CDDI stands for Copper Distributed Data Interface, a network communication standard that uses copper cabling to transmit high-speed data based on the Fiber Distributed Data Interface (FDDI) protocol.
Copper Distributed Data Interface (CDDI) was created as a copper-based variant of the Fiber Distributed Data Interface (FDDI) standard, offering similar data transmission capabilities using twisted-pair copper cabling instead of fiber optics. CDDI supported speeds up to 100 megabits per second (Mbps), making it a high-performance solution for backbone and local area network (LAN) applications during its peak use in the 1990s.
The system used shielded or unshielded twisted-pair cables, often Category 5, and employed the same token-passing protocol as FDDI to ensure organized, collision-free data transmission. This deterministic network access method allowed CDDI to maintain efficient bandwidth management and predictable performance across complex network environments. Though eventually surpassed by Ethernet technologies offering higher speeds and simpler implementation, CDDI played a key transitional role in the evolution of copper-based networking standards.
In commercial and industrial contexts, CDDI enabled facilities to establish high-speed communication networks using existing copper infrastructure, reducing costs compared to fiber installations. It was commonly deployed in enterprise campuses, data centers, and industrial automation systems that required reliable, low-latency communication between servers, switches, and control systems.
CDDI was developed and standardized by the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO) as part of the broader FDDI family of protocols.
Introduced in the early 1990s, CDDI was developed to extend the benefits of FDDI to copper-based cabling systems. It gained traction in enterprise and industrial applications as an affordable alternative to fiber optic networks. However, with the rapid advancement of Ethernet technologies, particularly Fast and Gigabit Ethernet, CDDI became largely obsolete by the late 1990s. Despite this, it remains an important milestone in the development of copper-based high-speed networking.