Dynamic bandwidth allocation and service differentiation for broadband passive optical networks

• US 20060268704A1
• Filed: 04/17/2006
• Published: 11/30/2006
• Est. Priority Date: 04/15/2005
• Status: Active Grant

• Current Assignee: New Jersey Institute of Technology
• Original Assignee: New Jersey Institute of Technology
• Inventors: Ansari, Nirwan, Luo, Yuanqiu
• Granted Patent: US 7,808,913 B2
• Time in Patent Office: Days
• US Class Current: 370/230
• CPC Class Codes: H04J 14/0226 Fixed carrier allocation, e.g. according to service
• CPC Class Codes: H04J 14/0227 Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
• 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: H04J 3/1694 Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers Passive Optical Networks H04Q11/0062
• CPC Class Codes: H04L 47/15 in relation to multipoint traffic arrangements for broadcast or multicast in data networks H04L12/18
• CPC Class Codes: H04L 47/2433 Allocation of priorities to traffic types
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 47/788 Autonomous allocation of resources
• CPC Class Codes: H04L 47/805 QOS or priority aware
• CPC Class Codes: H04L 47/83 based on usage prediction
• 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
• CPC Class Codes: H04Q 2011/0084 Quality of service aspects

Abstract

A dynamic upstream bandwidth allocation scheme is disclosed, i.e., limited sharing with traffic prediction (LSTP), to improve the bandwidth efficiency of upstream transmission over PONs. LSTP adopts the PON MAC control messages, and dynamically allocates bandwidth according to the on-line traffic load. The ONU bandwidth requirement includes the already buffered data and a prediction of the incoming data, thus reducing the frame delay and alleviating the data loss. ONUs are served by the OLT in a fixed order in LSTP to facilitate the traffic prediction. Each optical network unit (ONU) classifies its local traffic into three classes with descending priorities: expedited forwarding (EF), assured forwarding (AF), and best effort (BE). Data with higher priority replace data with lower priority when the buffer is full. In order to alleviate uncontrolled delay and unfair drop of the lower priority data, the priority-based scheduling is employed to deliver the buffered data in a particular transmission timeslot. The bandwidth allocation incorporates the service level agreements (SLAs) and the on-line traffic dynamics. The basic limited sharing with traffic prediction (LSTP) scheme is extended to serve the classified network traffic.

Claims

1. In a communication network including a terminal which serves a plurality of downstream network units and receives upstream communications from the network units in respective time slots on a time division basis, the terminal apportioning upstream bandwidth among network units by granting a terminal-determined variable duration to the respective timeslots of network units in response to a request from a network unit, a network unit storing local information received thereby and destined for the terminal, a method for allocating a timeslot to a network unit, a method for providing network bandwidth allocation to the network terminals comprising causing the unit'"'"'s requested duration to include the transmission time of stored local data awaiting transmission from the network unit to the terminal as well as a waiting time which is an estimate of the time required to transmit from the unit to the terminal that data which is expected to be received in the interval between the request and the initiation of transmission from the unit to the terminal after receiving the grant.

2. The method of claim 1 performed in a network wherein the terminal is an optical line terminal located at a service provider'"'"'s central office and the network units are optical network units, optically linked to the terminal.

3. The method of claim 2 wherein the terminal is a passive splitter for downstream communication.

4. The method of claim 1 wherein a request is sent by the unit at the conclusion of sending a burst of data, the estimate of time being the time required to transmit data received in the interval between the request and the next following initiation of transmission from the unit to the terminal.

5. The method of claim 1 performed in a network wherein sets of information are stored by a network unit, each member of a set of local information having one of a plurality of predefined priority levels, the method further comprising, at a network unit, maintaining a buffer of members to be transmitted to the terminal, enqueing members for transmission to the terminal in queues each dedicated to members of a specific priority, and in the interval between a network unit request and a following transmission of data thereby, replacing data in the buffer with data being received which is of a higher priority when the buffer is full.

6. The method of claim 5 performed in a network wherein the terminal is an optical line terminal located at a service provider'"'"'s central office and the network units are optical network units, optically linked to the terminal.

7. The method of claim 6 wherein the terminal is a passive splitter for downstream communication.

8. The method of claim 5 wherein a request is sent by the unit at the conclusion of sending a burst of data, the estimate of time being the time required to transmit data received in the interval between the request and the next following initiation of transmission from the unit to the terminal.

9. The method of claim 5 wherein there are three priorities defined, in descending order of priority, as top priority for members which are delay sensitive and have bandwidth guarantees, second priority for members which are not delay sensitive but have bandwidth guarantees, and low priority for members which are not delay sensitive and do not have bandwidth guarantees.

10. In a communication network including a terminal which serves a plurality of downstream network units and receives upstream communications from the network units in respective time slots on a time division basis, the terminal apportioning upstream timeslots among network units by granting a respective timeslot of to network units in response to a request from a network unit, a network unit storing sets of local information received thereby and destined for the terminal, each member of a set of local information having one of a plurality of predefined priority levels, a method providing service differentiation among information sets of different priority comprising, at a network unit, maintaining a buffer of members to be transmitted to the terminal, enqueing members for transmission to the terminal in queues each dedicated to members of a specific priority, in the interval between a network unit request and a following transmission of data thereby, replacing data in the buffer with data being received which is of a higher priority when the buffer is full.

11. The method of claim 10 wherein there are three priorities defined, in descending order of priority, as top priority for members which are delay sensitive and have bandwidth guarantees, second priority for members which are not delay sensitive but have bandwidth guarantees, and third priority for members which are not delay sensitive and do not have bandwidth guarantees

12. In a communication network including a terminal which serves a plurality of downstream network units and receives upstream communications from the network units in respective time slots on a time division basis, the terminal apportioning upstream bandwidth among network units by granting a terminal-determined variable duration to the respective timeslots of network units in response to a request from a network unit, a network unit storing local information received thereby and destined for the terminal, a method for allocating a timeslot to a network unit, the improvement comprising a network unit being constructed so that its requested duration includes the transmission time of stored local data awaiting transmission from the network unit to the terminal as well as a waiting time which is an estimate of the time required to transmit from the unit to the terminal that data which is expected to be received in the interval between the request and the initiation of transmission from the unit to the terminal after receiving the grant.

13. The improved network unit of claim 12 wherein the terminal is an optical line terminal located at a service provider'"'"'s central office and the network units are optical network units, optically linked to the terminal.

14. The improved network unit of claim 13 constructed to interface with a terminal which is a passive splitter for downstream communication.

15. The improved network unit of claim 12 wherein the unit is constructed to send a request at the conclusion of sending a burst of data, the estimate of time being the time required to transmit data received in the interval between the request and the next following initiation of transmission from the unit to the terminal.

16. The improved network unit of claim 12 wherein sets of information are stored by the network unit, each member of a set of local information having one of a plurality of predefined priority levels, the network unit further comprising a buffer of members to be transmitted to the terminal, a plurality of queues for members for transmission to the terminal in each queues dedicated to members of a specific priority, the network unit being constructed to replace data in the buffer with data being received in the interval between a network unit request and a following transmission of data thereby which is of a higher priority when the buffer is full.

17. The improved network unit of claim 12 wherein the network unit is an optical network unit and communicates with a terminal which is an optical line terminal located at a service provider'"'"'s central office and optically linked to the terminal.

18. The improved network unit of claim 17 wherein the network unit id constructed to interface with a terminal that is a passive splitter for downstream communication.

19. The improved network unit of claim 16 wherein the unit is constructed to send a request at the conclusion of sending a burst of data, the estimate of time being the time required to transmit data received in the interval between the request and the next following initiation of transmission from the unit to the terminal.

20. The improved network unit of claim 16 wherein there are three priorities defined, in descending order of priority, as top priority for members which are delay sensitive and have bandwidth guarantees, second priority for members which are not delay sensitive but have bandwidth guarantees, and low priority for members which are not delay sensitive and do not have bandwidth guarantees.

21. In a communication network including a terminal which serves a plurality of downstream network units and receives upstream communications from the network units in respective time slots on a time division basis, the terminal apportioning upstream timeslots among network units by granting a respective timeslot of to network units in response to a request from a network unit, a network unit storing sets of local information received thereby and destined for the terminal, each member of a set of local information having one of a plurality of predefined priority levels, an improved network unit providing service differentiation among information sets of different priority comprising, a buffer of members to be transmitted to the terminal, a plurality of queues for members for transmission to the terminal, each queue dedicated to members of a specific priority, a network unit being constructed to replace data in the buffer with data received in the interval between a network unit request and a following transmission of data thereby which is of a higher priority when the buffer is full,.

22. The improved network unit of claim 21 constructed to have three priorities defined, in descending order of priority, as top priority for members which are delay sensitive and have bandwidth guarantees, second priority for members which are not delay sensitive but have bandwidth guarantees, and third priority for members which are not delay sensitive and do not have bandwidth guarantees.