Nippon Telegraph and Telephone Corporation

Nippon Telegraph & Telephone Corporation of Japan

Osamu Yoshihara

Noriki Miki

Noriyuki Oota

The aim of the present invention is to achieve a low delay and high bandwidth efficiency in an upstream bandwidth and to accurately reflect assured bandwidth in an actual transmitted bandwidth. To achieve this, in the present invention the maximum value and the transmission cycle of a requested bandwidth are set for each service class. The present invention allocates bandwidth to a service path terminating section based on excess allocated bandwidth and requested bandwidth of each service path terminating section. For each service path terminating section the present invention also selects one bandwidth out of a plurality of bandwidths requested by a service path terminating section in such a manner that the sum value of the allocated bandwidths of the plurality of service path terminating sections is within a predetermined range.

Dynamic bandwidth allocation circuit, dynamic bandwidth allocation method, optical network unit, PON system, dynamic bandwidth allocation program and recording medium

In a P2MP system in which upstream bandwidth is shared by a plurality of ONUs, a dynamic bandwidth allocation circuit is provided which reduces the consumption of memory capacity, and avoids the divergence of parameters. A dynamic bandwidth allocation circuit provided in an optical line terminal (OLT) calculates, for each cycle and for each ONU, a target data size (target) which constitutes a target for allocated data size (allocated). Furthermore, taking the time constant of an exponential weighted moving average as &#x3c4;, and taking &#x3b1;=(&#x3c4;&#x2212;1)/(&#x3c4;+1), an ideal allocated data size (ideal) is calculated by ideal=target&#x2212;(&#x3b1;/(1&#x2212;&#x3b1;))&#xb7;excess. Furthermore, an excess allocated data size (excess) per one cycle is calculated by excess=&#x3b1;&#xb7;excess+(1&#x2212;&#x3b1;)&#xb7;(allocated&#x2212;target). If ideal&#x3c;0, the condition that bandwidth allocation is not granted is used for bandwidth allocation.

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Yachiyo, Japan

Osamu Yoshihara