Network side transmission apparatus and method for controlling variable traffic rate by dynamic bandwidth allocation

A network side transmission apparatus designating timings of transfer of information for a plurality of terminal units on a user side, receiving information transferred from said plurality of terminal units by time division multiplexing at the transfer timings, and controlling variable rate traffic by dynamic bandwidth allocation, comprising:

• a queue length extracting function unit for receiving notifications relating to the queue lengths of information stored for connections in buffers of the terminal units from the terminal units and extracting the queue lengths;
• a parameter setting function unit for setting at least one of a contracted parameter relating to a sustainable cell rate, a contracted parameter relating to a peak cell rate, and contracted parameters relating to fluctuation values allowed for the sustainable cell rate and peak cell rate for the connections contracted for with the terminal units;
• a parameter managing memory for storing at least the queue length information and contracted parameter information input from the queue length extracting function unit and the parameter setting function unit;
• and
• a bandwidth calculating function unit for periodically calculating the allocated bandwidths for the connections so that the contracted parameters are observed and re-storing the results of the calculation in the parameter managing memory.

A method of control of variable rate traffic by dynamic bandwidth allocation in a network side transmission apparatus which designates the timings of transfer of information for a plurality of terminal units on a user side and receives information transferred from these terminal units by time division multiplexing at the designated transfer timings, comprising the steps of:

• receiving amounts of information to be transferred for a connection stored in each of the terminal units;
• computing the allocated bandwidth based on the received amounts of information to be transferred so that at least a contracted parameter relating to a sustainable cell rate and a contracted parameter relating to a fluctuation value allowed for the sustainable cell rate are observed among contracted parameters relating to the sustainable cell rate and a peak cell rate and contracted parameters relating to fluctuation values allowed for the sustainable cell rate and peak cell rate preset for the connection;
• and
• assigning the computed allocated bandwidth to the connection and notifying each of the terminal units.

A communication system comprised of:

• a plurality of terminal units at a user side for reading and transferring information by time division multiplexing from each of internal buffers provided for each of connections at designated timing of transfer of information;
• a network side control apparatus for designating said timing of transfer of information for each of said terminal units, receiving information read and transferred from each said buffer in each said terminal unit, and controlling variable rate traffic by dynamic bandwidth allocation;
• and
• a time division multiplexing transmission line for transferring polling information designating said transfer timing to each of said plurality of terminal units and transferring information from each said buffer to said network side transmission apparatus at the designated transfer timings;
• said network side transmission apparatus comprising
• an allocating means for assigning allocated bandwidth for transfer to each of the connection periodically according to amounts of information to be transferred for each said connection stored in each said buffer and
• a computing means for computing the allocated bandwidth so that at least a contracted parameter relating to a sustainable cell rate and a contracted parameter relating to a fluctuation value allowed for the sustainable cell rate are observed among contracted parameters relating to the sustainable cell rate and a peak cell rate and contracted parameters relating to the fluctuation values allowed for the sustainable cell rate and peak cell rate preset for the connections.