Clock synchronization method and device for EPON (Ethernet Passive Optical Network) system
A clock synchronization and system clock technology, applied in time division multiplexing systems, electrical components, multiplexing communications, etc., to simplify the design of synchronous clocks, reduce costs, and enrich types
Inactive Publication Date: 2016-06-01
FENGHUO COMM SCI & TECH CO LTD
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Problems solved by technology
[0005] The technical problem to be solved by the present invention is how to solve the problem of how to use the synchronous Ethernet to simplify the local PON system clock design of the EPON system
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[0024] The invention provides a clock synchronization method of an EPON system, which enriches the types of OLT synchronization clock sources and simplifies the design of the synchronization clock at the OLT end. The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.
[0025] Ethernet is currently the most widely used network technology in the world, and it tends to gradually replace PDH and SONET / SDH transmission networks. For the high-precision clock synchronization requirements of Ethernet, the latest standard solution is Synchronous Ethernet (SvncE). In SyncE, Ethernet synchronizes its bit clock with a high-quality, traceable primary reference clock signal in the same manner as SONET (Synchronous Optical Network) / SDH (Synchronous Digital Hierarchy). Now the latest version is IEEE1588, namely IEEE1588v2. This standard defines a clock synchronization protocol in measurement and automation systems, esp...
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The invention discloses a clock synchronization method and device for an EPON (Ethernet Passive Optical Network) system. The method comprises the following steps: extracting a synchronous Ethernet clock from a gigabit Ethernet optical interface at an OLT (Optical Line Terminal) side; converting the frequency of the synchronous Ethernet clock to obtain a low-speed differential clock meeting the transmission requirement of an OLT backboard; extracting, by each service disk, the low-speed differential clock from the backboard, and performing frequency multiplication to form a PON (Passive Optical Network) system clock used by a PON chip on each service disk; transmitting the PON system clock to an ONU (Optical Network Unit) via an optical path; and extracting, by the PON chip on the ONU, the PON system clock used by a TDM (Time Division Multiplexing) service disk of the ONU side. According to the method and the device, the synchronous Ethernet clock extracted from the synchronous Ethernet (SvncE) is used as a synchronous clock source of the OLT side, so that the input of a specific external hardware clock source is not needed, the category of the OLT synchronous clock source is enriched, the synchronous clock design of the OLT side is simplified, and the cost is lowered.
Description
technical field [0001] The invention relates to clock synchronization of an EPON system, in particular to a clock synchronization method and device of an EPON system. Background technique [0002] Clock synchronization is the prerequisite for the normal operation of the network system. To synchronize the entire system, there must be a common reference clock. In EPON, the PON system clock at the central office is used as the reference clock, and each ONU clock is synchronized with the PON system clock. [0003] In the current EPON system, the central PON system clock is input by an external clock source, such as 1PPS+TOD or IEEE1588V2, and these external clocks are all generated by special hardware devices. [0004] In view of the fact that Synchronous Ethernet (SvncE) has been widely used, and the International Telecommunication Union released the IEEE1588 standard related to the Precision Time Synchronization Protocol (PTP) in its G.8261, how to use Synchronous Ethernet to...
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Login to View More IPC IPC(8): H04J3/06
CPCH04J3/0638
Inventor 张前进
Owner FENGHUO COMM SCI & TECH CO LTD