Bandwidth allocation device and method to guarantee QoS in ethernet passive optical access network

A device for allocating bandwidth to guarantee QoS (quality of service) in an Ethernet passive optical network, the device comprising:

• a plurality of optical network units for classifying uplink data to be transmitted to an optical line terminal into a plurality of classes according to a predetermined priority and transmitting the classified uplink data, and receiving an allocated bandwidth required for each of the classes from the optical line terminal;
• and
• an optical line terminal for distributing bandwidths required for a highest priority class among the plurality classes from an entire available uplink bandwidth to the optical network units, dynamically distributing bandwidths for a secondary priority class among the plurality of classes using the remained bandwidth after distributing the requested bandwidths to the highest priority class, and subsequently, dynamically distributing bandwidths for one or more other classes,
• wherein when a sum of requested bandwidths for the secondary class requested by the optical network units is greater than the remained bandwidth,
• for each optical network unit, if a smaller value between a predefined maximum usable bandwidth of the optical network unit and a bandwidth requested by the optical network unit is greater than an available bandwidth (avail_BWAF) to be allocated to the secondary class, the optical line terminal is to allocate a bandwidth to the optical network unit in proportional to a smaller value between a minimum guaranteed bandwidth of the optical network unit and the requested bandwidth requested by the optical network unit.

An optical network unit (ONU) comprising:

• a plurality of priority queues for classifying uplink data to be transmitted to an optical line terminal (OLT) into a plurality of classes according to a predetermined data priority, and storing the classified uplink data;
• and
• a scheduler for transmitting the uplink data stored in the priority queue according to bandwidth allocation information received from the optical line terminal,
• wherein a bandwidth allocated from the optical line terminal is allocated by distributing bandwidths required for a highest priority class among the classes from an entire available uplink bandwidth, dynamically distributing bandwidths for a secondary priority class among the plurality of classes using the remained bandwidth after distributing the requested bandwidths to the highest priority class, and subsequently, dynamically distributing bandwidths for one or more other classes,
• wherein when a sum of requested bandwidths for the secondary class requested by the optical network units is greater than the remained bandwidth,
• if a smaller value between a predefined maximum usable bandwidth of the optical network unit and a bandwidth requested by the optical network unit is greater than an available bandwidth (avail_BWAF) to be allocated to the secondary class, the optical line terminal is to allocate a bandwidth to the optical network unit in proportional to a smaller value between a minimum guaranteed bandwidth of the optical network unit and the requested bandwidth requested by the optical network unit.

An optical line terminal (OLT) comprising:

• a storing unit for classifying uplink frames to be transmitted from a plurality of optical network units (ONUs) into a plurality of classes according to a predetermined priority, and storing a bandwidth managing table containing information about bandwidths requested according to predetermined priorities for each of the optical network units;
• and
• a bandwidth allocating unit for distributing bandwidths required for a highest priority class among the classes from an entire available uplink bandwidth, dynamically distributing bandwidths for a secondary priority class among the plurality of classes using the remained bandwidth after distributing the requested bandwidths to the highest priority class, and subsequently, dynamically distributing bandwidths for one or more other classes,
• wherein when a sum of requested bandwidths for the secondary class requested by the optical network units is greater than the remained bandwidth,
• for each optical network unit, if a smaller value between a predefined maximum usable bandwidth of the optical network unit and a bandwidth requested by the optical network unit is greater than an available bandwidth (avail_BWAF) to be allocated to the secondary class, the optical line terminal is to allocate a bandwidth to the optical network unit in proportional to a smaller value between a minimum guaranteed bandwidth of the optical network unit and the requested bandwidth requested by the optical network unit.