Nortel Networks 10292FA - Manual (Page 31)

Chapter 2 Calculating transmission distance 31
Installation and Networking Guidelines for Optical Routing
As it passes from point A to point B (the most remote points in the mesh ring
network example in
Figure 12 ), the signal is expected to lose strength in the fiber
optic cable, and in each connection between the individual CWDM OADMs and
CWDM GBICs.
The following factors determine mesh ring link budget and transmission distance
for the network in
Figure 12 :
• CWDM OADM insertion add loss
• CWDM OADM insertion drop loss
• Passthrough insertion loss at intermediate nodes
• Fiber attenuation of 0.25 dB per kilometer
The Ethernet switch host does not have to be near the CWDM OADM, and the
CWDM OADM does not regenerate signal. Therefore, maximum transmission
distance is from GBIC to GBIC.
The number of OADMs supported is based on loss budget calculations.
Figure 12 Mesh ring network configuration
OADM
OADM
OADM
OADM
OADM
OADM
OADM OADM
A B
Transmission Distance
(GBIC to GBIC)
GBIC GBIC