A Synchronous Fiber Optic Ring Local Area Network for Multigigabit/s Mixed-Traffic Communication

A synchronous-ring fiber optic local area network is reported that facilitates the simultaneous transmission of packet and real-time traffic at gigabit/s rates, minimizes the amount of high-speed logic, and simplifies the user interface to the network. The novelty of the technique is based on 1) suspending in transit around the ring´s circumference an integral number of data frames and 2) achieving this condition by skewing the frame clock rate a small amount ( < 1 percent). Rather than use the whole data frame as one packet destined to a specific user (as in a slotted ring), we instead time multiplex many individual channels into the data frame. This technique only becomes feasible for local networks as data rates approach the Gbit/s range. This departure from other synchronous rings results in several advantages both in terms of system performance and hardware simplicity.