Summary: | 碩士 === 國立臺北科技大學 === 資訊工程系研究所 === 102 === Energy saving techniques, which allow an ONU to reside in the doze or sleep mode, have been proposed for passive optical networks (PONs). In general, if the traffic loading of both downstream and upstream is light, the ONUs should stay in the sleep mode for most of the time. However, if downstream traffic persists while upstream traffic is lightly loaded, the ONUs should reside in the doze mode frequently. This paper proposes a mechanism with full energy transition path, enabling an ONU in any one of the three energy modes to transit to its neighbor mode directly with both forward and backward paths. In addition, this mechanism allows the OLT to be synchronized with ONUs’ energy mode without receiving REPORT message when an ONU transits to a power saving mode. In order to avoid sensitive data being delayed extensively, we classify packets into high and low priorities. While residing in the energy saving mode, the ONU can thus wake up instantaneously if high priority packets arrive. On the other hand, we put an ONU into energy saving mode immediately while the traffic becomes lower. The transition time of waking up from the energy saving mode is ignored in our mechanism. The carried out simulation results have revealed the energy efficiency and frame delay performance with the limited service of IPACT.
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