WO2022269853A1

WO2022269853A1 - Bandwidth allocation device, subscriber line termination device, and bandwidth allocation method

Info

Publication number: WO2022269853A1
Application number: PCT/JP2021/023944
Authority: WO
Inventors: 亮太喜多; 真良関口; 智暁吉田; 聡志嶌津; 隆義田代
Original assignee: 日本電信電話株式会社
Priority date: 2021-06-24
Filing date: 2021-06-24
Publication date: 2022-12-29
Also published as: JPWO2022269853A1

Abstract

According to the present invention, a bandwidth allocation device comprises a detection unit and a setting unit. The detection unit detects connection to a passive optical network by a subscriber line terminal device that does not have a transmission reservation queue for making uplink data that has been cleared to be transmitted stand by until a transmission start time. The setting unit sets a calculation time for the subscriber line terminal device within an operation period for uplink bandwidth control between the subscriber line terminal device and a subscriber line termination device, the calculation time being the time needed for calculation of the amount of uplink data that is to be transmitted of the amount of uplink data that has been cleared to be transmitted and calculation of the amount of uplink data that is to be requested to be transmitted.

Description

Bandwidth allocation device, subscriber line terminal device, and band allocation method

The present invention relates to a band allocation device, a subscriber line terminal device, and a band allocation method.

FTTH (Fiber To The Home) is spreading worldwide in response to the growing need for faster access services. Mainstay FTTH services in Japan include, for example, GE-PON (Gigabit Ethernet PON) and 10G-EPON (10 Gigabit Ethernet PON), which realize gigabit-class transmission speeds.

In GE-PON and 10G-EPON, TDMA (Time Division Multiple Access) technology is used in upstream communication from ONUs to OLTs. Also, one of the functions required to operate GE-PON and 10G-EPON as a system is a DBA (Dynamic Bandwidth Allocation) function. The DBA function is a bandwidth control function that dynamically allocates bandwidth in upstream communication according to traffic volume. The DBA function realizes efficient upstream bandwidth without generating unused bandwidth by appropriately switching the allocated bandwidth according to the status of upstream communication traffic flowing through each ONU.

JP-A-2003-087283

In the DBA function, the OLT indicates the transmission start time and transmission amount of uplink data using a GATE frame so that each ONU can transmit uplink data without time collision. On the other hand, each ONU notifies the OLT of the amount of uplink data waiting for transmission stored in its own ONU buffer by means of a REPORT frame. The DBA function is realized by exchanging data using the GATE frame and the REPORT frame.

In upstream communication, when the interval from data transmission to the REPORT frame transmission start time is short, the ONU waits for the transmission permitted upstream data until the transmission start time. It is necessary to calculate the amount of data. However, there may be ONUs that do not have transmission reservation queues. ONUs that do not have a reserved transmission queue calculate the amount of data reserved for transmission permitted by the OLT, and the remaining amount of accumulated data after excluding the reserved data amount The amount of data (that is, the amount of uplink data waiting for a transmission request) is calculated.

However, in an ONU that does not have a transmission reservation queue, it is necessary to sequentially process data transmission and the above two calculations (that is, calculation of the amount of data reserved for transmission and calculation of the amount of data waiting for a transmission request). Therefore, it takes time to complete the calculation, and there is a possibility that the calculation will not be completed before the transmission start time of the REPORT frame. In this case, since the ONU does not send a REPORT frame, the OLT cannot give permission to send uplink data. As a result, there is a problem that the ONU may not be able to transmit uplink data.

In view of the above circumstances, the present invention provides a bandwidth allocation device, a subscriber line terminal device, and a subscriber line terminal device capable of enabling transmission of uplink data even if ONUs having no transmission reservation queue are included in a PON system. An object of the present invention is to provide a bandwidth allocation method.

According to one aspect of the present invention, a detection unit that detects that a subscriber line terminating device that does not have a transmission reservation queue for waiting uplink data permitted to be transmitted until a transmission start time is connected to a passive optical network; , during an operation period of upstream band control between the subscriber line terminating equipment and the subscriber line terminal equipment, the amount of uplink data permitted to be transmitted in the subscriber line terminating equipment is transmitted; A bandwidth allocation device comprising: a setting unit that provides a calculation time that is a time required for calculation of the data amount of data and calculation of the data amount of uplink data to be requested for transmission.

According to one aspect of the present invention, an acquisition unit acquires identification information identifying a subscriber line terminating device connected to a passive optical network; a judgment unit for judging whether or not a transmission reservation queue for waiting data transmission start time is provided; and a setting change unit that provides a predetermined calculation time between operation cycles of upstream bandwidth control.

According to one aspect of the present invention, a detection unit that detects that a subscriber line terminating device that does not have a transmission reservation queue for waiting uplink data permitted to be transmitted until a transmission start time is connected to a passive optical network; , an amount of uplink data to be transmitted out of the amount of uplink data permitted to be transmitted in said subscriber line terminating apparatus during an operation cycle of uplink band control between said subscriber line terminating apparatus and its own apparatus; and the amount of uplink data to be requested for transmission; subscriber line terminal equipment.

According to one aspect of the present invention, an acquisition unit acquires identification information identifying a subscriber line terminating device connected to a passive optical network; a judgment unit for judging whether or not a transmission reservation queue for waiting data transmission start time is provided; The subscriber line terminal equipment includes a setting changing unit that provides a predetermined calculation time between operation cycles of upstream band control, and a transmitting/receiving unit that transmits/receives data to/from the subscriber line terminating equipment.

An aspect of the present invention is a detection step of detecting that a subscriber line terminating equipment that does not have a transmission reservation queue for waiting uplink data permitted to be transmitted until a transmission start time is connected to the passive optical network; , during an operation period of upstream band control between the subscriber line terminating equipment and the subscriber line terminal equipment, the amount of uplink data permitted to be transmitted in the subscriber line terminating equipment is transmitted; A bandwidth allocation method comprising a setting step of setting a calculation time, which is the time required for calculating the data amount of data and calculating the data amount of uplink data to be requested for transmission.

According to one aspect of the present invention, an acquiring step of acquiring identification information that identifies a subscriber line terminating device connected to a passive optical network; a determination step of determining whether or not a transmission reservation queue for waiting data to be transmitted until a transmission start time is provided; and a setting change step of providing a predetermined calculation time between operation cycles of upstream bandwidth control.

According to the present invention, even if an ONU that does not have a transmission reservation queue is included in the PON system, it is possible to transmit upstream data and improve the efficiency of using the band.

1 is a block diagram showing the configuration of a general PON; FIG. FIG. 4 is a diagram showing the flow of transmission of uplink data when there is only one ONU 20; FIG. 4 is a diagram showing the flow of transmission of uplink data when there are two ONUs 20; FIG. 4 is a schematic diagram for explaining changes in the amount of accumulated uplink data; FIG. 4 is a schematic diagram showing an example of the configuration of a granted queue; It is a figure which shows the flow of transmission of uplink data by PON1 in embodiment of this invention. FIG. 2 is a diagram showing a flow of transmission of uplink data by a conventional PON; 3 is a block diagram showing the functional configuration of OLT 10 in the embodiment of the present invention; FIG. 3 is a diagram showing an example of the configuration of a pre-report GAP database 105. FIG. 4 is a flow chart showing the operation of OLT 1 in the embodiment of the present invention;

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

PON (Passive Optical Network) is an optical access system that provides FTTH services at high speed and at low cost. A PON does not perform optical-to-electrical conversion, but uses low-cost passive optical splitters to split an optical signal into multiple parts. As a result, the PON can realize an economical network by sharing one optical fiber with a plurality of users. Mainstay FTTH services in Japan include, for example, GE-PON, which achieves gigabit-class transmission speeds, and 10G-EPON, which has ten times the bandwidth of GE-PON.

FIG. 1 is a block diagram showing the configuration of a general PON. As shown in FIG. 1, the PON 1 includes an OLT (Optical Line Terminal) 10 and a plurality of (n in FIG. 1) ONUs (Optical Network Units). 20 , an optical fiber 30 and an optical splitter 40 .

The OLT 10 is installed in the communication carrier's office, and the ONU 20 is installed in the user's home or premises. The optical fiber 30 is laid between the office of the telecommunications carrier and the home or premises of the user, and the optical splitter 40 branches the optical fiber 30 . A plurality of ONUs 20 are connected to one OLT 10 by installing an optical splitter 40 that multiplexes and demultiplexes optical signals between the OLT 10 and the ONUs 20 .

The ONU 20 converts an optical signal from the OLT 10 into an electrical signal, and converts an electrical signal from a user's terminal device (for example, a PC, etc.) into an optical signal and transfers the optical signal to the OLT 10 . The OLT 10 plays a role of transferring an optical signal from the ONU 20 to a host device/network (for example, the Internet), transferring a signal from the host device/network to the ONU 20, and controlling and monitoring the PON section and the ONU 20.

In the PON 1, TDM (Time Division Multiplexing) technology is used in communication from the OLT 10 to the ONU 20 (hereinafter referred to as "downlink communication"). TDM is a technique for multiplexing and transmitting signals of a plurality of users so that they do not overlap in time.

In downstream communication, the same signal (hereinafter referred to as "downstream signal") is split by the optical splitter 40 and transferred to all ONUs 20 connected to the same OLT 10 . Therefore, each ONU 20 is also transferred with data other than the data addressed to its own ONU 20 . Therefore, each ONU 20 extracts only the data addressed to its own ONU 20 from the transferred data, and discards the other data (addressed to other ONUs 20).

Also, in the PON 1, TDMA technology is used in communication from the ONU 20 to the OLT 10 (hereinafter referred to as "uplink communication"). In upstream communication, signals from a plurality of ONUs 20 (hereinafter referred to as “upstream signals”) are multiplexed by the optical splitter 40 . Therefore, if the upstream signals from the ONUs 20 are randomly transmitted, there is a possibility that they will collide on the transmission path. Therefore, TDMA controls the transmission timing of upstream signals from the ONUs 20 and the transmission amount of upstream data so that the upstream signals from each ONU 20 are multiplexed without colliding on the transmission line.

A DBA function is one of the functions required to operate GE-PON and 10G-EPON as a system. The DBA function is a bandwidth control function that dynamically allocates bandwidth in upstream communication (hereinafter referred to as "upstream bandwidth") according to traffic volume. The DBA function can flexibly allocate an upstream bandwidth according to the traffic of upstream communication from each ONU 20 (hereinafter referred to as "upstream traffic"). Since the DBA function allocates the upstream bandwidth only to the ONUs 20 in which upstream traffic is flowing, the upstream bandwidth can be used without waste. The DBA function appropriately switches the bandwidth to be allocated according to the status of upstream traffic flowing through each ONU 20, thereby realizing efficient upstream bandwidth without generating unused bandwidth.

　GE-PON and 10G-EPON implement upstream signal control using a protocol called MPCP (Multi Point Control Protocol). The OLT 10 instructs each ONU 20 of the transmission start time and transmission amount using the GATE frame so that each ONU 20 can transmit upstream signals without time collision.

On the other hand, each ONU 20 notifies the OLT 10 of the amount of uplink data waiting for transmission accumulated in the buffer of its own ONU 20 by means of a REPORT frame. The DBA function is realized by using the GATE frame and the REPORT frame.

The mechanism of the DBA function will be briefly explained below. When the ONU 20 receives the upstream data, it stores the upstream data in the buffer for the time being. The ONU 20 writes the amount of accumulated upstream data in a REPORT frame and transmits the REPORT frame to the OLT 10 .

The OLT 10 grasps the amount of upstream data accumulated in the ONU 20 from the received REPORT frame. The OLT 10 calculates the upstream bandwidth to be allocated to the ONU 20 based on the accumulated data amount of the ONU 20 and the usage bandwidth of the other ONUs 20 . Specifically, the OLT 10 calculates the transmission start time and transmission amount of the upstream data of the ONU 20 . The OLT 10 writes the calculated value in the GATE frame and transmits the GATE frame to the ONU 20 .

The ONU 20 transmits upstream data at the designated transmission time according to the instructions written in the received GATE frame. At this time, the ONU 20 may notify the amount of uplink data accumulated in the buffer again for the next uplink bandwidth allocation.

By repeating the above procedure, the OLT 10 can know the status of upstream traffic in each ONU 20, and can appropriately allocate an upstream bandwidth according to the status.

In such uplink communication, if the interval from the transmission of uplink data to the start time of REPORT frame transmission is short, it is desirable that the ONU 20 be provided with a transmission reservation queue (hereinafter referred to as "granted queue"). For example, in this case, the ONU 20 can concurrently calculate the amount of data to be described in the REPORT frame (hereinafter referred to as "report calculation") during data transmission of the granted queue.

However, there may be ONUs 20 that do not have a granted queue. For example, the PON 1 may accommodate both ONUs 20 with a granted queue and ONUs 20 without a granted queue.

The ONU 20 that does not have a granted queue calculates the amount of uplink data reserved for transmission (granted) based on the DATA grant of the GATE frame transmitted from the OLT 10 in a normal queue (for example, a priority queue), and Calculation (report calculation) of the remaining uplink data amount (that is, uplink data amount waiting for a transmission request) excluding the reserved uplink data amount (granted) is performed. Data grant indicates the amount of uplink data permitted to be transmitted by the OLT 10 .

However, in an ONU 20 that does not have a granted queue, it takes time to complete the above-mentioned REPORT calculations and the like due to sequential processing, and there is a possibility that the REPORT calculations will not be completed in time for the REPORT frame transmission start time. Here, the sequential processing means sequentially processing data transmission, calculation of the amount of data reserved for transmission, and calculation of the amount of data waiting for a transmission request. In this case, the ONU 20 cannot inform the OLT 10 of the amount of upstream data accumulated. As a result, the OLT 10 cannot give permission to transmit uplink data to the ONU 20, so the ONU 20 may not be able to transmit uplink data.

The OLT 10 in this embodiment described below secures the time required for the ONU 20 to calculate the reserved transmission of DATA grant and the amount of uplink data waiting for a transmission request between the operation cycles of upstream band control. A vacant time (hereinafter referred to as "pre-REPORT GAP") is provided. As a result, the OLT 10 in this embodiment can complete these calculations before the transmission start time of the REPORT frame.

By providing the pre-REPORT GAP in this way, even an ONU 20 that does not have a granted queue can complete REPORT calculations and the like in time for the transmission timing of the REPORT frame. Therefore, upstream communication becomes possible. Further, according to the OLT 10 of the present embodiment, upstream communication is possible even if the ONU 20 with a granted queue and the ONU 20 without a granted queue coexist.

The following describes the flow of transmission of uplink data. In order to make the explanation easier to understand, first, a case where there is only one ONU 20 will be explained. FIG. 2 is a diagram showing the flow of transmission of uplink data when there is only one ONU 20. In FIG.

The OLT 10 transmits a GATE frame g1 as shown in FIG. 2 to the ONU 20, for example. A GATE frame g1 includes a Report block and a Data block.

As shown in FIG. 2, for example, the Report block of the GATE frame g1 describes "Grant length: ▲ ₁ TQ". This means that the OLT 10 instructs the ONU 20 to allow time for transmission of the REPORT frame to be ₁ TQ. The ONU 20 transmits the REPORT frame to the OLT 10 during the transmission permission time .tangle _- solidup.1TQ according to the instruction written in the GATE frame g1.

Also, as shown in FIG. 2, for example, "Grant length: 0 ₁ TQ" is described in the Data block of the GATE frame g1. This means that the OLT 10 instructs the ONU 20 to allow 0 ₁ TQ as the transmission permission time for DATA (uplink data). The ONU 20 transmits DATA (uplink data) to the OLT 10 during the transmission permission time 0 ₁ TQ according to the instruction written in the GATE frame g1.

Next, the OLT 10 transmits the GATE frame g2 to the ONU 20 while DATA (up data) is being transmitted from the ONU 20 to the OLT 10 based on the instruction of the GATE frame g1, as shown in FIG. 2, for example. The GATE frame g2 also includes a Report block and a Data block.

As shown in FIG. 2, for example, the Report block of the GATE frame g2 describes "Grant length: ₂ TQ". This means that the OLT 10 instructs the ONU 20 to allow the transmission of the REPORT frame by ₂ TQ. The ONU 20 transmits the REPORT frame to the OLT 10 during the transmission permission time .tangle _- solidup.2TQ according to the instruction written in the GATE frame g2.

Also, as shown in FIG. 2, for example, "Grant length: 0 ₂ TQ" is described in the Data block of the GATE frame g2. This means that the OLT 10 instructs the ONU 20 to allow the transmission of DATA (uplink data) for 0 ₂ TQ. The ONU 20 transmits DATA (uplink data) to the OLT 10 during the transmission permission time 0 ₂ TQ according to the instruction written in the GATE frame g2.

Next, the flow of upstream data transmission when there are two ONUs 20 will be described. FIG. 3 is a diagram showing the flow of transmission of upstream data when there are two ONUs 20. In FIG. The flow of transmission of uplink data when there are three or more ONUs 20 is basically the same as the flow of transmission of uplink data shown in FIG.

As shown in FIG. 3, it is assumed that two ONUs 20 ("ONU#1" and "ONU#2") are connected to the OLT 10 here. The OLT 10 collectively receives the transmission request message (REPORT frame) transmitted from ONU#1 and the transmission request message (REPORT frame) transmitted from ONU#2 ((1) in FIG. 3).

When the OLT 10 receives the transmission request messages (REPORT frames) from ONU#1 and ONU#2, it collectively transmits transmission permission messages (GATE frames) to ONU#1 and ONU#2 (Fig. 3 (2)).

Specifically, the OLT 10 grasps the amount of upstream data accumulated in ONU#1 from the transmission request message (REPORT frame) received from ONU#1. The OLT 10 determines the transmission start time and transmission amount of uplink data to be transmitted by the ONU#1 in the next operation cycle based on the grasped data amount. The OLT 10 writes the transmission start time and the amount of transmission of the determined uplink data in ONU#1 in a transmission permission message (GATE frame).

Also, the OLT 10 grasps the amount of upstream data accumulated in ONU#2 from the transmission request message (REPORT frame) received from ONU#2. The OLT 10 determines the transmission start time and transmission amount of uplink data to be transmitted by the ONU#2 in the next operation cycle based on the grasped data amount. The OLT 10 writes the transmission start time and the amount of transmission of the determined uplink data in ONU#2 in a transmission permission message (GATE frame).

As shown in FIG. 3, the OLT 10 collectively transmits the generated transmission permission message (GATE frame) to ONU#1 and ONU#2. ONU#1 and ONU#2 receive the transmission permission message (GATE frame) transmitted from OLT 10 respectively.

ONU#1 and ONU#2 recognize the value of the transmission start time and transmission amount of uplink data specified for their own ONU 20 from the contents described in the transmission permission message (GATE frame). ONU#1 and ONU#2 each transmit the amount of uplink data specified by the transmission permission message (GATE frame) to the OLT 10 at the transmission start time of the uplink data specified by the transmission permission message (GATE frame). ((3) in FIG. 3).

Changes in the amount of upstream data accumulated in the ONU 20 queue will be described below. FIG. 4 is a schematic diagram for explaining changes in the amount of accumulated uplink data.

It should be noted that there are cases where the ONU 20 does not have a granted queue (transmission reservation queue), as shown in FIG. 4 described below. FIG. 5 is a schematic diagram showing an example of the configuration of the granted queue. As shown in FIG. 5, for example, uplink data accumulated in queue #p and uplink data accumulated in queue #q are sequentially transferred to the granted queue (reserved transmission queue) under appropriate control by the scheduler. be transferred.

If the ONU 20 does not have a granted queue (transmission reservation queue), the ONU 20 cannot simultaneously process the transmission of the granted DATA and the above two calculations (that is, the data grant transmission reservation calculation and the REPORT calculation). Therefore, sequential processing is performed. As a result, there is a possibility that the REPORT calculation will not be completed in time for the transmission start time of the transmission request message (REPORT frame) specified by the Report grant of the transmission permission message (GATE frame).

If the REPORT calculation is not completed by the transmission start time of the transmission request message (REPORT frame), the transmission request message (REPORT frame) will not be transmitted from the ONU 20 to the OLT 10, so the next transmission from the OLT 10 to the ONU 20 In the permission message (GATE frame), no Data grant is assigned. As a result, the ONU 20 may become unable to transmit uplink data.

FIG. 4 shows the amount of upstream data accumulated in the ONU 20 queue at six points in time from point (a) to point (f). As shown in FIG. 4, it is assumed here that the ONU 20 has two queues ("queue#p" and "queue#q"). Here, queue #p is a queue in which high-priority uplink data is accumulated, and queue #q is a queue in which low-priority uplink data is accumulated.

First, in the column of point (a), queue #p indicates the amount of uplink data for which the transmission request has been reported (reported) and the amount of uplink data for which transmission has been reserved (granted). there is The queue #q also indicates the amount of uplink data for which transmission requests have been reported (reported) and the amount of uplink data for which transmission has been reserved (granted).

Here, the amount of uplink data (reported) for which the transmission request has been reported is the amount of uplink data that the ONU 20 has already reported to the OLT 10 with the transmission request message (REPORT frame). Further, the amount of uplink data reserved for transmission (granted) here means that transmission is permitted by a transmission permission message (GATE frame) transmitted from the OLT 10 to the ONU 20 in response to the above transmission request message (REPORT frame). This is the data amount of uplink data corresponding to minutes.

The ONU 20 transmits the amount of upstream data (granted DATA) reserved for transmission to the OLT 10 at the transmission timing specified by the received transmission permission message (GATE frame). After that, the amount of uplink data accumulated in queue #p and queue #q changes from the state at time (a) shown in FIG. 4 to the state at time (b).

Next, in the column of point (b), the queue #p contains the amount of uplink data for which a transmission request has been reported (reported) and the amount of uplink data for which a transmission request has not yet been made (that is, the newly added Data amount of uplink data) and are shown. Also, in queue #q, the amount of uplink data for which a transmission request has been reported (reported), the amount of uplink data for which transmission has not been requested (that is, the amount of newly added uplink data), It is shown.

The data amount of unsent requested upstream data here is the data amount of newly generated upstream data after the previous REPORT calculation was performed.

As shown in the column of time (b) in FIG. 4, the data amount (granted) of the upstream data reserved for transmission at time (a) is reduced to , queue #p and queue #q.

Based on the data amount (Data grant) of the uplink data permitted to be transmitted described in the received transmission permission message (GATE frame), the ONU 20 determines the amount of uplink data that can be transmitted in the corresponding cycle in queue #p and queue #q. Calculate the amount (granted) and reserve it for transmission. The amount of uplink data accumulated in queue #p and queue #q changes from the state at time (b) shown in FIG. 4 to the state at time (c).

Next, in the column of time point (c), the queue #p contains the data amount of uplink data reserved for transmission (granted) and the data amount of uplink data not yet requested to be transmitted (that is, the newly added uplink data amount). Data volume of data) and are shown. In queue #q, the amount of uplink data for which a transmission request has already been reported (reported), the amount of uplink data for which transmission has been reserved (granted), and the amount of uplink data for which transmission has not been requested are stored. amount (that is, the data amount of the newly added uplink data) is shown.

In addition, in the column of time (c), based on the data amount (Data grant) of the uplink data whose transmission is permitted, which is described in the transmission permission message (GATE frame), the queue #p in the column of time (b) is changed to the amount of uplink data reserved for transmission (granted). On the other hand, for queue #q, a part of the data amount (reported) of the uplink data for which the transmission request shown in the column of time (b) has been reported is changed to the data amount (granted) for the uplink data for which transmission is reserved. It is shown that

That is, in the column of point (c), for queue #p, which is a high-priority queue, all of the uplink data whose transmission has been requested has been reserved for transmission, but queue #q, which is a low-priority queue , it is indicated that transmission reservation was not made for some of the requested uplink data. This is the data amount (reported) of the uplink data for which the transmission request included in queue #p has been reported, based on the data amount (Data grant) of the uplink data that is permitted to be transmitted described in the transmission permission message (GATE frame). and the data amount (reported) of the uplink data for which the transmission request included in queue #q has already been reported is greater.

When the amount of upstream data reserved for transmission (granted) is determined, the ONU 20 determines the amount of accumulated upstream data (that is, the amount of upstream data to be requested for transmission) to be written in the next transmission request message (REPORT frame). data volume of data). The amount of uplink data accumulated in queue #p and queue #q changes from the state at time (c) shown in FIG. 4 to the state at time (d).

Next, in the column of time (d), queue #p contains the amount of uplink data reserved for transmission (granted) and the amount of uplink data to be requested for transmission (that is, uplink data waiting for transmission request). amount) and are indicated. The queue #q also indicates the amount of uplink data for which transmission has been reserved (granted) and the amount of uplink data to be requested for transmission (that is, the amount of uplink data waiting for a transmission request). .

As shown in the column for time (d) in FIG. 4, the amount of uplink data to be requested for transmission contained in queue #p (for report in FIG. 4) is (ie, the data amount of the newly added uplink data).

On the other hand, the amount of uplink data to be requested for transmission contained in queue #q (for report in FIG. 4) is the amount of uplink data for which transmission has not been requested at time (c) (that is, the amount of uplink data newly added). data amount) and the data amount obtained by subtracting the data amount of uplink data reserved for transmission (granted) from the newly added uplink data amount (reported) for which the transmission request has been reported. This is the total amount of data.

The ONU 20 generates a transmission request message (REPORT frame) describing the total amount of uplink data to be requested for transmission (for report in FIG. 4) contained in queue #p and queue #q calculated above. ONU 20 transmits the generated transmission request message (REPORT frame) to OLT 10 . The amount of uplink data accumulated in queue #p and queue #q changes from the state at time (d) shown in FIG. 4 to the state at time (e).

Next, in the column of time point (e), the queue #p contains the amount of uplink data for which a transmission request has been reported (reported) and the amount of uplink data for which transmission is reserved (granted). ,It is shown. The queue #q also indicates the amount of uplink data for which a transmission request has been reported (reported) and the amount of uplink data for which transmission has been reserved (granted).

Note that the amount of uplink data reserved for transmission is determined from the data amount (reported) of uplink data for which a transmission request has been reported, which is included in queue #p and queue #q shown in the column of time (e) in FIG. The amount of data excluding the amount of data (granted) corresponds to the amount of uplink data (for report in FIG. 4) to be requested for transmission contained in queue #p and queue #q shown in the column of time (d). , and is the data amount of uplink data whose state has changed due to transmission of a transmission request message (REPORT frame) from the ONU 20 to the OLT 10 .

The ONU 20 transmits the amount of upstream data (granted DATA) reserved for transmission to the OLT 10 at the transmission timing specified by the received transmission permission message (GATE frame). After that, the amount of upstream data accumulated in queue #p and queue #q changes from the state at time (e) shown in FIG. 4 to the state at time (f).

Next, in the column of time (f), queue #p indicates the amount of uplink data (reported) for which the transmission request has already been reported. The queue #q also indicates the amount of uplink data (reported) for which the transmission request has been reported.

As shown in the column for time (f) in FIG. 4, the data amount (granted) of the upstream data reserved for transmission at time (d) is reduced to Removed from queue #p and queue #q.

Through the procedure described above, the upstream data accumulated in the ONU 20 queue is sequentially transmitted to the OLT 10 .

As described above, the ONU 20 receives a transmission permission message (GATE frame) and transmits a transmission request message (REPORT frame) (that is, between time (b) and time (d) in FIG. 4). 2), it is necessary to calculate the data amount (granted) of uplink data reserved for transmission contained in queue #p and queue #q and to calculate the data amount of uplink data to be requested for transmission (that is, REPORT calculation). There is

The OLT 10 in this embodiment provides a time (pre-REPORT GAP) for performing data grant transmission reservation calculation and REPORT calculation between the operation cycles of upstream band control. As a result, even an ONU 20 that does not have a granted queue (reserved transmission queue) can complete the REPORT calculation and the like before the transmission start time of the transmission request message (REPORT frame).

Note that the above configuration is a configuration in which the operation cycle is changed by providing a pre-REPORT GAP between operation cycles, but it is not limited to this configuration. For example, if it is not desired to change the operating cycle, the configuration may be such that the time corresponding to the operating cycle-pre-REPORT GAP is changed to the new operating cycle.

FIG. 6 is a diagram showing the flow of transmission of uplink data by PON1 in the embodiment of the present invention. FIG. 6 shows the flow of upstream data transmission when there are two ONUs 20 . The flow of transmission of uplink data when there are three or more ONUs 20 is basically the same as the flow of transmission of uplink data shown in FIG.

As shown in FIG. 6, it is assumed that two ONUs 20 ("ONU#1" and "ONU#2") are connected to the OLT 10 here. The OLT 10 collectively receives the transmission request message (REPORT frame) transmitted from ONU#1 and the transmission request message (REPORT frame) transmitted from ONU#2 ((1) in FIG. 6).

When the OLT 10 receives the transmission request messages (REPORT frames) from ONU#1 and ONU#2, it collectively transmits transmission permission messages (GATE frames) to ONU#1 and ONU#2 (Fig. 6 (2)).

Specifically, the OLT 10 grasps the amount of upstream data accumulated in ONU#1 from the transmission request message (REPORT frame) received from ONU#1. The OLT 10 determines the transmission start time and transmission amount of uplink data to be transmitted by the ONU#1 in the next operation cycle based on the grasped data amount. The OLT 10 writes the determined transmission start time and transmission amount of uplink data in a transmission permission message (GATE frame).

Also, the OLT 10 grasps the amount of upstream data accumulated in ONU#2 from the transmission request message (REPORT frame) received from ONU#2. The OLT 10 determines the transmission start time and transmission amount of uplink data to be transmitted by the ONU#2 in the next operation cycle based on the grasped data amount. The OLT 10 writes the determined transmission start time and transmission amount of uplink data in a transmission permission message (GATE frame).

Also, at this time, the OLT 10 writes the transmission start time in consideration of the pre-REPORT GAP shown in FIG. 6 in the transmission permission message (GATE frame). Specifically, the OLT 10 writes the transmission start time of the REPORT frame and the transmission start time of the uplink data delayed by the pre-REPORT GAP in the transmission permission message (GATE frame).

As shown in FIG. 6, the OLT 10 collectively transmits the generated transmission permission message (GATE frame) to ONU#1 and ONU#2. ONU#1 and ONU#2 receive the transmission permission message (GATE frame) transmitted from OLT 10 respectively. ONU#1 and ONU#2 recognize the transmission start time and the amount of transmission of uplink data designated for their own ONU 20 from the contents described in the transmission permission message (GATE frame).

ONU#1 and ONU#2 transmit a transmission permission message (REPORT frame) at the transmission start time specified by the transmission permission message (GATE frame). As described above, the transmission start time specified by the transmission permission message (GATE frame) takes into consideration the pre-REPORT GAP. Before the transmission start time of (REPORT frame) arrives, the data grant transmission reservation calculation and the REPORT calculation can be completed.

ONU#1 and ONU#2 each transmit the amount of uplink data specified by the transmission permission message (GATE frame) to the OLT 10 at the transmission start time of the uplink data specified by the transmission permission message (GATE frame). ((3) in FIG. 6).

Note that FIG. 7 is a diagram showing the flow of transmission of uplink data by a conventional PON. As shown in FIG. 7, the conventional PON does not consider the pre-REPORT GAP. Therefore, in FIG. 7, for example, in ONU#2, the time from the reception of the transmission permission message (GATE frame) to the transmission start time of the transmission request message (REPORT frame) is considerably shorter than in FIG. It's becoming

As a result, if ONU#2 does not have a granted queue (reserved transmission queue), by the transmission start time of the transmission request message (REPORT frame) specified by the Report Grant of the transmission permission message (GATE frame), REPORT calculation will not be done in time. Report grant indicates the transmission start time of the transmission request message (REPORT frame) permitted by the OLT 10 . If the REPORT calculation cannot be completed by the transmission start time, ONU#2 will not be able to transmit upstream data to the OLT 10 in the next operation cycle.

[Configuration of OLT]
An example of the functional configuration of the OLT 10 will be described below. FIG. 8 is a block diagram showing the functional configuration of the OLT 10 according to the embodiment of the invention.

As shown in FIG. 8, the OLT 10 includes a signal transmission/reception unit 101, a MAC (Media Access Control) processing unit 102, an OAM (Operations, Administration, Maintenance) processing unit 103, and an ONU (Optical Network Unit) identification determination unit. 104, a pre-REPORT GAP database 105, a dynamic band allocation operation unit 106, an MPCP (Multi-Point Control Protocol) processing unit 107, and a signal transmission/reception unit .

The signal transmission/reception unit 101 transmits and receives signals between each ONU and its own OLT 10 . The MAC processing unit 102 performs priority control, transfer processing, and the like. The OAM processing unit 103 executes maintenance/operation management functions. Also, the OAM processing unit 103 acquires ONU information.

The ONU identification determination unit 104 determines whether or not the pre-REPORT GAP is required based on the ONU identifier indicated by the ONU information. If the ONU identification determination unit 104 determines that the pre-REPORT GAP is necessary, it acquires the value of the pre-REPORT GAP corresponding to the ONU identifier from the pre-REPORT GAP database 105, and sends it to the dynamic bandwidth allocation operation unit 106. Output.

FIG. 9 is a diagram showing an example of the configuration of the pre-REPORT GAP database 105. FIG. As shown in FIG. 9, for example, the pre-REPORT GAP database 105 is data in which ONU identifiers and pre-REPORT GAP values are associated with each other. For example, the ONU 20 whose ONU identifier is A does not require a pre-REPORT GAP, the ONU 20 whose ONU identifier is B requires a pre-REPORT GAP of 10 [μs], and the ONU identifier is C. It indicates that a certain ONU 20 requires a pre-REPORT GAP of 15 [μs].

The dynamic bandwidth allocation operation unit 106 changes the setting of the operation cycle so that the pre-REPORT GAP based on the acquired value is provided between the operation cycles of upstream bandwidth control.

The MPCP processing unit 107 recognizes a plurality of ONUs 20 connected to the PON 1, and calculates the RTT (Round Trip Time: round-trip delay time from the OLT 10 to the ONU 20) required for communication between each ONU 20 and its own OLT 10. A measurement function, a function of assigning LLID (Logical Link ID), etc., a multiplexing control function of assigning a time slot to each ONU 20 and multiplexing the upstream burst signal from each ONU 20 on the time axis, and ONU 10 and its own OLT 10 Realize the time synchronization function etc. between

The signal transmission/reception unit 108 transmits and receives signals between the service network and its own OLT 10 via an SNI (Service Node Interface) port.

[Operation of OLT]
An example of the operation of the OLT 10 will be described below. FIG. 10 is a flow chart showing the operation of the OLT 10 according to the embodiment of the invention.

The OAM processing unit 103 monitors connection of a new ONU 20 to the PON1 (step S01). When the OAM processing unit 103 detects that a new ONU 20 is connected to the PON 1 (step S<b>01 ), it outputs the ONU information of the newly connected ONU 20 to the ONU identification determination unit 104 .

The ONU identification determination section 104 acquires ONU information output from the OAM processing section 103 . The ONU identification determination unit 104 identifies the newly connected ONU 20 by specifying the ONU identifier from the acquired ONU information (step S02).

The ONU identification determination unit 104 determines whether or not the identified ONU 20 requires the pre-REPORT GAP (step S03). Specifically, the ONU identification determination unit 104 determines whether the identified ONU 20 is an ONU 20 with a granted queue (transmission reservation queue). Information for identifying whether or not the identified ONU 20 requires the pre-REPORT GAP is pre-stored in a storage medium (not shown) of the OLT 10 or the like. Alternatively, the information for identifying whether the identified ONU 20 requires the pre-REPORT GAP may be stored in the pre-REPORT GAP database 105 shown in FIG. 9, for example.

If it is determined that the identified ONU 20 is not the ONU 20 that requires the pre-REPORT GAP (step S03: NO), the process returns to step S01, and the OAM processing unit 103 starts connecting the new ONU 20 to the PON1. Continue monitoring.

If it is determined that the identified ONU 20 requires the pre-REPORT GAP (step S03: YES), the ONU identification determination unit 104 refers to the pre-REPORT GAP database 105 and identifies the ONU 20 identified in step S02. acquires the pre-REPORT GAP value corresponding to the ONU identifier of . The ONU identification determination unit 104 compares the acquired pre-REPORT GAP value with the currently set pre-REPORT GAP value (step S04).

If the pre-report gap value corresponding to the ONU identifier of the identified ONU 20 is smaller than the currently set pre-report gap value (step S04: NO), the process returns to step S01, and the OAM processing unit 103 continues to monitor new ONU 20 connections to PON1.

If the pre-report GAP value corresponding to the ONU identifier of the identified ONU 20 is larger than the currently set pre-report GAP value (step S04: YES), the ONU identification determination unit 104 determines that the identified ONU 20 output to the dynamic band allocation operation unit 106 the value of the pre-REPORT GAP corresponding to the ONU identifier of .

The dynamic band allocation operation unit 106 acquires the pre-REPORT GAP value output from the ONU identification determination unit 104 . The dynamic band allocation operation unit 106 changes the setting of the operation cycle so that the pre-REPORT GAP is suitable for the connected ONU 20 . Specifically, the dynamic bandwidth allocation operation unit 106 changes the setting of the pre-REPORT GAP during the operation cycle of the upstream bandwidth control to the value obtained above (step S05).

After that, returning to the process of step S01, the OAM processing unit 103 continues to monitor the connection of the new ONU 20 to the PON1. Note that the operation of the OLT 10 shown in the flowchart of FIG. 10 ends when, for example, the PON 1 stops functioning.

As described above, the OLT 10 in this embodiment provides sufficient time (pre-REPORT GAP) to perform data grant transmission reservation calculation and REPORT calculation between the operation cycles of upstream band control. Change the setting of the operation cycle so that it is provided.

With the configuration as described above, the OLT 10 in this embodiment can, even if the ONU 20 does not have a granted queue (reserved transmission queue), It becomes possible to complete the calculations necessary for transmitting uplink data. This improves the upstream throughput.

Here, the calculations necessary for transmitting uplink data are, as described above, the calculation of the amount of uplink data reserved for transmission (granted) and the calculation of the amount of uplink data to be requested for transmission (that is, REPORT calculation).

In addition, with the configuration as described above, the OLT 10 in this embodiment can perform upstream communication even in a PON 1 in which both ONUs 20 with a granted queue and ONUs 20 without a granted queue are accommodated. can be made possible.

According to the above-described embodiment, the bandwidth allocation device includes the detection unit and the setting unit. For example, the bandwidth allocation device is the OLT 1 in the embodiment, the detection unit is the OAM processing unit 103 in the embodiment, and the setting unit is the dynamic bandwidth allocation operation unit in the embodiment.

The detection unit detects that a subscriber line terminating device that does not have a transmission reservation queue that waits for transmission-permitted uplink data until the transmission start time is connected to the passive optical network. For example, the passive optical network is PON1 in the embodiment, the upstream data permitted to be transmitted is the granted DATA in the embodiment, the transmission reservation queue is the granted queue in the embodiment, and the subscriber line terminating equipment is It is ONU20 in embodiment.

The setting unit determines the amount of uplink data permitted to be transmitted in the subscriber line terminating equipment during an operation cycle of uplink band control between the subscriber line terminating equipment and the subscriber line terminating equipment. A calculation time, which is the time required for calculation of the data amount of data and calculation of the data amount of uplink data to be requested for transmission, is provided. For example, the subscriber line terminal equipment is the OLT 10 in the embodiment, and the calculation time is the pre-REPORT GAP in the embodiment.

Also, according to the above-described embodiment, the bandwidth allocation device includes the acquisition unit, the determination unit, and the setting change unit. For example, the bandwidth allocation device is the OLT 1 in the embodiment, the acquisition unit is the OAM processing unit 103 in the embodiment, the determination unit is the ONU identification determination unit 104 in the embodiment, and the setting change unit is the is the dynamic bandwidth allocation operation unit 106 in .

The acquisition unit acquires identification information that identifies the subscriber line terminal equipment connected to the passive optical network. For example, the passive optical network is PON1 in the embodiment, the subscriber line terminal is ONU2 in the embodiment, and the identification information is the ONU identifier in the embodiment.

Based on the identification information, the determining unit determines whether or not the subscriber line terminating equipment has a transmission reservation queue for waiting uplink data permitted to be transmitted until the transmission start time. For example, the uplink data permitted to be transmitted is the granted DATA in the embodiment, and the transmission reservation queue is the granted queue in the embodiment.

When it is determined that the subscriber line terminating equipment does not have a transmission reservation queue, the setting change unit provides a predetermined calculation time between operation cycles of upstream bandwidth control in the passive optical network.

The setting change unit calculates the amount of uplink data to be transmitted out of the amount of uplink data permitted to be transmitted and the amount of uplink data to be requested to be transmitted in the subscriber line terminating equipment. The operation cycle may be changed so as to include the required calculation time. For example, the calculation time is the pre-REPORT GAP in the embodiment.

Note that the bandwidth allocation device may further include a storage unit. For example, the storage unit is the pre-REPORT GAP database 105 in the embodiment. The storage unit stores calculation time information in which identification information and calculation time are associated with each other. The setting change unit may change the operating cycle so that the calculation time specified based on the identification information and the calculation time information is included.

A part or all of the OLT 10 in each of the above-described embodiments may be realized by a computer. In that case, a program for realizing this function may be recorded in a computer-readable recording medium, and the program recorded in this recording medium may be read into a computer system and executed. It should be noted that the "computer system" referred to here includes hardware such as an OS and peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible discs, magneto-optical discs, ROMs and CD-ROMs, and storage devices such as hard discs incorporated in computer systems. Furthermore, "computer-readable recording medium" means a medium that dynamically retains a program for a short period of time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. It may also include something that holds the program for a certain period of time, such as a volatile memory inside a computer system that serves as a server or client in that case. Further, the program may be for realizing a part of the functions described above, or may be capable of realizing the functions described above in combination with a program already recorded in the computer system. It may be implemented using a programmable logic device such as an FPGA (Field Programmable Gate Array).

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes design within the scope of the gist of the present invention.

Reference Signs List 1 PON 30 Optical fiber 40 Optical splitter 101 Signal transmission/reception unit 102 MAC processing unit 103 OAM processing unit 104 ONU identification determination unit 105 Pre-REPORT GAP database 106 Dynamic Band allocation operation unit, 107 MPCP processing unit, 108 signal transmission/reception unit

Claims

a detection unit for detecting that a subscriber line terminating device that does not have a transmission reservation queue that waits until a transmission start time for uplink data permitted to be transmitted is connected to the passive optical network;
Uplink data to be transmitted out of the data amount of the uplink data permitted to be transmitted in the subscriber line terminating equipment during an operation cycle of uplink band control between the subscriber line terminating equipment and the subscriber line terminating equipment a setting unit that provides a calculation time, which is the time required for calculating the amount of data in and calculating the amount of uplink data to be requested for transmission;
A bandwidth allocation device comprising:
an acquisition unit that acquires identification information that identifies a subscriber line terminating device connected to a passive optical network;
a determination unit that determines whether or not the subscriber line terminal device has a transmission reservation queue that waits for transmission-permitted uplink data until a transmission start time, based on the identification information;
a setting change unit that sets a predetermined calculation time between operation cycles of upstream band control in the passive optical network when it is determined that the subscriber line terminating equipment does not have the transmission reservation queue;
A bandwidth allocation device comprising:
The setting change unit calculates an amount of uplink data to be transmitted out of the amount of uplink data permitted to be transmitted, calculates an amount of uplink data to be requested to be transmitted, and 3. The bandwidth allocation device according to claim 2, wherein said operation period is changed so as to include said calculation time which is the time required for the calculation.
A storage unit that stores calculation time information in which the identification information and the calculation time are associated,
4. The bandwidth allocation device according to claim 3, wherein said setting change unit changes said operation period so as to include said calculation time specified based on said identification information and said calculation time information.
a detection unit for detecting that a subscriber line terminating device that does not have a transmission reservation queue that waits until a transmission start time for uplink data permitted to be transmitted is connected to the passive optical network;
a data amount of uplink data to be transmitted out of the data amount of uplink data permitted to be transmitted in the subscriber line terminating apparatus during an operation cycle of uplink band control between the subscriber line terminating apparatus and its own apparatus; a setting unit that provides a calculation time that is the time required for the calculation and the calculation of the amount of uplink data to be requested for transmission;
a transmitting/receiving unit that transmits/receives data to/from the subscriber line terminal device;
subscriber line terminal equipment.
an acquisition unit that acquires identification information that identifies a subscriber line terminating device connected to a passive optical network;
a determination unit that determines whether or not the subscriber line terminal device has a transmission reservation queue that waits for transmission-permitted uplink data until a transmission start time, based on the identification information;
a setting change unit that sets a predetermined calculation time between operation cycles of upstream band control in the passive optical network when it is determined that the subscriber line terminating equipment does not have the transmission reservation queue;
a transmitting/receiving unit that transmits/receives data to/from the subscriber line terminal device;
subscriber line terminal equipment.
a detection step of detecting that a subscriber line terminating equipment having no transmission reservation queue for waiting uplink data permitted to be transmitted until a transmission start time is connected to the passive optical network;
Uplink data to be transmitted out of the data amount of the uplink data permitted to be transmitted in the subscriber line terminating equipment during an operation cycle of uplink band control between the subscriber line terminating equipment and the subscriber line terminating equipment a setting step of providing a calculation time, which is the time required for calculating the amount of data of and calculating the amount of uplink data to be requested for transmission;
band allocation method.
a obtaining step of obtaining identification information identifying a subscriber line terminating unit connected to a passive optical network;
a determination step of determining whether or not the subscriber line terminating equipment has a transmission reservation queue for waiting uplink data permitted to be transmitted until a transmission start time based on the identification information;
a setting change step of providing a predetermined calculation time between operation cycles of upstream bandwidth control in the passive optical network when it is determined that the subscriber line terminating equipment does not have the transmission reservation queue;
band allocation method.