Energy Efficient VoD with Cache in TWDM PON ring

This work discusses the availability of cache memories for VoD service in Time and Wavelength Division Multiplexed Passive Optical Network (TWDM PON) ring topology. In a unidirectional ring topology with TWDM PON, the wavelength channels are enabled in an anti-cyclic manner through intermediate devices such as Remote Node (RN) and splitter as per traffic requirements. The provision of cache storage at subsystems of ring topology, namely, Optical Line Terminal (OLT), RN, and Optical Network Unit (ONU) enables the users to access the VoD service within reach rather than from a typical video server. Thus, this mechanism reduces the delay as well as power requirements. However, in this paper the analytical emphasis on the ring topology is confined only to power requirements through two situational cases. In the first case, the cache storage at OLT and ONU is only availed. While in the second case, the cache available at RN was also made to use. It is observed that the power consumption in the second case is lesser than in the first case. Due to more decentralization of cache availability in the second case, relatively 70 % more power savings are observed.