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Synchronizing method in optical access network, optical switching device, center device, and remote device

A technology of central device and remote device, applied in the fields of synchronization, optical switch device, central device, remote device, optical access system, optical access network, program and recording medium, can solve the problem of lack of description

Inactive Publication Date: 2007-01-10
NEC COMM SYST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0028] In addition, Patent Document 1 does not describe the use of the optical switching medium OSM

Method used

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  • Synchronizing method in optical access network, optical switching device, center device, and remote device
  • Synchronizing method in optical access network, optical switching device, center device, and remote device
  • Synchronizing method in optical access network, optical switching device, center device, and remote device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0253] (method 1)

[0254]In Embodiment 1, the OLT also outputs the ranging of the OSM, and RTTs represents the round-trip delay time between the OLT and the OSM, TZ=RTTa-RTTs, wherein the round-trip time RTTa of the OLT and the ONU is obtained from the OLT, and the Tz is used to determine the uplink The connection startup time of the optical switching element.

[0255] figure 1 represents this example.

[0256] This embodiment is characterized in that the OLT performs ranging with respect to the OSM to measure the round-trip time RTTs, and the OLT performs ranging with respect to the ONU to measure the round-trip time RTTa of the control packet.

[0257] As shown in the figure, for the OSM to use the delay time Tz=RTTa-RTTs, the OLT informs the RTTa and RTTs or the RTTa-RTTs difference information, and the OLT sends the RTTa, RTTs information, or the difference RTTa-RTTs to the OSM. Once the OSM obtains Tz, the connection startup time t3* of the upstream optical switch el...

Embodiment 2

[0259] When the OLT performed the first ranging of the ONU, the REPORT message (uplink control packet) to the arrival time t3 of the GATE message was obtained at the output port of the upstream optical switch element of the optical switch module, Tz (=t3- t2) is obtained from the permitted activation time t2 written in the GATE message, using the Tz, the contact activation time of the upstream optical switching element is determined.

[0260] figure 2 Example 2 is shown.

[0261] In OSM, first, LLID, t1 and t2 are obtained using the GATE message used in the ONU direction. When the GATE message is received, the OSM clock is set to time t1.

[0262] First, the distance between the OSM and the ONU is arbitrary, and the time t2+Tx is set as the contact start time of the upstream switch element according to the clock of the OSM, and it detects the arrival of the REPORT message at the output port of the optical switch module, and the The contact duration is set to Tw, the rangin...

Embodiment 3

[0265] (method 3)

[0266] At the input port of the upstream optical switch element in the OSM, the upstream packet corresponding to the GATE message is detected at the LLID, using the upstream packet and the Tz to obtain Tz=t3*-t2 from the arrival time t3* , to determine the contact start time of the upstream optical switch element. However, t2 is the grant start time of the ONU written in the GATE message.

[0267] image 3 represents this example.

[0268] In this embodiment, the arrival time t3* of the uplink control packet can be detected at the input port of the uplink switch, the corresponding GATE message can be obtained from the LLID of the uplink packet, and the delay time Tz*= can be obtained from the time stamp of the GATE message The value of t3*-t2. After obtaining the Tz*, the arrival time t3* of the uplink control packet, that is, the contact activation time t3* of the uplink optical switch can be obtained by t3*=Tz*+t2.

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Abstract

The present invention provided synchronizing methods, optical switch modules, center devices, remote devices, optical access systems, optical access networks, programs, and recording media in the optical access network which can give the connection start time of the upstream optical switching element of the optical switch module. To the optical switch module, ranging functions are provided and the center device OLU carries out ranging of the optical switch module OSM as is the case of ranging of the remote device ONU. The center device OLU transmits the difference between roundtrip time of the remote device ONU and roundtrip time of optical switch module OSM, which is the result of these rangings, to the optical switch module OSM, and the optical switch module OSM can obtain the contact start time of the upstream optical switching element by calculating the contact start time using the difference.

Description

technical field [0001] The invention relates to a synchronization method in an optical access network, an optical switch device, a central device, a remote device, an optical access system, an optical access network, a program and a recording medium. Background technique [0002] Mentioned is a PON (Passive Optical Network) of an optical access network that does not utilize an OSM (Optical Switching Device) (for example, refer to Non-Patent Document 1). The PON has a passive element which is at least one optical splitter between a central (OLT) having a tree shape and a remote unit (ONU). The PON utilizes passive components, however the PON does not utilize optical switching devices. [0003] The technique described in Non-Patent Document 1 determines a relationship between time and cycle, that is, a synchronization method between two devices OLT and ONU constituting the PON. [0004] Described here is the relationship between the central unit (OLT) and the time associated...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B10/20H04B10/27H04B10/272H04B10/524H04J14/00H04J14/02H04L12/44
CPCH04L7/0075H04Q2011/0045H04Q2011/0064H04J3/0682H04Q11/0067
Inventor 野村拓望上田裕巳牧野州哲河西宏之坪井利宪黑川弘章小林纮一远藤弘之
Owner NEC COMM SYST
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