In this configuration, the requirements of the network extend beyond the five
segments and four repeaters allowed by the IEEE 802.3 rules. This configuration
is supported by using a bridge to create an extended LAN. The two LANs on
either side of the bridge may each contain up to five segments and four repeaters;
however, they are able to communicate with one another as if they were on a
single LAN.
Installed Fiber Constraints
In addition to following the IEEE 802.3 rules that ensure proper protocol
operation, the user must also ensure that the fiber-optic cable plant is properly
designed. Although the IEEE 802.3 standard allows for a maximum length of
1000 meters (FOIRL) or 2000 meters (10Base-FL), the fiber-optic segments may
be limited by the following characteristics of installed fiber:
•
Power budget
•
Link-loss
•
Wavelength
•
Bandwidth
The maximum link distance could be further restricted by the number of splices,
interconnects, and cross-connect administration points. Refer to the DECconnect
System Fiber Optic Planning and Configuration guide for instructions on how to
calculate the link certification value for each segment.
Configuring the DECrepeater 90FA 2–5