JP6013299B2 - Station side apparatus and optical transmission system in optical transmission system - Google Patents

Description

  The present invention relates to a station in an optical transmission system that transfers frames between a plurality of subscriber-side devices (ONU: Optical Network Unit) and higher-level devices connected via an optical transmission line (PON). The present invention relates to an optical line terminal (OLT) and an optical transmission system, and more particularly to an OLT and an optical transmission system that enable efficient communication with a large number of ONUs.

  In 2009, standardization of 10G-EPON (10 Gigabit Ethernet Passive Optical Network: Ethernet is a registered trademark) was completed in IEEE 802.3av. The characteristic of 10G-EPON is that 10-times high-speed transmission is possible as compared with GE-PON (Gigabit Ethernet Passive Optical Network: see Non-Patent Document 1) that is already widely used. Furthermore, there is a feature that existing GE-PON and 10G-EPON can be used together.

  When using a mixture of GE-PON and 10G-EPON, WDM (Wavelength Division Multiplexing) technology using different wavelengths for 1G downlink signals and 10G downlink signals is used, and between 1G downlink signals and between 10G downlink signals, respectively. TDM (Time Division Multiplexing) technology is used. In the upstream signal, the same wavelength is used for the 1G upstream signal and the 10G upstream signal, and the 1G upstream signal and the 10G upstream signal are combined to use a TDMA (Time Division Multiple Access) technique. That is, three different wavelengths are used for the 1G downstream signal, the 10G downstream signal, and the upstream signal.

  FIG. 9 shows an outline of the configuration of a conventional GE-PON system. In the figure, 1 is an OLT (station side device), 2 is an optical splitter, 3 is an ONU (subscriber side device), and OLT 1 is a plurality of ONUs 3 connected via an optical splitter 2 and a host device (not shown). Frame).

  The GE-PON OLT 1 includes an optical transceiver 11 and a PON control circuit 12. In the OLT 1, the optical transceiver 11 performs electrical optical conversion of the downstream frame to the ONU 3 connected to the optical transceiver 11 and photoelectric electrical conversion of the upstream frame from the ONU 3.

  In the OLT 1, the maximum number of ONUs 3 that can be connected to one optical transceiver 11 is 32, which is defined by the IEEE standard. Therefore, when it is necessary to connect 33 or more ONUs 3 as a station that accommodates the ONU 3, a plurality of optical splitters 2 are provided between the OLT 1 and the ONU 3 as shown in FIG. A configuration using a plurality of PON control circuits 12 is a general configuration.

JP 2012-19353 A

"Technology Basic Course [GE-PON Technology] 1st PON", NTT Technical Journal, Vol.17, No.8, pp.71-74, 2005.

  Even in the 10G-EPON system, the maximum number of ONUs 3 that can be connected to one optical transceiver 11 is 32, which is defined by the IEEE standard. The PON control device for 10G-EPON is the PON control for GE-PON. Higher performance (10 times the data transfer rate) than the device is required, and the cost of the device (such as the purchase price of the device) also increases. Therefore, as a problem for adopting the 10G-EPON system, it is a problem to reduce the system cost per ONU as much as possible.

  As one of the countermeasures for the above problems, it is conceivable to reduce the number of optical transceivers and PON control circuits used by increasing the number of ONUs that can be connected to one optical transceiver. For example, a technique that enables connection of 33 or more ONUs by using an optical amplifier has been proposed (see, for example, Patent Document 1).

  However, the optical amplifier has a problem that the cost of the device (such as the purchase price of the device) is higher than that of a component for an electric circuit (such as LSI).

  The present invention has been made to solve such a problem, and an object of the present invention is to minimize the system cost per ONU in a PON system, particularly a 10G-EPON system.

In order to achieve such an object, the present invention provides a frame between a plurality of subscriber-side devices (ONUs) and higher-level devices connected via first to Nth (N ≧ 2) optical splitters. In the station side apparatus (OLT) in the optical transmission system for transfer processing, the downstream frame electricity to the ONUs connected to the first to Nth optical splitters on a one-to-one basis and connected to the first to Nth optical splitters. First to Nth (N ≧ 2) optical transceivers that perform optical conversion and photoelectric conversion of upstream frames from the ONU, and input / output of upstream frames to and from upstream devices, A PON control circuit that controls not to simultaneously transmit upstream frames to a plurality of ONUs connected to the 1st to Nth optical splitters, and one optical traffic from the upstream frame outputs of the 1st to Nth optical transceivers; And outputs against PON control circuit selects the upstream frame outputs of the receiver, and a selection and distribution circuit for outputting a downstream frame output of the PON control circuit with respect to the optical transceiver of the first to N, selects and The distribution circuit controls the operation of the selector on the basis of the selector connected between the first to Nth optical transceivers and the PON control circuit, and the upstream band allocation information from the PON control circuit. And a selector control circuit that selects the upstream frame output of one optical transceiver from the upstream frame outputs of the N optical transceivers and sends it to the PON control circuit .

  In the present invention, the OLT is composed of N optical transceivers, one PON control circuit, and one selection / distribution circuit. According to the IEEE standard, the maximum number of ONUs that can be connected to one optical transceiver is 32. Therefore, the configuration includes N optical transceivers, one PON control circuit, and one selection / distribution circuit. Thus, it becomes possible to accommodate N × 32 ONUs in the OLT. For example, when four optical transceivers are used, the OLT of the present invention can accommodate 4 × 32 = 128 ONUs.

  According to the present invention, since the OLT is configured by N optical transceivers, one PON control circuit, and one selection / distribution circuit, N × 32 ONUs can be accommodated in the OLT. This makes it possible to reduce the system cost per ONU in the PON system, particularly the 10G-EPON system, as much as possible.

It is a figure which shows the structural example of the PON system using 1st Embodiment (Embodiment 1) of the station side apparatus (OLT) in the optical transmission system which concerns on this invention. FIG. 3 is a diagram illustrating a configuration example of a selection / distribution circuit in the OLT according to the first embodiment. FIG. 10 is a diagram illustrating another configuration example of uplink (RX) of the selection / distribution circuit in the OLT according to the first embodiment. It is a figure which shows another structural example (1st example of a structure at the time of applying to a 10G-EPON system) of the selection distribution circuit in OLT of Embodiment 1. FIG. It is a figure which shows another structural example (2nd example of a structure at the time of applying to a 10G-EPON system) of the selection distribution circuit in OLT of Embodiment 1. FIG. 6 is a diagram illustrating a configuration example of uplink (RX) of a selection / distribution circuit in the OLT according to the second embodiment. FIG. FIG. 10 is a diagram illustrating a configuration example of a PON system using an OLT according to a third embodiment. FIG. 10 is a diagram illustrating a configuration example of a selection / distribution circuit in an OLT according to a third embodiment. It is a figure which shows the structural example of the conventional GE-PON system. It is a figure which shows another structural example of the conventional GE-PON system.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in the following description, what is not included in the scope of the right of the present invention is described as an embodiment, but here, it will be described as an embodiment.
[Embodiment 1]
FIG. 1 is a configuration example of a PON system using a first embodiment (embodiment 1) of a station side device (OLT) in an optical transmission system according to the present invention.

  In this PON system, the OLT 1 (1A) includes N (N ≧ 2: N is an integer of 2 or more) optical transceivers 11 (11-1 to 11-N), one PON control circuit 12, and 1 And a selection / distribution circuit 13.

  In the OLT 1A, one optical transceiver 11 is connected to one optical splitter 2 via an optical transmission line, and up to 32 ONUs 3 are commonly connected to one optical splitter 2 via the optical transmission line. ing. That is, the optical transceivers 11-1 to 11-N are respectively connected to the optical splitters 2-1 to 2-N via the optical transmission path, and the optical transmission paths are respectively connected to the optical splitters 2-1 to 2-N. Up to 32 ONUs 3 in total, N × 32 in total, are connected.

  This PON system is different from the conventional PON system shown in FIG. 10 in that there is one PON control circuit 12, and this PON control circuit 12 and N optical transceivers 11-1 to 11 are used. One selection / distribution circuit 13 is provided between −N.

  FIG. 2 shows a configuration example of the selection / distribution circuit 13 in the OLT 1A. The selection / distribution circuit 13 (13A) includes AND circuits AND1 to ANDN, an N-input OR circuit OR1, and a buffer circuit BF1.

  In the selection / distribution circuit 13A, the AND circuits AND1 to ANDN include the upstream frame outputs (denoted as RX in the drawing) of the optical transceivers 11-1 to 11-N and the LOS ( Loss of Signal) Inverted value of output is input. The LOS output is a signal indicating whether or not an optical signal is input to the optical transceiver 11, and is “1” when no optical signal is input, and “0” when an optical signal is input. "

  In the selection / distribution circuit 13A, the AND circuits AND1 to ANDN calculate the logical product of the upstream frame output of the optical transceivers 11-1 to 11-N and the inverted value of the LOS output, and the operation result (logical product value). To the N-input OR circuit OR1. The N-input OR circuit OR1 calculates a logical sum of N logical product values from the AND circuits AND1 to ANDN, and outputs the calculation result (logical sum value) to the PON control circuit 12 as upstream frame data.

  As described above, the LOS output is “1” when no optical signal is input to the optical transceiver 11, and is “0” when an optical signal is input. When the LOS outputs of the plurality of optical transceivers 11 do not become 0 simultaneously, that is, when only the LOS output of one optical transceiver 11 becomes 0, the optical transceiver 11 that outputs 0 as the LOS output The upstream frame output is output to the PON control circuit 12.

  Preventing the LOS outputs of the plurality of optical transceivers 11 from simultaneously becoming zero can be realized by controlling the PON control circuit 12 so that the plurality of ONUs 3 do not emit light (uplink frame transmission) simultaneously.

  Also in the conventional PON system, uplink band allocation (grant allocation) is performed so that a plurality of ONUs connected to the same optical splitter do not emit light (uplink frame transmission) at the same time.

  Also in the OLT 1A of the present embodiment, in the PON control circuit 12, a plurality of ONUs 3 do not emit light (upstream frame transmission) simultaneously to all the ONUs 3 connected to the optical splitters 2-1 to 2-N. That is, by performing upstream band allocation (grant allocation) so that only one ONU 3 emits light (upstream frame transmission), the LOS outputs of the plurality of optical transceivers 11 do not become zero simultaneously.

  Note that a registration request (Register Request) frame that is a control frame used for a request for connection of a new ONU or the like is permitted by the IEEE standard to allow a plurality of ONUs to simultaneously emit light (uplink frame transmission). Therefore, during the period (Discovery Window) in which the transmission of the registration request frame is permitted, the LOS outputs of the plurality of optical transceivers 11 may become 0 at the same time. The PON control circuit 12 may not be able to normally receive a registration request frame.

  However, during a period during which transmission of a registration request frame is permitted (Discovery Window), even in a conventional PON system, a plurality of ONUs connected to the same optical splitter simultaneously register with a registration request frame. In such a case, the OLT is designed to ignore (discard) a registration request frame that cannot be normally received. In the OLT 1A of the present embodiment, the specification is such that a registration request frame that cannot be normally received by the PON control circuit 12 may be ignored (discarded).

  On the other hand, in this selection / distribution circuit 13A, the downstream frame output (denoted as TX in the figure) of the PON control circuit 12 is output to all the optical transceivers 11-1 to 11-N via the buffer circuit BF1. (Distributed).

  As described above, the PON control circuit 12 in the OLT 1A is configured so that a plurality of ONUs 3 do not emit light (upstream frame transmission) simultaneously to all the ONUs 3 connected to the optical splitters 2-1 to 2-N. In addition to performing band allocation (grant allocation), frame transfer and the like are performed in the same manner as a PON control circuit of a conventional PON system.

  When the same optical transceiver 11 as that of the conventional PON system is used, the OLT 1A according to the present embodiment can communicate with a maximum of “N × 32” ONUs 3. For example, it is possible to communicate with a maximum of 128 units when N = 4 and with a maximum of 512 units when N = 16.

  FIG. 3 shows another configuration example of the uplink (RX) of the selection / distribution circuit 13A. In the selection / distribution circuit 13A ′, the same logic as that of the uplink (RX) in FIG. 2 is configured using selectors (Sel) # 1 to # 7 and AND circuits ♭ 1 to ♭ 4.

  In the configuration of FIG. 3, when the LOS outputs of all the optical transceivers 11 are 1, the selectors (Sel) # 1 to # 7 select and output the “1” side input. Therefore, the output of the optical transceiver 11-5 passes through the selectors (Sel) # 3, # 6, and # 7 and is output to the PON control circuit 12.

  Even when only the LOS output of the optical transceiver 11-5 is 0, the output of the optical transceiver 11-5 is output to the PON control circuit 12. When only the LOS output of the optical transceiver 11-4 is 0, the selector (Sel) # 2, the selector (Sel) # 5, and the selector (Sel) # 7 select and output the "0" side input. Therefore, the output of the optical transceiver 11-4 passes through the selectors (Sel) # 2, # 5, and # 7 and is output to the PON control circuit 12.

  Some of the selectors (Sel) also when the LOS output of only one of the optical transceivers (11-1 to 11-3 or 11-6 to 11-8) becomes 0 Selects and outputs the input on the “0” side, so that the output of the optical transceiver whose LOS output is 0 is output to the PON control circuit 12.

When the configuration of the OLT 1 shown in FIG. 1 is applied to a 10G-EPON system, it is necessary to consider the following points.
(1) An optical transceiver for 10G-EPON may have two outputs, 10 Gbit / s output and 1 Gbit / s output, as upstream frame outputs.
(2) When both the ONU for 10G-EPON and the ONU for GE-PON are connected to the same OLT, the PON control circuit outputs two outputs of 10 Gbit / s and 1 Gbit / s as downlink frame outputs. And both outputs must be output (distributed) to all optical transceivers.

  FIG. 4 shows, as an OLT 1B, a first example of the configuration of the OLT 1 when the configuration of the OLT 1A shown in FIG. 2 is applied to a 10G-EPON system.

  In this example, the optical transceivers 11-1 to 11-N include an output port for 10 Gbit / s and an output port for 1 Gbit / s as output ports for upstream frames, and 10 Gbit as an input port for downstream frames. It is assumed that an input port for / s and an input port for 1 Gbit / s are provided.

  In this example, the PON control circuit 12 has a configuration in which the upstream frame input can handle both 10 Gbit / s and 1 Gbit / s inputs, and an output port for 10 Gbit / s as an output port of the downstream frame. It is assumed that a port and an output port for 1 Gbit / s are provided.

  Further, the PON control circuit 12 recognizes whether frame transmission at 10 Gbit / s or frame transmission at 1 Gbit / s is permitted at the time of uplink band allocation, and the information is selected as a 10G_1G selection signal. It is assumed that it is configured to output to the distribution circuit 13 (13B).

  In the OLT 1B, the selection / distribution circuit 13 (13B) includes selectors SL1 to SLN, AND circuits AND1 to ANDN, an N-input OR circuit OR1, and buffer circuits BF1 and BF2.

  In this selection / distribution circuit 13B, the selectors SL1 to SLN receive the 10G_1G selection signal from the PON control circuit 12 and output the optical transceivers 11-1 to 11-11 as upstream frame outputs of the optical transceivers 11-1 to 11-N. Select an upstream frame from one of the output ports for -G 10 Gbit / s and 1 Gbit / s and send it to AND circuits AND1 to ANDN.

  Further, in the selection / distribution circuit 13B, a downstream frame (a 10 Gbit / s downstream frame output) from the 10 Gbit / s output port of the PON control circuit 12 is sent to all the optical transceivers 11-1 to 11-1 via the buffer BF1. It is output (distributed) to the input port for 11-N 10 Gbit / s.

  Downstream frames from the 1 Gbit / s output port of the PON control circuit 12 (downstream frame output of 1 Gbit / s) are sent through the buffer BF2 to 1 Gbit / s of all the optical transceivers 11-1 to 11-N. Output (distributed) to the input port.

  FIG. 5 shows, as an OLT 1C, a second example of the configuration of the OLT 1 when the configuration of the OLT 1A shown in FIG. 2 is applied to a 10G-EPON system.

  In this example, the optical transceivers 11-1 to 11-N include an output port for 10 Gbit / s and an output port for 1 Gbit / s as output ports for upstream frames, and 10 Gbit as an input port for downstream frames. It is assumed that an input port for / s and an input port for 1 Gbit / s are provided.

  In this example, the PON control circuit 12 includes an input port for 10 Gbit / s and an input port for 1 Gbit / s as an input port for an upstream frame, and an output port for 10 Gbit / s as an output port for a downstream frame. Output port and an output port for 1 Gbit / s.

  In the OLT 1C, the selection / distribution circuit 13 (13C) includes an RX_10G selection circuit 131, an RX_1G selection circuit 132, and buffer circuits BF1 and BF2. The RX_10G selection circuit 131 and the buffer circuit BF1 constitute a first selection / distribution circuit referred to in the present invention, and the RX_1G selection circuit 132 and the buffer circuit BF2 constitute a second selection / distribution circuit referred to in the present invention. Is configured.

  In this selection / distribution circuit 13C, the RX_10G selection circuit 131 has the same configuration as the uplink (RX) in FIG. 2 or FIG. 3, and outputs for 10 Gbit / s of the optical transceivers 11-1 to 11-N. The upstream frame output of one optical transceiver 11 is selected from the upstream frame output from the port (upstream frame output of 10 Gbit / s), and is sent to the 10 Gbit / s input port of the PON control circuit 12.

  The RX_1G selection circuit 132 has the same configuration as that of the uplink (RX) in FIG. 2 or FIG. 3, and outputs an upstream frame from the output port for 1 Gbit / s of the optical transceivers 11-1 to 11-N. The upstream frame output of one optical transceiver 11 is selected from (1 Gbit / s upstream frame output) and is sent to the 1 Gbit / s input port of the PON control circuit 12.

  Further, in this selection / distribution circuit 13C, the downstream frame from the output port for 10 Gbit / s of the PON control circuit 12 (downstream frame output of 10 Gbit / s) is transmitted to all the optical transceivers 11-1 via the buffer BF1. It is output (distributed) to an input port for 10 Gbit / s of ˜11-N.

  Downstream frames from the 1 Gbit / s output port of the PON control circuit 12 (downstream frame output of 1 Gbit / s) are sent through the buffer BF2 to 1 Gbit / s of all the optical transceivers 11-1 to 11-N. Output (distributed) to the input port.

  Here, the system cost per ONU of the PON system using the OLT 1 (OLT 1A, 1B, 1C) of the first embodiment described above is compared with the conventional PON system.

  Compared with the configuration of the OLT 1 using the N PON control circuits 12 in the configuration of FIG. 10, the configuration of the OLT 1 (OLT 1A, 1B, 1C) of the present embodiment has an additional selection / distribution circuit 13 added. However, the number of PON control circuits 12 is small.

  When the cost of the selection / distribution circuit 13 (the price of necessary parts, the increase in the board price due to the increase in the board area accompanying the increase in the number of parts, etc.) is compared with the cost of the PON control circuit 12, Is less than the cost of the PON control circuit 12. In particular, when the configuration shown in FIG. 3 is used, it is possible to use small parts at a low price, so that the cost can be further reduced.

  Further, in the case of the 10G-EPON system, it is assumed that the price of the PON control circuit 12 is larger than that of the PON-control circuit 12 for GE-PON, so that the cost advantage of the selection / distribution circuit 13 is greater. Become.

  Thereby, by adopting a configuration like the OLT 1 (OLT 1A, 1B, 1C) of the present embodiment, the system cost per ONU can be made smaller than that of the conventional PON system.

[Embodiment 2]
Next, the OLT according to the second embodiment will be described with reference to FIG. FIG. 6 is a diagram illustrating a configuration example of the uplink (RX) of the selection / distribution circuit 13D in the OLT 1 (1D) of the second embodiment.

  The difference from the configuration of FIG. 3 is that the selector (Sel) is controlled not using the LOS output of the optical transceiver 11 but using the uplink band allocation information output from the PON control circuit 12. For this reason, the selector / distributor circuit 13D is provided with a selector control circuit 133 for controlling the operations of the selectors (Sel) # 1 to # 7.

  Since the PON control circuit 12 performs upstream bandwidth allocation (frame transmission permission) for each ONU 3, if the optical transceiver 11 is connected to which optical transceiver 11 is connected, the signal from the ONU 3 that has permitted frame transmission is transmitted to the PON control circuit 12. The operations of the selectors (Sel) # 1 to # 7 can be controlled so as to output the signal.

  For example, when the ONU 3 is installed, the correspondence between the individual ID (MAC address or other serial number) of the ONU 3 and the optical transceiver 11 to be connected can be set for the selector control circuit 133.

As another method for setting which optical transceiver 11 the ONU 3 is connected to, the following method is also available.
(1) Selector (Sel) so that only the input from one specific optical transceiver 11 is output to the PON control circuit 12 during a period (Discovery Window) in which transmission of a registration request frame is permitted # 1 to # 7 are set.
(2) The MAC address of the ONU 3 that transmitted the registration request frame during the setting period is associated with the ID of the specific optical transceiver 11.
(3) ONU 3 connected to all optical transceivers 11 by periodically changing the settings of selectors (Sel) # 1 to # 7 in a period (Discovery Window) in which transmission of a registration request frame is permitted. It is possible to correspond to the reception of a registration request frame from the optical transceiver 11 and the ID of the optical transceiver 11 to which the MAC address of each ONU 3 is connected.

  In the selection / distribution circuit 13D, the selector control circuit 133 sets the selectors (Sel) # 1 to # 7 based on the upstream band allocation information from the PON control circuit 12 according to the setting of the connection relationship between the ONU 3 and the optical transceiver 11. The operation is controlled, and the uplink frame output of one optical transceiver 11 is selected from the uplink frame outputs of the optical transceivers 11-1 to 11-8, and is sent to the PON control circuit 12.

  In the second embodiment, similarly to the first embodiment, when the same optical transceiver 11 as that of the conventional PON system is used, communication with “N × 32” ONUs 3 at the maximum is possible. . For example, it is possible to communicate with a maximum of 128 units when N = 4 and with a maximum of 512 units when N = 16.

  In addition, the configuration of the second embodiment can be applied to a 10G-EPON system. Regarding the system cost per ONU, the configuration of the second embodiment is equivalent to the configuration of the first embodiment, and the cost is lower than the conventional configuration.

[Embodiment 3]
Next, the OLT according to the third embodiment will be described with reference to FIGS.
FIG. 7 is a configuration example of a PON system using the OLT 1 (1E) according to the third embodiment. The difference from the configuration of FIG. 1 is that two PON control circuits 12 are connected to the selection / distribution circuit 13. In this example, the PON control circuit 12A is provided as an operational PON control circuit (first PON control circuit), and the PON control circuit 12B is provided as a spare PON control circuit (second PON control circuit) 12B. .

  FIG. 8 is a diagram illustrating a configuration example of the selection / distribution circuit 13 (13E) in the OLT 1E. The difference from the configuration in FIG. 2 is that the output (upstream frame output) of the N-input OR circuit OR1 is output to the two PON control circuits 12A and 12B, and the two PON control circuits 12A and 12B. The selector (Sel) 134 that selects any one of the downstream frame outputs as a downstream frame to the optical transceivers 11-1 to 11-N and the operation of the selector 134 in response to the notification from the PON control circuits 12A and 12B The selector control circuit 135 is built in.

  The OLT 1E of the present embodiment is equipped with two PON control circuits 12A and 12B, one of which is reserved. In this example, the PON control circuit 12B is reserved. The PON control circuit 12A notifies the selector control circuit 135 that it is in the operating state, and the spare PON control circuit 12B notifies the selector control circuit 135 that it is in the spare state.

  The selector control circuit 135 controls the operation of the selector 134 so as to select the downstream frame output of the PON control circuit 12A in the operating state. As a result, the downstream frame output of the PON control circuit 12A selected by the selector 134 is sent to the optical transceivers 11-1 to 11-N.

  In this state, when a failure occurs in the PON control circuit 12A, the PON control circuit 12A notifies the selector control circuit 135 that the failure has occurred, and changes the PON control circuit 12B from the standby state to the operation state. Instruct. The PON control circuit 12B receives an instruction to change from the PON control circuit 12A to the operation state and notifies the selector control circuit 135 that the operation state has been changed from the standby state.

  After confirming that the PON control circuit 12B has changed to the operating state, the selector control circuit 135 controls the operation of the selector 134 so as to select the downstream frame output of the PON control circuit 12B that has been changed to the operating state. As a result, the downstream frame output of the PON control circuit 12B selected by the selector 134 is sent to the optical transceivers 11-1 to 11-N.

  In this manner, in the OLT 1E of the present embodiment, since the PON control circuit 12A in operation is switched to the standby PON control circuit 12B, the board on which the PON control circuit 12A is mounted during operation in the PON control circuit 12B. By configuring the system so that the exchange can be performed, the period during which communication is stopped due to a failure of the PON control circuit 12A or the like can be minimized.

  The OLT 1E of the present embodiment has the same effect as the OLT 1A of the first embodiment because the basic configuration is the same as that of the OLT 1A of the first embodiment.

[Extension of the embodiment]
The present invention has been described above with reference to the embodiment. However, the present invention is not limited to the above embodiment. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the technical idea of the present invention. Each embodiment can be implemented in any combination within a consistent range.
For example, the present invention can be applied to PON systems other than GE-PON and 10G-EPON.

  1 (1A to 1E): OLT (station side equipment), 2 (2-1 to 2-N): optical splitter, 3 ... ONU (subscriber side equipment), 11 (11-1 to 11-N): light Transceiver, 12 (12A, 12B) ... PON control circuit, 13 (13A-13E) ... selection / distribution circuit, AND1-ANDN ... AND circuit, OR1 ... N-input OR circuit, BF1, BF2 ... buffer circuit, SL1-SLN ... Selector 131... RX_10G selection circuit 132... RX_1G selection circuit 133... Selector control circuit 134.

Claims (2)

In a station-side device in an optical transmission system that transfers frames between a plurality of subscriber-side devices and higher-order devices connected via first to Nth (N ≧ 2) optical splitters,
A one-to-one connection to the first to N-th optical splitters, and a downstream frame electro-optical conversion to the subscriber-side devices connected to the first to N-th optical splitters and from the subscriber-side devices First to N-th optical transceivers for performing photoelectric conversion of the upstream frame,
Input and output upstream frames to and from the host device and simultaneously transmit upstream frames to the plurality of subscriber-side devices connected to the first to Nth optical splitters. A PON control circuit for controlling so as not to
The upstream frame output of one optical transceiver is selected from the upstream frame outputs of the first to Nth optical transceivers and output to the PON control circuit, and the downstream frame output of the PON control circuit is selected from the first to first optical transceivers. A selection / distribution circuit for outputting to the Nth optical transceiver ;
The selection / distribution circuit includes:
A selector connected between the first to Nth optical transceivers and the PON control circuit;
Based on the uplink bandwidth allocation information from the PON control circuit, the operation of the selector is controlled, the uplink frame output of one optical transceiver is selected from the uplink frame outputs of the first to Nth optical transceivers, and the PON A station-side device in an optical transmission system , comprising: a selector control circuit for sending to a control circuit . First to Nth (N ≧ 2) optical splitters, a plurality of subscriber-side devices connected to the first to Nth optical splitters, and a plurality connected to the first to Nth optical splitters In an optical transmission system comprising a station-side device that transfers a frame between a subscriber-side device and a host device,
The station side device
A one-to-one connection to the first to N-th optical splitters, and a downstream frame electro-optical conversion to the subscriber-side devices connected to the first to N-th optical splitters and from the subscriber-side devices First to N-th optical transceivers for performing photoelectric conversion of the upstream frame,
Input and output upstream frames to and from the host device and simultaneously transmit upstream frames to the plurality of subscriber-side devices connected to the first to Nth optical splitters. A PON control circuit for controlling so as not to
The upstream frame output of one optical transceiver is selected from the upstream frame outputs of the first to Nth optical transceivers and output to the PON control circuit, and the downstream frame output of the PON control circuit is selected from the first to first optical transceivers. A selection / distribution circuit for outputting to the Nth optical transceiver;
The selection / distribution circuit includes:
A selector connected between the first to Nth optical transceivers and the PON control circuit;
Based on the uplink bandwidth allocation information from the PON control circuit, the operation of the selector is controlled, the uplink frame output of one optical transceiver is selected from the uplink frame outputs of the first to Nth optical transceivers, and the PON Selector control circuit for sending to the control circuit
An optical transmission system characterized by that .

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