The fibernet II ethernet-compatible fiber optic LAN

Fibernet II is a fiber-optic local area network (LAN) having an active-star configuration. It is plug compatible with the 10- Mbit/s coaxial-cable Ethernet LAN at its transceiver cable interface. Ethernet requires the detection of packet collisions; this function is implemented in Fibernet II at the active star node. Collision presence is signaled to the host transceivers with a unique in-band optical signal. Fibernet II features improved electromagnetic immunity, absence of signal radiation from cables, freedom from ground-loop currents due to ground potential differences between remote sites, new network topology options, and a growth path to future broad-band services. This paper describes the Fibernet II experimental system as implemented at the Xerox Palo Alto Research Center. A space-time analysis is presented which confirms that Fibernet II can support a network diameter of over 4.0 km, in contrast to the coax Ethernet which is limited to 2.5 km.