JP2009141889A - Optical communication network system, subscriber side device, and station side device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an optical communication network system, a subscriber side device, and a station side device capable of effectively using an uplink transmission path band and excellent in transmission path efficiency. <P>SOLUTION: The system comprises a buffer in which the subscriber side device accumulates uplink data transmitted from a user device connected to the subscriber side device, a buffer state monitoring part that monitors the accumulation state of data in the buffer and generates information about the amount of data, and a subscriber side control part that determines whether or not to issue a request to the station side device for an uplink transmission band for transmitting a dedicated frame to notify the station side device of the information about the amount of data based on the information about the buffer state and based on this determination result, notifies the station side device of information about the band request for a dedicated frame band that requests the uplink transmission band for the dedicated frame, or information indicating that no dedicated frame is necessary which does not request the uplink transmission band for the dedicated frame together with the information about the amount of data using either the dedicated frame or data frame. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical communication network system, a subscriber apparatus, and a station-side apparatus, and in particular, a subscriber-side apparatus among control frames such as a GATE frame and a REPORT frame exchanged between the subscriber-side apparatus and the station-side apparatus. The present invention relates to an optical communication network system, a subscriber-side device, and a station-side device that can effectively use an upstream transmission band by reducing the number of transmissions of REPORT frames transmitted from the device to the station-side device.

  Conventionally, a point-multipoint optical transmission system (optical burst transmission / reception network) generally referred to as a PON (Passive Optical Network) system is used in an access network for transmitting a multimedia service or the like to each home. In the PON system, a station side device (OLT: Optical Line Terminal) notifies each subscriber side device (ONU: Optical Network Unit) of the transmission start time and transmission amount of each subscriber device using a GATE frame, Each subscriber side device notifies the station side device of the amount of data waiting for transmission stored in its own buffer using the REPORT frame, so that each subscriber side device does not collide in time. Transmission control in the upstream direction (direction from the subscriber side device to the station side device) is performed so that transmission is possible (see Non-Patent Document 1, for example).

IEEE Std 802.3-2005 section 64

  However, according to the above conventional technique, the station side device is connected to each subscriber side device because it performs uplink transmission control by exchanging the GATE frame and the REPORT frame individually. As the number of subscriber side devices increases, the amount of GATE frames and REPORT frames increases, and there is a problem that the bandwidth of the transmission path cannot be used effectively. Especially for data transmission in the upstream direction, overhead for burst control such as “Laser ON”, “syncTime”, and “Laser OFF” is added (IEEE802.3-2005 section 64, Fig.64-32). There has been a problem that the reduction in efficiency appears remarkably.

  The present invention has been made in view of the above, and is an optical communication network system excellent in transmission path efficiency capable of effectively using an upstream transmission path band (from a subscriber side apparatus to a station side apparatus). An object is to obtain a subscriber unit and a station side unit.

  In order to solve the above-described problems and achieve the object, an optical communication network system according to the present invention includes a station-side device and a plurality of subscriber-side devices connected via an optical transmission line, and the station-side device and the An optical communication network system that performs bidirectional communication between a plurality of subscriber side devices, a buffer unit that accumulates data to be transmitted in an uplink direction transmitted from a user device connected to the own device, and a buffer unit in the buffer unit A buffer status monitoring unit that monitors data accumulation status and generates data amount information; and uplink transmission for transmitting a dedicated frame for notifying the station side device of the data amount information based on the buffer status information Determining whether to request a bandwidth to the station side device, based on the determination result, dedicated frame bandwidth request information for requesting the uplink transmission bandwidth for the dedicated frame, or A subscriber-side control unit for notifying the station-side device together with data amount information using either the dedicated frame or the data frame, the dedicated frame bandwidth unnecessary information that does not require an upstream transmission band for the frame, The station side device, from a dedicated frame or data frame received from the subscriber side device, a data amount information extraction unit for extracting the data amount information, and from a dedicated frame or data frame received from the subscriber side device, A request information extraction unit that extracts a dedicated frame bandwidth request or dedicated frame bandwidth unnecessary information as to whether or not the subscriber-side device requests allocation of an uplink transmission band for the dedicated frame, and the extracted data amount Based on the information, the uplink transmission band for the data frame to be allocated to the subscriber side device is determined, and the determination result When notifying the subscriber side device and determining whether to allocate an uplink transmission band for the dedicated frame based on the extracted request information, and determining to allocate the uplink transmission band for the dedicated frame Comprises a station side control unit for notifying the subscriber side device of the uplink transmission band to be allocated.

  According to the present invention, the number of transmissions of a dedicated frame for information on the amount of data stored in the buffer can be reduced, and the transmission efficiency decreases in the upstream direction (from the subscriber side device to the station side device) due to the dedicated frame transmission. As a result, it is possible to obtain a PON optical communication network system with excellent transmission path efficiency that can effectively use the upstream transmission path band.

  Embodiments of an optical communication network system, a subscriber unit, and a station side device according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably.

Embodiment FIG. 1 is a diagram showing a schematic configuration of a PON system which is an optical communication network system according to an embodiment of the present invention. In FIG. 1, a station-side device 100 is connected to an optical coupler 2 by an optical fiber 1 and n subscriber-side devices 200 are connected to the optical coupler 2 by optical fibers 3 to constitute a PON system.

  The subscriber apparatus 200 includes an optical transmission / reception unit 201, a PON control unit 202, a buffer unit 203, a network interface unit 204, a buffer unit 205, and a buffer state monitoring unit 206. The network interface unit 204 interfaces with the user home device. The buffer unit 203 accumulates data from the user home device. The buffer unit 205 accumulates data from the PON control unit 202. The buffer status monitoring unit 206 monitors the status of the buffer unit 203.

The PON control unit 202 is stored in the buffer unit 203 based on the function of outputting the data stored in the buffer unit 203 to the optical transmission / reception unit 201 in accordance with an instruction from the station side device 100 and the information of the buffer state monitoring unit 206. A function of notifying the amount of data (REPORT information notification function) and a function of outputting data from the optical transmission / reception unit 201 to the buffer unit 205 are provided.
The optical transceiver 201 converts an electrical signal and an optical signal.

  On the other hand, the station-side device 100 includes an optical transmission / reception unit 101, a PON control unit 102, a buffer unit 103, a network interface unit 104, a buffer unit 105, and a REPORT information extraction unit 106. The optical transceiver 101 converts an optical signal and an electrical signal. The REPORT information extraction unit 106 extracts REPORT information from the data output from the optical transmission / reception unit 101. The PON control unit 102 determines whether to allocate a REPORT frame band to the subscriber-side device 200 based on a function of outputting data from the REPORT information extraction unit 106 to the buffer unit 103 and an instruction from the REPORT information extraction unit 106 A GATE frame for instructing an uplink allocation band (specifically, uplink transmission start time and transmission amount) so that the subscriber apparatus 200 can transmit to the subscriber apparatus 200 without colliding in time. A function of generating data, and a function of outputting output data from the buffer unit 105 to the optical transmission / reception unit 101.

  The buffer unit 103 accumulates output data from the PON control unit. The buffer unit 105 accumulates data from the network interface unit 104. The network interface unit 104 interfaces with a host network device. Here, the REPORT information indicates the amount of data stored in the buffer unit 203 notified by the subscriber side device.

  FIG. 2 is a flowchart showing a processing flow of the REPORT information notification function of the PON control unit 202 in the present embodiment. The amount of data stored in the buffer 203 of the subscriber side device 200 is stored in the station side device 100. As a notification means, a processing flow for determining whether to notify using a normal REPORT frame or to embed notification in data transmitted by the user home device is shown.

  FIG. 3A is a diagram showing an example of a frame format in the case where the data storage amount in the buffer 203 of the subscriber-side device 200 is embedded in the data transmitted by the user home device and notified to the station-side device 100. is there. In this example, the data accumulation amount of the queue in the buffer 203 is embedded in the preamble area of the Ethernet (registered trademark) frame. However, for example, the main signal data part other than the preamble part may be expanded and embedded.

  FIG. 3B is a diagram showing an example of the frame format of a normal REPORT frame. The PON control unit 202 can notify the station-side device 100 of the data amount stored in the buffer 203 of the subscriber-side device 200 using either of these two frame formats.

  Both the frame formers shown in FIGS. 3A and 3B have a “Report bandwidth request bit” for identifying whether or not to request the next REPORT frame bandwidth, and when this bit is “ON”. Requesting the next REPORT frame bandwidth is used to indicate that the next REPORT frame bandwidth is not requested in the case of “OFF”.

  Next, the operation of the PON system according to this embodiment will be described. FIG. 4 is an operation explanatory diagram showing a transmission control method in the upstream direction (direction from the subscriber side apparatus 200 to the station side apparatus 100) in the PON system according to the present embodiment. For ease of understanding, it is assumed here that there are only two queues in the buffer unit 203, queue # 1 and queue # 2.

  First, the station apparatus 100 notifies the transmission start time and the transmission amount of each subscriber apparatus using the GATE frame. FIG. 4A shows a case where there is no accumulated data in the buffer unit 203 of the subscriber side apparatus 200, that is, a case where there is no accumulated data in both the queue # 1 and the queue # 2 (step S11 in the processing flow of FIG. 2). Corresponding to the flow of “YES”).

  In this case, since there is no data to be transmitted from the subscriber side device 200 in the upstream direction (direction from the subscriber side device 200 to the station side device 100), the PON control unit 202 sets the REPORT bandwidth request bit to “ON”. The set normal REPORT frame (REPORT bandwidth request notification) is transmitted to the station side device via the optical transceiver 201 (corresponding to step S23 in FIG. 2).

  In the station side device 100, the optical transmission / reception unit 101 receives the normal REPORT frame transmitted from the subscriber side device 200, converts the optical signal into an electrical signal, and outputs it to the REPORT information extraction unit 106. Upon receiving this normal REPORT frame, the REPORT information extraction unit 106 of the station apparatus 100 detects that the REPORT bandwidth request bit is “ON”, and the REPORT information and the REPORT bandwidth request bit are “ON”. This is notified to the PON control unit 102. In response to this notification, the PON control unit 102 transmits a GATE frame to which only the bandwidth for the REPORT frame is allocated to the subscriber side apparatus 200 via the optical transmission / reception unit 101.

  FIG. 4B shows a case where a transition is made from the state of FIG. 4A to the state where data is stored in the queue # 1 in the buffer unit 203 of the subscriber side device 200 (step S11 in FIG. 2). (Corresponding to the flow of branch “No” and branch “YES” in step S12). In this case, since data to be transmitted in the upstream direction from the subscriber-side device 200 is accumulated in the buffer unit 203, the PON control unit 202 sets a normal REPORT frame (REPORT frame with the REPORT bandwidth request bit set to “OFF”. A band unnecessary notification) is transmitted to the station side apparatus 200 via the optical transmission / reception unit 201 (corresponding to step S22 in FIG. 2).

  In the station side device 100, the optical transmission / reception unit 101 receives the normal REPORT frame transmitted from the subscriber side device 200, converts the optical signal into an electrical signal, and outputs it to the REPORT information extraction unit 106. Upon receiving this normal REPORT frame, the REPORT information extraction unit 106 of the station apparatus 100 detects that the REPORT bandwidth request bit is “OFF”, and the REPORT information and the REPORT bandwidth request bit are “OFF”. This is notified to the PON control unit 102. Upon receiving this notification, the PON control unit 102 sends a GATE frame for allocating only the data band stored in the queue # 1 in the buffer unit 203 to the subscriber apparatus 200 via the optical transmission / reception unit 101. Send.

  FIG. 4C shows a case where more data is accumulated in the queue # 1 in the buffer unit 203 of the subscriber side device 200 from the state of FIG. 4B (the branch “in step S11” in FIG. 2). No ”, branch“ NO ”in step S12, and branch“ YES ”in step S13). In this case, since data to be transmitted in the upstream direction from the subscriber side device 200 is accumulated in the buffer unit 203, the PON control unit 202 sets the REPORT bandwidth request bit to “OFF” and outputs the data. The REPORT information is embedded in the data frame (REPORT band unnecessary notification) is transmitted to the station-side apparatus 200 via the optical transceiver 201 (corresponding to step S21 in FIG. 2).

  In the station side device 100, the optical transmission / reception unit 101 receives the data frame transmitted from the subscriber side device 200, converts the optical signal into an electrical signal, and outputs it to the REPORT information extraction unit 106. Upon receiving this data frame, the REPORT information extraction unit 106 of the station side device 100 detects that the REPORT bandwidth request bit is “OFF” and that the REPORT information is embedded, and the REPORT information is extracted from the data frame. And the PON control unit 102 is notified that the REPORT information and the REPORT bandwidth request bit are “OFF”. Upon receiving this notification, the PON control unit 102 sends a GATE frame for allocating only the data band stored in the queue # 1 in the buffer unit 203 to the subscriber apparatus 200 via the optical transmission / reception unit 101. Send.

  In FIG. 4D, data is still accumulated in the queue # 1 in the buffer unit 203 of the subscriber apparatus 200 from the state of FIG. 4C, and new data is accumulated in the queue # 2. (Corresponding to the branch “No” in step S11 of FIG. 2, the branch “NO” in step S12, the branch “NO” in step S13, and the branch “NO” in step S14). . In this case, since there is no means for notifying the REPORT information about the data newly accumulated in the queue # 2 in the buffer unit 203, the PON control unit 202 is output when data is output from the queue # 1 in the buffer unit 203. Transmits the data frame (REPORT bandwidth request notification) in which the REPORT information is embedded in the output data to the station side device 200 via the optical transmission / reception unit 201. (Corresponding to step S20 in FIG. 2).

  In the station side device 100, the optical transmission / reception unit 101 receives the data frame transmitted from the subscriber side device 200, converts the optical signal into an electrical signal, and outputs it to the REPORT information extraction unit 106. Upon receiving this data frame, the REPORT information extraction unit 106 of the station side device 100 detects that the REPORT bandwidth request bit is “ON” and that the REPORT information is embedded, and the buffer unit from the data frame is detected. The REPORT information of the queue # 1 in 203 is extracted, and the PON control unit 102 is notified that the REPORT information and the REPORT bandwidth request bit are “ON”. Upon receiving this notification, the PON control unit 102 sends a GATE frame for allocating both the data band and the REPORT frame band stored in the queue # 1 in the buffer unit 203 via the optical transmission / reception unit 101. To the side device 200.

  FIG. 4E shows a case where data is still stored in the queue # 1 and the queue # 2 in the buffer unit 203 of the subscriber side apparatus 200 without changing from the state of FIG. 4D. 2 (corresponding to the branch “NO” in step S11, the branch “NO” in step S12, the branch “NO” in step S13, and the branch “YES” in step S14).

  In FIG. 4D, since the bandwidth for the queue # 1 accumulated data in the buffer unit 203 and the bandwidth for the REPORT frame are allocated to the subscriber side device 200, the PON control unit 202 uses the REPORT frame to A bandwidth for the data stored in queue # 1 and queue # 2 in 203 is requested. Also, a data frame in which REPORT information is embedded in the data accumulated in the queue # 1 in the buffer unit 203 in the data band is output.

  At this time, since the data to be output is still accumulated in the queue # 1 and the queue # 2 in the buffer unit 203 after the data is output, the REPORT bandwidth request bit is set to “OFF” for both the REPORT frame and the data frame. To the station side device (REPORT band unnecessary notification, corresponding to step S22 in FIG. 2).

  In the station apparatus 100, the optical transmitter / receiver 101 receives the REPORT frame in which the REPORT bandwidth request bit transmitted from the subscriber apparatus 200 is “OFF” and embedded with the REPORT information, and converts the optical signal into an electrical signal. The data is converted and output to the REPORT information extraction unit 106. When receiving the REPORT frame, the REPORT information extracting unit 106 of the station side device 100 detects that the REPORT bandwidth request bit is “OFF” and that the REPORT information is embedded, and the buffer unit from the data frame is detected. The REPORT information of queue # 1 and queue # 2 in 203 is extracted, and the PON control unit 102 is notified that the REPORT information and the REPORT bandwidth request bit are “OFF”. Upon receiving this notification, the PON control unit 102 sends a GATE frame for allocating only the data band stored in the queue # 1 and the queue # 2 in the buffer unit 203 via the optical transmission / reception unit 101. 200 is transmitted.

  FIG. 4 (f) shows a case where no data is accumulated in the additional buffer unit 203 from the state of FIG. 4 (e) and all data can be output in the previously requested bandwidth (step S11 in FIG. 2). Branch “NO”, step S12 branch “NO”, step S13 branch “NO”, and step S14 branch “NO”). In this case, since all the data in the queue # 1 and the queue # 2 in the buffer unit 203 assigned in FIG. 4 (e) are output, the data from the queue # 1 and the queue # 2 in the buffer unit 203 is output. At the time of output, the REPORT bandwidth request bit is set to “ON”, and a data frame (REPORT bandwidth request notification) in which REPORT information is embedded in the output data is transmitted to the station side device (FIG. 2). Corresponding to step S20).

  In the station side device 100, the optical transmission / reception unit 101 receives the data frame in which the REPORT bandwidth request bit transmitted from the subscriber side device 200 is “ON” and embedded in the REPORT information, and the optical signal is converted into an electrical signal. The data is converted and output to the REPORT information extraction unit 106. Upon receiving this REPORT frame, the REPORT information extraction unit 106 of the station side device 100 detects that the REPORT bandwidth request bit is “ON” and that the REPORT information is embedded, and from each data frame, The REPORT information of queue # 1 and queue # 2 in the buffer unit 203 is extracted, and the PON control unit 102 is notified that the REPORT information and the REPORT bandwidth request bit are “ON”. Upon receiving this notification, the PON control unit 102 transmits a GATE frame to which only the REPORT frame band is allocated to the subscriber side apparatus 200 via the optical transmission / reception unit 101.

  As described above, in the present embodiment, when the data to be transmitted to the station side device 100 is accumulated in the queue in the buffer unit 203 of the subscriber side device 200, the PON control unit 202 Control is performed so that the REPORT frame is not transmitted from the subscriber apparatus 200 without transmitting the REPORT information to the data at the time of data transmission without requesting the frame band for the subscriber apparatus 200. Further, when data is accumulated in a new queue, the PON control unit 202 performs control to transmit a REPORT frame for the data from the subscriber apparatus 200. As a result, the number of transmissions of the REPORT frame can be reduced, and a reduction in transmission efficiency in the upstream direction (from the subscriber side apparatus to the station side apparatus) due to the transmission of the REPORT frame can be minimized. It is possible to realize a PON optical communication network system excellent in transmission path efficiency that can effectively use a transmission path band.

  As described above, the optical communication network system according to the present invention is useful for optical communication with excellent transmission path efficiency that effectively uses the upstream transmission path band.

It is a figure which shows schematic structure of the PON system which is an optical communication network system concerning embodiment of this invention. It is the flowchart which showed the processing flow of the REPORT information notification function of the PON control part in this Embodiment. It is the figure which showed the example of the frame format when notifying the data accumulation amount in the buffer of a subscriber side apparatus to the data transmitted by the user home apparatus to a station side apparatus. It is operation | movement explanatory drawing which showed the transmission control method of the uplink direction in the PON system concerning this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical fiber 2 Optical coupler 3 Optical fiber 100 Station side apparatus 101 Optical transmission / reception part 102 PON control part 103 Buffer part 104 Network interface part 105 Buffer part 106 REPORT information extraction part 200 Subscriber side apparatus 201 Optical transmission / reception part 202 PON control part 203 Buffer unit 204 Network interface unit 205 Buffer unit 206 Buffer status monitoring unit

Claims (5)

An optical communication network system in which a station-side device and a plurality of subscriber-side devices are connected via an optical transmission path, and performs bidirectional communication between the station-side device and the plurality of subscriber-side devices,
A buffer unit for accumulating data to be transmitted in the uplink direction transmitted from the user apparatus connected to the own apparatus;
A buffer status monitoring unit for monitoring data storage status in the buffer unit and generating data amount information;
Based on the buffer status information, it is determined whether or not to request the upstream transmission band for transmission of a dedicated frame for notifying the data amount information to the station side device, and the determination result Based on either the dedicated frame or the data frame, the dedicated frame band request information for requesting the uplink transmission band for the dedicated frame or the dedicated frame band unnecessary information for not requesting the uplink transmission band for the dedicated frame is used. A subscriber-side control unit for notifying the station-side device together with data amount information;
With
The station side device
A data amount information extraction unit for extracting the data amount information from a dedicated frame or data frame received from the subscriber side device;
A dedicated frame bandwidth request or a dedicated frame bandwidth is not required from the dedicated frame or data frame received from the subscriber side device whether or not the subscriber side device requests allocation of the uplink transmission band for the dedicated frame. A request information extraction unit for extracting information;
Based on the extracted data amount information, an uplink transmission band for a data frame to be allocated to the subscriber side device is determined, the determination result is notified to the subscriber side device, and based on the extracted request information Station-side control that determines whether or not to allocate an uplink transmission band for a dedicated frame, and notifies the subscriber-side device of the uplink transmission band to be allocated when it is determined that the uplink transmission band for the dedicated frame is allocated And
Providing
An optical communication network system. The subscriber side control unit uses the data frame when the data to be transmitted to the station side device is stored in the buffer unit and the uplink transmission band for the data frame is allocated. Notifying the station side device of the dedicated frame bandwidth request information or the dedicated frame bandwidth unnecessary information,
The optical communication network system according to claim 1. A subscriber-side device used in an optical communication network system in which a station-side device and a plurality of subscriber-side devices are connected via an optical transmission line and performs bidirectional communication between the station-side device and the plurality of subscriber-side devices Because
A buffer unit for accumulating data to be transmitted in the uplink direction transmitted from the user apparatus connected to the own apparatus;
A buffer status monitoring unit for monitoring data storage status in the buffer unit and generating data amount information;
Based on the buffer status information, it is determined whether or not to request the upstream transmission band for transmission of a dedicated frame for notifying the data amount information to the station side device, and the determination result Based on either the dedicated frame or the data frame, the dedicated frame band request information for requesting the uplink transmission band for the dedicated frame or the dedicated frame band unnecessary information for not requesting the uplink transmission band for the dedicated frame is used. A subscriber-side control unit for notifying the station-side device together with data amount information;
A subscriber-side device comprising: The subscriber side control unit uses the data frame when the data to be transmitted to the station side device is stored in the buffer unit and the uplink transmission band for the data frame is allocated. Notifying the station side device of the dedicated frame bandwidth request information or the dedicated frame bandwidth unnecessary information,
The subscriber-side device according to claim 3. A station-side device used in an optical communication network system in which a station-side device and a plurality of subscriber-side devices are connected via an optical transmission line, and bidirectional communication is performed between the station-side device and the plurality of subscriber-side devices. There,
A data amount information extraction unit for extracting information on the amount of data stored in the subscriber side device from the frame received from the subscriber side device;
Request information extraction for extracting, from the frame received from the subscriber side device, request information indicating whether or not the subscriber side device requests allocation of a dedicated frame band for the next notification of the data amount information. And
Based on the extracted data amount information, an uplink transmission band for a data frame to be allocated to the subscriber side device is determined, the determination result is notified to the subscriber side device, and based on the extracted request information A station that determines whether or not to allocate an uplink transmission band for the next dedicated frame, and notifies the subscriber side device of the uplink transmission band to be allocated if it is determined to allocate the uplink transmission band for the dedicated frame Side control unit,
A station-side device comprising:

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