100Gigabit

100gigabit refers to a data transmission rate of 100 gigabits per second (Gbps). In networking, it is most commonly associated with 100 Gigabit Ethernet, a family of standards that enable high-throughput connections for data centers, service providers, and research networks. The term can also describe other protocols capable of sustained 100 Gbps links.

The IEEE 802.3 standardization effort defines several 100GBASE interfaces, including 100GBASE-SR4 for short-range multimode fiber, 100GBASE-LR4 for long-reach single-mode fiber, 100GBASE-ER4 for extended reach, and 100GBASE-CR4 for copper backplanes. These interfaces specify different optics, wavelengths, and reach requirements to suit various deployment scenarios, from intra-rack links to metro backbones.

Common implementation uses multi-lane configurations, such as four 25 Gbps lanes, often combined in a single package known as QSFP28. Earlier, larger form factors such as CFP, CFP2, and CFP4 were used in some core networks. The 100GBASE family supports both short-reach and long-haul deployments, with modern optics enabling high density and scalable port counts in data centers.

Applications and impact: 100G Ethernet provided a practical upgrade path beyond 40G Ethernet, enabling higher bandwidth for cloud services, virtualization, and large-scale analytics. Over time, costs and power consumption have improved, contributing to broader adoption. The technology forms part of Ethernet’s ongoing evolution toward higher speeds, including 400G Ethernet and beyond.