CN108668182B - Synchronous testing method for optical transmission system - Google Patents
Synchronous testing method for optical transmission system Download PDFInfo
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- CN108668182B CN108668182B CN201710188616.XA CN201710188616A CN108668182B CN 108668182 B CN108668182 B CN 108668182B CN 201710188616 A CN201710188616 A CN 201710188616A CN 108668182 B CN108668182 B CN 108668182B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0062—Network aspects
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
- H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
- H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
- H04B10/0793—Network aspects, e.g. central monitoring of transmission parameters
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0062—Network aspects
- H04Q2011/0079—Operation or maintenance aspects
- H04Q2011/0083—Testing; Monitoring
Abstract
The application discloses a synchronous testing method of an optical transmission system, which solves the problems of different-place synchronous reference measurement errors, limited testing conditions and the like. The method comprises the following steps: starting a clock test instrument to output a clock signal, and inputting the clock signal to an external synchronous input interface of a local network element; setting the local network element, outputting an external synchronous input interface signal through an output interface of a synchronous equipment timing generator, using the external synchronous input interface signal as a line clock, and transmitting the line clock to the line network element; setting each line network element, outputting a line signal input interface signal of each line network element through an output interface of a timing generator of the synchronization equipment, using the line signal input interface signal as a line clock, and transmitting the line clock to a local network element or a next line network element; and setting the local network element to enable a line signal input interface signal of the local network element to be output through an external synchronous output interface to serve as a tested signal and be accessed to the clock test instrument. The application also provides a corresponding test system. The invention improves the system test accuracy and gets rid of the limitation of a test source and a test reference point.
Description
Technical Field
The present application relates to the field of communications technologies, and in particular, to a synchronous testing method for an optical transmission system.
Background
The synchronous network is closely connected with the transmission network as an important support network, and the traditional SDH/MSTP optical transmission network works in a TDM mode and can stably run only by a clock synchronous signal with high reliability and high performance. Although the requirement of the OTN/PTN technology for synchronization is different from that of the conventional SDH/MSTP, as an important bearer network, it needs to perform synchronization signal interfacing with other bearer networks, and on the other hand, it needs to provide support for timing link organization of the synchronization network, and also faces the problem of carrying frequency and time synchronization signals.
The existing SDH/MSTP, PTN and OTN optical transmission system frequency synchronization network test plays an important role in performance verification, engineering opening and maintenance, however, the existing network test method has two disadvantages: on one hand, the source end and the sink end are in different machine rooms, and different synchronous reference sources need to be connected, so that measurement errors are inevitably introduced to a certain degree; on the other hand, the test source and the test reference are limited by the physical location of the machine room, the atomic clock carrying condition for testing, the synchronous signal leading condition of the optical transmission equipment, and the like, and the existing network test can only select a specific site for testing and often cannot cover the typical synchronous link of the optical transmission system.
Disclosure of Invention
The application provides a synchronous testing method and a synchronous testing system for an optical transmission system, and solves the problems of different-place synchronous reference measurement errors, limited testing conditions and the like.
The embodiment of the application provides a synchronous testing method for an optical transmission system, wherein the optical transmission system comprises a local network element and at least one line network element, the local network element and the line network element both comprise a line signal input interface, an external synchronous output interface and a synchronous equipment timing generator output interface, and the method comprises the following steps:
starting a clock test instrument to output a clock signal, and inputting the clock signal to an external synchronous input interface of the local network element;
setting the local network element, outputting an external synchronous input interface signal through an output interface of a synchronous equipment timing generator, using the external synchronous input interface signal as a line clock, and transmitting the line clock to the line network element;
setting each line network element, outputting a line signal input interface signal of each line network element through an output interface of a timing generator of the synchronization equipment, using the line signal input interface signal as a line clock, and transmitting the line clock to a local network element or a next line network element;
and setting the local network element to enable a line signal input interface signal of the local network element to be output through an external synchronous output interface to serve as a tested signal and be accessed to the clock test instrument.
In the synchronous testing method of the optical transmission system, the optical transmission system is an SDH/MSTP, PTN or OTN system.
Preferably, the clock signal is 2Mbps or 2 MHz.
Preferably, in the synchronous testing method of the optical transmission system, any one node in the optical transmission system is selected to be used as a local network element; selecting at least one other node in the optical transmission system to be used as a line network element; and the local network element and the line network element are sequentially connected through a transmission channel and realize loopback.
The embodiment of the present application further provides a synchronous testing system for an optical transmission system, where the optical transmission system includes a local network element and at least one line network element, where the local network element and the line network element both include a line signal input interface, an external synchronous output interface, and a synchronous device timing generator output interface, and the testing system includes a clock testing instrument: the clock test instrument outputs 2Mbps or 2MHz clock signals and inputs the clock signals to an external synchronous input interface of the local network element;
the external synchronous input interface signal of the local network element is output through the output interface of the synchronous device timing generator, used as a line clock and transmitted to the line network element;
the line signal input interface signal of the line network element is output through the output interface of the timing generator of the synchronous equipment, used as a line clock and transmitted to a local network element or a next line network element;
and the line signal input interface signal of the local network element is output through the external synchronous output interface, is used as a tested signal and is accessed into the clock test instrument.
In the synchronous test system of the optical transmission system, the optical transmission system is an SDH/MSTP, PTN or OTN system.
Preferably, the clock signal is 2Mbps or 2 MHz.
Preferably, in the synchronous test system of the optical transmission system, the local network element is any node in the optical transmission system; the line network element comprises at least one other node in the optical transmission system; and the local network element and the line network element are sequentially connected through a transmission channel and realize loopback.
The embodiment of the application adopts at least one technical scheme which can achieve the following beneficial effects: in summary, the present invention provides a novel synchronous loopback test method for synchronous signal transmission based on network synchronization in SDH/MSTP, PTN, OTN optical transmission systems, which solves the problem of measurement error caused by a remote test reference and improves the system test accuracy; on the other hand, the method gets rid of the limitation of a test source and a test reference point, and can test at any node of the optical transmission system according to actual needs, thereby reducing the test cost and reducing the operation and maintenance risks.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
FIG. 1 is a functional model of a frequency-synchronized clock of an optical transmission apparatus;
FIG. 2 is a diagram illustrating a conventional testing method for current network synchronization of an optical transmission system;
FIG. 3 is a diagram of a synchronous testing system of the optical transmission system according to the present invention;
fig. 4 is a flowchart of a synchronous testing method of an optical transmission system according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail and completely with reference to the following specific embodiments of the present application and the accompanying drawings. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The key point of the invention lies in that the clock loopback measurement is realized on the optical transmission equipment through the clock selector directional derivation function T4-T1/TE/TN. The technology is suitable for OTN/POTN, PTN or SDH/MSTP equipment in the ring network topology environment.
The invention carries out local loopback test on the synchronous signal through the directional derivation function of the optical transmission equipment clock, thereby eliminating the measurement error introduced by different sources of the clock reference at different places on one hand, getting rid of the bottleneck of limited environment of deploying the clock reference at the test site on the other hand, and providing a flexible solution for the optical transmission system to carry out the current network test of the synchronous signal.
The following abbreviations are used in this application: LPR-area reference clock source; OTN — optical transport network; POTN-packet-transport optical network; PTN-packet transport network; PRC — master reference clock; SDH — synchronous digital hierarchy; MSTP — multi-service transport platform; NE-network element.
The technical solutions provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings.
Fig. 1 is a functional model of a frequency-synchronous clock of an optical transmission apparatus. In the existing clock model of optical transmission equipment, TN/TE/T1 are OTUk/synchronous ethernet/STM-N input interfaces, T2 is a tributary signal input interface, T3 is an external synchronous input interface, SETG is a synchronous equipment timing generator, T4 is an external synchronous output interface, and T0 is an internal timing interface, respectively. The OTN/POTN equipment supports TN/TE/T1/T2/T3 input clock interfaces; the PTN equipment supports a TE/T1/T2/T3 input clock interface; the SDH/MSTP equipment supports T1/T2/T3 input clock interface.
Fig. 2 is a schematic diagram of a conventional testing method for current network synchronization of an optical transmission system. In a conventional optical transmission system, when a network synchronization mode is adopted for carrying out a synchronization signal transmission test, a source end and a sink end are remote nodes. A clock synchronization device (PRC or LPR) tracing to a satellite is usually deployed at a source end, a 2M frequency signal is input to a clock interface board of an optical transmission device, the clock interface board sends a synchronization signal to a system clock module through a back board or a jumper, after multi-station point-by-point processing, a 2M synchronization test signal is output on the clock interface board of a sink end, and a synchronization test is performed on a synchronization test instrument tracing to a cesium atomic clock in an access station.
The prior testing technology has the following two disadvantages:
on one hand, different sources of different-place reference introduce measurement errors and cannot be corrected. Although the synchronous reference of the source end and the test reference of the sink end both reach the frequency accuracy level of the first-level reference clock 3E-12 in China, because the synchronous reference of the source end and the test reference of the sink end are in a machine room at a different place, measurement errors caused by non-ideal factors such as satellite receiving quantity, satellite receiving position, satellite receiver processing performance, instrument internal frequency division processing, phase-locked loop processing and the like are difficult to avoid, and the part of errors cannot be corrected and compensated through a model, so that the test precision of a synchronous system test is influenced.
On the other hand, the test environment and the test site are limited by a plurality of factors, which affects the selection of the test site and the selection of the typical synchronous link. For frequency synchronization test, a host computer room needs to deploy a PRC or LPR primary reference clock device to provide a test reference, or needs an additional cesium atomic clock to output a reference signal before frequency synchronization system test can be performed. Therefore, the testing method has higher requirements on the field conditions of the machine room, and particularly has the objective problem of difficult site selection on a typical synchronous link needing to be tested.
Fig. 3 is a structural diagram of a synchronous testing system of an optical transmission system according to the present invention. The optical transmission system is an SDH/MSTP, PTN or OTN system. The embodiment of the application provides a synchronous test system of an optical transmission system, the optical transmission system comprises a local network element NE1 and at least one line network element NE 2-NEn, the local network element and the line network element both comprise a line signal input interface TN/TE/T1, an external synchronous input interface T3, an external synchronous output interface T4 and a synchronous equipment timing generator output interface T0, and the test system comprises a clock test instrument; the clock test instrument outputs 2Mbps or 2MHz clock signals and inputs the clock signals to an external synchronous input interface of the local network element; the external synchronous input interface signal of the local network element is output through the output interface of the synchronous device timing generator, used as a line clock and transmitted to the line network element; the line signal input interface signal of the line network element is output through the output interface of the timing generator of the synchronous equipment, used as a line clock and transmitted to a local network element or a next line network element; and the line signal input interface signal of the local network element is output through the external synchronous output interface, is used as a tested signal and is accessed into the clock test instrument.
Preferably, in the synchronous test system of the optical transmission system, the local network element is any node in the optical transmission system; the line network element comprises at least one other node in the optical transmission system; and the local network element and the line network element are sequentially connected through a transmission channel and realize loopback.
For example, in FIG. 1, clock signal injection (r): the clock test instrument is used as a frequency synchronization source, a clock signal is injected into a local network element NE1 in a 2Mbps or 2MHz mode, and a line clock signal is output to NE2 after a clock selector unit of NE1 sets T0 to T3;
clock signal transmission 2: the clock selectors of the NE 2-NEn network elements are configured as T0 ═ T1/TE/TN, that is, the clock is extracted from the line, and after the clock is serially connected to the local system clock, the clock signal is forwarded to the next network element through the line;
leading the clock signal to connect to the third step: the line clock signal of NEn is sent back to the local network element NE1, and after T4 ═ T1/TE/TN is configured in the clock selector, the external clock output signal of NE1 is connected to the meter for testing.
Fig. 4 is a flowchart of a synchronous testing method of an optical transmission system according to the present invention. In the synchronous testing method of the optical transmission system, the optical transmission system is an SDH/MSTP, PTN or OTN system. The optical transmission system comprises a local network element NE1 and at least one line network element NE 2-NEn, wherein the local network element and the line network element both comprise a line signal input interface TN/TE/T1, an external synchronous input interface T3, an external synchronous output interface T4 and a synchronous equipment timing generator output interface T0, and the optical transmission system synchronization test method provided by the embodiment of the application comprises the following steps:
for example, a clock test instrument is started, and after confirming that a clock signal of 2Mbps or 2MHz is output normally, the clock signal is injected into the local network element NE 1;
for example, T0 ═ T3 is configured on the clock selector of the local network element NE1, and output to the line network element NE 2;
for example, T0 ═ T1/TE/TN is configured on a clock selector of the line network element NE2, and after extracting a clock from the line, a system clock is connected in series and output again with the line clock;
if there are multiple line network elements, e.g. NE 3-NEn, configuring according to step 13;
and step 14, setting the local network element to enable a line signal input interface signal of the local network element to be output through an external synchronous output interface to serve as a tested signal and be accessed to the clock test instrument.
For example, after T4 ═ T1/TE/TN is configured in the clock selector of the local network element NE1, the external synchronous output interface T4 signal is connected to the meter for testing.
Preferably, in the synchronous testing method of the optical transmission system, any one node in the optical transmission system is selected to be used as a local network element; selecting at least one other node in the optical transmission system to be used as a line network element; and the local network element and the line network element are sequentially connected through a transmission channel and realize loopback.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.
Claims (7)
1. A synchronous test method for optical transmission system, said optical transmission system includes a local network element and at least one line network element, said local network element and line network element include line signal input interface, external synchronous output interface, synchronous device timing generator output interface, characterized by that, it includes the following steps:
starting a clock test instrument to output a clock signal, and inputting the clock signal to an external synchronous input interface of the local network element;
setting the local network element, outputting an external synchronous input interface signal through an output interface of a synchronous equipment timing generator, using the external synchronous input interface signal as a line clock, and transmitting the line clock to the line network element;
setting each line network element, outputting a line signal input interface signal of each line network element through an output interface of a timing generator of the synchronization equipment, using the line signal input interface signal as a line clock, and transmitting the line clock to a local network element or a next line network element;
and setting the local network element to enable a line signal input interface signal of the local network element to be output through an external synchronous output interface to serve as a tested signal and be accessed to the clock test instrument.
2. The synchronous testing method of optical transmission system according to claim 1,
the optical transmission system is an SDH/MSTP, PTN or OTN system.
3. The synchronous testing method of optical transmission system according to claim 1,
selecting any node in the optical transmission system to be used as a local network element;
selecting at least one other node in the optical transmission system to be used as a line network element;
and the local network element and the line network element are sequentially connected through a transmission channel and realize loopback.
4. The synchronous testing method of optical transmission system according to any one of claims 1 to 3,
the clock signal is 2Mbps or 2 MHz.
5. A synchronous test system of an optical transmission system, the optical transmission system comprises a local network element and at least one line network element, the local network element and the line network element both comprise a line signal input interface, an external synchronous output interface and a synchronous device timing generator output interface, characterized in that,
the test system comprises a clock test instrument;
the clock test instrument outputs 2Mbps or 2MHz clock signals and inputs the clock signals to an external synchronous input interface of the local network element;
the external synchronous input interface signal of the local network element is output through the output interface of the synchronous device timing generator, used as a line clock and transmitted to the line network element;
the line signal input interface signal of the line network element is output through the output interface of the timing generator of the synchronous equipment, used as a line clock and transmitted to a local network element or a next line network element;
and the line signal input interface signal of the local network element is output through the external synchronous output interface, is used as a tested signal and is accessed into the clock test instrument.
6. The optical transmission system synchronization test system of claim 5,
the optical transmission system is an SDH/MSTP, PTN or OTN system.
7. The optical transmission system synchronization test system of claim 5,
the local network element is any node in the optical transmission system;
the line network element comprises at least one other node in the optical transmission system;
and the local network element and the line network element are sequentially connected through a transmission channel and realize loopback.
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| CN201710188616.XA CN108668182B (en) | 2017-03-27 | 2017-03-27 | Synchronous testing method for optical transmission system |
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| CN201710188616.XA CN108668182B (en) | 2017-03-27 | 2017-03-27 | Synchronous testing method for optical transmission system |
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| CN101286835B (en) * | 2007-04-11 | 2013-03-20 | 华为技术有限公司 | Clock tracing method, device and network element device |
| CN101431444B (en) * | 2007-11-07 | 2011-06-22 | 中兴通讯股份有限公司 | Test method for transmission equipment clock synchronous information switching time delay |
| CN106375054A (en) * | 2015-07-22 | 2017-02-01 | 中兴通讯股份有限公司 | OTN network element device, and OTN clock and time synchronization method and system |
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Effective date of registration: 20211227 Address after: 100191 No. 40, Haidian District, Beijing, Xueyuan Road Patentee after: CHINA ACADEMY OF INFORMATION AND COMMUNICATIONS Address before: 100191 No. 52 Garden North Road, Beijing, Haidian District Patentee before: CHINA ACADEME OF TELECOMMUNICATION RESEARCH OF MIIT |
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