JP5546220B2 - Communication system and bandwidth allocation control method - Google Patents

Description

  The present invention relates to a communication system including a PON (Passive Optical Network) system and a host device such as L2SW (L2SW: Layer 2 SWitch) connected to the PON system, and a bandwidth allocation control method.

  In the PON system, in general, the PON system is connected to a higher level network via a higher level device such as a layer 2 switch arranged at a higher level of an OLT (Optical Line Terminal). First, as an example of a PON system, an EPON (Ethernet (registered trademark) PON) system standardized by IEEE (Institute of Electrical and Electronic Engineers) 802.3ah described in Non-Patent Document 1 below is taken as an example.

  In the EPON system, a logical link identifier (LLID: Logical Link ID (IDentifier)) is defined as an identifier indicating a logical connection on the PON system, and Ethernet (registered trademark) MAC (Media Access Control) is defined in units of the LLID. ) Frame transmission / reception control is performed. Also, in order to effectively use the upstream bandwidth, a dynamic bandwidth allocation method called DBA (Dynamic Bandwidth Allocation) is used as an access control method between the OLT and the ONU (Optical Network Unit: subscriber-side terminal device). .

A procedure for bandwidth allocation by DBA will be described below.
(1) When the ONU receives the uplink data from each terminal, the ONU accumulates the uplink data in a buffer in its own device.
(2) The ONU makes a bandwidth request by notifying the OLT of the amount of uplink data stored in the device itself using the REPORT frame in a batch (ONU unit) or LLID unit. Further, the OLT receives the REPORT frame to grasp the amount of uplink data stored in each ONU.
(3) The OLT is based on the accumulated data amount of the ONU (or LLID) notified in the REPORT frame and the bandwidth used by the other ONU (or LLID). Time).
(4) The OLT stores the value calculated in (3) as a band allocation result in the GATE frame and transmits it to the ONU.
(5) The ONU transmits uplink data at a specified time according to the band allocation result stored in the received GATE frame.

  The DBA has a mechanism in which a large number of bands are allocated to ONUs with many band requests by repeating the above (1) to (5).

  On the other hand, the L2SW connected to the PON system multiplexes data received from a plurality of PON systems and outputs the multiplexed data to the upper network. Since L2SW may exceed the bandwidth on the output line after multiplexing, the received frames are temporarily stored in a buffer in its own apparatus, and an algorithm such as WFQ (Weighted Fair Queuing) or SP (Strict Priority) is used. Bandwidth control is performed by reading a frame from the buffer. As a result, traffic concentration can be avoided to some extent.

  As described above, the PON system and the L2SW each perform bandwidth control. However, since the PON system and the L2SW operate independently, the DBA bandwidth allocation is performed regardless of the congestion state of the L2SW buffer. Therefore, if the ONU continues to request bandwidth, the OLT allocates that bandwidth, and as a result, even if the frame reaches the L2SW after performing bandwidth control in the PON system, it is wasted due to the overflow of the L2SW buffer. Disposal may occur.

  In order to avoid such a buffer overflow in L2SW, in Non-Patent Document 1, when congestion occurs in a port of L2SW, a PAUSE (pause) frame is transmitted to the opposite device of that port, and A method for instructing to temporarily stop transmission traffic is defined.

  Patent Document 1 below discloses a method for performing overall congestion control including a host network as follows. When the PON system is configured to connect to a higher-level network via a transfer device (GW: Gateway) that is a higher-level device, the GW detects congestion in units of output ports and notifies the OLT. Then, the OLT allocates a small bandwidth to the ONU that is congested during bandwidth allocation by the DBA.

  In addition, as a method for performing bandwidth control in cooperation with a host network, there is a method described in Patent Document 2 below. In the method of Patent Document 2 below, the OLT and the ONU monitor the amount of ONU accumulated data for each priority class, and receive the PAUSE frame to which the priority class queue number is assigned from the higher-level device. Is suspended / resumed for each priority class.

JP 2007-282037 A JP 2007-194732 A

IEEE, “IEEE Std 802.3ah-2008, Amendment: Media Access Control Parameters, Physical Layers, and Management Parameters for Subscriber Access Networks”, (Annex 31B)

  However, in the method described in Non-Patent Document 1, since congestion is detected in units of L2SW output ports, transmission traffic is temporarily stopped for all ONUs connected to the ports where congestion occurs. . For this reason, there is a problem that there is a possibility that an ONU frame that does not correspond to the congestion buffer of the L2SW may be temporarily stopped.

  In the method described in Patent Document 1, congestion is detected for each output port of the host device. Therefore, there is a problem that a small bandwidth is allocated to all ONUs connected to the congestion port, and the congestion cannot be controlled by the buffer storage unit of the host device.

  In the method described in Patent Document 2, traffic transfer is temporarily stopped / resumed for each priority class. However, the queue configuration (buffer configuration) of the L2SW is not limited to priority class units, but varies for each VLAN (Virtual Local Area Network), for each service, for each route, and the like. For this reason, there is a problem that frame discard due to buffer overflow of the host device cannot be prevented only by the method described in Patent Document 2.

  The present invention has been made in view of the above, and an object of the present invention is to provide a communication system and a bandwidth allocation control method capable of reducing frame discard.

In order to solve the above-described problems and achieve the object, the present invention provides a PON system composed of a station-side terminal device and a subscriber-side terminal device, and communication data between the PON system and an upper network. A host system that relays and performs QoS control, the host apparatus having a queue buffer for storing uplink data that is the communication data transmitted from the PON system to the host network An upstream queue buffer means provided for each QoS control unit, an upstream data distribution means for distributing the communication data received from the PON system for each QoS control unit and storing it in the corresponding queue buffer of the upstream queue buffer means, Congestion is monitored for each queue buffer, and the queue corresponding to the queue buffer in which congestion has occurred An uplink buffer congestion monitoring means for notifying a different child, and a control frame generating means for generating a control frame including the identifier notified by the uplink buffer congestion monitoring means and transmitting the control frame to the station-side terminal device, side terminating device, the identifier is extracted from the control frame, a control frame analysis means for determining a logical link identifier corresponding to the identifier as assigned negative logical identifier, the assignment exclusion logical identifier to the subscriber side terminating device Bandwidth allocation means for performing bandwidth allocation processing based on the communication data transmitted from a plurality of subscriber-side terminal devices in one of the queue buffers, and corresponding to one of the identifiers The allocation exclusion logical identifier is plural .

  According to the present invention, the host device that connects the host network and the PON system includes a queue buffer for each control unit, notifies the OLT of the identifier of the queue corresponding to the congested queue buffer, and the OLT transmits the congestion queue control frame. Since band allocation is performed excluding the LLID corresponding to the queue notified in (1), there is an effect that frame discard can be reduced. In addition, since the PON system reduces the transmission of frames that are discarded by the host device, the band can be used effectively.

FIG. 1 is a diagram illustrating a configuration example of a communication system according to the first embodiment. FIG. 2 is a diagram illustrating a functional configuration example of the L2SW according to the first embodiment. FIG. 3 is a diagram illustrating a functional configuration example of the PON-IF configuring the OLT according to the first embodiment. FIG. 4 is a diagram illustrating a functional configuration example of the ONU according to the first embodiment. FIG. 5 is an operation sequence diagram illustrating an example of the bandwidth allocation operation according to the first embodiment. FIG. 6 is a diagram illustrating a functional configuration example of the PON-IF configuring the OLT according to the second embodiment. FIG. 7 is a diagram illustrating a functional configuration example of the ONU according to the second embodiment. FIG. 8 is an operation sequence diagram illustrating an example of a bandwidth allocation operation according to the second embodiment. FIG. 9 is a diagram illustrating a configuration example of a communication system according to the third embodiment.

  Embodiments of a communication system and a bandwidth allocation control method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration example of a first embodiment of a communication system according to the present invention. As shown in FIG. 1, the communication system according to the present embodiment includes an L2SW1, an upper network 2 connected to the L2SW1, an OLT 4 connected to the L2SW, a coupler 5, and ONUs 6-1 to 6-n (n is 1). And the terminal 7.

  The OLT 4 is configured by PON-IF (Interface) 3-1 to 3-m (m is an integer of 1 or more). The L2SW1 multiplexes signals output from the PON-IFs 3-1 to 3-m, respectively. The PON-IF 3-2 of the OLT 4 is connected to the ONUs 6-1 to 6-n via the coupler 5 in a passive double star manner. Although not shown, an ONU is connected to a PON-IF other than the PON-IF6-2 via a coupler. The configuration in FIG. 1 is an example, and the number of terminals connected to the ONU 6-1 to ONU 6-n may be any number of zero or more.

  FIG. 2 is a diagram illustrating a functional configuration example of the L2SW 1 according to the present embodiment. As shown in FIG. 2, the L2SW 1 according to the present embodiment includes an upstream data receiving unit 11, an upstream data allocating unit 12, an upstream queue buffer unit 13, an upstream buffer reading control unit 14, an upstream data transmitting unit 15, an upstream buffer congestion. The monitoring unit 16 includes a congestion queue notification control frame generation unit 17, a downlink data transmission unit 18, a downlink data multiplexing unit 19, and a downlink data reception unit 20.

  The uplink data reception unit 11 performs a predetermined reception process on the signal received from the OLT 4 and outputs the signal to the uplink data distribution unit 12 as uplink data. The uplink data distribution unit 12 distributes the input uplink data for each QoS (Quality of Service) control unit (for example, priority class, VLAN, route, service, etc.), and a corresponding area of the uplink queue buffer unit 13 Store in (queue buffer). The upstream queue buffer unit 13 includes a queue buffer for each QoS control unit.

  The uplink buffer read control unit 14 reads the uplink data stored in the uplink queue buffer unit 13 and outputs it to the uplink data transmission unit 15. The uplink data transmission unit 15 performs a predetermined transmission process on the input uplink data and transmits it to the upper network 2.

The upstream buffer congestion monitoring unit 16 monitors the congestion state of each queue buffer of the upstream queue buffer unit 13 and performs congestion detection (or congestion release (congestion resolution) detection). There are various methods of congestion detection (or congestion release detection). For example, there are methods shown in (1) and (2) below, but not limited to these methods, any method may be used.
(1) A method in which a threshold is set in the queue buffer, and it is determined that congestion has been detected when the amount of data stored in the queue buffer exceeds the threshold.
(2) A method of measuring the number of buffer overflow frames within a predetermined time immediately before and determining that congestion has been detected when the number of buffer overflow frames exceeds a predetermined reference value.
The method is not specified in the present invention.

  Any method may be used as a congestion release detection method. For example, when the above (1) is used as a congestion detection method, when the amount of data stored in the queue buffer falls below a threshold value. Detect congestion release. Different threshold values may be used for congestion detection and congestion release detection.

  When the upstream buffer congestion monitoring unit 16 detects congestion (or detects congestion release), the upstream buffer congestion monitoring unit 16 distinguishes between congestion detection or congestion release detection and the type of the corresponding queue (for example, priority class, VLAN, route, service, etc.). The congestion queue notification control frame generation unit 17 is notified of the identifier of the corresponding queue (for example, the priority class number when the queue configuration is a priority class, or the VID (Virtual Local Area Network Identifier) when the queue configuration is VLAN unit). .

The congestion queue notification control frame generation unit 17, when notified from the upstream buffer congestion monitoring unit 16, the type of queue in which congestion is detected and the identifier of the queue, provides a control frame (congestion) for notifying the queue during congestion. Queue notification control frame) and the downlink data multiplexing unit 19
The data is transmitted to the OLT 4 via the downstream transmission unit 18. In addition, when the queue type and the queue identifier for which the congestion release is detected are notified from the uplink buffer congestion monitoring unit 16, a congestion queue notification control frame for notifying the release corresponding to the queue is generated, and the downlink data The data is transmitted to the OLT 4 via the multiplexing unit 19 and the downlink data transmission unit 18.

  The downlink data reception unit 20 performs a predetermined reception process on the downlink data received from the upper network 2 and outputs the processed downlink data to the downlink data multiplexing unit 19. The downlink data multiplexer 19 multiplexes the downlink data input from the downlink data receiver 20 and the congestion queue notification control frame input from the congestion queue notification control frame generator 17, and outputs the multiplexed data to the downlink data transmitter 18. The downlink data transmitter 18 transmits to the multiplexed data OLT 4.

  FIG. 3 is a diagram illustrating a functional configuration example of the PON-IF 3 configuring the OLT 4 according to the present embodiment. The PON-IFs 3-1 to 3-m shown in FIG. 1 have the same configuration. In FIG. 3, these are representatively described as PON-IF3.

  The PON-IF 3 includes an upstream data reception unit 31, an upstream data distribution unit 32, an upstream data transmission unit 33, a REPORT frame analysis unit 34, a DBA scheduler unit 35, a GATE frame generation unit 36, a congestion queue notification control frame analysis unit 37, A downlink data transmitting unit 38, a downlink data multiplexing unit 39, and a downlink data receiving unit 40 are provided.

  The downlink data reception unit 40 performs predetermined reception processing on the downlink data received from the L2SW1, detects a congestion queue notification control frame from the downlink data, and detects the detected congestion queue notification control frame as a congestion queue notification control frame analysis unit. 37, and outputs other downlink data to the downlink data multiplexing unit 39.

  If the congestion queue notification control frame is a frame for notifying a congestion queue (or congestion release) queue, the congestion queue notification control frame analysis unit 37 is in the congestion (or state) stored in the congestion queue notification control frame (or (Congestion release) queue type and queue identifier are mapped to LLID, which is a control unit of dynamic bandwidth allocation, and the LLID corresponding to the queue buffer during congestion (or congestion release) (the queue buffer of L2SW1), During congestion, the DBA scheduler unit 35 is notified of whether congestion is canceled or not.

Note that the correspondence between the ONU (LLID) and the queue configuration (buffer configuration) of the L2SW 1 may be, for example, the following three (A) to (C).
(A) ONU (LLID) and L2SW1 queue configuration (buffer configuration) corresponds to 1: 1 L2SW1 has a queue buffer for each LLID. For example, LLID and VID correspond one-to-one. Cases apply.
(A) The queue configuration (buffer configuration) of ONU (LLID) and L2SW1 corresponds to N (N is an integer equal to or greater than 2): 1.
This corresponds to a case where frames corresponding to a plurality of LLIDs are stored in one queue buffer by L2SW1.
(C) ONU (LLID) and L2SW1 queue configuration (buffer configuration) corresponds to 1: N A frame corresponding to one LLID is stored in a plurality of queue buffers in L2SW1, for example, L2SW1 is a priority class This corresponds to a case where a queue buffer is provided for each destination or a queue buffer is provided for each destination. The latter corresponds to the case where the destination can be identified by the service type, such as VoIP (Voice over Internet Protocol) and Internet access.

  The congestion queue notification control frame analysis unit 37 is a control frame analysis unit, and maps the type of queue being congested and the identifier of the queue to the LLID according to the above correspondence. For example, in the case of (a), one LLID is mapped to the queue in congestion, in the case of (b), the queue in congestion is mapped to a plurality of LLIDs, and in the case of (c), the queue being congested A queue will be mapped to one or more LLIDs.

  The uplink data receiving unit 31 performs uplink data reception from the ONU to which it is connected (ONUs 6-1 to 6-n in the case of the PON-IF 3-2 in FIG. 1) after performing a predetermined reception process. It outputs to the part 32. The uplink data distribution unit 32 distributes the input uplink data into the REPORT frame and other frames, outputs the REPORT frame to the REPORT frame analysis unit 34, and transmits the other frames to the uplink data transmission unit 33.

  As in the case of the conventional dynamic bandwidth allocation, the REPORT frame analysis unit 34 analyzes the REPORT frame input from the upstream data distribution unit 32 to grasp the amount of upstream data stored in each ONU, and the DBA The scheduler 35 is notified of the uplink data amount. The REPORT frame is a frame that includes the amount of data waiting to be transmitted (upstream data amount) that is transmitted from the ONU and accumulated in the buffer of the ONU.

  The DBA scheduler unit 35 is a bandwidth allocating unit. The uplink data amount notified from the REPORT frame analysis unit 34 and the congestion queue buffer (the L2SW1 queue buffer) notified from the congestion queue notification control frame analysis unit 37 are used. Based on the corresponding LLID, the dynamic bandwidth allocation control is performed by excluding the LLID corresponding to the queue buffer being congested in the L2SW1. For example, when the queue configuration of the above ONU (LLID) and L2SW1 is (a), one corresponding LLID is excluded, and when (a), a plurality of corresponding LLIDs are excluded. In this case, one or more corresponding LLIDs are excluded. In addition, when the congestion cancellation is notified, the DBA scheduler unit 35 performs dynamic bandwidth allocation control including the corresponding LLID.

  Then, the DBA scheduler unit 35 obtains a transmission start time and a transmission permission time to be allocated to each ONU as an allocation result by the dynamic band allocation control, and notifies the allocation result to the GATE frame generation unit 36. The GATE frame generation unit 36 generates a GATE frame based on the notified allocation result, and outputs the generated GATE frame to the downlink data multiplexing unit 39.

  The downlink data multiplexing unit 39 multiplexes the downlink data input from the downlink data reception unit 40 and the GATE frame input from the GATE frame generation unit 36 and outputs the multiplexed data to the downlink data transmission unit 38. The downlink data transmission unit 38 transmits the multiplexed data to the ONU to which it is connected.

  FIG. 4 is a diagram illustrating a functional configuration example of the ONU 6 according to the present embodiment. The ONUs 6-1 to 6-n shown in FIG. 1 have the same configuration, and in FIG. Also, when an ONU is connected to a PON-IF other than the PON-IF 3-2 of the OLT 4, the ONU configuration is the same as that in FIG.

  As shown in FIG. 4, the ONU 6 includes an upstream data receiving unit 61, an upstream data allocating unit 62, an upstream queue buffer unit 63, an upstream buffer reading control unit 64, an upstream data transmitting unit 65, a REPORT frame generating unit 66, an upstream scheduler. A unit 67, a GATE frame analysis unit 68, a downlink data transmission unit 69, a downlink data multiplexing unit 70, and a downlink data reception unit 71.

  The downlink data reception unit 71 performs predetermined reception processing on the downlink data received from the OLT 4, detects a GATE frame from the downlink data, outputs the detected GATE frame to the GATE frame analysis unit 68, and other downlink data Is output to the downlink data multiplexer 70.

  The GATE frame analysis unit 68 analyzes the input GATE frame and notifies the uplink scheduler unit 67 of the transmission start time and the transmission permission time stored in the GATE frame. The uplink scheduler unit 67 schedules transmission of uplink data based on the transmission start time and the transmission permission time notified from the GATE frame analysis unit 68, and transmits the uplink data to be transmitted from the uplink queue buffer unit 63 based on the scheduling result. The upstream buffer read control unit 64 is instructed to read. The uplink scheduler 67 also schedules the transmission of the REPORT frame, and instructs the REPORT frame generation unit 66 of the transmission timing of the REPORT frame.

  The uplink data reception unit 61 performs predetermined reception processing on the uplink data received from the terminal connected to itself (terminal 7 in the case of the ONU 6-1 in FIG. 1), and outputs it to the uplink data distribution unit 62 . The upstream data distribution unit 62 distributes each priority class and stores it in the corresponding queue buffer of the upstream queue buffer unit 63. The upstream queue buffer unit 63 includes a queue buffer for each priority class.

  The uplink buffer read control unit 64 reads the uplink data stored in the uplink queue buffer unit 63 based on an instruction from the uplink scheduler unit 67 and outputs the uplink data to the uplink data transmission unit 65. The uplink data transmission unit 65 transmits the input uplink data to the OLT 4.

  The REPORT frame generation unit 66 is a band request unit that generates and transmits a REPORT frame for requesting a band. The REPORT frame generation unit 66 monitors the amount of upstream data stored in the upstream queue buffer unit 63 and stores the upstream data amount stored in the upstream queue buffer unit 63 based on an instruction from the upstream scheduler unit 67. The generated REPORT frame is output to the upstream data transmission unit 65. The REPORT frame generation unit 66 may generate a REPORT frame including the uplink data amount and output it to the uplink data transmission unit 65 when a predetermined amount or more of data is accumulated in the uplink queue buffer unit 63. The upstream data transmission unit 65 transmits the input REPORT frame to the OLT 4.

  The downlink data multiplexer 70 multiplexes downlink data input from the downlink data receiver 71 and outputs the multiplexed data to the downlink data transmitter 69. The downlink data transmission unit 69 transmits the multiplexed data to the terminal to which it is connected. As the configuration and operation of the ONU 6 described above, the configuration and operation of the ONU corresponding to the DBA used in the conventional E-PON system may be used as they are.

  Next, the bandwidth allocation control operation of the present embodiment will be described. FIG. 5 is an operation sequence diagram illustrating an example of the bandwidth allocation operation according to the present embodiment. In FIG. 5, the ONUs 6-1 and 6-2 are connected to the PON-IF 3-2 of the OLT 4 of the present embodiment, and the terminals 7-1 and 7-2 are connected to the ONU 6-1 and the ONU 6-2, respectively. explain.

  In the L2SW 1, when the upstream buffer congestion monitoring unit 16 detects congestion of the queue buffer, as described above, the congestion queue notification control frame storing the corresponding queue type and the corresponding queue identifier is transmitted to the OLT 4 ( Step S11). In FIG. 5, it is assumed that the L2SW1 configures a queue buffer for each VLAN, and the VLAN corresponding to the VID # 2 is congested. Accordingly, in step S11, the L2SW 1 transmits a congestion queue notification control frame storing VLAN as the queue type and VID # 2 as the queue identifier.

  The OLT 4 (PON-IF 3-2 of OLT 4) grasps the congestion state of the queue buffer of the L2SW 1 based on the received congestion queue notification control frame (step S12). Specifically, in the example of FIG. 5, the congestion queue notification control frame analysis unit 37 detects that VID # 2 is congested based on the congestion queue notification control frame, and sets the LLID corresponding to VID # 2 to DBA. Notify the scheduler unit 35.

  On the other hand, when the ONU 6-1 receives the uplink data from the terminal 7-1 (step S13), the ONU 6-1 stores the received uplink data in the uplink queue buffer unit 63. Then, the ONU 6-1 stores the amount of uplink data accumulated in the queue buffer unit 63 in the REPORT frame for requesting the bandwidth and notifies the OLT 4 (step S14).

  In the OLT 4, when the REPORT frame is received, the LLID (ONU) to which the DBA scheduler unit 35 has transmitted the bandwidth request in the REPORT frame matches the LLID corresponding to the LLID corresponding to VID # 2 (referred to as LLID # 2). Determine whether or not. Here, the LLID that transmitted the bandwidth request is LLID # 1, and it is determined that LLID # 1 does not match LLID # 2 corresponding to VID # 2 (step S15).

  In the OLT 4, the DBA scheduler unit 35 grasps the uplink data amount accumulated in the ONU 6-1 based on the uplink data amount acquired from the REPORT frame analysis unit 34 (step S16), and the uplink data amount accumulated in the ONU 6-1 A band (transmission start time and transmission permission time) to be allocated to the ONU 6-1 is obtained based on the ONU use band (step S17).

  In the OLT 4, the GATE frame generation unit 36 generates a GATE frame that permits transmission in which the allocation result calculated in step S17 is stored, and the downlink data multiplexing unit 39 and the downlink data transmission unit 38 transmit it to the ONU 6-1 (step S18). ). The ONU 6-1 transmits uplink data based on the received GATE frame (step S19).

  Further, when the ONU 6-2 receives uplink data from the terminal 7-2, Steps S13 and S14 are performed in the same manner as the ONU 6-1. In the OLT 4, when the REPORT frame is received, the DBA scheduler unit 35 matches the LLID (referred to as LLID # 2) that transmitted the bandwidth request in the REPORT frame with the LLID (referred to as LLID # 2) corresponding to the VID # 2. Judgment is made (step S15a), and the GATE frame generation unit 36 generates a GATE frame without transmission permission and transmits it to the ONU 6-2 without assigning to the ONU 6-2 (step S18a).

  The operation sequence illustrated in FIG. 5 is merely an example, and transmission / reception of a congestion queue notification control frame between L2SW1 and OLT4 (step S11) and transmission / reception of REPORT frame and GATE frame between ONUs 6-1 and 6-2-OLT4. (Step S14, Step S18, Step S18a) may be mixed in time. That is, for example, the OLT 4 may receive a congestion queue notification control frame after receiving a REPORT frame. In this case, for example, when a bandwidth has already been allocated to the LLID corresponding to VID # 2 when the congestion queue notification control frame is received, a GATE frame without transmission permission is transmitted to the ONU corresponding to the LLID. do it.

  In addition, the REPORT frame for the next bandwidth request may be transmitted simultaneously with the uplink data transmission from the ONU 6-1 (step S19).

  In the present embodiment, the L2SW 2 has been described as an example of a host device that connects the PON system and the host network 2. However, the present invention is not limited to this, and the present embodiment also includes a GW device or the like as a host device. A similar bandwidth allocation method can be implemented.

  As described above, in this embodiment, the L2SW 1 is congested with the uplink buffer congestion monitoring unit 16 that monitors the uplink data stored in the uplink queue buffer unit 13 in the QoS control unit (the queue configuration unit), and the uplink data. A congestion queue control frame generation unit 17 for notifying a queue identifier. The OLT 4 performs bandwidth allocation except for the congestion queue notification control frame analysis unit 37 for obtaining the LLID corresponding to the queue notified by the congestion queue control frame and the LLID corresponding to the queue notified by the congestion queue control frame. And a DBA scheduler unit 35.

  Therefore, frame discard due to buffer overflow in L2SW1 can be reduced. Further, by mapping the QoS control unit (queue configuration unit) of the L2SW 1 and the LLID that is a unit of dynamic bandwidth allocation control in the PON system, the OLT 4 can reduce frame discard due to a difference in control unit.

  The operation related to the DBA of the ONU 6 according to the present embodiment, the format of the REPORT frame and the GATE frame are the same as those of the conventional E-PON system. The ONU 6 notifies the OLT 4 of the accumulated data amount of the own ONU using the REPORT frame, and the ONU 6 transmits uplink data according to the transmission start time and the transmission permission time notified by the OLT 4. However, the DBA algorithm executed by the OLT 4 is different from the conventional one in that the ONU (LLID) corresponding to the queue in congestion is excluded in consideration of the queue buffer congestion state notified from the L2SW 1.

Embodiment 2. FIG.
FIG. 6 is a diagram illustrating a functional configuration example of the second embodiment of the PON-IF 3a according to the present invention. The configuration of the communication system of the present embodiment is the same as that of the communication system of the first embodiment except that the OLT 4 and ONUs 6-1 to 6-n of the first embodiment are replaced with OLT 4a and ONUs 6a-1 to 6a-n, respectively. The configuration is the same. Further, the OLT 4a according to the present embodiment includes PON-IFs 3a-1 to 3a-m having the same configuration as the PON-IF 3a shown in FIG. The PON-IF 3a of the present embodiment includes a DBA scheduler unit 35, a GATE frame generation unit 36, and a congestion queue notification control frame analysis unit 37 of the PON-IF 3 of the first embodiment, respectively. , Except for the congestion queue notification control frame analysis unit 37a, is the same as the PON-IF 3 of the first embodiment. Components having the same functions as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

  In the first embodiment, the OLT 4 maps the congested queue information (queue configuration unit) notified from the L2SW 1 to the QoS control unit (LLID) used for bandwidth allocation of the PON system, and the OLT 4 The bandwidth to be allocated is calculated and dynamic bandwidth allocation control is performed.

  However, in the case of the above-described (c) described in Embodiment 1, the correspondence between the LLID and the L2SW1 buffer queue configuration unit is that a frame corresponding to one LLID is distributed to a plurality of queues in L2SW1. For this reason, even if the LLID corresponds to a congested buffer, there is a frame that does not enter the corresponding buffer. In the first embodiment, for example, when the L2SW 1 has a queue configuration (buffer configuration) according to the priority class, if the queue buffer of the priority class # 1 is congested, all the LLIDs corresponding to the congested queue are stored in the OLT 4 Is excluded from allocation targets, transmission is stopped up to frames other than the priority class # 1 of the LLID. Therefore, in the present embodiment, the congestion queue notification control frame analysis unit includes not only the OLT but also the ONU to prevent the unnecessary transmission stop as described above.

  The configuration of L2SW1 in the present embodiment is the same as that in the first embodiment. Returning to FIG. 6, the operation of the PON-IF 3a will be described. As in the first embodiment, the operation of the downlink data reception unit 40 extracts a congestion queue notification control frame from the downlink data received from the L1SW 2 and outputs it to the congestion queue notification control frame analysis unit 37a. ) To the downlink data multiplexing unit 39.

  The congestion queue notification control frame analysis unit 37a generates queue information (queue type and queue identifier) during congestion of L2SW1 stored in the congestion queue notification control frame input from the downlink data reception unit 40 to generate an uplink GATE frame. Notification to the unit 36a. In the first embodiment, the congestion queue notification control frame analysis unit 37 performs mapping to LLID based on the queue information during congestion of the L2SW1, but in this embodiment, mapping to LLID is not performed. The GATE frame generation unit 36 a generates a GATE frame storing the notified queue information during congestion of the L2SW 1 and outputs the GATE frame to the downlink data multiplexing unit 39.

  The DBA schedule unit 35a obtains a band to be allocated (transmission start time and transmission permission time) based on the upstream data amount of each ONU notified from the REPORT frame analysis unit 34 as in the conventional technique, and sends it to the GATE frame generator 36a. Notice. The GATE frame generation unit 36a generates a GATE frame storing the allocation result. At this time, for example, during congestion (or congestion) of the L2SW1 notified from the congestion queue notification control frame analysis unit 37a in the Reserve area (unused area), for example. (Release) queue information is stored.

  The operations of the downlink data multiplexing unit 39 and the downlink data transmission unit 38 are the same as those in the first embodiment. The operations of the uplink data receiving unit 31, the uplink data allocating unit 32, the uplink data transmitting unit 33, and the REPORT frame analyzing unit 34 are the same as those in the first embodiment.

  The PON-IF 3a may use a dedicated control frame (congestion queue notification control frame) as a method for notifying the ONU of the queue information during congestion of the L2SW 1, but as described above, in the Reserve area of the GATE frame. By transmitting the information including the congestion queue information of L2SW1, it is possible to reduce the increase in the bandwidth for control. When transmitting with a dedicated control frame, the means for generating and transmitting the control frame functions as a congestion information notification means for notifying the queue information during congestion. When notifying queue information during congestion of the L2SW 1 using a GATE frame, the GATE frame generation unit 36a also has a function as a congestion information notification unit.

  FIG. 7 is a diagram illustrating a functional configuration example of the ONU 6a according to the present embodiment. The ONUs 6a-1 to 6a-n configuring the communication system of the present embodiment have the same configuration, and in FIG. 7, these are representatively described as ONUs 6a. The ONU 6a of the present embodiment is the same as the ONU 6 of the first embodiment except that a congestion queue notification control frame analysis unit 72 is added to the ONU 6 of the first embodiment and an upstream scheduler 67a is provided instead of the upstream scheduler 67. .

  The downlink data receiving unit 71 extracts the GATE frame as in the first embodiment, but outputs the extracted GATE frame to the GATE frame analyzing unit 68. Based on the GATE frame, the GATE frame analysis unit 68 extracts the transmission start time and transmission permission time given to the GATE frame analysis unit 68 and outputs the transmission start time and the transmission permission time to the uplink scheduler unit 67a, and also during the congestion of the L2SW1 described in the Reserve area The queue information is extracted and output to the uplink scheduler 67a. When the congestion release is notified by the GATE frame, the information on the congestion release target queue is output to the uplink scheduler 67a together with the information indicating the congestion release.

  In FIG. 7, the congestion queue notification control frame analysis unit 72 is configured assuming that the information on the queue during congestion of the L2SW1 is transmitted by an independent congestion queue notification control frame instead of the GATE frame. In this case, when receiving the congestion queue notification control frame, the downlink data receiving unit 71 notifies the congestion queue notification control frame analysis unit 72 of the frame, and the congestion queue notification control frame analysis unit 72 notifies the congestion queue notification control frame. Information of the queue during congestion of L2SW1 is extracted from the information and output to the uplink scheduler 67a. Note that in the case where the queue information during congestion of the L2SW 1 is stored in the GATE frame, the GATE frame analysis unit 68 has the function of the congestion queue notification control frame analysis unit 72, and the congestion queue notification control frame analysis unit 72. Need not be provided separately.

  Uplink scheduler section 67a schedules transmission of uplink data based on the transmission start time and transmission permission time input from GATE frame analysis section 68, and information on queues during congestion of L2SW1, and an uplink buffer read control section 64 to instruct the reading of the uplink data to be transmitted. Specifically, scheduling is performed so as to transmit uplink data excluding data corresponding to information on queues during congestion of L2SW1 based on the transmission start time and the transmission permission time. In the case of congestion release, scheduling is performed so that uplink data including data corresponding to the notified queue information is transmitted.

  Here, it is assumed that the queue configuration of L2SW1 and the queue configuration of ONU 6a correspond to each other. Further, the upstream data distribution unit 62 and the upstream scheduler unit 67a grasp the data distribution direction (identification method) corresponding to the queue configuration of the L2SW1, and the L2SW1 is transmitted to the upstream buffer read control unit 64. It is instructed to read only frames that do not fall into the queue during congestion. For example, when the L2SW1 has a VLAN configuration queue unit, the uplink scheduler 67a grasps the correspondence between the LLID and the VID, and corresponds to the VID # 2 when the VID # 2 is congested. Uplink data is transmitted for frames other than LLID. In the REPORT frame, the OLT 4a is notified of the amount of accumulated data for data not corresponding to VID # 2. For example, when the queue configuration of the L2SW 1 is based on the priority class, the queue configuration of the ONU 6a is also configured based on the priority class.

  Further, the upstream scheduler unit 67a notifies the REPORT frame generation unit 66 of the queue information during congestion of the L2SW1, and the REPORT frame generation unit 66 excludes the data corresponding to the information of the queue during congestion of the L2SW1 and stores the upstream accumulated data. The amount is obtained, and a REPORT frame storing the obtained amount of uplink accumulated data is generated.

  Next, the bandwidth allocation control operation of the present embodiment will be described. FIG. 8 is an operation sequence diagram illustrating an example of the bandwidth allocation operation according to the present embodiment. In FIG. 8, the ONUs 6a-1 and 6a-2 are connected to the PON-IF 3a-2 of the OLT 4a of the present embodiment, and the terminals 7-1 and 7-2 are connected to the ONU 6a-1 and the ONU 6a-2, respectively. explain.

  When detecting the congestion of the queue buffer (or detecting the congestion release), the L2SW 1 transmits a congestion queue notification control frame storing the type of the corresponding queue and the identifier of the corresponding queue to the OLT 4a (step S21). Here, it is assumed that the L2SW1 configures a queue for each priority class, and that congestion of the queue buffer corresponding to the priority class # 1 is detected.

  In the OLT 4a (PON-IF 3a-2), it is stored in the congestion queue notification control frame or in the GATE frame, and the ONU 6a indicates that the queue information during congestion of the L2SW 1 (in this case, the priority class # 1 is congested). -1, 6a-2 is notified (step S22).

  On the other hand, the ONU 6a-1 receives uplink data from the terminal 7-1 (step S23). The ONU 6a-1 recognizes that the priority class # 1 is congested by the notification in step S22, and determines the amount of uplink stored data excluding the frame corresponding to the priority class # 1 as a REPORT frame for bandwidth request. And transmitted to the OLT 4a (step S24).

  The OLT 4a grasps the upstream accumulated data amount of the ONU 6a-1 based on the REPORT frame (step S25), and allocates a band to the ONU 6a-1 based on the upstream accumulated data amount (step S26). Then, the allocation result is stored in the GATE frame notifying the transmission permission and transmitted to the ONU 6a-1 (step S27). The ONU 6a-1 transmits the uplink accumulated data excluding the frame of the priority class # 1 based on the allocation result stored in the GATE frame (step S28).

  In FIG. 8, the transmission / reception of the congestion queue notification control frame between the L2SW 1 and the OLT 4a and the transmission / reception of the REPORT frame and the GATE frame between the ONUs 6-1 and 6-2-OLT 4a may be mixed in time. Further, uplink data is transmitted between the terminal 7-2-ONU 6a-2 as well as between the terminal 7-1 and ONU 6a-1, but the operation for the uplink data is omitted in FIG. In addition, the REPORT frame for the next bandwidth request may be transmitted simultaneously with the uplink data transmission from the ONUs 6a-1 and 6a-2.

  Hereinafter, as another example of the present embodiment, an example of a queue configuration (buffer configuration) in units of destinations (services) will be described. Specifically, for example, when a SIP (Session Initiation Protocol) server is connected to the PON system of the present embodiment in VoIP and connected to an ISP (Internet Services Provider: Internet access) as the higher level network 2, the destination An example in which can be identified will be described.

  First, the L2SW 1 notifies the OLT 4a of an identifier of a destination (service) that is congested with a congestion queue notification control frame. The OLT 4a notifies the ONUs 6a-1 and 6a-2 of the congestion destination using a dedicated frame (congestion queue notification control frame) or a GATE frame.

  The ONUs 6a-1 and 6a-2 store the uplink accumulated data amount other than the destination being congested in the L2SW1 in the REPORT frame, and execute the bandwidth request. The OLT 4a calculates a band to be allocated to each ONU based on the uplink accumulated data amount notified from each ONU, and notifies each ONU of the allocation result (transmission start time and transmission permission time) with a GATE frame. The ONU performs uplink data transmission for data other than the destination that is congested in the L2SW 1 based on the GATE frame.

  As described above, in the present embodiment, the OLT 4a notifies the ONU 6a of the queue that is congested by the L2SW1, and the ONU 6a stores the uplink accumulated data amount excluding the queue that is congested by the L2SW1 in the REPORT frame and sends it to the OLT 4a. Added notification. Then, the OLT 4a performs bandwidth allocation based on the uplink accumulated data amount notified from each ONU as in the conventional case, and the ONU 6a transmits the uplink accumulated data excluding the queue that is congested by the L2SW1 based on the allocation result. I did it.

  Therefore, frame discard due to buffer overflow in L2SW1 can be reduced. Further, since the ONU 6a reports the uplink accumulated data amount by excluding frames corresponding to the congestion queue of the L2SW1, the DBA algorithm executed by the OLT 4a may be the same as the conventional one, and the existing processing as the DBA scheduler unit 35a. Part can be used.

Embodiment 3 FIG.
FIG. 9 is a diagram illustrating a configuration example of the third embodiment of the communication system according to the present invention. The communication system according to the present embodiment is the same as the communication system according to the first embodiment except that the integrated device 8 is provided instead of the L2SW1 and the OLT 4 in the communication system according to the first embodiment. Components having the same functions as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

  The integrated device 8 of the present embodiment is a device in which the functions of the L2SW 1 and the OLT 4 of the first embodiment are integrated. The integrated device 8 includes an L2SW 1b that is an L2SW function unit having the same configuration as the L2SW 1 of the first embodiment, and an OLT 4b that is an OLT function unit having the same configuration as the OLT 4 of the first embodiment. . The operation of the present embodiment is the same as that of the first embodiment except that the signal between the L2SW 1b and the OLT 4b becomes an in-device wiring signal.

  In this embodiment, the OLT 4b has the same configuration as the OLT 4 of the first embodiment. However, the present invention is not limited to this, and the OLT 4b has the same configuration as the OLT 4a of the second embodiment. Instead of -n in the ONUs 6a-1 to 6a-n in the second embodiment, the same operation as in the second embodiment may be performed.

  As described above, when the integrated device 8 is provided, it is necessary to use the control frame (congestion queue notification control frame) as in the first embodiment when notifying the queue information during congestion from the L2SW 1b to the OLT 4b. Instead, an in-device wiring signal may be used. In this case, since transmission of the control frame is not required, when the line between the L2SW 1b and the OLT 4b is not a dedicated line, the band of the line is not consumed and the band can be used effectively. Furthermore, since it is an in-device wiring signal, notification can be made faster than when a control frame is transmitted.

  As described above, the communication system and the bandwidth allocation control method according to the present invention are useful for a communication system including a PON system and a host device that connects the PON system and a host network. In particular, the host device has a buffer for each queue. Suitable for the communication system provided.

1,1b L2SW
2 Upper network 3-1 to 3-m, 3a-1 to 3a-m PON-IF
4,4a, 4b OLT
5 couplers 6-1 to 6-n, 6a-1 to 6a-n ONU
7, 7-1, 7-2 Terminal 8 Integrated device 11, 31, 61 Up data receiver 12, 32, 62 Up data distribution unit 13, 63 Up queue buffer unit 14, 64 Up buffer read control unit 15, 33, 65 Uplink data transmission unit 16 Upstream buffer congestion monitoring unit 17 Congestion queue notification control frame generation unit 18, 38, 69 Downlink data transmission unit 19, 39, 70 Downlink data multiplexing unit 20, 40, 71 Downlink data reception unit 34 REPORT Frame analysis unit 35, 35a DBA scheduler unit 36, 36a GATE frame generation unit 37, 37a, 72 Congestion queue notification control frame analysis unit 66 REPORT frame generation unit 67, 67a Uplink scheduler unit 68 GATE frame analysis unit

Claims (14)

A communication system comprising: a PON system composed of a station-side terminal device and a subscriber-side terminal device; and a host device that relays communication data between the PON system and a host network and performs QoS control. ,
The host device is
Upstream queue buffer means comprising a queue buffer for storing each upstream data as the communication data transmitted from the PON system to the upper network, for each QoS control unit;
An upstream data distribution unit that distributes the communication data received from the PON system for each QoS control unit and stores the communication data in the corresponding queue buffer of the upstream queue buffer unit;
Congestion monitoring means for monitoring congestion for each queue buffer and notifying an identifier of a queue corresponding to the queue buffer in which congestion has occurred;
Control frame generating means for generating a control frame including the identifier notified by the uplink buffer congestion monitoring means and transmitting the control frame to the station-side terminal device;
With
The station side termination device is:
Control frame analysis means for extracting the identifier from the control frame and obtaining a logical link identifier corresponding to the identifier as an allocation exclusion logical identifier ;
Bandwidth allocation means for performing bandwidth allocation processing based on the allocation exclusion logical identifier for the subscriber-side termination device;
Equipped with a,
The communication data transmitted from a plurality of the terminal devices on the subscriber side is stored in one queue buffer,
A plurality of the allocation exclusion logical identifiers corresponding to one of the identifiers,
A communication system characterized by the above. A communication system comprising: a PON system composed of a station-side terminal device and a subscriber-side terminal device; and a host device that relays communication data between the PON system and a host network and performs QoS control. ,
The host device is
Upstream queue buffer means comprising a queue buffer for storing each upstream data as the communication data transmitted from the PON system to the upper network, for each QoS control unit;
An upstream data distribution unit that distributes the communication data received from the PON system for each QoS control unit and stores the communication data in the corresponding queue buffer of the upstream queue buffer unit;
Congestion monitoring means for monitoring congestion for each queue buffer and notifying an identifier of a queue corresponding to the queue buffer in which congestion has occurred;
Control frame generating means for generating a control frame including the identifier notified by the uplink buffer congestion monitoring means and transmitting the control frame to the station-side terminal device;
With
The station side termination device is:
Control frame analysis means for extracting the identifier from the control frame and obtaining a logical link identifier corresponding to the identifier as an allocation exclusion logical identifier;
Bandwidth allocation means for performing bandwidth allocation processing based on the allocation exclusion logical identifier for the subscriber-side termination device;
With
The communication data transmitted from one subscriber-side terminal device is stored in a plurality of the queue buffers,
One or more of the allocation exclusion logical identifiers corresponding to one of the identifiers,
Communication system that is characterized in that. Before Symbol band allocation unit, a bandwidth allocation process based on the identifier, performing the bandwidth allocation process that excludes the subscriber side terminating device corresponding to the assigned excluded logical identifier from the assignment target,
The communication system according to claim 1 or 2 . The uplink buffer congestion monitoring means, when congestion of the queue buffer that has caused congestion has been resolved, notifies that the congestion has been resolved together with the identifier of the queue corresponding to the queue buffer,
The control frame generation unit generates a control frame including the notified identifier and information indicating congestion cancellation when receiving notification that the congestion is eliminated from the uplink buffer congestion monitoring unit. To the end device,
In the station side termination device,
When the control frame analysis unit extracts the identifier and information indicating congestion elimination from the control frame, the control frame analysis unit excludes the logical link identifier corresponding to the identifier from the allocation exclusion logical identifier.
The communication system according to claim 3 . A communication system comprising: a PON system composed of a station-side terminal device and a subscriber-side terminal device; and a host device that relays communication data between the PON system and a host network and performs QoS control. ,
The host device is
Upstream queue buffer means comprising a queue buffer for storing each upstream data as the communication data transmitted from the PON system to the upper network, for each QoS control unit;
An upstream data distribution unit that distributes the communication data received from the PON system for each QoS control unit and stores the communication data in the corresponding queue buffer of the upstream queue buffer unit;
Congestion monitoring means for monitoring congestion for each queue buffer and notifying an identifier of a queue corresponding to the queue buffer in which congestion has occurred;
Control frame generating means for generating a control frame including the identifier notified by the uplink buffer congestion monitoring means and transmitting the control frame to the station-side terminal device;
With
The station side termination device is:
Control frame analysis means for extracting the identifier from the control frame;
Bandwidth allocation means for performing bandwidth allocation processing based on the identifier for the subscriber-side termination device;
And congestion information notifying means for notifying the identifier and the control frame analysis means has extracted to the subscriber side terminating device,
With
The subscriber-side termination device is:
Congestion information extraction means for extracting the identifier transmitted from the congestion information notification means;
Bandwidth for transmitting to the station-side terminal device a bandwidth request in which the amount of data excluding the transmission data corresponding to the identifier is stored as a data amount for requesting transmission among the amount of transmission data transmitted from the own device to the upper network Request means;
An uplink scheduler for controlling transmission of data excluding transmission data corresponding to the identifier from transmission data transmitted from the own device to the upper network, to the station-side terminal device;
With
The band allocating unit performs a band allocation process based on the amount of data included in the received band request as a band allocation process based on the identifier.
Communication system that is characterized in that. The uplink buffer congestion monitoring means, when congestion of the queue buffer that has caused congestion has been resolved, notifies that the congestion has been resolved together with the identifier of the queue corresponding to the queue buffer,
The control frame generation unit generates a control frame including the notified identifier and information indicating congestion cancellation when receiving notification that the congestion is eliminated from the uplink buffer congestion monitoring unit. To the end device,
In the station side termination device,
When the control frame analysis unit extracts the identifier and information indicating congestion elimination from the control frame, the extracted identifier is used as a congestion elimination identifier,
The congestion information notification means notifies the congestion elimination identifier to the subscriber-side terminating device,
The congestion information extraction unit extracts the congestion resolution identifier from the notification transmitted from the congestion information notification unit,
The bandwidth request means includes transmission data corresponding to the congestion resolution identifier in a data amount for requesting transmission,
The uplink scheduler controls transmission data corresponding to the congestion elimination identifier to be transmitted to the station-side terminal device.
The communication system according to claim 5 . The queue buffer and the terminal device on the subscriber side have a one-to-one correspondence.
The subscriber side termination device performs the operations of the congestion information extraction unit, the bandwidth request unit, and the uplink scheduler for one identifier.
The communication system according to claim 5 or 6 . The communication data transmitted from a plurality of the terminal devices on the subscriber side is stored in one queue buffer,
The plurality of subscriber-side termination devices perform the operations of the congestion information extraction unit, the bandwidth request unit, and the uplink scheduler for one identifier.
The communication system according to claim 5 or 6 . The communication data transmitted from one subscriber-side terminal device is stored in a plurality of the queue buffers,
The one or more subscriber-side termination devices perform the operations of the congestion information extraction unit, the bandwidth request unit, and the uplink scheduler for one identifier.
The communication system according to claim 5 or 6 . The QoS control unit is a priority class,
The identifier is an identifier representing a priority class;
The communication system according to claim 1, 2 , 8, or 9 . The QoS control unit is VLAN,
The identifier is VID.
The communication system according to any one of claims 1, 2 , 7 to 9 . The QoS control unit is the destination,
The identifier is a service type identifier.
The communication system according to claim 1, 2 , 8, or 9 . The host device and the station-side terminal device are mounted in one integrated device.
Communication system according to any one of claims 1 1 2, characterized in that. Bandwidth allocation in a communication system comprising: a PON system composed of a station-side terminal device and a subscriber-side terminal device; and a host device that relays communication data between the PON system and a host network and performs QoS control A control method,
The host device includes a queue buffer for storing uplink data that is the communication data transmitted from the PON system to the host network for each QoS control unit,
An upstream data distribution step in which the host device stores the communication data received from the PON system in the queue buffer corresponding to the distribution for each QoS control unit;
The host device monitors congestion for each queue buffer, and notifies an identifier of a queue corresponding to the queue buffer in which congestion has occurred, an upstream buffer congestion monitoring step;
A control frame generating step in which the upper device generates and transmits a control frame including the identifier notified in the uplink buffer congestion monitoring step;
A control frame analyzing step in which the station-side terminal device extracts the identifier from the control frame and obtains a logical link identifier corresponding to the identifier as an allocation exclusion logical identifier ;
A bandwidth allocation step in which the station side termination device performs bandwidth allocation processing based on the allocation exclusion logical identifier for the subscriber side termination device;
Only including,
The communication data transmitted from a plurality of the terminal devices on the subscriber side is stored in one queue buffer,
A plurality of the allocation exclusion logical identifiers corresponding to one of the identifiers,
A bandwidth allocation control method characterized by the above.

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