CN106685565A - Method and system for achieving transparent clock transmission of communication network - Google Patents

Method and system for achieving transparent clock transmission of communication network Download PDF

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CN106685565A
CN106685565A CN201611251477.2A CN201611251477A CN106685565A CN 106685565 A CN106685565 A CN 106685565A CN 201611251477 A CN201611251477 A CN 201611251477A CN 106685565 A CN106685565 A CN 106685565A
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China
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device
onu
clock
packet
olt
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CN201611251477.2A
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朱玛
李勇
金乃正
姚树建
余杰
盛海华
沈祥
许海峰
马平
王悦
钱宏
钱一宏
余新生
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国网浙江省电力公司绍兴供电公司
国家电网公司
国网浙江省电力公司
杭州晨晓科技股份有限公司
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Priority to CN201611251477.2A priority Critical patent/CN106685565A/en
Publication of CN106685565A publication Critical patent/CN106685565A/en

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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B10/00Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25Arrangements specific to fibre transmission
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J3/00Time-division multiplex systems
    • H04J3/02Details
    • H04J3/06Synchronising arrangements
    • H04J3/0602Systems characterised by the synchronising information used
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J3/00Time-division multiplex systems
    • H04J3/02Details
    • H04J3/06Synchronising arrangements
    • H04J3/0635Clock or time synchronisation in a network
    • H04J3/0638Clock or time synchronisation among nodes; Internode synchronisation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00Application independent communication protocol aspects or techniques in packet data networks
    • H04L69/06Notations for structuring of protocol data, e.g. abstract syntax notation one [ASN.1]

Abstract

The invention discloses a method and a system for achieving transparent clock transmission of a communication network. The method comprises following steps of 1), using a time synchronization feature of an EPON system, virtualizing an OLT device and an ONU device into one synchronization system device and simplifying a system transparent clock transmission process; 2), adding a timestamp field to the tail of a synchronization report so as to allow an entrance timestamp of the synchronization report to be carried to a device exit; and 3), according to the correction residence time obtained by the synchronization system device, the P2P range finding between a master clock device and a physical port of the OLT device and the P2P range finding between a slave clock device and a physical port of the ONU device, obtaining the time difference of transmission of the synchronization report from the master clock device to the slave clock device. According to the invention, a problem is solved that P2P range finding and residence time correction are not supported between the PON port of the OLT device and the PON port of the ONU device.

Description

一种实现通信网络透明时钟传递的方法及系统 A method in a communication network and to achieve transparent transfer system clock

技术领域 FIELD

[0001] 本发明涉及一种实现通信网络透明时钟传递的方法及系统,属于智能电网技术领域。 [0001] The present invention relates to a method and system for realizing a communication network transparent transfer clock, belonging to the technical field of smart grids.

背景技术 Background technique

[0002] IEEE 1588 verison2精确时钟同步协议详细定义了透明时钟(transparentclock)的实现方法。 [0002] IEEE 1588 verison2 precision clock synchronization protocol defines in detail transparent clock (transparentclock) implementation. 如图1所示,主时钟设备要把1588时间传递给从时钟设备,那么主时钟设备和从时钟设备间要互相收发1588时间同步报文(时间同步报文传递路径1,时间同步报文传递路径2)。 1, the master clock device 1588 should transfer to the time from the clock device, then the master clock device and the slave clock device to send and receive between each 1588 time synchronization packet (time synchronization packet transmission path 1, the time synchronization message delivery path 2). 同时,处于主时钟设备和从时钟设备间的通信网络设备需要逐级对经过它们的特定1588报文做出驻留时间修改,即需要计算报文进通信网络设备物理端口时刻与报文出通信网络设备物理端口时刻的差值,然后把差值补偿到1588时间同步报文中。 Meanwhile, in the master clock device and the slave device communication between network clock device needs to be made progressively modified residence time 1588 through their specific packets, i.e. packets need to calculate the physical port into communication network device and timing of a communication packet the time difference between the physical ports of the network device and then compensating the difference value to 1588 in the time synchronization packet. 透明时钟分为end-to-end (E2E) TC和peer-to-peer (P2P) TC,如果采用的是P2P TC,那么从时钟设备与ONU设备间、ONU设备和OLT设备间(0DN是无源设备,等价于光纤,时延固定)、0LT设备和主时钟设备间都要做P2P的测距工作,计算每一段光纤的固定延时。 Transparent Clock divided into end-to-end (E2E) TC, and peer-to-peer (P2P) TC, if the P2P TC, then from between the clock device and the ONU between the OLT and the ONU (0DN is no source device, equivalent to the optical fiber, the fixed delay), between the device and the master clock device 0LT have to do work ranging P2P, the fixed delay is calculated for each segment of the optical fiber. 如图1所示,ONU设备修正驻留时间Δ tl,OLT设备修正驻留时间Δ t2。 1, ONU residence time correction apparatus Δ tl, OLT device for modifying the residence time Δ t2. P2P测距1、P2P测距2、P2P测距3。 P2P ranging 1, P2P ranging 2, P2P ranging 3. 采用上述方法,主要存在如下缺陷: With the above method, there is a major flaw:

1)由于EPON采用单芯光纤,上下行波长不同导致延时不同。 1) Since the EPON uses a single fiber, different wavelengths result in different uplink and downlink delay. P2P测距时需要根据实际光纤长度来补偿上下行的延时差,否则会影响P2P测距的精度,从而影响1588时间同步精度; P2P ranging needs to be compensated according to the actual length of the fiber delay difference down the line, otherwise it will affect the accuracy of the ranging P2P, thereby affecting the accuracy of time synchronization 1588;

2) OLT和ONU之间是通过分光器点对多点连接的,同一个OLT物理端口至多可以和128个ONU的物理端口连接。 2) between the OLT and the ONU are connected through a multipoint beam splitter, the same physical port up OLT may be connected to physical port 128 and the ONU. 那么OLT端需要跟128个ONU的端口分别进行P2P测距,对OLT而言设计难度很大; The OLT side needs with port 128 of the P2P ONU ranging respectively, in terms of OLT great design difficulty;

3) 1588时间同步过程中,中间节点越多,引入的驻留时间修正误差越大,从而导致同步精度降低。 3) 1588 time synchronization, the more the intermediate node, the greater the dwell time of the introduction of errors corrected, resulting in reduced accuracy of synchronization.

[0003] 有鉴于此,本发明人对此进行研究,专门开发出一种实现通信网络透明时钟传递的方法及系统,本案由此产生。 [0003] In view of this, the present invention is to study this, a specially developed method and system in a communication network implemented in a transparent transmission clock, thereby generating the case.

发明内容 SUMMARY

[0004] 本发明的目的是提供一种实现通信网络透明时钟传递的方法及系统,解决OLT设备和ONU设备PON 口间不支持P2P测距以及驻留时间修正的问题。 [0004] The object of the present invention is to provide a method and system for a communication network to achieve transparent transfer clock, does not solve the problem P2P support and distance between the OLT and the ONU PON port dwell time correction.

[0005] 为了实现上述目的,本发明的解决方案是: [0005] To achieve the above object, the present invention is a solution:

一种实现通信网络透明时钟传递的方法,包括如下步骤: A method for a communication network to achieve transparent transfer clock, comprising the steps of:

步骤I)、利用EPON系统的时间同步特性,将OLT设备和ONU设备虚拟为一台同步系统设备,简化系统传递透明时钟过程; The I step), using the time synchronization feature of the EPON system, the OLT device and the ONU is a synchronous system virtual equipment, simplifying the system clock transparent transfer process;

步骤2)、在同步报文尾部添加时戳字段,使同步报文入口时戳能携带到设备出口(0LT-ONU之间); 步骤3)、根据同步系统设备得到的修正驻留时间、主时钟设备和OLT设备物理口之间的P2P测距、以及从时钟设备与ONU设备物理口之间的P2P测距,得到同步报文从主时钟设备传递到从时钟设备的时间差。 Step 2), the time stamp field in the packet sync adding tail, so that the synchronization timestamp packets can carry the inlet to the outlet device (0LT-ONU between); Step 3), the residence time synchronization system according to the modified device obtained, the main P2P distance between the OLT and clock device physical interface, as well as from the P2P clock device and the distance between the ONU physical port, synchronized packet transmitted from the master clock device to time difference from a clock device.

[0006]作为优选,所述步骤2)具体过程为:需要计算报文驻留时间的同步报文进入OLT设备的物理端口时,在端口的PCS层或者MAC层记录下OLT设备的MPCP钟表值(S卩入口时戳),并把钟表值附带到该报文的尾部;当该报文转发到ONU设备后,提取报文尾部的入口时戳,并在该报文转发到ONU设备与从时钟设备相连的物理口时,在端口PCS层或者MAC层记录下ONU设备的MPCP钟表值(即出口时戳,修正RTT/2)。 [0006] Advantageously, the step 2) specific process: when packets need to calculate the dwell time of the synchronization packet physical port of the OLT equipment, watches and clocks, the value of the MPCP in the OLT port PCS layer or the MAC layer of the recording (S Jie inlet stamp), and the value of the watch comes to the tail of the packet; when forwards the packets to the ONU, extracting timestamp inlet end of packet, and forwards the packets to and from the ONU when a physical port connected to the clock device, (i.e. timestamp outlet, corrected RTT / 2) values ​​in the ONU MPCP port timepiece PCS recording layer or the MAC layer. 该报文的驻留时间等于出口时戳减去入口时戳(二进制无符号减法),并把驻留时间填到相应的报文correct1nField域中。 Subtracting the time stamp entry timestamp is equal to the residence time of the packet outlet (binary unsigned subtraction), and the residence time to fill the respective packets correct1nField domain.

[0007] 作为优选,当工作在P2P TC时,从时钟设备和ONU设备物理口、主时钟设备和OLT设备物理口之间的P2P测距按照1588v2的协议来实现。 [0007] Preferably, when operating in P2P TC, the slave clock device and the ONU physical port, P2P device ranging between the master clock and the OLT according to the protocol physical port 1588v2 be implemented.

[0008]作为优选,所述OLT设备和ONU设备内部涉及到的时戳计数器,采用各自的32位二进制MPCP时戳计数器。 [0008] Advantageously, when the internal device OLT and ONU counters apparatus related to the stamp, each timestamp counter using 32-bit binary MPCP.

[0009] 作为优选,所述ONU设备上采用独立的32位二进制freerun计数器,这样ONU MPCP计数器的几十纳秒误差不会引入到ONU设备的P2P测距中。 [0009] Advantageously, the ONU independent freerun 32-bit binary counter on the device, so that an error of tens of nanoseconds ONU does not introduce into the MPCP counter P2P ranged ONU apparatus.

[0010] 一种实现通信网络透明时钟传递的系统,包括: [0010] A communication network system to achieve transparent transfer clock, comprising:

报文时戳处理模块:在同步报文尾部添加时戳字段,使同步报文入口时戳携带到设备出口; When the packet processing module timestamp: timestamp field in the synchronous packet tail addition the outlet device to carry stamp synchronization packet entry;

报文时差处理模块:根据同步系统设备得到的修正驻留时间、主时钟设备和OLT设备物理口之间的P2P测距、以及从时钟设备与ONU设备物理口之间的P2P测距,计算同步报文从主时钟设备传递到从时钟设备的时间差。 Packet processing module difference: the dwell time synchronization system according to the modified device obtained, P2P device ranging between the master clock and the OLT physical interface, as well as from the P2P clock device and the distance between the ONU physical port, calculates a synchronization message transmitted from the main device to the clock from the clock device time difference.

[0011]作为优选,所述报文时差处理模块被设置为,计算报文驻留时间的同步报文进入OLT设备的物理端口时,在端口的PCS层或者MAC层记录下OLT设备的MPCP钟表值,即入口时戳,并把钟表值附带到该报文的尾部;当该报文转发到ONU设备后,提取报文尾部的入口时戳,并在该报文转发到ONU设备与从时钟设备相连的物理口时,在端口PCS层或者MAC层记录下ONU设备的MPCP钟表值,该报文的驻留时间等于出口时戳减去入口时戳,并把驻留时间填到相应的报文correct1nField域中。 When [0011] Advantageously, the difference in the packet processing module is arranged to calculate the dwell time synchronization packets into the packets to the OLT physical port, a port in the PCS layer or the MAC layer of the recording apparatus OLT timepiece MPCP value, i.e. the inlet stamp, and the value of the watch comes to the tail of the packet; when forwards the packets to the ONU, extracting timestamp inlet end of packet, and forwards the packets to and from the ONU clock when the device is physically connected to the port, the MPCP port clocks values ​​PCS layer or the MAC layer of the recording ONU apparatus, the residence time of the packet timestamp minus the timestamp entry is equal to the outlet, and the residence time to fill the respective packets Wen correct1nField domain.

[0012]作为优选,所述报文时差处理模块进一步被设置为,当工作在P2P TC时,从时钟设备和ONU设备物理口、主时钟设备和OLT设备物理口之间的P2P测距按照1588v2的协议来实现。 [0012] Advantageously, the difference in the packet processing module is further arranged to, when operating in P2P the TC, the distance between a clock from the P2P devices and the ONU physical port, the master clock device and the OLT according to a physical port 1588v2 the protocol is implemented.

[0013]作为优选,所述OLT设备和ONU设备内部涉及到的时戳计数器,采用各自的32位二进制MPCP时戳计数器。 [0013] Advantageously, when the internal device OLT and ONU counters apparatus related to the stamp, each timestamp counter using 32-bit binary MPCP.

[00M] 作为优选,所述ONU设备上采用独立的32位二进制freerun计数器。 [00M] Advantageously, the ONU independent 32-bit binary counter freerun device.

[0015] 本发明所述的实现通信网络透明时钟传递的方法及系统,利用EPON系统本身已经同步了的MPCP计数器作为计算1588同步报文驻留时间的参考时钟,将OLT设备和ONU设备虚拟化为一个设备,OLT设备和ONU设备之间的光纤连接(通过分光器)看成了设备本身的一部分,简化了TC钟驻留时间的处理过程,去除ONU设备和OLT设备间的P2P测距过程,从ONU设备、OLT设备二步修正改为一步修正,降低设计复杂度,增加系统可靠性;此外,在同步报文尾部添加时戳字段,使同步报文入口时戳能携带到设备出口(即OLT-ONU之间)。 [0015] Method and system for communication network transparent transmission clock according to the present invention, the system itself using EPON MPCP counter has been synchronized to the reference clock 1588 as calculated dwell time of the packet, the ONU and the OLT device virtualization a fiber optic connection between devices, the OLT and the ONU see become a part of the device itself (through the beam splitter), simplifying the process residence time TC clock, removing P2P ranging procedure between the OLT and the ONU from the ONU, the OLT device two-step correction to the correction step, to reduce design complexity, increased system reliability; Furthermore, stamp field in the synchronous packet tail adding the timestamp synchronization packet to a device capable of carrying the inlet port ( i.e., between the OLT-ONU).

[0016]以下结合附图及具体实施例对本发明做进一步详细描述。 [0016] accompanying drawings and the following specific embodiments of the present invention will be further described in detail.

附图说明 BRIEF DESCRIPTION

[0017] 图1为现有技术1588 TC时钟传递示意图; [0017] FIG. 1 is a schematic view of the prior art transmission 1588 TC clock;

图2为本实施例的1588 TC时钟传递示意图; 1588 TC clock Example 2 of the present embodiment schematic view of the transmission;

图3为本实施例的SYNC报文驻留时间处理不意图; SYNC packets embodiment 3 of the present embodiment is not intended to deal with a dwell time;

图4为本实施例的SYNC报文添加尾部字段示意图; FIG SYNC packet 4 is a schematic view of an embodiment of adding tail field;

图5为本实施例实现通信网络透明时钟传递的系统框图。 5 a system block diagram of a communication network to achieve transparent transfer clock of the present embodiment.

具体实施方式 Detailed ways

[0018] —种实现通信网络透明时钟传递的方法,包括如下步骤: [0018] - Method of implementations of a communication network transparent transfer clock, comprising the steps of:

步骤I)、ΕΡ0Ν网络天然是一个同步系统,它不仅实现了频率同步,还实现了时间的同步。 Step I), ΕΡ0Ν natural network is a synchronous system, it is not only to achieve frequency synchronization, time synchronization is also achieved. OLT设备本地维护一个32位的二进制计数器,称为OLT的MPCP钟表。 OLT device maintains a local 32-bit binary counter, called the OLT MPCP timepiece. 每一个ONU设备也要维护一个32位的二进制计数器,称为ONU的MPCP钟表。 Each ONU device also maintains a 32-bit binary counter, called the ONU MPCP clock. ONU的MPCP钟表是通过OLT设备发送的MPCP报文来进行时间同步的。 The timepiece ONU MPCP time synchronization is performed by the OLT MPCP message sent. 由于ONU设备实现了对OLT设备的频率同步,ONU的MPCP钟表在OLT设备发送MPCP同步报文间隙内,ONU的MPCP钟表与OLT的MPCP钟表走过的时间基本一致。 Since the ONU OLT realizes the frequency synchronization apparatus, the ONU in the OLT MPCP timepiece device transmits the synchronization MPCP message gap, the ONU and the OLT MPCP MPCP timepiece timepiece through consistent time. 另外,OLT设备为了控制每一个ONU设备的上行时间窗口,使用MPCP协议报文实现测距的功能,获得OLT设备与每一个ONU设备之间的光纤延时(round trip time,RTT),也就是ONU钟表和OLT钟表之间的固定偏差RTT/2。 Further, the OLT to control the ONU upstream time window for each device, using MPCP ranging packets to implement the function, to obtain fiber delay (round trip time, RTT) between OLT and each ONU with device, i.e. droop RTT between OLT and ONU timepiece watch / 2. 修正后的ONU的MPCP钟表与OLT的MPCP钟表完全同步,误差控制在几十纳秒以内。 The ONU MPCP corrected timepiece of the OLT MPCP fully synchronized clocks, errors are less than several tens of nanoseconds. 本发明正是利用了EPON系统的时间同步特性,将OLT设备和ONU设备虚拟为一台同步系统设备,简化系统传递透明时钟过程,如图2所示; The present invention is the use of time synchronization characteristics EPON system, the virtual ONU and the OLT device is a synchronous system equipment, simplifying the system clock transparent transfer process, shown in Figure 2;

步骤2)、在同步报文尾部添加时戳字段,使同步报文入口时戳能携带到设备出口(0LT-ONU之间);具体过程为:1588对时过程中,主时钟设备与从时钟设备之间交互的报文主要有ANNOUNCE、SYNC、FOLLOffUP、DELAY_REQ、DELAY_RESP。 Step 2), the time stamp adding synchronization packet trailer field so that stamp can carry the device to the outlet (between 0LT-ONU) synchronization packet entry; specific process: when process 1588 pairs, the master clock device and the slave clock packets exchanged between equipment are ANNOUNCE, SYNC, FOLLOffUP, DELAY_REQ, DELAY_RESP. 其中SYNC、DELAY_REQ 报文通过上述网络设备时,需要计算报文驻留时间,并把驻留时间补偿到SYNC (one-step)或者F0LL0WUP(two-step)报文的correct1nField域中,DELAY_REQ (one-step)或者对应DELAY_RESP(two-step)报文的correct1nField域中,如图3所示。 Wherein when SYNC, DELAY_REQ apparatus via the network packets, the packets need to calculate the dwell time, the dwell time compensation and the SYNC (one-step) or F0LL0WUP (two-step) packets correct1nField domain, DELAY_REQ (one -step) or a corresponding DELAY_RESP (two-step) packets correct1nField domain, as shown in FIG. SYNC报文进入OLT设备的物理端口时,在端口的PCS层或者MAC层记录下OLT设备的MPCP钟表值(入口时戳),并把钟表值附带到SYNC报文的尾部,如图4。 When SYNC packets into the physical port of the OLT device, (inlet timestamp) Watch the MPCP in the OLT value PCS layer or the MAC layer, a recording port, and the value comes to watch the tail SYNC packet, as shown in FIG 4. 当SYNC报文转发到ONU设备后,提取报文尾部的入□时戳,并在SYNC报文转发到ONU设备的与从时钟设备相连的物理口时,在端口PCS层或者MAC层记录下ONU设备的MPCP钟表值(出口时戳,修正RTT/2)。 When SYNC packets are forwarded to the ONU, extracted time stamp into the □ packet tail, and forwarded to the SYNC message ONU device when clock device physical port connected from the port PCS layer or the MAC layer of the recording ONU MPCP timepiece device value (time stamp outlet, corrected RTT / 2). SYNC报文的驻留时间等于出口时戳减去入口时戳(二进制无符号减法),并把驻留时间填到相应的报文correct1nField域中AELAY+REQ报文的驻留时间处理方式与SYNC报文的基本一致; Subtracting the time stamp entry timestamp is equal to the residence time of the outlet SYNC packet (binary unsigned subtraction), and the residence time to fill the respective AELAY + REQ message dwell time domain approach to the SYNC message correct1nField messages are basically the same;

步骤3)、根据同步系统设备得到的修正驻留时间、主时钟设备和OLT设备物理口之间的P2P测距、以及从时钟设备与ONU设备物理口之间的P2P测距,得到同步报文从主时钟设备传递到从时钟设备的时间差。 Step 3), the residence time synchronization system according to the modified device obtained, P2P device ranging between the master clock and the OLT physical interface, as well as from the P2P clock device and the distance between the ONU physical port, synchronized packet transmitted from the main device to the clock from the clock device time difference.

[0019] 当工作在P2P TC时,从时钟设备和ONU设备物理口、主时钟设备和OLT设备物理口之间的P2P测距按照1588v2的协议来实现。 [0019] When operating in P2P TC, the slave clock device and the ONU physical port, P2P device ranging between the master clock and the OLT according to the protocol physical port 1588v2 be implemented.

[0020] 上述方法的实现可基于一种实现通信网络透明时钟传递的系统,如图5所示,包括: [0020] The foregoing method may be a communication network based on a system clock transmission transparent implementation, shown in Figure 5, comprising:

报文时戳处理模块101:在同步报文尾部添加时戳字段,使同步报文入口时戳携带到设备出口; Packet time stamp processing module 101: timestamp field in the synchronous packet tail addition the timestamp synchronization packets carried to the inlet device outlet;

报文时差处理模块102:根据同步系统设备得到的修正驻留时间、主时钟设备和OLT设备物理口之间的P2P测距、以及从时钟设备与ONU设备物理口之间的P2P测距,计算同步报文从主时钟设备传递到从时钟设备的时间差。 Time difference message processing module 102: The P2P residence time ranging between corrected synchronization system devices obtained, the master clock device and the OLT physical interface, and P2P device and the distance between the clock from the ONU physical port, calculated synchronization message transmitted from the main device to the clock from the time difference between the clock device.

[0021] 所述报文时差处理模块102在实现过程中具体被设置为,计算报文驻留时间的同步报文进入OLT设备的物理端口时,在端口的PCS层或者MAC层记录下OLT设备的MPCP钟表值,即入口时戳,并把钟表值附带到该报文的尾部;当该报文转发到ONU设备后,提取报文尾部的入口时戳,并在该报文转发到ONU设备与从时钟设备相连的物理口时,在端口PCS层或者MAC层记录下ONU设备的MPCP钟表值,该报文的驻留时间等于出口时戳减去入口时戳,并把驻留时间填到相应的报文correct1nField域中。 When [0021] the difference in the packet processing module 102 is specifically arranged to calculate the dwell time of the synchronization message packets physical port of the OLT device in the implementation, the ports in the PCS layer or the MAC layer of the recording apparatus OLT the timepiece MPCP value, i.e., the inlet stamp, and the value of the watch comes to the tail of the packet; when forwards the packets to the ONU, extracting the inlet end of packet time stamp, and forward the message to the ONU subtracting the time stamp with the inlet port when the device is physically connected to the clock from the port in the PCS layer or MAC layer MPCP timepiece value recorded ONU apparatus, the residence time stamp packet is equal to the outlet, and the residence time to fill the telegram correct1nField domain.

[0022] 所述OLT设备和ONU设备内部涉及到的时戳计数器,采用各自的32位二进制MPCP时戳计数器。 [0022] The OLT and the ONU when the intra-equipment related to the time stamp counter, the respective timestamp counter using 32-bit binary MPCP. 所述ONU设备上采用独立的32位二进制freerun计数器,这样ONU MPCP计数器的几十纳秒误差不会引入到ONU设备的P2P测距中。 The independent 32-bit binary counter freerun on the ONU, the MPCP counter of the ONU so that the error will not be introduced into the tens of nanoseconds P2P ranged ONU apparatus.

[0023] 本实施例所述的实现通信网络透明时钟传递的方法及方法,利用EPON系统本身已经同步了的MPCP计数器作为计算1588同步报文驻留时间的参考时钟,将OLT设备和ONU设备虚拟化为一个设备,OLT设备和ONU设备之间的光纤连接(通过分光器)看成了设备本身的一部分,简化了TC钟驻留时间的处理过程,去除ONU设备和OLT设备间的P2P测距过程,从ONU设备、OLT设备二步修正改为一步修正,降低设计复杂度,增加系统可靠性;此外,在同步报文尾部添加时戳字段,使同步报文入口时戳能携带到设备出口(即OLT-ONU之间)。 [0023] The present method and a communication network implemented method described in the embodiment of the transparent clock transmitted by the system itself EPON MPCP counter has been synchronized to the reference clock 1588 as calculated dwell time of the packet, the OLT device and the ONU Virtual into a device, the fiber optic connection between the OLT and the ONU see become a part of the device itself (through the beam splitter), simplifying the process residence time TC clock, removing P2P ranging between the OLT and the ONU process, from the ONU, the OLT device two-step correction to the correction step, to reduce design complexity, increased system reliability; Furthermore, stamp field in the synchronous packet with the tail portion, so that the synchronization timestamp packets can carry the inlet to the outlet device (i.e., between the OLT-ONU).

[0024]上述实施例和图式并非限定本发明的产品形态和式样,任何所属技术领域的普通技术人员对其所做的适当变化或修饰,皆应视为不脱离本发明的专利范畴。 [0024] The foregoing embodiments and drawings are not defined style and product forms of the present invention, any person of ordinary skill in the art or modifications thereof suitable changes made, it should be considered are possible without departing from the scope of the invention.

Claims (10)

1.一种实现通信网络透明时钟传递的方法,其特征在于包括如下步骤: 步骤I)、利用EPON系统的时间同步特性,将OLT设备和ONU设备虚拟为一台同步系统设备; 步骤2)、在同步报文尾部添加时戳字段,使同步报文入口时戳携带到设备出口; 步骤3)、根据同步系统设备得到的修正驻留时间、主时钟设备和OLT设备物理口之间的P2P测距、以及从时钟设备与ONU设备物理口之间的P2P测距,得到同步报文从主时钟设备传递到从时钟设备的时间差。 1. A method for a communication network to achieve transparent transfer clock, comprising the steps of: the I step), using the time synchronization characteristics EPON system, the virtual ONU and the OLT device is a synchronous system equipment units; Step 2), timestamp field in the synchronous packet tail adding the stamp carrying device to the outlet when the inlet synchronization packet; step 3), P2P measured in accordance with the correction between the residence time synchronization system devices obtained, the master clock device and the OLT physical port distance, and a distance between a clock from the P2P device and the ONU physical port, synchronized packet transmitted from the main device to the clock from the time difference between the clock device.
2.如权利要求1所述的一种实现通信网络透明时钟传递的方法,其特征在于:所述步骤2)具体过程为:需要计算报文驻留时间的同步报文进入OLT设备的物理端口时,在端口的PCS层或者MAC层记录下OLT设备的MPCP钟表值,即入口时戳,并把钟表值附带到该报文的尾部;当该报文转发到ONU设备后,提取报文尾部的入口时戳,并在该报文转发到ONU设备与从时钟设备相连的物理口时,在端口PCS层或者MAC层记录下ONU设备的MPCP钟表值,该报文的驻留时间等于出口时戳减去入口时戳,,并把驻留时间填到相应的报文correct1nField域中。 2. An A method according to claim 1 communications network to achieve transparent transfer clock, wherein: said step 2) specific process: the need to calculate the sync message packet residence time physical port of the OLT device when, at the value of the MPCP timepiece PCS layer or the MAC layer of the recording port of the OLT device, i.e. the inlet stamp, and the value of the watch comes to the tail of the packet; when forwards the packets to the ONU, extracting packet tail the timestamp entry and forwards the packets to the ONU and the ONU MPCP timepiece value when the clock device connected to the physical port from the port in the PCS layer or the MAC layer of the recording, the residence time is equal to the outlet when the packet stamp and time stamp subtracted ,, inlet to the fill dwell time of the respective packet correct1nField domain.
3.如权利要求1所述的一种实现通信网络透明时钟传递的方法,其特征在于:当工作在P2P TC时,从时钟设备和ONU设备物理口、主时钟设备和OLT设备物理口之间的P2P测距按照1588v2的协议来实现。 One of the claim 1 method in a communication network to achieve transparent transfer clock, wherein: when a P2P TC, the slave clock device and the ONU physical port, the master clock device and the physical interface between the OLT work the P2P ranging 1588v2 according to protocol.
4.如权利要求1所述的一种实现通信网络透明时钟传递的方法,其特征在于:所述OLT设备和ONU设备内部涉及到的时戳计数器,采用各自的32位二进制MPCP时戳计数器。 4. An method according to claim 1 clock transmitted a communication network transparent implementation, wherein: said inner OLT and the ONU apparatus related to the timestamp counter, using the timestamp counter 32 respective binary MPCP.
5.如权利要求1所述的一种实现通信网络透明时钟传递的方法,其特征在于:所述ONU设备上采用独立的32位二进制freerun计数器。 One of the 5. The method of claim 1, a communications network to achieve transparent transfer clock, wherein: the ONU independent 32-bit binary counter freerun device.
6.—种实现通信网络透明时钟传递的系统,其特征在于包括: 报文时戳处理模块:在同步报文尾部添加时戳字段,使同步报文入口时戳携带到设备出口; 报文时差处理模块:根据同步系统设备得到的修正驻留时间、主时钟设备和OLT设备物理口之间的P2P测距、以及从时钟设备与ONU设备物理口之间的P2P测距,计算同步报文从主时钟设备传递到从时钟设备的时间差。 6.- such systems enable communication network transparent transfer clock, comprising: a processing module packet time stamp: stamp field in the synchronous packet tail added the stamp carrying device to the outlet when the inlet synchronization packet; packet difference the processing module: the distance between the P2P corrected dwell time synchronization system devices obtained, the master clock device and the OLT physical interface, as well as from the P2P clock device and the distance between the ONU physical port, synchronization packets calculated the difference between the master clock device to the slave clock device.
7.如权利要求1所述的一种实现通信网络透明时钟传递的系统,其特征在于:报文时差处理模块被设置为,计算报文驻留时间的同步报文进入OLT设备的物理端口时,在端口的PCS层或者MAC层记录下OLT设备的MPCP钟表值,即入口时戳,并把钟表值附带到该报文的尾部;当该报文转发到ONU设备后,提取报文尾部的入口时戳,并在该报文转发到ONU设备与从时钟设备相连的物理口时,在端口PCS层或者MAC层记录下ONU设备的MPCP钟表值,该报文的驻留时间等于出口时戳减去入口时戳,并把驻留时间填到相应的报文correct1nField域中。 Packet time difference processing module is arranged to calculate the dwell time of the packets into the packet synchronization apparatus OLT physical port: 7. claim 1, one of the communication network system for implementing transparent transmission clock, wherein in the PCS layer or MPCP port value timepiece an OLT MAC layer of the recording apparatus, i.e., the inlet stamp, and the value of the watch comes to the tail of the packet; when forwards the packets to the ONU, extracting packet tail the inlet stamp and forwards the packets to the ONU and the ONU MPCP timepiece value when the clock device connected to the physical port from the port in the PCS layer or the MAC layer of the recording, the residence time stamp packet is equal to the outlet subtracting inlet stamp, and the residence time to fill the respective packets correct1nField domain.
8.如权利要求6所述的一种实现通信网络透明时钟传递的系统,其特征在于:报文时差处理模块进一步被设置为,当工作在P2P TC时,从时钟设备和ONU设备物理口、主时钟设备和OLT设备物理口之间的P2P测距按照1588v2的协议来实现。 8. An implement according to claim 6, wherein the communication network system clock transparent transmission, wherein: the time difference message processing module is further arranged to, when operating in P2P TC, the slave clock device and the ONU physical port, P2P device ranging between the master clock and the OLT according to a physical port of 1588v2 protocol.
9.如权利要求6所述的一种实现通信网络透明时钟传递的系统,其特征在于:所述OLT设备和ONU设备内部涉及到的时戳计数器,采用各自的32位二进制MPCP时戳计数器。 9. An implement according to claim 6, wherein the communication network system clock transparent transmission, wherein: said inner OLT and the ONU apparatus related to the timestamp counter, using the timestamp counter 32 respective binary MPCP.
10.如权利要求6所述的一种实现通信网络透明时钟传递的系统,其特征在于:所述ONU设备上采用独立的32位二进制freerun计数器。 10. An implement according to claim 6, wherein the communication network system clock transparent transmission, wherein: the ONU independent 32-bit binary counter freerun device.
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