then the A site passes the time clock transmission module.
  • the GE synchronous Ethernet service on the client side transmits the clock time information to the PTN device.
  • the PTN device extracts the clock/time information from the GE synchronous Ethernet service, and after processing, distributes it to each base station. This achieves clock/time synchronization of the OTN and PTN networks.
  • the four sites of the OTN network element devices A, B, C, and D form an independent OSC channel in the OTN ring network. While providing the monitoring optical transmission function, the OSC channel can also be used to transmit the clock/time. information.
  • the specific implementation scheme is as follows: The processing mode of the C-site time clock extraction module and the time clock processing module is the same as that of the first example. The difference is that the example 2 does not transmit the clock/time information through the line side overhead, but the C-site time clock transmission module. Select to pass the clock time information to the B site through the OSC Fibre Channel (as shown in Figure 5, the dotted line network between the C and B sites).
  • the OSC unit Before entering the OSC Fibre Channel, the OSC unit transmits the clock SSM information and the service recovery clock to the B site through the GE synchronous Ethernet to synchronize the clocks of the C and B sites. Under the condition of satisfying the clock synchronization, the OSC unit provides the interaction of the 1588V2 data packet of the GE synchronous Ethernet port to implement time synchronization between the C and B stations.
  • the OSC unit of the B site receives the information transmitted by the Fibre Channel, enters the time clock extraction module, and the time clock processing module implements the clock synchronization in the B site, and synchronizes with the time of the C site, and transmits the OSC in the module through the time clock.
  • the channel passes the clock time information to the A site.
  • the processing flow of the A site is the same as that of the B site.
  • the time clock extraction module and the time clock processing module are also used to realize the clock synchronization in the A site and the time synchronization with the B and C sites, and then the A site passes the time clock transmission module.
  • the GE synchronous Ethernet service on the customer side passes the clock time information down to the PTN device, and the PTN device synchronizes the Ethernet industry from GE.
  • the clock/time information is extracted and processed and distributed to each base station. This achieves clock/time synchronization of the OTN and PTN networks.
  • an independent clock/time transmission network is introduced, and the dotted line represents an independent clock/time transmission network.
  • the time-clock extraction module of the C site extracts the clock/time information through the 2MHz/2MBits external clock interface of the BITS and the 1PPS and TOD electrical ports, and processes the clock/time information through the independent clock.
  • the time/time transmission network transmits the time clock extraction module to the three sites A, B, and D to realize the clock/time synchronization of the ring network composed of ABCD.
  • Independent clock/time transmission networks include not only the following forms: the 2m/2MBits clock cable network, the electrical port cable network that transmits 1PPS and TOD information, and the fiber that transmits Ethernet FE/GE/10GE. Network, or Ethernet port network of FE/GE/10GE. Thereby achieving high precision ring clock/time synchronization.
  • each module/unit in the foregoing embodiment may be implemented in the form of hardware, for example, by implementing an integrated circuit to implement its corresponding function, or may be implemented in the form of a software function module, for example, being executed by a processor and stored in a memory. Programs/instructions to implement their respective functions.
  • the invention is not limited to any specific form of combination of hardware and software.
  • the above technical solution realizes the transmission of clock and time information by using the OTN network element device.

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Abstract

一种光传输网(OTN)网元设备、OTN时钟和时间的同步方法及系统，包括：时间时钟提取模块，设置为，根据OTN网元设备所在网络的链路类型，确定时间时钟传输方案；并从时间时钟传输方案对应的业务端口或面板接口中提取出时间信息和时钟信息；时间时钟处理模块设置为，在接收到时钟信息时，根据该时钟信息完成OTN网元设备的时钟同步；在接收时间信息时，根据该时间信息校准OTN网元设备的时间；时间时钟传输模块设置为，根据时间时钟传输方案，选择带内传输通道或带外传输通道将接收的时间信息和时钟信息传输至下一级OTN网元设备。本发明实施例利用OTN网元设备实现了时钟和时间信息的传送。

Description

一种OTN网元设备、OTN时钟和时间的同步方法及系统 技术领域
本文涉及但不限于网络通信技术领域，尤其涉及一种光传输网(OTN，Optical Transport Network)网元设备、OTN时钟和时间的同步方法及系统。
背景技术
OTN通常也称为OTH(Optical Transport Hierarchy，光传送体系)，是G.872、G.709、G.798等一系列国际电信联盟远程通信标准化组织的建议所规范的新一代光传送体系。OTN综合了SDH(Synchronous Digital Hierarchy，同步数字体系)的优点和WDM(Wavelength Division Multiplexing，波分复用)的带宽可扩展性，集传送和交换能力于一体，代表了下一代传送网的发展方向。
随着OTN网络技术的不断发展，在光传送网中传输高精度的时钟/时间信息成为热点话题。目前，最常见的传输方案是采用同步以太网和IEEE 1588V2协议，通过传输网络实现时钟/时间信号的传送，这样在OTN网络中就可以组成一个端到端的时钟/时间同步传送网络。而时钟/时间信号的传输方案主要有两种，一种是带内传输，带内传输方案包括通过业务信号传送1588信息(例如时钟频率)和时钟的SSM(Synchronization Status Message，同步状态信息)；另一种是带外传输，带外传输方案包括通过OTN网络中的外部通道，传送1588信息和时钟的SSM；但是，相关技术中的OTN中的网元设备一般只支持一种时钟/时间信号的传输方式，即OTN中网元设备无法同时支持带内传输和带外传输，无法充分利用相关技术中的OTN中网元设备来传送时钟和时间信息。
发明内容
以下是对本文详细描述的主题的概述。本概述并非是为了限制权利要求的保护范围。
本发明实施例提供了一种OTN网元设备、OTN时钟和时间的同步方法及系统，能够利用OTN中网元设备传送时钟和时间信息。
本发明实施例提供的一种光传输网(OTN)网元设备，所述OTN网元设备包括：时间时钟提取模块、时间时钟处理模块和时间时钟传输模块，所述时间时钟处理模块通过专用时间时钟通道分别与所述时间时钟提取模块和时间时钟传输模块连接，
所述时间时钟提取模块设置为，根据所述OTN网元设备所在网络的链路类型，确定时间时钟传输方案；从所述时间时钟传输方案对应的业务端口和/或面板接口中提取出时间信息和时钟信息，并将提取的时间信息和时钟信息经专用时间时钟通道发送至所述时间时钟处理模块；
所述时间时钟处理模块设置为，接收到所述时钟信息时，根据接收到的时钟信息完成所述OTN网元设备的时钟同步；接收所述时间信息时，根据接收到的时间信息校准所述OTN网元设备的时间；并将处理后的时钟信息和时间信息经专用时间时钟通道发送至所述时间时钟传输模块；
所述时间时钟传输模块包括带内传输通道和带外传输通道，设置为根据时间时钟提取模块确定的时间时钟传输方案，选择带内传输通道或带外传输通道将接收的由时间时钟处理模块处理后的时间信息和时钟信息传输至下一级OTN网元设备。
可选地，所述时间时钟提取模块包括时钟提取单元和时间提取单元，
所述时钟提取单元，设置为从业务端口传出的业务信号中提取时钟频率和同步状态信息SSM，或者从面板时钟源接口传输的信号中提取时钟频率和SSM，并将提取的时钟频率和SSM作为所述时钟信息传输至所述时间时钟处理模块；
所述时间提取单元，设置为从业务端口和/或面板接口中提取精确时间协议PTP报文或秒脉冲1PPS及日时间常数TOD报文，并将提取的PTP报文或1PPS及TOD报文作为时间信息传输至所述时间时钟处理模块。
可选地，所述时间提取单元是设置为：
当提取的报文包括PTP报文时，若所述OTN网元设备为主节点设备，则在该提取的PTP报文中添加所述OTN网元设备的时间戳，并将添加时间戳的PTP报文作为所述时间信息传输至所述时间时钟处理模块；若所述OTN 网元设备为从节点设备，则记录提取的PTP报文中的时间戳，将该PTP报文作为所述时间信息传输至所述时间时钟处理模块；
当提取的报文包括1PPS及TOD报文时，获取1PPS及TOD报文中的同步定时信息，并将获取的该同步定时信息作为所述时间信息发送至所述时间时钟处理模块。
可选地，所述时间时钟处理模块包括时间处理单元、时钟处理单元以及分别与所述时间处理单元和时钟处理单元连接的同步设备时钟SEC单元，
所述时钟处理单元设置为，接收到时钟信息时，根据时钟信息中的SSM获取最佳时钟，并将所述最佳时钟和所述时钟信息中的时钟频率传输至所述SEC单元以完成整个所述OTN网元设备的时钟同步；将接收的所述时钟信息发送至所述时间时钟传输模块。
所述时间处理单元设置为，接收到的时间信息包括PTP报文时，根据接收的PTP报文中的时间戳，校准所述OTN网元设备的时间，并在接收的PTP报文添加所述OTN网元设备校准后时间，并将添加校准后时间的PTP报文传输至所述时间时钟传输模块；接收到的时间信息包括1PPS及TOD报文时，根据所述1PPS及TOD报文中的同步定时信息校准所述OTN网元设备的时间，并将封装有所述校准后时间的1PPS及TOD报文传输至所述时间时钟传输模块。
可选地，所述预设的带内传输通道包括线路侧业务传输通道和电口光口通道，所述预设的带外传输通道包括光监控通道OSC和时钟线缆通道。
本发明实施例还提供一种OTN时钟和时间的同步方法，所述OTN时钟和时间的同步方法包括：
OTN网元设备根据其所在网络的链路类型，确定时间时钟传输方案，并从该时间时钟传输方案对应的业务端口和/或面板接口中提取时间信息和时钟信息；
所述OTN网元设备根据提取的所述时钟信息完成本地的时钟同步，根据提取的所述时间信息校准本地的时间；
所述OTN网元设备根据确定的所述时间时钟传输方案，选择预设的带内 传输通道或预设的带外传输通道将校准后的时间信息和完成同步的时钟信息传输至下一级OTN网元设备。
可选地，所述提取时间信息和时钟信息包括：
所述OTN网元设备根据所述时间时钟传输方案确定提取时间时钟信息的业务端口和/或面板接口；
所述OTN网元设备从所述业务端口传出的业务信号中提取时钟频率和同步状态信息SSM作为所述时钟信息，或者从面板时钟源接口传输的信号中提取时钟频率和SSM作为所述时钟信息；
所述OTN网元设备从所述业务端口和/或面板接口中提取精确时间协议PTP报文或秒脉冲(1PPS)及日时间常数(TOD)报文作为时间信息。
可选地，所述从所述业务端口或面板接口中提取PTP报文或1PPS及TOD报文包括：
当所述OTN网元设备从业务端口和/或面板接口中提取的报文为PTP报文时，若所述OTN网元设备为主节点设备，则在该提取的PTP报文中添加所述OTN网元设备的时间戳，将添加时间戳的PTP报文作为所述时间信息；若所述OTN网元设备为从节点设备，将该PTP报文作为所述时间信息；
当所述OTN网元设备从业务端口和/或面板接口中提取的报文为1PPS及TOD报文时，获取1PPS及TOD报文中的同步定时信息，将获取的同步定时信息作为所述时间信息。
可选地，所述OTN网元设备根据所述时钟信息完成本地的时钟同步，根据所述时间信息校准本地的时间包括：
所述OTN网元设备接收到时钟信息时，根据时钟信息中的SSM获取最佳时钟，并根据所述最佳时钟和所述时钟信息中的时钟频率完成整个OTN网元设备的时钟同步。
所述OTN网元设备接收到的时间信息包括PTP报文时，根据接收的PTP报文中的时间戳校准所述OTN网元设备的时间；或者，所述OTN网元设备接收到的时间信息包括1PPS及TOD报文时，根据该1PPS及TOD报文中的同步定时信息校准所述OTN网元设备的时间。
可选地，所述预设的带内传输通道包括线路侧业务传输通道和电口光口通道，所述预设的带外传输通道包括光监控通道OSC和时钟线缆通道。
本发明实施例还提供一种OTN时钟和时间的同步系统，所述OTN时钟和时间的同步系统包括两个或两个以上互相连接组成环型网络的OTN网元设备、分组传输网PTN设备和数字通信时间频率同步供给系统BITS，所述PTN设备与所述环型网络中连接，所述环型网络中OTN网元设备与所述BITS连接。
与相关技术相比，本发明实施例提供的技术方案，包括：时间时钟提取模块，设置为，根据OTN网元设备所在网络的链路类型，确定时间时钟传输方案；并从时间时钟传输方案对应的业务端口或面板接口中提取出时间信息和时钟信息；时间时钟处理模块设置为，在接收到时钟信息时，根据该时钟信息完成OTN网元设备的时钟同步；在接收时间信息时，根据该时间信息校准OTN网元设备的时间；时间时钟传输模块设置为，根据时间时钟传输方案，选择带内传输通道或带外传输通道将接收的时间信息和时钟信息传输至下一级OTN网元设备。本发明实施例利用OTN网元设备实现了时钟和时间信息的传送。
本发明实施例通过在OTN网元设备中设置同时包括带内传输通道和带外传输通道的时间时钟传输模块，从而根据OTN网元设备所在网络的链路类型所对应的时间时钟传输方案，选择带内传输通道或者带外传输通道将接收的时间信息和时钟信息传输至下一级OTN网元设备，并且在OTN网元设备中设置可接收带内传输通道传输的时间时钟信息的业务端口和可接收带外传输通道传输的时间时钟信息的面板接口，从而使得本发明实施例OTN网元设备同时支持带内传输和带外传输，本发明实施例OTN网元设备可以连接于由仅支持带内传输或仅支持带外传输的OTN网元设备组成的相关技术的OTN中，使带内传输和带外传输相结合，从而时钟/时间信息可以顺利地从相关技术中的OTN网元设备传输到本发明实施例的OTN网元设备，也可以顺利地从本发明实施例的OTN网元设备传输至相关技术中的OTN网元设备中，从 而充分利用相关技术中的OTN网元设备来传送时钟/时间信息，节省了重新组网的成本。
在阅读并理解了附图和详细描述后，可以明白其他方面。
附图概述
图1为本发明OTN网元设备的第一实施例的功能模块示意图；
图2为图1中时间时钟处理模块的功能模块示意图；
图3为OTN时钟和时间的同步方法第一实施例的流程示意图；
图4为图1中时间时钟传输模块的传输方案示意图；
图5为本发明OTN时钟和时间的同步方法示例一的网络拓扑示意图；
图6为本发明OTN时钟和时间的同步方法示例三的网络拓扑示意图。
本发明的实施方式
下文中将结合附图对本申请的实施例进行详细说明。需要说明的是，在不冲突的情况下，本申请中的实施例及实施例中的特征可以相互任意组合。
本发明实施例提供了一种OTN网元设备，在本发明OTN网元设备的第一实施例中，参照图1，该一种OTN网元设备包括：时间时钟提取模块10、时间时钟处理模块20和时间时钟传输模块30，时间时钟处理模块10可以通过专用时间时钟通道(假设专用时间时钟通道为L)分别与时间时钟提取模块10和时间时钟传输模块30连接，
时间时钟提取模块10设置为，根据OTN网元设备所在网络的链路类型，确定时间时钟传输方案，并从时间时钟传输方案对应的业务端口和/或面板接口中提取出时间信息和时钟信息，并将提取的时间信息和时钟信息经专用时间时钟通道发送至时间时钟处理模块20；
本发明实施例，OTN网元设备所在网络的链路类型包括OTN业务链路、光监控通道、时钟线缆链路、光口电口链路等，链路类型总体分为带外传输类型和带内传输类型，时间时钟传输方案大致包括三种，第一种：在OTN网元设备所在网络的链路类型为带外传输类型，时间时钟传输方案提供带内传输通道；第二种：在OTN网元设备所在网络的链路类型为带内传输类型，时 间时钟传输方案提供带外传输通道；第三种：无论OTN网元设备所在网络的链路类型是什么，时间时钟传输方案同时提供带内传输通道和带外传输通道。带内传输通道对应业务端口，带外传输通道对应面板接口。
业务端口包括多种同步以太网端口(例如FE(Fast Ethernet，快速以太网或百兆以太网)端口、GE(Gigabit Ethernet，千兆以太网)端口、10GE(10Gigabit Ethernet，万兆以太网)端口等)，以及OTN业务端口等，面板接口包括1PPS及TOD(1PPS(1Pulse Second，秒脉冲)，TOD(Time of Day，日时间常数))端口和2MHz/2Mbists时钟接口等。本发明实施例提及的1PPS及TOD标准协议是指中国移动通信企业标准QB-B-016-2010《中国移动高精度时间同步1PPS加TOD接口规范》)。时钟信息包括SSM(Synchronization Status Message，同步状态信息)和时钟频率，时间信息包括PTP((Precision Time Protocol，精确时间协议)报文和IPPS及TOD报文。
时间时钟处理模块20设置为，在接收到时钟信息时，根据该时钟信息完成OTN网元设备的时钟同步；在接收到时间信息时，根据该时间信息校准OTN网元设备的时间；并将处理后的时钟信息和时间信息经专用时间时钟通道发送至时间时钟传输模块；这里，处理后的时钟信息包括时钟同步后的时钟信息和校准后的OTN网元设备的时间信息。
可选的，时间时钟处理模块20是设置为，根据时钟信息中的SSM，从多路时钟源中选出一路优选级最高或时钟质量等级最高的有效时钟输出给预设于该时间时钟处理模块20中的SEC(Sychronous equipment clock，同步设备时钟)单元，SEC单元根据输入的时钟进行锁定，然后输出OTN网元设备所需的多路不同频率的时钟，并根据时钟信息中的时钟频率同步整个OTN网元设备的时钟。时间时钟处理模块20对接收的时间信息进行处理，当接收的时间信息为PTP报文，则根据报文里传送过来的时间戳信息和BMC(Best Master Clock algorithm，最佳主时钟算法)，进行OTN网元设备本地1588时间的对时功能，本地时间对时后，再对发送的PTP报文打上/添加本地时间戳并发送给时间时钟传输模块30；当接收的时间信息为1PPS及TOD报文时，则根据1PPS及TOD报文中的TOD帧格式1PPS信号中锁存的时间戳进行校正，从而实现OTN网元设备本地时间信息的校准，然后在将本地时间信息封 装到TOD帧中并将封装后TOD帧发给时间时钟传输模块30。
需要说明的是，本发明实施例，SSM中包括的时钟等级可以为：一级钟PRC(符合G.811标准的时钟信号，一般为铯钟，PRC最高优先级)；二级钟TNC(符合G.812标准的时钟信号，一般为铷钟)；三级钟LNC(符合G.812标准的本地局时钟信号，一般为铷钟或晶体钟)；四级钟SETS(Synchronous Equipment Tinming Source，一般为晶体钟)；五级钟UNKOWN(同步质量不知道)；最后一级钟为DNU(不应用作同步钟)。优先级从一级到最后。按照现场所给的时钟等级进行排序，选择最优时钟。
时间时钟传输模块30包括带内传输通道和带外传输通道，设置为根据时间时钟提取模块确定的时间时钟传输方案，选择带内传输通道或带外传输通道将接收的由时间时钟处理模块处理后的时间信息和时钟信息传输至下一级OTN网元设备。
可选地，带内传输通道包括线路侧业务传输通道和电口光口通道，所述带外传输通道包括光监控通道OSC和时钟线缆通道。
参照图4，时间时钟传输模块30提供四种传输方案：第一种是通过线路侧的OTN业务将时钟/时间信息传递给下一个OTN网元设备，这种方案属于带内传输。以OTN的保留开销为载体，配合物理层时钟同步，传递经过:通用成帧规程(GFP，GenericFramingProcedure)封装的PTP报文或SSM信息，在下一个OTN网元的时钟/时间提取单元中解出时钟/时间信息，实现时钟/时间同步；第二种是通过OSC通道传(Optical Supervisory Channel，光监控通道)送时钟/时间信息，这种方案属于带外传输。OSC通道包括OSC单元和光纤通道。OSC单元内部提供满足同步以太网时钟(EEC，Ethernet Equipment Clock)3级时钟标准的时钟处理单元和同步以太网物理层器件，在OSC的波长上建立同步以太网，通过同步以太网传递时钟SSM信息，配合以太网的恢复钟，实现时钟同步。在满足时钟同步的条件下，提供以太网端口的1588数据包的交互以实现节点的时间同步。OSC通道采用单纤双向的传输方式，可以消除或者减少PTP端口的收发延时不对称，以实现无需逐点校正不对称延时的功能；第三种是通过面板外部接口经过线缆传送时钟/时间信息，这种方案也属于带外传输。其中面板外部接口包括支持中移动1PPS 及TOD的标准协议的电口，用于传送时间信息，和支持2兆赫兹(MHz)/2兆比特(MBits)时钟的电口，用于传送时钟频率；第四种是通过百兆以太网(FE，Fast Ethernet)/千兆以太网(GE，Gigabit Ethernet)/10GE的电口/光口传送时钟/时间信息，这种方案属于带内传输。将本地时间封装到PTP报文中，然后通过FE/GE/10GE的电口/光口传送给其他节点，时钟的SSM信息则通过从节点的以太网芯片从数据中解析出来，从而实现时钟/时间同步。
在本实施例中，通过在OTN网元设备中设置同时包括带内传输通道和带外传输通道的时间时钟传输模块，从而根据OTN网元设备所在网络的链路类型所对应的时间时钟传输方案，选择带内传输通道或者带外传输通道将接收的时间信息和时钟信息传输至下一级OTN网元设备，并且在OTN网元设备中设置可接收带内传输通道传输的时间时钟信息的业务端口和可接收带外传输通道传输的时间时钟信息的面板接口，从而使得本发明实施例OTN网元设备同时支持带内传输和带外传输，本发明实施例OTN网元设备可以连接于由仅支持带内传输或仅支持带外传输的OTN网元设备组成的相关技术的OTN中，使带内传输和带外传输相结合，从而时钟/时间信息可以顺利地从相关技术中的OTN网元设备传输到本发明实施例的OTN网元设备，也可以顺利地从本发明实施例的OTN网元设备传输至相关技术中的OTN网元设备中，从而充分利用相关技术中的OTN网元设备来传送时钟/时间信息，节省了重新组网的成本。
可选地，在本发明实施例OTN网元设备第一实施例的基础上，提出本发明OTN网元设备的第二实施例，在第二实施例中，时间时钟提取模块10包括时钟提取单元11和时间提取单元12，
时钟提取单元11，设置为从业务端口传出的业务信号中提取时钟频率和同步状态信息SSM，或者从面板时钟源接口传输的信号中提取时钟频率和SSM，并将提取的时钟频率和SSM作为时钟信息传输至时间时钟处理模块20；
时钟提取单元11主要功能包括从每一个时钟源中提取中时钟信息，一种是从业务信号中恢复出时钟频率，并从业务信息的业务开销中提取出SSM，这种方式属于带内传送方式；另一种是从面板时钟源接口传输过来的信号中 直接提取出时钟频率和SSM，这种方式属于带外传送方式。
时间提取单元12，设置为从业务端口和/或面板接口中提取精确时间协议(PTP)报文或秒脉冲(1PPS)及日时间常数(TOD)报文，并将提取的PTP报文或1PPS及TOD报文传输至时间时钟处理模块20。
可选地，时间提取单元12是设置为：
当提取的报文包括PTP报文时，若所述OTN网元设备为主节点设备，则在该提取的PTP报文中添加所述OTN网元设备的时间戳，并将添加时间戳的PTP报文作为所述时间信息传输至所述时间时钟处理模块；若所述OTN网元设备为从节点设备，将该PTP报文作为所述时间信息传输至所述时间时钟处理模块；
当提取的报文包括1PPS及TOD报文时，获取1PPS及TOD报文中的同步定时信息，并将获取的该同步定时信息作为所述时间信息发送至所述时间时钟处理模块。
时间提取单元12主要功能包括从每一个时间来源中提取出时间信息，时间提取单元12从业务端口或面板接口中提取出PTP报文或1PPS及TOD报文。如果接收的报文为PTP报文，则时间提取单元12在其报文尾部打上时间戳并重新进行CRC校验(Cyclic Redundancy Check，循环冗余校验码)；如果接收的报文为1PPS及TOD，则时间提取单元12根据TOD帧格式提取出同步定时信息。如果要发送PTP报文，则需根据设备的主从关系分别进行报文的处理，如果本OTN网元设备是主节点设备，则在PTP报文中打上本设备时间戳，并重新组成PTP报文发送出去；如果本OTN网元设备是从节点设备，则记录PTP报文里的时间戳，然后把这个时间戳送给软件进行本板时间的修正。如果发送的是1PPS及TOD报文，则时间提取单元12将全球定位系统(GPS，Global Positioning System)信息封装到TOD帧里，将TOD帧与对应的1PPS信号传送出去。
此外，时间提取单元12也可以从专用时钟/时间通道中提取出时钟时间信息，通过业务端口或面部接口将时钟时间信息传送出去。其中业务端口包括相关技术中的同步以太网端口(FE百兆以太网/GE千兆以太网/10GE，以及40GE，100GE和未来的400GE等)，还包括多种OTN业务端口；面板接 口包括1PPS及TOD端口，还有2MHz/2MBits时钟接口等。
在本实施例中，通过时钟提取单元11经带内和带外两种传送方式提取时钟频率和SSM以同步OTN网元设备本地时钟，通过时间提取单元12经带内和带外两种传送方式提取PTP报文或1PPS及TOD报文以对OTN网元设备本地时间进行校准，从而时间时钟提取模块10能够支持提取上一个网元设备通过带内传输通道或者带外传输通道传送的时间时钟信息。
可选地，在本发明OTN网元设备第二实施例的基础上，提出本发明OTN网元设备的第三实施例，在第三实施例中，参照图2，时间时钟处理模块20包括时间处理单元22、时钟处理单元21以及分别与时间处理单元22和时钟处理单元21连接的同步设备时钟(SEC)单元23，
时钟处理单元21设置为，接收到时钟信息时，根据时钟信息中的SSM获取最佳时钟，并将最佳时钟和时钟信息中的时钟频率传输至SEC单元23以完成整个OTN网元设备的时钟同步；将接收的时钟信息发送至时间时钟传输模块30。
时间处理单元22设置为，接收到的时间信息包括PTP报文时，根据接收的PTP报文中的时间戳，校准OTN网元设备的时间，并在接收的PTP报文添加OTN网元设备校准后时间，并将添加校准后时间的PTP报文传输至时间时钟传输模块30；接收到的时间信息包括1PPS及TOD报文时，根据该1PPS及TOD报文中的同步定时信息校准OTN网元设备的时间，并将封装有校准后时间的1PPS及TOD报文传输至时间时钟传输模块30。
时间时钟处理模块20主要功能包括对传输进来的时钟时间信息进行处理，如图2所示。时钟时间的来源可以包括时间时钟提取模块10通过专用时间时钟通道(本发明实施例的专用时间时钟通道为在面板上的一条物理传输线路)传送过来的，也可以包括时间时钟传输模块30通过专用通过传送过来的。时钟信息进入时钟处理单元21，时钟处理单元21根据软件SSM算法，从多路时钟源中选出一路优先级最高或时钟质量等级最高的有效时钟输出给SEC单元23，SEC单元23根据输入的时钟进行锁定，然后输出设备所需的多路不同频率的时钟，输出的时钟与时钟/时间提取单元提取的时钟为同源 钟，这样整个设备的时钟通过SEC单元23完成了时钟同步。时间信息的处理，是时间处理单元22对传送过来的PTP报文或1PPS及TOD信息进行处理。如果接收的是PTP报文，则根据报文里传送过来的时间戳信息，依靠BMC算法，进行本地1588时间的对时功能，本地时间对时后，再对发送的PTP报文打上本地时间戳传送出去。如果接收的是1PPS及TOD，则根据TOD帧格式，与1PPS信号锁存的时间处理单元22内部的时间戳进行校正，实现本地时间信息的校准后，再将本地时间信息封装到TOD帧格式中，将TOD帧与对应的1PPS信号传送出去。
在本实施例中，通过在时间时钟处理模块20设置时间处理单元22、时钟处理单元21以及分别与时间处理单元22和时钟处理单元21连接的同步设备时钟SEC单元23，通过时钟处理单元21选出优先级最高的最佳时钟并传输给SEC单元23，SEC单元23基于有效时钟和时钟频率同步OTN网元设备的时钟；时间处理单元基于PTP报文和1PPS及TOD报文中的时间戳对OTN网元设备进行时间校准，从而实现OTN网元设备时间和时钟的同步。
本发明实施例还提供一种OTN时钟和时间的同步方法，在本发明OTN时钟和时间的同步方法的第一实施例中，参照图3，该OTN时钟和时间的同步方法包括：
步骤10，OTN网元设备根据其所在网络的链路类型，确定时间时钟传输方案，并从该时间时钟传输方案对应的业务端口和/或面板接口中提取时间信息和时钟信息。本发明实施例，可以在接收到时间时钟同步指令时实施，即OTN网元设备接收到时间时钟同步指令时实施。
在OTN需要进行时间时钟同步时,OTN网元设备从其业务端口或面板接口中提取出时间信息和时钟信息。OTN网元设备所在网络的链路类型包括OTN业务链路、光监控通道、时钟线缆链路、光口电口链路等，链路类型总体分为带外传输类型和带内传输类型，时间时钟传输方案大致包括三种，第一种：在OTN网元设备所在网络的链路类型为带外传输类型，时间时钟传输方案提供带内传输通道；第二种：在OTN网元设备所在网络的链路类型为带内传输类型，时间时钟传输方案提供带外传输通道；第三种：无论OTN网元 设备所在网络的链路类型是什么，时间时钟传输方案同时提供带内传输通道和带外传输通道。带内传输通道对应业务端口，带外传输通道对应面板接口。
业务端口包括多种同步以太网端口(例如FE(Fast Ethernet，快速以太网或百兆以太网)端口、GE(Gigabit Ethernet，千兆以太网)端口、10GE(10Gigabit Ethernet，万兆以太网)端口等)，以及OTN业务端口等，面板接口包括1PPS及TOD(1PPS(1Pulse Second，秒脉冲)，TOD(Time of Day，日时间常数))端口和2MHz/2Mbists时钟接口等。本发明提及的1PPS及TOD标准协议是指中国移动通信企业标准QB-B-016-2010《中国移动高精度时间同步1PPS及TOD接口规范》)。时钟信息包括SSM(Synchronization Status Message，同步状态信息)和时钟频率，时间信息包括PTP((Precision Time Protocol，精确时间协议)报文和IPPS及TOD报文。
步骤20，OTN网元设备根据提取的时钟信息完成本地的时钟同步，根据提取的时间信息校准本地的时间；
OTN网元设备根据时钟信息中的SSM，从多路时钟源中选出一路优选级最高或时钟质量等级最高的有效时钟输出给预设于该OTN网元设备中的SEC(Sychronous equipment clock，同步设备时钟)单元，SEC单元根据输入的时钟进行锁定，然后输出OTN网元设备所需的多路不同频率的时钟，并根据时钟信息中的时钟频率同步整个OTN网元设备的时钟。同时，OTN网元设备对接收的时间信息进行处理，当接收的时间信息为PTP报文，则根据报文里传送过来的时间戳信息和BMC(Best Master Clock algorithm，最佳主时钟算法)，进行OTN网元设备本地1588时间的对时功能；当接收的时间信息为1PPS及TOD报文时，则根据1PPS及TOD报文中的TOD帧格式1PPS信号中锁存的时间戳进行校正，从而实现OTN网元设备本地时间信息的校准。
步骤30，OTN网元设备根据确定的时间时钟传输方案，选择预设的带内传输通道或预设的带外传输通道将校准后的时间信息和完成同步的时钟信息传输至下一级OTN网元设备。
可选地，预设的带内传输通道包括线路侧业务传输通道和电口光口通道，所述预设的带外传输通道包括光监控通道OSC和时钟线缆通道。
OTN网元设备提供四种传输方案：第一种是通过线路侧的OTN业务将 时钟/时间信息传递给下一个OTN网元设备，这种方案属于带内传输。以OTN的保留开销为载体，配合物理层时钟同步，传递经过GFP封装的PTP报文或SSM信息，在下一个OTN网元的时钟/时间提取单元中解出时钟/时间信息，实现时钟/时间同步；第二种是通过OSC通道传(Optical Supervisory Channel，光监控通道)送时钟/时间信息，这种方案属于带外传输。OSC通道包括OSC单元和光纤通道。OSC单元内部提供满足EEC 3级时钟标准的时钟处理单元和同步以太网物理层器件，在OSC的波长上建立同步以太网，通过同步以太网传递时钟SSM信息，配合以太网的恢复钟，实现时钟同步。在满足时钟同步的条件下，提供以太网端口的1588数据包的交互以实现所有节点的时间同步。OSC通道采用单纤双向的传输方式，可以消除或者减少PTP端口的收发延时不对称，以实现无需逐点校正不对称延时的功能；第三种是通过面板外部接口经过线缆传送时钟/时间信息，这种方案也属于带外传输。其中面板外部接口包括支持中移动1PPS及TOD的标准协议的电口，用于传送时间信息，和支持2MHz/2MBits时钟的电口，用于传送时钟频率；第四种是通过FE/GE/10GE的电口/光口传送时钟/时间信息，这种方案属于带内传输。将本地时间封装到PTP报文中，然后通过FE/GE/10GE的电口/光口传送给其他节点，时钟的SSM信息则通过从节点的以太网芯片从数据中解析出来，从而实现时钟/时间同步。
在本实施例中，通过在OTN网元设备中设置同时包括带内传输通道和带外传输通道的时间时钟传输模块，并根据OTN网元设备所在网络的链路类型，确定时间时钟传输方案，再根据时间时钟传输方案选择带内传输通道或者带外传输通道将接收的时间信息和时钟信息传输至下一级OTN网元设备，并且在OTN网元设备中设置可接收带内传输通道传输的时间时钟信息的业务端口和可接收带外传输通道传输的时间时钟信息的面板接口，从而使得本发明实施例OTN网元设备同时支持带内传输和带外传输，本发明实施例OTN网元设备可以连接于由仅支持带内传输或仅支持带外传输的OTN网元设备组成的相关技术的OTN中，使带内传输和带外传输相结合，从而时钟/时间信息可以顺利地从相关技术中的OTN网元设备传输到本发明实施例的OTN网元设备，也可以顺利地从本发明实施例的OTN网元设备传输至相关技术中的OTN网元设备中，从而充分利用相关技术中的OTN网元设备来传送时钟/ 时间信息，节省了重新组网的成本。
可选地，在本发明OTN时钟和时间的同步方法第一实施例的基础上，提出本发明OTN时钟和时间的同步方法的第二实施例，在第二实施例中，步骤10包括：
步骤11，OTN网元设备从业务端口传出的业务信号中提取时钟频率和同步状态信息(SSM)作为时钟信息，或者从面板时钟源接口传输的信号中提取时钟频率和SSM作为时钟信息；
OTN网元设备是从每一个时钟源中提取中时钟信息，一种是从业务信号中恢复出时钟频率，并从业务信息的业务开销中提取出SSM，这种方式属于带内传送方式；另一种是从面板时钟源接口传输过来的信号中直接提取出时钟频率和SSM，这种方式属于带外传送方式。
步骤12，OTN网元设备从业务端口和/或面板接口中提取精确时间协议(PTP)报文或秒脉冲(1PPS)及日时间常数(TOD)报文。
可选地，步骤12包括：
步骤121，当OTN网元设备从业务端口或面板接口中提取的报文为PTP报文时，若所述OTN网元设备为主节点设备，则在该提取的PTP报文中添加OTN网元设备的时间戳，将添加时间戳的PTP报文作为时间信息；若OTN网元设备为从节点设备，将PTP报文作为时间信息；
本发明实施例可以记录提取的PTP报文中的时间戳后，再将PTP报文中作为时间信息发送
步骤122，当所述OTN网元设备从业务端口或面板接口中提取的报文为1PPS及TOD报文时，获取1PPS及TOD报文中的同步定时信息，将获取的同步定时信息作为时间信息。
OTN网元设备是从每一个时间来源中提取出时间信息，OTN网元设备从业务端口或面板接口中提取出PTP报文或1PPS及TOD报文。如果接收的报文为PTP报文，则在其报文尾部打上时间戳并重新进行CRC校验(Cyclic Redundancy Check，循环冗余校验码)；如果接收的报文为1PPS及TOD，则根据TOD帧格式提取出同步定时信息。如果要发送PTP报文，则需根据设 备的主从关系分别进行报文的处理，如果本OTN网元设备是主节点，则在PTP报文中打上本设备时间戳，并重新组成PTP报文发送出去；如果本OTN网元设备是从节点，则记录PTP报文里的时间戳，然后把这个时间戳送给软件进行本板时间的修正。如果发送的是1PPS及TOD报文，则将GPS信息封装到TOD帧里，将TOD帧与对应的1PPS信号传送出去。
此外，OTN网元设备也可以从专用时钟/时间通道中提取出时钟时间信息，通过OTN网元设备的业务端口或面部接口将时钟时间信息传送出去。其中业务端口包括相关技术中的同步以太网端口(FE百兆以太网/GE千兆以太网/10GE，以及40GE，100GE和未来的400GE等)，还包括OTN业务端口；面板接口包括1PPS及TOD端口，还有2MHz/2MBits时钟接口等。
在本实施例中，通过带内和带外两种传送方式提取时钟频率和SSM以同步OTN网元设备本地时钟，并通过带内和带外两种传送方式提取PTP报文或1PPS及TOD报文以对OTN网元设备本地时间进行校准，从而OTN网元设备能够支持提取上一个网元设备通过带内传输通道或者带外传输通道传送的时间时钟信息。
可选地，在本发明OTN时钟和时间的同步方法第二实施例的基础上，提出本发明OTN时钟和时间的同步方法的第三实施例，在第三实施例中，步骤20包括：
步骤21，OTN网元设备接收到时钟信息时，根据时钟信息中的SSM获取最佳时钟，并根据最佳时钟和时钟信息中的时钟频率完成整个OTN网元设备的时钟同步。
步骤22，OTN网元设备接收到的时间信息包括PTP报文时，根据接收的PTP报文中的时间戳校准所述OTN网元设备的时间；或者，
步骤23，OTN网元设备接收到的时间信息包括1PPS及TOD报文时，根据该1PPS及TOD报文中的同步定时信息校准所述OTN网元设备的时间。
OTN网元设备对传输进来的时钟时间信息进行处理，时钟时间的来源可以是OTN网元设备通过专用时间时钟通道(本发明所指的专用时间时钟通道 为在面板上的一条物理传输线路)传送过来的，也可以是OTN网元设备通过专用通过传送过来的。时钟信息进入OTN网元设备后，OTN网元设备根据软件SSM算法，从多路时钟源中选出一路优先级最高或时钟质量等级最高的有效时钟输出给SEC单元，SEC单元根据输入的时钟进行锁定，然后输出设备所需的多路不同频率的时钟，输出的时钟与时钟/时间提取单元提取的时钟为同源钟，这样整个设备的时钟通过SEC单元23完成了时钟同步。时间信息的处理，是OTN网元设备对传送过来的PTP报文或1PPS及TOD信息进行处理。如果接收的是PTP报文，则根据报文里传送过来的时间戳信息，依靠BMC算法，进行本地1588时间的对时功能，本地时间对时后，再对发送的PTP报文打上本地时间戳传送出去。如果接收的是1PPS及TOD，则根据TOD帧格式，与1PPS信号锁存的OTN网元设备内部的时间戳进行校正，实现本地时间信息的校准后，再将本地时间信息封装到TOD帧格式中，将TOD帧与对应的1PPS信号传送出去。
在本实施例中，通过在OTN网元设备中设置SEC单元，通过选出优先级最高的有效时钟并传输给SEC单元，SEC单元基于有效时钟和时钟频率同步OTN网元设备的时钟；基于PTP报文和1PPS及TOD报文中的时间戳对OTN网元设备进行时间校准，从而实现OTN网元设备时间和时钟的同步。
本发明实施例还提供一种计算机存储介质，计算机存储介质中存储有计算机可执行指令，所述计算机可执行指令用于执行上述OTN时钟和时间的同步方法。
本发明实施例还提供一种OTN时钟和时间的同步系统，OTN时钟和时间的同步系统包括两个或两个互相连接组成环型网络的OTN网元设备、PTN(Packet Transport Network，分组传送网)设备和BITS，所述PTN设备与所述环型网络中连接，所述环型网络中OTN网元设备与BITS连接。其中PTN设备与多个基站连接，将与BITS连接的OTN网元设备作为主站点。
为了更好理解本发明实施例OTN时钟和时间的同步方法和系统，以下以城域网为例进行实施例的描述，参照图5，以城域网为例进行实施例的描述。 城域网接入层属于新旧传输网络交替期，为了解决日益增加的带宽需求，这就要求接入层能够满足Any-Rate-Service(多业务接入)，能够有边缘层OTN网络与核心层OTN网络实现端到端传送，还要求能够满足长距离、大带宽的传送。目前现网中存在大量的SDH/PTN的设备(SDH(Synchronous Digital Hierarchy，同步数字体系)，PTN(分组传送网，Packet Transport Network))，SDH/PTN设备不仅支持多业务承载，还能够支持全网时钟/时间同步功能。对于经过SDH/PTN设备汇聚后的业务，在OTN网络中进行传输，也需要考虑时钟/时间同步功能。
在示例一中，OTN网元设备A、B、C、D四个站点组成了一个OTN环网，客户侧接入PTN业务，其中虚线网络代表时钟/时间同步传送网络。C站点作为主站点(或称主节点)，接入BITS(Building Integrated Timing Supply System，数字通信时间频率同步供给系统)。BITS内置GPS接收机及晶体震荡单元，可以配置产生一级钟，二级钟和三级钟，并带有外时钟接口，可以提供2MHz/2MBits的输出，以及时钟SSM信息的提取和生成；BITS通过GPS接收机接收卫星定时信号，经过板内时间戳提取和生成等处理后从面板接口(FE/GE/10GE光口/电口，或1PPS及TOD电口)输出时间信息。
C站点通过BITS的2MHz/2MBits外时钟接口和1PPS及TOD电口，接收到时钟/时间信息，进入C站点进入时间时钟提取模块提取出时钟时间信息。如图1和2所示，时间时钟提取模块将时钟/时间信息提取出来，并从面板2MHz/2MBits外时钟源接口传输过来的信号中直接提取出时钟频率和SSM信息，然后通过专用通道送到时间时钟处理模块。时钟信息进入到时间时钟处理模块后，时间时钟处理模块根据软件SSM算法，从这路时钟源输出给SEC单元，SEC单元锁定在输入的时钟上，然后SEC单元输出设备所需的多路不同频率的时钟，C站点设备的时钟通过SEC单元完成了时钟同步，即C站点输出的业务时钟、设备内部运行的系统钟等都是与BITS输出的时钟同源的钟。C站点的时间时钟处理模块将时钟SSM信息封装到线路侧的OTUk的保留开销中，以OTN的保留开销为载体，配合业务恢复时钟的传输，通过时间时钟传输模块传递到B站点。而时间信息则是从1PPS及TOD电口，由时间时钟提取模块根据TOD帧格式提取出同步定时信息。时间时钟提取模块将本 地GPS信息封装到TOD帧里，将TOD帧与对应的1PPS信号传送到时间时钟处理模块，根据TOD帧格式，与1PPS信号锁存的时间时钟处理模块内部的时间戳进行校正，实现本地时间信息的校准后，再将本地时间信息封装到TOD帧格式中，将TOD帧与对应的1PPS信号传送到时间时钟传输模块，时间时钟传输模块通过1PPS及TOD电口线缆通道传递到B站点的1PPS及TOD的电口接口。B站点的处理流程和C站点相同，同样经过了时间时钟提取模块和时间时钟处理模块实现了B站点内的时钟同步，以及和C站点的时间同步，并通过时间时钟传输模块将时钟时间信息传递到A站点。A站点的处理流程也和C站点相同，同样经过了时间时钟提取模块和时间时钟处理模块实现了A站点内的时钟同步，以及和B、C站点的时间同步，然后A站点通过时间时钟传输模块中的客户侧的GE同步以太网业务将时钟时间信息向下传递给PTN设备，PTN设备从GE同步以太网业务中提取出时钟/时间信息，经过处理后，分发给每一个基站。这样就实现了OTN和PTN网络的时钟/时间同步。
在示例二中，OTN网元设备A、B、C、D四个站点组成了一个OTN环网中有独立的OSC通道，在提供监控光传输功能的同时，也可以利用OSC通道传输时钟/时间信息。具体实施方案如下：C站点时间时钟提取模块和时间时钟处理模块的处理方式与示例一相同，不同的是示例二不通过线路侧开销进行时钟/时间信息的传递，而是C站点时间时钟传输模块选择通过OSC光纤通道将时钟时间信息传递到B站点(如图5中C、B站点间的虚线网络)。进入OSC光纤通道前，OSC单元通过GE同步以太网向B站点传递时钟SSM信息和业务恢复时钟，实现C、B站点的时钟同步。在满足时钟同步的条件下，OSC单元提供GE同步以太网端口的1588V2数据包的交互以实现C、B站点间的时间同步。B站点的OSC单元接收到光纤通道传送过来的信息，进入时间时钟提取模块、时间时钟处理模块实现了B站点内的时钟同步，以及和C站点的时间同步，并通过时间时钟传输模块中的OSC通道将时钟时间信息传递到A站点。A站点的处理流程和B站点相同，同样经过了时间时钟提取模块和时间时钟处理模块实现了A站点内的时钟同步，以及和B、C站点的时间同步，然后A站点通过时间时钟传输模块中的客户侧的GE同步以太网业务将时钟时间信息向下传递给PTN设备，PTN设备从GE同步以太网业 务中提取出时钟/时间信息，经过处理后，分发给每一个基站。这样就实现了OTN和PTN网络的时钟/时间同步。
为了减少OTN网络传输过程中时延的不确定性，在示例三中，如图6所示，引入独立的时钟/时间传送网络，虚线所代表的就是独立的时钟/时间传送网络。以C站点作为主站点，C站点的时间时钟提取模块通过BITS的2MHz/2MBits外时钟接口和1PPS及TOD电口，提取出时钟/时间信息，进行时钟/时间信息的处理后，通过独立的时钟/时间传送网络传递给A、B、D三个站点的时间时钟提取模块，实现ABCD组成的环网的时钟/时间同步。独立的时钟/时间传送网络包括不仅限于以下几种形式：用于传送2MHz/2MBits时钟线缆网络，传输1PPS及TOD信息的电口线缆网络，还有传输以太网FE/GE/10GE的光纤网络，或者是以太网FE/GE/10GE的电口线缆网络等。从而实现高精度的环网时钟/时间同步。
本领域普通技术人员可以理解上述方法中的全部或部分步骤可通过程序来指令相关硬件(例如处理器)完成，所述程序可以存储于计算机可读存储介质中，如只读存储器、磁盘或光盘等。可选地，上述实施例的全部或部分步骤也可以使用一个或多个集成电路来实现。相应地，上述实施例中的每个模块/单元可以采用硬件的形式实现，例如通过集成电路来实现其相应功能，也可以采用软件功能模块的形式实现，例如通过处理器执行存储于存储器中的程序/指令来实现其相应功能。本发明不限制于任何特定形式的硬件和软件的结合。
虽然本申请所揭露的实施方式如上，但所述的内容仅为便于理解本申请而采用的实施方式，并非用以限定本申请，如本发明实施方式中的具体的实现方法。任何本申请所属领域内的技术人员，在不脱离本申请所揭露的精神和范围的前提下，可以在实施的形式及细节上进行任何的修改与变化，但本申请的专利保护范围，仍须以所附的权利要求书所界定的范围为准。
工业实用性
上述技术方案利用OTN网元设备实现了时钟和时间信息的传送。

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  1. 一种光传输网OTN网元设备，所述OTN网元设备包括：时间时钟提取模块、时间时钟处理模块和时间时钟传输模块，所述时间时钟处理模块通过专用时间时钟通道分别与所述时间时钟提取模块和时间时钟传输模块连接，
    所述时间时钟提取模块设置为，根据所述OTN网元设备所在网络的链路类型，确定时间时钟传输方案；从所述时间时钟传输方案对应的业务端口和/或面板接口中提取出时间信息和时钟信息，并将提取的时间信息和时钟信息经专用时间时钟通道发送至所述时间时钟处理模块；
    所述时间时钟处理模块设置为，接收到所述时钟信息时，根据接收到的时钟信息完成所述OTN网元设备的时钟同步；接收到所述时间信息时，根据接收到的时间信息校准所述OTN网元设备的时间；并将处理后的时钟信息和时间信息经专用时间时钟通道发送至所述时间时钟传输模块；
    所述时间时钟传输模块包括带内传输通道和带外传输通道，设置为根据时间时钟提取模块确定的时间时钟传输方案，选择带内传输通道或带外传输通道将接收的由时间时钟处理模块处理后的时间信息和时钟信息传输至下一级OTN网元设备。
  2. 如权利要求1所述的OTN网元设备，其中，所述时间时钟提取模块包括时钟提取单元和时间提取单元，
    所述时钟提取单元，设置为从业务端口传出的业务信号中提取时钟频率和同步状态信息SSM，或者从面板时钟源接口传输的信号中提取时钟频率和SSM，并将提取的时钟频率和SSM作为所述时钟信息传输至所述时间时钟处理模块；
    所述时间提取单元，设置为从业务端口和/或面板接口中提取精确时间协议PTP报文或秒脉冲1PPS及日时间常数TOD报文，并将提取的PTP报文或1PPS及TOD报文作为时间信息传输至所述时间时钟处理模块。
  3. 如权利要求2所述的OTN网元设备，其中，所述时间提取单元是设置为：
    当提取的报文包括PTP报文时，若所述OTN网元设备为主节点设备，则在该提取的PTP报文中添加所述OTN网元设备的时间戳，并将添加时间戳的PTP报文作为所述时间信息传输至所述时间时钟处理模块；若所述OTN网元设备为从节点设备，将该PTP报文作为所述时间信息传输至所述时间时钟处理模块；
    当提取的报文包括1PPS及TOD报文时，获取1PPS及TOD报文中的同步定时信息，并将获取的该同步定时信息作为所述时间信息发送至所述时间时钟处理模块。
  4. 如权利要求3所述的OTN网元设备，其中，所述时间时钟处理模块包括时间处理单元、时钟处理单元以及分别与所述时间处理单元和时钟处理单元连接的同步设备时钟SEC单元，
    所述时钟处理单元设置为，接收到时钟信息时，根据时钟信息中的SSM获取最佳时钟，并将所述最佳时钟和所述时钟信息中的时钟频率传输至所述SEC单元以完成整个所述OTN网元设备的时钟同步；将接收的所述时钟信息发送至所述时间时钟传输模块；
    所述时间处理单元设置为，接收到的时间信息包括PTP报文时，根据接收的PTP报文中的时间戳，校准所述OTN网元设备的时间，并在接收的PTP报文添加所述OTN网元设备校准后时间，并将添加校准后时间的PTP报文传输至所述时间时钟传输模块；接收到的时间信息包括1PPS及TOD报文时，根据所述1PPS及TOD报文中的同步定时信息校准所述OTN网元设备的时间，并将封装有所述校准后时间的1PPS及TOD报文传输至所述时间时钟传输模块。
  5. 如权利要求1至4任意一项所述的OTN网元设备，其中，所述预设的带内传输通道包括线路侧业务传输通道和电口光口通道，所述预设的带外传输通道包括光监控通道OSC和时钟线缆通道。
  6. 一种OTN时钟和时间的同步方法，所述同步方法包括：
    OTN网元设备根据其所在网络的链路类型，确定时间时钟传输方案，并从该时间时钟传输方案对应的业务端口和/或面板接口中提取时间信息和时 钟信息；
    所述OTN网元设备根据提取的所述时钟信息完成本地的时钟同步，根据提取的所述时间信息校准本地的时间；
    所述OTN网元设备根据确定的所述时间时钟传输方案，选择预设的带内传输通道或预设的带外传输通道将校准后的时间信息和完成同步的时钟信息传输至下一级OTN网元设备。
  7. 如权利要求6所述的同步方法，其中，所述提取时间信息和时钟信息包括：
    所述OTN网元设备根据所述时间时钟传输方案确定提取时间时钟信息的业务端口和/或面板接口；
    所述OTN网元设备从所述业务端口传出的业务信号中提取时钟频率和同步状态信息SSM作为所述时钟信息，或者从面板时钟源接口传输的信号中提取时钟频率和SSM作为所述时钟信息；
    所述OTN网元设备从所述业务端口和/或面板接口中提取精确时间协议PTP报文或秒脉冲1PPS及日时间常数TOD报文作为时间信息。
  8. 如权利要求7所述的同步方法，其中，所述从所述业务端口或面板接口中提取PTP报文或1PPS及TOD报文包括：
    当所述OTN网元设备从业务端口和/或面板接口中提取的报文为PTP报文时，若所述OTN网元设备为主节点设备，则在该提取的PTP报文中添加所述OTN网元设备的时间戳，将添加时间戳的PTP报文作为所述时间信息；若所述OTN网元设备为从节点设备，将该PTP报文作为所述时间信息；
    当所述OTN网元设备从业务端口和/或面板接口中提取的报文为1PPS及TOD报文时，获取1PPS及TOD报文中的同步定时信息，将获取的同步定时信息作为所述时间信息。
  9. 如权利要求8所述的同步方法，其中，所述OTN网元设备根据所述时钟信息完成本地的时钟同步，根据所述时间信息校准本地的时间包括：
    所述OTN网元设备接收到时钟信息时，根据时钟信息中的SSM获取最佳时钟，并根据所述最佳时钟和所述时钟信息中的时钟频率完成整个OTN网 元设备的时钟同步；
    所述OTN网元设备接收到的时间信息包括PTP报文时，根据接收的PTP报文中的时间戳校准所述OTN网元设备的时间；或者，所述OTN网元设备接收到的时间信息包括1PPS及TOD报文时，根据该1PPS及TOD报文中的同步定时信息校准所述OTN网元设备的时间。
  10. 如权利要求6至9任意一项所述的同步方法，其中，所述预设的带内传输通道包括线路侧业务传输通道和电口光口通道，所述预设的带外传输通道包括光监控通道OSC和时钟线缆通道。
  11. 一种OTN时钟和时间的同步系统，所述OTN时钟和时间的同步系统包括两个或两个以上互相连接组成环型网络的OTN网元设备、分组传输网PTN设备和数字通信时间频率同步供给系统BITS，所述PTN设备与所述环型网络中连接，所述环型网络中OTN网元设备与所述BITS连接。
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