Patent ID: 7031343

Claim:
A point-to-multipoint optical communications system comprising: an optical line terminal (OLT); and a plurality of optical network units (ONUs) connected to said OLT by a passive optical network in which downstream data is transmitted from said OLT to said ONUs over said passive optical network and upstream data is transmitted from said ONUs to said OLT over said passive optical network: said OLT transmitting downstream data over said passive optical network in variable-length downstream packets; said ONUs transmitting downstream data over said passive optical network within ONU-specific time slots utilizing time division multiplexing, wherein said ONU-specific time slots are filled with multiple variable-length upstream packets; said OLT includes: a fragment buffer for storing packet fragments that have been transmitted upstream from said ONUs; and fragment logic for: identifying said end-of-packet-fragment code of said first packet fragment; buffering said first packed fragment in said OLT fragment buffer; identifying said start-of-packet-fragment code of said first packet fragment; reconstructing said variable-length upstream packet from said first and second packet fragments; said ONUs include: fragment buffers for storing packet fragments that are to be transmitted upstream from said ONUs; and fragment logic for: splitting a variable-length upstream packet into first and second packet fragments; and adding an end-of-packet-fragment code to said first packet fragment and adding a start-of-packet-fragment code to said second packet fragment.