Overview

 A much simpler and inherently CAPEX and OPEX saving form of transport is passive transport. Here signal generation and signal transport is done within the same equipment, e.g. an Ethernet Switch. Since signal conversion by itself does not add any benefits but only tremendous costs, risk of failure and in the best case only maintains the signal quality (but does not approve it) it is avoided.

So instead of using local transceivers and converting their signals in a rather complicated manner via transponder cards to the line transceivers, the line transceivers are directly plugged into the terminal equipment (e.g. the Ethernet Switch). Doing so makes everything but the line transceivers and the passive optical multiplexers obsolete and is therefore, taken out.

It is evident that this means of transport not only saves >50% of CAPEX by eliminating mandatory parts (chassis, power supplies, transponder cards etc.) but that savings on the OPEX side are even bigger: No transport equipment software (SNMP management) needs to be integrated, operated, maintained and updated, much fewer electronic parts exponentially increase MTBF (Meantime Between Failure) numbers reducing down times and costly maintenances and support services. Last but not least, electric power consumption can be reduced by easily >50%: First of all as there is no extra transport system to power, second, since there is no extra heat generated cooling through air-conditioning can be largely reduced.

Apart from CAPEX and OPEX savings aspects a Passive Transport Solution inherently also reduces latency times in the network and will provide a better network performance than the active counterparts.

Passive WDM Solutions not only provide the lowest cost option for data transport but also proofed a much higher reliability than the active counterparts. The passive WDM systems are indirectly monitored via the Ethernet Terminal equipment (e.g. Switch) without losing network management options. In contrast the absence of additional software reduces OPEX as well as lower maintenance efforts are needed. Last but not least, a passive WDM solution drastically reduces energy consumption as it needs no additional active parts but most of all since it makes air-conditioning obsolete.