When the network has to span more than a standard short-reach optic can handle, this 100G 4WDM 20 QSFP28 module gives you the distance headroom to keep the architecture simple. It supports 100 GbE over single-mode fiber with LC connectivity and a 20 km reach, making it a practical fit for campus backbones, metro aggregation, and inter-site links. The value here is not just speed. It is the ability to preserve a direct Ethernet path across longer runs without introducing extra transport layers or redesigning the fiber plant. For teams building high-density switching environments, the QSFP28 form factor keeps port usage efficient while supporting the reach required for production traffic. Compared with lower-reach optics, this module is specified for deployments where the physical layout, not the switch, sets the challenge. It is the right choice when you need 100 GbE performance across a wider footprint and want to avoid the cost and complexity of overbuilding the link later.