Definition

Fiber Distributed Data Interface (FDDI) is an outdated high-speed networking standard that uses fiber-optic cables. It operates at a maximum speed of 100Mbps and can extend up to 200 kilometers.

History of FDDI

Developed in the 1980S, FDDI was designed to deliver high-speed internet across more expansive geographical areas than local area networks (LAN). It became widely used for campus backbone from its launch to around the mid-1990s because alternative options were slower.

Initially, FDDI involved fiber-optic cables for data transmission, but later versions incorporated copper cables, commonly referred to as copper-distributed data interface (CDDI).

However, Fast Ethernet (which provides similar speed at a lower cost) and Gigabit Ethernet (which is cheaper, faster, and more widespread) have largely replaced FDDI.

FDDI Topology 

FDDI has a dual-ring structure, which enhances reliability and fault tolerance. In this configuration, data travels around the primary ring in one direction while the secondary ring acts as a backup path.

If a device wants to transmit data, it captures the token (digital signals that regulate network access and permissions for data transmission) and sends the data to the rings.

FDDI topology features a ‘dual rings of trees’ design, connecting host computers to the infrastructure device (like a dual attachment station, concentrator, or router), which connects to both rings in the topology.