Delay; Length - Cabletron Systems 100BASE-FX Cabling Manual

Insertion Loss
The FOIRL specification allows for a total loss of 10.0 dB or less between any two
stations or devices connected by fiber optic cabling. When calculating insertion
loss, you must consider and count any loss introduced by fiber optic splices,
barrel connectors, distribution boxes or other cable management devices. The
typical dB loss for a splice or a connector is less than 1 dB. The loss statistics for
any fiber optic cable management hardware should be available from the
manufacturer.

Delay

If there is any signal path in the overall network whose total one-way propagation
delay exceeds 25.6 s, the Ethernet network is out of specifications, and error
conditions may result. To eliminate propagation delay problems, incorporate
some form of segmentation, such as bridging or routing, into the network to
separate the problem signal paths from one another.

Length

The FOIRL specification limits single mode fiber optic cabling links to a total of 1
km or less. If a single mode fiber optic cable is used to form a link between two
bridges and shares no connection with other Ethernet stations, the total segment
length may reach up to 5 km, assuming all other requirements for a FOIRL
network are met. At lengths over 5 km, propagation delays for the fiber optic link
exceed the 25.6 s limit of Ethernet networks. Cabletron Systems does not
recommend the installation or use of any single mode fiber optic cable segment
that exceeds the FOIRL limitations.
Ethernet FOIRL (Single Mode)
Full-Duplex Ethernet Network Requirements
6-7