Fiber Distributed Data Interface (2)
topology: dual ring (for redundancy); during normal operation, the primary ring is used for data transmission, the secondary ring remains idle; traffic on each ring flows in opposite directions (called counter-rotating);stations act as repeaters
DAS - Dual Attached Station is attached to both rings
SAS - Single Attached Station is attached only to the primary ring
connectors: ST, MIC, SMA906; status: mature, reliable and proven
transition modes: asynchronous - traffic is not prioritized; synchronous - allows for prioritization of time-sensitive traffic; circuit-based (in FDDI II only) -allows for dedicated communication line with guaranteed bandwidth