OPTICAL LINE TERMINAL, DYNAMIC BANDWIDTH ALLOCATION METHOD, AND OPTICAL COMMUNICATION NETWORK

• US 20120213518A1
• Filed: 02/10/2012
• Published: 08/23/2012
• Est. Priority Date: 02/18/2011
• Status: Active Grant

• Current Assignee: OKI Electric Industry Company Limited
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: TAMAI, Hideaki, Hisano, Ryuji
• Granted Patent: US 8,879,911 B2
• Time in Patent Office: Days
• US Class Current: 398/58
• CPC Class Codes: H04J 14/0247 Sharing one wavelength for at least a group of ONUs
• CPC Class Codes: H04J 14/0252 Sharing one wavelength for at least a group of ONUs, e.g. for transmissions from-ONU-to-OLT or from-ONU-to-ONU
• CPC Class Codes: H04J 14/0282 WDM tree architectures
• CPC Class Codes: H04L 47/72 using reservation actions during connection setup
• CPC Class Codes: H04Q 11/0067 Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
• CPC Class Codes: H04Q 2011/0064 Arbitration, scheduling or medium access control aspects

Abstract

There is provided an optical line terminal that dynamically allocates communication bandwidth to a plurality of optical network units in an optical communication network, the optical line terminal including a minimum bandwidth allocation unit calculating allocation bandwidth of the plurality of optical network units based on bandwidth request information notified by the plurality of optical network units, a comparison unit comparing an allocation cycle given as the sum total of allocation bandwidth allocated to the plurality of optical network units respectively with a predetermined threshold value, a best-effort bandwidth allocation unit calculating remaining bandwidth as best-effort bandwidth of the plurality of optical network units when the allocation cycle is less than the threshold value, and a bandwidth allocation unit allocating communication bandwidth of the plurality of optical network units based on the allocation bandwidth and the best-effort bandwidth.

Claims

1. An optical line terminal dynamically allocating communication bandwidth to a plurality of optical network units in an optical network, the optical line terminal comprising:

a minimum bandwidth allocation unit calculating allocation bandwidth of the plurality of optical network units based on bandwidth request information notified by the plurality of optical network units;

a comparison unit comparing an allocation cycle given as a sum total of the allocation bandwidth allocated to the plurality of optical network units respectively with a predetermined threshold value;

a best-effort bandwidth allocation unit calculating remaining bandwidth as best-effort bandwidth of the plurality of optical network units when the allocation cycle is less than the threshold value; and

a bandwidth allocation unit allocating the communication bandwidth of the plurality of optical network units based on the allocation bandwidth and the best-effort bandwidth.

2. The optical line terminal according to claim 1,

wherein when the allocation cycle is less than the threshold value, the best-effort bandwidth allocation unit calculates the remaining bandwidth based on a difference between the threshold value and the allocation cycle, and calculates the remaining bandwidth as the best-effort bandwidth of the plurality of optical network units.

3. The optical line terminal according to claim 2,

wherein when the allocation cycle is less than the threshold value, the best-effort bandwidth allocation unit calculates the remaining bandwidth based on the difference between the threshold value and the allocation cycle, and calculates the remaining bandwidth as the respective best-effort bandwidth of the plurality of optical network units based on any one of rates of contract bandwidth of respective users of the plurality of optical network units and rates of the allocation bandwidth of the plurality of optical network units of the minimum bandwidth allocation unit.

4. The optical line terminal according to claim 1,

wherein when the allocation cycle is less than the threshold value, the bandwidth allocation unit sets bandwidth totaling the allocation bandwidth and the best-effort bandwidth as the communication bandwidth, notifies the communication bandwidth to any of the plurality of optical network units, and allocates the communication bandwidth.

5. The optical line terminal according to claim 1,

wherein when the allocation cycle is greater than the threshold value, the bandwidth allocation unit sets the allocation bandwidth as the communication bandwidth, notifies the communication bandwidth to any of the plurality of optical network units, and allocates the communication bandwidth.

6. The optical line terminal according to claim 1, the optical line terminal exchanging control signals and data signals with the plurality of optical network units respectively,

wherein the threshold value is a sum total of:

a period during which the optical line terminal receives the control signals from the plurality of optical network units;

a period during which the optical line terminal calculates bandwidth to be allocated to the plurality of optical network units; and

a period during which the optical line terminal transmits the control signals to the plurality of optical network units.

7. The optical line terminal according to claim 1, the optical line terminal periodically exchanging control signals and data signals with the plurality of optical network units respectively,

wherein the allocation bandwidth of the plurality of optical network units calculated by the minimum bandwidth allocation unit, the best-effort bandwidth calculated by the best-effort bandwidth allocation unit, and the communication bandwidth of the plurality of optical network units allocated by the bandwidth allocation unit are bandwidth related to reception of the data signals.

8. The optical line terminal according to claim 1, wherein

the bandwidth request information notified by the plurality of optical network units includes a bandwidth request length expressed in a packet length as request bandwidth, and

the minimum bandwidth allocation unit calculates, as the allocation bandwidth of the plurality of optical network units, a period spent to receive a length of a packet of the bandwidth request length included in the bandwidth request information notified by the plurality of optical network units.

9. The optical line terminal according to claim 1, wherein

the bandwidth request information notified by the plurality of optical network units includes a plurality of bandwidth request lengths expressed in packet lengths as request bandwidth, and

the minimum bandwidth allocation unit acquires a smallest bandwidth request length among the plurality of bandwidth request lengths included in the bandwidth request information notified by the plurality of optical network units, and calculates, as the allocation bandwidth of the plurality of optical network units, a period spent to receive a length of a packet of the smallest bandwidth request length.

10. The optical line terminal according to claim 9,

wherein the plurality of bandwidth request lengths include a shortest request length of a smallest packet length and a longest request length of a largest packet length as bandwidth that any of the plurality of optical terminal units requests from the optical line terminal.

11. A dynamic bandwidth allocation method in an optical line terminal in an optical communication network configured in a manner that the optical line terminal is connected to a plurality of optical network units, the dynamic bandwidth allocation method comprising:

calculating allocation bandwidth of the plurality of optical network units based on bandwidth request information notified by the plurality of optical network units to allocate minimum bandwidth;

comparing allocation cycle given as a sum total of the allocation bandwidth allocated to the plurality of optical network units respectively with a predetermined threshold value;

when the allocation cycle is less than the threshold value, calculating remaining bandwidth as best-effort bandwidth of the plurality of optical network units to allocate the best-effort bandwidth; and

allocating communication bandwidth of the plurality of optical network units based on the allocation bandwidth and the best-effort bandwidth.

12. The dynamic bandwidth allocation method in the optical communication network according to claim 11, wherein when the allocation cycle is less than the threshold value, the best-effort bandwidth allocation step includes:

calculating the remaining bandwidth based on a difference between the threshold value and the allocation cycle; and

calculating the remaining bandwidth as the best-effort bandwidth of the plurality of optical network units.

13. The dynamic bandwidth allocation method in the optical communication network according to claim 12, wherein when the allocation cycle is less than the threshold value, the best-effort bandwidth allocation step includes:

calculating the remaining bandwidth based on the difference between the threshold value and the allocation cycle; and

calculating the remaining bandwidth as the respective best-effort bandwidth of the plurality of optical network units based on any one of rates of contract bandwidth of respective users of the plurality of optical network units and rates of the allocation bandwidth of the plurality of optical network units in the minimum bandwidth allocation step.

14. The dynamic bandwidth allocation method in the optical communication network according to claim 11, wherein when the allocation cycle is less than the threshold value, the bandwidth allocation step includes:

setting bandwidth totaling the allocation bandwidth and the best-effort bandwidth as the communication bandwidth;

notifying the communication bandwidth to any of the plurality of optical network units; and

allocating the communication bandwidth.

15. The dynamic bandwidth allocation method in the optical communication network according to claim 11, wherein when the allocation cycle is greater than the threshold value, the bandwidth allocation step includes:

setting the allocation bandwidth as the communication bandwidth;

notifying the communication bandwidth to any of the plurality of optical network units; and

allocating the communication bandwidth.

16. An optical communication network configured in a manner that an optical line terminal is connected to a plurality of optical network units,

the optical line terminal comprising:

a optical line terminal controller; and

an upstream signal receiver separating an upstream signal received from the optical network unit into an upstream control signal and an upstream data signal, and transmitting the upstream control signal to the optical line terminal controller,

wherein the optical line terminal controller further includes;

a control signal reading/generating unit reading a bandwidth request notified by the optical network unit from the upstream control signal;

a minimum bandwidth allocation unit calculating allocation bandwidth of the plurality of optical network units based on the bandwidth request;

a comparison unit comparing an allocation cycle given as a sum total of the allocation bandwidth allocated to the plurality of optical network units respectively with a predetermined threshold value;

a best-effort bandwidth allocation unit calculating remaining bandwidth as best-effort bandwidth of the plurality of optical network units when the allocation cycle is less than the threshold value; and

a bandwidth allocation unit allocating communication bandwidth of the plurality of optical network units based on the allocation bandwidth and the best-effort bandwidth.

17. The optical communication network according to claim 16,

wherein when the allocation cycle is less than the threshold value, the best-effort bandwidth allocation unit calculates the remaining bandwidth based on a difference between the threshold value and the allocation cycle, and calculates the remaining bandwidth as the best-effort bandwidth of the plurality of optical network units.

18. The optical communication network according to claim 17,

wherein when the allocation cycle is less than the threshold value, the best-effort bandwidth allocation unit calculates the remaining bandwidth based on the difference between the threshold value and the allocation cycle, and calculates the remaining bandwidth as the respective best-effort bandwidth of the plurality of optical network units based on any one of rates of contract bandwidth of respective users of the plurality of optical network units and rates of the allocation bandwidth of the plurality of optical network units of the minimum bandwidth allocation unit.

19. The optical communication network according to claim 16,

wherein when the allocation cycle is less than the threshold value, the bandwidth allocation unit sets bandwidth totaling the allocation bandwidth and the best-effort bandwidth as the communication bandwidth, notifies the bandwidth to any of the plurality of optical network units, and allocates the communication bandwidth.

20. The optical communication network according to claim 16,

wherein when the allocation cycle is greater than the threshold value, the bandwidth allocation unit sets the allocation bandwidth as the communication bandwidth, notifies the communication bandwidth to any of the plurality of optical network units, and allocates the communication bandwidth.