Dynamic bandwidth allocation and service differentiation for broadband passive optical networks
First Claim
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.
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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.
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Citations
22 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.
- 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.
- 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.
- 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,.
Specification