Fiber Distributed Data Interface
FDDI provides a 100 Mbit/s optical standard for data transmission in local area network that can extend in range up to 200 kilometers (120 mi). Although FDDI logical topology is a ring based token network, it did not use the IEEE 802.5 token ring protocol as its basis; instead, its protocol was derived from the IEEE 802.4 token bus timed token protocol.
In addition to covering large geographical areas, FDDI local area networks can support thousands of users. FDDI offers both a Dual-Attached Station (DAS), counter-rotating token ring topology and a Single-Attached Station (SAS), token bus passing ring topology.

→ Fully connected mesh we can also called complete graph. So, it has total number of cable links with n nodes are n(n-1)/2
→ In a star topology total number of cable links are (n-1)

→ In a star topology, each device has a dedicated point-to-point link only to a central controller, usually called a hub.
→ The devices are not directly linked to one another.

A bus is a communication system that transfers data between components inside a computer, or between computers.