KR101532181B1 - Dynamic allocation device and method in 10 gigabit-capable passive optical network - Google Patents

Abstract

Disclosed are a device and a method for dynamic allocation in a XGPON system. The device for dynamic allocation in a XGPON system comprises: a detection unit for detecting an unused portion of an upstream bandwidth for each queue by monitoring traffic of upstream transmission frames of queues within an optical network unit (ONU); an allocation unit for dynamic allocation of a first upstream bandwidth or a second upstream bandwidth to at least one queue among the queues depending on whether the unused portion is smaller than a predetermined reference value; and a determination unit for determining a method to allocate a remaining bandwidth depending on the size of the remaining bandwidth if the remaining bandwidth exists after the dynamic allocation.

Description

TECHNICAL FIELD [0001] The present invention relates to a dynamic allocation apparatus and a method for allocating a dynamic allocation apparatus in an XGPON system,

The present invention relates to a dynamic allocation apparatus and method in an XGPON system, and more particularly, to a dynamic allocation apparatus and method in an XGPON system that allocates dynamic bandwidths using utilization information of a transmission bandwidth allocated to each of queues.

In the conventional technologies 1 and 2, the optical line termination (OLT) of the optical network sends a transmission request amount per queue in each ONU to a plurality of optical network units (ONUs) by dynamic bandwidth allocation in the XGPON system And a status reporting (SR) scheme in which the queue receiving the command transmits its own transmission request amount to the OLT.

At this time, the transmission request amount is the length of a packet waiting in the queue, and the ONU transmits the transmission request amount to the OLT using the DBRu field. The OLT dynamically allocates a transmission band for each queue, and at the same time, determines whether to send a DBRu field and transmits it to ONUs.

1 is a diagram illustrating an upstream transmission frame structure of an ONU in an XGPON system. Referring to FIG. 1, each transmission frame of an ONU includes an ONU ID for identifying an ONU in an XGTC header. However, since the Alloc-ID information for distinguishing the queues in the ONU is not included, the OLT can not know which queue transmits data or which queue transmits the DBRu only by the information of the transmission frame. Therefore, the OLT can store the information on the dynamic bandwidth allocation result including the uplink transmission time allocated to each ONU of each ONU and the transmission of the DBRu field for each frame time.

Accordingly, in the conventional XGPON system, when the number of queues of the ONU increases, the amount of information on the dynamic bandwidth allocation result including the uplink transmission time allocated to each queue and the transmission of the DBRu field is increased and the memory capacity Which is a problem in implementation of dynamic bandwidth allocation.

Also, in the conventional XGPON system, all operations are synchronized with 125 us frame time, and the maximum size of the up bandwidth allocated in the dynamic bandwidth allocation is also limited by the frame time. Also, if the XGPON system has exhausted all of the upstream bandwidth to some cues as a result of dynamic bandwidth allocation at the current frame time, the upstream bandwidth should be allocated to the remaining cues at the next frame time.

Therefore, in the conventional XGPON system, the OLT has to store the transmission request amount of each queue, and the remaining transmission request amount must be managed by reflecting the uplink bandwidth allocation result of each queue to each transmission request amount of each queue. A separate memory for managing an accurate transmission request amount is required, which may be a problem in implementation of dynamic bandwidth allocation. More specifically, since the conventional XGPON system is represented by BufOcc (buffer occupancy) having a length of 3 bytes of waiting packets in the DBRu, 3 bytes of memory are required per queue to manage the amount of transmission requests, As the number increases, the memory size also increases, which can be a problem when implementing the dynamic bandwidth allocation algorithm.

Prior Art 1: Korean Patent Registration No. 100775426 (Nov. 5, 2007), "Method of allocating bandwidth in GPON system and GPON system" Prior Art 2: Korean Patent Registration No. 100809424 (Feb. 26, 2008), "Dynamic Bandwidth Allocation Apparatus for Optical Subscriber Network and Method Thereof" Prior Art 3: Korean Patent No. 101310906 (2013.09.13), "Apparatus and Method for Dynamic Bandwidth Allocation"

An embodiment of the present invention provides a dynamic allocation apparatus and method in an XGPON system in which information on a DBRu allocation result per frame time of each queue and information on an accurate transmission request amount of each queue are not separately managed.

An embodiment of the present invention provides a dynamic allocation apparatus and method in an XGPON system that determines dynamic bandwidth allocation by monitoring traffic for uplink transmission frames of queues in an ONU without determining dynamic bandwidth allocation based on a transmission request amount to provide.

One embodiment of the present invention provides a dynamic allocation apparatus and method in an XGPON system for allocating a residual bandwidth by determining a uniform allocation scheme and a round robin scheme according to the size of a residual bandwidth.

 In a 10 gigabit-capable passive optical network (XGPON) system according to an embodiment of the present invention,

A sensing unit for monitoring traffic for upstream transmission frames of cues in an optical network unit (ONU) and sensing an unused portion of an upstream transmission bandwidth for each of the cues, An allocation unit for dynamically allocating a first upstream bandwidth or a second upstream bandwidth to at least one of the queues according to whether the current bandwidth is small or not, and, if there is a remaining bandwidth after the dynamic allocation, And a determination unit for determining a bandwidth allocation scheme.

Wherein the allocator is capable of dynamically allocating the first upstream bandwidth to at least one queue having the unused portion smaller than the reference value and allocating the unused portion to the queue with the second reference bandwidth smaller than the reference value, Upstream bandwidth can be dynamically allocated.

Wherein the determining unit further allocates the cue to the size of the equal remaining bandwidth when the size of the equal remaining bandwidth obtained by dividing the size of the remaining bandwidth by the total number of the cues in the ONU is equal to or greater than the minimum transmission length Can be determined.

The determiner may further include a round robin method for allocating at least one of the queues to a size of a minimum remaining bandwidth considering the minimum transmission length when the size of the equal remaining bandwidth is smaller than the minimum transmission length Can be determined.

In a 10 gigabit-capable passive optical network (XGPON) system according to an embodiment of the present invention, the dynamic allocation apparatus allocates an equal residual bandwidth or a minimum residual bandwidth to at least one of the queues according to the determined remaining bandwidth allocation scheme Additional assignments may be added.

A method of dynamic allocation in an XGPON system according to an embodiment of the present invention is a method in which an optical line termination (OLT) of an optical network transmits traffic for upstream transmission frames of cues in an optical network unit (ONU) Detecting at least one unused portion of the uplink transmission bandwidth for each of the queues by monitoring a first upstream bandwidth or a second upstream bandwidth of at least one of the queues according to whether the unused portion is smaller than a predetermined reference value And determining a remaining bandwidth allocation scheme according to the size of the remaining bandwidth if there is a remaining bandwidth after the dynamic allocation.

Wherein the dynamically allocating step dynamically allocates the first upstream bandwidth to at least one queue in which the unused portion is less than the reference value and allocates the unused portion to at least one queue that is equal to or greater than the reference value The second upstream bandwidth can be dynamically allocated every fixed service period.

Wherein the determining of the remaining bandwidth allocation scheme comprises: if the size of the equal residual bandwidth obtained by dividing the size of the residual bandwidth by the total number of the queues in the ONU is greater than or equal to the minimum transmission length, As shown in FIG.

The determining of the remaining bandwidth allocation scheme may further include allocating at least one of the queues as a minimum residual bandwidth considering the minimum transmission length when the size of the equal remaining bandwidth is smaller than the minimum transmission length Round-robin method can be determined.

According to an embodiment of the present invention, information on the DBRu allocation result per frame time of each queue and information on an accurate transmission request amount of each queue are separately managed, so that the system can be easily implemented.

An embodiment of the present invention can determine dynamic bandwidth allocation by monitoring traffic for uplink transmission frames of queues in an ONU without determining a dynamic bandwidth allocation based on a transmission request amount.

In one embodiment of the present invention, the remaining bandwidth can be further allocated by determining the uniform distribution scheme and the round robin scheme according to the size of the remaining bandwidth.

1 is a diagram illustrating an upstream transmission frame structure of an ONU in an XGPON system.
2 is a block diagram illustrating an XGPON system.
3 is a block diagram illustrating a dynamic allocation apparatus in an XGPON system.
4 is an example showing frequency of use of the uplink transmission frame with respect to the transmission bandwidth.
5 is a diagram illustrating an example of dynamically allocating an upstream bandwidth for each of four queues.
6 is a diagram illustrating an example of allocating a residual bandwidth based on the round robin scheme.
7 is a flowchart showing a method of dynamic assignment in the XGPON system.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and accompanying drawings, but the present invention is not limited to or limited by the embodiments.

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 terminology used herein is a term used for appropriately expressing an embodiment of the present invention, which may vary depending on the user, the intent of the operator, or the practice of the field to which the present invention belongs. Therefore, the definitions of these terms should be based on the contents throughout this specification.

2 is a block diagram illustrating an XGPON system.

2, a 10 gigabit-capable passive optical network (XGPON) system includes a plurality of optical network units (ONUs) 200, a passive optical splitter (not shown) And an optical line termination (OLT)

An ONU has a number of queues, and each queue has a class of service. The service class of the XG-PON system is called a T-CONT (transmission container) type. The OLT 300 broadcasts a packet to all the ONUs 200 through a passive optical splitter in a downward direction (direction from the OLT to the ONU). In the upward direction (direction from the ONU to the OLT), only one ONU can transmit a packet to the OLT 300 at a moment because of the characteristics of the hand-light distributor.

Since the XG-PON system uses time division multiplexing (TDM), collision may occur when two or more ONUs transmit packets to the OLT 300 at the same time. In order to prevent the transmission collision, the OLT 300 performs a dynamic bandwidth allocation (DBA) operation for each frame time 125us and converts the result into a BWmap (bandwidth map) to be transmitted to the ONUs 200 . Each cue of the ONUs 200 may be assigned an Alloc-ID (allocation ID) for identification in the system.

GPON (Gigabit PON) is one of the representative standards in PON. Recently, to meet the demand for high-speed bandwidth, GPON technology has been extended to develop XG-PON (10-gigabit-capable GPON) technology. In October 2010, ITU-T announced the G.987.1 and G.987.3 XG-PON standards. The XG-PON can provide 10Gbps downlink speed and 2.5Gbps uplink speed. All operations of the XGPON system are synchronized to a frame time of 125us long. The OLT 300 performs DBA every frame time and can notify the ONUs 200 of the result. The dynamic bandwidth allocation for DBA time frame is performed, and the total length of the dynamic bandwidth allocation width generated by the DBA can not exceed the frame time.

The XG-PON system supports a service class to provide quality of service (QoS), and the service class can be a T-CONT type. One ONU has multiple queues, and each queue has its own T-CONT type. There are four types of T-CONT type, T-CONT types 1, 2, 3, and 4. For T-CONT type 1, static bandwidth allocation (SBA) can be performed without dynamic bandwidth allocation. T-CONT type 1 is provided with fixed bandwidth, T-CONT type 2 is provided with assured bandwidth and T-CONT type 3 is provided with guaranteed bandwidth and nonassured bandwidth bandwidth, and T-CONT type 4 can provide the best-effort bandwidth. The guaranteed bandwidth is the bandwidth that dynamically allocates to each queue at the time of dynamic bandwidth, and the non-guaranteed bandwidth and the best effort bandwidth may be bandwidths that dynamically allocate to each queue in a best effort manner. Hereinafter, the dynamic allocation apparatus in the XGPON system for determining the dynamic bandwidth allocation by monitoring the traffic for the uplink transmission frames of the queues in the ONU will be described in detail with reference to FIG.

3 is a block diagram illustrating a dynamic allocation apparatus in an XGPON system.

Referring to FIG. 3, the dynamic allocation apparatus 300 includes a sensing unit 310, an allocating unit 320, and a determining unit 330.

The sensing unit 310 monitors traffic for uplink transmission frames of cues in an optical network unit (ONU) to detect an unused portion for each of the cues. More specifically, the sensing unit 310 may monitor an unused portion of the transmission bandwidth for each of the queues by monitoring the degree of use of the uplink transmission frames with respect to the transmission bandwidth. Hereinafter, the transmission bandwidth of the uplink transmission frame will be described in detail with reference to FIG.

4 shows an example of the degree of use of the uplink transmission frame with respect to the transmission bandwidth.

Referring to FIG. 4, an uplink transmission frame can be divided into a used part using a transmission bandwidth and an unused part using a transmission bandwidth. At this time, it can be deduced that there is no waiting packet in the queue because the area of the unused portion is large, and it can be inferred that there is a packet waiting in the queue because the area of the unused portion is small.

Referring again to FIG. 3, the allocator 320 dynamically allocates a first upstream bandwidth or a second upstream bandwidth to at least one of the queues according to whether an unused portion is smaller than a preset reference value.

More specifically, the allocator 320 may dynamically allocate the first upstream bandwidth to a queue whose unused portion is smaller than the reference value.

In addition, the allocating unit 320 can dynamically allocate the second uplink bandwidth to a queue having an unused portion equal to or larger than the reference value every fixed service period. More specifically, when the unused portion allocates the first uplink bandwidth only to a queue having an unused portion smaller than the reference value, a queue having an unused portion equal to or larger than the reference value can not be allocated an uplink bandwidth, The second upstream bandwidth can be dynamically allocated to a queue whose unused portion is equal to or larger than a reference value in order to solve a service deficiency, in a certain service period.

The following pseudo code is an example of operations of the sensing unit 310 and the assigning unit 320 according to the embodiment of the present invention.

Here, j represents the Alloc ID of the queue belonging to the ONU, and the queue whose AllocID is j can be denoted by Q (j). B is a first upstream bandwidth, P is a second upstream bandwidth, A (j) is a bandwidth allocated to an actual queue, F is a residual bandwidth, and L is a reference value, C (j) is a variable indicating whether an unused portion is smaller than a reference value L, The bandwidth and Query (j) are variables that are set to 1 every fixed service period. At this time, for example, if the service period of the queue Q (j) is 10 frame hours, Query (j) can be set to 1 every 10 frames.

Referring to the pseudo code, the sensing unit 320 can set C (j) to 1 when the unused portion of the upstream frame is smaller than L, and set C (j) to 0 otherwise.

In addition, the allocator 320 initializes A (j) to 0 before dynamic bandwidth allocation. In addition, when C (j) is 1, the allocating unit 320 allocates B to A (j), initializes C (j) to 0, and updates the remaining bandwidth by subtracting B from the remaining bandwidth.

When the C (j) is 0 and the Query (j) is 1, the assigning unit 320 assigns P to A (j), initializes Query (j) to 0, and subtracts P Thereby updating the remaining bandwidth. Hereinafter, an example of dynamically allocating the upstream bandwidth to the cues in the ONU will be described in detail with reference to FIG.

.

5 is a diagram illustrating an example of dynamically allocating an upstream bandwidth for each of four queues.

5, the identification number of the queue is Alloc-ID 510, the variable indicating whether the unused portion is smaller than the reference value L is C (j) 520, the first upstream bandwidth is B, The bandwidth allocated to the real queue is A (j) (540), the variable set to 1 for each fixed service period is Query (j) 530, and the remaining bandwidth is F (550).

The allocating unit 320 updates the F by allocating B to the first queue having C (j) 520 and Query (j) 530 having 1, and subtracting B from F. [ In addition, the allocator 320 maintains F as it is without allocating the upstream bandwidth to the queue # 2 with C (j) 520 being 0 and Query (j) 530 being 0. In addition, the allocating unit 320 allocates P to the queue # 3 having C (j) 520 = 0 and Query (j) 530 = 1, and updates F by subtracting P from F. The allocator 320 also updates F by assigning B to the fourth queue with C (j) 520 being 1 and Query (j) 530 being 0, and subtracting B from F.

Referring again to FIG. 3, when the remaining bandwidth exists after the dynamic allocation, the determination unit 330 determines the remaining bandwidth allocation scheme according to the size of the remaining bandwidth. More specifically, if there is a remaining bandwidth after the dynamic allocation for the first upstream bandwidth or the second upstream bandwidth, the determining unit 330 may determine the remaining bandwidth allocation scheme according to the size of the remaining bandwidth.

According to one aspect of the present invention, when the size of the equal residual bandwidth obtained by dividing the size of the remaining bandwidth by the total number of the queues in the ONU is equal to or greater than the minimum transmission length, It is possible to determine an even distribution method in which additional allocation is made. For example, the minimum transmission length may be 16 bytes.

According to another aspect of the present invention, when the size of the equal remaining bandwidth is smaller than the minimum transmission length, the determining unit 330 may determine that the round- A round robin method can be determined.

According to an embodiment, in the XGPON system, the dynamic allocation apparatus 300 further includes an additional allocator 340 that further allocates an equal residual bandwidth or a minimum residual bandwidth to at least one of the queues according to the determined remaining bandwidth allocation scheme . Hereinafter, an example of allocating the remaining bandwidth based on the round robin method will be described in detail with reference to FIG.

6 is a diagram illustrating an example of allocating a residual bandwidth based on the round robin scheme.

6, the identification number of the queue is an Alloc-ID 610, the first upstream bandwidth is B, the second upstream bandwidth is P, the bandwidth allocated to the real queue is A (j) 620, The updated bandwidth summing the added and added allocated bandwidth is A (j) update value (630), the minimum remaining bandwidth is R and the updated residual bandwidth is F (640).

In the case where R is additionally allocated to the queue # 2 in the round robin manner, the additional allocator 340 allocates R to queue # 2 having A (j) 620 = 0, subtracts R from F, Update.

In addition, the additional allocator 340 allocates and allocates P and R to the queue # 3, where A (j) 620 has P, subtracts R from F, and updates F again. At this time, if F is less than R, the additional allocator 340 ends the residual bandwidth allocation process and does not allocate R to the next queue.

7 is a flowchart showing a method of dynamic assignment in the XGPON system.

Referring to FIG. 7, in operation 710, the dynamic allocation apparatus monitors traffic for uplink transmission frames of cues in an optical network unit (ONU) to detect an unused upstream bandwidth portion for each cue. More specifically, in step 710, the dynamic allocation apparatus may monitor the degree of use of the uplink transmission frames with respect to the transmission bandwidth to detect an unused portion of the transmission bandwidth for each of the queues.

The dynamic allocation apparatus may dynamically allocate the first uplink bandwidth or the second uplink bandwidth to at least one of the queues depending on whether the unused portion is smaller than a preset reference value in step 720. [

More specifically, in step 720, the dynamic allocation apparatus may dynamically allocate a first upstream bandwidth considering a capacity of a packet waiting for at least one queue in which there is a waiting packet in which an unused portion is smaller than a reference value.

In step 720, the dynamic allocation apparatus may dynamically allocate the second uplink bandwidth to a queue having an unused portion equal to or larger than the reference value every fixed service period.

In step 730, the dynamic allocation apparatus determines a residual bandwidth allocation scheme according to the size of the residual bandwidth if residual bandwidth exists after dynamic allocation. More specifically, in step 730, the dynamic allocation apparatus may determine a remaining bandwidth allocation scheme according to the size of the remaining bandwidth if there is a remaining bandwidth after the dynamic allocation for the first uplink bandwidth or the second uplink bandwidth.

According to one aspect of the present invention, in step 730, if the size of the equal residual bandwidth divided by the total number of the queues in the ONU is equal to or greater than the minimum transmission length, Size can be determined. For example, the minimum transmission length may be 16 bytes.

According to another aspect of the present invention, in step 730, when the size of the equal remaining bandwidth is smaller than the minimum transmission length, the dynamic allocation apparatus allocates at least one queue among the queues to the minimum remaining bandwidth considering the minimum transmission length, A round robin method can be determined.

According to an embodiment, in the XGPON system, the dynamic allocation apparatus may further include allocating an equal remaining bandwidth or a minimum remaining bandwidth to at least one of the queues according to a determined remaining bandwidth allocation scheme.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

200: ONUs
300: OLT, dynamic allocation device
310:
320:
330:
340: additional allocation unit

Claims (12)

A sensing unit for monitoring traffic for upstream transmission frames of cues in an optical network unit (ONU) to sense an unused portion of an upstream transmission bandwidth for each of the cues;
An allocation unit for dynamically allocating a first upstream bandwidth or a second upstream bandwidth to at least one of the queues according to whether the unused portion is smaller than a preset reference value; And
And a determination unit for determining a remaining bandwidth allocation scheme according to the size of the remaining bandwidth when the remaining bandwidth exists after the dynamic allocation
Dynamic allocation in XGPON (10 gigabit-capable passive optical network) systems. The method according to claim 1,
The assigning unit
And dynamically allocating the first upstream bandwidth to at least one queue in which the unused portion is smaller than the reference value
Dynamic allocation device in XGPON system. 3. The method of claim 2,
The assigning unit
And the second upstream bandwidth is dynamically allocated to the queue having the unused portion equal to or larger than the reference value every predetermined service period
Dynamic allocation device in XGPON system. The method according to claim 1,
The determination unit
When the size of the equal remaining bandwidth obtained by dividing the size of the remaining bandwidth by the total number of the queues in the ONU is greater than or equal to the minimum transmission length,
Dynamic allocation device in XGPON system. 5. The method of claim 4,
The determination unit
Determining a round robin scheme for allocating at least one of the queues to a size of a minimum remaining bandwidth considering the minimum transmission length when the size of the equal remaining bandwidth is smaller than the minimum transmission length
Dynamic allocation device in XGPON system. 6. The method of claim 5,
And an additional allocator for additionally allocating an equal remaining bandwidth or a minimum remaining bandwidth to at least one of the queues according to the determined remaining bandwidth allocation scheme
Dynamic allocation device in XGPON system. Optical line termination (OLT) of an optical network monitors traffic for uplink transmission frames of queues in an optical network unit (ONU) to detect unused portions of uplink transmission bandwidth for each of the queues ;
Dynamically allocating a first upstream bandwidth or a second upstream bandwidth to at least one of the queues according to whether the unused portion is smaller than a preset reference value; And
Determining a residual bandwidth allocation scheme based on the size of the residual bandwidth if there is a remaining bandwidth after the dynamic allocation;
A method for dynamic allocation in an XGPON (10 gigabit-capable passive optical network) system. 8. The method of claim 7,
The dynamically allocating step
And dynamically allocating the first upstream bandwidth to at least one queue in which the unused portion is smaller than the reference value
How to dynamically allocate in XGPON system. 9. The method of claim 8,
The dynamically allocating step
The second upstream bandwidth is dynamically allocated to at least one queue in which the unused portion is equal to or larger than the reference value,
How to dynamically allocate in XGPON system. 8. The method of claim 7,
The step of determining the remaining bandwidth allocation scheme
When the size of the equal remaining bandwidth obtained by dividing the size of the remaining bandwidth by the total number of the queues in the ONU is greater than or equal to the minimum transmission length,
How to dynamically allocate in XGPON system. 11. The method of claim 10,
The step of determining the remaining bandwidth allocation scheme
Determining a round robin scheme of allocating at least one of the queues to a size of a minimum remaining bandwidth considering the minimum transmission length when the size of the equal remaining bandwidth is smaller than the minimum transmission length
How to dynamically allocate in XGPON system. A computer-readable recording medium having recorded thereon a program for performing the method of any one of claims 7 to 11.

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