Nortel Networks 10292FA - Manual (Page 29)

Chapter 2 Calculating transmission distance 29
Installation and Networking Guidelines for Optical Routing
Procedure
To calculate the maximum transmission distance for a proposed network
configuration:
1 Identify all points where signal strength will be lost.
2 Calculate the expected loss for each point.
3 Find total passive loss by adding the expected losses together.
4 Find remaining signal strength by subtracting passive loss, and system margin
from total system budget.
5 Find maximum transmission distance by dividing remaining signal strength
by expected fiber attenuation/km.
Point-to-point transmission distance
The following factors affect signal strength, and determine point-to-point link
budget and maximum transmission distance for the network in
Figure 11 :
• CWDM OMUX mux loss
• CWDM OMUX demux loss
• Fiber attenuation
The Ethernet switch host does not have to be near the CWDM OMUX, and the
CWDM OMUX does not regenerate signal. Therefore, maximum transmission
distance is from GBIC to GBIC.
Figure 11 Point-to-point network configuration example
OMUX-8 OMUX-8
GBIC GBIC
Transmission Distance
(GBIC to GBIC)