KR20170046012A - Apparatus and Method for Synchronous Dynamic Bandwidth Allocation in EPON - Google Patents

Abstract

The present invention relates to a synchronous dynamic bandwidth allocation method from an optical line terminal to an optical network terminal of an Ethernet passive optical network, which uses a round trip time (RTT) Calculating a correction value (EqD) value for each of the optical network devices so as to have a delay time, and calculating a correction value (EqD) for each of the optical network devices using the correction value (EqD) Receiving a report on the amount of data present in the buffer from each of the optical network devices in a second minimum service interval; and, in a third minimum service interval, In accordance with the reports received from each of the optical network devices, Updating a bandwidth for a transmission, and a step of assigning the updated bandwidth.

Description

[0001] The present invention relates to an apparatus and a method for synchronous dynamic bandwidth allocation in an Ethernet passive optical network,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Ethernet Passive Optical Network (EPON), and more particularly, to an apparatus and method for allocating bandwidth dynamically from an optical line terminal (OLT) to an optical network unit (ONU) ≪ / RTI >

An Ethernet Passive Optical Network (EPON) technology is an optical path switching system in which an optical line terminal (OLT) and a plurality of optical network units (ONUs) are connected via a passive point to a multi- To provide a service of 1 Gb / s.

In EPON technology, a Logical Link Identifier (LLID) value is used to logically distinguish optical network devices, which are allocated through an optical network device discovery process. The optical line terminal uses a bandwidth allocation algorithm to control time so that uplink signals of optical network devices do not collide with each other, and optical network devices are distinguished through LLID.

EPON technology has standardized 10G-EPON technology supporting 10Gb / s transmission service according to user's demand in 2009. Recently, NG-EPON technology has been standardized to provide a transmission bandwidth of 10Gb / s or more. The NG-EPON technology is based on a TDMA-PON (Time Division Multiple Access-PON) scheme supporting a transmission rate of 25 Gb / s through a single wavelength and a hybrid PON scheme supporting transmission speeds of 40 Gb / . In the hybrid PON system, a plurality of channels are used through a WDM system rather than a single channel, and an ONU selects a specific wavelength through a wavelength variable element.

In the conventional EPON technology, bandwidth allocation algorithms that improve bandwidth throughput are used rather than delay. However, as in NG-EPON technology, bandwidth allocation algorithms that minimize delay are required to accommodate wireless backhaul services as application services.

SUMMARY OF THE INVENTION The present invention provides a synchronous dynamic bandwidth allocation apparatus and method that enables dynamic bandwidth allocation in a short delay unit time in an EPON.

The present invention relates to a synchronous dynamic bandwidth allocation method from an optical line terminal to an optical network device of an Ethernet passive optical network, which uses round trip time (RTT) measured in each optical network device during a discovery process period, Calculating a correction value (EqD) value using the round trip time measured so that the optical network devices have the same delay time; calculating a correction value (EqD) value by using the correction value (EqD) Receiving a report on the amount of data present in the buffer from the optical network devices within a second minimum service interval; and transmitting the report from the optical network devices in a third minimum service interval Updates the bandwidth for uplink transmissions to optical network devices according to the received report, And allocating the allocated bands.

The present invention relates to a synchronous dynamic bandwidth allocating apparatus, which uses a Round Trip Time (RTT) of each optical network device during a discovery process interval to calculate a correction value (EqD) for each optical network device to have the same delay time, A bandwidth allocator for allocating a bandwidth for uplink transmission to optical network devices using a correction value EqD within a first minimum service interval, And a report reception unit for receiving a report on the amount of data present in the buffer from each of the optical network devices in the third minimum service interval according to a report received from each of the optical network devices, Updates the bandwidth for uplink transmissions to each of the optical network devices, and allocates the updated bandwidth.

In the EPON, the optical line terminal (OLT) 110 reflects the report values of all the optical network devices by reflecting the distance correction value (EqD) of the optical network devices to the grant information in the transmission bandwidth allocation, Service period to provide efficient dynamic bandwidth allocation.

In addition, the present invention maintains a minimum service interval of 128 us cycles and enables a band transmission band to be allocated in a synchronous manner, thereby providing a short delay time for a wireless backhaul service.

In the dynamic bandwidth allocation of optical network devices in the EPON, transmission bandwidth allocation for the next service interval can be performed without a separate processing delay time for reflecting report values of all optical network devices, It is possible to provide a short latency for the wireless backhaul service required by the NG-EPON.

1 is a diagram illustrating a bandwidth allocation procedure used in an Ethernet passive optical network of a one-to-multiple access scheme.
2 is a diagram illustrating a bandwidth allocation procedure using a Poll-and-Stop Polling scheme in an Ethernet passive optical network of a one-to-multiple access scheme.
3 is a diagram illustrating a bandwidth allocation procedure using an interleaved polling scheme in an Ethernet passive optical network of a one-to-multiple access scheme.
4 is a diagram illustrating a bandwidth allocation procedure using an interleaved polling with stop scheme in an Ethernet passive optical network of a one-to-multiple access scheme.
5 is a diagram illustrating a bandwidth allocation procedure of a synchronous Pipelined Interleaved Polling scheme in an Ethernet passive optical network of a one-to-multiple access scheme according to an embodiment of the present invention.
FIG. 6 illustrates an example of bandwidth allocation of a synchronous Pipelined Interleaved Polling scheme in an Ethernet passive optical network of a one-to-multiple access scheme according to an embodiment of the present invention.
7 is a block diagram of a synchronous dynamic bandwidth allocator in an Ethernet passive optical network according to an embodiment of the present invention.
8 is a flowchart illustrating a synchronous dynamic bandwidth allocation method in an Ethernet passive optical network according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The terms used throughout the specification are defined in consideration of the functions in the embodiments of the present invention and can be sufficiently modified according to the intentions and customs of the user or the operator. It should be based on the contents of.

1 is a diagram illustrating a bandwidth allocation procedure used in an Ethernet passive optical network of a one-to-multiple access scheme.

Referring to FIG. 1, an optical line terminal (OLT) 110 transmits a GATE MPCPDU message that provides bandwidth allocation to an optical network unit (ONU) 120 (S210). At this time, the GATE MPCPDU message includes four Grant Start values and four Grant Length values for bandwidth allocation, and includes four Force Report values for requesting a REPORT MPCPDU message to the optical network unit (ONU) 120 . Then, the optical network unit (ONU) 120 starts transmission according to the Grant Start value using the allocated band information, and determines the transmission time according to the Grant Length value.

The ONU 120 transmits a REPORT MPCPDU message together with user data (USER DATA) to the optical line terminal (OLT) 110 at the allocated time (S220). At this time, it is possible to report up to 8 queues. The REPORT MPCPDU message is used to report the amount of data present in the optical network unit (ONU) 120 buffer to the optical line terminal (OLT)

The optical line terminal (OLT) 110 updates the next bandwidth allocation time according to the report value received from the optical network unit (ONU) 120 and transmits it as a GATE MPCPDU message (S230).

The optical network unit (ONU) 120 transmits data together with the REPORT MPCPDU message for a given bandwidth allocation time in step S220 (S240).

If the optical line terminal (OLT) 110 can not provide the report value requested by the optical network unit (ONU) 120, the optical line terminal (OLT) 110 may request only REPORT MPCPDU message transmission including only four Force Report values (S250). Then, the optical network unit (ONU) 120 transmits only the REPORT MPCPDU message to the optical line terminal 110 (S260).

As described above, the band allocation algorithm used in the EPON has a disadvantage in that the GATE MPCPDU message is sent, the REPORT MPCPDU message is received, and the next GATE MPCPDU message is transmitted. Therefore, this scheme can not guarantee QoS (Quality of Service) required in a wireless backhaul network.

2 is a diagram illustrating a bandwidth allocation procedure using a Poll-and-Stop Polling scheme in an Ethernet passive optical network of a one-to-multiple access scheme.

2, the optical line terminal (OLT) 110 allocates bandwidth to the optical network unit 1 (120-1) through a GATE MPCPDU message (G1) And stops the band allocation until there is reception from the base station.

When the data and the REPORT MPCPDU message R1 are transmitted from the optical network unit 1 120-1, the optical line terminal (OLT) 110 allocates bandwidth for the next optical network unit 2 120-2 GATE MPCPDU message (G2) is transmitted.

When the data and the REPORT MPCPDU message (R2) are transmitted from the optical network unit 2 (120-2), a GATE MPCPDU message (G3) is transmitted for band allocation to the next optical network unit 3 (120-3).

In this manner, the optical line terminal (OLT) 110 sequentially allocates bands to the optical network units (ONU) 120-1, 120-2, and 120-3, 120 - 1, 120 - 2, and 120 - 3 until the REPORT MPCPDU message R 1 is transmitted.

Accordingly, a method has been proposed in which the optical line terminal allocates the GATE MPCPDU message in advance before the data and the Report arrive from the optical network device, which will be described with reference to FIG. 3 and FIG.

3 is a diagram illustrating a bandwidth allocation procedure using an interleaved polling scheme in an Ethernet passive optical network of a one-to-multiple access scheme.

3, the optical line terminal (OLT) 110 transmits a GATE MPCPDU message (G1) to the optical network unit 1 (120-1) for band allocation and transmits a GATE MPCPDU message GATE MPCPDU message (G2) is transmitted.

The optical network devices 1 (120-1) and 2 (120-2) transmit the REPORT MPCPDU message (R1, R2) together with the data at the allocated time.

The optical line terminal (OLT) 110 transmits a GATE MPCPDU message (G3) for bandwidth allocation to the optical network unit 3 (120-3) while data is received from the optical network unit 1 (120-1). Optical network device 3 (120-3) transmits REPORT MPCPDU message (R3) together with the data at the allocated time.

The optical line terminal (OLT) 110 needs to manage the RTT value and the bandwidth request value for each optical network device for this transmission. The transmission order and the transmission time of the optical network devices must be predicted and allocated in advance through these values.

The interleaved polling scheme improves the bandwidth utilization rate and the data transmission delay time compared to the Poll-and-Stop Polling scheme. However, since it transmits the GATE MPCPDU messages by predicting the bandwidth before receiving the REPORT MPCPDU messages from the optical network device, The bandwidth can not be accurately provided.

4 is a diagram illustrating a bandwidth allocation procedure using an interleaved polling with stop scheme in an Ethernet passive optical network of a one-to-multiple access scheme.

4, unlike the interleaved polling scheme, the optical line terminal (OLT) 110 previously transmits GATE MPCPDU messages for optical network optical network devices (ONUs) 120-1, 120-2 and 120-3 (R 1, R 2, and R 3) in the transmission time allocated from the optical network optical network units (ONUs) 120 - 1, 120 - 2 and 120 - ) Is transmitted, and after a predetermined calculation time has elapsed for the next band allocation, the updated GATE MPCPDU message is transmitted.

The Interleaved Polling with Stop method can accurately account for the report reflection problem, which is a disadvantage of the interleaved polling method, but the bandwidth allocation calculation time considering reports of optical network devices is used for the next bandwidth allocation. Therefore, this calculation time wastes bandwidth and delays. Therefore, there is a need for an improved algorithm that can provide delay time and efficient bandwidth allocation required for wireless backhaul services in NG-EPON.

The present invention calculates the round trip time (RTT) value of the optical network optical network units (ONUs) 120-1 to 120-n in the optical line terminal (OLT) 110, The optical network devices (ONUs) 120-1 to 120-n reflect the correction value calculated for the Grant Start value so as to have the same transmission delay time and allocate a transmission band in a synchronous manner.

In the present invention, bandwidth allocation is performed to optical network optical network units (ONUs) 120-1 to 120-n in units of a minimum service interval. According to one embodiment, the Minimum Service Interval may be 128us.

The optical line terminal (OLT) 110 allocates bandwidths to optical network optical network units (ONUs) 120-1 to 120-n synchronously in units of a minimum service interval.

According to one embodiment, a delay-sensitive service uses a short service interval and a service that is relatively less sensitive to delay time uses a long service interval. For example, even if the same bandwidth is allocated, a service sensitive to delay time allocates a grant for every service interval of 50, and a service whose performance is more sensitive than a delay time grants 200 services for every four service intervals .

The synchronous Pipelined Interleaved Polling scheme according to an embodiment of the present invention uses the RTT value measured by the optical network device discovery process to calculate a correction value of each optical network device having the same delay time as Equation (1) EqD).

&Quot; (1) "

In Equation (1), the Discovery Window Time is determined according to the transmission distance. For example, when the maximum transmission distance is 20 km, the service interval time of 256 cycles is set to 256 us.

The correction value calculated as described above is reflected in the Grant Start value as shown in Equation (2) below.

&Quot; (2) "

In Equation (2), the first Timestamp value of the service interval is used as the Start Timestamp value, and the Previous Grant Length value is the Grant Length value assigned to the previous optical network device.

The Grant Start value calculated by Equation (2) is transmitted to the optical network unit (ONU) through the GATE MPCPDU message. Accordingly, all the optical network devices can reach the optical line terminal (OLT) at the same time according to the reflection of the EqD value, thereby providing statistical multiplexing of the transmission band.

5 is a diagram illustrating a bandwidth allocation procedure of a synchronous Pipelined Interleaved Polling scheme in an Ethernet passive optical network of a one-to-multiple access scheme according to an embodiment of the present invention.

Referring to FIG. 5, in the synchronous Pipelined Interleaved Polling (OPS) scheme according to an embodiment of the present invention, the optical line terminal (OLT) 110 transmits the optical network devices 120-1, 120-2, G3, G3, and G3 to G3, G3, and G3.

The optical line terminal (OLT) 110 distributes the bandwidth allocation for the N + 1 service interval in the N service interval, and then transmits the GATE MPCPDU message, and adjusts the information by reflecting the EqD to the Grant Start value. Each of the ONUs 120-1, 120-2, and 120-3 transmits the data and the REPORT MPCPDU message during the allocated transmission time using the Grant Start value and the Grant Length value of the received GATE MPCPDU message .

The optical line terminal (OLT) 110 allocates bandwidths for N + 2 service periods using report information of the optical network devices 120-1, 120-2, and 120-3 received in the (N + 1) And then allocates the updated transmission time through the GATE MPCPPDU messages. That is, the Report value received in the previous service interval is calculated in advance through the bandwidth allocation of the synchronous scheme and is reflected in the bandwidth allocation of the next service interval. In this manner, the Pipelined Interleaved Polling scheme according to the present invention can utilize the transmission time without wasting bandwidth.

FIG. 6 illustrates an example of bandwidth allocation of a synchronous Pipelined Interleaved Polling scheme in an Ethernet passive optical network of a one-to-multiple access scheme according to an embodiment of the present invention.

6, the optical network unit 1 (ONU 1) 120-1 is located at a distance of 5 km from the optical line terminal (OLT) 110, and the optical network unit 2 (ONU 2) 120-2, Is located at a distance of 10 km from the optical line terminal (OLT) 110. At this time, the Discovery Window is 100us.

Then, the RTT of optical network unit 1 (0NU 1) 120-1 is calculated as 25us, and the RTT of optical network unit 2 (ONU 2) 120-2 is calculated as 50us. Therefore, the EqD of the optical network unit 1 (ONU 1) 120-1 becomes 50 us and the optical network unit 2 (ONU 2) 120-2 becomes 0 us.

The optical line terminal (OLT) 110 adds an EqD value of 50us to the start time of the current cycle (100us) for bandwidth allocation from 200us to 20us in the optical network unit 1 (ONU 1) 120-1, Grant Start value is assigned.

The optical network unit 1 (ONU 1) (`120-1`) has a time period synchronized with the optical line terminal (OLT) 110 after 25us time of the optical line terminal (OLT) 110 and arrives at a time of 150us , The data is transmitted for 20 us.

The optical line terminal (OLT) 110 allocates a Grant Start value of 130us to the optical network unit 2 (ONU 2) 120-2 after 10us to allocate a transmission time of 60us.

This is calculated as 20us transmission time of optical network unit 1 (ONU 1) 120-1 and guard time of 10us. The optical network unit 2 (ONU 2) 120-2 has a time period synchronized with the optical line terminal (OLT) 110 after 50us time from the optical line terminal (OLT) 110, Data will be transmitted for 60us. Therefore, the optical line terminal (OLT) 110 dynamically allocates a Grant Start value and a Grant Length value by reflecting the Report values of the optical network units 120-1, 120-2, and 120-3 every cycle time do.

7 is a block diagram of a synchronous dynamic bandwidth allocator in an Ethernet passive optical network according to an embodiment of the present invention.

Referring to FIG. 7, in the Ethernet passive optical network, a synchronous dynamic bandwidth allocating apparatus includes a delay calculating unit 810, a bandwidth allocating unit 820, and a report receiving unit 830.

The delay calculator 810 calculates a correction value EqD for each of the optical network devices using the Round Trip Time (RTT) of each of the optical network devices during the discovery process period so as to have the same delay time .

The delay calculation unit 810 includes a round trip time calculation unit 811 and a correction value calculation unit 812 in detail. The round trip time calculation unit 811 calculates a round trip time (RTT) of each of the optical network devices. The correction value calculation unit 812 calculates the correction value (EqD) value using the calculated RTT so that the optical network devices have the same delay time. The correction value calculator 812 calculates the Discovery Window Time as in Equation (1), subtracts twice the value of the RTT from the found window time, and outputs the correction value EqD .

In addition, the delay calculator 810 may store the correction value EqD for each optical network device in the table 813.

The bandwidth allocator 820 allocates a bandwidth for uplink transmission to each of the optical network devices using the correction value EqD within the first minimum service interval. In detail, the bandwidth allocating unit 820 includes a start time calculating unit 821 and a bandwidth allocation message transmitting unit 822.

The start time calculating unit 821 calculates an uplink transmission start time (Grant Start) for each of the optical network devices by using the calculated correction value EqD. The minimum start time A start timestamp value, a correction value EqD, a Grant Length value previously allocated to the optical network device and a guard time, which are values of the first Timestamp of the Minimum Service Interval, .

The bandwidth allocation message transmission unit 822 transmits a bandwidth allocation message including information on an uplink transmission start time (Grant Start) calculated for each optical network device and a transmission time (Grant length) for uplink transmission, To each of the devices.

The report receiving unit 830 receives a report on the amount of data present in the buffer from each of the optical network devices within the second minimum service interval.

Then, within the third minimum service interval, the bandwidth allocator 820 allocates bandwidth allocation information for uplink transmission to each of the optical network devices so that the optical network devices have the same delay time, according to the report received from each of the optical network devices. Updates the band, and allocates the updated band. That is, the start time calculating unit 821 calculates the start time (Grant) of the optical network devices based on the amount of data included in the received report message, using the previously calculated correction value (EqD) Start) and the transmission time (Grant length) for uplink transmission. Then, the bandwidth allocation message transmission unit 822 transmits a bandwidth allocation message including the updated uplink transmission start time (Grant Start) and the transmission time for uplink transmission to each of the optical network devices.

8 is a flowchart illustrating a synchronous dynamic bandwidth allocation method in an Ethernet passive optical network according to an embodiment of the present invention.

Referring to FIG. 8, the optical line terminal (OLT) 110 measures RTT values of one or more optical network units (ONUs) through a discovery process (S710).

Then, the optical line terminal (OLT) 110 calculates the correction value EqD of each optical network unit (ONU) using the RTT values of the optical network units (ONUs) (S720). At this time, the optical line terminal (OLT) 110 calculates the correction value EqD of each optical network unit (ONU) using Equation (1). The EqD values for all the optical network devices calculated during the Discovery Process by the optical line terminal (OLT) 110 may be stored in a separate EqD table. The optical line terminal (OLT) 110 calculates and stores service interval and service byte information for each optical network device in accordance with an SLA (Service Level Agreement) agreement of optical network devices.

The optical line terminal (OLT) 110 calculates the Grant Start value using Equation (2) using the EqD value for each minimum service interval, and determines the GTE MPCPDU message transmission period based on the service interval value. Then, the Grant Length value, i.e., the bandwidth, of the GATE MPCPDU message is determined and allocated according to the value of the service byte.

That is, within the first minimum service interval, the optical line terminal (OLT) 110 calculates an uplink transmission start time (Grant Start) for each of the optical network devices using the calculated correction value EqD (S930 ). Then, the optical line terminal (OLT) 110 transmits a bandwidth allocation message including information on an uplink transmission start time (Grant Start) calculated for each optical network device and a transmission time (Grant length) To each of the optical network devices (S940).

Also, the optical line terminal (OLT) 110 updates the Grant Length value of the next cycle by applying the report value of the optical network device received every minimum service interval. That is, in the second minimum service interval, the optical line terminal (OLT) 110 receives a report on the amount of data present in the buffer from each of the optical network devices (S950).

Then, at the third minimum service interval, the optical line terminal (OLT) 110 transmits the previously calculated correction value EqD for each of the optical network devices according to the amount of data included in the received report message, (Grant Start) and the transmission time (Grant length) for uplink transmission are updated using the uplink transmission start time (S960).

The optical line terminal (OLT) 110 transmits a bandwidth allocation message including the updated uplink transmission start time (Grant Start) and a transmission time for uplink transmission to each of the optical network devices (S970 ).

Claims (13)

A method of synchronous dynamic bandwidth allocation from an optical line terminal to an optical network device in an Ethernet passive optical network, the method comprising: during a discovery process interval, using a round trip time (RTT) Calculating a correction value (EqD) value for each of the optical network devices to have a value
Allocating a bandwidth for uplink transmission to each optical network device using a correction value (EqD) within a first minimum service interval;
Receiving, within a second minimum service interval, a report on the amount of data present in the buffer from each of the optical network devices;
Within a third minimum service interval, updates the bandwidth for uplink transmissions to each of the optical network devices such that the optical network devices have the same delay time, according to a report received from each of the optical network devices, The method comprising: allocating a dynamic bandwidth allocation scheme to a plurality of users;
2. The method of claim 1, wherein calculating the correction value (EqD)
Calculating a round trip time (RTT) of each of the optical network devices,
And calculating a correction value (EqD) value using the calculated RTT so that the optical network devices have the same delay time.
2. The method of claim 1, wherein allocating the band comprises:
Calculating an uplink transmission start time (Grant Start) for each of the optical network devices using the calculated correction value (EqD)
Transmitting to each of the optical network devices a bandwidth allocation message including information on an uplink transmission start time (Grant Start) calculated for each of the optical network devices and a transmission time (Grant length) for uplink transmission, Wherein the synchronous dynamic bandwidth allocation method comprises the steps of:
The method of claim 1, wherein allocating the updated bandwidth comprises:
(EqD) for each of the optical network devices according to the amount of data included in the received report message, and transmits the uplink transmission start time (Grant Start) and the transmission time for uplink transmission Updating a grant length,
And transmitting a bandwidth allocation message including the updated uplink transmission start time (Grant Start) and a transmission time for uplink transmission to each of the optical network devices. Assignment method.
3. The method of claim 2, wherein calculating the correction value (EqD)
Calculating a Discovery Window Time,
And calculating the correction value (EqD) by subtracting twice the value of the RTT from the found window time.
4. The method of claim 3, wherein calculating the uplink transmission start time (Grant Start)
A Start Timestamp value, a correction value EqD, a Grant Length value previously assigned to the optical network device, and a guard time value, which are the first Timestamp values of the Minimum Service Interval, (Guard Time) of the synchronous dynamic bandwidth allocation method.
A delay calculation section for calculating a correction value (EqD) value for each of the optical network devices so as to have the same delay time, using Round Trip Time (RTT) of each of the optical network devices during the discovery process interval;
A bandwidth allocator for allocating a bandwidth for uplink transmission to each optical network device using a correction value (EqD) within a first minimum service interval,
And a report receiver for receiving a report on the amount of data present in the buffer from each of the optical network devices in a second minimum service interval,
The band allocation unit
Within a third minimum service interval, updates the bandwidth for uplink transmissions to each of the optical network devices such that the optical network devices have the same delay time, according to a report received from each of the optical network devices, And allocating the dynamic bandwidth allocation unit to the synchronous dynamic bandwidth allocation unit.
8. The apparatus of claim 7, wherein the delay calculator
A round trip time calculation unit for calculating a round trip time (RTT) of each of the optical network devices,
And a correction value calculator for calculating a correction value (EqD) value using the calculated RTT so that the optical network devices have the same delay time.
8. The apparatus of claim 7, wherein the band allocator
A start time calculating section for calculating an uplink transmission start time (Grant Start) for each of the optical network devices using the calculated correction value (EqD)
A bandwidth allocation message for transmitting a bandwidth allocation message including information on an uplink transmission start time (Grant Start) calculated for each of the optical network devices and a transmission time (Grant length) for uplink transmission to each of the optical network devices And a message transmission unit.
The apparatus as claimed in claim 9, wherein the start time calculating unit
(EqD) for each of the optical network devices according to the amount of data included in the received report message, and transmits the uplink transmission start time (Grant Start) and the transmission time for uplink transmission (Grant length)
The bandwidth allocation message transmission unit
And transmits a bandwidth allocation message including the updated uplink transmission start time (Grant Start) and a transmission time for uplink transmission to each of the optical network devices.
The apparatus as claimed in claim 8, wherein the correction value (EqD)
And calculates the correction value (EqD) by subtracting a value twice the RTT from the found window time.
The apparatus as claimed in claim 9, wherein the start time calculating unit
A Start Timestamp value, a correction value EqD, a Grant Length value previously assigned to the optical network device, and a guard time value, which are the first Timestamp values of the Minimum Service Interval, (Guard Time) of the synchronous dynamic bandwidth allocation apparatus.
8. The apparatus of claim 7, wherein the delay calculator
And a correction value (EqD) for each optical network device is stored in a table.

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