How to TAP 40/100G BiDi connections

Bandwidth demand in data centers and campus networks is increasing due to growing virtualization. In data centers, this has a particular impact at aggregation points of top-of-rack switches, i.e., from leaf to spine in modern architectures. But in campus networks, too, the load on the uplinks to the core and distribution levels is rising due to the increase in digitization and the increased quantity of networked end devices.

Network managers are trying to meet these increasing demands with 40G and 100G connections. The passive network infrastructure in the form of fiber optic cabling is one of the cost drivers in such projects. In addition, expansions and changes need an extended project lead time. Therefore, the responsible parties prefer to use technologies that can build on the existing base.

BiDi Module approach

To efficiently migrate from 10G to 40G or 100G over short distances on a fiber pair and existing OM3 and OM4 multimode connections with LC connectors, bidirectional (or “BiDi”) modules are available. 

These increase the cost efficiency while shortening the project time: with classic solutions, eight fibers would be required instead of only two with BiDi. The functionality of these modules is based on a passive WDM (Wavelength Division Multiplexing) technology with 850nm and 910nm on both sides. In the 40G variant, each module transmits and receives 20G on each fiber. In contrast, at 100G, each module transmits and receives 50G on each fiber. The two channels are also separated via WDM.