FDDI follow on LAN (FFOL)
FDDI Follow On LAN (FFOL) is the third approach within the FDDI standardization activities after FDDI and FDDI II. The standardization process began in the early 1990s with the goal of creating an FDDI backbone architecture that is scalable in transmission speed and capable of carrying FDDI and FDDI II traffic. In the meantime, standardization activities have been discontinued.
The physical layer common to synchronous and asynchronous services will be deployable on existing cabling systems such as FOC or TP.
The planned transmission rates are identical to the standardized Synchronous Data Hierarchy( SDH) transmission rates from wide area, as used in ATM, and range from 155.52 Mbit/s to 2.4 Gbit/s.
According to FDDI II, the isochronous characteristics are realized by a wideband channel (WBC) in the 8- kHz cycle. The asynchronous data traffic is handled by ATM cells. In any case, it is a design goal to be able to provide low-cost LAN connections with FFOL. FFOL will be able to transport FDDI, FDDI-II and ATM data traffic for this purpose.