NETWORK SYSTEM, OPTICAL NETWORK UNIT AND OPTICAL LINE TERMINAL
First Claim
1. A network system comprising:
- a first OLT (Optical Line Terminal), a second OLT, a first ONU (Optical Network Unit), and a second ONU,wherein the first OLT and the second OLT are connected to the first ONU and the second ONU through an optical fiber shared by the first OLT and the second OLT such that data is transmitted between the first OLT and the first ONU and between the second OLT and the second ONU,the first OLT and the second OLT mutually share uplink communication band allocation information so that each of the first and second ONUs transmits an uplink frame, andthe first OLT allocates the uplink communication band to the first ONU by avoiding the uplink communication band that is allocated to the second ONU, and allocates the uplink communication band to the second ONU.
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Accused Products
Abstract
It is necessary to completely remove overlapping of signals between plural PONs in order to make the PONs coexist. Accordingly, it is required to share or intensively manage bandwidth use conditions over an optical fiber that serves as a common band between plural systems. Therefore, transmission clocks should be synchronized with high accuracy between plural systems. A reference clock is provided from an external device or a representative OLT to the entire systems to perform clock synchronization between plural systems, so that the overall systems are synchronized by synchronizing each OLT with the reference clock. A hierarchical management method is selected that manages ONUs under the control of each OLT by managing band use information arranged for each OLT with respect to an external device or a representative OLT for sharing of bandwidth use conditions between plural systems.
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Citations
22 Claims
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1. A network system comprising:
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a first OLT (Optical Line Terminal), a second OLT, a first ONU (Optical Network Unit), and a second ONU, wherein the first OLT and the second OLT are connected to the first ONU and the second ONU through an optical fiber shared by the first OLT and the second OLT such that data is transmitted between the first OLT and the first ONU and between the second OLT and the second ONU, the first OLT and the second OLT mutually share uplink communication band allocation information so that each of the first and second ONUs transmits an uplink frame, and the first OLT allocates the uplink communication band to the first ONU by avoiding the uplink communication band that is allocated to the second ONU, and allocates the uplink communication band to the second ONU. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A network system comprising:
a first OLT, a second OLT, a first ONU, and a second ONU, wherein the first ONU and the second ONU are connected to each other through an optical fiber shared by the first OLT and the second OLT to share a wavelength that transmits a downlink data between the first OLT and the first ONU and between the second OLT and the second ONU, the first OLT notifies the second OLT of a downlink frame transmission timing, and the second OLT transmits the downlink frame to the second ONU by avoiding a downlink frame transmission timing of the first OLT. - View Dependent Claims (15, 16)
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17. An ONU that is connected to an OLT and the other OLT of a system through an optical fiber shared by the OLT and the other OLT of the system, is further connected to the other ONU of the system, and transmits an uplink data based on an uplink band instruction from the OLT,
wherein the ONU performs a DBA control at DBA periods different from first OLT and the second OLT and shares a count start time and a count period that counts a reference timing performing the DBA control, and the ONU comprises an uplink frame counter that counts a relative time from the count start time and transmits an uplink frame based on the relative time from the count start time of the reference timing instructed from the uplink frame counter and the first OLT.
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18. An ONU that is connected to an OLT and the other OLT of a system through an optical fiber, is further connected to the other ONU of the system, and transmits an uplink frame based on an uplink band instruction from the OLT,
wherein the ONU performs a DBA control at different DBA periods different from the OLT and the other OLT of the system and shares a count start time and a count period that counts a reference timing performing the DBA control, the ONU comprises an uplink frame counter that counts the number of frames included during the count period and receives a frame identifier indicating whether an uplink communication band is allocated within any frame of the plurality of frames included during the count period and a band allocation position among the frames from the OLT, and the ONU transmits the uplink frame to the OLT based on the number of counts of the uplink frame counter, the frame identifier, and the band allocation position among the frames and stops the transmission of the uplink frame between the timings where the other OLT of the system allocates the uplink communication band to the other ONU of the system.
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19. An OLT that is connected to an ONU and the other ONU of a system through an optical fiber shared by the ONU and the other ONU of the system, is further connected to the other OLT of the system, and transmits data between the ONUs,
wherein the OLT shares uplink communication band information that is allocated to the ONU and the other ONU of the system with the other OLT of the system, and the OLT allocates the uplink communication band to the ONU by avoiding the communication band that is allocated to the other OLT of the system.
Specification